1 /* Language-level data type conversion for GNU C++.
2 Copyright (C) 1987-2015 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"
33 #include "stor-layout.h"
41 static tree
cp_convert_to_pointer (tree
, tree
, tsubst_flags_t
);
42 static tree
convert_to_pointer_force (tree
, tree
, tsubst_flags_t
);
43 static tree
build_type_conversion (tree
, tree
);
44 static tree
build_up_reference (tree
, tree
, int, tree
, tsubst_flags_t
);
45 static void diagnose_ref_binding (location_t
, 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
, tsubst_flags_t complain
)
79 tree intype
= TREE_TYPE (expr
);
82 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
84 if (intype
== error_mark_node
)
85 return error_mark_node
;
87 if (MAYBE_CLASS_TYPE_P (intype
))
89 intype
= complete_type (intype
);
90 if (!COMPLETE_TYPE_P (intype
))
92 if (complain
& tf_error
)
93 error_at (loc
, "can%'t convert from incomplete type %qT to %qT",
95 return error_mark_node
;
98 rval
= build_type_conversion (type
, expr
);
101 if ((complain
& tf_error
)
102 && rval
== error_mark_node
)
103 error_at (loc
, "conversion of %qE from %qT to %qT is ambiguous",
109 /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
110 if (TYPE_PTR_P (type
)
111 && (TREE_CODE (TREE_TYPE (type
)) == FUNCTION_TYPE
112 || VOID_TYPE_P (TREE_TYPE (type
))))
114 if (TYPE_PTRMEMFUNC_P (intype
)
115 || TREE_CODE (intype
) == METHOD_TYPE
)
116 return convert_member_func_to_ptr (type
, expr
, complain
);
117 if (TYPE_PTR_P (TREE_TYPE (expr
)))
118 return build_nop (type
, expr
);
119 intype
= TREE_TYPE (expr
);
122 if (expr
== error_mark_node
)
123 return error_mark_node
;
125 form
= TREE_CODE (intype
);
127 if (POINTER_TYPE_P (intype
))
129 intype
= TYPE_MAIN_VARIANT (intype
);
131 if (TYPE_MAIN_VARIANT (type
) != intype
133 && TREE_CODE (TREE_TYPE (type
)) == RECORD_TYPE
134 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type
))
135 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype
))
136 && TREE_CODE (TREE_TYPE (intype
)) == RECORD_TYPE
)
138 enum tree_code code
= PLUS_EXPR
;
144 intype_class
= TREE_TYPE (intype
);
145 type_class
= TREE_TYPE (type
);
147 same_p
= same_type_p (TYPE_MAIN_VARIANT (intype_class
),
148 TYPE_MAIN_VARIANT (type_class
));
150 /* Try derived to base conversion. */
152 binfo
= lookup_base (intype_class
, type_class
, ba_check
,
154 if (!same_p
&& !binfo
)
156 /* Try base to derived conversion. */
157 binfo
= lookup_base (type_class
, intype_class
, ba_check
,
161 if (binfo
== error_mark_node
)
162 return error_mark_node
;
166 expr
= build_base_path (code
, expr
, binfo
, 0, complain
);
167 /* Add any qualifier conversions. */
168 return build_nop (type
, expr
);
172 if (TYPE_PTRMEMFUNC_P (type
))
174 if (complain
& tf_error
)
175 error_at (loc
, "cannot convert %qE from type %qT to type %qT",
177 return error_mark_node
;
180 return build_nop (type
, expr
);
182 else if ((TYPE_PTRDATAMEM_P (type
) && TYPE_PTRDATAMEM_P (intype
))
183 || (TYPE_PTRMEMFUNC_P (type
) && TYPE_PTRMEMFUNC_P (intype
)))
184 return convert_ptrmem (type
, expr
, /*allow_inverse_p=*/false,
185 /*c_cast_p=*/false, complain
);
186 else if (TYPE_PTRMEMFUNC_P (intype
))
190 if (TREE_CODE (expr
) == PTRMEM_CST
)
191 return cp_convert_to_pointer (type
, PTRMEM_CST_MEMBER (expr
),
193 else if (TREE_CODE (expr
) == OFFSET_REF
)
195 tree object
= TREE_OPERAND (expr
, 0);
196 return get_member_function_from_ptrfunc (&object
,
197 TREE_OPERAND (expr
, 1),
201 if (complain
& tf_error
)
202 error_at (loc
, "cannot convert %qE from type %qT to type %qT",
204 return error_mark_node
;
207 if (null_ptr_cst_p (expr
))
209 if (TYPE_PTRMEMFUNC_P (type
))
210 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type
), expr
, 0,
211 /*c_cast_p=*/false, complain
);
213 if (complain
& tf_warning
)
214 maybe_warn_zero_as_null_pointer_constant (expr
, loc
);
216 /* A NULL pointer-to-data-member is represented by -1, not by
218 tree val
= (TYPE_PTRDATAMEM_P (type
)
219 ? build_int_cst_type (type
, -1)
220 : build_int_cst (type
, 0));
222 return (TREE_SIDE_EFFECTS (expr
)
223 ? build2 (COMPOUND_EXPR
, type
, expr
, val
) : val
);
225 else if (TYPE_PTRMEM_P (type
) && INTEGRAL_CODE_P (form
))
227 if (complain
& tf_error
)
228 error_at (loc
, "invalid conversion from %qT to %qT", intype
, type
);
229 return error_mark_node
;
232 if (INTEGRAL_CODE_P (form
))
234 if (TYPE_PRECISION (intype
) == POINTER_SIZE
)
235 return build1 (CONVERT_EXPR
, type
, expr
);
236 expr
= cp_convert (c_common_type_for_size (POINTER_SIZE
, 0), expr
,
238 /* Modes may be different but sizes should be the same. There
239 is supposed to be some integral type that is the same width
241 gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr
)))
242 == GET_MODE_SIZE (TYPE_MODE (type
)));
244 return convert_to_pointer (type
, expr
);
247 if (type_unknown_p (expr
))
248 return instantiate_type (type
, expr
, complain
);
250 if (complain
& tf_error
)
251 error_at (loc
, "cannot convert %qE from type %qT to type %qT",
253 return error_mark_node
;
256 /* Like convert, except permit conversions to take place which
257 are not normally allowed due to access restrictions
258 (such as conversion from sub-type to private super-type). */
261 convert_to_pointer_force (tree type
, tree expr
, tsubst_flags_t complain
)
263 tree intype
= TREE_TYPE (expr
);
264 enum tree_code form
= TREE_CODE (intype
);
266 if (form
== POINTER_TYPE
)
268 intype
= TYPE_MAIN_VARIANT (intype
);
270 if (TYPE_MAIN_VARIANT (type
) != intype
271 && TREE_CODE (TREE_TYPE (type
)) == RECORD_TYPE
272 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type
))
273 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype
))
274 && TREE_CODE (TREE_TYPE (intype
)) == RECORD_TYPE
)
276 enum tree_code code
= PLUS_EXPR
;
279 binfo
= lookup_base (TREE_TYPE (intype
), TREE_TYPE (type
),
280 ba_unique
, NULL
, complain
);
283 binfo
= lookup_base (TREE_TYPE (type
), TREE_TYPE (intype
),
284 ba_unique
, NULL
, complain
);
287 if (binfo
== error_mark_node
)
288 return error_mark_node
;
291 expr
= build_base_path (code
, expr
, binfo
, 0, complain
);
292 if (expr
== error_mark_node
)
293 return error_mark_node
;
294 /* Add any qualifier conversions. */
295 if (!same_type_p (TREE_TYPE (TREE_TYPE (expr
)),
297 expr
= build_nop (type
, expr
);
303 return cp_convert_to_pointer (type
, expr
, complain
);
306 /* We are passing something to a function which requires a reference.
