1 /* GIMPLE lowering pass. Converts High GIMPLE into Low GIMPLE.
3 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
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 3, or (at your option) any later
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
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
28 #include "tree-iterator.h"
29 #include "tree-inline.h"
30 #include "tree-flow.h"
33 #include "diagnostic-core.h"
34 #include "tree-pass.h"
35 #include "langhooks.h"
37 /* The differences between High GIMPLE and Low GIMPLE are the
40 1- Lexical scopes are removed (i.e., GIMPLE_BIND disappears).
42 2- GIMPLE_TRY and GIMPLE_CATCH are converted to abnormal control
43 flow and exception regions are built as an on-the-side region
44 hierarchy (See tree-eh.c:lower_eh_constructs).
46 3- Multiple identical return statements are grouped into a single
47 return and gotos to the unique return site. */
49 /* Match a return statement with a label. During lowering, we identify
50 identical return statements and replace duplicates with a jump to
51 the corresponding label. */
52 struct return_statements_t
57 typedef struct return_statements_t return_statements_t;
59 DEF_VEC_O(return_statements_t);
60 DEF_VEC_ALLOC_O(return_statements_t,heap);
64 /* Block the current statement belongs to. */
67 /* A vector of label and return statements to be moved to the end
69 VEC(return_statements_t,heap) *return_statements;
71 /* True if the current statement cannot fall through. */
74 /* True if the function calls __builtin_setjmp. */
75 bool calls_builtin_setjmp;
78 static void lower_stmt (gimple_stmt_iterator *, struct lower_data *);
79 static void lower_gimple_bind (gimple_stmt_iterator *, struct lower_data *);
80 static void lower_gimple_return (gimple_stmt_iterator *, struct lower_data *);
81 static void lower_builtin_setjmp (gimple_stmt_iterator *);
84 /* Lower the body of current_function_decl from High GIMPLE into Low
88 lower_function_body (void)
90 struct lower_data data;
91 gimple_seq body = gimple_body (current_function_decl);
92 gimple_seq lowered_body;
93 gimple_stmt_iterator i;
98 /* The gimplifier should've left a body of exactly one statement,
99 namely a GIMPLE_BIND. */
100 gcc_assert (gimple_seq_first (body) == gimple_seq_last (body)
101 && gimple_code (gimple_seq_first_stmt (body)) == GIMPLE_BIND);
103 memset (&data, 0, sizeof (data));
104 data.block = DECL_INITIAL (current_function_decl);
105 BLOCK_SUBBLOCKS (data.block) = NULL_TREE;
106 BLOCK_CHAIN (data.block) = NULL_TREE;
107 TREE_ASM_WRITTEN (data.block) = 1;
108 data.return_statements = VEC_alloc (return_statements_t, heap, 8);
110 bind = gimple_seq_first_stmt (body);
112 gimple_seq_add_stmt (&lowered_body, bind);
113 i = gsi_start (lowered_body);
114 lower_gimple_bind (&i, &data);
116 /* Once the old body has been lowered, replace it with the new
118 gimple_set_body (current_function_decl, lowered_body);
120 i = gsi_last (lowered_body);
122 /* If the function falls off the end, we need a null return statement.
