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))
201 if (TYPE_PTRMEMFUNC_P (type))
202 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0,
203 /*c_cast_p=*/false, tf_warning_or_error);
205 if (TYPE_PTRMEM_P (type))
207 /* A NULL pointer-to-member is represented by -1, not by
209 expr = build_int_cst_type (type, -1);
212 expr = build_int_cst (type, 0);
216 else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form))
218 error ("invalid conversion from %qT to %qT", intype, type);
219 return error_mark_node;
222 if (INTEGRAL_CODE_P (form))
224 if (TYPE_PRECISION (intype) == POINTER_SIZE)
225 return build1 (CONVERT_EXPR, type, expr);
226 expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr);
227 /* Modes may be different but sizes should be the same. There
228 is supposed to be some integral type that is the same width
230 gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
231 == GET_MODE_SIZE (TYPE_MODE (type)));
233 return convert_to_pointer (type, expr);
236 if (type_unknown_p (expr))
237 return instantiate_type (type, expr, tf_warning_or_error);
239 error ("cannot convert %qE from type %qT to type %qT",
241 return error_mark_node;
244 /* Like convert, except permit conversions to take place which
245 are not normally allowed due to access restrictions
246 (such as conversion from sub-type to private super-type). */
249 convert_to_pointer_force (tree type, tree expr)
251 tree intype = TREE_TYPE (expr);
252 enum tree_code form = TREE_CODE (intype);
254 if (form == POINTER_TYPE)
256 intype = TYPE_MAIN_VARIANT (intype);
258 if (TYPE_MAIN_VARIANT (type) != intype
259 && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
260 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
261 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
262 && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
264 enum tree_code code = PLUS_EXPR;
267 binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type),
271 binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype),
275 if (binfo == error_mark_node)
276 return error_mark_node;
279 expr = build_base_path (code, expr, binfo, 0,
280 tf_warning_or_error);
281 if (expr == error_mark_node)
282 return error_mark_node;
283 /* Add any qualifier conversions. */
284 if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)),
286 expr = build_nop (type, expr);
292 return cp_convert_to_pointer (type, expr);
295 /* We are passing something to a function which requires a reference.
296 The type we are interested in is in TYPE. The initial
297 value we have to begin with is in ARG.
299 FLAGS controls how we manage access checking.
300 DIRECT_BIND in FLAGS controls how any temporaries are generated.
301 If DIRECT_BIND is set, DECL is the reference we're binding to. */
304 build_up_reference (tree type, tree arg, int flags, tree decl)
307 tree argtype = TREE_TYPE (arg);
308 tree target_type = TREE_TYPE (type);
310 gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
312 if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg))
314 /* Create a new temporary variable. We can't just use a TARGET_EXPR
315 here because it needs to live as long as DECL. */
318 arg = make_temporary_var_for_ref_to_temp (decl, target_type);
320 /* Process the initializer for the declaration. */
321 DECL_INITIAL (arg) = targ;
322 cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE,
323 LOOKUP_ONLYCONVERTING|DIRECT_BIND);
325 else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg))
326 return get_target_expr (arg);
328 /* If we had a way to wrap this up, and say, if we ever needed its
329 address, transform all occurrences of the register, into a memory
330 reference we could win better. */
331 rval = cp_build_addr_expr (arg, tf_warning_or_error);
332 if (rval == error_mark_node)
333 return error_mark_node;
335 if ((flags & LOOKUP_PROTECT)
336 && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type)
337 && MAYBE_CLASS_TYPE_P (argtype)
338 && MAYBE_CLASS_TYPE_P (target_type))
340 /* We go through lookup_base for the access control. */
341 tree binfo = lookup_base (argtype, target_type, ba_check, NULL);
342 if (binfo == error_mark_node)
343 return error_mark_node;
344 if (binfo == NULL_TREE)
345 return error_not_base_type (target_type, argtype);
346 rval = build_base_path (PLUS_EXPR, rval, binfo, 1,
347 tf_warning_or_error);
351 = convert_to_pointer_force (build_pointer_type (target_type), rval);
352 return build_nop (type, rval);
355 /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
356 INTYPE is the original rvalue type and DECL is an optional _DECL node
359 [dcl.init.ref] says that if an rvalue is used to
360 initialize a reference, then the reference must be to a
361 non-volatile const type. */
364 warn_ref_binding (tree reftype, tree intype, tree decl)
366 tree ttl = TREE_TYPE (reftype);
368 if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl))
372 if (CP_TYPE_VOLATILE_P (ttl) && decl)
373 msg = G_("initialization of volatile reference type %q#T from "
374 "rvalue of type %qT");
375 else if (CP_TYPE_VOLATILE_P (ttl))
376 msg = G_("conversion to volatile reference type %q#T "
377 "from rvalue of type %qT");
379 msg = G_("initialization of non-const reference type %q#T from "
380 "rvalue of type %qT");
382 msg = G_("conversion to non-const reference type %q#T from "
383 "rvalue of type %qT");
385 permerror (input_location, msg, reftype, intype);
389 /* For C++: Only need to do one-level references, but cannot
390 get tripped up on signed/unsigned differences.