307 The type we are interested in is in TYPE. The initial
308 value we have to begin with is in ARG.
310 FLAGS controls how we manage access checking.
311 DIRECT_BIND in FLAGS controls how any temporaries are generated.
312 If DIRECT_BIND is set, DECL is the reference we're binding to. */
315 build_up_reference (tree type
, tree arg
, int flags
, tree decl
,
316 tsubst_flags_t complain
)
319 tree argtype
= TREE_TYPE (arg
);
320 tree target_type
= TREE_TYPE (type
);
322 gcc_assert (TREE_CODE (type
) == REFERENCE_TYPE
);
324 if ((flags
& DIRECT_BIND
) && ! real_lvalue_p (arg
))
326 /* Create a new temporary variable. We can't just use a TARGET_EXPR
327 here because it needs to live as long as DECL. */
330 arg
= make_temporary_var_for_ref_to_temp (decl
, target_type
);
332 /* Process the initializer for the declaration. */
333 DECL_INITIAL (arg
) = targ
;
334 cp_finish_decl (arg
, targ
, /*init_const_expr_p=*/false, NULL_TREE
,
335 LOOKUP_ONLYCONVERTING
|DIRECT_BIND
);
337 else if (!(flags
& DIRECT_BIND
) && ! lvalue_p (arg
))
338 return get_target_expr_sfinae (arg
, complain
);
340 /* If we had a way to wrap this up, and say, if we ever needed its
341 address, transform all occurrences of the register, into a memory
342 reference we could win better. */
343 rval
= cp_build_addr_expr (arg
, complain
);
344 if (rval
== error_mark_node
)
345 return error_mark_node
;
347 if ((flags
& LOOKUP_PROTECT
)
348 && TYPE_MAIN_VARIANT (argtype
) != TYPE_MAIN_VARIANT (target_type
)
349 && MAYBE_CLASS_TYPE_P (argtype
)
350 && MAYBE_CLASS_TYPE_P (target_type
))
352 /* We go through lookup_base for the access control. */
353 tree binfo
= lookup_base (argtype
, target_type
, ba_check
,
355 if (binfo
== error_mark_node
)
356 return error_mark_node
;
357 if (binfo
== NULL_TREE
)
358 return error_not_base_type (target_type
, argtype
);
359 rval
= build_base_path (PLUS_EXPR
, rval
, binfo
, 1, complain
);
363 = convert_to_pointer_force (build_pointer_type (target_type
),
365 return build_nop (type
, rval
);
368 /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
369 INTYPE is the original rvalue type and DECL is an optional _DECL node
372 [dcl.init.ref] says that if an rvalue is used to
373 initialize a reference, then the reference must be to a
374 non-volatile const type. */
377 diagnose_ref_binding (location_t loc
, tree reftype
, tree intype
, tree decl
)
379 tree ttl
= TREE_TYPE (reftype
);
381 if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl
))
385 if (CP_TYPE_VOLATILE_P (ttl
) && decl
)
386 msg
= G_("initialization of volatile reference type %q#T from "
387 "rvalue of type %qT");
388 else if (CP_TYPE_VOLATILE_P (ttl
))
389 msg
= G_("conversion to volatile reference type %q#T "
390 "from rvalue of type %qT");
392 msg
= G_("initialization of non-const reference type %q#T from "
393 "rvalue of type %qT");
395 msg
= G_("conversion to non-const reference type %q#T from "
396 "rvalue of type %qT");
398 permerror (loc
, msg
, reftype
, intype
);
402 /* For C++: Only need to do one-level references, but cannot
403 get tripped up on signed/unsigned differences.
405 DECL is either NULL_TREE or the _DECL node for a reference that is being
406 initialized. It can be error_mark_node if we don't know the _DECL but
407 we know it's an initialization. */
410 convert_to_reference (tree reftype
, tree expr
, int convtype
,
411 int flags
, tree decl
, tsubst_flags_t complain
)
413 tree type
= TYPE_MAIN_VARIANT (TREE_TYPE (reftype
));
415 tree rval
= NULL_TREE
;
416 tree rval_as_conversion
= NULL_TREE
;
417 bool can_convert_intype_to_type
;
418 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
420 if (TREE_CODE (type
) == FUNCTION_TYPE
421 && TREE_TYPE (expr
) == unknown_type_node
)
422 expr
= instantiate_type (type
, expr
, complain
);
424 if (expr
== error_mark_node
)
425 return error_mark_node
;
427 intype
= TREE_TYPE (expr
);
429 gcc_assert (TREE_CODE (intype
) != REFERENCE_TYPE
);
430 gcc_assert (TREE_CODE (reftype
) == REFERENCE_TYPE
);
432 intype
= TYPE_MAIN_VARIANT (intype
);
434 can_convert_intype_to_type
= can_convert_standard (type
, intype
, complain
);
436 if (!can_convert_intype_to_type
437 && (convtype
& CONV_IMPLICIT
) && MAYBE_CLASS_TYPE_P (intype
)
438 && ! (flags
& LOOKUP_NO_CONVERSION
))
440 /* Look for a user-defined conversion to lvalue that we can use. */
443 = build_type_conversion (reftype
, expr
);
445 if (rval_as_conversion
&& rval_as_conversion
!= error_mark_node
446 && real_lvalue_p (rval_as_conversion
))
448 expr
= rval_as_conversion
;
449 rval_as_conversion
= NULL_TREE
;
451 can_convert_intype_to_type
= 1;
455 if (((convtype
& CONV_STATIC
)
456 && can_convert_standard (intype
, type
, complain
))
457 || ((convtype
& CONV_IMPLICIT
) && can_convert_intype_to_type
))
460 tree ttl
= TREE_TYPE (reftype
);
461 tree ttr
= lvalue_type (expr
);
463 if ((complain
& tf_error
)
464 && ! real_lvalue_p (expr
))
465 diagnose_ref_binding (loc
, reftype
, intype
, decl
);
467 if (! (convtype
& CONV_CONST
)
468 && !at_least_as_qualified_p (ttl
, ttr
))
470 if (complain
& tf_error
)
471 permerror (loc
, "conversion from %qT to %qT discards qualifiers",
474 return error_mark_node
;
478 return build_up_reference (reftype
, expr
, flags
, decl
, complain
);
480 else if ((convtype
& CONV_REINTERPRET
) && lvalue_p (expr
))
482 /* When casting an lvalue to a reference type, just convert into
483 a pointer to the new type and deference it. This is allowed
484 by San Diego WP section 5.2.9 paragraph 12, though perhaps it
485 should be done directly (jason). (int &)ri ---> *(int*)&ri */
487 /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
489 if ((complain
& tf_warning
)
490 && TYPE_PTR_P (intype
)
491 && (comptypes (TREE_TYPE (intype
), type
,
492 COMPARE_BASE
| COMPARE_DERIVED
)))
493 warning_at (loc
, 0, "casting %qT to %qT does not dereference pointer",
496 rval
= cp_build_addr_expr (expr
, complain
);
497 if (rval
!= error_mark_node
)
498 rval
= convert_force (build_pointer_type (TREE_TYPE (reftype
)),
500 if (rval
