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75a70cf9 | 1 | /* GIMPLE lowering pass. Converts High GIMPLE into Low GIMPLE. |
4ee9c684 | 2 | |
0b1615c1 | 3 | Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 |
fdcb802d | 4 | Free Software Foundation, Inc. |
4ee9c684 | 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 | |
8c4c00c1 | 10 | Software Foundation; either version 3, or (at your option) any later |
4ee9c684 | 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 | |
8c4c00c1 | 19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "rtl.h" | |
4ee9c684 | 28 | #include "varray.h" |
75a70cf9 | 29 | #include "gimple.h" |
30 | #include "tree-iterator.h" | |
4ee9c684 | 31 | #include "tree-inline.h" |
32 | #include "diagnostic.h" | |
33 | #include "langhooks.h" | |
34 | #include "langhooks-def.h" | |
35 | #include "tree-flow.h" | |
36 | #include "timevar.h" | |
37 | #include "except.h" | |
38 | #include "hashtab.h" | |
39 | #include "flags.h" | |
40 | #include "function.h" | |
41 | #include "expr.h" | |
42 | #include "toplev.h" | |
43 | #include "tree-pass.h" | |
44 | ||
75a70cf9 | 45 | /* The differences between High GIMPLE and Low GIMPLE are the |
46 | following: | |
47 | ||
48 | 1- Lexical scopes are removed (i.e., GIMPLE_BIND disappears). | |
49 | ||
50 | 2- GIMPLE_TRY and GIMPLE_CATCH are converted to abnormal control | |
51 | flow and exception regions are built as an on-the-side region | |
52 | hierarchy (See tree-eh.c:lower_eh_constructs). | |
53 | ||
54 | 3- Multiple identical return statements are grouped into a single | |
55 | return and gotos to the unique return site. */ | |
56 | ||
57 | /* Match a return statement with a label. During lowering, we identify | |
58 | identical return statements and replace duplicates with a jump to | |
59 | the corresponding label. */ | |
60 | struct return_statements_t | |
61 | { | |
62 | tree label; | |
63 | gimple stmt; | |
64 | }; | |
65 | typedef struct return_statements_t return_statements_t; | |
66 | ||
67 | DEF_VEC_O(return_statements_t); | |
68 | DEF_VEC_ALLOC_O(return_statements_t,heap); | |
69 | ||
4ee9c684 | 70 | struct lower_data |
71 | { | |
72 | /* Block the current statement belongs to. */ | |
73 | tree block; | |
22e30d4e | 74 | |
75a70cf9 | 75 | /* A vector of label and return statements to be moved to the end |
6c6a0f2f | 76 | of the function. */ |
75a70cf9 | 77 | VEC(return_statements_t,heap) *return_statements; |
2c8a1497 | 78 | |
a2159096 | 79 | /* True if the current statement cannot fall through. */ |
80 | bool cannot_fallthru; | |
81 | ||
2c8a1497 | 82 | /* True if the function calls __builtin_setjmp. */ |
83 | bool calls_builtin_setjmp; | |
4ee9c684 | 84 | }; |
85 | ||
75a70cf9 | 86 | static void lower_stmt (gimple_stmt_iterator *, struct lower_data *); |
87 | static void lower_gimple_bind (gimple_stmt_iterator *, struct lower_data *); | |
88 | static void lower_gimple_return (gimple_stmt_iterator *, struct lower_data *); | |
89 | static void lower_builtin_setjmp (gimple_stmt_iterator *); | |
4ee9c684 | 90 | |
75a70cf9 | 91 | |
92 | /* Lower the body of current_function_decl from High GIMPLE into Low | |
93 | GIMPLE. */ | |
4ee9c684 | 94 | |
2a1990e9 | 95 | static unsigned int |
4ee9c684 | 96 | lower_function_body (void) |
97 | { | |
98 | struct lower_data data; | |
75a70cf9 | 99 | gimple_seq body = gimple_body (current_function_decl); |
100 | gimple_seq lowered_body; | |
101 | gimple_stmt_iterator i; | |
102 | gimple bind; | |
103 | tree t; | |
104 | gimple x; | |
105 | ||
106 | /* The gimplifier should've left a body of exactly one statement, | |
107 | namely a GIMPLE_BIND. */ | |
108 | gcc_assert (gimple_seq_first (body) == gimple_seq_last (body) | |
109 | && gimple_code (gimple_seq_first_stmt (body)) == GIMPLE_BIND); | |
4ee9c684 | 110 | |
1e8e9920 | 111 | memset (&data, 0, sizeof (data)); |
4ee9c684 | 112 | data.block = DECL_INITIAL (current_function_decl); |
113 | BLOCK_SUBBLOCKS (data.block) = NULL_TREE; | |
114 | BLOCK_CHAIN (data.block) = NULL_TREE; | |
115 | TREE_ASM_WRITTEN (data.block) = 1; | |
75a70cf9 | 116 | data.return_statements = VEC_alloc (return_statements_t, heap, 8); |
117 | ||
118 | bind = gimple_seq_first_stmt (body); | |
119 | lowered_body = NULL; | |
120 | gimple_seq_add_stmt (&lowered_body, bind); | |
121 | i = gsi_start (lowered_body); | |
122 | lower_gimple_bind (&i, &data); | |
4ee9c684 | 123 | |
75a70cf9 | 124 | /* Once the old body has been lowered, replace it with the new |
125 | lowered sequence. */ | |
126 | gimple_set_body (current_function_decl, lowered_body); | |
4ee9c684 | 127 | |
75a70cf9 | 128 | i = gsi_last (lowered_body); |
751ddc2b | 129 | |
