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9d30f3c1 | 1 | /* Pass computing data for optimizing stdarg functions. |
bad25453 | 2 | Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010, 2011 |
cf835838 | 3 | Free Software Foundation, Inc. |
9d30f3c1 JJ |
4 | Contributed by Jakub Jelinek <jakub@redhat.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
9dcd6f09 | 10 | the Free Software Foundation; either version 3, or (at your option) |
9d30f3c1 JJ |
11 | any later version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
9d30f3c1 JJ |
21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "function.h" | |
28 | #include "langhooks.h" | |
cf835838 | 29 | #include "gimple-pretty-print.h" |
9d30f3c1 JJ |
30 | #include "target.h" |
31 | #include "tree-flow.h" | |
32 | #include "tree-pass.h" | |
33 | #include "tree-stdarg.h" | |
34 | ||
35 | /* A simple pass that attempts to optimize stdarg functions on architectures | |
36 | that need to save register arguments to stack on entry to stdarg functions. | |
37 | If the function doesn't use any va_start macros, no registers need to | |
38 | be saved. If va_start macros are used, the va_list variables don't escape | |
39 | the function, it is only necessary to save registers that will be used | |
40 | in va_arg macros. E.g. if va_arg is only used with integral types | |
41 | in the function, floating point registers don't need to be saved, etc. */ | |
42 | ||
43 | ||
44 | /* Return true if basic block VA_ARG_BB is dominated by VA_START_BB and | |
45 | is executed at most as many times as VA_START_BB. */ | |
46 | ||
47 | static bool | |
48 | reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb) | |
49 | { | |
134c2de3 JJ |
50 | VEC (edge, heap) *stack = NULL; |
51 | edge e; | |
9d30f3c1 | 52 | edge_iterator ei; |
9d30f3c1 JJ |
53 | sbitmap visited; |
54 | bool ret; | |
55 | ||
56 | if (va_arg_bb == va_start_bb) | |
57 | return true; | |
58 | ||
59 | if (! dominated_by_p (CDI_DOMINATORS, va_arg_bb, va_start_bb)) | |
60 | return false; | |
61 | ||
9d30f3c1 | 62 | visited = sbitmap_alloc (last_basic_block); |
f61e445a | 63 | bitmap_clear (visited); |
9d30f3c1 JJ |
64 | ret = true; |
65 | ||
66 | FOR_EACH_EDGE (e, ei, va_arg_bb->preds) | |
134c2de3 | 67 | VEC_safe_push (edge, heap, stack, e); |
9d30f3c1 | 68 | |
134c2de3 | 69 | while (! VEC_empty (edge, stack)) |
9d30f3c1 JJ |
70 | { |
71 | basic_block src; | |
72 | ||
134c2de3 | 73 | e = VEC_pop (edge, stack); |
9d30f3c1 JJ |
74 | src = e->src; |
75 | ||
76 | if (e->flags & EDGE_COMPLEX) | |
77 | { | |
78 | ret = false; | |
79 | break; | |
80 | } | |
81 | ||
82 | if (src == va_start_bb) | |
83 | continue; | |
84 | ||
85 | /* va_arg_bb can be executed more times than va_start_bb. */ | |
86 | if (src == va_arg_bb) | |
87 | { | |
88 | ret = false; | |
89 | break; | |
90 | } | |
91 | ||
92 | gcc_assert (src != ENTRY_BLOCK_PTR); | |
93 | ||
94 | if (! TEST_BIT (visited, src->index)) | |
95 | { | |
96 | SET_BIT (visited, src->index); | |
97 | FOR_EACH_EDGE (e, ei, src->preds) | |
134c2de3 | 98 | VEC_safe_push (edge, heap, stack, e); |
9d30f3c1 JJ |
99 | } |
100 | } | |
101 | ||
134c2de3 | 102 | VEC_free (edge, heap, stack); |
9d30f3c1 JJ |
103 | sbitmap_free (visited); |
104 | return ret; | |
105 | } | |
106 | ||
107 | ||
108 | /* For statement COUNTER = RHS, if RHS is COUNTER + constant, | |
109 | return constant, otherwise return (unsigned HOST_WIDE_INT) -1. | |
110 | GPR_P is true if this is GPR counter. */ | |
111 | ||
112 | static unsigned HOST_WIDE_INT | |
113 | va_list_counter_bump (struct stdarg_info *si, tree counter, tree rhs, | |
114 | bool gpr_p) | |
115 | { | |
726a989a RB |
116 | tree lhs, orig_lhs; |
117 | gimple stmt; | |
9d30f3c1 JJ |
118 | unsigned HOST_WIDE_INT ret = 0, val, counter_val; |
119 | unsigned int max_size; | |
120 | ||
121 | if (si->offsets == NULL) | |
122 | { | |
123 | unsigned int i; | |
124 | ||
5ed6ace5 | 125 | si->offsets = XNEWVEC (int, num_ssa_names); |
9d30f3c1 JJ |
126 | for (i = 0; i < num_ssa_names; ++i) |
127 | si->offsets[i] = -1; | |
128 | } | |
129 | ||
130 | counter_val = gpr_p ? cfun->va_list_gpr_size : cfun->va_list_fpr_size; | |
131 | max_size = gpr_p ? VA_LIST_MAX_GPR_SIZE : VA_LIST_MAX_FPR_SIZE; | |
132 | orig_lhs = lhs = rhs; | |
133 | while (lhs) | |
