1 /* Language-level data type conversion for GNU C++.
2 Copyright (C) 1987-2016 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"
32 #include "stor-layout.h"
37 static tree
convert_to_pointer_force (tree
, tree
, tsubst_flags_t
);
38 static tree
build_type_conversion (tree
, tree
);
39 static tree
build_up_reference (tree
, tree
, int, tree
, tsubst_flags_t
);
40 static void diagnose_ref_binding (location_t
, tree
, tree
, tree
);
42 /* Change of width--truncation and extension of integers or reals--
43 is represented with NOP_EXPR. Proper functioning of many things
44 assumes that no other conversions can be NOP_EXPRs.
46 Conversion between integer and pointer is represented with CONVERT_EXPR.
47 Converting integer to real uses FLOAT_EXPR
48 and real to integer uses FIX_TRUNC_EXPR.
50 Here is a list of all the functions that assume that widening and
51 narrowing is always done with a NOP_EXPR:
52 In convert.c, convert_to_integer[_maybe_fold].
53 In c-typeck.c, build_binary_op_nodefault (boolean ops),
54 and c_common_truthvalue_conversion.
55 In expr.c: expand_expr, for operands of a MULT_EXPR.
56 In fold-const.c: fold.
57 In tree.c: get_narrower and get_unwidened.
59 C++: in multiple-inheritance, converting between pointers may involve
60 adjusting them by a delta stored within the class definition. */
62 /* Subroutines of `convert'. */
64 /* if converting pointer to pointer
65 if dealing with classes, check for derived->base or vice versa
66 else if dealing with method pointers, delegate
68 else if converting class, pass off to build_type_conversion
69 else try C-style pointer conversion. */
72 cp_convert_to_pointer (tree type
, tree expr
, bool dofold
,
73 tsubst_flags_t complain
)
75 tree intype
= TREE_TYPE (expr
);
78 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
80 if (intype
== error_mark_node
)
81 return error_mark_node
;
83 if (MAYBE_CLASS_TYPE_P (intype
))
85 intype
= complete_type (intype
);
86 if (!COMPLETE_TYPE_P (intype
))
88 if (complain
& tf_error
)
89 error_at (loc
, "can%'t convert from incomplete type %qT to %qT",
91 return error_mark_node
;
94 rval
= build_type_conversion (type
, expr
);
97 if ((complain
& tf_error
)
98 && rval
== error_mark_node
)
99 error_at (loc
, "conversion of %qE from %qT to %qT is ambiguous",
105 /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
106 if (TYPE_PTR_P (type
)
107 && (TREE_CODE (TREE_TYPE (type
)) == FUNCTION_TYPE
108 || VOID_TYPE_P (TREE_TYPE (type
))))
110 if (TYPE_PTRMEMFUNC_P (intype
)
111 || TREE_CODE (intype
) == METHOD_TYPE
)
112 return convert_member_func_to_ptr (type
, expr
, complain
);
113 if (TYPE_PTR_P (TREE_TYPE (expr
)))
114 return build_nop (type
, expr
);
115 intype
= TREE_TYPE (expr
);
118 if (expr
== error_mark_node
)
119 return error_mark_node
;
121 form
= TREE_CODE (intype
);
123 if (POINTER_TYPE_P (intype
))
125 intype
= TYPE_MAIN_VARIANT (intype
);
127 if (TYPE_MAIN_VARIANT (type
) != intype
129 && TREE_CODE (TREE_TYPE (type
)) == RECORD_TYPE
130 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type
))
131 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype
))
132 && TREE_CODE (TREE_TYPE (intype
)) == RECORD_TYPE
)
134 enum tree_code code
= PLUS_EXPR
;
140 intype_class
= TREE_TYPE (intype
);
141 type_class
= TREE_TYPE (type
);
143 same_p
= same_type_p (TYPE_MAIN_VARIANT (intype_class
),
144 TYPE_MAIN_VARIANT (type_class
));
146 /* Try derived to base conversion. */
148 binfo
= lookup_base (intype_class
, type_class
, ba_check
,
150 if (!same_p
&& !binfo
)
152 /* Try base to derived conversion. */
153 binfo
= lookup_base (type_class
, intype_class
, ba_check
,
157 if (binfo
== error_mark_node
)
158 return error_mark_node
;
162 expr
= build_base_path (code
, expr
, binfo
, 0, complain
);
163 /* Add any qualifier conversions. */
164 return build_nop (type
, expr
);
168 if (TYPE_PTRMEMFUNC_P (type
