1 /* Language-level data type conversion for GNU C++.
2 Copyright (C) 1987-2013 Free Software Foundation, Inc.
3 Hacked by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 /* This file contains the functions for converting C++ expressions
23 to different data types. The only entry point is `convert'.
24 Every language front end must have a `convert' function
25 but what kind of conversions it does will depend on the language. */
29 #include "coretypes.h"
39 static tree cp_convert_to_pointer (tree, tree, tsubst_flags_t);
40 static tree convert_to_pointer_force (tree, tree, tsubst_flags_t);
41 static tree build_type_conversion (tree, tree);
42 static tree build_up_reference (tree, tree, int, tree, tsubst_flags_t);
43 static void warn_ref_binding (location_t, tree, tree, tree);
45 /* Change of width--truncation and extension of integers or reals--
46 is represented with NOP_EXPR. Proper functioning of many things
47 assumes that no other conversions can be NOP_EXPRs.
49 Conversion between integer and pointer is represented with CONVERT_EXPR.
50 Converting integer to real uses FLOAT_EXPR
51 and real to integer uses FIX_TRUNC_EXPR.
53 Here is a list of all the functions that assume that widening and
54 narrowing is always done with a NOP_EXPR:
55 In convert.c, convert_to_integer.
56 In c-typeck.c, build_binary_op_nodefault (boolean ops),
57 and c_common_truthvalue_conversion.
58 In expr.c: expand_expr, for operands of a MULT_EXPR.
59 In fold-const.c: fold.
60 In tree.c: get_narrower and get_unwidened.
62 C++: in multiple-inheritance, converting between pointers may involve
63 adjusting them by a delta stored within the class definition. */
65 /* Subroutines of `convert'. */
67 /* if converting pointer to pointer
68 if dealing with classes, check for derived->base or vice versa
69 else if dealing with method pointers, delegate
71 else if converting class, pass off to build_type_conversion
72 else try C-style pointer conversion. */
75 cp_convert_to_pointer (tree type, tree expr, tsubst_flags_t complain)
77 tree intype = TREE_TYPE (expr);
80 location_t loc = EXPR_LOC_OR_HERE (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 if (complain & tf_error)
91 error_at (loc, "can%'t convert from incomplete type %qT to %qT",
93 return error_mark_node;
96 rval = build_type_conversion (type, expr);
99 if ((complain & tf_error)
100 && rval == error_mark_node)
101 error_at (loc, "conversion of %qE from %qT to %qT is ambiguous",
107 /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
108 if (TREE_CODE (type) == POINTER_TYPE
109 && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
110 || VOID_TYPE_P (TREE_TYPE (type))))
112 if (TYPE_PTRMEMFUNC_P (intype)
113 || TREE_CODE (intype) == METHOD_TYPE)
114 return convert_member_func_to_ptr (type, expr, complain);
115 if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
116 return build_nop (type, expr);
117 intype = TREE_TYPE (expr);
120 if (expr == error_mark_node)
121 return error_mark_node;
123 form = TREE_CODE (intype);
125 if (POINTER_TYPE_P (intype))
127 intype = TYPE_MAIN_VARIANT (intype);
129 if (TYPE_MAIN_VARIANT (type) != intype
130 && TREE_CODE (type) == POINTER_TYPE
131 && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
132 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
133 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
134 && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
136 enum tree_code code = PLUS_EXPR;
142 intype_class = TREE_TYPE (intype);
143 type_class = TREE_TYPE (type);
145 same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
146 TYPE_MAIN_VARIANT (type_class));
148 /* Try derived to base conversion. */
150 binfo = lookup_base (intype_class, type_class, ba_check,
152 if (!same_p && !binfo)
154 /* Try base to derived conversion. */
155 binfo = lookup_base (type_class, intype_class, ba_check,
159 if (binfo == error_mark_node)
160 return error_mark_node;
164 expr = build_base_path (code, expr, binfo, 0, complain);
165 /* Add any qualifier conversions. */
166 return build_nop (type, expr);
170 if (TYPE_PTRMEMFUNC_P (type))
172 if (complain & tf_error)
173 error_at (loc, "cannot convert %qE from type %qT to type %qT",
175 return error_mark_node;
178 return build_nop (type, expr);
180 else if ((TYPE_PTRDATAMEM_P (type) && TYPE_PTRDATAMEM_P (intype))
181 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
182 return convert_ptrmem (type, expr, /*allow_inverse_p=*/false,
183 /*c_cast_p=*/false, complain);
184 else if (TYPE_PTRMEMFUNC_P (intype))
188 if (TREE_CODE (expr) == PTRMEM_CST)
189 return cp_convert_to_pointer (type, PTRMEM_CST_MEMBER (expr),
191 else if (TREE_CODE (expr) == OFFSET_REF)
193 tree object = TREE_OPERAND (expr, 0);
194 return get_member_function_from_ptrfunc (&object,
195 TREE_OPERAND (expr, 1),
199 error_at (loc, "cannot convert %qE from type %qT to type %qT",
201 return error_mark_node;
204 if (null_ptr_cst_p (expr))
206 if (complain & tf_warning)
207 maybe_warn_zero_as_null_pointer_constant (expr, loc);
209 if (TYPE_PTRMEMFUNC_P (type))
210 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0,
211 /*c_cast_p=*/false, complain);
213 /* A NULL pointer-to-data-member is represented by -1, not by
215 tree val = (TYPE_PTRDATAMEM_P (type)
216 ? build_int_cst_type (type, -1)
217 : build_int_cst (type, 0));
219 return (TREE_SIDE_EFFECTS (expr)
220 ? build2 (COMPOUND_EXPR, type, expr, val) : val);
222 else if (TYPE_PTRMEM_P (type) && INTEGRAL_CODE_P (form))
224 if (complain & tf_error)
225 error_at (loc, "invalid conversion from %qT to %qT", intype, type);
226 return error_mark_node;
229 if (INTEGRAL_CODE_P (form))
231 if (TYPE_PRECISION (intype) == POINTER_SIZE)
232 return build1 (CONVERT_EXPR, type, expr);
233 expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr,
235 /* Modes may be different but sizes should be the same. There
236 is supposed to be some integral type that is the same width
238 gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
239 == GET_MODE_SIZE (TYPE_MODE (type)));
241 return convert_to_pointer (type, expr);
244 if (type_unknown_p (expr))
245 return instantiate_type (type, expr, complain);
247 if (complain & tf_error)
248 error_at (loc, "cannot convert %qE from type %qT to type %qT",
250 return error_mark_node;
253 /* Like convert, except permit conversions to take place which
254 are not normally allowed due to access restrictions
255 (such as conversion from sub-type to private super-type). */
258 convert_to_pointer_force (tree type, tree expr, tsubst_flags_t complain)
260 tree intype = TREE_TYPE (expr);
261 enum tree_code form = TREE_CODE (intype);
263 if (form == POINTER_TYPE)
265 intype = TYPE_MAIN_VARIANT (intype);
267 if (TYPE_MAIN_VARIANT (type) != intype
268 && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
269 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
270 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
271 && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
273 enum tree_code code = PLUS_EXPR;
276 binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type),
277 ba_unique, NULL, complain);
280 binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype),
281 ba_unique, NULL, complain);
284 if (binfo == error_mark_node)
285 return error_mark_node;
288 expr = build_base_path (code, expr, binfo, 0, complain);
289 if (expr == error_mark_node)
290 return error_mark_node;
291 /* Add any qualifier conversions. */
292 if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)),
294 expr = build_nop (type, expr);
300 return cp_convert_to_pointer (type, expr, complain);
303 /* We are passing something to a function which requires a reference.