123 If we've already got one in the return_statements vector, we don't
124 need to do anything special. Otherwise build one by hand. */
125 if (gimple_seq_may_fallthru (lowered_body)
126 && (VEC_empty (return_statements_t, data.return_statements)
127 || gimple_return_retval (VEC_last (return_statements_t,
128 data.return_statements)->stmt) != NULL))
130 x = gimple_build_return (NULL);
131 gimple_set_location (x, cfun->function_end_locus);
132 gimple_set_block (x, DECL_INITIAL (current_function_decl));
133 gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
136 /* If we lowered any return statements, emit the representative
137 at the end of the function. */
138 while (!VEC_empty (return_statements_t, data.return_statements))
140 return_statements_t t;
142 /* Unfortunately, we can't use VEC_pop because it returns void for
144 t = *VEC_last (return_statements_t, data.return_statements);
145 VEC_truncate (return_statements_t,
146 data.return_statements,
147 VEC_length (return_statements_t,
148 data.return_statements) - 1);
150 x = gimple_build_label (t.label);
151 gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
152 gsi_insert_after (&i, t.stmt, GSI_CONTINUE_LINKING);
155 /* If the function calls __builtin_setjmp, we need to emit the computed
156 goto that will serve as the unique dispatcher for all the receivers. */
157 if (data.calls_builtin_setjmp)
159 tree disp_label, disp_var, arg;
161 /* Build 'DISP_LABEL:' and insert. */
162 disp_label = create_artificial_label (cfun->function_end_locus);
163 /* This mark will create forward edges from every call site. */
164 DECL_NONLOCAL (disp_label) = 1;
165 cfun->has_nonlocal_label = 1;
166 x = gimple_build_label (disp_label);
167 gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
169 /* Build 'DISP_VAR = __builtin_setjmp_dispatcher (DISP_LABEL);'
171 disp_var = create_tmp_var (ptr_type_node, "setjmpvar");
172 arg = build_addr (disp_label, current_function_decl);
173 t = builtin_decl_implicit (BUILT_IN_SETJMP_DISPATCHER);
174 x = gimple_build_call (t, 1, arg);
175 gimple_call_set_lhs (x, disp_var);
177 /* Build 'goto DISP_VAR;' and insert. */
178 gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
179 x = gimple_build_goto (disp_var);
180 gsi_insert_after (&i, x, GSI_CONTINUE_LINKING);
183 gcc_assert (data.block == DECL_INITIAL (current_function_decl));
184 BLOCK_SUBBLOCKS (data.block)
185 = blocks_nreverse (BLOCK_SUBBLOCKS (data.block));
187 clear_block_marks (data.block);
188 VEC_free(return_statements_t, heap, data.return_statements);
192 struct gimple_opt_pass pass_lower_cf =
198 lower_function_body, /* execute */
201 0, /* static_pass_number */
203 PROP_gimple_any, /* properties_required */
204 PROP_gimple_lcf, /* properties_provided */
205 0, /* properties_destroyed */
206 0, /* todo_flags_start */
207 0 /* todo_flags_finish */
213 /* Verify if the type of the argument matches that of the function
214 declaration. If we cannot verify this or there is a mismatch,
218 gimple_check_call_args (gimple stmt, tree fndecl)
221 unsigned int i, nargs;
223 /* Calls to internal functions always match their signature. */
224 if (gimple_call_internal_p (stmt))
227 nargs = gimple_call_num_args (stmt);
229 /* Get argument types for verification. */
231 parms = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
233 parms = TYPE_ARG_TYPES (gimple_call_fntype (stmt));
235 /* Verify if the type of the argument matches that of the function
236 declaration. If we cannot verify this or there is a mismatch,
238 if (fndecl && DECL_ARGUMENTS (fndecl))
240 for (i = 0, p = DECL_ARGUMENTS (fndecl);
242 i++, p = DECL_CHAIN (p))
244 /* We cannot distinguish a varargs function from the case
245 of excess parameters, still deferring the inlining decision
246 to the callee is possible. */
249 if (p == error_mark_node
250 || gimple_call_arg (stmt, i) == error_mark_node
251 || !fold_convertible_p (DECL_ARG_TYPE (p),
252 gimple_call_arg (stmt, i)))
258 for (i = 0, p = parms; i < nargs; i++, p = TREE_CHAIN (p))
260 /* If this is a varargs function defer inlining decision
264 if (TREE_VALUE (p) == error_mark_node
265 || gimple_call_arg (stmt, i) == error_mark_node
266 || TREE_CODE (TREE_VALUE (p)) == VOID_TYPE
267 || !fold_convertible_p (TREE_VALUE (p),
268 gimple_call_arg (stmt, i)))
280 /* Verify if the type of the argument and lhs of CALL_STMT matches
281 that of the function declaration CALLEE.
