1 /* Build expressions with type checking for C++ compiler.
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
4 Hacked by Michael Tiemann (tiemann@cygnus.com)
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
11 any later version.
12
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
22
23
24 /* This file is part of the C++ front end.
25 It contains routines to build C++ expressions given their operands,
26 including computing the types of the result, C and C++ specific error
27 checks, and some optimization.
28
29 There are also routines to build RETURN_STMT nodes and CASE_STMT nodes,
30 and to process initializations in declarations (since they work
31 like a strange sort of assignment). */
32
33 #include "config.h"
34 #include "system.h"
35 #include "coretypes.h"
36 #include "tm.h"
37 #include "tree.h"
38 #include "rtl.h"
39 #include "expr.h"
40 #include "cp-tree.h"
41 #include "tm_p.h"
42 #include "flags.h"
43 #include "output.h"
44 #include "toplev.h"
45 #include "diagnostic.h"
46 #include "target.h"
47 #include "convert.h"
48
49 static tree convert_for_assignment (tree, tree, const char *, tree, int);
50 static tree cp_pointer_int_sum (enum tree_code, tree, tree);
51 static tree rationalize_conditional_expr (enum tree_code, tree);
52 static int comp_ptr_ttypes_real (tree, tree, int);
53 static int comp_ptr_ttypes_const (tree, tree);
54 static bool comp_except_types (tree, tree, bool);
55 static bool comp_array_types (tree, tree, bool);
56 static tree common_base_type (tree, tree);
57 static tree pointer_diff (tree, tree, tree);
58 static tree get_delta_difference (tree, tree, int);
59 static void casts_away_constness_r (tree *, tree *);
60 static bool casts_away_constness (tree, tree);
61 static void maybe_warn_about_returning_address_of_local (tree);
62 static tree lookup_destructor (tree, tree, tree);
63
64 /* Return the target type of TYPE, which means return T for:
65 T*, T&, T[], T (...), and otherwise, just T. */
66
67 tree
target_type(tree type)68 target_type (tree type)
69 {
70 type = non_reference (type);
71 while (TREE_CODE (type) == POINTER_TYPE
72 || TREE_CODE (type) == ARRAY_TYPE
73 || TREE_CODE (type) == FUNCTION_TYPE
74 || TREE_CODE (type) == METHOD_TYPE
75 || TYPE_PTRMEM_P (type))
76 type = TREE_TYPE (type);
77 return type;
78 }
79
80 /* Do `exp = require_complete_type (exp);' to make sure exp
81 does not have an incomplete type. (That includes void types.)
82 Returns the error_mark_node if the VALUE does not have
83 complete type when this function returns. */
84
85 tree
require_complete_type(tree value)86 require_complete_type (tree value)
87 {
88 tree type;
89
90 if (processing_template_decl || value == error_mark_node)
91 return value;
92
93 if (TREE_CODE (value) == OVERLOAD)
94 type = unknown_type_node;
95 else
96 type = TREE_TYPE (value);
97
98 /* First, detect a valid value with a complete type. */
99 if (COMPLETE_TYPE_P (type))
100 return value;
101
102 if (complete_type_or_else (type, value))
103 return value;
104 else
105 return error_mark_node;
106 }
107
108 /* Try to complete TYPE, if it is incomplete. For example, if TYPE is
109 a template instantiation, do the instantiation. Returns TYPE,
110 whether or not it could be completed, unless something goes
111 horribly wrong, in which case the error_mark_node is returned. */
112
113 tree
complete_type(tree type)114 complete_type (tree type)
115 {
116 if (type == NULL_TREE)
117 /* Rather than crash, we return something sure to cause an error
118 at some point. */
119 return error_mark_node;
120
121 if (type == error_mark_node || COMPLETE_TYPE_P (type))
122 ;
123 else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
124 {
125 tree t = complete_type (TREE_TYPE (type));
126 if (COMPLETE_TYPE_P (t) && !dependent_type_p (type))
127 layout_type (type);
128 TYPE_NEEDS_CONSTRUCTING (type)
129 = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (t));
130 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type)
131 = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (t));
132 }
133 else if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type))
134 instantiate_class_template (TYPE_MAIN_VARIANT (type));
135
136 return type;
137 }
138
139 /* Like complete_type, but issue an error if the TYPE cannot be completed.
140 VALUE is used for informative diagnostics. DIAG_TYPE indicates the type
141 of diagnostic: 0 for an error, 1 for a warning, 2 for a pedwarn.
142 Returns NULL_TREE if the type cannot be made complete. */
143
144 tree
complete_type_or_diagnostic(tree type,tree value,int diag_type)145 complete_type_or_diagnostic (tree type, tree value, int diag_type)
146 {
147 type = complete_type (type);
148 if (type == error_mark_node)
149 /* We already issued an error. */
150 return NULL_TREE;
151 else if (!COMPLETE_TYPE_P (type))
152 {
153 cxx_incomplete_type_diagnostic (value, type, diag_type);
154 return NULL_TREE;
155 }
156 else
157 return type;
158 }
159
160 /* Return truthvalue of whether type of EXP is instantiated. */
161
162 int
type_unknown_p(tree exp)163 type_unknown_p (tree exp)
164 {
165 return (TREE_CODE (exp) == TREE_LIST
166 || TREE_TYPE (exp) == unknown_type_node);
167 }
168
169
170 /* Return the common type of two parameter lists.
171 We assume that comptypes has already been done and returned 1;
172 if that isn't so, this may crash.
173
174 As an optimization, free the space we allocate if the parameter
175 lists are already common. */
176
177 tree
commonparms(tree p1,tree p2)178 commonparms (tree p1, tree p2)
179 {
180 tree oldargs = p1, newargs, n;
181 int i, len;
182 int any_change = 0;
183
184 len = list_length (p1);
185 newargs = tree_last (p1);
186
187 if (newargs == void_list_node)
188 i = 1;
189 else
190 {
191 i = 0;
192 newargs = 0;
193 }
194
195 for (; i < len; i++)
196 newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
197
198 n = newargs;
199
200 for (i = 0; p1;
201 p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n), i++)
202 {
203 if (TREE_PURPOSE (p1) && !TREE_PURPOSE (p2))
204 {
205 TREE_PURPOSE (n) = TREE_PURPOSE (p1);
206 any_change = 1;
207 }
208 else if (! TREE_PURPOSE (p1))
209 {
210 if (TREE_PURPOSE (p2))
211 {
212 TREE_PURPOSE (n) = TREE_PURPOSE (p2);
213 any_change = 1;
214 }
215 }
216 else
217 {
218 if (1 != simple_cst_equal (TREE_PURPOSE (p1), TREE_PURPOSE (p2)))
219 any_change = 1;
220 TREE_PURPOSE (n) = TREE_PURPOSE (p2);
221 }
222 if (TREE_VALUE (p1) != TREE_VALUE (p2))
223 {
224 any_change = 1;
225 TREE_VALUE (n) = merge_types (TREE_VALUE (p1), TREE_VALUE (p2));
226 }
227 else
228 TREE_VALUE (n) = TREE_VALUE (p1);
229 }
230 if (! any_change)
231 return oldargs;
232
233 return newargs;
234 }
235
236 /* Given a type, perhaps copied for a typedef,
237 find the "original" version of it. */
238 tree
original_type(tree t)239 original_type (tree t)
240 {
241 while (TYPE_NAME (t) != NULL_TREE)
242 {
243 tree x = TYPE_NAME (t);
244 if (TREE_CODE (x) != TYPE_DECL)
245 break;
246 x = DECL_ORIGINAL_TYPE (x);
247 if (x == NULL_TREE)
248 break;
249 t = x;
250 }
251 return t;
252 }
253
254 /* T1 and T2 are arithmetic or enumeration types. Return the type
255 that will result from the "usual arithmetic conversions" on T1 and
256 T2 as described in [expr]. */
257
258 tree
type_after_usual_arithmetic_conversions(tree t1,tree t2)259 type_after_usual_arithmetic_conversions (tree t1, tree t2)
260 {
261 enum tree_code code1 = TREE_CODE (t1);
262 enum tree_code code2 = TREE_CODE (t2);
263 tree attributes;
264
265 /* FIXME: Attributes. */
266 my_friendly_assert (ARITHMETIC_TYPE_P (t1)
267 || TREE_CODE (t1) == COMPLEX_TYPE
268 || TREE_CODE (t1) == ENUMERAL_TYPE,
269 19990725);
270 my_friendly_assert (ARITHMETIC_TYPE_P (t2)
271 || TREE_CODE (t2) == COMPLEX_TYPE
272 || TREE_CODE (t2) == ENUMERAL_TYPE,
273 19990725);
274
275 /* In what follows, we slightly generalize the rules given in [expr] so
276 as to deal with `long long' and `complex'. First, merge the
277 attributes. */
278 attributes = (*targetm.merge_type_attributes) (t1, t2);
279
280 /* If one type is complex, form the common type of the non-complex
281 components, then make that complex. Use T1 or T2 if it is the
282 required type. */
283 if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
284 {
285 tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
286 tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
287 tree subtype
288 = type_after_usual_arithmetic_conversions (subtype1, subtype2);
289
290 if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
291 return build_type_attribute_variant (t1, attributes);
292 else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
293 return build_type_attribute_variant (t2, attributes);
294 else
295 return build_type_attribute_variant (build_complex_type (subtype),
296 attributes);
297 }
298
299 /* If only one is real, use it as the result. */
300 if (code1 == REAL_TYPE && code2 != REAL_TYPE)
301 return build_type_attribute_variant (t1, attributes);
302 if (code2 == REAL_TYPE && code1 != REAL_TYPE)
303 return build_type_attribute_variant (t2, attributes);
304
305 /* Perform the integral promotions. */
306 if (code1 != REAL_TYPE)
307 {
308 t1 = type_promotes_to (t1);
309 t2 = type_promotes_to (t2);
310 }
311
312 /* Both real or both integers; use the one with greater precision. */
313 if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
314 return build_type_attribute_variant (t1, attributes);
315 else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
316 return build_type_attribute_variant (t2, attributes);
317
318 /* The types are the same; no need to do anything fancy. */
319 if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
320 return build_type_attribute_variant (t1, attributes);
321
322 if (code1 != REAL_TYPE)
323 {
324 /* If one is a sizetype, use it so size_binop doesn't blow up. */
325 if (TYPE_IS_SIZETYPE (t1) > TYPE_IS_SIZETYPE (t2))
326 return build_type_attribute_variant (t1, attributes);
327 if (TYPE_IS_SIZETYPE (t2) > TYPE_IS_SIZETYPE (t1))
328 return build_type_attribute_variant (t2, attributes);
329
330 /* If one is unsigned long long, then convert the other to unsigned
331 long long. */
332 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_unsigned_type_node)
333 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_unsigned_type_node))
334 return build_type_attribute_variant (long_long_unsigned_type_node,
335 attributes);
336 /* If one is a long long, and the other is an unsigned long, and
337 long long can represent all the values of an unsigned long, then
338 convert to a long long. Otherwise, convert to an unsigned long
339 long. Otherwise, if either operand is long long, convert the
340 other to long long.
341
342 Since we're here, we know the TYPE_PRECISION is the same;
343 therefore converting to long long cannot represent all the values
344 of an unsigned long, so we choose unsigned long long in that
345 case. */
346 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_integer_type_node)
347 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_integer_type_node))
348 {
349 tree t = ((TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2))
350 ? long_long_unsigned_type_node
351 : long_long_integer_type_node);
352 return build_type_attribute_variant (t, attributes);
353 }
354
355 /* Go through the same procedure, but for longs. */
356 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_unsigned_type_node)
357 || same_type_p (TYPE_MAIN_VARIANT (t2), long_unsigned_type_node))
358 return build_type_attribute_variant (long_unsigned_type_node,
359 attributes);
360 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_integer_type_node)
361 || same_type_p (TYPE_MAIN_VARIANT (t2), long_integer_type_node))
362 {
363 tree t = ((TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2))
364 ? long_unsigned_type_node : long_integer_type_node);
365 return build_type_attribute_variant (t, attributes);
366 }
367 /* Otherwise prefer the unsigned one. */
368 if (TREE_UNSIGNED (t1))
369 return build_type_attribute_variant (t1, attributes);
370 else
371 return build_type_attribute_variant (t2, attributes);
372 }
373 else
374 {
375 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_double_type_node)
376 || same_type_p (TYPE_MAIN_VARIANT (t2), long_double_type_node))
377 return build_type_attribute_variant (long_double_type_node,
378 attributes);
379 if (same_type_p (TYPE_MAIN_VARIANT (t1), double_type_node)
380 || same_type_p (TYPE_MAIN_VARIANT (t2), double_type_node))
381 return build_type_attribute_variant (double_type_node,
382 attributes);
383 if (same_type_p (TYPE_MAIN_VARIANT (t1), float_type_node)
384 || same_type_p (TYPE_MAIN_VARIANT (t2), float_type_node))
385 return build_type_attribute_variant (float_type_node,
386 attributes);
387
388 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of
389 the standard C++ floating-point types. Logic earlier in this
390 function has already eliminated the possibility that
391 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no
392 compelling reason to choose one or the other. */
393 return build_type_attribute_variant (t1, attributes);
394 }
395 }
396
397 /* Subroutine of composite_pointer_type to implement the recursive
398 case. See that function for documentation fo the parameters. */
399
400 static tree
composite_pointer_type_r(tree t1,tree t2,const char * location)401 composite_pointer_type_r (tree t1, tree t2, const char* location)
402 {
403 tree pointee1;
404 tree pointee2;
405 tree result_type;
406 tree attributes;
407
408 /* Determine the types pointed to by T1 and T2. */
409 if (TREE_CODE (t1) == POINTER_TYPE)
410 {
411 pointee1 = TREE_TYPE (t1);
412 pointee2 = TREE_TYPE (t2);
413 }
414 else
415 {
416 pointee1 = TYPE_PTRMEM_POINTED_TO_TYPE (t1);
417 pointee2 = TYPE_PTRMEM_POINTED_TO_TYPE (t2);
418 }
419
420 /* [expr.rel]
421
422 Otherwise, the composite pointer type is a pointer type
423 similar (_conv.qual_) to the type of one of the operands,
424 with a cv-qualification signature (_conv.qual_) that is the
425 union of the cv-qualification signatures of the operand
426 types. */
427 if (same_type_ignoring_top_level_qualifiers_p (pointee1, pointee2))
428 result_type = pointee1;
429 else if ((TREE_CODE (pointee1) == POINTER_TYPE
430 && TREE_CODE (pointee2) == POINTER_TYPE)
431 || (TYPE_PTR_TO_MEMBER_P (pointee1)
432 && TYPE_PTR_TO_MEMBER_P (pointee2)))
433 result_type = composite_pointer_type_r (pointee1, pointee2, location);
434 else
435 {
436 pedwarn ("%s between distinct pointer types `%T' and `%T' "
437 "lacks a cast",
438 location, t1, t2);
439 result_type = void_type_node;
440 }
441 result_type = cp_build_qualified_type (result_type,
442 (cp_type_quals (pointee1)
443 | cp_type_quals (pointee2)));
444 /* If the original types were pointers to members, so is the
445 result. */
446 if (TYPE_PTR_TO_MEMBER_P (t1))
447 {
448 if (!same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1),
449 TYPE_PTRMEM_CLASS_TYPE (t2)))
450 pedwarn ("%s between distinct pointer types `%T' and `%T' "
451 "lacks a cast",
452 location, t1, t2);
453 result_type = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1),
454 result_type);
455 }
456 else
457 result_type = build_pointer_type (result_type);
458
459 /* Merge the attributes. */
460 attributes = (*targetm.merge_type_attributes) (t1, t2);
461 return build_type_attribute_variant (result_type, attributes);
462 }
463
464 /* Return the composite pointer type (see [expr.rel]) for T1 and T2.
465 ARG1 and ARG2 are the values with those types. The LOCATION is a
466 string describing the current location, in case an error occurs.
467
468 This routine also implements the computation of a common type for
469 pointers-to-members as per [expr.eq]. */
470
471 tree
composite_pointer_type(tree t1,tree t2,tree arg1,tree arg2,const char * location)472 composite_pointer_type (tree t1, tree t2, tree arg1, tree arg2,
473 const char* location)
474 {
475 tree class1;
476 tree class2;
477
478 /* [expr.rel]
479
480 If one operand is a null pointer constant, the composite pointer
481 type is the type of the other operand. */
482 if (null_ptr_cst_p (arg1))
483 return t2;
484 if (null_ptr_cst_p (arg2))
485 return t1;
486
487 /* We have:
488
489 [expr.rel]
490
491 If one of the operands has type "pointer to cv1 void*", then
492 the other has type "pointer to cv2T", and the composite pointer
493 type is "pointer to cv12 void", where cv12 is the union of cv1
494 and cv2.
495
496 If either type is a pointer to void, make sure it is T1. */
497 if (TREE_CODE (t2) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t2)))
498 {
499 tree t;
500 t = t1;
501 t1 = t2;
502 t2 = t;
503 }
504
505 /* Now, if T1 is a pointer to void, merge the qualifiers. */
506 if (TREE_CODE (t1) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t1)))
507 {
508 tree attributes;
509 tree result_type;
510
511 if (pedantic && TYPE_PTRFN_P (t2))
512 pedwarn ("ISO C++ forbids %s between pointer of type `void *' and pointer-to-function", location);
513 result_type
514 = cp_build_qualified_type (void_type_node,
515 (cp_type_quals (TREE_TYPE (t1))
516 | cp_type_quals (TREE_TYPE (t2))));
517 result_type = build_pointer_type (result_type);
518 /* Merge the attributes. */
519 attributes = (*targetm.merge_type_attributes) (t1, t2);
520 return build_type_attribute_variant (result_type, attributes);
521 }
522
523 /* [expr.eq] permits the application of a pointer conversion to
524 bring the pointers to a common type. */
525 if (TREE_CODE (t1) == POINTER_TYPE && TREE_CODE (t2) == POINTER_TYPE
526 && CLASS_TYPE_P (TREE_TYPE (t1))
527 && CLASS_TYPE_P (TREE_TYPE (t2))
528 && !same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (t1),
529 TREE_TYPE (t2)))
530 {
531 class1 = TREE_TYPE (t1);
532 class2 = TREE_TYPE (t2);
533
534 if (DERIVED_FROM_P (class1, class2))
535 t2 = (build_pointer_type
536 (cp_build_qualified_type (class1, TYPE_QUALS (class2))));
537 else if (DERIVED_FROM_P (class2, class1))
538 t1 = (build_pointer_type
539 (cp_build_qualified_type (class2, TYPE_QUALS (class1))));
540 else
541 {
542 error ("%s between distinct pointer types `%T' and `%T' "
543 "lacks a cast", location, t1, t2);
544 return error_mark_node;
545 }
546 }
547 /* [expr.eq] permits the application of a pointer-to-member
548 conversion to change the class type of one of the types. */
549 else if (TYPE_PTR_TO_MEMBER_P (t1)
550 && !same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1),
551 TYPE_PTRMEM_CLASS_TYPE (t2)))
552 {
553 class1 = TYPE_PTRMEM_CLASS_TYPE (t1);
554 class2 = TYPE_PTRMEM_CLASS_TYPE (t2);
555
556 if (DERIVED_FROM_P (class1, class2))
557 t1 = build_ptrmem_type (class2, TYPE_PTRMEM_POINTED_TO_TYPE (t1));
558 else if (DERIVED_FROM_P (class2, class1))
559 t2 = build_ptrmem_type (class1, TYPE_PTRMEM_POINTED_TO_TYPE (t2));
560 else
561 {
562 error ("%s between distinct pointer-to-member types `%T' and `%T' "
563 "lacks a cast", location, t1, t2);
564 return error_mark_node;
565 }
566 }
567
568 return composite_pointer_type_r (t1, t2, location);
569 }
570
571 /* Return the merged type of two types.
572 We assume that comptypes has already been done and returned 1;
573 if that isn't so, this may crash.
574
575 This just combines attributes and default arguments; any other
576 differences would cause the two types to compare unalike. */
577
578 tree
merge_types(tree t1,tree t2)579 merge_types (tree t1, tree t2)
580 {
581 enum tree_code code1;
582 enum tree_code code2;
583 tree attributes;
584
585 /* Save time if the two types are the same. */
586 if (t1 == t2)
587 return t1;
588 if (original_type (t1) == original_type (t2))
589 return t1;
590
591 /* If one type is nonsense, use the other. */
592 if (t1 == error_mark_node)
593 return t2;
594 if (t2 == error_mark_node)
595 return t1;
596
597 /* Merge the attributes. */
598 attributes = (*targetm.merge_type_attributes) (t1, t2);
599
600 if (TYPE_PTRMEMFUNC_P (t1))
601 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1);
602 if (TYPE_PTRMEMFUNC_P (t2))
603 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2);
604
605 code1 = TREE_CODE (t1);
606 code2 = TREE_CODE (t2);
607
608 switch (code1)
609 {
610 case POINTER_TYPE:
611 case REFERENCE_TYPE:
612 /* For two pointers, do this recursively on the target type. */
613 {
614 tree target = merge_types (TREE_TYPE (t1), TREE_TYPE (t2));
615 int quals = cp_type_quals (t1);
616
617 if (code1 == POINTER_TYPE)
618 t1 = build_pointer_type (target);
619 else
620 t1 = build_reference_type (target);
621 t1 = build_type_attribute_variant (t1, attributes);
622 t1 = cp_build_qualified_type (t1, quals);
623
624 if (TREE_CODE (target) == METHOD_TYPE)
625 t1 = build_ptrmemfunc_type (t1);
626
627 return t1;
628 }
629
630 case OFFSET_TYPE:
631 {
632 int quals;
633 tree pointee;
634 quals = cp_type_quals (t1);
635 pointee = merge_types (TYPE_PTRMEM_POINTED_TO_TYPE (t1),
636 TYPE_PTRMEM_POINTED_TO_TYPE (t2));
637 t1 = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1),
638 pointee);
639 t1 = cp_build_qualified_type (t1, quals);
640 break;
641 }
642
643 case ARRAY_TYPE:
644 {
645 tree elt = merge_types (TREE_TYPE (t1), TREE_TYPE (t2));
646 /* Save space: see if the result is identical to one of the args. */
647 if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
648 return build_type_attribute_variant (t1, attributes);
649 if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
650 return build_type_attribute_variant (t2, attributes);
651 /* Merge the element types, and have a size if either arg has one. */
652 t1 = build_cplus_array_type
653 (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
654 break;
655 }
656
657 case FUNCTION_TYPE:
658 /* Function types: prefer the one that specified arg types.
659 If both do, merge the arg types. Also merge the return types. */
660 {
661 tree valtype = merge_types (TREE_TYPE (t1), TREE_TYPE (t2));
662 tree p1 = TYPE_ARG_TYPES (t1);
663 tree p2 = TYPE_ARG_TYPES (t2);
664 tree rval, raises;
665
666 /* Save space: see if the result is identical to one of the args. */
667 if (valtype == TREE_TYPE (t1) && ! p2)
668 return cp_build_type_attribute_variant (t1, attributes);
669 if (valtype == TREE_TYPE (t2) && ! p1)
670 return cp_build_type_attribute_variant (t2, attributes);
671
672 /* Simple way if one arg fails to specify argument types. */
673 if (p1 == NULL_TREE || TREE_VALUE (p1) == void_type_node)
674 {
675 rval = build_function_type (valtype, p2);
676 if ((raises = TYPE_RAISES_EXCEPTIONS (t2)))
677 rval = build_exception_variant (rval, raises);
678 return cp_build_type_attribute_variant (rval, attributes);
679 }
680 raises = TYPE_RAISES_EXCEPTIONS (t1);
681 if (p2 == NULL_TREE || TREE_VALUE (p2) == void_type_node)
682 {
683 rval = build_function_type (valtype, p1);
684 if (raises)
685 rval = build_exception_variant (rval, raises);
686 return cp_build_type_attribute_variant (rval, attributes);
687 }
688
689 rval = build_function_type (valtype, commonparms (p1, p2));
690 t1 = build_exception_variant (rval, raises);
691 break;
692 }
693
694 case METHOD_TYPE:
695 {
696 /* Get this value the long way, since TYPE_METHOD_BASETYPE
697 is just the main variant of this. */
698 tree basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t2)));
699 tree raises = TYPE_RAISES_EXCEPTIONS (t1);
700 tree t3;
701
702 /* If this was a member function type, get back to the
703 original type of type member function (i.e., without
704 the class instance variable up front. */
705 t1 = build_function_type (TREE_TYPE (t1),
706 TREE_CHAIN (TYPE_ARG_TYPES (t1)));
707 t2 = build_function_type (TREE_TYPE (t2),
708 TREE_CHAIN (TYPE_ARG_TYPES (t2)));
709 t3 = merge_types (t1, t2);
710 t3 = build_method_type_directly (basetype, TREE_TYPE (t3),
711 TYPE_ARG_TYPES (t3));
712 t1 = build_exception_variant (t3, raises);
713 break;
714 }
715
716 case TYPENAME_TYPE:
717 /* There is no need to merge attributes into a TYPENAME_TYPE.
718 When the type is instantiated it will have whatever
719 attributes result from the instantiation. */
720 return t1;
721
722 default:;
723 }
724 return cp_build_type_attribute_variant (t1, attributes);
725 }
726
727 /* Return the common type of two types.
728 We assume that comptypes has already been done and returned 1;
729 if that isn't so, this may crash.
730
731 This is the type for the result of most arithmetic operations
732 if the operands have the given two types. */
733
734 tree
common_type(tree t1,tree t2)735 common_type (tree t1, tree t2)
736 {
737 enum tree_code code1;
738 enum tree_code code2;
739
740 /* If one type is nonsense, bail. */
741 if (t1 == error_mark_node || t2 == error_mark_node)
742 return error_mark_node;
743
744 code1 = TREE_CODE (t1);
745 code2 = TREE_CODE (t2);
746
747 if ((ARITHMETIC_TYPE_P (t1) || code1 == ENUMERAL_TYPE
748 || code1 == COMPLEX_TYPE)
749 && (ARITHMETIC_TYPE_P (t2) || code2 == ENUMERAL_TYPE
750 || code2 == COMPLEX_TYPE))
751 return type_after_usual_arithmetic_conversions (t1, t2);
752
753 else if ((TYPE_PTR_P (t1) && TYPE_PTR_P (t2))
754 || (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2))
755 || (TYPE_PTRMEMFUNC_P (t1) && TYPE_PTRMEMFUNC_P (t2)))
756 return composite_pointer_type (t1, t2, error_mark_node, error_mark_node,
757 "conversion");
758 else
759 abort ();
760 }
761
762 /* Compare two exception specifier types for exactness or subsetness, if
763 allowed. Returns false for mismatch, true for match (same, or
764 derived and !exact).
765
766 [except.spec] "If a class X ... objects of class X or any class publicly
767 and unambiguously derived from X. Similarly, if a pointer type Y * ...
768 exceptions of type Y * or that are pointers to any type publicly and
769 unambiguously derived from Y. Otherwise a function only allows exceptions
770 that have the same type ..."
771 This does not mention cv qualifiers and is different to what throw
772 [except.throw] and catch [except.catch] will do. They will ignore the
773 top level cv qualifiers, and allow qualifiers in the pointer to class
774 example.
775
776 We implement the letter of the standard. */
777
778 static bool
comp_except_types(tree a,tree b,bool exact)779 comp_except_types (tree a, tree b, bool exact)
780 {
781 if (same_type_p (a, b))
782 return true;
783 else if (!exact)
784 {
785 if (cp_type_quals (a) || cp_type_quals (b))
786 return false;
787
788 if (TREE_CODE (a) == POINTER_TYPE
789 && TREE_CODE (b) == POINTER_TYPE)
790 {
791 a = TREE_TYPE (a);
792 b = TREE_TYPE (b);
793 if (cp_type_quals (a) || cp_type_quals (b))
794 return false;
795 }
796
797 if (TREE_CODE (a) != RECORD_TYPE
798 || TREE_CODE (b) != RECORD_TYPE)
799 return false;
800
801 if (ACCESSIBLY_UNIQUELY_DERIVED_P (a, b))
802 return true;
803 }
804 return false;
805 }
806
807 /* Return true if TYPE1 and TYPE2 are equivalent exception specifiers.
808 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7),
809 otherwise it must be exact. Exception lists are unordered, but
810 we've already filtered out duplicates. Most lists will be in order,
811 we should try to make use of that. */
812
813 bool
comp_except_specs(tree t1,tree t2,bool exact)814 comp_except_specs (tree t1, tree t2, bool exact)
815 {
816 tree probe;
817 tree base;
818 int length = 0;
819
820 if (t1 == t2)
821 return true;
822
823 if (t1 == NULL_TREE) /* T1 is ... */
824 return t2 == NULL_TREE || !exact;
825 if (!TREE_VALUE (t1)) /* t1 is EMPTY */
826 return t2 != NULL_TREE && !TREE_VALUE (t2);
827 if (t2 == NULL_TREE) /* T2 is ... */
828 return false;
829 if (TREE_VALUE (t1) && !TREE_VALUE (t2)) /* T2 is EMPTY, T1 is not */
830 return !exact;
831
832 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1.