304 The type we are interested in is in TYPE. The initial
305 value we have to begin with is in ARG.
307 FLAGS controls how we manage access checking.
308 DIRECT_BIND in FLAGS controls how any temporaries are generated.
309 If DIRECT_BIND is set, DECL is the reference we're binding to. */
312 build_up_reference (tree type, tree arg, int flags, tree decl,
313 tsubst_flags_t complain)
316 tree argtype = TREE_TYPE (arg);
317 tree target_type = TREE_TYPE (type);
319 gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
321 if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg))
323 /* Create a new temporary variable. We can't just use a TARGET_EXPR
324 here because it needs to live as long as DECL. */
327 arg = make_temporary_var_for_ref_to_temp (decl, target_type);
329 /* Process the initializer for the declaration. */
330 DECL_INITIAL (arg) = targ;
331 cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE,
332 LOOKUP_ONLYCONVERTING|DIRECT_BIND);
334 else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg))
335 return get_target_expr_sfinae (arg, complain);
337 /* If we had a way to wrap this up, and say, if we ever needed its
338 address, transform all occurrences of the register, into a memory
339 reference we could win better. */
340 rval = cp_build_addr_expr (arg, complain);
341 if (rval == error_mark_node)
342 return error_mark_node;
344 if ((flags & LOOKUP_PROTECT)
345 && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type)
346 && MAYBE_CLASS_TYPE_P (argtype)
347 && MAYBE_CLASS_TYPE_P (target_type))
349 /* We go through lookup_base for the access control. */
350 tree binfo = lookup_base (argtype, target_type, ba_check,
352 if (binfo == error_mark_node)
353 return error_mark_node;
354 if (binfo == NULL_TREE)
355 return error_not_base_type (target_type, argtype);
356 rval = build_base_path (PLUS_EXPR, rval, binfo, 1, complain);
360 = convert_to_pointer_force (build_pointer_type (target_type),
362 return build_nop (type, rval);
365 /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
366 INTYPE is the original rvalue type and DECL is an optional _DECL node
369 [dcl.init.ref] says that if an rvalue is used to
370 initialize a reference, then the reference must be to a
371 non-volatile const type. */
374 warn_ref_binding (location_t loc, tree reftype, tree intype, tree decl)
376 tree ttl = TREE_TYPE (reftype);
378 if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl))
382 if (CP_TYPE_VOLATILE_P (ttl) && decl)
383 msg = G_("initialization of volatile reference type %q#T from "
384 "rvalue of type %qT");
385 else if (CP_TYPE_VOLATILE_P (ttl))
386 msg = G_("conversion to volatile reference type %q#T "
387 "from rvalue of type %qT");
389 msg = G_("initialization of non-const reference type %q#T from "
390 "rvalue of type %qT");
392 msg = G_("conversion to non-const reference type %q#T from "
393 "rvalue of type %qT");
395 permerror (loc, msg, reftype, intype);
399 /* For C++: Only need to do one-level references, but cannot
400 get tripped up on signed/unsigned differences.
