1 /* Branch trace support for GDB, the GNU debugger.
3 Copyright (C) 2013-2015 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. */
32 #if defined (HAVE_LIBIPT)
33 # include <intel-pt.h>
37 struct btrace_function
;
39 /* A coarse instruction classification. */
40 enum btrace_insn_class
42 /* The instruction is something not listed below. */
45 /* The instruction is a function call. */
48 /* The instruction is a function return. */
51 /* The instruction is an unconditional jump. */
55 /* A branch trace instruction.
57 This represents a single instruction in a branch trace. */
60 /* The address of this instruction. */
63 /* The size of this instruction in bytes. */
66 /* The instruction class of this instruction. */
67 enum btrace_insn_class iclass
;
70 /* A vector of branch trace instructions. */
71 typedef struct btrace_insn btrace_insn_s
;
72 DEF_VEC_O (btrace_insn_s
);
74 /* A doubly-linked list of branch trace function segments. */
75 struct btrace_func_link
77 struct btrace_function
*prev
;
78 struct btrace_function
*next
;
81 /* Flags for btrace function segments. */
82 enum btrace_function_flag
84 /* The 'up' link interpretation.
85 If set, it points to the function segment we returned to.
86 If clear, it points to the function segment we called from. */
87 BFUN_UP_LINKS_TO_RET
= (1 << 0),
89 /* The 'up' link points to a tail call. This obviously only makes sense
90 if bfun_up_links_to_ret is clear. */
91 BFUN_UP_LINKS_TO_TAILCALL
= (1 << 1)
94 /* Decode errors for the BTS recording format. */
97 /* The instruction trace overflowed the end of the trace block. */
100 /* The instruction size could not be determined. */
104 /* Decode errors for the Intel(R) Processor Trace recording format. */
107 /* The user cancelled trace processing. */
108 BDE_PT_USER_QUIT
= 1,
110 /* Tracing was temporarily disabled. */
113 /* Trace recording overflowed. */
116 /* Negative numbers are used by the decoder library. */
119 /* A branch trace function segment.
121 This represents a function segment in a branch trace, i.e. a consecutive
122 number of instructions belonging to the same function.
124 In case of decode errors, we add an empty function segment to indicate
125 the gap in the trace.
127 We do not allow function segments without instructions otherwise. */
128 struct btrace_function
130 /* The full and minimal symbol for the function. Both may be NULL. */
131 struct minimal_symbol
*msym
;
134 /* The previous and next segment belonging to the same function.
135 If a function calls another function, the former will have at least
136 two segments: one before the call and another after the return. */
137 struct btrace_func_link segment
;
139 /* The previous and next function in control flow order. */
140 struct btrace_func_link flow
;
142 /* The directly preceding function segment in a (fake) call stack. */
143 struct btrace_function
*up
;
145 /* The instructions in this function segment.
146 The instruction vector will be empty if the function segment
147 represents a decode error. */
148 VEC (btrace_insn_s
) *insn
;
150 /* The error code of a decode error that led to a gap.
151 Must be zero unless INSN is empty; non-zero otherwise. */
154 /* The instruction number offset for the first instruction in this
156 If INSN is empty this is the insn_offset of the succeding function
157 segment in control-flow order. */
158 unsigned int insn_offset
;
160 /* The function number in control-flow order.
161 If INSN is empty indicating a gap in the trace due to a decode error,
162 we still count the gap as a function. */
165 /* The function level in a back trace across the entire branch trace.
166 A caller's level is one lower than the level of its callee.
168 Levels can be negative if we see returns for which we have not seen
169 the corresponding calls. The branch trace thread information provides
170 a fixup to normalize function levels so the smallest level is zero. */
173 /* A bit-vector of btrace_function_flag. */
174 enum btrace_function_flag flags
;
177 /* A branch trace instruction iterator. */
178 struct btrace_insn_iterator
180 /* The branch trace function segment containing the instruction.
181 Will never be NULL. */
182 const struct btrace_function
*function
;
184 /* The index into the function segment's instruction vector. */
188 /* A branch trace function call iterator. */
189 struct btrace_call_iterator
191 /* The branch trace information for this thread. Will never be NULL. */
192 const struct btrace_thread_info
*btinfo
;
194 /* The branch trace function segment.