833 Count how many we find, to determine exactness. For exact matching and
834 ordered T1, T2, this is an O(n) operation, otherwise its worst case is
835 O(nm). */
836 for (base = t1; t2 != NULL_TREE; t2 = TREE_CHAIN (t2))
837 {
838 for (probe = base; probe != NULL_TREE; probe = TREE_CHAIN (probe))
839 {
840 tree a = TREE_VALUE (probe);
841 tree b = TREE_VALUE (t2);
842
843 if (comp_except_types (a, b, exact))
844 {
845 if (probe == base && exact)
846 base = TREE_CHAIN (probe);
847 length++;
848 break;
849 }
850 }
851 if (probe == NULL_TREE)
852 return false;
853 }
854 return !exact || base == NULL_TREE || length == list_length (t1);
855 }
856
857 /* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if
858 [] can match [size]. */
859
860 static bool
comp_array_types(tree t1,tree t2,bool allow_redeclaration)861 comp_array_types (tree t1, tree t2, bool allow_redeclaration)
862 {
863 tree d1;
864 tree d2;
865 tree max1, max2;
866
867 if (t1 == t2)
868 return true;
869
870 /* The type of the array elements must be the same. */
871 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
872 return false;
873
874 d1 = TYPE_DOMAIN (t1);
875 d2 = TYPE_DOMAIN (t2);
876
877 if (d1 == d2)
878 return true;
879
880 /* If one of the arrays is dimensionless, and the other has a
881 dimension, they are of different types. However, it is valid to
882 write:
883
884 extern int a[];
885 int a[3];
886
887 by [basic.link]:
888
889 declarations for an array object can specify
890 array types that differ by the presence or absence of a major
891 array bound (_dcl.array_). */
892 if (!d1 || !d2)
893 return allow_redeclaration;
894
895 /* Check that the dimensions are the same. */
896
897 if (!cp_tree_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2)))
898 return false;
899 max1 = TYPE_MAX_VALUE (d1);
900 max2 = TYPE_MAX_VALUE (d2);
901 if (processing_template_decl && !abi_version_at_least (2)
902 && !value_dependent_expression_p (max1)
903 && !value_dependent_expression_p (max2))
904 {
905 /* With abi-1 we do not fold non-dependent array bounds, (and
906 consequently mangle them incorrectly). We must therefore
907 fold them here, to verify the domains have the same
908 value. */
909 max1 = fold (max1);
910 max2 = fold (max2);
911 }
912
913 if (!cp_tree_equal (max1, max2))
914 return false;
915
916 return true;
917 }
918
919 /* Return true if T1 and T2 are related as allowed by STRICT. STRICT
920 is a bitwise-or of the COMPARE_* flags. */
921
922 bool
comptypes(tree t1,tree t2,int strict)923 comptypes (tree t1, tree t2, int strict)
924 {
925 if (t1 == t2)
926 return true;
927
928 /* Suppress errors caused by previously reported errors. */
929 if (t1 == error_mark_node || t2 == error_mark_node)
930 return false;
931
932 my_friendly_assert (TYPE_P (t1) && TYPE_P (t2), 20030623);
933
934 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the
935 current instantiation. */
936 if (TREE_CODE (t1) == TYPENAME_TYPE)
937 {
938 tree resolved = resolve_typename_type (t1, /*only_current_p=*/true);
939
940 if (resolved != error_mark_node)
941 t1 = resolved;
942 }
943
944 if (TREE_CODE (t2) == TYPENAME_TYPE)
945 {
946 tree resolved = resolve_typename_type (t2, /*only_current_p=*/true);
947
948 if (resolved != error_mark_node)
949 t2 = resolved;
950 }
951
952 /* If either type is the internal version of sizetype, use the
953 language version. */
954 if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
955 && TYPE_DOMAIN (t1))
956 t1 = TYPE_DOMAIN (t1);
957
958 if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
959 && TYPE_DOMAIN (t2))
960 t2 = TYPE_DOMAIN (t2);
961
962 if (TYPE_PTRMEMFUNC_P (t1))
963 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1);
964 if (TYPE_PTRMEMFUNC_P (t2))
965 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2);
966
967 /* Different classes of types can't be compatible. */
968 if (TREE_CODE (t1) != TREE_CODE (t2))
969 return false;
970
971 /* Qualifiers must match. For array types, we will check when we
972 recur on the array element types. */
973 if (TREE_CODE (t1) != ARRAY_TYPE
974 && TYPE_QUALS (t1) != TYPE_QUALS (t2))
975 return false;
976 if (TYPE_FOR_JAVA (t1) != TYPE_FOR_JAVA (t2))
977 return false;
978
979 /* Allow for two different type nodes which have essentially the same
980 definition. Note that we already checked for equality of the type
981 qualifiers (just above). */
982
983 if (TREE_CODE (t1) != ARRAY_TYPE
984 && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
985 return true;
986
987 if (!(*targetm.comp_type_attributes) (t1, t2))
988 return false;
989
990 switch (TREE_CODE (t1))
991 {
992 case TEMPLATE_TEMPLATE_PARM:
993 case BOUND_TEMPLATE_TEMPLATE_PARM:
994 if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2)
995 || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2))
996 return false;
997 if (!comp_template_parms
998 (DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t1)),
999 DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t2))))
1000 return false;
1001 if (TREE_CODE (t1) == TEMPLATE_TEMPLATE_PARM)
1002 return true;
1003 /* Don't check inheritance. */
1004 strict = COMPARE_STRICT;
1005 /* Fall through. */
1006
1007 case RECORD_TYPE:
1008 case UNION_TYPE:
1009 if (TYPE_TEMPLATE_INFO (t1) && TYPE_TEMPLATE_INFO (t2)
1010 && (TYPE_TI_TEMPLATE (t1) == TYPE_TI_TEMPLATE (t2)
1011 || TREE_CODE (t1) == BOUND_TEMPLATE_TEMPLATE_PARM)
1012 && comp_template_args (TYPE_TI_ARGS (t1), TYPE_TI_ARGS (t2)))
1013 return true;
1014
1015 if ((strict & COMPARE_BASE) && DERIVED_FROM_P (t1, t2))
1016 return true;
1017 else if ((strict & COMPARE_DERIVED) && DERIVED_FROM_P (t2, t1))
1018 return true;
1019
1020 return false;
1021
1022 case OFFSET_TYPE:
1023 if (!comptypes (TYPE_OFFSET_BASETYPE (t1), TYPE_OFFSET_BASETYPE (t2),
1024 strict & ~COMPARE_REDECLARATION))
1025 return false;
1026 /* Fall through. */
1027
1028 case POINTER_TYPE:
1029 case REFERENCE_TYPE:
1030 return same_type_p (TREE_TYPE (t1), TREE_TYPE (t2));
1031
1032 case METHOD_TYPE:
1033 case FUNCTION_TYPE:
1034 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
1035 return false;
1036 return compparms (TYPE_ARG_TYPES (t1), TYPE_ARG_TYPES (t2));
1037
1038 case ARRAY_TYPE:
1039 /* Target types must match incl. qualifiers. */
1040 return comp_array_types (t1, t2, !!(strict & COMPARE_REDECLARATION));
1041
1042 case TEMPLATE_TYPE_PARM:
1043 return (TEMPLATE_TYPE_IDX (t1) == TEMPLATE_TYPE_IDX (t2)
1044 && TEMPLATE_TYPE_LEVEL (t1) == TEMPLATE_TYPE_LEVEL (t2));
1045
1046 case TYPENAME_TYPE:
1047 if (!cp_tree_equal (TYPENAME_TYPE_FULLNAME (t1),
1048 TYPENAME_TYPE_FULLNAME (t2)))
1049 return false;
1050 return same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2));
1051
1052 case UNBOUND_CLASS_TEMPLATE:
1053 if (!cp_tree_equal (TYPE_IDENTIFIER (t1), TYPE_IDENTIFIER (t2)))
1054 return false;
1055 return same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2));
1056
1057 case COMPLEX_TYPE:
1058 return same_type_p (TREE_TYPE (t1), TREE_TYPE (t2));
1059
1060 default:
1061 break;
1062 }
1063 return false;
1064 }
1065
1066 /* Returns 1 if TYPE1 is at least as qualified as TYPE2. */
1067
1068 bool
at_least_as_qualified_p(tree type1,tree type2)1069 at_least_as_qualified_p (tree type1, tree type2)
1070 {
1071 int q1 = cp_type_quals (type1);
1072 int q2 = cp_type_quals (type2);
1073
1074 /* All qualifiers for TYPE2 must also appear in TYPE1. */
1075 return (q1 & q2) == q2;
1076 }
1077
1078 /* Returns 1 if TYPE1 is more qualified than TYPE2. */
1079
1080 bool
more_qualified_p(tree type1,tree type2)1081 more_qualified_p (tree type1, tree type2)
1082 {
1083 int q1 = cp_type_quals (type1);
1084 int q2 = cp_type_quals (type2);
1085
1086 return q1 != q2 && (q1 & q2) == q2;
1087 }
1088
1089 /* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is
1090 more cv-qualified that TYPE1, and 0 otherwise. */
1091
1092 int
comp_cv_qualification(tree type1,tree type2)1093 comp_cv_qualification (tree type1, tree type2)
1094 {
1095 int q1 = cp_type_quals (type1);
1096 int q2 = cp_type_quals (type2);
1097
1098 if (q1 == q2)
1099 return 0;
1100
1101 if ((q1 & q2) == q2)
1102 return 1;
1103 else if ((q1 & q2) == q1)
1104 return -1;
1105
1106 return 0;
1107 }
1108
1109 /* Returns 1 if the cv-qualification signature of TYPE1 is a proper
1110 subset of the cv-qualification signature of TYPE2, and the types
1111 are similar. Returns -1 if the other way 'round, and 0 otherwise. */
1112
1113 int
comp_cv_qual_signature(tree type1,tree type2)1114 comp_cv_qual_signature (tree type1, tree type2)
1115 {
1116 if (comp_ptr_ttypes_real (type2, type1, -1))
1117 return 1;
1118 else if (comp_ptr_ttypes_real (type1, type2, -1))
1119 return -1;
1120 else
1121 return 0;
1122 }
1123
1124 /* If two types share a common base type, return that basetype.
1125 If there is not a unique most-derived base type, this function
1126 returns ERROR_MARK_NODE. */
1127
1128 static tree
common_base_type(tree tt1,tree tt2)1129 common_base_type (tree tt1, tree tt2)
1130 {
1131 tree best = NULL_TREE;
1132 int i;
1133
1134 /* If one is a baseclass of another, that's good enough. */
1135 if (UNIQUELY_DERIVED_FROM_P (tt1, tt2))
1136 return tt1;
1137 if (UNIQUELY_DERIVED_FROM_P (tt2, tt1))
1138 return tt2;
1139
1140 /* Otherwise, try to find a unique baseclass of TT1
1141 that is shared by TT2, and follow that down. */
1142 for (i = CLASSTYPE_N_BASECLASSES (tt1)-1; i >= 0; i--)
1143 {
1144 tree basetype = TYPE_BINFO_BASETYPE (tt1, i);
1145 tree trial = common_base_type (basetype, tt2);
1146 if (trial)
1147 {
1148 if (trial == error_mark_node)
1149 return trial;
1150 if (best == NULL_TREE)
1151 best = trial;
1152 else if (best != trial)
1153 return error_mark_node;
1154 }
1155 }
1156
1157 /* Same for TT2. */
1158 for (i = CLASSTYPE_N_BASECLASSES (tt2)-1; i >= 0; i--)
1159 {
1160 tree basetype = TYPE_BINFO_BASETYPE (tt2, i);
1161 tree trial = common_base_type (tt1, basetype);
1162 if (trial)
1163 {
1164 if (trial == error_mark_node)
1165 return trial;
1166 if (best == NULL_TREE)
1167 best = trial;
1168 else if (best != trial)
1169 return error_mark_node;
1170 }
1171 }
1172 return best;
1173 }
1174
1175 /* Subroutines of `comptypes'. */
1176
1177 /* Return true if two parameter type lists PARMS1 and PARMS2 are
1178 equivalent in the sense that functions with those parameter types
1179 can have equivalent types. The two lists must be equivalent,
1180 element by element. */
1181
1182 bool
compparms(tree parms1,tree parms2)1183 compparms (tree parms1, tree parms2)
1184 {
1185 tree t1, t2;
1186
1187 /* An unspecified parmlist matches any specified parmlist
1188 whose argument types don't need default promotions. */
1189
1190 for (t1 = parms1, t2 = parms2;
1191 t1 || t2;
1192 t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
1193 {
1194 /* If one parmlist is shorter than the other,
1195 they fail to match. */
1196 if (!t1 || !t2)
1197 return false;
1198 if (!same_type_p (TREE_VALUE (t1), TREE_VALUE (t2)))
1199 return false;
1200 }
1201 return true;
1202 }
1203
1204
1205 /* Process a sizeof or alignof expression where the operand is a
1206 type. */
1207
1208 tree
cxx_sizeof_or_alignof_type(tree type,enum tree_code op,bool complain)1209 cxx_sizeof_or_alignof_type (tree type, enum tree_code op, bool complain)
1210 {
1211 enum tree_code type_code;
1212 tree value;
1213 const char *op_name;
1214
1215 my_friendly_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR, 20020720);
1216 if (type == error_mark_node)
1217 return error_mark_node;
1218
1219 if (processing_template_decl)
1220 {
1221 value = build_min (op, size_type_node, type);
1222 TREE_READONLY (value) = 1;
1223 return value;
1224 }
1225
1226 op_name = operator_name_info[(int) op].name;
1227
1228 type = non_reference (type);
1229 type_code = TREE_CODE (type);
1230
1231 if (type_code == METHOD_TYPE)
1232 {
1233 if (complain && (pedantic || warn_pointer_arith))
1234 pedwarn ("invalid application of `%s' to a member function", op_name);
1235 value = size_one_node;
1236 }
1237 else
1238 value = c_sizeof_or_alignof_type (complete_type (type), op, complain);
1239
1240 return value;
1241 }
1242
1243 /* Process a sizeof or alignof expression where the operand is an
1244 expression. */
1245
1246 tree
cxx_sizeof_or_alignof_expr(tree e,enum tree_code op)1247 cxx_sizeof_or_alignof_expr (tree e, enum tree_code op)
1248 {
1249 const char *op_name = operator_name_info[(int) op].name;
1250
1251 if (e == error_mark_node)
1252 return error_mark_node;
1253
1254 if (processing_template_decl)
1255 {
1256 e = build_min (op, size_type_node, e);
1257 TREE_SIDE_EFFECTS (e) = 0;
1258 TREE_READONLY (e) = 1;
1259
1260 return e;
1261 }
1262
1263 if (TREE_CODE (e) == COMPONENT_REF
1264 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL
1265 && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1)))
1266 {
1267 error ("invalid application of `%s' to a bit-field", op_name);
1268 e = char_type_node;
1269 }
1270 else if (is_overloaded_fn (e))
1271 {
1272 pedwarn ("ISO C++ forbids applying `%s' to an expression of function type", op_name);
1273 e = char_type_node;
1274 }
1275 else if (type_unknown_p (e))
1276 {
1277 cxx_incomplete_type_error (e, TREE_TYPE (e));
1278 e = char_type_node;
1279 }
1280 else
1281 e = TREE_TYPE (e);
1282
1283 return cxx_sizeof_or_alignof_type (e, op, true);
1284 }
1285
1286
1287 /* EXPR is being used in a context that is not a function call.
1288 Enforce:
1289
1290 [expr.ref]
1291
1292 The expression can be used only as the left-hand operand of a
1293 member function call.
1294
1295 [expr.mptr.operator]
1296
1297 If the result of .* or ->* is a function, then that result can be
1298 used only as the operand for the function call operator ().
1299
1300 by issuing an error message if appropriate. Returns true iff EXPR
1301 violates these rules. */
1302
1303 bool
invalid_nonstatic_memfn_p(tree expr)1304 invalid_nonstatic_memfn_p (tree expr)
1305 {
1306 if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE)
1307 {
1308 error ("invalid use of non-static member function");
1309 return true;
1310 }
1311 return false;
1312 }
1313
1314 /* Perform the conversions in [expr] that apply when an lvalue appears
1315 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and
1316 function-to-pointer conversions.
1317
1318 In addition manifest constants are replaced by their values. */
1319
1320 tree
decay_conversion(tree exp)1321 decay_conversion (tree exp)
1322 {
1323 tree type;
1324 enum tree_code code;
1325
1326 type = TREE_TYPE (exp);
1327 code = TREE_CODE (type);
1328
1329 if (code == REFERENCE_TYPE)
1330 {
1331 exp = convert_from_reference (exp);
1332 type = TREE_TYPE (exp);
1333 code = TREE_CODE (type);
1334 }
1335
1336 if (type == error_mark_node)
1337 return error_mark_node;
1338
1339 if (type_unknown_p (exp))
1340 {
1341 cxx_incomplete_type_error (exp, TREE_TYPE (exp));
1342 return error_mark_node;
1343 }
1344
1345 /* Constants can be used directly unless they're not loadable. */
1346 if (TREE_CODE (exp) == CONST_DECL)
1347 exp = DECL_INITIAL (exp);
1348 /* Replace a nonvolatile const static variable with its value. We
1349 don't do this for arrays, though; we want the address of the
1350 first element of the array, not the address of the first element
1351 of its initializing constant. */
1352 else if (code != ARRAY_TYPE)
1353 {
1354 exp = decl_constant_value (exp);
1355 type = TREE_TYPE (exp);
1356 }
1357
1358 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
1359 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */
1360
1361 if (code == VOID_TYPE)
1362 {
1363 error ("void value not ignored as it ought to be");
1364 return error_mark_node;
1365 }
1366 if (invalid_nonstatic_memfn_p (exp))
1367 return error_mark_node;
1368 if (code == FUNCTION_TYPE || is_overloaded_fn (exp))
1369 return build_unary_op (ADDR_EXPR, exp, 0);
1370 if (code == ARRAY_TYPE)
1371 {
1372 tree adr;
1373 tree ptrtype;
1374
1375 if (TREE_CODE (exp) == INDIRECT_REF)
1376 return build_nop (build_pointer_type (TREE_TYPE (type)),
1377 TREE_OPERAND (exp, 0));
1378
1379 if (TREE_CODE (exp) == COMPOUND_EXPR)
1380 {
1381 tree op1 = decay_conversion (TREE_OPERAND (exp, 1));
1382 return build (COMPOUND_EXPR, TREE_TYPE (op1),
1383 TREE_OPERAND (exp, 0), op1);
1384 }
1385
1386 if (!lvalue_p (exp)
1387 && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp)))
1388 {
1389 error ("invalid use of non-lvalue array");
1390 return error_mark_node;
1391 }
1392
1393 ptrtype = build_pointer_type (TREE_TYPE (type));
1394
1395 if (TREE_CODE (exp) == VAR_DECL)
1396 {
1397 if (!cxx_mark_addressable (exp))
1398 return error_mark_node;
1399 adr = build_nop (ptrtype, build_address (exp));
1400 TREE_SIDE_EFFECTS (adr) = 0; /* Default would be, same as EXP. */
1401 return adr;
1402 }
1403 /* This way is better for a COMPONENT_REF since it can
1404 simplify the offset for a component. */
1405 adr = build_unary_op (ADDR_EXPR, exp, 1);
1406 return cp_convert (ptrtype, adr);
1407 }
1408
1409 /* [basic.lval]: Class rvalues can have cv-qualified types; non-class
1410 rvalues always have cv-unqualified types. */
1411 if (! CLASS_TYPE_P (type))
1412 exp = cp_convert (TYPE_MAIN_VARIANT (type), exp);
1413
1414 return exp;
1415 }
1416
1417 tree
default_conversion(tree exp)1418 default_conversion (tree exp)
1419 {
1420 exp = decay_conversion (exp);
1421
1422 if (INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (exp)))
1423 exp = perform_integral_promotions (exp);
1424
1425 return exp;
1426 }
1427
1428 /* EXPR is an expression with an integral or enumeration type.
1429 Perform the integral promotions in [conv.prom], and return the
1430 converted value. */
1431
1432 tree
perform_integral_promotions(tree expr)1433 perform_integral_promotions (tree expr)
1434 {
1435 tree type;
1436 tree promoted_type;
1437
1438 type = TREE_TYPE (expr);
1439 my_friendly_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type), 20030703);
1440 promoted_type = type_promotes_to (type);
1441 if (type != promoted_type)
1442 expr = cp_convert (promoted_type, expr);
1443 return expr;
1444 }
1445
1446 /* Take the address of an inline function without setting TREE_ADDRESSABLE
1447 or TREE_USED. */
1448
1449 tree
inline_conversion(tree exp)1450 inline_conversion (tree exp)
1451 {
1452 if (TREE_CODE (exp) == FUNCTION_DECL)
1453 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1454
1455 return exp;
1456 }
1457
1458 /* Returns nonzero iff exp is a STRING_CST or the result of applying
1459 decay_conversion to one. */
1460
1461 int
string_conv_p(tree totype,tree exp,int warn)1462 string_conv_p (tree totype, tree exp, int warn)
1463 {
1464 tree t;
1465
1466 if (! flag_const_strings || TREE_CODE (totype) != POINTER_TYPE)
1467 return 0;
1468
1469 t = TREE_TYPE (totype);
1470 if (!same_type_p (t, char_type_node)
1471 && !same_type_p (t, wchar_type_node))
1472 return 0;
1473
1474 if (TREE_CODE (exp) == STRING_CST)
1475 {
1476 /* Make sure that we don't try to convert between char and wchar_t. */
1477 if (!same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (exp))), t))
1478 return 0;
1479 }
1480 else
1481 {
1482 /* Is this a string constant which has decayed to 'const char *'? */
1483 t = build_pointer_type (build_qualified_type (t, TYPE_QUAL_CONST));
1484 if (!same_type_p (TREE_TYPE (exp), t))
1485 return 0;
1486 STRIP_NOPS (exp);
1487 if (TREE_CODE (exp) != ADDR_EXPR
1488 || TREE_CODE (TREE_OPERAND (exp, 0)) != STRING_CST)
1489 return 0;
1490 }
1491
1492 /* This warning is not very useful, as it complains about printf. */
1493 if (warn && warn_write_strings)
1494 warning ("deprecated conversion from string constant to `%T'", totype);
1495
1496 return 1;
1497 }
1498
1499 /* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we
1500 can, for example, use as an lvalue. This code used to be in
1501 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c'
1502 expressions, where we're dealing with aggregates. But now it's again only
1503 called from unary_complex_lvalue. The case (in particular) that led to
1504 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd
1505 get it there. */
1506
1507 static tree
rationalize_conditional_expr(enum tree_code code,tree t)1508 rationalize_conditional_expr (enum tree_code code, tree t)
1509 {
1510 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that
1511 the first operand is always the one to be used if both operands
1512 are equal, so we know what conditional expression this used to be. */
1513 if (TREE_CODE (t) == MIN_EXPR || TREE_CODE (t) == MAX_EXPR)
1514 {
1515 return
1516 build_conditional_expr (build_x_binary_op ((TREE_CODE (t) == MIN_EXPR
1517 ? LE_EXPR : GE_EXPR),
1518 TREE_OPERAND (t, 0),
1519 TREE_OPERAND (t, 1),
1520 /*overloaded_p=*/NULL),
1521 build_unary_op (code, TREE_OPERAND (t, 0), 0),
1522 build_unary_op (code, TREE_OPERAND (t, 1), 0));
1523 }
1524
1525 return
1526 build_conditional_expr (TREE_OPERAND (t, 0),
1527 build_unary_op (code, TREE_OPERAND (t, 1), 0),
1528 build_unary_op (code, TREE_OPERAND (t, 2), 0));
1529 }
1530
1531 /* Given the TYPE of an anonymous union field inside T, return the
1532 FIELD_DECL for the field. If not found return NULL_TREE. Because
1533 anonymous unions can nest, we must also search all anonymous unions
1534 that are directly reachable. */
1535
1536 tree
lookup_anon_field(tree t,tree type)1537 lookup_anon_field (tree t, tree type)
1538 {
1539 tree field;
1540
1541 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
1542 {
1543 if (TREE_STATIC (field))
1544 continue;
1545 if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field))
1546 continue;
1547
1548 /* If we find it directly, return the field. */
1549 if (DECL_NAME (field) == NULL_TREE
1550 && type == TYPE_MAIN_VARIANT (TREE_TYPE (field)))
1551 {
1552 return field;
1553 }
1554
1555 /* Otherwise, it could be nested, search harder. */
1556 if (DECL_NAME (field) == NULL_TREE
1557 && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
1558 {
1559 tree subfield = lookup_anon_field (TREE_TYPE (field), type);
1560 if (subfield)
1561 return subfield;
1562 }
1563 }
1564 return NULL_TREE;
1565 }
1566
1567 /* Build an expression representing OBJECT.MEMBER. OBJECT is an
1568 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is
1569 non-NULL, it indicates the path to the base used to name MEMBER.
1570 If PRESERVE_REFERENCE is true, the expression returned will have
1571 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression
1572 returned will have the type referred to by the reference.
1573
1574 This function does not perform access control; that is either done
1575 earlier by the parser when the name of MEMBER is resolved to MEMBER
1576 itself, or later when overload resolution selects one of the
1577 functions indicated by MEMBER. */
1578
1579 tree
build_class_member_access_expr(tree object,tree member,tree access_path,bool preserve_reference)1580 build_class_member_access_expr (tree object, tree member,
1581 tree access_path, bool preserve_reference)
1582 {
1583 tree object_type;
1584 tree member_scope;
1585 tree result = NULL_TREE;
1586
1587 if (object == error_mark_node || member == error_mark_node)
1588 return error_mark_node;
1589
1590 if (TREE_CODE (member) == PSEUDO_DTOR_EXPR)
1591 return member;
1592
1593 my_friendly_assert (DECL_P (member) || BASELINK_P (member),
1594 20020801);
1595
1596 /* [expr.ref]
1597
1598 The type of the first expression shall be "class object" (of a
1599 complete type). */
1600 object_type = TREE_TYPE (object);
1601 if (!currently_open_class (object_type)
1602 && !complete_type_or_else (object_type, object))
1603 return error_mark_node;
1604 if (!CLASS_TYPE_P (object_type))
1605 {
1606 error ("request for member `%D' in `%E', which is of non-class type `%T'",
1607 member, object, object_type);
1608 return error_mark_node;
1609 }
1610
1611 /* The standard does not seem to actually say that MEMBER must be a
1612 member of OBJECT_TYPE. However, that is clearly what is
1613 intended. */
1614 if (DECL_P (member))
1615 {
1616 member_scope = DECL_CLASS_CONTEXT (member);
1617 mark_used (member);
1618 if (TREE_DEPRECATED (member))
1619 warn_deprecated_use (member);
1620 }
1621 else
1622 member_scope = BINFO_TYPE (BASELINK_BINFO (member));
1623 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will
1624 presently be the anonymous union. Go outwards until we find a
1625 type related to OBJECT_TYPE. */
1626 while (ANON_AGGR_TYPE_P (member_scope)
1627 && !same_type_ignoring_top_level_qualifiers_p (member_scope,
1628 object_type))
1629 member_scope = TYPE_CONTEXT (member_scope);
1630 if (!member_scope || !DERIVED_FROM_P (member_scope, object_type))
1631 {
1632 if (TREE_CODE (member) == FIELD_DECL)
1633 error ("invalid use of nonstatic data member '%E'", member);
1634 else
1635 error ("`%D' is not a member of `%T'", member, object_type);
1636 return error_mark_node;
1637 }
1638
1639 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into
1640 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue
1641 in the frontend; only _DECLs and _REFs are lvalues in the backend. */
1642 {
1643 tree temp = unary_complex_lvalue (ADDR_EXPR, object);
1644 if (temp)
1645 object = build_indirect_ref (temp, NULL);
1646 }
1647
1648 /* In [expr.ref], there is an explicit list of the valid choices for
1649 MEMBER. We check for each of those cases here. */
1650 if (TREE_CODE (member) == VAR_DECL)
1651 {
1652 /* A static data member. */
1653 result = member;
1654 /* If OBJECT has side-effects, they are supposed to occur. */
1655 if (TREE_SIDE_EFFECTS (object))
1656 result = build (COMPOUND_EXPR, TREE_TYPE (result), object, result);
1657 }
1658 else if (TREE_CODE (member) == FIELD_DECL)
1659 {
1660 /* A non-static data member. */
1661 bool null_object_p;
1662 int type_quals;
1663 tree member_type;
1664
1665 null_object_p = (TREE_CODE (object) == INDIRECT_REF
1666 && integer_zerop (TREE_OPERAND (object, 0)));
1667
1668 /* Convert OBJECT to the type of MEMBER. */
1669 if (!same_type_p (TYPE_MAIN_VARIANT (object_type),
1670 TYPE_MAIN_VARIANT (member_scope)))
1671 {
1672 tree binfo;
1673 base_kind kind;
1674
1675 binfo = lookup_base (access_path ? access_path : object_type,
1676 member_scope, ba_ignore, &kind);
1677 if (binfo == error_mark_node)
1678 return error_mark_node;
1679
1680 /* It is invalid to try to get to a virtual base of a
1681 NULL object. The most common cause is invalid use of
1682 offsetof macro. */
1683 if (null_object_p && kind == bk_via_virtual)
1684 {
1685 error ("invalid access to non-static data member `%D' of NULL object",
1686 member);
1687 error ("(perhaps the `offsetof' macro was used incorrectly)");
1688 return error_mark_node;
1689 }
1690
1691 /* Convert to the base. */
1692 object = build_base_path (PLUS_EXPR, object, binfo,
1693 /*nonnull=*/1);
1694 /* If we found the base successfully then we should be able
1695 to convert to it successfully. */
1696 my_friendly_assert (object != error_mark_node,
1697 20020801);
1698 }
1699
1700 /* Complain about other invalid uses of offsetof, even though they will
1701 give the right answer. Note that we complain whether or not they
1702 actually used the offsetof macro, since there's no way to know at this
1703 point. So we just give a warning, instead of a pedwarn. */
1704 if (null_object_p && warn_invalid_offsetof
1705 && CLASSTYPE_NON_POD_P (object_type))
1706 {
1707 warning ("invalid access to non-static data member `%D' of NULL object",
1708 member);
1709 warning ("(perhaps the `offsetof' macro was used incorrectly)");
1710 }
1711
1712 /* If MEMBER is from an anonymous aggregate, we have converted
1713 OBJECT so that it refers to the class containing the
1714 anonymous union. Generate a reference to the anonymous union
1715 itself, and recur to find MEMBER. */
1716 if (ANON_AGGR_TYPE_P (DECL_CONTEXT (member))
1717 /* When this code is called from build_field_call, the
1718 object already has the type of the anonymous union.
