1 /* Language-level data type conversion for GNU C++.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 2011 Free Software Foundation, Inc.
5 Hacked by Michael Tiemann (tiemann@cygnus.com)
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
24 /* This file contains the functions for converting C++ expressions
25 to different data types. The only entry point is `convert'.
26 Every language front end must have a `convert' function
27 but what kind of conversions it does will depend on the language. */
31 #include "coretypes.h"
41 static tree cp_convert_to_pointer (tree, tree);
42 static tree convert_to_pointer_force (tree, tree);
43 static tree build_type_conversion (tree, tree);
44 static tree build_up_reference (tree, tree, int, tree);
45 static void warn_ref_binding (tree, tree, tree);
47 /* Change of width--truncation and extension of integers or reals--
48 is represented with NOP_EXPR. Proper functioning of many things
49 assumes that no other conversions can be NOP_EXPRs.
51 Conversion between integer and pointer is represented with CONVERT_EXPR.
52 Converting integer to real uses FLOAT_EXPR
53 and real to integer uses FIX_TRUNC_EXPR.
55 Here is a list of all the functions that assume that widening and
56 narrowing is always done with a NOP_EXPR:
57 In convert.c, convert_to_integer.
58 In c-typeck.c, build_binary_op_nodefault (boolean ops),
59 and c_common_truthvalue_conversion.
60 In expr.c: expand_expr, for operands of a MULT_EXPR.
61 In fold-const.c: fold.
62 In tree.c: get_narrower and get_unwidened.
64 C++: in multiple-inheritance, converting between pointers may involve
65 adjusting them by a delta stored within the class definition. */
67 /* Subroutines of `convert'. */
69 /* if converting pointer to pointer
70 if dealing with classes, check for derived->base or vice versa
71 else if dealing with method pointers, delegate
73 else if converting class, pass off to build_type_conversion
74 else try C-style pointer conversion. */
77 cp_convert_to_pointer (tree type, tree expr)
79 tree intype = TREE_TYPE (expr);
82 if (intype == error_mark_node)
83 return error_mark_node;
85 if (MAYBE_CLASS_TYPE_P (intype))
87 intype = complete_type (intype);
88 if (!COMPLETE_TYPE_P (intype))
90 error ("can%'t convert from incomplete type %qT to %qT",
92 return error_mark_node;
95 rval = build_type_conversion (type, expr);
98 if (rval == error_mark_node)
99 error ("conversion of %qE from %qT to %qT is ambiguous",
105 /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
106 if (TREE_CODE (type) == POINTER_TYPE
107 && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
108 || VOID_TYPE_P (TREE_TYPE (type))))
110 if (TYPE_PTRMEMFUNC_P (intype)
111 || TREE_CODE (intype) == METHOD_TYPE)
112 return convert_member_func_to_ptr (type, expr);
113 if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
114 return build_nop (type, expr);
115 intype = TREE_TYPE (expr);
118 if (expr == error_mark_node)
119 return error_mark_node;
121 form = TREE_CODE (intype);
123 if (POINTER_TYPE_P (intype))
125 intype = TYPE_MAIN_VARIANT (intype);
127 if (TYPE_MAIN_VARIANT (type) != intype
128 && TREE_CODE (type) == POINTER_TYPE
129 && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
130 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
131 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
132 && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
134 enum tree_code code = PLUS_EXPR;
140 intype_class = TREE_TYPE (intype);
141 type_class = TREE_TYPE (type);
143 same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
144 TYPE_MAIN_VARIANT (type_class));
146 /* Try derived to base conversion. */
148 binfo = lookup_base (intype_class, type_class, ba_check, NULL);
149 if (!same_p && !binfo)
151 /* Try base to derived conversion. */
152 binfo = lookup_base (type_class, intype_class, ba_check, NULL);
155 if (binfo == error_mark_node)
156 return error_mark_node;
160 expr = build_base_path (code, expr, binfo, 0,
161 tf_warning_or_error);
162 /* Add any qualifier conversions. */
163 return build_nop (type, expr);
167 if (TYPE_PTRMEMFUNC_P (type))
169 error ("cannot convert %qE from type %qT to type %qT",
171 return error_mark_node;
174 return build_nop (type, expr);
176 else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
177 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
178 return convert_ptrmem (type, expr, /*allow_inverse_p=*/false,
179 /*c_cast_p=*/false, tf_warning_or_error);
180 else if (TYPE_PTRMEMFUNC_P (intype))
184 if (TREE_CODE (expr) == PTRMEM_CST)
185 return cp_convert_to_pointer (type,
186 PTRMEM_CST_MEMBER (expr));
187 else if (TREE_CODE (expr) == OFFSET_REF)
189 tree object = TREE_OPERAND (expr, 0);
190 return get_member_function_from_ptrfunc (&object,
191 TREE_OPERAND (expr, 1));
194 error ("cannot convert %qE from type %qT to type %qT",
196 return error_mark_node;
199 if (null_ptr_cst_p (expr))
203 if (c_inhibit_evaluation_warnings == 0
204 && !NULLPTR_TYPE_P (TREE_TYPE (expr)))
205 warning (OPT_Wzero_as_null_pointer_constant,
206 "zero as null pointer constant");
208 if (TYPE_PTRMEMFUNC_P (type))
209 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0,
210 /*c_cast_p=*/false, tf_warning_or_error);
212 /* A NULL pointer-to-data-member is represented by -1, not by
214 val = (TYPE_PTRMEM_P (type)
215 ? build_int_cst_type (type, -1)
216 : build_int_cst (type, 0));
218 return (TREE_SIDE_EFFECTS (expr)
219 ? build2 (COMPOUND_EXPR, type, expr, val) : val);
221 else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form))
223 error ("invalid conversion from %qT to %qT", intype, type);
224 return error_mark_node;
227 if (INTEGRAL_CODE_P (form))
229 if (TYPE_PRECISION (intype) == POINTER_SIZE)
230 return build1 (CONVERT_EXPR, type, expr);
231 expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr);
232 /* Modes may be different but sizes should be the same. There
233 is supposed to be some integral type that is the same width
235 gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
236 == GET_MODE_SIZE (TYPE_MODE (type)));
238 return convert_to_pointer (type, expr);
241 if (type_unknown_p (expr))
242 return instantiate_type (type, expr, tf_warning_or_error);
244 error ("cannot convert %qE from type %qT to type %qT",
246 return error_mark_node;
249 /* Like convert, except permit conversions to take place which
250 are not normally allowed due to access restrictions
251 (such as conversion from sub-type to private super-type). */
254 convert_to_pointer_force (tree type, tree expr)
256 tree intype = TREE_TYPE (expr);
257 enum tree_code form = TREE_CODE (intype);
259 if (form == POINTER_TYPE)
261 intype = TYPE_MAIN_VARIANT (intype);
263 if (TYPE_MAIN_VARIANT (type) != intype
264 && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
265 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
266 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
267 && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
269 enum tree_code code = PLUS_EXPR;
272 binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type),
276 binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype),
280 if (binfo == error_mark_node)
281 return error_mark_node;
284 expr = build_base_path (code, expr, binfo, 0,
285 tf_warning_or_error);
286 if (expr == error_mark_node)
287 return error_mark_node;
288 /* Add any qualifier conversions. */
289 if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)),
291 expr = build_nop (type, expr);
297 return cp_convert_to_pointer (type, expr);
300 /* We are passing something to a function which requires a reference.