195 This will be NULL for the iterator pointing to the end of the trace. */
196 const struct btrace_function
*function
;
199 /* Branch trace iteration state for "record instruction-history". */
200 struct btrace_insn_history
202 /* The branch trace instruction range from BEGIN (inclusive) to
203 END (exclusive) that has been covered last time. */
204 struct btrace_insn_iterator begin
;
205 struct btrace_insn_iterator end
;
208 /* Branch trace iteration state for "record function-call-history". */
209 struct btrace_call_history
211 /* The branch trace function range from BEGIN (inclusive) to END (exclusive)
212 that has been covered last time. */
213 struct btrace_call_iterator begin
;
214 struct btrace_call_iterator end
;
217 /* Branch trace thread flags. */
218 enum btrace_thread_flag
220 /* The thread is to be stepped forwards. */
221 BTHR_STEP
= (1 << 0),
223 /* The thread is to be stepped backwards. */
224 BTHR_RSTEP
= (1 << 1),
226 /* The thread is to be continued forwards. */
227 BTHR_CONT
= (1 << 2),
229 /* The thread is to be continued backwards. */
230 BTHR_RCONT
= (1 << 3),
232 /* The thread is to be moved. */
233 BTHR_MOVE
= (BTHR_STEP
| BTHR_RSTEP
| BTHR_CONT
| BTHR_RCONT
)
236 /* Branch trace information per thread.
238 This represents the branch trace configuration as well as the entry point
239 into the branch trace data. For the latter, it also contains the index into
240 an array of branch trace blocks used for iterating though the branch trace
241 blocks of a thread. */
242 struct btrace_thread_info
244 /* The target branch trace information for this thread.
246 This contains the branch trace configuration as well as any
247 target-specific information necessary for implementing branch tracing on
248 the underlying architecture. */
249 struct btrace_target_info
*target
;
251 /* The raw branch trace data for the below branch trace. */
252 struct btrace_data data
;
254 /* The current branch trace for this thread (both inclusive).
256 The last instruction of END is the current instruction, which is not
257 part of the execution history.
258 Both will be NULL if there is no branch trace available. If there is
259 branch trace available, both will be non-NULL. */
260 struct btrace_function
*begin
;
261 struct btrace_function
*end
;
263 /* The function level offset. When added to each function's LEVEL,
264 this normalizes the function levels such that the smallest level
268 /* The number of gaps in the trace. */
271 /* A bit-vector of btrace_thread_flag. */
272 enum btrace_thread_flag flags
;
274 /* The instruction history iterator. */
275 struct btrace_insn_history
*insn_history
;
277 /* The function call history iterator. */
278 struct btrace_call_history
*call_history
;
280 /* The current replay position. NULL if not replaying.
281 Gaps are skipped during replay, so REPLAY always points to a valid
283 struct btrace_insn_iterator
*replay
;
285 /* Why the thread stopped, if we need to track it. */
286 enum target_stop_reason stop_reason
;
289 /* Enable branch tracing for a thread. */
290 extern void btrace_enable (struct thread_info
*tp
,
291 const struct btrace_config
*conf
);
293 /* Get the branch trace configuration for a thread.
294 Return NULL if branch tracing is not enabled for that thread. */
295 extern const struct btrace_config
*
296 btrace_conf (const struct btrace_thread_info
*);
298 /* Disable branch tracing for a thread.
299 This will also delete the current branch trace data. */
300 extern void btrace_disable (struct thread_info
*);
302 /* Disable branch tracing for a thread during teardown.
303 This is similar to btrace_disable, except that it will use
304 target_teardown_btrace instead of target_disable_btrace. */
305 extern void btrace_teardown (struct thread_info
*);
307 /* Fetch the branch trace for a single thread. */
308 extern void btrace_fetch (struct thread_info
*);
310 /* Clear the branch trace for a single thread. */
311 extern void btrace_clear (struct thread_info
*);
313 /* Clear the branch trace for all threads when an object file goes away. */
314 extern void btrace_free_objfile (struct objfile
*);
316 /* Parse a branch trace xml document XML into DATA. */
317 extern void parse_xml_btrace (struct btrace_data
*data
, const char *xml
);
319 /* Parse a branch trace configuration xml document XML into CONF. */
320 extern void parse_xml_btrace_conf (struct btrace_config
*conf
, const char *xml
);
322 /* Dereference a branch trace instruction iterator. Return a pointer to the
323 instruction the iterator points to.
324 May return NULL if the iterator points to a gap in the trace. */
325 extern const struct btrace_insn
*
326 btrace_insn_get (const struct btrace_insn_iterator
*);
328 /* Return the instruction number for a branch trace iterator.
