1 /* Language-level data type conversion for GNU C++.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
5 Hacked by Michael Tiemann (tiemann@cygnus.com)
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
24 /* This file contains the functions for converting C++ expressions
25 to different data types. The only entry point is `convert'.
26 Every language front end must have a `convert' function
27 but what kind of conversions it does will depend on the language. */
31 #include "coretypes.h"
41 static tree
cp_convert_to_pointer (tree
, tree
);
42 static tree
convert_to_pointer_force (tree
, tree
);
43 static tree
build_type_conversion (tree
, tree
);
44 static tree
build_up_reference (tree
, tree
, int, tree
);
45 static void warn_ref_binding (tree
, tree
, tree
);
47 /* Change of width--truncation and extension of integers or reals--
48 is represented with NOP_EXPR. Proper functioning of many things
49 assumes that no other conversions can be NOP_EXPRs.
51 Conversion between integer and pointer is represented with CONVERT_EXPR.
52 Converting integer to real uses FLOAT_EXPR
53 and real to integer uses FIX_TRUNC_EXPR.
55 Here is a list of all the functions that assume that widening and
56 narrowing is always done with a NOP_EXPR:
57 In convert.c, convert_to_integer.
58 In c-typeck.c, build_binary_op_nodefault (boolean ops),
59 and c_common_truthvalue_conversion.
60 In expr.c: expand_expr, for operands of a MULT_EXPR.
61 In fold-const.c: fold.
62 In tree.c: get_narrower and get_unwidened.
64 C++: in multiple-inheritance, converting between pointers may involve
65 adjusting them by a delta stored within the class definition. */
67 /* Subroutines of `convert'. */
69 /* if converting pointer to pointer
70 if dealing with classes, check for derived->base or vice versa
71 else if dealing with method pointers, delegate
73 else if converting class, pass off to build_type_conversion
74 else try C-style pointer conversion. */
77 cp_convert_to_pointer (tree type
, tree expr
)
79 tree intype
= TREE_TYPE (expr
);
82 if (intype
== error_mark_node
)
83 return error_mark_node
;
85 if (MAYBE_CLASS_TYPE_P (intype
))
87 intype
= complete_type (intype
);
88 if (!COMPLETE_TYPE_P (intype
))
90 error ("can%'t convert from incomplete type %qT to %qT",
92 return error_mark_node
;
95 rval
= build_type_conversion (type
, expr
);
98 if (rval
== error_mark_node
)
99 error ("conversion of %qE from %qT to %qT is ambiguous",
105 /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
106 if (TREE_CODE (type
) == POINTER_TYPE
107 && (TREE_CODE (TREE_TYPE (type
)) == FUNCTION_TYPE
108 || VOID_TYPE_P (TREE_TYPE (type
))))
110 if (TYPE_PTRMEMFUNC_P (intype
)
111 || TREE_CODE (intype
) == METHOD_TYPE
)
112 return convert_member_func_to_ptr (type
, expr
);
113 if (TREE_CODE (TREE_TYPE (expr
)) == POINTER_TYPE
)
114 return build_nop (type
, expr
);
115 intype
= TREE_TYPE (expr
);
118 if (expr
== error_mark_node
)
119 return error_mark_node
;
121 form
= TREE_CODE (intype
);
123 if (POINTER_TYPE_P (intype
))
125 intype
= TYPE_MAIN_VARIANT (intype
);
127 if (TYPE_MAIN_VARIANT (type
) != intype
128 && TREE_CODE (type
) == POINTER_TYPE
129 && TREE_CODE (TREE_TYPE (type
)) == RECORD_TYPE
130 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type
))
131 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype
))
132 && TREE_CODE (TREE_TYPE (intype
)) == RECORD_TYPE
)
134 enum tree_code code
= PLUS_EXPR
;
140 intype_class
= TREE_TYPE (intype
);
141 type_class
= TREE_TYPE (type
);
143 same_p
= same_type_p (TYPE_MAIN_VARIANT (intype_class
),
144 TYPE_MAIN_VARIANT (type_class
));
146 /* Try derived to base conversion. */
148 binfo
= lookup_base (intype_class
, type_class
, ba_check
, NULL
);
149 if (!same_p
&& !binfo
)
151 /* Try base to derived conversion. */
152 binfo
= lookup_base (type_class
, intype_class
, ba_check
, NULL
);
155 if (binfo
== error_mark_node
)
156 return error_mark_node
;
160 expr
= build_base_path (code
, expr
, binfo
, 0);
161 /* Add any qualifier conversions. */
162 return build_nop (type
, expr
);
166 if (TYPE_PTRMEMFUNC_P (type
))
168 error ("cannot convert %qE from type %qT to type %qT",
170 return error_mark_node
;
173 return build_nop (type
, expr
);
175 else if ((TYPE_PTRMEM_P (type
) && TYPE_PTRMEM_P (intype
))
176 || (TYPE_PTRMEMFUNC_P (type
) && TYPE_PTRMEMFUNC_P (intype
)))
177 return convert_ptrmem (type
, expr
, /*allow_inverse_p=*/false,
178 /*c_cast_p=*/false, tf_warning_or_error
);
179 else if (TYPE_PTRMEMFUNC_P (intype
))
183 if (TREE_CODE (expr
) == PTRMEM_CST
)
184 return cp_convert_to_pointer (type
,
185 PTRMEM_CST_MEMBER (expr
));
186 else if (TREE_CODE (expr
) == OFFSET_REF
)
188 tree object
= TREE_OPERAND (expr
, 0);
189 return get_member_function_from_ptrfunc (&object
,
190 TREE_OPERAND (expr
, 1));
193 error ("cannot convert %qE from type %qT to type %qT",
195 return error_mark_node
;
198 if (null_ptr_cst_p (expr
))
200 if (TYPE_PTRMEMFUNC_P (type
))
201 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type
), expr
, 0,
202 /*c_cast_p=*/false, tf_warning_or_error
);
204 if (TYPE_PTRMEM_P (type
))
206 /* A NULL pointer-to-member is represented by -1, not by
208 expr
= build_int_cst_type (type
, -1);
211 expr
= build_int_cst (type
, 0);
215 else if (TYPE_PTR_TO_MEMBER_P (type
) && INTEGRAL_CODE_P (form
))
217 error ("invalid conversion from %qT to %qT", intype
, type
);
218 return error_mark_node
;
221 if (INTEGRAL_CODE_P (form
))
223 if (TYPE_PRECISION (intype
) == POINTER_SIZE
)
224 return build1 (CONVERT_EXPR
, type
, expr
);
225 expr
= cp_convert (c_common_type_for_size (POINTER_SIZE
, 0), expr
);
226 /* Modes may be different but sizes should be the same. There
227 is supposed to be some integral type that is the same width
229 gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr
)))
230 == GET_MODE_SIZE (TYPE_MODE (type
)));
232 return convert_to_pointer (type
, expr
);
235 if (type_unknown_p (expr
))
236 return instantiate_type (type
, expr
, tf_warning_or_error
);
238 error ("cannot convert %qE from type %qT to type %qT",
240 return error_mark_node
;
243 /* Like convert, except permit conversions to take place which
244 are not normally allowed due to access restrictions
245 (such as conversion from sub-type to private super-type). */
248 convert_to_pointer_force (tree type
, tree expr
)
250 tree intype
= TREE_TYPE (expr
);
251 enum tree_code form
= TREE_CODE (intype
);
253 if (form
== POINTER_TYPE
)
255 intype
= TYPE_MAIN_VARIANT (intype
);
257 if (TYPE_MAIN_VARIANT (type
) != intype
258 && TREE_CODE (TREE_TYPE (type
)) == RECORD_TYPE
259 && MAYBE_CLASS_TYPE_P (TREE_TYPE (type
))
260 && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype
))
261 && TREE_CODE (TREE_TYPE (intype
)) == RECORD_TYPE
)
263 enum tree_code code
= PLUS_EXPR
;
266 binfo
= lookup_base (TREE_TYPE (intype
), TREE_TYPE (type
),
270 binfo
= lookup_base (TREE_TYPE (type
), TREE_TYPE (intype
),
274 if (binfo
== error_mark_node
)
275 return error_mark_node
;
278 expr
= build_base_path (code
, expr
, binfo
, 0);
279 if (expr
== error_mark_node
)
280 return error_mark_node
;
281 /* Add any qualifier conversions. */
282 if (!same_type_p (TREE_TYPE (TREE_TYPE (expr
)),
284 expr
= build_nop (type
, expr
);
290 return cp_convert_to_pointer (type
, expr
);
293 /* We are passing something to a function which requires a reference.