1719 That is because the COMPONENT_REF was already
1720 constructed, and was then disassembled before calling
1721 build_field_call. After the function-call code is
1722 cleaned up, this waste can be eliminated. */
1723 && (!same_type_ignoring_top_level_qualifiers_p
1724 (TREE_TYPE (object), DECL_CONTEXT (member))))
1725 {
1726 tree anonymous_union;
1727
1728 anonymous_union = lookup_anon_field (TREE_TYPE (object),
1729 DECL_CONTEXT (member));
1730 object = build_class_member_access_expr (object,
1731 anonymous_union,
1732 /*access_path=*/NULL_TREE,
1733 preserve_reference);
1734 }
1735
1736 /* Compute the type of the field, as described in [expr.ref]. */
1737 type_quals = TYPE_UNQUALIFIED;
1738 member_type = TREE_TYPE (member);
1739 if (TREE_CODE (member_type) != REFERENCE_TYPE)
1740 {
1741 type_quals = (cp_type_quals (member_type)
1742 | cp_type_quals (object_type));
1743
1744 /* A field is const (volatile) if the enclosing object, or the
1745 field itself, is const (volatile). But, a mutable field is
1746 not const, even within a const object. */
1747 if (DECL_MUTABLE_P (member))
1748 type_quals &= ~TYPE_QUAL_CONST;
1749 member_type = cp_build_qualified_type (member_type, type_quals);
1750 }
1751
1752 result = fold (build (COMPONENT_REF, member_type, object, member));
1753
1754 /* Mark the expression const or volatile, as appropriate. Even
1755 though we've dealt with the type above, we still have to mark the
1756 expression itself. */
1757 if (type_quals & TYPE_QUAL_CONST)
1758 TREE_READONLY (result) = 1;
1759 else if (type_quals & TYPE_QUAL_VOLATILE)
1760 TREE_THIS_VOLATILE (result) = 1;
1761 }
1762 else if (BASELINK_P (member))
1763 {
1764 /* The member is a (possibly overloaded) member function. */
1765 tree functions;
1766 tree type;
1767
1768 /* If the MEMBER is exactly one static member function, then we
1769 know the type of the expression. Otherwise, we must wait
1770 until overload resolution has been performed. */
1771 functions = BASELINK_FUNCTIONS (member);
1772 if (TREE_CODE (functions) == FUNCTION_DECL
1773 && DECL_STATIC_FUNCTION_P (functions))
1774 type = TREE_TYPE (functions);
1775 else
1776 type = unknown_type_node;
1777 /* Note that we do not convert OBJECT to the BASELINK_BINFO
1778 base. That will happen when the function is called. */
1779 result = build (COMPONENT_REF, type, object, member);
1780 }
1781 else if (TREE_CODE (member) == CONST_DECL)
1782 {
1783 /* The member is an enumerator. */
1784 result = member;
1785 /* If OBJECT has side-effects, they are supposed to occur. */
1786 if (TREE_SIDE_EFFECTS (object))
1787 result = build (COMPOUND_EXPR, TREE_TYPE (result),
1788 object, result);
1789 }
1790 else
1791 {
1792 error ("invalid use of `%D'", member);
1793 return error_mark_node;
1794 }
1795
1796 if (!preserve_reference)
1797 /* [expr.ref]
1798
1799 If E2 is declared to have type "reference to T", then ... the
1800 type of E1.E2 is T. */
1801 result = convert_from_reference (result);
1802
1803 return result;
1804 }
1805
1806 /* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if
1807 SCOPE is NULL, by OBJECT.~DTOR_NAME. */
1808
1809 static tree
lookup_destructor(tree object,tree scope,tree dtor_name)1810 lookup_destructor (tree object, tree scope, tree dtor_name)
1811 {
1812 tree object_type = TREE_TYPE (object);
1813 tree dtor_type = TREE_OPERAND (dtor_name, 0);
1814 tree expr;
1815
1816 if (scope && !check_dtor_name (scope, dtor_name))
1817 {
1818 error ("qualified type `%T' does not match destructor name `~%T'",
1819 scope, dtor_type);
1820 return error_mark_node;
1821 }
1822 if (!DERIVED_FROM_P (dtor_type, TYPE_MAIN_VARIANT (object_type)))
1823 {
1824 error ("the type being destroyed is `%T', but the destructor refers to `%T'",
1825 TYPE_MAIN_VARIANT (object_type), dtor_type);
1826 return error_mark_node;
1827 }
1828 if (!TYPE_HAS_DESTRUCTOR (dtor_type))
1829 return build (PSEUDO_DTOR_EXPR, void_type_node, object, scope,
1830 dtor_type);
1831 expr = lookup_member (dtor_type, complete_dtor_identifier,
1832 /*protect=*/1, /*want_type=*/false);
1833 expr = (adjust_result_of_qualified_name_lookup
1834 (expr, dtor_type, object_type));
1835 return expr;
1836 }
1837
1838 /* This function is called by the parser to process a class member
1839 access expression of the form OBJECT.NAME. NAME is a node used by
1840 the parser to represent a name; it is not yet a DECL. It may,
1841 however, be a BASELINK where the BASELINK_FUNCTIONS is a
1842 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and
1843 there is no reason to do the lookup twice, so the parser keeps the
1844 BASELINK. */
1845
1846 tree
finish_class_member_access_expr(tree object,tree name)1847 finish_class_member_access_expr (tree object, tree name)
1848 {
1849 tree expr;
1850 tree object_type;
1851 tree member;
1852 tree access_path = NULL_TREE;
1853 tree orig_object = object;
1854 tree orig_name = name;
1855
1856 if (object == error_mark_node || name == error_mark_node)
1857 return error_mark_node;
1858
1859 object_type = TREE_TYPE (object);
1860
1861 if (processing_template_decl)
1862 {
1863 if (/* If OBJECT_TYPE is dependent, so is OBJECT.NAME. */
1864 dependent_type_p (object_type)
1865 /* If NAME is just an IDENTIFIER_NODE, then the expression
1866 is dependent. */
1867 || TREE_CODE (object) == IDENTIFIER_NODE
1868 /* If NAME is "f<args>", where either 'f' or 'args' is
1869 dependent, then the expression is dependent. */
1870 || (TREE_CODE (name) == TEMPLATE_ID_EXPR
1871 && dependent_template_id_p (TREE_OPERAND (name, 0),
1872 TREE_OPERAND (name, 1)))
1873 /* If NAME is "T::X" where "T" is dependent, then the
1874 expression is dependent. */
1875 || (TREE_CODE (name) == SCOPE_REF
1876 && TYPE_P (TREE_OPERAND (name, 0))
1877 && dependent_type_p (TREE_OPERAND (name, 0))))
1878 return build_min_nt (COMPONENT_REF, object, name);
1879 object = build_non_dependent_expr (object);
1880 }
1881
1882 if (TREE_CODE (object_type) == REFERENCE_TYPE)
1883 {
1884 object = convert_from_reference (object);
1885 object_type = TREE_TYPE (object);
1886 }
1887
1888 /* [expr.ref]
1889
1890 The type of the first expression shall be "class object" (of a
1891 complete type). */
1892 if (!currently_open_class (object_type)
1893 && !complete_type_or_else (object_type, object))
1894 return error_mark_node;
1895 if (!CLASS_TYPE_P (object_type))
1896 {
1897 error ("request for member `%D' in `%E', which is of non-class type `%T'",
1898 name, object, object_type);
1899 return error_mark_node;
1900 }
1901
1902 if (BASELINK_P (name))
1903 {
1904 /* A member function that has already been looked up. */
1905 my_friendly_assert ((TREE_CODE (BASELINK_FUNCTIONS (name))
1906 == TEMPLATE_ID_EXPR),
1907 20020805);
1908 member = name;
1909 }
1910 else
1911 {
1912 bool is_template_id = false;
1913 tree template_args = NULL_TREE;
1914 tree scope;
1915
1916 if (TREE_CODE (name) == TEMPLATE_ID_EXPR)
1917 {
1918 is_template_id = true;
1919 template_args = TREE_OPERAND (name, 1);
1920 name = TREE_OPERAND (name, 0);
1921
1922 if (TREE_CODE (name) == OVERLOAD)
1923 name = DECL_NAME (get_first_fn (name));
1924 else if (DECL_P (name))
1925 name = DECL_NAME (name);
1926 }
1927
1928 if (TREE_CODE (name) == SCOPE_REF)
1929 {
1930 /* A qualified name. The qualifying class or namespace `S' has
1931 already been looked up; it is either a TYPE or a
1932 NAMESPACE_DECL. The member name is either an IDENTIFIER_NODE
1933 or a BIT_NOT_EXPR. */
1934 scope = TREE_OPERAND (name, 0);
1935 name = TREE_OPERAND (name, 1);
1936 my_friendly_assert ((CLASS_TYPE_P (scope)
1937 || TREE_CODE (scope) == NAMESPACE_DECL),
1938 20020804);
1939 my_friendly_assert ((TREE_CODE (name) == IDENTIFIER_NODE
1940 || TREE_CODE (name) == BIT_NOT_EXPR),
1941 20020804);
1942
1943 /* If SCOPE is a namespace, then the qualified name does not
1944 name a member of OBJECT_TYPE. */
1945 if (TREE_CODE (scope) == NAMESPACE_DECL)
1946 {
1947 error ("`%D::%D' is not a member of `%T'",
1948 scope, name, object_type);
1949 return error_mark_node;
1950 }
1951
1952 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */
1953 access_path = lookup_base (object_type, scope, ba_check, NULL);
1954 if (access_path == error_mark_node)
1955 return error_mark_node;
1956 if (!access_path)
1957 {
1958 error ("`%T' is not a base of `%T'", scope, object_type);
1959 return error_mark_node;
1960 }
1961 }
1962 else
1963 {
1964 scope = NULL_TREE;
1965 access_path = object_type;
1966 }
1967
1968 if (TREE_CODE (name) == BIT_NOT_EXPR)
1969 member = lookup_destructor (object, scope, name);
1970 else
1971 {
1972 /* Look up the member. */
1973 member = lookup_member (access_path, name, /*protect=*/1,
1974 /*want_type=*/false);
1975 if (member == NULL_TREE)
1976 {
1977 error ("'%D' has no member named '%E'", object_type, name);
1978 return error_mark_node;
1979 }
1980 if (member == error_mark_node)
1981 return error_mark_node;
1982 }
1983
1984 if (is_template_id)
1985 {
1986 tree template = member;
1987
1988 if (BASELINK_P (template))
1989 template = lookup_template_function (template, template_args);
1990 else
1991 {
1992 error ("`%D' is not a member template function", name);
1993 return error_mark_node;
1994 }
1995 }
1996 }
1997
1998 if (TREE_DEPRECATED (member))
1999 warn_deprecated_use (member);
2000
2001 expr = build_class_member_access_expr (object, member, access_path,
2002 /*preserve_reference=*/false);
2003 if (processing_template_decl && expr != error_mark_node)
2004 return build_min_non_dep (COMPONENT_REF, expr,
2005 orig_object, orig_name);
2006 return expr;
2007 }
2008
2009 /* Return an expression for the MEMBER_NAME field in the internal
2010 representation of PTRMEM, a pointer-to-member function. (Each
2011 pointer-to-member function type gets its own RECORD_TYPE so it is
2012 more convenient to access the fields by name than by FIELD_DECL.)
2013 This routine converts the NAME to a FIELD_DECL and then creates the
2014 node for the complete expression. */
2015
2016 tree
build_ptrmemfunc_access_expr(tree ptrmem,tree member_name)2017 build_ptrmemfunc_access_expr (tree ptrmem, tree member_name)
2018 {
2019 tree ptrmem_type;
2020 tree member;
2021 tree member_type;
2022
2023 /* This code is a stripped down version of
2024 build_class_member_access_expr. It does not work to use that
2025 routine directly because it expects the object to be of class
2026 type. */
2027 ptrmem_type = TREE_TYPE (ptrmem);
2028 my_friendly_assert (TYPE_PTRMEMFUNC_P (ptrmem_type), 20020804);
2029 member = lookup_member (ptrmem_type, member_name, /*protect=*/0,
2030 /*want_type=*/false);
2031 member_type = cp_build_qualified_type (TREE_TYPE (member),
2032 cp_type_quals (ptrmem_type));
2033 return fold (build (COMPONENT_REF, member_type, ptrmem, member));
2034 }
2035
2036 /* Given an expression PTR for a pointer, return an expression
2037 for the value pointed to.
2038 ERRORSTRING is the name of the operator to appear in error messages.
2039
2040 This function may need to overload OPERATOR_FNNAME.
2041 Must also handle REFERENCE_TYPEs for C++. */
2042
2043 tree
build_x_indirect_ref(tree expr,const char * errorstring)2044 build_x_indirect_ref (tree expr, const char *errorstring)
2045 {
2046 tree orig_expr = expr;
2047 tree rval;
2048
2049 if (processing_template_decl)
2050 {
2051 if (type_dependent_expression_p (expr))
2052 return build_min_nt (INDIRECT_REF, expr);
2053 expr = build_non_dependent_expr (expr);
2054 }
2055
2056 rval = build_new_op (INDIRECT_REF, LOOKUP_NORMAL, expr, NULL_TREE,
2057 NULL_TREE, /*overloaded_p=*/NULL);
2058 if (!rval)
2059 rval = build_indirect_ref (expr, errorstring);
2060
2061 if (processing_template_decl && rval != error_mark_node)
2062 return build_min_non_dep (INDIRECT_REF, rval, orig_expr);
2063 else
2064 return rval;
2065 }
2066
2067 tree
build_indirect_ref(tree ptr,const char * errorstring)2068 build_indirect_ref (tree ptr, const char *errorstring)
2069 {
2070 tree pointer, type;
2071
2072 if (ptr == error_mark_node)
2073 return error_mark_node;
2074
2075 if (ptr == current_class_ptr)
2076 return current_class_ref;
2077
2078 pointer = (TREE_CODE (TREE_TYPE (ptr)) == REFERENCE_TYPE
2079 ? ptr : decay_conversion (ptr));
2080 type = TREE_TYPE (pointer);
2081
2082 if (TYPE_PTR_P (type) || TREE_CODE (type) == REFERENCE_TYPE)
2083 {
2084 /* [expr.unary.op]
2085
2086 If the type of the expression is "pointer to T," the type
2087 of the result is "T."
2088
2089 We must use the canonical variant because certain parts of
2090 the back end, like fold, do pointer comparisons between
2091 types. */
2092 tree t = canonical_type_variant (TREE_TYPE (type));
2093
2094 if (VOID_TYPE_P (t))
2095 {
2096 /* A pointer to incomplete type (other than cv void) can be
2097 dereferenced [expr.unary.op]/1 */
2098 error ("`%T' is not a pointer-to-object type", type);
2099 return error_mark_node;
2100 }
2101 else if (TREE_CODE (pointer) == ADDR_EXPR
2102 && same_type_p (t, TREE_TYPE (TREE_OPERAND (pointer, 0))))
2103 /* The POINTER was something like `&x'. We simplify `*&x' to
2104 `x'. */
2105 return TREE_OPERAND (pointer, 0);
2106 else
2107 {
2108 tree ref = build1 (INDIRECT_REF, t, pointer);
2109
2110 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2111 so that we get the proper error message if the result is used
2112 to assign to. Also, &* is supposed to be a no-op. */
2113 TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
2114 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
2115 TREE_SIDE_EFFECTS (ref)
2116 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (pointer));
2117 return ref;
2118 }
2119 }
2120 /* `pointer' won't be an error_mark_node if we were given a
2121 pointer to member, so it's cool to check for this here. */
2122 else if (TYPE_PTR_TO_MEMBER_P (type))
2123 error ("invalid use of `%s' on pointer to member", errorstring);
2124 else if (pointer != error_mark_node)
2125 {
2126 if (errorstring)
2127 error ("invalid type argument of `%s'", errorstring);
2128 else
2129 error ("invalid type argument");
2130 }
2131 return error_mark_node;
2132 }
2133
2134 /* This handles expressions of the form "a[i]", which denotes
2135 an array reference.
2136
2137 This is logically equivalent in C to *(a+i), but we may do it differently.
2138 If A is a variable or a member, we generate a primitive ARRAY_REF.
2139 This avoids forcing the array out of registers, and can work on
2140 arrays that are not lvalues (for example, members of structures returned
2141 by functions).
2142
2143 If INDEX is of some user-defined type, it must be converted to
2144 integer type. Otherwise, to make a compatible PLUS_EXPR, it
2145 will inherit the type of the array, which will be some pointer type. */
2146
2147 tree
build_array_ref(tree array,tree idx)2148 build_array_ref (tree array, tree idx)
2149 {
2150 if (idx == 0)
2151 {
2152 error ("subscript missing in array reference");
2153 return error_mark_node;
2154 }
2155
2156 if (TREE_TYPE (array) == error_mark_node
2157 || TREE_TYPE (idx) == error_mark_node)
2158 return error_mark_node;
2159
2160 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference
2161 inside it. */
2162 switch (TREE_CODE (array))
2163 {
2164 case COMPOUND_EXPR:
2165 {
2166 tree value = build_array_ref (TREE_OPERAND (array, 1), idx);
2167 return build (COMPOUND_EXPR, TREE_TYPE (value),
2168 TREE_OPERAND (array, 0), value);
2169 }
2170
2171 case COND_EXPR:
2172 return build_conditional_expr
2173 (TREE_OPERAND (array, 0),
2174 build_array_ref (TREE_OPERAND (array, 1), idx),
2175 build_array_ref (TREE_OPERAND (array, 2), idx));
2176
2177 default:
2178 break;
2179 }
2180
2181 if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE
2182 && TREE_CODE (array) != INDIRECT_REF)
2183 {
2184 tree rval, type;
2185
2186 /* Subscripting with type char is likely to lose
2187 on a machine where chars are signed.
2188 So warn on any machine, but optionally.
2189 Don't warn for unsigned char since that type is safe.
2190 Don't warn for signed char because anyone who uses that
2191 must have done so deliberately. */
2192 if (warn_char_subscripts
2193 && TYPE_MAIN_VARIANT (TREE_TYPE (idx)) == char_type_node)
2194 warning ("array subscript has type `char'");
2195
2196 if (!INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (idx)))
2197 {
2198 error ("array subscript is not an integer");
2199 return error_mark_node;
2200 }
2201
2202 /* Apply integral promotions *after* noticing character types.
2203 (It is unclear why we do these promotions -- the standard
2204 does not say that we should. In fact, the natual thing would
2205 seem to be to convert IDX to ptrdiff_t; we're performing
2206 pointer arithmetic.) */
2207 idx = perform_integral_promotions (idx);
2208
2209 /* An array that is indexed by a non-constant
2210 cannot be stored in a register; we must be able to do
2211 address arithmetic on its address.
2212 Likewise an array of elements of variable size. */
2213 if (TREE_CODE (idx) != INTEGER_CST
2214 || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2215 && (TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array))))
2216 != INTEGER_CST)))
2217 {
2218 if (!cxx_mark_addressable (array))
2219 return error_mark_node;
2220 }
2221
2222 /* An array that is indexed by a constant value which is not within
2223 the array bounds cannot be stored in a register either; because we
2224 would get a crash in store_bit_field/extract_bit_field when trying
2225 to access a non-existent part of the register. */
2226 if (TREE_CODE (idx) == INTEGER_CST
2227 && TYPE_VALUES (TREE_TYPE (array))
2228 && ! int_fits_type_p (idx, TYPE_VALUES (TREE_TYPE (array))))
2229 {
2230 if (!cxx_mark_addressable (array))
2231 return error_mark_node;
2232 }
2233
2234 if (pedantic && !lvalue_p (array))
2235 pedwarn ("ISO C++ forbids subscripting non-lvalue array");
2236
2237 /* Note in C++ it is valid to subscript a `register' array, since
2238 it is valid to take the address of something with that
2239 storage specification. */
2240 if (extra_warnings)
2241 {
2242 tree foo = array;
2243 while (TREE_CODE (foo) == COMPONENT_REF)
2244 foo = TREE_OPERAND (foo, 0);
2245 if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo))
2246 warning ("subscripting array declared `register'");
2247 }
2248
2249 type = TREE_TYPE (TREE_TYPE (array));
2250 rval = build (ARRAY_REF, type, array, idx);
2251 /* Array ref is const/volatile if the array elements are
2252 or if the array is.. */
2253 TREE_READONLY (rval)
2254 |= (CP_TYPE_CONST_P (type) | TREE_READONLY (array));
2255 TREE_SIDE_EFFECTS (rval)
2256 |= (CP_TYPE_VOLATILE_P (type) | TREE_SIDE_EFFECTS (array));
2257 TREE_THIS_VOLATILE (rval)
2258 |= (CP_TYPE_VOLATILE_P (type) | TREE_THIS_VOLATILE (array));
2259 return require_complete_type (fold (rval));
2260 }
2261
2262 {
2263 tree ar = default_conversion (array);
2264 tree ind = default_conversion (idx);
2265
2266 /* Put the integer in IND to simplify error checking. */
2267 if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE)
2268 {
2269 tree temp = ar;
2270 ar = ind;
2271 ind = temp;
2272 }
2273
2274 if (ar == error_mark_node)
2275 return ar;
2276
2277 if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE)
2278 {
2279 error ("subscripted value is neither array nor pointer");
2280 return error_mark_node;
2281 }
2282 if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE)
2283 {
2284 error ("array subscript is not an integer");
2285 return error_mark_node;
2286 }
2287
2288 return build_indirect_ref (cp_build_binary_op (PLUS_EXPR, ar, ind),
2289 "array indexing");
2290 }
2291 }
2292
2293 /* Resolve a pointer to member function. INSTANCE is the object
2294 instance to use, if the member points to a virtual member.
2295
2296 This used to avoid checking for virtual functions if basetype
2297 has no virtual functions, according to an earlier ANSI draft.
2298 With the final ISO C++ rules, such an optimization is
2299 incorrect: A pointer to a derived member can be static_cast
2300 to pointer-to-base-member, as long as the dynamic object
2301 later has the right member. */
2302
2303 tree
get_member_function_from_ptrfunc(tree * instance_ptrptr,tree function)2304 get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function)
2305 {
2306 if (TREE_CODE (function) == OFFSET_REF)
2307 function = TREE_OPERAND (function, 1);
2308
2309 if (TYPE_PTRMEMFUNC_P (TREE_TYPE (function)))
2310 {
2311 tree idx, delta, e1, e2, e3, vtbl, basetype;
2312 tree fntype = TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (function));
2313
2314 tree instance_ptr = *instance_ptrptr;
2315 tree instance_save_expr = 0;
2316 if (instance_ptr == error_mark_node)
2317 {
2318 if (TREE_CODE (function) == PTRMEM_CST)
2319 {
2320 /* Extracting the function address from a pmf is only
2321 allowed with -Wno-pmf-conversions. It only works for
2322 pmf constants. */
2323 e1 = build_addr_func (PTRMEM_CST_MEMBER (function));
2324 e1 = convert (fntype, e1);
2325 return e1;
2326 }
2327 else
2328 {
2329 error ("object missing in use of `%E'", function);
2330 return error_mark_node;
2331 }
2332 }
2333
2334 if (TREE_SIDE_EFFECTS (instance_ptr))
2335 instance_ptr = instance_save_expr = save_expr (instance_ptr);
2336
2337 if (TREE_SIDE_EFFECTS (function))
2338 function = save_expr (function);
2339
2340 /* Start by extracting all the information from the PMF itself. */
2341 e3 = PFN_FROM_PTRMEMFUNC (function);
2342 delta = build_ptrmemfunc_access_expr (function, delta_identifier);
2343 idx = build1 (NOP_EXPR, vtable_index_type, e3);
2344 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION)
2345 {
2346 case ptrmemfunc_vbit_in_pfn:
2347 e1 = cp_build_binary_op (BIT_AND_EXPR, idx, integer_one_node);
2348 idx = cp_build_binary_op (MINUS_EXPR, idx, integer_one_node);
2349 break;
2350
2351 case ptrmemfunc_vbit_in_delta:
2352 e1 = cp_build_binary_op (BIT_AND_EXPR, delta, integer_one_node);
2353 delta = cp_build_binary_op (RSHIFT_EXPR, delta, integer_one_node);
2354 break;
2355
2356 default:
2357 abort ();
2358 }
2359
2360 /* Convert down to the right base before using the instance. First
2361 use the type... */
2362 basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (fntype));
2363 basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)),
2364 basetype, ba_check, NULL);
2365 instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 1);
2366 if (instance_ptr == error_mark_node)
2367 return error_mark_node;
2368 /* ...and then the delta in the PMF. */
2369 instance_ptr = build (PLUS_EXPR, TREE_TYPE (instance_ptr),
2370 instance_ptr, delta);
2371
2372 /* Hand back the adjusted 'this' argument to our caller. */
2373 *instance_ptrptr = instance_ptr;
2374
2375 /* Next extract the vtable pointer from the object. */
2376 vtbl = build1 (NOP_EXPR, build_pointer_type (vtbl_ptr_type_node),
2377 instance_ptr);
2378 vtbl = build_indirect_ref (vtbl, NULL);
2379
2380 /* Finally, extract the function pointer from the vtable. */
2381 e2 = fold (build (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, idx));
2382 e2 = build_indirect_ref (e2, NULL);
2383 TREE_CONSTANT (e2) = 1;
2384
2385 /* When using function descriptors, the address of the
2386 vtable entry is treated as a function pointer. */
2387 if (TARGET_VTABLE_USES_DESCRIPTORS)
2388 e2 = build1 (NOP_EXPR, TREE_TYPE (e2),
2389 build_unary_op (ADDR_EXPR, e2, /*noconvert=*/1));
2390
2391 TREE_TYPE (e2) = TREE_TYPE (e3);
2392 e1 = build_conditional_expr (e1, e2, e3);
2393
2394 /* Make sure this doesn't get evaluated first inside one of the
2395 branches of the COND_EXPR. */
2396 if (instance_save_expr)
2397 e1 = build (COMPOUND_EXPR, TREE_TYPE (e1),
2398 instance_save_expr, e1);
2399
2400 function = e1;
2401 }
2402 return function;
2403 }
2404
2405 tree
build_function_call(tree function,tree params)2406 build_function_call (tree function, tree params)
2407 {
2408 tree fntype, fndecl;
2409 tree coerced_params;
2410 tree result;
2411 tree name = NULL_TREE, assembler_name = NULL_TREE;
2412 int is_method;
2413 tree original = function;
2414
2415 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2416 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */
2417 if (TREE_CODE (function) == NOP_EXPR
2418 && TREE_TYPE (function) == TREE_TYPE (TREE_OPERAND (function, 0)))
2419 function = TREE_OPERAND (function, 0);
2420
2421 if (TREE_CODE (function) == FUNCTION_DECL)
2422 {
2423 name = DECL_NAME (function);
2424 assembler_name = DECL_ASSEMBLER_NAME (function);
2425
2426 mark_used (function);
2427 fndecl = function;
2428
2429 /* Convert anything with function type to a pointer-to-function. */
2430 if (pedantic && DECL_MAIN_P (function))
2431 pedwarn ("ISO C++ forbids calling `::main' from within program");
2432
2433 /* Differs from default_conversion by not setting TREE_ADDRESSABLE
2434 (because calling an inline function does not mean the function
2435 needs to be separately compiled). */
2436
2437 if (DECL_INLINE (function))
2438 function = inline_conversion (function);
2439 else
2440 function = build_addr_func (function);
2441 }
2442 else
2443 {
2444 fndecl = NULL_TREE;
2445
2446 function = build_addr_func (function);
2447 }
2448
2449 if (function == error_mark_node)
2450 return error_mark_node;
2451
2452 fntype = TREE_TYPE (function);
2453
2454 if (TYPE_PTRMEMFUNC_P (fntype))
2455 {
2456 error ("must use .* or ->* to call pointer-to-member function in `%E (...)'",
2457 original);
2458 return error_mark_node;
2459 }
2460
2461 is_method = (TREE_CODE (fntype) == POINTER_TYPE
2462 && TREE_CODE (TREE_TYPE (fntype)) == METHOD_TYPE);
2463
2464 if (!((TREE_CODE (fntype) == POINTER_TYPE
2465 && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE)
2466 || is_method
2467 || TREE_CODE (function) == TEMPLATE_ID_EXPR))
2468 {
2469 error ("`%E' cannot be used as a function", original);
2470 return error_mark_node;
2471 }
2472
2473 /* fntype now gets the type of function pointed to. */
2474 fntype = TREE_TYPE (fntype);
2475
2476 /* Convert the parameters to the types declared in the
2477 function prototype, or apply default promotions. */
2478
2479 coerced_params = convert_arguments (TYPE_ARG_TYPES (fntype),
2480 params, fndecl, LOOKUP_NORMAL);
2481 if (coerced_params == error_mark_node)
2482 return error_mark_node;
2483
2484 /* Check for errors in format strings. */
2485
2486 if (warn_format)
2487 check_function_format (NULL, TYPE_ATTRIBUTES (fntype), coerced_params);
2488
2489 /* Recognize certain built-in functions so we can make tree-codes
2490 other than CALL_EXPR. We do this when it enables fold-const.c
2491 to do something useful. */
2492
2493 if (TREE_CODE (function) == ADDR_EXPR
2494 && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL
2495 && DECL_BUILT_IN (TREE_OPERAND (function, 0)))
2496 {
2497 result = expand_tree_builtin (TREE_OPERAND (function, 0),
2498 params, coerced_params);
2499 if (result)
2500 return result;
2501 }
2502
2503 return build_cxx_call (function, params, coerced_params);
2504 }
2505
2506 /* Convert the actual parameter expressions in the list VALUES
2507 to the types in the list TYPELIST.