!= error_mark_node
)
501 rval
= build1 (NOP_EXPR
, reftype
, rval
);
505 rval
= convert_for_initialization (NULL_TREE
, type
, expr
, flags
,
506 ICR_CONVERTING
, 0, 0, complain
);
507 if (rval
== NULL_TREE
|| rval
== error_mark_node
)
509 if (complain
& tf_error
)
510 diagnose_ref_binding (loc
, reftype
, intype
, decl
);
511 rval
= build_up_reference (reftype
, rval
, flags
, decl
, complain
);
516 /* If we found a way to convert earlier, then use it. */
520 if (complain
& tf_error
)
521 error_at (loc
, "cannot convert type %qT to type %qT", intype
, reftype
);
523 return error_mark_node
;
526 /* We are using a reference VAL for its value. Bash that reference all the
527 way down to its lowest form. */
530 convert_from_reference (tree val
)
533 && TREE_CODE (TREE_TYPE (val
)) == REFERENCE_TYPE
)
535 tree t
= TREE_TYPE (TREE_TYPE (val
));
536 tree ref
= build1 (INDIRECT_REF
, t
, val
);
539 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
540 so that we get the proper error message if the result is used
541 to assign to. Also, &* is supposed to be a no-op. */
542 TREE_READONLY (ref
) = CP_TYPE_CONST_P (t
);
543 TREE_THIS_VOLATILE (ref
) = CP_TYPE_VOLATILE_P (t
);
544 TREE_SIDE_EFFECTS (ref
)
545 = (TREE_THIS_VOLATILE (ref
) || TREE_SIDE_EFFECTS (val
));
552 /* Really perform an lvalue-to-rvalue conversion, including copying an
553 argument of class type into a temporary. */
556 force_rvalue (tree expr
, tsubst_flags_t complain
)
558 tree type
= TREE_TYPE (expr
);
559 if (MAYBE_CLASS_TYPE_P (type
) && TREE_CODE (expr
) != TARGET_EXPR
)
561 vec
<tree
, va_gc
> *args
= make_tree_vector_single (expr
);
562 expr
= build_special_member_call (NULL_TREE
, complete_ctor_identifier
,
563 &args
, type
, LOOKUP_NORMAL
, complain
);
564 release_tree_vector (args
);
565 expr
= build_cplus_new (type
, expr
, complain
);
568 expr
= decay_conversion (expr
, complain
);
574 /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has
575 TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR
579 ignore_overflows (tree expr
, tree orig
)
581 if (TREE_CODE (expr
) == INTEGER_CST
582 && TREE_CODE (orig
) == INTEGER_CST
583 && TREE_OVERFLOW (expr
) != TREE_OVERFLOW (orig
))
585 gcc_assert (!TREE_OVERFLOW (orig
));
586 /* Ensure constant sharing. */
587 expr
= wide_int_to_tree (TREE_TYPE (expr
), expr
);
592 /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
596 cp_fold_convert (tree type
, tree expr
)
599 if (TREE_TYPE (expr
) == type
)
601 else if (TREE_CODE (expr
) == PTRMEM_CST
)
603 /* Avoid wrapping a PTRMEM_CST in NOP_EXPR. */
604 conv
= copy_node (expr
);
605 TREE_TYPE (conv
) = type
;
609 conv
= fold_convert (type
, expr
);
610 conv
= ignore_overflows (conv
, expr
);
615 /* C++ conversions, preference to static cast conversions. */
618 cp_convert (tree type
, tree expr
, tsubst_flags_t complain
)
620 return ocp_convert (type
, expr
, CONV_OLD_CONVERT
, LOOKUP_NORMAL
, complain
);
623 /* C++ equivalent of convert_and_check but using cp_convert as the
626 Convert EXPR to TYPE, warning about conversion problems with constants.
627 Invoke this function on every expression that is converted implicitly,
628 i.e. because of language rules and not because of an explicit cast. */
631 cp_convert_and_check (tree type
, tree expr
, tsubst_flags_t complain
)
635 if (TREE_TYPE (expr
) == type
)
638 result
= cp_convert (type
, expr
, complain
);
640 if ((complain
& tf_warning
)
641 && c_inhibit_evaluation_warnings
== 0)
643 tree folded
= maybe_constant_value (expr
);
644 tree stripped
= folded
;
646 = folded
!= expr
? cp_convert (type
, folded
, complain
) : result
;
648 /* maybe_constant_value wraps an INTEGER_CST with TREE_OVERFLOW in a
649 NOP_EXPR so that it isn't TREE_CONSTANT anymore. */
650 STRIP_NOPS (stripped
);
652 if (!TREE_OVERFLOW_P (stripped
)
653 && folded_result
!= error_mark_node
)
654 warnings_for_convert_and_check (input_location
, type
, folded
,
663 FLAGS indicates how we should behave. */
666 ocp_convert (tree type
, tree expr
, int convtype
, int flags
,
667 tsubst_flags_t complain
)
670 enum tree_code code
= TREE_CODE (type
);
671 const char *invalid_conv_diag
;
673 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
675 if (error_operand_p (e
) || type
== error_mark_node
)
676 return error_mark_node
;
678 complete_type (type
);
679 complete_type (TREE_TYPE (expr
));
681 if ((invalid_conv_diag
682 = targetm
.invalid_conversion (TREE_TYPE (expr
), type
)))
684 if (complain
& tf_error
)
685 error (invalid_conv_diag
);
686 return error_mark_node
;
689 /* FIXME remove when moving to c_fully_fold model. */
690 if (!CLASS_TYPE_P (type
))
691 e
= scalar_constant_value (e
);
692 if (error_operand_p (e
))
693 return error_mark_node
;
695 if (MAYBE_CLASS_TYPE_P (type
) && (convtype
& CONV_FORCE_TEMP
))
696 /* We need a new temporary; don't take this shortcut. */;
697 else if (same_type_ignoring_top_level_qualifiers_p (type
, TREE_TYPE (e
)))
699 if (same_type_p (type
, TREE_TYPE (e
)))
700 /* The call to fold will not always remove the NOP_EXPR as
701 might be expected, since if one of the types is a typedef;
702 the comparison in fold is just equality of pointers, not a
703 call to comptypes. We don't call fold in this case because
704 that can result in infinite recursion; fold will call
705 convert, which will call ocp_convert, etc. */
707 /* For complex data types, we need to perform componentwise
709 else if (TREE_CODE (type
) == COMPLEX_TYPE
)
710 return fold_if_not_in_template (convert_to_complex (type
, e
));
711 else if (VECTOR_TYPE_P (type
))
712 return fold_if_not_in_template (convert_to_vector (type
, e
));
713 else if (TREE_CODE (e
) == TARGET_EXPR
)
715 /* Don't build a NOP_EXPR of class type. Instead, change the
716 type of the temporary. */
717 TREE_TYPE (e
) = TREE_TYPE (TARGET_EXPR_SLOT (e
)) = type
;
722 /* We shouldn't be treating objects of ADDRESSABLE type as
724 gcc_assert (!TREE_ADDRESSABLE (type
));
725 return fold_if_not_in_template (build_nop (type
, e
));
729 e1
= targetm