294 The type we are interested in is in TYPE. The initial
295 value we have to begin with is in ARG.
297 FLAGS controls how we manage access checking.
298 DIRECT_BIND in FLAGS controls how any temporaries are generated.
299 If DIRECT_BIND is set, DECL is the reference we're binding to. */
302 build_up_reference (tree type
, tree arg
, int flags
, tree decl
)
305 tree argtype
= TREE_TYPE (arg
);
306 tree target_type
= TREE_TYPE (type
);
308 gcc_assert (TREE_CODE (type
) == REFERENCE_TYPE
);
310 if ((flags
& DIRECT_BIND
) && ! real_lvalue_p (arg
))
312 /* Create a new temporary variable. We can't just use a TARGET_EXPR
313 here because it needs to live as long as DECL. */
316 arg
= make_temporary_var_for_ref_to_temp (decl
, target_type
);
318 /* Process the initializer for the declaration. */
319 DECL_INITIAL (arg
) = targ
;
320 cp_finish_decl (arg
, targ
, /*init_const_expr_p=*/false, NULL_TREE
,
321 LOOKUP_ONLYCONVERTING
|DIRECT_BIND
);
323 else if (!(flags
& DIRECT_BIND
) && ! lvalue_p (arg
))
324 return get_target_expr (arg
);
326 /* If we had a way to wrap this up, and say, if we ever needed its
327 address, transform all occurrences of the register, into a memory
328 reference we could win better. */
329 rval
= cp_build_addr_expr (arg
, tf_warning_or_error
);
330 if (rval
== error_mark_node
)
331 return error_mark_node
;
333 if ((flags
& LOOKUP_PROTECT
)
334 && TYPE_MAIN_VARIANT (argtype
) != TYPE_MAIN_VARIANT (target_type
)
335 && MAYBE_CLASS_TYPE_P (argtype
)
336 && MAYBE_CLASS_TYPE_P (target_type
))
338 /* We go through lookup_base for the access control. */
339 tree binfo
= lookup_base (argtype
, target_type
, ba_check
, NULL
);
340 if (binfo
== error_mark_node
)
341 return error_mark_node
;
342 if (binfo
== NULL_TREE
)
343 return error_not_base_type (target_type
, argtype
);
344 rval
= build_base_path (PLUS_EXPR
, rval
, binfo
, 1);
348 = convert_to_pointer_force (build_pointer_type (target_type
), rval
);
349 return build_nop (type
, rval
);
352 /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
353 INTYPE is the original rvalue type and DECL is an optional _DECL node
356 [dcl.init.ref] says that if an rvalue is used to
357 initialize a reference, then the reference must be to a
358 non-volatile const type. */
361 warn_ref_binding (tree reftype
, tree intype
, tree decl
)
363 tree ttl
= TREE_TYPE (reftype
);
365 if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl
))
369 if (CP_TYPE_VOLATILE_P (ttl
) && decl
)
370 msg
= G_("initialization of volatile reference type %q#T from "
371 "rvalue of type %qT");
372 else if (CP_TYPE_VOLATILE_P (ttl
))
373 msg
= G_("conversion to volatile reference type %q#T "
374 "from rvalue of type %qT");
376 msg
= G_("initialization of non-const reference type %q#T from "
377 "rvalue of type %qT");
379 msg
= G_("conversion to non-const reference type %q#T from "
380 "rvalue of type %qT");
382 permerror (input_location
, msg
, reftype
, intype
);
386 /* For C++: Only need to do one-level references, but cannot
387 get tripped up on signed/unsigned differences.
