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fee8b6da JH |
1 | /* Callgraph transformations to handle inlining |
2 | Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010, 2011 | |
3 | Free Software Foundation, Inc. | |
4 | Contributed by Jan Hubicka | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
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 | |
11 | version. | |
12 | ||
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 | |
16 | for more details. | |
17 | ||
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/>. */ | |
21 | ||
22 | /* The inline decisions are stored in callgraph in "inline plan" and | |
23 | applied later. | |
24 | ||
25 | To mark given call inline, use inline_call function. | |
26 | The function marks the edge inlinable and, if necessary, produces | |
27 | virtual clone in the callgraph representing the new copy of callee's | |
28 | function body. | |
29 | ||
30 | The inline plan is applied on given function body by inline_transform. */ | |
31 | ||
32 | #include "config.h" | |
33 | #include "system.h" | |
34 | #include "coretypes.h" | |
35 | #include "tm.h" | |
36 | #include "tree.h" | |
37 | #include "langhooks.h" | |
38 | #include "cgraph.h" | |
fee8b6da JH |
39 | #include "intl.h" |
40 | #include "coverage.h" | |
41 | #include "ggc.h" | |
42 | #include "tree-flow.h" | |
43 | #include "ipa-prop.h" | |
44 | #include "ipa-inline.h" | |
45 | #include "tree-inline.h" | |
516e0768 | 46 | #include "tree-pass.h" |
fee8b6da JH |
47 | |
48 | int ncalls_inlined; | |
49 | int nfunctions_inlined; | |
50 | ||
898b8927 | 51 | /* Scale frequency of NODE edges by FREQ_SCALE. */ |
fee8b6da JH |
52 | |
53 | static void | |
54 | update_noncloned_frequencies (struct cgraph_node *node, | |
898b8927 | 55 | int freq_scale) |
fee8b6da JH |
56 | { |
57 | struct cgraph_edge *e; | |
58 | ||
59 | /* We do not want to ignore high loop nest after freq drops to 0. */ | |
60 | if (!freq_scale) | |
61 | freq_scale = 1; | |
62 | for (e = node->callees; e; e = e->next_callee) | |
63 | { | |
fee8b6da JH |
64 | e->frequency = e->frequency * (gcov_type) freq_scale / CGRAPH_FREQ_BASE; |
65 | if (e->frequency > CGRAPH_FREQ_MAX) | |
66 | e->frequency = CGRAPH_FREQ_MAX; | |
67 | if (!e->inline_failed) | |
898b8927 JH |
68 | update_noncloned_frequencies (e->callee, freq_scale); |
69 | } | |
70 | for (e = node->indirect_calls; e; e = e->next_callee) | |
71 | { | |
72 | e->frequency = e->frequency * (gcov_type) freq_scale / CGRAPH_FREQ_BASE; | |
73 | if (e->frequency > CGRAPH_FREQ_MAX) | |
74 | e->frequency = CGRAPH_FREQ_MAX; | |
fee8b6da JH |
75 | } |
76 | } | |
77 | ||
a5b1779f JH |
78 | /* We removed or are going to remove the last call to NODE. |
79 | Return true if we can and want proactively remove the NODE now. | |
80 | This is important to do, since we want inliner to know when offline | |
81 | copy of function was removed. */ | |
82 | ||
83 | static bool | |
6c69a029 | 84 | can_remove_node_now_p_1 (struct cgraph_node *node) |
a5b1779f JH |
85 | { |
86 | /* FIXME: When address is taken of DECL_EXTERNAL function we still | |
87 | can remove its offline copy, but we would need to keep unanalyzed node in | |
88 | the callgraph so references can point to it. */ | |
960bfb69 JH |
89 | return (!node->symbol.address_taken |
90 | && !ipa_ref_has_aliases_p (&node->symbol.ref_list) | |
a5b1779f JH |
91 | && cgraph_can_remove_if_no_direct_calls_p (node) |
92 | /* Inlining might enable more devirtualizing, so we want to remove | |