130 | /* If the function falls off the end, we need a null return statement. | |
75a70cf9 | 131 | If we've already got one in the return_statements vector, we don't |
751ddc2b | 132 | need to do anything special. Otherwise build one by hand. */ |
75a70cf9 | 133 | if (gimple_seq_may_fallthru (lowered_body) |
134 | && (VEC_empty (return_statements_t, data.return_statements) | |
135 | || gimple_return_retval (VEC_last (return_statements_t, | |
136 | data.return_statements)->stmt) != NULL)) | |
751ddc2b | 137 | { |
75a70cf9 | 138 | x = gimple_build_return (NULL); |
139 | gimple_set_location (x, cfun->function_end_locus); | |
32dedf8f | 140 | gimple_set_block (x, DECL_INITIAL (current_function_decl)); |
75a70cf9 | 141 | gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); |
751ddc2b | 142 | } |
143 | ||
144 | /* If we lowered any return statements, emit the representative | |
145 | at the end of the function. */ | |
75a70cf9 | 146 | while (!VEC_empty (return_statements_t, data.return_statements)) |
22e30d4e | 147 | { |
75a70cf9 | 148 | return_statements_t t; |
149 | ||
150 | /* Unfortunately, we can't use VEC_pop because it returns void for | |
151 | objects. */ | |
152 | t = *VEC_last (return_statements_t, data.return_statements); | |
153 | VEC_truncate (return_statements_t, | |
154 | data.return_statements, | |
155 | VEC_length (return_statements_t, | |
156 | data.return_statements) - 1); | |
157 | ||
158 | x = gimple_build_label (t.label); | |
159 | gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); | |
751ddc2b | 160 | |
161 | /* Remove the line number from the representative return statement. | |
162 | It now fills in for many such returns. Failure to remove this | |
163 | will result in incorrect results for coverage analysis. */ | |
75a70cf9 | 164 | gimple_set_location (t.stmt, UNKNOWN_LOCATION); |
165 | gsi_insert_after (&i, t.stmt, GSI_CONTINUE_LINKING); | |
22e30d4e | 166 | } |
167 | ||
2c8a1497 | 168 | /* If the function calls __builtin_setjmp, we need to emit the computed |
169 | goto that will serve as the unique dispatcher for all the receivers. */ | |
170 | if (data.calls_builtin_setjmp) | |
171 | { | |
172 | tree disp_label, disp_var, arg; | |
173 | ||
174 | /* Build 'DISP_LABEL:' and insert. */ | |
e60a6f7b | 175 | disp_label = create_artificial_label (cfun->function_end_locus); |
2c8a1497 | 176 | /* This mark will create forward edges from every call site. */ |
177 | DECL_NONLOCAL (disp_label) = 1; | |
18d50ae6 | 178 | cfun->has_nonlocal_label = 1; |
75a70cf9 | 179 | x = gimple_build_label (disp_label); |
180 | gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); | |
2c8a1497 | 181 | |
182 | /* Build 'DISP_VAR = __builtin_setjmp_dispatcher (DISP_LABEL);' | |
183 | and insert. */ | |
184 | disp_var = create_tmp_var (ptr_type_node, "setjmpvar"); | |
c2f47e15 | 185 | arg = build_addr (disp_label, current_function_decl); |
2c8a1497 | 186 | t = implicit_built_in_decls[BUILT_IN_SETJMP_DISPATCHER]; |
75a70cf9 | 187 | x = gimple_build_call (t, 1, arg); |
188 | gimple_call_set_lhs (x, disp_var); | |
2c8a1497 | 189 | |
190 | /* Build 'goto DISP_VAR;' and insert. */ | |
75a70cf9 | 191 | gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); |
192 | x = gimple_build_goto (disp_var); | |
193 | gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); | |
2c8a1497 | 194 | } |
195 | ||
0d59b19d | 196 | gcc_assert (data.block == DECL_INITIAL (current_function_decl)); |
4ee9c684 | 197 | BLOCK_SUBBLOCKS (data.block) |
198 | = blocks_nreverse (BLOCK_SUBBLOCKS (data.block)); | |
199 | ||
200 | clear_block_marks (data.block); | |
75a70cf9 | 201 | VEC_free(return_statements_t, heap, data.return_statements); |
2a1990e9 | 202 | return 0; |
4ee9c684 | 203 | } |
204 | ||
20099e35 | 205 | struct gimple_opt_pass pass_lower_cf = |
4ee9c684 | 206 | { |
20099e35 | 207 | { |
208 | GIMPLE_PASS, | |
4ee9c684 | 209 | "lower", /* name */ |
210 | NULL, /* gate */ | |
211 | lower_function_body, /* execute */ | |
212 | NULL, /* sub */ | |
213 | NULL, /* next */ | |
214 | 0, /* static_pass_number */ | |
0b1615c1 | 215 | TV_NONE, /* tv_id */ |
4ee9c684 | 216 | PROP_gimple_any, /* properties_required */ |
217 | PROP_gimple_lcf, /* properties_provided */ | |
6354626c | 218 | 0, /* properties_destroyed */ |
4ee9c684 | 219 | 0, /* todo_flags_start */ |
20099e35 | 220 | TODO_dump_func /* todo_flags_finish */ |
221 | } | |
4ee9c684 | 222 | }; |
223 | ||
224 | ||
fdcb802d | 225 | /* Verify if the type of the argument matches that of the function |
226 | declaration. If we cannot verify this or there is a mismatch, | |
19bcf521 | 227 | return false. */ |
fdcb802d | 228 | |
19bcf521 | 229 | bool |
230 | gimple_check_call_args (gimple stmt) | |
