Line data Source code
1 : /* Convert language-specific tree expression to rtl instructions,
2 : for GNU compiler.
3 : Copyright (C) 1988-2026 Free Software Foundation, Inc.
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 : #include "config.h"
23 : #include "system.h"
24 : #include "coretypes.h"
25 : #include "cp-tree.h"
26 :
27 : /* Expand C++-specific constants. Currently, this means PTRMEM_CST. */
28 :
29 : tree
30 95919353 : cplus_expand_constant (tree cst)
31 : {
32 95919353 : switch (TREE_CODE (cst))
33 : {
34 34564 : case PTRMEM_CST:
35 34564 : {
36 34564 : tree type = TREE_TYPE (cst);
37 34564 : tree member;
38 :
39 : /* Find the member. */
40 34564 : member = PTRMEM_CST_MEMBER (cst);
41 :
42 : /* We can't lower this until the class is complete. */
43 34564 : if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
44 : return cst;
45 :
46 34531 : if (TREE_CODE (member) == FIELD_DECL)
47 : {
48 : /* Find the offset for the field. */
49 2915 : cst = byte_position (member);
50 5963 : while (!same_type_p (DECL_CONTEXT (member),
51 : TYPE_PTRMEM_CLASS_TYPE (type)))
52 : {
53 : /* The MEMBER must have been nestled within an
54 : anonymous aggregate contained in TYPE. Find the
55 : anonymous aggregate. */
56 133 : member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
57 133 : DECL_CONTEXT (member));
58 133 : cst = size_binop (PLUS_EXPR, cst, byte_position (member));
59 : }
60 2915 : cst = fold (build_nop (type, cst));
61 : }
62 : else
63 : {
64 31616 : tree delta;
65 31616 : tree pfn;
66 :
67 31616 : expand_ptrmemfunc_cst (cst, &delta, &pfn);
68 31616 : cst = build_ptrmemfunc1 (type, delta, pfn);
69 : }
70 : }
71 : break;
72 :
73 : case CONSTRUCTOR:
74 : {
75 : constructor_elt *elt;
76 : unsigned HOST_WIDE_INT idx;
77 71003682 : FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
78 65882364 : elt->value = cplus_expand_constant (elt->value);
79 : }
80 :
81 : default:
82 : /* There's nothing to do. */
83 : break;
84 : }
85 :
86 : return cst;
87 : }
88 :
89 : /* We've seen an actual use of EXPR. Possibly replace an outer variable
90 : reference inside with its constant value or a lambda capture. */
91 :
92 : tree
93 6682626054 : mark_use (tree expr, bool rvalue_p, bool read_p,
94 : location_t loc /* = UNKNOWN_LOCATION */,
95 : bool reject_builtin /* = true */)
96 : {
97 : #define RECUR(t) mark_use ((t), rvalue_p, read_p, loc, reject_builtin)
98 :
99 6682626054 : if (expr == NULL_TREE || error_operand_p (expr))
100 : return expr;
101 :
102 6682621053 : if (reject_builtin && reject_gcc_builtin (expr, loc))
103 67 : return error_mark_node;
104 :
105 6682620986 : if (TREE_TYPE (expr) && VOID_TYPE_P (TREE_TYPE (expr)))
106 : read_p = false;
107 :
108 6566565491 : if (read_p)
109 6497293408 : mark_exp_read (expr);
110 :
111 6682620986 : tree oexpr = expr;
112 6682620986 : bool recurse_op[3] = { false, false, false };
113 6682620986 : switch (TREE_CODE (expr))
114 : {
115 1695991715 : case VAR_DECL:
116 1695991715 : case PARM_DECL:
117 1695991715 : if (rvalue_p && is_normal_capture_proxy (expr))
118 : {
119 : /* Look through capture by copy. */
120 6488799 : tree cap = DECL_CAPTURED_VARIABLE (expr);
121 6488799 : if (TREE_CODE (TREE_TYPE (cap)) == TREE_CODE (TREE_TYPE (expr))
122 6488799 : && decl_constant_var_p (cap))
123 : {
124 184 : tree val = RECUR (cap);
125 184 : if (!is_capture_proxy (val))
126 : {
127 145 : tree l = current_lambda_expr ();
128 145 : LAMBDA_EXPR_CAPTURE_OPTIMIZED (l) = true;
129 : }
130 184 : return val;
131 : }
132 : }
133 1695991531 : if (outer_automatic_var_p (expr)
134 1695991531 : && decl_constant_var_p (expr))
135 : {
136 86864 : if (rvalue_p)
137 : {
138 86855 : tree t = maybe_constant_value (expr);
139 86855 : if (TREE_CONSTANT (t))
140 : {
141 : expr = t;
142 6140066652 : break;
143 : }
144 : }
145 69 : iloc_sentinel l (loc);
146 69 : expr = process_outer_var_ref (expr, tf_warning_or_error, true);