389 DECL is either NULL_TREE or the _DECL node for a reference that is being
390 initialized. It can be error_mark_node if we don't know the _DECL but
391 we know it's an initialization. */
394 convert_to_reference (tree reftype
, tree expr
, int convtype
,
395 int flags
, tree decl
)
397 tree type
= TYPE_MAIN_VARIANT (TREE_TYPE (reftype
));
399 tree rval
= NULL_TREE
;
400 tree rval_as_conversion
= NULL_TREE
;
401 bool can_convert_intype_to_type
;
403 if (TREE_CODE (type
) == FUNCTION_TYPE
404 && TREE_TYPE (expr
) == unknown_type_node
)
405 expr
= instantiate_type (type
, expr
,
406 (flags
& LOOKUP_COMPLAIN
)
407 ? tf_warning_or_error
: tf_none
);
409 if (expr
== error_mark_node
)
410 return error_mark_node
;
412 intype
= TREE_TYPE (expr
);
414 gcc_assert (TREE_CODE (intype
) != REFERENCE_TYPE
);
415 gcc_assert (TREE_CODE (reftype
) == REFERENCE_TYPE
);
417 intype
= TYPE_MAIN_VARIANT (intype
);
419 can_convert_intype_to_type
= can_convert (type
, intype
);
420 if (!can_convert_intype_to_type
421 && (convtype
& CONV_IMPLICIT
) && MAYBE_CLASS_TYPE_P (intype
)
422 && ! (flags
& LOOKUP_NO_CONVERSION
))
424 /* Look for a user-defined conversion to lvalue that we can use. */
427 = build_type_conversion (reftype
, expr
);
429 if (rval_as_conversion
&& rval_as_conversion
!= error_mark_node
430 && real_lvalue_p (rval_as_conversion
))
432 expr
= rval_as_conversion
;
433 rval_as_conversion
= NULL_TREE
;
435 can_convert_intype_to_type
= 1;
439 if (((convtype
& CONV_STATIC
) && can_convert (intype
, type
))
440 || ((convtype
& CONV_IMPLICIT
) && can_convert_intype_to_type
))
442 if (flags
& LOOKUP_COMPLAIN
)
444 tree ttl
= TREE_TYPE (reftype
);
445 tree ttr
= lvalue_type (expr
);
447 if (! real_lvalue_p (expr
))
448 warn_ref_binding (reftype
, intype
, decl
);
450 if (! (convtype
& CONV_CONST
)
451 && !at_least_as_qualified_p (ttl
, ttr
))
452 permerror (input_location
, "conversion from %qT to %qT discards qualifiers",
456 return build_up_reference (reftype
, expr
, flags
, decl
);
458 else if ((convtype
& CONV_REINTERPRET
) && lvalue_p (expr
))
460 /* When casting an lvalue to a reference type, just convert into
461 a pointer to the new type and deference it. This is allowed
462 by San Diego WP section 5.2.9 paragraph 12, though perhaps it
463 should be done directly (jason). (int &)ri ---> *(int*)&ri */
465 /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
467 if (TREE_CODE (intype
) == POINTER_TYPE
468 && (comptypes (TREE_TYPE (intype
), type
,
469 COMPARE_BASE
| COMPARE_DERIVED
)))
470 warning (0, "casting %qT to %qT does not dereference pointer",
473 rval
= cp_build_addr_expr (expr
, tf_warning_or_error
);
474 if (rval
!= error_mark_node
)
475 rval
= convert_force (build_pointer_type (TREE_TYPE (reftype
)),
477 if (rval
!= error_mark_node
)
478 rval
= build1 (NOP_EXPR
, reftype
, rval
);
482 rval
= convert_for_initialization (NULL_TREE
, type
, expr
, flags
,
483 ICR_CONVERTING
, 0, 0,
484 tf_warning_or_error
);
485 if (rval
== NULL_TREE
|| rval
== error_mark_node
)
487 warn_ref_binding (reftype
, intype
, decl
);
488 rval
= build_up_reference (reftype
, rval
, flags
, decl
);
493 /* If we found a way to convert earlier, then use it. */
497 if (flags
& LOOKUP_COMPLAIN
)
498 error ("cannot convert type %qT to type %qT", intype
, reftype
);
500 return error_mark_node
;
503 /* We are using a reference VAL for its value. Bash that reference all the
504 way down to its lowest form. */
507 convert_from_reference (tree val
)
510 && TREE_CODE (TREE_TYPE (val
)) == REFERENCE_TYPE
)
512 tree t
= TREE_TYPE (TREE_TYPE (val
));
513 tree ref
= build1 (INDIRECT_REF
, t
, val
);
515 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
516 so that we get the proper error message if the result is used
517 to assign to. Also, &* is supposed to be a no-op. */
518 TREE_READONLY (ref
) = CP_TYPE_CONST_P (t
);
519 TREE_THIS_VOLATILE (ref
) = CP_TYPE_VOLATILE_P (t
);
520 TREE_SIDE_EFFECTS (ref
)
521 = (TREE_THIS_VOLATILE (ref
) || TREE_SIDE_EFFECTS (val
));
522 REFERENCE_REF_P (ref
) = 1;
529 /* Really perform an lvalue-to-rvalue conversion, including copying an
530 argument of class type into a temporary. */
533 force_rvalue (tree expr
)
535 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (expr
)) && TREE_CODE (expr
) != TARGET_EXPR
)
536 expr
= ocp_convert (TREE_TYPE (expr
), expr
,
537 CONV_IMPLICIT
|CONV_FORCE_TEMP
, LOOKUP_NORMAL
);
539 expr
= decay_conversion (expr
);
545 /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has
546 TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR
550 ignore_overflows (tree expr
, tree orig
)
552 if (TREE_CODE (expr
) == INTEGER_CST
553 && TREE_CODE (orig
) == INTEGER_CST
554 && TREE_OVERFLOW (expr
) != TREE_OVERFLOW (orig
))
556 gcc_assert (!TREE_OVERFLOW (orig
));
557 /* Ensure constant sharing. */
558 expr
= build_int_cst_wide (TREE_TYPE (expr
),
559 TREE_INT_CST_LOW (expr
),
560 TREE_INT_CST_HIGH (expr
));
565 /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
569 cp_fold_convert (tree type
, tree expr
)
571 tree conv
= fold_convert (type
, expr
);
572 conv
= ignore_overflows (conv
, expr
);
576 /* C++ conversions, preference to static cast conversions. */
579 cp_convert (tree type
, tree expr
)
581 return ocp_convert (type
, expr
, CONV_OLD_CONVERT
, LOOKUP_NORMAL
);