fdcb802d | 231 | { |
232 | tree fndecl, parms, p; | |
233 | unsigned int i, nargs; | |
234 | ||
fdcb802d | 235 | nargs = gimple_call_num_args (stmt); |
236 | ||
237 | /* Get argument types for verification. */ | |
238 | fndecl = gimple_call_fndecl (stmt); | |
239 | parms = NULL_TREE; | |
240 | if (fndecl) | |
241 | parms = TYPE_ARG_TYPES (TREE_TYPE (fndecl)); | |
242 | else if (POINTER_TYPE_P (TREE_TYPE (gimple_call_fn (stmt)))) | |
243 | parms = TYPE_ARG_TYPES (TREE_TYPE (TREE_TYPE (gimple_call_fn (stmt)))); | |
244 | ||
245 | /* Verify if the type of the argument matches that of the function | |
246 | declaration. If we cannot verify this or there is a mismatch, | |
19bcf521 | 247 | return false. */ |
fdcb802d | 248 | if (fndecl && DECL_ARGUMENTS (fndecl)) |
249 | { | |
250 | for (i = 0, p = DECL_ARGUMENTS (fndecl); | |
251 | i < nargs; | |
252 | i++, p = TREE_CHAIN (p)) | |
253 | { | |
254 | /* We cannot distinguish a varargs function from the case | |
255 | of excess parameters, still deferring the inlining decision | |
256 | to the callee is possible. */ | |
257 | if (!p) | |
258 | break; | |
259 | if (p == error_mark_node | |
260 | || gimple_call_arg (stmt, i) == error_mark_node | |
261 | || !fold_convertible_p (DECL_ARG_TYPE (p), | |
262 | gimple_call_arg (stmt, i))) | |
19bcf521 | 263 | return false; |
fdcb802d | 264 | } |
265 | } | |
266 | else if (parms) | |
267 | { | |
268 | for (i = 0, p = parms; i < nargs; i++, p = TREE_CHAIN (p)) | |
269 | { | |
270 | /* If this is a varargs function defer inlining decision | |
271 | to callee. */ | |
272 | if (!p) | |
273 | break; | |
274 | if (TREE_VALUE (p) == error_mark_node | |
275 | || gimple_call_arg (stmt, i) == error_mark_node | |
276 | || TREE_CODE (TREE_VALUE (p)) == VOID_TYPE | |
277 | || !fold_convertible_p (TREE_VALUE (p), | |
278 | gimple_call_arg (stmt, i))) | |
19bcf521 | 279 | return false; |
fdcb802d | 280 | } |
281 | } | |
282 | else | |
283 | { | |
284 | if (nargs != 0) | |
19bcf521 | 285 | return false; |
fdcb802d | 286 | } |
19bcf521 | 287 | return true; |
fdcb802d | 288 | } |
289 | ||
290 | ||
75a70cf9 | 291 | /* Lower sequence SEQ. Unlike gimplification the statements are not relowered |
4ee9c684 | 292 | when they are changed -- if this has to be done, the lowering routine must |
293 | do it explicitly. DATA is passed through the recursion. */ | |
294 | ||
c939e803 | 295 | static void |
75a70cf9 | 296 | lower_sequence (gimple_seq seq, struct lower_data *data) |
4ee9c684 | 297 | { |
75a70cf9 | 298 | gimple_stmt_iterator gsi; |
4ee9c684 | 299 | |
75a70cf9 | 300 | for (gsi = gsi_start (seq); !gsi_end_p (gsi); ) |
301 | lower_stmt (&gsi, data); | |
4ee9c684 | 302 | } |
303 | ||
773c5ba7 | 304 | |
75a70cf9 | 305 | /* Lower the OpenMP directive statement pointed by GSI. DATA is |
773c5ba7 | 306 | passed through the recursion. */ |
307 | ||
308 | static void | |
75a70cf9 | 309 | lower_omp_directive (gimple_stmt_iterator *gsi, struct lower_data *data) |
773c5ba7 | 310 | { |
75a70cf9 | 311 | gimple stmt; |
773c5ba7 | 312 | |
75a70cf9 | 313 | stmt = gsi_stmt (*gsi); |
773c5ba7 | 314 | |
75a70cf9 | 315 | lower_sequence (gimple_omp_body (stmt), data); |
316 | gsi_insert_before (gsi, stmt, GSI_SAME_STMT); | |
317 | gsi_insert_seq_before (gsi, gimple_omp_body (stmt), GSI_SAME_STMT); | |
318 | gimple_omp_set_body (stmt, NULL); | |
319 | gsi_remove (gsi, false); | |
773c5ba7 | 320 | } |
321 | ||
322 | ||
a2159096 | 323 | /* Lower statement GSI. DATA is passed through the recursion. We try to |
324 | track the fallthruness of statements and get rid of unreachable return | |
325 | statements in order to prevent the EH lowering pass from adding useless | |
326 | edges that can cause bogus warnings to be issued later; this guess need | |
327 | not be 100% accurate, simply be conservative and reset cannot_fallthru | |
328 | to false if we don't know. */ | |
4ee9c684 | 329 | |
330 | static void | |
75a70cf9 | 331 | lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data) |
4ee9c684 | 332 | { |
75a70cf9 | 333 | gimple stmt = gsi_stmt (*gsi); |
4ee9c684 | 334 | |
75a70cf9 | 335 | gimple_set_block (stmt, data->block); |
4ee9c684 | 336 | |
75a70cf9 | 337 | switch (gimple_code (stmt)) |
4ee9c684 | 338 | { |
75a70cf9 | 339 | case GIMPLE_BIND: |
340 | lower_gimple_bind (gsi, data); | |
a2159096 | 341 | /* Propagate fallthruness. */ |
22e30d4e | 342 | return; |
4ee9c684 | 343 | |
75a70cf9 | 344 | case GIMPLE_COND: |
a2159096 | 345 | case GIMPLE_GOTO: |
346 | case GIMPLE_SWITCH: | |
347 | data->cannot_fallthru = true; | |
348 | gsi_next (gsi); | |
349 | return; | |
75a70cf9 | 350 | |
351 | case GIMPLE_RETURN: | |
a2159096 | 352 | if (data->cannot_fallthru) |