392 DECL is either NULL_TREE or the _DECL node for a reference that is being
393 initialized. It can be error_mark_node if we don't know the _DECL but
394 we know it's an initialization. */
397 convert_to_reference (tree reftype, tree expr, int convtype,
398 int flags, tree decl)
400 tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype));
402 tree rval = NULL_TREE;
403 tree rval_as_conversion = NULL_TREE;
404 bool can_convert_intype_to_type;
406 if (TREE_CODE (type) == FUNCTION_TYPE
407 && TREE_TYPE (expr) == unknown_type_node)
408 expr = instantiate_type (type, expr,
409 (flags & LOOKUP_COMPLAIN)
410 ? tf_warning_or_error : tf_none);
412 if (expr == error_mark_node)
413 return error_mark_node;
415 intype = TREE_TYPE (expr);
417 gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE);
418 gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE);
420 intype = TYPE_MAIN_VARIANT (intype);
422 can_convert_intype_to_type = can_convert (type, intype);
423 if (!can_convert_intype_to_type
424 && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype)
425 && ! (flags & LOOKUP_NO_CONVERSION))
427 /* Look for a user-defined conversion to lvalue that we can use. */
430 = build_type_conversion (reftype, expr);
432 if (rval_as_conversion && rval_as_conversion != error_mark_node
433 && real_lvalue_p (rval_as_conversion))
435 expr = rval_as_conversion;
436 rval_as_conversion = NULL_TREE;
438 can_convert_intype_to_type = 1;
442 if (((convtype & CONV_STATIC) && can_convert (intype, type))
443 || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type))
445 if (flags & LOOKUP_COMPLAIN)
447 tree ttl = TREE_TYPE (reftype);
448 tree ttr = lvalue_type (expr);
450 if (! real_lvalue_p (expr))
451 warn_ref_binding (reftype, intype, decl);
453 if (! (convtype & CONV_CONST)
454 && !at_least_as_qualified_p (ttl, ttr))
455 permerror (input_location, "conversion from %qT to %qT discards qualifiers",
459 return build_up_reference (reftype, expr, flags, decl);
461 else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr))
463 /* When casting an lvalue to a reference type, just convert into
464 a pointer to the new type and deference it. This is allowed
465 by San Diego WP section 5.2.9 paragraph 12, though perhaps it
466 should be done directly (jason). (int &)ri ---> *(int*)&ri */
468 /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
470 if (TREE_CODE (intype) == POINTER_TYPE
471 && (comptypes (TREE_TYPE (intype), type,
472 COMPARE_BASE | COMPARE_DERIVED)))
473 warning (0, "casting %qT to %qT does not dereference pointer",
476 rval = cp_build_addr_expr (expr, tf_warning_or_error);
477 if (rval != error_mark_node)
478 rval = convert_force (build_pointer_type (TREE_TYPE (reftype)),
480 if (rval != error_mark_node)
481 rval = build1 (NOP_EXPR, reftype, rval);
485 rval = convert_for_initialization (NULL_TREE, type, expr, flags,
486 ICR_CONVERTING, 0, 0,
487 tf_warning_or_error);
488 if (rval == NULL_TREE || rval == error_mark_node)
490 warn_ref_binding (reftype, intype, decl);
491 rval = build_up_reference (reftype, rval, flags, decl);
496 /* If we found a way to convert earlier, then use it. */
500 if (flags & LOOKUP_COMPLAIN)
501 error ("cannot convert type %qT to type %qT", intype, reftype);
503 return error_mark_node;
506 /* We are using a reference VAL for its value. Bash that reference all the
507 way down to its lowest form. */
510 convert_from_reference (tree val)
513 && TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE)
515 tree t = TREE_TYPE (TREE_TYPE (val));
516 tree ref = build1 (INDIRECT_REF, t, val);
519 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
520 so that we get the proper error message if the result is used
521 to assign to. Also, &* is supposed to be a no-op. */
522 TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
523 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
524 TREE_SIDE_EFFECTS (ref)
525 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val));
532 /* Really perform an lvalue-to-rvalue conversion, including copying an
533 argument of class type into a temporary. */
536 force_rvalue (tree expr, tsubst_flags_t complain)
538 tree type = TREE_TYPE (expr);
539 if (MAYBE_CLASS_TYPE_P (type) && TREE_CODE (expr) != TARGET_EXPR)
541 VEC(tree,gc) *args = make_tree_vector_single (expr);
542 expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
543 &args, type, LOOKUP_NORMAL, complain);
544 release_tree_vector (args);
545 expr = build_cplus_new (type, expr, complain);
548 expr = decay_conversion (expr);
554 /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has
555 TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR
559 ignore_overflows (tree expr, tree orig)
561 if (TREE_CODE (expr) == INTEGER_CST
562 && TREE_CODE (orig) == INTEGER_CST
563 && TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig))
565 gcc_assert (!TREE_OVERFLOW (orig));
566 /* Ensure constant sharing. */
567 expr = build_int_cst_wide (TREE_TYPE (expr),
568 TREE_INT_CST_LOW (expr),
569 TREE_INT_CST_HIGH (expr));
574 /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
578 cp_fold_convert (tree type, tree expr)
580 tree conv = fold_convert (type, expr);
581 conv = ignore_overflows (conv, expr);
585 /* C++ conversions, preference to static cast conversions. */
588 cp_convert (tree type, tree expr)
590 return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL);