147 69 : if (!(TREE_TYPE (oexpr)
148 69 : && TYPE_REF_P (TREE_TYPE (oexpr))))
149 51 : expr = convert_from_reference (expr);
150 69 : }
151 : break;
152 150365566 : case COMPONENT_REF:
153 150365566 : recurse_op[0] = true;
154 150365566 : break;
155 14047642 : case COMPOUND_EXPR:
156 14047642 : recurse_op[1] = true;
157 14047642 : break;
158 18084351 : case COND_EXPR:
159 18084351 : recurse_op[2] = true;
160 18084351 : if (TREE_OPERAND (expr, 1))
161 18084312 : recurse_op[1] = true;
162 : break;
163 360417546 : case INDIRECT_REF:
164 360417546 : if (REFERENCE_REF_P (expr))
165 : {
166 : /* Try to look through the reference. */
167 201420061 : tree ref = TREE_OPERAND (expr, 0);
168 201420061 : if (rvalue_p && is_normal_capture_proxy (ref))
169 : {
170 : /* Look through capture by reference. */
171 709214 : tree cap = DECL_CAPTURED_VARIABLE (ref);
172 709214 : if (!TYPE_REF_P (TREE_TYPE (cap))
173 709214 : && decl_constant_var_p (cap))
174 : {
175 1733 : tree val = RECUR (cap);
176 1733 : if (!is_capture_proxy (val))
177 : {
178 1733 : tree l = current_lambda_expr ();
179 1733 : LAMBDA_EXPR_CAPTURE_OPTIMIZED (l) = true;
180 : }
181 1733 : return val;
182 : }
183 : }
184 201418328 : tree r = mark_rvalue_use (ref, loc, reject_builtin);
185 201418328 : if (r != ref)
186 : {
187 21 : if (!rvalue_p)
188 : {
189 : /* Make sure we still return an lvalue. */
190 12 : gcc_assert (TREE_CODE (r) == NOP_EXPR);
191 12 : TREE_TYPE (r) = cp_build_reference_type (TREE_TYPE (r),
192 : false);
193 : }
194 21 : expr = convert_from_reference (r);
195 : }
196 : }
197 : break;
198 :
199 552096761 : case VIEW_CONVERT_EXPR:
200 552096761 : if (location_wrapper_p (expr))
201 : {
202 542552417 : loc = EXPR_LOCATION (expr);
203 542552417 : tree op = TREE_OPERAND (expr, 0);
204 542552417 : tree nop = RECUR (op);
205 542552417 : if (nop == error_mark_node)
206 : return error_mark_node;
207 542552405 : else if (op == nop)
208 : /* No change. */;
209 610 : else if (DECL_P (nop) || CONSTANT_CLASS_P (nop))
210 : {
211 : /* Reuse the location wrapper. */
212 581 : TREE_OPERAND (expr, 0) = nop;
213 : /* If we're replacing a DECL with a constant, we also need to
214 : change the TREE_CODE of the location wrapper. */
215 581 : if (rvalue_p)
216 581 : TREE_SET_CODE (expr, NON_LVALUE_EXPR);
217 : }
218 : else
219 : {
220 : /* Drop the location wrapper. */
221 29 : expr = nop;
222 29 : protected_set_expr_location (expr, loc);
223 : }
224 542552405 : return expr;
225 : }
226 810290747 : gcc_fallthrough ();
227 810290747 : CASE_CONVERT:
228 810290747 : recurse_op[0] = true;
229 810290747 : break;
230 :
231 2984889 : case MODIFY_EXPR:
232 2984889 : {
233 2984889 : tree lhs = TREE_OPERAND (expr, 0);
234 : /* [expr.ass] "An assignment whose left operand is of
235 : a volatile-qualified type is deprecated unless the assignment
236 : is either a discarded-value expression or appears in an
237 : unevaluated context." */
238 2984889 : if (!cp_unevaluated_operand
239 2984763 : && (TREE_THIS_VOLATILE (lhs)
240 2983796 : || CP_TYPE_VOLATILE_P (TREE_TYPE (lhs)))
241 2985856 : && !TREE_THIS_VOLATILE (expr))
242 : {
243 581 : if (warning_at (location_of (expr), OPT_Wvolatile,
244 : "using value of assignment with "
245 : "%<volatile%>-qualified left operand is "
246 : "deprecated"))
247 : /* Make sure not to warn about this assignment again. */
248 90 : TREE_THIS_VOLATILE (expr) = true;
249 : }
250 : break;
251 : }
252 :
253 : default:
254 : break;
255 : }
256 :
257 24560266590 : for (int i = 0; i < 3; ++i)
258 18420199944 : if (recurse_op[i])
259 : {
260 1010872618 : tree op = TREE_OPERAND (expr, i);
261 1010872618 : op = RECUR (op);
262 1010872618 : if (op == error_mark_node)
263 : return error_mark_node;
264 1010872612 : TREE_OPERAND (expr, i) = op;
265 : }
266 :
267 : return expr;
268 : #undef RECUR
269 : }
270 :
271 : /* Called whenever the expression EXPR is used in an rvalue context.