))
170 if (complain
& tf_error
)
171 error_at (loc
, "cannot convert %qE from type %qT to type %qT",
173 return error_mark_node
;
176 return build_nop (type
, expr
);
178 else if ((TYPE_PTRDATAMEM_P (type
) && TYPE_PTRDATAMEM_P (intype
))
179 || (TYPE_PTRMEMFUNC_P (type
) && TYPE_PTRMEMFUNC_P (intype
)))
180 return convert_ptrmem (type
, expr
, /*allow_inverse_p=*/false,
181 /*c_cast_p=*/false, complain
);
182 else if (TYPE_PTRMEMFUNC_P (intype
))
186 if (TREE_CODE (expr
) == PTRMEM_CST
)
187 return cp_convert_to_pointer (type
, PTRMEM_CST_MEMBER (expr
),
189 else if (TREE_CODE (expr
) == OFFSET_REF
)
191 tree object
= TREE_OPERAND (expr
, 0);
192 return get_member_function_from_ptrfunc (&object
,
193 TREE_OPERAND (expr
, 1),
197 if (complain
& tf_error
)
198 error_at (loc
, "cannot convert %qE from type %qT to type %qT",
200 return error_mark_node
;
203 if (null_ptr_cst_p (expr
))
205 if (TYPE_PTRMEMFUNC_P (type
))
206 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type
), expr
, 0,
207 /*c_cast_p=*/false, complain
);
209 if (complain
& tf_warning
)
210 maybe_warn_zero_as_null_pointer_constant (expr
, loc
);
212 /* A NULL pointer-to-data-member is represented by -1, not by
214 tree val
= (TYPE_PTRDATAMEM_P (type
)
215 ? build_int_cst_type (type
, -1)
216 : build_int_cst (type
, 0));
218 return (TREE_SIDE_EFFECTS (expr
)
219 ? build2 (COMPOUND_EXPR
, type
, expr
, val
) : val
);
221 else if (TYPE_PTRMEM_P (type
) && INTEGRAL_CODE_P (form
))
223 if (complain
& tf_error
)
224 error_at (loc
, "invalid conversion from %qT to %qT", intype
, type
);
225 return error_mark_node
;
228 if (INTEGRAL_CODE_P (form
))
230 if (TYPE_PRECISION (intype
) == POINTER_SIZE
)
231 return build1 (CONVERT_EXPR
, type
, expr
);
232 expr
= cp_convert (c_common_type_for_size (POINTER_SIZE
, 0), expr
,
234 /* Modes may be different but sizes should be the same. There
235 is supposed to be some integral type that is the same width
237 gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr
)))
238 == GET_MODE_SIZE (TYPE_MODE (type
)));
240 return convert_to_pointer_maybe_fold (type
, expr
, dofold
);
243 if (type_unknown_p (expr
))
244 return instantiate_type (type
, expr
, complain
);
246 if (complain
& tf_error
)
247 error_at (loc
, "cannot convert %qE from type %qT to type %qT",
249 return error_mark_node
;
252 /* Like convert, except permit conversions to take place which
253 are not normally allowed due to access restrictions
254 (such as conversion from sub-type to private super-type). */
257 convert_to_pointer_force (tree type
, tree expr
, tsubst_flags_t complain
)
259 tree intype
= TREE_TYPE (expr
);
260 enum tree_code form
= TREE_CODE (intype
);
262 if (form
== POINTER_TYPE
)
264 intype
= TYPE_MAIN_VARIANT (intype
);
266 if (TYPE_MAIN_VARIANT (type
) != intype
267 && TREE_CODE (TREE_TYPE (type
)) == RECORD_TYPE
268 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type
))
269 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype
))
270 && TREE_CODE (TREE_TYPE (intype
)) == RECORD_TYPE
)
272 enum tree_code code
= PLUS_EXPR
;
275 binfo
= lookup_base (TREE_TYPE (intype
), TREE_TYPE (type
),
276 ba_unique
, NULL
, complain
);
279 binfo
= lookup_base (TREE_TYPE (type
), TREE_TYPE (intype
),
280 ba_unique
, NULL
, complain
);
283 if (binfo
== error_mark_node
)
284 return error_mark_node
;
287 expr
= build_base_path (code
, expr
, binfo
, 0, complain
);
288 if (expr
== error_mark_node
)
289 return error_mark_node
;
290 /* Add any qualifier conversions. */
291 if (!same_type_p (TREE_TYPE (TREE_TYPE (expr
)),
293 expr
= build_nop (type
, expr
);
299 return cp_convert_to_pointer (type
, expr
, /*fold*/false, complain
);
302 /* We are passing something to a function which requires a reference.
303 The type we are interested in is in TYPE. The initial
304 value we have to begin with is in ARG.
