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1c4a429a JH |
1 | /* Callgraph handling code. |
2 | Copyright (C) 2003 Free Software Foundation, Inc. | |
3 | Contributed by Jan Hubicka | |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to the Free | |
19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
20 | 02111-1307, USA. */ | |
21 | ||
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "tree-inline.h" | |
28 | #include "langhooks.h" | |
29 | #include "hashtab.h" | |
30 | #include "toplev.h" | |
31 | #include "flags.h" | |
32 | #include "ggc.h" | |
33 | #include "debug.h" | |
34 | #include "target.h" | |
35 | #include "cgraph.h" | |
dafc5b82 | 36 | #include "diagnostic.h" |
1c4a429a JH |
37 | |
38 | static void cgraph_expand_functions PARAMS ((void)); | |
39 | static void cgraph_mark_functions_to_output PARAMS ((void)); | |
40 | static void cgraph_expand_function PARAMS ((struct cgraph_node *)); | |
41 | static tree record_call_1 PARAMS ((tree *, int *, void *)); | |
dafc5b82 | 42 | static void cgraph_mark_local_functions PARAMS ((void)); |
18d13f34 JH |
43 | static void cgraph_mark_functions_to_inline_once PARAMS ((void)); |
44 | static void cgraph_optimize_function PARAMS ((struct cgraph_node *)); | |
1c4a429a JH |
45 | |
46 | /* Analyze function once it is parsed. Set up the local information | |
47 | available - create cgraph edges for function calles via BODY. */ | |
48 | ||
49 | void | |
50 | cgraph_finalize_function (decl, body) | |
51 | tree decl; | |
52 | tree body ATTRIBUTE_UNUSED; | |
53 | { | |
54 | struct cgraph_node *node = cgraph_node (decl); | |
55 | ||
56 | node->decl = decl; | |
57 | ||
18d13f34 | 58 | node->local.can_inline_once = tree_inlinable_function_p (decl, 1); |
dafc5b82 | 59 | if (flag_inline_trees) |
18d13f34 | 60 | node->local.inline_many = tree_inlinable_function_p (decl, 0); |
dafc5b82 JH |
61 | else |
62 | node->local.inline_many = 0; | |
1c4a429a JH |
63 | |
64 | (*debug_hooks->deferred_inline_function) (decl); | |
65 | } | |
66 | ||
67 | static struct cgraph_node *queue = NULL; | |
68 | ||
69 | /* Notify finalize_compilation_unit that given node is reachable | |
70 | or needed. */ | |
71 | void | |
72 | cgraph_mark_needed_node (node, needed) | |
73 | struct cgraph_node *node; | |
74 | int needed; | |
75 | { | |
76 | if (needed) | |
77 | { | |
78 | if (DECL_SAVED_TREE (node->decl)) | |
79 | announce_function (node->decl); | |
80 | node->needed = 1; | |
81 | } | |
82 | if (!node->reachable) | |
83 | { | |
84 | node->reachable = 1; | |
85 | if (DECL_SAVED_TREE (node->decl)) | |
86 | { | |
87 | node->aux = queue; | |
88 | queue = node; | |
89 | } | |
90 | } | |
91 | } | |
92 | ||
93 | /* Walk tree and record all calls. Called via walk_tree. */ | |
94 | static tree | |
95 | record_call_1 (tp, walk_subtrees, data) | |
96 | tree *tp; | |
97 | int *walk_subtrees; | |
98 | void *data; | |
99 | { | |
100 | /* Record dereferences to the functions. This makes the functions | |
101 | reachable unconditionally. */ | |
102 | if (TREE_CODE (*tp) == ADDR_EXPR) | |
103 | { | |
104 | tree decl = TREE_OPERAND (*tp, 0); | |
105 | if (TREE_CODE (decl) == FUNCTION_DECL) | |
106 | cgraph_mark_needed_node (cgraph_node (decl), 1); | |
107 | } | |
108 | else if (TREE_CODE (*tp) == CALL_EXPR) | |
109 | { | |
110 | tree decl = TREE_OPERAND (*tp, 0); | |
111 | if (TREE_CODE (decl) == ADDR_EXPR) | |
112 | decl = TREE_OPERAND (decl, 0); | |
113 | if (TREE_CODE (decl) == FUNCTION_DECL) | |
114 | { | |
115 | if (DECL_BUILT_IN (decl)) | |
116 | return NULL; | |
117 | cgraph_record_call (data, decl); | |
118 | walk_tree (&TREE_OPERAND (*tp, 1), record_call_1, data, NULL); | |
119 | *walk_subtrees = 0; | |
120 | } | |
121 | } | |
122 | return NULL; | |
123 | } | |
124 | ||
125 | /* Create cgraph edges for function calles via BODY. */ | |
126 | ||
