Line data Source code
1 : /* Language-level data type conversion for GNU C++.
2 : Copyright (C) 1987-2026 Free Software Foundation, Inc.
3 : Hacked by Michael Tiemann (tiemann@cygnus.com)
4 :
5 : This file is part of GCC.
6 :
7 : GCC is free software; you can redistribute it and/or modify
8 : it under the terms of the GNU General Public License as published by
9 : the Free Software Foundation; either version 3, or (at your option)
10 : any later version.
11 :
12 : GCC is distributed in the hope that it will be useful,
13 : but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : GNU General Public License for more details.
16 :
17 : You should have received a copy of the GNU General Public License
18 : along with GCC; see the file COPYING3. If not see
19 : <http://www.gnu.org/licenses/>. */
20 :
21 :
22 : /* This file contains the functions for converting C++ expressions
23 : to different data types. The only entry point is `convert'.
24 : Every language front end must have a `convert' function
25 : but what kind of conversions it does will depend on the language. */
26 :
27 : #include "config.h"
28 : #include "system.h"
29 : #include "coretypes.h"
30 : #include "target.h"
31 : #include "cp-tree.h"
32 : #include "stor-layout.h"
33 : #include "flags.h"
34 : #include "intl.h"
35 : #include "convert.h"
36 : #include "stringpool.h"
37 : #include "attribs.h"
38 : #include "escaped_string.h"
39 : #include "gcc-urlifier.h"
40 :
41 : static tree convert_to_pointer_force (tree, tree, tsubst_flags_t);
42 : static tree build_type_conversion (tree, tree);
43 : static tree build_up_reference (tree, tree, int, tree, tsubst_flags_t);
44 : static void diagnose_ref_binding (location_t, tree, tree, tree);
45 :
46 : /* Change of width--truncation and extension of integers or reals--
47 : is represented with NOP_EXPR. Proper functioning of many things
48 : assumes that no other conversions can be NOP_EXPRs.
49 :
50 : Conversion between integer and pointer is represented with CONVERT_EXPR.
51 : Converting integer to real uses FLOAT_EXPR
52 : and real to integer uses FIX_TRUNC_EXPR.
53 :
54 : Here is a list of all the functions that assume that widening and
55 : narrowing is always done with a NOP_EXPR:
56 : In convert.cc, convert_to_integer[_maybe_fold].
57 : In c-typeck.cc, build_binary_op_nodefault (boolean ops),
58 : and c_common_truthvalue_conversion.
59 : In expr.cc: expand_expr, for operands of a MULT_EXPR.
60 : In fold-const.cc: fold.
61 : In tree.cc: get_narrower and get_unwidened.
62 :
63 : C++: in multiple-inheritance, converting between pointers may involve
64 : adjusting them by a delta stored within the class definition. */
65 :
66 : /* Subroutines of `convert'. */
67 :
68 : /* if converting pointer to pointer
69 : if dealing with classes, check for derived->base or vice versa
70 : else if dealing with method pointers, delegate
71 : else convert blindly
72 : else if converting class, pass off to build_type_conversion
73 : else try C-style pointer conversion. */
74 :
75 : static tree
76 37010160 : cp_convert_to_pointer (tree type, tree expr, bool dofold,
77 : tsubst_flags_t complain)
78 : {
79 37010160 : tree intype = TREE_TYPE (expr);
80 37010160 : enum tree_code form;
81 37010160 : tree rval;
82 37010160 : location_t loc = cp_expr_loc_or_input_loc (expr);
83 :
84 37010160 : if (intype == error_mark_node)
85 : return error_mark_node;
86 :
87 37010160 : if (MAYBE_CLASS_TYPE_P (intype))
88 : {
89 3 : intype = complete_type (intype);
90 3 : if (!COMPLETE_TYPE_P (intype))
91 : {
92 0 : if (complain & tf_error)
93 0 : error_at (loc, "cannot convert from incomplete type %qH to %qI",
94 : intype, type);
95 0 : return error_mark_node;
96 : }
97 :
98 6 : rval = build_type_conversion (type, expr);
99 3 : if (rval)
100 : {
101 0 : if ((complain & tf_error)
102 0 : && rval == error_mark_node)
103 0 : error_at (loc, "conversion of %qE from %qH to %qI is ambiguous",
104 : expr, intype, type);
105 0 : return rval;
106 : }
107 : }
108 :
109 : /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
110 37010160 : if (TYPE_PTR_P (type)
111 37010160 : && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
112 36848931 : || VOID_TYPE_P (TREE_TYPE (type))))
113 : {
114 12 : if (TYPE_PTRMEMFUNC_P (intype)
115 3409588 : || TREE_CODE (intype) == METHOD_TYPE)
116 9 : return convert_member_func_to_ptr (type, expr, complain);
117 3409576 : if (TYPE_PTR_P (TREE_TYPE (expr)))
118 2016629 : return build_nop (type, expr);
119 1392947 : intype = TREE_TYPE (expr);
120 : }
121 :
122 34993522 : if (expr == error_mark_node)
123 : return error_mark_node;
124 :
125 34993522 : form = TREE_CODE (intype);
126 :
127 34993522 : if (INDIRECT_TYPE_P (intype))
128 : {
129 23540875 : intype = TYPE_MAIN_VARIANT (intype);
130 :
131 23540875 : if (TYPE_MAIN_VARIANT (type) != intype
132 16743977 : && TYPE_PTR_P (type)
133 16735680 : && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
134 7529797 : && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
135 7446081 : && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
136 30913985 : && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
137 : {
138 7373110 : enum tree_code code = PLUS_EXPR;
139 7373110 : tree binfo;
140 7373110 : tree intype_class;
141 7373110 : tree type_class;
142 7373110 : bool same_p;
143 :
144 7373110 : intype_class = TREE_TYPE (intype);
145 7373110 : type_class = TREE_TYPE (type);
146 :
147 7373110 : same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
148 : TYPE_MAIN_VARIANT (type_class));
149 7373110 : binfo = NULL_TREE;
150 : /* Try derived to base conversion. */
151 7373110 : if (!same_p)
152 31028 : binfo = lookup_base (intype_class, type_class, ba_check,
153 : NULL, complain);
154 7373110 : if (!same_p && !binfo)
155 : {
156 : /* Try base to derived conversion. */
157 19 : binfo = lookup_base (type_class, intype_class, ba_check,
158 : NULL, complain);
159 19 : code = MINUS_EXPR;
160 : }
161 7373110 : if (binfo == error_mark_node)
162 : return error_mark_node;
163 7373101 : if (binfo || same_p)
164 : {
165 7373101 : if (binfo)
166 31019 : expr = build_base_path (code, expr, binfo, 0, complain);
167 : /* Add any qualifier conversions. */
168 7373101 : return build_nop (type, expr);
169 : }
170 : }
171 :
172 16167765 : if (TYPE_PTRMEMFUNC_P (type))
173 : {
174 0 : if (complain & tf_error)
175 0 : error_at (loc, "cannot convert %qE from type %qH to type %qI",
176 : expr, intype, type);
177 0 : return error_mark_node;
178 : }
179 :
180 16167765 : return build_nop (type, expr);
181 : }
182 1738 : else if ((TYPE_PTRDATAMEM_P (type) && TYPE_PTRDATAMEM_P (intype))
183 11454265 : || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
184 139 : return convert_ptrmem (type, expr, /*allow_inverse_p=*/false,
185 139 : /*c_cast_p=*/false, complain);
186 11452508 : else if (TYPE_PTRMEMFUNC_P (intype))
187 : {
188 0 : if (!warn_pmf2ptr)
189 : {
190 0 : if (TREE_CODE (expr) == PTRMEM_CST)
191 0 : return cp_convert_to_pointer (type, PTRMEM_CST_MEMBER (expr),
192 0 : dofold, complain);
193 0 : else if (TREE_CODE (expr) == OFFSET_REF)
194 : {
195 0 : tree object = TREE_OPERAND (expr, 0);
196 0 : return get_member_function_from_ptrfunc (&object,
197 0 : TREE_OPERAND (expr, 1),
198 : complain);
199 : }
200 : }
201 0 : if (complain & tf_error)
202 0 : error_at (loc, "cannot convert %qE from type %qH to type %qI",
203 : expr, intype, type);
204 0 : return error_mark_node;
205 : }
206 :
207 11452508 : if (null_ptr_cst_p (expr))
208 : {
209 7442618 : if (TYPE_PTRMEMFUNC_P (type))
210 650 : return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0,
211 650 : /*c_cast_p=*/false, complain);
212 :
213 7441968 : if (complain & tf_warning)
214 5162125 : maybe_warn_zero_as_null_pointer_constant (expr, loc);
215 :
216 : /* A NULL pointer-to-data-member is represented by -1, not by
217 : zero. */
218 7441968 : tree val = (TYPE_PTRDATAMEM_P (type)
219 7441968 : ? build_int_cst_type (type, -1)
220 7440350 : : build_int_cst (type, 0));
221 :
222 7441968 : return (TREE_SIDE_EFFECTS (expr)
223 7441968 : ? build2 (COMPOUND_EXPR, type, expr, val) : val);
224 : }
225 4009890 : else if (TYPE_PTRMEM_P (type) && INTEGRAL_CODE_P (form))
226 : {
227 0 : if (complain & tf_error)
228 0 : error_at (loc, "invalid conversion from %qH to %qI", intype, type);
229 0 : return error_mark_node;
230 : }
231 :
232 4009890 : if (INTEGRAL_CODE_P (form))
233 : {
234 4028507 : if (TYPE_PRECISION (intype) == POINTER_SIZE)
235 3989732 : return build1 (CONVERT_EXPR, type, expr);
236 20152 : expr = cp_convert (c_common_type_for_size (TYPE_PRECISION (type), 0), expr,
237 : complain);
238 : /* Modes may be different but sizes should be the same. There
239 : is supposed to be some integral type that is the same width
240 : as a pointer. */
241 60456 : gcc_assert (GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (TREE_TYPE (expr)))
242 : == GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type)));
243 :
244 : /* FIXME needed because convert_to_pointer_maybe_fold still folds
245 : conversion of constants. */
246 20152 : if (!dofold)
247 20152 : return build1 (CONVERT_EXPR, type, expr);
248 :
249 0 : return convert_to_pointer_maybe_fold (type, expr, dofold);
250 : }
251 :
252 6 : if (type_unknown_p (expr))
253 0 : return instantiate_type (type, expr, complain);
254 :
255 6 : if (complain & tf_error)
256 6 : error_at (loc, "cannot convert %qE from type %qH to type %qI",
257 : expr, intype, type);
258 6 : return error_mark_node;
259 : }
260 :
261 : /* Like convert, except permit conversions to take place which
262 : are not normally allowed due to access restrictions
263 : (such as conversion from sub-type to private super-type). */
264 :
265 : static tree
266 10008791 : convert_to_pointer_force (tree type, tree expr, tsubst_flags_t complain)
267 : {
268 10008791 : tree intype = TREE_TYPE (expr);
269 10008791 : enum tree_code form = TREE_CODE (intype);
270 :
271 10008791 : if (form == POINTER_TYPE)
272 : {
273 10008791 : intype = TYPE_MAIN_VARIANT (intype);
274 :
275 10008791 : if (TYPE_MAIN_VARIANT (type) != intype
276 3211874 : && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
277 3211843 : && MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
278 3211840 : && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
279 13220631 : && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
280 : {
281 3211840 : enum tree_code code = PLUS_EXPR;
282 3211840 : tree binfo;
283 :
284 3211840 : binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type),
285 : ba_unique, NULL, complain);
286 3211840 : if (!binfo)
287 : {
288 3 : binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype),
289 : ba_unique, NULL, complain);
290 3 : code = MINUS_EXPR;
291 : }
292 3211840 : if (binfo == error_mark_node)
293 : return error_mark_node;
294 3211840 : if (binfo)
295 : {
296 3211837 : expr = build_base_path (code, expr, binfo, 0, complain);
297 3211837 : if (expr == error_mark_node)
298 : return error_mark_node;
299 : /* Add any qualifier conversions. */
300 3211837 : if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)),
301 : TREE_TYPE (type)))
302 370432 : expr = build_nop (type, expr);
303 3211837 : return expr;
304 : }
305 : }
306 : }
307 :
308 6796954 : return cp_convert_to_pointer (type, expr, /*fold*/false, complain);
309 : }
310 :
311 : /* We are passing something to a function which requires a reference.