134 | { | |
726a989a | 135 | enum tree_code rhs_code; |
58da96fe | 136 | tree rhs1; |
726a989a | 137 | |
9d30f3c1 JJ |
138 | if (si->offsets[SSA_NAME_VERSION (lhs)] != -1) |
139 | { | |
140 | if (counter_val >= max_size) | |
141 | { | |
142 | ret = max_size; | |
143 | break; | |
144 | } | |
145 | ||
146 | ret -= counter_val - si->offsets[SSA_NAME_VERSION (lhs)]; | |
147 | break; | |
148 | } | |
149 | ||
150 | stmt = SSA_NAME_DEF_STMT (lhs); | |
151 | ||
726a989a | 152 | if (!is_gimple_assign (stmt) || gimple_assign_lhs (stmt) != lhs) |
9d30f3c1 JJ |
153 | return (unsigned HOST_WIDE_INT) -1; |
154 | ||
726a989a | 155 | rhs_code = gimple_assign_rhs_code (stmt); |
58da96fe | 156 | rhs1 = gimple_assign_rhs1 (stmt); |
726a989a RB |
157 | if ((get_gimple_rhs_class (rhs_code) == GIMPLE_SINGLE_RHS |
158 | || gimple_assign_cast_p (stmt)) | |
58da96fe | 159 | && TREE_CODE (rhs1) == SSA_NAME) |
9d30f3c1 | 160 | { |
58da96fe | 161 | lhs = rhs1; |
9d30f3c1 JJ |
162 | continue; |
163 | } | |
164 | ||
726a989a RB |
165 | if ((rhs_code == POINTER_PLUS_EXPR |
166 | || rhs_code == PLUS_EXPR) | |
58da96fe | 167 | && TREE_CODE (rhs1) == SSA_NAME |
726a989a | 168 | && host_integerp (gimple_assign_rhs2 (stmt), 1)) |
9d30f3c1 | 169 | { |
726a989a | 170 | ret += tree_low_cst (gimple_assign_rhs2 (stmt), 1); |
58da96fe RG |
171 | lhs = rhs1; |
172 | continue; | |
173 | } | |
174 | ||
175 | if (rhs_code == ADDR_EXPR | |
176 | && TREE_CODE (TREE_OPERAND (rhs1, 0)) == MEM_REF | |
177 | && TREE_CODE (TREE_OPERAND (TREE_OPERAND (rhs1, 0), 0)) == SSA_NAME | |
178 | && host_integerp (TREE_OPERAND (TREE_OPERAND (rhs1, 0), 1), 1)) | |
179 | { | |
180 | ret += tree_low_cst (TREE_OPERAND (TREE_OPERAND (rhs1, 0), 1), 1); | |
181 | lhs = TREE_OPERAND (TREE_OPERAND (rhs1, 0), 0); | |
9d30f3c1 JJ |
182 | continue; |
183 | } | |
184 | ||
726a989a RB |
185 | if (get_gimple_rhs_class (rhs_code) != GIMPLE_SINGLE_RHS) |
186 | return (unsigned HOST_WIDE_INT) -1; | |
9d30f3c1 | 187 | |
726a989a | 188 | rhs = gimple_assign_rhs1 (stmt); |
9d30f3c1 JJ |
189 | if (TREE_CODE (counter) != TREE_CODE (rhs)) |
190 | return (unsigned HOST_WIDE_INT) -1; | |
191 | ||
192 | if (TREE_CODE (counter) == COMPONENT_REF) | |
193 | { | |
194 | if (get_base_address (counter) != get_base_address (rhs) | |
195 | || TREE_CODE (TREE_OPERAND (rhs, 1)) != FIELD_DECL | |
196 | || TREE_OPERAND (counter, 1) != TREE_OPERAND (rhs, 1)) | |
197 | return (unsigned HOST_WIDE_INT) -1; | |
198 | } | |
199 | else if (counter != rhs) | |
200 | return (unsigned HOST_WIDE_INT) -1; | |
201 | ||
202 | lhs = NULL; | |
203 | } | |
204 | ||
205 | lhs = orig_lhs; | |
206 | val = ret + counter_val; | |
207 | while (lhs) | |
208 | { | |
726a989a | 209 | enum tree_code rhs_code; |
58da96fe | 210 | tree rhs1; |
726a989a | 211 | |
9d30f3c1 JJ |
212 | if (si->offsets[SSA_NAME_VERSION (lhs)] != -1) |
213 | break; | |
214 | ||
215 | if (val >= max_size) | |
216 | si->offsets[SSA_NAME_VERSION (lhs)] = max_size; | |
217 | else | |
218 | si->offsets[SSA_NAME_VERSION (lhs)] = val; | |
219 | ||
220 | stmt = SSA_NAME_DEF_STMT (lhs); | |
221 | ||
726a989a | 222 | rhs_code = gimple_assign_rhs_code (stmt); |
58da96fe | 223 | rhs1 = gimple_assign_rhs1 (stmt); |
726a989a RB |
224 | if ((get_gimple_rhs_class (rhs_code) == GIMPLE_SINGLE_RHS |
225 | || gimple_assign_cast_p (stmt)) | |
58da96fe | 226 | && TREE_CODE (rhs1) == SSA_NAME) |
9d30f3c1 | 227 | { |
58da96fe | 228 | lhs = rhs1; |
9d30f3c1 JJ |
229 | continue; |
230 | } | |
231 | ||
726a989a RB |
232 | if ((rhs_code == POINTER_PLUS_EXPR |
233 | || rhs_code == PLUS_EXPR) | |
58da96fe | 234 | && TREE_CODE (rhs1) == SSA_NAME |
726a989a | 235 | && host_integerp (gimple_assign_rhs2 (stmt), 1)) |
9d30f3c1 | 236 | { |
726a989a | 237 | val -= tree_low_cst (gimple_assign_rhs2 (stmt), 1); |
58da96fe RG |
238 | lhs = rhs1; |
239 | continue; | |
240 | } | |
241 | ||
242 | if (rhs_code == ADDR_EXPR | |
243 | && TREE_CODE (TREE_OPERAND (rhs1, 0)) == MEM_REF | |
244 | && TREE_CODE (TREE_OPERAND (TREE_OPERAND (rhs1, 0), 0)) == SSA_NAME | |
245 | && host_integerp (TREE_OPERAND (TREE_OPERAND (rhs1, 0), 1), 1)) | |
246 | { | |
247 | val -= tree_low_cst (TREE_OPERAND (TREE_OPERAND (rhs1, 0), 1), 1); | |
248 | lhs = TREE_OPERAND (TREE_OPERAND (rhs1, 0), 0); | |
9d30f3c1 JJ |
249 | continue; |
