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Commit | Line | Data |
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242229bb JH |
1 | /* A pass for lowering trees to RTL. |
2 | Copyright (C) 2004 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GCC. | |
5 | ||
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) | |
9 | any later version. | |
10 | ||
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. | |
15 | ||
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. */ | |
20 | ||
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "tree.h" | |
26 | #include "rtl.h" | |
27 | #include "tm_p.h" | |
28 | #include "basic-block.h" | |
29 | #include "function.h" | |
30 | #include "expr.h" | |
31 | #include "langhooks.h" | |
32 | #include "tree-flow.h" | |
33 | #include "timevar.h" | |
34 | #include "tree-dump.h" | |
35 | #include "tree-pass.h" | |
36 | #include "except.h" | |
37 | #include "flags.h" | |
80c7a9eb RH |
38 | |
39 | ||
727a31fa RH |
40 | /* Expand variables in the unexpanded_var_list. */ |
41 | ||
42 | static void | |
43 | expand_used_vars (void) | |
44 | { | |
45 | tree cell; | |
46 | ||
47 | cfun->unexpanded_var_list = nreverse (cfun->unexpanded_var_list); | |
48 | ||
49 | for (cell = cfun->unexpanded_var_list; cell; cell = TREE_CHAIN (cell)) | |
50 | expand_var (TREE_VALUE (cell)); | |
51 | ||
52 | cfun->unexpanded_var_list = NULL_TREE; | |
53 | } | |
54 | ||
55 | ||
80c7a9eb RH |
56 | /* A subroutine of expand_gimple_basic_block. Expand one COND_EXPR. |
57 | Returns a new basic block if we've terminated the current basic | |
58 | block and created a new one. */ | |
59 | ||
60 | static basic_block | |
61 | expand_gimple_cond_expr (basic_block bb, tree stmt) | |
62 | { | |
63 | basic_block new_bb, dest; | |
64 | edge new_edge; | |
65 | edge true_edge; | |
66 | edge false_edge; | |
67 | tree pred = COND_EXPR_COND (stmt); | |
68 | tree then_exp = COND_EXPR_THEN (stmt); | |
69 | tree else_exp = COND_EXPR_ELSE (stmt); | |
70 | rtx last; | |
71 | ||
72 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
73 | if (EXPR_LOCUS (stmt)) | |
74 | { | |
75 | emit_line_note (*(EXPR_LOCUS (stmt))); | |
76 | record_block_change (TREE_BLOCK (stmt)); | |
77 | } | |
78 | ||
79 | /* These flags have no purpose in RTL land. */ | |
80 | true_edge->flags &= ~EDGE_TRUE_VALUE; | |
81 | false_edge->flags &= ~EDGE_FALSE_VALUE; | |
82 | ||
83 | /* We can either have a pure conditional jump with one fallthru edge or | |
84 | two-way jump that needs to be decomposed into two basic blocks. */ | |
85 | if (TREE_CODE (then_exp) == GOTO_EXPR && IS_EMPTY_STMT (else_exp)) | |
86 | { | |
87 | jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp))); | |
88 | return NULL; | |
89 | } | |
90 | if (TREE_CODE (else_exp) == GOTO_EXPR && IS_EMPTY_STMT (then_exp)) | |
91 | { | |
92 | jumpifnot (pred, label_rtx (GOTO_DESTINATION (else_exp))); | |
93 | return NULL; | |
94 | } | |
95 | if (TREE_CODE (then_exp) != GOTO_EXPR || TREE_CODE (else_exp) != GOTO_EXPR) | |
96 | abort (); | |
97 | ||
98 | jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp))); | |
99 | last = get_last_insn (); | |
100 | expand_expr (else_exp, const0_rtx, VOIDmode, 0); | |
101 | ||
102 | BB_END (bb) = last; | |
103 | if (BARRIER_P (BB_END (bb))) | |
104 | BB_END (bb) = PREV_INSN (BB_END (bb)); | |
105 | update_bb_for_insn (bb); | |
106 | ||
107 | new_bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb); | |
108 | dest = false_edge->dest; | |
109 | redirect_edge_succ (false_edge, new_bb); | |