312 : The type we are interested in is in TYPE. The initial
313 : value we have to begin with is in ARG.
314 :
315 : FLAGS controls how we manage access checking.
316 : DIRECT_BIND in FLAGS controls how any temporaries are generated.
317 : If DIRECT_BIND is set, DECL is the reference we're binding to. */
318 :
319 : static tree
320 248 : build_up_reference (tree type, tree arg, int flags, tree decl,
321 : tsubst_flags_t complain)
322 : {
323 248 : tree rval;
324 248 : tree argtype = TREE_TYPE (arg);
325 248 : tree target_type = TREE_TYPE (type);
326 :
327 248 : gcc_assert (TYPE_REF_P (type));
328 :
329 248 : if ((flags & DIRECT_BIND) && ! lvalue_p (arg))
330 : {
331 : /* Create a new temporary variable. We can't just use a TARGET_EXPR
332 : here because it needs to live as long as DECL. */
333 0 : tree targ = arg;
334 :
335 0 : arg = make_temporary_var_for_ref_to_temp (decl, target_type);
336 :
337 : /* Process the initializer for the declaration. */
338 0 : DECL_INITIAL (arg) = targ;
339 0 : cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE,
340 : LOOKUP_ONLYCONVERTING|DIRECT_BIND);
341 : }
342 248 : else if (!(flags & DIRECT_BIND) && ! obvalue_p (arg))
343 1 : return get_target_expr (arg, complain);
344 :
345 : /* If we had a way to wrap this up, and say, if we ever needed its
346 : address, transform all occurrences of the register, into a memory
347 : reference we could win better. */
348 247 : rval = cp_build_addr_expr (arg, complain);
349 247 : if (rval == error_mark_node)
350 : return error_mark_node;
351 :
352 247 : if ((flags & LOOKUP_PROTECT)
353 247 : && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type)
354 9 : && MAYBE_CLASS_TYPE_P (argtype)
355 256 : && MAYBE_CLASS_TYPE_P (target_type))
356 : {
357 : /* We go through lookup_base for the access control. */
358 9 : tree binfo = lookup_base (argtype, target_type, ba_check,
359 : NULL, complain);
360 9 : if (binfo == error_mark_node)
361 : return error_mark_node;
362 9 : if (binfo == NULL_TREE)
363 0 : return error_not_base_type (target_type, argtype);
364 9 : rval = build_base_path (PLUS_EXPR, rval, binfo, 1, complain);
365 : }
366 : else
367 238 : rval
368 238 : = convert_to_pointer_force (build_pointer_type (target_type),
369 : rval, complain);
370 247 : return build_nop (type, rval);
371 : }
372 :
373 : /* Subroutine of convert_to_reference. REFTYPE is the target reference type.
374 : INTYPE is the original rvalue type and DECL is an optional _DECL node
375 : for diagnostics.
376 :
377 : [dcl.init.ref] says that if an rvalue is used to
378 : initialize a reference, then the reference must be to a
379 : non-volatile const type. */
380 :
381 : static void
382 7 : diagnose_ref_binding (location_t loc, tree reftype, tree intype, tree decl)
383 : {
384 7 : tree ttl = TREE_TYPE (reftype);
385 :
386 7 : if (!TYPE_REF_IS_RVALUE (reftype)
387 7 : && !CP_TYPE_CONST_NON_VOLATILE_P (ttl))
388 : {
389 0 : const char *msg;
390 :
391 0 : if (CP_TYPE_VOLATILE_P (ttl) && decl)
392 : msg = G_("initialization of volatile reference type %q#T from "
393 : "rvalue of type %qT");
394 0 : else if (CP_TYPE_VOLATILE_P (ttl))
395 : msg = G_("conversion to volatile reference type %q#T "
396 : "from rvalue of type %qT");
397 0 : else if (decl)
398 : msg = G_("initialization of non-const reference type %q#T from "
399 : "rvalue of type %qT");
400 : else
401 0 : msg = G_("conversion to non-const reference type %q#T from "
402 : "rvalue of type %qT");
403 :
404 0 : permerror (loc, msg, reftype, intype);
405 : }
406 7 : }
407 :
408 : /* For C++: Only need to do one-level references, but cannot
409 : get tripped up on signed/unsigned differences.
410 :
411 : DECL is either NULL_TREE or the _DECL node for a reference that is being
412 : initialized. It can be error_mark_node if we don't know the _DECL but
413 : we know it's an initialization. */
414 :
415 : tree
416 250 : convert_to_reference (tree reftype, tree expr, int convtype,
417 : int flags, tree decl, tsubst_flags_t complain)
418 : {
419 250 : tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype));
420 250 : tree intype;
421 250 : tree rval = NULL_TREE;
422 250 : tree rval_as_conversion = NULL_TREE;
423 250 : bool can_convert_intype_to_type;
424 250 : location_t loc = cp_expr_loc_or_input_loc (expr);
425 :
426 250 : if (TREE_CODE (type) == FUNCTION_TYPE
427 250 : && TREE_TYPE (expr) == unknown_type_node)
428 0 : expr = instantiate_type (type, expr, complain);
429 :
430 250 : if (expr == error_mark_node)
431 : return error_mark_node;
432 :
433 248 : intype = TREE_TYPE (expr);
434 :
435 248 : gcc_assert (!TYPE_REF_P (intype));
436 248 : gcc_assert (TYPE_REF_P (reftype));
437 :
438 248 : intype = TYPE_MAIN_VARIANT (intype);
439 :
440 248 : can_convert_intype_to_type = can_convert_standard (type, intype, complain);
441 :
442 248 : if (!can_convert_intype_to_type
443 4 : && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype)
444 248 : && ! (flags & LOOKUP_NO_CONVERSION))
445 : {
446 : /* Look for a user-defined conversion to lvalue that we can use. */
447 :
448 0 : rval_as_conversion
449 0 : = build_type_conversion (reftype, expr);
450 :
451 0 : if (rval_as_conversion && rval_as_conversion != error_mark_node
452 0 : && lvalue_p (rval_as_conversion))
453 : {
454 : expr = rval_as_conversion;
455 248 : rval_as_conversion = NULL_TREE;
456 : intype = type;
457 : can_convert_intype_to_type = 1;
458 : }
459 : }
460 :
461 248 : if (((convtype & CONV_STATIC)
462 0 : && can_convert_standard (intype, type, complain))
463 248 : || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type))
464 : {
465 244 : {
466 244 : tree ttl = TREE_TYPE (reftype);
467 244 : tree ttr = lvalue_type (expr);
468 :
469 244 : if ((complain & tf_error)
470 244 : && ! lvalue_p (expr))
471 3 : diagnose_ref_binding (loc, reftype, intype, decl);
472 :
473 244 : if (! (convtype & CONV_CONST)
474 244 : && !at_least_as_qualified_p (ttl, ttr))
475 : {
476 6 : if (complain & tf_error)
477 6 : permerror (loc, "conversion from %qH to %qI discards qualifiers",
478 : ttr, reftype);
479 : else
480 0 : return error_mark_node;
481 : }
482 : }
483 :
484 244 : return build_up_reference (reftype, expr, flags, decl, complain);
485 : }
486 4 : else if ((convtype & CONV_REINTERPRET) && obvalue_p (expr))
487 : {
488 : /* When casting an lvalue to a reference type, just convert into
489 : a pointer to the new type and deference it. This is allowed
490 : by San Diego WP section 5.2.9 paragraph 12, though perhaps it
491 : should be done directly (jason). (int &)ri ---> *(int*)&ri */
492 :
493 : /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
494 : meant. */
495 0 : if ((complain & tf_warning)
496 0 : && TYPE_PTR_P (intype)
497 0 : && (comptypes (TREE_TYPE (intype), type,
498 : COMPARE_BASE | COMPARE_DERIVED)))
499 0 : warning_at (loc, 0, "casting %qT to %qT does not dereference pointer",
500 : intype, reftype);
501 :
502 0 : rval = cp_build_addr_expr (expr, complain);
503 0 : if (rval != error_mark_node)
504 0 : rval = convert_force (build_pointer_type (TREE_TYPE (reftype)),
505 : rval, 0, complain);
506 0 : if (rval != error_mark_node)
507 0 : rval = build1 (NOP_EXPR, reftype, rval);
508 : }
509 : else
510 : {
511 4 : rval = convert_for_initialization (NULL_TREE, type, expr, flags,
512 : ICR_CONVERTING, 0, 0, complain);
513 4 : if (rval == NULL_TREE || rval == error_mark_node)
514 : return rval;
515 4 : if (complain & tf_error)
516 4 : diagnose_ref_binding (loc, reftype, intype, decl);
517 4 : rval = build_up_reference (reftype, rval, flags, decl, complain);
518 : }
519 :
520 4 : if (rval)
521 : {
522 : /* If we found a way to convert earlier, then use it. */
523 : return rval;
524 : }
525 :
526 0 : if (complain & tf_error)
527 0 : error_at (loc, "cannot convert type %qH to type %qI", intype, reftype);
528 :
529 0 : return error_mark_node;
530 : }
531 :
532 : /* We are using a reference VAL for its value. Bash that reference all the
533 : way down to its lowest form. */
534 :
535 : tree
536 2461031096 : convert_from_reference (tree val)
537 : {
538 2461031096 : if (TREE_TYPE (val)
539 2461031096 : && TYPE_REF_P (TREE_TYPE (val)))
540 : {
541 271068833 : tree t = TREE_TYPE (TREE_TYPE (val));
542 271068833 : tree ref = build1 (INDIRECT_REF, t, val);
543 :
544 271068833 : mark_exp_read (val);
545 : /* We *must* set TREE_READONLY when dereferencing a pointer to const,
546 : so that we get the proper error message if the result is used
547 : to assign to. Also, &* is supposed to be a no-op. */
548 271068833 : TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
549 271068833 : TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
550 271068833 : TREE_SIDE_EFFECTS (ref)
551 271068833 : = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val));
552 271068833 : val = ref;
553 : }
554 :
555 2461031096 : return val;
556 : }
557 :
558 : /* Really perform an lvalue-to-rvalue conversion, including copying an
559 : argument of class type into a temporary. */
560 :
561 : tree
562 36987553 : force_rvalue (tree expr, tsubst_flags_t complain)
563 : {
564 36987553 : tree type = TREE_TYPE (expr);
565 36987553 : if (MAYBE_CLASS_TYPE_P (type) && TREE_CODE (expr) != TARGET_EXPR)
566 : {
567 141322 : releasing_vec args (make_tree_vector_single (expr));
568 141322 : expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
569 : &args, type, LOOKUP_NORMAL, complain);
570 141322 : expr = build_cplus_new (type, expr, complain);
571 141322 : }
572 : else
573 36846231 : expr = decay_conversion (expr, complain);
574 :
575 36987553 : return expr;
576 : }
577 :
578 : /* Force EXPR to be an lvalue, if it isn't already. */
579 :
580 : tree
581 524661 : force_lvalue (tree expr, tsubst_flags_t complain)
582 : {
583 524661 : if (!lvalue_p (expr))
584 : {
585 27 : expr = cp_build_addr_expr (expr, complain);
586 27 : expr = cp_build_indirect_ref (input_location, expr, RO_ARROW, complain);
587 : }
588 524661 : return expr;
589 : }
590 :
591 :
592 : /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has
593 : TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR
594 : unchanged. */
595 :
596 : static tree
597 230175766 : ignore_overflows (tree expr, tree orig)
598 : {
599 230175766 : tree stripped_expr = tree_strip_any_location_wrapper (expr);
600 230175766 : tree stripped_orig = tree_strip_any_location_wrapper (orig);
601 :
602 230175766 : if (TREE_CODE (stripped_expr) == INTEGER_CST
603 154689203 : && TREE_CODE (stripped_orig) == INTEGER_CST
604 384862222 : && TREE_OVERFLOW (stripped_expr) != TREE_OVERFLOW (stripped_orig))
605 : {
606 4451 : gcc_assert (!TREE_OVERFLOW (stripped_orig));
607 : /* Ensure constant sharing. */
608 4451 : stripped_expr = wide_int_to_tree (TREE_TYPE (stripped_expr),
609 8902 : wi::to_wide (stripped_expr));
610 : }
611 :
612 230175766 : return preserve_any_location_wrapper (stripped_expr, expr);
613 : }
614 :
615 : /* Fold away simple conversions, but make sure TREE_OVERFLOW is set
616 : properly and propagate TREE_NO_WARNING if folding EXPR results
617 : in the same expression code. */
618 :
619 : tree
620 69559123 : cp_fold_convert (tree type, tree expr)
621 : {
622 69559123 : tree conv;
623 69559123 : if (TREE_TYPE (expr) == type)
624 : conv = expr;
625 28114290 : else if ((TREE_CODE (expr) == PTRMEM_CST
626 263 : && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type),
627 : PTRMEM_CST_CLASS (expr)))
628 28114293 : || (REFLECT_EXPR_P (expr) && REFLECTION_TYPE_P (type)))
629 : {
630 : /* Avoid wrapping a PTRMEM_CST/REFLECT_EXPR in NOP_EXPR. */
631 262 : conv = copy_node (expr);
632 262 : TREE_TYPE (conv) = type;
633 : }
634 28114028 : else if (TYPE_PTRMEM_P (type))
635 : {
636 6 : conv = convert_ptrmem (type, expr, true, false,
637 : tf_warning_or_error);
638 6 : conv = cp_fully_fold (conv);
639 : }
640 : else
641 : {
642 28114022 : conv = fold_convert (type, expr);
643 28114022 : conv = ignore_overflows (conv, expr);
644 : }
645 :
646 69559123 : if (TREE_CODE (expr) == TREE_CODE (conv))
647 42898670 : copy_warning (conv, expr);
648 :
649 69559123 : return conv;
650 : }
651 :
652 : /* C++ conversions, preference to static cast conversions. */
653 :
654 : tree
655 329200093 : cp_convert (tree type, tree expr, tsubst_flags_t complain)
656 : {
657 329200093 : return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL, complain);
658 : }
659 :
660 : /* C++ equivalent of convert_and_check but using cp_convert as the
661 : conversion function.