250 | } | |
251 | ||
252 | lhs = NULL; | |
253 | } | |
254 | ||
255 | return ret; | |
256 | } | |
257 | ||
258 | ||
259 | /* Called by walk_tree to look for references to va_list variables. */ | |
260 | ||
261 | static tree | |
262 | find_va_list_reference (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED, | |
263 | void *data) | |
264 | { | |
726a989a | 265 | bitmap va_list_vars = (bitmap) ((struct walk_stmt_info *) data)->info; |
9d30f3c1 JJ |
266 | tree var = *tp; |
267 | ||
268 | if (TREE_CODE (var) == SSA_NAME) | |
6b4a85ad RG |
269 | { |
270 | if (bitmap_bit_p (va_list_vars, SSA_NAME_VERSION (var))) | |
271 | return var; | |
272 | } | |
273 | else if (TREE_CODE (var) == VAR_DECL) | |
274 | { | |
275 | if (bitmap_bit_p (va_list_vars, DECL_UID (var) + num_ssa_names)) | |
276 | return var; | |
277 | } | |
9d30f3c1 JJ |
278 | |
279 | return NULL_TREE; | |
280 | } | |
281 | ||
282 | ||
283 | /* Helper function of va_list_counter_struct_op. Compute | |
284 | cfun->va_list_{g,f}pr_size. AP is a va_list GPR/FPR counter, | |
285 | if WRITE_P is true, seen in AP = VAR, otherwise seen in VAR = AP | |
286 | statement. GPR_P is true if AP is a GPR counter, false if it is | |
287 | a FPR counter. */ | |
288 | ||
289 | static void | |
290 | va_list_counter_op (struct stdarg_info *si, tree ap, tree var, bool gpr_p, | |
291 | bool write_p) | |
292 | { | |
293 | unsigned HOST_WIDE_INT increment; | |
294 | ||
295 | if (si->compute_sizes < 0) | |
296 | { | |
297 | si->compute_sizes = 0; | |
298 | if (si->va_start_count == 1 | |
299 | && reachable_at_most_once (si->bb, si->va_start_bb)) | |
300 | si->compute_sizes = 1; | |
301 | ||
302 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
303 | fprintf (dump_file, | |
304 | "bb%d will %sbe executed at most once for each va_start " | |
305 | "in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ", | |
306 | si->va_start_bb->index); | |
307 | } | |
308 | ||
309 | if (write_p | |
310 | && si->compute_sizes | |
311 | && (increment = va_list_counter_bump (si, ap, var, gpr_p)) + 1 > 1) | |
312 | { | |
313 | if (gpr_p && cfun->va_list_gpr_size + increment < VA_LIST_MAX_GPR_SIZE) | |
314 | { | |
315 | cfun->va_list_gpr_size += increment; | |
316 | return; | |
317 | } | |
318 | ||
319 | if (!gpr_p && cfun->va_list_fpr_size + increment < VA_LIST_MAX_FPR_SIZE) | |
320 | { | |
321 | cfun->va_list_fpr_size += increment; | |
322 | return; | |
323 | } | |
324 | } | |
325 | ||
326 | if (write_p || !si->compute_sizes) | |
327 | { | |
328 | if (gpr_p) | |
329 | cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE; | |
330 | else | |
331 | cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE; | |
332 | } | |
333 | } | |
334 | ||
335 | ||
336 | /* If AP is a va_list GPR/FPR counter, compute cfun->va_list_{g,f}pr_size. | |
337 | If WRITE_P is true, AP has been seen in AP = VAR assignment, if WRITE_P | |
338 | is false, AP has been seen in VAR = AP assignment. | |
339 | Return true if the AP = VAR (resp. VAR = AP) statement is a recognized | |
340 | va_arg operation that doesn't cause the va_list variable to escape | |
341 | current function. */ | |
342 | ||
343 | static bool | |
344 | va_list_counter_struct_op (struct stdarg_info *si, tree ap, tree var, | |
345 | bool write_p) | |
346 | { | |
347 | tree base; | |
348 | ||
349 | if (TREE_CODE (ap) != COMPONENT_REF | |
350 | || TREE_CODE (TREE_OPERAND (ap, 1)) != FIELD_DECL) | |
351 | return false; | |
352 | ||
353 | if (TREE_CODE (var) != SSA_NAME | |
6b4a85ad | 354 | || bitmap_bit_p (si->va_list_vars, SSA_NAME_VERSION (var))) |
9d30f3c1 JJ |
355 | return false; |
356 | ||
357 | base = get_base_address (ap); | |
358 | if (TREE_CODE (base) != VAR_DECL | |
6b4a85ad | 359 | || !bitmap_bit_p (si->va_list_vars, DECL_UID (base) + num_ssa_names)) |
9d30f3c1 JJ |
360 | return false; |
361 | ||
362 | if (TREE_OPERAND (ap, 1) == va_list_gpr_counter_field) | |
363 | va_list_counter_op (si, ap, var, true, write_p); | |
364 | else if (TREE_OPERAND (ap, 1) == va_list_fpr_counter_field) | |
365 | va_list_counter_op (si, ap, var, false, write_p); | |
366 | ||
367 | return true; | |
368 | } | |
369 | ||
370 | ||
371 | /* Check for TEM = AP. Return true if found and the caller shouldn't | |
372 | search for va_list references in the statement. */ | |
