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02d27625 MM |
1 | /* Branch trace support for GDB, the GNU debugger. |
2 | ||
3 | Copyright (C) 2013 Free Software Foundation, Inc. | |
4 | ||
5 | Contributed by Intel Corp. <markus.t.metzger@intel.com> | |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
21 | ||
22 | #include "btrace.h" | |
23 | #include "gdbthread.h" | |
24 | #include "exceptions.h" | |
25 | #include "inferior.h" | |
26 | #include "target.h" | |
27 | #include "record.h" | |
28 | #include "symtab.h" | |
29 | #include "disasm.h" | |
30 | #include "source.h" | |
31 | #include "filenames.h" | |
c12a2917 | 32 | #include "xml-support.h" |
02d27625 MM |
33 | |
34 | /* Print a record debug message. Use do ... while (0) to avoid ambiguities | |
35 | when used in if statements. */ | |
36 | ||
37 | #define DEBUG(msg, args...) \ | |
38 | do \ | |
39 | { \ | |
40 | if (record_debug != 0) \ | |
41 | fprintf_unfiltered (gdb_stdlog, \ | |
42 | "[btrace] " msg "\n", ##args); \ | |
43 | } \ | |
44 | while (0) | |
45 | ||
46 | #define DEBUG_FTRACE(msg, args...) DEBUG ("[ftrace] " msg, ##args) | |
47 | ||
48 | /* Initialize the instruction iterator. */ | |
49 | ||
50 | static void | |
51 | btrace_init_insn_iterator (struct btrace_thread_info *btinfo) | |
52 | { | |
53 | DEBUG ("init insn iterator"); | |
54 | ||
55 | btinfo->insn_iterator.begin = 1; | |
56 | btinfo->insn_iterator.end = 0; | |
57 | } | |
58 | ||
59 | /* Initialize the function iterator. */ | |
60 | ||
61 | static void | |
62 | btrace_init_func_iterator (struct btrace_thread_info *btinfo) | |
63 | { | |
64 | DEBUG ("init func iterator"); | |
65 | ||
66 | btinfo->func_iterator.begin = 1; | |
67 | btinfo->func_iterator.end = 0; | |
68 | } | |
69 | ||
70 | /* Compute the instruction trace from the block trace. */ | |
71 | ||
72 | static VEC (btrace_inst_s) * | |
73 | compute_itrace (VEC (btrace_block_s) *btrace) | |
74 | { | |
75 | VEC (btrace_inst_s) *itrace; | |
76 | struct gdbarch *gdbarch; | |
77 | unsigned int b; | |
78 | ||
79 | DEBUG ("compute itrace"); | |
80 | ||
81 | itrace = NULL; | |
82 | gdbarch = target_gdbarch (); | |
83 | b = VEC_length (btrace_block_s, btrace); | |
84 | ||
85 | while (b-- != 0) | |
86 | { | |
87 | btrace_block_s *block; | |
88 | CORE_ADDR pc; | |
89 | ||
90 | block = VEC_index (btrace_block_s, btrace, b); | |
91 | pc = block->begin; | |
92 | ||
93 | /* Add instructions for this block. */ | |
94 | for (;;) | |
95 | { | |
96 | btrace_inst_s *inst; | |
97 | int size; | |
98 | ||
99 | /* We should hit the end of the block. Warn if we went too far. */ | |
100 | if (block->end < pc) | |
101 | { | |
102 | warning (_("Recorded trace may be corrupted.")); | |
103 | break; | |
104 | } | |
105 | ||
106 | inst = VEC_safe_push (btrace_inst_s, itrace, NULL); | |
107 | inst->pc = pc; | |
108 | ||
109 | /* We're done once we pushed the instruction at the end. */ | |
110 | if (block->end == pc) | |
111 | break; | |
112 | ||
113 | size = gdb_insn_length (gdbarch, pc); | |
114 | ||
115 | /* Make sure we terminate if we fail to compute the size. */ | |
116 | if (size <= 0) | |
117 | { | |
118 | warning (_("Recorded trace may be incomplete.")); | |
119 | break; | |
120 | } | |
121 | ||
122 | pc += size; | |
123 | } | |
124 | } | |
125 | ||
126 | return itrace; | |
127 | } | |