402 DECL is either NULL_TREE or the _DECL node for a reference that is being
403 initialized. It can be error_mark_node if we don't know the _DECL but
404 we know it's an initialization. */
407 convert_to_reference (tree reftype, tree expr, int convtype,
408 int flags, tree decl, tsubst_flags_t complain)
410 tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype));
412 tree rval = NULL_TREE;
413 tree rval_as_conversion = NULL_TREE;
414 bool can_convert_intype_to_type;
415 location_t loc = EXPR_LOC_OR_HERE (expr);
417 if (TREE_CODE (type) == FUNCTION_TYPE
418 && TREE_TYPE (expr) == unknown_type_node)
419 expr = instantiate_type (type, expr, complain);
421 if (expr == error_mark_node)
422 return error_mark_node;
424 intype = TREE_TYPE (expr);
426 gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE);
427 gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE);
429 intype = TYPE_MAIN_VARIANT (intype);
431 can_convert_intype_to_type = can_convert (type, intype, complain);
433 if (!can_convert_intype_to_type
434 && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype)
435 && ! (flags & LOOKUP_NO_CONVERSION))
437 /* Look for a user-defined conversion to lvalue that we can use. */
440 = build_type_conversion (reftype, expr);
442 if (rval_as_conversion && rval_as_conversion != error_mark_node
443 && real_lvalue_p (rval_as_conversion))
445 expr = rval_as_conversion;
446 rval_as_conversion = NULL_TREE;
448 can_convert_intype_to_type = 1;
452 if (((convtype & CONV_STATIC) && can_convert (intype, type, complain))
453 || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type))
456 tree ttl = TREE_TYPE (reftype);
457 tree ttr = lvalue_type (expr);
459 if ((complain & tf_warning)
460 && ! real_lvalue_p (expr))
461 warn_ref_binding (loc, reftype, intype, decl);
463 if (! (convtype & CONV_CONST)
464 && !at_least_as_qualified_p (ttl, ttr))
466 if (complain & tf_error)
467 permerror (loc, "conversion from %qT to %qT discards qualifiers",
470 return error_mark_node;
474 return build_up_reference (reftype, expr, flags, decl, complain);
476 else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr))
478 /* When casting an lvalue to a reference type, just convert into
479 a pointer to the new type and deference it. This is allowed
480 by San Diego WP section 5.2.9 paragraph 12, though perhaps it
481 should be done directly (jason). (int &)ri ---> *(int*)&ri */
483 /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
485 if ((complain & tf_warning)
486 && TREE_CODE (intype) == POINTER_TYPE
487 && (comptypes (TREE_TYPE (intype), type,
488 COMPARE_BASE | COMPARE_DERIVED)))
489 warning_at (loc, 0, "casting %qT to %qT does not dereference pointer",
492 rval = cp_build_addr_expr (expr, complain);
493 if (rval != error_mark_node)
494 rval = convert_force (build_pointer_type (TREE_TYPE (reftype)),
496 if (rval != error_mark_node)
497 rval = build1 (NOP_EXPR, reftype, rval);
501 rval = convert_for_initialization (NULL_TREE, type, expr, flags,
502 ICR_CONVERTING, 0, 0, complain);
503 if (rval == NULL_TREE || rval == error_mark_node)
505 if (complain & tf_warning)
506 warn_ref_binding (loc, reftype, intype, decl);
507 rval = build_up_reference (reftype, rval, flags, decl, complain);
512 /* If we found a way to convert earlier, then use it. */
516 if (complain & tf_error)
517 error_at (loc, "cannot convert type %qT to type %qT", intype, reftype);
519 return error_mark_node;
522 /* We are using a reference VAL for its value. Bash that reference all the
523 way down to its lowest form. */
526 convert_from_reference (tree val)
529 && TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE)
531 tree t = TREE_TYPE (TREE_TYPE (val));
532 tree ref = build1 (INDIRECT_REF, t, val);
535 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
536 so that we get the proper error message if the result is used
537 to assign to. Also, &* is supposed to be a no-op. */
538 TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
539 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
540 TREE_SIDE_EFFECTS (ref)
541 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val));
548 /* Really perform an lvalue-to-rvalue conversion, including copying an
549 argument of class type into a temporary. */
552 force_rvalue (tree expr, tsubst_flags_t complain)
554 tree type = TREE_TYPE (expr);
555 if (MAYBE_CLASS_TYPE_P (type) && TREE_CODE (expr) != TARGET_EXPR)
557 vec<tree, va_gc> *args = make_tree_vector_single (expr);
558 expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
559 &args, type, LOOKUP_NORMAL, complain);
560 release_tree_vector (args);
561 expr = build_cplus_new (type, expr, complain);
564 expr = decay_conversion (expr, complain);
570 /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has
571 TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR
575 ignore_overflows (tree expr, tree orig)
577 if (TREE_CODE (expr) == INTEGER_CST
578 && TREE_CODE (orig) == INTEGER_CST
579 && TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig))
581 gcc_assert (!TREE_OVERFLOW (orig));
582 /* Ensure constant sharing. */
583 expr = build_int_cst_wide (TREE_TYPE (expr),
584 TREE_INT_CST_LOW (expr),
585 TREE_INT_CST_HIGH (expr));
590 /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
594 cp_fold_convert (tree type, tree expr)
596 tree conv = fold_convert (type, expr);
597 conv = ignore_overflows (conv, expr);
601 /* C++ conversions, preference to static cast conversions. */
604 cp_convert (tree type, tree expr, tsubst_flags_t complain)
606 return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL, complain);
609 /* C++ equivalent of convert_and_check but using cp_convert as the
612 Convert EXPR to TYPE, warning about conversion problems with constants.
613 Invoke this function on every expression that is converted implicitly,
614 i.e. because of language rules and not because of an explicit cast. */
617 cp_convert_and_check (tree type, tree expr, tsubst_flags_t complain)
621 if (TREE_TYPE (expr) == type)
624 if (TREE_CODE (expr) == SIZEOF_EXPR)
625 expr = maybe_constant_value (expr);
627 result = cp_convert (type, expr, complain);
629 if ((complain & tf_warning)
630 && c_inhibit_evaluation_warnings == 0
631 && !TREE_OVERFLOW_P (expr)
632 && result != error_mark_node)
633 warnings_for_convert_and_check (type, expr, result);
640 FLAGS indicates how we should behave. */
643 ocp_convert (tree type, tree expr, int convtype, int flags,
644 tsubst_flags_t complain)
647 enum tree_code code = TREE_CODE (type);
648 const char *invalid_conv_diag;
650 location_t loc = EXPR_LOC_OR_HERE (expr);
652 if (error_operand_p (e) || type == error_mark_node)
653 return error_mark_node;
655 complete_type (type);
656 complete_type (TREE_TYPE (expr));
658 if ((invalid_conv_diag
659 = targetm.invalid_conversion (TREE_TYPE (expr), type)))
661 if (complain & tf_error)
662 error (invalid_conv_diag);
663 return error_mark_node;
666 /* FIXME remove when moving to c_fully_fold model. */
667 /* FIXME do we still need this test? */
668 if (!CLASS_TYPE_P (type))
669 e = integral_constant_value (e);
670 if (error_operand_p (e))
671 return error_mark_node;