373 | ||
374 | static bool | |
375 | va_list_ptr_read (struct stdarg_info *si, tree ap, tree tem) | |
376 | { | |
377 | if (TREE_CODE (ap) != VAR_DECL | |
6b4a85ad | 378 | || !bitmap_bit_p (si->va_list_vars, DECL_UID (ap) + num_ssa_names)) |
9d30f3c1 JJ |
379 | return false; |
380 | ||
381 | if (TREE_CODE (tem) != SSA_NAME | |
6b4a85ad | 382 | || bitmap_bit_p (si->va_list_vars, SSA_NAME_VERSION (tem))) |
9d30f3c1 JJ |
383 | return false; |
384 | ||
385 | if (si->compute_sizes < 0) | |
386 | { | |
387 | si->compute_sizes = 0; | |
388 | if (si->va_start_count == 1 | |
389 | && reachable_at_most_once (si->bb, si->va_start_bb)) | |
390 | si->compute_sizes = 1; | |
391 | ||
392 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
393 | fprintf (dump_file, | |
394 | "bb%d will %sbe executed at most once for each va_start " | |
395 | "in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ", | |
396 | si->va_start_bb->index); | |
397 | } | |
398 | ||
399 | /* For void * or char * va_list types, there is just one counter. | |
400 | If va_arg is used in a loop, we don't know how many registers need | |
401 | saving. */ | |
402 | if (! si->compute_sizes) | |
403 | return false; | |
404 | ||
405 | if (va_list_counter_bump (si, ap, tem, true) == (unsigned HOST_WIDE_INT) -1) | |
406 | return false; | |
407 | ||
408 | /* Note the temporary, as we need to track whether it doesn't escape | |
409 | the current function. */ | |
6b4a85ad RG |
410 | bitmap_set_bit (si->va_list_escape_vars, SSA_NAME_VERSION (tem)); |
411 | ||
9d30f3c1 JJ |
412 | return true; |
413 | } | |
414 | ||
415 | ||
416 | /* Check for: | |
417 | tem1 = AP; | |
418 | TEM2 = tem1 + CST; | |
419 | AP = TEM2; | |
420 | sequence and update cfun->va_list_gpr_size. Return true if found. */ | |
421 | ||
422 | static bool | |
423 | va_list_ptr_write (struct stdarg_info *si, tree ap, tree tem2) | |
424 | { | |
425 | unsigned HOST_WIDE_INT increment; | |
426 | ||
427 | if (TREE_CODE (ap) != VAR_DECL | |
6b4a85ad | 428 | || !bitmap_bit_p (si->va_list_vars, DECL_UID (ap) + num_ssa_names)) |
9d30f3c1 JJ |
429 | return false; |
430 | ||
431 | if (TREE_CODE (tem2) != SSA_NAME | |
6b4a85ad | 432 | || bitmap_bit_p (si->va_list_vars, SSA_NAME_VERSION (tem2))) |
9d30f3c1 JJ |
433 | return false; |
434 | ||
435 | if (si->compute_sizes <= 0) | |
436 | return false; | |
437 | ||
438 | increment = va_list_counter_bump (si, ap, tem2, true); | |
439 | if (increment + 1 <= 1) | |
440 | return false; | |
441 | ||
442 | if (cfun->va_list_gpr_size + increment < VA_LIST_MAX_GPR_SIZE) | |
443 | cfun->va_list_gpr_size += increment; | |
444 | else | |
445 | cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE; | |
446 | ||
447 | return true; | |
448 | } | |
449 | ||
450 | ||
451 | /* If RHS is X, (some type *) X or X + CST for X a temporary variable | |
452 | containing value of some va_list variable plus optionally some constant, | |
453 | either set si->va_list_escapes or add LHS to si->va_list_escape_vars, | |
454 | depending whether LHS is a function local temporary. */ | |
455 | ||
456 | static void | |
457 | check_va_list_escapes (struct stdarg_info *si, tree lhs, tree rhs) | |
458 | { | |
459 | if (! POINTER_TYPE_P (TREE_TYPE (rhs))) | |
460 | return; | |
461 | ||
58da96fe RG |
462 | if (TREE_CODE (rhs) == SSA_NAME) |
463 | { | |
6b4a85ad | 464 | if (! bitmap_bit_p (si->va_list_escape_vars, SSA_NAME_VERSION (rhs))) |
58da96fe RG |
465 | return; |
466 | } | |
467 | else if (TREE_CODE (rhs) == ADDR_EXPR | |
468 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF | |
469 | && TREE_CODE (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0)) == SSA_NAME) | |
470 | { | |
6b4a85ad RG |
471 | tree ptr = TREE_OPERAND (TREE_OPERAND (rhs, 0), 0); |
472 | if (! bitmap_bit_p (si->va_list_escape_vars, SSA_NAME_VERSION (ptr))) | |
58da96fe RG |
473 | return; |
474 | } | |
475 | else | |
9d30f3c1 JJ |
476 | return; |
477 | ||
6b4a85ad | 478 | if (TREE_CODE (lhs) != SSA_NAME) |
9d30f3c1 JJ |
479 | { |
480 | si->va_list_escapes = true; | |
481 | return; | |
482 | } | |
483 | ||
484 | if (si->compute_sizes < 0) | |
485 | { | |
486 | si->compute_sizes = 0; | |
487 | if (si->va_start_count == 1 | |
488 | && reachable_at_most_once (si->bb, si->va_start_bb)) | |
489 | si->compute_sizes = 1; | |