353 | { | |
354 | gsi_remove (gsi, false); | |
355 | /* Propagate fallthruness. */ | |
356 | } | |
357 | else | |
358 | { | |
359 | lower_gimple_return (gsi, data); | |
360 | data->cannot_fallthru = true; | |
361 | } | |
75a70cf9 | 362 | return; |
363 | ||
364 | case GIMPLE_TRY: | |
a2159096 | 365 | { |
366 | bool try_cannot_fallthru; | |
367 | lower_sequence (gimple_try_eval (stmt), data); | |
368 | try_cannot_fallthru = data->cannot_fallthru; | |
369 | data->cannot_fallthru = false; | |
370 | lower_sequence (gimple_try_cleanup (stmt), data); | |
371 | /* See gimple_stmt_may_fallthru for the rationale. */ | |
372 | if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY) | |
373 | { | |
374 | data->cannot_fallthru |= try_cannot_fallthru; | |
375 | gsi_next (gsi); | |
376 | return; | |
377 | } | |
378 | } | |
4ee9c684 | 379 | break; |
75a70cf9 | 380 | |
381 | case GIMPLE_CATCH: | |
a2159096 | 382 | data->cannot_fallthru = false; |
75a70cf9 | 383 | lower_sequence (gimple_catch_handler (stmt), data); |
4ee9c684 | 384 | break; |
75a70cf9 | 385 | |
386 | case GIMPLE_EH_FILTER: | |
a2159096 | 387 | data->cannot_fallthru = false; |
75a70cf9 | 388 | lower_sequence (gimple_eh_filter_failure (stmt), data); |
61e47ac8 | 389 | break; |
390 | ||
75a70cf9 | 391 | case GIMPLE_NOP: |
392 | case GIMPLE_ASM: | |
393 | case GIMPLE_ASSIGN: | |
75a70cf9 | 394 | case GIMPLE_PREDICT: |
395 | case GIMPLE_LABEL: | |
e38def9c | 396 | case GIMPLE_EH_MUST_NOT_THROW: |
75a70cf9 | 397 | case GIMPLE_OMP_FOR: |
398 | case GIMPLE_OMP_SECTIONS: | |
399 | case GIMPLE_OMP_SECTIONS_SWITCH: | |
400 | case GIMPLE_OMP_SECTION: | |
401 | case GIMPLE_OMP_SINGLE: | |
402 | case GIMPLE_OMP_MASTER: | |
403 | case GIMPLE_OMP_ORDERED: | |
404 | case GIMPLE_OMP_CRITICAL: | |
405 | case GIMPLE_OMP_RETURN: | |
406 | case GIMPLE_OMP_ATOMIC_LOAD: | |
407 | case GIMPLE_OMP_ATOMIC_STORE: | |
408 | case GIMPLE_OMP_CONTINUE: | |
409 | break; | |
2c8a1497 | 410 | |
75a70cf9 | 411 | case GIMPLE_CALL: |
2c8a1497 | 412 | { |
75a70cf9 | 413 | tree decl = gimple_call_fndecl (stmt); |
414 | ||
2c8a1497 | 415 | if (decl |
416 | && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL | |
417 | && DECL_FUNCTION_CODE (decl) == BUILT_IN_SETJMP) | |
418 | { | |
75a70cf9 | 419 | lower_builtin_setjmp (gsi); |
a2159096 | 420 | data->cannot_fallthru = false; |
421 | data->calls_builtin_setjmp = true; | |
2c8a1497 | 422 | return; |
423 | } | |
264ee46d | 424 | |
264ee46d | 425 | if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN)) |
426 | { | |
a2159096 | 427 | data->cannot_fallthru = true; |
264ee46d | 428 | gsi_next (gsi); |
264ee46d | 429 | return; |
430 | } | |
2c8a1497 | 431 | } |
432 | break; | |
433 | ||
75a70cf9 | 434 | case GIMPLE_OMP_PARALLEL: |
435 | case GIMPLE_OMP_TASK: | |
a2159096 | 436 | data->cannot_fallthru = false; |
75a70cf9 | 437 | lower_omp_directive (gsi, data); |
a2159096 | 438 | data->cannot_fallthru = false; |
773c5ba7 | 439 | return; |
440 | ||
4ee9c684 | 441 | default: |
0d59b19d | 442 | gcc_unreachable (); |
4ee9c684 | 443 | } |
444 | ||
a2159096 | 445 | data->cannot_fallthru = false; |
75a70cf9 | 446 | gsi_next (gsi); |
4ee9c684 | 447 | } |
448 | ||
2c8a1497 | 449 | /* Lower a bind_expr TSI. DATA is passed through the recursion. */ |
4ee9c684 | 450 | |
451 | static void | |
75a70cf9 | 452 | lower_gimple_bind (gimple_stmt_iterator *gsi, struct lower_data *data) |
4ee9c684 | 453 | { |
454 | tree old_block = data->block; | |
75a70cf9 | 455 | gimple stmt = gsi_stmt (*gsi); |
456 | tree new_block = gimple_bind_block (stmt); | |
4ee9c684 | 457 | |
458 | if (new_block) | |
459 | { | |
460 | if (new_block == old_block) | |
461 | { | |
462 | /* The outermost block of the original function may not be the | |
463 | outermost statement chain of the gimplified function. So we | |
464 | may see the outermost block just inside the function. */ | |
0d59b19d | 465 | gcc_assert (new_block == DECL_INITIAL (current_function_decl)); |
4ee9c684 | 466 | new_block = NULL; |
467 | } | |
468 | else | |
469 | { | |
470 | /* We do not expect to handle duplicate blocks. */ | |
0d59b19d | 471 | gcc_assert (!TREE_ASM_WRITTEN (new_block)); |
4ee9c684 | 472 | TREE_ASM_WRITTEN (new_block) = 1; |
473 | ||
474 | /* Block tree may get clobbered by inlining. Normally this would | |
475 | be fixed in rest_of_decl_compilation using block notes, but | |
476 | since we are not going to emit them, it is up to us. */ | |
477 | BLOCK_CHAIN (new_block) = BLOCK_SUBBLOCKS (old_block); | |
478 | BLOCK_SUBBLOCKS (old_block) = new_block; | |
479 | BLOCK_SUBBLOCKS (new_block) = NULL_TREE; | |
480 | BLOCK_SUPERCONTEXT (new_block) = old_block; | |
481 | ||
