1 /* Inline frame unwinder for GDB.
3 Copyright (C) 2008-2021 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #include "breakpoint.h"
22 #include "inline-frame.h"
25 #include "frame-unwind.h"
27 #include "gdbthread.h"
33 /* We need to save a few variables for every thread stopped at the
34 virtual call site of an inlined function. If there was always a
35 "struct thread_info", we could hang it off that; in the mean time,
39 inline_state (thread_info
*thread_
, int skipped_frames_
, CORE_ADDR saved_pc_
,
40 std::vector
<symbol
*> &&skipped_symbols_
)
41 : thread (thread_
), skipped_frames (skipped_frames_
), saved_pc (saved_pc_
),
42 skipped_symbols (std::move (skipped_symbols_
))
45 /* The thread this data relates to. It should be a currently
49 /* The number of inlined functions we are skipping. Each of these
50 functions can be stepped in to. */
53 /* Only valid if SKIPPED_FRAMES is non-zero. This is the PC used
54 when calculating SKIPPED_FRAMES; used to check whether we have
55 moved to a new location by user request. If so, we invalidate
56 any skipped frames. */
59 /* Only valid if SKIPPED_FRAMES is non-zero. This is the list of all
60 function symbols that have been skipped, from inner most to outer
61 most. It is used to find the call site of the current frame. */
62 std::vector
<struct symbol
*> skipped_symbols
;
65 static std::vector
<inline_state
> inline_states
;
67 /* Locate saved inlined frame state for THREAD, if it exists and is
70 static struct inline_state
*
71 find_inline_frame_state (thread_info
*thread
)
73 auto state_it
= std::find_if (inline_states
.begin (), inline_states
.end (),
74 [thread
] (const inline_state
&state
)
76 return state
.thread
== thread
;
79 if (state_it
== inline_states
.end ())
82 inline_state
&state
= *state_it
;
83 struct regcache
*regcache
= get_thread_regcache (thread
);
84 CORE_ADDR current_pc
= regcache_read_pc (regcache
);
86 if (current_pc
!= state
.saved_pc
)
88 /* PC has changed - this context is invalid. Use the
91 unordered_remove (inline_states
, state_it
);
98 /* See inline-frame.h. */
101 clear_inline_frame_state (process_stratum_target
*target
, ptid_t filter_ptid
)
103 gdb_assert (target
!= NULL
);
105 if (filter_ptid
== minus_one_ptid
|| filter_ptid
.is_pid ())
107 auto matcher
= [target
, &filter_ptid
] (const inline_state
&state
)
109 thread_info
*t
= state
.thread
;
110 return (t
->inf
->process_target () == target
111 && t
->ptid
.matches (filter_ptid
));
114 auto it
= std::remove_if (inline_states
.begin (), inline_states
.end (),
117 inline_states
.erase (it
, inline_states
.end ());
123 auto matcher
= [target
, &filter_ptid
] (const inline_state
&state
)
125 thread_info
*t
= state
.thread
;
126 return (t
->inf
->process_target () == target
127 && filter_ptid
== t
->ptid
);
130 auto it
= std::find_if (inline_states
.begin (), inline_states
.end (),
133 if (it
!= inline_states
.end ())
134 unordered_remove (inline_states
, it
);
137 /* See inline-frame.h. */
140 clear_inline_frame_state (thread_info
*thread
)
142 auto it
= std::find_if (inline_states
.begin (), inline_states
.end (),
143 [thread
] (const inline_state
&state
)
145 return thread
== state
.thread
;
148 if (it
!= inline_states
.end ())
149 unordered_remove (inline_states
, it
);
153 inline_frame_this_id (struct frame_info
*this_frame
,
155 struct frame_id
*this_id
)
159 /* In order to have a stable frame ID for a given inline function,
160 we must get the stack / special addresses from the underlying
161 real frame's this_id method. So we must call
162 get_prev_frame_always. Because we are inlined into some
163 function, there must be previous frames, so this is safe - as
164 long as we're careful not to create any cycles. See related
165 comments in get_prev_frame_always_1. */
166 frame_info
*prev_frame
= get_prev_frame_always (this_frame
);
167 if (prev_frame
== nullptr)
168 error (_("failed to find previous frame when computing inline frame id"));
169 *this_id
= get_frame_id (prev_frame
);
171 /* We need a valid frame ID, so we need to be based on a valid
172 frame. FSF submission NOTE: this would be a good assertion to
173 apply to all frames, all the time. That would fix the ambiguity
174 of null_frame_id (between "no/any frame" and "the outermost
175 frame"). This will take work. */
176 gdb_assert (frame_id_p (*this_id
));
178 /* Future work NOTE: Alexandre Oliva applied a patch to GCC 4.3
179 which generates DW_AT_entry_pc for inlined functions when
180 possible. If this attribute is available, we should use it
181 in the frame ID (and eventually, to set breakpoints). */
182 func
= get_frame_function (this_frame
);
183 gdb_assert (func
!= NULL
);
184 (*this_id
).code_addr
= BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (func
));
185 (*this_id
).artificial_depth
++;
188 static struct value
*
189 inline_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
192 /* Use get_frame_register_value instead of
193 frame_unwind_got_register, to avoid requiring this frame's ID.