673 if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP))
674 /* We need a new temporary; don't take this shortcut. */;
675 else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e)))
677 if (same_type_p (type, TREE_TYPE (e)))
678 /* The call to fold will not always remove the NOP_EXPR as
679 might be expected, since if one of the types is a typedef;
680 the comparison in fold is just equality of pointers, not a
681 call to comptypes. We don't call fold in this case because
682 that can result in infinite recursion; fold will call
683 convert, which will call ocp_convert, etc. */
685 /* For complex data types, we need to perform componentwise
687 else if (TREE_CODE (type) == COMPLEX_TYPE)
688 return fold_if_not_in_template (convert_to_complex (type, e));
689 else if (TREE_CODE (type) == VECTOR_TYPE)
690 return fold_if_not_in_template (convert_to_vector (type, e));
691 else if (TREE_CODE (e) == TARGET_EXPR)
693 /* Don't build a NOP_EXPR of class type. Instead, change the
694 type of the temporary. */
695 TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type;
700 /* We shouldn't be treating objects of ADDRESSABLE type as
702 gcc_assert (!TREE_ADDRESSABLE (type));
703 return fold_if_not_in_template (build_nop (type, e));
707 e1 = targetm.convert_to_type (type, e);
711 if (code == VOID_TYPE && (convtype & CONV_STATIC))
713 e = convert_to_void (e, ICV_CAST, complain);
717 if (INTEGRAL_CODE_P (code))
719 tree intype = TREE_TYPE (e);
722 if (TREE_CODE (type) == ENUMERAL_TYPE)
724 /* enum = enum, enum = int, enum = float, (enum)pointer are all
726 if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype)
727 || TREE_CODE (intype) == REAL_TYPE)
728 && ! (convtype & CONV_STATIC))
729 || TREE_CODE (intype) == POINTER_TYPE)
731 if (complain & tf_error)
732 permerror (loc, "conversion from %q#T to %q#T", intype, type);
734 return error_mark_node;
737 /* [expr.static.cast]
739 8. A value of integral or enumeration type can be explicitly
740 converted to an enumeration type. The value is unchanged if
741 the original value is within the range of the enumeration
742 values. Otherwise, the resulting enumeration value is
744 if ((complain & tf_warning)
745 && TREE_CODE (e) == INTEGER_CST
746 && !int_fits_type_p (e, ENUM_UNDERLYING_TYPE (type)))
747 warning_at (loc, OPT_Wconversion,
748 "the result of the conversion is unspecified because "
749 "%qE is outside the range of type %qT",
752 if (MAYBE_CLASS_TYPE_P (intype))
755 rval = build_type_conversion (type, e);
758 if (complain & tf_error)
759 error_at (loc, "%q#T used where a %qT was expected", intype, type);
760 return error_mark_node;
762 if (code == BOOLEAN_TYPE)
764 if (TREE_CODE (intype) == VOID_TYPE)
766 if (complain & tf_error)
768 "could not convert %qE from %<void%> to %<bool%>",
770 return error_mark_node;
773 /* We can't implicitly convert a scoped enum to bool, so convert
774 to the underlying type first. */
775 if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC))
776 e = build_nop (ENUM_UNDERLYING_TYPE (intype), e);
777 return cp_truthvalue_conversion (e);
780 converted = fold_if_not_in_template (convert_to_integer (type, e));
782 /* Ignore any integer overflow caused by the conversion. */
783 return ignore_overflows (converted, e);
785 if (NULLPTR_TYPE_P (type) && e && null_ptr_cst_p (e))
787 if (complain & tf_warning)
788 maybe_warn_zero_as_null_pointer_constant (e, loc);
791 if (POINTER_TYPE_P (type) || TYPE_PTRMEM_P (type))
792 return fold_if_not_in_template (cp_convert_to_pointer (type, e, complain));
793 if (code == VECTOR_TYPE)
795 tree in_vtype = TREE_TYPE (e);
796 if (MAYBE_CLASS_TYPE_P (in_vtype))
799 ret_val = build_type_conversion (type, e);
802 if (complain & tf_error)
803 error_at (loc, "%q#T used where a %qT was expected",
805 return error_mark_node;
807 return fold_if_not_in_template (convert_to_vector (type, e));
809 if (code == REAL_TYPE || code == COMPLEX_TYPE)
811 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e)))
814 rval = build_type_conversion (type, e);
817 else if (complain & tf_error)
819 "%q#T used where a floating point value was expected",
822 if (code == REAL_TYPE)
823 return fold_if_not_in_template (convert_to_real (type, e));
824 else if (code == COMPLEX_TYPE)
825 return fold_if_not_in_template (convert_to_complex (type, e));
828 /* New C++ semantics: since assignment is now based on
829 memberwise copying, if the rhs type is derived from the
830 lhs type, then we may still do a conversion. */
831 if (RECORD_OR_UNION_CODE_P (code))
833 tree dtype = TREE_TYPE (e);
834 tree ctor = NULL_TREE;
836 dtype = TYPE_MAIN_VARIANT (dtype);
838 /* Conversion between aggregate types. New C++ semantics allow
839 objects of derived type to be cast to objects of base type.
840 Old semantics only allowed this between pointers.
842 There may be some ambiguity between using a constructor
843 vs. using a type conversion operator when both apply. */
847 if (abstract_virtuals_error_sfinae (NULL_TREE, type, complain))
848 return error_mark_node;
850 if (BRACE_ENCLOSED_INITIALIZER_P (ctor))
851 ctor = perform_implicit_conversion (type, ctor, complain);
852 else if ((flags & LOOKUP_ONLYCONVERTING)
853 && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype)))
854 /* For copy-initialization, first we create a temp of the proper type
855 with a user-defined conversion sequence, then we direct-initialize
856 the target with the temp (see [dcl.init]). */
857 ctor = build_user_type_conversion (type, ctor, flags, complain);
860 vec<tree, va_gc> *ctor_vec = make_tree_vector_single (ctor);
861 ctor = build_special_member_call (NULL_TREE,
862 complete_ctor_identifier,
864 type, flags, complain);
865 release_tree_vector (ctor_vec);
868 return build_cplus_new (type, ctor, complain);
871 if (complain & tf_error)
873 /* If the conversion failed and expr was an invalid use of pointer to
874 member function, try to report a meaningful error. */
875 if (invalid_nonstatic_memfn_p (expr, complain))
876 /* We displayed the error message. */;
878 error_at (loc, "conversion from %qT to non-scalar type %qT requested",
879 TREE_TYPE (expr), type);
881 return error_mark_node;
884 /* When an expression is used in a void context, its value is discarded and
885 no lvalue-rvalue and similar conversions happen [expr.static.cast/4,
886 stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type
887 in a void context. The C++ standard does not define what an `access' to an
888 object is, but there is reason to believe that it is the lvalue to rvalue
889 conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it
890 accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8
891 indicates that volatile semantics should be the same between C and C++
892 where ever possible. C leaves it implementation defined as to what
893 constitutes an access to a volatile. So, we interpret `*vp' as a read of
894 the volatile object `vp' points to, unless that is an incomplete type. For
895 volatile references we do not do this interpretation, because that would
896 make it impossible to ignore the reference return value from functions. We
897 issue warnings in the confusing cases.