93 | those only after all devirtualizable virtual calls are processed. | |
94 | Lacking may edges in callgraph we just preserve them post | |
95 | inlining. */ | |
960bfb69 JH |
96 | && (!DECL_VIRTUAL_P (node->symbol.decl) |
97 | || (!DECL_COMDAT (node->symbol.decl) | |
98 | && !DECL_EXTERNAL (node->symbol.decl))) | |
a5b1779f JH |
99 | /* During early inlining some unanalyzed cgraph nodes might be in the |
100 | callgraph and they might reffer the function in question. */ | |
101 | && !cgraph_new_nodes); | |
102 | } | |
103 | ||
6c69a029 JH |
104 | /* We are going to eliminate last direct call to NODE (or alias of it) via edge E. |
105 | Verify that the NODE can be removed from unit and if it is contained in comdat | |
106 | group that the whole comdat group is removable. */ | |
107 | ||
108 | static bool | |
109 | can_remove_node_now_p (struct cgraph_node *node, struct cgraph_edge *e) | |
110 | { | |
111 | struct cgraph_node *next; | |
112 | if (!can_remove_node_now_p_1 (node)) | |
113 | return false; | |
114 | ||
115 | /* When we see same comdat group, we need to be sure that all | |
116 | items can be removed. */ | |
960bfb69 | 117 | if (!node->symbol.same_comdat_group) |
6c69a029 | 118 | return true; |
960bfb69 JH |
119 | for (next = cgraph (node->symbol.same_comdat_group); |
120 | next != node; next = cgraph (next->symbol.same_comdat_group)) | |
aa74f081 JH |
121 | if ((next->callers && next->callers != e) |
122 | || !can_remove_node_now_p_1 (next)) | |
6c69a029 JH |
123 | return false; |
124 | return true; | |
125 | } | |
126 | ||
fee8b6da JH |
127 | |
128 | /* E is expected to be an edge being inlined. Clone destination node of | |
129 | the edge and redirect it to the new clone. | |
130 | DUPLICATE is used for bookkeeping on whether we are actually creating new | |
131 | clones or re-using node originally representing out-of-line function call. | |
132 | */ | |
133 | ||
134 | void | |
135 | clone_inlined_nodes (struct cgraph_edge *e, bool duplicate, | |
136 | bool update_original, int *overall_size) | |
137 | { | |
fee8b6da JH |
138 | if (duplicate) |
139 | { | |
140 | /* We may eliminate the need for out-of-line copy to be output. | |
141 | In that case just go ahead and re-use it. This is not just an | |
142 | memory optimization. Making offline copy of fuction disappear | |
143 | from the program will improve future decisions on inlining. */ | |
144 | if (!e->callee->callers->next_caller | |
145 | /* Recursive inlining never wants the master clone to | |
146 | be overwritten. */ | |
147 | && update_original | |
6c69a029 | 148 | && can_remove_node_now_p (e->callee, e)) |
fee8b6da | 149 | { |
6c69a029 JH |
150 | /* TODO: When callee is in a comdat group, we could remove all of it, |
151 | including all inline clones inlined into it. That would however | |
152 | need small function inlining to register edge removal hook to | |
153 | maintain the priority queue. | |
154 | ||
155 | For now we keep the ohter functions in the group in program until | |
156 | cgraph_remove_unreachable_functions gets rid of them. */ | |
fee8b6da | 157 | gcc_assert (!e->callee->global.inlined_to); |
65d630d4 | 158 | symtab_dissolve_same_comdat_group_list ((symtab_node) e->callee); |
960bfb69 | 159 | if (e->callee->analyzed && !DECL_EXTERNAL (e->callee->symbol.decl)) |
fee8b6da JH |
160 | { |
161 | if (overall_size) | |
162 | *overall_size -= inline_summary (e->callee)->size; | |
163 | nfunctions_inlined++; | |
164 | } | |
165 | duplicate = false; | |
