1 /* A pass for lowering trees to RTL.
2 Copyright (C) 2004 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
23 #include "coretypes.h"
28 #include "basic-block.h"
31 #include "langhooks.h"
32 #include "tree-flow.h"
34 #include "tree-dump.h"
35 #include "tree-pass.h"
39 /* Expand basic block BB from GIMPLE trees to RTL. */
42 expand_block (basic_block bb
, FILE * dump_file
)
44 block_stmt_iterator bsi
= bsi_start (bb
);
52 tree_register_cfg_hooks ();
53 dump_bb (bb
, dump_file
, 0);
54 rtl_register_cfg_hooks ();
58 stmt
= bsi_stmt (bsi
);
60 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
)
62 last
= get_last_insn ();
64 expand_expr_stmt (stmt
);
66 /* Java emits line number notes in the top of labels.
67 ??? Make this go away once line number notes are obsoleted. */
68 BB_HEAD (bb
) = NEXT_INSN (last
);
69 if (NOTE_P (BB_HEAD (bb
)))
70 BB_HEAD (bb
) = NEXT_INSN (BB_HEAD (bb
));
72 note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, BB_HEAD (bb
));
75 note
= BB_HEAD (bb
) = emit_note (NOTE_INSN_BASIC_BLOCK
);
77 NOTE_BASIC_BLOCK (note
) = bb
;
79 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
81 /* Clear EDGE_EXECUTABLE. This flag is never used in the backend. */
82 e
->flags
&= ~EDGE_EXECUTABLE
;
84 /* At the moment not all abnormal edges match the RTL representation.
85 It is safe to remove them here as find_sub_basic_blocks will
86 rediscover them. In the future we should get this fixed properly. */
87 if (e
->flags
& EDGE_ABNORMAL
)
91 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
93 tree stmt
= bsi_stmt (bsi
);
95 last
= get_last_insn ();
100 /* Expand this statement, then evaluate the resulting RTL and
101 fixup the CFG accordingly. */
102 switch (TREE_CODE (stmt
))
106 basic_block new_bb
, dest
;
110 tree pred
= COND_EXPR_COND (stmt
);
111 tree then_exp
= COND_EXPR_THEN (stmt
);
112 tree else_exp
= COND_EXPR_ELSE (stmt
);
113 rtx last
= get_last_insn ();
115 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
116 if (EXPR_LOCUS (stmt
))
118 emit_line_note (*(EXPR_LOCUS (stmt
)));
119 record_block_change (TREE_BLOCK (stmt
));
122 /* These flags have no purpose in RTL land. */
123 true_edge
->flags
&= ~EDGE_TRUE_VALUE
;
124 false_edge
->flags
&= ~EDGE_FALSE_VALUE
;
126 /* We can either have a pure conditional jump with one fallthru
127 edge or two-way jump that needs to be decomposed into two
129 if (TREE_CODE (then_exp
) == GOTO_EXPR
130 && TREE_CODE (else_exp
) == NOP_EXPR
)
132 jumpif (pred
, label_rtx (GOTO_DESTINATION (then_exp
)));
135 if (TREE_CODE (else_exp
) == GOTO_EXPR
136 && TREE_CODE (then_exp
) == NOP_EXPR
)
138 jumpifnot (pred
, label_rtx (GOTO_DESTINATION (else_exp
)));
141 if (TREE_CODE (then_exp
) != GOTO_EXPR
142 || TREE_CODE (else_exp
) != GOTO_EXPR
)
145 jumpif (pred
, label_rtx (GOTO_DESTINATION (then_exp
)));
146 last
= get_last_insn ();
147 expand_expr (else_exp
, const0_rtx
, VOIDmode
, 0);
150 if (BARRIER_P (BB_END (bb
)))
151 BB_END (bb
) = PREV_INSN (BB_END (bb
));
152 update_bb_for_insn (bb
);
154 new_bb
= create_basic_block (NEXT_INSN (last
), get_last_insn (), bb
);
155 dest
= false_edge
->dest
;
156 redirect_edge_succ (false_edge
, new_bb
);
157 false_edge
->flags
|= EDGE_FALLTHRU
;
158 new_bb
->count
= false_edge
->count
;
159 new_bb
->frequency
= EDGE_FREQUENCY (false_edge
);
160 new_edge
= make_edge (new_bb
, dest
, 0);
161 new_edge
->probability
= REG_BR_PROB_BASE
;
162 new_edge
->count
= new_bb
->count
;
163 if (BARRIER_P (BB_END (new_bb
