diff options
Diffstat (limited to 'contrib/gcc/cp/cvt.c')
| -rw-r--r-- | contrib/gcc/cp/cvt.c | 1820 |
1 files changed, 1820 insertions, 0 deletions
diff --git a/contrib/gcc/cp/cvt.c b/contrib/gcc/cp/cvt.c new file mode 100644 index 000000000000..56508c1cd30f --- /dev/null +++ b/contrib/gcc/cp/cvt.c @@ -0,0 +1,1820 @@ +/* Language-level data type conversion for GNU C++. + Copyright (C) 1987, 88, 92, 93, 94, 1995 Free Software Foundation, Inc. + Hacked by Michael Tiemann (tiemann@cygnus.com) + +This file is part of GNU CC. + +GNU CC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU CC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU CC; see the file COPYING. If not, write to +the Free Software Foundation, 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. */ + + +/* This file contains the functions for converting C expressions + to different data types. The only entry point is `convert'. + Every language front end must have a `convert' function + but what kind of conversions it does will depend on the language. */ + +#include "config.h" +#include "tree.h" +#include "flags.h" +#include "cp-tree.h" +#include "class.h" +#include "convert.h" + +#undef NULL +#define NULL (char *)0 + +/* Change of width--truncation and extension of integers or reals-- + is represented with NOP_EXPR. Proper functioning of many things + assumes that no other conversions can be NOP_EXPRs. + + Conversion between integer and pointer is represented with CONVERT_EXPR. + Converting integer to real uses FLOAT_EXPR + and real to integer uses FIX_TRUNC_EXPR. + + Here is a list of all the functions that assume that widening and + narrowing is always done with a NOP_EXPR: + In convert.c, convert_to_integer. + In c-typeck.c, build_binary_op_nodefault (boolean ops), + and truthvalue_conversion. + In expr.c: expand_expr, for operands of a MULT_EXPR. + In fold-const.c: fold. + In tree.c: get_narrower and get_unwidened. + + C++: in multiple-inheritance, converting between pointers may involve + adjusting them by a delta stored within the class definition. */ + +/* Subroutines of `convert'. */ + +/* Build a thunk. What it is, is an entry point that when called will + adjust the this pointer (the first argument) by offset, and then + goto the real address of the function given by REAL_ADDR that we + would like called. What we return is the address of the thunk. */ +static tree +build_thunk (offset, real_addr) + tree offset, real_addr; +{ + if (TREE_CODE (real_addr) != ADDR_EXPR + || TREE_CODE (TREE_OPERAND (real_addr, 0)) != FUNCTION_DECL) + { + sorry ("MI pointer to member conversion too complex"); + return error_mark_node; + } + sorry ("MI pointer to member conversion too complex"); + return error_mark_node; +} + +/* Convert a `pointer to member' (POINTER_TYPE to METHOD_TYPE) into + another `pointer to method'. This may involved the creation of + a thunk to handle the this offset calculation. */ +static tree +convert_fn_ptr (type, expr) + tree type, expr; +{ + if (flag_vtable_thunks) + { + tree intype = TREE_TYPE (expr); + tree binfo = get_binfo (TYPE_METHOD_BASETYPE (TREE_TYPE (intype)), + TYPE_METHOD_BASETYPE (TREE_TYPE (type)), 1); + if (binfo == error_mark_node) + { + error (" in pointer to member conversion"); + return error_mark_node; + } + if (binfo == NULL_TREE) + { + /* ARM 4.8 restriction. */ + error ("invalid pointer to member conversion"); + return error_mark_node; + } + + if (BINFO_OFFSET_ZEROP (binfo)) + return build1 (NOP_EXPR, type, expr); + return build1 (NOP_EXPR, type, build_thunk (BINFO_OFFSET (binfo), expr)); + } + else + return build_ptrmemfunc (type, expr, 1); +} + +/* if converting pointer to pointer + if dealing with classes, check for derived->base or vice versa + else if dealing with method pointers, delegate + else convert blindly + else if converting class, pass off to build_type_conversion + else try C-style pointer conversion */ +static tree +cp_convert_to_pointer (type, expr) + tree type, expr; +{ + register tree intype = TREE_TYPE (expr); + register enum tree_code form; + + if (TYPE_PTRMEMFUNC_P (type)) + type = TYPE_PTRMEMFUNC_FN_TYPE (type); + if (TYPE_PTRMEMFUNC_P (intype)) + intype = TYPE_PTRMEMFUNC_FN_TYPE (intype); + + form = TREE_CODE (intype); + + if (form == POINTER_TYPE || form == REFERENCE_TYPE) + { + intype = TYPE_MAIN_VARIANT (intype); + + if (TYPE_MAIN_VARIANT (type) != intype + && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE + && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) + { + enum tree_code code = PLUS_EXPR; + tree binfo = get_binfo (TREE_TYPE (type), TREE_TYPE (intype), 1); + if (binfo == error_mark_node) + return error_mark_node; + if (binfo == NULL_TREE) + { + binfo = get_binfo (TREE_TYPE (intype), TREE_TYPE (type), 1); + if (binfo == error_mark_node) + return error_mark_node; + code = MINUS_EXPR; + } + if (binfo) + { + if (TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (type)) + || TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (intype)) + || ! BINFO_OFFSET_ZEROP (binfo)) + { + /* Need to get the path we took. */ + tree path; + + if (code == PLUS_EXPR) + get_base_distance (TREE_TYPE (type), TREE_TYPE (intype), 0, &path); + else + get_base_distance (TREE_TYPE (intype), TREE_TYPE (type), 0, &path); + return build_vbase_path (code, type, expr, path, 0); + } + } + } + if (TREE_CODE (TREE_TYPE (intype)) == METHOD_TYPE + && TREE_CODE (type) == POINTER_TYPE + && TREE_CODE (TREE_TYPE (type)) == METHOD_TYPE) + return convert_fn_ptr (type, expr); + + if (TREE_CODE (TREE_TYPE (type)) == OFFSET_TYPE + && TREE_CODE (TREE_TYPE (intype)) == OFFSET_TYPE) + { + tree b1 = TYPE_OFFSET_BASETYPE (TREE_TYPE (type)); + tree b2 = TYPE_OFFSET_BASETYPE (TREE_TYPE (intype)); + tree binfo = get_binfo (b1, b2, 1); + if (binfo == NULL_TREE) + binfo = get_binfo (b2, b1, 1); + if (binfo == error_mark_node) + return error_mark_node; + } + + if (TREE_CODE (TREE_TYPE (intype)) == METHOD_TYPE + || (TREE_CODE (type) == POINTER_TYPE + && TREE_CODE (TREE_TYPE (type)) == METHOD_TYPE)) + { + cp_error ("cannot convert `%E' from type `%T' to type `%T'", + expr, intype, type); + return error_mark_node; + } + + return build1 (NOP_EXPR, type, expr); + } + + my_friendly_assert (form != OFFSET_TYPE, 186); + + if (TYPE_LANG_SPECIFIC (intype) + && (IS_SIGNATURE_POINTER (intype) || IS_SIGNATURE_REFERENCE (intype))) + return convert_to_pointer (type, build_optr_ref (expr)); + + if (IS_AGGR_TYPE (intype)) + { + tree rval; + rval = build_type_conversion (CONVERT_EXPR, type, expr, 1); + if (rval) + { + if (rval == error_mark_node) + cp_error ("conversion of `%E' from `%T' to `%T' is ambiguous", + expr, intype, type); + return rval; + } + } + + if (integer_zerop (expr)) + { + if (type == TREE_TYPE (null_pointer_node)) + return null_pointer_node; + expr = build_int_2 (0, 0); + TREE_TYPE (expr) = type; + return expr; + } + + if (INTEGRAL_CODE_P (form)) + { + if (type_precision (intype) == POINTER_SIZE) + return build1 (CONVERT_EXPR, type, expr); + expr = convert (type_for_size (POINTER_SIZE, 0), expr); + /* Modes may be different but sizes should be the same. */ + if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) + != GET_MODE_SIZE (TYPE_MODE (type))) + /* There is supposed to be some integral type + that is the same width as a pointer. */ + abort (); + return convert_to_pointer (type, expr); + } + + cp_error ("cannot convert `%E' from type `%T' to type `%T'", + expr, intype, type); + return error_mark_node; +} + +/* Like convert, except permit conversions to take place which + are not normally allowed due to access restrictions + (such as conversion from sub-type to private super-type). */ +static tree +convert_to_pointer_force (type, expr) + tree type, expr; +{ + register tree intype = TREE_TYPE (expr); + register enum tree_code form = TREE_CODE (intype); + + if (integer_zerop (expr)) + { + if (type == TREE_TYPE (null_pointer_node)) + return null_pointer_node; + expr = build_int_2 (0, 0); + TREE_TYPE (expr) = type; + return expr; + } + + /* Convert signature pointer/reference to `void *' first. */ + if (form == RECORD_TYPE + && (IS_SIGNATURE_POINTER (intype) || IS_SIGNATURE_REFERENCE (intype))) + { + expr = build_optr_ref (expr); + intype = TREE_TYPE (expr); + form = TREE_CODE (intype); + } + + if (form == POINTER_TYPE) + { + intype = TYPE_MAIN_VARIANT (intype); + + if (TYPE_MAIN_VARIANT (type) != intype + && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE + && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) + { + enum tree_code code = PLUS_EXPR; + tree path; + int distance = get_base_distance (TREE_TYPE (type), + TREE_TYPE (intype), 0, &path); + if (distance == -2) + { + ambig: + cp_error ("type `%T' is ambiguous baseclass of `%s'", TREE_TYPE (type), + TYPE_NAME_STRING (TREE_TYPE (intype))); + return error_mark_node; + } + if (distance == -1) + { + distance = get_base_distance (TREE_TYPE (intype), + TREE_TYPE (type), 0, &path); + if (distance == -2) + goto ambig; + if (distance < 0) + /* Doesn't need any special help from us. */ + return build1 (NOP_EXPR, type, expr); + + code = MINUS_EXPR; + } + return build_vbase_path (code, type, expr, path, 0); + } + return build1 (NOP_EXPR, type, expr); + } + + return cp_convert_to_pointer (type, expr); +} + +/* We are passing something to a function which requires a reference. + The type we are interested in is in TYPE. The initial + value we have to begin with is in ARG. + + FLAGS controls how we manage access checking. + CHECKCONST controls if we report error messages on const subversion. */ +static tree +build_up_reference (type, arg, flags, checkconst) + tree type, arg; + int flags, checkconst; +{ + tree rval, targ; + int literal_flag = 0; + tree argtype = TREE_TYPE (arg); + tree target_type = TREE_TYPE (type); + tree binfo = NULL_TREE; + + my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); + if ((flags & LOOKUP_PROTECT) + && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) + && IS_AGGR_TYPE (argtype) + && IS_AGGR_TYPE (target_type)) + { + binfo = get_binfo (target_type, argtype, 1); + if (binfo == error_mark_node) + return error_mark_node; + if (binfo == NULL_TREE) + return error_not_base_type (target_type, argtype); + } + + /* Pass along const and volatile down into the type. */ + if (TYPE_READONLY (type) || TYPE_VOLATILE (type)) + target_type = cp_build_type_variant (target_type, TYPE_READONLY (type), + TYPE_VOLATILE (type)); + targ = arg; + if (TREE_CODE (targ) == SAVE_EXPR) + targ = TREE_OPERAND (targ, 0); + while (TREE_CODE (targ) == NOP_EXPR + && (TYPE_MAIN_VARIANT (argtype) + == TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (targ, 0))))) + targ = TREE_OPERAND (targ, 0); + + switch (TREE_CODE (targ)) + { + case INDIRECT_REF: + /* This is a call to a constructor which did not know what it was + initializing until now: it needs to initialize a temporary. */ + if (TREE_HAS_CONSTRUCTOR (targ)) + { + tree temp = build_cplus_new (argtype, TREE_OPERAND (targ, 0), 1); + TREE_HAS_CONSTRUCTOR (targ) = 0; + return build_up_reference (type, temp, flags, 1); + } + /* Let &* cancel out to simplify resulting code. + Also, throw away intervening NOP_EXPRs. */ + arg = TREE_OPERAND (targ, 0); + if (TREE_CODE (arg) == NOP_EXPR || TREE_CODE (arg) == NON_LVALUE_EXPR + || (TREE_CODE (arg) == CONVERT_EXPR && TREE_REFERENCE_EXPR (arg))) + arg = TREE_OPERAND (arg, 0); + + /* in doing a &*, we have to get rid of the const'ness on the pointer + value. Haven't thought about volatile here. Pointers come to mind + here. */ + if (TREE_READONLY (arg)) + { + arg = copy_node (arg); + TREE_READONLY (arg) = 0; + } + + rval = build1 (CONVERT_EXPR, type, arg); + TREE_REFERENCE_EXPR (rval) = 1; + + /* propagate the const flag on something like: + + class Base { + public: + int foo; + }; + + class Derived : public Base { + public: + int bar; + }; + + void func(Base&); + + void func2(const Derived& d) { + func(d); + } + + on the d parameter. The below could have been avoided, if the flags + were down in the tree, not sure why they are not. (mrs) */ + /* The below code may have to be propagated to other parts of this + switch. */ + if (TREE_READONLY (targ) && !TREE_READONLY (arg) + && (TREE_CODE (arg) == PARM_DECL || TREE_CODE (arg) == VAR_DECL) + && TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE + && (TYPE_READONLY (target_type) && checkconst)) + { + arg = copy_node (arg); + TREE_READONLY (arg) = TREE_READONLY (targ); + } + literal_flag = TREE_CONSTANT (arg); + + goto done; + + /* Get this out of a register if we