272 : When REJECT_BUILTIN is true the expression is checked to make sure
273 : it doesn't make it possible to obtain the address of a GCC built-in
274 : function with no library fallback (or any of its bits, such as in
275 : a conversion to bool). */
276 :
277 : tree
278 3953256758 : mark_rvalue_use (tree e,
279 : location_t loc /* = UNKNOWN_LOCATION */,
280 : bool reject_builtin /* = true */)
281 : {
282 3953256758 : return mark_use (e, true, true, loc, reject_builtin);
283 : }
284 :
285 : /* Called whenever an expression is used in an lvalue context. */
286 :
287 : tree
288 399120885 : mark_lvalue_use (tree expr)
289 : {
290 399120885 : return mark_use (expr, false, true, input_location, false);
291 : }
292 :
293 : /* As above, but don't consider this use a read. */
294 :
295 : tree
296 37146551 : mark_lvalue_use_nonread (tree expr)
297 : {
298 37146551 : return mark_use (expr, false, false, input_location, false);
299 : }
300 :
301 : /* Called when expr appears as a discarded-value expression. */
302 :
303 : tree
304 73520516 : mark_discarded_use (tree expr)
305 : {
306 : /* The lvalue-to-rvalue conversion (7.1) is applied if and only if the
307 : expression is a glvalue of volatile-qualified type and it is one of the
308 : following:
309 : * ( expression ), where expression is one of these expressions,
310 : * id-expression (8.1.4),
311 : * subscripting (8.2.1),
312 : * class member access (8.2.5),
313 : * indirection (8.3.1),
314 : * pointer-to-member operation (8.5),
315 : * conditional expression (8.16) where both the second and the third
316 : operands are one of these expressions, or
317 : * comma expression (8.19) where the right operand is one of these
318 : expressions. */
319 73520516 : if (expr == NULL_TREE)
320 : return expr;
321 :
322 73520510 : STRIP_ANY_LOCATION_WRAPPER (expr);
323 :
324 73520510 : switch (TREE_CODE (expr))
325 : {
326 121682 : case COND_EXPR:
327 121682 : TREE_OPERAND (expr, 2) = mark_discarded_use (TREE_OPERAND (expr, 2));
328 591399 : gcc_fallthrough ();
329 591399 : case COMPOUND_EXPR:
330 591399 : TREE_OPERAND (expr, 1) = mark_discarded_use (TREE_OPERAND (expr, 1));
331 591399 : return expr;
332 :
333 : case COMPONENT_REF:
334 : case ARRAY_REF:
335 : case INDIRECT_REF:
336 : case MEMBER_REF:
337 : break;
338 65484948 : default:
339 65484948 : if (DECL_P (expr))
340 : break;
341 : else
342 : return expr;
343 : }
344 :
345 : /* Like mark_rvalue_use, but don't reject built-ins. */
346 7472492 : return mark_use (expr, true, true, input_location, false);
347 : }
348 :
349 : /* Called whenever an expression is used in a type use context. */
350 :
351 : tree
352 115364340 : mark_type_use (tree expr)
353 : {
354 115364340 : mark_exp_read (expr);
355 115364340 : return expr;
356 : }
357 :
358 : /* Mark EXP as read, not just set, for set but not used -Wunused
359 : warning purposes. */
360 :
361 : void
362 7036939719 : mark_exp_read (tree exp)
363 : {
364 10600222148 : if (exp == NULL)
365 : return;
366 :
367 10595871998 : if (TREE_TYPE (exp) && VOID_TYPE_P (TREE_TYPE (exp)))
368 : return;
369 :
