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