306 FLAGS controls how we manage access checking.
307 DIRECT_BIND in FLAGS controls how any temporaries are generated.
308 If DIRECT_BIND is set, DECL is the reference we're binding to. */
311 build_up_reference (tree type
, tree arg
, int flags
, tree decl
,
312 tsubst_flags_t complain
)
315 tree argtype
= TREE_TYPE (arg
);
316 tree target_type
= TREE_TYPE (type
);
318 gcc_assert (TREE_CODE (type
) == REFERENCE_TYPE
);
320 if ((flags
& DIRECT_BIND
) && ! real_lvalue_p (arg
))
322 /* Create a new temporary variable. We can't just use a TARGET_EXPR
323 here because it needs to live as long as DECL. */
326 arg
= make_temporary_var_for_ref_to_temp (decl
, target_type
);
328 /* Process the initializer for the declaration. */
329 DECL_INITIAL (arg
) = targ
;
330 cp_finish_decl (arg
, targ
, /*init_const_expr_p=*/false, NULL_TREE
,
331 LOOKUP_ONLYCONVERTING
|DIRECT_BIND
);
333 else if (!(flags
& DIRECT_BIND
) && ! lvalue_p (arg
))
334 return get_target_expr_sfinae (arg
, complain
);
336 /* If we had a way to wrap this up, and say, if we ever needed its
337 address, transform all occurrences of the register, into a memory
338 reference we could win better. */
339 rval
= cp_build_addr_expr (arg
, complain
);
340 if (rval
== error_mark_node
)
341 return error_mark_node
;
343 if ((flags
& LOOKUP_PROTECT
)
344 && TYPE_MAIN_VARIANT (argtype
) != TYPE_MAIN_VARIANT (target_type
)
345 && MAYBE_CLASS_TYPE_P (argtype
)
346 && MAYBE_CLASS_TYPE_P (target_type
))
348 /* We go through lookup_base for the access control. */
349 tree binfo
= lookup_base (argtype
, target_type
, ba_check
,
351 if (binfo
== error_mark_node
)
352 return error_mark_node
;
353 if (binfo
== NULL_TREE
)
354 return error_not_base_type (target_type
, argtype
);
355 rval
= build_base_path (PLUS_EXPR
, rval
, binfo
, 1, complain
);
359 = convert_to_pointer_force (build_pointer_type (target_type
),
361 return build_nop (type
, rval
);
364 /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
365 INTYPE is the original rvalue type and DECL is an optional _DECL node
368 [dcl.init.ref] says that if an rvalue is used to
369 initialize a reference, then the reference must be to a
370 non-volatile const type. */
373 diagnose_ref_binding (location_t loc
, tree reftype
, tree intype
, tree decl
)
375 tree ttl
= TREE_TYPE (reftype
);
377 if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl
))
381 if (CP_TYPE_VOLATILE_P (ttl
) && decl
)
382 msg
= G_("initialization of volatile reference type %q#T from "
383 "rvalue of type %qT");
384 else if (CP_TYPE_VOLATILE_P (ttl
))
385 msg
= G_("conversion to volatile reference type %q#T "
386 "from rvalue of type %qT");
388 msg
= G_("initialization of non-const reference type %q#T from "
389 "rvalue of type %qT");
391 msg
= G_("conversion to non-const reference type %q#T from "
392 "rvalue of type %qT");
394 permerror (loc
, msg
, reftype
, intype
);
398 /* For C++: Only need to do one-level references, but cannot
399 get tripped up on signed/unsigned differences.
