1 /* Branch trace support for GDB, the GNU debugger.
3 Copyright (C) 2013-2017 Free Software Foundation, Inc.
5 Contributed by Intel Corp. <markus.t.metzger@intel.com>.
7 This file is part of GDB.
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.
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.
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/>. */
25 /* Branch tracing (btrace) is a per-thread control-flow execution trace of the
26 inferior. For presentation purposes, the branch trace is represented as a
27 list of sequential control-flow blocks, one such list per thread. */
29 #include "btrace-common.h"
30 #include "target/waitstatus.h" /* For enum target_stop_reason. */
31 #include "common/enum-flags.h"
33 #if defined (HAVE_LIBIPT)
34 # include <intel-pt.h>
40 struct btrace_function;
42 /* A coarse instruction classification. */
43 enum btrace_insn_class
45 /* The instruction is something not listed below. */
48 /* The instruction is a function call. */
51 /* The instruction is a function return. */
54 /* The instruction is an unconditional jump. */
58 /* Instruction flags. */
61 /* The instruction has been executed speculatively. */
62 BTRACE_INSN_FLAG_SPECULATIVE = (1 << 0)
64 DEF_ENUM_FLAGS_TYPE (enum btrace_insn_flag, btrace_insn_flags);
66 /* A branch trace instruction.
68 This represents a single instruction in a branch trace. */
71 /* The address of this instruction. */
74 /* The size of this instruction in bytes. */
77 /* The instruction class of this instruction. */
78 enum btrace_insn_class iclass;
80 /* A bit vector of BTRACE_INSN_FLAGS. */
81 btrace_insn_flags flags;
84 /* A vector of branch trace instructions. */
85 typedef struct btrace_insn btrace_insn_s;
86 DEF_VEC_O (btrace_insn_s);
88 /* A doubly-linked list of branch trace function segments. */
89 struct btrace_func_link
91 struct btrace_function *prev;
92 struct btrace_function *next;
95 /* Flags for btrace function segments. */
96 enum btrace_function_flag
98 /* The 'up' link interpretation.
99 If set, it points to the function segment we returned to.
100 If clear, it points to the function segment we called from. */
101 BFUN_UP_LINKS_TO_RET = (1 << 0),
103 /* The 'up' link points to a tail call. This obviously only makes sense
104 if bfun_up_links_to_ret is clear. */
105 BFUN_UP_LINKS_TO_TAILCALL = (1 << 1)
107 DEF_ENUM_FLAGS_TYPE (enum btrace_function_flag, btrace_function_flags);
109 /* Decode errors for the BTS recording format. */
110 enum btrace_bts_error
112 /* The instruction trace overflowed the end of the trace block. */
113 BDE_BTS_OVERFLOW = 1,
115 /* The instruction size could not be determined. */
119 /* Decode errors for the Intel Processor Trace recording format. */
122 /* The user cancelled trace processing. */
123 BDE_PT_USER_QUIT = 1,
125 /* Tracing was temporarily disabled. */
128 /* Trace recording overflowed. */
131 /* Negative numbers are used by the decoder library. */
134 /* A branch trace function segment.
136 This represents a function segment in a branch trace, i.e. a consecutive
137 number of instructions belonging to the same function.
139 In case of decode errors, we add an empty function segment to indicate
140 the gap in the trace.
142 We do not allow function segments without instructions otherwise. */
143 struct btrace_function
145 /* The full and minimal symbol for the function. Both may be NULL. */
146 struct minimal_symbol *msym;
149 /* The previous and next segment belonging to the same function.
150 If a function calls another function, the former will have at least
151 two segments: one before the call and another after the return. */
152 struct btrace_func_link segment;
154 /* The function segment number of the directly preceding function segment in
155 a (fake) call stack. Will be zero if there is no such function segment in
159 /* The instructions in this function segment.
160 The instruction vector will be empty if the function segment
161 represents a decode error. */
162 VEC (btrace_insn_s) *insn;
164 /* The error code of a decode error that led to a gap.
165 Must be zero unless INSN is empty; non-zero otherwise. */
168 /* The instruction number offset for the first instruction in this
170 If INSN is empty this is the insn_offset of the succeding function
171 segment in control-flow order. */
172 unsigned int insn_offset;
174 /* The 1-based function number in control-flow order.
