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diff --git a/docs/AttributeReference.rst b/docs/AttributeReference.rst index db4812afdaa0..a763ddeaeb10 100644 --- a/docs/AttributeReference.rst +++ b/docs/AttributeReference.rst @@ -1,3119 +1,13 @@ .. ------------------------------------------------------------------- NOTE: This file is automatically generated by running clang-tblgen - -gen-attr-docs. Do not edit this file by hand!! + -gen-attr-docs. Do not edit this file by hand!! The contents for + this file are automatically generated by a server-side process. + + Please do not commit this file. The file exists for local testing + purposes only. ------------------------------------------------------------------- =================== Attributes in Clang -=================== -.. contents:: - :local: - -Introduction -============ - -This page lists the attributes currently supported by Clang. - -Function Attributes -=================== - - -interrupt ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Clang supports the GNU style ``__attribute__((interrupt("TYPE")))`` attribute on -ARM targets. This attribute may be attached to a function definition and -instructs the backend to generate appropriate function entry/exit code so that -it can be used directly as an interrupt service routine. - -The parameter passed to the interrupt attribute is optional, but if -provided it must be a string literal with one of the following values: "IRQ", -"FIQ", "SWI", "ABORT", "UNDEF". - -The semantics are as follows: - -- If the function is AAPCS, Clang instructs the backend to realign the stack to - 8 bytes on entry. This is a general requirement of the AAPCS at public - interfaces, but may not hold when an exception is taken. Doing this allows - other AAPCS functions to be called. -- If the CPU is M-class this is all that needs to be done since the architecture - itself is designed in such a way that functions obeying the normal AAPCS ABI - constraints are valid exception handlers. -- If the CPU is not M-class, the prologue and epilogue are modified to save all - non-banked registers that are used, so that upon return the user-mode state - will not be corrupted. Note that to avoid unnecessary overhead, only - general-purpose (integer) registers are saved in this way. If VFP operations - are needed, that state must be saved manually. - - Specifically, interrupt kinds other than "FIQ" will save all core registers - except "lr" and "sp". "FIQ" interrupts will save r0-r7. -- If the CPU is not M-class, the return instruction is changed to one of the - canonical sequences permitted by the architecture for exception return. Where - possible the function itself will make the necessary "lr" adjustments so that - the "preferred return address" is selected. - - Unfortunately the compiler is unable to make this guarantee for an "UNDEF" - handler, where the offset from "lr" to the preferred return address depends on - the execution state of the code which generated the exception. In this case - a sequence equivalent to "movs pc, lr" will be used. - - -abi_tag (gnu::abi_tag) ----------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``abi_tag`` attribute can be applied to a function, variable, class or -inline namespace declaration to modify the mangled name of the entity. It gives -the ability to distinguish between different versions of the same entity but -with different ABI versions supported. For example, a newer version of a class -could have a different set of data members and thus have a different size. Using -the ``abi_tag`` attribute, it is possible to have different mangled names for -a global variable of the class type. Therefor, the old code could keep using -the old manged name and the new code will use the new mangled name with tags. - - -acquire_capability (acquire_shared_capability, clang::acquire_capability, clang::acquire_shared_capability) ------------------------------------------------------------------------------------------------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Marks a function as acquiring a capability. - - -alloc_size (gnu::alloc_size) ----------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``alloc_size`` attribute can be placed on functions that return pointers in -order to hint to the compiler how many bytes of memory will be available at the -returned poiner. ``alloc_size`` takes one or two arguments. - -- ``alloc_size(N)`` implies that argument number N equals the number of - available bytes at the returned pointer. -- ``alloc_size(N, M)`` implies that the product of argument number N and - argument number M equals the number of available bytes at the returned - pointer. - -Argument numbers are 1-based. - -An example of how to use ``alloc_size`` - -.. code-block:: c - - void *my_malloc(int a) __attribute__((alloc_size(1))); - void *my_calloc(int a, int b) __attribute__((alloc_size(1, 2))); - - int main() { - void *const p = my_malloc(100); - assert(__builtin_object_size(p, 0) == 100); - void *const a = my_calloc(20, 5); - assert(__builtin_object_size(a, 0) == 100); - } - -.. Note:: This attribute works differently in clang than it does in GCC. - Specifically, clang will only trace ``const`` pointers (as above); we give up - on pointers that are not marked as ``const``. In the vast majority of cases, - this is unimportant, because LLVM has support for the ``alloc_size`` - attribute. However, this may cause mildly unintuitive behavior when used with - other attributes, such as ``enable_if``. - - -interrupt ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Clang supports the GNU style ``__attribute__((interrupt))`` attribute on -x86/x86-64 targets.The compiler generates function entry and exit sequences -suitable for use in an interrupt handler when this attribute is present. -The 'IRET' instruction, instead of the 'RET' instruction, is used to return -from interrupt or exception handlers. All registers, except for the EFLAGS -register which is restored by the 'IRET' instruction, are preserved by the -compiler. - -Any interruptible-without-stack-switch code must be compiled with --mno-red-zone since interrupt handlers can and will, because of the -hardware design, touch the red zone. - -1. interrupt handler must be declared with a mandatory pointer argument: - - .. code-block:: c - - struct interrupt_frame - { - uword_t ip; - uword_t cs; - uword_t flags; - uword_t sp; - uword_t ss; - }; - - __attribute__ ((interrupt)) - void f (struct interrupt_frame *frame) { - ... - } - -2. exception handler: - - The exception handler is very similar to the interrupt handler with - a different mandatory function signature: - - .. code-block:: c - - __attribute__ ((interrupt)) - void f (struct interrupt_frame *frame, uword_t error_code) { - ... - } - - and compiler pops 'ERROR_CODE' off stack before the 'IRET' instruction. - - The exception handler should only be used for exceptions which push an - error code and all other exceptions must use the interrupt handler. - The system will crash if the wrong handler is used. - - -assert_capability (assert_shared_capability, clang::assert_capability, clang::assert_shared_capability) -------------------------------------------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Marks a function that dynamically tests whether a capability is held, and halts -the program if it is not held. - - -assume_aligned (gnu::assume_aligned) ------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Use ``__attribute__((assume_aligned(<alignment>[,<offset>]))`` on a function -declaration to specify that the return value of the function (which must be a -pointer type) has the specified offset, in bytes, from an address with the -specified alignment. The offset is taken to be zero if omitted. - -.. code-block:: c++ - - // The returned pointer value has 32-byte alignment. - void *a() __attribute__((assume_aligned (32))); - - // The returned pointer value is 4 bytes greater than an address having - // 32-byte alignment. - void *b() __attribute__((assume_aligned (32, 4))); - -Note that this attribute provides information to the compiler regarding a -condition that the code already ensures is true. It does not cause the compiler -to enforce the provided alignment assumption. - - -availability ------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -The ``availability`` attribute can be placed on declarations to describe the -lifecycle of that declaration relative to operating system versions. Consider -the function declaration for a hypothetical function ``f``: - -.. code-block:: c++ - - void f(void) __attribute__((availability(macos,introduced=10.4,deprecated=10.6,obsoleted=10.7))); - -The availability attribute states that ``f`` was introduced in Mac OS X 10.4, -deprecated in Mac OS X 10.6, and obsoleted in Mac OS X 10.7. This information -is used by Clang to determine when it is safe to use ``f``: for example, if -Clang is instructed to compile code for Mac OS X 10.5, a call to ``f()`` -succeeds. If Clang is instructed to compile code for Mac OS X 10.6, the call -succeeds but Clang emits a warning specifying that the function is deprecated. -Finally, if Clang is instructed to compile code for Mac OS X 10.7, the call -fails because ``f()`` is no longer available. - -The availability attribute is a comma-separated list starting with the -platform name and then including clauses specifying important milestones in the -declaration's lifetime (in any order) along with additional information. Those -clauses can be: - -introduced=\ *version* - The first version in which this declaration was introduced. - -deprecated=\ *version* - The first version in which this declaration was deprecated, meaning that - users should migrate away from this API. - -obsoleted=\ *version* - The first version in which this declaration was obsoleted, meaning that it - was removed completely and can no longer be used. - -unavailable - This declaration is never available on this platform. - -message=\ *string-literal* - Additional message text that Clang will provide when emitting a warning or - error about use of a deprecated or obsoleted declaration. Useful to direct - users to replacement APIs. - -replacement=\ *string-literal* - Additional message text that Clang will use to provide Fix-It when emitting - a warning about use of a deprecated declaration. The Fix-It will replace - the deprecated declaration with the new declaration specified. - -Multiple availability attributes can be placed on a declaration, which may -correspond to different platforms. Only the availability attribute with the -platform corresponding to the target platform will be used; any others will be -ignored. If no availability attribute specifies availability for the current -target platform, the availability attributes are ignored. Supported platforms -are: - -``ios`` - Apple's iOS operating system. The minimum deployment target is specified by - the ``-mios-version-min=*version*`` or ``-miphoneos-version-min=*version*`` - command-line arguments. - -``macos`` - Apple's Mac OS X operating system. The minimum deployment target is - specified by the ``-mmacosx-version-min=*version*`` command-line argument. - ``macosx`` is supported for backward-compatibility reasons, but it is - deprecated. - -``tvos`` - Apple's tvOS operating system. The minimum deployment target is specified by - the ``-mtvos-version-min=*version*`` command-line argument. - -``watchos`` - Apple's watchOS operating system. The minimum deployment target is specified by - the ``-mwatchos-version-min=*version*`` command-line argument. - -A declaration can typically be used even when deploying back to a platform -version prior to when the declaration was introduced. When this happens, the -declaration is `weakly linked -<https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPFrameworks/Concepts/WeakLinking.html>`_, -as if the ``weak_import`` attribute were added to the declaration. A -weakly-linked declaration may or may not be present a run-time, and a program -can determine whether the declaration is present by checking whether the -address of that declaration is non-NULL. - -The flag ``strict`` disallows using API when deploying back to a -platform version prior to when the declaration was introduced. An -attempt to use such API before its introduction causes a hard error. -Weakly-linking is almost always a better API choice, since it allows -users to query availability at runtime. - -If there are multiple declarations of the same entity, the availability -attributes must either match on a per-platform basis or later -declarations must not have availability attributes for that -platform. For example: - -.. code-block:: c - - void g(void) __attribute__((availability(macos,introduced=10.4))); - void g(void) __attribute__((availability(macos,introduced=10.4))); // okay, matches - void g(void) __attribute__((availability(ios,introduced=4.0))); // okay, adds a new platform - void g(void); // okay, inherits both macos and ios availability from above. - void g(void) __attribute__((availability(macos,introduced=10.5))); // error: mismatch - -When one method overrides another, the overriding method can be more widely available than the overridden method, e.g.,: - -.. code-block:: objc - - @interface A - - (id)method __attribute__((availability(macos,introduced=10.4))); - - (id)method2 __attribute__((availability(macos,introduced=10.4))); - @end - - @interface B : A - - (id)method __attribute__((availability(macos,introduced=10.3))); // okay: method moved into base class later - - (id)method __attribute__((availability(macos,introduced=10.5))); // error: this method was available via the base class in 10.4 - @end - - -_Noreturn ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -A function declared as ``_Noreturn`` shall not return to its caller. The -compiler will generate a diagnostic for a function declared as ``_Noreturn`` -that appears to be capable of returning to its caller. - - -noreturn --------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","X","","", "" - -A function declared as ``[[noreturn]]`` shall not return to its caller. The -compiler will generate a diagnostic for a function declared as ``[[noreturn]]`` -that appears to be capable of returning to its caller. - - -carries_dependency ------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``carries_dependency`` attribute specifies dependency propagation into and -out of functions. - -When specified on a function or Objective-C method, the ``carries_dependency`` -attribute means that the return value carries a dependency out of the function, -so that the implementation need not constrain ordering upon return from that -function. Implementations of the function and its caller may choose to preserve -dependencies instead of emitting memory ordering instructions such as fences. - -Note, this attribute does not change the meaning of the program, but may result -in generation of more efficient code. - - -convergent (clang::convergent) ------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``convergent`` attribute can be placed on a function declaration. It is -translated into the LLVM ``convergent`` attribute, which indicates that the call -instructions of a function with this attribute cannot be made control-dependent -on any additional values. - -In languages designed for SPMD/SIMT programming model, e.g. OpenCL or CUDA, -the call instructions of a function with this attribute must be executed by -all work items or threads in a work group or sub group. - -This attribute is different from ``noduplicate`` because it allows duplicating -function calls if it can be proved that the duplicated function calls are -not made control-dependent on any additional values, e.g., unrolling a loop -executed by all work items. - -Sample usage: -.. code-block:: c - - void convfunc(void) __attribute__((convergent)); - // Setting it as a C++11 attribute is also valid in a C++ program. - // void convfunc(void) [[clang::convergent]]; - - -deprecated (gnu::deprecated) ----------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","X","", "" - -The ``deprecated`` attribute can be applied to a function, a variable, or a -type. This is useful when identifying functions, variables, or types that are -expected to be removed in a future version of a program. - -Consider the function declaration for a hypothetical function ``f``: - -.. code-block:: c++ - - void f(void) __attribute__((deprecated("message", "replacement"))); - -When spelled as `__attribute__((deprecated))`, the deprecated attribute can have -two optional string arguments. The first one is the message to display when -emitting the warning; the second one enables the compiler to provide a Fix-It -to replace the deprecated name with a new name. Otherwise, when spelled as -`[[gnu::deprecated]] or [[deprecated]]`, the attribute can have one optional -string argument which is the message to display when emitting the warning. - - -diagnose_if ------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -The ``diagnose_if`` attribute can be placed on function declarations to emit -warnings or errors at compile-time if calls to the attributed function meet -certain user-defined criteria. For example: - -.. code-block:: c - - void abs(int a) - __attribute__((diagnose_if(a >= 0, "Redundant abs call", "warning"))); - void must_abs(int a) - __attribute__((diagnose_if(a >= 0, "Redundant abs call", "error"))); - - int val = abs(1); // warning: Redundant abs call - int val2 = must_abs(1); // error: Redundant abs call - int val3 = abs(val); - int val4 = must_abs(val); // Because run-time checks are not emitted for - // diagnose_if attributes, this executes without - // issue. - - -``diagnose_if`` is closely related to ``enable_if``, with a few key differences: - -* Overload resolution is not aware of ``diagnose_if`` attributes: they're - considered only after we select the best candidate from a given candidate set. -* Function declarations that differ only in their ``diagnose_if`` attributes are - considered to be redeclarations of the same function (not overloads). -* If the condition provided to ``diagnose_if`` cannot be evaluated, no - diagnostic will be emitted. - -Otherwise, ``diagnose_if`` is essentially the logical negation of ``enable_if``. - -As a result of bullet number two, ``diagnose_if`` attributes will stack on the -same function. For example: - -.. code-block:: c - - int foo() __attribute__((diagnose_if(1, "diag1", "warning"))); - int foo() __attribute__((diagnose_if(1, "diag2", "warning"))); - - int bar = foo(); // warning: diag1 - // warning: diag2 - int (*fooptr)(void) = foo; // warning: diag1 - // warning: diag2 - - constexpr int supportsAPILevel(int N) { return N < 5; } - int baz(int a) - __attribute__((diagnose_if(!supportsAPILevel(10), - "Upgrade to API level 10 to use baz", "error"))); - int baz(int a) - __attribute__((diagnose_if(!a, "0 is not recommended.", "warning"))); - - int (*bazptr)(int) = baz; // error: Upgrade to API level 10 to use baz - int v = baz(0); // error: Upgrade to API level 10 to use baz - -Query for this feature with ``__has_attribute(diagnose_if)``. - - -disable_tail_calls (clang::disable_tail_calls) ----------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``disable_tail_calls`` attribute instructs the backend to not perform tail call optimization inside the marked function. - -For example: - - .. code-block:: c - - int callee(int); - - int foo(int a) __attribute__((disable_tail_calls)) { - return callee(a); // This call is not tail-call optimized. - } - -Marking virtual functions as ``disable_tail_calls`` is legal. - - .. code-block:: c++ - - int callee(int); - - class Base { - public: - [[clang::disable_tail_calls]] virtual int foo1() { - return callee(); // This call is not tail-call optimized. - } - }; - - class Derived1 : public Base { - public: - int foo1() override { - return callee(); // This call is tail-call optimized. - } - }; - - -enable_if ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -.. Note:: Some features of this attribute are experimental. The meaning of - multiple enable_if attributes on a single declaration is subject to change in - a future version of clang. Also, the ABI is not standardized and the name - mangling may change in future versions. To avoid that, use asm labels. - -The ``enable_if`` attribute can be placed on function declarations to control -which overload is selected based on the values of the function's arguments. -When combined with the ``overloadable`` attribute, this feature is also -available in C. - -.. code-block:: c++ - - int isdigit(int c); - int isdigit(int c) __attribute__((enable_if(c <= -1 || c > 255, "chosen when 'c' is out of range"))) __attribute__((unavailable("'c' must have the value of an unsigned char or EOF"))); - - void foo(char c) { - isdigit(c); - isdigit(10); - isdigit(-10); // results in a compile-time error. - } - -The enable_if attribute takes two arguments, the first is an expression written -in terms of the function parameters, the second is a string explaining why this -overload candidate could not be selected to be displayed in diagnostics. The -expression is part of the function signature for the purposes of determining -whether it is a redeclaration (following the rules used when determining -whether a C++ template specialization is ODR-equivalent), but is not part of -the type. - -The enable_if expression is evaluated as if it were the body of a -bool-returning constexpr function declared with the arguments of the function -it is being applied to, then called with the parameters at the call site. If the -result is false or could not be determined through constant expression -evaluation, then this overload will not be chosen and the provided string may -be used in a diagnostic if the compile fails as a result. - -Because the enable_if expression is an unevaluated context, there are no global -state changes, nor the ability to pass information from the enable_if -expression to the function body. For example, suppose we want calls to -strnlen(strbuf, maxlen) to resolve to strnlen_chk(strbuf, maxlen, size of -strbuf) only if the size of strbuf can be determined: - -.. code-block:: c++ - - __attribute__((always_inline)) - static inline size_t strnlen(const char *s, size_t maxlen) - __attribute__((overloadable)) - __attribute__((enable_if(__builtin_object_size(s, 0) != -1))), - "chosen when the buffer size is known but 'maxlen' is not"))) - { - return strnlen_chk(s, maxlen, __builtin_object_size(s, 0)); - } - -Multiple enable_if attributes may be applied to a single declaration. In this -case, the enable_if expressions are evaluated from left to right in the -following manner. First, the candidates whose enable_if expressions evaluate to -false or cannot be evaluated are discarded. If the remaining candidates do not -share ODR-equivalent enable_if expressions, the overload resolution is -ambiguous. Otherwise, enable_if overload resolution continues with the next -enable_if attribute on the candidates that have not been discarded and have -remaining enable_if attributes. In this way, we pick the most specific -overload out of a number of viable overloads using enable_if. - -.. code-block:: c++ - - void f() __attribute__((enable_if(true, ""))); // #1 - void f() __attribute__((enable_if(true, ""))) __attribute__((enable_if(true, ""))); // #2 - - void g(int i, int j) __attribute__((enable_if(i, ""))); // #1 - void g(int i, int j) __attribute__((enable_if(j, ""))) __attribute__((enable_if(true))); // #2 - -In this example, a call to f() is always resolved to #2, as the first enable_if -expression is ODR-equivalent for both declarations, but #1 does not have another -enable_if expression to continue evaluating, so the next round of evaluation has -only a single candidate. In a call to g(1, 1), the call is ambiguous even though -#2 has more enable_if attributes, because the first enable_if expressions are -not ODR-equivalent. - -Query for this feature with ``__has_attribute(enable_if)``. - -Note that functions with one or more ``enable_if`` attributes may not have -their address taken, unless all of the conditions specified by said -``enable_if`` are constants that evaluate to ``true``. For example: - -.. code-block:: c - - const int TrueConstant = 1; - const int FalseConstant = 0; - int f(int a) __attribute__((enable_if(a > 0, ""))); - int g(int a) __attribute__((enable_if(a == 0 || a != 0, ""))); - int h(int a) __attribute__((enable_if(1, ""))); - int i(int a) __attribute__((enable_if(TrueConstant, ""))); - int j(int a) __attribute__((enable_if(FalseConstant, ""))); - - void fn() { - int (*ptr)(int); - ptr = &f; // error: 'a > 0' is not always true - ptr = &g; // error: 'a == 0 || a != 0' is not a truthy constant - ptr = &h; // OK: 1 is a truthy constant - ptr = &i; // OK: 'TrueConstant' is a truthy constant - ptr = &j; // error: 'FalseConstant' is a constant, but not truthy - } - -Because ``enable_if`` evaluation happens during overload resolution, -``enable_if`` may give unintuitive results when used with templates, depending -on when overloads are resolved. In the example below, clang will emit a -diagnostic about no viable overloads for ``foo`` in ``bar``, but not in ``baz``: - -.. code-block:: c++ - - double foo(int i) __attribute__((enable_if(i > 0, ""))); - void *foo(int i) __attribute__((enable_if(i <= 0, ""))); - template <int I> - auto bar() { return foo(I); } - - template <typename T> - auto baz() { return foo(T::number); } - - struct WithNumber { constexpr static int number = 1; }; - void callThem() { - bar<sizeof(WithNumber)>(); - baz<WithNumber>(); - } - -This is because, in ``bar``, ``foo`` is resolved prior to template -instantiation, so the value for ``I`` isn't known (thus, both ``enable_if`` -conditions for ``foo`` fail). However, in ``baz``, ``foo`` is resolved during -template instantiation, so the value for ``T::number`` is known. - - -flatten (gnu::flatten) ----------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``flatten`` attribute causes calls within the attributed function to -be inlined unless it is impossible to do so, for example if the body of the -callee is unavailable or if the callee has the ``noinline`` attribute. - - -format (gnu::format) --------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Clang supports the ``format`` attribute, which indicates that the function -accepts a ``printf`` or ``scanf``-like format string and corresponding -arguments or a ``va_list`` that contains these arguments. - -Please see `GCC documentation about format attribute -<http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html>`_ to find details -about attribute syntax. - -Clang implements two kinds of checks with this attribute. - -#. Clang checks that the function with the ``format`` attribute is called with - a format string that uses format specifiers that are allowed, and that - arguments match the format string. This is the ``-Wformat`` warning, it is - on by default. - -#. Clang checks that the format string argument is a literal string. This is - the ``-Wformat-nonliteral`` warning, it is off by default. - - Clang implements this mostly the same way as GCC, but there is a difference - for functions that accept a ``va_list`` argument (for example, ``vprintf``). - GCC does not emit ``-Wformat-nonliteral`` warning for calls to such - functions. Clang does not warn if the format string comes from a function - parameter, where the function is annotated with a compatible attribute, - otherwise it warns. For example: - - .. code-block:: c - - __attribute__((__format__ (__scanf__, 1, 3))) - void foo(const char* s, char *buf, ...) { - va_list ap; - va_start(ap, buf); - - vprintf(s, ap); // warning: format string is not a string literal - } - - In this case we warn because ``s`` contains a format string for a - ``scanf``-like function, but it is passed to a ``printf``-like function. - - If the attribute is removed, clang still warns, because the format string is - not a string literal. - - Another example: - - .. code-block:: c - - __attribute__((__format__ (__printf__, 1, 3))) - void foo(const char* s, char *buf, ...) { - va_list ap; - va_start(ap, buf); - - vprintf(s, ap); // warning - } - - In this case Clang does not warn because the format string ``s`` and - the corresponding arguments are annotated. If the arguments are - incorrect, the caller of ``foo`` will receive a warning. - - -ifunc (gnu::ifunc) ------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -``__attribute__((ifunc("resolver")))`` is used to mark that the address of a declaration should be resolved at runtime by calling a resolver function. - -The symbol name of the resolver function is given in quotes. A function with this name (after mangling) must be defined in the current translation unit; it may be ``static``. The resolver function should take no arguments and return a pointer. - -The ``ifunc`` attribute may only be used on a function declaration. A function declaration with an ``ifunc`` attribute is considered to be a definition of the declared entity. The entity must not have weak linkage; for example, in C++, it cannot be applied to a declaration if a definition at that location would be considered inline. - -Not all targets support this attribute. ELF targets support this attribute when using binutils v2.20.1 or higher and glibc v2.11.1 or higher. Non-ELF targets currently do not support this attribute. - - -internal_linkage (clang::internal_linkage) ------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``internal_linkage`` attribute changes the linkage type of the declaration to internal. -This is similar to C-style ``static``, but can be used on classes and class methods. When applied to a class definition, -this attribute affects all methods and static data members of that class. -This can be used to contain the ABI of a C++ library by excluding unwanted class methods from the export tables. - - -interrupt ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Clang supports the GNU style ``__attribute__((interrupt("ARGUMENT")))`` attribute on -MIPS targets. This attribute may be attached to a function definition and instructs -the backend to generate appropriate function entry/exit code so that it can be used -directly as an interrupt service routine. - -By default, the compiler will produce a function prologue and epilogue suitable for -an interrupt service routine that handles an External Interrupt Controller (eic) -generated interrupt. This behaviour can be explicitly requested with the "eic" -argument. - -Otherwise, for use with vectored interrupt mode, the argument passed should be -of the form "vector=LEVEL" where LEVEL is one of the following values: -"sw0", "sw1", "hw0", "hw1", "hw2", "hw3", "hw4", "hw5". The compiler will -then set the interrupt mask to the corresponding level which will mask all -interrupts up to and including the argument. - -The semantics are as follows: - -- The prologue is modified so that the Exception Program Counter (EPC) and - Status coprocessor registers are saved to the stack. The interrupt mask is - set so that the function can only be interrupted by a higher priority - interrupt. The epilogue will restore the previous values of EPC and Status. - -- The prologue and epilogue are modified to save and restore all non-kernel - registers as necessary. - -- The FPU is disabled in the prologue, as the floating pointer registers are not - spilled to the stack. - -- The function return sequence is changed to use an exception return instruction. - -- The parameter sets the interrupt mask for the function corresponding to the - interrupt level specified. If no mask is specified the interrupt mask - defaults to "eic". - - -noalias -------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","X","", "" - -The ``noalias`` attribute indicates that the only memory accesses inside -function are loads and stores from objects pointed to by its pointer-typed -arguments, with arbitrary offsets. - - -noduplicate (clang::noduplicate) --------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``noduplicate`` attribute can be placed on function declarations to control -whether function calls to this function can be duplicated or not as a result of -optimizations. This is required for the implementation of functions with -certain special requirements, like the OpenCL "barrier" function, that might -need to be run concurrently by all the threads that are executing in lockstep -on the hardware. For example this attribute applied on the function -"nodupfunc" in the code below avoids that: - -.. code-block:: c - - void nodupfunc() __attribute__((noduplicate)); - // Setting it as a C++11 attribute is also valid - // void nodupfunc() [[clang::noduplicate]]; - void foo(); - void bar(); - - nodupfunc(); - if (a > n) { - foo(); - } else { - bar(); - } - -gets possibly modified by some optimizations into code similar to this: - -.. code-block:: c - - if (a > n) { - nodupfunc(); - foo(); - } else { - nodupfunc(); - bar(); - } - -where the call to "nodupfunc" is duplicated and sunk into the two branches -of the condition. - - -no_sanitize (clang::no_sanitize) --------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Use the ``no_sanitize`` attribute on a function declaration to specify -that a particular instrumentation or set of instrumentations should not be -applied to that function. The attribute takes a list of string literals, -which have the same meaning as values accepted by the ``-fno-sanitize=`` -flag. For example, ``__attribute__((no_sanitize("address", "thread")))`` -specifies that AddressSanitizer and ThreadSanitizer should not be applied -to the function. - -See :ref:`Controlling Code Generation <controlling-code-generation>` for a -full list of supported sanitizer flags. - - -no_sanitize_address (no_address_safety_analysis, gnu::no_address_safety_analysis, gnu::no_sanitize_address) ------------------------------------------------------------------------------------------------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -.. _langext-address_sanitizer: - -Use ``__attribute__((no_sanitize_address))`` on a function declaration to -specify that address safety instrumentation (e.g. AddressSanitizer) should -not be applied to that function. - - -no_sanitize_thread ------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -.. _langext-thread_sanitizer: - -Use ``__attribute__((no_sanitize_thread))`` on a function declaration to -specify that checks for data races on plain (non-atomic) memory accesses should -not be inserted by ThreadSanitizer. The function is still instrumented by the -tool to avoid false positives and provide meaningful stack traces. - - -no_sanitize_memory ------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -.. _langext-memory_sanitizer: - -Use ``__attribute__((no_sanitize_memory))`` on a function declaration to -specify that checks for uninitialized memory should not be inserted -(e.g. by MemorySanitizer). The function may still be instrumented by the tool -to avoid false positives in other places. - - -no_split_stack (gnu::no_split_stack) ------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``no_split_stack`` attribute disables the emission of the split stack -preamble for a particular function. It has no effect if ``-fsplit-stack`` -is not specified. - - -not_tail_called (clang::not_tail_called) ----------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``not_tail_called`` attribute prevents tail-call optimization on statically bound calls. It has no effect on indirect calls. Virtual functions, objective-c methods, and functions marked as ``always_inline`` cannot be marked as ``not_tail_called``. - -For example, it prevents tail-call optimization in the following case: - - .. code-block:: c - - int __attribute__((not_tail_called)) foo1(int); - - int foo2(int a) { - return foo1(a); // No tail-call optimization on direct calls. - } - -However, it doesn't prevent tail-call optimization in this case: - - .. code-block:: c - - int __attribute__((not_tail_called)) foo1(int); - - int foo2(int a) { - int (*fn)(int) = &foo1; - - // not_tail_called has no effect on an indirect call even if the call can be - // resolved at compile time. - return (*fn)(a); - } - -Marking virtual functions as ``not_tail_called`` is an error: - - .. code-block:: c++ - - class Base { - public: - // not_tail_called on a virtual function is an error. - [[clang::not_tail_called]] virtual int foo1(); - - virtual int foo2(); - - // Non-virtual functions can be marked ``not_tail_called``. - [[clang::not_tail_called]] int foo3(); - }; - - class Derived1 : public Base { - public: - int foo1() override; - - // not_tail_called on a virtual function is an error. - [[clang::not_tail_called]] int foo2() override; - }; - - -#pragma omp declare simd ------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","", "X" - -The `declare simd` construct can be applied to a function to enable the creation -of one or more versions that can process multiple arguments using SIMD -instructions from a single invocation in a SIMD loop. The `declare simd` -directive is a declarative directive. There may be multiple `declare simd` -directives for a function. The use of a `declare simd` construct on a function -enables the creation of SIMD versions of the associated function that can be -used to process multiple arguments from a single invocation from a SIMD loop -concurrently. -The syntax of the `declare simd` construct is as follows: - - .. code-block:: c - - #pragma omp declare simd [clause[[,] clause] ...] new-line - [#pragma omp declare simd [clause[[,] clause] ...] new-line] - [...] - function definition or declaration - -where clause is one of the following: - - .. code-block:: c - - simdlen(length) - linear(argument-list[:constant-linear-step]) - aligned(argument-list[:alignment]) - uniform(argument-list) - inbranch - notinbranch - - -#pragma omp declare target --------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","", "X" - -The `declare target` directive specifies that variables and functions are mapped -to a device for OpenMP offload mechanism. - -The syntax of the declare target directive is as follows: - - .. code-block:: c - - #pragma omp declare target new-line - declarations-definition-seq - #pragma omp end declare target new-line - - -objc_boxable ------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Structs and unions marked with the ``objc_boxable`` attribute can be used -with the Objective-C boxed expression syntax, ``@(...)