584 /* C++ equivalent of convert_and_check but using cp_convert as the
587 Convert EXPR to TYPE, warning about conversion problems with constants.
588 Invoke this function on every expression that is converted implicitly,
589 i.e. because of language rules and not because of an explicit cast. */
592 cp_convert_and_check (tree type
, tree expr
)
596 if (TREE_TYPE (expr
) == type
)
599 result
= cp_convert (type
, expr
);
601 if (c_inhibit_evaluation_warnings
== 0
602 && !TREE_OVERFLOW_P (expr
)
603 && result
!= error_mark_node
)
604 warnings_for_convert_and_check (type
, expr
, result
);
611 FLAGS indicates how we should behave. */
614 ocp_convert (tree type
, tree expr
, int convtype
, int flags
)
617 enum tree_code code
= TREE_CODE (type
);
618 const char *invalid_conv_diag
;
621 if (error_operand_p (e
) || type
== error_mark_node
)
622 return error_mark_node
;
624 complete_type (type
);
625 complete_type (TREE_TYPE (expr
));
627 if ((invalid_conv_diag
628 = targetm
.invalid_conversion (TREE_TYPE (expr
), type
)))
630 error (invalid_conv_diag
);
631 return error_mark_node
;
634 /* FIXME remove when moving to c_fully_fold model. */
635 /* FIXME do we still need this test? */
636 if (!CLASS_TYPE_P (type
))
637 e
= integral_constant_value (e
);
638 if (error_operand_p (e
))
639 return error_mark_node
;
641 if (MAYBE_CLASS_TYPE_P (type
) && (convtype
& CONV_FORCE_TEMP
))
642 /* We need a new temporary; don't take this shortcut. */;
643 else if (same_type_ignoring_top_level_qualifiers_p (type
, TREE_TYPE (e
)))
645 if (same_type_p (type
, TREE_TYPE (e
)))
646 /* The call to fold will not always remove the NOP_EXPR as
647 might be expected, since if one of the types is a typedef;
648 the comparison in fold is just equality of pointers, not a
649 call to comptypes. We don't call fold in this case because
650 that can result in infinite recursion; fold will call
651 convert, which will call ocp_convert, etc. */
653 /* For complex data types, we need to perform componentwise
655 else if (TREE_CODE (type
) == COMPLEX_TYPE
)
656 return fold_if_not_in_template (convert_to_complex (type
, e
));
657 else if (TREE_CODE (e
) == TARGET_EXPR
)
659 /* Don't build a NOP_EXPR of class type. Instead, change the
660 type of the temporary. */
661 TREE_TYPE (e
) = TREE_TYPE (TARGET_EXPR_SLOT (e
)) = type
;
666 /* We shouldn't be treating objects of ADDRESSABLE type as
668 gcc_assert (!TREE_ADDRESSABLE (type
));
669 return fold_if_not_in_template (build_nop (type
, e
));
673 e1
= targetm
.convert_to_type (type
, e
);
677 if (code
== VOID_TYPE
&& (convtype
& CONV_STATIC
))
679 e
= convert_to_void (e
, ICV_CAST
, tf_warning_or_error
);
683 if (INTEGRAL_CODE_P (code
))
685 tree intype
= TREE_TYPE (e
);
688 if (TREE_CODE (type
) == ENUMERAL_TYPE
)
690 /* enum = enum, enum = int, enum = float, (enum)pointer are all
692 if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype
)
693 || TREE_CODE (intype
) == REAL_TYPE
)
694 && ! (convtype
& CONV_STATIC
))
695 || TREE_CODE (intype
) == POINTER_TYPE
)
697 if (flags
& LOOKUP_COMPLAIN
)
698 permerror (input_location
, "conversion from %q#T to %q#T", intype
, type
);
700 if (!flag_permissive
)
701 return error_mark_node
;
704 /* [expr.static.cast]
706 8. A value of integral or enumeration type can be explicitly
707 converted to an enumeration type. The value is unchanged if
708 the original value is within the range of the enumeration
709 values. Otherwise, the resulting enumeration value is
711 if (TREE_CODE (expr
) == INTEGER_CST
712 && !int_fits_type_p (expr
, ENUM_UNDERLYING_TYPE (type
)))
713 warning (OPT_Wconversion
,
714 "the result of the conversion is unspecified because "
715 "%qE is outside the range of type %qT",
718 if (MAYBE_CLASS_TYPE_P (intype
))
721 rval
= build_type_conversion (type
, e
);
724 if (flags
& LOOKUP_COMPLAIN
)
725 error ("%q#T used where a %qT was expected", intype
, type
);
726 return error_mark_node
;
728 if (code
== BOOLEAN_TYPE
)
729 return cp_truthvalue_conversion (e
);
731 converted
= fold_if_not_in_template (convert_to_integer (type
, e
));
733 /* Ignore any integer overflow caused by the conversion. */
734 return ignore_overflows (converted
, e
);
736 if (NULLPTR_TYPE_P (type
) && e
&& null_ptr_cst_p (e
))
738 if (POINTER_TYPE_P (type
) || TYPE_PTR_TO_MEMBER_P (type
))
739 return fold_if_not_in_template (cp_convert_to_pointer (type
, e
));
740 if (code
== VECTOR_TYPE
)
742 tree in_vtype
= TREE_TYPE (e
);
743 if (MAYBE_CLASS_TYPE_P (in_vtype
))
746 ret_val
= build_type_conversion (type
, e
);
749 if (flags
& LOOKUP_COMPLAIN
)
750 error ("%q#T used where a %qT was expected", in_vtype
, type
);
751 return error_mark_node
;
753 return fold_if_not_in_template (convert_to_vector (type
, e
));
755 if (code
== REAL_TYPE
|| code
== COMPLEX_TYPE
)
757 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e
)))
760 rval
= build_type_conversion (type
, e
);
764 if (flags
& LOOKUP_COMPLAIN
)
765 error ("%q#T used where a floating point value was expected",
768 if (code
== REAL_TYPE
)
769 return fold_if_not_in_template (convert_to_real (type
, e
));
770 else if (code
== COMPLEX_TYPE
)
771 return fold_if_not_in_template (convert_to_complex (type
, e
));
774 /* New C++ semantics: since assignment is now based on
775 memberwise copying, if the rhs type is derived from the
776 lhs type, then we may still do a conversion. */
777 if (RECORD_OR_UNION_CODE_P (code
))
779 tree dtype
= TREE_TYPE (e
);
780 tree ctor
= NULL_TREE
;
782 dtype
= TYPE_MAIN_VARIANT (dtype
);
784 /* Conversion between aggregate types. New C++ semantics allow
785 objects of derived type to be cast to objects of base type.
786 Old semantics only allowed this between pointers.
788 There may be some ambiguity between using a constructor
789 vs. using a type conversion operator when both apply. */
793 if (abstract_virtuals_error (NULL_TREE
, type
))
794 return error_mark_node
;
796 if (BRACE_ENCLOSED_INITIALIZER_P (ctor
))
797 ctor
= perform_implicit_conversion (type
, ctor
, tf_warning_or_error
);
798 else if ((flags
& LOOKUP_ONLYCONVERTING
)
799 && ! (CLASS_TYPE_P (dtype
) && DERIVED_FROM_P (type
, dtype
)))
800 /* For copy-initialization, first we create a temp of the proper type
801 with a user-defined conversion sequence, then we direct-initialize
802 the target with the temp (see [dcl.init]). */
803 ctor
= build_user_type_conversion (type
, ctor
, flags
);
806 VEC(tree
,gc
) *ctor_vec
= make_tree_vector_single (ctor
);
807 ctor
= build_special_member_call (NULL_TREE
,
808 complete_ctor_identifier
,
811 tf_warning_or_error
);
812 release_tree_vector (ctor_vec
);
815 return build_cplus_new (type
, ctor
);
818 if (flags
& LOOKUP_COMPLAIN
)
820 /* If the conversion failed and expr was an invalid use of pointer to
821 member function, try to report a meaningful error. */
822 if (invalid_nonstatic_memfn_p (expr
, tf_warning_or_error
))
823 /* We displayed the error message. */;
825 error ("conversion from %qT to non-scalar type %qT requested",
826 TREE_TYPE (expr
), type
);
828 return error_mark_node
;
831 /* When an expression is used in a void context, its value is discarded and
832 no lvalue-rvalue and similar conversions happen [expr.static.cast/4,
833 stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type
834 in a void context. The C++ standard does not define what an `access' to an
835 object is, but there is reason to believe that it is the lvalue to rvalue
836 conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it
837 accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8
838 indicates that volatile semantics should be the same between C and C++
839 where ever possible. C leaves it implementation defined as to what
840 constitutes an access to a volatile. So, we interpret `*vp' as a read of
841 the volatile object `vp' points to, unless that is an incomplete type. For
842 volatile references we do not do this interpretation, because that would
843 make it impossible to ignore the reference return value from functions. We
844 issue warnings in the confusing cases.