960bfb69 | 166 | e->callee->symbol.externally_visible = false; |
898b8927 | 167 | update_noncloned_frequencies (e->callee, e->frequency); |
fee8b6da JH |
168 | } |
169 | else | |
170 | { | |
171 | struct cgraph_node *n; | |
960bfb69 | 172 | n = cgraph_clone_node (e->callee, e->callee->symbol.decl, |
898b8927 | 173 | e->count, e->frequency, |
74605a11 | 174 | update_original, NULL, true); |
fee8b6da JH |
175 | cgraph_redirect_edge_callee (e, n); |
176 | } | |
177 | } | |
65d630d4 JH |
178 | else |
179 | symtab_dissolve_same_comdat_group_list ((symtab_node) e->callee); | |
fee8b6da | 180 | |
fee8b6da JH |
181 | if (e->caller->global.inlined_to) |
182 | e->callee->global.inlined_to = e->caller->global.inlined_to; | |
183 | else | |
184 | e->callee->global.inlined_to = e->caller; | |
fee8b6da JH |
185 | |
186 | /* Recursively clone all bodies. */ | |
187 | for (e = e->callee->callees; e; e = e->next_callee) | |
188 | if (!e->inline_failed) | |
189 | clone_inlined_nodes (e, duplicate, update_original, overall_size); | |
190 | } | |
191 | ||
192 | ||
193 | /* Mark edge E as inlined and update callgraph accordingly. UPDATE_ORIGINAL | |
194 | specify whether profile of original function should be updated. If any new | |
195 | indirect edges are discovered in the process, add them to NEW_EDGES, unless | |
c170d40f JH |
196 | it is NULL. If UPDATE_OVERALL_SUMMARY is false, do not bother to recompute overall |
197 | size of caller after inlining. Caller is required to eventually do it via | |
198 | inline_update_overall_summary. | |
199 | ||
200 | Return true iff any new callgraph edges were discovered as a | |
fee8b6da JH |
201 | result of inlining. */ |
202 | ||
203 | bool | |
204 | inline_call (struct cgraph_edge *e, bool update_original, | |
205 | VEC (cgraph_edge_p, heap) **new_edges, | |
c170d40f | 206 | int *overall_size, bool update_overall_summary) |
fee8b6da JH |
207 | { |
208 | int old_size = 0, new_size = 0; | |
209 | struct cgraph_node *to = NULL; | |
210 | struct cgraph_edge *curr = e; | |
a5b1779f | 211 | struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL); |
fee8b6da JH |
212 | |
213 | /* Don't inline inlined edges. */ | |
214 | gcc_assert (e->inline_failed); | |
215 | /* Don't even think of inlining inline clone. */ | |
a5b1779f | 216 | gcc_assert (!callee->global.inlined_to); |
fee8b6da JH |
217 | |
218 | e->inline_failed = CIF_OK; | |
960bfb69 | 219 | DECL_POSSIBLY_INLINED (callee->symbol.decl) = true; |
fee8b6da | 220 | |
632b4f8e JH |
221 | to = e->caller; |
222 | if (to->global.inlined_to) | |
223 | to = to->global.inlined_to; | |
632b4f8e | 224 | |
a5b1779f JH |
225 | /* If aliases are involved, redirect edge to the actual destination and |
226 | possibly remove the aliases. */ | |
227 | if (e->callee != callee) | |
39e2db00 JH |
228 | { |
229 | struct cgraph_node *alias = e->callee, *next_alias; | |
230 | cgraph_redirect_edge_callee (e, callee); | |
231 | while (alias && alias != callee) | |
232 | { | |
233 | if (!alias->callers | |
6c69a029 | 234 | && can_remove_node_now_p (alias, e)) |
39e2db00 JH |
235 | { |
236 | next_alias = cgraph_alias_aliased_node (alias); | |
237 | cgraph_remove_node (alias); | |
238 | alias = next_alias; | |
239 | } | |
240 | else | |
241 | break; | |
242 | } | |
243 | } | |
a5b1779f | 244 | |
fee8b6da JH |
245 | clone_inlined_nodes (e, true, update_original, overall_size); |
246 | ||
fee8b6da | 247 | gcc_assert (curr->callee->global.inlined_to == to); |
898b8927 JH |
248 | |