899 The IMPLICIT is ICV_CAST when the user is explicitly converting an expression
900 to void via a cast. If an expression is being implicitly converted, IMPLICIT
901 indicates the context of the implicit conversion. */
904 convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
906 location_t loc = EXPR_LOC_OR_HERE (expr);
908 if (expr == error_mark_node
909 || TREE_TYPE (expr) == error_mark_node)
910 return error_mark_node;
912 if (implicit == ICV_CAST)
913 mark_exp_read (expr);
918 while (TREE_CODE (exprv) == COMPOUND_EXPR)
919 exprv = TREE_OPERAND (exprv, 1);
921 || handled_component_p (exprv)
922 || TREE_CODE (exprv) == INDIRECT_REF)
923 /* Expr is not being 'used' here, otherwise we whould have
924 called mark_{rl}value_use use here, which would have in turn
925 called mark_exp_read. Rather, we call mark_exp_read directly
926 to avoid some warnings when
927 -Wunused-but-set-{variable,parameter} is in effect. */
928 mark_exp_read (exprv);
931 if (!TREE_TYPE (expr))
933 if (invalid_nonstatic_memfn_p (expr, complain))
934 return error_mark_node;
935 if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
937 if (complain & tf_error)
938 error_at (loc, "pseudo-destructor is not called");
939 return error_mark_node;
941 if (VOID_TYPE_P (TREE_TYPE (expr)))
943 switch (TREE_CODE (expr))
947 /* The two parts of a cond expr might be separate lvalues. */
948 tree op1 = TREE_OPERAND (expr,1);
949 tree op2 = TREE_OPERAND (expr,2);
950 bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1))
951 || TREE_SIDE_EFFECTS (op2));
952 tree new_op1, new_op2;
954 if (implicit != ICV_CAST && !side_effects)
957 new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
958 new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
963 new_op1 = convert_to_void (op1, ICV_CAST, complain);
964 new_op2 = convert_to_void (op2, ICV_CAST, complain);
967 expr = build3 (COND_EXPR, TREE_TYPE (new_op2),
968 TREE_OPERAND (expr, 0), new_op1, new_op2);
974 /* The second part of a compound expr contains the value. */
975 tree op1 = TREE_OPERAND (expr,1);
977 if (implicit != ICV_CAST && !TREE_NO_WARNING (expr))
978 new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
980 new_op1 = convert_to_void (op1, ICV_CAST, complain);
984 tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
985 TREE_OPERAND (expr, 0), new_op1);
992 case NON_LVALUE_EXPR:
994 /* These have already decayed to rvalue. */
997 case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
1002 tree type = TREE_TYPE (expr);
1003 int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
1005 int is_volatile = TYPE_VOLATILE (type);
1006 int is_complete = COMPLETE_TYPE_P (complete_type (type));
1008 /* Can't load the value if we don't know the type. */
1009 if (is_volatile && !is_complete)
1011 if (complain & tf_warning)
1015 warning_at (loc, 0, "conversion to void will not access "
1016 "object of incomplete type %qT", type);
1018 case ICV_SECOND_OF_COND:
1019 warning_at (loc, 0, "indirection will not access object of "
1020 "incomplete type %qT in second operand "
1021 "of conditional expression", type);
1023 case ICV_THIRD_OF_COND:
1024 warning_at (loc, 0, "indirection will not access object of "
1025 "incomplete type %qT in third operand "
1026 "of conditional expression", type);
1028 case ICV_RIGHT_OF_COMMA:
1029 warning_at (loc, 0, "indirection will not access object of "
1030 "incomplete type %qT in right operand of "
1031 "comma operator", type);
1033 case ICV_LEFT_OF_COMMA:
1034 warning_at (loc, 0, "indirection will not access object of "
1035 "incomplete type %qT in left operand of "
1036 "comma operator", type);
1039 warning_at (loc, 0, "indirection will not access object of "
1040 "incomplete type %qT in statement", type);
1042 case ICV_THIRD_IN_FOR:
1043 warning_at (loc, 0, "indirection will not access object of "
1044 "incomplete type %qT in for increment "
1045 "expression", type);
1051 /* Don't load the value if this is an implicit dereference, or if
1052 the type needs to be handled by ctors/dtors. */
1053 else if (is_volatile && is_reference)
1055 if (complain & tf_warning)
1059 warning_at (loc, 0, "conversion to void will not access "
1060 "object of type %qT", type);
1062 case ICV_SECOND_OF_COND:
1063 warning_at (loc, 0, "implicit dereference will not access "
1064 "object of type %qT in second operand of "
1065 "conditional expression", type);
1067 case ICV_THIRD_OF_COND:
1068 warning_at (loc, 0, "implicit dereference will not access "
1069 "object of type %qT in third operand of "
1070 "conditional expression", type);
1072 case ICV_RIGHT_OF_COMMA:
1073 warning_at (loc, 0, "implicit dereference will not access "
1074 "object of type %qT in right operand of "
1075 "comma operator", type);
1077 case ICV_LEFT_OF_COMMA:
1078 warning_at (loc, 0, "implicit dereference will not access "
1079 "object of type %qT in left operand of comma "
1083 warning_at (loc, 0, "implicit dereference will not access "
1084 "object of type %qT in statement", type);
1086 case ICV_THIRD_IN_FOR:
1087 warning_at (loc, 0, "implicit dereference will not access "
1088 "object of type %qT in for increment expression",
1095 else if (is_volatile && TREE_ADDRESSABLE (type))
1097 if (complain & tf_warning)
1101 warning_at (loc, 0, "conversion to void will not access "
1102 "object of non-trivially-copyable type %qT",
1105 case ICV_SECOND_OF_COND:
1106 warning_at (loc, 0, "indirection will not access object of "
1107 "non-trivially-copyable type %qT in second "
1108 "operand of conditional expression", type);
1110 case ICV_THIRD_OF_COND:
1111 warning_at (loc, 0, "indirection will not access object of "
1112 "non-trivially-copyable type %qT in third "
1113 "operand of conditional expression", type);
1115 case ICV_RIGHT_OF_COMMA:
1116 warning_at (loc, 0, "indirection will not access object of "
1117 "non-trivially-copyable type %qT in right "
1118 "operand of comma operator", type);
1120 case ICV_LEFT_OF_COMMA:
1121 warning_at (loc, 0, "indirection will not access object of "
1122 "non-trivially-copyable type %qT in left "
1123 "operand of comma operator", type);
1126 warning_at (loc, 0, "indirection will not access object of "
1127 "non-trivially-copyable type %qT in statement",
1130 case ICV_THIRD_IN_FOR:
1131 warning_at (loc, 0, "indirection will not access object of "
1132 "non-trivially-copyable type %qT in for "
1133 "increment expression", type);
1139 if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
1141 /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
1142 operation is stripped off. Note that we don't warn about
1143 - an expression with TREE_NO_WARNING set. (For an example of
1144 such expressions, see build_over_call in call.c.)