110 | false_edge->flags |= EDGE_FALLTHRU; | |
111 | new_bb->count = false_edge->count; | |
112 | new_bb->frequency = EDGE_FREQUENCY (false_edge); | |
113 | new_edge = make_edge (new_bb, dest, 0); | |
114 | new_edge->probability = REG_BR_PROB_BASE; | |
115 | new_edge->count = new_bb->count; | |
116 | if (BARRIER_P (BB_END (new_bb))) | |
117 | BB_END (new_bb) = PREV_INSN (BB_END (new_bb)); | |
118 | update_bb_for_insn (new_bb); | |
119 | ||
120 | if (dump_file) | |
121 | { | |
122 | dump_bb (bb, dump_file, 0); | |
123 | dump_bb (new_bb, dump_file, 0); | |
124 | } | |
125 | ||
126 | return new_bb; | |
127 | } | |
128 | ||
129 | /* A subroutine of expand_gimple_basic_block. Expand one CALL_EXPR | |
224e770b RH |
130 | that has CALL_EXPR_TAILCALL set. Returns non-null if we actually |
131 | generated a tail call (something that might be denied by the ABI | |
132 | rules governing the call; see calls.c). */ | |
80c7a9eb RH |
133 | |
134 | static basic_block | |
135 | expand_gimple_tailcall (basic_block bb, tree stmt) | |
136 | { | |
137 | rtx last = get_last_insn (); | |
224e770b RH |
138 | edge e; |
139 | int probability; | |
140 | gcov_type count; | |
80c7a9eb RH |
141 | |
142 | expand_expr_stmt (stmt); | |
143 | ||
144 | for (last = NEXT_INSN (last); last; last = NEXT_INSN (last)) | |
224e770b RH |
145 | if (CALL_P (last) && SIBLING_CALL_P (last)) |
146 | goto found; | |
80c7a9eb | 147 | |
224e770b | 148 | return NULL; |
80c7a9eb | 149 | |
224e770b RH |
150 | found: |
151 | /* ??? Wouldn't it be better to just reset any pending stack adjust? | |
152 | Any instructions emitted here are about to be deleted. */ | |
153 | do_pending_stack_adjust (); | |
154 | ||
155 | /* Remove any non-eh, non-abnormal edges that don't go to exit. */ | |
156 | /* ??? I.e. the fallthrough edge. HOWEVER! If there were to be | |
157 | EH or abnormal edges, we shouldn't have created a tail call in | |
158 | the first place. So it seems to me we should just be removing | |
159 | all edges here, or redirecting the existing fallthru edge to | |
160 | the exit block. */ | |
161 | ||
162 | e = bb->succ; | |
163 | probability = 0; | |
164 | count = 0; | |
165 | while (e) | |
166 | { | |
167 | edge next = e->succ_next; | |
168 | ||
169 | if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH))) | |
170 | { | |
171 | if (e->dest != EXIT_BLOCK_PTR) | |
80c7a9eb | 172 | { |
224e770b RH |
173 | e->dest->count -= e->count; |
174 | e->dest->frequency -= EDGE_FREQUENCY (e); | |
175 | if (e->dest->count < 0) | |
176 | e->dest->count = 0; | |
177 | if (e->dest->frequency < 0) | |
178 | e->dest->frequency = 0; | |
80c7a9eb | 179 | } |
224e770b RH |
180 | count += e->count; |
181 | probability += e->probability; | |
182 | remove_edge (e); | |
80c7a9eb | 183 | } |
224e770b RH |
184 | |
185 | e = next; | |
80c7a9eb RH |
186 | } |
187 | ||
224e770b RH |
188 | /* This is somewhat ugly: the call_expr expander often emits instructions |
189 | after the sibcall (to perform the function return). These confuse the | |
190 | find_sub_basic_blocks code, so we need to get rid of these. */ | |
191 | last = NEXT_INSN (last); | |
192 | if (!BARRIER_P (last)) | |
193 | abort (); | |
194 | while (NEXT_INSN (last)) | |
195 | { | |
196 | /* For instance an sqrt builtin expander expands if with | |
197 | sibcall in the then and label for `else`. */ | |
198 | if (LABEL_P (NEXT_INSN (last))) | |
199 | break; | |
200 | delete_insn (NEXT_INSN (last)); | |
201 | } | |
202 | ||