.convert_to_type (type
, e
);
733 if (code
== VOID_TYPE
&& (convtype
& CONV_STATIC
))
735 e
= convert_to_void (e
, ICV_CAST
, complain
);
739 if (INTEGRAL_CODE_P (code
))
741 tree intype
= TREE_TYPE (e
);
744 if (TREE_CODE (type
) == ENUMERAL_TYPE
)
746 /* enum = enum, enum = int, enum = float, (enum)pointer are all
748 if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype
)
749 || TREE_CODE (intype
) == REAL_TYPE
)
750 && ! (convtype
& CONV_STATIC
))
751 || TYPE_PTR_P (intype
))
753 if (complain
& tf_error
)
754 permerror (loc
, "conversion from %q#T to %q#T", intype
, type
);
756 return error_mark_node
;
759 /* [expr.static.cast]
761 8. A value of integral or enumeration type can be explicitly
762 converted to an enumeration type. The value is unchanged if
763 the original value is within the range of the enumeration
764 values. Otherwise, the resulting enumeration value is
766 if ((complain
& tf_warning
)
767 && TREE_CODE (e
) == INTEGER_CST
768 && ENUM_UNDERLYING_TYPE (type
)
769 && !int_fits_type_p (e
, ENUM_UNDERLYING_TYPE (type
)))
770 warning_at (loc
, OPT_Wconversion
,
771 "the result of the conversion is unspecified because "
772 "%qE is outside the range of type %qT",
775 if (MAYBE_CLASS_TYPE_P (intype
))
778 rval
= build_type_conversion (type
, e
);
781 if (complain
& tf_error
)
782 error_at (loc
, "%q#T used where a %qT was expected", intype
, type
);
783 return error_mark_node
;
785 if (code
== BOOLEAN_TYPE
)
787 if (VOID_TYPE_P (intype
))
789 if (complain
& tf_error
)
791 "could not convert %qE from %<void%> to %<bool%>",
793 return error_mark_node
;
796 /* We can't implicitly convert a scoped enum to bool, so convert
797 to the underlying type first. */
798 if (SCOPED_ENUM_P (intype
) && (convtype
& CONV_STATIC
))
799 e
= build_nop (ENUM_UNDERLYING_TYPE (intype
), e
);
800 return cp_truthvalue_conversion (e
);
803 converted
= fold_if_not_in_template (convert_to_integer (type
, e
));
805 /* Ignore any integer overflow caused by the conversion. */
806 return ignore_overflows (converted
, e
);
808 if (NULLPTR_TYPE_P (type
) && e
&& null_ptr_cst_p (e
))
810 if (complain
& tf_warning
)
811 maybe_warn_zero_as_null_pointer_constant (e
, loc
);
814 if (POINTER_TYPE_P (type
) || TYPE_PTRMEM_P (type
))
815 return fold_if_not_in_template (cp_convert_to_pointer (type
, e
, complain
));
816 if (code
== VECTOR_TYPE
)
818 tree in_vtype
= TREE_TYPE (e
);
819 if (MAYBE_CLASS_TYPE_P (in_vtype
))
822 ret_val
= build_type_conversion (type
, e
);
825 if (complain
& tf_error
)
826 error_at (loc
, "%q#T used where a %qT was expected",
828 return error_mark_node
;
830 return fold_if_not_in_template (convert_to_vector (type
, e
));
832 if (code
== REAL_TYPE
|| code
== COMPLEX_TYPE
)
834 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e
)))
837 rval
= build_type_conversion (type
, e
);
840 else if (complain
& tf_error
)
842 "%q#T used where a floating point value was expected",
845 if (code
== REAL_TYPE
)
846 return fold_if_not_in_template (convert_to_real (type
, e
));
847 else if (code
== COMPLEX_TYPE
)
848 return fold_if_not_in_template (convert_to_complex (type
, e
));
851 /* New C++ semantics: since assignment is now based on
852 memberwise copying, if the rhs type is derived from the
853 lhs type, then we may still do a conversion. */
854 if (RECORD_OR_UNION_CODE_P (code
))
856 tree dtype
= TREE_TYPE (e
);
857 tree ctor
= NULL_TREE
;
859 dtype
= TYPE_MAIN_VARIANT (dtype
);
861 /* Conversion between aggregate types. New C++ semantics allow
862 objects of derived type to be cast to objects of base type.
863 Old semantics only allowed this between pointers.
865 There may be some ambiguity between using a constructor
866 vs. using a type conversion operator when both apply. */
870 if (abstract_virtuals_error_sfinae (NULL_TREE
, type
, complain
))
871 return error_mark_node
;
873 if (BRACE_ENCLOSED_INITIALIZER_P (ctor
))
874 ctor
= perform_implicit_conversion (type
, ctor
, complain
);
875 else if ((flags
& LOOKUP_ONLYCONVERTING
)
876 && ! (CLASS_TYPE_P (dtype
) && DERIVED_FROM_P (type
, dtype
)))
877 /* For copy-initialization, first we create a temp of the proper type
878 with a user-defined conversion sequence, then we direct-initialize
879 the target with the temp (see [dcl.init]). */
880 ctor
= build_user_type_conversion (type
, ctor
, flags
, complain
);
883 vec
<tree
, va_gc
> *ctor_vec
= make_tree_vector_single (ctor
);
884 ctor
= build_special_member_call (NULL_TREE
,
885 complete_ctor_identifier
,
887 type
, flags
, complain
);
888 release_tree_vector (ctor_vec
);
891 return build_cplus_new (type
, ctor
, complain
);
894 if (complain
& tf_error
)
896 /* If the conversion failed and expr was an invalid use of pointer to
897 member function, try to report a meaningful error. */
898 if (invalid_nonstatic_memfn_p (loc
, expr
, complain
))
899 /* We displayed the error message. */;
901 error_at (loc
, "conversion from %qT to non-scalar type %qT requested",
902 TREE_TYPE (expr
), type
);
904 return error_mark_node
;
907 /* When an expression is used in a void context, its value is discarded and
908 no lvalue-rvalue and similar conversions happen [expr.static.cast/4,
909 stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type
910 in a void context. The C++ standard does not define what an `access' to an
911 object is, but there is reason to believe that it is the lvalue to rvalue
912 conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it
913 accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8
914 indicates that volatile semantics should be the same between C and C++
915 where ever possible. C leaves it implementation defined as to what
916 constitutes an access to a volatile. So, we interpret `*vp' as a read of
917 the volatile object `vp' points to, unless that is an incomplete type. For
918 volatile references we do not do this interpretation, because that would
919 make it impossible to ignore the reference return value from functions. We
920 issue warnings in the confusing cases.