127 | void | |
128 | cgraph_create_edges (decl, body) | |
129 | tree decl; | |
130 | tree body; | |
131 | { | |
132 | walk_tree (&body, record_call_1, decl, NULL); | |
133 | } | |
134 | ||
135 | /* Analyze the whole compilation unit once it is parsed completely. */ | |
136 | ||
137 | void | |
138 | cgraph_finalize_compilation_unit () | |
139 | { | |
140 | struct cgraph_node *node; | |
141 | struct cgraph_edge *edge; | |
142 | ||
143 | /* Collect entry points to the unit. */ | |
144 | ||
145 | if (!quiet_flag) | |
146 | fprintf (stderr, "\n\nUnit entry points:"); | |
147 | ||
148 | for (node = cgraph_nodes; node; node = node->next) | |
149 | { | |
150 | tree decl = node->decl; | |
151 | ||
152 | if (!DECL_SAVED_TREE (decl)) | |
153 | continue; | |
154 | if ((TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl)) | |
155 | || (DECL_ASSEMBLER_NAME_SET_P (decl) | |
156 | && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))) | |
157 | { | |
158 | cgraph_mark_needed_node (node, 1); | |
159 | } | |
160 | } | |
161 | ||
162 | /* Propagate reachability flag and lower representation of all reachable | |
163 | functions. In the future, lowering will introduce new functions and | |
164 | new entry points on the way (by template instantiation and virtual | |
165 | method table generation for instance). */ | |
166 | while (queue) | |
167 | { | |
168 | tree decl = queue->decl; | |
169 | ||
170 | node = queue; | |
171 | queue = queue->aux; | |
172 | if (node->lowered || !node->reachable || !DECL_SAVED_TREE (decl)) | |
173 | abort (); | |
174 | ||
175 | /* At the moment frontend automatically emits all nested functions. */ | |
176 | if (node->nested) | |
177 | { | |
178 | struct cgraph_node *node2; | |
179 | ||
180 | for (node2 = node->nested; node2; node2 = node2->next_nested) | |
181 | if (!node2->reachable) | |
182 | cgraph_mark_needed_node (node2, 0); | |
183 | } | |
184 | ||
185 | if (lang_hooks.callgraph.lower_function) | |
186 | (*lang_hooks.callgraph.lower_function) (decl); | |
187 | /* First kill forward declaration so reverse inling works properly. */ | |
188 | cgraph_create_edges (decl, DECL_SAVED_TREE (decl)); | |
189 | ||
190 | for (edge = node->callees; edge; edge = edge->next_callee) | |
191 | { | |
192 | if (!edge->callee->reachable) | |
193 | cgraph_mark_needed_node (edge->callee, 0); | |
194 | } | |
195 | node->lowered = true; | |
196 | } | |
197 | if (!quiet_flag) | |
198 | fprintf (stderr, "\n\nReclaiming functions:"); | |
199 | ||
200 | for (node = cgraph_nodes; node; node = node->next) | |
201 | { | |
202 | tree decl = node->decl; | |
203 | ||
204 | if (!node->reachable && DECL_SAVED_TREE (decl)) | |
205 | { | |
18d13f34 | 206 | cgraph_remove_node (node); |
1c4a429a JH |
207 | announce_function (decl); |
208 | } | |
209 | } | |
210 | ggc_collect (); | |
211 | } | |
212 | ||
213 | /* Figure out what functions we want to assemble. */ | |
214 | ||
215 | static void | |
216 | cgraph_mark_functions_to_output () | |
217 | { | |
218 | struct cgraph_node *node; | |
219 | ||
220 | /* Figure out functions we want to assemble. */ | |
221 | for (node = cgraph_nodes; node; node = node->next) | |
222 | { | |
223 | tree decl = node->decl; | |
224 | ||
225 | if (DECL_SAVED_TREE (decl) | |
226 | && (node->needed | |
18d13f34 JH |
227 | || (!node->local.inline_many && !node->global.inline_once |
228 | && node->reachable) | |
1c4a429a JH |
229 | || TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl))) |
230 | && !TREE_ASM_WRITTEN (decl) && !node->origin | |
231 | && !DECL_EXTERNAL (decl)) | |
232 | node->output = 1; | |
233 | } | |
234 | } | |
235 | ||
18d13f34 JH |
236 | /* Optimize the function before expansion. */ |
237 | static void | |
238 | cgraph_optimize_function (node) | |
239 | struct cgraph_node *node; | |
240 | { | |
241 | tree decl = node->decl; | |
242 | ||