203 | e = make_edge (bb, EXIT_BLOCK_PTR, EDGE_ABNORMAL | EDGE_SIBCALL); | |
204 | e->probability += probability; | |
205 | e->count += count; | |
206 | BB_END (bb) = last; | |
207 | update_bb_for_insn (bb); | |
208 | ||
209 | if (NEXT_INSN (last)) | |
210 | { | |
211 | bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb); | |
212 | ||
213 | last = BB_END (bb); | |
214 | if (BARRIER_P (last)) | |
215 | BB_END (bb) = PREV_INSN (last); | |
216 | } | |
217 | ||
218 | return bb; | |
80c7a9eb RH |
219 | } |
220 | ||
242229bb JH |
221 | /* Expand basic block BB from GIMPLE trees to RTL. */ |
222 | ||
223 | static basic_block | |
80c7a9eb | 224 | expand_gimple_basic_block (basic_block bb, FILE * dump_file) |
242229bb JH |
225 | { |
226 | block_stmt_iterator bsi = bsi_start (bb); | |
227 | tree stmt = NULL; | |
228 | rtx note, last; | |
229 | edge e; | |
230 | ||
231 | if (dump_file) | |
232 | { | |
233 | tree_register_cfg_hooks (); | |
234 | dump_bb (bb, dump_file, 0); | |
235 | rtl_register_cfg_hooks (); | |
236 | } | |
237 | ||
238 | if (!bsi_end_p (bsi)) | |
239 | stmt = bsi_stmt (bsi); | |
240 | ||
241 | if (stmt && TREE_CODE (stmt) == LABEL_EXPR) | |
242 | { | |
243 | last = get_last_insn (); | |
244 | ||
4dfa0342 | 245 | expand_expr_stmt (stmt); |
242229bb | 246 | |
caf93cb0 | 247 | /* Java emits line number notes in the top of labels. |
242229bb JH |
248 | ??? Make this go away once line number notes are obsoleted. */ |
249 | BB_HEAD (bb) = NEXT_INSN (last); | |
4b4bf941 | 250 | if (NOTE_P (BB_HEAD (bb))) |
242229bb JH |
251 | BB_HEAD (bb) = NEXT_INSN (BB_HEAD (bb)); |
252 | bsi_next (&bsi); | |
253 | note = emit_note_after (NOTE_INSN_BASIC_BLOCK, BB_HEAD (bb)); | |
254 | } | |
255 | else | |
256 | note = BB_HEAD (bb) = emit_note (NOTE_INSN_BASIC_BLOCK); | |
257 | ||
258 | NOTE_BASIC_BLOCK (note) = bb; | |
259 | ||
260 | e = bb->succ; | |
261 | while (e) | |
262 | { | |
263 | edge next = e->succ_next; | |
264 | ||
265 | /* Clear EDGE_EXECUTABLE. This flag is never used in the backend. */ | |
266 | e->flags &= ~EDGE_EXECUTABLE; | |
267 | ||
268 | /* At the moment not all abnormal edges match the RTL representation. | |
269 | It is safe to remove them here as find_sub_basic_blocks will | |
270 | rediscover them. In the future we should get this fixed properly. */ | |
271 | if (e->flags & EDGE_ABNORMAL) | |
272 | remove_edge (e); | |
273 | ||
274 | e = next; | |
275 | } | |
276 | ||
277 | for (; !bsi_end_p (bsi); bsi_next (&bsi)) | |
278 | { | |
279 | tree stmt = bsi_stmt (bsi); | |
80c7a9eb | 280 | basic_block new_bb = NULL; |
242229bb JH |
281 | |
282 | if (!stmt) | |
283 | continue; | |
284 | ||
285 | /* Expand this statement, then evaluate the resulting RTL and | |
286 | fixup the CFG accordingly. */ | |
80c7a9eb RH |
287 | if (TREE_CODE (stmt) == COND_EXPR) |
288 | new_bb = expand_gimple_cond_expr (bb, stmt); | |
289 | else | |
242229bb | 290 | { |
80c7a9eb RH |
291 | tree call = get_call_expr_in (stmt); |
292 | if (call && CALL_EXPR_TAILCALL (call)) | |
293 | new_bb = expand_gimple_tailcall (bb, stmt); | |
294 | else | |
295 | expand_expr_stmt (stmt); | |
242229bb | 296 | } |
80c7a9eb RH |
297 | |
298 | if (new_bb) | |
299 | return new_bb; | |
242229bb JH |
300 | } |
301 | ||
302 | do_pending_stack_adjust (); | |
303 | ||
304 | /* Find the the block tail. The last insn is the block is the insn | |
305 | before a barrier and/or table jump insn. */ | |
306 | last = get_last_insn (); | |
4b4bf941 | 307 | if (BARRIER_P (last)) |
242229bb JH |
308 | last = PREV_INSN (last); |