662 :
663 : Convert EXPR to TYPE, warning about conversion problems with constants.
664 : Invoke this function on every expression that is converted implicitly,
665 : i.e. because of language rules and not because of an explicit cast. */
666 :
667 : tree
668 108086977 : cp_convert_and_check (tree type, tree expr, tsubst_flags_t complain)
669 : {
670 108086977 : tree result, expr_for_warning = expr;
671 :
672 108086977 : if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR)
673 117 : expr = TREE_OPERAND (expr, 0);
674 108086977 : if (TREE_TYPE (expr) == type)
675 : return expr;
676 108086964 : if (expr == error_mark_node)
677 : return expr;
678 108086964 : result = cp_convert (type, expr, complain);
679 :
680 108086964 : if ((complain & tf_warning)
681 100636339 : && c_inhibit_evaluation_warnings == 0)
682 : {
683 98981766 : tree folded = cp_fully_fold (expr_for_warning);
684 98981766 : tree folded_result;
685 98981766 : if (folded == expr)
686 : folded_result = result;
687 : else
688 : {
689 : /* Avoid bogus -Wparentheses warnings. */
690 35868563 : warning_sentinel w (warn_parentheses);
691 35868563 : warning_sentinel c (warn_int_in_bool_context);
692 35868563 : folded_result = cp_convert (type, folded, tf_none);
693 35868563 : }
694 98981766 : folded_result = fold_simple (folded_result);
695 85514567 : if (!TREE_OVERFLOW_P (folded)
696 184496330 : && folded_result != error_mark_node)
697 159210686 : warnings_for_convert_and_check (cp_expr_loc_or_input_loc (expr),
698 : type, folded, folded_result);
699 : }
700 :
701 : return result;
702 : }
703 :
704 : /* Conversion...
705 :
706 : FLAGS indicates how we should behave. */
707 :
708 : tree
709 506122930 : ocp_convert (tree type, tree expr, int convtype, int flags,
710 : tsubst_flags_t complain)
711 : {
712 506122930 : tree e = expr;
713 506122930 : enum tree_code code = TREE_CODE (type);
714 506122930 : const char *invalid_conv_diag;
715 506122930 : tree e1;
716 506122930 : location_t loc = cp_expr_loc_or_input_loc (expr);
717 506122930 : bool dofold = (convtype & CONV_FOLD);
718 :
719 506122930 : if (error_operand_p (e) || type == error_mark_node)
720 91 : return error_mark_node;
721 :
722 506122839 : if (TREE_CODE (e) == COMPOUND_EXPR)
723 : {
724 482843 : e = ocp_convert (type, TREE_OPERAND (e, 1), convtype, flags, complain);
725 482843 : if (e == error_mark_node)
726 : return error_mark_node;
727 482843 : if (e == TREE_OPERAND (expr, 1))
728 : return expr;
729 480632 : e = build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR, TREE_TYPE (e),
730 480632 : TREE_OPERAND (expr, 0), e);
731 480632 : copy_warning (e, expr);
732 480632 : return e;
733 : }
734 :
735 505639996 : complete_type (type);
736 505639996 : complete_type (TREE_TYPE (expr));
737 :
738 1011279992 : if ((invalid_conv_diag
739 505639996 : = targetm.invalid_conversion (TREE_TYPE (expr), type)))
740 : {
741 0 : if (complain & tf_error)
742 0 : error (invalid_conv_diag);
743 0 : return error_mark_node;
744 : }
745 :
746 : /* FIXME remove when moving to c_fully_fold model. */
747 505639996 : if (!CLASS_TYPE_P (type))
748 : {
749 478074830 : e = mark_rvalue_use (e);
750 478074830 : tree v = scalar_constant_value (e);
751 478074830 : if (!error_operand_p (v))
752 478074769 : e = v;
753 : }
754 505639996 : if (error_operand_p (e))
755 0 : return error_mark_node;
756 :
757 505639996 : if (NULLPTR_TYPE_P (type) && null_ptr_cst_p (e))
758 : {
759 5208 : if (complain & tf_warning)
760 2734 : maybe_warn_zero_as_null_pointer_constant (e, loc);
761 :
762 5208 : if (!TREE_SIDE_EFFECTS (e))
763 5197 : return nullptr_node;
764 : }
765 :
766 505634799 : if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP))
767 : /* We need a new temporary; don't take this shortcut. */;
768 504122796 : else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e)))
769 : {
770 243036790 : tree etype = TREE_TYPE (e);
771 243036790 : if (same_type_p (type, etype))
772 : /* The call to fold will not always remove the NOP_EXPR as
773 : might be expected, since if one of the types is a typedef;
774 : the comparison in fold is just equality of pointers, not a
775 : call to comptypes. We don't call fold in this case because
776 : that can result in infinite recursion; fold will call
777 : convert, which will call ocp_convert, etc. */
778 : return e;
779 : /* For complex data types, we need to perform componentwise
780 : conversion. */
781 22614505 : else if (TREE_CODE (type) == COMPLEX_TYPE)
782 0 : return convert_to_complex_maybe_fold (type, e, dofold);
783 22614505 : else if (VECTOR_TYPE_P (type))
784 3851 : return convert_to_vector (type, rvalue (e));
785 22610654 : else if (TREE_CODE (e) == TARGET_EXPR)
786 : {
787 : /* Don't build a NOP_EXPR of class type. Instead, change the
788 : type of the temporary. */
789 206546 : gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, etype));
790 206546 : TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type;
791 206546 : return e;
792 : }
793 22404108 : else if (TREE_CODE (e) == CONSTRUCTOR)
794 : {
795 66 : gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, etype));
796 66 : TREE_TYPE (e) = type;
797 66 : return e;
798 : }
799 : else
800 : {
801 : /* We shouldn't be treating objects of ADDRESSABLE type as
802 : rvalues. */
803 22404042 : gcc_assert (!TREE_ADDRESSABLE (type));
804 22404042 : return build_nop (type, e);
805 : }
806 : }
807 :
808 262598009 : e1 = targetm.convert_to_type (type, e);
809 262598009 : if (e1)
810 : return e1;
811 :
812 262598009 : if (code == VOID_TYPE && (convtype & CONV_STATIC))
813 : {
814 37764 : e = convert_to_void (e, ICV_CAST, complain);
815 37764 : return e;
816 : }
817 :
818 262560245 : if (INTEGRAL_CODE_P (code))
819 : {
820 210450899 : tree intype = TREE_TYPE (e);
821 210450899 : tree converted;
822 :
823 210450899 : if (TREE_CODE (type) == ENUMERAL_TYPE)
824 : {
825 : /* enum = enum, enum = int, enum = float, (enum)pointer are all
826 : errors. */
827 725288 : if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype)
828 21 : || SCALAR_FLOAT_TYPE_P (intype))
829 725288 : && ! (convtype & CONV_STATIC))
830 725288 : || TYPE_PTR_P (intype))
831 : {
832 0 : if (complain & tf_error)
833 0 : permerror (loc, "conversion from %q#T to %q#T", intype, type);
834 : else
835 0 : return error_mark_node;
836 : }
837 :
838 : /* [expr.static.cast]
839 :
840 : 8. A value of integral or enumeration type can be explicitly
841 : converted to a complete enumeration type. If the enumeration
842 : type has a fixed underlying type, the value is first converted
843 : to that type by integral promotion or integral conversion, if
844 : necessary, and then to the enumeration type. If the
845 : enumeration type does not have a fixed underlying type, the
846 : value is unchanged if the original value is within the range
847 : of the enumeration values, and otherwise, the behavior is
848 : undefined. A value of floating-point type can also be
849 : explicitly converted to an enumeration type. The resulting
850 : value is the same as converting the original value to the
851 : underlying type of the enumeration, and subsequently to the
852 : enumeration type. */
853 725288 : if ((ENUM_FIXED_UNDERLYING_TYPE_P (type)
854 557979 : && INTEGRAL_OR_ENUMERATION_TYPE_P (intype))
855 725303 : || SCALAR_FLOAT_TYPE_P (intype))
856 : {
857 557985 : e = ocp_convert (ENUM_UNDERLYING_TYPE (type), e, convtype,
858 : flags, complain);
859 557985 : if (e == error_mark_node)
860 : return error_mark_node;
861 : }
862 :
863 725288 : tree val = fold_for_warn (e);
864 725288 : if ((complain & tf_warning)
865 724290 : && TREE_CODE (val) == INTEGER_CST
866 30669 : && ENUM_UNDERLYING_TYPE (type)
867 755954 : && !int_fits_type_p (val, ENUM_UNDERLYING_TYPE (type)))
868 116 : warning_at (loc, OPT_Wconversion,
869 : "the result of the conversion is unspecified because "
870 : "%qE is outside the range of type %qT",
871 : expr, type);
872 : }
873 210450899 : if (MAYBE_CLASS_TYPE_P (intype))
874 : {
875 9 : tree rval;
876 18 : rval = build_type_conversion (type, e);
877 9 : if (rval)
878 : return rval;
879 0 : if (complain & tf_error)
880 0 : error_at (loc, "%q#T used where a %qT was expected", intype, type);
881 0 : return error_mark_node;
882 : }
883 210450890 : if (code == BOOLEAN_TYPE)
884 : {
885 8389146 : if (VOID_TYPE_P (intype))
886 : {
887 18 : if (complain & tf_error)
888 18 : error_at (loc,
889 : "could not convert %qE from %<void%> to %<bool%>",
890 : expr);
891 18 : return error_mark_node;
892 : }
893 :
894 8389128 : if (VECTOR_TYPE_P (intype) && !gnu_vector_type_p (intype))
895 : {
896 0 : if (complain & tf_error)
897 0 : error_at (loc, "could not convert %qE from %qH to %qI", expr,
898 0 : TREE_TYPE (expr), type);
899 0 : return error_mark_node;
900 : }
901 :
902 : /* We can't implicitly convert a scoped enum to bool, so convert
903 : to the underlying type first. */
904 8389128 : if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC))
905 115 : e = build_nop (ENUM_UNDERLYING_TYPE (intype), e);
906 8389128 : if (complain & tf_warning)
907 4991636 : e = cp_truthvalue_conversion (e, complain);
908 : else
909 : {
910 : /* Prevent bogus -Wint-in-bool-context warnings coming
911 : from c_common_truthvalue_conversion down the line. */
912 3397492 : warning_sentinel w (warn_int_in_bool_context);
913 3397492 : warning_sentinel c (warn_sign_compare);
914 3397492 : e = cp_truthvalue_conversion (e, complain);
915 3397492 : }
916 :
917 : /* Sometimes boolean types don't match if a non-standard boolean
918 : type has been invented by the target. */
919 8389128 : if (tree e2 = targetm.convert_to_type (type, e))
920 : return e2;
921 :
922 8389128 : return e;
923 : }
924 :
925 202061744 : converted = convert_to_integer_maybe_fold (type, e, dofold);
926 :
927 : /* Ignore any integer overflow caused by the conversion. */
928 202061744 : return ignore_overflows (converted, e);
929 : }
930 52109346 : if (INDIRECT_TYPE_P (type) || TYPE_PTRMEM_P (type))
931 30213206 : return cp_convert_to_pointer (type, e, dofold, complain);
932 21896140 : if (code == VECTOR_TYPE)
933 : {
934 5137 : tree in_vtype = TREE_TYPE (e);
935 5137 : if (MAYBE_CLASS_TYPE_P (in_vtype))
936 : {
937 0 : tree ret_val;
938 0 : ret_val = build_type_conversion (type, e);
939 0 : if (ret_val)
940 : return ret_val;
941 0 : if (complain & tf_error)
942 0 : error_at (loc, "%q#T used where a %qT was expected",
943 : in_vtype, type);
944 0 : return error_mark_node;
945 : }