happened to be in one by accident. + Also, build up references to non-lvalues it we must. */ + /* For &x[y], return (&) x+y */ + case ARRAY_REF: + if (mark_addressable (TREE_OPERAND (targ, 0)) == 0) + return error_mark_node; + rval = build_binary_op (PLUS_EXPR, TREE_OPERAND (targ, 0), + TREE_OPERAND (targ, 1), 1); + TREE_TYPE (rval) = type; + if (TREE_CONSTANT (TREE_OPERAND (targ, 1)) + && staticp (TREE_OPERAND (targ, 0))) + TREE_CONSTANT (rval) = 1; + goto done; + + case SCOPE_REF: + /* Could be a reference to a static member. */ + { + tree field = TREE_OPERAND (targ, 1); + if (TREE_STATIC (field)) + { + rval = build1 (ADDR_EXPR, type, field); + literal_flag = 1; + goto done; + } + } + + /* We should have farmed out member pointers above. */ + my_friendly_abort (188); + + case COMPONENT_REF: + rval = build_component_addr (targ, build_pointer_type (argtype), + "attempt to make a reference to bit-field structure member `%s'"); + TREE_TYPE (rval) = type; + literal_flag = staticp (TREE_OPERAND (targ, 0)); + + goto done; + + /* Anything not already handled and not a true memory reference + needs to have a reference built up. Do so silently for + things like integers and return values from function, + but complain if we need a reference to something declared + as `register'. */ + + case RESULT_DECL: + if (staticp (targ)) + literal_flag = 1; + TREE_ADDRESSABLE (targ) = 1; + put_var_into_stack (targ); + break; + + case PARM_DECL: +#if 0 + if (targ == current_class_decl) + { + error ("address of `this' not available"); +/* #if 0 */ + /* This code makes the following core dump the compiler on a sun4, + if the code below is used. + + class e_decl; + class a_decl; + typedef a_decl* a_ref; + + class a_s { + public: + a_s(); + void* append(a_ref& item); + }; + class a_decl { + public: + a_decl (e_decl *parent); + a_s generic_s; + a_s decls; + e_decl* parent; + }; + + class e_decl { + public: + e_decl(); + a_s implementations; + }; + + void foobar(void *); + + a_decl::a_decl(e_decl *parent) { + parent->implementations.append(this); + } + */ + + TREE_ADDRESSABLE (targ) = 1; /* so compiler doesn't die later */ + put_var_into_stack (targ); + break; +/* #else */ + return error_mark_node; +/* #endif */ + } +#endif + /* Fall through. */ + case VAR_DECL: + case CONST_DECL: + if (DECL_REGISTER (targ) && !TREE_ADDRESSABLE (targ) + && !DECL_ARTIFICIAL (targ)) + cp_warning ("address needed to build reference for `%D', which is declared `register'", + targ); + else if (staticp (targ)) + literal_flag = 1; + + TREE_ADDRESSABLE (targ) = 1; + put_var_into_stack (targ); + break; + + case COMPOUND_EXPR: + { + tree real_reference = build_up_reference (type, TREE_OPERAND (targ, 1), + LOOKUP_PROTECT, checkconst); + rval = build (COMPOUND_EXPR, type, TREE_OPERAND (targ, 0), real_reference); + TREE_CONSTANT (rval) = staticp (TREE_OPERAND (targ, 1)); + return rval; + } + + case PREINCREMENT_EXPR: + case PREDECREMENT_EXPR: + case MODIFY_EXPR: + case INIT_EXPR: + { + tree real_reference = build_up_reference (type, TREE_OPERAND (targ, 0), + LOOKUP_PROTECT, checkconst); + rval = build (COMPOUND_EXPR, type, arg, real_reference); + TREE_CONSTANT (rval) = staticp (TREE_OPERAND (targ, 0)); + return rval; + } + + case COND_EXPR: + return build (COND_EXPR, type, + TREE_OPERAND (targ, 0), + build_up_reference (type, TREE_OPERAND (targ, 1), + LOOKUP_PROTECT, checkconst), + build_up_reference (type, TREE_OPERAND (targ, 2), + LOOKUP_PROTECT, checkconst)); + + /* Undo the folding... */ + case MIN_EXPR: + case MAX_EXPR: + return build (COND_EXPR, type, + build (TREE_CODE (targ) == MIN_EXPR ? LT_EXPR : GT_EXPR, + boolean_type_node, TREE_OPERAND (targ, 0), + TREE_OPERAND (targ, 1)), + build_up_reference (type, TREE_OPERAND (targ, 0), + LOOKUP_PROTECT, checkconst), + build_up_reference (type, TREE_OPERAND (targ, 1), + LOOKUP_PROTECT, checkconst)); + + case WITH_CLEANUP_EXPR: + return build (WITH_CLEANUP_EXPR, type, + build_up_reference (type, TREE_OPERAND (targ, 0), + LOOKUP_PROTECT, checkconst), + 0, TREE_OPERAND (targ, 2)); + + case BIND_EXPR: + arg = TREE_OPERAND (targ, 1); + if (arg == NULL_TREE) + { + compiler_error ("({ ... }) expression not expanded when needed for reference"); + return error_mark_node; + } + rval = build1 (ADDR_EXPR, type, arg); + TREE_REFERENCE_EXPR (rval) = 1; + return rval; + + default: + break; + } + + if (TREE_ADDRESSABLE (targ) == 0) + { + tree temp; + + if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (argtype)) + { + temp = build_cplus_new (argtype, targ, 1); + if (TREE_CODE (temp) == WITH_CLEANUP_EXPR) + rval = build (WITH_CLEANUP_EXPR, type, + build1 (ADDR_EXPR, type, TREE_OPERAND (temp, 0)), + 0, TREE_OPERAND (temp, 2)); + else + rval = build1 (ADDR_EXPR, type, temp); + goto done; + } + else + { + temp = get_temp_name (argtype, 0); + if (toplevel_bindings_p ()) + { + /* Give this new temp some rtl and initialize it. */ + DECL_INITIAL (temp) = targ; + TREE_STATIC (temp) = 1; + cp_finish_decl (temp, targ, NULL_TREE, 0, LOOKUP_ONLYCONVERTING); + /* Do this after declaring it static. */ + rval = build_unary_op (ADDR_EXPR, temp, 0); + TREE_TYPE (rval) = type; + literal_flag = TREE_CONSTANT (rval); + goto done; + } + else + { + rval = build_unary_op (ADDR_EXPR, temp, 0); + if (binfo && !BINFO_OFFSET_ZEROP (binfo)) + rval = convert_pointer_to (target_type, rval); + else + TREE_TYPE (rval) = type; + + temp = build (MODIFY_EXPR, argtype, temp, arg); + TREE_SIDE_EFFECTS (temp) = 1; + return build (COMPOUND_EXPR, type, temp, rval); + } + } + } + else + rval = build1 (ADDR_EXPR, type, arg); + + done: + if (TYPE_USES_COMPLEX_INHERITANCE (argtype) + || TYPE_USES_COMPLEX_INHERITANCE (target_type)) + { + TREE_TYPE (rval) = build_pointer_type (argtype); + if (flags & LOOKUP_PROTECT) + rval = convert_pointer_to (target_type, rval); + else + rval + = convert_to_pointer_force (build_pointer_type (target_type), rval); + TREE_TYPE (rval) = type; + if (TREE_CODE (rval) == PLUS_EXPR || TREE_CODE (rval) == MINUS_EXPR) + TREE_TYPE (TREE_OPERAND (rval, 0)) + = TREE_TYPE (TREE_OPERAND (rval, 1)) = type; + } + TREE_CONSTANT (rval) = literal_flag; + return rval; +} + +/* For C++: Only need to do one-level references, but cannot + get tripped up on signed/unsigned differences. + + DECL