* gensupport.c (old_preds): Don't reference PREDICATE_CODES.
[official-gcc.git] / gcc / cp / cp-gimplify.c
blob5397cc8818fb39e7b6be6f7fa274a14335387378
1 /* C++-specific tree lowering bits; see also c-gimplify.c and tree-gimple.c.
3 Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 Contributed by Jason Merrill <jason@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
21 02110-1301, USA. */
23 #include "config.h"
24 #include "system.h"
25 #include "coretypes.h"
26 #include "tm.h"
27 #include "tree.h"
28 #include "cp-tree.h"
29 #include "c-common.h"
30 #include "toplev.h"
31 #include "tree-gimple.h"
32 #include "hashtab.h"
33 #include "pointer-set.h"
34 #include "flags.h"
36 /* Local declarations. */
38 enum bc_t { bc_break = 0, bc_continue = 1 };
40 static struct cp_gimplify_ctx
42 /* Stack of labels which are targets for "break" or "continue",
43 linked through TREE_CHAIN. */
44 tree current_label[2];
45 } *ctxp;
47 static void
48 push_context (void)
50 gcc_assert (!ctxp);
51 ctxp = ((struct cp_gimplify_ctx *)
52 xcalloc (1, sizeof (struct cp_gimplify_ctx)));
55 static void
56 pop_context (void)
58 gcc_assert (ctxp
59 && !ctxp->current_label[0]
60 && !ctxp->current_label[1]);
61 free (ctxp);
62 ctxp = NULL;
65 /* Begin a scope which can be exited by a break or continue statement. BC
66 indicates which.
68 Just creates a label and pushes it into the current context. */
70 static tree
71 begin_bc_block (enum bc_t bc)
73 tree label = create_artificial_label ();
74 TREE_CHAIN (label) = ctxp->current_label[bc];
75 ctxp->current_label[bc] = label;
76 return label;
79 /* Finish a scope which can be exited by a break or continue statement.
80 LABEL was returned from the most recent call to begin_bc_block. BODY is
81 an expression for the contents of the scope.
83 If we saw a break (or continue) in the scope, append a LABEL_EXPR to
84 body. Otherwise, just forget the label. */
86 static tree
87 finish_bc_block (enum bc_t bc, tree label, tree body)
89 gcc_assert (label == ctxp->current_label[bc]);
91 if (TREE_USED (label))
93 tree t, sl = NULL;
95 t = build1 (LABEL_EXPR, void_type_node, label);
97 append_to_statement_list (body, &sl);
98 append_to_statement_list (t, &sl);
99 body = sl;
102 ctxp->current_label[bc] = TREE_CHAIN (label);
103 TREE_CHAIN (label) = NULL_TREE;
104 return body;
107 /* Build a GOTO_EXPR to represent a break or continue statement. BC
108 indicates which. */
110 static tree
111 build_bc_goto (enum bc_t bc)
113 tree label = ctxp->current_label[bc];
115 if (label == NULL_TREE)
117 if (bc == bc_break)
118 error ("break statement not within loop or switch");
119 else
120 error ("continue statement not within loop or switch");
122 return NULL_TREE;
125 /* Mark the label used for finish_bc_block. */
126 TREE_USED (label) = 1;
127 return build1 (GOTO_EXPR, void_type_node, label);
130 /* Genericize a TRY_BLOCK. */
132 static void
133 genericize_try_block (tree *stmt_p)
135 tree body = TRY_STMTS (*stmt_p);
136 tree cleanup = TRY_HANDLERS (*stmt_p);
138 gimplify_stmt (&body);
140 if (CLEANUP_P (*stmt_p))
141 /* A cleanup is an expression, so it doesn't need to be genericized. */;
142 else
143 gimplify_stmt (&cleanup);
145 *stmt_p = build2 (TRY_CATCH_EXPR, void_type_node, body, cleanup);
148 /* Genericize a HANDLER by converting to a CATCH_EXPR. */
150 static void
151 genericize_catch_block (tree *stmt_p)
153 tree type = HANDLER_TYPE (*stmt_p);
154 tree body = HANDLER_BODY (*stmt_p);
156 gimplify_stmt (&body);