482 | data->block = new_block; | |
483 | } | |
484 | } | |
485 | ||
75a70cf9 | 486 | record_vars (gimple_bind_vars (stmt)); |
487 | lower_sequence (gimple_bind_body (stmt), data); | |
4ee9c684 | 488 | |
489 | if (new_block) | |
490 | { | |
0d59b19d | 491 | gcc_assert (data->block == new_block); |
4ee9c684 | 492 | |
493 | BLOCK_SUBBLOCKS (new_block) | |
494 | = blocks_nreverse (BLOCK_SUBBLOCKS (new_block)); | |
495 | data->block = old_block; | |
496 | } | |
497 | ||
75a70cf9 | 498 | /* The GIMPLE_BIND no longer carries any useful information -- kill it. */ |
499 | gsi_insert_seq_before (gsi, gimple_bind_body (stmt), GSI_SAME_STMT); | |
500 | gsi_remove (gsi, false); | |
4ee9c684 | 501 | } |
502 | ||
93f29170 | 503 | /* Try to determine whether a TRY_CATCH expression can fall through. |
504 | This is a subroutine of block_may_fallthru. */ | |
505 | ||
506 | static bool | |
1f1872fd | 507 | try_catch_may_fallthru (const_tree stmt) |
93f29170 | 508 | { |
509 | tree_stmt_iterator i; | |
510 | ||
511 | /* If the TRY block can fall through, the whole TRY_CATCH can | |
512 | fall through. */ | |
513 | if (block_may_fallthru (TREE_OPERAND (stmt, 0))) | |
514 | return true; | |
515 | ||
516 | i = tsi_start (TREE_OPERAND (stmt, 1)); | |
517 | switch (TREE_CODE (tsi_stmt (i))) | |
518 | { | |
519 | case CATCH_EXPR: | |
520 | /* We expect to see a sequence of CATCH_EXPR trees, each with a | |
521 | catch expression and a body. The whole TRY_CATCH may fall | |
522 | through iff any of the catch bodies falls through. */ | |
523 | for (; !tsi_end_p (i); tsi_next (&i)) | |
524 | { | |
525 | if (block_may_fallthru (CATCH_BODY (tsi_stmt (i)))) | |
526 | return true; | |
527 | } | |
528 | return false; | |
529 | ||
530 | case EH_FILTER_EXPR: | |
5cf68346 | 531 | /* The exception filter expression only matters if there is an |
532 | exception. If the exception does not match EH_FILTER_TYPES, | |
533 | we will execute EH_FILTER_FAILURE, and we will fall through | |
534 | if that falls through. If the exception does match | |
535 | EH_FILTER_TYPES, the stack unwinder will continue up the | |
536 | stack, so we will not fall through. We don't know whether we | |
537 | will throw an exception which matches EH_FILTER_TYPES or not, | |
538 | so we just ignore EH_FILTER_TYPES and assume that we might | |
539 | throw an exception which doesn't match. */ | |
540 | return block_may_fallthru (EH_FILTER_FAILURE (tsi_stmt (i))); | |
93f29170 | 541 | |
542 | default: | |
543 | /* This case represents statements to be executed when an | |
544 | exception occurs. Those statements are implicitly followed | |
e38def9c | 545 | by a RESX statement to resume execution after the exception. |
546 | So in this case the TRY_CATCH never falls through. */ | |
93f29170 | 547 | return false; |
548 | } | |
549 | } | |
550 | ||
75a70cf9 | 551 | |
552 | /* Same as above, but for a GIMPLE_TRY_CATCH. */ | |
553 | ||
554 | static bool | |
555 | gimple_try_catch_may_fallthru (gimple stmt) | |
556 | { | |
557 | gimple_stmt_iterator i; | |
558 | ||
559 | /* We don't handle GIMPLE_TRY_FINALLY. */ | |
560 | gcc_assert (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH); | |
561 | ||
562 | /* If the TRY block can fall through, the whole TRY_CATCH can | |
563 | fall through. */ | |
564 | if (gimple_seq_may_fallthru (gimple_try_eval (stmt))) | |
565 | return true; | |
566 | ||
567 | i = gsi_start (gimple_try_cleanup (stmt)); | |
568 | switch (gimple_code (gsi_stmt (i))) | |
569 | { | |
570 | case GIMPLE_CATCH: | |
571 | /* We expect to see a sequence of GIMPLE_CATCH stmts, each with a | |
572 | catch expression and a body. The whole try/catch may fall | |
573 | through iff any of the catch bodies falls through. */ | |
574 | for (; !gsi_end_p (i); gsi_next (&i)) | |
575 | { | |
576 | if (gimple_seq_may_fallthru (gimple_catch_handler (gsi_stmt (i)))) | |
577 | return true; | |
578 | } | |
579 | return false; | |
580 | ||
581 | case GIMPLE_EH_FILTER: | |
582 | /* The exception filter expression only matters if there is an | |
583 | exception. If the exception does not match EH_FILTER_TYPES, | |
584 | we will execute EH_FILTER_FAILURE, and we will fall through | |
585 | if that falls through. If the exception does match | |
586 | EH_FILTER_TYPES, the stack unwinder will continue up the | |
587 | stack, so we will not fall through. We don't know whether we | |
588 | will throw an exception which matches EH_FILTER_TYPES or not, | |
589 | so we just ignore EH_FILTER_TYPES and assume that we might | |
590 | throw an exception which doesn't match. */ | |
591 | return gimple_seq_may_fallthru (gimple_eh_filter_failure (gsi_stmt (i))); | |
592 | ||
593 | default: | |