846 The IMPLICIT is ICV_CAST when the user is explicitly converting an expression
847 to void via a cast. If an expression is being implicitly converted, IMPLICIT
848 indicates the context of the implicit conversion. */
851 convert_to_void (tree expr
, impl_conv_void implicit
, tsubst_flags_t complain
)
853 if (expr
== error_mark_node
854 || TREE_TYPE (expr
) == error_mark_node
)
855 return error_mark_node
;
857 if (implicit
== ICV_CAST
)
858 mark_exp_read (expr
);
863 while (TREE_CODE (exprv
) == COMPOUND_EXPR
)
864 exprv
= TREE_OPERAND (exprv
, 1);
866 || handled_component_p (exprv
)
867 || TREE_CODE (exprv
) == INDIRECT_REF
)
868 /* Expr is not being 'used' here, otherwise we whould have
869 called mark_{rl}value_use use here, which would have in turn
870 called mark_exp_read. Rather, we call mark_exp_read directly
871 to avoid some warnings when
872 -Wunused-but-set-{variable,parameter} is in effect. */
873 mark_exp_read (exprv
);
876 if (!TREE_TYPE (expr
))
878 if (invalid_nonstatic_memfn_p (expr
, complain
))
879 return error_mark_node
;
880 if (TREE_CODE (expr
) == PSEUDO_DTOR_EXPR
)
882 if (complain
& tf_error
)
883 error ("pseudo-destructor is not called");
884 return error_mark_node
;
886 if (VOID_TYPE_P (TREE_TYPE (expr
)))
888 switch (TREE_CODE (expr
))
892 /* The two parts of a cond expr might be separate lvalues. */
893 tree op1
= TREE_OPERAND (expr
,1);
894 tree op2
= TREE_OPERAND (expr
,2);
895 bool side_effects
= TREE_SIDE_EFFECTS (op1
) || TREE_SIDE_EFFECTS (op2
);
896 tree new_op1
, new_op2
;
897 if (implicit
!= ICV_CAST
&& !side_effects
)
899 new_op1
= convert_to_void (op1
, ICV_SECOND_OF_COND
, complain
);
900 new_op2
= convert_to_void (op2
, ICV_THIRD_OF_COND
, complain
);
904 new_op1
= convert_to_void (op1
, ICV_CAST
, complain
);
905 new_op2
= convert_to_void (op2
, ICV_CAST
, complain
);
908 expr
= build3 (COND_EXPR
, TREE_TYPE (new_op1
),
909 TREE_OPERAND (expr
, 0), new_op1
, new_op2
);
915 /* The second part of a compound expr contains the value. */
916 tree op1
= TREE_OPERAND (expr
,1);
918 if (implicit
!= ICV_CAST
&& !TREE_NO_WARNING (expr
))
919 new_op1
= convert_to_void (op1
, ICV_RIGHT_OF_COMMA
, complain
);
921 new_op1
= convert_to_void (op1
, ICV_CAST
, complain
);
925 tree t
= build2 (COMPOUND_EXPR
, TREE_TYPE (new_op1
),
926 TREE_OPERAND (expr
, 0), new_op1
);
933 case NON_LVALUE_EXPR
:
935 /* These have already decayed to rvalue. */
938 case CALL_EXPR
: /* We have a special meaning for volatile void fn(). */
943 tree type
= TREE_TYPE (expr
);
944 int is_reference
= TREE_CODE (TREE_TYPE (TREE_OPERAND (expr
, 0)))
946 int is_volatile
= TYPE_VOLATILE (type
);
947 int is_complete
= COMPLETE_TYPE_P (complete_type (type
));
949 /* Can't load the value if we don't know the type. */
950 if (is_volatile
&& !is_complete
)
952 if (complain
& tf_warning
)
956 warning (0, "conversion to void will not access "
957 "object of incomplete type %qT", type
);
959 case ICV_SECOND_OF_COND
:
960 warning (0, "indirection will not access object of "
961 "incomplete type %qT in second operand "
962 "of conditional expression", type
);
964 case ICV_THIRD_OF_COND
:
965 warning (0, "indirection will not access object of "
966 "incomplete type %qT in third operand "
967 "of conditional expression", type
);
969 case ICV_RIGHT_OF_COMMA
:
970 warning (0, "indirection will not access object of "
971 "incomplete type %qT in right operand of "
972 "comma operator", type
);
974 case ICV_LEFT_OF_COMMA
:
975 warning (0, "indirection will not access object of "
976 "incomplete type %qT in left operand of "
977 "comma operator", type
);
980 warning (0, "indirection will not access object of "
981 "incomplete type %qT in statement", type
);
983 case ICV_THIRD_IN_FOR
:
984 warning (0, "indirection will not access object of "
985 "incomplete type %qT in for increment "
992 /* Don't load the value if this is an implicit dereference, or if
993 the type needs to be handled by ctors/dtors. */
994 else if (is_volatile
&& is_reference
)
996 if (complain
& tf_warning
)
1000 warning (0, "conversion to void will not access "
1001 "object of type %qT", type
);
1003 case ICV_SECOND_OF_COND
:
1004 warning (0, "implicit dereference will not access object "
1005 "of type %qT in second operand of "
1006 "conditional expression", type
);
1008 case ICV_THIRD_OF_COND
:
1009 warning (0, "implicit dereference will not access object "
1010 "of type %qT in third operand of "
1011 "conditional expression", type
);
1013 case ICV_RIGHT_OF_COMMA
:
1014 warning (0, "implicit dereference will not access object "
1015 "of type %qT in right operand of "
1016 "comma operator", type
);
1018 case ICV_LEFT_OF_COMMA
:
1019 warning (0, "implicit dereference will not access object "
1020 "of type %qT in left operand of comma operator",
1024 warning (0, "implicit dereference will not access object "
1025 "of type %qT in statement", type
);
1027 case ICV_THIRD_IN_FOR
:
1028 warning (0, "implicit dereference will not access object "
1029 "of type %qT in for increment expression",
1036 else if (is_volatile
&& TREE_ADDRESSABLE (type
))
1038 if (complain
& tf_warning
)
1042 warning (0, "conversion to void will not access "
1043 "object of non-trivially-copyable type %qT",
1046 case ICV_SECOND_OF_COND
:
1047 warning (0, "indirection will not access object of "
1048 "non-trivially-copyable type %qT in second "
1049 "operand of conditional expression", type
);
1051 case ICV_THIRD_OF_COND
:
1052 warning (0, "indirection will not access object of "
1053 "non-trivially-copyable type %qT in third "
1054 "operand of conditional expression", type
);
1056 case ICV_RIGHT_OF_COMMA
:
1057 warning (0, "indirection will not access object of "
1058 "non-trivially-copyable type %qT in right "
1059 "operand of comma operator", type
);
1061 case ICV_LEFT_OF_COMMA
:
1062 warning (0, "indirection will not access object of "
1063 "non-trivially-copyable type %qT in left "
1064 "operand of comma operator", type
);
1067 warning (0, "indirection will not access object of "
1068 "non-trivially-copyable type %qT in statement",
1071 case ICV_THIRD_IN_FOR
:
1072 warning (0, "indirection will not access object of "
1073 "non-trivially-copyable type %qT in for "
1074 "increment expression", type
);
1080 if (is_reference
|| !is_volatile
|| !is_complete
|| TREE_ADDRESSABLE (type
))
1082 /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
1083 operation is stripped off. Note that we don't warn about
1084 - an expression with TREE_NO_WARNING set. (For an example of
1085 such expressions, see build_over_call in call.c.)