``. - -**Usage**: ``__attribute__((objc_boxable))``. This attribute -can only be placed on a declaration of a trivially-copyable struct or union: - -.. code-block:: objc - - struct __attribute__((objc_boxable)) some_struct { - int i; - }; - union __attribute__((objc_boxable)) some_union { - int i; - float f; - }; - typedef struct __attribute__((objc_boxable)) _some_struct some_struct; - - // ... - - some_struct ss; - NSValue *boxed = @(ss); - - -objc_method_family ------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Many methods in Objective-C have conventional meanings determined by their -selectors. It is sometimes useful to be able to mark a method as having a -particular conventional meaning despite not having the right selector, or as -not having the conventional meaning that its selector would suggest. For these -use cases, we provide an attribute to specifically describe the "method family" -that a method belongs to. - -**Usage**: ``__attribute__((objc_method_family(X)))``, where ``X`` is one of -``none``, ``alloc``, ``copy``, ``init``, ``mutableCopy``, or ``new``. This -attribute can only be placed at the end of a method declaration: - -.. code-block:: objc - - - (NSString *)initMyStringValue __attribute__((objc_method_family(none))); - -Users who do not wish to change the conventional meaning of a method, and who -merely want to document its non-standard retain and release semantics, should -use the retaining behavior attributes (``ns_returns_retained``, -``ns_returns_not_retained``, etc). - -Query for this feature with ``__has_attribute(objc_method_family)``. - - -objc_requires_super -------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Some Objective-C classes allow a subclass to override a particular method in a -parent class but expect that the overriding method also calls the overridden -method in the parent class. For these cases, we provide an attribute to -designate that a method requires a "call to ``super``" in the overriding -method in the subclass. - -**Usage**: ``__attribute__((objc_requires_super))``. This attribute can only -be placed at the end of a method declaration: - -.. code-block:: objc - - - (void)foo __attribute__((objc_requires_super)); - -This attribute can only be applied the method declarations within a class, and -not a protocol. Currently this attribute does not enforce any placement of -where the call occurs in the overriding method (such as in the case of -``-dealloc`` where the call must appear at the end). It checks only that it -exists. - -Note that on both OS X and iOS that the Foundation framework provides a -convenience macro ``NS_REQUIRES_SUPER`` that provides syntactic sugar for this -attribute: - -.. code-block:: objc - - - (void)foo NS_REQUIRES_SUPER; - -This macro is conditionally defined depending on the compiler's support for -this attribute. If the compiler does not support the attribute the macro -expands to nothing. - -Operationally, when a method has this annotation the compiler will warn if the -implementation of an override in a subclass does not call super. For example: - -.. code-block:: objc - - warning: method possibly missing a [super AnnotMeth] call - - (void) AnnotMeth{}; - ^ - - -objc_runtime_name ------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -By default, the Objective-C interface or protocol identifier is used -in the metadata name for that object. The `objc_runtime_name` -attribute allows annotated interfaces or protocols to use the -specified string argument in the object's metadata name instead of the -default name. - -**Usage**: ``__attribute__((objc_runtime_name("MyLocalName")))``. This attribute -can only be placed before an @protocol or @interface declaration: - -.. code-block:: objc - - __attribute__((objc_runtime_name("MyLocalName"))) - @interface Message - @end - - -objc_runtime_visible --------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -This attribute specifies that the Objective-C class to which it applies is visible to the Objective-C runtime but not to the linker. Classes annotated with this attribute cannot be subclassed and cannot have categories defined for them. - - -optnone (clang::optnone) ------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``optnone`` attribute suppresses essentially all optimizations -on a function or method, regardless of the optimization level applied to -the compilation unit as a whole. This is particularly useful when you -need to debug a particular function, but it is infeasible to build the -entire application without optimization. Avoiding optimization on the -specified function can improve the quality of the debugging information -for that function. - -This attribute is incompatible with the ``always_inline`` and ``minsize`` -attributes. - - -overloadable ------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Clang provides support for C++ function overloading in C. Function overloading -in C is introduced using the ``overloadable`` attribute. For example, one -might provide several overloaded versions of a ``tgsin`` function that invokes -the appropriate standard function computing the sine of a value with ``float``, -``double``, or ``long double`` precision: - -.. code-block:: c - - #include <math.h> - float __attribute__((overloadable)) tgsin(float x) { return sinf(x); } - double __attribute__((overloadable)) tgsin(double x) { return sin(x); } - long double __attribute__((overloadable)) tgsin(long double x) { return sinl(x); } - -Given these declarations, one can call ``tgsin`` with a ``float`` value to -receive a ``float`` result, with a ``double`` to receive a ``double`` result, -etc. Function overloading in C follows the rules of C++ function overloading -to pick the best overload given the call arguments, with a few C-specific -semantics: - -* Conversion from ``float`` or ``double`` to ``long double`` is ranked as a - floating-point promotion (per C99) rather than as a floating-point conversion - (as in C++). - -* A conversion from a pointer of type ``T*`` to a pointer of type ``U*`` is - considered a pointer conversion (with conversion rank) if ``T`` and ``U`` are - compatible types. - -* A conversion from type ``T`` to a value of type ``U`` is permitted if ``T`` - and ``U`` are compatible types. This conversion is given "conversion" rank. - -* If no viable candidates are otherwise available, we allow a conversion from a - pointer of type ``T*`` to a pointer of type ``U*``, where ``T`` and ``U`` are - incompatible. This conversion is ranked below all other types of conversions. - Please note: ``U`` lacking qualifiers that are present on ``T`` is sufficient - for ``T`` and ``U`` to be incompatible. - -The declaration of ``overloadable`` functions is restricted to function -declarations and definitions. Most importantly, if any function with a given -name is given the ``overloadable`` attribute, then all function declarations -and definitions with that name (and in that scope) must have the -``overloadable`` attribute. This rule even applies to redeclarations of -functions whose original declaration had the ``overloadable`` attribute, e.g., - -.. code-block:: c - - int f(int) __attribute__((overloadable)); - float f(float); // error: declaration of "f" must have the "overloadable" attribute - - int g(int) __attribute__((overloadable)); - int g(int) { } // error: redeclaration of "g" must also have the "overloadable" attribute - -Functions marked ``overloadable`` must have prototypes. Therefore, the -following code is ill-formed: - -.. code-block:: c - - int h() __attribute__((overloadable)); // error: h does not have a prototype - -However, ``overloadable`` functions are allowed to use a ellipsis even if there -are no named parameters (as is permitted in C++). This feature is particularly -useful when combined with the ``unavailable`` attribute: - -.. code-block:: c++ - - void honeypot(...) __attribute__((overloadable, unavailable)); // calling me is an error - -Functions declared with the ``overloadable`` attribute have their names mangled -according to the same rules as C++ function names. For example, the three -``tgsin`` functions in our motivating example get the mangled names -``_Z5tgsinf``, ``_Z5tgsind``, and ``_Z5tgsine``, respectively. There are two -caveats to this use of name mangling: - -* Future versions of Clang may change the name mangling of functions overloaded - in C, so you should not depend on an specific mangling. To be completely - safe, we strongly urge the use of ``static inline`` with ``overloadable`` - functions. - -* The ``overloadable`` attribute has almost no meaning when used in C++, - because names will already be mangled and functions are already overloadable. - However, when an ``overloadable`` function occurs within an ``extern "C"`` - linkage specification, it's name *will* be mangled in the same way as it - would in C. - -Query for this feature with ``__has_extension(attribute_overloadable)``. - - -release_capability (release_shared_capability, clang::release_capability, clang::release_shared_capability) ------------------------------------------------------------------------------------------------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Marks a function as releasing a capability. - - -kernel ------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -``__attribute__((kernel))`` is used to mark a ``kernel`` function in -RenderScript. - -In RenderScript, ``kernel`` functions are used to express data-parallel -computations. The RenderScript runtime efficiently parallelizes ``kernel`` -functions to run on computational resources such as multi-core CPUs and GPUs. -See the RenderScript_ documentation for more information. - -.. _RenderScript: https://developer.android.com/guide/topics/renderscript/compute.html - - -target (gnu::target) --------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Clang supports the GNU style ``__attribute__((target("OPTIONS")))`` attribute. -This attribute may be attached to a function definition and instructs -the backend to use different code generation options than were passed on the -command line. - -The current set of options correspond to the existing "subtarget features" for -the target with or without a "-mno-" in front corresponding to the absence -of the feature, as well as ``arch="CPU"`` which will change the default "CPU" -for the function. - -Example "subtarget features" from the x86 backend include: "mmx", "sse", "sse4.2", -"avx", "xop" and largely correspond to the machine specific options handled by -the front end. - - -try_acquire_capability (try_acquire_shared_capability, clang::try_acquire_capability, clang::try_acquire_shared_capability) ---------------------------------------------------------------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Marks a function that attempts to acquire a capability. This function may fail to -actually acquire the capability; they accept a Boolean value determining -whether acquiring the capability means success (true), or failing to acquire -the capability means success (false). - - -nodiscard, warn_unused_result, clang::warn_unused_result, gnu::warn_unused_result ---------------------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -Clang supports the ability to diagnose when the results of a function call -expression are discarded under suspicious circumstances. A diagnostic is -generated when a function or its return type is marked with ``[[nodiscard]]`` -(or ``__attribute__((warn_unused_result))``) and the function call appears as a -potentially-evaluated discarded-value expression that is not explicitly cast to -`void`. - -.. code-block: c++ - struct [[nodiscard]] error_info { /*...*/ }; - error_info enable_missile_safety_mode(); - - void launch_missiles(); - void test_missiles() { - enable_missile_safety_mode(); // diagnoses - launch_missiles(); - } - error_info &foo(); - void f() { foo(); } // Does not diagnose, error_info is a reference. - - -xray_always_instrument (clang::xray_always_instrument), xray_never_instrument (clang::xray_never_instrument) ------------------------------------------------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -``__attribute__((xray_always_instrument))`` or ``[[clang::xray_always_instrument]]`` is used to mark member functions (in C++), methods (in Objective C), and free functions (in C, C++, and Objective C) to be instrumented with XRay. This will cause the function to always have space at the beginning and exit points to allow for runtime patching. - -Conversely, ``__attribute__((xray_never_instrument))`` or ``[[clang::xray_never_instrument]]`` will inhibit the insertion of these instrumentation points. - -If a function has neither of these attributes, they become subject to the XRay heuristics used to determine whether a function should be instrumented or otherwise. - - -Variable Attributes -=================== - - -dllexport (gnu::dllexport) --------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","X","", "" - -The ``__declspec(dllexport)`` attribute declares a variable, function, or -Objective-C interface to be exported from the module. It is available under the -``-fdeclspec`` flag for compatibility with various compilers. The primary use -is for COFF object files which explicitly specify what interfaces are available -for external use. See the dllexport_ documentation on MSDN for more -information. - -.. _dllexport: https://msdn.microsoft.com/en-us/library/3y1sfaz2.aspx - - -dllimport (gnu::dllimport) --------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","X","", "" - -The ``__declspec(dllimport)`` attribute declares a variable, function, or -Objective-C interface to be imported from an external module. It is available -under the ``-fdeclspec`` flag for compatibility with various compilers. The -primary use is for COFF object files which explicitly specify what interfaces -are imported from external modules. See the dllimport_ documentation on MSDN -for more information. - -.. _dllimport: https://msdn.microsoft.com/en-us/library/3y1sfaz2.aspx - - -init_seg --------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","", "X" - -The attribute applied by ``pragma init_seg()`` controls the section into -which global initialization function pointers are emitted. It is only -available with ``-fms-extensions``. Typically, this function pointer is -emitted into ``.CRT$XCU`` on Windows. The user can change the order of -initialization by using a different section name with the same -``.CRT$XC`` prefix and a suffix that sorts lexicographically before or -after the standard ``.CRT$XCU`` sections. See the init_seg_ -documentation on MSDN for more information. - -.. _init_seg: http://msdn.microsoft.com/en-us/library/7977wcck(v=vs.110).aspx - - -nodebug (gnu::nodebug) ----------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``nodebug`` attribute allows you to suppress debugging information for a -function or method, or for a variable that is not a parameter or a non-static -data member. - - -nosvm ------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -OpenCL 2.0 supports the optional ``__attribute__((nosvm))`` qualifier for -pointer variable. It informs the compiler that the pointer does not refer -to a shared virtual memory region. See OpenCL v2.0 s6.7.2 for details. - -Since it is not widely used and has been removed from OpenCL 2.1, it is ignored -by Clang. - - -pass_object_size ----------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -.. Note:: The mangling of functions with parameters that are annotated with - ``pass_object_size`` is subject to change. You can get around this by - using ``__asm__("foo")`` to explicitly name your functions, thus preserving - your ABI; also, non-overloadable C functions with ``pass_object_size`` are - not mangled. - -The ``pass_object_size(Type)`` attribute can be placed on function parameters to -instruct clang to call ``__builtin_object_size(param, Type)`` at each callsite -of said function, and implicitly pass the result of this call in as an invisible -argument of type ``size_t`` directly after the parameter annotated with -``pass_object_size``. Clang will also replace any calls to -``__builtin_object_size(param, Type)`` in the function by said implicit -parameter. - -Example usage: - -.. code-block:: c - - int bzero1(char *const p __attribute__((pass_object_size(0)))) - __attribute__((noinline)) { - int i = 0; - for (/**/; i < (int)__builtin_object_size(p, 0); ++i) { - p[i] = 0; - } - return i; - } - - int main() { - char chars[100]; - int n = bzero1(&chars[0]); - assert(n == sizeof(chars)); - return 0; - } - -If successfully evaluating ``__builtin_object_size(param, Type)`` at the -callsite is not possible, then the "failed" value is passed in. So, using the -definition of ``bzero1`` from above, the following code would exit cleanly: - -.. code-block:: c - - int main2(int argc, char *argv[]) { - int n = bzero1(argv); - assert(n == -1); - return 0; - } - -``pass_object_size`` plays a part in overload resolution. If two overload -candidates are otherwise equally good, then the overload with one or more -parameters with ``pass_object_size`` is preferred. This implies that the choice -between two identical overloads both with ``pass_object_size`` on one or more -parameters will always be ambiguous; for this reason, having two such overloads -is illegal. For example: - -.. code-block:: c++ - - #define PS(N) __attribute__((pass_object_size(N))) - // OK - void Foo(char *a, char *b); // Overload A - // OK -- overload A has no parameters with pass_object_size. - void Foo(char *a PS(0), char *b PS(0)); // Overload B - // Error -- Same signature (sans pass_object_size) as overload B, and both - // overloads have one or more parameters with the pass_object_size attribute. - void Foo(void *a PS(0), void *b); - - // OK - void Bar(void *a PS(0)); // Overload C - // OK - void Bar(char *c PS(1)); // Overload D - - void main() { - char known[10], *unknown; - Foo(unknown, unknown); // Calls overload B - Foo(known, unknown); // Calls overload B - Foo(unknown, known); // Calls overload B - Foo(known, known); // Calls overload B - - Bar(known); // Calls overload D - Bar(unknown); // Calls overload D - } - -Currently, ``pass_object_size`` is a bit restricted in terms of its usage: - -* Only one use of ``pass_object_size`` is allowed per parameter. - -* It is an error to take the address of a function with ``pass_object_size`` on - any of its parameters. If you wish to do this, you can create an overload - without ``pass_object_size`` on any parameters. - -* It is an error to apply the ``pass_object_size`` attribute to parameters that - are not pointers. Additionally, any parameter that ``pass_object_size`` is - applied to must be marked ``const`` at its function's definition. - - -require_constant_initialization (clang::require_constant_initialization) ------------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -This attribute specifies that the variable to which it is attached is intended -to have a `constant initializer <http://en.cppreference.com/w/cpp/language/constant_initialization>`_ -according to the rules of [basic.start.static]. The variable is required to -have static or thread storage duration. If the initialization of the variable -is not a constant initializer an error will be produced. This attribute may -only be used in C++. - -Note that in C++03 strict constant expression checking is not done. Instead -the attribute reports if Clang can emit the variable as a constant, even if it's -not technically a 'constant initializer'. This behavior is non-portable. - -Static storage duration variables with constant initializers avoid hard-to-find -bugs caused by the indeterminate order of dynamic initialization. They can also -be safely used during dynamic initialization across translation units. - -This attribute acts as a compile time assertion that the requirements -for constant initialization have been met. Since these requirements change -between dialects and have subtle pitfalls it's important to fail fast instead -of silently falling back on dynamic initialization. - -.. code-block:: c++ - - // -std=c++14 - #define SAFE_STATIC [[clang::require_constant_initialization]] - struct T { - constexpr T(int) {} - ~T(); // non-trivial - }; - SAFE_STATIC T x = {42}; // Initialization OK. Doesn't check destructor. - SAFE_STATIC T y = 42; // error: variable does not have a constant initializer - // copy initialization is not a constant expression on a non-literal type. - - -section (gnu::section, __declspec(allocate)) --------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","X","", "" - -The ``section`` attribute allows you to specify a specific section a -global variable or function should be in after translation. - - -swiftcall (gnu::swiftcall) --------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``swiftcall`` attribute indicates that a function should be called -using the Swift calling convention for a function or function pointer. - -The lowering for the Swift calling convention, as described by the Swift -ABI documentation, occurs in multiple phases. The first, "high-level" -phase breaks down the formal parameters and results into innately direct -and indirect components, adds implicit paraameters for the generic -signature, and assigns the context and error ABI treatments to parameters -where applicable. The second phase breaks down the direct parameters -and results from the first phase and assigns them to registers or the -stack. The ``swiftcall`` convention only handles this second phase of -lowering; the C function type must accurately reflect the results -of the first phase, as follows: - -- Results classified as indirect by high-level lowering should be - represented as parameters with the ``swift_indirect_result`` attribute. - -- Results classified as direct by high-level lowering should be represented - as follows: - - - First, remove any empty direct results. - - - If there are no direct results, the C result type should be ``void``. - - - If there is one direct result, the C result type should be a type with - the exact layout of that result type. - - - If there are a multiple direct results, the C result type should be - a struct type with the exact layout of a tuple of those results. - -- Parameters classified as indirect by high-level lowering should be - represented as parameters of pointer type. - -- Parameters classified as direct by high-level lowering should be - omitted if they are empty types; otherwise, they should be represented - as a parameter type with a layout exactly matching the layout of the - Swift parameter type. - -- The context parameter, if present, should be represented as a trailing - parameter with the ``swift_context`` attribute. - -- The error result parameter, if present, should be represented as a - trailing parameter (always following a context parameter) with the - ``swift_error_result`` attribute. - -``swiftcall`` does not support variadic arguments or unprototyped functions. - -The parameter ABI treatment attributes are aspects of the function type. -A function type which which applies an ABI treatment attribute to a -parameter is a different type from an otherwise-identical function type -that does not. A single parameter may not have multiple ABI treatment -attributes. - -Support for this feature is target-dependent, although it should be -supported on every target that Swift supports. Query for this support -with ``__has_attribute(swiftcall)``. This implies support for the -``swift_context``, ``swift_error_result``, and ``swift_indirect_result`` -attributes. - - -swift_context (gnu::swift_context) ----------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``swift_context`` attribute marks a parameter of a ``swiftcall`` -function as having the special context-parameter ABI treatment. - -This treatment generally passes the context value in a special register -which is normally callee-preserved. - -A ``swift_context`` parameter must either be the last parameter or must be -followed by a ``swift_error_result`` parameter (which itself must always be -the last parameter). - -A context parameter must have pointer or reference type. - - -swift_error_result (gnu::swift_error_result) --------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``swift_error_result`` attribute marks a parameter of a ``swiftcall`` -function as having the special error-result ABI treatment. - -This treatment generally passes the underlying error value in and out of -the function through a special register which is normally callee-preserved. -This is modeled in C by pretending that the register is addressable memory: - -- The caller appears to pass the address of a variable of pointer type. - The current value of this variable is copied into the register before - the call; if the call returns normally, the value is copied back into the - variable. - -- The callee appears to receive the address of a variable. This address - is actually a hidden location in its own stack, initialized with the - value of the register upon entry. When the function returns normally, - the value in that hidden location is written back to the register. - -A ``swift_error_result`` parameter must be the last parameter, and it must be -preceded by a ``swift_context`` parameter. - -A ``swift_error_result`` parameter must have type ``T**`` or ``T*&`` for some -type T. Note that no qualifiers are permitted on the intermediate level. - -It is undefined behavior if the caller does not pass a pointer or -reference to a valid object. - -The standard convention is that the error value itself (that is, the -value stored in the apparent argument) will be null upon function entry, -but this is not enforced by the ABI. - - -swift_indirect_result (gnu::swift_indirect_result) --------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``swift_indirect_result`` attribute marks a parameter of a ``swiftcall`` -function as having the special indirect-result ABI treatment. - -This treatment gives the parameter the target's normal indirect-result -ABI treatment, which may involve passing it differently from an ordinary -parameter. However, only the first indirect result will receive this -treatment. Furthermore, low-level lowering may decide that a direct result -must be returned indirectly; if so, this will take priority over the -``swift_indirect_result`` parameters. - -A ``swift_indirect_result`` parameter must either be the first parameter or -follow another ``swift_indirect_result`` parameter. - -A ``swift_indirect_result`` parameter must have type ``T*`` or ``T&`` for -some object type ``T``. If ``T`` is a complete type at the point of -definition of a function, it is undefined behavior if the argument -value does not point to storage of adequate size and alignment for a -value of type ``T``. - -Making indirect results explicit in the signature allows C functions to -directly construct objects into them without relying on language -optimizations like C++'s named return value optimization (NRVO). - - -tls_model (gnu::tls_model) --------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``tls_model`` attribute allows you to specify which thread-local storage -model to use. It accepts the following strings: - -* global-dynamic -* local-dynamic -* initial-exec -* local-exec - -TLS models are mutually exclusive. - - -thread ------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","X","", "" - -The ``__declspec(thread)`` attribute declares a variable with thread local -storage. It is available under the ``-fms-extensions`` flag for MSVC -compatibility. See the documentation for `__declspec(thread)`_ on MSDN. - -.. _`__declspec(thread)`: http://msdn.microsoft.com/en-us/library/9w1sdazb.aspx - -In Clang, ``__declspec(thread)`` is generally equivalent in functionality to the -GNU ``__thread`` keyword. The variable must not have a destructor and must have -a constant initializer, if any. The attribute only applies to variables -declared with static storage duration, such as globals, class static data -members, and static locals. - - -maybe_unused, unused, gnu::unused ---------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -When passing the ``-Wunused`` flag to Clang, entities that are unused by the -program may be diagnosed. The ``[[maybe_unused]]`` (or -``__attribute__((unused))``) attribute can be used to silence such diagnostics -when the entity cannot be removed. For instance, a local variable may exist -solely for use in an ``assert()`` statement, which makes the local variable -unused when ``NDEBUG`` is defined. - -The attribute may be applied to the declaration of a class, a typedef, a -variable, a function or method, a function parameter, an enumeration, an -enumerator, a non-static data member, or a label. - -.. code-block: c++ - #include <cassert> - - [[maybe_unused]] void f([[maybe_unused]] bool thing1, - [[maybe_unused]] bool thing2) { - [[maybe_unused]] bool b = thing1 && thing2; - assert(b); - } - - -Type Attributes -=============== - - -align_value ------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -The align_value attribute can be added to the typedef of a pointer type or the -declaration of a variable of pointer or reference type. It specifies that the -pointer will point to, or the reference will bind to, only objects with at -least the provided alignment. This alignment value must be some positive power -of 2. - - .. code-block:: c - - typedef double * aligned_double_ptr __attribute__((align_value(64))); - void foo(double & x __attribute__((align_value(128)), - aligned_double_ptr y) { ... } - -If the pointer value does not have the specified alignment at runtime, the -behavior of the program is undefined. - - -empty_bases ------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","X","", "" - -The empty_bases attribute permits the compiler to utilize the -empty-base-optimization more frequently. -This attribute only applies to struct, class, and union types. -It is only supported when using the Microsoft C++ ABI. - - -flag_enum ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -This attribute can be added to an enumerator to signal to the compiler that it -is intended to be used as a flag type. This will cause the compiler to assume -that the range of the type includes all of the values that you can get by -manipulating bits of the enumerator when issuing warnings. - - -lto_visibility_public (clang::lto_visibility_public) ----------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","X","","", "" - -See :doc:`LTOVisibility`. - - -layout_version --------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","X","", "" - -The layout_version attribute requests that the compiler utilize the class -layout rules of a particular compiler version. -This attribute only applies to struct, class, and union types. -It is only supported when using the Microsoft C++ ABI. - - -__single_inhertiance, __multiple_inheritance, __virtual_inheritance -------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -This collection of keywords is enabled under ``-fms-extensions`` and controls -the pointer-to-member representation used on ``*-*-win32`` targets. - -The ``*-*-win32`` targets utilize a pointer-to-member representation which -varies in size and alignment depending on the definition of the underlying -class. - -However, this is problematic when a forward declaration is only available and -no definition has been made yet. In such cases, Clang is forced to utilize the -most general representation that is available to it. - -These keywords make it possible to use a pointer-to-member representation other -than the most general one regardless of whether or not the definition will ever -be present in the current translation unit. - -This family of keywords belong between the ``class-key`` and ``class-name``: - -.. code-block:: c++ - - struct __single_inheritance S; - int S::*i; - struct S {}; - -This keyword can be applied to class templates but only has an effect when used -on full specializations: - -.. code-block:: c++ - - template <typename T, typename U> struct __single_inheritance A; // warning: inheritance model ignored on primary template - template <typename T> struct __multiple_inheritance A<T, T>; // warning: inheritance model ignored on partial specialization - template <> struct __single_inheritance A<int, float>; - -Note that choosing an inheritance model less general than strictly necessary is -an error: - -.. code-block:: c++ - - struct __multiple_inheritance S; // error: inheritance model does not match definition - int S::*i; - struct S {}; - - -novtable --------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","X","", "" - -This attribute can be added to a class declaration or definition to signal to -the compiler that constructors and destructors will not reference the virtual -function table. It is only supported when using the Microsoft C++ ABI. - - -objc_subclassing_restricted ---------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -This attribute can be added to an Objective-C ``@interface`` declaration to -ensure that this class cannot be subclassed. - - -transparent_union (gnu::transparent_union) ------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -This attribute can be applied to a union to change the behaviour of calls to -functions that have an argument with a transparent union type. The compiler -behaviour is changed in the following manner: - -- A value whose type is any member of the transparent union can be passed as an - argument without the need to cast that value. - -- The argument is passed to the function using the calling convention of the - first member of the transparent union. Consequently, all the members of the - transparent union should have the same calling convention as its first member. - -Transparent unions are not supported in C++. - - -Statement Attributes -==================== - - -fallthrough, clang::fallthrough -------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","X","","", "" - -The ``fallthrough`` (or ``clang::fallthrough``) attribute is used -to annotate intentional fall-through -between switch labels. It can only be applied to a null statement placed at a -point of execution between any statement and the next switch label. It is -common to mark these places with a specific comment, but this attribute is -meant to replace comments with a more strict annotation, which can be checked -by the compiler. This attribute doesn't change semantics of the code and can -be used wherever an intended fall-through occurs. It is designed to mimic -control-flow statements like ``break;``, so it can be placed in most places -where ``break;`` can, but only if there are no statements on the execution path -between it and the next switch label. - -By default, Clang does not warn on unannotated fallthrough from one ``switch`` -case to another. Diagnostics on fallthrough without a corresponding annotation -can be enabled with the ``-Wimplicit-fallthrough`` argument. - -Here is an example: - -.. code-block:: c++ - - // compile with -Wimplicit-fallthrough - switch (n) { - case 22: - case 33: // no warning: no statements between case labels - f(); - case 44: // warning: unannotated fall-through - g(); - [[clang::fallthrough]]; - case 55: // no warning - if (x) { - h(); - break; - } - else { - i(); - [[clang::fallthrough]]; - } - case 66: // no warning - p(); - [[clang::fallthrough]]; // warning: fallthrough annotation does not - // directly precede case label - q(); - case 77: // warning: unannotated fall-through - r(); - } - - -#pragma clang loop ------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","", "X" - -The ``#pragma clang loop`` directive allows loop optimization hints to be -specified for the subsequent loop. The directive allows vectorization, -interleaving, and unrolling to be enabled or disabled. Vector width as well -as interleave and unrolling count can be manually specified. See -`language extensions -<http://clang.llvm.org/docs/LanguageExtensions.html#extensions-for-loop-hint-optimizations>`_ -for details. - - -#pragma unroll, #pragma nounroll --------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","", "X" - -Loop unrolling optimization hints can be specified with ``#pragma unroll`` and -``#pragma nounroll``. The pragma is placed immediately before a for, while, -do-while, or c++11 range-based for loop. - -Specifying ``#pragma unroll`` without a parameter directs the loop unroller to -attempt to fully unroll the loop if the trip count is known at compile time and -attempt to partially unroll the loop if the trip count is not known at compile -time: - -.. code-block:: c++ - - #pragma unroll - for (...) { - ... - } - -Specifying the optional parameter, ``#pragma unroll _value_``, directs the -unroller to unroll the loop ``_value_`` times. The parameter may optionally be -enclosed in parentheses: - -.. code-block:: c++ - - #pragma unroll 16 - for (...) { - ... - } - - #pragma unroll(16) - for (...) { - ... - } - -Specifying ``#pragma nounroll`` indicates that the loop should not be unrolled: - -.. code-block:: c++ - - #pragma nounroll - for (...) { - ... - } - -``#pragma unroll`` and ``#pragma unroll _value_`` have identical semantics to -``#pragma clang loop unroll(full)`` and -``#pragma clang loop unroll_count(_value_)`` respectively. ``#pragma nounroll`` -is equivalent