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1 | /* GCC instrumentation plugin for ThreadSanitizer. |
2 | Copyright (C) 2011, 2012 Free Software Foundation, Inc. | |
3 | Contributed by Dmitry Vyukov <dvyukov@google.com> | |
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 3, 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 COPYING3. If not see | |
19 | <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | ||
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tree.h" | |
26 | #include "intl.h" | |
27 | #include "tm.h" | |
28 | #include "basic-block.h" | |
29 | #include "gimple.h" | |
30 | #include "function.h" | |
31 | #include "tree-flow.h" | |
32 | #include "tree-pass.h" | |
33 | #include "tree-iterator.h" | |
34 | #include "langhooks.h" | |
35 | #include "output.h" | |
36 | #include "options.h" | |
37 | #include "target.h" | |
38 | #include "cgraph.h" | |
39 | #include "diagnostic.h" | |
40 | ||
41 | /* Number of instrumented memory accesses in the current function. */ | |
42 | ||
43 | /* Builds the following decl | |
44 | void __tsan_read/writeX (void *addr); */ | |
45 | ||
46 | static tree | |
47 | get_memory_access_decl (bool is_write, unsigned size) | |
48 | { | |
49 | enum built_in_function fcode; | |
50 | ||
51 | if (size <= 1) | |
52 | fcode = is_write ? BUILT_IN_TSAN_WRITE_1 | |
53 | : BUILT_IN_TSAN_READ_1; | |
54 | else if (size <= 3) | |
55 | fcode = is_write ? BUILT_IN_TSAN_WRITE_2 | |
56 | : BUILT_IN_TSAN_READ_2; | |
57 | else if (size <= 7) | |
58 | fcode = is_write ? BUILT_IN_TSAN_WRITE_4 | |
59 | : BUILT_IN_TSAN_READ_4; | |
60 | else if (size <= 15) | |
61 | fcode = is_write ? BUILT_IN_TSAN_WRITE_8 | |
62 | : BUILT_IN_TSAN_READ_8; | |
63 | else | |
64 | fcode = is_write ? BUILT_IN_TSAN_WRITE_16 | |
65 | : BUILT_IN_TSAN_READ_16; | |
66 | ||
67 | return builtin_decl_implicit (fcode); | |
68 | } | |
69 | ||
70 | /* Check as to whether EXPR refers to a store to vptr. */ | |
71 | ||
72 | static tree | |
73 | is_vptr_store (gimple stmt, tree expr, bool is_write) | |
74 | { | |
75 | if (is_write == true | |
76 | && gimple_assign_single_p (stmt) | |
77 | && TREE_CODE (expr) == COMPONENT_REF) | |
78 | { | |
79 | tree field = TREE_OPERAND (expr, 1); | |
80 | if (TREE_CODE (field) == FIELD_DECL | |
81 | && DECL_VIRTUAL_P (field)) | |
82 | return gimple_assign_rhs1 (stmt); | |
83 | } | |
84 | return NULL; | |
85 | } | |
86 | ||
87 | /* Checks as to whether EXPR refers to constant var/field/param. | |
88 | Don't bother to instrument them. */ | |
89 | ||
90 | static bool | |
91 | is_load_of_const_p (tree expr, bool is_write) | |
92 | { | |
93 | if (is_write) | |
94 | return false; | |
95 | if (TREE_CODE (expr) == COMPONENT_REF) | |
96 | expr = TREE_OPERAND (expr, 1); | |
97 | if (TREE_CODE (expr) == VAR_DECL | |
98 | || TREE_CODE (expr) == PARM_DECL | |
99 | || TREE_CODE (expr) == FIELD_DECL) | |
100 | { | |
101 | if (TREE_READONLY (expr)) | |
102 | return true; | |
103 | } | |
104 | return false; | |
105 | } | |
106 | ||
107 | /* Instruments EXPR if needed. If any instrumentation is inserted, | |
108 | * return true. */ | |
109 | ||
110 | static bool | |
111 | instrument_expr (gimple_stmt_iterator gsi, tree expr, bool is_write) | |
112 | { | |
113 | enum tree_code tcode; | |