401 DECL is either NULL_TREE or the _DECL node for a reference that is being
402 initialized. It can be error_mark_node if we don't know the _DECL but
403 we know it's an initialization. */
406 convert_to_reference (tree reftype
, tree expr
, int convtype
,
407 int flags
, tree decl
, tsubst_flags_t complain
)
409 tree type
= TYPE_MAIN_VARIANT (TREE_TYPE (reftype
));
411 tree rval
= NULL_TREE
;
412 tree rval_as_conversion
= NULL_TREE
;
413 bool can_convert_intype_to_type
;
414 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
416 if (TREE_CODE (type
) == FUNCTION_TYPE
417 && TREE_TYPE (expr
) == unknown_type_node
)
418 expr
= instantiate_type (type
, expr
, complain
);
420 if (expr
== error_mark_node
)
421 return error_mark_node
;
423 intype
= TREE_TYPE (expr
);
425 gcc_assert (TREE_CODE (intype
) != REFERENCE_TYPE
);
426 gcc_assert (TREE_CODE (reftype
) == REFERENCE_TYPE
);
428 intype
= TYPE_MAIN_VARIANT (intype
);
430 can_convert_intype_to_type
= can_convert_standard (type
, intype
, complain
);
432 if (!can_convert_intype_to_type
433 && (convtype
& CONV_IMPLICIT
) && MAYBE_CLASS_TYPE_P (intype
)
434 && ! (flags
& LOOKUP_NO_CONVERSION
))
436 /* Look for a user-defined conversion to lvalue that we can use. */
439 = build_type_conversion (reftype
, expr
);
441 if (rval_as_conversion
&& rval_as_conversion
!= error_mark_node
442 && real_lvalue_p (rval_as_conversion
))
444 expr
= rval_as_conversion
;
445 rval_as_conversion
= NULL_TREE
;
447 can_convert_intype_to_type
= 1;
451 if (((convtype
& CONV_STATIC
)
452 && can_convert_standard (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_error
)
460 && ! real_lvalue_p (expr
))
461 diagnose_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 && TYPE_PTR_P (intype
)
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_error
)
506 diagnose_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
= wide_int_to_tree (TREE_TYPE (expr
), expr
);
588 /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
592 cp_fold_convert (tree type
, tree expr
)
595 if (TREE_TYPE (expr
) == type
)
597 else if (TREE_CODE (expr
) == PTRMEM_CST
)
599 /* Avoid wrapping a PTRMEM_CST in NOP_EXPR. */
600 conv
= copy_node (expr
);
601 TREE_TYPE (conv
) = type
;
605 conv
= fold_convert (type
, expr
);
606 conv
= ignore_overflows (conv
, expr
);
611 /* C++ conversions, preference to static cast conversions. */
614 cp_convert (tree type
, tree expr
, tsubst_flags_t complain
)
616 return ocp_convert (type
, expr
, CONV_OLD_CONVERT
, LOOKUP_NORMAL
, complain
);
619 /* C++ equivalent of convert_and_check but using cp_convert as the
622 Convert EXPR to TYPE, warning about conversion problems with constants.
623 Invoke this function on every expression that is converted implicitly,
624 i.e. because of language rules and not because of an explicit cast. */
627 cp_convert_and_check (tree type
, tree expr
, tsubst_flags_t complain
)
631 if (TREE_TYPE (expr
) == type
)
633 if (expr
== error_mark_node
)
635 result
= cp_convert (type
, expr
, complain
);
637 if ((complain
& tf_warning
)
638 && c_inhibit_evaluation_warnings
== 0)
640 tree folded
= cp_fully_fold (expr
);
643 folded_result
= result
;
646 /* Avoid bogus -Wparentheses warnings. */
647 warning_sentinel
w (warn_parentheses
);
648 folded_result
= cp_convert (type
, folded
, tf_none
);
650 folded_result
= fold_simple (folded_result
);
651 if (!TREE_OVERFLOW_P (folded
)
652 && folded_result
!= error_mark_node
)
653 warnings_for_convert_and_check (EXPR_LOC_OR_LOC (expr
, input_location
),
654 type
, folded
, folded_result
);
662 FLAGS indicates how we should behave. */
665 ocp_convert (tree type
, tree expr
, int convtype
, int flags
,
666 tsubst_flags_t complain
)
669 enum tree_code code
= TREE_CODE (type
);
670 const char *invalid_conv_diag
;
672 location_t loc
= EXPR_LOC_OR_LOC (expr
, input_location
);
673 bool dofold
= (convtype
& CONV_FOLD
);
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 convert_to_complex_maybe_fold (type
, e
, dofold
);
711 else if (VECTOR_TYPE_P (type
))
712 return 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 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
= convert_to_integer_maybe_fold (type
, e
, dofold
);
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 cp_convert_to_pointer (type