946 5137 : return convert_to_vector (type, rvalue (e));
947 : }
948 21891003 : if (code == REAL_TYPE || code == COMPLEX_TYPE)
949 : {
950 20378994 : if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e)))
951 : {
952 0 : tree rval;
953 0 : rval = build_type_conversion (type, e);
954 0 : if (rval)
955 : return rval;
956 0 : else if (complain & tf_error)
957 0 : error_at (loc,
958 : "%q#T used where a floating-point value was expected",
959 0 : TREE_TYPE (e));
960 : }
961 20378994 : if (code == REAL_TYPE)
962 19976964 : return convert_to_real_maybe_fold (type, e, dofold);
963 402030 : else if (code == COMPLEX_TYPE)
964 402030 : return convert_to_complex_maybe_fold (type, e, dofold);
965 : }
966 :
967 : /* New C++ semantics: since assignment is now based on
968 : memberwise copying, if the rhs type is derived from the
969 : lhs type, then we may still do a conversion. */
970 1512009 : if (RECORD_OR_UNION_CODE_P (code))
971 : {
972 1512003 : tree dtype = TREE_TYPE (e);
973 1512003 : tree ctor = NULL_TREE;
974 :
975 1512003 : dtype = TYPE_MAIN_VARIANT (dtype);
976 :
977 : /* Conversion between aggregate types. New C++ semantics allow
978 : objects of derived type to be cast to objects of base type.
979 : Old semantics only allowed this between pointers.
980 :
981 : There may be some ambiguity between using a constructor
982 : vs. using a type conversion operator when both apply. */
983 :
984 1512003 : ctor = e;
985 :
986 1512003 : if (abstract_virtuals_error (NULL_TREE, type, complain))
987 9 : return error_mark_node;
988 :
989 1098 : if (BRACE_ENCLOSED_INITIALIZER_P (ctor)
990 : /* We don't want to create a TARGET_EXPR in a template by the
991 : build_cplus_new below. */
992 1512003 : || processing_template_decl)
993 19845 : ctor = perform_implicit_conversion_flags (type, ctor, complain, flags);
994 1492149 : else if ((flags & LOOKUP_ONLYCONVERTING)
995 1492149 : && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype)))
996 : /* For copy-initialization, first we create a temp of the proper type
997 : with a user-defined conversion sequence, then we direct-initialize
998 : the target with the temp (see [dcl.init]). */
999 23460 : ctor = build_user_type_conversion (type, ctor, flags, complain);
1000 : else
1001 : {
1002 1468689 : releasing_vec ctor_vec (make_tree_vector_single (ctor));
1003 1468689 : ctor = build_special_member_call (NULL_TREE,
1004 : complete_ctor_identifier,
1005 : &ctor_vec,
1006 : type, flags, complain);
1007 1468689 : }
1008 1511994 : if (ctor)
1009 1511767 : return build_cplus_new (type, ctor, complain);
1010 : }
1011 :
1012 233 : if (complain & tf_error)
1013 : {
1014 : /* If the conversion failed and expr was an invalid use of pointer to
1015 : member function, try to report a meaningful error. */
1016 233 : if (invalid_nonstatic_memfn_p (loc, expr, complain))
1017 : /* We displayed the error message. */;
1018 : else
1019 : {
1020 230 : auto_diagnostic_group d;
1021 230 : error_at (loc, "conversion from %qH to non-scalar type %qI requested",
1022 230 : TREE_TYPE (expr), type);
1023 230 : maybe_show_nonconverting_candidate (type, TREE_TYPE (expr), expr,
1024 : flags);
1025 230 : }
1026 : }
1027 233 : return error_mark_node;
1028 : }
1029 :
1030 : /* If CALL is a call, return the callee; otherwise null. */
1031 :
1032 : tree
1033 1371418572 : cp_get_callee (tree call)
1034 : {
1035 1371418572 : if (call == NULL_TREE)
1036 : return call;
1037 1371418572 : else if (TREE_CODE (call) == CALL_EXPR)
1038 1246298971 : return CALL_EXPR_FN (call);
1039 125119601 : else if (TREE_CODE (call) == AGGR_INIT_EXPR)
1040 52597512 : return AGGR_INIT_EXPR_FN (call);
1041 : return NULL_TREE;
1042 : }
1043 :
1044 : /* FN is the callee of a CALL_EXPR or AGGR_INIT_EXPR; return the FUNCTION_DECL
1045 : if we can. */
1046 :
1047 : tree
1048 1143010367 : cp_get_fndecl_from_callee (tree fn, bool fold /* = true */)
1049 : {
1050 1143010367 : if (fn == NULL_TREE)
1051 : return fn;
1052 :
1053 : /* We evaluate constexpr functions on the original, pre-genericization
1054 : bodies. So block-scope extern declarations have not been mapped to
1055 : declarations in outer scopes. Use the namespace-scope declaration,
1056 : if any, so that retrieve_constexpr_fundef can find it (PR111132). */
1057 2110936155 : auto fn_or_local_alias = [] (tree f)
1058 : {
1059 1025275037 : if (DECL_LOCAL_DECL_P (f))
1060 58380 : if (tree alias = DECL_LOCAL_DECL_ALIAS (f))
1061 58380 : if (alias != error_mark_node)
1062 58380 : return alias;
1063 : return f;
1064 : };
1065 :
1066 1085661118 : if (TREE_CODE (fn) == FUNCTION_DECL)
1067 11754478 : return fn_or_local_alias (fn);
1068 1073906640 : tree type = TREE_TYPE (fn);
1069 1073906640 : if (type == NULL_TREE || !INDIRECT_TYPE_P (type))
1070 : return NULL_TREE;
1071 1023809809 : if (fold)
1072 3681714 : fn = maybe_constant_init (fn);
1073 1023809809 : STRIP_NOPS (fn);
1074 1023809809 : if (TREE_CODE (fn) == ADDR_EXPR
1075 1023809809 : || TREE_CODE (fn) == FDESC_EXPR)
1076 1013521495 : fn = TREE_OPERAND (fn, 0);
1077 1023809809 : if (TREE_CODE (fn) == FUNCTION_DECL)
1078 1013520559 : return fn_or_local_alias (fn);
1079 : return NULL_TREE;
1080 : }
1081 :
1082 : /* Like get_callee_fndecl, but handles AGGR_INIT_EXPR as well and uses the
1083 : constexpr machinery. */
1084 :
1085 : tree
1086 0 : cp_get_callee_fndecl (tree call)
1087 : {
1088 0 : return cp_get_fndecl_from_callee (cp_get_callee (call));
1089 : }
1090 :
1091 : /* As above, but not using the constexpr machinery. */
1092 :
1093 : tree
1094 450509935 : cp_get_callee_fndecl_nofold (tree call)
1095 : {
1096 450509935 : return cp_get_fndecl_from_callee (cp_get_callee (call), false);
1097 : }
1098 :
1099 : /* Subroutine of convert_to_void. Warn if we're discarding something with
1100 : attribute [[nodiscard]]. */
1101 :
1102 : static void
1103 6253178 : maybe_warn_nodiscard (tree expr, impl_conv_void implicit)
1104 : {
1105 6253178 : if (!warn_unused_result || c_inhibit_evaluation_warnings)
1106 : return;
1107 :
1108 6242768 : tree call = expr;
1109 6242768 : if (TREE_CODE (expr) == TARGET_EXPR)
1110 131791 : call = TARGET_EXPR_INITIAL (expr);
1111 6242768 : location_t loc = cp_expr_loc_or_input_loc (call);
1112 6242768 : tree callee = cp_get_callee (call);
1113 6242768 : if (!callee || !TREE_TYPE (callee))
1114 : return;
1115 :
1116 6240762 : tree type = TREE_TYPE (callee);
1117 6240762 : if (TYPE_PTRMEMFUNC_P (type))
1118 0 : type = TYPE_PTRMEMFUNC_FN_TYPE (type);
1119 6240762 : if (INDIRECT_TYPE_P (type))
1120 3681714 : type = TREE_TYPE (type);
1121 6240762 : if (!FUNC_OR_METHOD_TYPE_P (type))
1122 : return;
1123 :
1124 6212149 : tree rettype = TREE_TYPE (type);
1125 6212149 : tree fn = cp_get_fndecl_from_callee (callee);
1126 6212149 : tree attr;
1127 6212149 : if (implicit != ICV_CAST && fn
1128 6212149 : && (attr = lookup_attribute ("nodiscard", DECL_ATTRIBUTES (fn))))
1129 : {
1130 398 : escaped_string msg;
1131 398 : tree args = TREE_VALUE (attr);
1132 398 : if (args)
1133 63 : msg.escape (TREE_STRING_POINTER (TREE_VALUE (args)));
1134 398 : const char *format
1135 398 : = (msg
1136 398 : ? G_("ignoring return value of %qD, "
1137 : "declared with attribute %<nodiscard%>: %qs")
1138 : : G_("ignoring return value of %qD, "
1139 335 : "declared with attribute %<nodiscard%>%s"));
1140 398 : const char *raw_msg = msg ? (const char *) msg : "";
1141 398 : auto_diagnostic_group d;
1142 398 : auto_urlify_attributes sentinel;
1143 398 : if (warning_at (loc, OPT_Wunused_result, format, fn, raw_msg))
1144 398 : inform (DECL_SOURCE_LOCATION (fn), "declared here");
1145 398 : }
1146 6211751 : else if (implicit != ICV_CAST
1147 6211751 : && (attr = lookup_attribute ("nodiscard", TYPE_ATTRIBUTES (rettype))))
1148 : {
1149 121 : escaped_string msg;
1150 121 : tree args = TREE_VALUE (attr);
1151 121 : if (args)
1152 54 : msg.escape (TREE_STRING_POINTER (TREE_VALUE (args)));
1153 121 : const char *format
1154 121 : = (msg
1155 121 : ? G_("ignoring returned value of type %qT, "
1156 : "declared with attribute %<nodiscard%>: %qs")
1157 : : G_("ignoring returned value of type %qT, "
1158 67 : "declared with attribute %<nodiscard%>%s"));
1159 121 : const char *raw_msg = msg ? (const char *) msg : "";
1160 121 : auto_diagnostic_group d;
1161 121 : auto_urlify_attributes sentinel;
1162 121 : if (warning_at (loc, OPT_Wunused_result, format, rettype, raw_msg))
1163 : {
1164 121 : if (fn)
1165 22 : inform (DECL_SOURCE_LOCATION (fn),
1166 : "in call to %qD, declared here", fn);
1167 121 : inform (DECL_SOURCE_LOCATION (TYPE_NAME (rettype)),
1168 : "%qT declared here", rettype);
1169 : }
1170 121 : }
1171 6211630 : else if (TREE_CODE (expr) == TARGET_EXPR
1172 6211630 : && lookup_attribute ("warn_unused_result", TYPE_ATTRIBUTES (type)))
1173 : {
1174 : /* The TARGET_EXPR confuses do_warn_unused_result into thinking that the
1175 : result is used, so handle that case here. */
1176 63 : auto_urlify_attributes sentinel;
1177 63 : if (fn)
1178 : {
1179 63 : auto_diagnostic_group d;
1180 63 : if (warning_at (loc, OPT_Wunused_result,
1181 : "ignoring return value of %qD, "
1182 : "declared with attribute %<warn_unused_result%>",
1183 : fn))
1184 63 : inform (DECL_SOURCE_LOCATION (fn), "declared here");
1185 63 : }
1186 : else
1187 0 : warning_at (loc, OPT_Wunused_result,
1188 : "ignoring return value of function "
1189 : "declared with attribute %<warn_unused_result%>");
1190 63 : }
1191 : }
1192 :
1193 : /* When an expression is used in a void context, its value is discarded and
1194 : no lvalue-rvalue and similar conversions happen [expr.static.cast/4,
1195 : stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type
1196 : in a void context. The C++ standard does not define what an `access' to an
1197 : object is, but there is reason to believe that it is the lvalue to rvalue
1198 : conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it
1199 : accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8
1200 : indicates that volatile semantics should be the same between C and C++
1201 : where ever possible. C leaves it implementation defined as to what
1202 : constitutes an access to a volatile. So, we interpret `*vp' as a read of
1203 : the volatile object `vp' points to, unless that is an incomplete type. For
1204 : volatile references we do not do this interpretation, because that would
1205 : make it impossible to ignore the reference return value from functions. We
1206 : issue warnings in the confusing cases.