128 | ||
129 | /* Return the function name of a recorded function segment for printing. | |
130 | This function never returns NULL. */ | |
131 | ||
132 | static const char * | |
133 | ftrace_print_function_name (struct btrace_func *bfun) | |
134 | { | |
135 | struct minimal_symbol *msym; | |
136 | struct symbol *sym; | |
137 | ||
138 | msym = bfun->msym; | |
139 | sym = bfun->sym; | |
140 | ||
141 | if (sym != NULL) | |
142 | return SYMBOL_PRINT_NAME (sym); | |
143 | ||
144 | if (msym != NULL) | |
145 | return SYMBOL_PRINT_NAME (msym); | |
146 | ||
147 | return "<unknown>"; | |
148 | } | |
149 | ||
150 | /* Return the file name of a recorded function segment for printing. | |
151 | This function never returns NULL. */ | |
152 | ||
153 | static const char * | |
154 | ftrace_print_filename (struct btrace_func *bfun) | |
155 | { | |
156 | struct symbol *sym; | |
157 | const char *filename; | |
158 | ||
159 | sym = bfun->sym; | |
160 | ||
161 | if (sym != NULL) | |
162 | filename = symtab_to_filename_for_display (sym->symtab); | |
163 | else | |
164 | filename = "<unknown>"; | |
165 | ||
166 | return filename; | |
167 | } | |
168 | ||
169 | /* Print an ftrace debug status message. */ | |
170 | ||
171 | static void | |
172 | ftrace_debug (struct btrace_func *bfun, const char *prefix) | |
173 | { | |
174 | DEBUG_FTRACE ("%s: fun = %s, file = %s, lines = [%d; %d], insn = [%u; %u]", | |
175 | prefix, ftrace_print_function_name (bfun), | |
176 | ftrace_print_filename (bfun), bfun->lbegin, bfun->lend, | |
177 | bfun->ibegin, bfun->iend); | |
178 | } | |
179 | ||
180 | /* Initialize a recorded function segment. */ | |
181 | ||
182 | static void | |
183 | ftrace_init_func (struct btrace_func *bfun, struct minimal_symbol *mfun, | |
184 | struct symbol *fun, unsigned int idx) | |
185 | { | |
186 | bfun->msym = mfun; | |
187 | bfun->sym = fun; | |
188 | bfun->lbegin = INT_MAX; | |
189 | bfun->lend = 0; | |
190 | bfun->ibegin = idx; | |
191 | bfun->iend = idx; | |
192 | } | |
193 | ||
194 | /* Check whether the function has changed. */ | |
195 | ||
196 | static int | |
197 | ftrace_function_switched (struct btrace_func *bfun, | |
198 | struct minimal_symbol *mfun, struct symbol *fun) | |
199 | { | |
200 | struct minimal_symbol *msym; | |
201 | struct symbol *sym; | |
202 | ||
203 | /* The function changed if we did not have one before. */ | |
204 | if (bfun == NULL) | |
205 | return 1; | |
206 | ||
207 | msym = bfun->msym; | |
208 | sym = bfun->sym; | |
209 | ||
210 | /* If the minimal symbol changed, we certainly switched functions. */ | |
211 | if (mfun != NULL && msym != NULL | |
212 | && strcmp (SYMBOL_LINKAGE_NAME (mfun), SYMBOL_LINKAGE_NAME (msym)) != 0) | |
213 | return 1; | |
214 | ||
215 | /* If the symbol changed, we certainly switched functions. */ | |
216 | if (fun != NULL && sym != NULL) | |
217 | { | |
218 | const char *bfname, *fname; | |
219 | ||
220 | /* Check the function name. */ | |
221 | if (strcmp (SYMBOL_LINKAGE_NAME (fun), SYMBOL_LINKAGE_NAME (sym)) != 0) | |
222 | return 1; | |
223 | ||
224 | /* Check the location of those functions, as well. */ | |
225 | bfname = symtab_to_fullname (sym->symtab); | |
226 | fname = symtab_to_fullname (fun->symtab); | |
227 | if (filename_cmp (fname, bfname) != 0) | |
228 | return 1; | |