194 This frame's ID depends on the previous frame's ID (unusual), and
195 the previous frame's ID depends on this frame's unwound
196 registers. If unwinding registers from this frame called
197 get_frame_id, there would be a loop.
199 Do not copy this code into any other unwinder! Inlined functions
200 are special; other unwinders must not have a dependency on the
201 previous frame's ID, and therefore can and should use
202 frame_unwind_got_register instead. */
203 return get_frame_register_value (this_frame
, regnum
);
206 /* Check whether we are at an inlining site that does not already
207 have an associated frame. */
210 inline_frame_sniffer (const struct frame_unwind
*self
,
211 struct frame_info
*this_frame
,
215 const struct block
*frame_block
, *cur_block
;
217 struct frame_info
*next_frame
;
218 struct inline_state
*state
= find_inline_frame_state (inferior_thread ());
220 this_pc
= get_frame_address_in_block (this_frame
);
221 frame_block
= block_for_pc (this_pc
);
222 if (frame_block
== NULL
)
225 /* Calculate DEPTH, the number of inlined functions at this
228 cur_block
= frame_block
;
229 while (BLOCK_SUPERBLOCK (cur_block
))
231 if (block_inlined_p (cur_block
))
233 else if (BLOCK_FUNCTION (cur_block
) != NULL
)
236 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
239 /* Check how many inlined functions already have frames. */
240 for (next_frame
= get_next_frame (this_frame
);
241 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
242 next_frame
= get_next_frame (next_frame
))
244 gdb_assert (depth
> 0);
248 /* If this is the topmost frame, or all frames above us are inlined,
249 then check whether we were requested to skip some frames (so they
250 can be stepped into later). */
251 if (state
!= NULL
&& state
->skipped_frames
> 0 && next_frame
== NULL
)
253 gdb_assert (depth
>= state
->skipped_frames
);
254 depth
-= state
->skipped_frames
;
257 /* If all the inlined functions here already have frames, then pass
258 to the normal unwinder for this PC. */
262 /* If the next frame is an inlined function, but not the outermost, then
263 we are the next outer. If it is not an inlined function, then we
264 are the innermost inlined function of a different real frame. */
268 const struct frame_unwind inline_frame_unwind
= {
271 default_frame_unwind_stop_reason
,
272 inline_frame_this_id
,
273 inline_frame_prev_register
,
278 /* Return non-zero if BLOCK, an inlined function block containing PC,
279 has a group of contiguous instructions starting at PC (but not
283 block_starting_point_at (CORE_ADDR pc
, const struct block
*block
)
285 const struct blockvector
*bv
;
286 const struct block
*new_block
;
288 bv
= blockvector_for_pc (pc
, NULL
);
289 if (BLOCKVECTOR_MAP (bv
) == NULL
)
292 new_block
= (const struct block
*) addrmap_find (BLOCKVECTOR_MAP (bv
),
294 if (new_block
== NULL
)
297 if (new_block
== block
|| contained_in (new_block
, block
))
300 /* The immediately preceding address belongs to a different block,
301 which is not a child of this one. Treat this as an entrance into
306 /* Loop over the stop chain and determine if execution stopped in an
307 inlined frame because of a breakpoint with a user-specified location
308 set at FRAME_BLOCK. */
311 stopped_by_user_bp_inline_frame (const block
*frame_block
, bpstat stop_chain
)
313 for (bpstat s
= stop_chain
; s
!= NULL
; s
= s
->next
)
315 struct breakpoint
*bpt
= s
->breakpoint_at
;
318 && (user_breakpoint_p (bpt
) || bpt
->type
== bp_until
))
320 bp_location
*loc
= s
->bp_location_at
.get ();
321 enum bp_loc_type t
= loc
->loc_type
;
323 if (t
== bp_loc_software_breakpoint
324 || t
== bp_loc_hardware_breakpoint
)
326 /* If the location has a function symbol, check whether