175 If INSN is empty indicating a gap in the trace due to a decode error,
176 we still count the gap as a function. */
179 /* The function level in a back trace across the entire branch trace.
180 A caller's level is one lower than the level of its callee.
182 Levels can be negative if we see returns for which we have not seen
183 the corresponding calls. The branch trace thread information provides
184 a fixup to normalize function levels so the smallest level is zero. */
187 /* A bit-vector of btrace_function_flag. */
188 btrace_function_flags flags;
191 /* A branch trace instruction iterator. */
192 struct btrace_insn_iterator
194 /* The branch trace information for this thread. Will never be NULL. */
195 const struct btrace_thread_info *btinfo;
197 /* The index of the function segment in BTINFO->FUNCTIONS. */
198 unsigned int call_index;
200 /* The index into the function segment's instruction vector. */
201 unsigned int insn_index;
204 /* A branch trace function call iterator. */
205 struct btrace_call_iterator
207 /* The branch trace information for this thread. Will never be NULL. */
208 const struct btrace_thread_info *btinfo;
210 /* The index of the function segment in BTINFO->FUNCTIONS. */
214 /* Branch trace iteration state for "record instruction-history". */
215 struct btrace_insn_history
217 /* The branch trace instruction range from BEGIN (inclusive) to
218 END (exclusive) that has been covered last time. */
219 struct btrace_insn_iterator begin;
220 struct btrace_insn_iterator end;
223 /* Branch trace iteration state for "record function-call-history". */
224 struct btrace_call_history
226 /* The branch trace function range from BEGIN (inclusive) to END (exclusive)
227 that has been covered last time. */
228 struct btrace_call_iterator begin;
229 struct btrace_call_iterator end;
232 /* Branch trace thread flags. */
233 enum btrace_thread_flag
235 /* The thread is to be stepped forwards. */
236 BTHR_STEP = (1 << 0),
238 /* The thread is to be stepped backwards. */
239 BTHR_RSTEP = (1 << 1),
241 /* The thread is to be continued forwards. */
242 BTHR_CONT = (1 << 2),
244 /* The thread is to be continued backwards. */
245 BTHR_RCONT = (1 << 3),
247 /* The thread is to be moved. */
248 BTHR_MOVE = (BTHR_STEP | BTHR_RSTEP | BTHR_CONT | BTHR_RCONT),
250 /* The thread is to be stopped. */
253 DEF_ENUM_FLAGS_TYPE (enum btrace_thread_flag, btrace_thread_flags);
255 #if defined (HAVE_LIBIPT)
257 struct btrace_pt_packet
259 /* The offset in the trace stream. */
262 /* The decode error code. */
263 enum pt_error_code errcode;
265 /* The decoded packet. Only valid if ERRCODE == pte_ok. */
266 struct pt_packet packet;
269 /* Define functions operating on a vector of packets. */
270 typedef struct btrace_pt_packet btrace_pt_packet_s;
271 DEF_VEC_O (btrace_pt_packet_s);
272 #endif /* defined (HAVE_LIBIPT) */
274 /* Branch trace iteration state for "maintenance btrace packet-history". */
275 struct btrace_maint_packet_history
277 /* The branch trace packet range from BEGIN (inclusive) to
278 END (exclusive) that has been covered last time. */
283 /* Branch trace maintenance information per thread.
285 This information is used by "maintenance btrace" commands. */
286 struct btrace_maint_info
288 /* Most information is format-specific.
289 The format can be found in the BTRACE.DATA.FORMAT field of each thread. */
292 /* BTRACE.DATA.FORMAT == BTRACE_FORMAT_BTS */
295 /* The packet history iterator.
296 We are iterating over BTRACE.DATA.FORMAT.VARIANT.BTS.BLOCKS. */
297 struct btrace_maint_packet_history packet_history;
300 #if defined (HAVE_LIBIPT)
301 /* BTRACE.DATA.FORMAT == BTRACE_FORMAT_PT */
304 /* A vector of decoded packets. */
305 VEC (btrace_pt_packet_s) *packets;
307 /* The packet history iterator.