249 | old_size = inline_summary (to)->size; | |
250 | inline_merge_summary (e); | |
c170d40f JH |
251 | if (update_overall_summary) |
252 | inline_update_overall_summary (to); | |
898b8927 | 253 | new_size = inline_summary (to)->size; |
b4c0a884 | 254 | if (overall_size) |
fee8b6da JH |
255 | *overall_size += new_size - old_size; |
256 | ncalls_inlined++; | |
257 | ||
25837a2f JH |
258 | /* This must happen after inline_merge_summary that rely on jump |
259 | functions of callee to not be updated. */ | |
5ee53a06 | 260 | if (optimize) |
fee8b6da JH |
261 | return ipa_propagate_indirect_call_infos (curr, new_edges); |
262 | else | |
263 | return false; | |
264 | } | |
265 | ||
266 | ||
267 | /* Copy function body of NODE and redirect all inline clones to it. | |
268 | This is done before inline plan is applied to NODE when there are | |
269 | still some inline clones if it. | |
270 | ||
073a8998 | 271 | This is necessary because inline decisions are not really transitive |
fee8b6da JH |
272 | and the other inline clones may have different bodies. */ |
273 | ||
274 | static struct cgraph_node * | |
275 | save_inline_function_body (struct cgraph_node *node) | |
276 | { | |
277 | struct cgraph_node *first_clone, *n; | |
278 | ||
279 | if (dump_file) | |
280 | fprintf (dump_file, "\nSaving body of %s for later reuse\n", | |
281 | cgraph_node_name (node)); | |
282 | ||
960bfb69 | 283 | gcc_assert (node == cgraph_get_node (node->symbol.decl)); |
fee8b6da JH |
284 | |
285 | /* first_clone will be turned into real function. */ | |
286 | first_clone = node->clones; | |
960bfb69 | 287 | first_clone->symbol.decl = copy_node (node->symbol.decl); |
1ab24192 | 288 | symtab_insert_node_to_hashtable ((symtab_node) first_clone); |
960bfb69 | 289 | gcc_assert (first_clone == cgraph_get_node (first_clone->symbol.decl)); |
fee8b6da JH |
290 | |
291 | /* Now reshape the clone tree, so all other clones descends from | |
292 | first_clone. */ | |
293 | if (first_clone->next_sibling_clone) | |
294 | { | |
295 | for (n = first_clone->next_sibling_clone; n->next_sibling_clone; n = n->next_sibling_clone) | |
296 | n->clone_of = first_clone; | |
297 | n->clone_of = first_clone; | |
298 | n->next_sibling_clone = first_clone->clones; | |
299 | if (first_clone->clones) | |
300 | first_clone->clones->prev_sibling_clone = n; | |
301 | first_clone->clones = first_clone->next_sibling_clone; | |
302 | first_clone->next_sibling_clone->prev_sibling_clone = NULL; | |
303 | first_clone->next_sibling_clone = NULL; | |
304 | gcc_assert (!first_clone->prev_sibling_clone); | |
305 | } | |
306 | first_clone->clone_of = NULL; | |
307 | ||
308 | /* Now node in question has no clones. */ | |
309 | node->clones = NULL; | |
310 | ||
1a3118e9 JH |
311 | /* Inline clones share decl with the function they are cloned |
312 | from. Walk the whole clone tree and redirect them all to the | |
313 | new decl. */ | |
fee8b6da JH |
314 | if (first_clone->clones) |
315 | for (n = first_clone->clones; n != first_clone;) | |
316 | { | |
960bfb69 JH |
317 | gcc_assert (n->symbol.decl == node->symbol.decl); |
318 | n->symbol.decl = first_clone->symbol.decl; | |
fee8b6da JH |
319 | if (n->clones) |
320 | n = n->clones; | |
321 | else if (n->next_sibling_clone) | |
322 | n = n->next_sibling_clone; | |
323 | else | |
324 | { | |
325 | while (n != first_clone && !n->next_sibling_clone) | |
326 | n = n->clone_of; | |
327 | if (n != first_clone) | |
328 | n = n->next_sibling_clone; | |
329 | } | |
330 | } | |