2508 If parmdecls is exhausted, or when an element has NULL as its type,
2509 perform the default conversions.
2510
2511 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages.
2512
2513 This is also where warnings about wrong number of args are generated.
2514
2515 Return a list of expressions for the parameters as converted.
2516
2517 Both VALUES and the returned value are chains of TREE_LIST nodes
2518 with the elements of the list in the TREE_VALUE slots of those nodes.
2519
2520 In C++, unspecified trailing parameters can be filled in with their
2521 default arguments, if such were specified. Do so here. */
2522
2523 tree
convert_arguments(tree typelist,tree values,tree fndecl,int flags)2524 convert_arguments (tree typelist, tree values, tree fndecl, int flags)
2525 {
2526 tree typetail, valtail;
2527 tree result = NULL_TREE;
2528 const char *called_thing = 0;
2529 int i = 0;
2530
2531 /* Argument passing is always copy-initialization. */
2532 flags |= LOOKUP_ONLYCONVERTING;
2533
2534 if (fndecl)
2535 {
2536 if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
2537 {
2538 if (DECL_NAME (fndecl) == NULL_TREE
2539 || IDENTIFIER_HAS_TYPE_VALUE (DECL_NAME (fndecl)))
2540 called_thing = "constructor";
2541 else
2542 called_thing = "member function";
2543 }
2544 else
2545 called_thing = "function";
2546 }
2547
2548 for (valtail = values, typetail = typelist;
2549 valtail;
2550 valtail = TREE_CHAIN (valtail), i++)
2551 {
2552 tree type = typetail ? TREE_VALUE (typetail) : 0;
2553 tree val = TREE_VALUE (valtail);
2554
2555 if (val == error_mark_node)
2556 return error_mark_node;
2557
2558 if (type == void_type_node)
2559 {
2560 if (fndecl)
2561 {
2562 cp_error_at ("too many arguments to %s `%+#D'", called_thing,
2563 fndecl);
2564 error ("at this point in file");
2565 }
2566 else
2567 error ("too many arguments to function");
2568 /* In case anybody wants to know if this argument
2569 list is valid. */
2570 if (result)
2571 TREE_TYPE (tree_last (result)) = error_mark_node;
2572 break;
2573 }
2574
2575 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2576 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */
2577 if (TREE_CODE (val) == NOP_EXPR
2578 && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0))
2579 && (type == 0 || TREE_CODE (type) != REFERENCE_TYPE))
2580 val = TREE_OPERAND (val, 0);
2581
2582 if (type == 0 || TREE_CODE (type) != REFERENCE_TYPE)
2583 {
2584 if (TREE_CODE (TREE_TYPE (val)) == ARRAY_TYPE
2585 || TREE_CODE (TREE_TYPE (val)) == FUNCTION_TYPE
2586 || TREE_CODE (TREE_TYPE (val)) == METHOD_TYPE)
2587 val = decay_conversion (val);
2588 }
2589
2590 if (val == error_mark_node)
2591 return error_mark_node;
2592
2593 if (type != 0)
2594 {
2595 /* Formal parm type is specified by a function prototype. */
2596 tree parmval;
2597
2598 if (!COMPLETE_TYPE_P (complete_type (type)))
2599 {
2600 if (fndecl)
2601 error ("parameter %P of `%D' has incomplete type `%T'",
2602 i, fndecl, type);
2603 else
2604 error ("parameter %P has incomplete type `%T'", i, type);
2605 parmval = error_mark_node;
2606 }
2607 else
2608 {
2609 parmval = convert_for_initialization
2610 (NULL_TREE, type, val, flags,
2611 "argument passing", fndecl, i);
2612 parmval = convert_for_arg_passing (type, parmval);
2613 }
2614
2615 if (parmval == error_mark_node)
2616 return error_mark_node;
2617
2618 result = tree_cons (NULL_TREE, parmval, result);
2619 }
2620 else
2621 {
2622 if (TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE)
2623 val = convert_from_reference (val);
2624
2625 if (fndecl && DECL_BUILT_IN (fndecl)
2626 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P)
2627 /* Don't do ellipsis conversion for __built_in_constant_p
2628 as this will result in spurious warnings for non-POD
2629 types. */
2630 val = require_complete_type (val);
2631 else
2632 val = convert_arg_to_ellipsis (val);
2633
2634 result = tree_cons (NULL_TREE, val, result);
2635 }
2636
2637 if (typetail)
2638 typetail = TREE_CHAIN (typetail);
2639 }
2640
2641 if (typetail != 0 && typetail != void_list_node)
2642 {
2643 /* See if there are default arguments that can be used. */
2644 if (TREE_PURPOSE (typetail)
2645 && TREE_CODE (TREE_PURPOSE (typetail)) != DEFAULT_ARG)
2646 {
2647 for (; typetail != void_list_node; ++i)
2648 {
2649 tree parmval
2650 = convert_default_arg (TREE_VALUE (typetail),
2651 TREE_PURPOSE (typetail),
2652 fndecl, i);
2653
2654 if (parmval == error_mark_node)
2655 return error_mark_node;
2656
2657 result = tree_cons (0, parmval, result);
2658 typetail = TREE_CHAIN (typetail);
2659 /* ends with `...'. */
2660 if (typetail == NULL_TREE)
2661 break;
2662 }
2663 }
2664 else
2665 {
2666 if (fndecl)
2667 {
2668 cp_error_at ("too few arguments to %s `%+#D'",
2669 called_thing, fndecl);
2670 error ("at this point in file");
2671 }
2672 else
2673 error ("too few arguments to function");
2674 return error_mark_list;
2675 }
2676 }
2677
2678 return nreverse (result);
2679 }
2680
2681 /* Build a binary-operation expression, after performing default
2682 conversions on the operands. CODE is the kind of expression to build. */
2683
2684 tree
build_x_binary_op(enum tree_code code,tree arg1,tree arg2,bool * overloaded_p)2685 build_x_binary_op (enum tree_code code, tree arg1, tree arg2,
2686 bool *overloaded_p)
2687 {
2688 tree orig_arg1;
2689 tree orig_arg2;
2690 tree expr;
2691
2692 orig_arg1 = arg1;
2693 orig_arg2 = arg2;
2694
2695 if (processing_template_decl)
2696 {
2697 if (type_dependent_expression_p (arg1)
2698 || type_dependent_expression_p (arg2))
2699 return build_min_nt (code, arg1, arg2);
2700 arg1 = build_non_dependent_expr (arg1);
2701 arg2 = build_non_dependent_expr (arg2);
2702 }
2703
2704 if (code == DOTSTAR_EXPR)
2705 expr = build_m_component_ref (arg1, arg2);
2706 else
2707 expr = build_new_op (code, LOOKUP_NORMAL, arg1, arg2, NULL_TREE,
2708 overloaded_p);
2709
2710 if (processing_template_decl && expr != error_mark_node)
2711 return build_min_non_dep (code, expr, orig_arg1, orig_arg2);
2712
2713 return expr;
2714 }
2715
2716 /* Build a binary-operation expression without default conversions.
2717 CODE is the kind of expression to build.
2718 This function differs from `build' in several ways:
2719 the data type of the result is computed and recorded in it,
2720 warnings are generated if arg data types are invalid,
2721 special handling for addition and subtraction of pointers is known,
2722 and some optimization is done (operations on narrow ints
2723 are done in the narrower type when that gives the same result).
2724 Constant folding is also done before the result is returned.
2725
2726 Note that the operands will never have enumeral types
2727 because either they have just had the default conversions performed
2728 or they have both just been converted to some other type in which
2729 the arithmetic is to be done.
2730
2731 C++: must do special pointer arithmetic when implementing
2732 multiple inheritance, and deal with pointer to member functions. */
2733
2734 tree
build_binary_op(enum tree_code code,tree orig_op0,tree orig_op1,int convert_p ATTRIBUTE_UNUSED)2735 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
2736 int convert_p ATTRIBUTE_UNUSED)
2737 {
2738 tree op0, op1;
2739 enum tree_code code0, code1;
2740 tree type0, type1;
2741
2742 /* Expression code to give to the expression when it is built.
2743 Normally this is CODE, which is what the caller asked for,
2744 but in some special cases we change it. */
2745 enum tree_code resultcode = code;
2746
2747 /* Data type in which the computation is to be performed.
2748 In the simplest cases this is the common type of the arguments. */
2749 tree result_type = NULL;
2750
2751 /* Nonzero means operands have already been type-converted
2752 in whatever way is necessary.
2753 Zero means they need to be converted to RESULT_TYPE. */
2754 int converted = 0;
2755
2756 /* Nonzero means create the expression with this type, rather than
2757 RESULT_TYPE. */
2758 tree build_type = 0;
2759
2760 /* Nonzero means after finally constructing the expression
2761 convert it to this type. */
2762 tree final_type = 0;
2763
2764 /* Nonzero if this is an operation like MIN or MAX which can
2765 safely be computed in short if both args are promoted shorts.
2766 Also implies COMMON.
2767 -1 indicates a bitwise operation; this makes a difference
2768 in the exact conditions for when it is safe to do the operation
2769 in a narrower mode. */
2770 int shorten = 0;
2771
2772 /* Nonzero if this is a comparison operation;
2773 if both args are promoted shorts, compare the original shorts.
2774 Also implies COMMON. */
2775 int short_compare = 0;
2776
2777 /* Nonzero if this is a right-shift operation, which can be computed on the
2778 original short and then promoted if the operand is a promoted short. */
2779 int short_shift = 0;
2780
2781 /* Nonzero means set RESULT_TYPE to the common type of the args. */
2782 int common = 0;
2783
2784 /* Apply default conversions. */
2785 op0 = orig_op0;
2786 op1 = orig_op1;
2787
2788 if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
2789 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
2790 || code == TRUTH_XOR_EXPR)
2791 {
2792 if (!really_overloaded_fn (op0))
2793 op0 = decay_conversion (op0);
2794 if (!really_overloaded_fn (op1))
2795 op1 = decay_conversion (op1);
2796 }
2797 else
2798 {
2799 if (!really_overloaded_fn (op0))
2800 op0 = default_conversion (op0);
2801 if (!really_overloaded_fn (op1))
2802 op1 = default_conversion (op1);
2803 }
2804
2805 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
2806 STRIP_TYPE_NOPS (op0);
2807 STRIP_TYPE_NOPS (op1);
2808
2809 /* DTRT if one side is an overloaded function, but complain about it. */
2810 if (type_unknown_p (op0))
2811 {
2812 tree t = instantiate_type (TREE_TYPE (op1), op0, tf_none);
2813 if (t != error_mark_node)
2814 {
2815 pedwarn ("assuming cast to type `%T' from overloaded function",
2816 TREE_TYPE (t));
2817 op0 = t;
2818 }
2819 }
2820 if (type_unknown_p (op1))
2821 {
2822 tree t = instantiate_type (TREE_TYPE (op0), op1, tf_none);
2823 if (t != error_mark_node)
2824 {
2825 pedwarn ("assuming cast to type `%T' from overloaded function",
2826 TREE_TYPE (t));
2827 op1 = t;
2828 }
2829 }
2830
2831 type0 = TREE_TYPE (op0);
2832 type1 = TREE_TYPE (op1);
2833
2834 /* The expression codes of the data types of the arguments tell us
2835 whether the arguments are integers, floating, pointers, etc. */
2836 code0 = TREE_CODE (type0);
2837 code1 = TREE_CODE (type1);
2838
2839 /* If an error was already reported for one of the arguments,
2840 avoid reporting another error. */
2841
2842 if (code0 == ERROR_MARK || code1 == ERROR_MARK)
2843 return error_mark_node;
2844
2845 switch (code)
2846 {
2847 case PLUS_EXPR:
2848 /* Handle the pointer + int case. */
2849 if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
2850 return cp_pointer_int_sum (PLUS_EXPR, op0, op1);
2851 else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
2852 return cp_pointer_int_sum (PLUS_EXPR, op1, op0);
2853 else
2854 common = 1;
2855 break;
2856
2857 case MINUS_EXPR:
2858 /* Subtraction of two similar pointers.
2859 We must subtract them as integers, then divide by object size. */
2860 if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
2861 && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type0),
2862 TREE_TYPE (type1)))
2863 return pointer_diff (op0, op1, common_type (type0, type1));
2864 /* Handle pointer minus int. Just like pointer plus int. */
2865 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
2866 return cp_pointer_int_sum (MINUS_EXPR, op0, op1);
2867 else
2868 common = 1;
2869 break;
2870
2871 case MULT_EXPR:
2872 common = 1;
2873 break;
2874
2875 case TRUNC_DIV_EXPR:
2876 case CEIL_DIV_EXPR:
2877 case FLOOR_DIV_EXPR:
2878 case ROUND_DIV_EXPR:
2879 case EXACT_DIV_EXPR:
2880 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
2881 || code0 == COMPLEX_TYPE)
2882 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
2883 || code1 == COMPLEX_TYPE))
2884 {
2885 if (TREE_CODE (op1) == INTEGER_CST && integer_zerop (op1))
2886 warning ("division by zero in `%E / 0'", op0);
2887 else if (TREE_CODE (op1) == REAL_CST && real_zerop (op1))
2888 warning ("division by zero in `%E / 0.'", op0);
2889
2890 if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
2891 resultcode = RDIV_EXPR;
2892 else
2893 /* When dividing two signed integers, we have to promote to int.
2894 unless we divide by a constant != -1. Note that default
2895 conversion will have been performed on the operands at this
2896 point, so we have to dig out the original type to find out if
2897 it was unsigned. */
2898 shorten = ((TREE_CODE (op0) == NOP_EXPR
2899 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0))))
2900 || (TREE_CODE (op1) == INTEGER_CST
2901 && ! integer_all_onesp (op1)));
2902
2903 common = 1;
2904 }
2905 break;
2906
2907 case BIT_AND_EXPR:
2908 case BIT_IOR_EXPR:
2909 case BIT_XOR_EXPR:
2910 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2911 shorten = -1;
2912 break;
2913
2914 case TRUNC_MOD_EXPR:
2915 case FLOOR_MOD_EXPR:
2916 if (code1 == INTEGER_TYPE && integer_zerop (op1))
2917 warning ("division by zero in `%E %% 0'", op0);
2918 else if (code1 == REAL_TYPE && real_zerop (op1))
2919 warning ("division by zero in `%E %% 0.'", op0);
2920
2921 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2922 {
2923 /* Although it would be tempting to shorten always here, that loses
2924 on some targets, since the modulo instruction is undefined if the
2925 quotient can't be represented in the computation mode. We shorten
2926 only if unsigned or if dividing by something we know != -1. */
2927 shorten = ((TREE_CODE (op0) == NOP_EXPR
2928 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0))))
2929 || (TREE_CODE (op1) == INTEGER_CST
2930 && ! integer_all_onesp (op1)));
2931 common = 1;
2932 }
2933 break;
2934
2935 case TRUTH_ANDIF_EXPR:
2936 case TRUTH_ORIF_EXPR:
2937 case TRUTH_AND_EXPR:
2938 case TRUTH_OR_EXPR:
2939 result_type = boolean_type_node;
2940 break;
2941
2942 /* Shift operations: result has same type as first operand;
2943 always convert second operand to int.
2944 Also set SHORT_SHIFT if shifting rightward. */
2945
2946 case RSHIFT_EXPR:
2947 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2948 {
2949 result_type = type0;
2950 if (TREE_CODE (op1) == INTEGER_CST)
2951 {
2952 if (tree_int_cst_lt (op1, integer_zero_node))
2953 warning ("right shift count is negative");
2954 else
2955 {
2956 if (! integer_zerop (op1))
2957 short_shift = 1;
2958 if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
2959 warning ("right shift count >= width of type");
2960 }
2961 }
2962 /* Convert the shift-count to an integer, regardless of
2963 size of value being shifted. */
2964 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
2965 op1 = cp_convert (integer_type_node, op1);
2966 /* Avoid converting op1 to result_type later. */
2967 converted = 1;
2968 }
2969 break;
2970
2971 case LSHIFT_EXPR:
2972 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2973 {
2974 result_type = type0;
2975 if (TREE_CODE (op1) == INTEGER_CST)
2976 {
2977 if (tree_int_cst_lt (op1, integer_zero_node))
2978 warning ("left shift count is negative");
2979 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
2980 warning ("left shift count >= width of type");
2981 }
2982 /* Convert the shift-count to an integer, regardless of
2983 size of value being shifted. */
2984 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
2985 op1 = cp_convert (integer_type_node, op1);
2986 /* Avoid converting op1 to result_type later. */
2987 converted = 1;
2988 }
2989 break;
2990
2991 case RROTATE_EXPR:
2992 case LROTATE_EXPR:
2993 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2994 {
2995 result_type = type0;
2996 if (TREE_CODE (op1) == INTEGER_CST)
2997 {
2998 if (tree_int_cst_lt (op1, integer_zero_node))
2999 warning ("%s rotate count is negative",
3000 (code == LROTATE_EXPR) ? "left" : "right");
3001 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
3002 warning ("%s rotate count >= width of type",
3003 (code == LROTATE_EXPR) ? "left" : "right");
3004 }
3005 /* Convert the shift-count to an integer, regardless of
3006 size of value being shifted. */
3007 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
3008 op1 = cp_convert (integer_type_node, op1);
3009 }
3010 break;
3011
3012 case EQ_EXPR:
3013 case NE_EXPR:
3014 if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
3015 warning ("comparing floating point with == or != is unsafe");
3016
3017 build_type = boolean_type_node;
3018 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
3019 || code0 == COMPLEX_TYPE)
3020 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
3021 || code1 == COMPLEX_TYPE))
3022 short_compare = 1;
3023 else if ((code0 == POINTER_TYPE && code1 == POINTER_TYPE)
3024 || (TYPE_PTRMEM_P (type0) && TYPE_PTRMEM_P (type1)))
3025 result_type = composite_pointer_type (type0, type1, op0, op1,
3026 "comparison");
3027 else if ((code0 == POINTER_TYPE || TYPE_PTRMEM_P (type0))
3028 && null_ptr_cst_p (op1))
3029 result_type = type0;
3030 else if ((code1 == POINTER_TYPE || TYPE_PTRMEM_P (type1))
3031 && null_ptr_cst_p (op0))
3032 result_type = type1;
3033 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
3034 {
3035 result_type = type0;
3036 error ("ISO C++ forbids comparison between pointer and integer");
3037 }
3038 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
3039 {
3040 result_type = type1;
3041 error ("ISO C++ forbids comparison between pointer and integer");
3042 }
3043 else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (op1))
3044 {
3045 op0 = build_ptrmemfunc_access_expr (op0, pfn_identifier);
3046 op1 = cp_convert (TREE_TYPE (op0), integer_zero_node);
3047 result_type = TREE_TYPE (op0);
3048 }
3049 else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (op0))
3050 return cp_build_binary_op (code, op1, op0);
3051 else if (TYPE_PTRMEMFUNC_P (type0) && TYPE_PTRMEMFUNC_P (type1)
3052 && same_type_p (type0, type1))
3053 {
3054 /* E will be the final comparison. */
3055 tree e;
3056 /* E1 and E2 are for scratch. */
3057 tree e1;
3058 tree e2;
3059 tree pfn0;
3060 tree pfn1;
3061 tree delta0;
3062 tree delta1;
3063
3064 if (TREE_SIDE_EFFECTS (op0))
3065 op0 = save_expr (op0);
3066 if (TREE_SIDE_EFFECTS (op1))
3067 op1 = save_expr (op1);
3068
3069 /* We generate:
3070
3071 (op0.pfn == op1.pfn
3072 && (!op0.pfn || op0.delta == op1.delta))
3073
3074 The reason for the `!op0.pfn' bit is that a NULL
3075 pointer-to-member is any member with a zero PFN; the
3076 DELTA field is unspecified. */
3077 pfn0 = pfn_from_ptrmemfunc (op0);
3078 pfn1 = pfn_from_ptrmemfunc (op1);
3079 delta0 = build_ptrmemfunc_access_expr (op0,
3080 delta_identifier);
3081 delta1 = build_ptrmemfunc_access_expr (op1,
3082 delta_identifier);
3083 e1 = cp_build_binary_op (EQ_EXPR, delta0, delta1);
3084 e2 = cp_build_binary_op (EQ_EXPR,
3085 pfn0,
3086 cp_convert (TREE_TYPE (pfn0),
3087 integer_zero_node));
3088 e1 = cp_build_binary_op (TRUTH_ORIF_EXPR, e1, e2);
3089 e2 = build (EQ_EXPR, boolean_type_node, pfn0, pfn1);
3090 e = cp_build_binary_op (TRUTH_ANDIF_EXPR, e2, e1);
3091 if (code == EQ_EXPR)
3092 return e;
3093 return cp_build_binary_op (EQ_EXPR, e, integer_zero_node);
3094 }
3095 else if ((TYPE_PTRMEMFUNC_P (type0)
3096 && same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type0), type1))
3097 || (TYPE_PTRMEMFUNC_P (type1)
3098 && same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type1), type0)))
3099 abort ();
3100 break;
3101
3102 case MAX_EXPR:
3103 case MIN_EXPR:
3104 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
3105 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
3106 shorten = 1;
3107 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
3108 result_type = composite_pointer_type (type0, type1, op0, op1,
3109 "comparison");
3110 break;
3111
3112 case LE_EXPR:
3113 case GE_EXPR:
3114 case LT_EXPR:
3115 case GT_EXPR:
3116 build_type = boolean_type_node;
3117 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
3118 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
3119 short_compare = 1;
3120 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
3121 result_type = composite_pointer_type (type0, type1, op0, op1,
3122 "comparison");
3123 else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
3124 && integer_zerop (op1))
3125 result_type = type0;
3126 else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
3127 && integer_zerop (op0))
3128 result_type = type1;
3129 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
3130 {
3131 result_type = type0;
3132 pedwarn ("ISO C++ forbids comparison between pointer and integer");
3133 }
3134 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
3135 {
3136 result_type = type1;
3137 pedwarn ("ISO C++ forbids comparison between pointer and integer");
3138 }
3139 break;
3140
3141 case UNORDERED_EXPR:
3142 case ORDERED_EXPR:
3143 case UNLT_EXPR:
3144 case UNLE_EXPR:
3145 case UNGT_EXPR:
3146 case UNGE_EXPR:
3147 case UNEQ_EXPR:
3148 build_type = integer_type_node;
3149 if (code0 != REAL_TYPE || code1 != REAL_TYPE)
3150 {
3151 error ("unordered comparison on non-floating point argument");
3152 return error_mark_node;
3153 }
3154 common = 1;
3155 break;
3156
3157 default:
3158 break;
3159 }
3160
3161 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
3162 &&
3163 (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
3164 {
3165 int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
3166
3167 if (shorten || common || short_compare)
3168 result_type = common_type (type0, type1);
3169
3170 /* For certain operations (which identify themselves by shorten != 0)
3171 if both args were extended from the same smaller type,
3172 do the arithmetic in that type and then extend.
3173
3174 shorten !=0 and !=1 indicates a bitwise operation.
3175 For them, this optimization is safe only if
3176 both args are zero-extended or both are sign-extended.
3177 Otherwise, we might change the result.
3178 Eg, (short)-1 | (unsigned short)-1 is (int)-1
3179 but calculated in (unsigned short) it would be (unsigned short)-1. */
3180
3181 if (shorten && none_complex)
3182 {
3183 int unsigned0, unsigned1;
3184 tree arg0 = get_narrower (op0, &unsigned0);
3185 tree arg1 = get_narrower (op1, &unsigned1);
3186 /* UNS is 1 if the operation to be done is an unsigned one. */
3187 int uns = TREE_UNSIGNED (result_type);
3188 tree type;
3189
3190 final_type = result_type;
3191
3192 /* Handle the case that OP0 does not *contain* a conversion
3193 but it *requires* conversion to FINAL_TYPE. */
3194
3195 if (op0 == arg0 && TREE_TYPE (op0) != final_type)
3196 unsigned0 = TREE_UNSIGNED (TREE_TYPE (op0));
3197 if (op1 == arg1 && TREE_TYPE (op1) != final_type)
3198 unsigned1 = TREE_UNSIGNED (TREE_TYPE (op1));
3199
3200 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
3201
3202 /* For bitwise operations, signedness of nominal type
3203 does not matter. Consider only how operands were extended. */
3204 if (shorten == -1)
3205 uns = unsigned0;
3206
3207 /* Note that in all three cases below we refrain from optimizing
3208 an unsigned operation on sign-extended args.
3209 That would not be valid. */
3210
3211 /* Both args variable: if both extended in same way
3212 from same width, do it in that width.
3213 Do it unsigned if args were zero-extended. */
3214 if ((TYPE_PRECISION (TREE_TYPE (arg0))
3215 < TYPE_PRECISION (result_type))
3216 && (TYPE_PRECISION (TREE_TYPE (arg1))
3217 == TYPE_PRECISION (TREE_TYPE (arg0)))
3218 && unsigned0 == unsigned1
3219 && (unsigned0 || !uns))
3220 result_type = c_common_signed_or_unsigned_type
3221 (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
3222 else if (TREE_CODE (arg0) == INTEGER_CST
3223 && (unsigned1 || !uns)
3224 && (TYPE_PRECISION (TREE_TYPE (arg1))
3225 < TYPE_PRECISION (result_type))
3226 && (type = c_common_signed_or_unsigned_type
3227 (unsigned1, TREE_TYPE (arg1)),
3228 int_fits_type_p (arg0, type)))
3229 result_type = type;
3230 else if (TREE_CODE (arg1) == INTEGER_CST
3231 && (unsigned0 || !uns)
3232 && (TYPE_PRECISION (TREE_TYPE (arg0))
3233 < TYPE_PRECISION (result_type))
3234 && (type = c_common_signed_or_unsigned_type
3235 (unsigned0, TREE_TYPE (arg0)),
3236 int_fits_type_p (arg1, type)))
3237 result_type = type;
3238 }
3239
3240 /* Shifts can be shortened if shifting right. */
3241
3242 if (short_shift)
3243 {
3244 int unsigned_arg;
3245 tree arg0 = get_narrower (op0, &unsigned_arg);
3246
3247 final_type = result_type;
3248
3249 if (arg0 == op0 && final_type == TREE_TYPE (op0))
3250 unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0));
3251
3252 if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
3253 /* We can shorten only if the shift count is less than the
3254 number of bits in the smaller type size. */
3255 && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
3256 /* If arg is sign-extended and then unsigned-shifted,
3257 we can simulate this with a signed shift in arg's type
3258 only if the extended result is at least twice as wide
3259 as the arg. Otherwise, the shift could use up all the
3260 ones made by sign-extension and bring in zeros.
3261 We can't optimize that case at all, but in most machines
3262 it never happens because available widths are 2**N. */
3263 && (!TREE_UNSIGNED (final_type)
3264 || unsigned_arg
3265 || (((unsigned) 2 * TYPE_PRECISION (TREE_TYPE (arg0)))
3266 <= TYPE_PRECISION (result_type))))
3267 {
3268 /* Do an unsigned shift if the operand was zero-extended. */
3269 result_type
3270 = c_common_signed_or_unsigned_type (unsigned_arg,
3271 TREE_TYPE (arg0));
3272 /* Convert value-to-be-shifted to that type. */
3273 if (TREE_TYPE (op0) != result_type)
3274 op0 = cp_convert (result_type, op0);
3275 converted = 1;
3276 }
3277 }
3278
3279 /* Comparison operations are shortened too but differently.
3280 They identify themselves by setting short_compare = 1. */
3281
3282 if (short_compare)
3283 {
3284 /* Don't write &op0, etc., because that would prevent op0
3285 from being kept in a register.