243 | if (flag_inline_trees) | |
244 | optimize_inline_calls (decl); | |
245 | if (node->nested) | |
246 | { | |
247 | for (node = node->nested; node; node = node->next_nested) | |
248 | cgraph_optimize_function (node); | |
249 | } | |
250 | } | |
251 | ||
1c4a429a JH |
252 | /* Expand function specified by NODE. */ |
253 | static void | |
254 | cgraph_expand_function (node) | |
255 | struct cgraph_node *node; | |
256 | { | |
257 | tree decl = node->decl; | |
258 | ||
259 | announce_function (decl); | |
18d13f34 JH |
260 | |
261 | cgraph_optimize_function (node); | |
dafc5b82 JH |
262 | |
263 | /* Avoid RTL inlining from taking place. */ | |
1c4a429a | 264 | (*lang_hooks.callgraph.expand_function) (decl); |
18d13f34 JH |
265 | |
266 | /* When we decided to inline the function once, we never ever should need to | |
267 | output it separately. */ | |
268 | if (node->global.inline_once) | |
269 | abort (); | |
270 | if (!node->local.inline_many | |
271 | || !node->callers) | |
1c4a429a JH |
272 | DECL_SAVED_TREE (decl) = NULL; |
273 | current_function_decl = NULL; | |
274 | } | |
275 | ||
276 | ||
277 | /* Expand all functions that must be output. | |
278 | ||
279 | Attempt to topologically sort the nodes so function is output when | |
280 | all called functions are already assembled to allow data to be propagated | |
281 | accross the callgraph. Use stack to get smaller distance between function | |
282 | and it's callees (later we may use more sophisticated algorithm for | |
283 | function reordering, we will likely want to use subsections to make output | |
284 | functions to appear in top-down order, not bottom-up they are assembled). */ | |
285 | ||
286 | static void | |
287 | cgraph_expand_functions () | |
288 | { | |
289 | struct cgraph_node *node, *node2; | |
290 | struct cgraph_node **stack = | |
291 | xcalloc (sizeof (struct cgraph_node *), cgraph_n_nodes); | |
292 | struct cgraph_node **order = | |
293 | xcalloc (sizeof (struct cgraph_node *), cgraph_n_nodes); | |
294 | int stack_size = 0; | |
295 | int order_pos = 0; | |
296 | struct cgraph_edge *edge, last; | |
297 | int i; | |
298 | ||
299 | cgraph_mark_functions_to_output (); | |
300 | ||
301 | /* We have to deal with cycles nicely, so use depth first traversal | |
302 | algorithm. Ignore the fact that some functions won't need to be output | |
303 | and put them into order as well, so we get dependencies right trought inlined | |
304 | functions. */ | |
305 | for (node = cgraph_nodes; node; node = node->next) | |
306 | node->aux = NULL; | |
307 | for (node = cgraph_nodes; node; node = node->next) | |
308 | if (node->output && !node->aux) | |
309 | { | |
310 | node2 = node; | |
311 | if (!node->callers) | |
312 | node->aux = &last; | |
313 | else | |
314 | node->aux = node->callers; | |
315 | while (node2) | |
316 | { | |
317 | while (node2->aux != &last) | |
318 | { | |
319 | edge = node2->aux; | |
320 | if (edge->next_caller) | |
321 | node2->aux = edge->next_caller; | |
322 | else | |
323 | node2->aux = &last; | |
324 | if (!edge->caller->aux) | |
325 | { | |
326 | if (!edge->caller->callers) | |
327 | edge->caller->aux = &last; | |
328 | else | |
329 | edge->caller->aux = edge->caller->callers; | |
330 | stack[stack_size++] = node2; | |
331 | node2 = edge->caller; | |
332 | break; | |
333 | } | |
334 | } | |
335 | if (node2->aux == &last) | |
336 | { | |
337 | order[order_pos++] = node2; | |
338 | if (stack_size) | |
339 | node2 = stack[--stack_size]; | |
340 | else | |
341 | node2 = NULL; | |
342 | } | |
343 | } | |
344 | } | |
6a87d634 | 345 | for (i = order_pos - 1; i >= 0; i--) |
1c4a429a JH |
346 | { |
347 | node = order[i]; | |
348 | if (node->output) | |
349 | { | |
350 | if (!node->reachable) | |
351 | abort (); | |
352 | node->output = 0; | |
353 | cgraph_expand_function (node); | |
354 | } | |