229 | } | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | /* Check if we should skip this file when generating the function call | |
235 | history. We would want to do that if, say, a macro that is defined | |
236 | in another file is expanded in this function. */ | |
237 | ||
238 | static int | |
239 | ftrace_skip_file (struct btrace_func *bfun, const char *filename) | |
240 | { | |
241 | struct symbol *sym; | |
242 | const char *bfile; | |
243 | ||
244 | sym = bfun->sym; | |
245 | ||
246 | if (sym != NULL) | |
247 | bfile = symtab_to_fullname (sym->symtab); | |
248 | else | |
249 | bfile = ""; | |
250 | ||
251 | if (filename == NULL) | |
252 | filename = ""; | |
253 | ||
254 | return (filename_cmp (bfile, filename) != 0); | |
255 | } | |
256 | ||
257 | /* Compute the function trace from the instruction trace. */ | |
258 | ||
259 | static VEC (btrace_func_s) * | |
260 | compute_ftrace (VEC (btrace_inst_s) *itrace) | |
261 | { | |
262 | VEC (btrace_func_s) *ftrace; | |
263 | struct btrace_inst *binst; | |
264 | struct btrace_func *bfun; | |
265 | unsigned int idx; | |
266 | ||
267 | DEBUG ("compute ftrace"); | |
268 | ||
269 | ftrace = NULL; | |
270 | bfun = NULL; | |
271 | ||
272 | for (idx = 0; VEC_iterate (btrace_inst_s, itrace, idx, binst); ++idx) | |
273 | { | |
274 | struct symtab_and_line sal; | |
275 | struct minimal_symbol *mfun; | |
276 | struct symbol *fun; | |
277 | const char *filename; | |
278 | CORE_ADDR pc; | |
279 | ||
280 | pc = binst->pc; | |
281 | ||
282 | /* Try to determine the function we're in. We use both types of symbols | |
283 | to avoid surprises when we sometimes get a full symbol and sometimes | |
284 | only a minimal symbol. */ | |
285 | fun = find_pc_function (pc); | |
286 | mfun = lookup_minimal_symbol_by_pc (pc); | |
287 | ||
288 | if (fun == NULL && mfun == NULL) | |
289 | { | |
290 | DEBUG_FTRACE ("no symbol at %u, pc=%s", idx, | |
291 | core_addr_to_string_nz (pc)); | |
292 | continue; | |
293 | } | |
294 | ||
295 | /* If we're switching functions, we start over. */ | |
296 | if (ftrace_function_switched (bfun, mfun, fun)) | |
297 | { | |
298 | bfun = VEC_safe_push (btrace_func_s, ftrace, NULL); | |
299 | ||
300 | ftrace_init_func (bfun, mfun, fun, idx); | |
301 | ftrace_debug (bfun, "init"); | |
302 | } | |
303 | ||
304 | /* Update the instruction range. */ | |
305 | bfun->iend = idx; | |
306 | ftrace_debug (bfun, "update insns"); | |
307 | ||
308 | /* Let's see if we have source correlation, as well. */ | |
309 | sal = find_pc_line (pc, 0); | |
310 | if (sal.symtab == NULL || sal.line == 0) | |
311 | { | |
312 | DEBUG_FTRACE ("no lines at %u, pc=%s", idx, | |
313 | core_addr_to_string_nz (pc)); | |
314 | continue; | |
315 | } | |
316 | ||
317 | /* Check if we switched files. This could happen if, say, a macro that | |
318 | is defined in another file is expanded here. */ | |
319 | filename = symtab_to_fullname (sal.symtab); | |
320 | if (ftrace_skip_file (bfun, filename)) | |
321 | { | |
322 | DEBUG_FTRACE ("ignoring file at %u, pc=%s, file=%s", idx, | |
323 | core_addr_to_string_nz (pc), filename); | |
324 | continue; | |
325 | } | |
326 | ||
327 | /* Update the line range. */ | |
328 | bfun->lbegin = min (bfun->lbegin, sal.line); | |
329 | bfun->lend = max (bfun->lend, sal.line); | |
330 | ftrace_debug (bfun, "update lines"); | |
331 | } | |