308 We are iterating over the above PACKETS vector. */
309 struct btrace_maint_packet_history packet_history;
311 #endif /* defined (HAVE_LIBIPT) */
315 /* Branch trace information per thread.
317 This represents the branch trace configuration as well as the entry point
318 into the branch trace data. For the latter, it also contains the index into
319 an array of branch trace blocks used for iterating though the branch trace
320 blocks of a thread. */
321 struct btrace_thread_info
323 /* The target branch trace information for this thread.
325 This contains the branch trace configuration as well as any
326 target-specific information necessary for implementing branch tracing on
327 the underlying architecture. */
328 struct btrace_target_info *target;
330 /* The raw branch trace data for the below branch trace. */
331 struct btrace_data data;
333 /* Vector of pointer to decoded function segments in execution flow order.
334 Note that the numbering for btrace function segments starts with 1, so
335 function segment i will be at index (i - 1). */
336 std::vector<btrace_function *> functions;
338 /* The function level offset. When added to each function's LEVEL,
339 this normalizes the function levels such that the smallest level
343 /* The number of gaps in the trace. */
346 /* A bit-vector of btrace_thread_flag. */
347 btrace_thread_flags flags;
349 /* The instruction history iterator. */
350 struct btrace_insn_history *insn_history;
352 /* The function call history iterator. */
353 struct btrace_call_history *call_history;
355 /* The current replay position. NULL if not replaying.
356 Gaps are skipped during replay, so REPLAY always points to a valid
358 struct btrace_insn_iterator *replay;
360 /* Why the thread stopped, if we need to track it. */
361 enum target_stop_reason stop_reason;
363 /* Maintenance information. */
364 struct btrace_maint_info maint;
367 /* Enable branch tracing for a thread. */
368 extern void btrace_enable (struct thread_info *tp,
369 const struct btrace_config *conf);
371 /* Get the branch trace configuration for a thread.
372 Return NULL if branch tracing is not enabled for that thread. */
373 extern const struct btrace_config *
374 btrace_conf (const struct btrace_thread_info *);
376 /* Disable branch tracing for a thread.
377 This will also delete the current branch trace data. */
378 extern void btrace_disable (struct thread_info *);
380 /* Disable branch tracing for a thread during teardown.
381 This is similar to btrace_disable, except that it will use
382 target_teardown_btrace instead of target_disable_btrace. */
383 extern void btrace_teardown (struct thread_info *);
385 /* Return a human readable error string for the given ERRCODE in FORMAT.
386 The pointer will never be NULL and must not be freed. */
388 extern const char *btrace_decode_error (enum btrace_format format, int errcode);
390 /* Fetch the branch trace for a single thread. */
391 extern void btrace_fetch (struct thread_info *);
393 /* Clear the branch trace for a single thread. */
394 extern void btrace_clear (struct thread_info *);
396 /* Clear the branch trace for all threads when an object file goes away. */
397 extern void btrace_free_objfile (struct objfile *);
399 /* Parse a branch trace xml document XML into DATA. */
400 extern void parse_xml_btrace (struct btrace_data *data, const char *xml);
402 /* Parse a branch trace configuration xml document XML into CONF. */
403 extern void parse_xml_btrace_conf (struct btrace_config *conf, const char *xml);
405 /* Dereference a branch trace instruction iterator. Return a pointer to the
406 instruction the iterator points to.
407 May return NULL if the iterator points to a gap in the trace. */
408 extern const struct btrace_insn *
409 btrace_insn_get (const struct btrace_insn_iterator *);
411 /* Return the error code for a branch trace instruction iterator. Returns zero
412 if there is no error, i.e. the instruction is valid. */
413 extern int btrace_insn_get_error (const struct btrace_insn_iterator *);
415 /* Return the instruction number for a branch trace iterator.
