diff options
Diffstat (limited to 'source/Plugins/ExpressionParser/Clang/IRForTarget.h')
| -rw-r--r-- | source/Plugins/ExpressionParser/Clang/IRForTarget.h | 1221 |
1 files changed, 619 insertions, 602 deletions
diff --git a/source/Plugins/ExpressionParser/Clang/IRForTarget.h b/source/Plugins/ExpressionParser/Clang/IRForTarget.h index 0f95f67babfd..20b1d1a13226 100644 --- a/source/Plugins/ExpressionParser/Clang/IRForTarget.h +++ b/source/Plugins/ExpressionParser/Clang/IRForTarget.h @@ -1,4 +1,5 @@ -//===-- IRForTarget.h ---------------------------------------------*- C++ -*-===// +//===-- IRForTarget.h ---------------------------------------------*- C++ +//-*-===// // // The LLVM Compiler Infrastructure // @@ -10,38 +11,38 @@ #ifndef liblldb_IRForTarget_h_ #define liblldb_IRForTarget_h_ -#include "lldb/lldb-public.h" #include "lldb/Core/ConstString.h" #include "lldb/Core/Error.h" #include "lldb/Core/Stream.h" #include "lldb/Core/StreamString.h" #include "lldb/Symbol/TaggedASTType.h" +#include "lldb/lldb-public.h" #include "llvm/Pass.h" -#include <map> #include <functional> +#include <map> namespace llvm { - class BasicBlock; - class CallInst; - class Constant; - class ConstantInt; - class Function; - class GlobalValue; - class GlobalVariable; - class Instruction; - class IntegerType; - class Module; - class StoreInst; - class DataLayout; - class Type; - class Value; +class BasicBlock; +class CallInst; +class Constant; +class ConstantInt; +class Function; +class GlobalValue; +class GlobalVariable; +class Instruction; +class IntegerType; +class Module; +class StoreInst; +class DataLayout; +class Type; +class Value; } namespace lldb_private { - class ClangExpressionDeclMap; - class IRExecutionUnit; - class IRMemoryMap; +class ClangExpressionDeclMap; +class IRExecutionUnit; +class IRMemoryMap; } //---------------------------------------------------------------------- @@ -58,594 +59,610 @@ namespace lldb_private { /// transformations are discussed in more detail next to their relevant /// functions. //---------------------------------------------------------------------- -class IRForTarget : public llvm::ModulePass -{ +class IRForTarget : public llvm::ModulePass { public: - enum class LookupResult { - Success, - Fail, - Ignore - }; - - //------------------------------------------------------------------ - /// Constructor - /// - /// @param[in] decl_map - /// The list of externally-referenced variables for the expression, - /// for use in looking up globals and allocating the argument - /// struct. See the documentation for ClangExpressionDeclMap. - /// - /// @param[in] resolve_vars - /// True if the external variable references (including persistent - /// variables) should be resolved. If not, only external functions - /// are resolved. - /// - /// @param[in] execution_policy - /// Determines whether an IR interpreter can be used to statically - /// evaluate the expression. - /// - /// @param[in] const_result - /// This variable is populated with the statically-computed result - /// of the function, if it has no side-effects and the result can - /// be computed statically. - /// - /// @param[in] execution_unit - /// The holder for raw data associated with the expression. - /// - /// @param[in] error_stream - /// If non-NULL, a stream on which errors can be printed. - /// - /// @param[in] func_name - /// The name of the function to prepare for execution in the target. - //------------------------------------------------------------------ - IRForTarget(lldb_private::ClangExpressionDeclMap *decl_map, - bool resolve_vars, - lldb_private::IRExecutionUnit &execution_unit, - lldb_private::Stream *error_stream, - const char* func_name = "$__lldb_expr"); - - //------------------------------------------------------------------ - /// Destructor - //------------------------------------------------------------------ - ~IRForTarget() override; - - //------------------------------------------------------------------ - /// Run this IR transformer on a single module - /// - /// Implementation of the llvm::ModulePass::runOnModule() function. - /// - /// @param[in] llvm_module - /// The module to run on. This module is searched for the function - /// $__lldb_expr, and that function is passed to the passes one by - /// one. - /// - /// @param[in] interpreter_error - /// An error. If the expression fails to be interpreted, this error - /// is set to a reason why. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - runOnModule(llvm::Module &llvm_module) override; - - //------------------------------------------------------------------ - /// Interface stub - /// - /// Implementation of the llvm::ModulePass::assignPassManager() - /// function. - //------------------------------------------------------------------ - void - assignPassManager(llvm::PMStack &pass_mgr_stack, - llvm::PassManagerType pass_mgr_type = llvm::PMT_ModulePassManager) override; - - //------------------------------------------------------------------ - /// Returns PMT_ModulePassManager - /// - /// Implementation of the llvm::ModulePass::getPotentialPassManagerType() - /// function. - //------------------------------------------------------------------ - llvm::PassManagerType - getPotentialPassManagerType() const