490 | ||
491 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
492 | fprintf (dump_file, | |
493 | "bb%d will %sbe executed at most once for each va_start " | |
494 | "in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ", | |
495 | si->va_start_bb->index); | |
496 | } | |
497 | ||
498 | /* For void * or char * va_list types, there is just one counter. | |
499 | If va_arg is used in a loop, we don't know how many registers need | |
500 | saving. */ | |
501 | if (! si->compute_sizes) | |
502 | { | |
503 | si->va_list_escapes = true; | |
504 | return; | |
505 | } | |
506 | ||
507 | if (va_list_counter_bump (si, si->va_start_ap, lhs, true) | |
508 | == (unsigned HOST_WIDE_INT) -1) | |
509 | { | |
510 | si->va_list_escapes = true; | |
511 | return; | |
512 | } | |
513 | ||
6b4a85ad | 514 | bitmap_set_bit (si->va_list_escape_vars, SSA_NAME_VERSION (lhs)); |
9d30f3c1 JJ |
515 | } |
516 | ||
517 | ||
518 | /* Check all uses of temporaries from si->va_list_escape_vars bitmap. | |
519 | Return true if va_list might be escaping. */ | |
520 | ||
521 | static bool | |
522 | check_all_va_list_escapes (struct stdarg_info *si) | |
523 | { | |
524 | basic_block bb; | |
525 | ||
526 | FOR_EACH_BB (bb) | |
527 | { | |
726a989a | 528 | gimple_stmt_iterator i; |
9d30f3c1 | 529 | |
726a989a | 530 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
9d30f3c1 | 531 | { |
726a989a RB |
532 | gimple stmt = gsi_stmt (i); |
533 | tree use; | |
9d30f3c1 JJ |
534 | ssa_op_iter iter; |
535 | ||
b5b8b0ac AO |
536 | if (is_gimple_debug (stmt)) |
537 | continue; | |
538 | ||
9d30f3c1 JJ |
539 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_ALL_USES) |
540 | { | |
541 | if (! bitmap_bit_p (si->va_list_escape_vars, | |
6b4a85ad | 542 | SSA_NAME_VERSION (use))) |
9d30f3c1 JJ |
543 | continue; |
544 | ||
726a989a | 545 | if (is_gimple_assign (stmt)) |
9d30f3c1 | 546 | { |
726a989a RB |
547 | tree rhs = gimple_assign_rhs1 (stmt); |
548 | enum tree_code rhs_code = gimple_assign_rhs_code (stmt); | |
9d30f3c1 JJ |
549 | |
550 | /* x = *ap_temp; */ | |
58da96fe | 551 | if (rhs_code == MEM_REF |
9d30f3c1 JJ |
552 | && TREE_OPERAND (rhs, 0) == use |
553 | && TYPE_SIZE_UNIT (TREE_TYPE (rhs)) | |
554 | && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (rhs)), 1) | |
555 | && si->offsets[SSA_NAME_VERSION (use)] != -1) | |
556 | { | |
557 | unsigned HOST_WIDE_INT gpr_size; | |
558 | tree access_size = TYPE_SIZE_UNIT (TREE_TYPE (rhs)); | |
559 | ||
560 | gpr_size = si->offsets[SSA_NAME_VERSION (use)] | |
70f34814 | 561 | + tree_low_cst (TREE_OPERAND (rhs, 1), 0) |
9d30f3c1 JJ |
562 | + tree_low_cst (access_size, 1); |
563 | if (gpr_size >= VA_LIST_MAX_GPR_SIZE) | |
564 | cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE; | |
565 | else if (gpr_size > cfun->va_list_gpr_size) | |
566 | cfun->va_list_gpr_size = gpr_size; | |
567 | continue; | |
568 | } | |
569 | ||
570 | /* va_arg sequences may contain | |
571 | other_ap_temp = ap_temp; | |
572 | other_ap_temp = ap_temp + constant; | |
573 | other_ap_temp = (some_type *) ap_temp; | |
574 | ap = ap_temp; | |
575 | statements. */ | |
726a989a RB |
576 | if (rhs == use |
577 | && ((rhs_code == POINTER_PLUS_EXPR | |
578 | && (TREE_CODE (gimple_assign_rhs2 (stmt)) | |
579 | == INTEGER_CST)) | |
580 | || gimple_assign_cast_p (stmt) | |
581 | || (get_gimple_rhs_class (rhs_code) | |
582 | == GIMPLE_SINGLE_RHS))) | |
9d30f3c1 | 583 | { |
726a989a RB |
584 | tree lhs = gimple_assign_lhs (stmt); |
585 | ||
9d30f3c1 JJ |
586 | if (TREE_CODE (lhs) == SSA_NAME |
587 | && bitmap_bit_p (si->va_list_escape_vars, | |
6b4a85ad | 588 | SSA_NAME_VERSION (lhs))) |
9d30f3c1 JJ |
589 | continue; |
590 | ||
591 | if (TREE_CODE (lhs) == VAR_DECL | |
592 | && bitmap_bit_p (si->va_list_vars, | |
6b4a85ad | 593 | DECL_UID (lhs) + num_ssa_names)) |
9d30f3c1 JJ |
594 | continue; |
595 | } | |
58da96fe RG |
596 | else if (rhs_code == ADDR_EXPR |
597 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF | |
598 | && TREE_OPERAND (TREE_OPERAND (rhs, 0), 0) == use) | |
599 | { | |
600 | tree lhs = gimple_assign_lhs (stmt); | |
601 | ||
602 | if (bitmap_bit_p (si->va_list_escape_vars, | |
6b4a85ad | 603 | SSA_NAME_VERSION (lhs))) |
58da96fe RG |
604 | continue; |
605 | } | |
9d30f3c1 JJ |
606 | } |
607 | ||