to ``#pragma clang loop unroll(disable)``. See -`language extensions -<http://clang.llvm.org/docs/LanguageExtensions.html#extensions-for-loop-hint-optimizations>`_ -for further details including limitations of the unroll hints. - - -__read_only, __write_only, __read_write (read_only, write_only, read_write) ---------------------------------------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The access qualifiers must be used with image object arguments or pipe arguments -to declare if they are being read or written by a kernel or function. - -The read_only/__read_only, write_only/__write_only and read_write/__read_write -names are reserved for use as access qualifiers and shall not be used otherwise. - -.. code-block:: c - - kernel void - foo (read_only image2d_t imageA, - write_only image2d_t imageB) { - ... - } - -In the above example imageA is a read-only 2D image object, and imageB is a -write-only 2D image object. - -The read_write (or __read_write) qualifier can not be used with pipe. - -More details can be found in the OpenCL C language Spec v2.0, Section 6.6. - - -__attribute__((opencl_unroll_hint)) ------------------------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -The opencl_unroll_hint attribute qualifier can be used to specify that a loop -(for, while and do loops) can be unrolled. This attribute qualifier can be -used to specify full unrolling or partial unrolling by a specified amount. -This is a compiler hint and the compiler may ignore this directive. See -`OpenCL v2.0 <https://www.khronos.org/registry/cl/specs/opencl-2.0.pdf>`_ -s6.11.5 for details. - - -Type Safety Checking -==================== -Clang supports additional attributes to enable checking type safety properties -that can't be enforced by the C type system. To see warnings produced by these -checks, ensure that -Wtype-safety is enabled. Use cases include: - -* MPI library implementations, where these attributes enable checking that - the buffer type matches the passed ``MPI_Datatype``; -* for HDF5 library there is a similar use case to MPI; -* checking types of variadic functions' arguments for functions like - ``fcntl()`` and ``ioctl()``. - -You can detect support for these attributes with ``__has_attribute()``. For -example: - -.. code-block:: c++ - - #if defined(__has_attribute) - # if __has_attribute(argument_with_type_tag) && \ - __has_attribute(pointer_with_type_tag) && \ - __has_attribute(type_tag_for_datatype) - # define ATTR_MPI_PWT(buffer_idx, type_idx) __attribute__((pointer_with_type_tag(mpi,buffer_idx,type_idx))) - /* ... other macros ... */ - # endif - #endif - - #if !defined(ATTR_MPI_PWT) - # define ATTR_MPI_PWT(buffer_idx, type_idx) - #endif - - int MPI_Send(void *buf, int count, MPI_Datatype datatype /*, other args omitted */) - ATTR_MPI_PWT(1,3); - -argument_with_type_tag ----------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Use ``__attribute__((argument_with_type_tag(arg_kind, arg_idx, -type_tag_idx)))`` on a function declaration to specify that the function -accepts a type tag that determines the type of some other argument. - -This attribute is primarily useful for checking arguments of variadic functions -(``pointer_with_type_tag`` can be used in most non-variadic cases). - -In the attribute prototype above: - * ``arg_kind`` is an identifier that should be used when annotating all - applicable type tags. - * ``arg_idx`` provides the position of a function argument. The expected type of - this function argument will be determined by the function argument specified - by ``type_tag_idx``. In the code example below, "3" means that the type of the - function's third argument will be determined by ``type_tag_idx``. - * ``type_tag_idx`` provides the position of a function argument. This function - argument will be a type tag. The type tag will determine the expected type of - the argument specified by ``arg_idx``. In the code example below, "2" means - that the type tag associated with the function's second argument should agree - with the type of the argument specified by ``arg_idx``. - -For example: - -.. code-block:: c++ - - int fcntl(int fd, int cmd, ...) - __attribute__(( argument_with_type_tag(fcntl,3,2) )); - // The function's second argument will be a type tag; this type tag will - // determine the expected type of the function's third argument. - - -pointer_with_type_tag ---------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Use ``__attribute__((pointer_with_type_tag(ptr_kind, ptr_idx, type_tag_idx)))`` -on a function declaration to specify that the function accepts a type tag that -determines the pointee type of some other pointer argument. - -In the attribute prototype above: - * ``ptr_kind`` is an identifier that should be used when annotating all - applicable type tags. - * ``ptr_idx`` provides the position of a function argument; this function - argument will have a pointer type. The expected pointee type of this pointer - type will be determined by the function argument specified by - ``type_tag_idx``. In the code example below, "1" means that the pointee type - of the function's first argument will be determined by ``type_tag_idx``. - * ``type_tag_idx`` provides the position of a function argument; this function - argument will be a type tag. The type tag will determine the expected pointee - type of the pointer argument specified by ``ptr_idx``. In the code example - below, "3" means that the type tag associated with the function's third - argument should agree with the pointee type of the pointer argument specified - by ``ptr_idx``. - -For example: - -.. code-block:: c++ - - typedef int MPI_Datatype; - int MPI_Send(void *buf, int count, MPI_Datatype datatype /*, other args omitted */) - __attribute__(( pointer_with_type_tag(mpi,1,3) )); - // The function's 3rd argument will be a type tag; this type tag will - // determine the expected pointee type of the function's 1st argument. - - -type_tag_for_datatype ---------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -When declaring a variable, use -``__attribute__((type_tag_for_datatype(kind, type)))`` to create a type tag that -is tied to the ``type`` argument given to the attribute. - -In the attribute prototype above: - * ``kind`` is an identifier that should be used when annotating all applicable - type tags. - * ``type`` indicates the name of the type. - -Clang supports annotating type tags of two forms. - - * **Type tag that is a reference to a declared identifier.** - Use ``__attribute__((type_tag_for_datatype(kind, type)))`` when declaring that - identifier: - - .. code-block:: c++ - - typedef int MPI_Datatype; - extern struct mpi_datatype mpi_datatype_int - __attribute__(( type_tag_for_datatype(mpi,int) )); - #define MPI_INT ((MPI_Datatype) &mpi_datatype_int) - // &mpi_datatype_int is a type tag. It is tied to type "int". - - * **Type tag that is an integral literal.** - Declare a ``static const`` variable with an initializer value and attach - ``__attribute__((type_tag_for_datatype(kind, type)))`` on that declaration: - - .. code-block:: c++ - - typedef int MPI_Datatype; - static const MPI_Datatype mpi_datatype_int - __attribute__(( type_tag_for_datatype(mpi,int) )) = 42; - #define MPI_INT ((MPI_Datatype) 42) - // The number 42 is a type tag. It is tied to type "int". - - -The ``type_tag_for_datatype`` attribute also accepts an optional third argument -that determines how the type of the function argument specified by either -``arg_idx`` or ``ptr_idx`` is compared against the type associated with the type -tag. (Recall that for the ``argument_with_type_tag`` attribute, the type of the -function argument specified by ``arg_idx`` is compared against the type -associated with the type tag. Also recall that for the ``pointer_with_type_tag`` -attribute, the pointee type of the function argument specified by ``ptr_idx`` is -compared against the type associated with the type tag.) There are two supported -values for this optional third argument: - - * ``layout_compatible`` will cause types to be compared according to - layout-compatibility rules (In C++11 [class.mem] p 17, 18, see the - layout-compatibility rules for two standard-layout struct types and for two - standard-layout union types). This is useful when creating a type tag - associated with a struct or union type. For example: - - .. code-block:: c++ - - /* In mpi.h */ - typedef int MPI_Datatype; - struct internal_mpi_double_int { double d; int i; }; - extern struct mpi_datatype mpi_datatype_double_int - __attribute__(( type_tag_for_datatype(mpi, - struct internal_mpi_double_int, layout_compatible) )); - - #define MPI_DOUBLE_INT ((MPI_Datatype) &mpi_datatype_double_int) - - int MPI_Send(void *buf, int count, MPI_Datatype datatype, ...) - __attribute__(( pointer_with_type_tag(mpi,1,3) )); - - /* In user code */ - struct my_pair { double a; int b; }; - struct my_pair *buffer; - MPI_Send(buffer, 1, MPI_DOUBLE_INT /*, ... */); // no warning because the - // layout of my_pair is - // compatible with that of - // internal_mpi_double_int - - struct my_int_pair { int a; int b; } - struct my_int_pair *buffer2; - MPI_Send(buffer2, 1, MPI_DOUBLE_INT /*, ... */); // warning because the - // layout of my_int_pair - // does not match that of - // internal_mpi_double_int - - * ``must_be_null`` specifies that the function argument specified by either - ``arg_idx`` (for the ``argument_with_type_tag`` attribute) or ``ptr_idx`` (for - the ``pointer_with_type_tag`` attribute) should be a null pointer constant. - The second argument to the ``type_tag_for_datatype`` attribute is ignored. For - example: - - .. code-block:: c++ - - /* In mpi.h */ - typedef int MPI_Datatype; - extern struct mpi_datatype mpi_datatype_null - __attribute__(( type_tag_for_datatype(mpi, void, must_be_null) )); - - #define MPI_DATATYPE_NULL ((MPI_Datatype) &mpi_datatype_null) - int MPI_Send(void *buf, int count, MPI_Datatype datatype, ...) - __attribute__(( pointer_with_type_tag(mpi,1,3) )); - - /* In user code */ - struct my_pair { double a; int b; }; - struct my_pair *buffer; - MPI_Send(buffer, 1, MPI_DATATYPE_NULL /*, ... */); // warning: MPI_DATATYPE_NULL - // was specified but buffer - // is not a null pointer - - -AMD GPU Attributes -================== - - -amdgpu_flat_work_group_size ---------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -The flat work-group size is the number of work-items in the work-group size -specified when the kernel is dispatched. It is the product of the sizes of the -x, y, and z dimension of the work-group. - -Clang supports the -``__attribute__((amdgpu_flat_work_group_size(<min>, <max>)))`` attribute for the -AMDGPU target. This attribute may be attached to a kernel function definition -and is an optimization hint. - -``<min>`` parameter specifies the minimum flat work-group size, and ``<max>`` -parameter specifies the maximum flat work-group size (must be greater than -``<min>``) to which all dispatches of the kernel will conform. Passing ``0, 0`` -as ``<min>, <max>`` implies the default behavior (``128, 256``). - -If specified, the AMDGPU target backend might be able to produce better machine -code for barriers and perform scratch promotion by estimating available group -segment size. - -An error will be given if: - - Specified values violate subtarget specifications; - - Specified values are not compatible with values provided through other - attributes. - - -amdgpu_num_sgpr ---------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Clang supports the ``__attribute__((amdgpu_num_sgpr(<num_sgpr>)))`` and -``__attribute__((amdgpu_num_vgpr(<num_vgpr>)))`` attributes for the AMDGPU -target. These attributes may be attached to a kernel function definition and are -an optimization hint. - -If these attributes are specified, then the AMDGPU target backend will attempt -to limit the number of SGPRs and/or VGPRs used to the specified value(s). The -number of used SGPRs and/or VGPRs may further be rounded up to satisfy the -allocation requirements or constraints of the subtarget. Passing ``0`` as -``num_sgpr`` and/or ``num_vgpr`` implies the default behavior (no limits). - -These attributes can be used to test the AMDGPU target backend. It is -recommended that the ``amdgpu_waves_per_eu`` attribute be used to control -resources such as SGPRs and VGPRs since it is aware of the limits for different -subtargets. - -An error will be given if: - - Specified values violate subtarget specifications; - - Specified values are not compatible with values provided through other - attributes; - - The AMDGPU target backend is unable to create machine code that can meet the - request. - - -amdgpu_num_vgpr ---------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Clang supports the ``__attribute__((amdgpu_num_sgpr(<num_sgpr>)))`` and -``__attribute__((amdgpu_num_vgpr(<num_vgpr>)))`` attributes for the AMDGPU -target. These attributes may be attached to a kernel function definition and are -an optimization hint. - -If these attributes are specified, then the AMDGPU target backend will attempt -to limit the number of SGPRs and/or VGPRs used to the specified value(s). The -number of used SGPRs and/or VGPRs may further be rounded up to satisfy the -allocation requirements or constraints of the subtarget. Passing ``0`` as -``num_sgpr`` and/or ``num_vgpr`` implies the default behavior (no limits). - -These attributes can be used to test the AMDGPU target backend. It is -recommended that the ``amdgpu_waves_per_eu`` attribute be used to control -resources such as SGPRs and VGPRs since it is aware of the limits for different -subtargets. - -An error will be given if: - - Specified values violate subtarget specifications; - - Specified values are not compatible with values provided through other - attributes; - - The AMDGPU target backend is unable to create machine code that can meet the - request. - - -amdgpu_waves_per_eu -------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -A compute unit (CU) is responsible for executing the wavefronts of a work-group. -It is composed of one or more execution units (EU), which are responsible for -executing the wavefronts. An EU can have enough resources to maintain the state -of more than one executing wavefront. This allows an EU to hide latency by -switching between wavefronts in a similar way to symmetric multithreading on a -CPU. In order to allow the state for multiple wavefronts to fit on an EU, the -resources used by a single wavefront have to be limited. For example, the number -of SGPRs and VGPRs. Limiting such resources can allow greater latency hiding, -but can result in having to spill some register state to memory. - -Clang supports the ``__attribute__((amdgpu_waves_per_eu(<min>[, <max>])))`` -attribute for the AMDGPU target. This attribute may be attached to a kernel -function definition and is an optimization hint. - -``<min>`` parameter specifies the requested minimum number of waves per EU, and -*optional* ``<max>`` parameter specifies the requested maximum number of waves -per EU (must be greater than ``<min>`` if specified). If ``<max>`` is omitted, -then there is no restriction on the maximum number of waves per EU other than -the one dictated by the hardware for which the kernel is compiled. Passing -``0, 0`` as ``<min>, <max>`` implies the default behavior (no limits). - -If specified, this attribute allows an advanced developer to tune the number of -wavefronts that are capable of fitting within the resources of an EU. The AMDGPU -target backend can use this information to limit resources, such as number of -SGPRs, number of VGPRs, size of available group and private memory segments, in -such a way that guarantees that at least ``<min>`` wavefronts and at most -``<max>`` wavefronts are able to fit within the resources of an EU. Requesting -more wavefronts can hide memory latency but limits available registers which -can result in spilling. Requesting fewer wavefronts can help reduce cache -thrashing, but can reduce memory latency hiding. - -This attribute controls the machine code generated by the AMDGPU target backend -to ensure it is capable of meeting the requested values. However, when the -kernel is executed, there may be other reasons that prevent meeting the request, -for example, there may be wavefronts from other kernels executing on the EU. - -An error will be given if: - - Specified values violate subtarget specifications; - - Specified values are not compatible with values provided through other - attributes; - - The AMDGPU target backend is unable to create machine code that can meet the - request. - - -Calling Conventions -=================== -Clang supports several different calling conventions, depending on the target -platform and architecture. The calling convention used for a function determines -how parameters are passed, how results are returned to the caller, and other -low-level details of calling a function. - -fastcall (gnu::fastcall, __fastcall, _fastcall) ------------------------------------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","X", "" - -On 32-bit x86 targets, this attribute changes the calling convention of a -function to use ECX and EDX as register parameters and clear parameters off of -the stack on return. This convention does not support variadic calls or -unprototyped functions in C, and has no effect on x86_64 targets. This calling -convention is supported primarily for compatibility with existing code. Users -seeking register parameters should use the ``regparm`` attribute, which does -not require callee-cleanup. See the documentation for `__fastcall`_ on MSDN. - -.. _`__fastcall`: http://msdn.microsoft.com/en-us/library/6xa169sk.aspx - - -ms_abi (gnu::ms_abi) --------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -On non-Windows x86_64 targets, this attribute changes the calling convention of -a function to match the default convention used on Windows x86_64. This -attribute has no effect on Windows targets or non-x86_64 targets. - - -pcs (gnu::pcs) --------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -On ARM targets, this attribute can be used to select calling conventions -similar to ``stdcall`` on x86. Valid parameter values are "aapcs" and -"aapcs-vfp". - - -preserve_all ------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -On X86-64 and AArch64 targets, this attribute changes the calling convention of -a function. The ``preserve_all`` calling convention attempts to make the code -in the caller even less intrusive than the ``preserve_most`` calling convention. -This calling convention also behaves identical to the ``C`` calling convention -on how arguments and return values are passed, but it uses a different set of -caller/callee-saved registers. This removes the burden of saving and -recovering a large register set before and after the call in the caller. If -the arguments are passed in callee-saved registers, then they will be -preserved by the callee across the call. This doesn't apply for values -returned in callee-saved registers. - -- On X86-64 the callee preserves all general purpose registers, except for - R11. R11 can be used as a scratch register. Furthermore it also preserves - all floating-point registers (XMMs/YMMs). - -The idea behind this convention is to support calls to runtime functions -that don't need to call out to any other functions. - -This calling convention, like the ``preserve_most`` calling convention, will be -used by a future version of the Objective-C runtime and should be considered -experimental at this time. - - -preserve_most -------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -On X86-64 and AArch64 targets, this attribute changes the calling convention of -a function. The ``preserve_most`` calling convention attempts to make the code -in the caller as unintrusive as possible. This convention behaves identically -to the ``C`` calling convention on how arguments and return values are passed, -but it uses a different set of caller/callee-saved registers. This alleviates -the burden of saving and recovering a large register set before and after the -call in the caller. If the arguments are passed in callee-saved registers, -then they will be preserved by the callee across the call. This doesn't -apply for values returned in callee-saved registers. - -- On X86-64 the callee preserves all general purpose registers, except for - R11. R11 can be used as a scratch register. Floating-point registers - (XMMs/YMMs) are not preserved and need to be saved by the caller. - -The idea behind this convention is to support calls to runtime functions -that have a hot path and a cold path. The hot path is usually a small piece -of code that doesn't use many registers. The cold path might need to call out to -another function and therefore only needs to preserve the caller-saved -registers, which haven't already been saved by the caller. The -`preserve_most` calling convention is very similar to the ``cold`` calling -convention in terms of caller/callee-saved registers, but they are used for -different types of function calls. ``coldcc`` is for function calls that are -rarely executed, whereas `preserve_most` function calls are intended to be -on the hot path and definitely executed a lot. Furthermore ``preserve_most`` -doesn't prevent the inliner from inlining the function call. - -This calling convention will be used by a future version of the Objective-C -runtime and should therefore still be considered experimental at this time. -Although this convention was created to optimize certain runtime calls to -the Objective-C runtime, it is not limited to this runtime and might be used -by other runtimes in the future too. The current implementation only -supports X86-64 and AArch64, but the intention is to support more architectures -in the future. - - -regcall (gnu::regcall, __regcall) ---------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","X", "" - -On x86 targets, this attribute changes the calling convention to -`__regcall`_ convention. This convention aims to pass as many arguments -as possible in registers. It also tries to utilize registers for the -return value whenever it is possible. - -.. _`__regcall`: https://software.intel.com/en-us/node/693069 - - -regparm (gnu::regparm) ----------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -On 32-bit x86 targets, the regparm attribute causes the compiler to pass -the first three integer parameters in EAX, EDX, and ECX instead of on the -stack. This attribute has no effect on variadic functions, and all parameters -are passed via the stack as normal. - - -stdcall (gnu::stdcall, __stdcall, _stdcall) -------------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","X", "" - -On 32-bit x86 targets, this attribute changes the calling convention of a -function to clear parameters off of the stack on return. This convention does -not support variadic calls or unprototyped functions in C, and has no effect on -x86_64 targets. This calling convention is used widely by the Windows API and -COM applications. See the documentation for `__stdcall`_ on MSDN. - -.. _`__stdcall`: http://msdn.microsoft.com/en-us/library/zxk0tw93.aspx - - -thiscall (gnu::thiscall, __thiscall, _thiscall) ------------------------------------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","X", "" - -On 32-bit x86 targets, this attribute changes the calling convention of a -function to use ECX for the first parameter (typically the implicit ``this`` -parameter of C++ methods) and clear parameters off of the stack on return. This -convention does not support variadic calls or unprototyped functions in C, and -has no effect on x86_64 targets. See the documentation for `__thiscall`_ on -MSDN. - -.. _`__thiscall`: http://msdn.microsoft.com/en-us/library/ek8tkfbw.aspx - - -vectorcall (__vectorcall, _vectorcall) --------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","X", "" - -On 32-bit x86 *and* x86_64 targets, this attribute changes the calling -convention of a function to pass vector parameters in SSE registers. - -On 32-bit x86 targets, this calling convention is similar to ``__fastcall``. -The first two integer parameters are passed in ECX and EDX. Subsequent integer -parameters are passed in memory, and callee clears the stack. On x86_64 -targets, the callee does *not* clear the stack, and integer parameters are -passed in RCX, RDX, R8, and R9 as is done for the default Windows x64 calling -convention. - -On both 32-bit x86 and x86_64 targets, vector and floating point arguments are -passed in XMM0-XMM5. Homogeneous vector aggregates of up to four elements are -passed in sequential SSE registers if enough are available. If AVX is enabled, -256 bit vectors are passed in YMM0-YMM5. Any vector or aggregate type that -cannot be passed in registers for any reason is passed by reference, which -allows the caller to align the parameter memory. - -See the documentation for `__vectorcall`_ on MSDN for more details. - -.. _`__vectorcall`: http://msdn.microsoft.com/en-us/library/dn375768.aspx - - -Consumed Annotation Checking -============================ -Clang supports additional attributes for checking basic resource management -properties, specifically for unique objects that have a single owning reference. -The following attributes are currently supported, although **the implementation -for these annotations is currently in development and are subject to change.** - -callable_when -------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Use ``__attribute__((callable_when(...)))`` to indicate what states a method -may be called in. Valid states are unconsumed, consumed, or unknown. Each -argument to this attribute must be a quoted string. E.g.: - -``__attribute__((callable_when("unconsumed", "unknown")))`` - - -consumable ----------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Each ``class`` that uses any of the typestate annotations must first be marked -using the ``consumable`` attribute. Failure to do so will result in a warning. - -This attribute accepts a single parameter that must be one of the following: -``unknown``, ``consumed``, or ``unconsumed``. - - -param_typestate ---------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -This attribute specifies expectations about function parameters. Calls to an -function with annotated parameters will issue a warning if the corresponding -argument isn't in the expected state. The attribute is also used to set the -initial state of the parameter when analyzing the function's body. - - -return_typestate ----------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -The ``return_typestate`` attribute can be applied to functions or parameters. -When applied to a function the attribute specifies the state of the returned -value. The function's body is checked to ensure that it always returns a value -in the specified state. On the caller side, values returned by the annotated -function are initialized to the given state. - -When applied to a function parameter it modifies the state of an argument after -a call to the function returns. The function's body is checked to ensure that -the parameter is in the expected state before returning. - - -set_typestate -------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Annotate methods that transition an object into a new state with -``__attribute__((set_typestate(new_state)))``. The new state must be -unconsumed, consumed, or unknown. - - -test_typestate --------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","","","", "" - -Use ``__attribute__((test_typestate(tested_state)))`` to indicate that a method -returns true if the object is in the specified state.. - - -OpenCL Address Spaces -===================== -The address space qualifier may be used to specify the region of memory that is -used to allocate the object. OpenCL supports the following address spaces: -__generic(generic), __global(global), __local(local), __private(private), -__constant(constant). - - .. code-block:: c - - __constant int c = ...; - - __generic int* foo(global int* g) { - __local int* l; - private int p; - ... - return l; - } - -More details can be found in the OpenCL C language Spec v2.0, Section 6.5. - -constant (__constant) ---------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The constant address space attribute signals that an object is located in -a constant (non-modifiable) memory region. It is available to all work items. -Any type can be annotated with the constant address space attribute. Objects -with the constant address space qualifier can be declared in any scope and must -have an initializer. - - -generic (__generic) -------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The generic address space attribute is only available with OpenCL v2.0 and later. -It can be used with pointer types. Variables in global and local scope and -function parameters in non-kernel functions can have the generic address space -type attribute. It is intended to be a placeholder for any other address space -except for '__constant' in OpenCL code which can be used with multiple address -spaces. - - -global (__global) ------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The global address space attribute specifies that an object is allocated in -global memory, which is accessible by all work items. The content stored in this -memory area persists between kernel executions. Pointer types to the global -address space are allowed as function parameters or local variables. Starting -with OpenCL v2.0, the global address space can be used with global (program -scope) variables and static local variable as well. - - -local (__local) ---------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The local address space specifies that an object is allocated in the local (work -group) memory area, which is accessible to all work items in the same work -group. The content stored in this memory region is not accessible after -the kernel execution ends. In a kernel function scope, any variable can be in -the local address space. In other scopes, only pointer types to the local address -space are allowed. Local address space variables cannot have an initializer. - - -private (__private) -------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The private address space specifies that an object is allocated in the private -(work item) memory. Other work items cannot access the same memory area and its -content is destroyed after work item execution ends. Local variables can be -declared in the private address space. Function arguments are always in the -private address space. Kernel function arguments of a pointer or an array type -cannot point to the private address space. - - -Nullability Attributes -====================== -Whether a particular pointer may be "null" is an important concern when working with pointers in the C family of languages. The various nullability attributes indicate whether a particular pointer can be null or not, which makes APIs more expressive and can help static analysis tools identify bugs involving null pointers. Clang supports several kinds of nullability attributes: the ``nonnull`` and ``returns_nonnull`` attributes indicate which function or method parameters and result types can never be null, while nullability type qualifiers indicate which pointer types can be null (``_Nullable``) or cannot be null (``_Nonnull``). - -The nullability (type) qualifiers express whether a value of a given pointer type can be null (the ``_Nullable`` qualifier), doesn't have a defined meaning for null (the ``_Nonnull`` qualifier), or for which the purpose of null is unclear (the ``_Null_unspecified`` qualifier). Because nullability qualifiers are expressed within the type system, they are more general than the ``nonnull`` and ``returns_nonnull`` attributes, allowing one to express (for example) a nullable pointer to an array of nonnull pointers. Nullability qualifiers are written to the right of the pointer to which they apply. For example: - - .. code-block:: c - - // No meaningful result when 'ptr' is null (here, it happens to be undefined behavior). - int fetch(int * _Nonnull ptr) { return *ptr; } - - // 'ptr' may be null. - int fetch_or_zero(int * _Nullable ptr) { - return ptr ? *ptr : 0; - } - - // A nullable pointer to non-null pointers to const characters. - const char *join_strings(const char * _Nonnull * _Nullable strings, unsigned n); - -In Objective-C, there is an alternate spelling for the nullability qualifiers that can be used in Objective-C methods and properties using context-sensitive, non-underscored keywords. For example: - - .. code-block:: objective-c - - @interface NSView : NSResponder - - (nullable NSView *)ancestorSharedWithView:(nonnull NSView *)aView; - @property (assign, nullable) NSView *superview; - @property (readonly, nonnull) NSArray *subviews; - @end - -nonnull (gnu::nonnull) ----------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``nonnull`` attribute indicates that some function parameters must not be null, and can be used in several different ways. It's original usage (`from GCC <https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes>`_) is as a function (or Objective-C method) attribute that specifies which parameters of the function are nonnull in a comma-separated list. For example: - - .. code-block:: c - - extern void * my_memcpy (void *dest, const void *src, size_t len) - __attribute__((nonnull (1, 2))); - -Here, the ``nonnull`` attribute indicates that parameters 1 and 2 -cannot have a null value. Omitting the parenthesized list of parameter indices means that all parameters of pointer type cannot be null: - - .. code-block:: c - - extern void * my_memcpy (void *dest, const void *src, size_t len) - __attribute__((nonnull)); - -Clang also allows the ``nonnull`` attribute to be placed directly on a function (or Objective-C method) parameter, eliminating the need to specify the parameter index ahead of type. For example: - - .. code-block:: c - - extern void * my_memcpy (void *dest __attribute__((nonnull)), - const void *src __attribute__((nonnull)), size_t len); - -Note that the ``nonnull`` attribute indicates that passing null to a non-null parameter is undefined behavior, which the optimizer may take advantage of to, e.g., remove null checks. The ``_Nonnull`` type qualifier indicates that a pointer cannot be null in a more general manner (because it is part of the type system) and does not imply undefined behavior, making it more widely applicable. - - -returns_nonnull (gnu::returns_nonnull) --------------------------------------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "X","X","","", "" - -The ``returns_nonnull`` attribute indicates that a particular function (or Objective-C method) always returns a non-null pointer. For example, a particular system ``malloc`` might be defined to terminate a process when memory is not available rather than returning a null pointer: - - .. code-block:: c - - extern void * malloc (size_t size) __attribute__((returns_nonnull)); - -The ``returns_nonnull`` attribute implies that returning a null pointer is undefined behavior, which the optimizer may take advantage of. The ``_Nonnull`` type qualifier indicates that a pointer cannot be null in a more general manner (because it is part of the type system) and does not imply undefined behavior, making it more widely applicable - - -_Nonnull --------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The ``_Nonnull`` nullability qualifier indicates that null is not a meaningful value for a value of the ``_Nonnull`` pointer type. For example, given a declaration such as: - - .. code-block:: c - - int fetch(int * _Nonnull ptr); - -a caller of ``fetch`` should not provide a null value, and the compiler will produce a warning if it sees a literal null value passed to ``fetch``. Note that, unlike the declaration attribute ``nonnull``, the presence of ``_Nonnull`` does not imply that passing null is undefined behavior: ``fetch`` is free to consider null undefined behavior or (perhaps for backward-compatibility reasons) defensively handle null. - - -_Null_unspecified ------------------ -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The ``_Null_unspecified`` nullability qualifier indicates that neither the ``_Nonnull`` nor ``_Nullable`` qualifiers make sense for a particular pointer type. It is used primarily to indicate that the role of null with specific pointers in a nullability-annotated header is unclear, e.g., due to overly-complex implementations or historical factors with a long-lived API. - - -_Nullable ---------- -.. csv-table:: Supported Syntaxes - :header: "GNU", "C++11", "__declspec", "Keyword", "Pragma" - - "","","","X", "" - -The ``_Nullable`` nullability qualifier indicates that a value of the ``_Nullable`` pointer type can be null. For example, given: - - .. code-block:: c - - int fetch_or_zero(int * _Nullable ptr); - -a caller of ``fetch_or_zero`` can provide null. - - +===================