3286 Instead, make copies of the our local variables and
3287 pass the copies by reference, then copy them back afterward. */
3288 tree xop0 = op0, xop1 = op1, xresult_type = result_type;
3289 enum tree_code xresultcode = resultcode;
3290 tree val
3291 = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
3292 if (val != 0)
3293 return cp_convert (boolean_type_node, val);
3294 op0 = xop0, op1 = xop1;
3295 converted = 1;
3296 resultcode = xresultcode;
3297 }
3298
3299 if ((short_compare || code == MIN_EXPR || code == MAX_EXPR)
3300 && warn_sign_compare
3301 /* Do not warn until the template is instantiated; we cannot
3302 bound the ranges of the arguments until that point. */
3303 && !processing_template_decl)
3304 {
3305 int op0_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op0));
3306 int op1_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op1));
3307
3308 int unsignedp0, unsignedp1;
3309 tree primop0 = get_narrower (op0, &unsignedp0);
3310 tree primop1 = get_narrower (op1, &unsignedp1);
3311
3312 /* Check for comparison of different enum types. */
3313 if (TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE
3314 && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE
3315 && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0))
3316 != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1)))
3317 {
3318 warning ("comparison between types `%#T' and `%#T'",
3319 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1));
3320 }
3321
3322 /* Give warnings for comparisons between signed and unsigned
3323 quantities that may fail. */
3324 /* Do the checking based on the original operand trees, so that
3325 casts will be considered, but default promotions won't be. */
3326
3327 /* Do not warn if the comparison is being done in a signed type,
3328 since the signed type will only be chosen if it can represent
3329 all the values of the unsigned type. */
3330 if (! TREE_UNSIGNED (result_type))
3331 /* OK */;
3332 /* Do not warn if both operands are unsigned. */
3333 else if (op0_signed == op1_signed)
3334 /* OK */;
3335 /* Do not warn if the signed quantity is an unsuffixed
3336 integer literal (or some static constant expression
3337 involving such literals or a conditional expression
3338 involving such literals) and it is non-negative. */
3339 else if ((op0_signed && tree_expr_nonnegative_p (orig_op0))
3340 || (op1_signed && tree_expr_nonnegative_p (orig_op1)))
3341 /* OK */;
3342 /* Do not warn if the comparison is an equality operation,
3343 the unsigned quantity is an integral constant and it does
3344 not use the most significant bit of result_type. */
3345 else if ((resultcode == EQ_EXPR || resultcode == NE_EXPR)
3346 && ((op0_signed && TREE_CODE (orig_op1) == INTEGER_CST
3347 && int_fits_type_p (orig_op1, c_common_signed_type
3348 (result_type)))
3349 || (op1_signed && TREE_CODE (orig_op0) == INTEGER_CST
3350 && int_fits_type_p (orig_op0, c_common_signed_type
3351 (result_type)))))
3352 /* OK */;
3353 else
3354 warning ("comparison between signed and unsigned integer expressions");
3355
3356 /* Warn if two unsigned values are being compared in a size
3357 larger than their original size, and one (and only one) is the
3358 result of a `~' operator. This comparison will always fail.
3359
3360 Also warn if one operand is a constant, and the constant does not
3361 have all bits set that are set in the ~ operand when it is
3362 extended. */
3363
3364 if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
3365 ^ (TREE_CODE (primop1) == BIT_NOT_EXPR))
3366 {
3367 if (TREE_CODE (primop0) == BIT_NOT_EXPR)
3368 primop0 = get_narrower (TREE_OPERAND (op0, 0), &unsignedp0);
3369 if (TREE_CODE (primop1) == BIT_NOT_EXPR)
3370 primop1 = get_narrower (TREE_OPERAND (op1, 0), &unsignedp1);
3371
3372 if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
3373 {
3374 tree primop;
3375 HOST_WIDE_INT constant, mask;
3376 int unsignedp;
3377 unsigned int bits;
3378
3379 if (host_integerp (primop0, 0))
3380 {
3381 primop = primop1;
3382 unsignedp = unsignedp1;
3383 constant = tree_low_cst (primop0, 0);
3384 }
3385 else
3386 {
3387 primop = primop0;
3388 unsignedp = unsignedp0;
3389 constant = tree_low_cst (primop1, 0);
3390 }
3391
3392 bits = TYPE_PRECISION (TREE_TYPE (primop));
3393 if (bits < TYPE_PRECISION (result_type)
3394 && bits < HOST_BITS_PER_LONG && unsignedp)
3395 {
3396 mask = (~ (HOST_WIDE_INT) 0) << bits;
3397 if ((mask & constant) != mask)
3398 warning ("comparison of promoted ~unsigned with constant");
3399 }
3400 }
3401 else if (unsignedp0 && unsignedp1
3402 && (TYPE_PRECISION (TREE_TYPE (primop0))
3403 < TYPE_PRECISION (result_type))
3404 && (TYPE_PRECISION (TREE_TYPE (primop1))
3405 < TYPE_PRECISION (result_type)))
3406 warning ("comparison of promoted ~unsigned with unsigned");
3407 }
3408 }
3409 }
3410
3411 /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
3412 If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
3413 Then the expression will be built.
3414 It will be given type FINAL_TYPE if that is nonzero;
3415 otherwise, it will be given type RESULT_TYPE. */
3416
3417 if (!result_type)
3418 {
3419 error ("invalid operands of types `%T' and `%T' to binary `%O'",
3420 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1), code);
3421 return error_mark_node;
3422 }
3423
3424 /* Issue warnings about peculiar, but valid, uses of NULL. */
3425 if (/* It's reasonable to use pointer values as operands of &&
3426 and ||, so NULL is no exception. */
3427 !(code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR)
3428 && (/* If OP0 is NULL and OP1 is not a pointer, or vice versa. */
3429 (orig_op0 == null_node
3430 && TREE_CODE (TREE_TYPE (op1)) != POINTER_TYPE)
3431 /* Or vice versa. */
3432 || (orig_op1 == null_node
3433 && TREE_CODE (TREE_TYPE (op0)) != POINTER_TYPE)
3434 /* Or, both are NULL and the operation was not a comparison. */
3435 || (orig_op0 == null_node && orig_op1 == null_node
3436 && code != EQ_EXPR && code != NE_EXPR)))
3437 /* Some sort of arithmetic operation involving NULL was
3438 performed. Note that pointer-difference and pointer-addition
3439 have already been handled above, and so we don't end up here in
3440 that case. */
3441 warning ("NULL used in arithmetic");
3442
3443 if (! converted)
3444 {
3445 if (TREE_TYPE (op0) != result_type)
3446 op0 = cp_convert (result_type, op0);
3447 if (TREE_TYPE (op1) != result_type)
3448 op1 = cp_convert (result_type, op1);
3449
3450 if (op0 == error_mark_node || op1 == error_mark_node)
3451 return error_mark_node;
3452 }
3453
3454 if (build_type == NULL_TREE)
3455 build_type = result_type;
3456
3457 {
3458 tree result = build (resultcode, build_type, op0, op1);
3459 tree folded;
3460
3461 folded = fold (result);
3462 if (folded == result)
3463 TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
3464 if (final_type != 0)
3465 return cp_convert (final_type, folded);
3466 return folded;
3467 }
3468 }
3469
3470 /* Return a tree for the sum or difference (RESULTCODE says which)
3471 of pointer PTROP and integer INTOP. */
3472
3473 static tree
cp_pointer_int_sum(enum tree_code resultcode,tree ptrop,tree intop)3474 cp_pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop)
3475 {
3476 tree res_type = TREE_TYPE (ptrop);
3477
3478 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type)
3479 in certain circumstance (when it's valid to do so). So we need
3480 to make sure it's complete. We don't need to check here, if we
3481 can actually complete it at all, as those checks will be done in
3482 pointer_int_sum() anyway. */
3483 complete_type (TREE_TYPE (res_type));
3484
3485 return pointer_int_sum (resultcode, ptrop, fold (intop));
3486 }
3487
3488 /* Return a tree for the difference of pointers OP0 and OP1.
3489 The resulting tree has type int. */
3490
3491 static tree
pointer_diff(tree op0,tree op1,tree ptrtype)3492 pointer_diff (tree op0, tree op1, tree ptrtype)
3493 {
3494 tree result, folded;
3495 tree restype = ptrdiff_type_node;
3496 tree target_type = TREE_TYPE (ptrtype);
3497
3498 if (!complete_type_or_else (target_type, NULL_TREE))
3499 return error_mark_node;
3500
3501 if (pedantic || warn_pointer_arith)
3502 {
3503 if (TREE_CODE (target_type) == VOID_TYPE)
3504 pedwarn ("ISO C++ forbids using pointer of type `void *' in subtraction");
3505 if (TREE_CODE (target_type) == FUNCTION_TYPE)
3506 pedwarn ("ISO C++ forbids using pointer to a function in subtraction");
3507 if (TREE_CODE (target_type) == METHOD_TYPE)
3508 pedwarn ("ISO C++ forbids using pointer to a method in subtraction");
3509 }
3510
3511 /* First do the subtraction as integers;
3512 then drop through to build the divide operator. */
3513
3514 op0 = cp_build_binary_op (MINUS_EXPR,
3515 cp_convert (restype, op0),
3516 cp_convert (restype, op1));
3517
3518 /* This generates an error if op1 is a pointer to an incomplete type. */
3519 if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (op1))))
3520 error ("invalid use of a pointer to an incomplete type in pointer arithmetic");
3521
3522 op1 = (TYPE_PTROB_P (ptrtype)
3523 ? size_in_bytes (target_type)
3524 : integer_one_node);
3525
3526 /* Do the division. */
3527
3528 result = build (EXACT_DIV_EXPR, restype, op0, cp_convert (restype, op1));
3529
3530 folded = fold (result);
3531 if (folded == result)
3532 TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
3533 return folded;
3534 }
3535
3536 /* Construct and perhaps optimize a tree representation
3537 for a unary operation. CODE, a tree_code, specifies the operation
3538 and XARG is the operand. */
3539
3540 tree
build_x_unary_op(enum tree_code code,tree xarg)3541 build_x_unary_op (enum tree_code code, tree xarg)
3542 {
3543 tree orig_expr = xarg;
3544 tree exp;
3545 int ptrmem = 0;
3546
3547 if (processing_template_decl)
3548 {
3549 if (type_dependent_expression_p (xarg))
3550 return build_min_nt (code, xarg, NULL_TREE);
3551
3552 /* For non-dependent pointer-to-member, the SCOPE_REF will be
3553 processed during template substitution. Just compute the
3554 right type here and build an ADDR_EXPR around it for
3555 diagnostics. */
3556 if (code == ADDR_EXPR && TREE_CODE (xarg) == SCOPE_REF)
3557 {
3558 tree type;
3559 if (TREE_TYPE (xarg) == unknown_type_node)
3560 type = unknown_type_node;
3561 else if (TREE_CODE (TREE_TYPE (xarg)) == FUNCTION_TYPE)
3562 type = build_pointer_type (TREE_TYPE (xarg));
3563 else
3564 type = build_ptrmem_type (TREE_OPERAND (xarg, 0),
3565 TREE_TYPE (xarg));
3566 return build_min (code, type, xarg, NULL_TREE);
3567 }
3568
3569 xarg = build_non_dependent_expr (xarg);
3570 }
3571
3572 exp = NULL_TREE;
3573
3574 /* [expr.unary.op] says:
3575
3576 The address of an object of incomplete type can be taken.
3577
3578 (And is just the ordinary address operator, not an overloaded
3579 "operator &".) However, if the type is a template
3580 specialization, we must complete the type at this point so that
3581 an overloaded "operator &" will be available if required. */
3582 if (code == ADDR_EXPR
3583 && TREE_CODE (xarg) != TEMPLATE_ID_EXPR
3584 && ((CLASS_TYPE_P (TREE_TYPE (xarg))
3585 && !COMPLETE_TYPE_P (complete_type (TREE_TYPE (xarg))))
3586 || (TREE_CODE (xarg) == OFFSET_REF)))
3587 /* Don't look for a function. */;
3588 else
3589 exp = build_new_op (code, LOOKUP_NORMAL, xarg, NULL_TREE, NULL_TREE,
3590 /*overloaded_p=*/NULL);
3591 if (!exp && code == ADDR_EXPR)
3592 {
3593 /* A pointer to member-function can be formed only by saying
3594 &X::mf. */
3595 if (!flag_ms_extensions && TREE_CODE (TREE_TYPE (xarg)) == METHOD_TYPE
3596 && (TREE_CODE (xarg) != OFFSET_REF || !PTRMEM_OK_P (xarg)))
3597 {
3598 if (TREE_CODE (xarg) != OFFSET_REF)
3599 {
3600 error ("invalid use of '%E' to form a pointer-to-member-function. Use a qualified-id.",
3601 xarg);
3602 return error_mark_node;
3603 }
3604 else
3605 {
3606 error ("parenthesis around '%E' cannot be used to form a pointer-to-member-function",
3607 xarg);
3608 PTRMEM_OK_P (xarg) = 1;
3609 }
3610 }
3611
3612 if (TREE_CODE (xarg) == OFFSET_REF)
3613 {
3614 ptrmem = PTRMEM_OK_P (xarg);
3615
3616 if (!ptrmem && !flag_ms_extensions
3617 && TREE_CODE (TREE_TYPE (TREE_OPERAND (xarg, 1))) == METHOD_TYPE)
3618 {
3619 /* A single non-static member, make sure we don't allow a
3620 pointer-to-member. */
3621 xarg = build (OFFSET_REF, TREE_TYPE (xarg),
3622 TREE_OPERAND (xarg, 0),
3623 ovl_cons (TREE_OPERAND (xarg, 1), NULL_TREE));
3624 PTRMEM_OK_P (xarg) = ptrmem;
3625 }
3626 }
3627 else if (TREE_CODE (xarg) == TARGET_EXPR)
3628 warning ("taking address of temporary");
3629 exp = build_unary_op (ADDR_EXPR, xarg, 0);
3630 if (TREE_CODE (exp) == ADDR_EXPR)
3631 PTRMEM_OK_P (exp) = ptrmem;
3632 }
3633
3634 if (processing_template_decl && exp != error_mark_node)
3635 return build_min_non_dep (code, exp, orig_expr,
3636 /*For {PRE,POST}{INC,DEC}REMENT_EXPR*/NULL_TREE);
3637 return exp;
3638 }
3639
3640 /* Like c_common_truthvalue_conversion, but handle pointer-to-member
3641 constants, where a null value is represented by an INTEGER_CST of
3642 -1. */
3643
3644 tree
cp_truthvalue_conversion(tree expr)3645 cp_truthvalue_conversion (tree expr)
3646 {
3647 tree type = TREE_TYPE (expr);
3648 if (TYPE_PTRMEM_P (type))
3649 return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
3650 else
3651 return c_common_truthvalue_conversion (expr);
3652 }
3653
3654 /* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */
3655
3656 tree
condition_conversion(tree expr)3657 condition_conversion (tree expr)
3658 {
3659 tree t;
3660 if (processing_template_decl)
3661 return expr;
3662 t = perform_implicit_conversion (boolean_type_node, expr);
3663 t = fold (build1 (CLEANUP_POINT_EXPR, boolean_type_node, t));
3664 return t;
3665 }
3666
3667 /* Return an ADDR_EXPR giving the address of T. This function
3668 attempts no optimizations or simplifications; it is a low-level
3669 primitive. */
3670
3671 tree
build_address(tree t)3672 build_address (tree t)
3673 {
3674 tree addr;
3675
3676 if (error_operand_p (t) || !cxx_mark_addressable (t))
3677 return error_mark_node;
3678
3679 addr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (t)), t);
3680 if (staticp (t))
3681 TREE_CONSTANT (addr) = 1;
3682
3683 return addr;
3684 }
3685
3686 /* Return a NOP_EXPR converting EXPR to TYPE. */
3687
3688 tree
build_nop(tree type,tree expr)3689 build_nop (tree type, tree expr)
3690 {
3691 tree nop;
3692
3693 if (type == error_mark_node || error_operand_p (expr))
3694 return expr;
3695
3696 nop = build1 (NOP_EXPR, type, expr);
3697 if (TREE_CONSTANT (expr))
3698 TREE_CONSTANT (nop) = 1;
3699
3700 return nop;
3701 }
3702
3703 /* C++: Must handle pointers to members.
3704
3705 Perhaps type instantiation should be extended to handle conversion
3706 from aggregates to types we don't yet know we want? (Or are those
3707 cases typically errors which should be reported?)
3708
3709 NOCONVERT nonzero suppresses the default promotions
3710 (such as from short to int). */
3711
3712 tree
build_unary_op(enum tree_code code,tree xarg,int noconvert)3713 build_unary_op (enum tree_code code, tree xarg, int noconvert)
3714 {
3715 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
3716 tree arg = xarg;
3717 tree argtype = 0;
3718 const char *errstring = NULL;
3719 tree val;
3720
3721 if (arg == error_mark_node)
3722 return error_mark_node;
3723
3724 switch (code)
3725 {
3726 case CONVERT_EXPR:
3727 /* This is used for unary plus, because a CONVERT_EXPR
3728 is enough to prevent anybody from looking inside for
3729 associativity, but won't generate any code. */
3730 if (!(arg = build_expr_type_conversion
3731 (WANT_ARITH | WANT_ENUM | WANT_POINTER, arg, true)))
3732 errstring = "wrong type argument to unary plus";
3733 else
3734 {
3735 if (!noconvert)
3736 arg = default_conversion (arg);
3737 arg = build1 (NON_LVALUE_EXPR, TREE_TYPE (arg), arg);
3738 TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3739 }
3740 break;
3741
3742 case NEGATE_EXPR:
3743 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3744 errstring = "wrong type argument to unary minus";
3745 else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg)))
3746 arg = perform_integral_promotions (arg);
3747 break;
3748
3749 case BIT_NOT_EXPR:
3750 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3751 {
3752 code = CONJ_EXPR;
3753 if (!noconvert)
3754 arg = default_conversion (arg);
3755 }
3756 else if (!(arg = build_expr_type_conversion (WANT_INT | WANT_ENUM,
3757 arg, true)))
3758 errstring = "wrong type argument to bit-complement";
3759 else if (!noconvert)
3760 arg = perform_integral_promotions (arg);
3761 break;
3762
3763 case ABS_EXPR:
3764 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3765 errstring = "wrong type argument to abs";
3766 else if (!noconvert)
3767 arg = default_conversion (arg);
3768 break;
3769
3770 case CONJ_EXPR:
3771 /* Conjugating a real value is a no-op, but allow it anyway. */
3772 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3773 errstring = "wrong type argument to conjugation";
3774 else if (!noconvert)
3775 arg = default_conversion (arg);
3776 break;
3777
3778 case TRUTH_NOT_EXPR:
3779 arg = perform_implicit_conversion (boolean_type_node, arg);
3780 val = invert_truthvalue (arg);
3781 if (arg != error_mark_node)
3782 return val;
3783 errstring = "in argument to unary !";
3784 break;
3785
3786 case NOP_EXPR:
3787 break;
3788
3789 case REALPART_EXPR:
3790 if (TREE_CODE (arg) == COMPLEX_CST)
3791 return TREE_REALPART (arg);
3792 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3793 return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
3794 else
3795 return arg;
3796
3797 case IMAGPART_EXPR:
3798 if (TREE_CODE (arg) == COMPLEX_CST)
3799 return TREE_IMAGPART (arg);
3800 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3801 return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
3802 else
3803 return cp_convert (TREE_TYPE (arg), integer_zero_node);
3804
3805 case PREINCREMENT_EXPR:
3806 case POSTINCREMENT_EXPR:
3807 case PREDECREMENT_EXPR:
3808 case POSTDECREMENT_EXPR:
3809 /* Handle complex lvalues (when permitted)
3810 by reduction to simpler cases. */
3811
3812 val = unary_complex_lvalue (code, arg);
3813 if (val != 0)
3814 return val;
3815
3816 /* Increment or decrement the real part of the value,
3817 and don't change the imaginary part. */
3818 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3819 {
3820 tree real, imag;
3821
3822 arg = stabilize_reference (arg);
3823 real = build_unary_op (REALPART_EXPR, arg, 1);
3824 imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3825 return build (COMPLEX_EXPR, TREE_TYPE (arg),
3826 build_unary_op (code, real, 1), imag);
3827 }
3828
3829 /* Report invalid types. */
3830
3831 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_POINTER,
3832 arg, true)))
3833 {
3834 if (code == PREINCREMENT_EXPR)
3835 errstring ="no pre-increment operator for type";
3836 else if (code == POSTINCREMENT_EXPR)
3837 errstring ="no post-increment operator for type";
3838 else if (code == PREDECREMENT_EXPR)
3839 errstring ="no pre-decrement operator for type";
3840 else
3841 errstring ="no post-decrement operator for type";
3842 break;
3843 }
3844
3845 /* Report something read-only. */
3846
3847 if (CP_TYPE_CONST_P (TREE_TYPE (arg))
3848 || TREE_READONLY (arg))
3849 readonly_error (arg, ((code == PREINCREMENT_EXPR
3850 || code == POSTINCREMENT_EXPR)
3851 ? "increment" : "decrement"),
3852 0);
3853
3854 {
3855 tree inc;
3856 tree result_type = TREE_TYPE (arg);
3857
3858 arg = get_unwidened (arg, 0);
3859 argtype = TREE_TYPE (arg);
3860
3861 /* ARM $5.2.5 last annotation says this should be forbidden. */
3862 if (TREE_CODE (argtype) == ENUMERAL_TYPE)
3863 pedwarn ("ISO C++ forbids %sing an enum",
3864 (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3865 ? "increment" : "decrement");
3866
3867 /* Compute the increment. */
3868
3869 if (TREE_CODE (argtype) == POINTER_TYPE)
3870 {
3871 tree type = complete_type (TREE_TYPE (argtype));
3872
3873 if (!COMPLETE_OR_VOID_TYPE_P (type))
3874 error ("cannot %s a pointer to incomplete type `%T'",
3875 ((code == PREINCREMENT_EXPR
3876 || code == POSTINCREMENT_EXPR)
3877 ? "increment" : "decrement"), TREE_TYPE (argtype));
3878 else if ((pedantic || warn_pointer_arith)
3879 && !TYPE_PTROB_P (argtype))
3880 pedwarn ("ISO C++ forbids %sing a pointer of type `%T'",
3881 ((code == PREINCREMENT_EXPR
3882 || code == POSTINCREMENT_EXPR)
3883 ? "increment" : "decrement"), argtype);
3884 inc = cxx_sizeof_nowarn (TREE_TYPE (argtype));
3885 }
3886 else
3887 inc = integer_one_node;
3888
3889 inc = cp_convert (argtype, inc);
3890
3891 /* Handle incrementing a cast-expression. */
3892
3893 switch (TREE_CODE (arg))
3894 {
3895 case NOP_EXPR:
3896 case CONVERT_EXPR:
3897 case FLOAT_EXPR:
3898 case FIX_TRUNC_EXPR:
3899 case FIX_FLOOR_EXPR:
3900 case FIX_ROUND_EXPR:
3901 case FIX_CEIL_EXPR:
3902 {
3903 tree incremented, modify, value, compound;
3904 if (! lvalue_p (arg) && pedantic)
3905 pedwarn ("cast to non-reference type used as lvalue");
3906 arg = stabilize_reference (arg);
3907 if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR)
3908 value = arg;
3909 else
3910 value = save_expr (arg);
3911 incremented = build (((code == PREINCREMENT_EXPR
3912 || code == POSTINCREMENT_EXPR)
3913 ? PLUS_EXPR : MINUS_EXPR),
3914 argtype, value, inc);
3915
3916 modify = build_modify_expr (arg, NOP_EXPR, incremented);
3917 compound = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value);
3918
3919 /* Eliminate warning about unused result of + or -. */
3920 TREE_NO_UNUSED_WARNING (compound) = 1;
3921 return compound;
3922 }
3923
3924 default:
3925 break;
3926 }
3927
3928 /* Complain about anything else that is not a true lvalue. */
3929 if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3930 || code == POSTINCREMENT_EXPR)
3931 ? "increment" : "decrement")))
3932 return error_mark_node;
3933
3934 /* Forbid using -- on `bool'. */
3935 if (TREE_TYPE (arg) == boolean_type_node)
3936 {
3937 if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR)
3938 {
3939 error ("invalid use of `--' on bool variable `%D'", arg);
3940 return error_mark_node;
3941 }
3942 val = boolean_increment (code, arg);
3943 }
3944 else
3945 val = build (code, TREE_TYPE (arg), arg, inc);
3946
3947 TREE_SIDE_EFFECTS (val) = 1;
3948 return cp_convert (result_type, val);
3949 }
3950
3951 case ADDR_EXPR:
3952 /* Note that this operation never does default_conversion
3953 regardless of NOCONVERT. */
3954
3955 argtype = lvalue_type (arg);
3956
3957 if (TREE_CODE (arg) == OFFSET_REF)
3958 goto offset_ref;
3959
3960 if (TREE_CODE (argtype) == REFERENCE_TYPE)
3961 {
3962 arg = build1
3963 (CONVERT_EXPR,
3964 build_pointer_type (TREE_TYPE (argtype)), arg);
3965 TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3966 return arg;
3967 }
3968 else if (pedantic && DECL_MAIN_P (arg))
3969 /* ARM $3.4 */
3970 pedwarn ("ISO C++ forbids taking address of function `::main'");
3971
3972 /* Let &* cancel out to simplify resulting code. */
3973 if (TREE_CODE (arg) == INDIRECT_REF)
3974 {
3975 /* We don't need to have `current_class_ptr' wrapped in a
3976 NON_LVALUE_EXPR node. */
3977 if (arg == current_class_ref)
3978 return current_class_ptr;
3979
3980 arg = TREE_OPERAND (arg, 0);
3981 if (TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE)
3982 {
3983 arg = build1
3984 (CONVERT_EXPR,
3985 build_pointer_type (TREE_TYPE (TREE_TYPE (arg))), arg);
3986 TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3987 }
3988 else if (lvalue_p (arg))
3989 /* Don't let this be an lvalue. */
3990 return non_lvalue (arg);
3991 return arg;
3992 }
3993
3994 /* For &x[y], return x+y. But, in a template, ARG may be an
3995 ARRAY_REF representing a non-dependent expression. In that
3996 case, there may be an overloaded "operator []" that will be
3997 chosen at instantiation time; we must not try to optimize
3998 here. */
3999 if (TREE_CODE (arg) == ARRAY_REF && !processing_template_decl)
4000 {
4001 if (!cxx_mark_addressable (TREE_OPERAND (arg, 0)))
4002 return error_mark_node;
4003 return cp_build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
4004 TREE_OPERAND (arg, 1));
4005 }
4006
4007 /* Uninstantiated types are all functions. Taking the
4008 address of a function is a no-op, so just return the
4009 argument. */
4010
4011 if (TREE_CODE (arg) == IDENTIFIER_NODE
4012 && IDENTIFIER_OPNAME_P (arg))
4013 {
4014 abort ();
4015 /* We don't know the type yet, so just work around the problem.
4016 We know that this will resolve to an lvalue. */
4017 return build1 (ADDR_EXPR, unknown_type_node, arg);
4018 }
4019
4020 if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg)
4021 && !really_overloaded_fn (TREE_OPERAND (arg, 1)))
4022 {
4023 /* They're trying to take the address of a unique non-static
4024 member function. This is ill-formed (except in MS-land),
4025 but let's try to DTRT.
4026 Note: We only handle unique functions here because we don't
4027 want to complain if there's a static overload; non-unique
4028 cases will be handled by instantiate_type. But we need to
4029 handle this case here to allow casts on the resulting PMF.
4030 We could defer this in non-MS mode, but it's easier to give
4031 a useful error here. */
4032
4033 /* Inside constant member functions, the `this' pointer
4034 contains an extra const qualifier. TYPE_MAIN_VARIANT
4035 is used here to remove this const from the diagnostics
4036 and the created OFFSET_REF. */
4037 tree base = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (arg, 0)));
4038 tree name = DECL_NAME (get_first_fn (TREE_OPERAND (arg, 1)));
4039
4040 if (! flag_ms_extensions)
4041 {
4042 if (current_class_type
4043 && TREE_OPERAND (arg, 0) == current_class_ref)
4044 /* An expression like &memfn. */
4045 pedwarn ("ISO C++ forbids taking the address of an unqualified"
4046 " or parenthesized non-static member function to form"
4047 " a pointer to member function. Say `&%T::%D'",
4048 base, name);
4049 else
4050 pedwarn ("ISO C++ forbids taking the address of a bound member"
4051 " function to form a pointer to member function."