114 | tree base, rhs, expr_type, expr_ptr, builtin_decl; | |
115 | basic_block bb; | |
116 | HOST_WIDE_INT size; | |
117 | gimple stmt, g; | |
118 | location_t loc; | |
119 | ||
120 | base = get_base_address (expr); | |
121 | if (base == NULL_TREE | |
122 | || TREE_CODE (base) == SSA_NAME | |
123 | || TREE_CODE (base) == STRING_CST) | |
124 | return false; | |
125 | ||
126 | tcode = TREE_CODE (expr); | |
127 | ||
128 | /* Below are things we do not instrument | |
129 | (no possibility of races or not implemented yet). */ | |
130 | if (/* Compiler-emitted artificial variables. */ | |
131 | (DECL_P (expr) && DECL_ARTIFICIAL (expr)) | |
132 | /* The var does not live in memory -> no possibility of races. */ | |
133 | || (tcode == VAR_DECL | |
134 | && !TREE_ADDRESSABLE (expr) | |
135 | && TREE_STATIC (expr) == 0) | |
136 | /* Not implemented. */ | |
137 | || TREE_CODE (TREE_TYPE (expr)) == RECORD_TYPE | |
138 | /* Not implemented. */ | |
139 | || tcode == CONSTRUCTOR | |
140 | /* Not implemented. */ | |
141 | || tcode == PARM_DECL | |
142 | /* Load of a const variable/parameter/field. */ | |
143 | || is_load_of_const_p (expr, is_write)) | |
144 | return false; | |
145 | ||
146 | size = int_size_in_bytes (TREE_TYPE (expr)); | |
147 | if (size == -1) | |
148 | return false; | |
149 | ||
150 | /* For now just avoid instrumenting bit field acceses. | |
151 | TODO: handle bit-fields as if touching the whole field. */ | |
152 | HOST_WIDE_INT bitsize, bitpos; | |
153 | tree offset; | |
154 | enum machine_mode mode; | |
155 | int volatilep = 0, unsignedp = 0; | |
156 | get_inner_reference (expr, &bitsize, &bitpos, &offset, | |
157 | &mode, &unsignedp, &volatilep, false); | |
158 | if (bitpos % (size * BITS_PER_UNIT) | |
159 | || bitsize != size * BITS_PER_UNIT) | |
160 | return false; | |
161 | ||
162 | /* TODO: handle other case: ARRAY_RANGE_REF. */ | |
163 | if (tcode != ARRAY_REF | |
164 | && tcode != VAR_DECL | |
165 | && tcode != COMPONENT_REF | |
166 | && tcode != INDIRECT_REF | |
167 | && tcode != MEM_REF) | |
168 | return false; | |
169 | ||
170 | stmt = gsi_stmt (gsi); | |
171 | loc = gimple_location (stmt); | |
172 | rhs = is_vptr_store (stmt, expr, is_write); | |
173 | gcc_checking_assert (rhs != NULL || is_gimple_addressable (expr)); | |
174 | expr_ptr = build_fold_addr_expr (unshare_expr (expr)); | |
175 | if (rhs == NULL) | |
176 | { | |
177 | expr_type = TREE_TYPE (expr); | |
178 | while (TREE_CODE (expr_type) == ARRAY_TYPE) | |
179 | expr_type = TREE_TYPE (expr_type); | |
180 | size = int_size_in_bytes (expr_type); | |
181 | g = gimple_build_call (get_memory_access_decl (is_write, size), | |
182 | 1, expr_ptr); | |
183 | } | |
184 | else | |
185 | { | |
186 | builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_VPTR_UPDATE); | |
187 | g = gimple_build_call (builtin_decl, 1, expr_ptr); | |
188 | } | |
189 | gimple_set_location (g, loc); | |
190 | /* Instrumentation for assignment of a function result | |
191 | must be inserted after the call. Instrumentation for | |
192 | reads of function arguments must be inserted before the call. | |
193 | That's because the call can contain synchronization. */ | |
194 | if (is_gimple_call (stmt) && is_write) | |
195 | { | |
196 | /* If the call can throw, it must be the last stmt in | |