301 The type we are interested in is in TYPE. The initial
302 value we have to begin with is in ARG.
304 FLAGS controls how we manage access checking.
305 DIRECT_BIND in FLAGS controls how any temporaries are generated.
306 If DIRECT_BIND is set, DECL is the reference we're binding to. */
309 build_up_reference (tree type, tree arg, int flags, tree decl)
312 tree argtype = TREE_TYPE (arg);
313 tree target_type = TREE_TYPE (type);
315 gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
317 if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg))
319 /* Create a new temporary variable. We can't just use a TARGET_EXPR
320 here because it needs to live as long as DECL. */
323 arg = make_temporary_var_for_ref_to_temp (decl, target_type);
325 /* Process the initializer for the declaration. */
326 DECL_INITIAL (arg) = targ;
327 cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE,
328 LOOKUP_ONLYCONVERTING|DIRECT_BIND);
330 else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg))
331 return get_target_expr (arg);
333 /* If we had a way to wrap this up, and say, if we ever needed its
334 address, transform all occurrences of the register, into a memory
335 reference we could win better. */
336 rval = cp_build_addr_expr (arg, tf_warning_or_error);
337 if (rval == error_mark_node)
338 return error_mark_node;
340 if ((flags & LOOKUP_PROTECT)
341 && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type)
342 && MAYBE_CLASS_TYPE_P (argtype)
343 && MAYBE_CLASS_TYPE_P (target_type))
345 /* We go through lookup_base for the access control. */
346 tree binfo = lookup_base (argtype, target_type, ba_check, NULL);
347 if (binfo == error_mark_node)
348 return error_mark_node;
349 if (binfo == NULL_TREE)
350 return error_not_base_type (target_type, argtype);
351 rval = build_base_path (PLUS_EXPR, rval, binfo, 1,
352 tf_warning_or_error);
356 = convert_to_pointer_force (build_pointer_type (target_type), rval);
357 return build_nop (type, rval);
360 /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
361 INTYPE is the original rvalue type and DECL is an optional _DECL node
364 [dcl.init.ref] says that if an rvalue is used to
365 initialize a reference, then the reference must be to a
366 non-volatile const type. */
369 warn_ref_binding (tree reftype, tree intype, tree decl)
371 tree ttl = TREE_TYPE (reftype);
373 if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl))
377 if (CP_TYPE_VOLATILE_P (ttl) && decl)
378 msg = G_("initialization of volatile reference type %q#T from "
379 "rvalue of type %qT");
380 else if (CP_TYPE_VOLATILE_P (ttl))
381 msg = G_("conversion to volatile reference type %q#T "
382 "from rvalue of type %qT");
384 msg = G_("initialization of non-const reference type %q#T from "
385 "rvalue of type %qT");
387 msg = G_("conversion to non-const reference type %q#T from "
388 "rvalue of type %qT");
390 permerror (input_location, msg, reftype, intype);
394 /* For C++: Only need to do one-level references, but cannot
395 get tripped up on signed/unsigned differences.