282 If we cannot verify this or there is a mismatch, return false. */
285 gimple_check_call_matching_types (gimple call_stmt, tree callee)
289 if ((DECL_RESULT (callee)
290 && !DECL_BY_REFERENCE (DECL_RESULT (callee))
291 && (lhs = gimple_call_lhs (call_stmt)) != NULL_TREE
292 && !useless_type_conversion_p (TREE_TYPE (DECL_RESULT (callee)),
294 && !fold_convertible_p (TREE_TYPE (DECL_RESULT (callee)), lhs))
295 || !gimple_check_call_args (call_stmt, callee))
300 /* Lower sequence SEQ. Unlike gimplification the statements are not relowered
301 when they are changed -- if this has to be done, the lowering routine must
302 do it explicitly. DATA is passed through the recursion. */
305 lower_sequence (gimple_seq seq, struct lower_data *data)
307 gimple_stmt_iterator gsi;
309 for (gsi = gsi_start (seq); !gsi_end_p (gsi); )
310 lower_stmt (&gsi, data);
314 /* Lower the OpenMP directive statement pointed by GSI. DATA is
315 passed through the recursion. */
318 lower_omp_directive (gimple_stmt_iterator *gsi, struct lower_data *data)
322 stmt = gsi_stmt (*gsi);
324 lower_sequence (gimple_omp_body (stmt), data);
325 gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
326 gsi_insert_seq_before (gsi, gimple_omp_body (stmt), GSI_SAME_STMT);
327 gimple_omp_set_body (stmt, NULL);
328 gsi_remove (gsi, false);
332 /* Lower statement GSI. DATA is passed through the recursion. We try to
333 track the fallthruness of statements and get rid of unreachable return
334 statements in order to prevent the EH lowering pass from adding useless
335 edges that can cause bogus warnings to be issued later; this guess need
336 not be 100% accurate, simply be conservative and reset cannot_fallthru
337 to false if we don't know. */
340 lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data)
342 gimple stmt = gsi_stmt (*gsi);
344 gimple_set_block (stmt, data->block);
346 switch (gimple_code (stmt))
349 lower_gimple_bind (gsi, data);
350 /* Propagate fallthruness. */
356 data->cannot_fallthru = true;
361 if (data->cannot_fallthru)
363 gsi_remove (gsi, false);
364 /* Propagate fallthruness. */
368 lower_gimple_return (gsi, data);
369 data->cannot_fallthru = true;
375 bool try_cannot_fallthru;
376 lower_sequence (gimple_try_eval (stmt), data);
377 try_cannot_fallthru = data->cannot_fallthru;
378 data->cannot_fallthru = false;
379 lower_sequence (gimple_try_cleanup (stmt), data);
380 /* See gimple_stmt_may_fallthru for the rationale. */
381 if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
383 data->cannot_fallthru |= try_cannot_fallthru;
391 data->cannot_fallthru = false;
392 lower_sequence (gimple_catch_handler (stmt), data);
395 case GIMPLE_EH_FILTER:
396 data->cannot_fallthru = false;
397 lower_sequence (gimple_eh_filter_failure (stmt), data);
401 lower_sequence (gimple_eh_else_n_body (stmt), data);
402 lower_sequence (gimple_eh_else_e_body (stmt), data);
410 case GIMPLE_EH_MUST_NOT_THROW:
412 case GIMPLE_OMP_SECTIONS:
413 case GIMPLE_OMP_SECTIONS_SWITCH:
414 case GIMPLE_OMP_SECTION:
415 case GIMPLE_OMP_SINGLE:
416 case GIMPLE_OMP_MASTER:
417 case GIMPLE_OMP_ORDERED:
418 case GIMPLE_OMP_CRITICAL:
419 case GIMPLE_OMP_RETURN:
420 case GIMPLE_OMP_ATOMIC_LOAD:
421 case GIMPLE_OMP_ATOMIC_STORE:
422 case GIMPLE_OMP_CONTINUE:
427 tree decl = gimple_call_fndecl (stmt);
430 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
431 && DECL_FUNCTION_CODE (decl) == BUILT_IN_SETJMP)
433 lower_builtin_setjmp (gsi);
434 data->cannot_fallthru = false;