332 | ||
333 | return ftrace; | |
334 | } | |
335 | ||
336 | /* See btrace.h. */ | |
337 | ||
338 | void | |
339 | btrace_enable (struct thread_info *tp) | |
340 | { | |
341 | if (tp->btrace.target != NULL) | |
342 | return; | |
343 | ||
344 | if (!target_supports_btrace ()) | |
345 | error (_("Target does not support branch tracing.")); | |
346 | ||
347 | DEBUG ("enable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid)); | |
348 | ||
349 | tp->btrace.target = target_enable_btrace (tp->ptid); | |
350 | } | |
351 | ||
352 | /* See btrace.h. */ | |
353 | ||
354 | void | |
355 | btrace_disable (struct thread_info *tp) | |
356 | { | |
357 | struct btrace_thread_info *btp = &tp->btrace; | |
358 | int errcode = 0; | |
359 | ||
360 | if (btp->target == NULL) | |
361 | return; | |
362 | ||
363 | DEBUG ("disable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid)); | |
364 | ||
365 | target_disable_btrace (btp->target); | |
366 | btp->target = NULL; | |
367 | ||
368 | btrace_clear (tp); | |
369 | } | |
370 | ||
371 | /* See btrace.h. */ | |
372 | ||
373 | void | |
374 | btrace_teardown (struct thread_info *tp) | |
375 | { | |
376 | struct btrace_thread_info *btp = &tp->btrace; | |
377 | int errcode = 0; | |
378 | ||
379 | if (btp->target == NULL) | |
380 | return; | |
381 | ||
382 | DEBUG ("teardown thread %d (%s)", tp->num, target_pid_to_str (tp->ptid)); | |
383 | ||
384 | target_teardown_btrace (btp->target); | |
385 | btp->target = NULL; | |
386 | ||
387 | btrace_clear (tp); | |
388 | } | |
389 | ||
390 | /* See btrace.h. */ | |
391 | ||
392 | void | |
393 | btrace_fetch (struct thread_info *tp) | |
394 | { | |
395 | struct btrace_thread_info *btinfo; | |
396 | VEC (btrace_block_s) *btrace; | |
397 | ||
398 | DEBUG ("fetch thread %d (%s)", tp->num, target_pid_to_str (tp->ptid)); | |
399 | ||
400 | btinfo = &tp->btrace; | |
401 | if (btinfo->target == NULL) | |
402 | return; | |
403 | ||
404 | btrace = target_read_btrace (btinfo->target, btrace_read_new); | |
405 | if (VEC_empty (btrace_block_s, btrace)) | |
406 | return; | |
407 | ||
408 | btrace_clear (tp); | |
409 | ||
410 | btinfo->btrace = btrace; | |
411 | btinfo->itrace = compute_itrace (btinfo->btrace); | |
412 | btinfo->ftrace = compute_ftrace (btinfo->itrace); | |
413 | ||
414 | /* Initialize branch trace iterators. */ | |
415 | btrace_init_insn_iterator (btinfo); | |
416 | btrace_init_func_iterator (btinfo); | |
417 | } | |
418 | ||
419 | /* See btrace.h. */ | |
420 | ||
421 | void | |
422 | btrace_clear (struct thread_info *tp) | |
423 | { | |
424 | struct btrace_thread_info *btinfo; | |
425 | ||
426 | DEBUG ("clear thread %d (%s)", tp->num, target_pid_to_str (tp->ptid)); | |
427 | ||
428 | btinfo = &tp->btrace; | |
429 | ||
430 | VEC_free (btrace_block_s, btinfo->btrace); | |
431 | VEC_free (btrace_inst_s, btinfo->itrace); | |
432 | VEC_free (btrace_func_s, btinfo->ftrace); | |
433 | ||
434 | btinfo->btrace = NULL; | |
435 | btinfo->itrace = NULL; | |
436 | btinfo->ftrace = NULL; | |
437 | } | |
438 | ||
439 | /* See btrace.h. */ | |
440 | ||
441 | void | |
442 | btrace_free_objfile (struct objfile *objfile) | |
443 | { | |
444 | struct thread_info *tp; | |
445 | ||
446 | DEBUG ("free objfile"); | |
447 | ||
448 | ALL_THREADS (tp) | |
449 | btrace_clear (tp); | |
450 | } | |
c12a2917 MM |
451 | |