\ No newline at end of file diff --git a/docs/ClangCommandLineReference.rst b/docs/ClangCommandLineReference.rst new file mode 100644 index 000000000000..add168829e1b --- /dev/null +++ b/docs/ClangCommandLineReference.rst @@ -0,0 +1,2591 @@ +.. + ------------------------------------------------------------------- + NOTE: This file is automatically generated by running clang-tblgen + -gen-opt-docs. Do not edit this file by hand!! + ------------------------------------------------------------------- + +===================================== +Clang command line argument reference +===================================== +.. contents:: + :local: + +Introduction +============ + +This page lists the command line arguments currently supported by the +GCC-compatible ``clang`` and ``clang++`` drivers. + + +.. program:: clang +.. option:: -B<dir>, --prefix <arg>, --prefix=<arg> + +Add <dir> to search path for binaries and object files used implicitly + +.. option:: -F<arg> + +Add directory to framework include search path + +.. option:: -ObjC + +Treat source input files as Objective-C inputs + +.. program:: clang1 +.. option:: -ObjC++ +.. program:: clang + +Treat source input files as Objective-C++ inputs + +.. option:: -Qunused-arguments + +Don't emit warning for unused driver arguments + +.. option:: -Wa,<arg>,<arg2>... + +Pass the comma separated arguments in <arg> to the assembler + +.. option:: -Wlarge-by-value-copy=<arg> + +.. option:: -Xarch\_<arg1> <arg2> + +.. option:: -Xcuda-fatbinary <arg> + +Pass <arg> to fatbinary invocation + +.. option:: -Xcuda-ptxas <arg> + +Pass <arg> to the ptxas assembler + +.. option:: -Z<arg> + +.. option:: -a<arg>, --profile-blocks + +.. option:: -all\_load + +.. option:: -allowable\_client <arg> + +.. option:: --analyze + +Run the static analyzer + +.. option:: --analyze-auto + +.. option:: --analyzer-no-default-checks + +.. option:: --analyzer-output<arg> + +Static analyzer report output format (html\|plist\|plist-multi-file\|plist-html\|text). + +.. option:: -ansi, --ansi + +.. option:: -arch <arg> + +.. program:: clang1 +.. option:: -arch\_errors\_fatal +.. program:: clang + +.. program:: clang2 +.. option:: -arch\_only <arg> +.. program:: clang + +.. option:: -arcmt-migrate-emit-errors + +Emit ARC errors even if the migrator can fix them + +.. option:: -arcmt-migrate-report-output <arg> + +Output path for the plist report + +.. option:: -bind\_at\_load + +.. option:: -bundle + +.. program:: clang1 +.. option:: -bundle\_loader <arg> +.. program:: clang + +.. option:: -client\_name<arg> + +.. option:: -compatibility\_version<arg> + +.. option:: --constant-cfstrings + +.. option:: -coverage, --coverage + +.. option:: --cuda-compile-host-device + +Compile CUDA code for both host and device (default). Has no effect on non-CUDA compilations. + +.. option:: --cuda-device-only + +Compile CUDA code for device only + +.. option:: --cuda-gpu-arch=<arg>, --no-cuda-gpu-arch=<arg> + +CUDA GPU architecture (e.g. sm\_35). May be specified more than once. + +.. option:: --cuda-host-only + +Compile CUDA code for host only. Has no effect on non-CUDA compilations. + +.. option:: --cuda-noopt-device-debug, --no-cuda-noopt-device-debug + +Enable device-side debug info generation. Disables ptxas optimizations. + +.. option:: -current\_version<arg> + +.. option:: -dead\_strip + +.. option:: -dependency-dot <arg> + +Filename to write DOT-formatted header dependencies to + +.. option:: -dependency-file <arg> + +Filename (or -) to write dependency output to + +.. option:: -dumpmachine + +.. option:: -dumpversion + +.. option:: --dyld-prefix=<arg>, --dyld-prefix <arg> + +.. option:: -dylib\_file <arg> + +.. option:: -dylinker + +.. program:: clang1 +.. option:: -dylinker\_install\_name<arg> +.. program:: clang + +.. option:: -dynamic + +.. option:: -dynamiclib + +.. option:: -emit-ast + +Emit Clang AST files for source inputs + +.. option:: -exported\_symbols\_list <arg> + +.. option:: -faligned-new=<arg> + +.. option:: -fcuda-approx-transcendentals, -fno-cuda-approx-transcendentals + +Use approximate transcendental functions + +.. option:: -fcuda-flush-denormals-to-zero, -fno-cuda-flush-denormals-to-zero + +Flush denormal floating point values to zero in CUDA device mode. + +.. option:: -fheinous-gnu-extensions + +.. option:: -flat\_namespace + +.. option:: -fopenmp-targets=<arg1>,<arg2>... + +Specify comma-separated list of triples OpenMP offloading targets to be supported + +.. option:: -force\_cpusubtype\_ALL + +.. program:: clang1 +.. option:: -force\_flat\_namespace +.. program:: clang + +.. program:: clang2 +.. option:: -force\_load <arg> +.. program:: clang + +.. option:: -framework <arg> + +.. option:: -frtlib-add-rpath, -fno-rtlib-add-rpath + +Add -rpath with architecture-specific resource directory to the linker flags + +.. option:: --gcc-toolchain=<arg>, -gcc-toolchain <arg> + +Use the gcc toolchain at the given directory + +.. option:: -gcodeview + +Generate CodeView debug information + +.. option:: -headerpad\_max\_install\_names<arg> + +.. option:: -help, --help + +Display available options + +.. option:: --help-hidden + +.. option:: -image\_base <arg> + +.. option:: -index-header-map + +Make the next included directory (-I or -F) an indexer header map + +.. option:: -init <arg> + +.. option:: -install\_name <arg> + +.. option:: -keep\_private\_externs + +.. option:: -lazy\_framework <arg> + +.. program:: clang1 +.. option:: -lazy\_library <arg> +.. program:: clang + +.. option:: -mbig-endian, -EB + +.. option:: --migrate + +Run the migrator + +.. option:: -mios-simulator-version-min=<arg>, -miphonesimulator-version-min=<arg> + +.. option:: -mlinker-version=<arg> + +.. option:: -mlittle-endian, -EL + +.. option:: -mllvm <arg> + +Additional arguments to forward to LLVM's option processing + +.. option:: -module-dependency-dir <arg> + +Directory to dump module dependencies to + +.. option:: -mtvos-simulator-version-min=<arg>, -mappletvsimulator-version-min=<arg> + +.. option:: -multi\_module + +.. option:: -multiply\_defined <arg> + +.. program:: clang1 +.. option:: -multiply\_defined\_unused <arg> +.. program:: clang + +.. option:: -mwatchos-simulator-version-min=<arg>, -mwatchsimulator-version-min=<arg> + +.. option:: --no-cuda-version-check + +Don't error out if the detected version of the CUDA install is too low for the requested CUDA gpu architecture. + +.. option:: -no-integrated-cpp, --no-integrated-cpp + +.. option:: -no\_dead\_strip\_inits\_and\_terms + +.. option:: -nobuiltininc + +Disable builtin #include directories + +.. option:: -nocudainc + +.. option:: -nocudalib + +.. option:: -nodefaultlibs + +.. option:: -nofixprebinding + +.. option:: -nolibc + +.. option:: -nomultidefs + +.. option:: -nopie + +.. option:: -noprebind + +.. option:: -noseglinkedit + +.. option:: -nostartfiles + +.. option:: -nostdinc, --no-standard-includes + +.. program:: clang1 +.. option:: -nostdinc++ +.. program:: clang + +Disable standard #include directories for the C++ standard library + +.. option:: -nostdlib, --no-standard-libraries + +.. option:: -nostdlibinc + +.. option:: -o<file>, --output <arg>, --output=<arg> + +Write output to <file> + +.. option:: -objcmt-atomic-property + +Make migration to 'atomic' properties + +.. option:: -objcmt-migrate-all + +Enable migration to modern ObjC + +.. option:: -objcmt-migrate-annotation + +Enable migration to property and method annotations + +.. option:: -objcmt-migrate-designated-init + +Enable migration to infer NS\_DESIGNATED\_INITIALIZER for initializer methods + +.. option:: -objcmt-migrate-instancetype + +Enable migration to infer instancetype for method result type + +.. option:: -objcmt-migrate-literals + +Enable migration to modern ObjC literals + +.. option:: -objcmt-migrate-ns-macros + +Enable migration to NS\_ENUM/NS\_OPTIONS macros + +.. option:: -objcmt-migrate-property + +Enable migration to modern ObjC property + +.. option:: -objcmt-migrate-property-dot-syntax + +Enable migration of setter/getter messages to property-dot syntax + +.. option:: -objcmt-migrate-protocol-conformance + +Enable migration to add protocol conformance on classes + +.. option:: -objcmt-migrate-readonly-property + +Enable migration to modern ObjC readonly property + +.. option:: -objcmt-migrate-readwrite-property + +Enable migration to modern ObjC readwrite property + +.. option:: -objcmt-migrate-subscripting + +Enable migration to modern ObjC subscripting + +.. option:: -objcmt-ns-nonatomic-iosonly + +Enable migration to use NS\_NONATOMIC\_IOSONLY macro for setting property's 'atomic' attribute + +.. option:: -objcmt-returns-innerpointer-property + +Enable migration to annotate property with NS\_RETURNS\_INNER\_POINTER + +.. option:: -objcmt-whitelist-dir-path=<arg>, -objcmt-white-list-dir-path=<arg> + +Only modify files with a filename contained in the provided directory path + +.. option:: -object + +.. option:: -p, --profile + +.. option:: -pagezero\_size<arg> + +.. option:: -pg + +Enable mcount instrumentation + +.. option:: -pie + +.. option:: -pipe, --pipe + +Use pipes between commands, when possible + +.. option:: -prebind + +.. program:: clang1 +.. option:: -prebind\_all\_twolevel\_modules +.. program:: clang + +.. option:: -preload + +.. option:: --print-diagnostic-categories + +.. option:: -print-file-name=<file>, --print-file-name=<file>, --print-file-name <arg> + +Print the full library path of <file> + +.. option:: -print-ivar-layout + +Enable Objective-C Ivar layout bitmap print trace + +.. option:: -print-libgcc-file-name, --print-libgcc-file-name + +Print the library path for the currently used compiler runtime library ("libgcc.a" or "libclang\_rt.builtins.\*.a") + +.. option:: -print-multi-directory, --print-multi-directory + +.. option:: -print-multi-lib, --print-multi-lib + +.. option:: -print-prog-name=<name>, --print-prog-name=<name>, --print-prog-name <arg> + +Print the full program path of <name> + +.. option:: -print-resource-dir, --print-resource-dir + +Print the resource directory pathname + +.. option:: -print-search-dirs, --print-search-dirs + +Print the paths used for finding libraries and programs + +.. option:: -private\_bundle + +.. option:: -pthread, -no-pthread + +Support POSIX threads in generated code + +.. option:: -pthreads + +.. option:: -rdynamic + +.. option:: -read\_only\_relocs <arg> + +.. option:: -relocatable-pch, --relocatable-pch + +Whether to build a relocatable precompiled header + +.. option:: -remap + +.. option:: -rewrite-legacy-objc + +Rewrite Legacy Objective-C source to C++ + +.. option:: -rtlib=<arg>, --rtlib=<arg>, --rtlib <arg> + +Compiler runtime library to use + +.. option:: -save-stats=<arg>, --save-stats=<arg>, -save-stats (equivalent to -save-stats=cwd), --save-stats (equivalent to -save-stats=cwd) + +Save llvm statistics. + +.. option:: -save-temps=<arg>, --save-temps=<arg>, -save-temps (equivalent to -save-temps=cwd), --save-temps (equivalent to -save-temps=cwd) + +Save intermediate compilation results. + +.. option:: -sectalign <arg1> <arg2> <arg3> + +.. option:: -sectcreate <arg1> <arg2> <arg3> + +.. option:: -sectobjectsymbols <arg1> <arg2> + +.. option:: -sectorder <arg1> <arg2> <arg3> + +.. option:: -seg1addr<arg> + +.. option:: -seg\_addr\_table <arg> + +.. program:: clang1 +.. option:: -seg\_addr\_table\_filename <arg> +.. program:: clang + +.. option:: -segaddr <arg1> <arg2> + +.. option:: -segcreate <arg1> <arg2> <arg3> + +.. option:: -seglinkedit + +.. option:: -segprot <arg1> <arg2> <arg3> + +.. option:: -segs\_read\_<arg> + +.. program:: clang1 +.. option:: -segs\_read\_only\_addr <arg> +.. program:: clang + +.. program:: clang2 +.. option:: -segs\_read\_write\_addr <arg> +.. program:: clang + +.. option:: -serialize-diagnostics <arg>, --serialize-diagnostics <arg> + +Serialize compiler diagnostics to a file + +.. option:: -shared, --shared + +.. option:: -shared-libasan + +.. option:: -shared-libgcc + +.. option:: -single\_module + +.. option:: -specs=<arg>, --specs=<arg> + +.. option:: -static, --static + +.. option:: -static-libgcc + +.. option:: -static-libstdc++ + +.. option:: -std-default=<arg> + +.. option:: -stdlib=<arg>, --stdlib=<arg>, --stdlib <arg> + +C++ standard library to use + +.. option:: -sub\_library<arg> + +.. program:: clang1 +.. option:: -sub\_umbrella<arg> +.. program:: clang + +.. option:: --sysroot=<arg>, --sysroot <arg> + +.. option:: --target-help + +.. option:: --target=<arg>, -target <arg> + +Generate code for the given target + +.. option:: -time + +Time individual commands + +.. option:: -traditional, --traditional + +.. option:: -traditional-cpp, --traditional-cpp + +Enable some traditional CPP emulation + +.. option:: -twolevel\_namespace + +.. program:: clang1 +.. option:: -twolevel\_namespace\_hints +.. program:: clang + +.. option:: -umbrella <arg> + +.. option:: -unexported\_symbols\_list <arg> + +.. option:: -v, --verbose + +Show commands to run and use verbose output + +.. option:: --verify-debug-info + +Verify the binary representation of debug output + +.. option:: --version + +.. option:: -w, --no-warnings + +Suppress all warnings + +.. option:: -weak-l<arg> + +.. option:: -weak\_framework <arg> + +.. program:: clang1 +.. option:: -weak\_library <arg> +.. program:: clang + +.. program:: clang2 +.. option:: -weak\_reference\_mismatches <arg> +.. program:: clang + +.. option:: -whatsloaded + +.. option:: -whyload + +.. option:: -working-directory<arg>, -working-directory=<arg> + +Resolve file paths relative to the specified directory + +.. option:: -x<language>, --language <arg>, --language=<arg> + +Treat subsequent input files as having type <language> + +.. option:: -y<arg> + +Actions +======= +The action to perform on the input. + +.. option:: -E, --preprocess + +Only run the preprocessor + +.. option:: -S, --assemble + +Only run preprocess and compilation steps + +.. option:: -c, --compile + +Only run preprocess, compile, and assemble steps + +.. option:: -emit-llvm + +Use the LLVM representation for assembler and object files + +.. option:: -fsyntax-only + +.. option:: -module-file-info + +Provide information about a particular module file + +.. option:: --precompile + +Only precompile the input + +.. option:: -rewrite-objc + +Rewrite Objective-C source to C++ + +.. option:: -verify-pch + +Load and verify that a pre-compiled header file is not stale + +Compilation flags +================= + +Flags controlling the behavior of Clang during compilation. These flags have +no effect during actions that do not perform compilation. + +.. option:: -Xassembler <arg> + +Pass <arg> to the assembler + +.. option:: -Xclang <arg> + +Pass <arg> to the clang compiler + +.. option:: -fcomment-block-commands=<arg>,<arg2>... + +Treat each comma separated argument in <arg> as a documentation comment block command + +.. option:: -fdeclspec, -fno-declspec + +Allow \_\_declspec as a keyword + +.. option:: -fdepfile-entry=<arg> + +.. option:: -fdiagnostics-fixit-info, -fno-diagnostics-fixit-info + +.. option:: -fdiagnostics-format=<arg> + +.. option:: -fdiagnostics-parseable-fixits + +Print fix-its in machine parseable form + +.. option:: -fdiagnostics-print-source-range-info + +Print source range spans in numeric form + +.. option:: -fdiagnostics-show-category=<arg> + +.. option:: -fexperimental-new-pass-manager, -fno-experimental-new-pass-manager + +Enables an experimental new pass manager in LLVM. + +.. option:: -finline-functions, -fno-inline-functions + +Inline suitable functions + +.. option:: -finline-hint-functions + +Inline functions which are (explicitly or implicitly) marked inline + +.. option:: -fno-crash-diagnostics + +Disable auto-generation of preprocessed source files and a script for reproduction during a clang crash + +.. option:: -fno-sanitize-blacklist + +Don't use blacklist file for sanitizers + +.. option:: -fparse-all-comments + +.. option:: -fsanitize-address-field-padding=<arg> + +Level of field padding for AddressSanitizer + +.. option:: -fsanitize-address-use-after-scope, -fno-sanitize-address-use-after-scope + +Enable use-after-scope detection in AddressSanitizer + +.. option:: -fsanitize-blacklist=<arg> + +Path to blacklist file for sanitizers + +.. option:: -fsanitize-cfi-cross-dso, -fno-sanitize-cfi-cross-dso + +Enable control flow integrity (CFI) checks for cross-DSO calls. + +.. option:: -fsanitize-coverage=<arg1>,<arg2>..., -fno-sanitize-coverage=<arg1>,<arg2>... + +Specify the type of coverage instrumentation for Sanitizers + +.. option:: -fsanitize-link-c++-runtime + +.. option:: -fsanitize-memory-track-origins, -fno-sanitize-memory-track-origins + +Enable origins tracking in MemorySanitizer + +.. program:: clang1 +.. option:: -fsanitize-memory-track-origins=<arg> +.. program:: clang + +Enable origins tracking in MemorySanitizer + +.. option:: -fsanitize-memory-use-after-dtor + +Enable use-after-destroy detection in MemorySanitizer + +.. option:: -fsanitize-recover, -fno-sanitize-recover + +.. program:: clang1 +.. option:: -fsanitize-recover=<arg1>,<arg2>..., -fno-sanitize-recover=<arg1>,<arg2>... +.. program:: clang + +Enable recovery for specified sanitizers + +.. option:: -fsanitize-stats, -fno-sanitize-stats + +Enable sanitizer statistics gathering. + +.. option:: -fsanitize-thread-atomics, -fno-sanitize-thread-atomics + +Enable atomic operations instrumentation in ThreadSanitizer (default) + +.. option:: -fsanitize-thread-func-entry-exit, -fno-sanitize-thread-func-entry-exit + +Enable function entry/exit instrumentation in ThreadSanitizer (default) + +.. option:: -fsanitize-thread-memory-access, -fno-sanitize-thread-memory-access + +Enable memory access instrumentation in ThreadSanitizer (default) + +.. option:: -fsanitize-trap=<arg1>,<arg2>..., -fno-sanitize-trap=<arg1>,<arg2>... + +Enable trapping for specified sanitizers + +.. option:: -fsanitize-undefined-strip-path-components=<number> + +Strip (or keep only, if negative) a given number of path components when emitting check metadata. + +.. option:: -fsanitize-undefined-trap-on-error, -fno-sanitize-undefined-trap-on-error + +.. option:: -fsanitize=<check>,<arg2>..., -fno-sanitize=<arg1>,<arg2>... + +Turn on runtime checks for various forms of undefined or suspicious behavior. See user manual for available checks + +.. option:: --param <arg>, --param=<arg> + +.. option:: -std=<arg>, --std=<arg>, --std <arg> + +Language standard to compile for + +Preprocessor flags +~~~~~~~~~~~~~~~~~~ + +Flags controlling the behavior of the Clang preprocessor. + +.. option:: -C, --comments + +Include comments in preprocessed output + +.. option:: -CC, --comments-in-macros + +Include comments from within macros in preprocessed output + +.. option:: -D<macro>=<value>, --define-macro <arg>, --define-macro=<arg> + +Define <macro> to <value> (or 1 if <value> omitted) + +.. option:: -H, --trace-includes + +Show header includes and nesting depth + +.. option:: -P, --no-line-commands + +Disable linemarker output in -E mode + +.. option:: -U<macro>, --undefine-macro <arg>, --undefine-macro=<arg> + +Undefine macro <macro> + +.. option:: -Wp,<arg>,<arg2>... + +Pass the comma separated arguments in <arg> to the preprocessor + +.. option:: -Xpreprocessor <arg> + +Pass <arg> to the preprocessor + +Include path management +----------------------- + +Flags controlling how ``#include``\s are resolved to files. + +.. option:: -I<dir>, --include-directory <arg>, --include-directory=<arg> + +Add directory to include search path + +.. option:: -I-, --include-barrier + +Restrict all prior -I flags to double-quoted inclusion and remove current directory from include path + +.. option:: --cuda-path=<arg> + +CUDA installation path + +.. option:: -cxx-isystem<directory> + +Add directory to the C++ SYSTEM include search path + +.. option:: -fbuild-session-file=<file> + +Use the last modification time of <file> as the build session timestamp + +.. option:: -fbuild-session-timestamp=<time since Epoch in seconds> + +Time when the current build session started + +.. option:: -fmodules-cache-path=<directory> + +Specify the module cache path + +.. option:: -fmodules-disable-diagnostic-validation + +Disable validation of the diagnostic options when loading the module + +.. option:: -fmodules-prune-after=<seconds> + +Specify the interval (in seconds) after which a module file will be considered unused + +.. option:: -fmodules-prune-interval=<seconds> + +Specify the interval (in seconds) between attempts to prune the module cache + +.. option:: -fmodules-user-build-path <directory> + +Specify the module user build path + +.. option:: -fmodules-validate-once-per-build-session + +Don't verify input files for the modules if the module has been successfully validated or loaded during this build session + +.. option:: -fmodules-validate-system-headers + +Validate the system headers that a module depends on when loading the module + +.. option:: -fprebuilt-module-path=<directory> + +Specify the prebuilt module path + +.. option:: -i<arg> + +.. option:: -idirafter<arg>, --include-directory-after <arg>, --include-directory-after=<arg> + +Add directory to AFTER include search path + +.. option:: -iframework<arg> + +Add directory to SYSTEM framework search path + +.. option:: -iframeworkwithsysroot<directory> + +Add directory to SYSTEM framework search path, absolute paths are relative to -isysroot + +.. option:: -imacros<file>, --imacros<file>, --imacros=<arg> + +Include macros from file before parsing + +.. option:: -include<file>, --include<file>, --include=<arg> + +Include file before parsing + +.. option:: -include-pch <file> + +Include precompiled header file + +.. option:: -iprefix<dir>, --include-prefix <arg>, --include-prefix=<arg> + +Set the -iwithprefix/-iwithprefixbefore prefix + +.. option:: -iquote<directory> + +Add directory to QUOTE include search path + +.. option:: -isysroot<dir> + +Set the system root directory (usually /) + +.. option:: -isystem<directory> + +Add directory to SYSTEM include search path + +.. option:: -isystem-after<directory> + +Add directory to end of the SYSTEM include search path + +.. option:: -ivfsoverlay<arg> + +Overlay the virtual filesystem described by file over the real file system + +.. option:: -iwithprefix<dir>, --include-with-prefix <arg>, --include-with-prefix-after <arg>, --include-with-prefix-after=<arg>, --include-with-prefix=<arg> + +Set directory to SYSTEM include search path with prefix + +.. option:: -iwithprefixbefore<dir>, --include-with-prefix-before <arg>, --include-with-prefix-before=<arg> + +Set directory to include search path with prefix + +.. option:: -iwithsysroot<directory> + +Add directory to SYSTEM include search path, absolute paths are relative to -isysroot + +.. option:: --ptxas-path=<arg> + +Path to ptxas (used for compiling CUDA code) + +.. option:: --system-header-prefix=<prefix>, --no-system-header-prefix=<prefix>, --system-header-prefix <arg> + +Treat all #include paths starting with <prefix> as including a system header. + +Dependency file generation +-------------------------- + +Flags controlling generation of a dependency file for ``make``-like build +systems. + +.. option:: -M, --dependencies + +Like -MD, but also implies -E and writes to stdout by default + +.. option:: -MD, --write-dependencies + +Write a depfile containing user and system headers + +.. option:: -MF<file> + +Write depfile output from -MMD, -MD, -MM, or -M to <file> + +.. option:: -MG, --print-missing-file-dependencies + +Add missing headers to depfile + +.. option:: -MJ<arg> + +Write a compilation database entry per input + +.. option:: -MM, --user-dependencies + +Like -MMD, but also implies -E and writes to stdout by default + +.. option:: -MMD, --write-user-dependencies + +Write a depfile containing user headers + +.. option:: -MP + +Create phony target for each dependency (other than main file) + +.. option:: -MQ<arg> + +Specify name of main file output to quote in depfile + +.. option:: -MT<arg> + +Specify name of main file output in depfile + +.. option:: -MV + +Use NMake/Jom format for the depfile + +Dumping preprocessor state +-------------------------- + +Flags allowing the state of the preprocessor to be dumped in various ways. + +.. option:: -d + +.. program:: clang1 +.. option:: -d<arg> +.. program:: clang + +.. option:: -dA + +.. option:: -dD + +Print macro definitions in -E mode in addition to normal output + +.. option:: -dI + +Print include directives in -E mode in addition to normal output + +.. option:: -dM + +Print macro definitions in -E mode instead of normal output + +Diagnostic flags +~~~~~~~~~~~~~~~~ + +Flags controlling which warnings, errors, and remarks Clang will generate. +See the :doc:`full list of warning and remark flags <DiagnosticsReference>`. + +.. option:: -R<remark> + +Enable the specified remark + +.. option:: -Rpass-analysis=<arg> + +Report transformation analysis from optimization passes whose name matches the given POSIX regular expression + +.. option:: -Rpass-missed=<arg> + +Report missed transformations by optimization passes whose name matches the given POSIX regular expression + +.. option:: -Rpass=<arg> + +Report transformations performed by optimization passes whose name matches the given POSIX regular expression + +.. option:: -W<warning>, --extra-warnings, --warn-<arg>, --warn-=<arg> + +Enable the specified warning + +.. option:: -Wdeprecated, -Wno-deprecated + +Enable warnings for deprecated constructs and define \_\_DEPRECATED + +.. option:: -Wnonportable-cfstrings<arg>, -Wno-nonportable-cfstrings<arg> + +Target-independent compilation options +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.. option:: -Wframe-larger-than=<arg> + +.. option:: -fPIC, -fno-PIC + +.. option:: -fPIE, -fno-PIE + +.. option:: -faccess-control, -fno-access-control + +.. program:: clang1 +.. option:: -faligned-allocation, -faligned-new, -fno-aligned-allocation +.. program:: clang + +Enable C++17 aligned allocation functions + +.. option:: -fallow-unsupported + +.. option:: -faltivec, -fno-altivec + +.. option:: -fansi-escape-codes + +Use ANSI escape codes for diagnostics + +.. option:: -fapple-kext, -findirect-virtual-calls, -fterminated-vtables + +Use Apple's kernel extensions ABI + +.. option:: -fapple-pragma-pack, -fno-apple-pragma-pack + +Enable Apple gcc-compatible #pragma pack handling + +.. option:: -fapplication-extension, -fno-application-extension + +Restrict code to those available for App Extensions + +.. option:: -fasm, -fno-asm + +.. option:: -fasm-blocks, -fno-asm-blocks + +.. option:: -fassociative-math, -fno-associative-math + +.. option:: -fassume-sane-operator-new, -fno-assume-sane-operator-new + +.. option:: -fast + +.. option:: -fastcp + +.. option:: -fastf + +.. option:: -fasynchronous-unwind-tables, -fno-asynchronous-unwind-tables + +.. option:: -fautolink, -fno-autolink + +.. option:: -fblocks, -fno-blocks + +Enable the 'blocks' language feature + +.. option:: -fbootclasspath=<arg>, --bootclasspath <arg>, --bootclasspath=<arg> + +.. option:: -fborland-extensions, -fno-borland-extensions + +Accept non-standard constructs supported by the Borland compiler + +.. option:: -fbracket-depth=<arg> + +.. option:: -fbuiltin, -fno-builtin + +.. option:: -fbuiltin-module-map + +Load the clang builtins module map file. + +.. option:: -fcaret-diagnostics, -fno-caret-diagnostics + +.. option:: -fclasspath=<arg>, --CLASSPATH <arg>, --CLASSPATH=<arg>, --classpath <arg>, --classpath=<arg> + +.. option:: -fcolor-diagnostics, -fno-color-diagnostics + +Use colors in diagnostics + +.. option:: -fcommon, -fno-common + +.. option:: -fcompile-resource=<arg>, --resource <arg>, --resource=<arg> + +.. option:: -fconstant-cfstrings, -fno-constant-cfstrings + +.. option:: -fconstant-string-class=<arg> + +.. option:: -fconstexpr-backtrace-limit=<arg> + +.. option:: -fconstexpr-depth=<arg> + +.. option:: -fconstexpr-steps=<arg> + +.. option:: -fcoroutines-ts, -fno-coroutines-ts + +Enable support for the C++ Coroutines TS + +.. option:: -fcoverage-mapping, -fno-coverage-mapping + +Generate coverage mapping to enable code coverage analysis + +.. option:: -fcreate-profile + +.. option:: -fcxx-exceptions, -fno-cxx-exceptions + +Enable C++ exceptions + +.. option:: -fcxx-modules, -fno-cxx-modules + +.. option:: -fdata-sections, -fno-data-sections + +Place each data in its own section (ELF Only) + +.. option:: -fdebug-info-for-profiling, -fno-debug-info-for-profiling + +Emit extra debug info to make sample profile more accurate. + +.. option:: -fdebug-macro, -fno-debug-macro + +Emit macro debug information + +.. option:: -fdebug-pass-arguments + +.. option:: -fdebug-pass-structure + +.. option:: -fdebug-prefix-map=<arg> + +remap file source paths in debug info + +.. option:: -fdebug-types-section, -fno-debug-types-section + +Place debug types in their own section (ELF Only) + +.. option:: -fdelayed-template-parsing, -fno-delayed-template-parsing + +Parse templated function definitions at the end of the translation unit + +.. option:: -fdenormal-fp-math=<arg> + +.. option:: -fdiagnostics-absolute-paths + +Print absolute paths in diagnostics + +.. option:: -fdiagnostics-color, -fno-diagnostics-color + +.. program:: clang1 +.. option:: -fdiagnostics-color=<arg> +.. program:: clang + +.. option:: -fdiagnostics-show-hotness, -fno-diagnostics-show-hotness + +Enable profile hotness information in diagnostic line + +.. option:: -fdiagnostics-show-note-include-stack, -fno-diagnostics-show-note-include-stack + +Display include stacks for diagnostic notes + +.. option:: -fdiagnostics-show-option, -fno-diagnostics-show-option + +Print option name with mappable diagnostics + +.. option:: -fdiagnostics-show-template-tree + +Print a template comparison tree for differing templates + +.. option:: -fdollars-in-identifiers, -fno-dollars-in-identifiers + +Allow '$' in identifiers + +.. option:: -fdwarf-directory-asm, -fno-dwarf-directory-asm + +.. option:: -felide-constructors, -fno-elide-constructors + +.. option:: -feliminate-unused-debug-symbols, -fno-eliminate-unused-debug-symbols + +.. option:: -fembed-bitcode=<option>, -fembed-bitcode (equivalent to -fembed-bitcode=all), -fembed-bitcode-marker (equivalent to -fembed-bitcode=marker) + +Embed LLVM bitcode (option: off, all, bitcode, marker) + +.. option:: -femit-all-decls + +Emit all declarations, even if unused + +.. option:: -femulated-tls, -fno-emulated-tls + +Use emutls functions to access thread\_local variables + +.. option:: -fencoding=<arg>, --encoding <arg>, --encoding=<arg> + +.. option:: -ferror-limit=<arg> + +.. option:: -fexceptions, -fno-exceptions + +Enable support for exception handling + +.. option:: -fexec-charset=<arg> + +.. option:: -fextdirs=<arg>, --extdirs <arg>, --extdirs=<arg> + +.. option:: -ffast-math, -fno-fast-math + +Allow aggressive, lossy floating-point optimizations + +.. option:: -ffinite-math-only, -fno-finite-math-only + +.. option:: -ffor-scope, -fno-for-scope + +.. option:: -ffp-contract=<arg> + +Form fused FP ops (e.g. FMAs): fast (everywhere) \| on (according to FP\_CONTRACT pragma, default) \| off (never fuse) + +.. option:: -ffreestanding + +Assert that the compilation takes place in a freestanding environment + +.. option:: -ffunction-sections, -fno-function-sections + +Place each function in its own section (ELF Only) + +.. option:: -fgnu-inline-asm, -fno-gnu-inline-asm + +.. option:: -fgnu-keywords, -fno-gnu-keywords + +Allow GNU-extension keywords regardless of language standard + +.. option:: -fgnu-runtime + +Generate output compatible with the standard GNU Objective-C runtime + +.. option:: -fgnu89-inline, -fno-gnu89-inline + +Use the gnu89 inline semantics + +.. option:: -fhonor-infinities, -fhonor-infinites, -fno-honor-infinities + +.. option:: -fhonor-nans, -fno-honor-nans + +.. option:: -fhosted + +.. option:: -fimplicit-module-maps, -fmodule-maps, -fno-implicit-module-maps + +Implicitly search the file system for module map files. + +.. option:: -fimplicit-modules, -fno-implicit-modules + +.. option:: -finput-charset=<arg> + +.. option:: -finstrument-functions + +Generate calls to instrument function entry and exit + +.. option:: -fintegrated-as, -fno-integrated-as, -integrated-as + +Enable the integrated assembler + +.. option:: -fjump-tables, -fno-jump-tables + +.. option:: -flax-vector-conversions, -fno-lax-vector-conversions + +.. option:: -flimited-precision=<arg> + +.. option:: -flto, -fno-lto + +Enable LTO in 'full' mode + +.. option:: -flto-jobs=<arg> + +Controls the backend parallelism of -flto=thin (default of 0 means the number of threads will be derived from the number of CPUs detected) + +.. program:: clang1 +.. option:: -flto=<arg> +.. program:: clang + +Set LTO mode to either 'full' or 'thin' + +.. option:: -fmacro-backtrace-limit=<arg> + +.. option:: -fmath-errno, -fno-math-errno + +Require math functions to indicate errors by setting errno + +.. option:: -fmax-type-align=<arg> + +Specify the maximum alignment to enforce on pointers lacking an explicit alignment + +.. option:: -fmerge-all-constants, -fno-merge-all-constants + +.. option:: -fmessage-length=<arg> + +.. option:: -fmodule-file-deps, -fno-module-file-deps + +.. option:: -fmodule-file=<file> + +Load this precompiled module file + +.. option:: -fmodule-map-file=<file> + +Load this module map file + +.. option:: -fmodule-name=<name>, -fmodule-implementation-of <arg>, -fmodule-name <arg> + +Specify the name of the module to build + +.. option:: -fmodules, -fno-modules + +Enable the 'modules' language feature + +.. option:: -fmodules-decluse, -fno-modules-decluse + +Require declaration of modules used within a module + +.. option:: -fmodules-ignore-macro=<arg> + +Ignore the definition of the given macro when building and loading modules + +.. option:: -fmodules-search-all, -fno-modules-search-all + +Search even non-imported modules to resolve references + +.. option:: -fmodules-strict-decluse + +Like -fmodules-decluse but requires all headers to be in modules + +.. option:: -fmodules-ts + +Enable support for the C++ Modules TS + +.. option:: -fms-compatibility, -fno-ms-compatibility + +Enable full Microsoft Visual C++ compatibility + +.. option:: -fms-compatibility-version=<arg> + +Dot-separated value representing the Microsoft compiler version number to report in \_MSC\_VER (0 = don't define it (default)) + +.. option:: -fms-extensions, -fno-ms-extensions + +Accept some non-standard constructs supported by the Microsoft compiler + +.. option:: -fms-memptr-rep=<arg> + +.. option:: -fms-volatile<arg> + +.. option:: -fmsc-version=<arg> + +Microsoft compiler version number to report in \_MSC\_VER (0 = don't define it (default)) + +.. option:: -fmudflap + +.. option:: -fmudflapth + +.. option:: -fnested-functions + +.. option:: -fnew-alignment=<align>, -fnew-alignment <arg> + +Specifies the largest alignment guaranteed by '::operator new(size\_t)' + +.. option:: -fnext-runtime + +.. option:: -fno-builtin-<arg> + +Disable implicit builtin knowledge of a specific function + +.. option:: -fno-elide-type + +Do not elide types when printing diagnostics + +.. option:: -fno-max-type-align + +.. option:: -fno-operator-names + +Do not treat C++ operator name keywords as synonyms for operators + +.. option:: -fno-strict-modules-decluse + +.. option:: -fno-working-directory + +.. option:: -fnoopenmp-use-tls + +.. option:: -fobjc-abi-version=<arg> + +.. option:: -fobjc-arc, -fno-objc-arc + +Synthesize retain and release calls for Objective-C pointers + +.. option:: -fobjc-arc-exceptions, -fno-objc-arc-exceptions + +Use EH-safe code when synthesizing retains and releases in -fobjc-arc + +.. option:: -fobjc-exceptions, -fno-objc-exceptions + +Enable Objective-C exceptions + +.. option:: -fobjc-infer-related-result-type, -fno-objc-infer-related-result-type + +.. option:: -fobjc-legacy-dispatch, -fno-objc-legacy-dispatch + +.. option:: -fobjc-link-runtime + +.. option:: -fobjc-nonfragile-abi, -fno-objc-nonfragile-abi + +.. option:: -fobjc-nonfragile-abi-version=<arg> + +.. option:: -fobjc-runtime=<arg> + +Specify the target Objective-C runtime kind and version + +.. option:: -fobjc-sender-dependent-dispatch + +.. option:: -fobjc-weak, -fno-objc-weak + +Enable ARC-style weak references in Objective-C + +.. option:: -fomit-frame-pointer, -fno-omit-frame-pointer + +.. option:: -fopenmp, -fno-openmp + +.. option:: -fopenmp-dump-offload-linker-script + +.. option:: -fopenmp-use-tls + +.. option:: -fopenmp-version=<arg> + +.. program:: clang1 +.. option:: -fopenmp=<arg> +.. program:: clang + +.. option:: -foperator-arrow-depth=<arg> + +.. option:: -foptimization-record-file=<arg> + +Specify the file name of any generated YAML optimization record + +.. option:: -foptimize-sibling-calls, -fno-optimize-sibling-calls + +.. option:: -foutput-class-dir=<arg>, --output-class-directory <arg>, --output-class-directory=<arg> + +.. option:: -fpack-struct, -fno-pack-struct + +.. program:: clang1 +.. option:: -fpack-struct=<arg> +.. program:: clang + +Specify the default maximum struct packing alignment + +.. option:: -fpascal-strings, -fno-pascal-strings, -mpascal-strings + +Recognize and construct Pascal-style string literals + +.. option:: -fpcc-struct-return + +Override the default ABI to return all structs on the stack + +.. option:: -fpch-preprocess + +.. option:: -fpic, -fno-pic + +.. option:: -fpie, -fno-pie + +.. option:: -fplugin=<dsopath> + +Load the named plugin (dynamic shared object) + +.. option:: -fpreserve-as-comments, -fno-preserve-as-comments + +.. option:: -fprofile-arcs, -fno-profile-arcs + +.. option:: -fprofile-dir=<arg> + +.. option:: -fprofile-generate, -fno-profile-generate + +Generate instrumented code to collect execution counts into default.profraw (overridden by LLVM\_PROFILE\_FILE env var) + +.. program:: clang1 +.. option:: -fprofile-generate=<directory> +.. program:: clang + +Generate instrumented code to collect execution counts into <directory>/default.profraw (overridden by LLVM\_PROFILE\_FILE env var) + +.. option:: -fprofile-instr-generate, -fno-profile-instr-generate + +Generate instrumented code to collect execution counts into default.profraw file (overridden by '=' form of option or LLVM\_PROFILE\_FILE env var) + +.. program:: clang1 +.. option:: -fprofile-instr-generate=<file> +.. program:: clang + +Generate instrumented code to collect execution counts into <file> (overridden by LLVM\_PROFILE\_FILE env var) + +.. option:: -fprofile-instr-use, -fno-profile-instr-use, -fprofile-use + +.. program:: clang1 +.. option:: -fprofile-instr-use=<arg> +.. program:: clang + +Use instrumentation data for profile-guided optimization + +.. option:: -fprofile-sample-use, -fauto-profile, -fno-profile-sample-use + +.. program:: clang1 +.. option:: -fprofile-sample-use=<arg>, -fauto-profile=<arg> +.. program:: clang + +Enable sample-based profile guided optimizations + +.. program:: clang1 +.. option:: -fprofile-use=<pathname> +.. program:: clang + +Use instrumentation data for profile-guided optimization. If pathname is a directory, it reads from <pathname>/default.profdata. Otherwise, it reads from file <pathname>. + +.. option:: -freciprocal-math, -fno-reciprocal-math + +Allow division operations to be reassociated + +.. option:: -freg-struct-return + +Override the default ABI to return small structs in registers + +.. option:: -frelaxed-template-template-args, -fno-relaxed-template-template-args + +Enable C++17 relaxed template template argument matching + +.. option:: -freroll-loops, -fno-reroll-loops + +Turn on loop reroller + +.. option:: -fretain-comments-from-system-headers + +.. option:: -frewrite-includes, -fno-rewrite-includes + +.. option:: -frewrite-map-file <arg> + +.. program:: clang1 +.. option:: -frewrite-map-file=<arg> +.. program:: clang + +.. option:: -fropi, -fno-ropi + +.. option:: -frtti, -fno-rtti + +.. option:: -frwpi, -fno-rwpi + +.. option:: -fsave-optimization-record, -fno-save-optimization-record + +Generate a YAML optimization record file + +.. option:: -fshort-enums, -fno-short-enums + +Allocate to an enum type only as many bytes as it needs for the declared range of possible values + +.. option:: -fshort-wchar, -fno-short-wchar + +Force wchar\_t to be a short unsigned int + +.. option:: -fshow-column, -fno-show-column + +.. option:: -fshow-overloads=<arg> + +Which overload candidates to show when overload resolution fails: best\|all; defaults to all + +.. option:: -fshow-source-location, -fno-show-source-location + +.. option:: -fsignaling-math, -fno-signaling-math + +.. option:: -fsigned-bitfields + +.. option:: -fsigned-char, -fno-signed-char, --signed-char + +.. option:: -fsigned-zeros, -fno-signed-zeros + +.. option:: -fsized-deallocation, -fno-sized-deallocation + +Enable C++14 sized global deallocation functions + +.. option:: -fsjlj-exceptions + +Use SjLj style exceptions + +.. option:: -fslp-vectorize, -fno-slp-vectorize, -ftree-slp-vectorize + +Enable the superword-level parallelism vectorization passes + +.. option:: -fslp-vectorize-aggressive, -fno-slp-vectorize-aggressive + +Enable the BB vectorization passes + +.. option:: -fspell-checking, -fno-spell-checking + +.. option:: -fspell-checking-limit=<arg> + +.. option:: -fsplit-dwarf-inlining, -fno-split-dwarf-inlining + +Place debug types in their own section (ELF Only) + +.. option:: -fsplit-stack + +.. option:: -fstack-protector, -fno-stack-protector + +Enable stack protectors for functions potentially vulnerable to stack smashing + +.. option:: -fstack-protector-all + +Force the usage of stack protectors for all functions + +.. option:: -fstack-protector-strong + +Use a strong heuristic to apply stack protectors to functions + +.. option:: -fstandalone-debug, -fno-limit-debug-info, -fno-standalone-debug + +Emit full debug info for all types used by the program + +.. option:: -fstrict-aliasing, -fno-strict-aliasing + +.. option:: -fstrict-enums, -fno-strict-enums + +Enable optimizations based on the strict definition of an enum's value range + +.. option:: -fstrict-overflow, -fno-strict-overflow + +.. option:: -fstrict-return, -fno-strict-return + +Always treat control flow paths that fall off the end of a non-void function as unreachable + +.. option:: -fstrict-vtable-pointers, -fno-strict-vtable-pointers + +Enable optimizations based on the strict rules for overwriting polymorphic C++ objects + +.. option:: -fstruct-path-tbaa, -fno-struct-path-tbaa + +.. option:: -ftabstop=<arg> + +.. option:: -ftemplate-backtrace-limit=<arg> + +.. option:: -ftemplate-depth-<arg> + +.. option:: -ftemplate-depth=<arg> + +.. option:: -ftest-coverage + +.. option:: -fthinlto-index=<arg> + +Perform ThinLTO importing using provided function summary index + +.. option:: -fthreadsafe-statics, -fno-threadsafe-statics + +.. option:: -ftime-report + +.. option:: -ftls-model=<arg> + +.. option:: -ftrap-function=<arg> + +Issue call to specified function rather than a trap instruction + +.. option:: -ftrapping-math, -fno-trapping-math + +.. option:: -ftrapv + +Trap on integer overflow + +.. option:: -ftrapv-handler <arg> + +.. program:: clang1 +.. option:: -ftrapv-handler=<function name> +.. program:: clang + +Specify the function to be called on overflow + +.. option:: -ftrigraphs, -fno-trigraphs, -trigraphs, --trigraphs + +Process trigraph sequences + +.. option:: -funique-section-names, -fno-unique-section-names + +Use unique names for text and data sections (ELF Only) + +.. option:: -funit-at-a-time, -fno-unit-at-a-time + +.. option:: -funroll-loops, -fno-unroll-loops + +Turn on loop unroller + +.. option:: -funsafe-math-optimizations, -fno-unsafe-math-optimizations + +.. option:: -funsigned-bitfields + +.. option:: -funsigned-char, -fno-unsigned-char, --unsigned-char + +.. option:: -funwind-tables, -fno-unwind-tables + +.. option:: -fuse-cxa-atexit, -fno-use-cxa-atexit + +.. option:: -fuse-init-array, -fno-use-init-array + +Use .init\_array instead of .ctors + +.. option:: -fuse-ld=<arg> + +.. option:: -fuse-line-directives, -fno-use-line-directives + +.. option:: -fveclib=<arg> + +Use the given vector functions library + +.. option:: -fvectorize, -fno-vectorize, -ftree-vectorize + +Enable the loop vectorization passes + +.. option:: -fverbose-asm, -fno-verbose-asm + +.. option:: -fvisibility-inlines-hidden + +Give inline C++ member functions default visibility by default + +.. option:: -fvisibility-ms-compat + +Give global types 'default' visibility and global functions and variables 'hidden' visibility by default + +.. option:: -fvisibility=<arg> + +Set the default symbol visibility for all global declarations + +.. option:: -fwhole-program-vtables, -fno-whole-program-vtables + +Enables whole-program vtable optimization. Requires -flto + +.. option:: -fwrapv, -fno-wrapv + +Treat signed integer overflow as two's complement + +.. option:: -fwritable-strings + +Store string literals as writable data + +.. option:: -fxray-always-instrument=<arg> + +Filename defining the whitelist for imbuing the 'always instrument' XRay attribute. + +.. option:: -fxray-instruction-threshold<arg> + +.. program:: clang1 +.. option:: -fxray-instruction-threshold=<arg> +.. program:: clang + +Sets the minimum function size to instrument with XRay + +.. option:: -fxray-instrument, -fno-xray-instrument + +Generate XRay instrumentation sleds on function entry and exit + +.. option:: -fxray-never-instrument=<arg> + +Filename defining the whitelist for imbuing the 'never instrument' XRay attribute. + +.. option:: -fzero-initialized-in-bss, -fno-zero-initialized-in-bss + +.. option:: -fzvector, -fno-zvector, -mzvector + +Enable System z vector language extension + +.. option:: -pedantic, --pedantic, -no-pedantic, --no-pedantic + +.. option:: -pedantic-errors, --pedantic-errors + +OpenCL flags +------------ +.. option:: -cl-denorms-are-zero + +OpenCL only. Allow denormals to be flushed to zero. + +.. option:: -cl-fast-relaxed-math + +OpenCL only. Sets -cl-finite-math-only and -cl-unsafe-math-optimizations, and defines \_\_FAST\_RELAXED\_MATH\_\_. + +.. option:: -cl-finite-math-only + +OpenCL only. Allow floating-point optimizations that assume arguments and results are not NaNs or +-Inf. + +.. option:: -cl-fp32-correctly-rounded-divide-sqrt + +OpenCL only. Specify that single precision floating-point divide and sqrt used in the program source are correctly rounded. + +.. option:: -cl-kernel-arg-info + +OpenCL only. Generate kernel argument metadata. + +.. option:: -cl-mad-enable + +OpenCL only. Allow use of less precise MAD computations in the generated binary. + +.. option:: -cl-no-signed-zeros + +OpenCL only. Allow use of less precise no signed zeros computations in the generated binary. + +.. option:: -cl-opt-disable + +OpenCL only. This option disables all optimizations. By default optimizations are enabled. + +.. option:: -cl-single-precision-constant + +OpenCL only. Treat double precision floating-point constant as single precision constant. + +.. option:: -cl-std=<arg> + +OpenCL language standard to compile for. + +.. option:: -cl-strict-aliasing + +OpenCL only. This option is added for compatibility with OpenCL 1.0. + +.. option:: -cl-unsafe-math-optimizations + +OpenCL only. Allow unsafe floating-point optimizations. Also implies -cl-no-signed-zeros and -cl-mad-enable. + +Target-dependent compilation options +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.. option:: -G<size>, -G=<arg>, -msmall-data-threshold=<arg> + +Put objects of at most <size> bytes into small data section (MIPS / Hexagon) + +.. option:: -m16 + +.. option:: -m32 + +.. option:: -m64 + +.. option:: -mabi=<arg> + +.. option:: -mabicalls, -mno-abicalls + +Enable SVR4-style position-independent code (Mips only) + +.. option:: -malign-double + +Align doubles to two words in structs (x86 only) + +.. option:: -march=<arg> + +.. option:: -masm=<arg> + +.. option:: -mbackchain, -mno-backchain + +Link stack frames through backchain on System Z + +.. option:: -mcheck-zero-division, -mno-check-zero-division + +.. option:: -mcmodel=<arg> + +.. option:: -mcompact-branches=<arg> + +.. option:: -mconsole<arg> + +.. option:: -mcpu=<arg>, -mv4 (equivalent to -mcpu=hexagonv4), -mv5 (equivalent to -mcpu=hexagonv5), -mv55 (equivalent to -mcpu=hexagonv55), -mv60 (equivalent to -mcpu=hexagonv60), -mv62 (equivalent to -mcpu=hexagonv62) + +.. option:: -mdll<arg> + +.. option:: -mdouble-float + +.. option:: -mdsp, -mno-dsp + +.. option:: -mdspr2, -mno-dspr2 + +.. option:: -mdynamic-no-pic<arg> + +.. option:: -meabi <arg> + +Set EABI type, e.g. 4, 5 or gnu (default depends on triple) + +.. option:: -mfentry + +Insert calls to fentry at function entry (x86 only) + +.. option:: -mfloat-abi=<arg> + +.. option:: -mfp32 + +Use 32-bit floating point registers (MIPS only) + +.. option:: -mfp64 + +Use 64-bit floating point registers (MIPS only) + +.. option:: -mfpmath=<arg> + +.. option:: -mfpu=<arg> + +.. option:: -mglobal-merge, -mno-global-merge + +Enable merging of globals + +.. option:: -mhard-float + +.. option:: -mhwdiv=<arg>, --mhwdiv <arg>, --mhwdiv=<arg> + +.. option:: -miamcu, -mno-iamcu + +Use Intel MCU ABI + +.. option:: -mimplicit-float, -mno-implicit-float + +.. option:: -mimplicit-it=<arg> + +.. option:: -mincremental-linker-compatible, -mno-incremental-linker-compatible + +(integrated-as) Emit an object file which can be used with an incremental linker + +.. option:: -miphoneos-version-min=<arg>, -mios-version-min=<arg> + +.. option:: -mips16 + +.. option:: -mkernel + +.. option:: -mldc1-sdc1, -mno-ldc1-sdc1 + +.. option:: -mlong-calls, -mno-long-calls + +Generate branches with extended addressability, usually via indirect jumps. + +.. option:: -mmacosx-version-min=<arg> + +Set Mac OS X deployment target + +.. option:: -mmicromips, -mno-micromips + +.. option:: -mms-bitfields, -mno-ms-bitfields + +Set the default structure layout to be compatible with the Microsoft compiler standard + +.. option:: -mmsa, -mno-msa + +Enable MSA ASE (MIPS only) + +.. option:: -mnan=<arg> + +.. option:: -mno-mips16 + +.. option:: -momit-leaf-frame-pointer, -mno-omit-leaf-frame-pointer + +Omit frame pointer setup for leaf functions + +.. option:: -moslib=<arg> + +.. option:: -mpie-copy-relocations, -mno-pie-copy-relocations + +Use copy relocations support for PIE builds + +.. option:: -mqdsp6-compat + +Enable hexagon-qdsp6 backward compatibility + +.. option:: -mrecip + +.. program:: clang1 +.. option:: -mrecip=<arg1>,<arg2>... +.. program:: clang + +.. option:: -mred-zone, -mno-red-zone + +.. option:: -mregparm=<arg> + +.. option:: -mrelax-all, -mno-relax-all + +(integrated-as) Relax all machine instructions + +.. option:: -mrtd, -mno-rtd + +Make StdCall calling convention the default + +.. option:: -msingle-float + +.. option:: -msoft-float, -mno-soft-float + +Use software floating point + +.. option:: -mstack-alignment=<arg> + +Set the stack alignment + +.. option:: -mstack-probe-size=<arg> + +Set the stack probe size + +.. option:: -mstackrealign, -mno-stackrealign + +Force realign the stack at entry to every function + +.. option:: -mthread-model <arg> + +The thread model to use, e.g. posix, single (posix by default) + +.. option:: -mthreads<arg> + +.. option:: -mthumb, -mno-thumb + +.. option:: -mtune=<arg> + +.. option:: -mtvos-version-min=<arg>, -mappletvos-version-min=<arg> + +.. option:: -municode<arg> + +.. option:: -mvx, -mno-vx + +.. option:: -mwarn-nonportable-cfstrings, -mno-warn-nonportable-cfstrings + +.. option:: -mwatchos-version-min=<arg> + +.. option:: -mwindows<arg> + +.. option:: -mx32 + +.. option:: -mxgot, -mno-xgot + +AARCH64 +------- +.. option:: -ffixed-x18 + +Reserve the x18 register (AArch64 only) + +.. option:: -mfix-cortex-a53-835769, -mno-fix-cortex-a53-835769 + +Workaround Cortex-A53 erratum 835769 (AArch64 only) + +.. option:: -mgeneral-regs-only + +Generate code which only uses the general purpose registers (AArch64 only) + +AMDGPU +------ +ARM +--- +.. option:: -ffixed-r9 + +Reserve the r9 register (ARM only) + +.. option:: -mcrc + +Allow use of CRC instructions (ARM only) + +.. option:: -mexecute-only, -mno-execute-only, -mpure-code + +Disallow generation of data access to code sections (ARM only) + +.. option:: -mno-movt + +Disallow use of movt/movw pairs (ARM only) + +.. option:: -mno-neg-immediates + +Disallow converting instructions with negative immediates to their negation or inversion. + +.. option:: -mnocrc + +Disallow use of CRC instructions (ARM only) + +.. option:: -mrestrict-it, -mno-restrict-it + +Disallow generation of deprecated IT blocks for ARMv8. It is on by default for ARMv8 Thumb mode. + +.. option:: -munaligned-access, -mno-unaligned-access + +Allow memory accesses to be unaligned (AArch32/AArch64 only) + +Hexagon +------- +.. option:: -mhvx, -mno-hvx + +Enable Hexagon Vector eXtensions + +.. option:: -mhvx-double, -mno-hvx-double + +Enable Hexagon Double Vector eXtensions + +.. option:: -mieee-rnd-near + +PowerPC +------- +.. option:: -maltivec, -mno-altivec + +.. option:: -mcmpb, -mno-cmpb + +.. option:: -mcrbits, -mno-crbits + +.. option:: -mcrypto, -mno-crypto + +.. option:: -mdirect-move, -mno-direct-move + +.. option:: -mfloat128, -mno-float128 + +.. option:: -mfprnd, -mno-fprnd + +.. option:: -mhtm, -mno-htm + +.. option:: -minvariant-function-descriptors, -mno-invariant-function-descriptors + +.. option:: -misel, -mno-isel + +.. option:: -mlongcall, -mno-longcall + +.. option:: -mmfocrf, -mmfcrf, -mno-mfocrf + +.. option:: -mpopcntd, -mno-popcntd + +.. option:: -mpower8-vector, -mno-power8-vector + +.. option:: -mpower9-vector, -mno-power9-vector + +.. option:: -mqpx, -mno-qpx + +.. option:: -mvsx, -mno-vsx + +WebAssembly +----------- +.. option:: -msimd128, -mno-simd128 + +X86 +--- +.. option:: -m3dnow, -mno-3dnow + +.. option:: -m3dnowa, -mno-3dnowa + +.. option:: -madx, -mno-adx + +.. option:: -maes, -mno-aes + +.. option:: -mavx, -mno-avx + +.. option:: -mavx2, -mno-avx2 + +.. option:: -mavx512bw, -mno-avx512bw + +.. option:: -mavx512cd, -mno-avx512cd + +.. option:: -mavx512dq, -mno-avx512dq + +.. option:: -mavx512er, -mno-avx512er + +.. option:: -mavx512f, -mno-avx512f + +.. option:: -mavx512ifma, -mno-avx512ifma + +.. option:: -mavx512pf, -mno-avx512pf + +.. option:: -mavx512vbmi, -mno-avx512vbmi + +.. option:: -mavx512vl, -mno-avx512vl + +.. option:: -mbmi, -mno-bmi + +.. option:: -mbmi2, -mno-bmi2 + +.. option:: -mclflushopt, -mno-clflushopt + +.. option:: -mclwb, -mno-clwb + +.. option:: -mclzero, -mno-clzero + +.. option:: -mcx16, -mno-cx16 + +.. option:: -mf16c, -mno-f16c + +.. option:: -mfma, -mno-fma + +.. option:: -mfma4, -mno-fma4 + +.. option:: -mfsgsbase, -mno-fsgsbase + +.. option:: -mfxsr, -mno-fxsr + +.. option:: -mlzcnt, -mno-lzcnt + +.. option:: -mmmx, -mno-mmx + +.. option:: -mmovbe, -mno-movbe + +.. option:: -mmpx, -mno-mpx + +.. option:: -mmwaitx, -mno-mwaitx + +.. option:: -mpclmul, -mno-pclmul + +.. option:: -mpku, -mno-pku + +.. option:: -mpopcnt, -mno-popcnt + +.. option:: -mprefetchwt1, -mno-prefetchwt1 + +.. option:: -mprfchw, -mno-prfchw + +.. option:: -mrdrnd, -mno-rdrnd + +.. option:: -mrdseed, -mno-rdseed + +.. option:: -mrtm, -mno-rtm + +.. option:: -msgx, -mno-sgx + +.. option:: -msha, -mno-sha + +.. option:: -msse, -mno-sse + +.. option:: -msse2, -mno-sse2 + +.. option:: -msse3, -mno-sse3 + +.. option:: -msse4.1, -mno-sse4.1 + +.. program:: clang1 +.. option:: -msse4.2, -mno-sse4.2, -msse4 +.. program:: clang + +.. option:: -msse4a, -mno-sse4a + +.. option:: -mssse3, -mno-ssse3 + +.. option:: -mtbm, -mno-tbm + +.. option:: -mx87, -m80387, -mno-x87 + +.. option:: -mxop, -mno-xop + +.. option:: -mxsave, -mno-xsave + +.. option:: -mxsavec, -mno-xsavec + +.. option:: -mxsaveopt, -mno-xsaveopt + +.. option:: -mxsaves, -mno-xsaves + +Optimization level +~~~~~~~~~~~~~~~~~~ + +Flags controlling how much optimization should be performed. + +.. option:: -O<arg>, -O (equivalent to -O2), --optimize, --optimize=<arg> + +.. option:: -Ofast<arg> + +Debug information generation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Flags controlling how much and what kind of debug information should be +generated. + +Kind and level of debug information +----------------------------------- +.. option:: -g, --debug, --debug=<arg> + +Generate source-level debug information + +.. option:: -gdwarf-2 + +Generate source-level debug information with dwarf version 2 + +.. option:: -gdwarf-3 + +Generate source-level debug information with dwarf version 3 + +.. option:: -gdwarf-4, -gdwarf + +Generate source-level debug information with dwarf version 4 + +.. option:: -gdwarf-5 + +Generate source-level debug information with dwarf version 5 + +.. option:: -gfull + +.. option:: -gused + +Debug level +___________ +.. option:: -g0 + +.. option:: -g2 + +.. option:: -g3 + +.. option:: -ggdb0 + +.. option:: -ggdb1 + +.. option:: -ggdb2 + +.. option:: -ggdb3 + +.. option:: -gline-tables-only, -g1, -gmlt + +Emit debug line number tables only + +.. option:: -gmodules + +Generate debug info with external references to clang modules or precompiled headers + +Debugger to tune debug information for +______________________________________ +.. option:: -ggdb + +.. option:: -glldb + +.. option:: -gsce + +Debug information flags +----------------------- +.. option:: -gcolumn-info, -gno-column-info + +.. option:: -gdwarf-aranges + +.. option:: -ggnu-pubnames + +.. option:: -grecord-gcc-switches, -gno-record-gcc-switches + +.. option:: -gsplit-dwarf + +.. option:: -gstrict-dwarf, -gno-strict-dwarf + +Static analyzer flags +===================== + +Flags controlling the behavior of the Clang Static Analyzer. + +.. option:: -Xanalyzer <arg> + +Pass <arg> to the static analyzer + +Fortran compilation flags +========================= + +Flags that will be passed onto the ``gfortran`` compiler when Clang is given +a Fortran input. + +.. option:: -A<arg>, --assert <arg>, --assert=<arg> + +.. option:: -A-<arg> + +.. option:: -J<arg> + +.. option:: -cpp + +.. option:: -faggressive-function-elimination, -fno-aggressive-function-elimination + +.. option:: -falign-commons, -fno-align-commons + +.. option:: -fall-intrinsics, -fno-all-intrinsics + +.. option:: -fautomatic, -fno-automatic + +.. option:: -fbackslash, -fno-backslash + +.. option:: -fbacktrace, -fno-backtrace + +.. option:: -fblas-matmul-limit=<arg> + +.. option:: -fbounds-check, -fno-bounds-check + +.. option:: -fcheck-array-temporaries, -fno-check-array-temporaries + +.. option:: -fcheck=<arg> + +.. option:: -fcoarray=<arg> + +.. option:: -fconvert=<arg> + +.. option:: -fcray-pointer, -fno-cray-pointer + +.. option:: -fd-lines-as-code, -fno-d-lines-as-code + +.. option:: -fd-lines-as-comments, -fno-d-lines-as-comments + +.. option:: -fdefault-double-8, -fno-default-double-8 + +.. option:: -fdefault-integer-8, -fno-default-integer-8 + +.. option:: -fdefault-real-8, -fno-default-real-8 + +.. option:: -fdollar-ok, -fno-dollar-ok + +.. option:: -fdump-fortran-optimized, -fno-dump-fortran-optimized + +.. option:: -fdump-fortran-original, -fno-dump-fortran-original + +.. option:: -fdump-parse-tree, -fno-dump-parse-tree + +.. option:: -fexternal-blas, -fno-external-blas + +.. option:: -ff2c, -fno-f2c + +.. option:: -ffixed-form, -fno-fixed-form + +.. option:: -ffixed-line-length-<arg> + +.. option:: -ffpe-trap=<arg> + +.. option:: -ffree-form, -fno-free-form + +.. option:: -ffree-line-length-<arg> + +.. option:: -ffrontend-optimize, -fno-frontend-optimize + +.. option:: -fimplicit-none, -fno-implicit-none + +.. option:: -finit-character=<arg> + +.. option:: -finit-integer=<arg> + +.. option:: -finit-local-zero, -fno-init-local-zero + +.. option:: -finit-logical=<arg> + +.. option:: -finit-real=<arg> + +.. option:: -finteger-4-integer-8, -fno-integer-4-integer-8 + +.. option:: -fintrinsic-modules-path, -fno-intrinsic-modules-path + +.. option:: -fmax-array-constructor=<arg> + +.. option:: -fmax-errors=<arg> + +.. option:: -fmax-identifier-length, -fno-max-identifier-length + +.. option:: -fmax-stack-var-size=<arg> + +.. option:: -fmax-subrecord-length=<arg> + +.. option:: -fmodule-private, -fno-module-private + +.. option:: -fpack-derived, -fno-pack-derived + +.. option:: -fprotect-parens, -fno-protect-parens + +.. option:: -frange-check, -fno-range-check + +.. option:: -freal-4-real-10, -fno-real-4-real-10 + +.. option:: -freal-4-real-16, -fno-real-4-real-16 + +.. option:: -freal-4-real-8, -fno-real-4-real-8 + +.. option:: -freal-8-real-10, -fno-real-8-real-10 + +.. option:: -freal-8-real-16, -fno-real-8-real-16 + +.. option:: -freal-8-real-4, -fno-real-8-real-4 + +.. option:: -frealloc-lhs, -fno-realloc-lhs + +.. option:: -frecord-marker=<arg> + +.. option:: -frecursive, -fno-recursive + +.. option:: -frepack-arrays, -fno-repack-arrays + +.. option:: -fsecond-underscore, -fno-second-underscore + +.. option:: -fsign-zero, -fno-sign-zero + +.. option:: -fstack-arrays, -fno-stack-arrays + +.. option:: -funderscoring, -fno-underscoring + +.. option:: -fwhole-file, -fno-whole-file + +.. option:: -nocpp + +.. option:: -static-libgfortran + +Linker flags +============ +Flags that are passed on to the linker + +.. option:: -L<dir>, --library-directory <arg>, --library-directory=<arg> + +Add directory to library search path + +.. option:: -Mach + +.. option:: -T<script> + +Specify <script> as linker script + +.. option:: -Tbss<addr> + +Set starting address of BSS to <addr> + +.. option:: -Tdata<addr> + +Set starting address of BSS to <addr> + +.. option:: -Ttext<addr> + +Set starting address of BSS to <addr> + +.. option:: -Wl,<arg>,<arg2>... + +Pass the comma separated arguments in <arg> to the linker + +.. option:: -X + +.. option:: -Xlinker <arg>, --for-linker <arg>, --for-linker=<arg> + +Pass <arg> to the linker + +.. program:: clang1 +.. option:: -Z +.. program:: clang + +.. option:: -e<arg>, --entry + +.. option:: -filelist <arg> + +.. option:: -l<arg> + +.. option:: -r + +.. option:: -rpath <arg> + +.. option:: -s + +.. option:: -t + +.. option:: -u<arg>, --force-link <arg>, --force-link=<arg> + +.. option:: -undef + +undef all system defines + +.. option:: -undefined<arg>, --no-undefined + +.. option:: -z <arg> + +Pass -z <arg> to the linker + diff --git a/docs/ClangFormatStyleOptions.rst b/docs/ClangFormatStyleOptions.rst index 3f76da6dca32..ed628e370087 100644 --- a/docs/ClangFormatStyleOptions.rst +++ b/docs/ClangFormatStyleOptions.rst @@ -213,6 +213,20 @@ the configuration (without a prefix: ``Auto``). If ``true``, aligns escaped newlines as far left as possible. Otherwise puts them into the right-most column. + .. code-block:: c++ + + true: + #define A \ + int aaaa; \ + int b; \ + int dddddddddd; + + false: + #define A \ + int aaaa; \ + int b; \ + int dddddddddd; + **AlignOperands** (``bool``) If ``true``, horizontally align operands of binary and ternary expressions. @@ -228,10 +242,23 @@ the configuration (without a prefix: ``Auto``). **AlignTrailingComments** (``bool``) If ``true``, aligns trailing comments. + .. code-block:: c++ + + true: false: + int a; // My comment a vs. int a; // My comment a + int b = 2; // comment b int b = 2; // comment about b + **AllowAllParametersOfDeclarationOnNextLine** (``bool``) Allow putting all parameters of a function declaration onto the next line even if ``BinPackParameters`` is ``false``. + .. code-block:: c++ + + true: false: + myFunction(foo, vs. myFunction(foo, bar, plop); + bar, + plop); + **AllowShortBlocksOnASingleLine** (``bool``) Allows contracting simple braced statements to a single line. @@ -240,6 +267,17 @@ the configuration (without a prefix: ``Auto``). **AllowShortCaseLabelsOnASingleLine** (``bool``) If ``true``, short case labels will be contracted to a single line. + .. code-block:: c++ + + true: false: + switch (a) { vs. switch (a) { + case 1: x = 1; break; case 1: + case 2: return; x = 1; + } break; + case 2: + return; + } + **AllowShortFunctionsOnASingleLine** (``ShortFunctionStyle``) Dependent on the value, ``int f() { return 0; }`` can be put on a single line. @@ -252,12 +290,32 @@ the configuration (without a prefix: ``Auto``). * ``SFS_Empty`` (in configuration: ``Empty``) Only merge empty functions. + .. code-block:: c++ + + void f() { bar(); } + void f2() { + bar2(); + } + * ``SFS_Inline`` (in configuration: ``Inline``) Only merge functions defined inside a class. Implies "empty". + .. code-block:: c++ + + class Foo { + void f() { foo(); } + }; + * ``SFS_All`` (in configuration: ``All``) Merge all functions fitting on a single line. + .. code-block:: c++ + + class Foo { + void f() { foo(); } + }; + void f() { bar(); } + **AllowShortIfStatementsOnASingleLine** (``bool``) @@ -269,7 +327,7 @@ the configuration (without a prefix: ``Auto``). **AlwaysBreakAfterDefinitionReturnType** (``DefinitionReturnTypeBreakingStyle``) The function definition return type breaking style to use. This - option is deprecated and is retained for backwards compatibility. + option is **deprecated** and is retained for backwards compatibility. Possible values: @@ -294,18 +352,78 @@ the configuration (without a prefix: ``Auto``). Break after return type automatically. ``PenaltyReturnTypeOnItsOwnLine`` is taken into account. + .. code-block:: c++ + + class A { + int f() { return 0; }; + }; + int f(); + int f() { return 1; } + * ``RTBS_All`` (in configuration: ``All``) Always break after the return type. + .. code-block:: c++ + + class A { + int + f() { + return 0; + }; + }; + int + f(); + int + f() { + return 1; + } + * ``RTBS_TopLevel`` (in configuration: ``TopLevel``) Always break after the return types of top-level functions. + .. code-block:: c++ + + class A { + int f() { return 0; }; + }; + int + f(); + int + f() { + return 1; + } + * ``RTBS_AllDefinitions`` (in configuration: ``AllDefinitions``) Always break after the return type of function definitions. + .. code-block:: c++ + + class A { + int + f() { + return 0; + }; + }; + int f(); + int + f() { + return 1; + } + * ``RTBS_TopLevelDefinitions`` (in configuration: ``TopLevelDefinitions``) Always break after the return type of top-level definitions. + .. code-block:: c++ + + class A { + int f() { return 0; }; + }; + int f(); + int + f() { + return 1; + } + **AlwaysBreakBeforeMultilineStrings** (``bool``) @@ -316,18 +434,57 @@ the configuration (without a prefix: ``Auto``). the string at that point leads to it being indented ``ContinuationIndentWidth`` spaces from the start of the line. + .. code-block:: c++ + + true: false: + aaaa = vs. aaaa = "bbbb" + "bbbb" "cccc"; + "cccc"; + **AlwaysBreakTemplateDeclarations** (``bool``) If ``true``, always break after the ``template<...>`` of a template declaration. + .. code-block:: c++ + + true: false: + template <typename T> vs. template <typename T> class C {}; + class C {}; + **BinPackArguments** (``bool``) If ``false``, a function call's arguments will either be all on the same line or will have one line each. + .. code-block:: c++ + + true: + void f() { + f(aaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaa, + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa); + } + + false: + void f() { + f(aaaaaaaaaaaaaaaaaaaa, + aaaaaaaaaaaaaaaaaaaa, + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa); + } + **BinPackParameters** (``bool``) If ``false``, a function declaration's or function definition's parameters will either all be on the same line or will have one line each. + .. code-block:: c++ + + true: + void f(int aaaaaaaaaaaaaaaaaaaa, int aaaaaaaaaaaaaaaaaaaa, + int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {} + + false: + void f(int aaaaaaaaaaaaaaaaaaaa, + int aaaaaaaaaaaaaaaaaaaa, + int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {} + **BraceWrapping** (``BraceWrappingFlags``) Control of individual brace wrapping cases. @@ -336,22 +493,161 @@ the configuration (without a prefix: ``Auto``). Nested configuration flags: + * ``bool AfterClass`` Wrap class definitions. + + .. code-block:: c++ + + true: + class foo {}; + + false: + class foo + {}; + * ``bool AfterControlStatement`` Wrap control statements (``if``/``for``/``while``/``switch``/..). + + .. code-block:: c++ + + true: + if (foo()) + { + } else + {} + for (int i = 0; i < 10; ++i) + {} + + false: + if (foo()) { + } else { + } + for (int i = 0; i < 10; ++i) { + } + * ``bool AfterEnum`` Wrap enum definitions. + + .. code-block:: c++ + + true: + enum X : int + { + B + }; + + false: + enum X : int { B }; + * ``bool AfterFunction`` Wrap function definitions. + + .. code-block:: c++ + + true: + void foo() + { + bar(); + bar2(); + } + + false: + void foo() { + bar(); + bar2(); + } + * ``bool AfterNamespace`` Wrap namespace definitions. + + .. code-block:: c++ + + true: + namespace + { + int foo(); + int bar(); + } + + false: + namespace { + int foo(); + int bar(); + } + * ``bool AfterObjCDeclaration`` Wrap ObjC definitions (``@autoreleasepool``, interfaces, ..). + * ``bool AfterStruct`` Wrap struct definitions. + + .. code-block:: c++ + + true: + struct foo + { + int x; + } + + false: + struct foo { + int x; + } + * ``bool AfterUnion`` Wrap union definitions. + + .. code-block:: c++ + + true: + union foo + { + int x; + } + + false: + union foo { + int x; + } + * ``bool BeforeCatch`` Wrap before ``catch``. + + .. code-block:: c++ + + true: + try { + foo(); + } + catch () { + } + + false: + try { + foo(); + } catch () { + } + * ``bool BeforeElse`` Wrap before ``else``. + + .. code-block:: c++ + + true: + if (foo()) { + } + else { + } + + false: + if (foo()) { + } else { + } + * ``bool IndentBraces`` Indent the wrapped braces themselves. **BreakAfterJavaFieldAnnotations** (``bool``) Break after each annotation on a field in Java files. + .. code-block:: java + + true: false: + @Partial vs. @Partial @Mock DataLoad loader; + @Mock + DataLoad loader; + **BreakBeforeBinaryOperators** (``BinaryOperatorStyle``) The way to wrap binary operators. @@ -360,12 +656,45 @@ the configuration (without a prefix: ``Auto``). * ``BOS_None`` (in configuration: ``None``) Break after operators. + .. code-block:: c++ + + LooooooooooongType loooooooooooooooooooooongVariable = + someLooooooooooooooooongFunction(); + + bool value = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa == + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa && + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa > + ccccccccccccccccccccccccccccccccccccccccc; + * ``BOS_NonAssignment`` (in configuration: ``NonAssignment``) Break before operators that aren't assignments. + .. code-block:: c++ + + LooooooooooongType loooooooooooooooooooooongVariable = + someLooooooooooooooooongFunction(); + + bool value = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + == aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + && aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + > ccccccccccccccccccccccccccccccccccccccccc; + * ``BOS_All`` (in configuration: ``All``) Break before operators. + .. code-block:: c++ + + LooooooooooongType loooooooooooooooooooooongVariable + = someLooooooooooooooooongFunction(); + + bool value = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + == aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + && aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + > ccccccccccccccccccccccccccccccccccccccccc; + **BreakBeforeBraces** (``BraceBreakingStyle``) @@ -376,41 +705,190 @@ the configuration (without a prefix: ``Auto``). * ``BS_Attach`` (in configuration: ``Attach``) Always attach braces to surrounding context. + .. code-block:: c++ + + try { + foo(); + } catch () { + } + void foo() { bar(); } + class foo {}; + if (foo()) { + } else { + } + enum X : int { A, B }; + * ``BS_Linux`` (in configuration: ``Linux``) Like ``Attach``, but break before braces on function, namespace and class definitions. + .. code-block:: c++ + + try { + foo(); + } catch () { + } + void foo() { bar(); } + class foo + { + }; + if (foo()) { + } else { + } + enum X : int { A, B }; + * ``BS_Mozilla`` (in configuration: ``Mozilla``) Like ``Attach``, but break before braces on enum, function, and record definitions. + .. code-block:: c++ + + try { + foo(); + } catch () { + } + void foo() { bar(); } + class foo + { + }; + if (foo()) { + } else { + } + enum X : int { A, B }; + * ``BS_Stroustrup`` (in configuration: ``Stroustrup``) Like ``Attach``, but break before function definitions, ``catch``, and ``else``. + .. code-block:: c++ + + try { + foo(); + } catch () { + } + void foo() { bar(); } + class foo + { + }; + if (foo()) { + } else { + } + enum X : int + { + A, + B + }; + * ``BS_Allman`` (in configuration: ``Allman``) Always break before braces. + .. code-block:: c++ + + try { + foo(); + } + catch () { + } + void foo() { bar(); } + class foo { + }; + if (foo()) { + } + else { + } + enum X : int { A, B }; + * ``BS_GNU`` (in configuration: ``GNU``) Always break before braces and add an extra level of indentation to braces of control statements, not to those of class, function or other definitions. + .. code-block:: c++ + + try + { + foo(); + } + catch () + { + } + void foo() { bar(); } + class foo + { + }; + if (foo()) + { + } + else + { + } + enum X : int + { + A, + B + }; + * ``BS_WebKit`` (in configuration: ``WebKit``) Like ``Attach``, but break before functions. + .. code-block:: c++ + + try { + foo(); + } catch () { + } + void foo() { bar(); } + class foo { + }; + if (foo()) { + } else { + } + enum X : int { A, B }; + * ``BS_Custom`` (in configuration: ``Custom``) Configure each individual brace in `BraceWrapping`. +**BreakBeforeInheritanceComma** (``bool``) + If ``true``, in the class inheritance expression clang-format will + break before ``:`` and ``,`` if there is multiple inheritance. + + .. code-block:: c++ + + true: false: + class MyClass vs. class MyClass : public X, public Y { + : public X }; + , public Y { + }; + **BreakBeforeTernaryOperators** (``bool``) If ``true``, ternary operators will be placed after line breaks. + .. code-block:: c++ + + true: + veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongDescription + ? firstValue + : SecondValueVeryVeryVeryVeryLong; + + true: + veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongDescription ? + firstValue : + SecondValueVeryVeryVeryVeryLong; + **BreakConstructorInitializersBeforeComma** (``bool``) Always break constructor initializers before commas and align the commas with the colon. + .. code-block:: c++ + + true: false: + SomeClass::Constructor() vs. SomeClass::Constructor() : a(a), + : a(a) b(b), + , b(b) c(c) {} + , c(c) {} + **BreakStringLiterals** (``bool``) Allow breaking string literals when formatting. @@ -425,10 +903,31 @@ the configuration (without a prefix: ``Auto``). A regular expression that describes comments with special meaning, which should not be split into lines or otherwise changed. + .. code-block:: c++ + + // CommentPragmas: '^ FOOBAR pragma:' + // Will leave the following line unaffected + #include <vector> // FOOBAR pragma: keep + **ConstructorInitializerAllOnOneLineOrOnePerLine** (``bool``) If the constructor initializers don't fit on a line, put each initializer on its own line. + .. code-block:: c++ + + true: + SomeClass::Constructor() + : aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaa) { + return 0; + } + + false: + SomeClass::Constructor() + : aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaa), + aaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaa) { + return 0; + } + **ConstructorInitializerIndentWidth** (``unsigned``) The number of characters to use for indentation of constructor initializer lists. @@ -436,6 +935,14 @@ the configuration (without a prefix: ``Auto``). **ContinuationIndentWidth** (``unsigned``) Indent width for line continuations. + .. code-block:: c++ + + ContinuationIndentWidth: 2 + + int i = // VeryVeryVeryVeryVeryLongComment + longFunction( // Again a long comment + arg); + **Cpp11BracedListStyle** (``bool``) If ``true``, format braced lists as best suited for C++11 braced lists. @@ -451,10 +958,20 @@ the configuration (without a prefix: ``Auto``). the parentheses of a function call with that name. If there is no name, a zero-length name is assumed. + .. code-block:: c++ + + true: false: + vector<int> x{1, 2, 3, 4}; vs. vector<int> x{ 1, 2, 3, 4 }; + vector<T> x{{}, {}, {}, {}}; vector<T> x{ {}, {}, {}, {} }; + f(MyMap[{composite, key}]); f(MyMap[{ composite, key }]); + new int[3]{1, 2, 3}; new int[3]{ 1, 2, 3 }; + **DerivePointerAlignment** (``bool``) If ``true``, analyze the formatted file for the most common - alignment of ``&`` and ``\*``. ``PointerAlignment`` is then used only as - fallback. + alignment of ``&`` and ``*``. + Pointer and reference alignment styles are going to be updated according + to the preferences found in the file. + ``PointerAlignment`` is then used only as fallback. **DisableFormat** (``bool``) Disables formatting completely. @@ -471,6 +988,17 @@ the configuration (without a prefix: ``Auto``). NOTE: This is an experimental flag, that might go away or be renamed. Do not use this in config files, etc. Use at your own risk. +**FixNamespaceComments** (``bool``) + If ``true``, clang-format adds missing namespace end comments and + fixes invalid existing ones. + + .. code-block:: c++ + + true: false: + namespace a { vs. namespace a { + foo(); foo(); + } // namespace a; } + **ForEachMacros** (``std::vector<std::string>``) A vector of macros that should be interpreted as foreach loops instead of as function calls. @@ -516,7 +1044,7 @@ the configuration (without a prefix: ``Auto``). Priority: 2 - Regex: '^(<|"(gtest|isl|json)/)' Priority: 3 - - Regex: '.