1086 - automatic dereferencing of references, since the user cannot
1087 control it. (See also warn_if_unused_value() in stmt.c.) */
1088 if (warn_unused_value
1089 && implicit
!= ICV_CAST
1090 && (complain
& tf_warning
)
1091 && !TREE_NO_WARNING (expr
)
1093 warning (OPT_Wunused_value
, "value computed is not used");
1094 expr
= TREE_OPERAND (expr
, 0);
1102 /* External variables might be incomplete. */
1103 tree type
= TREE_TYPE (expr
);
1104 int is_complete
= COMPLETE_TYPE_P (complete_type (type
));
1106 if (TYPE_VOLATILE (type
) && !is_complete
&& (complain
& tf_warning
))
1110 warning (0, "conversion to void will not access "
1111 "object %qE of incomplete type %qT", expr
, type
);
1113 case ICV_SECOND_OF_COND
:
1114 warning (0, "variable %qE of incomplete type %qT will not "
1115 "be accessed in second operand of "
1116 "conditional expression", expr
, type
);
1118 case ICV_THIRD_OF_COND
:
1119 warning (0, "variable %qE of incomplete type %qT will not "
1120 "be accessed in third operand of "
1121 "conditional expression", expr
, type
);
1123 case ICV_RIGHT_OF_COMMA
:
1124 warning (0, "variable %qE of incomplete type %qT will not "
1125 "be accessed in right operand of comma operator",
1128 case ICV_LEFT_OF_COMMA
:
1129 warning (0, "variable %qE of incomplete type %qT will not "
1130 "be accessed in left operand of comma operator",
1134 warning (0, "variable %qE of incomplete type %qT will not "
1135 "be accessed in statement", expr
, type
);
1137 case ICV_THIRD_IN_FOR
:
1138 warning (0, "variable %qE of incomplete type %qT will not "
1139 "be accessed in for increment expression",
1150 /* Don't bother with the temporary object returned from a function if
1151 we don't use it and don't need to destroy it. We'll still
1152 allocate space for it in expand_call or declare_return_variable,
1153 but we don't need to track it through all the tree phases. */
1154 if (TARGET_EXPR_IMPLICIT_P (expr
)
1155 && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr
)))
1157 tree init
= TARGET_EXPR_INITIAL (expr
);
1158 if (TREE_CODE (init
) == AGGR_INIT_EXPR
1159 && !AGGR_INIT_VIA_CTOR_P (init
))
1161 tree fn
= AGGR_INIT_EXPR_FN (init
);
1162 expr
= build_call_array_loc (input_location
,
1163 TREE_TYPE (TREE_TYPE (TREE_TYPE (fn
))),
1165 aggr_init_expr_nargs (init
),
1166 AGGR_INIT_EXPR_ARGP (init
));
1173 expr
= resolve_nondeduced_context (expr
);
1177 if (TREE_CODE (probe
) == ADDR_EXPR
)
1178 probe
= TREE_OPERAND (expr
, 0);
1179 if (type_unknown_p (probe
))
1181 /* [over.over] enumerates the places where we can take the address
1182 of an overloaded function, and this is not one of them. */
1183 if (complain
& tf_error
)
1187 error ("conversion to void "
1188 "cannot resolve address of overloaded function");
1190 case ICV_SECOND_OF_COND
:
1191 error ("second operand of conditional expression "
1192 "cannot resolve address of overloaded function");
1194 case ICV_THIRD_OF_COND
:
1195 error ("third operand of conditional expression "
1196 "cannot resolve address of overloaded function");
1198 case ICV_RIGHT_OF_COMMA
:
1199 error ("right operand of comma operator "
1200 "cannot resolve address of overloaded function");
1202 case ICV_LEFT_OF_COMMA
:
1203 error ("left operand of comma operator "
1204 "cannot resolve address of overloaded function");
1208 "cannot resolve address of overloaded function");
1210 case ICV_THIRD_IN_FOR
:
1211 error ("for increment expression "
1212 "cannot resolve address of overloaded function");
1216 return error_mark_node
;
1217 expr
= void_zero_node
;
1219 else if (implicit
!= ICV_CAST
&& probe
== expr
&& is_overloaded_fn (probe
))
1221 /* Only warn when there is no &. */
1222 if (complain
& tf_warning
)
1225 case ICV_SECOND_OF_COND
:
1226 warning (OPT_Waddress
,
1227 "second operand of conditional expression "
1228 "is a reference, not call, to function %qE", expr
);
1230 case ICV_THIRD_OF_COND
:
1231 warning (OPT_Waddress
,
1232 "third operand of conditional expression "
1233 "is a reference, not call, to function %qE", expr
);
1235 case ICV_RIGHT_OF_COMMA
:
1236 warning (OPT_Waddress
,
1237 "right operand of comma operator "
1238 "is a reference, not call, to function %qE", expr
);
1240 case ICV_LEFT_OF_COMMA
:
1241 warning (OPT_Waddress
,
1242 "left operand of comma operator "
1243 "is a reference, not call, to function %qE", expr
);
1246 warning (OPT_Waddress
,
1247 "statement is a reference, not call, to function %qE",
1250 case ICV_THIRD_IN_FOR
:
1251 warning (OPT_Waddress
,
1252 "for increment expression "
1253 "is a reference, not call, to function %qE", expr
);
1259 if (TREE_CODE (expr
) == COMPONENT_REF
)
1260 expr
= TREE_OPERAND (expr
, 0);
1264 if (expr
!= error_mark_node
&& !VOID_TYPE_P (TREE_TYPE (expr
)))
1266 if (implicit
!= ICV_CAST
1267 && warn_unused_value
1268 && !TREE_NO_WARNING (expr
)
1269 && !processing_template_decl
)
1271 /* The middle end does not warn about expressions that have
1272 been explicitly cast to void, so we must do so here. */
1273 if (!TREE_SIDE_EFFECTS (expr
)) {
1274 if (complain
& tf_warning
)
1277 case ICV_SECOND_OF_COND