922 The IMPLICIT is ICV_CAST when the user is explicitly converting an expression
923 to void via a cast. If an expression is being implicitly converted, IMPLICIT
924 indicates the context of the implicit conversion. */
927 convert_to_void (tree expr
, impl_conv_void implicit
, tsubst_flags_t complain
)
929 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
931 if (expr
== error_mark_node
932 || TREE_TYPE (expr
) == error_mark_node
)
933 return error_mark_node
;
935 if (implicit
== ICV_CAST
)
936 mark_exp_read (expr
);
941 while (TREE_CODE (exprv
) == COMPOUND_EXPR
)
942 exprv
= TREE_OPERAND (exprv
, 1);
944 || handled_component_p (exprv
)
945 || INDIRECT_REF_P (exprv
))
946 /* Expr is not being 'used' here, otherwise we whould have
947 called mark_{rl}value_use use here, which would have in turn
948 called mark_exp_read. Rather, we call mark_exp_read directly
949 to avoid some warnings when
950 -Wunused-but-set-{variable,parameter} is in effect. */
951 mark_exp_read (exprv
);
954 if (!TREE_TYPE (expr
))
956 if (invalid_nonstatic_memfn_p (loc
, expr
, complain
))
957 return error_mark_node
;
958 if (TREE_CODE (expr
) == PSEUDO_DTOR_EXPR
)
960 if (complain
& tf_error
)
961 error_at (loc
, "pseudo-destructor is not called");
962 return error_mark_node
;
964 if (VOID_TYPE_P (TREE_TYPE (expr
)))
966 switch (TREE_CODE (expr
))
970 /* The two parts of a cond expr might be separate lvalues. */
971 tree op1
= TREE_OPERAND (expr
,1);
972 tree op2
= TREE_OPERAND (expr
,2);
973 bool side_effects
= ((op1
&& TREE_SIDE_EFFECTS (op1
))
974 || TREE_SIDE_EFFECTS (op2
));
975 tree new_op1
, new_op2
;
977 if (implicit
!= ICV_CAST
&& !side_effects
)
980 new_op1
= convert_to_void (op1
, ICV_SECOND_OF_COND
, complain
);
981 new_op2
= convert_to_void (op2
, ICV_THIRD_OF_COND
, complain
);
986 new_op1
= convert_to_void (op1
, ICV_CAST
, complain
);
987 new_op2
= convert_to_void (op2
, ICV_CAST
, complain
);
990 expr
= build3 (COND_EXPR
, TREE_TYPE (new_op2
),
991 TREE_OPERAND (expr
, 0), new_op1
, new_op2
);
997 /* The second part of a compound expr contains the value. */
998 tree op1
= TREE_OPERAND (expr
,1);
1000 if (implicit
!= ICV_CAST
&& !TREE_NO_WARNING (expr
))
1001 new_op1
= convert_to_void (op1
, ICV_RIGHT_OF_COMMA
, complain
);
1003 new_op1
= convert_to_void (op1
, ICV_CAST
, complain
);
1007 tree t
= build2 (COMPOUND_EXPR
, TREE_TYPE (new_op1
),
1008 TREE_OPERAND (expr
, 0), new_op1
);
1015 case NON_LVALUE_EXPR
:
1017 /* These have already decayed to rvalue. */
1020 case CALL_EXPR
: /* We have a special meaning for volatile void fn(). */
1025 tree type
= TREE_TYPE (expr
);
1026 int is_reference
= TREE_CODE (TREE_TYPE (TREE_OPERAND (expr
, 0)))
1028 int is_volatile
= TYPE_VOLATILE (type
);
1029 int is_complete
= COMPLETE_TYPE_P (complete_type (type
));
1031 /* Can't load the value if we don't know the type. */
1032 if (is_volatile
&& !is_complete
)
1034 if (complain
& tf_warning
)
1038 warning_at (loc
, 0, "conversion to void will not access "
1039 "object of incomplete type %qT", type
);
1041 case ICV_SECOND_OF_COND
:
1042 warning_at (loc
, 0, "indirection will not access object of "
1043 "incomplete type %qT in second operand "
1044 "of conditional expression", type
);
1046 case ICV_THIRD_OF_COND
:
1047 warning_at (loc
, 0, "indirection will not access object of "
1048 "incomplete type %qT in third operand "
1049 "of conditional expression", type
);
1051 case ICV_RIGHT_OF_COMMA
:
1052 warning_at (loc
, 0, "indirection will not access object of "
1053 "incomplete type %qT in right operand of "
1054 "comma operator", type
);
1056 case ICV_LEFT_OF_COMMA
:
1057 warning_at (loc
, 0, "indirection will not access object of "
1058 "incomplete type %qT in left operand of "
1059 "comma operator", type
);
1062 warning_at (loc
, 0, "indirection will not access object of "
1063 "incomplete type %qT in statement", type
);
1065 case ICV_THIRD_IN_FOR
:
1066 warning_at (loc
, 0, "indirection will not access object of "
1067 "incomplete type %qT in for increment "
1068 "expression", type
);
1074 /* Don't load the value if this is an implicit dereference, or if
1075 the type needs to be handled by ctors/dtors. */
1076 else if (is_volatile
&& is_reference
)
1078 if (complain
& tf_warning
)
1082 warning_at (loc
, 0, "conversion to void will not access "
1083 "object of type %qT", type
);
1085 case ICV_SECOND_OF_COND
:
1086 warning_at (loc
, 0, "implicit dereference will not access "
1087 "object of type %qT in second operand of "
1088 "conditional expression", type
);
1090 case ICV_THIRD_OF_COND
:
1091 warning_at (loc
, 0, "implicit dereference will not access "
1092 "object of type %qT in third operand of "
1093 "conditional expression", type
);
1095 case ICV_RIGHT_OF_COMMA
:
1096 warning_at (loc
, 0, "implicit dereference will not access "
1097 "object of type %qT in right operand of "
1098 "comma operator", type
);
1100 case ICV_LEFT_OF_COMMA
:
1101 warning_at (loc
, 0, "implicit dereference will not access "
1102 "object of type %qT in left operand of comma "
1106 warning_at (loc
, 0, "implicit dereference will not access "
1107 "object of type %qT in statement", type
);
1109 case ICV_THIRD_IN_FOR
:
1110 warning_at (loc
, 0, "implicit dereference will not access "
1111 "object of type %qT in for increment expression",
1118 else if (is_volatile
&& TREE_ADDRESSABLE (type
))
1120 if (complain
& tf_warning
)
1124 warning_at (loc
, 0, "conversion to void will not access "
1125 "object of non-trivially-copyable type %qT",
1128 case ICV_SECOND_OF_COND
:
1129 warning_at (loc
, 0, "indirection will not access object of "
1130 "non-trivially-copyable type %qT in second "
1131 "operand of conditional expression", type
);
1133 case ICV_THIRD_OF_COND
:
1134 warning_at (loc
, 0, "indirection will not access object of "
1135 "non-trivially-copyable type %qT in third "
1136 "operand of conditional expression", type
);
1138 case ICV_RIGHT_OF_COMMA
:
1139 warning_at (loc
, 0, "indirection will not access object of "
1140 "non-trivially-copyable type %qT in right "
1141 "operand of comma operator", type
);
1143 case ICV_LEFT_OF_COMMA
:
1144 warning_at (loc
, 0, "indirection will not access object of "
1145 "non-trivially-copyable type %qT in left "
1146 "operand of comma operator", type
);
1149 warning_at (loc
, 0, "indirection will not access object of "
1150 "non-trivially-copyable type %qT in statement",
1153 case ICV_THIRD_IN_FOR
:
1154 warning_at (loc
, 0, "indirection will not access object of "
1155 "non-trivially-copyable type %qT in for "
1156 "increment expression", type
);
1162 if (is_reference
|| !is_volatile
|| !is_complete
|| TREE_ADDRESSABLE (type
))
1164 /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
1165 operation is stripped off. Note that we don't warn about
1166 - an expression with TREE_NO_WARNING set. (For an example of
1167 such expressions, see build_over_call in call.c.)