\*' + - Regex: '.*' Priority: 1 **IncludeIsMainRegex** (``std::string``) @@ -538,13 +1066,45 @@ the configuration (without a prefix: ``Auto``). When ``false``, use the same indentation level as for the switch statement. Switch statement body is always indented one level more than case labels. + .. code-block:: c++ + + false: true: + switch (fool) { vs. switch (fool) { + case 1: case 1: + bar(); bar(); + break; break; + default: default: + plop(); plop(); + } } + **IndentWidth** (``unsigned``) The number of columns to use for indentation. + .. code-block:: c++ + + IndentWidth: 3 + + void f() { + someFunction(); + if (true, false) { + f(); + } + } + **IndentWrappedFunctionNames** (``bool``) Indent if a function definition or declaration is wrapped after the type. + .. code-block:: c++ + + true: + LoooooooooooooooooooooooooooooooooooooooongReturnType + LoooooooooooooooooooooooooooooooongFunctionDeclaration(); + + false: + LoooooooooooooooooooooooooooooooooooooooongReturnType + LoooooooooooooooooooooooooooooooongFunctionDeclaration(); + **JavaScriptQuotes** (``JavaScriptQuoteStyle``) The JavaScriptQuoteStyle to use for JavaScript strings. @@ -553,16 +1113,54 @@ the configuration (without a prefix: ``Auto``). * ``JSQS_Leave`` (in configuration: ``Leave``) Leave string quotes as they are. + .. code-block:: js + + string1 = "foo"; + string2 = 'bar'; + * ``JSQS_Single`` (in configuration: ``Single``) Always use single quotes. + .. code-block:: js + + string1 = 'foo'; + string2 = 'bar'; + * ``JSQS_Double`` (in configuration: ``Double``) Always use double quotes. + .. code-block:: js + + string1 = "foo"; + string2 = "bar"; + + +**JavaScriptWrapImports** (``bool``) + Whether to wrap JavaScript import/export statements. + + .. code-block:: js + + true: + import { + VeryLongImportsAreAnnoying, + VeryLongImportsAreAnnoying, + VeryLongImportsAreAnnoying, + } from 'some/module.js' + + false: + import {VeryLongImportsAreAnnoying, VeryLongImportsAreAnnoying, VeryLongImportsAreAnnoying,} from "some/module.js" **KeepEmptyLinesAtTheStartOfBlocks** (``bool``) - If true, empty lines at the start of blocks are kept. + If true, the empty line at the start of blocks is kept. + + .. code-block:: c++ + + true: false: + if (foo) { vs. if (foo) { + bar(); + bar(); } + } **Language** (``LanguageKind``) Language, this format style is targeted at. @@ -573,7 +1171,7 @@ the configuration (without a prefix: ``Auto``). Do not use. * ``LK_Cpp`` (in configuration: ``Cpp``) - Should be used for C, C++, ObjectiveC, ObjectiveC++. + Should be used for C, C++. * ``LK_Java`` (in configuration: ``Java``) Should be used for Java. @@ -581,6 +1179,9 @@ the configuration (without a prefix: ``Auto``). * ``LK_JavaScript`` (in configuration: ``JavaScript``) Should be used for JavaScript. + * ``LK_ObjC`` (in configuration: ``ObjC``) + Should be used for Objective-C, Objective-C++. + * ``LK_Proto`` (in configuration: ``Proto``) Should be used for Protocol Buffers (https://developers.google.com/protocol-buffers/). @@ -593,12 +1194,49 @@ the configuration (without a prefix: ``Auto``). **MacroBlockBegin** (``std::string``) A regular expression matching macros that start a block. + .. code-block:: c++ + + # With: + MacroBlockBegin: "^NS_MAP_BEGIN|\ + NS_TABLE_HEAD$" + MacroBlockEnd: "^\ + NS_MAP_END|\ + NS_TABLE_.*_END$" + + NS_MAP_BEGIN + foo(); + NS_MAP_END + + NS_TABLE_HEAD + bar(); + NS_TABLE_FOO_END + + # Without: + NS_MAP_BEGIN + foo(); + NS_MAP_END + + NS_TABLE_HEAD + bar(); + NS_TABLE_FOO_END + **MacroBlockEnd** (``std::string``) A regular expression matching macros that end a block. **MaxEmptyLinesToKeep** (``unsigned``) The maximum number of consecutive empty lines to keep. + .. code-block:: c++ + + MaxEmptyLinesToKeep: 1 vs. MaxEmptyLinesToKeep: 0 + int f() { int f() { + int = 1; int i = 1; + i = foo(); + i = foo(); return i; + } + return i; + } + **NamespaceIndentation** (``NamespaceIndentationKind``) The indentation used for namespaces. @@ -607,17 +1245,52 @@ the configuration (without a prefix: ``Auto``). * ``NI_None`` (in configuration: ``None``) Don't indent in namespaces. + .. code-block:: c++ + + namespace out { + int i; + namespace in { + int i; + } + } + * ``NI_Inner`` (in configuration: ``Inner``) Indent only in inner namespaces (nested in other namespaces). + .. code-block:: c++ + + namespace out { + int i; + namespace in { + int i; + } + } + * ``NI_All`` (in configuration: ``All``) Indent in all namespaces. + .. code-block:: c++ + + namespace out { + int i; + namespace in { + int i; + } + } + **ObjCBlockIndentWidth** (``unsigned``) The number of characters to use for indentation of ObjC blocks. + .. code-block:: objc + + ObjCBlockIndentWidth: 4 + + [operation setCompletionBlock:^{ + [self onOperationDone]; + }]; + **ObjCSpaceAfterProperty** (``bool``) Add a space after ``@property`` in Objective-C, i.e. use ``@property (readonly)`` instead of ``@property(readonly)``. @@ -653,29 +1326,75 @@ the configuration (without a prefix: ``Auto``). * ``PAS_Left`` (in configuration: ``Left``) Align pointer to the left. + .. code-block:: c++ + + int* a; + * ``PAS_Right`` (in configuration: ``Right``) Align pointer to the right. + .. code-block:: c++ + + int *a; + * ``PAS_Middle`` (in configuration: ``Middle``) Align pointer in the middle. + .. code-block:: c++ + + int * a; + **ReflowComments** (``bool``) If ``true``, clang-format will attempt to re-flow comments. + .. code-block:: c++ + + false: + // veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongComment with plenty of information + /* second veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongComment with plenty of information */ + + true: + // veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongComment with plenty of + // information + /* second veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongComment with plenty of + * information */ + **SortIncludes** (``bool``) If ``true``, clang-format will sort ``#includes``. + .. code-block:: c++ + + false: true: + #include "b.h" vs. #include "a.h" + #include "a.h" #include "b.h" + **SpaceAfterCStyleCast** (``bool``) - If ``true``, a space may be inserted after C style casts. + If ``true``, a space is inserted after C style casts. + + .. code-block:: c++ + + true: false: + (int)i; vs. (int) i; **SpaceAfterTemplateKeyword** (``bool``) If ``true``, a space will be inserted after the 'template' keyword. + .. code-block:: c++ + + true: false: + template <int> void foo(); vs. template<int> void foo(); + **SpaceBeforeAssignmentOperators** (``bool``) If ``false``, spaces will be removed before assignment operators. + .. code-block:: c++ + + true: false: + int a = 5; vs. int a=5; + a += 42 a+=42; + **SpaceBeforeParens** (``SpaceBeforeParensOptions``) Defines in which cases to put a space before opening parentheses. @@ -684,21 +1403,55 @@ the configuration (without a prefix: ``Auto``). * ``SBPO_Never`` (in configuration: ``Never``) Never put a space before opening parentheses. + .. code-block:: c++ + + void f() { + if(true) { + f(); + } + } + * ``SBPO_ControlStatements`` (in configuration: ``ControlStatements``) Put a space before opening parentheses only after control statement keywords (``for/if/while...``). + .. code-block:: c++ + + void f() { + if (true) { + f(); + } + } + * ``SBPO_Always`` (in configuration: ``Always``) Always put a space before opening parentheses, except when it's prohibited by the syntax rules (in function-like macro definitions) or when determined by other style rules (after unary operators, opening parentheses, etc.) + .. code-block:: c++ + + void f () { + if (true) { + f (); + } + } + **SpaceInEmptyParentheses** (``bool``) If ``true``, spaces may be inserted into ``()``. + .. code-block:: c++ + + true: false: + void f( ) { vs. void f() { + int x[] = {foo( ), bar( )}; int x[] = {foo(), bar()}; + if (true) { if (true) { + f( ); f(); + } } + } } + **SpacesBeforeTrailingComments** (``unsigned``) The number of spaces before trailing line comments (``//`` - comments). @@ -707,22 +1460,60 @@ the configuration (without a prefix: ``Auto``). those commonly have different usage patterns and a number of special cases. + .. code-block:: c++ + + SpacesBeforeTrailingComments: 3 + void f() { + if (true) { // foo1 + f(); // bar + } // foo + } + **SpacesInAngles** (``bool``) If ``true``, spaces will be inserted after ``<`` and before ``>`` in template argument lists. + .. code-block:: c++ + + true: false: + static_cast< int >(arg); vs. static_cast<int>(arg); + std::function< void(int) > fct; std::function<void(int)> fct; + **SpacesInCStyleCastParentheses** (``bool``) If ``true``, spaces may be inserted into C style casts. + .. code-block:: c++ + + true: false: + x = ( int32 )y vs. x = (int32)y + **SpacesInContainerLiterals** (``bool``) If ``true``, spaces are inserted inside container literals (e.g. ObjC and Javascript array and dict literals). + .. code-block:: js + + true: false: + var arr = [ 1, 2, 3 ]; vs. var arr = [1, 2, 3]; + f({a : 1, b : 2, c : 3}); f({a: 1, b: 2, c: 3}); + **SpacesInParentheses** (``bool``) If ``true``, spaces will be inserted after ``(`` and before ``)``. + .. code-block:: c++ + + true: false: + t f( Deleted & ) & = delete; vs. t f(Deleted &) & = delete; + **SpacesInSquareBrackets** (``bool``) If ``true``, spaces will be inserted after ``[`` and before ``]``. + Lambdas or unspecified size array declarations will not be affected. + + .. code-block:: c++ + + true: false: + int a[ 5 ]; vs. int a[5]; + std::unique_ptr<int[]> foo() {} // Won't be affected **Standard** (``LanguageStandard``) Format compatible with this standard, e.g. use ``A<A<int> >`` @@ -734,7 +1525,8 @@ the configuration (without a prefix: ``Auto``). Use C++03-compatible syntax. * ``LS_Cpp11`` (in configuration: ``Cpp11``) - Use features of C++11 (e.g. ``A<A<int>>`` instead of ``A<A<int> >``). + Use features of C++11, C++14 and C++1z (e.g. ``A<A<int>>`` instead of + ``A<A<int> >``). * ``LS_Auto`` (in configuration: ``Auto``) Automatic detection based on the input. @@ -755,6 +1547,9 @@ the configuration (without a prefix: ``Auto``). * ``UT_ForIndentation`` (in configuration: ``ForIndentation``) Use tabs only for indentation. + * ``UT_ForContinuationAndIndentation`` (in configuration: ``ForContinuationAndIndentation``) + Use tabs only for line continuation and indentation. + * ``UT_Always`` (in configuration: ``Always``) Use tabs whenever we need to fill whitespace that spans at least from one tab stop to the next one. @@ -872,4 +1667,3 @@ The result is: r(); } } - diff --git a/docs/ControlFlowIntegrityDesign.rst b/docs/ControlFlowIntegrityDesign.rst index a9f0b28a95f5..69b72f9ea5b2 100644 --- a/docs/ControlFlowIntegrityDesign.rst +++ b/docs/ControlFlowIntegrityDesign.rst @@ -498,12 +498,100 @@ In non-PIE executables the address of an external function (taken from the main executable) is the address of that function’s PLT record in the main executable. This would break the CFI checks. +Backward-edge CFI for return statements (RCFI) +============================================== + +This section is a proposal. As of March 2017 it is not implemented. + +Backward-edge control flow (`RET` instructions) can be hijacked +via overwriting the return address (`RA`) on stack. +Various mitigation techniques (e.g. `SafeStack`_, `RFG`_, `Intel CET`_) +try to detect or prevent `RA` corruption on stack. + +RCFI enforces the expected control flow in several different ways described below. +RCFI heavily relies on LTO. + +Leaf Functions +-------------- +If `f()` is a leaf function (i.e. it has no calls +except maybe no-return calls) it can be called using a special calling convention +that stores `RA` in a dedicated register `R` before the `CALL` instruction. +`f()` does not spill `R` and does not use the `RET` instruction, +instead it uses the value in `R` to `JMP` to `RA`. + +This flavour of CFI is *precise*, i.e. the function is guaranteed to return +to the point exactly following the call. + +An alternative approach is to +copy `RA` from stack to `R` in the first instruction of `f()`, +then `JMP` to `R`. +This approach is simpler to implement (does not require changing the caller) +but weaker (there is a small window when `RA` is actually stored on stack). + + +Functions called once +--------------------- +Suppose `f()` is called in just one place in the program +(assuming we can verify this in LTO mode). +In this case we can replace the `RET` instruction with a `JMP` instruction +with the immediate constant for `RA`. +This will *precisely* enforce the return control flow no matter what is stored on stack. + +Another variant is to compare `RA` on stack with the known constant and abort +if they don't match; then `JMP` to the known constant address. + +Functions called in a small number of call sites +------------------------------------------------ +We may extend the above approach to cases where `f()` +is called more than once (but still a small number of times). +With LTO we know all possible values of `RA` and we check them +one-by-one (or using binary search) against the value on stack. +If the match is found, we `JMP` to the known constant address, otherwise abort. + +This protection is *near-precise*, i.e. it guarantees that the control flow will +be transferred to one of the valid return addresses for this function, +but not necessary to the point of the most recent `CALL`. + +General case +------------ +For functions called multiple times a *return jump table* is constructed +in the same manner as jump tables for indirect function calls (see above). +The correct jump table entry (or it's index) is passed by `CALL` to `f()` +(as an extra argument) and then spilled to stack. +The `RET` instruction is replaced with a load of the jump table entry, +jump table range check, and `JMP` to the jump table entry. + +This protection is also *near-precise*. + +Returns from functions called indirectly +---------------------------------------- + +If a function is called indirectly, the return jump table is constructed for the +equivalence class of functions instead of a single function. + +Cross-DSO calls +--------------- +Consider two instrumented DSOs, `A` and `B`. `A` defines `f()` and `B` calls it. + +This case will be handled similarly to the cross-DSO scheme using the slow path callback. + +Non-goals +--------- + +RCFI does not protect `RET` instructions: + * in non-instrumented DSOs, + * in instrumented DSOs for functions that are called from non-instrumented DSOs, + * embedded into other instructions (e.g. `0f4fc3 cmovg %ebx,%eax`). + +.. _SafeStack: https://clang.llvm.org/docs/SafeStack.html +.. _RFG: http://xlab.tencent.com/en/2016/11/02/return-flow-guard +.. _Intel CET: https://software.intel.com/en-us/blogs/2016/06/09/intel-release-new-technology-specifications-protect-rop-attacks Hardware support ================ We believe that the above design can be efficiently implemented in hardware. -A single new instruction added to an ISA would allow to perform the CFI check +A single new instruction added to an ISA would allow to perform the forward-edge CFI check with fewer bytes per check (smaller code size overhead) and potentially more efficiently. The current software-only instrumentation requires at least 32-bytes per check (on x86_64). @@ -540,7 +628,7 @@ The bit vector lookup is probably too complex for a hardware implementation. Jump(kFailedCheckTarget); } -An alternative and more compact enconding would not use `kFailedCheckTarget`, +An alternative and more compact encoding would not use `kFailedCheckTarget`, and will trap on check failure instead. This will allow us to fit the instruction into **8-9 bytes**. The cross-DSO checks will be performed by a trap handler and diff --git a/docs/DiagnosticsReference.rst b/docs/DiagnosticsReference.rst index 7294c3662027..d8c486fc3b3c 100644 --- a/docs/DiagnosticsReference.rst +++ b/docs/DiagnosticsReference.rst @@ -251,6 +251,28 @@ Some of the diagnostics controlled by this flag are enabled by default. Controls `-Wmost`_, `-Wparentheses`_, `-Wswitch`_, `-Wswitch-bool`_. +-Walloca-with-align-alignof +--------------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++--------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`second argument to \_\_builtin\_alloca\_with\_align is supposed to be in bits`| ++--------------------------------------------------------------------------------------------------------------------+ + + +-Wambiguous-delete +------------------ +This diagnostic is enabled by default. + +**Diagnostic text:** + ++------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`multiple suitable` |nbsp| :placeholder:`A` |nbsp| :diagtext:`functions for` |nbsp| :placeholder:`B`:diagtext:`; no 'operator delete' function will be invoked if initialization throws an exception`| ++------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + + -Wambiguous-ellipsis -------------------- This diagnostic is enabled by default. @@ -482,7 +504,24 @@ This diagnostic is enabled by default. -Wasm ----- -Synonym for `-Wasm-operand-widths`_. +This diagnostic is enabled by default. + +Controls `-Wasm-ignored-qualifier`_, `-Wasm-operand-widths`_. + + +-Wasm-ignored-qualifier +----------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++----------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`ignored` |nbsp| :placeholder:`A` |nbsp| :diagtext:`qualifier on asm`| ++----------------------------------------------------------------------------------------------------------+ + ++-------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`meaningless 'volatile' on asm outside function`| ++-------------------------------------------------------------------------------------+ -Wasm-operand-widths @@ -697,21 +736,6 @@ This diagnostic is enabled by default. +-------------------------------------------------------------------------------+ --Wbad-array-new-length ----------------------- -This diagnostic is enabled by default. - -**Diagnostic text:** - -+--------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`array is too large (`:placeholder:`A` |nbsp| :diagtext:`elements)`| -+--------------------------------------------------------------------------------------------------------+ - -+-------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`array size is negative`| -+-------------------------------------------------------------+ - - -Wbad-function-cast ------------------- **Diagnostic text:** @@ -768,9 +792,26 @@ This diagnostic is enabled by default. **Diagnostic text:** -+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`implicit truncation from` |nbsp| :placeholder:`C` |nbsp| :diagtext:`to bitfield changes value from` |nbsp| :placeholder:`A` |nbsp| :diagtext:`to` |nbsp| :placeholder:`B`| -+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`implicit truncation from` |nbsp| :placeholder:`C` |nbsp| :diagtext:`to bit-field changes value from` |nbsp| :placeholder:`A` |nbsp| :diagtext:`to` |nbsp| :placeholder:`B`| ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + + +-Wbitfield-enum-conversion +-------------------------- +**Diagnostic text:** + ++------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`bit-field` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is not wide enough to store all enumerators of` |nbsp| :placeholder:`B`| ++------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`signed bit-field` |nbsp| :placeholder:`A` |nbsp| :diagtext:`needs an extra bit to represent the largest positive enumerators of` |nbsp| :placeholder:`B`| ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + ++---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`assigning value of signed enum type` |nbsp| :placeholder:`B` |nbsp| :diagtext:`to unsigned bit-field` |nbsp| :placeholder:`A`:diagtext:`; negative enumerators of enum` |nbsp| :placeholder:`B` |nbsp| :diagtext:`will be converted to positive values`| ++---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ -Wbitfield-width @@ -807,6 +848,17 @@ This diagnostic is enabled by default. +-----------------------------------------------------------------------------------------------------------+ +-Wblock-capture-autoreleasing +----------------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++-----------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`block captures an autoreleasing out-parameter, which may result in use-after-free bugs`| ++-----------------------------------------------------------------------------------------------------------------------------+ + + -Wbool-conversion ----------------- This diagnostic is enabled by default. @@ -1306,7 +1358,13 @@ Synonym for `-Wc++14-extensions`_. -------------- This diagnostic is enabled by default. -Controls `-Wdeprecated-increment-bool`_, `-Wdeprecated-register`_. +Also controls `-Wdeprecated-increment-bool`_, `-Wdeprecated-register`_. + +**Diagnostic text:** + ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`mangled name of` |nbsp| :placeholder:`A` |nbsp| :diagtext:`will change in C++17 due to non-throwing exception specification in function signature`| ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ -Wc++1z-extensions @@ -1343,10 +1401,22 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :diagtext:`hexadecimal floating literals are a C++1z feature`| +----------------------------------------------------------------------------------------+ ++----------------------------------------+--------------------+-------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`'`|+------------------+|:diagtext:`' initialization statements are a C++1z extension`| +| ||:diagtext:`if` || | +| |+------------------+| | +| ||:diagtext:`switch`|| | +| |+------------------+| | ++----------------------------------------+--------------------+-------------------------------------------------------------+ + +-----------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`inline variables are a C++1z extension`| +-----------------------------------------------------------------------------+ ++---------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`use of multiple declarators in a single using declaration is a C++1z extension`| ++---------------------------------------------------------------------------------------------------------------------+ + +-------------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`nested namespace definition is a C++1z extension; define each namespace separately`| +-------------------------------------------------------------------------------------------------------------------------+ @@ -1367,6 +1437,10 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :diagtext:`default scope specifier for attributes is a C++1z extension`| +--------------------------------------------------------------------------------------------------+ ++-----------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`pack expansion of using declaration is a C++1z extension`| ++-----------------------------------------------------------------------------------------------+ + -Wc++98-c++11-c++14-compat -------------------------- @@ -1396,6 +1470,14 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :diagtext:`pack fold expression is incompatible with C++ standards before C++1z`| +-----------------------------------------------------------------------------------------------------------+ ++---------------------------+--------------------+----------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| |+------------------+| |nbsp| :diagtext:`initialization statements are incompatible with C++ standards before C++1z`| +| ||:diagtext:`if` || | +| |+------------------+| | +| ||:diagtext:`switch`|| | +| |+------------------+| | ++---------------------------+--------------------+----------------------------------------------------------------------------------------------+ + +--------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`inline variables are incompatible with C++ standards before C++1z`| +--------------------------------------------------------------------------------------------------------+ @@ -1412,6 +1494,10 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :diagtext:`static\_assert with no message is incompatible with C++ standards before C++1z`| +---------------------------------------------------------------------------------------------------------------------+ ++-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`non-type template parameters declared with` |nbsp| :placeholder:`A` |nbsp| :diagtext:`are incompatible with C++ standards before C++1z`| ++-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + +-----------------------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`template template parameter using 'typename' is incompatible with C++ standards before C++1z`| +-----------------------------------------------------------------------------------------------------------------------------------+ @@ -1424,6 +1510,14 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :diagtext:`default scope specifier for attributes is incompatible with C++ standards before C++1z`| +-----------------------------------------------------------------------------------------------------------------------------+ ++------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`use of multiple declarators in a single using declaration is incompatible with C++ standards before C++1z`| ++------------------------------------------------------------------------------------------------------------------------------------------------+ + ++-----------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`pack expansion using declaration is incompatible with C++ standards before C++1z`| ++-----------------------------------------------------------------------------------------------------------------------+ + +----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`'begin' and 'end' returning different types (`:placeholder:`A` |nbsp| :diagtext:`and` |nbsp| :placeholder:`B`:diagtext:`) is incompatible with C++ standards before C++1z`| +----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ @@ -1436,7 +1530,7 @@ Also controls `-Wc++98-c++11-c++14-compat`_. **Diagnostic text:** +---------------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`hexidecimal floating literals are incompatible with C++ standards before C++1z`| +|:warning:`warning:` |nbsp| :diagtext:`hexadecimal floating literals are incompatible with C++ standards before C++1z`| +---------------------------------------------------------------------------------------------------------------------+ @@ -2176,10 +2270,6 @@ This diagnostic is enabled by default. |:warning:`warning:` |nbsp| :diagtext:`comparison of distinct pointer types`| +---------------------------------------------------------------------------+ -+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`comparison of distinct pointer types (`:placeholder:`A` |nbsp| :diagtext:`and` |nbsp| :placeholder:`B`:diagtext:`) uses non-standard composite pointer type` |nbsp| :placeholder:`C`| -+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ - -Wcomplex-component-init ------------------------ @@ -2309,7 +2399,7 @@ This diagnostic is enabled by default. ------------ Some of the diagnostics controlled by this flag are enabled by default. -Also controls `-Wbool-conversion`_, `-Wconstant-conversion`_, `-Wenum-conversion`_, `-Wfloat-conversion`_, `-Wint-conversion`_, `-Wliteral-conversion`_, `-Wnon-literal-null-conversion`_, `-Wnull-conversion`_, `-Wobjc-literal-conversion`_, `-Wshorten-64-to-32`_, `-Wsign-conversion`_, `-Wstring-conversion`_. +Also controls `-Wbitfield-enum-conversion`_, `-Wbool-conversion`_, `-Wconstant-conversion`_, `-Wenum-conversion`_, `-Wfloat-conversion`_, `-Wint-conversion`_, `-Wliteral-conversion`_, `-Wnon-literal-null-conversion`_, `-Wnull-conversion`_, `-Wobjc-literal-conversion`_, `-Wshorten-64-to-32`_, `-Wsign-conversion`_, `-Wstring-conversion`_. **Diagnostic text:** @@ -2343,15 +2433,15 @@ Also controls `-Wbool-conversion`_, `-Wconstant-conversion`_, `-Wenum-conversion Synonym for `-Wnull-conversion`_. --Wcoreturn-without-coawait --------------------------- +-Wcoroutine +----------- This diagnostic is enabled by default. **Diagnostic text:** -+--------------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`'co\_return' used in a function that uses neither 'co\_await' nor 'co\_yield'`| -+--------------------------------------------------------------------------------------------------------------------+ ++-----------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is required to declare the member 'unhandled\_exception()' when exceptions are enabled`| ++-----------------------------------------------------------------------------------------------------------------------------------------------------+ -Wcovered-switch-default @@ -2390,6 +2480,10 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :placeholder:`A` |nbsp| :diagtext:`attribute parameter` |nbsp| :placeholder:`B` |nbsp| :diagtext:`is negative and will be ignored`| +-------------------------------------------------------------------------------------------------------------------------------------------------------------+ ++---------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`nvcc does not allow '\_\_`:placeholder:`A`:diagtext:`\_\_' to appear after '()' in lambdas`| ++---------------------------------------------------------------------------------------------------------------------------------+ + +------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`ignored 'inline' attribute on kernel function` |nbsp| :placeholder:`A`| +------------------------------------------------------------------------------------------------------------+ @@ -2558,7 +2652,7 @@ Some of the diagnostics controlled by this flag are enabled by default. ------------ Some of the diagnostics controlled by this flag are enabled by default. -Also controls `-Wdeprecated-attributes`_, `-Wdeprecated-declarations`_, `-Wdeprecated-increment-bool`_, `-Wdeprecated-register`_, `-Wdeprecated-writable-strings`_. +Also controls `-Wdeprecated-attributes`_, `-Wdeprecated-declarations`_, `-Wdeprecated-dynamic-exception-spec`_, `-Wdeprecated-increment-bool`_, `-Wdeprecated-register`_, `-Wdeprecated-writable-strings`_. **Diagnostic text:** @@ -2596,10 +2690,6 @@ Also controls `-Wdeprecated-attributes`_, `-Wdeprecated-declarations`_, `-Wdepre |:warning:`warning:` |nbsp| :diagtext:`treating '`:placeholder:`A`:diagtext:`' input as '`:placeholder:`B`:diagtext:`' when in C++ mode, this behavior is deprecated`| +--------------------------------------------------------------------------------------------------------------------------------------------------------------------+ -+--------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`dynamic exception specifications are deprecated`| -+--------------------------------------------------------------------------------------+ - +-----------------------------------------------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`OpenCL version` |nbsp| :placeholder:`A` |nbsp| :diagtext:`does not support the option '`:placeholder:`B`:diagtext:`'`| +-----------------------------------------------------------------------------------------------------------------------------------------------------------+ @@ -2647,6 +2737,15 @@ This diagnostic is enabled by default. +-------------------------------------------------------------------------------------------------------------------------------------+ +-Wdeprecated-dynamic-exception-spec +----------------------------------- +**Diagnostic text:** + ++--------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`dynamic exception specifications are deprecated`| ++--------------------------------------------------------------------------------------+ + + -Wdeprecated-implementations ---------------------------- **Diagnostic text:** @@ -3089,6 +3188,17 @@ This diagnostic is enabled by default. +-----------------------------------------------------------------------------------------------------------------------------------+ +-Wduplicate-protocol +-------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++-----------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`duplicate protocol definition of` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is ignored`| ++-----------------------------------------------------------------------------------------------------------------------------+ + + -Wdynamic-class-memaccess ------------------------- This diagnostic is enabled by default. @@ -3108,6 +3218,19 @@ This diagnostic is enabled by default. +---------------------------+-------------------------------+------------------------------------------------------------------------------------------------+----------------------------------------+---------------------------------------------------------------------------------------------+-------------------------+ +-Wdynamic-exception-spec +------------------------ +Some of the diagnostics controlled by this flag are enabled by default. + +Also controls `-Wdeprecated-dynamic-exception-spec`_. + +**Diagnostic text:** + ++--------------------------------------------------------------------------------------------+ +|:error:`error:` |nbsp| :diagtext:`ISO C++1z does not allow dynamic exception specifications`| ++--------------------------------------------------------------------------------------------+ + + -Weffc++ -------- Synonym for `-Wnon-virtual-dtor`_. @@ -3328,7 +3451,13 @@ This diagnostic is enabled by default. ------- Some of the diagnostics controlled by this flag are enabled by default. -Controls `-Wignored-qualifiers`_, `-Winitializer-overrides`_, `-Wmissing-field-initializers`_, `-Wmissing-method-return-type`_, `-Wsemicolon-before-method-body`_, `-Wsign-compare`_, `-Wunused-parameter`_. +Also controls `-Wignored-qualifiers`_, `-Winitializer-overrides`_, `-Wmissing-field-initializers`_, `-Wmissing-method-return-type`_, `-Wsemicolon-before-method-body`_, `-Wsign-compare`_, `-Wunused-parameter`_. + +**Diagnostic text:** + ++-----------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`call to function without interrupt attribute could clobber interruptee's VFP registers`| ++-----------------------------------------------------------------------------------------------------------------------------+ -Wextra-qualification @@ -3498,6 +3627,10 @@ Also controls `-Wformat-extra-args`_, `-Wformat-invalid-specifier`_, `-Wformat-s **Diagnostic text:** ++-------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`using '%%P' format specifier without precision`| ++-------------------------------------------------------------------------------------+ + +---------------------------+----------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| |+--------------------------------------------+| |nbsp| :diagtext:`'`:placeholder:`A`:diagtext:`' should not be used as format arguments; add an explicit cast to` |nbsp| :placeholder:`B` |nbsp| :diagtext:`instead`| | ||:diagtext:`values of type` || | @@ -3514,6 +3647,10 @@ Also controls `-Wformat-extra-args`_, `-Wformat-invalid-specifier`_, `-Wformat-s | |+---------------------------+| | +------------------------------------------------------------------------------------------------------------------------------------+-----------------------------+------------------------+ ++----------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`using '`:placeholder:`A`:diagtext:`' format specifier annotation outside of os\_log()/os\_trace()`| ++----------------------------------------------------------------------------------------------------------------------------------------+ + +-----------------------------------------------------------------------------+-----------------------------+ |:warning:`warning:` |nbsp| :diagtext:`invalid position specified for` |nbsp| |+---------------------------+| | ||:diagtext:`field width` || @@ -3756,6 +3893,10 @@ Some of the diagnostics controlled by this flag are enabled by default. **Diagnostic text:** ++--------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`'diagnose\_if' is a clang extension`| ++--------------------------------------------------------------------------+ + +------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`'enable\_if' is a clang extension`| +------------------------------------------------------------------------+ @@ -4268,6 +4409,8 @@ This diagnostic is enabled by default. | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`variables and functions` || | |+----------------------------------------------------------------------------------------------------------------+| +| ||:diagtext:`functions and global variables` || +| |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`functions, variables, and Objective-C interfaces` || | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`functions and methods` || @@ -4280,6 +4423,8 @@ This diagnostic is enabled by default. | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`functions, methods, and parameters` || | |+----------------------------------------------------------------------------------------------------------------+| +| ||:diagtext:`functions, methods, and global variables` || +| |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`classes` || | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`enums` || @@ -4326,7 +4471,7 @@ This diagnostic is enabled by default. | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`variables with static or thread storage duration` || | |+----------------------------------------------------------------------------------------------------------------+| -| ||:diagtext:`functions