594 | /* This case represents statements to be executed when an | |
595 | exception occurs. Those statements are implicitly followed | |
596 | by a GIMPLE_RESX to resume execution after the exception. So | |
597 | in this case the try/catch never falls through. */ | |
598 | return false; | |
599 | } | |
600 | } | |
601 | ||
602 | ||
4ee9c684 | 603 | /* Try to determine if we can fall out of the bottom of BLOCK. This guess |
604 | need not be 100% accurate; simply be conservative and return true if we | |
605 | don't know. This is used only to avoid stupidly generating extra code. | |
606 | If we're wrong, we'll just delete the extra code later. */ | |
607 | ||
608 | bool | |
1f1872fd | 609 | block_may_fallthru (const_tree block) |
4ee9c684 | 610 | { |
5ca94202 | 611 | /* This CONST_CAST is okay because expr_last returns its argument |
ce4469fa | 612 | unmodified and we assign it to a const_tree. */ |
e47a6f81 | 613 | const_tree stmt = expr_last (CONST_CAST_TREE(block)); |
4ee9c684 | 614 | |
615 | switch (stmt ? TREE_CODE (stmt) : ERROR_MARK) | |
616 | { | |
617 | case GOTO_EXPR: | |
618 | case RETURN_EXPR: | |
4ee9c684 | 619 | /* Easy cases. If the last statement of the block implies |
620 | control transfer, then we can't fall through. */ | |
621 | return false; | |
622 | ||
7f0f308d | 623 | case SWITCH_EXPR: |
624 | /* If SWITCH_LABELS is set, this is lowered, and represents a | |
625 | branch to a selected label and hence can not fall through. | |
626 | Otherwise SWITCH_BODY is set, and the switch can fall | |
627 | through. */ | |
ec20cf72 | 628 | return SWITCH_LABELS (stmt) == NULL_TREE; |
7f0f308d | 629 | |
4ee9c684 | 630 | case COND_EXPR: |
631 | if (block_may_fallthru (COND_EXPR_THEN (stmt))) | |
632 | return true; | |
633 | return block_may_fallthru (COND_EXPR_ELSE (stmt)); | |
634 | ||
635 | case BIND_EXPR: | |
636 | return block_may_fallthru (BIND_EXPR_BODY (stmt)); | |
637 | ||
93f29170 | 638 | case TRY_CATCH_EXPR: |
639 | return try_catch_may_fallthru (stmt); | |
640 | ||
4ee9c684 | 641 | case TRY_FINALLY_EXPR: |
0ac5fbe2 | 642 | /* The finally clause is always executed after the try clause, |
643 | so if it does not fall through, then the try-finally will not | |
644 | fall through. Otherwise, if the try clause does not fall | |
645 | through, then when the finally clause falls through it will | |
646 | resume execution wherever the try clause was going. So the | |
647 | whole try-finally will only fall through if both the try | |
648 | clause and the finally clause fall through. */ | |
649 | return (block_may_fallthru (TREE_OPERAND (stmt, 0)) | |
650 | && block_may_fallthru (TREE_OPERAND (stmt, 1))); | |
4ee9c684 | 651 | |
75a70cf9 | 652 | case MODIFY_EXPR: |
653 | if (TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR) | |
654 | stmt = TREE_OPERAND (stmt, 1); | |
4ee9c684 | 655 | else |
656 | return true; | |
657 | /* FALLTHRU */ | |
658 | ||
659 | case CALL_EXPR: | |
660 | /* Functions that do not return do not fall through. */ | |
661 | return (call_expr_flags (stmt) & ECF_NORETURN) == 0; | |
17fd1194 | 662 | |
663 | case CLEANUP_POINT_EXPR: | |
664 | return block_may_fallthru (TREE_OPERAND (stmt, 0)); | |
4ee9c684 | 665 | |
666 | default: | |
667 | return true; | |
668 | } | |
669 | } | |
670 | ||
4ee9c684 | 671 | |
75a70cf9 | 672 | /* Try to determine if we can continue executing the statement |
673 | immediately following STMT. This guess need not be 100% accurate; | |
674 | simply be conservative and return true if we don't know. This is | |
675 | used only to avoid stupidly generating extra code. If we're wrong, | |
676 | we'll just delete the extra code later. */ | |
677 | ||
678 | bool | |
679 | gimple_stmt_may_fallthru (gimple stmt) | |
4ee9c684 | 680 | { |
75a70cf9 | 681 | if (!stmt) |
682 | return true; | |
4ee9c684 | 683 | |
75a70cf9 | 684 | switch (gimple_code (stmt)) |
685 | { | |
686 | case GIMPLE_GOTO: | |
687 | case GIMPLE_RETURN: | |
688 | case GIMPLE_RESX: | |
689 | /* Easy cases. If the last statement of the seq implies | |
690 | control transfer, then we can't fall through. */ | |
691 | return false; | |
4ee9c684 | 692 | |
75a70cf9 | 693 | case GIMPLE_SWITCH: |
a2159096 | 694 | /* Switch has already been lowered and represents a branch |
695 | to a selected label and hence can't fall through. */ | |
696 | return false; | |
4ee9c684 | 697 | |
75a70cf9 | 698 | case GIMPLE_COND: |
699 | /* GIMPLE_COND's are already lowered into a two-way branch. They | |
700 | can't fall through. */ | |
701 | return false; | |
4ee9c684 | 702 | |
75a70cf9 | 703 | case GIMPLE_BIND: |
704 | return gimple_seq_may_fallthru (gimple_bind_body (stmt)); | |
4ee9c684 | 705 | |