593 /* C++ equivalent of convert_and_check but using cp_convert as the
596 Convert EXPR to TYPE, warning about conversion problems with constants.
597 Invoke this function on every expression that is converted implicitly,
598 i.e. because of language rules and not because of an explicit cast. */
601 cp_convert_and_check (tree type, tree expr)
605 if (TREE_TYPE (expr) == type)
608 result = cp_convert (type, expr);
610 if (c_inhibit_evaluation_warnings == 0
611 && !TREE_OVERFLOW_P (expr)
612 && result != error_mark_node)
613 warnings_for_convert_and_check (type, expr, result);
620 FLAGS indicates how we should behave. */
623 ocp_convert (tree type, tree expr, int convtype, int flags)
626 enum tree_code code = TREE_CODE (type);
627 const char *invalid_conv_diag;
630 if (error_operand_p (e) || type == error_mark_node)
631 return error_mark_node;
633 complete_type (type);
634 complete_type (TREE_TYPE (expr));
636 if ((invalid_conv_diag
637 = targetm.invalid_conversion (TREE_TYPE (expr), type)))
639 error (invalid_conv_diag);
640 return error_mark_node;
643 /* FIXME remove when moving to c_fully_fold model. */
644 /* FIXME do we still need this test? */
645 if (!CLASS_TYPE_P (type))
646 e = integral_constant_value (e);
647 if (error_operand_p (e))
648 return error_mark_node;
650 if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP))
651 /* We need a new temporary; don't take this shortcut. */;
652 else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e)))
654 if (same_type_p (type, TREE_TYPE (e)))
655 /* The call to fold will not always remove the NOP_EXPR as
656 might be expected, since if one of the types is a typedef;
657 the comparison in fold is just equality of pointers, not a
658 call to comptypes. We don't call fold in this case because
659 that can result in infinite recursion; fold will call
660 convert, which will call ocp_convert, etc. */
662 /* For complex data types, we need to perform componentwise
664 else if (TREE_CODE (type) == COMPLEX_TYPE)
665 return fold_if_not_in_template (convert_to_complex (type, e));
666 else if (TREE_CODE (e) == TARGET_EXPR)
668 /* Don't build a NOP_EXPR of class type. Instead, change the
669 type of the temporary. */
670 TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type;
675 /* We shouldn't be treating objects of ADDRESSABLE type as
677 gcc_assert (!TREE_ADDRESSABLE (type));
678 return fold_if_not_in_template (build_nop (type, e));
682 e1 = targetm.convert_to_type (type, e);
686 if (code == VOID_TYPE && (convtype & CONV_STATIC))
688 e = convert_to_void (e, ICV_CAST, tf_warning_or_error);
692 if (INTEGRAL_CODE_P (code))
694 tree intype = TREE_TYPE (e);
697 if (TREE_CODE (type) == ENUMERAL_TYPE)
699 /* enum = enum, enum = int, enum = float, (enum)pointer are all
701 if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype)
702 || TREE_CODE (intype) == REAL_TYPE)
703 && ! (convtype & CONV_STATIC))
704 || TREE_CODE (intype) == POINTER_TYPE)
706 if (flags & LOOKUP_COMPLAIN)
707 permerror (input_location, "conversion from %q#T to %q#T", intype, type);
709 if (!flag_permissive)
710 return error_mark_node;
713 /* [expr.static.cast]
715 8. A value of integral or enumeration type can be explicitly
716 converted to an enumeration type. The value is unchanged if
717 the original value is within the range of the enumeration
718 values. Otherwise, the resulting enumeration value is
720 if (TREE_CODE (expr) == INTEGER_CST
721 && !int_fits_type_p (expr, ENUM_UNDERLYING_TYPE (type)))
722 warning (OPT_Wconversion,
723 "the result of the conversion is unspecified because "
724 "%qE is outside the range of type %qT",
727 if (MAYBE_CLASS_TYPE_P (intype))
730 rval = build_type_conversion (type, e);
733 if (flags & LOOKUP_COMPLAIN)
734 error ("%q#T used where a %qT was expected", intype, type);
735 return error_mark_node;
737 if (code == BOOLEAN_TYPE)
739 /* We can't implicitly convert a scoped enum to bool, so convert
740 to the underlying type first. */
741 if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC))
742 e = build_nop (ENUM_UNDERLYING_TYPE (intype), e);
743 return cp_truthvalue_conversion (e);
746 converted = fold_if_not_in_template (convert_to_integer (type, e));
748 /* Ignore any integer overflow caused by the conversion. */
749 return ignore_overflows (converted, e);
751 if (NULLPTR_TYPE_P (type) && e && null_ptr_cst_p (e))
753 if (POINTER_TYPE_P (type) || TYPE_PTR_TO_MEMBER_P (type))
754 return fold_if_not_in_template (cp_convert_to_pointer (type, e));
755 if (code == VECTOR_TYPE)
757 tree in_vtype = TREE_TYPE (e);
758 if (MAYBE_CLASS_TYPE_P (in_vtype))
761 ret_val = build_type_conversion (type, e);
764 if (flags & LOOKUP_COMPLAIN)
765 error ("%q#T used where a %qT was expected", in_vtype, type);
766 return error_mark_node;
768 return fold_if_not_in_template (convert_to_vector (type, e));
770 if (code == REAL_TYPE || code == COMPLEX_TYPE)
772 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e)))
775 rval = build_type_conversion (type, e);
779 if (flags & LOOKUP_COMPLAIN)
780 error ("%q#T used where a floating point value was expected",
783 if (code == REAL_TYPE)
784 return fold_if_not_in_template (convert_to_real (type, e));
785 else if (code == COMPLEX_TYPE)
786 return fold_if_not_in_template (convert_to_complex (type, e));
789 /* New C++ semantics: since assignment is now based on
790 memberwise copying, if the rhs type is derived from the
791 lhs type, then we may still do a conversion. */
792 if (RECORD_OR_UNION_CODE_P (code))
794 tree dtype = TREE_TYPE (e);
795 tree ctor = NULL_TREE;
797 dtype = TYPE_MAIN_VARIANT (dtype);
799 /* Conversion between aggregate types. New C++ semantics allow
800 objects of derived type to be cast to objects of base type.