:
1278 warning (OPT_Wunused_value
,
1279 "second operand of conditional expression has no effect");
1281 case ICV_THIRD_OF_COND
:
1282 warning (OPT_Wunused_value
,
1283 "third operand of conditional expression has no effect");
1285 case ICV_RIGHT_OF_COMMA
:
1286 warning (OPT_Wunused_value
,
1287 "right operand of comma operator has no effect");
1289 case ICV_LEFT_OF_COMMA
:
1290 warning (OPT_Wunused_value
,
1291 "left operand of comma operator has no effect");
1294 warning (OPT_Wunused_value
,
1295 "statement has no effect");
1297 case ICV_THIRD_IN_FOR
:
1298 warning (OPT_Wunused_value
,
1299 "for increment expression has no effect");
1308 enum tree_code code
;
1309 enum tree_code_class tclass
;
1312 /* We might like to warn about (say) "(int) f()", as the
1313 cast has no effect, but the compiler itself will
1314 generate implicit conversions under some
1315 circumstances. (For example a block copy will be
1316 turned into a call to "__builtin_memcpy", with a
1317 conversion of the return value to an appropriate
1318 type.) So, to avoid false positives, we strip
1319 conversions. Do not use STRIP_NOPs because it will
1320 not strip conversions to "void", as that is not a
1321 mode-preserving conversion. */
1322 while (TREE_CODE (e
) == NOP_EXPR
)
1323 e
= TREE_OPERAND (e
, 0);
1325 code
= TREE_CODE (e
);
1326 tclass
= TREE_CODE_CLASS (code
);
1327 if ((tclass
== tcc_comparison
1328 || tclass
== tcc_unary
1329 || (tclass
== tcc_binary
1330 && !(code
== MODIFY_EXPR
1331 || code
== INIT_EXPR
1332 || code
== PREDECREMENT_EXPR
1333 || code
== PREINCREMENT_EXPR
1334 || code
== POSTDECREMENT_EXPR
1335 || code
== POSTINCREMENT_EXPR
)))
1336 && (complain
& tf_warning
))
1337 warning (OPT_Wunused_value
, "value computed is not used");
1340 expr
= build1 (CONVERT_EXPR
, void_type_node
, expr
);
1342 if (! TREE_SIDE_EFFECTS (expr
))
1343 expr
= void_zero_node
;
1347 /* Create an expression whose value is that of EXPR,
1348 converted to type TYPE. The TREE_TYPE of the value
1349 is always TYPE. This function implements all reasonable
1350 conversions; callers should filter out those that are
1351 not permitted by the language being compiled.
1353 Most of this routine is from build_reinterpret_cast.
1355 The back end cannot call cp_convert (what was convert) because
1356 conversions to/from basetypes may involve memory references
1357 (vbases) and adding or subtracting small values (multiple
1358 inheritance), but it calls convert from the constant folding code
1359 on subtrees of already built trees after it has ripped them apart.
1361 Also, if we ever support range variables, we'll probably also have to
1362 do a little bit more work. */
1365 convert (tree type
, tree expr
)
1369 if (type
== error_mark_node
|| expr
== error_mark_node
)
1370 return error_mark_node
;
1372 intype
= TREE_TYPE (expr
);
1374 if (POINTER_TYPE_P (type
) && POINTER_TYPE_P (intype
))
1375 return fold_if_not_in_template (build_nop (type
, expr
));
1377 return ocp_convert (type
, expr
, CONV_OLD_CONVERT
,
1378 LOOKUP_NORMAL
|LOOKUP_NO_CONVERSION
);
1381 /* Like cp_convert, except permit conversions to take place which
1382 are not normally allowed due to access restrictions
1383 (such as conversion from sub-type to private super-type). */
1386 convert_force (tree type
, tree expr
, int convtype
)
1389 enum tree_code code
= TREE_CODE (type
);
1391 if (code
== REFERENCE_TYPE
)
1392 return (fold_if_not_in_template
1393 (convert_to_reference (type
, e
, CONV_C_CAST
, LOOKUP_COMPLAIN
,
1396 if (code
== POINTER_TYPE
)
1397 return fold_if_not_in_template (convert_to_pointer_force (type
, e
));
1399 /* From typeck.c convert_for_assignment */
1400 if (((TREE_CODE (TREE_TYPE (e
)) == POINTER_TYPE
&& TREE_CODE (e
) == ADDR_EXPR
1401 && TREE_CODE (TREE_TYPE (e
)) == POINTER_TYPE
1402 && TREE_CODE (TREE_TYPE (TREE_TYPE (e
))) == METHOD_TYPE
)
1403 || integer_zerop (e
)
1404 || TYPE_PTRMEMFUNC_P (TREE_TYPE (e
)))
1405 && TYPE_PTRMEMFUNC_P (type
))
1406 /* compatible pointer to member functions. */
1407 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type
), e
, 1,
1408 /*c_cast_p=*/1, tf_warning_or_error
);
1410 return ocp_convert (type
, e
, CONV_C_CAST
|convtype
, LOOKUP_NORMAL
);
1413 /* Convert an aggregate EXPR to type XTYPE. If a conversion
1414 exists, return the attempted conversion. This may
1415 return ERROR_MARK_NODE if the conversion is not
1416 allowed (references private members, etc).
1417 If no conversion exists, NULL_TREE is returned.
1419 FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1420 object parameter, or by the second standard conversion sequence if
1421 that doesn't do it. This will probably wait for an overloading rewrite.
1425 build_type_conversion (tree xtype
, tree expr
)
1427 /* C++: check to see if we can convert this aggregate type
1428 into the required type. */
1429 return build_user_type_conversion (xtype
, expr
, LOOKUP_NORMAL
);
1432 /* Convert the given EXPR to one of a group of types suitable for use in an
1433 expression. DESIRES is a combination of various WANT_* flags (q.v.)