397 DECL is either NULL_TREE or the _DECL node for a reference that is being
398 initialized. It can be error_mark_node if we don't know the _DECL but
399 we know it's an initialization. */
402 convert_to_reference (tree reftype, tree expr, int convtype,
403 int flags, tree decl)
405 tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype));
407 tree rval = NULL_TREE;
408 tree rval_as_conversion = NULL_TREE;
409 bool can_convert_intype_to_type;
411 if (TREE_CODE (type) == FUNCTION_TYPE
412 && TREE_TYPE (expr) == unknown_type_node)
413 expr = instantiate_type (type, expr,
414 (flags & LOOKUP_COMPLAIN)
415 ? tf_warning_or_error : tf_none);
417 if (expr == error_mark_node)
418 return error_mark_node;
420 intype = TREE_TYPE (expr);
422 gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE);
423 gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE);
425 intype = TYPE_MAIN_VARIANT (intype);
427 can_convert_intype_to_type = can_convert (type, intype);
428 if (!can_convert_intype_to_type
429 && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype)
430 && ! (flags & LOOKUP_NO_CONVERSION))
432 /* Look for a user-defined conversion to lvalue that we can use. */
435 = build_type_conversion (reftype, expr);
437 if (rval_as_conversion && rval_as_conversion != error_mark_node
438 && real_lvalue_p (rval_as_conversion))
440 expr = rval_as_conversion;
441 rval_as_conversion = NULL_TREE;
443 can_convert_intype_to_type = 1;
447 if (((convtype & CONV_STATIC) && can_convert (intype, type))
448 || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type))
450 if (flags & LOOKUP_COMPLAIN)
452 tree ttl = TREE_TYPE (reftype);
453 tree ttr = lvalue_type (expr);
455 if (! real_lvalue_p (expr))
456 warn_ref_binding (reftype, intype, decl);
458 if (! (convtype & CONV_CONST)
459 && !at_least_as_qualified_p (ttl, ttr))
460 permerror (input_location, "conversion from %qT to %qT discards qualifiers",
464 return build_up_reference (reftype, expr, flags, decl);
466 else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr))
468 /* When casting an lvalue to a reference type, just convert into
469 a pointer to the new type and deference it. This is allowed
470 by San Diego WP section 5.2.9 paragraph 12, though perhaps it
471 should be done directly (jason). (int &)ri ---> *(int*)&ri */
473 /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
475 if (TREE_CODE (intype) == POINTER_TYPE
476 && (comptypes (TREE_TYPE (intype), type,
477 COMPARE_BASE | COMPARE_DERIVED)))
478 warning (0, "casting %qT to %qT does not dereference pointer",
481 rval = cp_build_addr_expr (expr, tf_warning_or_error);
482 if (rval != error_mark_node)
483 rval = convert_force (build_pointer_type (TREE_TYPE (reftype)),
485 if (rval != error_mark_node)
486 rval = build1 (NOP_EXPR, reftype, rval);
490 rval = convert_for_initialization (NULL_TREE, type, expr, flags,
491 ICR_CONVERTING, 0, 0,
492 tf_warning_or_error);
493 if (rval == NULL_TREE || rval == error_mark_node)
495 warn_ref_binding (reftype, intype, decl);
496 rval = build_up_reference (reftype, rval, flags, decl);
501 /* If we found a way to convert earlier, then use it. */
505 if (flags & LOOKUP_COMPLAIN)
506 error ("cannot convert type %qT to type %qT", intype, reftype);
508 return error_mark_node;
511 /* We are using a reference VAL for its value. Bash that reference all the
512 way down to its lowest form. */
515 convert_from_reference (tree val)
518 && TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE)
520 tree t = TREE_TYPE (TREE_TYPE (val));
521 tree ref = build1 (INDIRECT_REF, t, val);
524 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
525 so that we get the proper error message if the result is used
526 to assign to. Also, &* is supposed to be a no-op. */
527 TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
528 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
529 TREE_SIDE_EFFECTS (ref)
530 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val));
537 /* Really perform an lvalue-to-rvalue conversion, including copying an
538 argument of class type into a temporary. */
541 force_rvalue (tree expr, tsubst_flags_t complain)
543 tree type = TREE_TYPE (expr);
544 if (MAYBE_CLASS_TYPE_P (type) && TREE_CODE (expr) != TARGET_EXPR)
546 VEC(tree,gc) *args = make_tree_vector_single (expr);
547 expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
548 &args, type, LOOKUP_NORMAL, complain);
549 release_tree_vector (args);
550 expr = build_cplus_new (type, expr, complain);
553 expr = decay_conversion (expr);
559 /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has
560 TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR
564 ignore_overflows (tree expr, tree orig)
566 if (TREE_CODE (expr) == INTEGER_CST
567 && TREE_CODE (orig) == INTEGER_CST
568 && TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig))
570 gcc_assert (!TREE_OVERFLOW (orig));
571 /* Ensure constant sharing. */
572 expr = build_int_cst_wide (TREE_TYPE (expr),
573 TREE_INT_CST_LOW (expr),
574 TREE_INT_CST_HIGH (expr));
579 /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
583 cp_fold_convert (tree type, tree expr)
585 tree conv = fold_convert (type, expr);
586 conv = ignore_overflows (conv, expr);
590 /* C++ conversions, preference to static cast conversions. */
593 cp_convert (tree type, tree expr)
595 return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL);
598 /* C++ equivalent of convert_and_check but using cp_convert as the
601 Convert EXPR to TYPE, warning about conversion problems with constants.
602 Invoke this function on every expression that is converted implicitly,
603 i.e. because of language rules and not because of an explicit cast. */
606 cp_convert_and_check (tree type, tree expr)
610 if (TREE_TYPE (expr) == type)
613 result = cp_convert (type, expr);
615 if (c_inhibit_evaluation_warnings == 0
616 && !TREE_OVERFLOW_P (expr)
617 && result != error_mark_node)
618 warnings_for_convert_and_check (type, expr, result);
625 FLAGS indicates how we should behave. */
628 ocp_convert (tree type, tree expr, int convtype, int flags)
631 enum tree_code code = TREE_CODE (type);
632 const char *invalid_conv_diag;
635 if (error_operand_p (e) || type == error_mark_node)
636 return error_mark_node;
638 complete_type (type);
639 complete_type (TREE_TYPE (expr));
641 if ((invalid_conv_diag
642 = targetm.invalid_conversion (TREE_TYPE (expr), type)))
644 error (invalid_conv_diag);
645 return error_mark_node;
648 /* FIXME remove when moving to c_fully_fold model. */
649 /* FIXME do we still need this test? */
650 if (!CLASS_TYPE_P (type))
651 e = integral_constant_value (e);
652 if (error_operand_p (e))
653 return error_mark_node;
655 if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP))