416 Returns one past the maximum instruction number for the end iterator. */
417 extern unsigned int btrace_insn_number (const struct btrace_insn_iterator *);
419 /* Initialize a branch trace instruction iterator to point to the begin/end of
420 the branch trace. Throws an error if there is no branch trace. */
421 extern void btrace_insn_begin (struct btrace_insn_iterator *,
422 const struct btrace_thread_info *);
423 extern void btrace_insn_end (struct btrace_insn_iterator *,
424 const struct btrace_thread_info *);
426 /* Increment/decrement a branch trace instruction iterator by at most STRIDE
427 instructions. Return the number of instructions by which the instruction
428 iterator has been advanced.
429 Returns zero, if the operation failed or STRIDE had been zero. */
430 extern unsigned int btrace_insn_next (struct btrace_insn_iterator *,
431 unsigned int stride);
432 extern unsigned int btrace_insn_prev (struct btrace_insn_iterator *,
433 unsigned int stride);
435 /* Compare two branch trace instruction iterators.
436 Return a negative number if LHS < RHS.
437 Return zero if LHS == RHS.
438 Return a positive number if LHS > RHS. */
439 extern int btrace_insn_cmp (const struct btrace_insn_iterator *lhs,
440 const struct btrace_insn_iterator *rhs);
442 /* Find an instruction or gap in the function branch trace by its number.
443 If the instruction is found, initialize the branch trace instruction
444 iterator to point to this instruction and return non-zero.
445 Return zero otherwise. */
446 extern int btrace_find_insn_by_number (struct btrace_insn_iterator *,
447 const struct btrace_thread_info *,
448 unsigned int number);
450 /* Dereference a branch trace call iterator. Return a pointer to the
451 function the iterator points to or NULL if the interator points past
452 the end of the branch trace. */
453 extern const struct btrace_function *
454 btrace_call_get (const struct btrace_call_iterator *);
456 /* Return the function number for a branch trace call iterator.
457 Returns one past the maximum function number for the end iterator.
458 Returns zero if the iterator does not point to a valid function. */
459 extern unsigned int btrace_call_number (const struct btrace_call_iterator *);
461 /* Initialize a branch trace call iterator to point to the begin/end of
462 the branch trace. Throws an error if there is no branch trace. */
463 extern void btrace_call_begin (struct btrace_call_iterator *,
464 const struct btrace_thread_info *);
465 extern void btrace_call_end (struct btrace_call_iterator *,
466 const struct btrace_thread_info *);
468 /* Increment/decrement a branch trace call iterator by at most STRIDE function
469 segments. Return the number of function segments by which the call
470 iterator has been advanced.
471 Returns zero, if the operation failed or STRIDE had been zero. */
472 extern unsigned int btrace_call_next (struct btrace_call_iterator *,
473 unsigned int stride);
474 extern unsigned int btrace_call_prev (struct btrace_call_iterator *,
475 unsigned int stride);
477 /* Compare two branch trace call iterators.
478 Return a negative number if LHS < RHS.
479 Return zero if LHS == RHS.
480 Return a positive number if LHS > RHS. */
481 extern int btrace_call_cmp (const struct btrace_call_iterator *lhs,
482 const struct btrace_call_iterator *rhs);
484 /* Find a function in the function branch trace by its NUMBER.
485 If the function is found, initialize the branch trace call
486 iterator to point to this function and return non-zero.
487 Return zero otherwise. */
488 extern int btrace_find_call_by_number (struct btrace_call_iterator *,
489 const struct btrace_thread_info *,
490 unsigned int number);
492 /* Set the branch trace instruction history from BEGIN (inclusive) to
494 extern void btrace_set_insn_history (struct btrace_thread_info *,
495 const struct btrace_insn_iterator *begin,
496 const struct btrace_insn_iterator *end);
498 /* Set the branch trace function call history from BEGIN (inclusive) to
500 extern void btrace_set_call_history (struct btrace_thread_info *,
501 const struct btrace_call_iterator *begin,
502 const struct btrace_call_iterator *end);
504 /* Determine if branch tracing is currently replaying TP. */
505 extern int btrace_is_replaying (struct thread_info *tp);
507 /* Return non-zero if the branch trace for TP is empty; zero otherwise. */
508 extern int btrace_is_empty (struct thread_info *tp);
510 /* Create a cleanup for DATA. */
511 extern struct cleanup *make_cleanup_btrace_data (struct btrace_data *data);
513 #endif /* BTRACE_H */