309 | if (JUMP_TABLE_DATA_P (last)) | |
310 | last = PREV_INSN (PREV_INSN (last)); | |
311 | BB_END (bb) = last; | |
caf93cb0 | 312 | |
242229bb JH |
313 | if (dump_file) |
314 | dump_bb (bb, dump_file, 0); | |
315 | update_bb_for_insn (bb); | |
80c7a9eb | 316 | |
242229bb JH |
317 | return bb; |
318 | } | |
319 | ||
320 | ||
321 | /* Create a basic block for initialization code. */ | |
322 | ||
323 | static basic_block | |
324 | construct_init_block (void) | |
325 | { | |
326 | basic_block init_block, first_block; | |
327 | edge e; | |
328 | ||
242229bb JH |
329 | for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next) |
330 | if (e->dest == ENTRY_BLOCK_PTR->next_bb) | |
331 | break; | |
332 | ||
333 | init_block = create_basic_block (NEXT_INSN (get_insns ()), | |
334 | get_last_insn (), | |
335 | ENTRY_BLOCK_PTR); | |
336 | init_block->frequency = ENTRY_BLOCK_PTR->frequency; | |
337 | init_block->count = ENTRY_BLOCK_PTR->count; | |
338 | if (e) | |
339 | { | |
340 | first_block = e->dest; | |
341 | redirect_edge_succ (e, init_block); | |
342 | e = make_edge (init_block, first_block, EDGE_FALLTHRU); | |
343 | } | |
344 | else | |
345 | e = make_edge (init_block, EXIT_BLOCK_PTR, EDGE_FALLTHRU); | |
346 | e->probability = REG_BR_PROB_BASE; | |
347 | e->count = ENTRY_BLOCK_PTR->count; | |
348 | ||
349 | update_bb_for_insn (init_block); | |
350 | return init_block; | |
351 | } | |
352 | ||
353 | ||
354 | /* Create a block containing landing pads and similar stuff. */ | |
355 | ||
356 | static void | |
357 | construct_exit_block (void) | |
358 | { | |
359 | rtx head = get_last_insn (); | |
360 | rtx end; | |
361 | basic_block exit_block; | |
362 | edge e, e2, next; | |
363 | ||
caf93cb0 | 364 | /* Make sure the locus is set to the end of the function, so that |
242229bb | 365 | epilogue line numbers and warnings are set properly. */ |
6773e15f PB |
366 | #ifdef USE_MAPPED_LOCATION |
367 | if (cfun->function_end_locus != UNKNOWN_LOCATION) | |
368 | #else | |
242229bb | 369 | if (cfun->function_end_locus.file) |
6773e15f | 370 | #endif |
242229bb JH |
371 | input_location = cfun->function_end_locus; |
372 | ||
373 | /* The following insns belong to the top scope. */ | |
374 | record_block_change (DECL_INITIAL (current_function_decl)); | |
375 | ||
242229bb JH |
376 | /* Generate rtl for function exit. */ |
377 | expand_function_end (); | |
378 | ||
379 | end = get_last_insn (); | |
380 | if (head == end) | |
381 | return; | |
4b4bf941 | 382 | while (NEXT_INSN (head) && NOTE_P (NEXT_INSN (head))) |
242229bb | 383 | head = NEXT_INSN (head); |
80c7a9eb RH |
384 | exit_block = create_basic_block (NEXT_INSN (head), end, |
385 | EXIT_BLOCK_PTR->prev_bb); | |
242229bb JH |
386 | exit_block->frequency = EXIT_BLOCK_PTR->frequency; |
387 | exit_block->count = EXIT_BLOCK_PTR->count; | |
388 | for (e = EXIT_BLOCK_PTR->pred; e; e = next) | |
389 | { | |
390 | next = e->pred_next; | |
391 | if (!(e->flags & EDGE_ABNORMAL)) | |
392 | redirect_edge_succ (e, exit_block); | |
393 | } | |
394 | e = make_edge (exit_block, EXIT_BLOCK_PTR, EDGE_FALLTHRU); | |
395 | e->probability = REG_BR_PROB_BASE; | |
396 | e->count = EXIT_BLOCK_PTR->count; | |
397 | for (e2 = EXIT_BLOCK_PTR->pred; e2; e2 = e2->pred_next) | |
398 | if (e2 != e) | |
399 | { | |
400 | e->count -= e2->count; | |
401 | exit_block->count -= e2->count; | |
402 | exit_block->frequency -= EDGE_FREQUENCY (e2); | |
403 | } | |
404 | if (e->count < 0) | |
405 | e->count = 0; | |
406 | if (exit_block->count < 0) | |