656 /* We need a new temporary; don't take this shortcut. */;
657 else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e)))
659 if (same_type_p (type, TREE_TYPE (e)))
660 /* The call to fold will not always remove the NOP_EXPR as
661 might be expected, since if one of the types is a typedef;
662 the comparison in fold is just equality of pointers, not a
663 call to comptypes. We don't call fold in this case because
664 that can result in infinite recursion; fold will call
665 convert, which will call ocp_convert, etc. */
667 /* For complex data types, we need to perform componentwise
669 else if (TREE_CODE (type) == COMPLEX_TYPE)
670 return fold_if_not_in_template (convert_to_complex (type, e));
671 else if (TREE_CODE (e) == TARGET_EXPR)
673 /* Don't build a NOP_EXPR of class type. Instead, change the
674 type of the temporary. */
675 TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type;
680 /* We shouldn't be treating objects of ADDRESSABLE type as
682 gcc_assert (!TREE_ADDRESSABLE (type));
683 return fold_if_not_in_template (build_nop (type, e));
687 e1 = targetm.convert_to_type (type, e);
691 if (code == VOID_TYPE && (convtype & CONV_STATIC))
693 e = convert_to_void (e, ICV_CAST, tf_warning_or_error);
697 if (INTEGRAL_CODE_P (code))
699 tree intype = TREE_TYPE (e);
702 if (TREE_CODE (type) == ENUMERAL_TYPE)
704 /* enum = enum, enum = int, enum = float, (enum)pointer are all
706 if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype)
707 || TREE_CODE (intype) == REAL_TYPE)
708 && ! (convtype & CONV_STATIC))
709 || TREE_CODE (intype) == POINTER_TYPE)
711 if (flags & LOOKUP_COMPLAIN)
712 permerror (input_location, "conversion from %q#T to %q#T", intype, type);
714 if (!flag_permissive)
715 return error_mark_node;
718 /* [expr.static.cast]
720 8. A value of integral or enumeration type can be explicitly
721 converted to an enumeration type. The value is unchanged if
722 the original value is within the range of the enumeration
723 values. Otherwise, the resulting enumeration value is
725 if (TREE_CODE (expr) == INTEGER_CST
726 && !int_fits_type_p (expr, ENUM_UNDERLYING_TYPE (type)))
727 warning (OPT_Wconversion,
728 "the result of the conversion is unspecified because "
729 "%qE is outside the range of type %qT",
732 if (MAYBE_CLASS_TYPE_P (intype))
735 rval = build_type_conversion (type, e);
738 if (flags & LOOKUP_COMPLAIN)
739 error ("%q#T used where a %qT was expected", intype, type);
740 return error_mark_node;
742 if (code == BOOLEAN_TYPE)
744 /* We can't implicitly convert a scoped enum to bool, so convert
745 to the underlying type first. */
746 if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC))
747 e = build_nop (ENUM_UNDERLYING_TYPE (intype), e);
748 return cp_truthvalue_conversion (e);
751 converted = fold_if_not_in_template (convert_to_integer (type, e));
753 /* Ignore any integer overflow caused by the conversion. */
754 return ignore_overflows (converted, e);
756 if (NULLPTR_TYPE_P (type) && e && null_ptr_cst_p (e))
758 if (POINTER_TYPE_P (type) || TYPE_PTR_TO_MEMBER_P (type))
759 return fold_if_not_in_template (cp_convert_to_pointer (type, e));
760 if (code == VECTOR_TYPE)
762 tree in_vtype = TREE_TYPE (e);
763 if (MAYBE_CLASS_TYPE_P (in_vtype))
766 ret_val = build_type_conversion (type, e);
769 if (flags & LOOKUP_COMPLAIN)
770 error ("%q#T used where a %qT was expected", in_vtype, type);
771 return error_mark_node;
773 return fold_if_not_in_template (convert_to_vector (type, e));
775 if (code == REAL_TYPE || code == COMPLEX_TYPE)
777 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e)))
780 rval = build_type_conversion (type, e);
784 if (flags & LOOKUP_COMPLAIN)
785 error ("%q#T used where a floating point value was expected",
788 if (code == REAL_TYPE)
789 return fold_if_not_in_template (convert_to_real (type, e));
790 else if (code == COMPLEX_TYPE)
791 return fold_if_not_in_template (convert_to_complex (type, e));
794 /* New C++ semantics: since assignment is now based on
795 memberwise copying, if the rhs type is derived from the
796 lhs type, then we may still do a conversion. */
797 if (RECORD_OR_UNION_CODE_P (code))
799 tree dtype = TREE_TYPE (e);
800 tree ctor = NULL_TREE;
802 dtype = TYPE_MAIN_VARIANT (dtype);
804 /* Conversion between aggregate types. New C++ semantics allow
805 objects of derived type to be cast to objects of base type.
806 Old semantics only allowed this between pointers.
808 There may be some ambiguity between using a constructor
809 vs. using a type conversion operator when both apply. */
813 if (abstract_virtuals_error (NULL_TREE, type))
814 return error_mark_node;
816 if (BRACE_ENCLOSED_INITIALIZER_P (ctor))
817 ctor = perform_implicit_conversion (type, ctor, tf_warning_or_error);
818 else if ((flags & LOOKUP_ONLYCONVERTING)
819 && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype)))
820 /* For copy-initialization, first we create a temp of the proper type
821 with a user-defined conversion sequence, then we direct-initialize
822 the target with the temp (see [dcl.init]). */
823 ctor = build_user_type_conversion (type, ctor, flags);
826 VEC(tree,gc) *ctor_vec = make_tree_vector_single (ctor);
827 ctor = build_special_member_call (NULL_TREE,
828 complete_ctor_identifier,
831 tf_warning_or_error);
832 release_tree_vector (ctor_vec);
835 return build_cplus_new (type, ctor, tf_warning_or_error);
838 if (flags & LOOKUP_COMPLAIN)
840 /* If the conversion failed and expr was an invalid use of pointer to
841 member function, try to report a meaningful error. */
842 if (invalid_nonstatic_memfn_p (expr, tf_warning_or_error))
843 /* We displayed the error message. */;
845 error ("conversion from %qT to non-scalar type %qT requested",
846 TREE_TYPE (expr), type);
848 return error_mark_node;
851 /* When an expression is used in a void context, its value is discarded and
852 no lvalue-rvalue and similar conversions happen [expr.static.cast/4,
853 stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type
854 in a void context. The C++ standard does not define what an `access' to an
855 object is, but there is reason to believe that it is the lvalue to rvalue
856 conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it
857 accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8
858 indicates that volatile semantics should be the same between C and C++
859 where ever possible. C leaves it implementation defined as to what
860 constitutes an access to a volatile. So, we interpret `*vp' as a read of
861 the volatile object `vp' points to, unless that is an incomplete type. For
862 volatile references we do not do this interpretation, because that would
863 make it impossible to ignore the reference return value from functions. We
864 issue warnings in the confusing cases.