1145 - automatic dereferencing of references, since the user cannot
1146 control it. (See also warn_if_unused_value() in c-common.c.) */
1147 if (warn_unused_value
1148 && implicit != ICV_CAST
1149 && (complain & tf_warning)
1150 && !TREE_NO_WARNING (expr)
1152 warning_at (loc, OPT_Wunused_value, "value computed is not used");
1153 expr = TREE_OPERAND (expr, 0);
1161 /* External variables might be incomplete. */
1162 tree type = TREE_TYPE (expr);
1163 int is_complete = COMPLETE_TYPE_P (complete_type (type));
1165 if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
1169 warning_at (loc, 0, "conversion to void will not access "
1170 "object %qE of incomplete type %qT", expr, type);
1172 case ICV_SECOND_OF_COND:
1173 warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1174 "not be accessed in second operand of "
1175 "conditional expression", expr, type);
1177 case ICV_THIRD_OF_COND:
1178 warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1179 "not be accessed in third operand of "
1180 "conditional expression", expr, type);
1182 case ICV_RIGHT_OF_COMMA:
1183 warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1184 "not be accessed in right operand of comma operator",
1187 case ICV_LEFT_OF_COMMA:
1188 warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1189 "not be accessed in left operand of comma operator",
1193 warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1194 "not be accessed in statement", expr, type);
1196 case ICV_THIRD_IN_FOR:
1197 warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1198 "not be accessed in for increment expression",
1209 /* Don't bother with the temporary object returned from a function if
1210 we don't use it and don't need to destroy it. We'll still
1211 allocate space for it in expand_call or declare_return_variable,
1212 but we don't need to track it through all the tree phases. */
1213 if (TARGET_EXPR_IMPLICIT_P (expr)
1214 && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
1216 tree init = TARGET_EXPR_INITIAL (expr);
1217 if (TREE_CODE (init) == AGGR_INIT_EXPR
1218 && !AGGR_INIT_VIA_CTOR_P (init))
1220 tree fn = AGGR_INIT_EXPR_FN (init);
1221 expr = build_call_array_loc (input_location,
1222 TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
1224 aggr_init_expr_nargs (init),
1225 AGGR_INIT_EXPR_ARGP (init));
1232 expr = resolve_nondeduced_context (expr);
1236 if (TREE_CODE (probe) == ADDR_EXPR)
1237 probe = TREE_OPERAND (expr, 0);
1238 if (type_unknown_p (probe))
1240 /* [over.over] enumerates the places where we can take the address
1241 of an overloaded function, and this is not one of them. */
1242 if (complain & tf_error)
1246 error_at (loc, "conversion to void "
1247 "cannot resolve address of overloaded function");
1249 case ICV_SECOND_OF_COND:
1250 error_at (loc, "second operand of conditional expression "
1251 "cannot resolve address of overloaded function");
1253 case ICV_THIRD_OF_COND:
1254 error_at (loc, "third operand of conditional expression "
1255 "cannot resolve address of overloaded function");
1257 case ICV_RIGHT_OF_COMMA:
1258 error_at (loc, "right operand of comma operator "
1259 "cannot resolve address of overloaded function");
1261 case ICV_LEFT_OF_COMMA:
1262 error_at (loc, "left operand of comma operator "
1263 "cannot resolve address of overloaded function");
1266 error_at (loc, "statement "
1267 "cannot resolve address of overloaded function");
1269 case ICV_THIRD_IN_FOR:
1270 error_at (loc, "for increment expression "
1271 "cannot resolve address of overloaded function");
1275 return error_mark_node;
1276 expr = void_zero_node;
1278 else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
1280 /* Only warn when there is no &. */
1281 if (complain & tf_warning)
1284 case ICV_SECOND_OF_COND:
1285 warning_at (loc, OPT_Waddress,
1286 "second operand of conditional expression "
1287 "is a reference, not call, to function %qE", expr);
1289 case ICV_THIRD_OF_COND:
1290 warning_at (loc, OPT_Waddress,
1291 "third operand of conditional expression "
1292 "is a reference, not call, to function %qE", expr);
1294 case ICV_RIGHT_OF_COMMA:
1295 warning_at (loc, OPT_Waddress,
1296 "right operand of comma operator "
1297 "is a reference, not call, to function %qE", expr);
1299 case ICV_LEFT_OF_COMMA:
1300 warning_at (loc, OPT_Waddress,
1301 "left operand of comma operator "
1302 "is a reference, not call, to function %qE", expr);
1305 warning_at (loc, OPT_Waddress,
1306 "statement is a reference, not call, to function %qE",
1309 case ICV_THIRD_IN_FOR:
1310 warning_at (loc, OPT_Waddress,
1311 "for increment expression "
1312 "is a reference, not call, to function %qE", expr);
1318 if (TREE_CODE (expr) == COMPONENT_REF)
1319 expr = TREE_OPERAND (expr, 0);
1323 if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
1325 if (implicit != ICV_CAST
1326 && warn_unused_value
1327 && !TREE_NO_WARNING (expr)
1328 && !processing_template_decl)
1330 /* The middle end does not warn about expressions that have
1331 been explicitly cast to void, so we must do so here. */
1332 if (!TREE_SIDE_EFFECTS (expr)) {
1333 if (complain & tf_warning)