608 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
609 | { | |
610 | fputs ("va_list escapes in ", dump_file); | |
726a989a | 611 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
9d30f3c1 JJ |
612 | fputc ('\n', dump_file); |
613 | } | |
614 | return true; | |
615 | } | |
616 | } | |
617 | } | |
618 | ||
619 | return false; | |
620 | } | |
621 | ||
622 | ||
623 | /* Return true if this optimization pass should be done. | |
624 | It makes only sense for stdarg functions. */ | |
625 | ||
626 | static bool | |
627 | gate_optimize_stdarg (void) | |
628 | { | |
1f9081d1 XDL |
629 | /* This optimization is only for stdarg functions. */ |
630 | return cfun->stdarg != 0; | |
9d30f3c1 JJ |
631 | } |
632 | ||
633 | ||
634 | /* Entry point to the stdarg optimization pass. */ | |
635 | ||
c2924966 | 636 | static unsigned int |
9d30f3c1 JJ |
637 | execute_optimize_stdarg (void) |
638 | { | |
639 | basic_block bb; | |
640 | bool va_list_escapes = false; | |
641 | bool va_list_simple_ptr; | |
642 | struct stdarg_info si; | |
726a989a | 643 | struct walk_stmt_info wi; |
9d30f3c1 | 644 | const char *funcname = NULL; |
35cbb299 | 645 | tree cfun_va_list; |
9d30f3c1 JJ |
646 | |
647 | cfun->va_list_gpr_size = 0; | |
648 | cfun->va_list_fpr_size = 0; | |
649 | memset (&si, 0, sizeof (si)); | |
650 | si.va_list_vars = BITMAP_ALLOC (NULL); | |
651 | si.va_list_escape_vars = BITMAP_ALLOC (NULL); | |
652 | ||
653 | if (dump_file) | |
654 | funcname = lang_hooks.decl_printable_name (current_function_decl, 2); | |
655 | ||
35cbb299 KT |
656 | cfun_va_list = targetm.fn_abi_va_list (cfun->decl); |
657 | va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
658 | && (TREE_TYPE (cfun_va_list) == void_type_node | |
659 | || TREE_TYPE (cfun_va_list) == char_type_node); | |
660 | gcc_assert (is_gimple_reg_type (cfun_va_list) == va_list_simple_ptr); | |
9d30f3c1 JJ |
661 | |
662 | FOR_EACH_BB (bb) | |
663 | { | |
726a989a | 664 | gimple_stmt_iterator i; |
9d30f3c1 | 665 | |
726a989a | 666 | for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) |
9d30f3c1 | 667 | { |
726a989a RB |
668 | gimple stmt = gsi_stmt (i); |
669 | tree callee, ap; | |
9d30f3c1 | 670 | |
726a989a | 671 | if (!is_gimple_call (stmt)) |
9d30f3c1 JJ |
672 | continue; |
673 | ||
726a989a | 674 | callee = gimple_call_fndecl (stmt); |
9d30f3c1 JJ |
675 | if (!callee |
676 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
677 | continue; | |
678 | ||
679 | switch (DECL_FUNCTION_CODE (callee)) | |
680 | { | |
681 | case BUILT_IN_VA_START: | |
682 | break; | |
683 | /* If old style builtins are used, don't optimize anything. */ | |
684 | case BUILT_IN_SAVEREGS: | |
9d30f3c1 JJ |
685 | case BUILT_IN_NEXT_ARG: |
686 | va_list_escapes = true; | |
687 | continue; | |
688 | default: | |
689 | continue; | |
690 | } | |
691 | ||
692 | si.va_start_count++; | |
726a989a | 693 | ap = gimple_call_arg (stmt, 0); |
bb673b41 RG |
694 | |
695 | if (TREE_CODE (ap) != ADDR_EXPR) | |
9d30f3c1 JJ |
696 | { |
697 | va_list_escapes = true; | |
698 | break; | |
699 | } | |
9d30f3c1 | 700 | ap = TREE_OPERAND (ap, 0); |
bb673b41 RG |
701 | if (TREE_CODE (ap) == ARRAY_REF) |
702 | { | |
703 | if (! integer_zerop (TREE_OPERAND (ap, 1))) | |
704 | { | |
705 | va_list_escapes = true; | |
706 | break; | |
707 | } | |
708 | ap = TREE_OPERAND (ap, 0); | |
709 | } | |
710 | if (TYPE_MAIN_VARIANT (TREE_TYPE (ap)) | |
35cbb299 | 711 | != TYPE_MAIN_VARIANT (targetm.fn_abi_va_list (cfun->decl)) |
bb673b41 RG |
712 | || TREE_CODE (ap) != VAR_DECL) |
713 | { | |
714 | va_list_escapes = true; | |
715 | break; | |
716 | } | |
717 | ||
9d30f3c1 JJ |
718 | if (is_global_var (ap)) |
719 | { | |
720 | va_list_escapes = true; | |
721 | break; | |
722 | } | |
723 | ||
6b4a85ad | 724 | bitmap_set_bit (si.va_list_vars, DECL_UID (ap) + num_ssa_names); |
9d30f3c1 JJ |
725 | |
726 | /* VA_START_BB and VA_START_AP will be only used if there is just | |
727 | one va_start in the function. */ | |
728 | si.va_start_bb = bb; | |
729 | si.va_start_ap = ap; | |
730 | } | |
731 | ||
732 | if (va_list_escapes) | |
733 | break; | |
734 | } | |
735 | ||
736 | /* If there were no va_start uses in the function, there is no need to | |
737 | save anything. */ | |
738 | if (si.va_start_count == 0) | |
739 | goto finish; | |
740 | ||