1434 which indicates which types are suitable. If COMPLAIN is true, complain
1435 about ambiguity; otherwise, the caller will deal with it. */
1438 build_expr_type_conversion (int desires
, tree expr
, bool complain
)
1440 tree basetype
= TREE_TYPE (expr
);
1441 tree conv
= NULL_TREE
;
1442 tree winner
= NULL_TREE
;
1444 if (expr
== null_node
1445 && (desires
& WANT_INT
)
1446 && !(desires
& WANT_NULL
))
1447 warning_at (input_location
, OPT_Wconversion_null
,
1448 "converting NULL to non-pointer type");
1450 basetype
= TREE_TYPE (expr
);
1452 if (basetype
== error_mark_node
)
1453 return error_mark_node
;
1455 if (! MAYBE_CLASS_TYPE_P (basetype
))
1456 switch (TREE_CODE (basetype
))
1459 if ((desires
& WANT_NULL
) && null_ptr_cst_p (expr
))
1461 /* else fall through... */
1464 return (desires
& WANT_INT
) ? expr
: NULL_TREE
;
1466 return (desires
& WANT_ENUM
) ? expr
: NULL_TREE
;
1468 return (desires
& WANT_FLOAT
) ? expr
: NULL_TREE
;
1470 return (desires
& WANT_POINTER
) ? expr
: NULL_TREE
;
1474 return (desires
& WANT_POINTER
) ? decay_conversion (expr
)
1479 if ((desires
& WANT_VECTOR_OR_COMPLEX
) == 0)
1481 switch (TREE_CODE (TREE_TYPE (basetype
)))
1485 return (desires
& WANT_INT
) ? expr
: NULL_TREE
;
1487 return (desires
& WANT_ENUM
) ? expr
: NULL_TREE
;
1489 return (desires
& WANT_FLOAT
) ? expr
: NULL_TREE
;
1498 /* The code for conversions from class type is currently only used for
1499 delete expressions. Other expressions are handled by build_new_op. */
1500 if (!complete_type_or_maybe_complain (basetype
, expr
, complain
))
1501 return error_mark_node
;
1502 if (!TYPE_HAS_CONVERSION (basetype
))
1505 for (conv
= lookup_conversions (basetype
); conv
; conv
= TREE_CHAIN (conv
))
1509 tree cand
= TREE_VALUE (conv
);
1510 cand
= OVL_CURRENT (cand
);
1512 if (winner
&& winner
== cand
)
1515 if (DECL_NONCONVERTING_P (cand
))
1518 candidate
= non_reference (TREE_TYPE (TREE_TYPE (cand
)));
1520 switch (TREE_CODE (candidate
))
1524 win
= (desires
& WANT_INT
); break;
1526 win
= (desires
& WANT_ENUM
); break;
1528 win
= (desires
& WANT_FLOAT
); break;
1530 win
= (desires
& WANT_POINTER
); break;
1534 if ((desires
& WANT_VECTOR_OR_COMPLEX
) == 0)
1536 switch (TREE_CODE (TREE_TYPE (candidate
)))
1540 win
= (desires
& WANT_INT
); break;
1542 win
= (desires
& WANT_ENUM
); break;
1544 win
= (desires
& WANT_FLOAT
); break;
1560 error ("ambiguous default type conversion from %qT",
1562 error (" candidate conversions include %qD and %qD",
1565 return error_mark_node
;
1574 tree type
= non_reference (TREE_TYPE (TREE_TYPE (winner
)));
1575 return build_user_type_conversion (type
, expr
, LOOKUP_NORMAL
);
1581 /* Implements integral promotion (4.1) and float->double promotion. */
1584 type_promotes_to (tree type
)
1588 if (type
== error_mark_node
)
1589 return error_mark_node
;
1591 type
= TYPE_MAIN_VARIANT (type
);
1593 /* Check for promotions of target-defined types first. */
1594 promoted_type
= targetm
.promoted_type (type
);
1596 return promoted_type
;
1598 /* bool always promotes to int (not unsigned), even if it's the same
1600 if (TREE_CODE (type
) == BOOLEAN_TYPE
)
1601 type
= integer_type_node
;
1603 /* Normally convert enums to int, but convert wide enums to something
1605 else if (TREE_CODE (type
) == ENUMERAL_TYPE
1606 || type
== char16_type_node
1607 || type
== char32_type_node
1608 || type
== wchar_type_node
)
1610 int precision
= MAX (TYPE_PRECISION (type
),
1611 TYPE_PRECISION (integer_type_node
));
1612 tree totype
= c_common_type_for_size (precision
, 0);
1613 if (TREE_CODE (type
) == ENUMERAL_TYPE
)
1614 type
= ENUM_UNDERLYING_TYPE (type
);
1615 if (TYPE_UNSIGNED (type
)
1616 && ! int_fits_type_p (TYPE_MAX_VALUE (type
), totype
))
1617 type
= c_common_type_for_size (precision
, 1);
1621 else if (c_promoting_integer_type_p (type
))
1623 /* Retain unsignedness if really not getting bigger. */
1624 if (TYPE_UNSIGNED (type
)
1625 && TYPE_PRECISION (type
) == TYPE_PRECISION (integer_type_node
))
1626 type
= unsigned_type_node
;
1628 type
= integer_type_node
;
1630 else if (type
== float_type_node
)
1631 type
= double_type_node
;
1636 /* The routines below this point are carefully written to conform to
1637 the standard. They use the same terminology, and follow the rules
1638 closely. Although they are used only in pt.c at the moment, they
1639 should presumably be used everywhere in the future. */
1641 /* Attempt to perform qualification conversions on EXPR to convert it
1642 to TYPE. Return the resulting expression, or error_mark_node if
1643 the conversion was impossible. */
1646 perform_qualification_conversions (tree type
, tree expr
)
1650 expr_type
= TREE_TYPE (expr
);
1652 if (same_type_p (type
, expr_type
))
1654 else if (TYPE_PTR_P (type
) && TYPE_PTR_P (expr_type
)
1655 && comp_ptr_ttypes (TREE_TYPE (type
), TREE_TYPE (expr_type
)))
1656 return build_nop (type
, expr
);
1657 else if (TYPE_PTR_TO_MEMBER_P (type
)
1658 && TYPE_PTR_TO_MEMBER_P (expr_type
)
1659 && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type
),
1660 TYPE_PTRMEM_CLASS_TYPE (expr_type
))
1661 && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type
),
1662 TYPE_PTRMEM_POINTED_TO_TYPE (expr_type
)))
1663 return build_nop (type
, expr
);
1665 return error_mark_node
;