, e
, dofold
, 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 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 convert_to_real_maybe_fold (type
, e
, dofold
);
847 else if (code
== COMPLEX_TYPE
)
848 return convert_to_complex_maybe_fold (type
, e
, dofold
);
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, don't need to destroy it, and won't abort in
1234 assign_temp. We'll still
1235 allocate space for it in expand_call or declare_return_variable,
1236 but we don't need to track it through all the tree phases. */
1237 if (TARGET_EXPR_IMPLICIT_P (expr
)
1238 && !TREE_ADDRESSABLE (TREE_TYPE (expr
)))
1240 tree init
= TARGET_EXPR_INITIAL (expr
);
1241 if (TREE_CODE (init
) == AGGR_INIT_EXPR
1242 && !AGGR_INIT_VIA_CTOR_P (init
))
1244 tree fn
= AGGR_INIT_EXPR_FN (init
);
1245 expr
= build_call_array_loc (input_location
,
1246 TREE_TYPE (TREE_TYPE (TREE_TYPE (fn
))),
1248 aggr_init_expr_nargs (init
),
1249 AGGR_INIT_EXPR_ARGP (init
));
1256 expr
= resolve_nondeduced_context (expr
, complain
);
1260 if (TREE_CODE (probe
) == ADDR_EXPR
)
1261 probe
= TREE_OPERAND (expr
, 0);
1262 if (type_unknown_p (probe
))
1264 /* [over.over] enumerates the places where we can take the address
1265 of an overloaded function, and this is not one of them. */
1266 if (complain
& tf_error
)
1270 error_at (loc
, "conversion to void "
1271 "cannot resolve address of overloaded function");
1273 case ICV_SECOND_OF_COND
:
1274 error_at (loc
, "second operand of conditional expression "
1275 "cannot resolve address of overloaded function");
1277 case ICV_THIRD_OF_COND
:
1278 error_at (loc
, "third operand of conditional expression "
1279 "cannot resolve address of overloaded function");
1281 case ICV_RIGHT_OF_COMMA
:
1282 error_at (loc
, "right operand of comma operator "
1283 "cannot resolve address of overloaded function");
1285 case ICV_LEFT_OF_COMMA
:
1286 error_at (loc
, "left operand of comma operator "
1287 "cannot resolve address of overloaded function");
1290 error_at (loc
, "statement "
1291 "cannot resolve address of overloaded function");
1293 case ICV_THIRD_IN_FOR
:
1294 error_at (loc
, "for increment expression "
1295 "cannot resolve address of overloaded function");
1299 return error_mark_node
;
1302 else if (implicit
!= ICV_CAST
&& probe
== expr
&& is_overloaded_fn (probe
))
1304 /* Only warn when there is no &. */
1305 if (complain
& tf_warning
)
1308 case ICV_SECOND_OF_COND
:
1309 warning_at (loc
, OPT_Waddress
,
1310 "second operand of conditional expression "
1311 "is a reference, not call, to function %qE", expr
);
1313 case ICV_THIRD_OF_COND
:
1314 warning_at (loc
, OPT_Waddress
,
1315 "third operand of conditional expression "
1316 "is a reference, not call, to function %qE", expr
);
1318 case ICV_RIGHT_OF_COMMA
:
1319 warning_at (loc
, OPT_Waddress
,
1320 "right operand of comma operator "
1321 "is a reference, not call, to function %qE", expr
);
1323 case ICV_LEFT_OF_COMMA
:
1324 warning_at (loc
, OPT_Waddress
,
1325 "left operand of comma operator "
1326 "is a reference, not call, to function %qE", expr
);
1329 warning_at (loc
, OPT_Waddress
,
1330 "statement is a reference, not call, to function %qE",
1333 case ICV_THIRD_IN_FOR
:
1334 warning_at (loc
, OPT_Waddress
,
1335 "for increment expression "
1336 "is a reference, not call, to function %qE", expr
);
1342 if (TREE_CODE (expr
) == COMPONENT_REF
)
1343 expr
= TREE_OPERAND (expr
, 0);
1347 if (expr
!= error_mark_node
&& !VOID_TYPE_P (TREE_TYPE (expr
)))
1349 if (implicit
!= ICV_CAST
1350 && warn_unused_value
1351 && !TREE_NO_WARNING (expr
)
1352 && !processing_template_decl
)
1354 /* The middle end does not warn about expressions that have
1355 been explicitly cast to void, so we must do so here. */
1356 if (!TREE_SIDE_EFFECTS (expr
)) {
1357 if (complain
& tf_warning
)
1360 case ICV_SECOND_OF_COND
:
1361 warning_at (loc
, OPT_Wunused_value
,
1362 "second operand of conditional expression "
1365 case ICV_THIRD_OF_COND
:
1366 warning_at (loc
, OPT_Wunused_value
,
1367 "third operand of conditional expression "
1370 case ICV_RIGHT_OF_COMMA
:
1371 warning_at (loc
, OPT_Wunused_value
,
1372 "right operand of comma operator has no effect");
1374 case ICV_LEFT_OF_COMMA
:
1375 warning_at (loc
, OPT_Wunused_value
,