197 | a basic block, so the instrumented stmts need to be | |
198 | inserted in successor bbs. */ | |
199 | if (is_ctrl_altering_stmt (stmt)) | |
200 | { | |
201 | edge e; | |
202 | ||
203 | bb = gsi_bb (gsi); | |
204 | e = find_fallthru_edge (bb->succs); | |
205 | if (e) | |
206 | gsi_insert_seq_on_edge_immediate (e, g); | |
207 | } | |
208 | else | |
209 | gsi_insert_after (&gsi, g, GSI_NEW_STMT); | |
210 | } | |
211 | else | |
212 | gsi_insert_before (&gsi, g, GSI_SAME_STMT); | |
213 | ||
214 | return true; | |
215 | } | |
216 | ||
217 | /* Instruments the gimple pointed to by GSI. Return | |
218 | * true if func entry/exit should be instrumented. */ | |
219 | ||
220 | static bool | |
221 | instrument_gimple (gimple_stmt_iterator gsi) | |
222 | { | |
223 | gimple stmt; | |
224 | tree rhs, lhs; | |
225 | bool instrumented = false; | |
226 | ||
227 | stmt = gsi_stmt (gsi); | |
228 | if (is_gimple_call (stmt) | |
229 | && (gimple_call_fndecl (stmt) | |
230 | != builtin_decl_implicit (BUILT_IN_TSAN_INIT))) | |
231 | return true; | |
232 | else if (is_gimple_assign (stmt)) | |
233 | { | |
234 | if (gimple_store_p (stmt)) | |
235 | { | |
236 | lhs = gimple_assign_lhs (stmt); | |
237 | instrumented = instrument_expr (gsi, lhs, true); | |
238 | } | |
239 | if (gimple_assign_load_p (stmt)) | |
240 | { | |
241 | rhs = gimple_assign_rhs1 (stmt); | |
242 | instrumented = instrument_expr (gsi, rhs, false); | |
243 | } | |
244 | } | |
245 | return instrumented; | |
246 | } | |
247 | ||
248 | /* Instruments all interesting memory accesses in the current function. | |
249 | * Return true if func entry/exit should be instrumented. */ | |
250 | ||
251 | static bool | |
252 | instrument_memory_accesses (void) | |
253 | { | |
254 | basic_block bb; | |
255 | gimple_stmt_iterator gsi; | |
256 | bool fentry_exit_instrument = false; | |
257 | ||
258 | FOR_EACH_BB (bb) | |
259 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
260 | fentry_exit_instrument |= instrument_gimple (gsi); | |
261 | return fentry_exit_instrument; | |
262 | } | |
263 | ||
264 | /* Instruments function entry. */ | |
265 | ||
266 | static void | |
267 | instrument_func_entry (void) | |
268 | { | |
269 | basic_block succ_bb; | |
270 | gimple_stmt_iterator gsi; | |
271 | tree ret_addr, builtin_decl; | |
272 | gimple g; | |
273 | ||
274 | succ_bb = single_succ (ENTRY_BLOCK_PTR); | |
275 | gsi = gsi_after_labels (succ_bb); | |
276 | ||
277 | builtin_decl = builtin_decl_implicit (BUILT_IN_RETURN_ADDRESS); | |
278 | g = gimple_build_call (builtin_decl, 1, integer_zero_node); | |
279 | ret_addr = make_ssa_name (ptr_type_node, NULL); | |
280 | gimple_call_set_lhs (g, ret_addr); | |
281 | gimple_set_location (g, cfun->function_start_locus); | |
282 | gsi_insert_before (&gsi, g, GSI_SAME_STMT); | |
283 | ||
284 | builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_FUNC_ENTRY); | |
285 | g = gimple_build_call (builtin_decl, 1, ret_addr); | |
286 | gimple_set_location (g, cfun->function_start_locus); | |
287 | gsi_insert_before (&gsi, g, GSI_SAME_STMT); | |
288 | } | |
289 | ||
290 | /* Instruments function exits. */ | |
291 | ||
292 | static void | |
293 | instrument_func_exit (void) | |
294 | { | |
295 | location_t loc; | |
296 | basic_block exit_bb; | |
297 | gimple_stmt_iterator gsi; | |