75a70cf9 | 706 | case GIMPLE_TRY: |
707 | if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH) | |
708 | return gimple_try_catch_may_fallthru (stmt); | |
4ee9c684 | 709 | |
75a70cf9 | 710 | /* It must be a GIMPLE_TRY_FINALLY. */ |
4ee9c684 | 711 | |
75a70cf9 | 712 | /* The finally clause is always executed after the try clause, |
713 | so if it does not fall through, then the try-finally will not | |
714 | fall through. Otherwise, if the try clause does not fall | |
715 | through, then when the finally clause falls through it will | |
716 | resume execution wherever the try clause was going. So the | |
717 | whole try-finally will only fall through if both the try | |
718 | clause and the finally clause fall through. */ | |
719 | return (gimple_seq_may_fallthru (gimple_try_eval (stmt)) | |
720 | && gimple_seq_may_fallthru (gimple_try_cleanup (stmt))); | |
721 | ||
75a70cf9 | 722 | case GIMPLE_CALL: |
723 | /* Functions that do not return do not fall through. */ | |
724 | return (gimple_call_flags (stmt) & ECF_NORETURN) == 0; | |
a2159096 | 725 | |
75a70cf9 | 726 | default: |
727 | return true; | |
4ee9c684 | 728 | } |
75a70cf9 | 729 | } |
730 | ||
4ee9c684 | 731 | |
75a70cf9 | 732 | /* Same as gimple_stmt_may_fallthru, but for the gimple sequence SEQ. */ |
4ee9c684 | 733 | |
75a70cf9 | 734 | bool |
735 | gimple_seq_may_fallthru (gimple_seq seq) | |
736 | { | |
737 | return gimple_stmt_may_fallthru (gimple_seq_last_stmt (seq)); | |
4ee9c684 | 738 | } |
22e30d4e | 739 | |
75a70cf9 | 740 | |
741 | /* Lower a GIMPLE_RETURN GSI. DATA is passed through the recursion. */ | |
2c8a1497 | 742 | |
22e30d4e | 743 | static void |
75a70cf9 | 744 | lower_gimple_return (gimple_stmt_iterator *gsi, struct lower_data *data) |
22e30d4e | 745 | { |
75a70cf9 | 746 | gimple stmt = gsi_stmt (*gsi); |
747 | gimple t; | |
748 | int i; | |
749 | return_statements_t tmp_rs; | |
22e30d4e | 750 | |
6c6a0f2f | 751 | /* Match this up with an existing return statement that's been created. */ |
75a70cf9 | 752 | for (i = VEC_length (return_statements_t, data->return_statements) - 1; |
753 | i >= 0; i--) | |
22e30d4e | 754 | { |
75a70cf9 | 755 | tmp_rs = *VEC_index (return_statements_t, data->return_statements, i); |
6c6a0f2f | 756 | |
75a70cf9 | 757 | if (gimple_return_retval (stmt) == gimple_return_retval (tmp_rs.stmt)) |
758 | goto found; | |
22e30d4e | 759 | } |
760 | ||
6c6a0f2f | 761 | /* Not found. Create a new label and record the return statement. */ |
e60a6f7b | 762 | tmp_rs.label = create_artificial_label (cfun->function_end_locus); |
75a70cf9 | 763 | tmp_rs.stmt = stmt; |
764 | VEC_safe_push (return_statements_t, heap, data->return_statements, &tmp_rs); | |
6c6a0f2f | 765 | |
766 | /* Generate a goto statement and remove the return statement. */ | |
767 | found: | |
75a70cf9 | 768 | t = gimple_build_goto (tmp_rs.label); |
769 | gimple_set_location (t, gimple_location (stmt)); | |
32dedf8f | 770 | gimple_set_block (t, gimple_block (stmt)); |
75a70cf9 | 771 | gsi_insert_before (gsi, t, GSI_SAME_STMT); |
772 | gsi_remove (gsi, false); | |
2c8a1497 | 773 | } |
774 | ||
a2159096 | 775 | /* Lower a __builtin_setjmp GSI. |
2c8a1497 | 776 | |
777 | __builtin_setjmp is passed a pointer to an array of five words (not | |
778 | all will be used on all machines). It operates similarly to the C | |
779 | library function of the same name, but is more efficient. | |
780 | ||
781 | It is lowered into 3 other builtins, namely __builtin_setjmp_setup, | |
782 | __builtin_setjmp_dispatcher and __builtin_setjmp_receiver, but with | |
783 | __builtin_setjmp_dispatcher shared among all the instances; that's | |
784 | why it is only emitted at the end by lower_function_body. | |
785 | ||
786 | After full lowering, the body of the function should look like: | |
787 | ||
788 | { | |
789 | void * setjmpvar.0; | |
790 | int D.1844; | |
791 | int D.2844; | |
792 | ||
793 | [...] | |
794 | ||
795 | __builtin_setjmp_setup (&buf, &<D1847>); | |
796 | D.1844 = 0; | |
797 | goto <D1846>; | |
798 | <D1847>:; | |
799 | __builtin_setjmp_receiver (&<D1847>); | |
800 | D.1844 = 1; | |
801 | <D1846>:; | |
802 | if (D.1844 == 0) goto <D1848>; else goto <D1849>; | |
803 | ||
804 | [...] | |
805 | ||
806 | __builtin_setjmp_setup (&buf, &<D2847>); | |
807 | D.2844 = 0; | |
808 | goto <D2846>; | |
809 | <D2847>:; | |
810 | __builtin_setjmp_receiver (&<D2847>); | |
811 | D.2844 = 1; | |
812 | <D2846>:; | |
813 | if (D.2844 == 0) goto <D2848>; else goto <D2849>; | |
814 | ||
815 | [...] | |
816 | ||
817 | <D3850>:; | |
818 | return; | |
819 | <D3853>: [non-local]; | |
820 | setjmpvar.0 = __builtin_setjmp_dispatcher (&<D3853>); | |
821 | goto setjmpvar.0; | |