801 Old semantics only allowed this between pointers.
803 There may be some ambiguity between using a constructor
804 vs. using a type conversion operator when both apply. */
808 if (abstract_virtuals_error (NULL_TREE, type))
809 return error_mark_node;
811 if (BRACE_ENCLOSED_INITIALIZER_P (ctor))
812 ctor = perform_implicit_conversion (type, ctor, tf_warning_or_error);
813 else if ((flags & LOOKUP_ONLYCONVERTING)
814 && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype)))
815 /* For copy-initialization, first we create a temp of the proper type
816 with a user-defined conversion sequence, then we direct-initialize
817 the target with the temp (see [dcl.init]). */
818 ctor = build_user_type_conversion (type, ctor, flags);
821 VEC(tree,gc) *ctor_vec = make_tree_vector_single (ctor);
822 ctor = build_special_member_call (NULL_TREE,
823 complete_ctor_identifier,
826 tf_warning_or_error);
827 release_tree_vector (ctor_vec);
830 return build_cplus_new (type, ctor, tf_warning_or_error);
833 if (flags & LOOKUP_COMPLAIN)
835 /* If the conversion failed and expr was an invalid use of pointer to
836 member function, try to report a meaningful error. */
837 if (invalid_nonstatic_memfn_p (expr, tf_warning_or_error))
838 /* We displayed the error message. */;
840 error ("conversion from %qT to non-scalar type %qT requested",
841 TREE_TYPE (expr), type);
843 return error_mark_node;
846 /* When an expression is used in a void context, its value is discarded and
847 no lvalue-rvalue and similar conversions happen [expr.static.cast/4,
848 stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type
849 in a void context. The C++ standard does not define what an `access' to an
850 object is, but there is reason to believe that it is the lvalue to rvalue
851 conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it
852 accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8
853 indicates that volatile semantics should be the same between C and C++
854 where ever possible. C leaves it implementation defined as to what
855 constitutes an access to a volatile. So, we interpret `*vp' as a read of
856 the volatile object `vp' points to, unless that is an incomplete type. For
857 volatile references we do not do this interpretation, because that would
858 make it impossible to ignore the reference return value from functions. We
859 issue warnings in the confusing cases.
861 The IMPLICIT is ICV_CAST when the user is explicitly converting an expression
862 to void via a cast. If an expression is being implicitly converted, IMPLICIT
863 indicates the context of the implicit conversion. */
866 convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
868 if (expr == error_mark_node
869 || TREE_TYPE (expr) == error_mark_node)
870 return error_mark_node;
872 if (implicit == ICV_CAST)
873 mark_exp_read (expr);
878 while (TREE_CODE (exprv) == COMPOUND_EXPR)
879 exprv = TREE_OPERAND (exprv, 1);
881 || handled_component_p (exprv)
882 || TREE_CODE (exprv) == INDIRECT_REF)
883 /* Expr is not being 'used' here, otherwise we whould have
884 called mark_{rl}value_use use here, which would have in turn
885 called mark_exp_read. Rather, we call mark_exp_read directly
886 to avoid some warnings when
887 -Wunused-but-set-{variable,parameter} is in effect. */
888 mark_exp_read (exprv);
891 if (!TREE_TYPE (expr))
893 if (invalid_nonstatic_memfn_p (expr, complain))
894 return error_mark_node;
895 if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
897 if (complain & tf_error)
898 error ("pseudo-destructor is not called");
899 return error_mark_node;
901 if (VOID_TYPE_P (TREE_TYPE (expr)))
903 switch (TREE_CODE (expr))
907 /* The two parts of a cond expr might be separate lvalues. */
908 tree op1 = TREE_OPERAND (expr,1);
909 tree op2 = TREE_OPERAND (expr,2);
910 bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1))
911 || TREE_SIDE_EFFECTS (op2));
912 tree new_op1, new_op2;
914 if (implicit != ICV_CAST && !side_effects)
917 new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
918 new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
923 new_op1 = convert_to_void (op1, ICV_CAST, complain);
924 new_op2 = convert_to_void (op2, ICV_CAST, complain);
927 expr = build3 (COND_EXPR, TREE_TYPE (new_op2),
928 TREE_OPERAND (expr, 0), new_op1, new_op2);
934 /* The second part of a compound expr contains the value. */
935 tree op1 = TREE_OPERAND (expr,1);