1207 :
1208 : The IMPLICIT is ICV_CAST when the user is explicitly converting an expression
1209 : to void via a cast. If an expression is being implicitly converted, IMPLICIT
1210 : indicates the context of the implicit conversion. */
1211 :
1212 : tree
1213 101678399 : convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
1214 : {
1215 108040094 : location_t loc = cp_expr_loc_or_input_loc (expr);
1216 :
1217 108040094 : if (expr == error_mark_node
1218 108040094 : || TREE_TYPE (expr) == error_mark_node)
1219 : return error_mark_node;
1220 :
1221 108035848 : expr = maybe_undo_parenthesized_ref (expr);
1222 :
1223 108035848 : if (invalid_nonstatic_memfn_p (loc, expr, complain))
1224 25 : return error_mark_node;
1225 108035823 : if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
1226 : {
1227 6 : if (complain & tf_error)
1228 6 : error_at (loc, "pseudo-destructor is not called");
1229 6 : return error_mark_node;
1230 : }
1231 :
1232 : /* Explicitly evaluate void-converted concept checks since their
1233 : satisfaction may produce ill-formed programs. */
1234 108035817 : if (concept_check_p (expr) && !cp_unevaluated_operand)
1235 25 : expr = evaluate_concept_check (expr);
1236 :
1237 : /* Detect using expressions of consteval-only types outside manifestly
1238 : constant-evaluated contexts. We are going to discard this expression,
1239 : so we can't wait till cp_fold_immediate_r. FIXME This is too early;
1240 : code like "int i = (^^i, 42);" is OK. We should stop discarding
1241 : expressions here (PR124249). */
1242 108035817 : if (stmts_are_full_exprs_p () && check_out_of_consteval_use (expr))
1243 28 : return error_mark_node;
1244 :
1245 108035789 : if (VOID_TYPE_P (TREE_TYPE (expr)))
1246 : return expr;
1247 :
1248 75304203 : expr = mark_discarded_use (expr);
1249 75304203 : if (implicit == ICV_CAST)
1250 : /* An explicit cast to void avoids all -Wunused-but-set* warnings. */
1251 1091622 : mark_exp_read (expr);
1252 :
1253 75304203 : switch (TREE_CODE (expr))
1254 : {
1255 133583 : case COND_EXPR:
1256 133583 : {
1257 : /* The two parts of a cond expr might be separate lvalues. */
1258 133583 : tree op1 = TREE_OPERAND (expr,1);
1259 133583 : tree op2 = TREE_OPERAND (expr,2);
1260 133577 : bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1))
1261 253196 : || TREE_SIDE_EFFECTS (op2));
1262 133583 : tree new_op1, new_op2;
1263 133583 : new_op1 = NULL_TREE;
1264 133583 : if (implicit != ICV_CAST && !side_effects)
1265 : {
1266 69 : if (op1)
1267 66 : new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
1268 69 : new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
1269 : }
1270 : else
1271 : {
1272 133514 : if (op1)
1273 133511 : new_op1 = convert_to_void (op1, ICV_CAST, complain);
1274 133514 : new_op2 = convert_to_void (op2, ICV_CAST, complain);
1275 : }
1276 :
1277 133583 : expr = build3_loc (loc, COND_EXPR, TREE_TYPE (new_op2),
1278 133583 : TREE_OPERAND (expr, 0), new_op1, new_op2);
1279 133583 : break;
1280 : }
1281 :
1282 503233 : case COMPOUND_EXPR:
1283 503233 : {
1284 : /* The second part of a compound expr contains the value. */
1285 503233 : tree op1 = TREE_OPERAND (expr,1);
1286 503233 : tree new_op1;
1287 503233 : if (implicit != ICV_CAST && !warning_suppressed_p (expr /* What warning? */))
1288 193211 : new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
1289 : else
1290 310022 : new_op1 = convert_to_void (op1, ICV_CAST, complain);
1291 :
1292 503233 : if (new_op1 != op1)
1293 : {
1294 503233 : tree t = build2_loc (loc, COMPOUND_EXPR, TREE_TYPE (new_op1),
1295 503233 : TREE_OPERAND (expr, 0), new_op1);
1296 503233 : expr = t;
1297 : }
1298 :
1299 : break;
1300 : }
1301 :
1302 : case NON_LVALUE_EXPR:
1303 : case NOP_EXPR:
1304 : /* These have already decayed to rvalue. */
1305 : break;
1306 :
1307 8162104 : case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
1308 : /* cdtors may return this or void, depending on
1309 : targetm.cxx.cdtor_returns_this, but this shouldn't affect our
1310 : decisions here: neither nodiscard warnings (nodiscard dtors
1311 : are nonsensical and ctors have a different behavior with that
1312 : attribute that is handled in the TARGET_EXPR case), nor should
1313 : any constexpr or template instantiations be affected by an ABI
1314 : property that is, or at least ought to be transparent to the
1315 : language. */
1316 8162104 : if (tree fn = cp_get_callee_fndecl_nofold (expr))
1317 15008186 : if (DECL_CONSTRUCTOR_P (fn) || DECL_DESTRUCTOR_P (fn))
1318 : return expr;
1319 :
1320 8162104 : if (complain & tf_warning)
1321 6120800 : maybe_warn_nodiscard (expr, implicit);
1322 : break;
1323 :
1324 7146410 : case INDIRECT_REF:
1325 7146410 : {
1326 7146410 : tree type = TREE_TYPE (expr);
1327 7146410 : int is_reference = TYPE_REF_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
1328 7146410 : int is_volatile = TYPE_VOLATILE (type);
1329 7146410 : if (is_volatile)
1330 433 : complete_type (type);
1331 7146410 : int is_complete = COMPLETE_TYPE_P (type);
1332 :
1333 : /* Don't load the value if this is an implicit dereference, or if
1334 : the type needs to be handled by ctors/dtors. */
1335 7146410 : if (is_reference)
1336 : {
1337 267 : if (is_volatile && (complain & tf_warning)
1338 : /* A co_await expression, in its await_resume expression, also
1339 : contains an implicit dereference. As a result, we don't
1340 : need to warn about them here. */
1341 6361776 : && TREE_CODE (TREE_OPERAND (expr, 0)) != CO_AWAIT_EXPR)
1342 72 : switch (implicit)
1343 : {
1344 36 : case ICV_CAST:
1345 36 : warning_at (loc, 0, "conversion to void will not access "
1346 : "object of type %qT", type);
1347 36 : break;
1348 0 : case ICV_SECOND_OF_COND:
1349 0 : warning_at (loc, 0, "implicit dereference will not access "
1350 : "object of type %qT in second operand of "
1351 : "conditional expression", type);
1352 0 : break;
1353 0 : case ICV_THIRD_OF_COND:
1354 0 : warning_at (loc, 0, "implicit dereference will not access "
1355 : "object of type %qT in third operand of "
1356 : "conditional expression", type);
1357 0 : break;
1358 0 : case ICV_RIGHT_OF_COMMA:
1359 0 : warning_at (loc, 0, "implicit dereference will not access "
1360 : "object of type %qT in right operand of "
1361 : "comma operator", type);
1362 0 : break;
1363 0 : case ICV_LEFT_OF_COMMA:
1364 0 : warning_at (loc, 0, "implicit dereference will not access "
1365 : "object of type %qT in left operand of comma "
1366 : "operator", type);
1367 0 : break;
1368 36 : case ICV_STATEMENT:
1369 36 : warning_at (loc, 0, "implicit dereference will not access "
1370 : "object of type %qT in statement", type);
1371 36 : break;
1372 0 : case ICV_THIRD_IN_FOR:
1373 0 : warning_at (loc, 0, "implicit dereference will not access "
1374 : "object of type %qT in for increment expression",
1375 : type);
1376 0 : break;
1377 0 : default:
1378 0 : gcc_unreachable ();
1379 : }
1380 :
1381 : /* Since this was an implicit dereference, we should also act as if
1382 : it was never there. */
1383 6361695 : return convert_to_void (TREE_OPERAND (expr, 0), implicit, complain);
1384 : }
1385 : /* Can't load the value if we don't know the type. */
1386 784715 : else if (is_volatile && !is_complete)
1387 : {
1388 18 : if (complain & tf_warning)
1389 18 : switch (implicit)
1390 : {
1391 12 : case ICV_CAST:
1392 12 : warning_at (loc, 0, "conversion to void will not access "
1393 : "object of incomplete type %qT", type);
1394 12 : break;
1395 0 : case ICV_SECOND_OF_COND:
1396 0 : warning_at (loc, 0, "indirection will not access object of "
1397 : "incomplete type %qT in second operand "
1398 : "of conditional expression", type);
1399 0 : break;
1400 0 : case ICV_THIRD_OF_COND:
1401 0 : warning_at (loc, 0, "indirection will not access object of "
1402 : "incomplete type %qT in third operand "
1403 : "of conditional expression", type);
1404 0 : break;
1405 0 : case ICV_RIGHT_OF_COMMA:
1406 0 : warning_at (loc, 0, "indirection will not access object of "
1407 : "incomplete type %qT in right operand of "
1408 : "comma operator", type);
1409 0 : break;
1410 0 : case ICV_LEFT_OF_COMMA:
1411 0 : warning_at (loc, 0, "indirection will not access object of "
1412 : "incomplete type %qT in left operand of "
1413 : "comma operator", type);
1414 0 : break;
1415 6 : case ICV_STATEMENT:
1416 6 : warning_at (loc, 0, "indirection will not access object of "
1417 : "incomplete type %qT in statement", type);
1418 6 : break;
1419 0 : case ICV_THIRD_IN_FOR:
1420 0 : warning_at (loc, 0, "indirection will not access object of "
1421 : "incomplete type %qT in for increment "
1422 : "expression", type);
1423 0 : break;
1424 0 : default:
1425 0 : gcc_unreachable ();
1426 : }
1427 : }
1428 784697 : else if (is_volatile && TREE_ADDRESSABLE (type))
1429 : {
1430 3 : if (complain & tf_warning)
1431 3 : switch (implicit)
1432 : {
1433 0 : case ICV_CAST:
1434 0 : warning_at (loc, 0, "conversion to void will not access "
1435 : "object of non-trivially-copyable type %qT",
1436 : type);
1437 0 : break;
1438 0 : case ICV_SECOND_OF_COND:
1439 0 : warning_at (loc, 0, "indirection will not access object of "
1440 : "non-trivially-copyable type %qT in second "
1441 : "operand of conditional expression", type);
1442 0 : break;
1443 0 : case ICV_THIRD_OF_COND:
1444 0 : warning_at (loc, 0, "indirection will not access object of "
1445 : "non-trivially-copyable type %qT in third "
1446 : "operand of conditional expression", type);
1447 0 : break;
1448 0 : case ICV_RIGHT_OF_COMMA:
1449 0 : warning_at (loc, 0, "indirection will not access object of "
1450 : "non-trivially-copyable type %qT in right "
1451 : "operand of comma operator", type);
1452 0 : break;
1453 0 : case ICV_LEFT_OF_COMMA:
1454 0 : warning_at (loc, 0, "indirection will not access object of "
1455 : "non-trivially-copyable type %qT in left "
1456 : "operand of comma operator", type);
1457 0 : break;
1458 3 : case ICV_STATEMENT:
1459 3 : warning_at (loc, 0, "indirection will not access object of "
1460 : "non-trivially-copyable type %qT in statement",
1461 : type);
1462 3 : break;
1463 0 : case ICV_THIRD_IN_FOR:
1464 0 : warning_at (loc, 0, "indirection will not access object of "
1465 : "non-trivially-copyable type %qT in for "
1466 : "increment expression", type);
1467 0 : break;
1468 0 : default:
1469 0 : gcc_unreachable ();
1470 : }
1471 : }
1472 784715 : if (!is_volatile || !is_complete || TREE_ADDRESSABLE (type))
1473 : {
1474 : /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
1475 : operation is stripped off. Note that we don't warn about
1476 : - an expression with TREE_NO_WARNING set. (For an example of
1477 : such expressions, see build_over_call in call.cc.)