1168 - automatic dereferencing of references, since the user cannot
1169 control it. (See also warn_if_unused_value() in c-common.c.) */
1170 if (warn_unused_value
1171 && implicit
!= ICV_CAST
1172 && (complain
& tf_warning
)
1173 && !TREE_NO_WARNING (expr
)
1175 warning_at (loc
, OPT_Wunused_value
, "value computed is not used");
1176 expr
= TREE_OPERAND (expr
, 0);
1184 /* External variables might be incomplete. */
1185 tree type
= TREE_TYPE (expr
);
1186 int is_complete
= COMPLETE_TYPE_P (complete_type (type
));
1188 if (TYPE_VOLATILE (type
) && !is_complete
&& (complain
& tf_warning
))
1192 warning_at (loc
, 0, "conversion to void will not access "
1193 "object %qE of incomplete type %qT", expr
, type
);
1195 case ICV_SECOND_OF_COND
:
1196 warning_at (loc
, 0, "variable %qE of incomplete type %qT will "
1197 "not be accessed in second operand of "
1198 "conditional expression", expr
, type
);
1200 case ICV_THIRD_OF_COND
:
1201 warning_at (loc
, 0, "variable %qE of incomplete type %qT will "
1202 "not be accessed in third operand of "
1203 "conditional expression", expr
, type
);
1205 case ICV_RIGHT_OF_COMMA
:
1206 warning_at (loc
, 0, "variable %qE of incomplete type %qT will "
1207 "not be accessed in right operand of comma operator",
1210 case ICV_LEFT_OF_COMMA
:
1211 warning_at (loc
, 0, "variable %qE of incomplete type %qT will "
1212 "not be accessed in left operand of comma operator",
1216 warning_at (loc
, 0, "variable %qE of incomplete type %qT will "
1217 "not be accessed in statement", expr
, type
);
1219 case ICV_THIRD_IN_FOR
:
1220 warning_at (loc
, 0, "variable %qE of incomplete type %qT will "
1221 "not be accessed in for increment expression",
1232 /* Don't bother with the temporary object returned from a function if
1233 we don't use it and don't need to destroy it. We'll still
1234 allocate space for it in expand_call or declare_return_variable,
1235 but we don't need to track it through all the tree phases. */
1236 if (TARGET_EXPR_IMPLICIT_P (expr
)
1237 && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr
)))
1239 tree init
= TARGET_EXPR_INITIAL (expr
);
1240 if (TREE_CODE (init
) == AGGR_INIT_EXPR
1241 && !AGGR_INIT_VIA_CTOR_P (init
))
1243 tree fn
= AGGR_INIT_EXPR_FN (init
);
1244 expr
= build_call_array_loc (input_location
,
1245 TREE_TYPE (TREE_TYPE (TREE_TYPE (fn
))),
1247 aggr_init_expr_nargs (init
),
1248 AGGR_INIT_EXPR_ARGP (init
));
1255 expr
= resolve_nondeduced_context (expr
);
1259 if (TREE_CODE (probe
) == ADDR_EXPR
)
1260 probe
= TREE_OPERAND (expr
, 0);
1261 if (type_unknown_p (probe
))
1263 /* [over.over] enumerates the places where we can take the address
1264 of an overloaded function, and this is not one of them. */
1265 if (complain
& tf_error
)
1269 error_at (loc
, "conversion to void "
1270 "cannot resolve address of overloaded function");
1272 case ICV_SECOND_OF_COND
:
1273 error_at (loc
, "second operand of conditional expression "
1274 "cannot resolve address of overloaded function");
1276 case ICV_THIRD_OF_COND
:
1277 error_at (loc
, "third operand of conditional expression "
1278 "cannot resolve address of overloaded function");
1280 case ICV_RIGHT_OF_COMMA
:
1281 error_at (loc
, "right operand of comma operator "
1282 "cannot resolve address of overloaded function");
1284 case ICV_LEFT_OF_COMMA
:
1285 error_at (loc
, "left operand of comma operator "
1286 "cannot resolve address of overloaded function");
1289 error_at (loc
, "statement "
1290 "cannot resolve address of overloaded function");
1292 case ICV_THIRD_IN_FOR
:
1293 error_at (loc
, "for increment expression "
1294 "cannot resolve address of overloaded function");
1298 return error_mark_node
;
1301 else if (implicit
!= ICV_CAST
&& probe
== expr
&& is_overloaded_fn (probe
))
1303 /* Only warn when there is no &. */
1304 if (complain
& tf_warning
)
1307 case ICV_SECOND_OF_COND
:
1308 warning_at (loc
, OPT_Waddress
,
1309 "second operand of conditional expression "
1310 "is a reference, not call, to function %qE", expr
);
1312 case ICV_THIRD_OF_COND
:
1313 warning_at (loc
, OPT_Waddress
,
1314 "third operand of conditional expression "
1315 "is a reference, not call, to function %qE", expr
);
1317 case ICV_RIGHT_OF_COMMA
:
1318 warning_at (loc
, OPT_Waddress
,
1319 "right operand of comma operator "
1320 "is a reference, not call, to function %qE", expr
);
1322 case ICV_LEFT_OF_COMMA
:
1323 warning_at (loc
, OPT_Waddress
,
1324 "left operand of comma operator "
1325 "is a reference, not call, to function %qE", expr
);
1328 warning_at (loc
, OPT_Waddress
,
1329 "statement is a reference, not call, to function %qE",
1332 case ICV_THIRD_IN_FOR
:
1333 warning_at (loc
, OPT_Waddress
,
1334 "for increment expression "
1335 "is a reference, not call, to function %qE", expr
);
1341 if (TREE_CODE (expr
) == COMPONENT_REF
)
1342 expr
= TREE_OPERAND (expr
, 0);
1346 if (expr
!= error_mark_node
&& !VOID_TYPE_P (TREE_TYPE (expr
)))
1348 if (implicit
!= ICV_CAST
1349 && warn_unused_value
1350 && !TREE_NO_WARNING (expr
)
1351 && !processing_template_decl
)
1353 /* The middle end does not warn about expressions that have
1354 been explicitly cast to void, so we must do so here. */
1355 if (!TREE_SIDE_EFFECTS (expr
)) {