and global variables` || +| ||:diagtext:`functions, methods, properties, and global variables` || | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`structs, unions, and typedefs` || | |+----------------------------------------------------------------------------------------------------------------+| @@ -4346,6 +4491,10 @@ This diagnostic is enabled by default. | |+----------------------------------------------------------------------------------------------------------------+| | ||:diagtext:`variables, functions, methods, types, enumerations, enumerators, labels, and non-static data members`|| | |+----------------------------------------------------------------------------------------------------------------+| +| ||:diagtext:`classes and enumerations` || +| |+----------------------------------------------------------------------------------------------------------------+| +| ||:diagtext:`named declarations` || +| |+----------------------------------------------------------------------------------------------------------------+| +------------------------------------------------------------------------------------------------+------------------------------------------------------------------------------------------------------------------+ +--------------------------------------------------------------------------------------------------------------------------------------------------------+ @@ -4516,10 +4665,27 @@ This diagnostic is enabled by default. +--------------------------------------------------------------------------------------------------------+ +-Wignored-pragma-intrinsic +-------------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++------------------------------------------------------------------------------------------+------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is not a recognized builtin`|+----------------------------------------------------------------------------+| +| || || +| |+----------------------------------------------------------------------------+| +| ||:diagtext:`; consider including <intrin.h> to access non-builtin intrinsics`|| +| |+----------------------------------------------------------------------------+| ++------------------------------------------------------------------------------------------+------------------------------------------------------------------------------+ + + -Wignored-pragmas ----------------- This diagnostic is enabled by default. +Also controls `-Wignored-pragma-intrinsic`_. + **Diagnostic text:** +------------------------------------------------------------------------------+---------------------------+-----------------------+ @@ -4538,6 +4704,10 @@ This diagnostic is enabled by default. | |+-------------------------+| | +-----------------------------------------------------------------------------------+---------------------------+-----------------------+ ++-----------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`OpenCL extension end directive mismatches begin directive - ignoring`| ++-----------------------------------------------------------------------------------------------------------+ + +----------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`'#pragma comment` |nbsp| :placeholder:`A`:diagtext:`' ignored`| +----------------------------------------------------------------------------------------------------+ @@ -4562,10 +4732,6 @@ This diagnostic is enabled by default. |:warning:`warning:` |nbsp| :diagtext:`missing ':' or ')' after` |nbsp| :placeholder:`A` |nbsp| :diagtext:`- ignoring`| +---------------------------------------------------------------------------------------------------------------------+ -+--------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`expected 'enable' or 'disable' - ignoring`| -+--------------------------------------------------------------------------------+ - +---------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`expected identifier in '#pragma` |nbsp| :placeholder:`A`:diagtext:`' - ignored`| +---------------------------------------------------------------------------------------------------------------------+ @@ -4586,6 +4752,14 @@ This diagnostic is enabled by default. |:warning:`warning:` |nbsp| :diagtext:`expected non-wide string literal in '#pragma` |nbsp| :placeholder:`A`:diagtext:`'`| +------------------------------------------------------------------------------------------------------------------------+ ++-------------------------------------------------------+---------------------------------------------------+------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`expected` |nbsp| |+-------------------------------------------------+| |nbsp| :diagtext:`- ignoring`| +| ||:diagtext:`'enable', 'disable', 'begin' or 'end'`|| | +| |+-------------------------------------------------+| | +| ||:diagtext:`'disable'` || | +| |+-------------------------------------------------+| | ++-------------------------------------------------------+---------------------------------------------------+------------------------------+ + +-----------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`expected ')' or ',' in '#pragma` |nbsp| :placeholder:`A`:diagtext:`'`| +-----------------------------------------------------------------------------------------------------------+ @@ -4610,18 +4784,14 @@ This diagnostic is enabled by default. |:warning:`warning:` |nbsp| :diagtext:`extra tokens at end of '#pragma` |nbsp| :placeholder:`A`:diagtext:`' - ignored`| +---------------------------------------------------------------------------------------------------------------------+ ++----------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`incorrect use of #pragma clang force\_cuda\_host\_device begin\|end`| ++----------------------------------------------------------------------------------------------------------+ + +-------------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`'#pragma init\_seg' is only supported when targeting a Microsoft environment`| +-------------------------------------------------------------------------------------------------------------------+ -+------------------------------------------------------------------------------------------+------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is not a recognized builtin`|+----------------------------------------------------------------------------+| -| || || -| |+----------------------------------------------------------------------------+| -| ||:diagtext:`; consider including <intrin.h> to access non-builtin intrinsics`|| -| |+----------------------------------------------------------------------------+| -+------------------------------------------------------------------------------------------+------------------------------------------------------------------------------+ - +-----------------------------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`unknown action for '#pragma` |nbsp| :placeholder:`A`:diagtext:`' - ignored`| +-----------------------------------------------------------------------------------------------------------------+ @@ -4894,6 +5064,25 @@ This diagnostic is enabled by default. +----------------------------------------------------------------------------+ +-Wincompatible-exception-spec +----------------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++--------------------------------------------------------------------------+----------------------+--------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`exception specifications of` |nbsp| |+--------------------+| |nbsp| :diagtext:`types differ`| +| ||:diagtext:`return` || | +| |+--------------------+| | +| ||:diagtext:`argument`|| | +| |+--------------------+| | ++--------------------------------------------------------------------------+----------------------+--------------------------------+ + ++-----------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`target exception specification is not superset of source`| ++-----------------------------------------------------------------------------------------------+ + + -Wincompatible-function-pointer-types ------------------------------------- This diagnostic is enabled by default. @@ -5081,6 +5270,15 @@ This diagnostic is enabled by default. +------------------------------------------------------------------------------------------------------------------------------------+ +-Winconsistent-missing-destructor-override +------------------------------------------ +**Diagnostic text:** + ++------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :placeholder:`A` |nbsp| :diagtext:`overrides a destructor but is not marked 'override'`| ++------------------------------------------------------------------------------------------------------------------+ + + -Winconsistent-missing-override ------------------------------- This diagnostic is enabled by default. @@ -5133,6 +5331,21 @@ This diagnostic is enabled by default. +---------------------------------------------------------------------------------------------------------------------------------------+ +-Winjected-class-name +--------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---------------------------+--------------------------------------------------------------+------------------------+---------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`ISO C++ specifies that qualified reference to` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is a constructor name rather than a` |nbsp| |+-------------------------+| |nbsp| :diagtext:`in this context, despite preceding` |nbsp| |+----------------------+| |nbsp| :diagtext:`keyword`| +| ||:diagtext:`template name`|| ||:diagtext:`'typename'`|| | +| |+-------------------------+| |+----------------------+| | +| ||:diagtext:`type` || ||:diagtext:`'template'`|| | +| |+-------------------------+| |+----------------------+| | ++---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---------------------------+--------------------------------------------------------------+------------------------+---------------------------+ + + -Winline -------- This diagnostic flag exists for GCC compatibility, and has no effect in Clang. @@ -5354,6 +5567,21 @@ Some of the diagnostics controlled by this flag are enabled by default. +------------------------------------------------------------------------------------------------------------------------------------------------------------+ +-Winvalid-partial-specialization +-------------------------------- +This diagnostic is an error by default, but the flag ``-Wno-invalid-partial-specialization`` can be used to disable the error. + +**Diagnostic text:** + ++-----------------------+----------------------+-----------------------------------------------------------------------------------------------------+ +|:error:`error:` |nbsp| |+--------------------+| |nbsp| :diagtext:`template partial specialization is not more specialized than the primary template`| +| ||:diagtext:`class` || | +| |+--------------------+| | +| ||:diagtext:`variable`|| | +| |+--------------------+| | ++-----------------------+----------------------+-----------------------------------------------------------------------------------------------------+ + + -Winvalid-pch ------------- This diagnostic flag exists for GCC compatibility, and has no effect in Clang. @@ -5475,14 +5703,7 @@ This diagnostic is enabled by default. -Wliblto -------- -This diagnostic is enabled by default. - -**Diagnostic text:** - -+-------------------------------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`libLTO.dylib relative to clang installed dir not found; using 'ld' default search path instead`| -+-------------------------------------------------------------------------------------------------------------------------------------+ - +This diagnostic flag exists for GCC compatibility, and has no effect in Clang. -Wliteral-conversion -------------------- @@ -5529,9 +5750,13 @@ This diagnostic is enabled by default. **Diagnostic text:** -+-----------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`logical not is only applied to the left hand side of this comparison`| -+-----------------------------------------------------------------------------------------------------------+ ++--------------------------------------------------------------------------------------------------------+------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`logical not is only applied to the left hand side of this` |nbsp| |+----------------------------+| +| ||:diagtext:`comparison` || +| |+----------------------------+| +| ||:diagtext:`bitwise operator`|| +| |+----------------------------+| ++--------------------------------------------------------------------------------------------------------+------------------------------+ -Wlogical-op-parentheses @@ -5598,6 +5823,10 @@ Some of the diagnostics controlled by this flag are enabled by default. |:warning:`warning:` |nbsp| :diagtext:`variable named 'main' with external linkage has undefined behavior`| +---------------------------------------------------------------------------------------------------------+ ++------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`bool literal returned from 'main'`| ++------------------------------------------------------------------------+ + +---------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`'main' should not be declared static`| +---------------------------------------------------------------------------+ @@ -5636,6 +5865,21 @@ This diagnostic is enabled by default. +--------------------------------------------------------------------------------+ +-Wmax-unsigned-zero +------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++----------------------------------------------------------------+---------------------------------------+------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`taking the max of` |nbsp| |+-------------------------------------+| |nbsp| :diagtext:`is always equal to the other value`| +| ||:diagtext:`a value and unsigned zero`|| | +| |+-------------------------------------+| | +| ||:diagtext:`unsigned zero and a value`|| | +| |+-------------------------------------+| | ++----------------------------------------------------------------+---------------------------------------+------------------------------------------------------+ + + -Wmemsize-comparison -------------------- This diagnostic is enabled by default. @@ -6269,6 +6513,14 @@ This diagnostic is enabled by default. |:remark:`remark:` |nbsp| :diagtext:`finished building module '`:placeholder:`A`:diagtext:`'`| +--------------------------------------------------------------------------------------------+ ++-----------------------------------------------------------------------------------------------------------------------------------+ +|:remark:`remark:` |nbsp| :diagtext:`could not acquire lock file for module '`:placeholder:`A`:diagtext:`':` |nbsp| :placeholder:`B`| ++-----------------------------------------------------------------------------------------------------------------------------------+ + ++---------------------------------------------------------------------------------------------------------------------+ +|:remark:`remark:` |nbsp| :diagtext:`timed out waiting to acquire lock file for module '`:placeholder:`A`:diagtext:`'`| ++---------------------------------------------------------------------------------------------------------------------+ + -Wmodule-conflict ----------------- @@ -6280,6 +6532,10 @@ This diagnostic is enabled by default. |:warning:`warning:` |nbsp| :diagtext:`module '`:placeholder:`A`:diagtext:`' conflicts with already-imported module '`:placeholder:`B`:diagtext:`':` |nbsp| :placeholder:`C`| +---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`module file '`:placeholder:`A`:diagtext:`' was validated as a system module and is now being imported as a non-system module; any difference in diagnostic options will be ignored`| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + -Wmodule-file-config-mismatch ----------------------------- @@ -6340,7 +6596,7 @@ This diagnostic is an error by default, but the flag ``-Wno-modules-import-neste ------ Some of the diagnostics controlled by this flag are enabled by default. -Controls `-Wcast-of-sel-type`_, `-Wchar-subscripts`_, `-Wcomment`_, `-Wdelete-non-virtual-dtor`_, `-Wextern-c-compat`_, `-Wfor-loop-analysis`_, `-Wformat`_, `-Wimplicit`_, `-Winfinite-recursion`_, `-Wmismatched-tags`_, `-Wmissing-braces`_, `-Wmove`_, `-Wmultichar`_, `-Wobjc-designated-initializers`_, `-Wobjc-missing-super-calls`_, `-Woverloaded-virtual`_, `-Wprivate-extern`_, `-Wreorder`_, `-Wreturn-type`_, `-Wself-assign`_, `-Wself-move`_, `-Wsizeof-array-argument`_, `-Wsizeof-array-decay`_, `-Wstring-plus-int`_, `-Wtrigraphs`_, `-Wuninitialized`_, `-Wunknown-pragmas`_, `-Wunused`_, `-Wvolatile-register-var`_. +Controls `-Wcast-of-sel-type`_, `-Wchar-subscripts`_, `-Wcomment`_, `-Wdelete-non-virtual-dtor`_, `-Wextern-c-compat`_, `-Wfor-loop-analysis`_, `-Wformat`_, `-Wimplicit`_, `-Winfinite-recursion`_, `-Wmismatched-tags`_, `-Wmissing-braces`_, `-Wmove`_, `-Wmultichar`_, `-Wobjc-designated-initializers`_, `-Wobjc-missing-super-calls`_, `-Woverloaded-virtual`_, `-Wprivate-extern`_, `-Wreorder`_, `-Wreturn-type`_, `-Wself-assign`_, `-Wself-move`_, `-Wsizeof-array-argument`_, `-Wsizeof-array-decay`_, `-Wstring-plus-int`_, `-Wtrigraphs`_, `-Wuninitialized`_, `-Wunknown-pragmas`_, `-Wunused`_, `-Wuser-defined-warnings`_, `-Wvolatile-register-var`_. -Wmove @@ -6353,6 +6609,17 @@ Controls `-Wpessimizing-move`_, `-Wredundant-move`_, `-Wself-move`_. Synonym for `-Wmicrosoft-include`_. +-Wmsvc-not-found +---------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++-------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`unable to find a Visual Studio installation; try running Clang from a developer command prompt`| ++-------------------------------------------------------------------------------------------------------------------------------------+ + + -Wmultichar ----------- This diagnostic is enabled by default. @@ -6447,9 +6714,9 @@ This diagnostic is enabled by default. ----------------------------------------- **Diagnostic text:** -+---------------------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`include of non-modular header inside framework module '`:placeholder:`A`:diagtext:`'`| -+---------------------------------------------------------------------------------------------------------------------------+ ++-----------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`include of non-modular header inside framework module '`:placeholder:`A`:diagtext:`': '`:placeholder:`B`:diagtext:`'`| ++-----------------------------------------------------------------------------------------------------------------------------------------------------------+ -Wnon-modular-include-in-module @@ -6458,9 +6725,9 @@ Also controls `-Wnon-modular-include-in-framework-module`_. **Diagnostic text:** -+-----------------------------------------------------------------------------------------------------------------+ -|:warning:`warning:` |nbsp| :diagtext:`include of non-modular header inside module '`:placeholder:`A`:diagtext:`'`| -+-----------------------------------------------------------------------------------------------------------------+ ++-------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`include of non-modular header inside module '`:placeholder:`A`:diagtext:`': '`:placeholder:`B`:diagtext:`'`| ++-------------------------------------------------------------------------------------------------------------------------------------------------+ -Wnon-pod-varargs @@ -6668,6 +6935,8 @@ This diagnostic is enabled by default. -------------------------- This diagnostic is enabled by default. +Also controls `-Wnullability-completeness-on-arrays`_. + **Diagnostic text:** +---------------------------+----------------------------+-----------------------------------------------------------------------------------------------------------+ @@ -6681,6 +6950,17 @@ This diagnostic is enabled by default. +---------------------------+----------------------------+-----------------------------------------------------------------------------------------------------------+ +-Wnullability-completeness-on-arrays +------------------------------------ +This diagnostic is enabled by default. + +**Diagnostic text:** + ++----------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`array parameter is missing a nullability type specifier (\_Nonnull, \_Nullable, or \_Null\_unspecified)`| ++----------------------------------------------------------------------------------------------------------------------------------------------+ + + -Wnullability-declspec ---------------------- This diagnostic is an error by default, but the flag ``-Wno-nullability-declspec`` can be used to disable the error. @@ -6711,6 +6991,21 @@ This diagnostic is an error by default, but the flag ``-Wno-nullability-declspec +---------------------------------------------------------------------------------------------------------------------------------+ +-Wnullability-inferred-on-nested-type +------------------------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++--------------------------------------------------------------------------------------------+-----------------------+---------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`inferring '\_Nonnull' for pointer type within` |nbsp| |+---------------------+| |nbsp| :diagtext:`is deprecated`| +| ||:diagtext:`array` || | +| |+---------------------+| | +| ||:diagtext:`reference`|| | +| |+---------------------+| | ++--------------------------------------------------------------------------------------------+-----------------------+---------------------------------+ + + -Wnullable-to-nonnull-conversion -------------------------------- **Diagnostic text:** @@ -7113,6 +7408,23 @@ This diagnostic is enabled by default. +-------------------------------------------------------------------------------------------------------------------------+ +-Wobjc-unsafe-perform-selector +------------------------------ +This diagnostic is enabled by default. + +**Diagnostic text:** + ++-------------------------------------------------------------------------------------------------------------------+--------------------+------------------------+ +|:warning:`warning:` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is incompatible with selectors that return a` |nbsp| |+------------------+| |nbsp| :diagtext:`type`| +| ||:diagtext:`struct`|| | +| |+------------------+| | +| ||:diagtext:`union` || | +| |+------------------+| | +| ||:diagtext:`vector`|| | +| |+------------------+| | ++-------------------------------------------------------------------------------------------------------------------+--------------------+------------------------+ + + -Wodr ----- This diagnostic is enabled by default. @@ -7188,6 +7500,10 @@ This diagnostic is enabled by default. **Diagnostic text:** ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`The OpenMP offloading target '`:placeholder:`A`:diagtext:`' is similar to target '`:placeholder:`B`:diagtext:`' already specified - will be ignored.`| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + +-----------------------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`declaration is not declared in any declare target region`| +-----------------------------------------------------------------------------------------------+ @@ -7468,6 +7784,10 @@ Also controls `-Wc++11-extra-semi`_, `-Wc++11-long-long`_, `-Wc++14-binary-liter |:warning:`warning:` |nbsp| :diagtext:`'enable\_if' is a clang extension`| +------------------------------------------------------------------------+ ++--------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`'diagnose\_if' is a clang extension`| ++--------------------------------------------------------------------------+ + +--------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`designated initializers are a C99 feature`| +--------------------------------------------------------------------------------+ @@ -8040,6 +8360,17 @@ This diagnostic is an error by default, but the flag ``-Wno-private-header`` can +----------------------------------------------------------------------------------------------------------------+ +-Wprivate-module +---------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++--------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`top-level module '`:placeholder:`A`:diagtext:`' in private module map, expected a submodule of '`:placeholder:`B`:diagtext:`'`| ++--------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + + -Wprofile-instr-out-of-date --------------------------- This diagnostic is enabled by default. @@ -8364,6 +8695,10 @@ Also controls `-Wreturn-type-c-linkage`_. | |+--------------------+| | +---------------------------------------------------+----------------------+-----------------------------------------------------------------+ ++--------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`control reaches end of non-void coroutine`| ++--------------------------------------------------------------------------------+ + +-------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`control reaches end of non-void function`| +-------------------------------------------------------------------------------+ @@ -8372,6 +8707,10 @@ Also controls `-Wreturn-type-c-linkage`_. |:warning:`warning:` |nbsp| :diagtext:`control reaches end of non-void lambda`| +-----------------------------------------------------------------------------+ ++----------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`control may reach end of non-void coroutine`| ++----------------------------------------------------------------------------------+ + +---------------------------------------------------------------------------------+ |:warning:`warning:` |nbsp| :diagtext:`control may reach end of non-void function`| +---------------------------------------------------------------------------------+ @@ -8586,6 +8925,14 @@ Also controls `-Wshadow-field-in-constructor-modified`_, `-Wshadow-ivar`_. | |||:diagtext:`field of` |nbsp| :placeholder:`C`| || | ||+--------------------------------------------+ || | |+-----------------------------------------------------------+| +| ||+----------------------------------------------+ || +| |||:diagtext:`typedef in` |nbsp| :placeholder:`C`| || +| ||+----------------------------------------------+ || +| |+-----------------------------------------------------------+| +| ||+-------------------------------------------------+ || +| |||:diagtext:`type alias in` |nbsp| :placeholder:`C`| || +| ||+-------------------------------------------------+ || +| |+-----------------------------------------------------------+| +--------------------------------------------------------------------+-------------------------------------------------------------+ @@ -8593,7 +8940,16 @@ Also controls `-Wshadow-field-in-constructor-modified`_, `-Wshadow-ivar`_. ------------ Some of the diagnostics controlled by this flag are enabled by default. -Controls `-Wshadow`_, `-Wshadow-field-in-constructor`_. +Controls `-Wshadow`_, `-Wshadow-field`_, `-Wshadow-field-in-constructor`_, `-Wshadow-uncaptured-local`_. + + +-Wshadow-field +-------------- +**Diagnostic text:** + ++------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`non-static data member '`:placeholder:`A`:diagtext:`' of '`:placeholder:`B`:diagtext:`' shadows member inherited from type '`:placeholder:`C`:diagtext:`'`| ++------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ -Wshadow-field-in-constructor @@ -8627,6 +8983,37 @@ This diagnostic is enabled by default. +------------------------------------------------------------------------------------------------------------------------------+ +-Wshadow-uncaptured-local +------------------------- +**Diagnostic text:** + ++--------------------------------------------------------------------+-------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`declaration shadows a` |nbsp| |+-----------------------------------------------------------+| +| ||:diagtext:`local variable` || +| |+-----------------------------------------------------------+| +| ||+-----------------------------------------------+ || +| |||:diagtext:`variable in` |nbsp| :placeholder:`C`| || +| ||+-----------------------------------------------+ || +| |+-----------------------------------------------------------+| +| ||+---------------------------------------------------------+|| +| |||:diagtext:`static data member of` |nbsp| :placeholder:`C`||| +| ||+---------------------------------------------------------+|| +| |+-----------------------------------------------------------+| +| ||+--------------------------------------------+ || +| |||:diagtext:`field of` |nbsp| :placeholder:`C`| || +| ||+--------------------------------------------+ || +| |+-----------------------------------------------------------+| +| ||+----------------------------------------------+ || +| |||:diagtext:`typedef in` |nbsp| :placeholder:`C`| || +| ||+----------------------------------------------+ || +| |+-----------------------------------------------------------+| +| ||+-------------------------------------------------+ || +| |||:diagtext:`type alias in` |nbsp| :placeholder:`C`| || +| ||+-------------------------------------------------+ || +| |+-----------------------------------------------------------+| ++--------------------------------------------------------------------+-------------------------------------------------------------+ + + -Wshift-count-negative ---------------------- This diagnostic is enabled by default. @@ -8726,6 +9113,15 @@ This diagnostic is enabled by default. ------------ This diagnostic flag exists for GCC compatibility, and has no effect in Clang. +-Wsigned-enum-bitfield +---------------------- +**Diagnostic text:** + ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`enums in the Microsoft ABI are signed integers by default; consider giving the enum` |nbsp| :placeholder:`A` |nbsp| :diagtext:`an unsigned underlying type to make this code portable`| ++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + + -Wsizeof-array-argument ----------------------- This diagnostic is enabled by default. @@ -8767,6 +9163,17 @@ This diagnostic is enabled by default. +-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------+ +-Wslash-u-filename +------------------ +This diagnostic is enabled by default. + +**Diagnostic text:** + ++--------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`'/U`:placeholder:`A`:diagtext:`' treated as the '/U' option`| ++--------------------------------------------------------------------------------------------------+ + + -Wsometimes-uninitialized ------------------------- **Diagnostic text:** @@ -8957,7 +9364,29 @@ This diagnostic flag exists for GCC compatibility, and has no effect in Clang. -Wstrict-prototypes ------------------- -This diagnostic flag exists for GCC compatibility, and has no effect in Clang. +**Diagnostic text:** + ++---------------------------------------------------+--------------------------------------------------------------+-------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`this` |nbsp| |+------------------------------------------------------------+| |nbsp| :diagtext:`a prototype`| +| ||:diagtext:`function declaration is not` || | +| |+------------------------------------------------------------+| | +| ||:diagtext:`old-style function definition is not preceded by`|| | +| |+------------------------------------------------------------+| | ++---------------------------------------------------+--------------------------------------------------------------+-------------------------------+ + + +-Wstrict-prototypes +------------------- +**Diagnostic text:** + ++---------------------------------------------------+--------------------------------------------------------------+-------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`this` |nbsp| |+------------------------------------------------------------+| |nbsp| :diagtext:`a prototype`| +| ||:diagtext:`function declaration is not` || | +| |+------------------------------------------------------------+| | +| ||:diagtext:`old-style function definition is not preceded by`|| | +| |+------------------------------------------------------------+| | ++---------------------------------------------------+--------------------------------------------------------------+-------------------------------+ + -Wstrict-selector-match ----------------------- @@ -9587,6 +10016,17 @@ This diagnostic is enabled by default. +-------------------------------------------------------------------------------------------------------------------------------------+ +-Wunable-to-open-stats-file +--------------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + ++-------------------------------------------------------------------------------------------------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`unable to open statistics output file '`:placeholder:`A`:diagtext:`': '`:placeholder:`B`:diagtext:`'`| ++-------------------------------------------------------------------------------------------------------------------------------------------+ + + -Wunavailable-declarations -------------------------- This diagnostic is enabled by default. @@ -10113,11 +10553,26 @@ This diagnostic is enabled by default. +------------------------------------------------------------------------------------------------------+ +-Wunusable-partial-specialization +--------------------------------- +This diagnostic is an error by default, but the flag ``-Wno-unusable-partial-specialization`` can be used to disable the error. + +**Diagnostic text:** + ++-----------------------+----------------------+--------------------------------------------------------------------+----------------------------------+------------------------------------------------------------------------------------------+ +|:error:`error:` |nbsp| |+--------------------+| |nbsp| :diagtext:`template partial specialization contains` |nbsp| |+--------------------------------+| |nbsp| :diagtext:`that cannot be deduced; this partial specialization will never be used`| +| ||:diagtext:`class` || ||:diagtext:`a template parameter`|| | +| |+--------------------+| |+--------------------------------+| | +| ||:diagtext:`variable`|| ||:diagtext:`template parameters` || | +| |+--------------------+| |+--------------------------------+| | ++-----------------------+----------------------+--------------------------------------------------------------------+----------------------------------+------------------------------------------------------------------------------------------+ + + -Wunused -------- Some of the diagnostics controlled by this flag are enabled by default. -Controls `-Wunused-argument`_, `-Wunused-function`_, `-Wunused-label`_, `-Wunused-local-typedef`_, `-Wunused-private-field`_, `-Wunused-property-ivar`_, `-Wunused-value`_, `-Wunused-variable`_. +Controls `-Wunused-argument`_, `-Wunused-function`_, `-Wunused-label`_, `-Wunused-lambda-capture`_, `-Wunused-local-typedef`_, `-Wunused-private-field`_, `-Wunused-property-ivar`_, `-Wunused-value`_, `-Wunused-variable`_. -Wunused-argument @@ -10237,6 +10692,19 @@ This diagnostic is enabled by default. +---------------------------------------------------------------------------+ +-Wunused-lambda-capture +----------------------- +**Diagnostic text:** + ++---------------------------------------------------------------------------------------------------------------+--------------------------------------------------+ +|:warning:`warning:` |nbsp| :diagtext:`lambda capture` |nbsp| :placeholder:`A` |nbsp| :diagtext:`is not` |nbsp| |+------------------------------------------------+| +| ||:diagtext:`used` || +| |+------------------------------------------------+| +| ||:diagtext:`required to be captured for this use`|| +| |+------------------------------------------------+| ++---------------------------------------------------------------------------------------------------------------+--------------------------------------------------+ + + -Wunused-local-typedef ---------------------- **Diagnostic text:** @@ -10384,6 +10852,15 @@ This diagnostic is enabled by default. +--------------------------------------------------------------------------------------------------------+----------------------------------------------------+ +-Wuser-defined-warnings +----------------------- +This diagnostic is enabled by default. + +**Diagnostic text:** + +The text of this diagnostic is not controlled by Clang. + + -Wvarargs --------- This diagnostic is enabled by default. @@ -10422,6 +10899,17 @@ This diagnostic is enabled by default. +------------------------------------------------------------------------+ +-Wvec-elem-size +--------------- +This diagnostic is an error by default, but the flag ``-Wno-vec-elem-size`` can be used to disable the error. + +**Diagnostic text:** + ++--------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +|:error:`error:` |nbsp| :diagtext:`vector operands do not have the same elements sizes (`:placeholder:`A` |nbsp| :diagtext:`and` |nbsp| :placeholder:`B`:diagtext:`)`| ++--------------------------------------------------------------------------------------------------------------------------------------------------------------------+ + + -Wvector-conversion ------------------- **Diagnostic text:** diff --git a/docs/ExternalClangExamples.rst b/docs/ExternalClangExamples.rst index e6076a5be6d1..b92fa3fcc068 100644 --- a/docs/ExternalClangExamples.rst +++ b/docs/ExternalClangExamples.rst @@ -85,3 +85,16 @@ List of projects and tools errors, fixit hints). See also `<http://l.rw.rw/clang_plugin>`_ for step-by-step instructions." +`<https://phabricator.kde.org/source/clazy>`_ + "clazy is a