is either NULL_TREE or the _DECL node for a reference that is being + initialized. It can be error_mark_node if we don't know the _DECL but + we know it's an initialization. */ + +tree +convert_to_reference (reftype, expr, convtype, flags, decl) + tree reftype, expr; + int convtype, flags; + tree decl; +{ + register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); + register tree intype = TREE_TYPE (expr); + tree rval = NULL_TREE; + tree rval_as_conversion = NULL_TREE; + int i; + + if (TREE_CODE (intype) == REFERENCE_TYPE) + my_friendly_abort (364); + + intype = TYPE_MAIN_VARIANT (intype); + + i = comp_target_types (type, intype, 0); + + if (i <= 0 && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) + && ! (flags & LOOKUP_NO_CONVERSION)) + { + /* Look for a user-defined conversion to lvalue that we can use. */ + + rval_as_conversion = build_type_conversion (CONVERT_EXPR, type, expr, 1); + + if (rval_as_conversion && rval_as_conversion != error_mark_node + && real_lvalue_p (rval_as_conversion)) + { + expr = rval_as_conversion; + rval_as_conversion = NULL_TREE; + intype = type; + i = 1; + } + } + + if (((convtype & CONV_STATIC) && i == -1) + || ((convtype & CONV_IMPLICIT) && i == 1)) + { + if (flags & LOOKUP_COMPLAIN) + { + tree ttl = TREE_TYPE (reftype); + tree ttr; + + { + int r = TREE_READONLY (expr); + int v = TREE_THIS_VOLATILE (expr); + ttr = cp_build_type_variant (TREE_TYPE (expr), r, v); + } + + if (! real_lvalue_p (expr) && + (decl == NULL_TREE || ! TYPE_READONLY (ttl))) + { + if (decl) + /* Ensure semantics of [dcl.init.ref] */ + cp_pedwarn ("initialization of non-const `%T' from rvalue `%T'", + reftype, intype); + else + cp_pedwarn ("conversion to `%T' from rvalue `%T'", + reftype, intype); + } + else if (! (convtype & CONV_CONST)) + { + if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr)) + cp_pedwarn ("conversion from `%T' to `%T' discards const", + ttr, reftype); + else if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr)) + cp_pedwarn ("conversion from `%T' to `%T' discards volatile", + ttr, reftype); + } + } + + return build_up_reference (reftype, expr, flags, + ! (convtype & CONV_CONST)); + } + else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) + { + /* When casting an lvalue to a reference type, just convert into + a pointer to the new type and deference it. This is allowed + by San Diego WP section 5.2.9 paragraph 12, though perhaps it + should be done directly (jason). (int &)ri ---> *(int*)&ri */ + + /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they + meant. */ + if (TREE_CODE (intype) == POINTER_TYPE + && (comptypes (TREE_TYPE (intype), type, -1))) + cp_warning ("casting `%T' to `%T' does not dereference pointer", + intype, reftype); + + rval = build_unary_op (ADDR_EXPR, expr, 0); + if (rval != error_mark_node) + rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), rval, 0); + if (rval != error_mark_node) + rval = build1 (NOP_EXPR, reftype, rval); + } + else if (decl) + { + tree rval_as_ctor = NULL_TREE; + + if (rval_as_conversion) + { + if (rval_as_conversion == error_mark_node) + { + cp_error ("conversion from `%T' to `%T' is ambiguous", + intype, reftype); + return error_mark_node; + } + rval_as_conversion = build_up_reference (reftype, rval_as_conversion, + flags, 1); + } + + /* Definitely need to go through a constructor here. */ + if (TYPE_HAS_CONSTRUCTOR (type) + && ! CLASSTYPE_ABSTRACT_VIRTUALS (type) + && (rval = build_method_call + (NULL_TREE, constructor_name_full (type), + build_tree_list (NULL_TREE, expr), TYPE_BINFO (type), + LOOKUP_NO_CONVERSION|LOOKUP_SPECULATIVELY + | LOOKUP_ONLYCONVERTING))) + { + tree init; + + if (toplevel_bindings_p ()) + { + extern tree static_aggregates; + tree t = get_temp_name (type, toplevel_bindings_p ()); + init = build_method_call (t, constructor_name_full (type), + build_tree_list (NULL_TREE, expr), + TYPE_BINFO (type), + LOOKUP_NORMAL|LOOKUP_NO_CONVERSION + | LOOKUP_ONLYCONVERTING); + + if (init == error_mark_node) + return error_mark_node; + + make_decl_rtl (t, NULL_PTR, 1); + static_aggregates = perm_tree_cons (expr, t, static_aggregates); + rval = build_unary_op (ADDR_EXPR, t, 0); + } + else + { + init = build_method_call (NULL_TREE, constructor_name_full (type), + build_tree_list (NULL_TREE, expr), + TYPE_BINFO (type), + LOOKUP_NORMAL|LOOKUP_NO_CONVERSION + |LOOKUP_ONLYCONVERTING); + + if (init == error_mark_node) + return error_mark_node; + + rval = build_cplus_new (type, init, 1); + rval = build_up_reference (reftype, rval, flags, 1); + } + rval_as_ctor = rval; + } + + if (rval_as_ctor && rval_as_conversion) + { + cp_error ("ambiguous conversion from `%T' to `%T'; both user-defined conversion and constructor apply", + intype, reftype); + return error_mark_node; + } + else if (rval_as_ctor) + rval = rval_as_ctor; + else if (rval_as_conversion) + rval = rval_as_conversion; + else if (! IS_AGGR_TYPE (type) && ! IS_AGGR_TYPE (intype)) + { + rval = convert (type, expr); + if (rval == error_mark_node) + return error_mark_node; + + rval = build_up_reference (reftype, rval, flags, 1); + } + + if (rval && ! TYPE_READONLY (TREE_TYPE (reftype))) + cp_pedwarn ("initializing non-const `%T' with `%T' will use a temporary", + reftype, intype); + } + + if (rval) + { + /* If we found a way to convert earlier, then use it. */ + return rval; + } + + my_friendly_assert (TREE_CODE (intype) != OFFSET_TYPE, 189); + + if (flags & LOOKUP_COMPLAIN) + cp_error ("cannot convert type `%T' to type `%T'", intype, reftype); + + if (flags & LOOKUP_SPECULATIVELY) + return NULL_TREE; + + return error_mark_node; +} + +/* We are using a reference VAL for its value. Bash that reference all the + way down to its lowest form. */ +tree +convert_from_reference (val) + tree val; +{ + tree type = TREE_TYPE (val); + + if (TREE_CODE (type) == OFFSET_TYPE) + type = TREE_TYPE (type); + if (TREE_CODE (type) == REFERENCE_TYPE) + return build_indirect_ref (val, NULL_PTR); + return val; +} + +/* See if there is a constructor of type TYPE which will convert + EXPR. The reference manual seems to suggest (8.5.6) that we need + not worry about finding constructors for base classes, then converting + to the derived class. + + MSGP is a pointer to a message that would be an appropriate