1356 if (complain
& tf_warning
)
1359 case ICV_SECOND_OF_COND
:
1360 warning_at (loc
, OPT_Wunused_value
,
1361 "second operand of conditional expression "
1364 case ICV_THIRD_OF_COND
:
1365 warning_at (loc
, OPT_Wunused_value
,
1366 "third operand of conditional expression "
1369 case ICV_RIGHT_OF_COMMA
:
1370 warning_at (loc
, OPT_Wunused_value
,
1371 "right operand of comma operator has no effect");
1373 case ICV_LEFT_OF_COMMA
:
1374 warning_at (loc
, OPT_Wunused_value
,
1375 "left operand of comma operator has no effect");
1378 warning_at (loc
, OPT_Wunused_value
,
1379 "statement has no effect");
1381 case ICV_THIRD_IN_FOR
:
1382 warning_at (loc
, OPT_Wunused_value
,
1383 "for increment expression has no effect");
1392 enum tree_code code
;
1393 enum tree_code_class tclass
;
1396 /* We might like to warn about (say) "(int) f()", as the
1397 cast has no effect, but the compiler itself will
1398 generate implicit conversions under some
1399 circumstances. (For example a block copy will be
1400 turned into a call to "__builtin_memcpy", with a
1401 conversion of the return value to an appropriate
1402 type.) So, to avoid false positives, we strip
1403 conversions. Do not use STRIP_NOPs because it will
1404 not strip conversions to "void", as that is not a
1405 mode-preserving conversion. */
1406 while (TREE_CODE (e
) == NOP_EXPR
)
1407 e
= TREE_OPERAND (e
, 0);
1409 code
= TREE_CODE (e
);
1410 tclass
= TREE_CODE_CLASS (code
);
1411 if ((tclass
== tcc_comparison
1412 || tclass
== tcc_unary
1413 || (tclass
== tcc_binary
1414 && !(code
== MODIFY_EXPR
1415 || code
== INIT_EXPR
1416 || code
== PREDECREMENT_EXPR
1417 || code
== PREINCREMENT_EXPR
1418 || code
== POSTDECREMENT_EXPR
1419 || code
== POSTINCREMENT_EXPR
))
1420 || code
== VEC_PERM_EXPR
1421 || code
== VEC_COND_EXPR
)
1422 && (complain
& tf_warning
))
1423 warning_at (loc
, OPT_Wunused_value
, "value computed is not used");
1426 expr
= build1 (CONVERT_EXPR
, void_type_node
, expr
);
1428 if (! TREE_SIDE_EFFECTS (expr
))
1433 /* Create an expression whose value is that of EXPR,
1434 converted to type TYPE. The TREE_TYPE of the value
1435 is always TYPE. This function implements all reasonable
1436 conversions; callers should filter out those that are
1437 not permitted by the language being compiled.
1439 Most of this routine is from build_reinterpret_cast.
1441 The back end cannot call cp_convert (what was convert) because
1442 conversions to/from basetypes may involve memory references
1443 (vbases) and adding or subtracting small values (multiple
1444 inheritance), but it calls convert from the constant folding code
1445 on subtrees of already built trees after it has ripped them apart.
1447 Also, if we ever support range variables, we'll probably also have to
1448 do a little bit more work. */
1451 convert (tree type
, tree expr
)
1455 if (type
== error_mark_node
|| expr
== error_mark_node
)
1456 return error_mark_node
;
1458 intype
= TREE_TYPE (expr
);
1460 if (POINTER_TYPE_P (type
) && POINTER_TYPE_P (intype
))
1461 return fold_if_not_in_template (build_nop (type
, expr
));
1463 return ocp_convert (type
, expr
, CONV_OLD_CONVERT
,
1464 LOOKUP_NORMAL
|LOOKUP_NO_CONVERSION
,
1465 tf_warning_or_error
);
1468 /* Like cp_convert, except permit conversions to take place which
1469 are not normally allowed due to access restrictions
1470 (such as conversion from sub-type to private super-type). */
1473 convert_force (tree type
, tree expr
, int convtype
, tsubst_flags_t complain
)
1476 enum tree_code code
= TREE_CODE (type
);
1478 if (code
== REFERENCE_TYPE
)
1479 return (fold_if_not_in_template
1480 (convert_to_reference (type
, e
, CONV_C_CAST
, 0,
1481 NULL_TREE
, complain
)));
1483 if (code
== POINTER_TYPE
)
1484 return fold_if_not_in_template (convert_to_pointer_force (type
, e
,
1487 /* From typeck.c convert_for_assignment */
1488 if (((TYPE_PTR_P (TREE_TYPE (e
)) && TREE_CODE (e
) == ADDR_EXPR
1489 && TREE_CODE (TREE_TYPE (TREE_TYPE (e
))) == METHOD_TYPE
)
1490 || integer_zerop (e
)
1491 || TYPE_PTRMEMFUNC_P (TREE_TYPE (e
)))
1492 && TYPE_PTRMEMFUNC_P (type
))
1493 /* compatible pointer to member functions. */
1494 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type
), e
, 1,
1495 /*c_cast_p=*/1, complain
);
1497 return ocp_convert (type
, e
, CONV_C_CAST
|convtype
, LOOKUP_NORMAL
, complain
);
1500 /* Convert an aggregate EXPR to type XTYPE. If a conversion
1501 exists, return the attempted conversion. This may
1502 return ERROR_MARK_NODE if the conversion is not
1503 allowed (references private members, etc).
1504 If no conversion exists, NULL_TREE is returned.
1506 FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1507 object parameter, or by the second standard conversion sequence if
1508 that doesn't do it. This will probably wait for an overloading rewrite.
1512 build_type_conversion (tree xtype
, tree expr
)
1514 /* C++: check to see if we can convert this aggregate type
1515 into the required type. */
1516 return build_user_type_conversion (xtype
, expr
, LOOKUP_NORMAL
,
1517 tf_warning_or_error
);
1520 /* Convert the given EXPR to one of a group of types suitable for use in an
1521 expression. DESIRES is a combination of various WANT_* flags (q.v.)