822 | } | |
823 | ||
824 | The dispatcher block will be both the unique destination of all the | |
825 | abnormal call edges and the unique source of all the abnormal edges | |
826 | to the receivers, thus keeping the complexity explosion localized. */ | |
827 | ||
828 | static void | |
75a70cf9 | 829 | lower_builtin_setjmp (gimple_stmt_iterator *gsi) |
2c8a1497 | 830 | { |
75a70cf9 | 831 | gimple stmt = gsi_stmt (*gsi); |
e60a6f7b | 832 | location_t loc = gimple_location (stmt); |
833 | tree cont_label = create_artificial_label (loc); | |
834 | tree next_label = create_artificial_label (loc); | |
2c8a1497 | 835 | tree dest, t, arg; |
75a70cf9 | 836 | gimple g; |
2c8a1497 | 837 | |
838 | /* NEXT_LABEL is the label __builtin_longjmp will jump to. Its address is | |
839 | passed to both __builtin_setjmp_setup and __builtin_setjmp_receiver. */ | |
840 | FORCED_LABEL (next_label) = 1; | |
841 | ||
75a70cf9 | 842 | dest = gimple_call_lhs (stmt); |
2c8a1497 | 843 | |
844 | /* Build '__builtin_setjmp_setup (BUF, NEXT_LABEL)' and insert. */ | |
c2f47e15 | 845 | arg = build_addr (next_label, current_function_decl); |
2c8a1497 | 846 | t = implicit_built_in_decls[BUILT_IN_SETJMP_SETUP]; |
75a70cf9 | 847 | g = gimple_build_call (t, 2, gimple_call_arg (stmt, 0), arg); |
389dd41b | 848 | gimple_set_location (g, loc); |
32dedf8f | 849 | gimple_set_block (g, gimple_block (stmt)); |
75a70cf9 | 850 | gsi_insert_before (gsi, g, GSI_SAME_STMT); |
2c8a1497 | 851 | |
852 | /* Build 'DEST = 0' and insert. */ | |
853 | if (dest) | |
854 | { | |
389dd41b | 855 | g = gimple_build_assign (dest, fold_convert_loc (loc, TREE_TYPE (dest), |
856 | integer_zero_node)); | |
857 | gimple_set_location (g, loc); | |
32dedf8f | 858 | gimple_set_block (g, gimple_block (stmt)); |
75a70cf9 | 859 | gsi_insert_before (gsi, g, GSI_SAME_STMT); |
2c8a1497 | 860 | } |
861 | ||
862 | /* Build 'goto CONT_LABEL' and insert. */ | |
75a70cf9 | 863 | g = gimple_build_goto (cont_label); |
b9c74b4d | 864 | gsi_insert_before (gsi, g, GSI_SAME_STMT); |
2c8a1497 | 865 | |
866 | /* Build 'NEXT_LABEL:' and insert. */ | |
75a70cf9 | 867 | g = gimple_build_label (next_label); |
868 | gsi_insert_before (gsi, g, GSI_SAME_STMT); | |
2c8a1497 | 869 | |
870 | /* Build '__builtin_setjmp_receiver (NEXT_LABEL)' and insert. */ | |
c2f47e15 | 871 | arg = build_addr (next_label, current_function_decl); |
2c8a1497 | 872 | t = implicit_built_in_decls[BUILT_IN_SETJMP_RECEIVER]; |
75a70cf9 | 873 | g = gimple_build_call (t, 1, arg); |
389dd41b | 874 | gimple_set_location (g, loc); |
32dedf8f | 875 | gimple_set_block (g, gimple_block (stmt)); |
75a70cf9 | 876 | gsi_insert_before (gsi, g, GSI_SAME_STMT); |
2c8a1497 | 877 | |
878 | /* Build 'DEST = 1' and insert. */ | |
879 | if (dest) | |
880 | { | |
389dd41b | 881 | g = gimple_build_assign (dest, fold_convert_loc (loc, TREE_TYPE (dest), |
882 | integer_one_node)); | |
883 | gimple_set_location (g, loc); | |
32dedf8f | 884 | gimple_set_block (g, gimple_block (stmt)); |
75a70cf9 | 885 | gsi_insert_before (gsi, g, GSI_SAME_STMT); |
2c8a1497 | 886 | } |
887 | ||
888 | /* Build 'CONT_LABEL:' and insert. */ | |
75a70cf9 | 889 | g = gimple_build_label (cont_label); |
890 | gsi_insert_before (gsi, g, GSI_SAME_STMT); | |
2c8a1497 | 891 | |
892 | /* Remove the call to __builtin_setjmp. */ | |
75a70cf9 | 893 | gsi_remove (gsi, false); |
22e30d4e | 894 | } |
4ee9c684 | 895 | \f |
896 | ||
773c5ba7 | 897 | /* Record the variables in VARS into function FN. */ |
4ee9c684 | 898 | |
899 | void | |
773c5ba7 | 900 | record_vars_into (tree vars, tree fn) |
4ee9c684 | 901 | { |
773c5ba7 | 902 | if (fn != current_function_decl) |
87d4aa85 | 903 | push_cfun (DECL_STRUCT_FUNCTION (fn)); |
773c5ba7 | 904 | |
4ee9c684 | 905 | for (; vars; vars = TREE_CHAIN (vars)) |
906 | { | |
907 | tree var = vars; | |
908 | ||
b3d24a23 | 909 | /* BIND_EXPRs contains also function/type/constant declarations |
910 | we don't need to care about. */ | |
911 | if (TREE_CODE (var) != VAR_DECL) | |
912 | continue; | |
773c5ba7 | 913 | |
4ee9c684 | 914 | /* Nothing to do in this case. */ |
915 | if (DECL_EXTERNAL (var)) | |
916 | continue; | |
4ee9c684 | 917 | |
918 | /* Record the variable. */ | |
edb7afe8 | 919 | cfun->local_decls = tree_cons (NULL_TREE, var, |
920 | cfun->local_decls); | |
4ee9c684 | 921 | } |
773c5ba7 | 922 | |
923 | if (fn != current_function_decl) | |
87d4aa85 | 924 | pop_cfun (); |
773c5ba7 | 925 | } |
926 | ||
927 | ||
928 | /* Record the variables in VARS into current_function_decl. */ | |
929 | ||
930 | void | |
931 | record_vars (tree vars) | |
932 | { | |
933 | record_vars_into (vars, current_function_decl); | |
4ee9c684 | 934 | } |