937 if (implicit != ICV_CAST && !TREE_NO_WARNING (expr))
938 new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
940 new_op1 = convert_to_void (op1, ICV_CAST, complain);
944 tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
945 TREE_OPERAND (expr, 0), new_op1);
952 case NON_LVALUE_EXPR:
954 /* These have already decayed to rvalue. */
957 case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
962 tree type = TREE_TYPE (expr);
963 int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
965 int is_volatile = TYPE_VOLATILE (type);
966 int is_complete = COMPLETE_TYPE_P (complete_type (type));
968 /* Can't load the value if we don't know the type. */
969 if (is_volatile && !is_complete)
971 if (complain & tf_warning)
975 warning (0, "conversion to void will not access "
976 "object of incomplete type %qT", type);
978 case ICV_SECOND_OF_COND:
979 warning (0, "indirection will not access object of "
980 "incomplete type %qT in second operand "
981 "of conditional expression", type);
983 case ICV_THIRD_OF_COND:
984 warning (0, "indirection will not access object of "
985 "incomplete type %qT in third operand "
986 "of conditional expression", type);
988 case ICV_RIGHT_OF_COMMA:
989 warning (0, "indirection will not access object of "
990 "incomplete type %qT in right operand of "
991 "comma operator", type);
993 case ICV_LEFT_OF_COMMA:
994 warning (0, "indirection will not access object of "
995 "incomplete type %qT in left operand of "
996 "comma operator", type);
999 warning (0, "indirection will not access object of "
1000 "incomplete type %qT in statement", type);
1002 case ICV_THIRD_IN_FOR:
1003 warning (0, "indirection will not access object of "
1004 "incomplete type %qT in for increment "
1005 "expression", type);
1011 /* Don't load the value if this is an implicit dereference, or if
1012 the type needs to be handled by ctors/dtors. */
1013 else if (is_volatile && is_reference)
1015 if (complain & tf_warning)
1019 warning (0, "conversion to void will not access "
1020 "object of type %qT", type);
1022 case ICV_SECOND_OF_COND:
1023 warning (0, "implicit dereference will not access object "
1024 "of type %qT in second operand of "
1025 "conditional expression", type);
1027 case ICV_THIRD_OF_COND:
1028 warning (0, "implicit dereference will not access object "
1029 "of type %qT in third operand of "
1030 "conditional expression", type);
1032 case ICV_RIGHT_OF_COMMA:
1033 warning (0, "implicit dereference will not access object "
1034 "of type %qT in right operand of "
1035 "comma operator", type);
1037 case ICV_LEFT_OF_COMMA:
1038 warning (0, "implicit dereference will not access object "
1039 "of type %qT in left operand of comma operator",
1043 warning (0, "implicit dereference will not access object "
1044 "of type %qT in statement", type);
1046 case ICV_THIRD_IN_FOR:
1047 warning (0, "implicit dereference will not access object "
1048 "of type %qT in for increment expression",
1055 else if (is_volatile && TREE_ADDRESSABLE (type))
1057 if (complain & tf_warning)
1061 warning (0, "conversion to void will not access "
1062 "object of non-trivially-copyable type %qT",
1065 case ICV_SECOND_OF_COND:
1066 warning (0, "indirection will not access object of "
1067 "non-trivially-copyable type %qT in second "
1068 "operand of conditional expression", type);
1070 case ICV_THIRD_OF_COND:
1071 warning (0, "indirection will not access object of "
1072 "non-trivially-copyable type %qT in third "
1073 "operand of conditional expression", type);
1075 case ICV_RIGHT_OF_COMMA:
1076 warning (0, "indirection will not access object of "
1077 "non-trivially-copyable type %qT in right "
1078 "operand of comma operator", type);
1080 case ICV_LEFT_OF_COMMA:
1081 warning (0, "indirection will not access object of "
1082 "non-trivially-copyable type %qT in left "
1083 "operand of comma operator", type);
1086 warning (0, "indirection will not access object of "
1087 "non-trivially-copyable type %qT in statement",
1090 case ICV_THIRD_IN_FOR:
1091 warning (0, "indirection will not access object of "
1092 "non-trivially-copyable type %qT in for "
1093 "increment expression", type);
1099 if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
1101 /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
1102 operation is stripped off. Note that we don't warn about
1103 - an expression with TREE_NO_WARNING set. (For an example of
1104 such expressions, see build_over_call in call.c.)