1478 : - automatic dereferencing of references, since the user cannot
1479 : control it. (See also warn_if_unused_value() in c-common.cc.) */
1480 784570 : if (warn_unused_value
1481 3730 : && implicit != ICV_CAST
1482 2685 : && (complain & tf_warning)
1483 9 : && !warning_suppressed_p (expr, OPT_Wunused_value)
1484 784570 : && !is_reference)
1485 9 : warning_at (loc, OPT_Wunused_value, "value computed is not used");
1486 784570 : expr = TREE_OPERAND (expr, 0);
1487 : }
1488 :
1489 : break;
1490 : }
1491 :
1492 17894 : case VAR_DECL:
1493 17894 : {
1494 : /* External variables might be incomplete. */
1495 17894 : tree type = TREE_TYPE (expr);
1496 :
1497 17894 : if (TYPE_VOLATILE (type)
1498 138 : && !COMPLETE_TYPE_P (complete_type (type))
1499 17909 : && (complain & tf_warning))
1500 15 : switch (implicit)
1501 : {
1502 12 : case ICV_CAST:
1503 12 : warning_at (loc, 0, "conversion to void will not access "
1504 : "object %qE of incomplete type %qT", expr, type);
1505 12 : break;
1506 0 : case ICV_SECOND_OF_COND:
1507 0 : warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1508 : "not be accessed in second operand of "
1509 : "conditional expression", expr, type);
1510 0 : break;
1511 0 : case ICV_THIRD_OF_COND:
1512 0 : warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1513 : "not be accessed in third operand of "
1514 : "conditional expression", expr, type);
1515 0 : break;
1516 0 : case ICV_RIGHT_OF_COMMA:
1517 0 : warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1518 : "not be accessed in right operand of comma operator",
1519 : expr, type);
1520 0 : break;
1521 0 : case ICV_LEFT_OF_COMMA:
1522 0 : warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1523 : "not be accessed in left operand of comma operator",
1524 : expr, type);
1525 0 : break;
1526 3 : case ICV_STATEMENT:
1527 3 : warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1528 : "not be accessed in statement", expr, type);
1529 3 : break;
1530 0 : case ICV_THIRD_IN_FOR:
1531 0 : warning_at (loc, 0, "variable %qE of incomplete type %qT will "
1532 : "not be accessed in for increment expression",
1533 : expr, type);
1534 0 : break;
1535 0 : default:
1536 0 : gcc_unreachable ();
1537 : }
1538 :
1539 : break;
1540 : }
1541 :
1542 1652706 : case TARGET_EXPR:
1543 : /* Don't bother with the temporary object returned from a function if
1544 : we don't use it, don't need to destroy it, and won't abort in
1545 : assign_temp. We'll still
1546 : allocate space for it in expand_call or declare_return_variable,
1547 : but we don't need to track it through all the tree phases. */
1548 1652706 : if (TARGET_EXPR_IMPLICIT_P (expr)
1549 1652706 : && !TREE_ADDRESSABLE (TREE_TYPE (expr)))
1550 : {
1551 880156 : tree init = TARGET_EXPR_INITIAL (expr);
1552 880156 : if (TREE_CODE (init) == AGGR_INIT_EXPR
1553 880156 : && !AGGR_INIT_VIA_CTOR_P (init))
1554 : {
1555 0 : tree fn = AGGR_INIT_EXPR_FN (init);
1556 0 : expr = build_call_array_loc (input_location,
1557 0 : TREE_TYPE (TREE_TYPE
1558 : (TREE_TYPE (fn))),
1559 : fn,
1560 0 : aggr_init_expr_nargs (init),
1561 0 : AGGR_INIT_EXPR_ARGP (init));
1562 : }
1563 : }
1564 1652706 : if (complain & tf_warning)
1565 132378 : maybe_warn_nodiscard (expr, implicit);
1566 : break;
1567 :
1568 230 : case CO_AWAIT_EXPR:
1569 230 : if (auto awr = co_await_get_resume_call (expr))
1570 218 : convert_to_void (awr, implicit, complain);
1571 : break;
1572 :
1573 68942508 : default:;
1574 : }
1575 68942508 : expr = resolve_nondeduced_context (expr, complain);
1576 68942508 : if (!mark_single_function (expr, complain))
1577 9 : return error_mark_node;
1578 :
1579 68942499 : {
1580 68942499 : tree probe = expr;
1581 :
1582 68942499 : if (TREE_CODE (probe) == ADDR_EXPR)
1583 352 : probe = TREE_OPERAND (expr, 0);
1584 68942499 : if (type_unknown_p (probe))
1585 : {
1586 : /* [over.over] enumerates the places where we can take the address
1587 : of an overloaded function, and this is not one of them. */
1588 55 : if (complain & tf_error)
1589 36 : switch (implicit)
1590 : {
1591 12 : case ICV_CAST:
1592 12 : error_at (loc, "conversion to void "
1593 : "cannot resolve address of overloaded function");
1594 12 : break;
1595 0 : case ICV_SECOND_OF_COND:
1596 0 : error_at (loc, "second operand of conditional expression "
1597 : "cannot resolve address of overloaded function");
1598 0 : break;
1599 0 : case ICV_THIRD_OF_COND:
1600 0 : error_at (loc, "third operand of conditional expression "
1601 : "cannot resolve address of overloaded function");
1602 0 : break;
1603 0 : case ICV_RIGHT_OF_COMMA:
1604 0 : error_at (loc, "right operand of comma operator "
1605 : "cannot resolve address of overloaded function");
1606 0 : break;
1607 0 : case ICV_LEFT_OF_COMMA:
1608 0 : error_at (loc, "left operand of comma operator "
1609 : "cannot resolve address of overloaded function");
1610 0 : break;
1611 24 : case ICV_STATEMENT:
1612 24 : error_at (loc, "statement "
1613 : "cannot resolve address of overloaded function");
1614 24 : break;
1615 0 : case ICV_THIRD_IN_FOR:
1616 0 : error_at (loc, "for increment expression "
1617 : "cannot resolve address of overloaded function");
1618 0 : break;
1619 : }
1620 : else
1621 19 : return error_mark_node;
1622 36 : expr = void_node;
1623 : }
1624 68942444 : else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
1625 : {
1626 : /* Only warn when there is no &. */
1627 123 : if (complain & tf_warning)
1628 123 : switch (implicit)
1629 : {
1630 3 : case ICV_SECOND_OF_COND:
1631 3 : warning_at (loc, OPT_Waddress,
1632 : "second operand of conditional expression "
1633 : "is a reference, not call, to function %qE", expr);
1634 3 : break;
1635 3 : case ICV_THIRD_OF_COND:
1636 3 : warning_at (loc, OPT_Waddress,
1637 : "third operand of conditional expression "
1638 : "is a reference, not call, to function %qE", expr);
1639 3 : break;
1640 0 : case ICV_RIGHT_OF_COMMA:
1641 0 : warning_at (loc, OPT_Waddress,
1642 : "right operand of comma operator "
1643 : "is a reference, not call, to function %qE", expr);
1644 0 : break;
1645 11 : case ICV_LEFT_OF_COMMA:
1646 11 : warning_at (loc, OPT_Waddress,
1647 : "left operand of comma operator "
1648 : "is a reference, not call, to function %qE", expr);
1649 11 : break;
1650 106 : case ICV_STATEMENT:
1651 106 : warning_at (loc, OPT_Waddress,
1652 : "statement is a reference, not call, to function %qE",
1653 : expr);
1654 106 : break;
1655 0 : case ICV_THIRD_IN_FOR:
1656 0 : warning_at (loc, OPT_Waddress,
1657 : "for increment expression "
1658 : "is a reference, not call, to function %qE", expr);
1659 0 : break;
1660 0 : default:
1661 0 : gcc_unreachable ();
1662 : }
1663 :
1664 123 : if (TREE_CODE (expr) == COMPONENT_REF)
1665 9 : expr = TREE_OPERAND (expr, 0);
1666 : }
1667 : }
1668 :
1669 68942480 : if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
1670 : {
1671 68305628 : if (implicit != ICV_CAST
1672 67338215 : && warn_unused_value
1673 698061 : && !warning_suppressed_p (expr, OPT_Wunused_value)
1674 695416 : && !processing_template_decl
1675 561646 : && !cp_unevaluated_operand
1676 68809638 : && (complain & tf_warning))
1677 : {
1678 : /* The middle end does not warn about expressions that have
1679 : been explicitly cast to void, so we must do so here. */
1680 502646 : if (!TREE_SIDE_EFFECTS (expr))
1681 : {
1682 99 : switch (implicit)
1683 : {
1684 3 : case ICV_SECOND_OF_COND:
1685 3 : warning_at (loc, OPT_Wunused_value,
1686 : "second operand of conditional expression "
1687 : "has no effect");
1688 3 : break;
1689 3 : case ICV_THIRD_OF_COND:
1690 3 : warning_at (loc, OPT_Wunused_value,
1691 : "third operand of conditional expression "
1692 : "has no effect");
1693 3 : break;
1694 39 : case ICV_RIGHT_OF_COMMA:
1695 39 : warning_at (loc, OPT_Wunused_value,
1696 : "right operand of comma operator has no effect");
1697 39 : break;
1698 15 : case ICV_LEFT_OF_COMMA:
1699 15 : warning_at (loc, OPT_Wunused_value,
1700 : "left operand of comma operator has no effect");
1701 15 : break;
1702 39 : case ICV_STATEMENT:
1703 39 : warning_at (loc, OPT_Wunused_value,
1704 : "statement has no effect");
1705 36 : break;
1706 0 : case ICV_THIRD_IN_FOR:
1707 0 : warning_at (loc, OPT_Wunused_value,
1708 : "for increment expression has no effect");
1709 0 : break;
1710 0 : default:
1711 0 : gcc_unreachable ();
1712 : }
1713 : }
1714 : else
1715 : {
1716 : tree e = expr;
1717 : /* We might like to warn about (say) "(int) f()", as the
1718 : cast has no effect, but the compiler itself will
1719 : generate implicit conversions under some
1720 : circumstances. (For example a block copy will be
1721 : turned into a call to "__builtin_memcpy", with a
1722 : conversion of the return value to an appropriate
1723 : type.) So, to avoid false positives, we strip
1724 : conversions. Do not use STRIP_NOPs because it will
1725 : not strip conversions to "void", as that is not a
1726 : mode-preserving conversion. */
1727 502857 : while (TREE_CODE (e) == NOP_EXPR)
1728 310 : e = TREE_OPERAND (e, 0);
1729 :
1730 502547 : enum tree_code code = TREE_CODE (e);
1731 502547 : enum tree_code_class tclass = TREE_CODE_CLASS (code);
1732 502547 : if (tclass == tcc_comparison
1733 : || tclass == tcc_unary
1734 502547 : || tclass == tcc_binary
1735 502472 : || code == TRUTH_NOT_EXPR
1736 502472 : || code == ADDR_EXPR
1737 : || code == VEC_PERM_EXPR
1738 502464 : || code == VEC_COND_EXPR)
1739 89 : warn_if_unused_value (e, loc);
1740 : }
1741 : }
1742 68305625 : expr = build1 (CONVERT_EXPR, void_type_node, expr);
1743 : }
1744 68942477 : if (! TREE_SIDE_EFFECTS (expr))
1745 5056093 : expr = void_node;
1746 : return expr;
1747 : }
1748 :
1749 : /* Create an expression whose value is that of EXPR,
1750 : converted to type TYPE. The TREE_TYPE of the value
1751 : is always TYPE. This function implements all reasonable
1752 : conversions; callers should filter out those that are
1753 : not permitted by the language being compiled.