158 /* FIXME should the caught type go in TREE_TYPE? */
159 *stmt_p = build2 (CATCH_EXPR, void_type_node, type, body);
162 /* Genericize an EH_SPEC_BLOCK by converting it to a
163 TRY_CATCH_EXPR/EH_FILTER_EXPR pair. */
165 static void
166 genericize_eh_spec_block (tree *stmt_p)
168 tree body = EH_SPEC_STMTS (*stmt_p);
169 tree allowed = EH_SPEC_RAISES (*stmt_p);
170 tree failure = build_call (call_unexpected_node,
171 tree_cons (NULL_TREE, build_exc_ptr (),
172 NULL_TREE));
173 gimplify_stmt (&body);
175 *stmt_p = gimple_build_eh_filter (body, allowed, failure);
178 /* Genericize an IF_STMT by turning it into a COND_EXPR. */
180 static void
181 gimplify_if_stmt (tree *stmt_p)
183 tree stmt, cond, then_, else_;
185 stmt = *stmt_p;
186 cond = IF_COND (stmt);
187 then_ = THEN_CLAUSE (stmt);
188 else_ = ELSE_CLAUSE (stmt);
190 if (!then_)
191 then_ = build_empty_stmt ();
192 if (!else_)
193 else_ = build_empty_stmt ();
195 if (integer_nonzerop (cond) && !TREE_SIDE_EFFECTS (else_))
196 stmt = then_;
197 else if (integer_zerop (cond) && !TREE_SIDE_EFFECTS (then_))
198 stmt = else_;
199 else
200 stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_);
201 *stmt_p = stmt;
204 /* Build a generic representation of one of the C loop forms. COND is the
205 loop condition or NULL_TREE. BODY is the (possibly compound) statement
206 controlled by the loop. INCR is the increment expression of a for-loop,
207 or NULL_TREE. COND_IS_FIRST indicates whether the condition is
208 evaluated before the loop body as in while and for loops, or after the
209 loop body as in do-while loops. */
211 static tree
212 gimplify_cp_loop (tree cond, tree body, tree incr, bool cond_is_first)
214 tree top, entry, exit, cont_block, break_block, stmt_list, t;
215 location_t stmt_locus;
217 stmt_locus = input_location;
218 stmt_list = NULL_TREE;
219 entry = NULL_TREE;
221 break_block = begin_bc_block (bc_break);
222 cont_block = begin_bc_block (bc_continue);
224 /* If condition is zero don't generate a loop construct. */
225 if (cond && integer_zerop (cond))
227 top = NULL_TREE;
228 exit = NULL_TREE;
229 if (cond_is_first)
231 t = build_bc_goto (bc_break);
232 append_to_statement_list (t, &stmt_list);
235 else
237 /* If we use a LOOP_EXPR here, we have to feed the whole thing
238 back through the main gimplifier to lower it. Given that we
239 have to gimplify the loop body NOW so that we can resolve
240 break/continue stmts, seems easier to just expand to gotos. */
241 top = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
243 /* If we have an exit condition, then we build an IF with gotos either
244 out of the loop, or to the top of it. If there's no exit condition,
245 then we just build a jump back to the top. */
246 exit = build_and_jump (&LABEL_EXPR_LABEL (top));
247 if (cond && !integer_nonzerop (cond))
249 t = build_bc_goto (bc_break);
250 exit = build3 (COND_EXPR, void_type_node, cond, exit, t);
251 exit = fold (exit);
252 gimplify_stmt (&exit);
254 if (cond_is_first)
256 if (incr)
258 entry = build1 (LABEL_EXPR, void_type_node, NULL_TREE);
259 t = build_and_jump (&LABEL_EXPR_LABEL (entry));
261 else
262 t = build_bc_goto (bc_continue);
263 append_to_statement_list (t, &stmt_list);
268 gimplify_stmt (&body);
269 gimplify_stmt (&incr);
271 body = finish_bc_block (bc_continue, cont_block, body);
273 append_to_statement_list (top, &stmt_list);
274 append_to_statement_list (body, &stmt_list);
275 append_to_statement_list (incr, &stmt_list);