435 data->calls_builtin_setjmp = true;
439 if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN))
441 data->cannot_fallthru = true;
448 case GIMPLE_OMP_PARALLEL:
449 case GIMPLE_OMP_TASK:
450 data->cannot_fallthru = false;
451 lower_omp_directive (gsi, data);
452 data->cannot_fallthru = false;
455 case GIMPLE_TRANSACTION:
456 lower_sequence (gimple_transaction_body (stmt), data);
463 data->cannot_fallthru = false;
467 /* Lower a bind_expr TSI. DATA is passed through the recursion. */
470 lower_gimple_bind (gimple_stmt_iterator *gsi, struct lower_data *data)
472 tree old_block = data->block;
473 gimple stmt = gsi_stmt (*gsi);
474 tree new_block = gimple_bind_block (stmt);
478 if (new_block == old_block)
480 /* The outermost block of the original function may not be the
481 outermost statement chain of the gimplified function. So we
482 may see the outermost block just inside the function. */
483 gcc_assert (new_block == DECL_INITIAL (current_function_decl));
488 /* We do not expect to handle duplicate blocks. */
489 gcc_assert (!TREE_ASM_WRITTEN (new_block));
490 TREE_ASM_WRITTEN (new_block) = 1;
492 /* Block tree may get clobbered by inlining. Normally this would
493 be fixed in rest_of_decl_compilation using block notes, but
494 since we are not going to emit them, it is up to us. */
495 BLOCK_CHAIN (new_block) = BLOCK_SUBBLOCKS (old_block);
496 BLOCK_SUBBLOCKS (old_block) = new_block;
497 BLOCK_SUBBLOCKS (new_block) = NULL_TREE;
498 BLOCK_SUPERCONTEXT (new_block) = old_block;
500 data->block = new_block;
504 record_vars (gimple_bind_vars (stmt));
505 lower_sequence (gimple_bind_body (stmt), data);
509 gcc_assert (data->block == new_block);
511 BLOCK_SUBBLOCKS (new_block)
512 = blocks_nreverse (BLOCK_SUBBLOCKS (new_block));
513 data->block = old_block;
516 /* The GIMPLE_BIND no longer carries any useful information -- kill it. */
517 gsi_insert_seq_before (gsi, gimple_bind_body (stmt), GSI_SAME_STMT);
518 gsi_remove (gsi, false);
521 /* Try to determine whether a TRY_CATCH expression can fall through.
522 This is a subroutine of block_may_fallthru. */
525 try_catch_may_fallthru (const_tree stmt)
527 tree_stmt_iterator i;
529 /* If the TRY block can fall through, the whole TRY_CATCH can
531 if (block_may_fallthru (TREE_OPERAND (stmt, 0)))
534 i = tsi_start (TREE_OPERAND (stmt, 1));
535 switch (TREE_CODE (tsi_stmt (i)))
538 /* We expect to see a sequence of CATCH_EXPR trees, each with a
539 catch expression and a body. The whole TRY_CATCH may fall
540 through iff any of the catch bodies falls through. */
541 for (; !tsi_end_p (i); tsi_next (&i))
543 if (block_may_fallthru (CATCH_BODY (tsi_stmt (i))))
549 /* The exception filter expression only matters if there is an
550 exception. If the exception does not match EH_FILTER_TYPES,
551 we will execute EH_FILTER_FAILURE, and we will fall through
552 if that falls through. If the exception does match
553 EH_FILTER_TYPES, the stack unwinder will continue up the
554 stack, so we will not fall through. We don't know whether we
555 will throw an exception which matches EH_FILTER_TYPES or not,
556 so we just ignore EH_FILTER_TYPES and assume that we might
557 throw an exception which doesn't match. */
558 return block_may_fallthru (EH_FILTER_FAILURE (tsi_stmt (i)));
561 /* This case represents statements to be executed when an
562 exception occurs. Those statements are implicitly followed
563 by a RESX statement to resume execution after the exception.