error + string. If MSGP is NULL, then we are not interested in reporting + errors. */ +tree +convert_to_aggr (type, expr, msgp, protect) + tree type, expr; + char **msgp; + int protect; +{ + tree basetype = type; + tree name = TYPE_IDENTIFIER (basetype); + tree function, fndecl, fntype, parmtypes, parmlist, result; + tree method_name; + enum access_type access; + int can_be_private, can_be_protected; + + if (! TYPE_HAS_CONSTRUCTOR (basetype)) + { + if (msgp) + *msgp = "type `%s' does not have a constructor"; + return error_mark_node; + } + + access = access_public; + can_be_private = 0; + can_be_protected = IDENTIFIER_CLASS_VALUE (name) || name == current_class_name; + + parmlist = build_tree_list (NULL_TREE, expr); + parmtypes = tree_cons (NULL_TREE, TREE_TYPE (expr), void_list_node); + + if (TYPE_USES_VIRTUAL_BASECLASSES (basetype)) + { + parmtypes = tree_cons (NULL_TREE, integer_type_node, parmtypes); + parmlist = tree_cons (NULL_TREE, integer_one_node, parmlist); + } + + /* The type of the first argument will be filled in inside the loop. */ + parmlist = tree_cons (NULL_TREE, integer_zero_node, parmlist); + parmtypes = tree_cons (NULL_TREE, build_pointer_type (basetype), parmtypes); + +#if 0 + method_name = build_decl_overload (name, parmtypes, 1); + + /* constructors are up front. */ + fndecl = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (basetype), 0); + if (TYPE_HAS_DESTRUCTOR (basetype)) + fndecl = DECL_CHAIN (fndecl); + + while (fndecl) + { + if (DECL_ASSEMBLER_NAME (fndecl) == method_name) + { + function = fndecl; + if (protect) + { + if (TREE_PRIVATE (fndecl)) + { + can_be_private = + (basetype == current_class_type + || is_friend (basetype, current_function_decl) + || purpose_member (basetype, DECL_ACCESS (fndecl))); + if (! can_be_private) + goto found; + } + else if (TREE_PROTECTED (fndecl)) + { + if (! can_be_protected) + goto found; + } + } + goto found_and_ok; + } + fndecl = DECL_CHAIN (fndecl); + } +#endif + + /* No exact conversion was found. See if an approximate + one will do. */ + fndecl = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (basetype), 0); + if (TYPE_HAS_DESTRUCTOR (basetype)) + fndecl = DECL_CHAIN (fndecl); + + { + int saw_private = 0; + int saw_protected = 0; + struct candidate *candidates = + (struct candidate *) alloca ((decl_list_length (fndecl)+1) * sizeof (struct candidate)); + struct candidate *cp = candidates; + + while (fndecl) + { + function = fndecl; + cp->h_len = 2; + cp->harshness = (struct harshness_code *) + alloca (3 * sizeof (struct harshness_code)); + + compute_conversion_costs (fndecl, parmlist, cp, 2); + if ((cp->h.code & EVIL_CODE) == 0) + { + cp->u.field = fndecl; + if (protect) + { + if (TREE_PRIVATE (fndecl)) + access = access_private; + else if (TREE_PROTECTED (fndecl)) + access = access_protected; + else + access = access_public; + } + else + access = access_public; + + if (access == access_private + ? (basetype == current_class_type + || is_friend (basetype, cp->function) + || purpose_member (basetype, DECL_ACCESS (fndecl))) + : access == access_protected + ? (can_be_protected + || purpose_member (basetype, DECL_ACCESS (fndecl))) + : 1) + { + if (cp->h.code <= TRIVIAL_CODE) + goto found_and_ok; + cp++; + } + else + { + if (access == access_private) + saw_private = 1; + else + saw_protected = 1; + } + } + fndecl = DECL_CHAIN (fndecl); + } + if (cp - candidates) + { + /* Rank from worst to best. Then cp will point to best one. + Private fields have their bits flipped. For unsigned + numbers, this should make them look very large. + If the best alternate has a (signed) negative value, + then all we ever saw were private members. */ + if (cp - candidates > 1) + qsort (candidates, /* char *base */ + cp - candidates, /* int nel */ + sizeof (struct candidate), /* int width */ + rank_for_overload); /* int (*compar)() */ + + --cp; + if (cp->h.code & EVIL_CODE) + { + if (msgp) + *msgp = "ambiguous type conversion possible for `%s'"; + return error_mark_node; + } + + function = cp->function; + fndecl = cp->u.field; + goto found_and_ok; + } + else if (msgp) + { + if (saw_private) + if (saw_protected) + *msgp = "only private and protected conversions apply"; + else + *msgp = "only private conversions apply"; + else if (saw_protected) + *msgp = "only protected conversions apply"; + else + *msgp = "no appropriate conversion to type `%s'"; + } + return error_mark_node; + } + /* NOTREACHED */ + + found: + if (access == access_private) + if (! can_be_private) + { + if (msgp) + *msgp = TREE_PRIVATE (fndecl) + ? "conversion to type `%s' is private" + : "conversion to type `%s' is from private base class"; + return error_mark_node; + } + if (access == access_protected) + if (! can_be_protected) + { + if (msgp) + *msgp = TREE_PRIVATE (fndecl) + ? "conversion to type `%s' is protected" + : "conversion to type `%s' is from protected base class"; + return error_mark_node; + } + function = fndecl; + found_and_ok: + + /* It will convert, but we don't do anything about it yet. */ + if (msgp == 0) + return NULL_TREE; + + fntype = TREE_TYPE (function); + function = default_conversion (function); + + result = build_nt (CALL_EXPR, function, + convert_arguments (NULL_TREE, TYPE_ARG_TYPES (fntype), + parmlist, NULL_TREE, LOOKUP_NORMAL), + NULL_TREE); + TREE_TYPE (result) = TREE_TYPE (fntype); + TREE_SIDE_EFFECTS (result) = 1; + return result; +} + +/* Call this when we know (for any reason) that expr is not, in fact, + zero. This routine is like convert_pointer_to, but it pays + attention to which specific instance of what type we want to + convert to. This routine should eventually become + convert_to_pointer after all references to convert_to_pointer + are removed. */ +tree +convert_pointer_to_real (binfo, expr) + tree binfo, expr; +{ + register tree intype = TREE_TYPE (expr); + tree ptr_type; + tree type, rval; + + if (TREE_CODE (binfo) == TREE_VEC) + type = BINFO_TYPE (binfo); + else if (IS_AGGR_TYPE (binfo)) + { + type = binfo; + } + else + { + type = binfo; + binfo = NULL_TREE; + } + + ptr_type = build_pointer_type (type); + if (ptr_type == TYPE_MAIN_VARIANT (intype)) + return expr; + + if (intype == error_mark_node) + return error_mark_node; + + my_friendly_assert (!integer_zerop (expr), 