331 | ||
332 | /* Copy the OLD_VERSION_NODE function tree to the new version. */ | |
960bfb69 JH |
333 | tree_function_versioning (node->symbol.decl, first_clone->symbol.decl, |
334 | NULL, true, NULL, false, NULL, NULL); | |
fee8b6da | 335 | |
1a3118e9 JH |
336 | /* The function will be short lived and removed after we inline all the clones, |
337 | but make it internal so we won't confuse ourself. */ | |
960bfb69 JH |
338 | DECL_EXTERNAL (first_clone->symbol.decl) = 0; |
339 | DECL_COMDAT_GROUP (first_clone->symbol.decl) = NULL_TREE; | |
340 | TREE_PUBLIC (first_clone->symbol.decl) = 0; | |
341 | DECL_COMDAT (first_clone->symbol.decl) = 0; | |
fee8b6da JH |
342 | VEC_free (ipa_opt_pass, heap, |
343 | first_clone->ipa_transforms_to_apply); | |
344 | first_clone->ipa_transforms_to_apply = NULL; | |
345 | ||
b4e93f45 JH |
346 | /* When doing recursive inlining, the clone may become unnecessary. |
347 | This is possible i.e. in the case when the recursive function is proved to be | |
348 | non-throwing and the recursion happens only in the EH landing pad. | |
349 | We can not remove the clone until we are done with saving the body. | |
350 | Remove it now. */ | |
351 | if (!first_clone->callers) | |
352 | { | |
353 | cgraph_remove_node_and_inline_clones (first_clone, NULL); | |
354 | first_clone = NULL; | |
355 | } | |
fee8b6da | 356 | #ifdef ENABLE_CHECKING |
b4e93f45 JH |
357 | else |
358 | verify_cgraph_node (first_clone); | |
fee8b6da JH |
359 | #endif |
360 | return first_clone; | |
361 | } | |
362 | ||
9c8305f8 JH |
363 | /* Return true when function body of DECL still needs to be kept around |
364 | for later re-use. */ | |
65d630d4 | 365 | static bool |
9c8305f8 JH |
366 | preserve_function_body_p (struct cgraph_node *node) |
367 | { | |
368 | gcc_assert (cgraph_global_info_ready); | |
369 | gcc_assert (!node->alias && !node->thunk.thunk_p); | |
370 | ||
371 | /* Look if there is any clone around. */ | |
372 | if (node->clones) | |
373 | return true; | |
374 | return false; | |
375 | } | |
fee8b6da JH |
376 | |
377 | /* Apply inline plan to function. */ | |
378 | ||
379 | unsigned int | |
380 | inline_transform (struct cgraph_node *node) | |
381 | { | |
382 | unsigned int todo = 0; | |
383 | struct cgraph_edge *e; | |
c9fc06dc | 384 | |
fee8b6da JH |
385 | /* FIXME: Currently the pass manager is adding inline transform more than |
386 | once to some clones. This needs revisiting after WPA cleanups. */ | |
387 | if (cfun->after_inlining) | |
388 | return 0; | |
389 | ||
390 | /* We might need the body of this function so that we can expand | |
391 | it inline somewhere else. */ | |
9c8305f8 | 392 | if (preserve_function_body_p (node)) |
fee8b6da JH |
393 | save_inline_function_body (node); |
394 | ||
395 | for (e = node->callees; e; e = e->next_callee) | |
c9fc06dc CB |
396 | cgraph_redirect_edge_call_stmt_to_callee (e); |
397 | ||
398 | timevar_push (TV_INTEGRATION); | |
399 | if (node->callees) | |
55f01229 | 400 | todo = optimize_inline_calls (current_function_decl); |
c9fc06dc CB |
401 | timevar_pop (TV_INTEGRATION); |
402 | ||
f8698b37 RG |
403 | cfun->always_inline_functions_inlined = true; |
404 | cfun->after_inlining = true; | |
405 | todo |= execute_fixup_cfg (); | |
406 | ||
55f01229 RG |
407 | if (!(todo & TODO_update_ssa_any)) |
408 | /* Redirecting edges might lead to a need for vops to be recomputed. */ | |
409 | todo |= TODO_update_ssa_only_virtuals; | |
410 | ||
f8698b37 | 411 | return todo; |
fee8b6da | 412 | } |