1754 :
1755 : Most of this routine is from build_reinterpret_cast.
1756 :
1757 : The back end cannot call cp_convert (what was convert) because
1758 : conversions to/from basetypes may involve memory references
1759 : (vbases) and adding or subtracting small values (multiple
1760 : inheritance), but it calls convert from the constant folding code
1761 : on subtrees of already built trees after it has ripped them apart.
1762 :
1763 : Also, if we ever support range variables, we'll probably also have to
1764 : do a little bit more work. */
1765 :
1766 : tree
1767 217299922 : convert (tree type, tree expr)
1768 : {
1769 217299922 : tree intype;
1770 :
1771 217299922 : if (type == error_mark_node || expr == error_mark_node)
1772 : return error_mark_node;
1773 :
1774 217297528 : intype = TREE_TYPE (expr);
1775 :
1776 217297528 : if (INDIRECT_TYPE_P (type) && INDIRECT_TYPE_P (intype))
1777 44975840 : return build_nop (type, expr);
1778 :
1779 172321688 : return ocp_convert (type, expr, CONV_BACKEND_CONVERT,
1780 : LOOKUP_NORMAL|LOOKUP_NO_CONVERSION,
1781 172321688 : tf_warning_or_error);
1782 : }
1783 :
1784 : /* Like convert, but in a static initializer (called from
1785 : convert_and_check). */
1786 :
1787 : tree
1788 0 : convert_init (tree type, tree expr)
1789 : {
1790 0 : return convert (type, expr);
1791 : }
1792 :
1793 : /* Like cp_convert, except permit conversions to take place which
1794 : are not normally allowed due to access restrictions
1795 : (such as conversion from sub-type to private super-type). */
1796 :
1797 : tree
1798 10008553 : convert_force (tree type, tree expr, int convtype, tsubst_flags_t complain)
1799 : {
1800 10008553 : tree e = expr;
1801 10008553 : enum tree_code code = TREE_CODE (type);
1802 :
1803 10008553 : if (code == REFERENCE_TYPE)
1804 0 : return convert_to_reference (type, e, CONV_C_CAST, 0,
1805 0 : NULL_TREE, complain);
1806 :
1807 10008553 : if (code == POINTER_TYPE)
1808 10008553 : return convert_to_pointer_force (type, e, complain);
1809 :
1810 : /* From typeck.cc convert_for_assignment */
1811 0 : if (((TYPE_PTR_P (TREE_TYPE (e)) && TREE_CODE (e) == ADDR_EXPR
1812 0 : && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE)
1813 0 : || integer_zerop (e)
1814 0 : || TYPE_PTRMEMFUNC_P (TREE_TYPE (e)))
1815 0 : && TYPE_PTRMEMFUNC_P (type))
1816 : /* compatible pointer to member functions. */
1817 0 : return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1,
1818 0 : /*c_cast_p=*/1, complain);
1819 :
1820 0 : return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL, complain);
1821 : }
1822 :
1823 : /* Convert an aggregate EXPR to type XTYPE. If a conversion
1824 : exists, return the attempted conversion. This may
1825 : return ERROR_MARK_NODE if the conversion is not
1826 : allowed (references private members, etc).
1827 : If no conversion exists, NULL_TREE is returned.
1828 :
1829 : FIXME: Ambiguity checking is wrong. Should choose one by the implicit
1830 : object parameter, or by the second standard conversion sequence if
1831 : that doesn't do it. This will probably wait for an overloading rewrite.
1832 : (jason 8/9/95) */
1833 :
1834 : static tree
1835 12 : build_type_conversion (tree xtype, tree expr)
1836 : {
1837 : /* C++: check to see if we can convert this aggregate type
1838 : into the required type. */
1839 12 : return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL,
1840 0 : tf_warning_or_error);
1841 : }
1842 :
1843 : /* Convert the given EXPR to one of a group of types suitable for use in an
1844 : expression. DESIRES is a combination of various WANT_* flags (q.v.)
1845 : which indicates which types are suitable. If COMPLAIN is true, complain
1846 : about ambiguity; otherwise, the caller will deal with it. */
1847 :
1848 : tree
1849 131580828 : build_expr_type_conversion (int desires, tree expr, bool complain)
1850 : {
1851 131580828 : tree basetype = TREE_TYPE (expr);
1852 131580828 : tree conv = NULL_TREE;
1853 131580828 : tree winner = NULL_TREE;
1854 :
1855 131580828 : if (null_node_p (expr)
1856 45 : && (desires & WANT_INT)
1857 131580864 : && !(desires & WANT_NULL))
1858 : {
1859 36 : location_t loc =
1860 36 : expansion_point_location_if_in_system_header (input_location);
1861 :
1862 36 : warning_at (loc, OPT_Wconversion_null,
1863 : "converting NULL to non-pointer type");
1864 : }
1865 :
1866 131580828 : if (basetype == error_mark_node)
1867 : return error_mark_node;
1868 :
1869 131580813 : if (! MAYBE_CLASS_TYPE_P (basetype))
1870 131580611 : switch (TREE_CODE (basetype))
1871 : {
1872 121433988 : case INTEGER_TYPE:
1873 121433988 : if ((desires & WANT_NULL) && null_ptr_cst_p (expr))
1874 : return expr;
1875 : /* fall through. */
1876 :
1877 121472706 : case BOOLEAN_TYPE:
1878 124712553 : return (desires & WANT_INT) ? expr : NULL_TREE;
1879 65768 : case ENUMERAL_TYPE:
1880 67551 : return (desires & WANT_ENUM) ? expr : NULL_TREE;
1881 1743095 : case REAL_TYPE:
1882 1743140 : return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1883 7124248 : case POINTER_TYPE:
1884 9226618 : return (desires & WANT_POINTER) ? expr : NULL_TREE;
1885 :
1886 1096135 : case FUNCTION_TYPE:
1887 1096135 : case ARRAY_TYPE:
1888 1096135 : return (desires & WANT_POINTER) ? decay_conversion (expr,
1889 : tf_warning_or_error)
1890 : : NULL_TREE;
1891 :
1892 63235 : case VECTOR_TYPE:
1893 63235 : if (!gnu_vector_type_p (basetype))
1894 : return NULL_TREE;
1895 : /* FALLTHROUGH */
1896 78595 : case COMPLEX_TYPE:
1897 78595 : if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1898 : return NULL_TREE;
1899 35199 : switch (TREE_CODE (TREE_TYPE (basetype)))
1900 : {
1901 770 : case INTEGER_TYPE:
1902 770 : case BOOLEAN_TYPE:
1903 770 : return (desires & WANT_INT) ? expr : NULL_TREE;
1904 0 : case ENUMERAL_TYPE:
1905 0 : return (desires & WANT_ENUM) ? expr : NULL_TREE;
1906 34429 : case REAL_TYPE:
1907 34435 : return (desires & WANT_FLOAT) ? expr : NULL_TREE;
1908 : default:
1909 : return NULL_TREE;
1910 : }
1911 :
1912 : default:
1913 : return NULL_TREE;
1914 : }
1915 :
1916 : /* The code for conversions from class type is currently only used for
1917 : delete expressions. Other expressions are handled by build_new_op. */
1918 202 : if (!complete_type_or_maybe_complain (basetype, expr, complain))
1919 0 : return error_mark_node;
1920 202 : if (!TYPE_HAS_CONVERSION (basetype))
1921 : return NULL_TREE;
1922 :
1923 407 : for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv))
1924 : {
1925 220 : int win = 0;
1926 220 : tree candidate;
1927 220 : tree cand = TREE_VALUE (conv);
1928 220 : cand = OVL_FIRST (cand);
1929 :
1930 220 : if (winner && winner == cand)
1931 0 : continue;
1932 :
1933 220 : if (DECL_NONCONVERTING_P (cand))
1934 3 : continue;
1935 :
1936 217 : candidate = non_reference (TREE_TYPE (TREE_TYPE (cand)));
1937 :
1938 217 : switch (TREE_CODE (candidate))
1939 : {
1940 160 : case BOOLEAN_TYPE:
1941 160 : case INTEGER_TYPE:
1942 160 : win = (desires & WANT_INT); break;
1943 15 : case ENUMERAL_TYPE:
1944 15 : win = (desires & WANT_ENUM); break;
1945 3 : case REAL_TYPE:
1946 3 : win = (desires & WANT_FLOAT); break;
1947 36 : case POINTER_TYPE:
1948 36 : win = (desires & WANT_POINTER); break;
1949 :
1950 0 : case COMPLEX_TYPE:
1951 0 : case VECTOR_TYPE:
1952 0 : if ((desires & WANT_VECTOR_OR_COMPLEX) == 0)
1953 : break;
1954 0 : switch (TREE_CODE (TREE_TYPE (candidate)))
1955 : {
1956 0 : case BOOLEAN_TYPE:
1957 0 : case INTEGER_TYPE:
1958 0 : win = (desires & WANT_INT); break;
1959 0 : case ENUMERAL_TYPE:
1960 0 : win = (desires & WANT_ENUM); break;
1961 0 : case REAL_TYPE:
1962 0 : win = (desires & WANT_FLOAT); break;
1963 : default:
1964 : break;
1965 : }
1966 : break;
1967 :
1968 3 : default:
1969 : /* A wildcard could be instantiated to match any desired
1970 : type, but we can't deduce the template argument. */
1971 3 : if (WILDCARD_TYPE_P (candidate))
1972 : win = true;
1973 : break;
1974 : }
1975 :
1976 214 : if (win)
1977 : {
1978 205 : if (TREE_CODE (cand) == TEMPLATE_DECL)
1979 : {
1980 6 : if (complain)
1981 6 : error ("default type conversion cannot deduce template"
1982 : " argument for %qD", cand);
1983 6 : return error_mark_node;
1984 : }
1985 :
1986 199 : if (winner)
1987 : {
1988 15 : tree winner_type
1989 15 : = non_reference (TREE_TYPE (TREE_TYPE (winner)));
1990 :
1991 15 : if (!same_type_ignoring_top_level_qualifiers_p (winner_type,
1992 : candidate))
1993 : {
1994 3 : if (complain)
1995 : {
1996 3 : auto_diagnostic_group d;
1997 3 : error ("ambiguous default type conversion from %qT",
1998 : basetype);
1999 3 : inform (input_location,