191); + + if (TREE_CODE (type) == RECORD_TYPE + && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE + && type != TYPE_MAIN_VARIANT (TREE_TYPE (intype))) + { + tree path; + int distance + = get_base_distance (binfo, TYPE_MAIN_VARIANT (TREE_TYPE (intype)), + 0, &path); + + /* This function shouldn't be called with unqualified arguments + but if it is, give them an error message that they can read. */ + if (distance < 0) + { + cp_error ("cannot convert a pointer of type `%T' to a pointer of type `%T'", + TREE_TYPE (intype), type); + + if (distance == -2) + cp_error ("because `%T' is an ambiguous base class", type); + return error_mark_node; + } + + return build_vbase_path (PLUS_EXPR, ptr_type, expr, path, 1); + } + rval = build1 (NOP_EXPR, ptr_type, + TREE_CODE (expr) == NOP_EXPR ? TREE_OPERAND (expr, 0) : expr); + TREE_CONSTANT (rval) = TREE_CONSTANT (expr); + return rval; +} + +/* Call this when we know (for any reason) that expr is + not, in fact, zero. This routine gets a type out of the first + argument and uses it to search for the type to convert to. If there + is more than one instance of that type in the expr, the conversion is + ambiguous. This routine should eventually go away, and all + callers should use convert_to_pointer_real. */ +tree +convert_pointer_to (binfo, expr) + tree binfo, expr; +{ + tree type; + + if (TREE_CODE (binfo) == TREE_VEC) + type = BINFO_TYPE (binfo); + else if (IS_AGGR_TYPE (binfo)) + type = binfo; + else + type = binfo; + return convert_pointer_to_real (type, expr); +} + +/* Conversion... + + FLAGS indicates how we should behave. */ + +tree +cp_convert (type, expr, convtype, flags) + tree type, expr; + int convtype, flags; +{ + register tree e = expr; + register enum tree_code code = TREE_CODE (type); + + if (TREE_CODE (e) == ERROR_MARK + || TREE_CODE (TREE_TYPE (e)) == ERROR_MARK) + return error_mark_node; + + if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP)) + /* We need a new temporary; don't take this shortcut. */; + else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) + /* Trivial conversion: cv-qualifiers do not matter on rvalues. */ + return fold (build1 (NOP_EXPR, type, e)); + + if (code == VOID_TYPE && (convtype & CONV_STATIC)) + return build1 (CONVERT_EXPR, type, e); + +#if 0 + /* This is incorrect. A truncation can't be stripped this way. + Extensions will be stripped by the use of get_unwidened. */ + if (TREE_CODE (e) == NOP_EXPR) + return convert (type, TREE_OPERAND (e, 0)); +#endif + + /* Just convert to the type of the member. */ + if (code == OFFSET_TYPE) + { + type = TREE_TYPE (type); + code = TREE_CODE (type); + } + +#if 0 + if (code == REFERENCE_TYPE) + return fold (convert_to_reference (type, e, convtype, flags, NULL_TREE)); + else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) + e = convert_from_reference (e); +#endif + + if (TREE_CODE (e) == OFFSET_REF) + e = resolve_offset_ref (e); + + if (TREE_READONLY_DECL_P (e)) + e = decl_constant_value (e); + + if (INTEGRAL_CODE_P (code)) + { + tree intype = TREE_TYPE (e); + enum tree_code form = TREE_CODE (intype); + /* enum = enum, enum = int, enum = float are all errors. */ + if (flag_int_enum_equivalence == 0 + && TREE_CODE (type) == ENUMERAL_TYPE + && ARITHMETIC_TYPE_P (intype) + && ! (convtype & CONV_STATIC)) + { + cp_pedwarn ("conversion from `%#T' to `%#T'", intype, type); + + if (flag_pedantic_errors) + return error_mark_node; + } + if (IS_AGGR_TYPE (intype)) + { + tree rval; + rval = build_type_conversion (CONVERT_EXPR, type, e, 1); + if (rval) + return rval; + if (flags & LOOKUP_COMPLAIN) + cp_error ("`%#T' used where a `%T' was expected", intype, type); + if (flags & LOOKUP_SPECULATIVELY) + return NULL_TREE; + return error_mark_node; + } + if (code == BOOLEAN_TYPE) + return truthvalue_conversion (e); + return fold (convert_to_integer (type, e)); + } + if (code == POINTER_TYPE || code == REFERENCE_TYPE + || TYPE_PTRMEMFUNC_P (type)) + return fold (cp_convert_to_pointer (type, e)); + if (code == REAL_TYPE) + { + if (IS_AGGR_TYPE (TREE_TYPE (e))) + { + tree rval; + rval = build_type_conversion (CONVERT_EXPR, type, e, 1); + if (rval) + return rval; + else + if (flags & LOOKUP_COMPLAIN) + cp_error ("`%#T' used where a floating point value was expected", + TREE_TYPE (e)); + } + return fold (convert_to_real (type, e)); + } + + /* New C++ semantics: since assignment is now based on + memberwise copying, if the rhs type is derived from the + lhs type, then we may still do a conversion. */ + if (IS_AGGR_TYPE_CODE (code)) + { + tree dtype = TREE_TYPE (e); + tree ctor = NULL_TREE; + tree conversion = NULL_TREE; + + dtype = TYPE_MAIN_VARIANT (dtype); + + /* Conversion of object pointers or signature pointers/references + to signature pointers/references. */ + + if (TYPE_LANG_SPECIFIC (type) + && (IS_SIGNATURE_POINTER (type) || IS_SIGNATURE_REFERENCE (type))) + { + tree constructor = build_signature_pointer_constructor (type, expr); + tree sig_ty = SIGNATURE_TYPE (type); + tree sig_ptr; + + if (constructor == error_mark_node) + return error_mark_node; + + sig_ptr = get_temp_name (type, 1); + DECL_INITIAL (sig_ptr) = constructor; + CLEAR_SIGNATURE (sig_ty); + cp_finish_decl (sig_ptr, constructor, NULL_TREE, 0, 0); + SET_SIGNATURE (sig_ty); + TREE_READONLY (sig_ptr) = 1; + + return sig_ptr; + } + + /* Conversion between aggregate types. New C++ semantics allow + objects of derived type to be cast to objects of base type. + Old semantics only allowed this between pointers. + + There may be some ambiguity between using a constructor + vs. using a type conversion operator when both apply. */ + + if (IS_AGGR_TYPE (dtype) && ! DERIVED_FROM_P (type, dtype) + && TYPE_HAS_CONVERSION (dtype)) + conversion = build_type_conversion (CONVERT_EXPR, type, e, 1); + + if (conversion == error_mark_node) + { + if (flags & LOOKUP_COMPLAIN) + error ("ambiguous pointer conversion"); + return conversion; + } + + if (TYPE_HAS_CONSTRUCTOR (type)) + ctor = build_method_call (NULL_TREE, constructor_name_full (type), + build_tree_list (NULL_TREE, e), + TYPE_BINFO (type), + (flags & LOOKUP_NORMAL) | LOOKUP_SPECULATIVELY + | (convtype&CONV_NONCONVERTING ? 