276 append_to_statement_list (entry, &stmt_list);
277 append_to_statement_list (exit, &stmt_list);
279 annotate_all_with_locus (&stmt_list, stmt_locus);
281 return finish_bc_block (bc_break, break_block, stmt_list);
284 /* Gimplify a FOR_STMT node. Move the stuff in the for-init-stmt into the
285 prequeue and hand off to gimplify_cp_loop. */
287 static void
288 gimplify_for_stmt (tree *stmt_p, tree *pre_p)
290 tree stmt = *stmt_p;
292 if (FOR_INIT_STMT (stmt))
293 gimplify_and_add (FOR_INIT_STMT (stmt), pre_p);
295 *stmt_p = gimplify_cp_loop (FOR_COND (stmt), FOR_BODY (stmt),
296 FOR_EXPR (stmt), 1);
299 /* Gimplify a WHILE_STMT node. */
301 static void
302 gimplify_while_stmt (tree *stmt_p)
304 tree stmt = *stmt_p;
305 *stmt_p = gimplify_cp_loop (WHILE_COND (stmt), WHILE_BODY (stmt),
306 NULL_TREE, 1);
309 /* Gimplify a DO_STMT node. */
311 static void
312 gimplify_do_stmt (tree *stmt_p)
314 tree stmt = *stmt_p;
315 *stmt_p = gimplify_cp_loop (DO_COND (stmt), DO_BODY (stmt),
316 NULL_TREE, 0);
319 /* Genericize a SWITCH_STMT by turning it into a SWITCH_EXPR. */
321 static void
322 gimplify_switch_stmt (tree *stmt_p)
324 tree stmt = *stmt_p;
325 tree break_block, body;
326 location_t stmt_locus = input_location;
328 break_block = begin_bc_block (bc_break);
330 body = SWITCH_STMT_BODY (stmt);
331 if (!body)
332 body = build_empty_stmt ();
334 *stmt_p = build3 (SWITCH_EXPR, SWITCH_STMT_TYPE (stmt),
335 SWITCH_STMT_COND (stmt), body, NULL_TREE);
336 SET_EXPR_LOCATION (*stmt_p, stmt_locus);
337 gimplify_stmt (stmt_p);
339 *stmt_p = finish_bc_block (bc_break, break_block, *stmt_p);
342 /* Gimplify an EXPR_STMT node. */
344 static void
345 gimplify_expr_stmt (tree *stmt_p)
347 tree stmt = EXPR_STMT_EXPR (*stmt_p);
349 if (stmt == error_mark_node)
350 stmt = NULL;
352 /* Gimplification of a statement expression will nullify the
353 statement if all its side effects are moved to *PRE_P and *POST_P.
355 In this case we will not want to emit the gimplified statement.
356 However, we may still want to emit a warning, so we do that before
357 gimplification. */
358 if (stmt && (extra_warnings || warn_unused_value))
360 if (!TREE_SIDE_EFFECTS (stmt))
362 if (!IS_EMPTY_STMT (stmt)
363 && !VOID_TYPE_P (TREE_TYPE (stmt))
364 && !TREE_NO_WARNING (stmt))
365 warning (0, "statement with no effect");
367 else if (warn_unused_value)
368 warn_if_unused_value (stmt, input_location);
371 if (stmt == NULL_TREE)
372 stmt = alloc_stmt_list ();
374 *stmt_p = stmt;
377 /* Gimplify initialization from an AGGR_INIT_EXPR. */
379 static void
380 cp_gimplify_init_expr (tree *expr_p, tree *pre_p, tree *post_p)
382 tree from = TREE_OPERAND (*expr_p, 1);
383 tree to = TREE_OPERAND (*expr_p, 0);
384 tree sub;
386 /* If we are initializing something from a TARGET_EXPR, strip the
387 TARGET_EXPR and initialize it directly. */
388 /* What about code that pulls out the temp and uses it elsewhere? I
389 think that such code never uses the TARGET_EXPR as an initializer. If
390 I'm wrong, we'll abort because the temp won't have any RTL. In that
391 case, I guess we'll need to replace references somehow. */
392 if (TREE_CODE (from) == TARGET_EXPR)
393 from = TARGET_EXPR_INITIAL (from);
394 if (TREE_CODE (from) == CLEANUP_POINT_EXPR)
395 from = TREE_OPERAND (from, 0);
397 /* Look through any COMPOUND_EXPRs. */
398 sub = expr_last (from);
400 /* If we are initializing from an AGGR_INIT_EXPR, drop the INIT_EXPR and
401 replace the slot operand with our target.