4052 " Say `&%T::%D'",
4053 base, name);
4054 }
4055 arg = build_offset_ref (base, name, /*address_p=*/true);
4056 }
4057
4058 offset_ref:
4059 if (type_unknown_p (arg))
4060 return build1 (ADDR_EXPR, unknown_type_node, arg);
4061
4062 /* Handle complex lvalues (when permitted)
4063 by reduction to simpler cases. */
4064 val = unary_complex_lvalue (code, arg);
4065 if (val != 0)
4066 return val;
4067
4068 switch (TREE_CODE (arg))
4069 {
4070 case NOP_EXPR:
4071 case CONVERT_EXPR:
4072 case FLOAT_EXPR:
4073 case FIX_TRUNC_EXPR:
4074 case FIX_FLOOR_EXPR:
4075 case FIX_ROUND_EXPR:
4076 case FIX_CEIL_EXPR:
4077 if (! lvalue_p (arg) && pedantic)
4078 pedwarn ("ISO C++ forbids taking the address of a cast to a non-lvalue expression");
4079 break;
4080
4081 case OVERLOAD:
4082 arg = OVL_CURRENT (arg);
4083 break;
4084
4085 default:
4086 break;
4087 }
4088
4089 /* Allow the address of a constructor if all the elements
4090 are constant. */
4091 if (TREE_CODE (arg) == CONSTRUCTOR && TREE_HAS_CONSTRUCTOR (arg)
4092 && TREE_CONSTANT (arg))
4093 ;
4094 /* Anything not already handled and not a true memory reference
4095 is an error. */
4096 else if (TREE_CODE (argtype) != FUNCTION_TYPE
4097 && TREE_CODE (argtype) != METHOD_TYPE
4098 && !lvalue_or_else (arg, "unary `&'"))
4099 return error_mark_node;
4100
4101 if (argtype != error_mark_node)
4102 argtype = build_pointer_type (argtype);
4103
4104 {
4105 tree addr;
4106
4107 if (TREE_CODE (arg) != COMPONENT_REF
4108 /* Inside a template, we are processing a non-dependent
4109 expression so we can just form an ADDR_EXPR with the
4110 correct type. */
4111 || processing_template_decl)
4112 addr = build_address (arg);
4113 else if (TREE_CODE (TREE_OPERAND (arg, 1)) == BASELINK)
4114 {
4115 tree fn = BASELINK_FUNCTIONS (TREE_OPERAND (arg, 1));
4116
4117 /* We can only get here with a single static member
4118 function. */
4119 my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL
4120 && DECL_STATIC_FUNCTION_P (fn),
4121 20030906);
4122 mark_used (fn);
4123 addr = build_address (fn);
4124 if (TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0)))
4125 /* Do not lose object's side effects. */
4126 addr = build (COMPOUND_EXPR, TREE_TYPE (addr),
4127 TREE_OPERAND (arg, 0), addr);
4128 }
4129 else if (DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)))
4130 {
4131 error ("attempt to take address of bit-field structure member `%D'",
4132 TREE_OPERAND (arg, 1));
4133 return error_mark_node;
4134 }
4135 else
4136 {
4137 /* Unfortunately we cannot just build an address
4138 expression here, because we would not handle
4139 address-constant-expressions or offsetof correctly. */
4140 tree field = TREE_OPERAND (arg, 1);
4141 tree rval = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), 0);
4142 tree binfo = lookup_base (TREE_TYPE (TREE_TYPE (rval)),
4143 decl_type_context (field),
4144 ba_check, NULL);
4145
4146 rval = build_base_path (PLUS_EXPR, rval, binfo, 1);
4147 rval = build_nop (argtype, rval);
4148 addr = fold (build (PLUS_EXPR, argtype, rval,
4149 cp_convert (argtype, byte_position (field))));
4150 }
4151
4152 if (TREE_CODE (argtype) == POINTER_TYPE
4153 && TREE_CODE (TREE_TYPE (argtype)) == METHOD_TYPE)
4154 {
4155 build_ptrmemfunc_type (argtype);
4156 addr = build_ptrmemfunc (argtype, addr, 0);
4157 }
4158
4159 return addr;
4160 }
4161
4162 default:
4163 break;
4164 }
4165
4166 if (!errstring)
4167 {
4168 if (argtype == 0)
4169 argtype = TREE_TYPE (arg);
4170 return fold (build1 (code, argtype, arg));
4171 }
4172
4173 error ("%s", errstring);
4174 return error_mark_node;
4175 }
4176
4177 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4178 for certain kinds of expressions which are not really lvalues
4179 but which we can accept as lvalues.
4180
4181 If ARG is not a kind of expression we can handle, return zero. */
4182
4183 tree
unary_complex_lvalue(enum tree_code code,tree arg)4184 unary_complex_lvalue (enum tree_code code, tree arg)
4185 {
4186 /* Handle (a, b) used as an "lvalue". */
4187 if (TREE_CODE (arg) == COMPOUND_EXPR)
4188 {
4189 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0);
4190 return build (COMPOUND_EXPR, TREE_TYPE (real_result),
4191 TREE_OPERAND (arg, 0), real_result);
4192 }
4193
4194 /* Handle (a ? b : c) used as an "lvalue". */
4195 if (TREE_CODE (arg) == COND_EXPR
4196 || TREE_CODE (arg) == MIN_EXPR || TREE_CODE (arg) == MAX_EXPR)
4197 return rationalize_conditional_expr (code, arg);
4198
4199 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */
4200 if (TREE_CODE (arg) == MODIFY_EXPR
4201 || TREE_CODE (arg) == PREINCREMENT_EXPR
4202 || TREE_CODE (arg) == PREDECREMENT_EXPR)
4203 {
4204 tree lvalue = TREE_OPERAND (arg, 0);
4205 if (TREE_SIDE_EFFECTS (lvalue))
4206 {
4207 lvalue = stabilize_reference (lvalue);
4208 arg = build (TREE_CODE (arg), TREE_TYPE (arg),
4209 lvalue, TREE_OPERAND (arg, 1));
4210 }
4211 return unary_complex_lvalue
4212 (code, build (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue));
4213 }
4214
4215 if (code != ADDR_EXPR)
4216 return 0;
4217
4218 /* Handle (a = b) used as an "lvalue" for `&'. */
4219 if (TREE_CODE (arg) == MODIFY_EXPR
4220 || TREE_CODE (arg) == INIT_EXPR)
4221 {
4222 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 0), 0);
4223 arg = build (COMPOUND_EXPR, TREE_TYPE (real_result), arg, real_result);
4224 TREE_NO_UNUSED_WARNING (arg) = 1;
4225 return arg;
4226 }
4227
4228 if (TREE_CODE (TREE_TYPE (arg)) == FUNCTION_TYPE
4229 || TREE_CODE (TREE_TYPE (arg)) == METHOD_TYPE
4230 || TREE_CODE (arg) == OFFSET_REF)
4231 {
4232 tree t;
4233
4234 my_friendly_assert (TREE_CODE (arg) != SCOPE_REF, 313);
4235
4236 if (TREE_CODE (arg) != OFFSET_REF)
4237 return 0;
4238
4239 t = TREE_OPERAND (arg, 1);
4240
4241 /* Check all this code for right semantics. */
4242 if (TREE_CODE (t) == FUNCTION_DECL)
4243 {
4244 if (DECL_DESTRUCTOR_P (t))
4245 error ("taking address of destructor");
4246 return build_unary_op (ADDR_EXPR, t, 0);
4247 }
4248 if (TREE_CODE (t) == VAR_DECL)
4249 return build_unary_op (ADDR_EXPR, t, 0);
4250 else
4251 {
4252 tree type;
4253
4254 if (TREE_OPERAND (arg, 0)
4255 && ! is_dummy_object (TREE_OPERAND (arg, 0))
4256 && TREE_CODE (t) != FIELD_DECL)
4257 {
4258 error ("taking address of bound pointer-to-member expression");
4259 return error_mark_node;
4260 }
4261 if (!PTRMEM_OK_P (arg))
4262 return build_unary_op (code, arg, 0);
4263
4264 if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE)
4265 {
4266 error ("cannot create pointer to reference member `%D'", t);
4267 return error_mark_node;
4268 }
4269
4270 type = build_ptrmem_type (context_for_name_lookup (t),
4271 TREE_TYPE (t));
4272 t = make_ptrmem_cst (type, TREE_OPERAND (arg, 1));
4273 return t;
4274 }
4275 }
4276
4277
4278 /* We permit compiler to make function calls returning
4279 objects of aggregate type look like lvalues. */
4280 {
4281 tree targ = arg;
4282
4283 if (TREE_CODE (targ) == SAVE_EXPR)
4284 targ = TREE_OPERAND (targ, 0);
4285
4286 if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (TREE_TYPE (targ)))
4287 {
4288 if (TREE_CODE (arg) == SAVE_EXPR)
4289 targ = arg;
4290 else
4291 targ = build_cplus_new (TREE_TYPE (arg), arg);
4292 return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (arg)), targ);
4293 }
4294
4295 if (TREE_CODE (arg) == SAVE_EXPR && TREE_CODE (targ) == INDIRECT_REF)
4296 return build (SAVE_EXPR, build_pointer_type (TREE_TYPE (arg)),
4297 TREE_OPERAND (targ, 0), current_function_decl, NULL);
4298 }
4299
4300 /* Don't let anything else be handled specially. */
4301 return 0;
4302 }
4303
4304 /* Mark EXP saying that we need to be able to take the
4305 address of it; it should not be allocated in a register.
4306 Value is true if successful.
4307
4308 C++: we do not allow `current_class_ptr' to be addressable. */
4309
4310 bool
cxx_mark_addressable(tree exp)4311 cxx_mark_addressable (tree exp)
4312 {
4313 tree x = exp;
4314
4315 while (1)
4316 switch (TREE_CODE (x))
4317 {
4318 case ADDR_EXPR:
4319 case COMPONENT_REF:
4320 case ARRAY_REF:
4321 case REALPART_EXPR:
4322 case IMAGPART_EXPR:
4323 x = TREE_OPERAND (x, 0);
4324 break;
4325
4326 case PARM_DECL:
4327 if (x == current_class_ptr)
4328 {
4329 error ("cannot take the address of `this', which is an rvalue expression");
4330 TREE_ADDRESSABLE (x) = 1; /* so compiler doesn't die later. */
4331 return true;
4332 }
4333 /* Fall through. */
4334
4335 case VAR_DECL:
4336 /* Caller should not be trying to mark initialized
4337 constant fields addressable. */
4338 my_friendly_assert (DECL_LANG_SPECIFIC (x) == 0
4339 || DECL_IN_AGGR_P (x) == 0
4340 || TREE_STATIC (x)
4341 || DECL_EXTERNAL (x), 314);
4342 /* Fall through. */
4343
4344 case CONST_DECL:
4345 case RESULT_DECL:
4346 if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x)
4347 && !DECL_ARTIFICIAL (x) && extra_warnings)
4348 warning ("address requested for `%D', which is declared `register'",
4349 x);
4350 TREE_ADDRESSABLE (x) = 1;
4351 put_var_into_stack (x, /*rescan=*/true);
4352 return true;
4353
4354 case FUNCTION_DECL:
4355 TREE_ADDRESSABLE (x) = 1;
4356 TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (x)) = 1;
4357 return true;
4358
4359 case CONSTRUCTOR:
4360 TREE_ADDRESSABLE (x) = 1;
4361 return true;
4362
4363 case TARGET_EXPR:
4364 TREE_ADDRESSABLE (x) = 1;
4365 cxx_mark_addressable (TREE_OPERAND (x, 0));
4366 return true;
4367
4368 default:
4369 return true;
4370 }
4371 }
4372
4373 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
4374
4375 tree
build_x_conditional_expr(tree ifexp,tree op1,tree op2)4376 build_x_conditional_expr (tree ifexp, tree op1, tree op2)
4377 {
4378 tree orig_ifexp = ifexp;
4379 tree orig_op1 = op1;
4380 tree orig_op2 = op2;
4381 tree expr;
4382
4383 if (processing_template_decl)
4384 {
4385 /* The standard says that the expression is type-dependent if
4386 IFEXP is type-dependent, even though the eventual type of the
4387 expression doesn't dependent on IFEXP. */
4388 if (type_dependent_expression_p (ifexp)
4389 /* As a GNU extension, the middle operand may be omitted. */
4390 || (op1 && type_dependent_expression_p (op1))
4391 || type_dependent_expression_p (op2))
4392 return build_min_nt (COND_EXPR, ifexp, op1, op2);
4393 ifexp = build_non_dependent_expr (ifexp);
4394 if (op1)
4395 op1 = build_non_dependent_expr (op1);
4396 op2 = build_non_dependent_expr (op2);
4397 }
4398
4399 expr = build_conditional_expr (ifexp, op1, op2);
4400 if (processing_template_decl && expr != error_mark_node)
4401 return build_min_non_dep (COND_EXPR, expr,
4402 orig_ifexp, orig_op1, orig_op2);
4403 return expr;
4404 }
4405
4406 /* Given a list of expressions, return a compound expression
4407 that performs them all and returns the value of the last of them. */
4408
build_x_compound_expr_from_list(tree list,const char * msg)4409 tree build_x_compound_expr_from_list (tree list, const char *msg)
4410 {
4411 tree expr = TREE_VALUE (list);
4412
4413 if (TREE_CHAIN (list))
4414 {
4415 if (msg)
4416 pedwarn ("%s expression list treated as compound expression", msg);
4417
4418 for (list = TREE_CHAIN (list); list; list = TREE_CHAIN (list))
4419 expr = build_x_compound_expr (expr, TREE_VALUE (list));
4420 }
4421
4422 return expr;
4423 }
4424
4425 /* Handle overloading of the ',' operator when needed. */
4426
4427 tree
build_x_compound_expr(tree op1,tree op2)4428 build_x_compound_expr (tree op1, tree op2)
4429 {
4430 tree result;
4431 tree orig_op1 = op1;
4432 tree orig_op2 = op2;
4433
4434 if (processing_template_decl)
4435 {
4436 if (type_dependent_expression_p (op1)
4437 || type_dependent_expression_p (op2))
4438 return build_min_nt (COMPOUND_EXPR, op1, op2);
4439 op1 = build_non_dependent_expr (op1);
4440 op2 = build_non_dependent_expr (op2);
4441 }
4442
4443 result = build_new_op (COMPOUND_EXPR, LOOKUP_NORMAL, op1, op2, NULL_TREE,
4444 /*overloaded_p=*/NULL);
4445 if (!result)
4446 result = build_compound_expr (op1, op2);
4447
4448 if (processing_template_decl && result != error_mark_node)
4449 return build_min_non_dep (COMPOUND_EXPR, result, orig_op1, orig_op2);
4450
4451 return result;
4452 }
4453
4454 /* Build a compound expression. */
4455
4456 tree
build_compound_expr(tree lhs,tree rhs)4457 build_compound_expr (tree lhs, tree rhs)
4458 {
4459 lhs = decl_constant_value (lhs);
4460 lhs = convert_to_void (lhs, "left-hand operand of comma");
4461
4462 if (lhs == error_mark_node || rhs == error_mark_node)
4463 return error_mark_node;
4464
4465 if (TREE_CODE (rhs) == TARGET_EXPR)
4466 {
4467 /* If the rhs is a TARGET_EXPR, then build the compound
4468 expression inside the target_expr's initializer. This
4469 helps the compiler to eliminate unnecessary temporaries. */
4470 tree init = TREE_OPERAND (rhs, 1);
4471
4472 init = build (COMPOUND_EXPR, TREE_TYPE (init), lhs, init);
4473 TREE_OPERAND (rhs, 1) = init;
4474
4475 return rhs;
4476 }
4477
4478 return build (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs);
4479 }
4480
4481 /* Issue an error message if casting from SRC_TYPE to DEST_TYPE casts
4482 away constness. DESCRIPTION explains what operation is taking
4483 place. */
4484
4485 static void
check_for_casting_away_constness(tree src_type,tree dest_type,const char * description)4486 check_for_casting_away_constness (tree src_type, tree dest_type,
4487 const char *description)
4488 {
4489 if (casts_away_constness (src_type, dest_type))
4490 error ("%s from type `%T' to type `%T' casts away constness",
4491 description, src_type, dest_type);
4492 }
4493
4494 /* Return an expression representing static_cast<TYPE>(EXPR). */
4495
4496 tree
build_static_cast(tree type,tree expr)4497 build_static_cast (tree type, tree expr)
4498 {
4499 tree intype;
4500 tree result;
4501
4502 if (type == error_mark_node || expr == error_mark_node)
4503 return error_mark_node;
4504
4505 if (processing_template_decl)
4506 {
4507 expr = build_min (STATIC_CAST_EXPR, type, expr);
4508 /* We don't know if it will or will not have side effects. */
4509 TREE_SIDE_EFFECTS (expr) = 1;
4510 return expr;
4511 }
4512
4513 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4514 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4515 if (TREE_CODE (type) != REFERENCE_TYPE
4516 && TREE_CODE (expr) == NOP_EXPR
4517 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4518 expr = TREE_OPERAND (expr, 0);
4519
4520 intype = TREE_TYPE (expr);
4521
4522 /* [expr.static.cast]
4523
4524 An lvalue of type "cv1 B", where B is a class type, can be cast
4525 to type "reference to cv2 D", where D is a class derived (clause
4526 _class.derived_) from B, if a valid standard conversion from
4527 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the
4528 same cv-qualification as, or greater cv-qualification than, cv1,
4529 and B is not a virtual base class of D. */
4530 /* We check this case before checking the validity of "TYPE t =
4531 EXPR;" below because for this case:
4532
4533 struct B {};
4534 struct D : public B { D(const B&); };
4535 extern B& b;
4536 void f() { static_cast<const D&>(b); }
4537
4538 we want to avoid constructing a new D. The standard is not
4539 completely clear about this issue, but our interpretation is
4540 consistent with other compilers. */
4541 if (TREE_CODE (type) == REFERENCE_TYPE
4542 && CLASS_TYPE_P (TREE_TYPE (type))
4543 && CLASS_TYPE_P (intype)
4544 && real_lvalue_p (expr)
4545 && DERIVED_FROM_P (intype, TREE_TYPE (type))
4546 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT (intype)),
4547 build_pointer_type (TYPE_MAIN_VARIANT
4548 (TREE_TYPE (type))))
4549 && at_least_as_qualified_p (TREE_TYPE (type), intype))
4550 {
4551 /* There is a standard conversion from "D*" to "B*" even if "B"
4552 is ambiguous or inaccessible. Therefore, we ask lookup_base
4553 to check these conditions. */
4554 tree base = lookup_base (TREE_TYPE (type), intype, ba_check, NULL);
4555
4556 /* Convert from "B*" to "D*". This function will check that "B"
4557 is not a virtual base of "D". */
4558 expr = build_base_path (MINUS_EXPR, build_address (expr),
4559 base, /*nonnull=*/false);
4560 /* Convert the pointer to a reference -- but then remember that
4561 there are no expressions with reference type in C++. */
4562 return convert_from_reference (build_nop (type, expr));
4563 }
4564
4565 /* [expr.static.cast]
4566
4567 An expression e can be explicitly converted to a type T using a
4568 static_cast of the form static_cast<T>(e) if the declaration T
4569 t(e);" is well-formed, for some invented temporary variable
4570 t. */
4571 result = perform_direct_initialization_if_possible (type, expr);
4572 if (result)
4573 {
4574 result = convert_from_reference (result);
4575 /* [expr.static.cast]
4576
4577 If T is a reference type, the result is an lvalue; otherwise,
4578 the result is an rvalue. */
4579 if (TREE_CODE (type) != REFERENCE_TYPE
4580 && real_lvalue_p (result))
4581 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (result), result);
4582 return result;
4583 }
4584
4585 /* [expr.static.cast]
4586
4587 Any expression can be explicitly converted to type cv void. */
4588 if (TREE_CODE (type) == VOID_TYPE)
4589 return convert_to_void (expr, /*implicit=*/NULL);
4590
4591 /* [expr.static.cast]
4592
4593 The inverse of any standard conversion sequence (clause _conv_),
4594 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer
4595 (_conv.array_), function-to-pointer (_conv.func_), and boolean
4596 (_conv.bool_) conversions, can be performed explicitly using
4597 static_cast subject to the restriction that the explicit
4598 conversion does not cast away constness (_expr.const.cast_), and
4599 the following additional rules for specific cases: */
4600 /* For reference, the conversions not excluded are: integral
4601 promotions, floating point promotion, integral conversions,
4602 floating point conversions, floating-integral conversions,
4603 pointer conversions, and pointer to member conversions. */
4604 if ((ARITHMETIC_TYPE_P (type) && ARITHMETIC_TYPE_P (intype))
4605 /* DR 128
4606
4607 A value of integral _or enumeration_ type can be explicitly
4608 converted to an enumeration type. */
4609 || (INTEGRAL_OR_ENUMERATION_TYPE_P (type)
4610 && INTEGRAL_OR_ENUMERATION_TYPE_P (intype)))
4611 /* Really, build_c_cast should defer to this function rather
4612 than the other way around. */
4613 return build_c_cast (type, expr);
4614
4615 if (TYPE_PTR_P (type) && TYPE_PTR_P (intype)
4616 && CLASS_TYPE_P (TREE_TYPE (type))
4617 && CLASS_TYPE_P (TREE_TYPE (intype))
4618 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT
4619 (TREE_TYPE (intype))),
4620 build_pointer_type (TYPE_MAIN_VARIANT
4621 (TREE_TYPE (type)))))
4622 {
4623 tree base;
4624
4625 check_for_casting_away_constness (intype, type, "static_cast");
4626 base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), ba_check,
4627 NULL);
4628 return build_base_path (MINUS_EXPR, expr, base, /*nonnull=*/false);
4629 }
4630
4631 if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
4632 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
4633 {
4634 tree c1;
4635 tree c2;
4636 tree t1;
4637 tree t2;
4638
4639 c1 = TYPE_PTRMEM_CLASS_TYPE (intype);
4640 c2 = TYPE_PTRMEM_CLASS_TYPE (type);
4641
4642 if (TYPE_PTRMEM_P (type))
4643 {
4644 t1 = (build_ptrmem_type
4645 (c1,
4646 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (intype))));
4647 t2 = (build_ptrmem_type
4648 (c2,
4649 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (type))));
4650 }
4651 else
4652 {
4653 t1 = intype;
4654 t2 = type;
4655 }
4656 if (can_convert (t1, t2))
4657 {
4658 check_for_casting_away_constness (intype, type, "static_cast");
4659 if (TYPE_PTRMEM_P (type))
4660 {
4661 tree delta;
4662
4663 if (TREE_CODE (expr) == PTRMEM_CST)
4664 expr = cplus_expand_constant (expr);
4665 delta = get_delta_difference (c1, c2, /*force=*/1);
4666 if (!integer_zerop (delta))
4667 expr = cp_build_binary_op (PLUS_EXPR,
4668 build_nop (ptrdiff_type_node, expr),
4669 delta);
4670 return build_nop (type, expr);
4671 }
4672 else
4673 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr,
4674 /*force=*/1);
4675 }
4676 }
4677
4678 /* [expr.static.cast]
4679
4680 An rvalue of type "pointer to cv void" can be explicitly
4681 converted to a pointer to object type. A value of type pointer
4682 to object converted to "pointer to cv void" and back to the
4683 original pointer type will have its original value. */
4684 if (TREE_CODE (intype) == POINTER_TYPE
4685 && VOID_TYPE_P (TREE_TYPE (intype))
4686 && TYPE_PTROB_P (type))
4687 {
4688 check_for_casting_away_constness (intype, type, "static_cast");
4689 return build_nop (type, expr);
4690 }
4691
4692 error ("invalid static_cast from type `%T' to type `%T'", intype, type);
4693 return error_mark_node;
4694 }
4695
4696 tree
build_reinterpret_cast(tree type,tree expr)4697 build_reinterpret_cast (tree type, tree expr)
4698 {
4699 tree intype;
4700
4701 if (type == error_mark_node || expr == error_mark_node)
4702 return error_mark_node;
4703
4704 if (processing_template_decl)
4705 {
4706 tree t = build_min (REINTERPRET_CAST_EXPR, type, expr);
4707
4708 if (!TREE_SIDE_EFFECTS (t)
4709 && type_dependent_expression_p (expr))
4710 /* There might turn out to be side effects inside expr. */
4711 TREE_SIDE_EFFECTS (t) = 1;
4712 return t;
4713 }
4714
4715 if (TREE_CODE (type) != REFERENCE_TYPE)
4716 {
4717 expr = decay_conversion (expr);
4718
4719 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4720 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4721 if (TREE_CODE (expr) == NOP_EXPR
4722 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4723 expr = TREE_OPERAND (expr, 0);
4724 }
4725
4726 intype = TREE_TYPE (expr);
4727
4728 if (TREE_CODE (type) == REFERENCE_TYPE)
4729 {
4730 if (! real_lvalue_p (expr))
4731 {
4732 error ("invalid reinterpret_cast of an rvalue expression of type `%T' to type `%T'", intype, type);
4733 return error_mark_node;
4734 }
4735 expr = build_unary_op (ADDR_EXPR, expr, 0);
4736 if (expr != error_mark_node)
4737 expr = build_reinterpret_cast
4738 (build_pointer_type (TREE_TYPE (type)), expr);
4739 if (expr != error_mark_node)
4740 expr = build_indirect_ref (expr, 0);
4741 return expr;
4742 }
4743 else if (same_type_ignoring_top_level_qualifiers_p (intype, type))
4744 return build_static_cast (type, expr);
4745
4746 if (TYPE_PTR_P (type) && (TREE_CODE (intype) == INTEGER_TYPE
4747 || TREE_CODE (intype) == ENUMERAL_TYPE))
4748 /* OK */;
4749 else if (TREE_CODE (type) == INTEGER_TYPE && TYPE_PTR_P (intype))
4750 {
4751 if (TYPE_PRECISION (type) < TYPE_PRECISION (intype))
4752 pedwarn ("reinterpret_cast from `%T' to `%T' loses precision",
4753 intype, type);
4754 }
4755 else if ((TYPE_PTRFN_P (type) && TYPE_PTRFN_P (intype))
4756 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
4757 {
4758 expr = decl_constant_value (expr);
4759 return fold (build1 (NOP_EXPR, type, expr));
4760 }
4761 else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
4762 || (TYPE_PTROBV_P (type) && TYPE_PTROBV_P (intype)))
4763 {
4764 check_for_casting_away_constness (intype, type, "reinterpret_cast");
4765 expr = decl_constant_value (expr);
4766 return fold (build1 (NOP_EXPR, type, expr));
4767 }
4768 else if ((TYPE_PTRFN_P (type) && TYPE_PTROBV_P (intype))
4769 || (TYPE_PTRFN_P (intype) && TYPE_PTROBV_P (type)))
4770 {
4771 pedwarn ("ISO C++ forbids casting between pointer-to-function and pointer-to-object");
4772 expr = decl_constant_value (expr);
4773 return fold (build1 (NOP_EXPR, type, expr));
4774 }
4775 else
4776 {
4777 error ("invalid reinterpret_cast from type `%T' to type `%T'",
4778 intype, type);
4779 return error_mark_node;
4780 }
4781
4782 return cp_convert (type, expr);
4783 }
4784
4785 tree
build_const_cast(tree type,tree expr)4786 build_const_cast (tree type, tree expr)
4787 {
4788 tree intype;
4789
4790 if (type == error_mark_node || expr == error_mark_node)
4791 return error_mark_node;
4792
4793 if (processing_template_decl)
4794 {
4795 tree t = build_min (CONST_CAST_EXPR, type, expr);
4796
4797 if (!TREE_SIDE_EFFECTS (t)
4798 && type_dependent_expression_p (expr))
4799 /* There might turn out to be side effects inside expr. */
4800 TREE_SIDE_EFFECTS (t) = 1;
4801 return t;
4802 }
4803
4804 if (!POINTER_TYPE_P (type) && !TYPE_PTRMEM_P (type))
4805 error ("invalid use of const_cast with type `%T', which is not a pointer, reference, nor a pointer-to-data-member type", type);
4806 else if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4807 {
4808 error ("invalid use of const_cast with type `%T', which is a pointer or reference to a function type", type);
4809 return error_mark_node;
4810 }
4811
4812 if (TREE_CODE (type) != REFERENCE_TYPE)
4813 {
4814 expr = decay_conversion (expr);
4815
4816 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4817 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4818 if (TREE_CODE (expr) == NOP_EXPR
4819 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4820 expr = TREE_OPERAND (expr, 0);
4821 }
4822
4823 intype = TREE_TYPE (expr);
4824
4825 if (same_type_ignoring_top_level_qualifiers_p (intype, type))
4826 return build_static_cast (type, expr);
4827 else if (TREE_CODE (type) == REFERENCE_TYPE)
4828 {
4829 if (! real_lvalue_p (expr))
4830 {
4831 error ("invalid const_cast of an rvalue of type `%T' to type `%T'", intype, type);
4832 return error_mark_node;
4833 }
4834
4835 if (comp_ptr_ttypes_const (TREE_TYPE (type), intype))
4836 {
4837 expr = build_unary_op (ADDR_EXPR, expr, 0);
4838 expr = build1 (NOP_EXPR, type, expr);
4839 return convert_from_reference (expr);
4840 }
4841 }
4842 else if (((TREE_CODE (type) == POINTER_TYPE
4843 && TREE_CODE (intype) == POINTER_TYPE)
4844 || (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)))
4845 && comp_ptr_ttypes_const (TREE_TYPE (type), TREE_TYPE (intype)))
4846 return cp_convert (type, expr);
4847
4848 error ("invalid const_cast from type `%T' to type `%T'", intype, type);
4849 return error_mark_node;
4850 }
4851
4852 /* Build an expression representing a cast to type TYPE of expression EXPR.
4853
4854 ALLOW_NONCONVERTING is true if we should allow non-converting constructors
4855 when doing the cast. */
4856
4857 tree
build_c_cast(tree type,tree expr)4858 build_c_cast (tree type, tree expr)
4859 {
4860 tree value = expr;
4861 tree otype;
4862
4863 if (type == error_mark_node || expr == error_mark_node)
4864 return error_mark_node;
4865
4866 if (processing_template_decl)
4867 {
4868 tree t = build_min (CAST_EXPR, type,
4869 tree_cons (NULL_TREE, value, NULL_TREE));
4870 /* We don't know if it will or will not have side effects. */
4871 TREE_SIDE_EFFECTS (t) = 1;
4872 return t;
4873 }
4874
4875 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4876 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4877 if (TREE_CODE (type) != REFERENCE_TYPE
4878 && TREE_CODE (value) == NOP_EXPR
4879 && TREE_TYPE (value) == TREE_TYPE (TREE_OPERAND (value, 0)))
4880 value = TREE_OPERAND (value, 0);
4881
4882 if (TREE_CODE (type) == ARRAY_TYPE)
4883 {
4884 /* Allow casting from T1* to T2[] because Cfront allows it.