1522 which indicates which types are suitable. If COMPLAIN is true, complain
1523 about ambiguity; otherwise, the caller will deal with it. */
1526 build_expr_type_conversion (int desires
, tree expr
, bool complain
)
1528 tree basetype
= TREE_TYPE (expr
);
1529 tree conv
= NULL_TREE
;
1530 tree winner
= NULL_TREE
;
1532 if (expr
== null_node
1533 && (desires
& WANT_INT
)
1534 && !(desires
& WANT_NULL
))
1536 source_location loc
=
1537 expansion_point_location_if_in_system_header (input_location
);
1539 warning_at (loc
, OPT_Wconversion_null
,
1540 "converting NULL to non-pointer type");
1543 if (basetype
== error_mark_node
)
1544 return error_mark_node
;
1546 if (! MAYBE_CLASS_TYPE_P (basetype
))
1547 switch (TREE_CODE (basetype
))
1550 if ((desires
& WANT_NULL
) && null_ptr_cst_p (expr
))
1552 /* else fall through... */
1555 return (desires
& WANT_INT
) ? expr
: NULL_TREE
;
1557 return (desires
& WANT_ENUM
) ? expr
: NULL_TREE
;
1559 return (desires
& WANT_FLOAT
) ? expr
: NULL_TREE
;
1561 return (desires
& WANT_POINTER
) ? expr
: NULL_TREE
;
1565 return (desires
& WANT_POINTER
) ? decay_conversion (expr
,
1566 tf_warning_or_error
)
1571 if ((desires
& WANT_VECTOR_OR_COMPLEX
) == 0)
1573 switch (TREE_CODE (TREE_TYPE (basetype
)))
1577 return (desires
& WANT_INT
) ? expr
: NULL_TREE
;
1579 return (desires
& WANT_ENUM
) ? expr
: NULL_TREE
;
1581 return (desires
& WANT_FLOAT
) ? expr
: NULL_TREE
;
1590 /* The code for conversions from class type is currently only used for
1591 delete expressions. Other expressions are handled by build_new_op. */
1592 if (!complete_type_or_maybe_complain (basetype
, expr
, complain
))
1593 return error_mark_node
;
1594 if (!TYPE_HAS_CONVERSION (basetype
))
1597 for (conv
= lookup_conversions (basetype
); conv
; conv
= TREE_CHAIN (conv
))
1601 tree cand
= TREE_VALUE (conv
);
1602 cand
= OVL_CURRENT (cand
);
1604 if (winner
&& winner
== cand
)
1607 if (DECL_NONCONVERTING_P (cand
))
1610 candidate
= non_reference (TREE_TYPE (TREE_TYPE (cand
)));
1612 switch (TREE_CODE (candidate
))
1616 win
= (desires
& WANT_INT
); break;
1618 win
= (desires
& WANT_ENUM
); break;
1620 win
= (desires
& WANT_FLOAT
); break;
1622 win
= (desires
& WANT_POINTER
); break;
1626 if ((desires
& WANT_VECTOR_OR_COMPLEX
) == 0)
1628 switch (TREE_CODE (TREE_TYPE (candidate
)))
1632 win
= (desires
& WANT_INT
); break;
1634 win
= (desires
& WANT_ENUM
); break;
1636 win
= (desires
& WANT_FLOAT
); break;
1643 /* A wildcard could be instantiated to match any desired
1644 type, but we can't deduce the template argument. */
1645 if (WILDCARD_TYPE_P (candidate
))
1652 if (TREE_CODE (cand
) == TEMPLATE_DECL
)
1655 error ("default type conversion can't deduce template"
1656 " argument for %qD", cand
);
1657 return error_mark_node
;
1663 = non_reference (TREE_TYPE (TREE_TYPE (winner
)));
1665 if (!same_type_ignoring_top_level_qualifiers_p (winner_type
,
1670 error ("ambiguous default type conversion from %qT",
1672 inform (input_location
,
1673 " candidate conversions include %qD and %qD",
1676 return error_mark_node
;
1686 tree type
= non_reference (TREE_TYPE (TREE_TYPE (winner
)));
1687 return build_user_type_conversion (type
, expr
, LOOKUP_NORMAL
,
1688 tf_warning_or_error
);
1694 /* Implements integral promotion (4.1) and float->double promotion. */
1697 type_promotes_to (tree type
)
1701 if (type
== error_mark_node
)
1702 return error_mark_node
;
1704 type
= TYPE_MAIN_VARIANT (type
);
1706 /* Check for promotions of target-defined types first. */
1707 promoted_type
= targetm
.promoted_type (type
);
1709 return promoted_type
;
1711 /* bool always promotes to int (not unsigned), even if it's the same
1713 if (TREE_CODE (type
) == BOOLEAN_TYPE
)
1714 type
= integer_type_node
;
1716 /* Normally convert enums to int, but convert wide enums to something
1717 wider. Scoped enums don't promote, but pretend they do for backward
1718 ABI bug compatibility wrt varargs. */
1719 else if (TREE_CODE (type
) == ENUMERAL_TYPE
1720 || type
== char16_type_node
1721 || type
== char32_type_node
1722 || type
== wchar_type_node
)
1724 int precision
= MAX (TYPE_PRECISION (type
),
1725 TYPE_PRECISION (integer_type_node
));
1726 tree totype
= c_common_type_for_size (precision
, 0);
1728 if (TREE_CODE (prom
) == ENUMERAL_TYPE
)
1729 prom
= ENUM_UNDERLYING_TYPE (prom
);
1730 if (TYPE_UNSIGNED (prom
)
1731 && ! int_fits_type_p (TYPE_MAX_VALUE (prom
), totype
))
1732 prom
= c_common_type_for_size (precision
, 1);
1735 if (SCOPED_ENUM_P (type
))
1737 if (abi_version_crosses (6)
1738 && TYPE_MODE (prom
) != TYPE_MODE (type
))
1739 warning (OPT_Wabi
, "scoped enum %qT passed through ... as "
1740 "%qT before -fabi-version=6, %qT after",
1741 type
, prom
, ENUM_UNDERLYING_TYPE (type
));
1742 if (!abi_version_at_least (6))
1748 else if (c_promoting_integer_type_p (type
))
1750 /* Retain unsignedness if really not getting bigger. */
1751 if (TYPE_UNSIGNED (type
)
1752 && TYPE_PRECISION (type
) == TYPE_PRECISION (integer_type_node
))
1753 type
= unsigned_type_node
;
1755 type
= integer_type_node
;
1757 else if (type
== float_type_node
)
1758 type
= double_type_node
;
1763 /* The routines below this point are carefully written to conform to
1764 the standard. They use the same terminology, and follow the rules
1765 closely. Although they are used only in pt.c at the moment, they
1766 should presumably be used everywhere in the future. */
1768 /* Attempt to perform qualification conversions on EXPR to convert it
1769 to TYPE. Return the resulting expression, or error_mark_node if
1770 the conversion was impossible. */
1773 perform_qualification_conversions (tree type
, tree expr
)
1777 expr_type
= TREE_TYPE (expr
);
1779 if (same_type_p (type
, expr_type
))
1781 else if (TYPE_PTR_P (type
) && TYPE_PTR_P (expr_type
)
1782 && comp_ptr_ttypes (TREE_TYPE (type
), TREE_TYPE (expr_type
)))
1783 return build_nop (type
, expr
);
1784 else if (TYPE_PTRMEM_P (type
) && TYPE_PTRMEM_P (expr_type
)
1785 && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type
),
1786 TYPE_PTRMEM_CLASS_TYPE (expr_type
))
1787 && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type
),
1788 TYPE_PTRMEM_POINTED_TO_TYPE (expr_type
)))
1789 return build_nop (type
, expr
);
1791 return error_mark_node
;
1794 /* True iff T is a transaction-safe function type. */
1797 tx_safe_fn_type_p (tree t
)
1799 if (TREE_CODE (t
) != FUNCTION_TYPE
1800 && TREE_CODE (t
) != METHOD_TYPE
)
1802 return !!lookup_attribute ("transaction_safe", TYPE_ATTRIBUTES (t
));
1805 /* Return the transaction-unsafe variant of transaction-safe function type
1809 tx_unsafe_fn_variant (tree t
)
1811 gcc_assert (tx_safe_fn_type_p (t
));
1812 tree attrs
= remove_attribute ("transaction_safe",
1813 TYPE_ATTRIBUTES (t
));
1814 return cp_build_type_attribute_variant (t
, attrs
);
1817 /* Return true iff FROM can convert to TO by a transaction-safety
1821 can_convert_tx_safety (tree to
, tree from
)
1823 return (flag_tm
&& tx_safe_fn_type_p (from
)
1824 && same_type_p (to
, tx_unsafe_fn_variant (from
)));