1376 "left operand of comma operator has no effect");
1379 warning_at (loc
, OPT_Wunused_value
,
1380 "statement has no effect");
1382 case ICV_THIRD_IN_FOR
:
1383 warning_at (loc
, OPT_Wunused_value
,
1384 "for increment expression has no effect");
1393 enum tree_code code
;
1394 enum tree_code_class tclass
;
1397 /* We might like to warn about (say) "(int) f()", as the
1398 cast has no effect, but the compiler itself will
1399 generate implicit conversions under some
1400 circumstances. (For example a block copy will be
1401 turned into a call to "__builtin_memcpy", with a
1402 conversion of the return value to an appropriate
1403 type.) So, to avoid false positives, we strip
1404 conversions. Do not use STRIP_NOPs because it will
1405 not strip conversions to "void", as that is not a
1406 mode-preserving conversion. */
1407 while (TREE_CODE (e
) == NOP_EXPR
)
1408 e
= TREE_OPERAND (e
, 0);
1410 code
= TREE_CODE (e
);
1411 tclass
= TREE_CODE_CLASS (code
);
1412 if ((tclass
== tcc_comparison
1413 || tclass
== tcc_unary
1414 || (tclass
== tcc_binary
1415 && !(code
== MODIFY_EXPR
1416 || code
== INIT_EXPR
1417 || code
== PREDECREMENT_EXPR
1418 || code
== PREINCREMENT_EXPR
1419 || code
== POSTDECREMENT_EXPR
1420 || code
== POSTINCREMENT_EXPR
))
1421 || code
== VEC_PERM_EXPR
1422 || code
== VEC_COND_EXPR
)
1423 && (complain
& tf_warning
))
1424 warning_at (loc
, OPT_Wunused_value
, "value computed is not used");
1427 expr
= build1 (CONVERT_EXPR
, void_type_node
, expr
);
1429 if (! TREE_SIDE_EFFECTS (expr
))
1434 /* Create an expression whose value is that of EXPR,
1435 converted to type TYPE. The TREE_TYPE of the value
1436 is always TYPE. This function implements all reasonable
1437 conversions; callers should filter out those that are
1438 not permitted by the language being compiled.
1440 Most of this routine is from build_reinterpret_cast.
1442 The back end cannot call cp_convert (what was convert) because
1443 conversions to/from basetypes may involve memory references
1444 (vbases) and adding or subtracting small values (multiple
1445 inheritance), but it calls convert from the constant folding code
1446 on subtrees of already built trees after it has ripped them apart.
1448 Also, if we ever support range variables, we'll probably also have to
1449 do a little bit more work. */
1452 convert (tree type
, tree expr
)
1456 if (type
== error_mark_node
|| expr
== error_mark_node
)
1457 return error_mark_node
;
1459 intype
= TREE_TYPE (expr
);
1461 if (POINTER_TYPE_P (type
) && POINTER_TYPE_P (intype
))
1462 return build_nop (type
, expr
);
1464 return ocp_convert (type
, expr
, CONV_BACKEND_CONVERT
,
1465 LOOKUP_NORMAL
|LOOKUP_NO_CONVERSION
,
1466 tf_warning_or_error
);
1469 /* Like cp_convert, except permit conversions to take place which
1470 are not normally allowed due to access restrictions
1471 (such as conversion from sub-type to private super-type). */
1474 convert_force (tree type
, tree expr
, int convtype
, tsubst_flags_t complain
)
1477 enum tree_code code
= TREE_CODE (type
);
1479 if (code
== REFERENCE_TYPE
)
1480 return convert_to_reference (type
, e
, CONV_C_CAST
, 0,
1481 NULL_TREE
, complain
);
1483 if (code
== POINTER_TYPE
)
1484 return convert_to_pointer_force (type
, e
, complain
);
1486 /* From typeck.c convert_for_assignment */
1487 if (((TYPE_PTR_P (TREE_TYPE (e
)) && TREE_CODE (e
) == ADDR_EXPR
1488 && TREE_CODE (TREE_TYPE (TREE_TYPE (e
))) == METHOD_TYPE
)
1489 || integer_zerop (e
)
1490 || TYPE_PTRMEMFUNC_P (TREE_TYPE (e
)))
1491 && TYPE_PTRMEMFUNC_P (type
))
1492 /* compatible pointer to member functions. */
1493 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type
), e
, 1,
1494 /*c_cast_p=*/1, complain
);
1496 return ocp_convert (type
, e
, CONV_C_CAST
|convtype
, LOOKUP_NORMAL
, complain
);
1499 /* Convert an aggregate EXPR to type XTYPE. If a conversion
1500 exists, return the attempted conversion. This may
1501 return ERROR_MARK_NODE if the conversion is not
1502 allowed (references private members, etc).
1503 If no conversion exists, NULL_TREE is returned.
1505 FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1506 object parameter, or by the second standard conversion sequence if
1507 that doesn't do it. This will probably wait for an overloading rewrite.