)))
164 BB_END (new_bb
) = PREV_INSN (BB_END (new_bb
));
165 update_bb_for_insn (new_bb
);
169 dump_bb (bb
, dump_file
, 0);
170 dump_bb (new_bb
, dump_file
, 0);
175 /* Update after expansion of sibling call. */
179 expand_expr_stmt (stmt
);
180 for (last
= NEXT_INSN (last
); last
; last
= NEXT_INSN (last
))
182 if (CALL_P (last
) && SIBLING_CALL_P (last
))
188 do_pending_stack_adjust ();
190 FOR_EACH_EDGE (e
, bb
->succ
, ix
)
192 if (!(e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
)))
194 if (e
->dest
!= EXIT_BLOCK_PTR
)
196 e
->dest
->count
-= e
->count
;
197 e
->dest
->frequency
-= EDGE_FREQUENCY (e
);
198 if (e
->dest
->count
< 0)
200 if (e
->dest
->frequency
< 0)
201 e
->dest
->frequency
= 0;
204 probability
+= e
->probability
;
209 /* This is somewhat ugly: the call_expr expander often emits instructions
210 after the sibcall (to perform the function return). These confuse the
211 find_sub_basic_blocks code, so we need to get rid of these. */
212 last
= NEXT_INSN (last
);
213 if (!BARRIER_P (last
))
215 while (NEXT_INSN (last
))
217 /* For instance an sqrt builtin expander expands if with
218 sibcall in the then and label for `else`. */
219 if (LABEL_P (NEXT_INSN (last
)))
221 delete_insn (NEXT_INSN (last
));
223 e
= make_edge (bb
, EXIT_BLOCK_PTR
,
224 EDGE_ABNORMAL
| EDGE_SIBCALL
);
225 e
->probability
+= probability
;
228 update_bb_for_insn (bb
);
229 if (NEXT_INSN (last
))
230 bb
= create_basic_block (NEXT_INSN (last
), get_last_insn (), bb
);
238 expand_expr_stmt (stmt
);
243 do_pending_stack_adjust ();
245 /* Find the the block tail. The last insn is the block is the insn
246 before a barrier and/or table jump insn. */
247 last
= get_last_insn ();
248 if (BARRIER_P (last
))
249 last
= PREV_INSN (last
);
250 if (JUMP_TABLE_DATA_P (last
))
251 last
= PREV_INSN (PREV_INSN (last
));
255 dump_bb (bb
, dump_file
, 0);
256 update_bb_for_insn (bb
);
261 /* Create a basic block for initialization code. */
264 construct_init_block (void)
266 basic_block init_block
, first_block
;
270 expand_start_bindings_and_block (0, NULL_TREE
);
272 FOR_EACH_EDGE (e
, ENTRY_BLOCK_PTR
->succ
, ix
)
273 if (e
->dest
== ENTRY_BLOCK_PTR
->next_bb
)
276 init_block
= create_basic_block (NEXT_INSN (get_insns ()),
279 init_block
->frequency
= ENTRY_BLOCK_PTR
->frequency
;
280 init_block
->count
= ENTRY_BLOCK_PTR
->count
;
283 first_block
= e
->dest
;
284 redirect_edge_succ (e
, init_block
);
285 e
= make_edge (init_block
, first_block
, EDGE_FALLTHRU
);
288 e
= make_edge (init_block
, EXIT_BLOCK_PTR
, EDGE_FALLTHRU
);
289 e
->probability
= REG_BR_PROB_BASE
;
290 e
->count
= ENTRY_BLOCK_PTR
->count
;
292 update_bb_for_insn (init_block
);
297 /* Create a block containing landing pads and similar stuff. */
300 construct_exit_block (void)
302 rtx head
= get_last_insn ();
304 basic_block exit_block
;
308 /* Make sure the locus is set to the end of the function, so that
309 epilogue line numbers and warnings are set properly. */
310 #ifdef USE_MAPPED_LOCATION
311 if (cfun
->function_end_locus
!= UNKNOWN_LOCATION
)
313 if (cfun
->function_end_locus
.file
)
315 input_location
= cfun
->function_end_locus
;
317 /* The following insns belong to the top scope. */
318 record_block_change (DECL_INITIAL (current_function_decl
));
320 expand_end_bindings (NULL_TREE
, 1, 0);
322 /* Generate rtl for function exit. */
323 expand_function_end ();
325 end
= get_last_insn ();
328 while (NEXT_INSN (head