866 The IMPLICIT is ICV_CAST when the user is explicitly converting an expression
867 to void via a cast. If an expression is being implicitly converted, IMPLICIT
868 indicates the context of the implicit conversion. */
871 convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
873 if (expr == error_mark_node
874 || TREE_TYPE (expr) == error_mark_node)
875 return error_mark_node;
877 if (implicit == ICV_CAST)
878 mark_exp_read (expr);
883 while (TREE_CODE (exprv) == COMPOUND_EXPR)
884 exprv = TREE_OPERAND (exprv, 1);
886 || handled_component_p (exprv)
887 || TREE_CODE (exprv) == INDIRECT_REF)
888 /* Expr is not being 'used' here, otherwise we whould have
889 called mark_{rl}value_use use here, which would have in turn
890 called mark_exp_read. Rather, we call mark_exp_read directly
891 to avoid some warnings when
892 -Wunused-but-set-{variable,parameter} is in effect. */
893 mark_exp_read (exprv);
896 if (!TREE_TYPE (expr))
898 if (invalid_nonstatic_memfn_p (expr, complain))
899 return error_mark_node;
900 if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
902 if (complain & tf_error)
903 error ("pseudo-destructor is not called");
904 return error_mark_node;
906 if (VOID_TYPE_P (TREE_TYPE (expr)))
908 switch (TREE_CODE (expr))
912 /* The two parts of a cond expr might be separate lvalues. */
913 tree op1 = TREE_OPERAND (expr,1);
914 tree op2 = TREE_OPERAND (expr,2);
915 bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1))
916 || TREE_SIDE_EFFECTS (op2));
917 tree new_op1, new_op2;
919 if (implicit != ICV_CAST && !side_effects)
922 new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
923 new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
928 new_op1 = convert_to_void (op1, ICV_CAST, complain);
929 new_op2 = convert_to_void (op2, ICV_CAST, complain);
932 expr = build3 (COND_EXPR, TREE_TYPE (new_op2),
933 TREE_OPERAND (expr, 0), new_op1, new_op2);
939 /* The second part of a compound expr contains the value. */
940 tree op1 = TREE_OPERAND (expr,1);
942 if (implicit != ICV_CAST && !TREE_NO_WARNING (expr))
943 new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
945 new_op1 = convert_to_void (op1, ICV_CAST, complain);
949 tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
950 TREE_OPERAND (expr, 0), new_op1);
957 case NON_LVALUE_EXPR:
959 /* These have already decayed to rvalue. */
962 case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
967 tree type = TREE_TYPE (expr);
968 int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
970 int is_volatile = TYPE_VOLATILE (type);
971 int is_complete = COMPLETE_TYPE_P (complete_type (type));
973 /* Can't load the value if we don't know the type. */
974 if (is_volatile && !is_complete)
976 if (complain & tf_warning)
980 warning (0, "conversion to void will not access "
981 "object of incomplete type %qT", type);
983 case ICV_SECOND_OF_COND:
984 warning (0, "indirection will not access object of "
985 "incomplete type %qT in second operand "
986 "of conditional expression", type);
988 case ICV_THIRD_OF_COND:
989 warning (0, "indirection will not access object of "
990 "incomplete type %qT in third operand "
991 "of conditional expression", type);
993 case ICV_RIGHT_OF_COMMA:
994 warning (0, "indirection will not access object of "
995 "incomplete type %qT in right operand of "
996 "comma operator", type);
998 case ICV_LEFT_OF_COMMA:
999 warning (0, "indirection will not access object of "
1000 "incomplete type %qT in left operand of "
1001 "comma operator", type);
1004 warning (0, "indirection will not access object of "
1005 "incomplete type %qT in statement", type);
1007 case ICV_THIRD_IN_FOR:
1008 warning (0, "indirection will not access object of "
1009 "incomplete type %qT in for increment "
1010 "expression", type);
1016 /* Don't load the value if this is an implicit dereference, or if
1017 the type needs to be handled by ctors/dtors. */
1018 else if (is_volatile && is_reference)
1020 if (complain & tf_warning)
1024 warning (0, "conversion to void will not access "
1025 "object of type %qT", type);
1027 case ICV_SECOND_OF_COND:
1028 warning (0, "implicit dereference will not access object "
1029 "of type %qT in second operand of "
1030 "conditional expression", type);
1032 case ICV_THIRD_OF_COND:
1033 warning (0, "implicit dereference will not access object "
1034 "of type %qT in third operand of "
1035 "conditional expression", type);
1037 case ICV_RIGHT_OF_COMMA:
1038 warning (0, "implicit dereference will not access object "
1039 "of type %qT in right operand of "
1040 "comma operator", type);
1042 case ICV_LEFT_OF_COMMA:
1043 warning (0, "implicit dereference will not access object "
1044 "of type %qT in left operand of comma operator",
1048 warning (0, "implicit dereference will not access object "
1049 "of type %qT in statement", type);
1051 case ICV_THIRD_IN_FOR:
1052 warning (0, "implicit dereference will not access object "
1053 "of type %qT in for increment expression",
1060 else if (is_volatile && TREE_ADDRESSABLE (type))
1062 if (complain & tf_warning)
1066 warning (0, "conversion to void will not access "
1067 "object of non-trivially-copyable type %qT",
1070 case ICV_SECOND_OF_COND:
1071 warning (0, "indirection will not access object of "
1072 "non-trivially-copyable type %qT in second "
1073 "operand of conditional expression", type);
1075 case ICV_THIRD_OF_COND:
1076 warning (0, "indirection will not access object of "
1077 "non-trivially-copyable type %qT in third "
1078 "operand of conditional expression", type);
1080 case ICV_RIGHT_OF_COMMA:
1081 warning (0, "indirection will not access object of "
1082 "non-trivially-copyable type %qT in right "
1083 "operand of comma operator", type);
1085 case ICV_LEFT_OF_COMMA:
1086 warning (0, "indirection will not access object of "
1087 "non-trivially-copyable type %qT in left "
1088 "operand of comma operator", type);
1091 warning (0, "indirection will not access object of "
1092 "non-trivially-copyable type %qT in statement",
1095 case ICV_THIRD_IN_FOR:
1096 warning (0, "indirection will not access object of "
1097 "non-trivially-copyable type %qT in for "
1098 "increment expression", type);
1104 if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
1106 /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
1107 operation is stripped off. Note that we don't warn about
1108 - an expression with TREE_NO_WARNING set. (For an example of
1109 such expressions, see build_over_call in call.c.)