407 | exit_block->count = 0; | |
408 | if (exit_block->frequency < 0) | |
409 | exit_block->frequency = 0; | |
410 | update_bb_for_insn (exit_block); | |
411 | } | |
412 | ||
242229bb JH |
413 | /* Translate the intermediate representation contained in the CFG |
414 | from GIMPLE trees to RTL. | |
415 | ||
416 | We do conversion per basic block and preserve/update the tree CFG. | |
417 | This implies we have to do some magic as the CFG can simultaneously | |
418 | consist of basic blocks containing RTL and GIMPLE trees. This can | |
61ada8ae | 419 | confuse the CFG hooks, so be careful to not manipulate CFG during |
242229bb JH |
420 | the expansion. */ |
421 | ||
422 | static void | |
423 | tree_expand_cfg (void) | |
424 | { | |
425 | basic_block bb, init_block; | |
426 | sbitmap blocks; | |
427 | ||
428 | if (dump_file) | |
429 | { | |
430 | fprintf (dump_file, "\n;; Function %s", | |
431 | (*lang_hooks.decl_printable_name) (current_function_decl, 2)); | |
432 | fprintf (dump_file, " (%s)\n", | |
433 | IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (current_function_decl))); | |
434 | } | |
435 | ||
6429e3be RH |
436 | /* Prepare the rtl middle end to start recording block changes. */ |
437 | reset_block_changes (); | |
438 | ||
727a31fa | 439 | /* Expand the variables recorded during gimple lowering. */ |
242229bb JH |
440 | expand_used_vars (); |
441 | ||
442 | /* Set up parameters and prepare for return, for the function. */ | |
b79c5284 | 443 | expand_function_start (current_function_decl); |
242229bb JH |
444 | |
445 | /* If this function is `main', emit a call to `__main' | |
446 | to run global initializers, etc. */ | |
447 | if (DECL_NAME (current_function_decl) | |
448 | && MAIN_NAME_P (DECL_NAME (current_function_decl)) | |
449 | && DECL_FILE_SCOPE_P (current_function_decl)) | |
450 | expand_main_function (); | |
451 | ||
452 | /* Write the flowgraph to a dot file. */ | |
453 | rtl_register_cfg_hooks (); | |
454 | ||
455 | init_block = construct_init_block (); | |
456 | ||
457 | FOR_BB_BETWEEN (bb, init_block->next_bb, EXIT_BLOCK_PTR, next_bb) | |
80c7a9eb | 458 | bb = expand_gimple_basic_block (bb, dump_file); |
242229bb JH |
459 | |
460 | construct_exit_block (); | |
461 | ||
462 | /* Convert from NOTE_INSN_EH_REGION style notes, and do other | |
463 | sorts of eh initialization. Delay this until after the | |
464 | initial rtl dump so that we can see the original nesting. */ | |
465 | convert_from_eh_region_ranges (); | |
466 | ||
467 | rebuild_jump_labels (get_insns ()); | |
468 | find_exception_handler_labels (); | |
469 | ||
470 | blocks = sbitmap_alloc (last_basic_block); | |
471 | sbitmap_ones (blocks); | |
472 | find_many_sub_basic_blocks (blocks); | |
473 | purge_all_dead_edges (0); | |
474 | sbitmap_free (blocks); | |
475 | ||
476 | compact_blocks (); | |
477 | #ifdef ENABLE_CHECKING | |
478 | verify_flow_info(); | |
479 | #endif | |
480 | } | |
481 | ||
482 | struct tree_opt_pass pass_expand = | |
483 | { | |
484 | "expand", /* name */ | |
485 | NULL, /* gate */ | |
486 | tree_expand_cfg, /* execute */ | |
487 | NULL, /* sub */ | |
488 | NULL, /* next */ | |
489 | 0, /* static_pass_number */ | |
490 | TV_EXPAND, /* tv_id */ | |
491 | /* ??? If TER is enabled, we actually receive GENERIC. */ | |
492 | PROP_gimple_leh | PROP_cfg, /* properties_required */ | |
493 | PROP_rtl, /* properties_provided */ | |
494 | PROP_gimple_leh, /* properties_destroyed */ | |
495 | 0, /* todo_flags_start */ | |
496 | 0 /* todo_flags_finish */ | |
497 | }; |