355 | } | |
356 | free (stack); | |
357 | free (order); | |
358 | } | |
359 | ||
dafc5b82 JH |
360 | /* Mark all local functions. |
361 | We can not use node->needed directly as it is modified during | |
362 | execution of cgraph_optimize. */ | |
363 | ||
364 | static void | |
365 | cgraph_mark_local_functions () | |
366 | { | |
367 | struct cgraph_node *node; | |
368 | ||
369 | if (!quiet_flag) | |
370 | fprintf (stderr, "\n\nMarking local functions:"); | |
371 | ||
372 | /* Figure out functions we want to assemble. */ | |
373 | for (node = cgraph_nodes; node; node = node->next) | |
374 | { | |
375 | node->local.local = (!node->needed | |
376 | && DECL_SAVED_TREE (node->decl) | |
377 | && !TREE_PUBLIC (node->decl)); | |
378 | if (node->local.local) | |
379 | announce_function (node->decl); | |
380 | } | |
381 | } | |
382 | ||
18d13f34 JH |
383 | /* Decide what function should be inlined because they are invoked once |
384 | (so inlining won't result in duplication of the code). */ | |
385 | ||
386 | static void | |
387 | cgraph_mark_functions_to_inline_once () | |
388 | { | |
389 | struct cgraph_node *node, *node1; | |
390 | ||
391 | if (!quiet_flag) | |
392 | fprintf (stderr, "\n\nMarking functions to inline once:"); | |
393 | ||
394 | /* Now look for function called only once and mark them to inline. From this | |
395 | point number of calls to given function won't grow. */ | |
396 | for (node = cgraph_nodes; node; node = node->next) | |
397 | { | |
398 | if (node->callers && !node->callers->next_caller && !node->needed | |
399 | && node->local.can_inline_once) | |
400 | { | |
401 | bool ok = true; | |
402 | ||
403 | /* Verify that we won't duplicate the caller. */ | |
404 | for (node1 = node->callers->caller; | |
405 | node1->local.inline_many | |
406 | && node1->callers | |
407 | && ok; | |
408 | node1 = node1->callers->caller) | |
409 | if (node1->callers->next_caller || node1->needed) | |
410 | ok = false; | |
411 | if (ok) | |
412 | { | |
413 | node->global.inline_once = true; | |
414 | announce_function (node->decl); | |
415 | } | |
416 | } | |
417 | } | |
418 | } | |
419 | ||
dafc5b82 | 420 | |
1c4a429a JH |
421 | /* Perform simple optimizations based on callgraph. */ |
422 | ||
423 | void | |
424 | cgraph_optimize () | |
425 | { | |
426 | struct cgraph_node *node; | |
427 | bool changed = true; | |
1c4a429a | 428 | |
dafc5b82 JH |
429 | cgraph_mark_local_functions (); |
430 | ||
18d13f34 JH |
431 | cgraph_mark_functions_to_inline_once (); |
432 | ||
dafc5b82 | 433 | cgraph_global_info_ready = true; |
1c4a429a JH |
434 | if (!quiet_flag) |
435 | fprintf (stderr, "\n\nAssembling functions:"); | |
436 | ||
437 | /* Output everything. | |
438 | ??? Our inline heuristic may decide to not inline functions previously | |
439 | marked as inlinable thus adding new function bodies that must be output. | |
440 | Later we should move all inlining decisions to callgraph code to make | |
441 | this impossible. */ | |
442 | cgraph_expand_functions (); | |
dafc5b82 JH |
443 | if (!quiet_flag) |
444 | fprintf (stderr, "\n\nAssembling functions that failed to inline:"); | |
445 | while (changed && !errorcount && !sorrycount) | |
1c4a429a JH |
446 | { |
447 | changed = false; | |
448 | for (node = cgraph_nodes; node; node = node->next) | |
449 | { | |
dafc5b82 JH |
450 | tree decl = node->decl; |
451 | if (!node->origin | |
452 | && !TREE_ASM_WRITTEN (decl) | |
453 | && DECL_SAVED_TREE (decl) | |
454 | && !DECL_EXTERNAL (decl)) | |
455 | { | |
456 | struct cgraph_edge *edge; | |
457 | ||
458 | for (edge = node->callers; edge; edge = edge->next_caller) | |
459 | if (TREE_ASM_WRITTEN (edge->caller->decl)) | |
460 | { | |
461 | changed = true; | |
462 | cgraph_expand_function (node); | |
463 | break; | |
464 | } | |
465 | } | |
1c4a429a JH |
466 | } |
467 | } | |
1c4a429a | 468 | } |