1511 build_type_conversion (tree xtype
, tree expr
)
1513 /* C++: check to see if we can convert this aggregate type
1514 into the required type. */
1515 return build_user_type_conversion (xtype
, expr
, LOOKUP_NORMAL
,
1516 tf_warning_or_error
);
1519 /* Convert the given EXPR to one of a group of types suitable for use in an
1520 expression. DESIRES is a combination of various WANT_* flags (q.v.)
1521 which indicates which types are suitable. If COMPLAIN is true, complain
1522 about ambiguity; otherwise, the caller will deal with it. */
1525 build_expr_type_conversion (int desires
, tree expr
, bool complain
)
1527 tree basetype
= TREE_TYPE (expr
);
1528 tree conv
= NULL_TREE
;
1529 tree winner
= NULL_TREE
;
1531 if (expr
== null_node
1532 && (desires
& WANT_INT
)
1533 && !(desires
& WANT_NULL
))
1535 source_location loc
=
1536 expansion_point_location_if_in_system_header (input_location
);
1538 warning_at (loc
, OPT_Wconversion_null
,
1539 "converting NULL to non-pointer type");
1542 if (basetype
== error_mark_node
)
1543 return error_mark_node
;
1545 if (! MAYBE_CLASS_TYPE_P (basetype
))
1546 switch (TREE_CODE (basetype
))
1549 if ((desires
& WANT_NULL
) && null_ptr_cst_p (expr
))
1551 /* else fall through... */
1554 return (desires
& WANT_INT
) ? expr
: NULL_TREE
;
1556 return (desires
& WANT_ENUM
) ? expr
: NULL_TREE
;
1558 return (desires
& WANT_FLOAT
) ? expr
: NULL_TREE
;
1560 return (desires
& WANT_POINTER
) ? expr
: NULL_TREE
;
1564 return (desires
& WANT_POINTER
) ? decay_conversion (expr
,
1565 tf_warning_or_error
)
1570 if ((desires
& WANT_VECTOR_OR_COMPLEX
) == 0)
1572 switch (TREE_CODE (TREE_TYPE (basetype
)))
1576 return (desires
& WANT_INT
) ? expr
: NULL_TREE
;
1578 return (desires
& WANT_ENUM
) ? expr
: NULL_TREE
;
1580 return (desires
& WANT_FLOAT
) ? expr
: NULL_TREE
;
1589 /* The code for conversions from class type is currently only used for
1590 delete expressions. Other expressions are handled by build_new_op. */
1591 if (!complete_type_or_maybe_complain (basetype
, expr
, complain
))
1592 return error_mark_node
;
1593 if (!TYPE_HAS_CONVERSION (basetype
))
1596 for (conv
= lookup_conversions (basetype
); conv
; conv
= TREE_CHAIN (conv
))
1600 tree cand
= TREE_VALUE (conv
);
1601 cand
= OVL_CURRENT (cand
);
1603 if (winner
&& winner
== cand
)
1606 if (DECL_NONCONVERTING_P (cand
))
1609 candidate
= non_reference (TREE_TYPE (TREE_TYPE (cand
)));
1611 switch (TREE_CODE (candidate
))
1615 win
= (desires
& WANT_INT
); break;
1617 win
= (desires
& WANT_ENUM
); break;
1619 win
= (desires
& WANT_FLOAT
); break;
1621 win
= (desires
& WANT_POINTER
); break;
1625 if ((desires
& WANT_VECTOR_OR_COMPLEX
) == 0)
1627 switch (TREE_CODE (TREE_TYPE (candidate
)))
1631 win
= (desires
& WANT_INT
); break;
1633 win
= (desires
& WANT_ENUM
); break;
1635 win
= (desires
& WANT_FLOAT
); break;
1642 /* A wildcard could be instantiated to match any desired
1643 type, but we can't deduce the template argument. */
1644 if (WILDCARD_TYPE_P (candidate
))
1651 if (TREE_CODE (cand
) == TEMPLATE_DECL
)
1654 error ("default type conversion can't deduce template"
1655 " argument for %qD", cand
);
1656 return error_mark_node
;
1662 = non_reference (TREE_TYPE (TREE_TYPE (winner
)));
1664 if (!same_type_ignoring_top_level_qualifiers_p (winner_type
,
1669 error ("ambiguous default type conversion from %qT",
1671 inform (input_location
,
1672 " candidate conversions include %qD and %qD",
1675 return error_mark_node
;
1685 tree type
= non_reference (TREE_TYPE (TREE_TYPE (winner
)));
1686 return build_user_type_conversion (type
, expr
, LOOKUP_NORMAL
,
1687 tf_warning_or_error
);
1693 /* Implements integral promotion (4.1) and float->double promotion. */