452 | #if defined (HAVE_LIBEXPAT) | |
453 | ||
454 | /* Check the btrace document version. */ | |
455 | ||
456 | static void | |
457 | check_xml_btrace_version (struct gdb_xml_parser *parser, | |
458 | const struct gdb_xml_element *element, | |
459 | void *user_data, VEC (gdb_xml_value_s) *attributes) | |
460 | { | |
461 | const char *version = xml_find_attribute (attributes, "version")->value; | |
462 | ||
463 | if (strcmp (version, "1.0") != 0) | |
464 | gdb_xml_error (parser, _("Unsupported btrace version: \"%s\""), version); | |
465 | } | |
466 | ||
467 | /* Parse a btrace "block" xml record. */ | |
468 | ||
469 | static void | |
470 | parse_xml_btrace_block (struct gdb_xml_parser *parser, | |
471 | const struct gdb_xml_element *element, | |
472 | void *user_data, VEC (gdb_xml_value_s) *attributes) | |
473 | { | |
474 | VEC (btrace_block_s) **btrace; | |
475 | struct btrace_block *block; | |
476 | ULONGEST *begin, *end; | |
477 | ||
478 | btrace = user_data; | |
479 | block = VEC_safe_push (btrace_block_s, *btrace, NULL); | |
480 | ||
481 | begin = xml_find_attribute (attributes, "begin")->value; | |
482 | end = xml_find_attribute (attributes, "end")->value; | |
483 | ||
484 | block->begin = *begin; | |
485 | block->end = *end; | |
486 | } | |
487 | ||
488 | static const struct gdb_xml_attribute block_attributes[] = { | |
489 | { "begin", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, | |
490 | { "end", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL }, | |
491 | { NULL, GDB_XML_AF_NONE, NULL, NULL } | |
492 | }; | |
493 | ||
494 | static const struct gdb_xml_attribute btrace_attributes[] = { | |
495 | { "version", GDB_XML_AF_NONE, NULL, NULL }, | |
496 | { NULL, GDB_XML_AF_NONE, NULL, NULL } | |
497 | }; | |
498 | ||
499 | static const struct gdb_xml_element btrace_children[] = { | |
500 | { "block", block_attributes, NULL, | |
501 | GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL, parse_xml_btrace_block, NULL }, | |
502 | { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } | |
503 | }; | |
504 | ||
505 | static const struct gdb_xml_element btrace_elements[] = { | |
506 | { "btrace", btrace_attributes, btrace_children, GDB_XML_EF_NONE, | |
507 | check_xml_btrace_version, NULL }, | |
508 | { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL } | |
509 | }; | |
510 | ||
511 | #endif /* defined (HAVE_LIBEXPAT) */ | |
512 | ||
513 | /* See btrace.h. */ | |
514 | ||
515 | VEC (btrace_block_s) * | |
516 | parse_xml_btrace (const char *buffer) | |
517 | { | |
518 | VEC (btrace_block_s) *btrace = NULL; | |
519 | struct cleanup *cleanup; | |
520 | int errcode; | |
521 | ||
522 | #if defined (HAVE_LIBEXPAT) | |
523 | ||
524 | cleanup = make_cleanup (VEC_cleanup (btrace_block_s), &btrace); | |
525 | errcode = gdb_xml_parse_quick (_("btrace"), "btrace.dtd", btrace_elements, | |
526 | buffer, &btrace); | |
527 | if (errcode != 0) | |
528 | { | |
529 | do_cleanups (cleanup); | |
530 | return NULL; | |
531 | } | |
532 | ||
533 | /* Keep parse results. */ | |
534 | discard_cleanups (cleanup); | |
535 | ||
536 | #else /* !defined (HAVE_LIBEXPAT) */ | |
537 | ||
538 | error (_("Cannot process branch trace. XML parsing is not supported.")); | |
539 | ||
540 | #endif /* !defined (HAVE_LIBEXPAT) */ | |
541 | ||
542 | return btrace; | |
543 | } |