1110 - automatic dereferencing of references, since the user cannot
1111 control it. (See also warn_if_unused_value() in stmt.c.) */
1112 if (warn_unused_value
1113 && implicit != ICV_CAST
1114 && (complain & tf_warning)
1115 && !TREE_NO_WARNING (expr)
1117 warning (OPT_Wunused_value, "value computed is not used");
1118 expr = TREE_OPERAND (expr, 0);
1126 /* External variables might be incomplete. */
1127 tree type = TREE_TYPE (expr);
1128 int is_complete = COMPLETE_TYPE_P (complete_type (type));
1130 if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
1134 warning (0, "conversion to void will not access "
1135 "object %qE of incomplete type %qT", expr, type);
1137 case ICV_SECOND_OF_COND:
1138 warning (0, "variable %qE of incomplete type %qT will not "
1139 "be accessed in second operand of "
1140 "conditional expression", expr, type);
1142 case ICV_THIRD_OF_COND:
1143 warning (0, "variable %qE of incomplete type %qT will not "
1144 "be accessed in third operand of "
1145 "conditional expression", expr, type);
1147 case ICV_RIGHT_OF_COMMA:
1148 warning (0, "variable %qE of incomplete type %qT will not "
1149 "be accessed in right operand of comma operator",
1152 case ICV_LEFT_OF_COMMA:
1153 warning (0, "variable %qE of incomplete type %qT will not "
1154 "be accessed in left operand of comma operator",
1158 warning (0, "variable %qE of incomplete type %qT will not "
1159 "be accessed in statement", expr, type);
1161 case ICV_THIRD_IN_FOR:
1162 warning (0, "variable %qE of incomplete type %qT will not "
1163 "be accessed in for increment expression",
1174 /* Don't bother with the temporary object returned from a function if
1175 we don't use it and don't need to destroy it. We'll still
1176 allocate space for it in expand_call or declare_return_variable,
1177 but we don't need to track it through all the tree phases. */
1178 if (TARGET_EXPR_IMPLICIT_P (expr)
1179 && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
1181 tree init = TARGET_EXPR_INITIAL (expr);
1182 if (TREE_CODE (init) == AGGR_INIT_EXPR
1183 && !AGGR_INIT_VIA_CTOR_P (init))
1185 tree fn = AGGR_INIT_EXPR_FN (init);
1186 expr = build_call_array_loc (input_location,
1187 TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
1189 aggr_init_expr_nargs (init),
1190 AGGR_INIT_EXPR_ARGP (init));
1197 expr = resolve_nondeduced_context (expr);
1201 if (TREE_CODE (probe) == ADDR_EXPR)
1202 probe = TREE_OPERAND (expr, 0);
1203 if (type_unknown_p (probe))
1205 /* [over.over] enumerates the places where we can take the address
1206 of an overloaded function, and this is not one of them. */
1207 if (complain & tf_error)
1211 error ("conversion to void "
1212 "cannot resolve address of overloaded function");
1214 case ICV_SECOND_OF_COND:
1215 error ("second operand of conditional expression "
1216 "cannot resolve address of overloaded function");
1218 case ICV_THIRD_OF_COND:
1219 error ("third operand of conditional expression "
1220 "cannot resolve address of overloaded function");
1222 case ICV_RIGHT_OF_COMMA:
1223 error ("right operand of comma operator "
1224 "cannot resolve address of overloaded function");
1226 case ICV_LEFT_OF_COMMA:
1227 error ("left operand of comma operator "
1228 "cannot resolve address of overloaded function");
1232 "cannot resolve address of overloaded function");
1234 case ICV_THIRD_IN_FOR:
1235 error ("for increment expression "
1236 "cannot resolve address of overloaded function");
1240 return error_mark_node;
1241 expr = void_zero_node;
1243 else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
1245 /* Only warn when there is no &. */
1246 if (complain & tf_warning)
1249 case ICV_SECOND_OF_COND:
1250 warning (OPT_Waddress,
1251 "second operand of conditional expression "
1252 "is a reference, not call, to function %qE", expr);
1254 case ICV_THIRD_OF_COND:
1255 warning (OPT_Waddress,
1256 "third operand of conditional expression "
1257 "is a reference, not call, to function %qE", expr);
1259 case ICV_RIGHT_OF_COMMA:
1260 warning (OPT_Waddress,
1261 "right operand of comma operator "
1262 "is a reference, not call, to function %qE", expr);
1264 case ICV_LEFT_OF_COMMA:
1265 warning (OPT_Waddress,
1266 "left operand of comma operator "
1267 "is a reference, not call, to function %qE", expr);
1270 warning (OPT_Waddress,
1271 "statement is a reference, not call, to function %qE",
1274 case ICV_THIRD_IN_FOR:
1275 warning (OPT_Waddress,
1276 "for increment expression "
1277 "is a reference, not call, to function %qE", expr);
1283 if (TREE_CODE (expr) == COMPONENT_REF)
1284 expr = TREE_OPERAND (expr, 0);
1288 if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
1290 if (implicit != ICV_CAST
1291 && warn_unused_value
1292 && !TREE_NO_WARNING (expr)
1293 && !processing_template_decl)
1295 /* The middle end does not warn about expressions that have
1296 been explicitly cast to void, so we must do so here. */
1297 if (!TREE_SIDE_EFFECTS (expr)) {
1298 if (complain & tf_warning)
1301 case ICV_SECOND_OF_COND:
1302 warning (OPT_Wunused_value,
1303 "second operand of conditional expression has no effect");
1305 case ICV_THIRD_OF_COND:
1306 warning (OPT_Wunused_value,
1307 "third operand of conditional expression has no effect");
1309 case ICV_RIGHT_OF_COMMA:
1310 warning (OPT_Wunused_value,
1311 "right operand of comma operator has no effect");
1313 case ICV_LEFT_OF_COMMA:
1314 warning (OPT_Wunused_value,
1315 "left operand of comma operator has no effect");
1318 warning (OPT_Wunused_value,
1319 "statement has no effect");
1321 case ICV_THIRD_IN_FOR:
1322 warning (OPT_Wunused_value,
1323 "for increment expression has no effect");
1332 enum tree_code code;
1333 enum tree_code_class tclass;
1336 /* We might like to warn about (say) "(int) f()", as the
1337 cast has no effect, but the compiler itself will
1338 generate implicit conversions under some
1339 circumstances. (For example a block copy will be
1340 turned into a call to "__builtin_memcpy", with a
1341 conversion of the return value to an appropriate
1342 type.) So, to avoid false positives, we strip
1343 conversions. Do not use STRIP_NOPs because it will
1344 not strip conversions to "void", as that is not a
1345 mode-preserving conversion. */
1346 while (TREE_CODE (e) == NOP_EXPR)
1347 e = TREE_OPERAND (e, 0);
1349 code = TREE_CODE (e);
1350 tclass = TREE_CODE_CLASS (code);
1351 if ((tclass == tcc_comparison
1352 || tclass == tcc_unary
1353 || (tclass == tcc_binary
1354 && !(code == MODIFY_EXPR
1355 || code == INIT_EXPR
1356 || code == PREDECREMENT_EXPR
1357 || code == PREINCREMENT_EXPR
1358 || code == POSTDECREMENT_EXPR
1359 || code == POSTINCREMENT_EXPR)))
1360 && (complain & tf_warning))
1361 warning (OPT_Wunused_value, "value computed is not used");
1364 expr = build1 (CONVERT_EXPR, void_type_node, expr);
1366 if (! TREE_SIDE_EFFECTS (expr))
1367 expr = void_zero_node;
1371 /* Create an expression whose value is that of EXPR,
1372 converted to type TYPE. The TREE_TYPE of the value
1373 is always TYPE. This function implements all reasonable
1374 conversions; callers should filter out those that are
1375 not permitted by the language being compiled.
1377 Most of this routine is from build_reinterpret_cast.
1379 The back end cannot call cp_convert (what was convert) because
1380 conversions to/from basetypes may involve memory references
1381 (vbases) and adding or subtracting small values (multiple
1382 inheritance), but it calls convert from the constant folding code
1383 on subtrees of already built trees after it has ripped them apart.
1385 Also, if we ever support range variables, we'll probably also have to
1386 do a little bit more work. */
1389 convert (tree type, tree expr)
1393 if (type == error_mark_node || expr == error_mark_node)
1394 return error_mark_node;
1396 intype = TREE_TYPE (expr);
1398 if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype))
1399 return fold_if_not_in_template (build_nop (type, expr));
1401 return ocp_convert (type, expr, CONV_OLD_CONVERT,
1402 LOOKUP_NORMAL|LOOKUP_NO_CONVERSION);
1405 /* Like cp_convert, except permit conversions to take place which
1406 are not normally allowed due to access restrictions
1407 (such as conversion from sub-type to private super-type). */
1410 convert_force (tree type, tree expr, int convtype)
1413 enum tree_code code = TREE_CODE (type);
1415 if (code == REFERENCE_TYPE)
1416 return (fold_if_not_in_template
1417 (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN,
1420 if (code == POINTER_TYPE)
1421 return fold_if_not_in_template (convert_to_pointer_force (type, e));
1423 /* From typeck.c convert_for_assignment */
1424 if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR
1425 && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE
1426 && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE)
1427 || integer_zerop (e)
1428 || TYPE_PTRMEMFUNC_P (TREE_TYPE (e)))
1429 && TYPE_PTRMEMFUNC_P (type))
1430 /* compatible pointer to member functions. */
1431 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1,
1432 /*c_cast_p=*/1, tf_warning_or_error);
1434 return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL);
1437 /* Convert an aggregate EXPR to type XTYPE. If a conversion
1438 exists, return the attempted conversion. This may
1439 return ERROR_MARK_NODE if the conversion is not
1440 allowed (references private members, etc).
1441 If no conversion exists, NULL_TREE is returned.
1443 FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1444 object parameter, or by the second standard conversion sequence if
1445 that doesn't do it. This will probably wait for an overloading rewrite.
1449 build_type_conversion (tree xtype, tree expr)
1451 /* C++: check to see if we can convert this aggregate type
1452 into the required type. */
1453 return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL);
1456 /* Convert the given EXPR to one of a group of types suitable for use in an
1457 expression. DESIRES is a combination of various WANT_* flags (q.v.)