1105 - automatic dereferencing of references, since the user cannot
1106 control it. (See also warn_if_unused_value() in stmt.c.) */
1107 if (warn_unused_value
1108 && implicit != ICV_CAST
1109 && (complain & tf_warning)
1110 && !TREE_NO_WARNING (expr)
1112 warning (OPT_Wunused_value, "value computed is not used");
1113 expr = TREE_OPERAND (expr, 0);
1121 /* External variables might be incomplete. */
1122 tree type = TREE_TYPE (expr);
1123 int is_complete = COMPLETE_TYPE_P (complete_type (type));
1125 if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
1129 warning (0, "conversion to void will not access "
1130 "object %qE of incomplete type %qT", expr, type);
1132 case ICV_SECOND_OF_COND:
1133 warning (0, "variable %qE of incomplete type %qT will not "
1134 "be accessed in second operand of "
1135 "conditional expression", expr, type);
1137 case ICV_THIRD_OF_COND:
1138 warning (0, "variable %qE of incomplete type %qT will not "
1139 "be accessed in third operand of "
1140 "conditional expression", expr, type);
1142 case ICV_RIGHT_OF_COMMA:
1143 warning (0, "variable %qE of incomplete type %qT will not "
1144 "be accessed in right operand of comma operator",
1147 case ICV_LEFT_OF_COMMA:
1148 warning (0, "variable %qE of incomplete type %qT will not "
1149 "be accessed in left operand of comma operator",
1153 warning (0, "variable %qE of incomplete type %qT will not "
1154 "be accessed in statement", expr, type);
1156 case ICV_THIRD_IN_FOR:
1157 warning (0, "variable %qE of incomplete type %qT will not "
1158 "be accessed in for increment expression",
1169 /* Don't bother with the temporary object returned from a function if
1170 we don't use it and don't need to destroy it. We'll still
1171 allocate space for it in expand_call or declare_return_variable,
1172 but we don't need to track it through all the tree phases. */
1173 if (TARGET_EXPR_IMPLICIT_P (expr)
1174 && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
1176 tree init = TARGET_EXPR_INITIAL (expr);
1177 if (TREE_CODE (init) == AGGR_INIT_EXPR
1178 && !AGGR_INIT_VIA_CTOR_P (init))
1180 tree fn = AGGR_INIT_EXPR_FN (init);
1181 expr = build_call_array_loc (input_location,
1182 TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
1184 aggr_init_expr_nargs (init),
1185 AGGR_INIT_EXPR_ARGP (init));
1192 expr = resolve_nondeduced_context (expr);
1196 if (TREE_CODE (probe) == ADDR_EXPR)
1197 probe = TREE_OPERAND (expr, 0);
1198 if (type_unknown_p (probe))
1200 /* [over.over] enumerates the places where we can take the address
1201 of an overloaded function, and this is not one of them. */
1202 if (complain & tf_error)
1206 error ("conversion to void "
1207 "cannot resolve address of overloaded function");
1209 case ICV_SECOND_OF_COND:
1210 error ("second operand of conditional expression "
1211 "cannot resolve address of overloaded function");
1213 case ICV_THIRD_OF_COND:
1214 error ("third operand of conditional expression "
1215 "cannot resolve address of overloaded function");
1217 case ICV_RIGHT_OF_COMMA:
1218 error ("right operand of comma operator "
1219 "cannot resolve address of overloaded function");
1221 case ICV_LEFT_OF_COMMA:
1222 error ("left operand of comma operator "
1223 "cannot resolve address of overloaded function");
1227 "cannot resolve address of overloaded function");
1229 case ICV_THIRD_IN_FOR:
1230 error ("for increment expression "
1231 "cannot resolve address of overloaded function");
1235 return error_mark_node;
1236 expr = void_zero_node;
1238 else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
1240 /* Only warn when there is no &. */
1241 if (complain & tf_warning)
1244 case ICV_SECOND_OF_COND:
1245 warning (OPT_Waddress,
1246 "second operand of conditional expression "
1247 "is a reference, not call, to function %qE", expr);
1249 case ICV_THIRD_OF_COND:
1250 warning (OPT_Waddress,
1251 "third operand of conditional expression "
1252 "is a reference, not call, to function %qE", expr);
1254 case ICV_RIGHT_OF_COMMA:
1255 warning (OPT_Waddress,
1256 "right operand of comma operator "
1257 "is a reference, not call, to function %qE", expr);
1259 case ICV_LEFT_OF_COMMA:
1260 warning (OPT_Waddress,
1261 "left operand of comma operator "
1262 "is a reference, not call, to function %qE", expr);
1265 warning (OPT_Waddress,
1266 "statement is a reference, not call, to function %qE",
1269 case ICV_THIRD_IN_FOR:
1270 warning (OPT_Waddress,
1271 "for increment expression "
1272 "is a reference, not call, to function %qE", expr);
1278 if (TREE_CODE (expr) == COMPONENT_REF)
1279 expr = TREE_OPERAND (expr, 0);
1283 if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
1285 if (implicit != ICV_CAST
1286 && warn_unused_value
1287 && !TREE_NO_WARNING (expr)
1288 && !processing_template_decl)
1290 /* The middle end does not warn about expressions that have
1291 been explicitly cast to void, so we must do so here. */
1292 if (!TREE_SIDE_EFFECTS (expr)) {
1293 if (complain & tf_warning)
1296 case ICV_SECOND_OF_COND:
1297 warning (OPT_Wunused_value,
1298 "second operand of conditional expression has no effect");
1300 case ICV_THIRD_OF_COND:
1301 warning (OPT_Wunused_value,
1302 "third operand of conditional expression has no effect");
1304 case ICV_RIGHT_OF_COMMA:
1305 warning (OPT_Wunused_value,
1306 "right operand of comma operator has no effect");
1308 case ICV_LEFT_OF_COMMA:
1309 warning (OPT_Wunused_value,
1310 "left operand of comma operator has no effect");
1313 warning (OPT_Wunused_value,
1314 "statement has no effect");
1316 case ICV_THIRD_IN_FOR:
1317 warning (OPT_Wunused_value,
1318 "for increment expression has no effect");
1327 enum tree_code code;
1328 enum tree_code_class tclass;
1331 /* We might like to warn about (say) "(int) f()", as the
1332 cast has no effect, but the compiler itself will
1333 generate implicit conversions under some
1334 circumstances. (For example a block copy will be
1335 turned into a call to "__builtin_memcpy", with a
1336 conversion of the return value to an appropriate
1337 type.) So, to avoid false positives, we strip
1338 conversions. Do not use STRIP_NOPs because it will
1339 not strip conversions to "void", as that is not a
1340 mode-preserving conversion. */
1341 while (TREE_CODE (e) == NOP_EXPR)
1342 e = TREE_OPERAND (e, 0);
1344 code = TREE_CODE (e);
1345 tclass = TREE_CODE_CLASS (code);
1346 if ((tclass == tcc_comparison
1347 || tclass == tcc_unary
1348 || (tclass == tcc_binary
1349 && !(code == MODIFY_EXPR
1350 || code == INIT_EXPR
1351 || code == PREDECREMENT_EXPR
1352 || code == PREINCREMENT_EXPR
1353 || code == POSTDECREMENT_EXPR
1354 || code == POSTINCREMENT_EXPR)))
1355 && (complain & tf_warning))
1356 warning (OPT_Wunused_value, "value computed is not used");
1359 expr = build1 (CONVERT_EXPR, void_type_node, expr);
1361 if (! TREE_SIDE_EFFECTS (expr))
1362 expr = void_zero_node;
1366 /* Create an expression whose value is that of EXPR,
1367 converted to type TYPE. The TREE_TYPE of the value
1368 is always TYPE. This function implements all reasonable
1369 conversions; callers should filter out those that are
1370 not permitted by the language being compiled.
1372 Most of this routine is from build_reinterpret_cast.
1374 The back end cannot call cp_convert (what was convert) because
1375 conversions to/from basetypes may involve memory references
1376 (vbases) and adding or subtracting small values (multiple
1377 inheritance), but it calls convert from the constant folding code
1378 on subtrees of already built trees after it has ripped them apart.
1380 Also, if we ever support range variables, we'll probably also have to
1381 do a little bit more work. */
1384 convert (tree type, tree expr)
1388 if (type == error_mark_node || expr == error_mark_node)
1389 return error_mark_node;
1391 intype = TREE_TYPE (expr);
1393 if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype))
1394 return fold_if_not_in_template (build_nop (type, expr));
1396 return ocp_convert (type, expr, CONV_OLD_CONVERT,
1397 LOOKUP_NORMAL|LOOKUP_NO_CONVERSION);
1400 /* Like cp_convert, except permit conversions to take place which
1401 are not normally allowed due to access restrictions
1402 (such as conversion from sub-type to private super-type). */
1405 convert_force (tree type, tree expr, int convtype)
1408 enum tree_code code = TREE_CODE (type);
1410 if (code == REFERENCE_TYPE)
1411 return (fold_if_not_in_template
1412 (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN,
1415 if (code == POINTER_TYPE)
1416 return fold_if_not_in_template (convert_to_pointer_force (type, e));
1418 /* From typeck.c convert_for_assignment */
1419 if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR
1420 && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE
1421 && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE)
1422 || integer_zerop (e)
1423 || TYPE_PTRMEMFUNC_P (TREE_TYPE (e)))
1424 && TYPE_PTRMEMFUNC_P (type))
1425 /* compatible pointer to member functions. */
1426 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1,
1427 /*c_cast_p=*/1, tf_warning_or_error);
1429 return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL);
1432 /* Convert an aggregate EXPR to type XTYPE. If a conversion
1433 exists, return the attempted conversion. This may
1434 return ERROR_MARK_NODE if the conversion is not
1435 allowed (references private members, etc).
1436 If no conversion exists, NULL_TREE is returned.
1438 FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1439 object parameter, or by the second standard conversion sequence if
1440 that doesn't do it. This will probably wait for an overloading rewrite.
1444 build_type_conversion (tree xtype, tree expr)
1446 /* C++: check to see if we can convert this aggregate type
1447 into the required type. */
1448 return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL);
1451 /* Convert the given EXPR to one of a group of types suitable for use in an
1452 expression. DESIRES is a combination of various WANT_* flags (q.v.)