1696 type_promotes_to (tree type
)
1700 if (type
== error_mark_node
)
1701 return error_mark_node
;
1703 type
= TYPE_MAIN_VARIANT (type
);
1705 /* Check for promotions of target-defined types first. */
1706 promoted_type
= targetm
.promoted_type (type
);
1708 return promoted_type
;
1710 /* bool always promotes to int (not unsigned), even if it's the same
1712 if (TREE_CODE (type
) == BOOLEAN_TYPE
)
1713 type
= integer_type_node
;
1715 /* Normally convert enums to int, but convert wide enums to something
1716 wider. Scoped enums don't promote, but pretend they do for backward
1717 ABI bug compatibility wrt varargs. */
1718 else if (TREE_CODE (type
) == ENUMERAL_TYPE
1719 || type
== char16_type_node
1720 || type
== char32_type_node
1721 || type
== wchar_type_node
)
1723 int precision
= MAX (TYPE_PRECISION (type
),
1724 TYPE_PRECISION (integer_type_node
));
1725 tree totype
= c_common_type_for_size (precision
, 0);
1727 if (TREE_CODE (prom
) == ENUMERAL_TYPE
)
1728 prom
= ENUM_UNDERLYING_TYPE (prom
);
1729 if (TYPE_UNSIGNED (prom
)
1730 && ! int_fits_type_p (TYPE_MAX_VALUE (prom
), totype
))
1731 prom
= c_common_type_for_size (precision
, 1);
1734 if (SCOPED_ENUM_P (type
))
1736 if (abi_version_crosses (6)
1737 && TYPE_MODE (prom
) != TYPE_MODE (type
))
1738 warning (OPT_Wabi
, "scoped enum %qT passed through ... as "
1739 "%qT before -fabi-version=6, %qT after",
1740 type
, prom
, ENUM_UNDERLYING_TYPE (type
));
1741 if (!abi_version_at_least (6))
1747 else if (c_promoting_integer_type_p (type
))
1749 /* Retain unsignedness if really not getting bigger. */
1750 if (TYPE_UNSIGNED (type
)
1751 && TYPE_PRECISION (type
) == TYPE_PRECISION (integer_type_node
))
1752 type
= unsigned_type_node
;
1754 type
= integer_type_node
;
1756 else if (type
== float_type_node
)
1757 type
= double_type_node
;
1762 /* The routines below this point are carefully written to conform to
1763 the standard. They use the same terminology, and follow the rules
1764 closely. Although they are used only in pt.c at the moment, they
1765 should presumably be used everywhere in the future. */
1767 /* Attempt to perform qualification conversions on EXPR to convert it
1768 to TYPE. Return the resulting expression, or error_mark_node if
1769 the conversion was impossible. */
1772 perform_qualification_conversions (tree type
, tree expr
)
1776 expr_type
= TREE_TYPE (expr
);
1778 if (same_type_p (type
, expr_type
))
1780 else if (TYPE_PTR_P (type
) && TYPE_PTR_P (expr_type
)
1781 && comp_ptr_ttypes (TREE_TYPE (type
), TREE_TYPE (expr_type
)))
1782 return build_nop (type
, expr
);
1783 else if (TYPE_PTRMEM_P (type
) && TYPE_PTRMEM_P (expr_type
)
1784 && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type
),
1785 TYPE_PTRMEM_CLASS_TYPE (expr_type
))
1786 && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type
),
1787 TYPE_PTRMEM_POINTED_TO_TYPE (expr_type
)))
1788 return build_nop (type
, expr
);
1790 return error_mark_node
;
1793 /* True iff T is a transaction-safe function type. */
1796 tx_safe_fn_type_p (tree t
)
1798 if (TREE_CODE (t
) != FUNCTION_TYPE
1799 && TREE_CODE (t
) != METHOD_TYPE
)
1801 return !!lookup_attribute ("transaction_safe", TYPE_ATTRIBUTES (t
));
1804 /* Return the transaction-unsafe variant of transaction-safe function type
1808 tx_unsafe_fn_variant (tree t
)
1810 gcc_assert (tx_safe_fn_type_p (t
));
1811 tree attrs
= remove_attribute ("transaction_safe",
1812 TYPE_ATTRIBUTES (t
));
1813 return cp_build_type_attribute_variant (t
, attrs
);
1816 /* Return true iff FROM can convert to TO by a transaction-safety
1820 can_convert_tx_safety (tree to
, tree from
)
1822 return (flag_tm
&& tx_safe_fn_type_p (from
)
1823 && same_type_p (to
, tx_unsafe_fn_variant (from
)));