0 : LOOKUP_ONLYCONVERTING) + | (conversion ? LOOKUP_NO_CONVERSION : 0)); + + if (ctor == error_mark_node) + { + if (flags & LOOKUP_COMPLAIN) + cp_error ("in conversion to type `%T'", type); + if (flags & LOOKUP_SPECULATIVELY) + return NULL_TREE; + return error_mark_node; + } + + if (conversion && ctor) + { + if (flags & LOOKUP_COMPLAIN) + error ("both constructor and type conversion operator apply"); + if (flags & LOOKUP_SPECULATIVELY) + return NULL_TREE; + return error_mark_node; + } + else if (conversion) + return conversion; + else if (ctor) + { + ctor = build_cplus_new (type, ctor, 0); + return ctor; + } + } + + /* If TYPE or TREE_TYPE (E) is not on the permanent_obstack, + then the it won't be hashed and hence compare as not equal, + even when it is. */ + if (code == ARRAY_TYPE + && TREE_TYPE (TREE_TYPE (e)) == TREE_TYPE (type) + && index_type_equal (TYPE_DOMAIN (TREE_TYPE (e)), TYPE_DOMAIN (type))) + return e; + + if (flags & LOOKUP_COMPLAIN) + cp_error ("conversion from `%T' to non-scalar type `%T' requested", + TREE_TYPE (expr), type); + if (flags & LOOKUP_SPECULATIVELY) + return NULL_TREE; + return error_mark_node; +} + +/* Create an expression whose value is that of EXPR, + converted to type TYPE. The TREE_TYPE of the value + is always TYPE. This function implements all reasonable + conversions; callers should filter out those that are + not permitted by the language being compiled. */ + +tree +convert (type, expr) + tree type, expr; +{ + return cp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); +} + +/* Like convert, except permit conversions to take place which + are not normally allowed due to access restrictions + (such as conversion from sub-type to private super-type). */ +tree +convert_force (type, expr, convtype) + tree type; + tree expr; + int convtype; +{ + register tree e = expr; + register enum tree_code code = TREE_CODE (type); + + if (code == REFERENCE_TYPE) + return fold (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, + NULL_TREE)); + else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) + e = convert_from_reference (e); + + if (code == POINTER_TYPE) + return fold (convert_to_pointer_force (type, e)); + + /* From typeck.c convert_for_assignment */ + if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR + && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE + && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) + || integer_zerop (e) + || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) + && TYPE_PTRMEMFUNC_P (type)) + { + /* compatible pointer to member functions. */ + return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1); + } + + return cp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); +} + +/* Subroutine of build_type_conversion. */ +static tree +build_type_conversion_1 (xtype, basetype, expr, typename, for_sure) + tree xtype, basetype; + tree expr; + tree typename; + int for_sure; +{ + tree rval; + int flags; + + if (for_sure == 0) + flags = LOOKUP_PROTECT|LOOKUP_ONLYCONVERTING; + else + flags = LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING; + + rval = build_method_call (expr, typename, NULL_TREE, NULL_TREE, flags); + if (rval == error_mark_node) + { + if (for_sure == 0) + return NULL_TREE; + return error_mark_node; + } + + if (IS_AGGR_TYPE (TREE_TYPE (rval))) + return rval; + + if (warn_cast_qual + && TREE_TYPE (xtype) + && (TREE_READONLY (TREE_TYPE (TREE_TYPE (rval))) + > TREE_READONLY (TREE_TYPE (xtype)))) + warning ("user-defined conversion casting away `const'"); + return convert (xtype, rval); +} + +/* Convert an aggregate EXPR to type XTYPE. If a conversion + exists, return the attempted conversion. This may + return ERROR_MARK_NODE if the conversion is not + allowed (references private members, etc). + If no conversion exists, NULL_TREE is returned. + + If (FOR_SURE & 1) is non-zero, then we allow this type conversion + to take place immediately. Otherwise, we build a SAVE_EXPR + which can be evaluated if the results are ever needed. + + Changes to this functions should be mirrored in user_harshness. + + FIXME: Ambiguity checking is wrong. Should choose one by the implicit + object parameter, or by the second standard conversion sequence if + that doesn't do it. This will probably wait for an overloading rewrite. + (jason 8/9/95) */ + +tree +build_type_conversion (code, xtype, expr, for_sure) + enum tree_code code; + tree xtype, expr; + int for_sure; +{ + /* C++: check to see if we can convert this aggregate type + into the required type. */ + tree basetype; + tree conv; + tree winner = NULL_TREE; + + if (expr == error_mark_node) + return error_mark_node; + + basetype = TREE_TYPE (expr); + if (TREE_CODE (basetype) == REFERENCE_TYPE) + basetype = TREE_TYPE (basetype); + + basetype = TYPE_MAIN_VARIANT (basetype); + if (! TYPE_LANG_SPECIFIC (basetype) || ! TYPE_HAS_CONVERSION (basetype)) + return NULL_TREE; + + /* Do we have an exact match? */ + { + tree typename = build_typename_overload (xtype); + if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) + return build_type_conversion_1 (xtype, basetype, expr, typename, + for_sure); + } + + /* Nope; try looking for others. */ + for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) + { + if (winner && TREE_PURPOSE (winner) == TREE_PURPOSE (conv)) + continue; + + if (can_convert (xtype, TREE_VALUE (conv))) + { + if (winner) + { + if (for_sure) + { + cp_error ("ambiguous conversion from `%T' to `%T'", basetype, + xtype); + cp_error (" candidate conversions include `%T' and `%T'", + TREE_VALUE (winner), TREE_VALUE (conv)); + } + return NULL_TREE; + } + else + winner = conv; + } + } + + if (winner) + return build_type_conversion_1 (xtype, basetype, expr, + TREE_PURPOSE (winner), for_sure); + + return NULL_TREE; +} + +/* Convert the given EXPR to one of a group of types suitable for use in an + expression. DESIRES is a combination of various WANT_* flags (q.v.) + which indicates which types are suitable. If COMPLAIN is 1, complain + about ambiguity; otherwise, the caller will deal with it. */ + +tree +build_expr_type_conversion (desires, expr, complain) + int desires; + tree expr; + int complain; +{ + tree basetype = TREE_TYPE (expr); + tree conv; + tree winner = NULL_TREE; + + if (TREE_CODE (basetype) == OFFSET_TYPE) + expr = resolve_offset_ref (expr); + expr = convert_from_reference (expr); + basetype = TREE_TYPE (expr); + + if (! IS_AGGR_TYPE (basetype)) + switch (TREE_CODE (basetype)) + { + case INTEGER_TYPE: + if ((desires & WANT_NULL) && TREE_CODE (expr) == INTEGER_CST + && integer_zerop (expr)) + return expr; + /* else fall through... */ + + case BOOLEAN_TYPE: + return (desires & WANT_INT) ? expr : NULL_TREE; + case ENUMERAL_TYPE: + return (desires & WANT_ENUM) ? expr : NULL_TREE; + case REAL_TYPE: + return (desires & WANT_FLOAT) ? expr : NULL_TREE; + case POINTER_TYPE: + return (desires & WANT_POINTER) ? expr : NULL_TREE; + + case FUNCTION_TYPE: + case ARRAY_TYPE: + return (desires & WANT_POINTER) ? default_conversion (expr) + : NULL_TREE; + default: + return NULL_TREE; + } + + if (! TYPE_HAS_CONVERSION (basetype)) + return NULL_TREE; + + for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) + { + int win = 0; + tree candidate; + + if (winner && TREE_PURPOSE (winner) == TREE_PURPOSE (conv)) + continue; + + candidate = TREE_VALUE (conv); + if (TREE_CODE (candidate) == REFERENCE_TYPE) + candidate = TREE_TYPE (candidate); + + switch (TREE_CODE (candidate)) + { + case BOOLEAN_TYPE: + case INTEGER_TYPE: + win = (desires & WANT_INT); break; + case ENUMERAL_TYPE: + win = (desires & WANT_ENUM); break; + case REAL_TYPE: + win = (desires & WANT_FLOAT); break; + case POINTER_TYPE: + win = (desires & WANT_POINTER); break; + } + + if (win) + { + if (winner) + { + if (complain) + { + cp_error ("ambiguous default type conversion from `%T'", + basetype); + cp_error (" candidate conversions include `%T' and `%T'", + TREE_VALUE (winner), TREE_VALUE (conv)); + } + return error_mark_node; + } + else + winner = conv; + } + } + + if (winner) + return build_type_conversion_1 (TREE_VALUE (winner), basetype, expr, + TREE_PURPOSE (winner), 1); + + return NULL_TREE; +} + +/* Must convert two aggregate types to non-aggregate type. + Attempts to find a non-ambiguous, "best" type conversion. + + Return 1 on success, 0 on failure. + + @@ What are the real semantics of this supposed to be??? */ +int +build_default_binary_type_conversion (code, arg1, arg2) + enum tree_code code; + tree *arg1, *arg2; +{ + switch (code) + { + case MULT_EXPR: + case TRUNC_DIV_EXPR: + case CEIL_DIV_EXPR: + case FLOOR_DIV_EXPR: + case ROUND_DIV_EXPR: + case EXACT_DIV_EXPR: + *arg1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); + *arg2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); + break; + + case TRUNC_MOD_EXPR: + case FLOOR_MOD_EXPR: + case LSHIFT_EXPR: + case RSHIFT_EXPR: + case BIT_AND_EXPR: + case BIT_XOR_EXPR: + case BIT_IOR_EXPR: + *arg1 = build_expr_type_conversion (WANT_INT | WANT_ENUM, *arg1, 0); + *arg2 = build_expr_type_conversion (WANT_INT | WANT_ENUM, *arg2, 0); + break; + + case PLUS_EXPR: + { + tree a1, a2, p1, p2; + int wins; + + a1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); + a2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); + p1 = build_expr_type_conversion (WANT_POINTER, *arg1, 0); + p2 = build_expr_type_conversion (WANT_POINTER, *arg2, 0); + + wins = (a1 && a2) + (a1 && p2) + (p1 && a2); + + if (wins > 1) + error ("ambiguous default type conversion for `operator +'"); + + if (a1 && a2) + *arg1 = a1, *arg2 = a2; + else if (a1 && p2) + *arg1 = a1, *arg2 = p2; + else + *arg1 = p1, *arg2 = a2; + break; + } + + case MINUS_EXPR: + { + tree a1, a2, p1, p2; + int wins; + + a1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); + a2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); + p1 = build_expr_type_conversion (WANT_POINTER, *arg1, 0); + p2 = build_expr_type_conversion (WANT_POINTER, *arg2, 0); + + wins = (a1 && a2) + (p1 && p2) + (p1 && a2); + + if (wins > 1) + error ("ambiguous default type conversion for `operator -'"); + + if (a1 && a2) + *arg1 = a1, *arg2 = a2; + else if (p1 && p2) + *arg1 = p1, *arg2 = p2; + else + *arg1 = p1, *arg2 = a2; + break; + } + + case GT_EXPR: + case LT_EXPR: + case GE_EXPR: + case LE_EXPR: + case EQ_EXPR: + case NE_EXPR: + { + tree a1, a2, p1, p2; + int wins; + + a1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); + a2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); + p1 = build_expr_type_conversion (WANT_POINTER | WANT_NULL, *arg1, 0); + p2 = build_expr_type_conversion (WANT_POINTER | WANT_NULL, *arg2, 0); + + wins = (a1 && a2) + (p1 && p2); + + if (wins > 1) + cp_error ("ambiguous default type conversion for `%O'", code); + + if (a1 && a2) + *arg1 = a1, *arg2 = a2; + else + *arg1 = p1, *arg2 = p2; + break; + } + + case TRUTH_ANDIF_EXPR: + case TRUTH_ORIF_EXPR: + *arg1 = convert (boolean_type_node, *arg1); + *arg2 = convert (boolean_type_node, *arg2); + break; + + default: + *arg1 = NULL_TREE; + *arg2 = NULL_TREE; + } + + if (*arg1 == error_mark_node || *arg2 == error_mark_node) + cp_error ("ambiguous default type conversion for `%O'", code); + + if (*arg1 && *arg2) + return 1; + + return 0; +} + +/* Implements integral promotion (4.1) and float->double promotion. */ +tree +type_promotes_to (type) + tree type; +{ + int constp, volatilep; + + if (type == error_mark_node) + return error_mark_node; + + constp = TYPE_READONLY (type); + volatilep = TYPE_VOLATILE (type); + type = TYPE_MAIN_VARIANT (type); + + /* bool always promotes to int (not unsigned), even if it's the same + size. */ + if (type == boolean_type_node) + type = integer_type_node; + + /* Normally convert enums to int, but convert wide enums to something + wider. */ + else if (TREE_CODE (type) == ENUMERAL_TYPE + || type == wchar_type_node) + { + int precision = MAX (TYPE_PRECISION (type), + TYPE_PRECISION (integer_type_node)); + tree totype = type_for_size (precision, 0); + if (TREE_UNSIGNED (type) + && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) + type = type_for_size (precision, 1); + else + type = totype; + } + else if (C_PROMOTING_INTEGER_TYPE_P (type)) + { + /* Traditionally, unsignedness is preserved in default promotions. + Otherwise, retain unsignedness if really not getting bigger. */ + if (TREE_UNSIGNED (type) + && (flag_traditional + || TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))) + type = unsigned_type_node; + else + type = integer_type_node; + } + else if (type == float_type_node) + type = double_type_node; + + return cp_build_type_variant (type, constp, volatilep); +} |