compiler plugin which allows clang to understand Qt semantics. + You get more than 50 Qt related compiler warnings, ranging from unneeded + memory allocations to misusage of API, including fix-its for automatic + refactoring." + +`<https://gerrit.libreoffice.org/gitweb?p=core.git;a=blob_plain;f=compilerplugins/README;hb=HEAD>`_ + "LibreOffice uses a Clang plugin infrastructure to check during the build + various things, some more, some less specific to the LibreOffice source code. + There are currently around 50 such checkers, from flagging C-style casts and + uses of reserved identifiers to ensuring that code adheres to lifecycle + protocols for certain LibreOffice-specific classes. They may serve as + examples for writing RecursiveASTVisitor-based plugins." diff --git a/docs/LTOVisibility.rst b/docs/LTOVisibility.rst index 67367f3d635e..e1372d667a1a 100644 --- a/docs/LTOVisibility.rst +++ b/docs/LTOVisibility.rst @@ -10,15 +10,16 @@ using link-time optimization; in the case where LTO is not being used, the linkage unit's LTO unit is empty. Each linkage unit has only a single LTO unit. The LTO visibility of a class is used by the compiler to determine which -classes the virtual function call optimization and control flow integrity -features apply to. These features use whole-program information, so they -require the entire class hierarchy to be visible in order to work correctly. - -If any translation unit in the program uses either of the virtual function -call optimization or control flow integrity features, it is effectively an -ODR violation to define a class with hidden LTO visibility in multiple linkage +classes the whole-program devirtualization (``-fwhole-program-vtables``) and +control flow integrity (``-fsanitize=cfi-vcall``) features apply to. These +features use whole-program information, so they require the entire class +hierarchy to be visible in order to work correctly. + +If any translation unit in the program uses either of the whole-program +devirtualization or control flow integrity features, it is effectively an ODR +violation to define a class with hidden LTO visibility in multiple linkage units. A class with public LTO visibility may be defined in multiple linkage -units, but the tradeoff is that the virtual function call optimization and +units, but the tradeoff is that the whole-program devirtualization and control flow integrity features can only be applied to classes with hidden LTO visibility. A class's LTO visibility is treated as an ODR-relevant property of its definition, so it must be consistent between translation units. diff --git a/docs/LanguageExtensions.rst b/docs/LanguageExtensions.rst index 885ad579ba72..a8fb4623b637 100644 --- a/docs/LanguageExtensions.rst +++ b/docs/LanguageExtensions.rst @@ -356,7 +356,7 @@ is: Query for this feature with ``__has_extension(attribute_ext_vector_type)``. -Giving ``-faltivec`` option to clang enables support for AltiVec vector syntax +Giving ``-maltivec`` option to clang enables support for AltiVec vector syntax and functions. For example: .. code-block:: c++ @@ -993,6 +993,7 @@ The following type trait primitives are supported by Clang: * ``__has_trivial_destructor`` (GNU, Microsoft) * ``__has_virtual_destructor`` (GNU, Microsoft) * ``__is_abstract`` (GNU, Microsoft) +* ``__is_aggregate`` (GNU, Microsoft) * ``__is_base_of`` (GNU, Microsoft) * ``__is_class`` (GNU, Microsoft) * ``__is_convertible_to`` (Microsoft) @@ -1780,7 +1781,7 @@ String builtins --------------- Clang provides constant expression evaluation support for builtins forms of -the following functions from the C standard library ``<strings.h>`` header: +the following functions from the C standard library ``<string.h>`` header: * ``memchr`` * ``memcmp`` @@ -2312,3 +2313,36 @@ For example, the hint ``vectorize_width(4)`` is ignored if the loop is not proven safe to vectorize. To identify and diagnose optimization issues use `-Rpass`, `-Rpass-missed`, and `-Rpass-analysis` command line options. See the user guide for details. + +Extensions to specify floating-point flags +==================================================== + +The ``#pragma clang fp`` pragma allows floating-point options to be specified +for a section of the source code. This pragma can only appear at file scope or +at the start of a compound statement (excluding comments). When using within a +compound statement, the pragma is active within the scope of the compound +statement. + +Currently, only FP contraction can be controlled with the pragma. ``#pragma +clang fp contract`` specifies whether the compiler should contract a multiply +and an addition (or subtraction) into a fused FMA operation when supported by +the target. + +The pragma can take three values: ``on``, ``fast`` and ``off``. The ``on`` +option is identical to using ``#pragma STDC FP_CONTRACT(ON)`` and it allows +fusion as specified the language standard. The ``fast`` option allows fusiong +in cases when the language standard does not make this possible (e.g. across +statements in C) + +.. code-block:: c++ + + for(...) { + #pragma clang fp contract(fast) + a = b[i] * c[i]; + d[i] += a; + } + + +The pragma can also be used with ``off`` which turns FP contraction off for a +section of the code. This can be useful when fast contraction is otherwise +enabled for the translation unit with the ``-ffp-contract=fast`` flag. diff --git a/docs/LibASTMatchersReference.html b/docs/LibASTMatchersReference.html index 4ee953f1838e..736e1dfcabcf 100644 --- a/docs/LibASTMatchersReference.html +++ b/docs/LibASTMatchersReference.html @@ -337,6 +337,15 @@ nonTypeTemplateParmDecl() </pre></td></tr> +<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('objcCategoryDecl0')"><a name="objcCategoryDecl0Anchor">objcCategoryDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCCategoryDecl.html">ObjCCategoryDecl</a>>...</td></tr> +<tr><td colspan="4" class="doc" id="objcCategoryDecl0"><pre>Matches Objective-C category declarations. + +Example matches Foo (Additions) + @interface Foo (Additions) + @end +</pre></td></tr> + + <tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('objcInterfaceDecl0')"><a name="objcInterfaceDecl0Anchor">objcInterfaceDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCInterfaceDecl.html">ObjCInterfaceDecl</a>>...</td></tr> <tr><td colspan="4" class="doc" id="objcInterfaceDecl0"><pre>Matches Objective-C interface declarations. @@ -346,6 +355,50 @@ Example matches Foo </pre></td></tr> +<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('objcIvarDecl0')"><a name="objcIvarDecl0Anchor">objcIvarDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCIvarDecl.html">ObjCIvarDecl</a>>...</td></tr> +<tr><td colspan="4" class="doc" id="objcIvarDecl0"><pre>Matches Objective-C instance variable declarations. + +Example matches _enabled + @implementation Foo { + BOOL _enabled; + } + @end +</pre></td></tr> + + +<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('objcMethodDecl0')"><a name="objcMethodDecl0Anchor">objcMethodDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCMethodDecl.html">ObjCMethodDecl</a>>...</td></tr> +<tr><td colspan="4" class="doc" id="objcMethodDecl0"><pre>Matches Objective-C method declarations. + +Example matches both declaration and definition of -[Foo method] + @interface Foo + - (void)method; + @end + + @implementation Foo + - (void)method {} + @end +</pre></td></tr> + + +<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('objcPropertyDecl0')"><a name="objcPropertyDecl0Anchor">objcPropertyDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCPropertyDecl.html">ObjCPropertyDecl</a>>...</td></tr> +<tr><td colspan="4" class="doc" id="objcPropertyDecl0"><pre>Matches Objective-C property declarations. + +Example matches enabled + @interface Foo + @property BOOL enabled; + @end +</pre></td></tr> + + +<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('objcProtocolDecl0')"><a name="objcProtocolDecl0Anchor">objcProtocolDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCProtocolDecl.html">ObjCProtocolDecl</a>>...</td></tr> +<tr><td colspan="4" class="doc" id="objcProtocolDecl0"><pre>Matches Objective-C protocol declarations. + +Example matches FooDelegate + @protocol FooDelegate + @end +</pre></td></tr> + + <tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('parmVarDecl0')"><a name="parmVarDecl0Anchor">parmVarDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1ParmVarDecl.html">ParmVarDecl</a>>...</td></tr> <tr><td colspan="4" class="doc" id="parmVarDecl0"><pre>Matches parameter variable declarations. @@ -416,6 +469,15 @@ typeAliasDecl() </pre></td></tr> +<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('typeAliasTemplateDecl0')"><a name="typeAliasTemplateDecl0Anchor">typeAliasTemplateDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1TypeAliasTemplateDecl.html">TypeAliasTemplateDecl</a>>...</td></tr> +<tr><td colspan="4" class="doc" id="typeAliasTemplateDecl0"><pre>Matches type alias template declarations. + +typeAliasTemplateDecl() matches + template <typename T> + using Y = X<T>; +</pre></td></tr> + + <tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>></td><td class="name" onclick="toggle('typedefDecl0')"><a name="typedefDecl0Anchor">typedefDecl</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1TypedefDecl.html">TypedefDecl</a>>...</td></tr> <tr><td colspan="4" class="doc" id="typedefDecl0"><pre>Matches typedef declarations. @@ -5419,7 +5481,7 @@ alignof. <tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>></td><td class="name" onclick="toggle('forFunction0')"><a name="forFunction0Anchor">forFunction</a></td><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>> InnerMatcher</td></tr> -<tr><td colspan="4" class="doc" id="forFunction0"><pre>Matches declaration of the function the statemenet belongs to +<tr><td colspan="4" class="doc" id="forFunction0"><pre>Matches declaration of the function the statement belongs to Given: F& operator=(const F& o) { diff --git a/docs/Modules.rst b/docs/Modules.rst index 141d3b85753f..2b1bde2fedc1 100644 --- a/docs/Modules.rst +++ b/docs/Modules.rst @@ -360,6 +360,7 @@ The ``framework`` qualifier specifies that this module corresponds to a Darwin-s Name.framework/ Modules/module.modulemap Module map for the framework Headers/ Subdirectory containing framework headers + PrivateHeaders/ Subdirectory containing framework private headers Frameworks/ Subdirectory containing embedded frameworks Resources/ Subdirectory containing additional resources Name Symbolic link to the shared library for the framework @@ -842,6 +843,16 @@ would be available when ``Foo_Private.h`` is available, making it easier to split a library's public and private APIs along header boundaries. +When writing a private module as part of a *framework*, it's recommended that: + +* Headers for this module are present in the ``PrivateHeaders`` + framework subdirectory. +* The private module is defined as a *submodule* of the public framework (if + there's one), similar to how ``Foo.Private`` is defined in the example above. +* The ``explicit`` keyword should be used to guarantee that its content will + only be available when the submodule itself is explicitly named (through a + ``@import`` for example). + Modularizing a Platform ======================= To get any benefit out of modules, one needs to introduce module maps for software libraries starting at the bottom of the stack. This typically means introducing a module map covering the operating system's headers and the C standard library headers (in ``/usr/include``, for a Unix system). diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst index 3278bcc03381..f7e31e5c98d5 100644 --- a/docs/ReleaseNotes.rst +++ b/docs/ReleaseNotes.rst @@ -1,6 +1,6 @@ -========================= -Clang 4.0.0 Release Notes -========================= +======================================= +Clang 5.0.0 (In-Progress) Release Notes +======================================= .. contents:: :local: @@ -8,11 +8,17 @@ Clang 4.0.0 Release Notes Written by the `LLVM Team <http://llvm.org/>`_ +.. warning:: + + These are in-progress notes for the upcoming Clang 5 release. + Release notes for previous releases can be found on + `the Download Page <http://releases.llvm.org/download.html>`_. + Introduction ============ -This document contains the release notes for the Clang C/C++/Objective-C/OpenCL -frontend, part of the LLVM Compiler Infrastructure, release 4.0.0. Here we +This document contains the release notes for the Clang C/C++/Objective-C +frontend, part of the LLVM Compiler Infrastructure, release 5.0.0. Here we describe the status of Clang in some detail, including major improvements from the previous release and new feature work. For the general LLVM release notes, see `the LLVM @@ -25,7 +31,12 @@ the latest release, please check out the main please see the `Clang Web Site <http://clang.llvm.org>`_ or the `LLVM Web Site <http://llvm.org>`_. -What's New in Clang 4.0.0? +Note that if you are reading this file from a Subversion checkout or the +main Clang web page, this document applies to the *next* release, not +the current one. To see the release notes for a specific release, please +see the `releases page <http://llvm.org/releases/>`_. + +What's New in Clang 5.0.0? ========================== Some of the major new features and improvements to Clang are listed @@ -36,147 +47,165 @@ sections with improvements to Clang's support for those languages. Major New Features ------------------ -- The `diagnose_if <AttributeReference.html#diagnose-if>`_ attribute has been - added to clang. This attribute allows - clang to emit a warning or error if a function call meets one or more - user-specified conditions. - -- Enhanced devirtualization with - `-fstrict-vtable-pointers <UsersManual.html#cmdoption-fstrict-vtable-pointers>`_. - Clang devirtualizes across different basic blocks, like loops: - - .. code-block:: c++ - - struct A { - virtual void foo(); - }; - void indirect(A &a, int n) { - for (int i = 0 ; i < n; i++) - a.foo(); - } - void test(int n) { - A a; - indirect(a, n); - } - - -Improvements to ThinLTO (-flto=thin) ------------------------------------- -- Integration with profile data (PGO). When available, profile data enables - more accurate function importing decisions, as well as cross-module indirect - call promotion. -- Significant build-time and binary-size improvements when compiling with debug - info (``-g``). +- ... + +Improvements to Clang's diagnostics +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +- -Wunused-lambda-capture warns when a variable explicitly captured + by a lambda is not used in the body of the lambda. New Compiler Flags ------------------ -- The option ``-Og`` has been added to optimize the debugging experience. - For now, this option is exactly the same as ``-O1``. However, in the future, - some other optimizations might be enabled or disabled. +The option .... + +New Pragmas in Clang +----------------------- + +Clang now supports the ... + + +Attribute Changes in Clang +-------------------------- + +- ... + +Windows Support +--------------- + +Clang's support for building native Windows programs ... + + +C Language Changes in Clang +--------------------------- + +- ... -- The option ``-MJ`` has been added to simplify adding JSON compilation - database output into existing build systems. +... +C11 Feature Support +^^^^^^^^^^^^^^^^^^^ + +... + +C++ Language Changes in Clang +----------------------------- + +... + +C++1z Feature Support +^^^^^^^^^^^^^^^^^^^^^ + +... + +Objective-C Language Changes in Clang +------------------------------------- + +... OpenCL C Language Changes in Clang ---------------------------------- -**The following bugs in the OpenCL header have been fixed:** +... + +OpenMP Support in Clang +---------------------------------- + +... -* Added missing ``overloadable`` and ``convergent`` attributes. -* Removed some erroneous extra ``native_*`` functions. +Internal API Changes +-------------------- -**The following bugs in the generation of metadata have been fixed:** +These are major API changes that have happened since the 4.0.0 release of +Clang. If upgrading an external codebase that uses Clang as a library, +this section should help get you past the largest hurdles of upgrading. -* Corrected the SPIR version depending on the OpenCL version. -* Source level address spaces are taken from the SPIR specification. -* Image types now contain no access qualifier. +- ... -**The following bugs in the AMD target have been fixed:** +AST Matchers +------------ -* Corrected the bitwidth of ``size_t`` and NULL pointer value with respect to - address spaces. -* Added ``cl_khr_subgroups``, ``cl_amd_media_ops`` and ``cl_amd_media_ops2`` - extensions. -* Added ``cl-denorms-are-zero`` support. -* Changed address spaces for image objects to be ``constant``. -* Added little-endian. +... -**The following bugs in OpenCL 2.0 have been fixed:** -* Fixed pipe builtin function return type, added extra argument to generated - IR intrinsics to propagate size and alignment information of the pipe packed - type. -* Improved pipe type to accommodate access qualifiers. -* Added correct address space to the ObjC block generation and ``enqueue_kernel`` - prototype. -* Improved handling of integer parameters of ``enqueue_kernel`` prototype. We - now allow ``size_t`` instead of ``int`` for specifying block parameter sizes. -* Allow using NULL (aka ``CLK_NULL_QUEUE``) with ``queue_t``. +clang-format +------------ +* Option **BreakBeforeInheritanceComma** added to break before ``:`` and ``,`` in case of + multiple inheritance in a class declaration. Enabled by default in the Mozilla coding style. -**Improved the following diagnostics:** + +---------------------+----------------------------------------+ + | true | false | + +=====================+========================================+ + | .. code-block:: c++ | .. code-block:: c++ | + | | | + | class MyClass | class MyClass : public X, public Y { | + | : public X | }; | + | , public Y { | | + | }; | | + +---------------------+----------------------------------------+ -* Disallow address spaces other than ``global`` for kernel pointer parameters. -* Correct the use of half type argument and pointer assignment with - dereferencing. -* Disallow variadic arguments in functions and blocks. -* Allow partial initializer for array and struct. +* Align block comment decorations. -**Some changes to OpenCL extensions have been made:** + +----------------------+---------------------+ + | Before | After | + +======================+=====================+ + | .. code-block:: c++ | .. code-block:: c++ | + | | | + | /* line 1 | /* line 1 | + | * line 2 | * line 2 | + | */ | */ | + +----------------------+---------------------+ -* Added ``cl_khr_mipmap_image``. -* Added ``-cl-ext`` flag to allow overwriting supported extensions otherwise - set by the target compiled for (Example: ``-cl-ext=-all,+cl_khr_fp16``). -* New types and functions can now be flexibly added to extensions using the - following pragmas instead of modifying the Clang source code: +* The :doc:`ClangFormatStyleOptions` documentation provides detailed examples for most options. - .. code-block:: c +* Namespace end comments are now added or updated automatically. - #pragma OPENCL EXTENSION the_new_extension_name : begin - // declare types and functions associated with the extension here - #pragma OPENCL EXTENSION the_new_extension_name : end + +---------------------+---------------------+ + | Before | After | + +=====================+=====================+ + | .. code-block:: c++ | .. code-block:: c++ | + | | | + | namespace A { | namespace A { | + | int i; | int i; | + | int j; | int j; | + | } | } | + +---------------------+---------------------+ +* Comment reflow support added. Overly long comment lines will now be reflown with the rest of + the paragraph instead of just broken. Option **ReflowComments** added and enabled by default. -**Miscellaneous changes:** +libclang +-------- -* Fix ``__builtin_astype`` to cast between different address space objects. -* Allow using ``opencl_unroll_hint`` with earlier OpenCL versions than 2.0. -* Improved handling of floating point literal to default to single precision if - fp64 extension is not enabled. -* Refactor ``sampler_t`` implementation to simplify initializer representation - which is now handled as a compiler builtin function with an integer value - passed into it. -* Change fake address space map to use the SPIR convention. -* Added `the OpenCL manual <UsersManual.html#opencl-features>`_ to Clang - documentation. +... Static Analyzer --------------- -With the option ``--show-description``, scan-build's list of defects will also -show the description of the defects. +... + +Core Analysis Improvements +========================== + +- ... + +New Issues Found +================ -The analyzer now provides better support of code that uses gtest. +- ... -Several new checks were added: +Python Binding Changes +---------------------- -- The analyzer warns when virtual calls are made from constructors or - destructors. This check is off by default but can be enabled by passing the - following command to scan-build: ``-enable-checker optin.cplusplus.VirtualCall``. -- The analyzer checks for synthesized copy properties of mutable types in - Objective C, such as ``NSMutableArray``. Calling the setter for these properties - will store an immutable copy of the value. -- The analyzer checks for calls to ``dispatch_once()`` that use an Objective-C - instance variable as the predicate. Using an instance variable as a predicate - may result in the passed-in block being executed multiple times or not at all. - These calls should be rewritten either to use a lock or to store the predicate - in a global or static variable. -- The analyzer checks for unintended comparisons of ``NSNumber``, ``CFNumberRef``, and - other Cocoa number objects to scalar values. +The following methods have been added: +- ... + +Significant Known Problems +========================== Additional Information ====================== diff --git a/docs/SanitizerCoverage.rst b/docs/SanitizerCoverage.rst index 3e8102a12f67..8ff5bdf3a3d2 100644 --- a/docs/SanitizerCoverage.rst +++ b/docs/SanitizerCoverage.rst @@ -227,7 +227,8 @@ easily used for bitset-based corpus distillation. Caller-callee coverage ====================== -(Experimental!) +**Deprecated, don't use** + Every indirect function call is instrumented with a run-time function call that captures caller and callee. At the shutdown time the process dumps a separate file called ``caller-callee.PID.sancov`` which contains caller/callee pairs as @@ -253,6 +254,8 @@ Current limitations: Coverage counters ================= +**Deprecated, don't use** + This experimental feature is inspired by `AFL <http://lcamtuf.coredump.cx/afl/technical_details.txt>`__'s coverage instrumentation. With additional compile-time and run-time flags you can get @@ -296,6 +299,9 @@ These counters may also be used for in-process coverage-guided fuzzers. See Tracing basic blocks ==================== + +**Deprecated, don't use** + Experimental support for basic block (or edge) tracing. With ``-fsanitize-coverage=trace-bb`` the compiler will insert ``__sanitizer_cov_trace_basic_block(s32 *id)`` before every function, basic block, or edge @@ -319,6 +325,9 @@ Basic block tracing is currently supported only for single-threaded applications Tracing PCs =========== + +**Deprecated, don't use** + *Experimental* feature similar to tracing basic blocks, but with a different API. With ``-fsanitize-coverage=trace-pc`` the compiler will insert ``__sanitizer_cov_trace_pc()`` on every edge. @@ -331,16 +340,13 @@ and can be used with `AFL <http://lcamtuf.coredump.cx/afl>`__. Tracing PCs with guards ======================= -Another *experimental* feature that tries to combine the functionality of `trace-pc`, -`8bit-counters` and boolean coverage. With ``-fsanitize-coverage=trace-pc-guard`` the compiler will insert the following code on every edge: .. code-block:: none - if (guard_variable) - __sanitizer_cov_trace_pc_guard(&guard_variable) + __sanitizer_cov_trace_pc_guard(&guard_variable) Every edge will have its own `guard_variable` (uint32_t). @@ -349,10 +355,11 @@ The compler will also insert a module constructor that will call .. code-block:: c++ // The guards are [start, stop). - // This function may be called multiple times with the same values of start/stop. + // This function will be called at least once per DSO and may be called + // more than once with the same values of start/stop. __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop); -Similarly to `trace-pc,indirect-calls`, with `trace-pc-guards,indirect-calls` +With `trace-pc-guards,indirect-calls` ``__sanitizer_cov_trace_pc_indirect(void *callee)`` will be inserted on every indirect call. The functions `__sanitizer_cov_trace_pc_*` should be defined by the user. @@ -367,10 +374,10 @@ Example: #include <sanitizer/coverage_interface.h> // This callback is inserted by the compiler as a module constructor - // into every compilation unit. 'start' and 'stop' correspond to the + // into every DSO. 'start' and 'stop' correspond to the // beginning and end of the section with the guards for the entire - // binary (executable or DSO) and so it will be called multiple times - // with the same parameters. + // binary (executable or DSO). The callback will be called at least + // once per DSO and may be called multiple times with the same parameters. extern "C" void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { static uint64_t N; // Counter for the guards. diff --git a/docs/SourceBasedCodeCoverage.rst b/docs/SourceBasedCodeCoverage.rst index abb682355b1c..474af30ae30f 100644 --- a/docs/SourceBasedCodeCoverage.rst +++ b/docs/SourceBasedCodeCoverage.rst @@ -18,6 +18,7 @@ Clang ships two other code coverage implementations: various sanitizers. It can provide up to edge-level coverage. * gcov - A GCC-compatible coverage implementation which operates on DebugInfo. + This is enabled by ``-ftest-coverage`` or ``--coverage``. From this point onwards "code coverage" will refer to the source-based kind. @@ -256,6 +257,8 @@ without using static initializers, do this manually: otherwise. Calling this function multiple times appends profile data to an existing on-disk raw profile. +In C++ files, declare these as ``extern "C"``. + Collecting coverage reports for the llvm project ================================================ diff --git a/docs/UndefinedBehaviorSanitizer.rst b/docs/UndefinedBehaviorSanitizer.rst index 09ee78f5876d..9bec5506359f 100644 --- a/docs/UndefinedBehaviorSanitizer.rst +++ b/docs/UndefinedBehaviorSanitizer.rst @@ -50,9 +50,9 @@ instead of ``clang++`` if you're compiling/linking C code. You can enable only a subset of :ref:`checks <ubsan-checks>` offered by UBSan, and define the desired behavior for each kind of check: -* print a verbose error report and continue execution (default); -* print a verbose error report and exit the program; -* execute a trap instruction (doesn't require UBSan run-time support). +* ``-fsanitize=...``: print a verbose error report and continue execution (default); +* ``-fno-sanitize-recover=...``: print a verbose error report and exit the program; +* ``-fsanitize-trap=...``: execute a trap instruction (doesn't require UBSan run-time support). For example if you compile/link your program as: @@ -92,6 +92,12 @@ Available checks are: parameter which is declared to never be null. - ``-fsanitize=null``: Use of a null pointer or creation of a null reference. + - ``-fsanitize=nullability-arg``: Passing null as a function parameter + which is annotated with ``_Nonnull``. + - ``-fsanitize=nullability-assign``: Assigning null to an lvalue which + is annotated with ``_Nonnull``. + - ``-fsanitize=nullability-return``: Returning null from a function with + a return type annotated with ``_Nonnull``. - ``-fsanitize=object-size``: An attempt to potentially use bytes which the optimizer can determine are not part of the object being accessed. This will also detect some types of undefined behavior that may not @@ -117,7 +123,9 @@ Available checks are: - ``-fsanitize=unreachable``: If control flow reaches ``__builtin_unreachable``. - ``-fsanitize=unsigned-integer-overflow``: Unsigned integer - overflows. + overflows. Note that unlike signed integer overflow, unsigned integer + is not undefined behavior. However, while it has well-defined semantics, + it is often unintentional, so UBSan offers to catch it. - ``-fsanitize=vla-bound``: A variable-length array whose bound does not evaluate to a positive value. - ``-fsanitize=vptr``: Use of an object whose vptr indicates that @@ -128,11 +136,15 @@ Available checks are: You can also use the following check groups: - ``-fsanitize=undefined``: All of the checks listed above other than - ``unsigned-integer-overflow``. + ``unsigned-integer-overflow`` and the ``nullability-*`` checks. - ``-fsanitize=undefined-trap``: Deprecated alias of ``-fsanitize=undefined``. - ``-fsanitize=integer``: Checks for undefined or suspicious integer behavior (e.g. unsigned integer overflow). + - ``-fsanitize=nullability``: Enables ``nullability-arg``, + ``nullability-assign``, and ``nullability-return``. While violating + nullability does not have undefined behavior, it is often unintentional, + so UBSan offers to catch it. Stack traces and report symbolization ===================================== @@ -145,6 +157,8 @@ will need to: ``UBSAN_OPTIONS=print_stacktrace=1``. #. Make sure ``llvm-symbolizer`` binary is in ``PATH``. +Stacktrace printing for UBSan issues is currently not supported on Darwin. + Issue Suppression ================= diff --git a/docs/UsersManual.rst b/docs/UsersManual.rst index 6c8355776b7b..7362456202ba 100644 --- a/docs/UsersManual.rst +++ b/docs/UsersManual.rst @@ -562,6 +562,16 @@ control the crash diagnostics. The -fno-crash-diagnostics flag can be helpful for speeding the process of generating a delta reduced test case. +Clang is also capable of generating preprocessed source file(s) and associated +run script(s) even without a crash. This is specially useful when trying to +generate a reproducer for warnings or errors while using modules. + +.. option:: -gen-reproducer + + Generates preprocessed source files, a reproducer script and if relevant, a + cache containing: built module pcm's and all headers needed to rebuilt the + same modules. + .. _rpass: Options to Emit Optimization Reports @@ -757,6 +767,7 @@ existed. #if foo #endif foo // warning: extra tokens at end of #endif directive + #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wextra-tokens" #if foo @@ -1695,6 +1706,22 @@ below. If multiple flags are present, the last one is used. Generate complete debug info. +Controlling Macro Debug Info Generation +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Debug info for C preprocessor macros increases the size of debug information in +the binary. Macro debug info generated by Clang can be controlled by the flags +listed below. + +.. option:: -fdebug-macro + + Generate debug info for preprocessor macros. This flag is discarded when + **-g0** is enabled. + +.. option:: -fno-debug-macro + + Do not generate debug info for preprocessor macros (default). + Controlling Debugger "Tuning" ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -1862,7 +1889,7 @@ missing from this list, please send an e-mail to cfe-dev. This list currently excludes C++; see :ref:`C++ Language Features <cxx>`. Also, this list does not include bugs in mostly-implemented features; please see the `bug -tracker <http://llvm.org/bugs/buglist.cgi?quicksearch=product%3Aclang+component%3A-New%2BBugs%2CAST%2CBasic%2CDriver%2CHeaders%2CLLVM%2BCodeGen%2Cparser%2Cpreprocessor%2CSemantic%2BAnalyzer>`_ +tracker <https://bugs.llvm.org/buglist.cgi?quicksearch=product%3Aclang+component%3A-New%2BBugs%2CAST%2CBasic%2CDriver%2CHeaders%2CLLVM%2BCodeGen%2Cparser%2Cpreprocessor%2CSemantic%2BAnalyzer>`_ for known existing bugs (FIXME: Is there a section for bug-reporting guidelines somewhere?). @@ -2273,7 +2300,7 @@ An example is the subgroup operations such as `intel_sub_group_shuffle // Define custom my_sub_group_shuffle(data, c) // that makes use of intel_sub_group_shuffle - r1 = … + r1 = ... if (r0) r1 = computeA(); // Shuffle data from r1 into r3 // of threads id r2. @@ -2284,7 +2311,7 @@ with non-SPMD semantics this is optimized to the following equivalent code: .. code-block:: c - r1 = … + r1 = ... if (!r0) // Incorrect functionality! The data in r1 // have not been computed by all threads yet. @@ -2499,7 +2526,7 @@ official `MinGW-w64 website <http://mingw-w64.sourceforge.net>`_. Clang expects the GCC executable "gcc.exe" compiled for ``i686-w64-mingw32`` (or ``x86_64-w64-mingw32``) to be present on PATH. -`Some tests might fail <http://llvm.org/bugs/show_bug.cgi?id=9072>`_ on +`Some tests might fail <https://bugs.llvm.org/show_bug.cgi?id=9072>`_ on ``x86_64-w64-mingw32``. .. _clang-cl: @@ -2542,7 +2569,7 @@ options are spelled with a leading ``/``, they will be mistaken for a filename: clang-cl.exe: error: no such file or directory: '/foobar' -Please `file a bug <http://llvm.org/bugs/enter_bug.cgi?product=clang&component=Driver>`_ +Please `file a bug <https://bugs.llvm.org/enter_bug.cgi?product=clang&component=Driver>`_ for any valid cl.exe flags that clang-cl does not understand. Execute ``clang-cl /?`` to see a list of supported options: diff --git a/docs/analyzer/DebugChecks.rst b/docs/analyzer/DebugChecks.rst index ecf11ca0f133..880dcfc9609c 100644 --- a/docs/analyzer/DebugChecks.rst +++ b/docs/analyzer/DebugChecks.rst @@ -178,15 +178,21 @@ ExprInspection checks This function explains the value of its argument in a human-readable manner in the warning message. You can make as many overrides of its prototype in the test code as necessary to explain various integral, pointer, - or even record-type values. + or even record-type values. To simplify usage in C code (where overloading + the function declaration is not allowed), you may append an arbitrary suffix + to the function name, without affecting functionality. Example usage:: void clang_analyzer_explain(int); void clang_analyzer_explain(void *); + // Useful in C code + void clang_analyzer_explain_int(int); + void foo(int param, void *ptr) { clang_analyzer_explain(param); // expected-warning{{argument 'param'}} + clang_analyzer_explain_int(param); // expected-warning{{argument 'param'}} if (!ptr) clang_analyzer_explain(ptr); // expected-warning{{memory address '0'}} } diff --git a/docs/analyzer/conf.py b/docs/analyzer/conf.py index 6b54b0646eca..c40af7a5e832 100644 --- a/docs/analyzer/conf.py +++ b/docs/analyzer/conf.py @@ -48,10 +48,10 @@ copyright = u'2013-%d, Analyzer Team' % date.today().year # |version| and |release|, also used in various other places throughout the # built documents. # -# The short X.Y version. -version = '4.0' +# The short version. +version = '5' # The full version, including alpha/beta/rc tags. -release = '4.0' +release = '5' # The language for content autogenerated by Sphinx. Refer to documentation # for a list of supported languages. diff --git a/docs/conf.py b/docs/conf.py index 9cf8d3772952..a9861cd5170a 100644 --- a/docs/conf.py +++ b/docs/conf.py @@ -48,10 +48,10 @@ copyright = u'2007-%d, The Clang Team' % date.today().year # |version| and |release|, also used in various other places throughout the # built documents. # -# The short X.Y version. -version = '4' +# The short version. +version = '5' # The full version, including alpha/beta/rc tags. -release = '4' +release = '5' # The language for content autogenerated by Sphinx. Refer to documentation # for a list of supported languages. diff --git a/docs/doxygen.cfg.in b/docs/doxygen.cfg.in index c96ab49ba0f9..ef96605ed1c1 100644 --- a/docs/doxygen.cfg.in +++ b/docs/doxygen.cfg.in @@ -1885,7 +1885,7 @@ ENABLE_PREPROCESSING = YES # The default value is: NO. # This tag requires that the tag ENABLE_PREPROCESSING is set to YES. -MACRO_EXPANSION = NO +MACRO_EXPANSION = YES # If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES then # the macro expansion is limited to the macros specified with the PREDEFINED and @@ -1893,7 +1893,7 @@ MACRO_EXPANSION = NO # The default value is: NO. # This tag requires that the tag ENABLE_PREPROCESSING is set to YES. -EXPAND_ONLY_PREDEF = NO +EXPAND_ONLY_PREDEF = YES # If the SEARCH_INCLUDES tag is set to YES the includes files in the # INCLUDE_PATH will be searched if a #include is found. @@ -1925,7 +1925,7 @@ INCLUDE_FILE_PATTERNS = # recursively expanded use the := operator instead of the = operator. # This tag requires that the tag ENABLE_PREPROCESSING is set to YES. -PREDEFINED = +PREDEFINED = LLVM_ALIGNAS(x)= # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this # tag can be used to specify a list of macro names that should be expanded. The diff --git a/docs/index.rst b/docs/index.rst index 61f9c2c49426..0097ebbf65f2 100644 --- a/docs/index.rst +++ b/docs/index.rst @@ -19,6 +19,7 @@ Using Clang as a Compiler UsersManual Toolchain LanguageExtensions + ClangCommandLineReference AttributeReference DiagnosticsReference CrossCompilation diff --git a/docs/tools/dump_format_style.py b/docs/tools/dump_format_style.py index 6e1493949815..81a5af6ef42b 100644 --- a/docs/tools/dump_format_style.py +++ b/docs/tools/dump_format_style.py @@ -19,7 +19,6 @@ def substitute(text, tag, contents): return re.sub(pattern, '%s', text, flags=re.S) % replacement def doxygen2rst(text): - text = re.sub(r'([^/\*])\*', r'\1\\*', text) text = re.sub(r'<tt>\s*(.*?)\s*<\/tt>', r'``\1``', text) text = re.sub(r'\\c ([^ ,;\.]+)', r'``\1``', text) text = re.sub(r'\\\w+ ', '', text) @@ -65,7 +64,7 @@ class NestedField: self.comment = comment.strip() def __str__(self): - return '* ``%s`` %s' % (self.name, doxygen2rst(self.comment)) + return '\n* ``%s`` %s' % (self.name, doxygen2rst(self.comment)) class Enum: def __init__(self, name, comment): |