override; + enum class LookupResult { Success, Fail, Ignore }; + + //------------------------------------------------------------------ + /// Constructor + /// + /// @param[in] decl_map + /// The list of externally-referenced variables for the expression, + /// for use in looking up globals and allocating the argument + /// struct. See the documentation for ClangExpressionDeclMap. + /// + /// @param[in] resolve_vars + /// True if the external variable references (including persistent + /// variables) should be resolved. If not, only external functions + /// are resolved. + /// + /// @param[in] execution_policy + /// Determines whether an IR interpreter can be used to statically + /// evaluate the expression. + /// + /// @param[in] const_result + /// This variable is populated with the statically-computed result + /// of the function, if it has no side-effects and the result can + /// be computed statically. + /// + /// @param[in] execution_unit + /// The holder for raw data associated with the expression. + /// + /// @param[in] error_stream + /// If non-NULL, a stream on which errors can be printed. + /// + /// @param[in] func_name + /// The name of the function to prepare for execution in the target. + //------------------------------------------------------------------ + IRForTarget(lldb_private::ClangExpressionDeclMap *decl_map, bool resolve_vars, + lldb_private::IRExecutionUnit &execution_unit, + lldb_private::Stream &error_stream, + const char *func_name = "$__lldb_expr"); + + //------------------------------------------------------------------ + /// Destructor + //------------------------------------------------------------------ + ~IRForTarget() override; + + //------------------------------------------------------------------ + /// Run this IR transformer on a single module + /// + /// Implementation of the llvm::ModulePass::runOnModule() function. + /// + /// @param[in] llvm_module + /// The module to run on. This module is searched for the function + /// $__lldb_expr, and that function is passed to the passes one by + /// one. + /// + /// @param[in] interpreter_error + /// An error. If the expression fails to be interpreted, this error + /// is set to a reason why. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool runOnModule(llvm::Module &llvm_module) override; + + //------------------------------------------------------------------ + /// Interface stub + /// + /// Implementation of the llvm::ModulePass::assignPassManager() + /// function. + //------------------------------------------------------------------ + void assignPassManager(llvm::PMStack &pass_mgr_stack, + llvm::PassManagerType pass_mgr_type = + llvm::PMT_ModulePassManager) override; + + //------------------------------------------------------------------ + /// Returns PMT_ModulePassManager + /// + /// Implementation of the llvm::ModulePass::getPotentialPassManagerType() + /// function. + //------------------------------------------------------------------ + llvm::PassManagerType getPotentialPassManagerType() const override; private: - //------------------------------------------------------------------ - /// Ensures that the current function's linkage is set to external. - /// Otherwise the JIT may not return an address for it. - /// - /// @param[in] llvm_function - /// The function whose linkage is to be fixed. - /// - /// @return - /// True on success; false otherwise. - //------------------------------------------------------------------ - bool - FixFunctionLinkage (llvm::Function &llvm_function); - - //------------------------------------------------------------------ - /// A module-level pass to replace all function pointers with their - /// integer equivalents. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] llvm_module - /// The module currently being processed. - /// - /// @param[in] llvm_function - /// The function currently being processed. - /// - /// @return - /// True on success; false otherwise. - //------------------------------------------------------------------ - bool - HasSideEffects (llvm::Function &llvm_function); - - //------------------------------------------------------------------ - /// A function-level pass to check whether the function has side - /// effects. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Get the address of a function, and a location to put the complete - /// Value of the function if one is available. - /// - /// @param[in] function - /// The function to find the location of. - /// - /// @param[out] ptr - /// The location of the function in the target. - /// - /// @param[out] name - /// The resolved name of the function (matters for intrinsics). - /// - /// @param[out] value_ptr - /// A variable to put the function's completed Value* in, or NULL - /// if the Value* shouldn't be stored anywhere. - /// - /// @return - /// The pointer. - //------------------------------------------------------------------ - LookupResult - GetFunctionAddress (llvm::Function *function, - uint64_t &ptr, - lldb_private::ConstString &name, - llvm::Constant **&value_ptr); - - //------------------------------------------------------------------ - /// A function-level pass to take the generated global value - /// $__lldb_expr_result and make it into a persistent variable. - /// Also see ASTResultSynthesizer. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Find the NamedDecl corresponding to a Value. This interface is - /// exposed for the IR interpreter. - /// - /// @param[in] module - /// The module containing metadata to search - /// - /// @param[in] global - /// The global entity to search for - /// - /// @return - /// The corresponding variable declaration - //------------------------------------------------------------------ + //------------------------------------------------------------------ + /// Ensures that the current function's linkage is set to external. + /// Otherwise the JIT may not return an address for it. + /// + /// @param[in] llvm_function + /// The function whose linkage is to be fixed. + /// + /// @return + /// True on success; false otherwise. + //------------------------------------------------------------------ + bool FixFunctionLinkage(llvm::Function &llvm_function); + + //------------------------------------------------------------------ + /// A module-level pass to replace all function pointers with their + /// integer equivalents. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] llvm_module + /// The module currently being processed. + /// + /// @param[in] llvm_function + /// The function currently being processed. + /// + /// @return + /// True on success; false otherwise. + //------------------------------------------------------------------ + bool HasSideEffects(llvm::Function &llvm_function); + + //------------------------------------------------------------------ + /// A function-level pass to check whether the function has side + /// effects. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Get the address of a function, and a location to put the complete + /// Value of the function if one is available. + /// + /// @param[in] function + /// The function to find the location of. + /// + /// @param[out] ptr + /// The location of the function in the target. + /// + /// @param[out] name + /// The resolved name of the function (matters for intrinsics). + /// + /// @param[out] value_ptr + /// A variable to put the function's completed Value* in, or NULL + /// if the Value* shouldn't be stored anywhere. + /// + /// @return + /// The pointer. + //------------------------------------------------------------------ + LookupResult GetFunctionAddress(llvm::Function *function, uint64_t &ptr, + lldb_private::ConstString &name, + llvm::Constant **&value_ptr); + + //------------------------------------------------------------------ + /// A function-level pass to take the generated global value + /// $__lldb_expr_result and make it into a persistent variable. + /// Also see ASTResultSynthesizer. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Find the NamedDecl corresponding to a Value. This interface is + /// exposed for the IR interpreter. + /// + /// @param[in] module + /// The module containing metadata to search + /// + /// @param[in] global + /// The global entity to search for + /// + /// @return + /// The corresponding variable declaration + //------------------------------------------------------------------ public: - static clang::NamedDecl * - DeclForGlobal (const llvm::GlobalValue *global_val, llvm::Module *module); + static clang::NamedDecl *DeclForGlobal(const llvm::GlobalValue *global_val, + llvm::Module *module); + private: - clang::NamedDecl * - DeclForGlobal (llvm::GlobalValue *global); - - //------------------------------------------------------------------ - /// Set the constant result variable m_const_result to the provided - /// constant, assuming it can be evaluated. The result variable - /// will be reset to NULL later if the expression has side effects. - /// - /// @param[in] initializer - /// The constant initializer for the variable. - /// - /// @param[in] name - /// The name of the result variable. - /// - /// @param[in] type - /// The Clang type of the result variable. - //------------------------------------------------------------------ - void - MaybeSetConstantResult (llvm::Constant *initializer, - const lldb_private::ConstString &name, - lldb_private::TypeFromParser type); - - //------------------------------------------------------------------ - /// If the IR represents a cast of a variable, set m_const_result - /// to the result of the cast. The result variable will be reset to - /// NULL latger if the expression has side effects. - /// - /// @param[in] type - /// The Clang type of the result variable. - //------------------------------------------------------------------ - void - MaybeSetCastResult (lldb_private::TypeFromParser type); - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] llvm_function - /// The function currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - CreateResultVariable (llvm::Function &llvm_function); - - //------------------------------------------------------------------ - /// A module-level pass to find Objective-C constant strings and - /// transform them to calls to CFStringCreateWithBytes. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Rewrite a single Objective-C constant string. - /// - /// @param[in] NSStr - /// The constant NSString to be transformed - /// - /// @param[in] CStr - /// The constant C string inside the NSString. This will be - /// passed as the bytes argument to CFStringCreateWithBytes. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - RewriteObjCConstString (llvm::GlobalVariable *NSStr, - llvm::GlobalVariable *CStr); - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - RewriteObjCConstStrings (); - - //------------------------------------------------------------------ - /// A basic block-level pass to find all Objective-C method calls and - /// rewrite them to use sel_registerName instead of statically allocated - /// selectors. The reason is that the selectors are created on the - /// assumption that the Objective-C runtime will scan the appropriate - /// section and prepare them. This doesn't happen when code is copied - /// into the target, though, and there's no easy way to induce the - /// runtime to scan them. So instead we get our selectors from - /// sel_registerName. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Replace a single selector reference - /// - /// @param[in] selector_load - /// The load of the statically-allocated selector. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - RewriteObjCSelector (llvm::Instruction* selector_load); - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] basic_block - /// The basic block currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - RewriteObjCSelectors (llvm::BasicBlock &basic_block); - - //------------------------------------------------------------------ - /// A basic block-level pass to find all newly-declared persistent - /// variables and register them with the ClangExprDeclMap. This - /// allows them to be materialized and dematerialized like normal - /// external variables. Before transformation, these persistent - /// variables look like normal locals, so they have an allocation. - /// This pass excises these allocations and makes references look - /// like external references where they will be resolved -- like all - /// other external references -- by ResolveExternals(). - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Handle a single allocation of a persistent variable - /// - /// @param[in] persistent_alloc - /// The allocation of the persistent variable. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - RewritePersistentAlloc (llvm::Instruction *persistent_alloc); - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] basic_block - /// The basic block currently being processed. - //------------------------------------------------------------------ - bool - RewritePersistentAllocs (llvm::BasicBlock &basic_block); - - //------------------------------------------------------------------ - /// A function-level pass to find all external variables and functions - /// used in the IR. Each found external variable is added to the - /// struct, and each external function is resolved in place, its call - /// replaced with a call to a function pointer whose value is the - /// address of the function in the target process. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Write an initializer to a memory array of assumed sufficient - /// size. - /// - /// @param[in] data - /// A pointer to the data to write to. - /// - /// @param[in] initializer - /// The initializer itself. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - MaterializeInitializer (uint8_t *data, llvm::Constant *initializer); - - //------------------------------------------------------------------ - /// Move an internal variable into the static allocation section. - /// - /// @param[in] global_variable - /// The variable. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - MaterializeInternalVariable (llvm::GlobalVariable *global_variable); - - //------------------------------------------------------------------ - /// Handle a single externally-defined variable - /// - /// @param[in] value - /// The variable. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - MaybeHandleVariable (llvm::Value *value); - - //------------------------------------------------------------------ - /// Handle a single externally-defined symbol - /// - /// @param[in] symbol - /// The symbol. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - HandleSymbol (llvm::Value *symbol); - - //------------------------------------------------------------------ - /// Handle a single externally-defined Objective-C class - /// - /// @param[in] classlist_reference - /// The reference, usually "01L_OBJC_CLASSLIST_REFERENCES_$_n" - /// where n (if present) is an index. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - HandleObjCClass(llvm::Value *classlist_reference); - - //------------------------------------------------------------------ - /// Handle all the arguments to a function call - /// - /// @param[in] C - /// The call instruction. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - MaybeHandleCallArguments (llvm::CallInst *call_inst); - - //------------------------------------------------------------------ - /// Resolve variable references in calls to external functions - /// - /// @param[in] basic_block - /// The basic block currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - ResolveCalls (llvm::BasicBlock &basic_block); - - //------------------------------------------------------------------ - /// Remove calls to __cxa_atexit, which should never be generated by - /// expressions. - /// - /// @param[in] call_inst - /// The call instruction. - /// - /// @return - /// True if the scan was successful; false if some operation - /// failed - //------------------------------------------------------------------ - bool - RemoveCXAAtExit (llvm::BasicBlock &basic_block); - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] basic_block - /// The function currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - ResolveExternals (llvm::Function &llvm_function); - - //------------------------------------------------------------------ - /// A basic block-level pass to excise guard variables from the code. - /// The result for the function is passed through Clang as a static - /// variable. Static variables normally have guard variables to - /// ensure that they are only initialized once. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// Rewrite a load to a guard variable to return constant 0. - /// - /// @param[in] guard_load - /// The load instruction to zero out. - //------------------------------------------------------------------ - void - TurnGuardLoadIntoZero(llvm::Instruction* guard_load); - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] basic_block - /// The basic block currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - RemoveGuards (llvm::BasicBlock &basic_block); - - //------------------------------------------------------------------ - /// A function-level pass to make all external variable references - /// point at the correct offsets from the void* passed into the - /// function. ClangExpressionDeclMap::DoStructLayout() must be called - /// beforehand, so that the offsets are valid. - //------------------------------------------------------------------ - - //------------------------------------------------------------------ - /// The top-level pass implementation - /// - /// @param[in] llvm_function - /// The function currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - ReplaceVariables(llvm::Function &llvm_function); - - /// Flags - bool m_resolve_vars; ///< True if external variable references and persistent variable references should be resolved - lldb_private::ConstString m_func_name; ///< The name of the function to translate - lldb_private::ConstString m_result_name; ///< The name of the result variable ($0, $1, ...) - lldb_private::TypeFromParser m_result_type; ///< The type of the result variable. - llvm::Module *m_module; ///< The module being processed, or NULL if that has not been determined yet. - std::unique_ptr<llvm::DataLayout> - m_target_data; ///< The target data for the module being processed, or NULL if there is no module. - lldb_private::ClangExpressionDeclMap *m_decl_map; ///< The DeclMap containing the Decls - llvm::Constant *m_CFStringCreateWithBytes; ///< The address of the function CFStringCreateWithBytes, cast to the - ///appropriate function pointer type - llvm::Constant *m_sel_registerName; ///< The address of the function sel_registerName, cast to the appropriate - ///function pointer type - llvm::IntegerType *m_intptr_ty; ///< The type of an integer large enough to hold a pointer. - lldb_private::Stream *m_error_stream; ///< If non-NULL, the stream on which errors should be printed - lldb_private::IRExecutionUnit &m_execution_unit; ///< The execution unit containing the IR being created. - - llvm::StoreInst *m_result_store; ///< If non-NULL, the store instruction that writes to the result variable. If - ///m_has_side_effects is true, this is NULL. - bool m_result_is_pointer; ///< True if the function's result in the AST is a pointer (see comments in - ///ASTResultSynthesizer::SynthesizeBodyResult) - - llvm::GlobalVariable *m_reloc_placeholder; ///< A placeholder that will be replaced by a pointer to the final - ///location of the static allocation. - - //------------------------------------------------------------------ - /// UnfoldConstant operates on a constant [Old] which has just been - /// replaced with a value [New]. We assume that new_value has - /// been properly placed early in the function, in front of the - /// first instruction in the entry basic block - /// [FirstEntryInstruction]. - /// - /// UnfoldConstant reads through the uses of Old and replaces Old - /// in those uses with New. Where those uses are constants, the - /// function generates new instructions to compute the result of the - /// new, non-constant expression and places them before - /// FirstEntryInstruction. These instructions replace the constant - /// uses, so UnfoldConstant calls itself recursively for those. - /// - /// @param[in] llvm_function - /// The function currently being processed. - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - - class FunctionValueCache { - public: - typedef std::function <llvm::Value *(llvm::Function *)> Maker; - - FunctionValueCache (Maker const &maker); - ~FunctionValueCache (); - llvm::Value *GetValue (llvm::Function *function); - private: - Maker const m_maker; - typedef std::map<llvm::Function *, llvm::Value *> FunctionValueMap; - FunctionValueMap m_values; - }; - - FunctionValueCache m_entry_instruction_finder; - - static bool - UnfoldConstant (llvm::Constant *old_constant, - FunctionValueCache &value_maker, - FunctionValueCache &entry_instruction_finder); - - //------------------------------------------------------------------ - /// Construct a reference to m_reloc_placeholder with a given type - /// and offset. This typically happens after inserting data into - /// m_data_allocator. - /// - /// @param[in] type - /// The type of the value being loaded. - /// - /// @param[in] offset - /// The offset of the value from the base of m_data_allocator. - /// - /// @return - /// The Constant for the reference, usually a ConstantExpr. - //------------------------------------------------------------------ - llvm::Constant * - BuildRelocation(llvm::Type *type, - uint64_t offset); - - //------------------------------------------------------------------ - /// Commit the allocation in m_data_allocator and use its final - /// location to replace m_reloc_placeholder. - /// - /// @param[in] module - /// The module that m_data_allocator resides in - /// - /// @return - /// True on success; false otherwise - //------------------------------------------------------------------ - bool - CompleteDataAllocation (); + clang::NamedDecl *DeclForGlobal(llvm::GlobalValue *global); + + //------------------------------------------------------------------ + /// Set the constant result variable m_const_result to the provided + /// constant, assuming it can be evaluated. The result variable + /// will be reset to NULL later if the expression has side effects. + /// + /// @param[in] initializer + /// The constant initializer for the variable. + /// + /// @param[in] name + /// The name of the result variable. + /// + /// @param[in] type + /// The Clang type of the result variable. + //------------------------------------------------------------------ + void MaybeSetConstantResult(llvm::Constant *initializer, + const lldb_private::ConstString &name, + lldb_private::TypeFromParser type); + + //------------------------------------------------------------------ + /// If the IR represents a cast of a variable, set m_const_result + /// to the result of the cast. The result variable will be reset to + /// NULL latger if the expression has side effects. + /// + /// @param[in] type + /// The Clang type of the result variable. + //------------------------------------------------------------------ + void MaybeSetCastResult(lldb_private::TypeFromParser type); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] llvm_function + /// The function currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool CreateResultVariable(llvm::Function &llvm_function); + + //------------------------------------------------------------------ + /// A module-level pass to find Objective-C constant strings and + /// transform them to calls to CFStringCreateWithBytes. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Rewrite a single Objective-C constant string. + /// + /// @param[in] NSStr + /// The constant NSString to be transformed + /// + /// @param[in] CStr + /// The constant C string inside the NSString. This will be + /// passed as the bytes argument to CFStringCreateWithBytes. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewriteObjCConstString(llvm::GlobalVariable *NSStr, + llvm::GlobalVariable *CStr); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewriteObjCConstStrings(); + + //------------------------------------------------------------------ + /// A basic block-level pass to find all Objective-C method calls and + /// rewrite them to use sel_registerName instead of statically allocated + /// selectors. The reason is that the selectors are created on the + /// assumption that the Objective-C runtime will scan the appropriate + /// section and prepare them. This doesn't happen when code is copied + /// into the target, though, and there's no easy way to induce the + /// runtime to scan them. So instead we get our selectors from + /// sel_registerName. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Replace a single selector reference + /// + /// @param[in] selector_load + /// The load of the statically-allocated selector. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewriteObjCSelector(llvm::Instruction *selector_load); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] basic_block + /// The basic block currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewriteObjCSelectors(llvm::BasicBlock &basic_block); + + //------------------------------------------------------------------ + /// A basic block-level pass to find all Objective-C class references that + /// use the old-style Objective-C runtime and rewrite them to use + /// class_getClass instead of statically allocated class references. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Replace a single old-style class reference + /// + /// @param[in] selector_load + /// The load of the statically-allocated selector. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewriteObjCClassReference(llvm::Instruction *class_load); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] basic_block + /// The basic block currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewriteObjCClassReferences(llvm::BasicBlock &basic_block); + + //------------------------------------------------------------------ + /// A basic block-level pass to find all newly-declared persistent + /// variables and register them with the ClangExprDeclMap. This + /// allows them to be materialized and dematerialized like normal + /// external variables. Before transformation, these persistent + /// variables look like normal locals, so they have an allocation. + /// This pass excises these allocations and makes references look + /// like external references where they will be resolved -- like all + /// other external references -- by ResolveExternals(). + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Handle a single allocation of a persistent variable + /// + /// @param[in] persistent_alloc + /// The allocation of the persistent variable. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RewritePersistentAlloc(llvm::Instruction *persistent_alloc); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] basic_block + /// The basic block currently being processed. + //------------------------------------------------------------------ + bool RewritePersistentAllocs(llvm::BasicBlock &basic_block); + + //------------------------------------------------------------------ + /// A function-level pass to find all external variables and functions + /// used in the IR. Each found external variable is added to the + /// struct, and each external function is resolved in place, its call + /// replaced with a call to a function pointer whose value is the + /// address of the function in the target process. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Write an initializer to a memory array of assumed sufficient + /// size. + /// + /// @param[in] data + /// A pointer to the data to write to. + /// + /// @param[in] initializer + /// The initializer itself. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool MaterializeInitializer(uint8_t *data, llvm::Constant *initializer); + + //------------------------------------------------------------------ + /// Move an internal variable into the static allocation section. + /// + /// @param[in] global_variable + /// The variable. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool MaterializeInternalVariable(llvm::GlobalVariable *global_variable); + + //------------------------------------------------------------------ + /// Handle a single externally-defined variable + /// + /// @param[in] value + /// The variable. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool MaybeHandleVariable(llvm::Value *value); + + //------------------------------------------------------------------ + /// Handle a single externally-defined symbol + /// + /// @param[in] symbol + /// The symbol. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool HandleSymbol(llvm::Value *symbol); + + //------------------------------------------------------------------ + /// Handle a single externally-defined Objective-C class + /// + /// @param[in] classlist_reference + /// The reference, usually "01L_OBJC_CLASSLIST_REFERENCES_$_n" + /// where n (if present) is an index. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool HandleObjCClass(llvm::Value *classlist_reference); + + //------------------------------------------------------------------ + /// Handle all the arguments to a function call + /// + /// @param[in] C + /// The call instruction. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool MaybeHandleCallArguments(llvm::CallInst *call_inst); + + //------------------------------------------------------------------ + /// Resolve variable references in calls to external functions + /// + /// @param[in] basic_block + /// The basic block currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool ResolveCalls(llvm::BasicBlock &basic_block); + + //------------------------------------------------------------------ + /// Remove calls to __cxa_atexit, which should never be generated by + /// expressions. + /// + /// @param[in] call_inst + /// The call instruction. + /// + /// @return + /// True if the scan was successful; false if some operation + /// failed + //------------------------------------------------------------------ + bool RemoveCXAAtExit(llvm::BasicBlock &basic_block); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] basic_block + /// The function currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool ResolveExternals(llvm::Function &llvm_function); + + //------------------------------------------------------------------ + /// A basic block-level pass to excise guard variables from the code. + /// The result for the function is passed through Clang as a static + /// variable. Static variables normally have guard variables to + /// ensure that they are only initialized once. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// Rewrite a load to a guard variable to return constant 0. + /// + /// @param[in] guard_load + /// The load instruction to zero out. + //------------------------------------------------------------------ + void TurnGuardLoadIntoZero(llvm::Instruction *guard_load); + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] basic_block + /// The basic block currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool RemoveGuards(llvm::BasicBlock &basic_block); + + //------------------------------------------------------------------ + /// A function-level pass to make all external variable references + /// point at the correct offsets from the void* passed into the + /// function. ClangExpressionDeclMap::DoStructLayout() must be called + /// beforehand, so that the offsets are valid. + //------------------------------------------------------------------ + + //------------------------------------------------------------------ + /// The top-level pass implementation + /// + /// @param[in] llvm_function + /// The function currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool ReplaceVariables(llvm::Function &llvm_function); + + /// Flags + bool m_resolve_vars; ///< True if external variable references and persistent + ///variable references should be resolved + lldb_private::ConstString + m_func_name; ///< The name of the function to translate + lldb_private::ConstString + m_result_name; ///< The name of the result variable ($0, $1, ...) + lldb_private::TypeFromParser + m_result_type; ///< The type of the result variable. + llvm::Module *m_module; ///< The module being processed, or NULL if that has + ///not been determined yet. + std::unique_ptr<llvm::DataLayout> m_target_data; ///< The target data for the + ///module being processed, or + ///NULL if there is no + ///module. + lldb_private::ClangExpressionDeclMap + *m_decl_map; ///< The DeclMap containing the Decls + llvm::Constant *m_CFStringCreateWithBytes; ///< The address of the function + ///CFStringCreateWithBytes, cast to + ///the + /// appropriate function pointer type + llvm::Constant *m_sel_registerName; ///< The address of the function + ///sel_registerName, cast to the + ///appropriate + /// function pointer type + llvm::Constant *m_objc_getClass; ///< The address of the function + ///objc_getClass, cast to the + ///appropriate + /// function pointer type + llvm::IntegerType + *m_intptr_ty; ///< The type of an integer large enough to hold a pointer. + lldb_private::Stream + &m_error_stream; ///< The stream on which errors should be printed + lldb_private::IRExecutionUnit & + m_execution_unit; ///< The execution unit containing the IR being created. + + llvm::StoreInst *m_result_store; ///< If non-NULL, the store instruction that + ///writes to the result variable. If + /// m_has_side_effects is true, this is NULL. + bool m_result_is_pointer; ///< True if the function's result in the AST is a + ///pointer (see comments in + /// ASTResultSynthesizer::SynthesizeBodyResult) + + llvm::GlobalVariable *m_reloc_placeholder; ///< A placeholder that will be + ///replaced by a pointer to the + ///final + /// location of the static allocation. + + //------------------------------------------------------------------ + /// UnfoldConstant operates on a constant [Old] which has just been + /// replaced with a value [New]. We assume that new_value has + /// been properly placed early in the function, in front of the + /// first instruction in the entry basic block + /// [FirstEntryInstruction]. + /// + /// UnfoldConstant reads through the uses of Old and replaces Old + /// in those uses with New. Where those uses are constants, the + /// function generates new instructions to compute the result of the + /// new, non-constant expression and places them before + /// FirstEntryInstruction. These instructions replace the constant + /// uses, so UnfoldConstant calls itself recursively for those. + /// + /// @param[in] llvm_function + /// The function currently being processed. + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + + class FunctionValueCache { + public: + typedef std::function<llvm::Value *(llvm::Function *)> Maker; + + FunctionValueCache(Maker const &maker); + ~FunctionValueCache(); + llvm::Value *GetValue(llvm::Function *function); + + private: + Maker const m_maker; + typedef std::map<llvm::Function *, llvm::Value *> FunctionValueMap; + FunctionValueMap m_values; + }; + + FunctionValueCache m_entry_instruction_finder; + + static bool UnfoldConstant(llvm::Constant *old_constant, + llvm::Function *llvm_function, + FunctionValueCache &value_maker, + FunctionValueCache &entry_instruction_finder, + lldb_private::Stream &error_stream); + + //------------------------------------------------------------------ + /// Construct a reference to m_reloc_placeholder with a given type + /// and offset. This typically happens after inserting data into + /// m_data_allocator. + /// + /// @param[in] type + /// The type of the value being loaded. + /// + /// @param[in] offset + /// The offset of the value from the base of m_data_allocator. + /// + /// @return + /// The Constant for the reference, usually a ConstantExpr. + //------------------------------------------------------------------ + llvm::Constant *BuildRelocation(llvm::Type *type, uint64_t offset); + //------------------------------------------------------------------ + /// Commit the allocation in m_data_allocator and use its final + /// location to replace m_reloc_placeholder. + /// + /// @param[in] module + /// The module that m_data_allocator resides in + /// + /// @return + /// True on success; false otherwise + //------------------------------------------------------------------ + bool CompleteDataAllocation(); }; #endif // liblldb_IRForTarget_h_ |