1453 which indicates which types are suitable. If COMPLAIN is true, complain
1454 about ambiguity; otherwise, the caller will deal with it. */
1457 build_expr_type_conversion (int desires, tree expr, bool complain)
1459 tree basetype = TREE_TYPE (expr);
1460 tree conv = NULL_TREE;
1461 tree winner = NULL_TREE;
1463 if (expr == null_node
1464 && (desires & WANT_INT)
1465 && !(desires & WANT_NULL))
1466 warning_at (input_location, OPT_Wconversion_null,
1467 "converting NULL to non-pointer type");
1469 basetype = TREE_TYPE (expr);
1471 if (basetype == error_mark_node)
1472 return error_mark_node;
1474 if (! MAYBE_CLASS_TYPE_P (basetype))
1475 switch (TREE_CODE (basetype))
1478 if ((desires & WANT_NULL) && null_ptr_cst_p (expr))
1480 /* else fall through... */
1483 return (desires & WANT_INT) ? expr : NULL_TREE;
1485 return (desires & WANT_ENUM) ? expr : NULL_TREE;
1487 return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1489 return (desires & WANT_POINTER) ? expr : NULL_TREE;
1493 return (desires & WANT_POINTER) ? decay_conversion (expr)
1498 if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1500 switch (TREE_CODE (TREE_TYPE (basetype)))
1504 return (desires & WANT_INT) ? expr : NULL_TREE;
1506 return (desires & WANT_ENUM) ? expr : NULL_TREE;
1508 return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1517 /* The code for conversions from class type is currently only used for
1518 delete expressions. Other expressions are handled by build_new_op. */
1519 if (!complete_type_or_maybe_complain (basetype, expr, complain))
1520 return error_mark_node;
1521 if (!TYPE_HAS_CONVERSION (basetype))
1524 for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv))
1528 tree cand = TREE_VALUE (conv);
1529 cand = OVL_CURRENT (cand);
1531 if (winner && winner == cand)
1534 if (DECL_NONCONVERTING_P (cand))
1537 candidate = non_reference (TREE_TYPE (TREE_TYPE (cand)));
1539 switch (TREE_CODE (candidate))
1543 win = (desires & WANT_INT); break;
1545 win = (desires & WANT_ENUM); break;
1547 win = (desires & WANT_FLOAT); break;
1549 win = (desires & WANT_POINTER); break;
1553 if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1555 switch (TREE_CODE (TREE_TYPE (candidate)))
1559 win = (desires & WANT_INT); break;
1561 win = (desires & WANT_ENUM); break;
1563 win = (desires & WANT_FLOAT); break;
1579 error ("ambiguous default type conversion from %qT",
1581 error (" candidate conversions include %qD and %qD",
1584 return error_mark_node;
1593 tree type = non_reference (TREE_TYPE (TREE_TYPE (winner)));
1594 return build_user_type_conversion (type, expr, LOOKUP_NORMAL);
1600 /* Implements integral promotion (4.1) and float->double promotion. */
1603 type_promotes_to (tree type)
1607 if (type == error_mark_node)
1608 return error_mark_node;
1610 type = TYPE_MAIN_VARIANT (type);
1612 /* Check for promotions of target-defined types first. */
1613 promoted_type = targetm.promoted_type (type);
1615 return promoted_type;
1617 /* bool always promotes to int (not unsigned), even if it's the same
1619 if (TREE_CODE (type) == BOOLEAN_TYPE)
1620 type = integer_type_node;
1622 /* Scoped enums don't promote, but pretend they do for backward ABI bug
1623 compatibility wrt varargs. */
1624 else if (SCOPED_ENUM_P (type) && abi_version_at_least (6))
1627 /* Normally convert enums to int, but convert wide enums to something
1629 else if (TREE_CODE (type) == ENUMERAL_TYPE
1630 || type == char16_type_node
1631 || type == char32_type_node
1632 || type == wchar_type_node)
1634 int precision = MAX (TYPE_PRECISION (type),
1635 TYPE_PRECISION (integer_type_node));
1636 tree totype = c_common_type_for_size (precision, 0);
1637 if (SCOPED_ENUM_P (type))
1638 warning (OPT_Wabi, "scoped enum %qT will not promote to an integral "
1639 "type in a future version of GCC", type);
1640 if (TREE_CODE (type) == ENUMERAL_TYPE)
1641 type = ENUM_UNDERLYING_TYPE (type);
1642 if (TYPE_UNSIGNED (type)
1643 && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype))
1644 type = c_common_type_for_size (precision, 1);
1648 else if (c_promoting_integer_type_p (type))
1650 /* Retain unsignedness if really not getting bigger. */
1651 if (TYPE_UNSIGNED (type)
1652 && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1653 type = unsigned_type_node;
1655 type = integer_type_node;
1657 else if (type == float_type_node)
1658 type = double_type_node;
1663 /* The routines below this point are carefully written to conform to
1664 the standard. They use the same terminology, and follow the rules
1665 closely. Although they are used only in pt.c at the moment, they
1666 should presumably be used everywhere in the future. */
1668 /* Attempt to perform qualification conversions on EXPR to convert it
1669 to TYPE. Return the resulting expression, or error_mark_node if
1670 the conversion was impossible. */
1673 perform_qualification_conversions (tree type, tree expr)
1677 expr_type = TREE_TYPE (expr);
1679 if (same_type_p (type, expr_type))
1681 else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type)
1682 && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type)))
1683 return build_nop (type, expr);
1684 else if (TYPE_PTR_TO_MEMBER_P (type)
1685 && TYPE_PTR_TO_MEMBER_P (expr_type)
1686 && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type),
1687 TYPE_PTRMEM_CLASS_TYPE (expr_type))
1688 && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type),
1689 TYPE_PTRMEM_POINTED_TO_TYPE (expr_type)))
1690 return build_nop (type, expr);
1692 return error_mark_node;