4885 NIHCL uses it. It is not valid ISO C++ however. */
4886 if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
4887 {
4888 pedwarn ("ISO C++ forbids casting to an array type `%T'", type);
4889 type = build_pointer_type (TREE_TYPE (type));
4890 }
4891 else
4892 {
4893 error ("ISO C++ forbids casting to an array type `%T'", type);
4894 return error_mark_node;
4895 }
4896 }
4897
4898 if (TREE_CODE (type) == FUNCTION_TYPE
4899 || TREE_CODE (type) == METHOD_TYPE)
4900 {
4901 error ("invalid cast to function type `%T'", type);
4902 return error_mark_node;
4903 }
4904
4905 if (TREE_CODE (type) == VOID_TYPE)
4906 {
4907 /* Conversion to void does not cause any of the normal function to
4908 * pointer, array to pointer and lvalue to rvalue decays. */
4909
4910 value = convert_to_void (value, /*implicit=*/NULL);
4911 return value;
4912 }
4913
4914 if (!complete_type_or_else (type, NULL_TREE))
4915 return error_mark_node;
4916
4917 /* Convert functions and arrays to pointers and
4918 convert references to their expanded types,
4919 but don't convert any other types. If, however, we are
4920 casting to a class type, there's no reason to do this: the
4921 cast will only succeed if there is a converting constructor,
4922 and the default conversions will be done at that point. In
4923 fact, doing the default conversion here is actually harmful
4924 in cases like this:
4925
4926 typedef int A[2];
4927 struct S { S(const A&); };
4928
4929 since we don't want the array-to-pointer conversion done. */
4930 if (!IS_AGGR_TYPE (type))
4931 {
4932 if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
4933 || (TREE_CODE (TREE_TYPE (value)) == METHOD_TYPE
4934 /* Don't do the default conversion on a ->* expression. */
4935 && ! (TREE_CODE (type) == POINTER_TYPE
4936 && bound_pmf_p (value)))
4937 || TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
4938 || TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE)
4939 value = decay_conversion (value);
4940 }
4941 else if (TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE)
4942 /* However, even for class types, we still need to strip away
4943 the reference type, since the call to convert_force below
4944 does not expect the input expression to be of reference
4945 type. */
4946 value = convert_from_reference (value);
4947
4948 otype = TREE_TYPE (value);
4949
4950 /* Optionally warn about potentially worrisome casts. */
4951
4952 if (warn_cast_qual
4953 && TREE_CODE (type) == POINTER_TYPE
4954 && TREE_CODE (otype) == POINTER_TYPE
4955 && !at_least_as_qualified_p (TREE_TYPE (type),
4956 TREE_TYPE (otype)))
4957 warning ("cast from `%T' to `%T' discards qualifiers from pointer target type",
4958 otype, type);
4959
4960 if (TREE_CODE (type) == INTEGER_TYPE
4961 && TYPE_PTR_P (otype)
4962 && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4963 warning ("cast from pointer to integer of different size");
4964
4965 if (TYPE_PTR_P (type)
4966 && TREE_CODE (otype) == INTEGER_TYPE
4967 && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4968 /* Don't warn about converting any constant. */
4969 && !TREE_CONSTANT (value))
4970 warning ("cast to pointer from integer of different size");
4971
4972 if (TREE_CODE (type) == REFERENCE_TYPE)
4973 value = (convert_from_reference
4974 (convert_to_reference (type, value, CONV_C_CAST,
4975 LOOKUP_COMPLAIN, NULL_TREE)));
4976 else
4977 {
4978 tree ovalue;
4979
4980 value = decl_constant_value (value);
4981
4982 ovalue = value;
4983 value = convert_force (type, value, CONV_C_CAST);
4984
4985 /* Ignore any integer overflow caused by the cast. */
4986 if (TREE_CODE (value) == INTEGER_CST)
4987 {
4988 TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4989 TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
4990 }
4991 }
4992
4993 /* Warn about possible alignment problems. Do this here when we will have
4994 instantiated any necessary template types. */
4995 if (STRICT_ALIGNMENT && warn_cast_align
4996 && TREE_CODE (type) == POINTER_TYPE
4997 && TREE_CODE (otype) == POINTER_TYPE
4998 && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4999 && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
5000 && COMPLETE_TYPE_P (TREE_TYPE (otype))
5001 && COMPLETE_TYPE_P (TREE_TYPE (type))
5002 && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
5003 warning ("cast from `%T' to `%T' increases required alignment of target type",
5004 otype, type);
5005
5006 /* Always produce some operator for an explicit cast,
5007 so we can tell (for -pedantic) that the cast is no lvalue. */
5008 if (TREE_CODE (type) != REFERENCE_TYPE && value == expr
5009 && real_lvalue_p (value))
5010 value = non_lvalue (value);
5011
5012 return value;
5013 }
5014
5015 /* Build an assignment expression of lvalue LHS from value RHS.
5016 MODIFYCODE is the code for a binary operator that we use
5017 to combine the old value of LHS with RHS to get the new value.
5018 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
5019
5020 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */
5021
5022 tree
build_modify_expr(tree lhs,enum tree_code modifycode,tree rhs)5023 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
5024 {
5025 tree result;
5026 tree newrhs = rhs;
5027 tree lhstype = TREE_TYPE (lhs);
5028 tree olhstype = lhstype;
5029 tree olhs = NULL_TREE;
5030
5031 /* Avoid duplicate error messages from operands that had errors. */
5032 if (lhs == error_mark_node || rhs == error_mark_node)
5033 return error_mark_node;
5034
5035 /* Handle control structure constructs used as "lvalues". */
5036 switch (TREE_CODE (lhs))
5037 {
5038 /* Handle --foo = 5; as these are valid constructs in C++. */
5039 case PREDECREMENT_EXPR:
5040 case PREINCREMENT_EXPR:
5041 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
5042 lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs),
5043 stabilize_reference (TREE_OPERAND (lhs, 0)),
5044 TREE_OPERAND (lhs, 1));
5045 return build (COMPOUND_EXPR, lhstype,
5046 lhs,
5047 build_modify_expr (TREE_OPERAND (lhs, 0),
5048 modifycode, rhs));
5049
5050 /* Handle (a, b) used as an "lvalue". */
5051 case COMPOUND_EXPR:
5052 newrhs = build_modify_expr (TREE_OPERAND (lhs, 1),
5053 modifycode, rhs);
5054 if (newrhs == error_mark_node)
5055 return error_mark_node;
5056 return build (COMPOUND_EXPR, lhstype,
5057 TREE_OPERAND (lhs, 0), newrhs);
5058
5059 case MODIFY_EXPR:
5060 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
5061 lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs),
5062 stabilize_reference (TREE_OPERAND (lhs, 0)),
5063 TREE_OPERAND (lhs, 1));
5064 newrhs = build_modify_expr (TREE_OPERAND (lhs, 0), modifycode, rhs);
5065 if (newrhs == error_mark_node)
5066 return error_mark_node;
5067 return build (COMPOUND_EXPR, lhstype, lhs, newrhs);
5068
5069 /* Handle (a ? b : c) used as an "lvalue". */
5070 case COND_EXPR:
5071 {
5072 /* Produce (a ? (b = rhs) : (c = rhs))
5073 except that the RHS goes through a save-expr
5074 so the code to compute it is only emitted once. */
5075 tree cond;
5076 tree preeval = NULL_TREE;
5077
5078 rhs = stabilize_expr (rhs, &preeval);
5079
5080 /* Check this here to avoid odd errors when trying to convert
5081 a throw to the type of the COND_EXPR. */
5082 if (!lvalue_or_else (lhs, "assignment"))
5083 return error_mark_node;
5084
5085 cond = build_conditional_expr
5086 (TREE_OPERAND (lhs, 0),
5087 build_modify_expr (cp_convert (TREE_TYPE (lhs),
5088 TREE_OPERAND (lhs, 1)),
5089 modifycode, rhs),
5090 build_modify_expr (cp_convert (TREE_TYPE (lhs),
5091 TREE_OPERAND (lhs, 2)),
5092 modifycode, rhs));
5093
5094 if (cond == error_mark_node)
5095 return cond;
5096 /* Make sure the code to compute the rhs comes out
5097 before the split. */
5098 if (preeval)
5099 cond = build (COMPOUND_EXPR, TREE_TYPE (lhs), preeval, cond);
5100 return cond;
5101 }
5102
5103 default:
5104 break;
5105 }
5106
5107 if (modifycode == INIT_EXPR)
5108 {
5109 if (TREE_CODE (rhs) == CONSTRUCTOR)
5110 {
5111 if (! same_type_p (TREE_TYPE (rhs), lhstype))
5112 /* Call convert to generate an error; see PR 11063. */
5113 rhs = convert (lhstype, rhs);
5114 result = build (INIT_EXPR, lhstype, lhs, rhs);
5115 TREE_SIDE_EFFECTS (result) = 1;
5116 return result;
5117 }
5118 else if (! IS_AGGR_TYPE (lhstype))
5119 /* Do the default thing. */;
5120 else
5121 {
5122 result = build_special_member_call (lhs, complete_ctor_identifier,
5123 build_tree_list (NULL_TREE, rhs),
5124 TYPE_BINFO (lhstype),
5125 LOOKUP_NORMAL);
5126 if (result == NULL_TREE)
5127 return error_mark_node;
5128 return result;
5129 }
5130 }
5131 else
5132 {
5133 if (TREE_CODE (lhstype) == REFERENCE_TYPE)
5134 {
5135 lhs = convert_from_reference (lhs);
5136 olhstype = lhstype = TREE_TYPE (lhs);
5137 }
5138 lhs = require_complete_type (lhs);
5139 if (lhs == error_mark_node)
5140 return error_mark_node;
5141
5142 if (modifycode == NOP_EXPR)
5143 {
5144 /* `operator=' is not an inheritable operator. */
5145 if (! IS_AGGR_TYPE (lhstype))
5146 /* Do the default thing. */;
5147 else
5148 {
5149 result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL,
5150 lhs, rhs, make_node (NOP_EXPR),
5151 /*overloaded_p=*/NULL);
5152 if (result == NULL_TREE)
5153 return error_mark_node;
5154 return result;
5155 }
5156 lhstype = olhstype;
5157 }
5158 else
5159 {
5160 /* A binary op has been requested. Combine the old LHS
5161 value with the RHS producing the value we should actually
5162 store into the LHS. */
5163
5164 my_friendly_assert (!PROMOTES_TO_AGGR_TYPE (lhstype, REFERENCE_TYPE),
5165 978652);
5166 lhs = stabilize_reference (lhs);
5167 newrhs = cp_build_binary_op (modifycode, lhs, rhs);
5168 if (newrhs == error_mark_node)
5169 {
5170 error (" in evaluation of `%Q(%#T, %#T)'", modifycode,
5171 TREE_TYPE (lhs), TREE_TYPE (rhs));
5172 return error_mark_node;
5173 }
5174
5175 /* Now it looks like a plain assignment. */
5176 modifycode = NOP_EXPR;
5177 }
5178 my_friendly_assert (TREE_CODE (lhstype) != REFERENCE_TYPE, 20011220);
5179 my_friendly_assert (TREE_CODE (TREE_TYPE (newrhs)) != REFERENCE_TYPE,
5180 20011220);
5181 }
5182
5183 /* Handle a cast used as an "lvalue".
5184 We have already performed any binary operator using the value as cast.
5185 Now convert the result to the cast type of the lhs,
5186 and then true type of the lhs and store it there;
5187 then convert result back to the cast type to be the value
5188 of the assignment. */
5189
5190 switch (TREE_CODE (lhs))
5191 {
5192 case NOP_EXPR:
5193 case CONVERT_EXPR:
5194 case FLOAT_EXPR:
5195 case FIX_TRUNC_EXPR:
5196 case FIX_FLOOR_EXPR:
5197 case FIX_ROUND_EXPR:
5198 case FIX_CEIL_EXPR:
5199 {
5200 tree inner_lhs = TREE_OPERAND (lhs, 0);
5201 tree result;
5202
5203 if (TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
5204 || TREE_CODE (TREE_TYPE (newrhs)) == FUNCTION_TYPE
5205 || TREE_CODE (TREE_TYPE (newrhs)) == METHOD_TYPE
5206 || TREE_CODE (TREE_TYPE (newrhs)) == OFFSET_TYPE)
5207 newrhs = decay_conversion (newrhs);
5208
5209 /* ISO C++ 5.4/1: The result is an lvalue if T is a reference
5210 type, otherwise the result is an rvalue. */
5211 if (! lvalue_p (lhs))
5212 pedwarn ("ISO C++ forbids cast to non-reference type used as lvalue");
5213
5214 result = build_modify_expr (inner_lhs, NOP_EXPR,
5215 cp_convert (TREE_TYPE (inner_lhs),
5216 cp_convert (lhstype, newrhs)));
5217 if (result == error_mark_node)
5218 return result;
5219 return cp_convert (TREE_TYPE (lhs), result);
5220 }
5221
5222 default:
5223 break;
5224 }
5225
5226 /* Now we have handled acceptable kinds of LHS that are not truly lvalues.
5227 Reject anything strange now. */
5228
5229 if (!lvalue_or_else (lhs, "assignment"))
5230 return error_mark_node;
5231
5232 /* Warn about modifying something that is `const'. Don't warn if
5233 this is initialization. */
5234 if (modifycode != INIT_EXPR
5235 && (TREE_READONLY (lhs) || CP_TYPE_CONST_P (lhstype)
5236 /* Functions are not modifiable, even though they are
5237 lvalues. */
5238 || TREE_CODE (TREE_TYPE (lhs)) == FUNCTION_TYPE
5239 || TREE_CODE (TREE_TYPE (lhs)) == METHOD_TYPE
5240 /* If it's an aggregate and any field is const, then it is
5241 effectively const. */
5242 || (CLASS_TYPE_P (lhstype)
5243 && C_TYPE_FIELDS_READONLY (lhstype))))
5244 readonly_error (lhs, "assignment", 0);
5245
5246 /* If storing into a structure or union member, it has probably been
5247 given type `int'. Compute the type that would go with the actual
5248 amount of storage the member occupies. */
5249
5250 if (TREE_CODE (lhs) == COMPONENT_REF
5251 && (TREE_CODE (lhstype) == INTEGER_TYPE
5252 || TREE_CODE (lhstype) == REAL_TYPE
5253 || TREE_CODE (lhstype) == ENUMERAL_TYPE))
5254 {
5255 lhstype = TREE_TYPE (get_unwidened (lhs, 0));
5256
5257 /* If storing in a field that is in actuality a short or narrower
5258 than one, we must store in the field in its actual type. */
5259
5260 if (lhstype != TREE_TYPE (lhs))
5261 {
5262 /* Avoid warnings converting integral types back into enums for
5263 enum bit fields. */
5264 if (TREE_CODE (lhstype) == INTEGER_TYPE
5265 && TREE_CODE (olhstype) == ENUMERAL_TYPE)
5266 {
5267 if (TREE_SIDE_EFFECTS (lhs))
5268 lhs = stabilize_reference (lhs);
5269 olhs = lhs;
5270 }
5271 lhs = copy_node (lhs);
5272 TREE_TYPE (lhs) = lhstype;
5273 }
5274 }
5275
5276 /* Convert new value to destination type. */
5277
5278 if (TREE_CODE (lhstype) == ARRAY_TYPE)
5279 {
5280 int from_array;
5281
5282 if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype),
5283 TYPE_MAIN_VARIANT (TREE_TYPE (rhs))))
5284 {
5285 error ("incompatible types in assignment of `%T' to `%T'",
5286 TREE_TYPE (rhs), lhstype);
5287 return error_mark_node;
5288 }
5289
5290 /* Allow array assignment in compiler-generated code. */
5291 if (! DECL_ARTIFICIAL (current_function_decl))
5292 pedwarn ("ISO C++ forbids assignment of arrays");
5293
5294 from_array = TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
5295 ? 1 + (modifycode != INIT_EXPR): 0;
5296 return build_vec_init (lhs, NULL_TREE, newrhs, from_array);
5297 }
5298
5299 if (modifycode == INIT_EXPR)
5300 newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL,
5301 "initialization", NULL_TREE, 0);
5302 else
5303 {
5304 /* Avoid warnings on enum bit fields. */
5305 if (TREE_CODE (olhstype) == ENUMERAL_TYPE
5306 && TREE_CODE (lhstype) == INTEGER_TYPE)
5307 {
5308 newrhs = convert_for_assignment (olhstype, newrhs, "assignment",
5309 NULL_TREE, 0);
5310 newrhs = convert_force (lhstype, newrhs, 0);
5311 }
5312 else
5313 newrhs = convert_for_assignment (lhstype, newrhs, "assignment",
5314 NULL_TREE, 0);
5315 if (TREE_CODE (newrhs) == CALL_EXPR
5316 && TYPE_NEEDS_CONSTRUCTING (lhstype))
5317 newrhs = build_cplus_new (lhstype, newrhs);
5318
5319 /* Can't initialize directly from a TARGET_EXPR, since that would
5320 cause the lhs to be constructed twice, and possibly result in
5321 accidental self-initialization. So we force the TARGET_EXPR to be
5322 expanded without a target. */
5323 if (TREE_CODE (newrhs) == TARGET_EXPR)
5324 newrhs = build (COMPOUND_EXPR, TREE_TYPE (newrhs), newrhs,
5325 TREE_OPERAND (newrhs, 0));
5326 }
5327
5328 if (newrhs == error_mark_node)
5329 return error_mark_node;
5330
5331 result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR,
5332 lhstype, lhs, newrhs);
5333
5334 TREE_SIDE_EFFECTS (result) = 1;
5335
5336 /* If we got the LHS in a different type for storing in,
5337 convert the result back to the nominal type of LHS
5338 so that the value we return always has the same type
5339 as the LHS argument. */
5340
5341 if (olhstype == TREE_TYPE (result))
5342 return result;
5343 if (olhs)
5344 {
5345 result = build (COMPOUND_EXPR, olhstype, result, olhs);
5346 TREE_NO_UNUSED_WARNING (result) = 1;
5347 return result;
5348 }
5349 return convert_for_assignment (olhstype, result, "assignment",
5350 NULL_TREE, 0);
5351 }
5352
5353 tree
build_x_modify_expr(tree lhs,enum tree_code modifycode,tree rhs)5354 build_x_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
5355 {
5356 if (processing_template_decl)
5357 return build_min_nt (MODOP_EXPR, lhs,
5358 build_min_nt (modifycode, NULL_TREE, NULL_TREE), rhs);
5359
5360 if (modifycode != NOP_EXPR)
5361 {
5362 tree rval = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, lhs, rhs,
5363 make_node (modifycode),
5364 /*overloaded_p=*/NULL);
5365 if (rval)
5366 return rval;
5367 }
5368 return build_modify_expr (lhs, modifycode, rhs);
5369 }
5370
5371
5372 /* Get difference in deltas for different pointer to member function
5373 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If
5374 the conversion is invalid, the constant is zero. If FORCE is true,
5375 then allow reverse conversions as well.
5376
5377 Note that the naming of FROM and TO is kind of backwards; the return
5378 value is what we add to a TO in order to get a FROM. They are named
5379 this way because we call this function to find out how to convert from
5380 a pointer to member of FROM to a pointer to member of TO. */
5381
5382 static tree
get_delta_difference(tree from,tree to,int force)5383 get_delta_difference (tree from, tree to, int force)
5384 {
5385 tree binfo;
5386 tree virt_binfo;
5387 base_kind kind;
5388
5389 binfo = lookup_base (to, from, ba_check, &kind);
5390 if (kind == bk_inaccessible || kind == bk_ambig)
5391 {
5392 error (" in pointer to member function conversion");
5393 goto error;
5394 }
5395 if (!binfo)
5396 {
5397 if (!force)
5398 {
5399 error_not_base_type (from, to);
5400 error (" in pointer to member conversion");
5401 goto error;
5402 }
5403 binfo = lookup_base (from, to, ba_check, &kind);
5404 if (!binfo)
5405 goto error;
5406 virt_binfo = binfo_from_vbase (binfo);
5407 if (virt_binfo)
5408 {
5409 /* This is a reinterpret cast, we choose to do nothing. */
5410 warning ("pointer to member cast via virtual base `%T'",
5411 BINFO_TYPE (virt_binfo));
5412 goto error;
5413 }
5414 return fold (convert_to_integer (ptrdiff_type_node,
5415 size_diffop (size_zero_node,
5416 BINFO_OFFSET (binfo))));
5417 }
5418
5419 virt_binfo = binfo_from_vbase (binfo);
5420 if (!virt_binfo)
5421 return fold (convert_to_integer (ptrdiff_type_node, BINFO_OFFSET (binfo)));
5422
5423 /* This is a reinterpret cast, we choose to do nothing. */
5424 if (force)
5425 warning ("pointer to member cast via virtual base `%T'",
5426 BINFO_TYPE (virt_binfo));
5427 else
5428 error ("pointer to member conversion via virtual base `%T'",
5429 BINFO_TYPE (virt_binfo));
5430
5431 error:
5432 return fold (convert_to_integer(ptrdiff_type_node, integer_zero_node));
5433 }
5434
5435 /* Return a constructor for the pointer-to-member-function TYPE using
5436 the other components as specified. */
5437
5438 tree
build_ptrmemfunc1(tree type,tree delta,tree pfn)5439 build_ptrmemfunc1 (tree type, tree delta, tree pfn)
5440 {
5441 tree u = NULL_TREE;
5442 tree delta_field;
5443 tree pfn_field;
5444
5445 /* Pull the FIELD_DECLs out of the type. */
5446 pfn_field = TYPE_FIELDS (type);
5447 delta_field = TREE_CHAIN (pfn_field);
5448
5449 /* Make sure DELTA has the type we want. */
5450 delta = convert_and_check (delta_type_node, delta);
5451
5452 /* Finish creating the initializer. */
5453 u = tree_cons (pfn_field, pfn,
5454 build_tree_list (delta_field, delta));
5455 u = build_constructor (type, u);
5456 TREE_CONSTANT (u) = TREE_CONSTANT (pfn) && TREE_CONSTANT (delta);
5457 TREE_STATIC (u) = (TREE_CONSTANT (u)
5458 && (initializer_constant_valid_p (pfn, TREE_TYPE (pfn))
5459 != NULL_TREE)
5460 && (initializer_constant_valid_p (delta, TREE_TYPE (delta))
5461 != NULL_TREE));
5462 return u;
5463 }
5464
5465 /* Build a constructor for a pointer to member function. It can be
5466 used to initialize global variables, local variable, or used
5467 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we
5468 want to be.
5469
5470 If FORCE is nonzero, then force this conversion, even if
5471 we would rather not do it. Usually set when using an explicit
5472 cast.
5473
5474 Return error_mark_node, if something goes wrong. */
5475
5476 tree
build_ptrmemfunc(tree type,tree pfn,int force)5477 build_ptrmemfunc (tree type, tree pfn, int force)
5478 {
5479 tree fn;
5480 tree pfn_type;
5481 tree to_type;
5482
5483 if (error_operand_p (pfn))
5484 return error_mark_node;
5485
5486 pfn_type = TREE_TYPE (pfn);
5487 to_type = build_ptrmemfunc_type (type);
5488
5489 /* Handle multiple conversions of pointer to member functions. */
5490 if (TYPE_PTRMEMFUNC_P (pfn_type))
5491 {
5492 tree delta = NULL_TREE;
5493 tree npfn = NULL_TREE;
5494 tree n;
5495
5496 if (!force
5497 && !can_convert_arg (to_type, TREE_TYPE (pfn), pfn))
5498 error ("invalid conversion to type `%T' from type `%T'",
5499 to_type, pfn_type);
5500
5501 n = get_delta_difference (TYPE_PTRMEMFUNC_OBJECT_TYPE (pfn_type),
5502 TYPE_PTRMEMFUNC_OBJECT_TYPE (to_type),
5503 force);
5504
5505 /* We don't have to do any conversion to convert a
5506 pointer-to-member to its own type. But, we don't want to
5507 just return a PTRMEM_CST if there's an explicit cast; that
5508 cast should make the expression an invalid template argument. */
5509 if (TREE_CODE (pfn) != PTRMEM_CST)
5510 {
5511 if (same_type_p (to_type, pfn_type))
5512 return pfn;
5513 else if (integer_zerop (n))
5514 return build_reinterpret_cast (to_type, pfn);
5515 }
5516
5517 if (TREE_SIDE_EFFECTS (pfn))
5518 pfn = save_expr (pfn);
5519
5520 /* Obtain the function pointer and the current DELTA. */
5521 if (TREE_CODE (pfn) == PTRMEM_CST)
5522 expand_ptrmemfunc_cst (pfn, &delta, &npfn);
5523 else
5524 {
5525 npfn = build_ptrmemfunc_access_expr (pfn, pfn_identifier);
5526 delta = build_ptrmemfunc_access_expr (pfn, delta_identifier);
5527 }
5528
5529 /* Just adjust the DELTA field. */
5530 my_friendly_assert
5531 (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (delta),
5532 ptrdiff_type_node),
5533 20030727);
5534 if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_delta)
5535 n = cp_build_binary_op (LSHIFT_EXPR, n, integer_one_node);
5536 delta = cp_build_binary_op (PLUS_EXPR, delta, n);
5537 return build_ptrmemfunc1 (to_type, delta, npfn);
5538 }
5539
5540 /* Handle null pointer to member function conversions. */
5541 if (integer_zerop (pfn))
5542 {
5543 pfn = build_c_cast (type, integer_zero_node);
5544 return build_ptrmemfunc1 (to_type,
5545 integer_zero_node,
5546 pfn);
5547 }
5548
5549 if (type_unknown_p (pfn))
5550 return instantiate_type (type, pfn, tf_error | tf_warning);
5551
5552 fn = TREE_OPERAND (pfn, 0);
5553 my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0);
5554 return make_ptrmem_cst (to_type, fn);
5555 }
5556
5557 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
5558 given by CST.