1458 which indicates which types are suitable. If COMPLAIN is true, complain
1459 about ambiguity; otherwise, the caller will deal with it. */
1462 build_expr_type_conversion (int desires, tree expr, bool complain)
1464 tree basetype = TREE_TYPE (expr);
1465 tree conv = NULL_TREE;
1466 tree winner = NULL_TREE;
1468 if (expr == null_node
1469 && (desires & WANT_INT)
1470 && !(desires & WANT_NULL))
1471 warning_at (input_location, OPT_Wconversion_null,
1472 "converting NULL to non-pointer type");
1474 basetype = TREE_TYPE (expr);
1476 if (basetype == error_mark_node)
1477 return error_mark_node;
1479 if (! MAYBE_CLASS_TYPE_P (basetype))
1480 switch (TREE_CODE (basetype))
1483 if ((desires & WANT_NULL) && null_ptr_cst_p (expr))
1485 /* else fall through... */
1488 return (desires & WANT_INT) ? expr : NULL_TREE;
1490 return (desires & WANT_ENUM) ? expr : NULL_TREE;
1492 return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1494 return (desires & WANT_POINTER) ? expr : NULL_TREE;
1498 return (desires & WANT_POINTER) ? decay_conversion (expr)
1503 if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1505 switch (TREE_CODE (TREE_TYPE (basetype)))
1509 return (desires & WANT_INT) ? expr : NULL_TREE;
1511 return (desires & WANT_ENUM) ? expr : NULL_TREE;
1513 return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1522 /* The code for conversions from class type is currently only used for
1523 delete expressions. Other expressions are handled by build_new_op. */
1524 if (!complete_type_or_maybe_complain (basetype, expr, complain))
1525 return error_mark_node;
1526 if (!TYPE_HAS_CONVERSION (basetype))
1529 for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv))
1533 tree cand = TREE_VALUE (conv);
1534 cand = OVL_CURRENT (cand);
1536 if (winner && winner == cand)
1539 if (DECL_NONCONVERTING_P (cand))
1542 candidate = non_reference (TREE_TYPE (TREE_TYPE (cand)));
1544 switch (TREE_CODE (candidate))
1548 win = (desires & WANT_INT); break;
1550 win = (desires & WANT_ENUM); break;
1552 win = (desires & WANT_FLOAT); break;
1554 win = (desires & WANT_POINTER); break;
1558 if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1560 switch (TREE_CODE (TREE_TYPE (candidate)))
1564 win = (desires & WANT_INT); break;
1566 win = (desires & WANT_ENUM); break;
1568 win = (desires & WANT_FLOAT); break;
1575 /* A wildcard could be instantiated to match any desired
1576 type, but we can't deduce the template argument. */
1577 if (WILDCARD_TYPE_P (candidate))
1584 if (TREE_CODE (cand) == TEMPLATE_DECL)
1587 error ("default type conversion can't deduce template"
1588 " argument for %qD", cand);
1589 return error_mark_node;
1596 error ("ambiguous default type conversion from %qT",
1598 error (" candidate conversions include %qD and %qD",
1601 return error_mark_node;
1610 tree type = non_reference (TREE_TYPE (TREE_TYPE (winner)));
1611 return build_user_type_conversion (type, expr, LOOKUP_NORMAL);
1617 /* Implements integral promotion (4.1) and float->double promotion. */
1620 type_promotes_to (tree type)
1624 if (type == error_mark_node)
1625 return error_mark_node;
1627 type = TYPE_MAIN_VARIANT (type);
1629 /* Check for promotions of target-defined types first. */
1630 promoted_type = targetm.promoted_type (type);
1632 return promoted_type;
1634 /* bool always promotes to int (not unsigned), even if it's the same
1636 if (TREE_CODE (type) == BOOLEAN_TYPE)
1637 type = integer_type_node;
1639 /* Scoped enums don't promote, but pretend they do for backward ABI bug
1640 compatibility wrt varargs. */
1641 else if (SCOPED_ENUM_P (type) && abi_version_at_least (6))
1644 /* Normally convert enums to int, but convert wide enums to something
1646 else if (TREE_CODE (type) == ENUMERAL_TYPE
1647 || type == char16_type_node
1648 || type == char32_type_node
1649 || type == wchar_type_node)
1651 int precision = MAX (TYPE_PRECISION (type),
1652 TYPE_PRECISION (integer_type_node));
1653 tree totype = c_common_type_for_size (precision, 0);
1654 if (SCOPED_ENUM_P (type))
1655 warning (OPT_Wabi, "scoped enum %qT will not promote to an integral "
1656 "type in a future version of GCC", type);
1657 if (TREE_CODE (type) == ENUMERAL_TYPE)
1658 type = ENUM_UNDERLYING_TYPE (type);
1659 if (TYPE_UNSIGNED (type)
1660 && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype))
1661 type = c_common_type_for_size (precision, 1);
1665 else if (c_promoting_integer_type_p (type))
1667 /* Retain unsignedness if really not getting bigger. */
1668 if (TYPE_UNSIGNED (type)
1669 && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1670 type = unsigned_type_node;
1672 type = integer_type_node;
1674 else if (type == float_type_node)
1675 type = double_type_node;
1680 /* The routines below this point are carefully written to conform to
1681 the standard. They use the same terminology, and follow the rules
1682 closely. Although they are used only in pt.c at the moment, they
1683 should presumably be used everywhere in the future. */
1685 /* Attempt to perform qualification conversions on EXPR to convert it
1686 to TYPE. Return the resulting expression, or error_mark_node if
1687 the conversion was impossible. */
1690 perform_qualification_conversions (tree type, tree expr)
1694 expr_type = TREE_TYPE (expr);
1696 if (same_type_p (type, expr_type))
1698 else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type)
1699 && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type)))
1700 return build_nop (type, expr);
1701 else if (TYPE_PTR_TO_MEMBER_P (type)
1702 && TYPE_PTR_TO_MEMBER_P (expr_type)
1703 && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type),
1704 TYPE_PTRMEM_CLASS_TYPE (expr_type))
1705 && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type),
1706 TYPE_PTRMEM_POINTED_TO_TYPE (expr_type)))
1707 return build_nop (type, expr);
1709 return error_mark_node;