327 the frame was for that inlined function. If it has
328 no function symbol, then assume it is. I.e., default
329 to presenting the stop at the innermost inline
331 if (loc
->symbol
== nullptr
332 || frame_block
== SYMBOL_BLOCK_VALUE (loc
->symbol
))
341 /* See inline-frame.h. */
344 skip_inline_frames (thread_info
*thread
, bpstat stop_chain
)
346 const struct block
*frame_block
, *cur_block
;
347 std::vector
<struct symbol
*> skipped_syms
;
350 /* This function is called right after reinitializing the frame
351 cache. We try not to do more unwinding than absolutely
352 necessary, for performance. */
353 CORE_ADDR this_pc
= get_frame_pc (get_current_frame ());
354 frame_block
= block_for_pc (this_pc
);
356 if (frame_block
!= NULL
)
358 cur_block
= frame_block
;
359 while (BLOCK_SUPERBLOCK (cur_block
))
361 if (block_inlined_p (cur_block
))
363 /* See comments in inline_frame_this_id about this use
364 of BLOCK_ENTRY_PC. */
365 if (BLOCK_ENTRY_PC (cur_block
) == this_pc
366 || block_starting_point_at (this_pc
, cur_block
))
368 /* Do not skip the inlined frame if execution
369 stopped in an inlined frame because of a user
370 breakpoint for this inline function. */
371 if (stopped_by_user_bp_inline_frame (cur_block
, stop_chain
))
375 skipped_syms
.push_back (BLOCK_FUNCTION (cur_block
));
380 else if (BLOCK_FUNCTION (cur_block
) != NULL
)
383 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
387 gdb_assert (find_inline_frame_state (thread
) == NULL
);
388 inline_states
.emplace_back (thread
, skip_count
, this_pc
,
389 std::move (skipped_syms
));
392 reinit_frame_cache ();
395 /* Step into an inlined function by unhiding it. */
398 step_into_inline_frame (thread_info
*thread
)
400 inline_state
*state
= find_inline_frame_state (thread
);
402 gdb_assert (state
!= NULL
&& state
->skipped_frames
> 0);
403 state
->skipped_frames
--;
404 reinit_frame_cache ();
407 /* Return the number of hidden functions inlined into the current
411 inline_skipped_frames (thread_info
*thread
)
413 inline_state
*state
= find_inline_frame_state (thread
);
418 return state
->skipped_frames
;
421 /* If one or more inlined functions are hidden, return the symbol for
422 the function inlined into the current frame. */
425 inline_skipped_symbol (thread_info
*thread
)
427 inline_state
*state
= find_inline_frame_state (thread
);
428 gdb_assert (state
!= NULL
);
430 /* This should only be called when we are skipping at least one frame,
431 hence SKIPPED_FRAMES will be greater than zero when we get here.
432 We initialise SKIPPED_FRAMES at the same time as we build
433 SKIPPED_SYMBOLS, hence it should be true that SKIPPED_FRAMES never
434 indexes outside of the SKIPPED_SYMBOLS vector. */
435 gdb_assert (state
->skipped_frames
> 0);
436 gdb_assert (state
->skipped_frames
<= state
->skipped_symbols
.size ());
437 return state
->skipped_symbols
[state
->skipped_frames
- 1];
440 /* Return the number of functions inlined into THIS_FRAME. Some of
441 the callees may not have associated frames (see
442 skip_inline_frames). */
445 frame_inlined_callees (struct frame_info
*this_frame
)
447 struct frame_info
*next_frame
;
448 int inline_count
= 0;
450 /* First count how many inlined functions at this PC have frames
451 above FRAME (are inlined into FRAME). */
452 for (next_frame
= get_next_frame (this_frame
);
453 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
454 next_frame
= get_next_frame (next_frame
))
457 /* Simulate some most-inner inlined frames which were suppressed, so
458 they can be stepped into later. If we are unwinding already
459 outer frames from some non-inlined frame this does not apply. */
460 if (next_frame
== NULL
)
461 inline_count
+= inline_skipped_frames (inferior_thread ());