370 10464901127 : switch (TREE_CODE (exp))
371 : {
372 1186760688 : case VAR_DECL:
373 1186760688 : if (DECL_DECOMPOSITION_P (exp))
374 7520937 : mark_exp_read (DECL_DECOMP_BASE (exp));
375 3490100548 : gcc_fallthrough ();
376 3490100548 : case PARM_DECL:
377 3490100548 : DECL_READ_P (exp) = 1;
378 3490100548 : break;
379 3515528643 : CASE_CONVERT:
380 3515528643 : case ARRAY_REF:
381 3515528643 : case COMPONENT_REF:
382 3515528643 : case MODIFY_EXPR:
383 3515528643 : case REALPART_EXPR:
384 3515528643 : case IMAGPART_EXPR:
385 3515528643 : case ADDR_EXPR:
386 3515528643 : case INDIRECT_REF:
387 3515528643 : case FLOAT_EXPR:
388 3515528643 : case VIEW_CONVERT_EXPR:
389 3515528643 : case PREINCREMENT_EXPR:
390 3515528643 : case PREDECREMENT_EXPR:
391 3515528643 : case POSTINCREMENT_EXPR:
392 3515528643 : case POSTDECREMENT_EXPR:
393 3515528643 : mark_exp_read (TREE_OPERAND (exp, 0));
394 3515528643 : break;
395 22822972 : case COMPOUND_EXPR:
396 22822972 : mark_exp_read (TREE_OPERAND (exp, 1));
397 22822972 : break;
398 24930814 : case COND_EXPR:
399 24930814 : if (TREE_OPERAND (exp, 1))
400 24930765 : mark_exp_read (TREE_OPERAND (exp, 1));
401 24930814 : if (TREE_OPERAND (exp, 2))
402 24930814 : mark_exp_read (TREE_OPERAND (exp, 2));
403 : break;
404 : default:
405 : break;
406 : }
407 : }
408 :
409 : /* Fold X for consideration by one of the warning functions when checking
410 : whether an expression has a constant value. */
411 :
412 : tree
413 76937964 : fold_for_warn (tree x)
414 : {
415 : /* C++ implementation. */
416 :
417 76937964 : if (cp_unevaluated_operand)
418 : /* In an unevaluated context we don't care about the reduced value
419 : of an expression, so neither should any warnings. */
420 : return x;
421 :
422 : /* Prevent warning-dependent constexpr evaluation from changing
423 : DECL_UID (which breaks -fcompare-debug) and from instantiating
424 : templates. */
425 76885441 : uid_sensitive_constexpr_evaluation_sentinel s;
426 :
427 : /* It's not generally safe to fully fold inside of a template, so
428 : call fold_non_dependent_expr instead. */
429 76885441 : if (processing_template_decl)
430 : {
431 3808101 : tree f = fold_non_dependent_expr (x, tf_none);
432 3808101 : if (f == error_mark_node)
433 : return x;
434 : else
435 3808099 : return f;
436 : }
437 73077340 : else if (cxx_dialect >= cxx11)
438 72590717 : x = maybe_constant_value (x);
439 :
440 73077340 : return c_fully_fold (x, /*for_init*/false, /*maybe_constp*/NULL);
441 76885441 : }
442 :
443 : /* Make EXPR only execute during constant evaluation by wrapping it in a
444 : statement-expression containing 'if consteval'. */
445 :
446 : tree
447 1 : wrap_with_if_consteval (tree expr)
448 : {
449 1 : tree stmtex = begin_stmt_expr ();
450 1 : tree ifcev = begin_if_stmt ();
451 1 : IF_STMT_CONSTEVAL_P (ifcev) = true;
452 1 : finish_if_stmt_cond (boolean_false_node, ifcev);
453 1 : finish_expr_stmt (expr);
454 1 : finish_then_clause (ifcev);
455 1 : finish_if_stmt (ifcev);
456 1 : return finish_stmt_expr (stmtex, /*no scope*/true);
457 : }
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