5559
5560 ??? There is no consistency as to the types returned for the above
5561 values. Some code acts as if its a sizetype and some as if its
5562 integer_type_node. */
5563
5564 void
expand_ptrmemfunc_cst(tree cst,tree * delta,tree * pfn)5565 expand_ptrmemfunc_cst (tree cst, tree *delta, tree *pfn)
5566 {
5567 tree type = TREE_TYPE (cst);
5568 tree fn = PTRMEM_CST_MEMBER (cst);
5569 tree ptr_class, fn_class;
5570
5571 my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0);
5572
5573 /* The class that the function belongs to. */
5574 fn_class = DECL_CONTEXT (fn);
5575
5576 /* The class that we're creating a pointer to member of. */
5577 ptr_class = TYPE_PTRMEMFUNC_OBJECT_TYPE (type);
5578
5579 /* First, calculate the adjustment to the function's class. */
5580 *delta = get_delta_difference (fn_class, ptr_class, /*force=*/0);
5581
5582 if (!DECL_VIRTUAL_P (fn))
5583 *pfn = convert (TYPE_PTRMEMFUNC_FN_TYPE (type), build_addr_func (fn));
5584 else
5585 {
5586 /* If we're dealing with a virtual function, we have to adjust 'this'
5587 again, to point to the base which provides the vtable entry for
5588 fn; the call will do the opposite adjustment. */
5589 tree orig_class = DECL_CONTEXT (fn);
5590 tree binfo = binfo_or_else (orig_class, fn_class);
5591 *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta),
5592 *delta, BINFO_OFFSET (binfo)));
5593
5594 /* We set PFN to the vtable offset at which the function can be
5595 found, plus one (unless ptrmemfunc_vbit_in_delta, in which
5596 case delta is shifted left, and then incremented). */
5597 *pfn = DECL_VINDEX (fn);
5598 *pfn = fold (build (MULT_EXPR, integer_type_node, *pfn,
5599 TYPE_SIZE_UNIT (vtable_entry_type)));
5600
5601 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION)
5602 {
5603 case ptrmemfunc_vbit_in_pfn:
5604 *pfn = fold (build (PLUS_EXPR, integer_type_node, *pfn,
5605 integer_one_node));
5606 break;
5607
5608 case ptrmemfunc_vbit_in_delta:
5609 *delta = fold (build (LSHIFT_EXPR, TREE_TYPE (*delta),
5610 *delta, integer_one_node));
5611 *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta),
5612 *delta, integer_one_node));
5613 break;
5614
5615 default:
5616 abort ();
5617 }
5618
5619 *pfn = fold (build1 (NOP_EXPR, TYPE_PTRMEMFUNC_FN_TYPE (type),
5620 *pfn));
5621 }
5622 }
5623
5624 /* Return an expression for PFN from the pointer-to-member function
5625 given by T. */
5626
5627 tree
pfn_from_ptrmemfunc(tree t)5628 pfn_from_ptrmemfunc (tree t)
5629 {
5630 if (TREE_CODE (t) == PTRMEM_CST)
5631 {
5632 tree delta;
5633 tree pfn;
5634
5635 expand_ptrmemfunc_cst (t, &delta, &pfn);
5636 if (pfn)
5637 return pfn;
5638 }
5639
5640 return build_ptrmemfunc_access_expr (t, pfn_identifier);
5641 }
5642
5643 /* Expression EXPR is about to be implicitly converted to TYPE. Warn
5644 if this is a potentially dangerous thing to do. Returns a possibly
5645 marked EXPR. */
5646
5647 tree
dubious_conversion_warnings(tree type,tree expr,const char * errtype,tree fndecl,int parmnum)5648 dubious_conversion_warnings (tree type, tree expr,
5649 const char *errtype, tree fndecl, int parmnum)
5650 {
5651 type = non_reference (type);
5652
5653 /* Issue warnings about peculiar, but valid, uses of NULL. */
5654 if (ARITHMETIC_TYPE_P (type) && expr == null_node)
5655 {
5656 if (fndecl)
5657 warning ("passing NULL used for non-pointer %s %P of `%D'",
5658 errtype, parmnum, fndecl);
5659 else
5660 warning ("%s to non-pointer type `%T' from NULL", errtype, type);
5661 }
5662
5663 /* Warn about assigning a floating-point type to an integer type. */
5664 if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
5665 && TREE_CODE (type) == INTEGER_TYPE)
5666 {
5667 if (fndecl)
5668 warning ("passing `%T' for %s %P of `%D'",
5669 TREE_TYPE (expr), errtype, parmnum, fndecl);
5670 else
5671 warning ("%s to `%T' from `%T'", errtype, type, TREE_TYPE (expr));
5672 }
5673 /* And warn about assigning a negative value to an unsigned
5674 variable. */
5675 else if (TREE_UNSIGNED (type) && TREE_CODE (type) != BOOLEAN_TYPE)
5676 {
5677 if (TREE_CODE (expr) == INTEGER_CST
5678 && TREE_NEGATED_INT (expr))
5679 {
5680 if (fndecl)
5681 warning ("passing negative value `%E' for %s %P of `%D'",
5682 expr, errtype, parmnum, fndecl);
5683 else
5684 warning ("%s of negative value `%E' to `%T'",
5685 errtype, expr, type);
5686 }
5687
5688 overflow_warning (expr);
5689
5690 if (TREE_CONSTANT (expr))
5691 expr = fold (expr);
5692 }
5693 return expr;
5694 }
5695
5696 /* Convert value RHS to type TYPE as preparation for an assignment to
5697 an lvalue of type TYPE. ERRTYPE is a string to use in error
5698 messages: "assignment", "return", etc. If FNDECL is non-NULL, we
5699 are doing the conversion in order to pass the PARMNUMth argument of
5700 FNDECL. */
5701
5702 static tree
convert_for_assignment(tree type,tree rhs,const char * errtype,tree fndecl,int parmnum)5703 convert_for_assignment (tree type, tree rhs,
5704 const char *errtype, tree fndecl, int parmnum)
5705 {
5706 tree rhstype;
5707 enum tree_code coder;
5708
5709 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
5710 if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
5711 rhs = TREE_OPERAND (rhs, 0);
5712
5713 rhstype = TREE_TYPE (rhs);
5714 coder = TREE_CODE (rhstype);
5715
5716 if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE
5717 && ((*targetm.vector_opaque_p) (type)
5718 || (*targetm.vector_opaque_p) (rhstype)))
5719 return convert (type, rhs);
5720
5721 if (rhs == error_mark_node || rhstype == error_mark_node)
5722 return error_mark_node;
5723 if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)
5724 return error_mark_node;
5725
5726 /* The RHS of an assignment cannot have void type. */
5727 if (coder == VOID_TYPE)
5728 {
5729 error ("void value not ignored as it ought to be");
5730 return error_mark_node;
5731 }
5732
5733 /* Simplify the RHS if possible. */
5734 if (TREE_CODE (rhs) == CONST_DECL)
5735 rhs = DECL_INITIAL (rhs);
5736
5737 /* We do not use decl_constant_value here because of this case:
5738
5739 const char* const s = "s";
5740
5741 The conversion rules for a string literal are more lax than for a
5742 variable; in particular, a string literal can be converted to a
5743 "char *" but the variable "s" cannot be converted in the same
5744 way. If the conversion is allowed, the optimization should be
5745 performed while creating the converted expression. */
5746
5747 /* [expr.ass]
5748
5749 The expression is implicitly converted (clause _conv_) to the
5750 cv-unqualified type of the left operand.
5751
5752 We allow bad conversions here because by the time we get to this point
5753 we are committed to doing the conversion. If we end up doing a bad
5754 conversion, convert_like will complain. */
5755 if (!can_convert_arg_bad (type, rhstype, rhs))
5756 {
5757 /* When -Wno-pmf-conversions is use, we just silently allow
5758 conversions from pointers-to-members to plain pointers. If
5759 the conversion doesn't work, cp_convert will complain. */
5760 if (!warn_pmf2ptr
5761 && TYPE_PTR_P (type)
5762 && TYPE_PTRMEMFUNC_P (rhstype))
5763 rhs = cp_convert (strip_top_quals (type), rhs);
5764 else
5765 {
5766 /* If the right-hand side has unknown type, then it is an
5767 overloaded function. Call instantiate_type to get error
5768 messages. */
5769 if (rhstype == unknown_type_node)
5770 instantiate_type (type, rhs, tf_error | tf_warning);
5771 else if (fndecl)
5772 error ("cannot convert `%T' to `%T' for argument `%P' to `%D'",
5773 rhstype, type, parmnum, fndecl);
5774 else
5775 error ("cannot convert `%T' to `%T' in %s", rhstype, type,
5776 errtype);
5777 return error_mark_node;
5778 }
5779 }
5780 return perform_implicit_conversion (strip_top_quals (type), rhs);
5781 }
5782
5783 /* Convert RHS to be of type TYPE.
5784 If EXP is nonzero, it is the target of the initialization.
5785 ERRTYPE is a string to use in error messages.
5786
5787 Two major differences between the behavior of
5788 `convert_for_assignment' and `convert_for_initialization'
5789 are that references are bashed in the former, while
5790 copied in the latter, and aggregates are assigned in
5791 the former (operator=) while initialized in the
5792 latter (X(X&)).
5793
5794 If using constructor make sure no conversion operator exists, if one does
5795 exist, an ambiguity exists.
5796
5797 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */
5798
5799 tree
convert_for_initialization(tree exp,tree type,tree rhs,int flags,const char * errtype,tree fndecl,int parmnum)5800 convert_for_initialization (tree exp, tree type, tree rhs, int flags,
5801 const char *errtype, tree fndecl, int parmnum)
5802 {
5803 enum tree_code codel = TREE_CODE (type);
5804 tree rhstype;
5805 enum tree_code coder;
5806
5807 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5808 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */
5809 if (TREE_CODE (rhs) == NOP_EXPR
5810 && TREE_TYPE (rhs) == TREE_TYPE (TREE_OPERAND (rhs, 0))
5811 && codel != REFERENCE_TYPE)
5812 rhs = TREE_OPERAND (rhs, 0);
5813
5814 if (rhs == error_mark_node
5815 || (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node))
5816 return error_mark_node;
5817
5818 if (TREE_CODE (TREE_TYPE (rhs)) == REFERENCE_TYPE)
5819 rhs = convert_from_reference (rhs);
5820
5821 if ((TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
5822 && TREE_CODE (type) != ARRAY_TYPE
5823 && (TREE_CODE (type) != REFERENCE_TYPE
5824 || TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE))
5825 || (TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE
5826 && (TREE_CODE (type) != REFERENCE_TYPE
5827 || TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE))
5828 || TREE_CODE (TREE_TYPE (rhs)) == METHOD_TYPE)
5829 rhs = decay_conversion (rhs);
5830
5831 rhstype = TREE_TYPE (rhs);
5832 coder = TREE_CODE (rhstype);
5833
5834 if (coder == ERROR_MARK)
5835 return error_mark_node;
5836
5837 /* We accept references to incomplete types, so we can
5838 return here before checking if RHS is of complete type. */
5839
5840 if (codel == REFERENCE_TYPE)
5841 {
5842 /* This should eventually happen in convert_arguments. */
5843 int savew = 0, savee = 0;
5844
5845 if (fndecl)
5846 savew = warningcount, savee = errorcount;
5847 rhs = initialize_reference (type, rhs, /*decl=*/NULL_TREE,
5848 /*cleanup=*/NULL);
5849 if (fndecl)
5850 {
5851 if (warningcount > savew)
5852 cp_warning_at ("in passing argument %P of `%+D'", parmnum, fndecl);
5853 else if (errorcount > savee)
5854 cp_error_at ("in passing argument %P of `%+D'", parmnum, fndecl);
5855 }
5856 return rhs;
5857 }
5858
5859 if (exp != 0)
5860 exp = require_complete_type (exp);
5861 if (exp == error_mark_node)
5862 return error_mark_node;
5863
5864 rhstype = non_reference (rhstype);
5865
5866 type = complete_type (type);
5867
5868 if (IS_AGGR_TYPE (type))
5869 return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags);
5870
5871 return convert_for_assignment (type, rhs, errtype, fndecl, parmnum);
5872 }
5873
5874 /* Expand an ASM statement with operands, handling output operands
5875 that are not variables or INDIRECT_REFS by transforming such
5876 cases into cases that expand_asm_operands can handle.
5877
5878 Arguments are same as for expand_asm_operands.
5879
5880 We don't do default conversions on all inputs, because it can screw
5881 up operands that are expected to be in memory. */
5882
5883 void
c_expand_asm_operands(tree string,tree outputs,tree inputs,tree clobbers,int vol,location_t locus)5884 c_expand_asm_operands (tree string, tree outputs, tree inputs, tree clobbers,
5885 int vol, location_t locus)
5886 {
5887 int noutputs = list_length (outputs);
5888 int i;
5889 /* o[I] is the place that output number I should be written. */
5890 tree *o = alloca (noutputs * sizeof (tree));
5891 tree tail;
5892
5893 /* Record the contents of OUTPUTS before it is modified. */
5894 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
5895 o[i] = TREE_VALUE (tail);
5896
5897 /* Generate the ASM_OPERANDS insn;
5898 store into the TREE_VALUEs of OUTPUTS some trees for
5899 where the values were actually stored. */
5900 expand_asm_operands (string, outputs, inputs, clobbers, vol, locus);
5901
5902 /* Copy all the intermediate outputs into the specified outputs. */
5903 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
5904 {
5905 if (o[i] != TREE_VALUE (tail))
5906 {
5907 expand_expr (build_modify_expr (o[i], NOP_EXPR, TREE_VALUE (tail)),
5908 const0_rtx, VOIDmode, EXPAND_NORMAL);
5909 free_temp_slots ();
5910
5911 /* Restore the original value so that it's correct the next
5912 time we expand this function. */
5913 TREE_VALUE (tail) = o[i];
5914 }
5915 /* Detect modification of read-only values.
5916 (Otherwise done by build_modify_expr.) */
5917 else
5918 {
5919 tree type = TREE_TYPE (o[i]);
5920 if (type != error_mark_node
5921 && (CP_TYPE_CONST_P (type)
5922 || (CLASS_TYPE_P (type) && C_TYPE_FIELDS_READONLY (type))))
5923 readonly_error (o[i], "modification by `asm'", 1);
5924 }
5925 }
5926
5927 /* Those MODIFY_EXPRs could do autoincrements. */
5928 emit_queue ();
5929 }
5930
5931 /* If RETVAL is the address of, or a reference to, a local variable or
5932 temporary give an appropriate warning. */
5933
5934 static void
maybe_warn_about_returning_address_of_local(tree retval)5935 maybe_warn_about_returning_address_of_local (tree retval)
5936 {
5937 tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl));
5938 tree whats_returned = retval;
5939
5940 for (;;)
5941 {
5942 if (TREE_CODE (whats_returned) == COMPOUND_EXPR)
5943 whats_returned = TREE_OPERAND (whats_returned, 1);
5944 else if (TREE_CODE (whats_returned) == CONVERT_EXPR
5945 || TREE_CODE (whats_returned) == NON_LVALUE_EXPR
5946 || TREE_CODE (whats_returned) == NOP_EXPR)
5947 whats_returned = TREE_OPERAND (whats_returned, 0);
5948 else
5949 break;
5950 }
5951
5952 if (TREE_CODE (whats_returned) != ADDR_EXPR)
5953 return;
5954 whats_returned = TREE_OPERAND (whats_returned, 0);
5955
5956 if (TREE_CODE (valtype) == REFERENCE_TYPE)
5957 {
5958 if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR
5959 || TREE_CODE (whats_returned) == TARGET_EXPR)
5960 {
5961 warning ("returning reference to temporary");
5962 return;
5963 }
5964 if (TREE_CODE (whats_returned) == VAR_DECL
5965 && DECL_NAME (whats_returned)
5966 && TEMP_NAME_P (DECL_NAME (whats_returned)))
5967 {
5968 warning ("reference to non-lvalue returned");
5969 return;
5970 }
5971 }
5972
5973 if (TREE_CODE (whats_returned) == VAR_DECL
5974 && DECL_NAME (whats_returned)
5975 && DECL_FUNCTION_SCOPE_P (whats_returned)
5976 && !(TREE_STATIC (whats_returned)
5977 || TREE_PUBLIC (whats_returned)))
5978 {
5979 if (TREE_CODE (valtype) == REFERENCE_TYPE)
5980 cp_warning_at ("reference to local variable `%D' returned",
5981 whats_returned);
5982 else
5983 cp_warning_at ("address of local variable `%D' returned",
5984 whats_returned);
5985 return;
5986 }
5987 }
5988
5989 /* Check that returning RETVAL from the current function is valid.
5990 Return an expression explicitly showing all conversions required to
5991 change RETVAL into the function return type, and to assign it to
5992 the DECL_RESULT for the function. */
5993
5994 tree
check_return_expr(tree retval)5995 check_return_expr (tree retval)
5996 {
5997 tree result;
5998 /* The type actually returned by the function, after any
5999 promotions. */
6000 tree valtype;
6001 int fn_returns_value_p;
6002
6003 /* A `volatile' function is one that isn't supposed to return, ever.
6004 (This is a G++ extension, used to get better code for functions
6005 that call the `volatile' function.) */
6006 if (TREE_THIS_VOLATILE (current_function_decl))
6007 warning ("function declared `noreturn' has a `return' statement");
6008
6009 /* Check for various simple errors. */
6010 if (DECL_DESTRUCTOR_P (current_function_decl))
6011 {
6012 if (retval)
6013 error ("returning a value from a destructor");
6014 return NULL_TREE;
6015 }
6016 else if (DECL_CONSTRUCTOR_P (current_function_decl))
6017 {
6018 if (in_function_try_handler)
6019 /* If a return statement appears in a handler of the
6020 function-try-block of a constructor, the program is ill-formed. */
6021 error ("cannot return from a handler of a function-try-block of a constructor");
6022 else if (retval)
6023 /* You can't return a value from a constructor. */
6024 error ("returning a value from a constructor");
6025 return NULL_TREE;
6026 }
6027
6028 if (processing_template_decl)
6029 {
6030 current_function_returns_value = 1;
6031 return retval;
6032 }
6033
6034 /* When no explicit return-value is given in a function with a named
6035 return value, the named return value is used. */
6036 result = DECL_RESULT (current_function_decl);
6037 valtype = TREE_TYPE (result);
6038 my_friendly_assert (valtype != NULL_TREE, 19990924);
6039 fn_returns_value_p = !VOID_TYPE_P (valtype);
6040 if (!retval && DECL_NAME (result) && fn_returns_value_p)
6041 retval = result;
6042
6043 /* Check for a return statement with no return value in a function
6044 that's supposed to return a value. */
6045 if (!retval && fn_returns_value_p)
6046 {
6047 pedwarn ("return-statement with no value, in function returning '%T'",
6048 valtype);
6049 /* Clear this, so finish_function won't say that we reach the
6050 end of a non-void function (which we don't, we gave a
6051 return!). */
6052 current_function_returns_null = 0;
6053 }
6054 /* Check for a return statement with a value in a function that
6055 isn't supposed to return a value. */
6056 else if (retval && !fn_returns_value_p)
6057 {
6058 if (VOID_TYPE_P (TREE_TYPE (retval)))
6059 /* You can return a `void' value from a function of `void'
6060 type. In that case, we have to evaluate the expression for
6061 its side-effects. */
6062 finish_expr_stmt (retval);
6063 else
6064 pedwarn ("return-statement with a value, in function "
6065 "returning 'void'");
6066
6067 current_function_returns_null = 1;
6068
6069 /* There's really no value to return, after all. */
6070 return NULL_TREE;
6071 }
6072 else if (!retval)
6073 /* Remember that this function can sometimes return without a
6074 value. */
6075 current_function_returns_null = 1;
6076 else
6077 /* Remember that this function did return a value. */
6078 current_function_returns_value = 1;
6079
6080 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */
6081 if ((DECL_OVERLOADED_OPERATOR_P (current_function_decl) == NEW_EXPR
6082 || DECL_OVERLOADED_OPERATOR_P (current_function_decl) == VEC_NEW_EXPR)
6083 && !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl))
6084 && ! flag_check_new
6085 && null_ptr_cst_p (retval))
6086 warning ("`operator new' must not return NULL unless it is declared `throw()' (or -fcheck-new is in effect)");
6087
6088 /* Effective C++ rule 15. See also start_function. */
6089 if (warn_ecpp
6090 && DECL_NAME (current_function_decl) == ansi_assopname(NOP_EXPR)
6091 && retval != current_class_ref)
6092 warning ("`operator=' should return a reference to `*this'");
6093
6094 /* The fabled Named Return Value optimization, as per [class.copy]/15:
6095
6096 [...] For a function with a class return type, if the expression
6097 in the return statement is the name of a local object, and the cv-
6098 unqualified type of the local object is the same as the function
6099 return type, an implementation is permitted to omit creating the tem-
6100 porary object to hold the function return value [...]
6101
6102 So, if this is a value-returning function that always returns the same
6103 local variable, remember it.
6104
6105 It might be nice to be more flexible, and choose the first suitable
6106 variable even if the function sometimes returns something else, but
6107 then we run the risk of clobbering the variable we chose if the other
6108 returned expression uses the chosen variable somehow. And people expect
6109 this restriction, anyway. (jason 2000-11-19)
6110
6111 See finish_function, cxx_expand_function_start, and
6112 cp_copy_res_decl_for_inlining for other pieces of this
6113 optimization. */
6114
6115 if (fn_returns_value_p && flag_elide_constructors)
6116 {
6117 if (retval != NULL_TREE
6118 && (current_function_return_value == NULL_TREE
6119 || current_function_return_value == retval)
6120 && TREE_CODE (retval) == VAR_DECL
6121 && DECL_CONTEXT (retval) == current_function_decl
6122 && ! TREE_STATIC (retval)
6123 && (DECL_ALIGN (retval)
6124 >= DECL_ALIGN (DECL_RESULT (current_function_decl)))
6125 && same_type_p ((TYPE_MAIN_VARIANT
6126 (TREE_TYPE (retval))),
6127 (TYPE_MAIN_VARIANT
6128 (TREE_TYPE (TREE_TYPE (current_function_decl))))))
6129 current_function_return_value = retval;
6130 else
6131 current_function_return_value = error_mark_node;
6132 }
6133
6134 /* We don't need to do any conversions when there's nothing being
6135 returned. */
6136 if (!retval || retval == error_mark_node)
6137 return retval;
6138
6139 /* Do any required conversions. */
6140 if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl))
6141 /* No conversions are required. */
6142 ;
6143 else
6144 {
6145 /* The type the function is declared to return. */
6146 tree functype = TREE_TYPE (TREE_TYPE (current_function_decl));
6147
6148 /* First convert the value to the function's return type, then
6149 to the type of return value's location to handle the
6150 case that functype is smaller than the valtype. */
6151 retval = convert_for_initialization
6152 (NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING,
6153 "return", NULL_TREE, 0);
6154 retval = convert (valtype, retval);
6155
6156 /* If the conversion failed, treat this just like `return;'. */
6157 if (retval == error_mark_node)
6158 return retval;
6159 /* We can't initialize a register from a AGGR_INIT_EXPR. */
6160 else if (! current_function_returns_struct
6161 && TREE_CODE (retval) == TARGET_EXPR
6162 && TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR)
6163 retval = build (COMPOUND_EXPR, TREE_TYPE (retval), retval,
6164 TREE_OPERAND (retval, 0));
6165 else
6166 maybe_warn_about_returning_address_of_local (retval);
6167 }
6168
6169 /* Actually copy the value returned into the appropriate location. */
6170 if (retval && retval != result)
6171 retval = build (INIT_EXPR, TREE_TYPE (result), result, retval);
6172
6173 return retval;
6174 }
6175
6176
6177 /* Returns nonzero if the pointer-type FROM can be converted to the
6178 pointer-type TO via a qualification conversion. If CONSTP is -1,
6179 then we return nonzero if the pointers are similar, and the
6180 cv-qualification signature of FROM is a proper subset of that of TO.
6181
6182 If CONSTP is positive, then all outer pointers have been
6183 const-qualified. */
6184
6185 static int
comp_ptr_ttypes_real(tree to,tree from,int constp)6186 comp_ptr_ttypes_real (tree to, tree from, int constp)
6187 {
6188 bool to_more_cv_qualified = false;
6189
6190 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6191 {
6192 if (TREE_CODE (to) != TREE_CODE (from))
6193 return 0;
6194
6195 if (TREE_CODE (from) == OFFSET_TYPE
6196 && !same_type_p (TYPE_OFFSET_BASETYPE (from),
6197 TYPE_OFFSET_BASETYPE (to)))
6198 return 0;
6199
6200 /* Const and volatile mean something different for function types,
6201 so the usual checks are not appropriate. */
6202 if (TREE_CODE (to) != FUNCTION_TYPE && TREE_CODE (to) != METHOD_TYPE)
6203 {
6204 if (!at_least_as_qualified_p (to, from))
6205 return 0;
6206
6207 if (!at_least_as_qualified_p (from, to))
6208 {
6209 if (constp == 0)
6210 return 0;
6211 to_more_cv_qualified = true;
6212 }
6213
6214 if (constp > 0)
6215 constp &= TYPE_READONLY (to);
6216 }
6217
6218 if (TREE_CODE (to) != POINTER_TYPE && !TYPE_PTRMEM_P (to))
6219 return ((constp >= 0 || to_more_cv_qualified)
6220 && same_type_ignoring_top_level_qualifiers_p (to, from));
6221 }
6222 }
6223
6224 /* When comparing, say, char ** to char const **, this function takes
6225 the 'char *' and 'char const *'. Do not pass non-pointer/reference
6226 types to this function. */
6227
6228 int
comp_ptr_ttypes(tree to,tree from)6229 comp_ptr_ttypes (tree to, tree from)
6230 {
6231 return comp_ptr_ttypes_real (to, from, 1);
6232 }
6233
6234 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6235 type or inheritance-related types, regardless of cv-quals. */
6236
6237 int
ptr_reasonably_similar(tree to,tree from)6238 ptr_reasonably_similar (tree to, tree from)
6239 {
6240 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6241 {
6242 /* Any target type is similar enough to void. */
6243 if (TREE_CODE (to) == VOID_TYPE
6244 || TREE_CODE (from) == VOID_TYPE)
6245 return 1;
6246
6247 if (TREE_CODE (to) != TREE_CODE (from))
6248 return 0;
6249
6250 if (TREE_CODE (from) == OFFSET_TYPE
6251 && comptypes (TYPE_OFFSET_BASETYPE (to),
6252 TYPE_OFFSET_BASETYPE (from),
6253 COMPARE_BASE | COMPARE_DERIVED))
6254 continue;
6255
6256 if (TREE_CODE (to) == INTEGER_TYPE
6257 && TYPE_PRECISION (to) == TYPE_PRECISION (from))
6258 return 1;
6259
6260 if (TREE_CODE (to) == FUNCTION_TYPE)
6261 return 1;
6262
6263 if (TREE_CODE (to) != POINTER_TYPE)
6264 return comptypes
6265 (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from),
6266 COMPARE_BASE | COMPARE_DERIVED);
6267 }
6268 }
6269
6270 /* Like comp_ptr_ttypes, for const_cast. */
6271
6272 static int
comp_ptr_ttypes_const(tree to,tree from)6273 comp_ptr_ttypes_const (tree to, tree from)
6274 {
6275 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6276 {
6277 if (TREE_CODE (to) != TREE_CODE (from))
6278 return 0;
6279
6280 if (TREE_CODE (from) == OFFSET_TYPE
6281 && same_type_p (TYPE_OFFSET_BASETYPE (from),
6282 TYPE_OFFSET_BASETYPE (to)))
6283 continue;
6284
6285 if (TREE_CODE (to) != POINTER_TYPE)
6286 return same_type_ignoring_top_level_qualifiers_p (to, from);
6287 }
6288 }
6289
6290 /* Returns the type qualifiers for this type, including the qualifiers on the
6291 elements for an array type. */
6292
6293 int
cp_type_quals(tree type)6294 cp_type_quals (tree type)
6295 {
6296 type = strip_array_types (type);
6297 if (type == error_mark_node)
6298 return TYPE_UNQUALIFIED;
6299 return TYPE_QUALS (type);
6300 }
6301
6302 /* Returns nonzero if the TYPE contains a mutable member. */
6303
6304 bool
cp_has_mutable_p(tree type)6305 cp_has_mutable_p (tree type)
6306 {
6307 type = strip_array_types (type);
6308
6309 return CLASS_TYPE_P (type) && CLASSTYPE_HAS_MUTABLE (type);
6310 }
6311
6312 /* Subroutine of casts_away_constness. Make T1 and T2 point at
6313 exemplar types such that casting T1 to T2 is casting away castness
6314 if and only if there is no implicit conversion from T1 to T2. */
6315
6316 static void
casts_away_constness_r(tree * t1,tree * t2)6317 casts_away_constness_r (tree *t1, tree *t2)
6318 {
6319 int quals1;
6320 int quals2;
6321
6322 /* [expr.const.cast]
6323
6324 For multi-level pointer to members and multi-level mixed pointers
6325 and pointers to members (conv.qual), the "member" aspect of a
6326 pointer to member level is ignored when determining if a const
6327 cv-qualifier has been cast away. */
6328 if (TYPE_PTRMEM_P (*t1))
6329 *t1 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t1));
6330 if (TYPE_PTRMEM_P (*t2))
6331 *t2 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t2));
6332
6333 /* [expr.const.cast]
6334
6335 For two pointer types:
6336
6337 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type
6338 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type
6339 K is min(N,M)
6340
6341 casting from X1 to X2 casts away constness if, for a non-pointer
6342 type T there does not exist an implicit conversion (clause
6343 _conv_) from:
6344
6345 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6346
6347 to
6348
6349 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */
6350
6351 if (TREE_CODE (*t1) != POINTER_TYPE
6352 || TREE_CODE (*t2) != POINTER_TYPE)
6353 {
6354 *t1 = cp_build_qualified_type (void_type_node,
6355 cp_type_quals (*t1));
6356 *t2 = cp_build_qualified_type (void_type_node,
6357 cp_type_quals (*t2));
6358 return;
6359 }
6360
6361 quals1 = cp_type_quals (*t1);
6362 quals2 = cp_type_quals (*t2);
6363 *t1 = TREE_TYPE (*t1);
6364 *t2 = TREE_TYPE (*t2);
6365 casts_away_constness_r (t1, t2);
6366 *t1 = build_pointer_type (*t1);
6367 *t2 = build_pointer_type (*t2);
6368 *t1 = cp_build_qualified_type (*t1, quals1);
6369 *t2 = cp_build_qualified_type (*t2, quals2);
6370 }
6371
6372 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6373 constness. */
6374
6375 static bool
casts_away_constness(tree t1,tree t2)6376 casts_away_constness (tree t1, tree t2)
6377 {
6378 if (TREE_CODE (t2) == REFERENCE_TYPE)
6379 {
6380 /* [expr.const.cast]
6381
6382 Casting from an lvalue of type T1 to an lvalue of type T2
6383 using a reference cast casts away constness if a cast from an
6384 rvalue of type "pointer to T1" to the type "pointer to T2"
6385 casts away constness. */
6386 t1 = (TREE_CODE (t1) == REFERENCE_TYPE ? TREE_TYPE (t1) : t1);
6387 return casts_away_constness (build_pointer_type (t1),
6388 build_pointer_type (TREE_TYPE (t2)));
6389 }
6390
6391 if (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2))
6392 /* [expr.const.cast]
6393
6394 Casting from an rvalue of type "pointer to data member of X
6395 of type T1" to the type "pointer to data member of Y of type
6396 T2" casts away constness if a cast from an rvalue of type
6397 "pointer to T1" to the type "pointer to T2" casts away
6398 constness. */
6399 return casts_away_constness
6400 (build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t1)),
6401 build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t2)));
6402
6403 /* Casting away constness is only something that makes sense for
6404 pointer or reference types. */
6405 if (TREE_CODE (t1) != POINTER_TYPE
6406 || TREE_CODE (t2) != POINTER_TYPE)
6407 return false;
6408
6409 /* Top-level qualifiers don't matter. */
6410 t1 = TYPE_MAIN_VARIANT (t1);
6411 t2 = TYPE_MAIN_VARIANT (t2);
6412 casts_away_constness_r (&t1, &t2);
6413 if (!can_convert (t2, t1))
6414 return true;
6415
6416 return false;
6417 }
6418
6419 /* If T is a REFERENCE_TYPE return the type to which T refers.
6420 Otherwise, return T itself. */
6421
6422 tree
non_reference(tree t)6423 non_reference (tree t)
6424 {
6425 if (TREE_CODE (t) == REFERENCE_TYPE)
6426 t = TREE_TYPE (t);
6427 return t;
6428 }
6429