298 | gimple stmt, g; | |
299 | tree builtin_decl; | |
300 | edge e; | |
301 | edge_iterator ei; | |
302 | ||
303 | /* Find all function exits. */ | |
304 | exit_bb = EXIT_BLOCK_PTR; | |
305 | FOR_EACH_EDGE (e, ei, exit_bb->preds) | |
306 | { | |
307 | gsi = gsi_last_bb (e->src); | |
308 | stmt = gsi_stmt (gsi); | |
309 | gcc_assert (gimple_code (stmt) == GIMPLE_RETURN); | |
310 | loc = gimple_location (stmt); | |
311 | builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_FUNC_EXIT); | |
312 | g = gimple_build_call (builtin_decl, 0); | |
313 | gimple_set_location (g, loc); | |
314 | gsi_insert_before (&gsi, g, GSI_SAME_STMT); | |
315 | } | |
316 | } | |
317 | ||
318 | /* ThreadSanitizer instrumentation pass. */ | |
319 | ||
320 | static unsigned | |
321 | tsan_pass (void) | |
322 | { | |
323 | if (instrument_memory_accesses ()) | |
324 | { | |
325 | instrument_func_entry (); | |
326 | instrument_func_exit (); | |
327 | } | |
328 | return 0; | |
329 | } | |
330 | ||
331 | /* The pass's gate. */ | |
332 | ||
333 | static bool | |
334 | tsan_gate (void) | |
335 | { | |
336 | return flag_tsan != 0 | |
337 | && builtin_decl_implicit_p (BUILT_IN_TSAN_INIT); | |
338 | } | |
339 | ||
340 | /* Inserts __tsan_init () into the list of CTORs. */ | |
341 | ||
342 | void | |
343 | tsan_finish_file (void) | |
344 | { | |
345 | tree ctor_statements; | |
346 | tree init_decl; | |
347 | ||
348 | ctor_statements = NULL_TREE; | |
349 | init_decl = builtin_decl_implicit (BUILT_IN_TSAN_INIT); | |
350 | append_to_statement_list (build_call_expr (init_decl, 0), | |
351 | &ctor_statements); | |
352 | cgraph_build_static_cdtor ('I', ctor_statements, | |
353 | MAX_RESERVED_INIT_PRIORITY - 1); | |
354 | } | |
355 | ||
356 | /* The pass descriptor. */ | |
357 | ||
358 | struct gimple_opt_pass pass_tsan = | |
359 | { | |
360 | { | |
361 | GIMPLE_PASS, | |
362 | "tsan", /* name */ | |
363 | OPTGROUP_NONE, /* optinfo_flags */ | |
364 | tsan_gate, /* gate */ | |
365 | tsan_pass, /* execute */ | |
366 | NULL, /* sub */ | |
367 | NULL, /* next */ | |
368 | 0, /* static_pass_number */ | |
369 | TV_NONE, /* tv_id */ | |
370 | PROP_ssa | PROP_cfg, /* properties_required */ | |
371 | 0, /* properties_provided */ | |
372 | 0, /* properties_destroyed */ | |
373 | 0, /* todo_flags_start */ | |
374 | TODO_verify_all | TODO_update_ssa | |
375 | | TODO_update_address_taken /* todo_flags_finish */ | |
376 | } | |
377 | }; | |
378 | ||
379 | static bool | |
380 | tsan_gate_O0 (void) | |
381 | { | |
382 | return flag_tsan != 0 && !optimize | |
383 | && builtin_decl_implicit_p (BUILT_IN_TSAN_INIT); | |
384 | } | |
385 | ||
386 | struct gimple_opt_pass pass_tsan_O0 = | |
387 | { | |
388 | { | |
389 | GIMPLE_PASS, | |
390 | "tsan0", /* name */ | |
391 | OPTGROUP_NONE, /* optinfo_flags */ | |
392 | tsan_gate_O0, /* gate */ | |
393 | tsan_pass, /* execute */ | |
394 | NULL, /* sub */ | |
395 | NULL, /* next */ | |
396 | 0, /* static_pass_number */ | |
397 | TV_NONE, /* tv_id */ | |
398 | PROP_ssa | PROP_cfg, /* properties_required */ | |
399 | 0, /* properties_provided */ | |
400 | 0, /* properties_destroyed */ | |
401 | 0, /* todo_flags_start */ | |
402 | TODO_verify_all | TODO_update_ssa | |
403 | | TODO_update_address_taken /* todo_flags_finish */ | |
404 | } | |
405 | }; |