741 | /* If some va_list arguments weren't local, we can't optimize. */ | |
742 | if (va_list_escapes) | |
743 | goto finish; | |
744 | ||
745 | /* For void * or char * va_list, something useful can be done only | |
746 | if there is just one va_start. */ | |
747 | if (va_list_simple_ptr && si.va_start_count > 1) | |
748 | { | |
749 | va_list_escapes = true; | |
750 | goto finish; | |
751 | } | |
752 | ||
753 | /* For struct * va_list, if the backend didn't tell us what the counter fields | |
754 | are, there is nothing more we can do. */ | |
755 | if (!va_list_simple_ptr | |
756 | && va_list_gpr_counter_field == NULL_TREE | |
757 | && va_list_fpr_counter_field == NULL_TREE) | |
758 | { | |
759 | va_list_escapes = true; | |
760 | goto finish; | |
761 | } | |
762 | ||
763 | /* For void * or char * va_list there is just one counter | |
764 | (va_list itself). Use VA_LIST_GPR_SIZE for it. */ | |
765 | if (va_list_simple_ptr) | |
766 | cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE; | |
767 | ||
18c57f2c | 768 | calculate_dominance_info (CDI_DOMINATORS); |
726a989a RB |
769 | memset (&wi, 0, sizeof (wi)); |
770 | wi.info = si.va_list_vars; | |
18c57f2c | 771 | |
9d30f3c1 JJ |
772 | FOR_EACH_BB (bb) |
773 | { | |
726a989a | 774 | gimple_stmt_iterator i; |
9d30f3c1 JJ |
775 | |
776 | si.compute_sizes = -1; | |
777 | si.bb = bb; | |
746077ff RH |
778 | |
779 | /* For va_list_simple_ptr, we have to check PHI nodes too. We treat | |
780 | them as assignments for the purpose of escape analysis. This is | |
781 | not needed for non-simple va_list because virtual phis don't perform | |
782 | any real data movement. */ | |
783 | if (va_list_simple_ptr) | |
784 | { | |
726a989a | 785 | tree lhs, rhs; |
746077ff RH |
786 | use_operand_p uop; |
787 | ssa_op_iter soi; | |
788 | ||
726a989a | 789 | for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) |
746077ff | 790 | { |
726a989a | 791 | gimple phi = gsi_stmt (i); |
746077ff RH |
792 | lhs = PHI_RESULT (phi); |
793 | ||
ea057359 | 794 | if (virtual_operand_p (lhs)) |
746077ff RH |
795 | continue; |
796 | ||
797 | FOR_EACH_PHI_ARG (uop, phi, soi, SSA_OP_USE) | |
798 | { | |
799 | rhs = USE_FROM_PTR (uop); | |
800 | if (va_list_ptr_read (&si, rhs, lhs)) | |
801 | continue; | |
802 | else if (va_list_ptr_write (&si, lhs, rhs)) | |
803 | continue; | |
804 | else | |
805 | check_va_list_escapes (&si, lhs, rhs); | |
806 | ||
726a989a | 807 | if (si.va_list_escapes) |
746077ff RH |
808 | { |
809 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
810 | { | |
811 | fputs ("va_list escapes in ", dump_file); | |
726a989a | 812 | print_gimple_stmt (dump_file, phi, 0, dump_flags); |
746077ff RH |
813 | fputc ('\n', dump_file); |
814 | } | |
815 | va_list_escapes = true; | |
816 | } | |
817 | } | |
818 | } | |
819 | } | |
820 | ||
726a989a RB |
821 | for (i = gsi_start_bb (bb); |
822 | !gsi_end_p (i) && !va_list_escapes; | |
823 | gsi_next (&i)) | |
9d30f3c1 | 824 | { |
726a989a | 825 | gimple stmt = gsi_stmt (i); |
9d30f3c1 JJ |
826 | |
827 | /* Don't look at __builtin_va_{start,end}, they are ok. */ | |
726a989a | 828 | if (is_gimple_call (stmt)) |
9d30f3c1 | 829 | { |
726a989a | 830 | tree callee = gimple_call_fndecl (stmt); |
9d30f3c1 JJ |
831 | |
832 | if (callee | |
833 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL | |
834 | && (DECL_FUNCTION_CODE (callee) == BUILT_IN_VA_START | |
835 | || DECL_FUNCTION_CODE (callee) == BUILT_IN_VA_END)) | |
836 | continue; | |
837 | } | |
838 | ||
726a989a | 839 | if (is_gimple_assign (stmt)) |
9d30f3c1 | 840 | { |
726a989a RB |
841 | tree lhs = gimple_assign_lhs (stmt); |
842 | tree rhs = gimple_assign_rhs1 (stmt); | |
9d30f3c1 JJ |
843 | |
844 | if (va_list_simple_ptr) | |
845 | { | |
726a989a RB |
846 | if (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) |
847 | == GIMPLE_SINGLE_RHS) | |
848 | { | |
bad25453 JJ |
849 | /* Check for ap ={v} {}. */ |
850 | if (TREE_CLOBBER_P (rhs)) | |
851 | continue; | |
852 | ||
726a989a | 853 | /* Check for tem = ap. */ |
bad25453 | 854 | else if (va_list_ptr_read (&si, rhs, lhs)) |
726a989a | 855 | continue; |
9d30f3c1 | 856 | |
726a989a RB |
857 | /* Check for the last insn in: |
858 | tem1 = ap; | |
859 | tem2 = tem1 + CST; | |
860 | ap = tem2; | |
861 | sequence. */ | |