329 Returns one past the maximum instruction number for the end iterator.
330 Returns zero if the iterator does not point to a valid instruction. */
331 extern unsigned int btrace_insn_number (const struct btrace_insn_iterator
*);
333 /* Initialize a branch trace instruction iterator to point to the begin/end of
334 the branch trace. Throws an error if there is no branch trace. */
335 extern void btrace_insn_begin (struct btrace_insn_iterator
*,
336 const struct btrace_thread_info
*);
337 extern void btrace_insn_end (struct btrace_insn_iterator
*,
338 const struct btrace_thread_info
*);
340 /* Increment/decrement a branch trace instruction iterator by at most STRIDE
341 instructions. Return the number of instructions by which the instruction
342 iterator has been advanced.
343 Returns zero, if the operation failed or STRIDE had been zero. */
344 extern unsigned int btrace_insn_next (struct btrace_insn_iterator
*,
345 unsigned int stride
);
346 extern unsigned int btrace_insn_prev (struct btrace_insn_iterator
*,
347 unsigned int stride
);
349 /* Compare two branch trace instruction iterators.
350 Return a negative number if LHS < RHS.
351 Return zero if LHS == RHS.
352 Return a positive number if LHS > RHS. */
353 extern int btrace_insn_cmp (const struct btrace_insn_iterator
*lhs
,
354 const struct btrace_insn_iterator
*rhs
);
356 /* Find an instruction in the function branch trace by its number.
357 If the instruction is found, initialize the branch trace instruction
358 iterator to point to this instruction and return non-zero.
359 Return zero otherwise. */
360 extern int btrace_find_insn_by_number (struct btrace_insn_iterator
*,
361 const struct btrace_thread_info
*,
362 unsigned int number
);
364 /* Dereference a branch trace call iterator. Return a pointer to the
365 function the iterator points to or NULL if the interator points past
366 the end of the branch trace. */
367 extern const struct btrace_function
*
368 btrace_call_get (const struct btrace_call_iterator
*);
370 /* Return the function number for a branch trace call iterator.
371 Returns one past the maximum function number for the end iterator.
372 Returns zero if the iterator does not point to a valid function. */
373 extern unsigned int btrace_call_number (const struct btrace_call_iterator
*);
375 /* Initialize a branch trace call iterator to point to the begin/end of
376 the branch trace. Throws an error if there is no branch trace. */
377 extern void btrace_call_begin (struct btrace_call_iterator
*,
378 const struct btrace_thread_info
*);
379 extern void btrace_call_end (struct btrace_call_iterator
*,
380 const struct btrace_thread_info
*);
382 /* Increment/decrement a branch trace call iterator by at most STRIDE function
383 segments. Return the number of function segments by which the call
384 iterator has been advanced.
385 Returns zero, if the operation failed or STRIDE had been zero. */
386 extern unsigned int btrace_call_next (struct btrace_call_iterator
*,
387 unsigned int stride
);
388 extern unsigned int btrace_call_prev (struct btrace_call_iterator
*,
389 unsigned int stride
);
391 /* Compare two branch trace call iterators.
392 Return a negative number if LHS < RHS.
393 Return zero if LHS == RHS.
394 Return a positive number if LHS > RHS. */
395 extern int btrace_call_cmp (const struct btrace_call_iterator
*lhs
,
396 const struct btrace_call_iterator
*rhs
);
398 /* Find a function in the function branch trace by its NUMBER.
399 If the function is found, initialize the branch trace call
400 iterator to point to this function and return non-zero.
401 Return zero otherwise. */
402 extern int btrace_find_call_by_number (struct btrace_call_iterator
*,
403 const struct btrace_thread_info
*,
404 unsigned int number
);
406 /* Set the branch trace instruction history from BEGIN (inclusive) to
408 extern void btrace_set_insn_history (struct btrace_thread_info
*,
409 const struct btrace_insn_iterator
*begin
,
410 const struct btrace_insn_iterator
*end
);
412 /* Set the branch trace function call history from BEGIN (inclusive) to
414 extern void btrace_set_call_history (struct btrace_thread_info
*,
415 const struct btrace_call_iterator
*begin
,
416 const struct btrace_call_iterator
*end
);
418 /* Determine if branch tracing is currently replaying TP. */
419 extern int btrace_is_replaying (struct thread_info
*tp
);
421 /* Return non-zero if the branch trace for TP is empty; zero otherwise. */
422 extern int btrace_is_empty (struct thread_info
*tp
);
424 /* Create a cleanup for DATA. */
425 extern struct cleanup
*make_cleanup_btrace_data (struct btrace_data
*data
);
427 #endif /* BTRACE_H */