) && NOTE_P (NEXT_INSN (head
)))
329 head
= NEXT_INSN (head
);
330 exit_block
= create_basic_block (NEXT_INSN (head
), end
, EXIT_BLOCK_PTR
->prev_bb
);
331 exit_block
->frequency
= EXIT_BLOCK_PTR
->frequency
;
332 exit_block
->count
= EXIT_BLOCK_PTR
->count
;
334 FOR_EACH_EDGE (e
, EXIT_BLOCK_PTR
->pred
, ix
)
336 if (!(e
->flags
& EDGE_ABNORMAL
))
337 redirect_edge_succ (e
, exit_block
);
339 e
= make_edge (exit_block
, EXIT_BLOCK_PTR
, EDGE_FALLTHRU
);
340 e
->probability
= REG_BR_PROB_BASE
;
341 e
->count
= EXIT_BLOCK_PTR
->count
;
343 FOR_EACH_EDGE (e2
, EXIT_BLOCK_PTR
->pred
, ix
)
346 e
->count
-= e2
->count
;
347 exit_block
->count
-= e2
->count
;
348 exit_block
->frequency
-= EDGE_FREQUENCY (e2
);
352 if (exit_block
->count
< 0)
353 exit_block
->count
= 0;
354 if (exit_block
->frequency
< 0)
355 exit_block
->frequency
= 0;
356 update_bb_for_insn (exit_block
);
359 /* Translate the intermediate representation contained in the CFG
360 from GIMPLE trees to RTL.
362 We do conversion per basic block and preserve/update the tree CFG.
363 This implies we have to do some magic as the CFG can simultaneously
364 consist of basic blocks containing RTL and GIMPLE trees. This can
365 confuse the CFG hooks, so be careful to not manipulate CFG during
369 tree_expand_cfg (void)
371 basic_block bb
, init_block
;
376 fprintf (dump_file
, "\n;; Function %s",
377 (*lang_hooks
.decl_printable_name
) (current_function_decl
, 2));
378 fprintf (dump_file
, " (%s)\n",
379 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (current_function_decl
)));
382 /* Prepare the rtl middle end to start recording block changes. */
383 reset_block_changes ();
385 /* Expand the variables recorded during gimple lowering. This must
386 occur before the call to expand_function_start to ensure that
387 all used variables are expanded before we expand anything on the
388 PENDING_SIZES list. */
391 /* Set up parameters and prepare for return, for the function. */
392 expand_function_start (current_function_decl
);
394 /* If this function is `main', emit a call to `__main'
395 to run global initializers, etc. */
396 if (DECL_NAME (current_function_decl
)
397 && MAIN_NAME_P (DECL_NAME (current_function_decl
))
398 && DECL_FILE_SCOPE_P (current_function_decl
))
399 expand_main_function ();
401 /* Write the flowgraph to a dot file. */
402 rtl_register_cfg_hooks ();
404 init_block
= construct_init_block ();
406 FOR_BB_BETWEEN (bb
, init_block
->next_bb
, EXIT_BLOCK_PTR
, next_bb
)
407 bb
= expand_block (bb
, dump_file
);
409 construct_exit_block ();
411 /* Convert from NOTE_INSN_EH_REGION style notes, and do other
412 sorts of eh initialization. Delay this until after the
413 initial rtl dump so that we can see the original nesting. */
414 convert_from_eh_region_ranges ();
416 rebuild_jump_labels (get_insns ());
417 find_exception_handler_labels ();
419 blocks
= sbitmap_alloc (last_basic_block
);
420 sbitmap_ones (blocks
);
421 find_many_sub_basic_blocks (blocks
);
422 purge_all_dead_edges (0);
423 sbitmap_free (blocks
);
426 #ifdef ENABLE_CHECKING
431 struct tree_opt_pass pass_expand
=
435 tree_expand_cfg
, /* execute */
438 0, /* static_pass_number */
439 TV_EXPAND
, /* tv_id */
440 /* ??? If TER is enabled, we actually receive GENERIC. */
441 PROP_gimple_leh
| PROP_cfg
, /* properties_required */
442 PROP_rtl
, /* properties_provided */
443 PROP_gimple_leh
, /* properties_destroyed */
444 0, /* todo_flags_start */
445 0 /* todo_flags_finish */