564 So in this case the TRY_CATCH never falls through. */
570 /* Same as above, but for a GIMPLE_TRY_CATCH. */
573 gimple_try_catch_may_fallthru (gimple stmt)
575 gimple_stmt_iterator i;
577 /* We don't handle GIMPLE_TRY_FINALLY. */
578 gcc_assert (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH);
580 /* If the TRY block can fall through, the whole TRY_CATCH can
582 if (gimple_seq_may_fallthru (gimple_try_eval (stmt)))
585 i = gsi_start (gimple_try_cleanup (stmt));
586 switch (gimple_code (gsi_stmt (i)))
589 /* We expect to see a sequence of GIMPLE_CATCH stmts, each with a
590 catch expression and a body. The whole try/catch may fall
591 through iff any of the catch bodies falls through. */
592 for (; !gsi_end_p (i); gsi_next (&i))
594 if (gimple_seq_may_fallthru (gimple_catch_handler (gsi_stmt (i))))
599 case GIMPLE_EH_FILTER:
600 /* The exception filter expression only matters if there is an
601 exception. If the exception does not match EH_FILTER_TYPES,
602 we will execute EH_FILTER_FAILURE, and we will fall through
603 if that falls through. If the exception does match
604 EH_FILTER_TYPES, the stack unwinder will continue up the
605 stack, so we will not fall through. We don't know whether we
606 will throw an exception which matches EH_FILTER_TYPES or not,
607 so we just ignore EH_FILTER_TYPES and assume that we might
608 throw an exception which doesn't match. */
609 return gimple_seq_may_fallthru (gimple_eh_filter_failure (gsi_stmt (i)));
612 /* This case represents statements to be executed when an
613 exception occurs. Those statements are implicitly followed
614 by a GIMPLE_RESX to resume execution after the exception. So
615 in this case the try/catch never falls through. */
621 /* Try to determine if we can fall out of the bottom of BLOCK. This guess
622 need not be 100% accurate; simply be conservative and return true if we
623 don't know. This is used only to avoid stupidly generating extra code.
624 If we're wrong, we'll just delete the extra code later. */
627 block_may_fallthru (const_tree block)
629 /* This CONST_CAST is okay because expr_last returns its argument
630 unmodified and we assign it to a const_tree. */
631 const_tree stmt = expr_last (CONST_CAST_TREE(block));
633 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
637 /* Easy cases. If the last statement of the block implies
638 control transfer, then we can't fall through. */
642 /* If SWITCH_LABELS is set, this is lowered, and represents a
643 branch to a selected label and hence can not fall through.
644 Otherwise SWITCH_BODY is set, and the switch can fall
646 return SWITCH_LABELS (stmt) == NULL_TREE;
649 if (block_may_fallthru (COND_EXPR_THEN (stmt)))
651 return block_may_fallthru (COND_EXPR_ELSE (stmt));
654 return block_may_fallthru (BIND_EXPR_BODY (stmt));
657 return try_catch_may_fallthru (stmt);
659 case TRY_FINALLY_EXPR:
660 /* The finally clause is always executed after the try clause,
661 so if it does not fall through, then the try-finally will not
662 fall through. Otherwise, if the try clause does not fall
663 through, then when the finally clause falls through it will
664 resume execution wherever the try clause was going. So the
665 whole try-finally will only fall through if both the try
666 clause and the finally clause fall through. */
667 return (block_may_fallthru (TREE_OPERAND (stmt, 0))
668 && block_may_fallthru (TREE_OPERAND (stmt, 1)));
671 if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)
672 stmt = TREE_OPERAND (stmt, 1);
678 /* Functions that do not return do not fall through. */
679 return (call_expr_flags (stmt) & ECF_NORETURN) == 0;
681 case CLEANUP_POINT_EXPR:
682 return block_may_fallthru (TREE_OPERAND (stmt, 0));
685 return block_may_fallthru (TREE_OPERAND (stmt, 1));
691 return lang_hooks.block_may_fallthru (stmt);
696 /* Try to determine if we can continue executing the statement