1336 case ICV_SECOND_OF_COND:
1337 warning_at (loc, OPT_Wunused_value,
1338 "second operand of conditional expression "
1341 case ICV_THIRD_OF_COND:
1342 warning_at (loc, OPT_Wunused_value,
1343 "third operand of conditional expression "
1346 case ICV_RIGHT_OF_COMMA:
1347 warning_at (loc, OPT_Wunused_value,
1348 "right operand of comma operator has no effect");
1350 case ICV_LEFT_OF_COMMA:
1351 warning_at (loc, OPT_Wunused_value,
1352 "left operand of comma operator has no effect");
1355 warning_at (loc, OPT_Wunused_value,
1356 "statement has no effect");
1358 case ICV_THIRD_IN_FOR:
1359 warning_at (loc, OPT_Wunused_value,
1360 "for increment expression has no effect");
1369 enum tree_code code;
1370 enum tree_code_class tclass;
1373 /* We might like to warn about (say) "(int) f()", as the
1374 cast has no effect, but the compiler itself will
1375 generate implicit conversions under some
1376 circumstances. (For example a block copy will be
1377 turned into a call to "__builtin_memcpy", with a
1378 conversion of the return value to an appropriate
1379 type.) So, to avoid false positives, we strip
1380 conversions. Do not use STRIP_NOPs because it will
1381 not strip conversions to "void", as that is not a
1382 mode-preserving conversion. */
1383 while (TREE_CODE (e) == NOP_EXPR)
1384 e = TREE_OPERAND (e, 0);
1386 code = TREE_CODE (e);
1387 tclass = TREE_CODE_CLASS (code);
1388 if ((tclass == tcc_comparison
1389 || tclass == tcc_unary
1390 || (tclass == tcc_binary
1391 && !(code == MODIFY_EXPR
1392 || code == INIT_EXPR
1393 || code == PREDECREMENT_EXPR
1394 || code == PREINCREMENT_EXPR
1395 || code == POSTDECREMENT_EXPR
1396 || code == POSTINCREMENT_EXPR)))
1397 && (complain & tf_warning))
1398 warning_at (loc, OPT_Wunused_value, "value computed is not used");
1401 expr = build1 (CONVERT_EXPR, void_type_node, expr);
1403 if (! TREE_SIDE_EFFECTS (expr))
1404 expr = void_zero_node;
1408 /* Create an expression whose value is that of EXPR,
1409 converted to type TYPE. The TREE_TYPE of the value
1410 is always TYPE. This function implements all reasonable
1411 conversions; callers should filter out those that are
1412 not permitted by the language being compiled.
1414 Most of this routine is from build_reinterpret_cast.
1416 The back end cannot call cp_convert (what was convert) because
1417 conversions to/from basetypes may involve memory references
1418 (vbases) and adding or subtracting small values (multiple
1419 inheritance), but it calls convert from the constant folding code
1420 on subtrees of already built trees after it has ripped them apart.
1422 Also, if we ever support range variables, we'll probably also have to
1423 do a little bit more work. */
1426 convert (tree type, tree expr)
1430 if (type == error_mark_node || expr == error_mark_node)
1431 return error_mark_node;
1433 intype = TREE_TYPE (expr);
1435 if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype))
1436 return fold_if_not_in_template (build_nop (type, expr));
1438 return ocp_convert (type, expr, CONV_OLD_CONVERT,
1439 LOOKUP_NORMAL|LOOKUP_NO_CONVERSION,
1440 tf_warning_or_error);
1443 /* Like cp_convert, except permit conversions to take place which
1444 are not normally allowed due to access restrictions
1445 (such as conversion from sub-type to private super-type). */
1448 convert_force (tree type, tree expr, int convtype, tsubst_flags_t complain)
1451 enum tree_code code = TREE_CODE (type);
1453 if (code == REFERENCE_TYPE)
1454 return (fold_if_not_in_template
1455 (convert_to_reference (type, e, CONV_C_CAST, 0,
1456 NULL_TREE, complain)));
1458 if (code == POINTER_TYPE)
1459 return fold_if_not_in_template (convert_to_pointer_force (type, e,
1462 /* From typeck.c convert_for_assignment */
1463 if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR
1464 && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE
1465 && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE)
1466 || integer_zerop (e)
1467 || TYPE_PTRMEMFUNC_P (TREE_TYPE (e)))
1468 && TYPE_PTRMEMFUNC_P (type))
1469 /* compatible pointer to member functions. */
1470 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1,
1471 /*c_cast_p=*/1, complain);
1473 return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL, complain);
1476 /* Convert an aggregate EXPR to type XTYPE. If a conversion
1477 exists, return the attempted conversion. This may
1478 return ERROR_MARK_NODE if the conversion is not
1479 allowed (references private members, etc).
1480 If no conversion exists, NULL_TREE is returned.
1482 FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1483 object parameter, or by the second standard conversion sequence if
1484 that doesn't do it. This will probably wait for an overloading rewrite.
1488 build_type_conversion (tree xtype, tree expr)
1490 /* C++: check to see if we can convert this aggregate type
1491 into the required type. */
1492 return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL,
1493 tf_warning_or_error);
1496 /* Convert the given EXPR to one of a group of types suitable for use in an
1497 expression. DESIRES is a combination of various WANT_* flags (q.v.)