2000 : " candidate conversions include %qD and %qD",
2001 : winner, cand);
2002 3 : }
2003 3 : return error_mark_node;
2004 : }
2005 : }
2006 :
2007 : winner = cand;
2008 : }
2009 : }
2010 :
2011 187 : if (winner)
2012 : {
2013 181 : tree type = non_reference (TREE_TYPE (TREE_TYPE (winner)));
2014 181 : return build_user_type_conversion (type, expr, LOOKUP_NORMAL,
2015 181 : tf_warning_or_error);
2016 : }
2017 :
2018 : return NULL_TREE;
2019 : }
2020 :
2021 : /* Implements integral promotion (4.1) and float->double promotion. */
2022 :
2023 : tree
2024 436884976 : type_promotes_to (tree type)
2025 : {
2026 440501707 : tree promoted_type;
2027 :
2028 440501707 : if (type == error_mark_node)
2029 : return error_mark_node;
2030 :
2031 440501707 : type = TYPE_MAIN_VARIANT (type);
2032 :
2033 : /* Check for promotions of target-defined types first. */
2034 440501707 : promoted_type = targetm.promoted_type (type);
2035 440501707 : if (promoted_type)
2036 : return promoted_type;
2037 :
2038 : /* bool always promotes to int (not unsigned), even if it's the same
2039 : size. */
2040 440501707 : if (TREE_CODE (type) == BOOLEAN_TYPE)
2041 5489128 : type = integer_type_node;
2042 :
2043 : /* Normally convert enums to int, but convert wide enums to something
2044 : wider. Scoped enums don't promote, but pretend they do for backward
2045 : ABI bug compatibility wrt varargs. */
2046 435012579 : else if (TREE_CODE (type) == ENUMERAL_TYPE
2047 415869918 : || type == char8_type_node
2048 415541097 : || type == char16_type_node
2049 415269508 : || type == char32_type_node
2050 414547210 : || type == wchar_type_node)
2051 : {
2052 21589393 : tree prom = type;
2053 :
2054 21589393 : if (TREE_CODE (type) == ENUMERAL_TYPE)
2055 : {
2056 19142661 : prom = ENUM_UNDERLYING_TYPE (prom);
2057 19142661 : if (!ENUM_IS_SCOPED (type)
2058 19142661 : && ENUM_FIXED_UNDERLYING_TYPE_P (type))
2059 : {
2060 : /* ISO C++17, 7.6/4. A prvalue of an unscoped enumeration type
2061 : whose underlying type is fixed (10.2) can be converted to a
2062 : prvalue of its underlying type. Moreover, if integral promotion
2063 : can be applied to its underlying type, a prvalue of an unscoped
2064 : enumeration type whose underlying type is fixed can also be
2065 : converted to a prvalue of the promoted underlying type. */
2066 : return type_promotes_to (prom);
2067 : }
2068 : }
2069 :
2070 17972662 : int precision = MAX (TYPE_PRECISION (type),
2071 : TYPE_PRECISION (integer_type_node));
2072 17972662 : tree totype = c_common_type_for_size (precision, 0);
2073 17972662 : if (TYPE_UNSIGNED (prom)
2074 17972662 : && ! int_fits_type_p (TYPE_MAX_VALUE (prom), totype))
2075 907218 : prom = c_common_type_for_size (precision, 1);
2076 : else
2077 : prom = totype;
2078 17972662 : if (SCOPED_ENUM_P (type))
2079 : {
2080 63 : if (abi_version_crosses (6)
2081 33 : && TYPE_MODE (prom) != TYPE_MODE (type))
2082 60 : warning (OPT_Wabi, "scoped enum %qT passed through %<...%> as "
2083 : "%qT before %<-fabi-version=6%>, %qT after",
2084 30 : type, prom, ENUM_UNDERLYING_TYPE (type));
2085 33 : if (!abi_version_at_least (6))
2086 17972632 : type = prom;
2087 : }
2088 : else
2089 : type = prom;
2090 : }
2091 413423186 : else if (c_promoting_integer_type_p (type))
2092 : {
2093 : /* Retain unsignedness if really not getting bigger. */
2094 11203180 : if (TYPE_UNSIGNED (type)
2095 11203180 : && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node))
2096 0 : type = unsigned_type_node;
2097 : else
2098 11203180 : type = integer_type_node;
2099 : }
2100 402220006 : else if (type == float_type_node)
2101 10560898 : type = double_type_node;
2102 :
2103 : return type;
2104 : }
2105 :
2106 : /* The routines below this point are carefully written to conform to
2107 : the standard. They use the same terminology, and follow the rules
2108 : closely. Although they are used only in pt.cc at the moment, they
2109 : should presumably be used everywhere in the future. */
2110 :
2111 : /* True iff EXPR can be converted to TYPE via a qualification conversion.
2112 : Callers should check for identical types before calling this function. */
2113 :
2114 : bool
2115 57 : can_convert_qual (tree type, tree expr)
2116 : {
2117 57 : tree expr_type = TREE_TYPE (expr);
2118 57 : gcc_assert (!same_type_p (type, expr_type));
2119 :
2120 : /* A function pointer conversion also counts as a Qualification Adjustment
2121 : under [over.ics.scs]. */
2122 57 : if (fnptr_conv_p (type, expr_type))
2123 : return true;
2124 :
2125 47 : if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type))
2126 8 : return comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type));
2127 39 : else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (expr_type))
2128 38 : return (same_type_p (TYPE_PTRMEM_CLASS_TYPE (type),
2129 : TYPE_PTRMEM_CLASS_TYPE (expr_type))
2130 73 : && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type),
2131 35 : TYPE_PTRMEM_POINTED_TO_TYPE (expr_type)));
2132 : else
2133 : return false;
2134 : }
2135 :
2136 : /* Attempt to perform qualification conversions on EXPR to convert it
2137 : to TYPE. Return the resulting expression, or error_mark_node if
2138 : the conversion was impossible. Since this is only used by
2139 : convert_nontype_argument, we fold the conversion. */
2140 :
2141 : tree
2142 3818 : perform_qualification_conversions (tree type, tree expr)
2143 : {
2144 3818 : tree expr_type;
2145 :
2146 3818 : expr_type = TREE_TYPE (expr);
2147 :
2148 3818 : if (same_type_p (type, expr_type))
2149 : return expr;
2150 21 : else if (can_convert_qual (type, expr))
2151 14 : return cp_fold_convert (type, expr);
2152 : else
2153 7 : return error_mark_node;
2154 : }
2155 :
2156 : /* True iff T is a transaction-safe function type. */
2157 :
2158 : bool
2159 8301612 : tx_safe_fn_type_p (tree t)
2160 : {
2161 8301612 : if (!FUNC_OR_METHOD_TYPE_P (t))
2162 : return false;
2163 8295387 : return !!lookup_attribute ("transaction_safe", TYPE_ATTRIBUTES (t));
2164 : }
2165 :
2166 : /* Return the transaction-unsafe variant of transaction-safe function type
2167 : T. */
2168 :
2169 : tree
2170 444 : tx_unsafe_fn_variant (tree t)
2171 : {
2172 444 : gcc_assert (tx_safe_fn_type_p (t));
2173 444 : tree attrs = remove_attribute ("transaction_safe",
2174 444 : TYPE_ATTRIBUTES (t));
2175 444 : return cp_build_type_attribute_variant (t, attrs);
2176 : }
2177 :
2178 : /* Return true iff FROM can convert to TO by a transaction-safety
2179 : conversion. */
2180 :
2181 : static bool
2182 153526010 : can_convert_tx_safety (tree to, tree from)
2183 : {
2184 5761 : return (flag_tm && tx_safe_fn_type_p (from)
2185 153526452 : && same_type_p (to, tx_unsafe_fn_variant (from)));
2186 : }
2187 :
2188 : /* Return true iff FROM can convert to TO by dropping noexcept.
2189 : This is just a subroutine of fnptr_conv_p. */
2190 :
2191 : static bool
2192 154427825 : noexcept_conv_p (tree to, tree from)
2193 : {
2194 154427825 : if (!flag_noexcept_type)
2195 : return false;
2196 :
2197 154050621 : if (TREE_CODE (to) != TREE_CODE (from))
2198 : return false;
2199 90574888 : if (!FUNC_OR_METHOD_TYPE_P (from))
2200 : return false;
2201 4977092 : if (!type_throw_all_p (to)
2202 4977092 : || type_throw_all_p (from))
2203 92078 : return false;
2204 4885014 : tree v = build_exception_variant (from, NULL_TREE);
2205 4885014 : return same_type_p (to, v);
2206 : }
2207 :
2208 : /* Return true iff FROM can convert to TO by a function pointer conversion. */
2209 :
2210 : bool
2211 154427825 : fnptr_conv_p (tree to, tree from)
2212 : {
2213 154427825 : tree t = to;
2214 154427825 : tree f = from;
2215 1871 : if (TYPE_PTRMEMFUNC_P (t)
2216 154429696 : && TYPE_PTRMEMFUNC_P (f))
2217 : {
2218 1800 : t = TYPE_PTRMEMFUNC_FN_TYPE (t);
2219 1800 : f = TYPE_PTRMEMFUNC_FN_TYPE (f);
2220 : }
2221 154427825 : if (INDIRECT_TYPE_P (t)
2222 149688978 : && INDIRECT_TYPE_P (f))
2223 : {
2224 149688931 : t = TREE_TYPE (t);
2225 149688931 : f = TREE_TYPE (f);
2226 : }
2227 :
2228 154427825 : return (noexcept_conv_p (t, f)
2229 154427825 : || can_convert_tx_safety (t, f));
2230 : }
2231 :
2232 : /* Return FN with any NOP_EXPRs stripped that represent function pointer
2233 : conversions or conversions to the same type. */
2234 :
2235 : tree
2236 1783 : strip_fnptr_conv (tree fn)
2237 : {
2238 1802 : while (TREE_CODE (fn) == NOP_EXPR)
2239 : {
2240 41 : tree op = TREE_OPERAND (fn, 0);
2241 41 : tree ft = TREE_TYPE (fn);
2242 41 : tree ot = TREE_TYPE (op);
2243 82 : if (same_type_p (ft, ot)
2244 41 : || fnptr_conv_p (ft, ot))
2245 : fn = op;
2246 : else
2247 : break;
2248 : }
2249 1783 : return fn;
2250 : }
|