697 immediately following STMT. This guess need not be 100% accurate;
698 simply be conservative and return true if we don't know. This is
699 used only to avoid stupidly generating extra code. If we're wrong,
700 we'll just delete the extra code later. */
703 gimple_stmt_may_fallthru (gimple stmt)
708 switch (gimple_code (stmt))
713 /* Easy cases. If the last statement of the seq implies
714 control transfer, then we can't fall through. */
718 /* Switch has already been lowered and represents a branch
719 to a selected label and hence can't fall through. */
723 /* GIMPLE_COND's are already lowered into a two-way branch. They
724 can't fall through. */
728 return gimple_seq_may_fallthru (gimple_bind_body (stmt));
731 if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH)
732 return gimple_try_catch_may_fallthru (stmt);
734 /* It must be a GIMPLE_TRY_FINALLY. */
736 /* The finally clause is always executed after the try clause,
737 so if it does not fall through, then the try-finally will not
738 fall through. Otherwise, if the try clause does not fall
739 through, then when the finally clause falls through it will
740 resume execution wherever the try clause was going. So the
741 whole try-finally will only fall through if both the try
742 clause and the finally clause fall through. */
743 return (gimple_seq_may_fallthru (gimple_try_eval (stmt))
744 && gimple_seq_may_fallthru (gimple_try_cleanup (stmt)));
747 return (gimple_seq_may_fallthru (gimple_eh_else_n_body (stmt))
748 || gimple_seq_may_fallthru (gimple_eh_else_e_body (stmt)));
751 /* Functions that do not return do not fall through. */
752 return (gimple_call_flags (stmt) & ECF_NORETURN) == 0;
760 /* Same as gimple_stmt_may_fallthru, but for the gimple sequence SEQ. */
763 gimple_seq_may_fallthru (gimple_seq seq)
765 return gimple_stmt_may_fallthru (gimple_seq_last_stmt (seq));
769 /* Lower a GIMPLE_RETURN GSI. DATA is passed through the recursion. */
772 lower_gimple_return (gimple_stmt_iterator *gsi, struct lower_data *data)
774 gimple stmt = gsi_stmt (*gsi);
777 return_statements_t tmp_rs;
779 /* Match this up with an existing return statement that's been created. */
780 for (i = VEC_length (return_statements_t, data->return_statements) - 1;
783 tmp_rs = *VEC_index (return_statements_t, data->return_statements, i);
785 if (gimple_return_retval (stmt) == gimple_return_retval (tmp_rs.stmt))
787 /* Remove the line number from the representative return statement.
788 It now fills in for many such returns. Failure to remove this
789 will result in incorrect results for coverage analysis. */
790 gimple_set_location (tmp_rs.stmt, UNKNOWN_LOCATION);
796 /* Not found. Create a new label and record the return statement. */
797 tmp_rs.label = create_artificial_label (cfun->function_end_locus);
799 VEC_safe_push (return_statements_t, heap, data->return_statements, &tmp_rs);
801 /* Generate a goto statement and remove the return statement. */
803 /* When not optimizing, make sure user returns are preserved. */
804 if (!optimize && gimple_has_location (stmt))
805 DECL_ARTIFICIAL (tmp_rs.label) = 0;
806 t = gimple_build_goto (tmp_rs.label);
807 gimple_set_location (t, gimple_location (stmt));
808 gimple_set_block (t, gimple_block (stmt));
809 gsi_insert_before (gsi, t, GSI_SAME_STMT);
810 gsi_remove (gsi, false);
813 /* Lower a __builtin_setjmp GSI.
815 __builtin_setjmp is passed a pointer to an array of five words (not
816 all will be used on all machines). It operates similarly to the C
817 library function of the same name, but is more efficient.
819 It is lowered into 3 other builtins, namely __builtin_setjmp_setup,
820 __builtin_setjmp_dispatcher and __builtin_setjmp_receiver, but with
821 __builtin_setjmp_dispatcher shared among all the instances; that's
822 why it is only emitted at the end by lower_function_body.