1498 which indicates which types are suitable. If COMPLAIN is true, complain
1499 about ambiguity; otherwise, the caller will deal with it. */
1502 build_expr_type_conversion (int desires, tree expr, bool complain)
1504 tree basetype = TREE_TYPE (expr);
1505 tree conv = NULL_TREE;
1506 tree winner = NULL_TREE;
1508 if (expr == null_node
1509 && (desires & WANT_INT)
1510 && !(desires & WANT_NULL))
1512 source_location loc =
1513 expansion_point_location_if_in_system_header (input_location);
1515 warning_at (loc, OPT_Wconversion_null,
1516 "converting NULL to non-pointer type");
1519 if (basetype == error_mark_node)
1520 return error_mark_node;
1522 if (! MAYBE_CLASS_TYPE_P (basetype))
1523 switch (TREE_CODE (basetype))
1526 if ((desires & WANT_NULL) && null_ptr_cst_p (expr))
1528 /* else fall through... */
1531 return (desires & WANT_INT) ? expr : NULL_TREE;
1533 return (desires & WANT_ENUM) ? expr : NULL_TREE;
1535 return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1537 return (desires & WANT_POINTER) ? expr : NULL_TREE;
1541 return (desires & WANT_POINTER) ? decay_conversion (expr,
1542 tf_warning_or_error)
1547 if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1549 switch (TREE_CODE (TREE_TYPE (basetype)))
1553 return (desires & WANT_INT) ? expr : NULL_TREE;
1555 return (desires & WANT_ENUM) ? expr : NULL_TREE;
1557 return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1566 /* The code for conversions from class type is currently only used for
1567 delete expressions. Other expressions are handled by build_new_op. */
1568 if (!complete_type_or_maybe_complain (basetype, expr, complain))
1569 return error_mark_node;
1570 if (!TYPE_HAS_CONVERSION (basetype))
1573 for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv))
1577 tree cand = TREE_VALUE (conv);
1578 cand = OVL_CURRENT (cand);
1580 if (winner && winner == cand)
1583 if (DECL_NONCONVERTING_P (cand))
1586 candidate = non_reference (TREE_TYPE (TREE_TYPE (cand)));
1588 switch (TREE_CODE (candidate))
1592 win = (desires & WANT_INT); break;
1594 win = (desires & WANT_ENUM); break;
1596 win = (desires & WANT_FLOAT); break;
1598 win = (desires & WANT_POINTER); break;
1602 if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1604 switch (TREE_CODE (TREE_TYPE (candidate)))
1608 win = (desires & WANT_INT); break;
1610 win = (desires & WANT_ENUM); break;
1612 win = (desires & WANT_FLOAT); break;
1619 /* A wildcard could be instantiated to match any desired
1620 type, but we can't deduce the template argument. */
1621 if (WILDCARD_TYPE_P (candidate))
1628 if (TREE_CODE (cand) == TEMPLATE_DECL)
1631 error ("default type conversion can't deduce template"
1632 " argument for %qD", cand);
1633 return error_mark_node;
1640 error ("ambiguous default type conversion from %qT",
1642 error (" candidate conversions include %qD and %qD",
1645 return error_mark_node;
1654 tree type = non_reference (TREE_TYPE (TREE_TYPE (winner)));
1655 return build_user_type_conversion (type, expr, LOOKUP_NORMAL,
1656 tf_warning_or_error);
1662 /* Implements integral promotion (4.1) and float->double promotion. */
1665 type_promotes_to (tree type)
1669 if (type == error_mark_node)
1670 return error_mark_node;
1672 type = TYPE_MAIN_VARIANT (type);
1674 /* Check for promotions of target-defined types first. */
1675 promoted_type = targetm.promoted_type (type);
1677 return promoted_type;
1679 /* bool always promotes to int (not unsigned), even if it's the same
1681 if (TREE_CODE (type) == BOOLEAN_TYPE)
1682 type = integer_type_node;
1684 /* Scoped enums don't promote, but pretend they do for backward ABI bug
1685 compatibility wrt varargs. */
1686 else if (SCOPED_ENUM_P (type) && abi_version_at_least (6))
1689 /* Normally convert enums to int, but convert wide enums to something
1691 else if (TREE_CODE (type) == ENUMERAL_TYPE
1692 || type == char16_type_node
1693 || type == char32_type_node
1694 || type == wchar_type_node)
1696 int precision = MAX (TYPE_PRECISION (type),
1697 TYPE_PRECISION (integer_type_node));
1698 tree totype = c_common_type_for_size (precision, 0);
1699 if (SCOPED_ENUM_P (type))
1700 warning (OPT_Wabi, "scoped enum %qT will not promote to an integral "
1701 "type in a future version of GCC", type);
1702 if (TREE_CODE (type) == ENUMERAL_TYPE)
1703 type = ENUM_UNDERLYING_TYPE (type);
1704 if (TYPE_UNSIGNED (type)
1705 && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype))
1706 type = c_common_type_for_size (precision, 1);
1710 else if (c_promoting_integer_type_p (type))
1712 /* Retain unsignedness if really not getting bigger. */
1713 if (TYPE_UNSIGNED (type)
1714 && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
1715 type = unsigned_type_node;
1717 type = integer_type_node;
1719 else if (type == float_type_node)
1720 type = double_type_node;
1725 /* The routines below this point are carefully written to conform to
1726 the standard. They use the same terminology, and follow the rules
1727 closely. Although they are used only in pt.c at the moment, they
1728 should presumably be used everywhere in the future. */
1730 /* Attempt to perform qualification conversions on EXPR to convert it
1731 to TYPE. Return the resulting expression, or error_mark_node if
1732 the conversion was impossible. */
1735 perform_qualification_conversions (tree type, tree expr)
1739 expr_type = TREE_TYPE (expr);
1741 if (same_type_p (type, expr_type))
1743 else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type)
1744 && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type)))
1745 return build_nop (type, expr);
1746 else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (expr_type)
1747 && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type),
1748 TYPE_PTRMEM_CLASS_TYPE (expr_type))
1749 && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type),
1750 TYPE_PTRMEM_POINTED_TO_TYPE (expr_type)))
1751 return build_nop (type, expr);
1753 return error_mark_node;