403 Should we add a target parm to gimplify_expr instead? No, as in this
404 case we want to replace the INIT_EXPR. */
405 if (TREE_CODE (sub) == AGGR_INIT_EXPR)
407 gimplify_expr (&to, pre_p, post_p, is_gimple_lvalue, fb_lvalue);
408 TREE_OPERAND (sub, 2) = to;
409 *expr_p = from;
411 /* The initialization is now a side-effect, so the container can
412 become void. */
413 if (from != sub)
414 TREE_TYPE (from) = void_type_node;
418 /* Gimplify a MUST_NOT_THROW_EXPR. */
420 static void
421 gimplify_must_not_throw_expr (tree *expr_p, tree *pre_p)
423 tree stmt = *expr_p;
424 tree temp = voidify_wrapper_expr (stmt, NULL);
425 tree body = TREE_OPERAND (stmt, 0);
427 gimplify_stmt (&body);
429 stmt = gimple_build_eh_filter (body, NULL_TREE,
430 build_call (terminate_node, NULL_TREE));
432 if (temp)
434 append_to_statement_list (stmt, pre_p);
435 *expr_p = temp;
437 else
438 *expr_p = stmt;
441 /* Do C++-specific gimplification. Args are as for gimplify_expr. */
444 cp_gimplify_expr (tree *expr_p, tree *pre_p, tree *post_p)
446 int saved_stmts_are_full_exprs_p = 0;
447 enum tree_code code = TREE_CODE (*expr_p);
448 enum gimplify_status ret;
450 if (STATEMENT_CODE_P (code))
452 saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
453 current_stmt_tree ()->stmts_are_full_exprs_p
454 = STMT_IS_FULL_EXPR_P (*expr_p);
457 switch (code)
459 case PTRMEM_CST:
460 *expr_p = cplus_expand_constant (*expr_p);
461 ret = GS_OK;
462 break;
464 case AGGR_INIT_EXPR:
465 simplify_aggr_init_expr (expr_p);
466 ret = GS_OK;
467 break;
469 case THROW_EXPR:
470 /* FIXME communicate throw type to backend, probably by moving
471 THROW_EXPR into ../tree.def. */
472 *expr_p = TREE_OPERAND (*expr_p, 0);
473 ret = GS_OK;
474 break;
476 case MUST_NOT_THROW_EXPR:
477 gimplify_must_not_throw_expr (expr_p, pre_p);
478 ret = GS_OK;
479 break;
481 case INIT_EXPR:
482 case MODIFY_EXPR:
483 cp_gimplify_init_expr (expr_p, pre_p, post_p);
484 ret = GS_OK;
485 break;
487 case EMPTY_CLASS_EXPR:
488 /* We create an INTEGER_CST with RECORD_TYPE and value zero. */
489 *expr_p = build_int_cst (TREE_TYPE (*expr_p), 0);
490 ret = GS_OK;
491 break;
493 case BASELINK:
494 *expr_p = BASELINK_FUNCTIONS (*expr_p);
495 ret = GS_OK;
496 break;
498 case TRY_BLOCK:
499 genericize_try_block (expr_p);
500 ret = GS_OK;
501 break;
503 case HANDLER:
504 genericize_catch_block (expr_p);
505 ret = GS_OK;
506 break;
508 case EH_SPEC_BLOCK:
509 genericize_eh_spec_block (expr_p);
510 ret = GS_OK;
511 break;
513 case USING_STMT:
514 /* Just ignore for now. Eventually we will want to pass this on to
515 the debugger. */
516 *expr_p = build_empty_stmt ();
517 ret = GS_ALL_DONE;
518 break;
520 case IF_STMT:
521 gimplify_if_stmt (expr_p);
522 ret = GS_OK;
523 break;
525 case FOR_STMT:
526 gimplify_for_stmt (expr_p, pre_p);
527 ret = GS_ALL_DONE;
528 break;
530 case WHILE_STMT:
531 gimplify_while_stmt (expr_p);
532 ret = GS_ALL_DONE;
533 break;
535 case DO_STMT:
536 gimplify_do_stmt (expr_p);
537 ret = GS_ALL_DONE;
538 break;
540 case SWITCH_STMT:
541 gimplify_switch_stmt (expr_p);
542 ret = GS_ALL_DONE;
543 break;
545 case CONTINUE_STMT:
546 *expr_p = build_bc_goto (bc_continue);
547 ret = GS_ALL_DONE;
548 break;
550 case BREAK_STMT:
551 *expr_p = build_bc_goto (bc_break);
552 ret = GS_ALL_DONE;
553 break;
555 case EXPR_STMT:
556 gimplify_expr_stmt (expr_p);
557 ret = GS_OK;
558 break;
560 case UNARY_PLUS_EXPR:
562 tree arg = TREE_OPERAND (*expr_p, 0);
563 tree type = TREE_TYPE (*expr_p);
564 *expr_p = (TREE_TYPE (arg) != type) ? fold_convert (type, arg)
565 : arg;
566 ret = GS_OK;
568 break;
570 default:
571 ret = c_gimplify_expr (expr_p, pre_p, post_p);
572 break;
575 /* Restore saved state. */
576 if (STATEMENT_CODE_P (code))
577 current_stmt_tree ()->stmts_are_full_exprs_p
578 = saved_stmts_are_full_exprs_p;
580 return ret;
583 static inline bool
584 is_invisiref_parm (tree t)
586 return ((TREE_CODE (t) == PARM_DECL || TREE_CODE (t) == RESULT_DECL)
587 && DECL_BY_REFERENCE (t));
590 /* Perform any pre-gimplification lowering of C++ front end trees to
591 GENERIC. */
593 static tree
594 cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
596 tree stmt = *stmt_p;
597 struct pointer_set_t *p_set = (struct pointer_set_t*) data;
599 if (is_invisiref_parm (stmt))
601 *stmt_p = convert_from_reference (stmt);
602 *walk_subtrees = 0;
603 return NULL;
606 /* Other than invisiref parms, don't walk the same tree twice. */
607 if (pointer_set_contains (p_set, stmt))
609 *walk_subtrees = 0;
610 return NULL_TREE;
613 if (TREE_CODE (stmt) == ADDR_EXPR
614 && is_invisiref_parm (TREE_OPERAND (stmt, 0)))
616 *stmt_p = convert (TREE_TYPE (stmt), TREE_OPERAND (stmt, 0));
617 *walk_subtrees = 0;
619 else if (TREE_CODE (stmt) == RETURN_EXPR
620 && TREE_OPERAND (stmt, 0)
621 && is_invisiref_parm (TREE_OPERAND (stmt, 0)))
622 /* Don't dereference an invisiref RESULT_DECL inside a RETURN_EXPR. */
623 *walk_subtrees = 0;
624 else if (IS_TYPE_OR_DECL_P (stmt))
625 *walk_subtrees = 0;
627 /* Due to the way voidify_wrapper_expr is written, we don't get a chance
628 to lower this construct before scanning it, so we need to lower these
629 before doing anything else. */
630 else if (TREE_CODE (stmt) == CLEANUP_STMT)
631 *stmt_p = build2 (CLEANUP_EH_ONLY (stmt) ? TRY_CATCH_EXPR
632 : TRY_FINALLY_EXPR,
633 void_type_node,
634 CLEANUP_BODY (stmt),
635 CLEANUP_EXPR (stmt));
637 pointer_set_insert (p_set, *stmt_p);
639 return NULL;
642 void
643 cp_genericize (tree fndecl)
645 tree t;
646 struct pointer_set_t *p_set;
648 /* Fix up the types of parms passed by invisible reference. */
649 for (t = DECL_ARGUMENTS (fndecl); t; t = TREE_CHAIN (t))
650 if (TREE_ADDRESSABLE (TREE_TYPE (t)))
652 /* If a function's arguments are copied to create a thunk,
653 then DECL_BY_REFERENCE will be set -- but the type of the
654 argument will be a pointer type, so we will never get
655 here. */
656 gcc_assert (!DECL_BY_REFERENCE (t));
657 gcc_assert (DECL_ARG_TYPE (t) != TREE_TYPE (t));
658 TREE_TYPE (t) = DECL_ARG_TYPE (t);
659 DECL_BY_REFERENCE (t) = 1;
660 TREE_ADDRESSABLE (t) = 0;
661 relayout_decl (t);
664 /* Do the same for the return value. */
665 if (TREE_ADDRESSABLE (TREE_TYPE (DECL_RESULT (fndecl))))
667 t = DECL_RESULT (fndecl);
668 TREE_TYPE (t) = build_reference_type (TREE_TYPE (t));
669 DECL_BY_REFERENCE (t) = 1;
670 TREE_ADDRESSABLE (t) = 0;
671 relayout_decl (t);
674 /* If we're a clone, the body is already GIMPLE. */
675 if (DECL_CLONED_FUNCTION_P (fndecl))
676 return;
678 /* We do want to see every occurrence of the parms, so we can't just use
679 walk_tree's hash functionality. */
680 p_set = pointer_set_create ();
681 walk_tree (&DECL_SAVED_TREE (fndecl), cp_genericize_r, p_set, NULL);
682 pointer_set_destroy (p_set);
684 /* Do everything else. */
685 push_context ();
686 c_genericize (fndecl);
687 pop_context ();