862 | else if (va_list_ptr_write (&si, lhs, rhs)) | |
863 | continue; | |
864 | } | |
9d30f3c1 | 865 | |
726a989a RB |
866 | if ((gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
867 | && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST) | |
1a87cf0c | 868 | || CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)) |
726a989a RB |
869 | || (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) |
870 | == GIMPLE_SINGLE_RHS)) | |
9d30f3c1 JJ |
871 | check_va_list_escapes (&si, lhs, rhs); |
872 | } | |
873 | else | |
874 | { | |
726a989a RB |
875 | if (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) |
876 | == GIMPLE_SINGLE_RHS) | |
877 | { | |
47598145 MM |
878 | /* Check for ap ={v} {}. */ |
879 | if (TREE_CLOBBER_P (rhs)) | |
880 | continue; | |
bad25453 | 881 | |
726a989a | 882 | /* Check for ap[0].field = temp. */ |
47598145 | 883 | else if (va_list_counter_struct_op (&si, lhs, rhs, true)) |
726a989a | 884 | continue; |
9d30f3c1 | 885 | |
726a989a RB |
886 | /* Check for temp = ap[0].field. */ |
887 | else if (va_list_counter_struct_op (&si, rhs, lhs, | |
888 | false)) | |
889 | continue; | |
890 | } | |
9d30f3c1 JJ |
891 | |
892 | /* Do any architecture specific checking. */ | |
726a989a RB |
893 | if (targetm.stdarg_optimize_hook |
894 | && targetm.stdarg_optimize_hook (&si, stmt)) | |
9d30f3c1 JJ |
895 | continue; |
896 | } | |
897 | } | |
b5b8b0ac AO |
898 | else if (is_gimple_debug (stmt)) |
899 | continue; | |
9d30f3c1 JJ |
900 | |
901 | /* All other uses of va_list are either va_copy (that is not handled | |
902 | in this optimization), taking address of va_list variable or | |
903 | passing va_list to other functions (in that case va_list might | |
904 | escape the function and therefore va_start needs to set it up | |
905 | fully), or some unexpected use of va_list. None of these should | |
906 | happen in a gimplified VA_ARG_EXPR. */ | |
907 | if (si.va_list_escapes | |
726a989a | 908 | || walk_gimple_op (stmt, find_va_list_reference, &wi)) |
9d30f3c1 JJ |
909 | { |
910 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
911 | { | |
912 | fputs ("va_list escapes in ", dump_file); | |
726a989a | 913 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
9d30f3c1 JJ |
914 | fputc ('\n', dump_file); |
915 | } | |
916 | va_list_escapes = true; | |
917 | } | |
918 | } | |
919 | ||
920 | if (va_list_escapes) | |
921 | break; | |
922 | } | |
923 | ||
924 | if (! va_list_escapes | |
925 | && va_list_simple_ptr | |
926 | && ! bitmap_empty_p (si.va_list_escape_vars) | |
927 | && check_all_va_list_escapes (&si)) | |
928 | va_list_escapes = true; | |
929 | ||
930 | finish: | |
931 | if (va_list_escapes) | |
932 | { | |
933 | cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE; | |
934 | cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE; | |
935 | } | |
936 | BITMAP_FREE (si.va_list_vars); | |
937 | BITMAP_FREE (si.va_list_escape_vars); | |
938 | free (si.offsets); | |
939 | if (dump_file) | |
940 | { | |
941 | fprintf (dump_file, "%s: va_list escapes %d, needs to save ", | |
942 | funcname, (int) va_list_escapes); | |
943 | if (cfun->va_list_gpr_size >= VA_LIST_MAX_GPR_SIZE) | |
944 | fputs ("all", dump_file); | |
945 | else | |
946 | fprintf (dump_file, "%d", cfun->va_list_gpr_size); | |
947 | fputs (" GPR units and ", dump_file); | |
948 | if (cfun->va_list_fpr_size >= VA_LIST_MAX_FPR_SIZE) | |
949 | fputs ("all", dump_file); | |
950 | else | |
951 | fprintf (dump_file, "%d", cfun->va_list_fpr_size); | |
952 | fputs (" FPR units.\n", dump_file); | |
953 | } | |
c2924966 | 954 | return 0; |
9d30f3c1 JJ |
955 | } |
956 | ||
957 | ||
8ddbbcae | 958 | struct gimple_opt_pass pass_stdarg = |
9d30f3c1 | 959 | { |
8ddbbcae JH |
960 | { |
961 | GIMPLE_PASS, | |
9d30f3c1 JJ |
962 | "stdarg", /* name */ |
963 | gate_optimize_stdarg, /* gate */ | |
964 | execute_optimize_stdarg, /* execute */ | |
965 | NULL, /* sub */ | |
966 | NULL, /* next */ | |
967 | 0, /* static_pass_number */ | |
7072a650 | 968 | TV_NONE, /* tv_id */ |
4effdf02 | 969 | PROP_cfg | PROP_ssa, /* properties_required */ |
9d30f3c1 JJ |
970 | 0, /* properties_provided */ |
971 | 0, /* properties_destroyed */ | |
972 | 0, /* todo_flags_start */ | |
22c5fa5f | 973 | 0 /* todo_flags_finish */ |
8ddbbcae | 974 | } |
9d30f3c1 | 975 | }; |