824 After full lowering, the body of the function should look like:
833 __builtin_setjmp_setup (&buf, &<D1847>);
837 __builtin_setjmp_receiver (&<D1847>);
840 if (D.1844 == 0) goto <D1848>; else goto <D1849>;
844 __builtin_setjmp_setup (&buf, &<D2847>);
848 __builtin_setjmp_receiver (&<D2847>);
851 if (D.2844 == 0) goto <D2848>; else goto <D2849>;
857 <D3853>: [non-local];
858 setjmpvar.0 = __builtin_setjmp_dispatcher (&<D3853>);
862 The dispatcher block will be both the unique destination of all the
863 abnormal call edges and the unique source of all the abnormal edges
864 to the receivers, thus keeping the complexity explosion localized. */
867 lower_builtin_setjmp (gimple_stmt_iterator *gsi)
869 gimple stmt = gsi_stmt (*gsi);
870 location_t loc = gimple_location (stmt);
871 tree cont_label = create_artificial_label (loc);
872 tree next_label = create_artificial_label (loc);
876 /* NEXT_LABEL is the label __builtin_longjmp will jump to. Its address is
877 passed to both __builtin_setjmp_setup and __builtin_setjmp_receiver. */
878 FORCED_LABEL (next_label) = 1;
880 dest = gimple_call_lhs (stmt);
882 /* Build '__builtin_setjmp_setup (BUF, NEXT_LABEL)' and insert. */
883 arg = build_addr (next_label, current_function_decl);
884 t = builtin_decl_implicit (BUILT_IN_SETJMP_SETUP);
885 g = gimple_build_call (t, 2, gimple_call_arg (stmt, 0), arg);
886 gimple_set_location (g, loc);
887 gimple_set_block (g, gimple_block (stmt));
888 gsi_insert_before (gsi, g, GSI_SAME_STMT);
890 /* Build 'DEST = 0' and insert. */
893 g = gimple_build_assign (dest, build_zero_cst (TREE_TYPE (dest)));
894 gimple_set_location (g, loc);
895 gimple_set_block (g, gimple_block (stmt));
896 gsi_insert_before (gsi, g, GSI_SAME_STMT);
899 /* Build 'goto CONT_LABEL' and insert. */
900 g = gimple_build_goto (cont_label);
901 gsi_insert_before (gsi, g, GSI_SAME_STMT);
903 /* Build 'NEXT_LABEL:' and insert. */
904 g = gimple_build_label (next_label);
905 gsi_insert_before (gsi, g, GSI_SAME_STMT);
907 /* Build '__builtin_setjmp_receiver (NEXT_LABEL)' and insert. */
908 arg = build_addr (next_label, current_function_decl);
909 t = builtin_decl_implicit (BUILT_IN_SETJMP_RECEIVER);
910 g = gimple_build_call (t, 1, arg);
911 gimple_set_location (g, loc);
912 gimple_set_block (g, gimple_block (stmt));
913 gsi_insert_before (gsi, g, GSI_SAME_STMT);
915 /* Build 'DEST = 1' and insert. */
918 g = gimple_build_assign (dest, fold_convert_loc (loc, TREE_TYPE (dest),
920 gimple_set_location (g, loc);
921 gimple_set_block (g, gimple_block (stmt));
922 gsi_insert_before (gsi, g, GSI_SAME_STMT);
925 /* Build 'CONT_LABEL:' and insert. */
926 g = gimple_build_label (cont_label);
927 gsi_insert_before (gsi, g, GSI_SAME_STMT);
929 /* Remove the call to __builtin_setjmp. */
930 gsi_remove (gsi, false);
934 /* Record the variables in VARS into function FN. */
937 record_vars_into (tree vars, tree fn)
939 if (fn != current_function_decl)
940 push_cfun (DECL_STRUCT_FUNCTION (fn));
942 for (; vars; vars = DECL_CHAIN (vars))
946 /* BIND_EXPRs contains also function/type/constant declarations
947 we don't need to care about. */
948 if (TREE_CODE (var) != VAR_DECL)
951 /* Nothing to do in this case. */
952 if (DECL_EXTERNAL (var))
955 /* Record the variable. */
956 add_local_decl (cfun, var);
957 if (gimple_referenced_vars (cfun))
958 add_referenced_var (var);
961 if (fn != current_function_decl)
966 /* Record the variables in VARS into current_function_decl. */
969 record_vars (tree vars)
971 record_vars_into (vars, current_function_decl);