1 /* Inline frame unwinder for GDB.
3 Copyright (C) 2008-2019 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 symbol
*skipped_symbol_
)
41 : thread (thread_
), skipped_frames (skipped_frames_
), saved_pc (saved_pc_
),
42 skipped_symbol (skipped_symbol_
)
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 symbol
60 of the outermost skipped inline function. It's used to find the
61 call site of the current frame. */
62 struct symbol
*skipped_symbol
;
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 /* Forget about any hidden inlined functions in PTID, which is new or
99 about to be resumed. PTID may be minus_one_ptid (all processes)
100 or a PID (all threads in this process). */
103 clear_inline_frame_state (ptid_t ptid
)
105 if (ptid
== minus_one_ptid
)
107 inline_states
.clear ();
113 int pid
= ptid
.pid ();
114 auto it
= std::remove_if (inline_states
.begin (), inline_states
.end (),
115 [pid
] (const inline_state
&state
)
117 return pid
== state
.thread
->inf
->pid
;
120 inline_states
.erase (it
, inline_states
.end ());
125 auto it
= std::find_if (inline_states
.begin (), inline_states
.end (),
126 [&ptid
] (const inline_state
&state
)
128 return ptid
== state
.thread
->ptid
;
131 if (it
!= inline_states
.end ())
132 unordered_remove (inline_states
, it
);
136 inline_frame_this_id (struct frame_info
*this_frame
,
138 struct frame_id
*this_id
)
142 /* In order to have a stable frame ID for a given inline function,
143 we must get the stack / special addresses from the underlying
144 real frame's this_id method. So we must call
145 get_prev_frame_always. Because we are inlined into some
146 function, there must be previous frames, so this is safe - as
147 long as we're careful not to create any cycles. */
148 *this_id
= get_frame_id (get_prev_frame_always (this_frame
));
150 /* We need a valid frame ID, so we need to be based on a valid
151 frame. FSF submission NOTE: this would be a good assertion to
152 apply to all frames, all the time. That would fix the ambiguity
153 of null_frame_id (between "no/any frame" and "the outermost
154 frame"). This will take work. */
155 gdb_assert (frame_id_p (*this_id
));
157 /* For now, require we don't match outer_frame_id either (see
159 gdb_assert (!frame_id_eq (*this_id
, outer_frame_id
));
161 /* Future work NOTE: Alexandre Oliva applied a patch to GCC 4.3
162 which generates DW_AT_entry_pc for inlined functions when
163 possible. If this attribute is available, we should use it
164 in the frame ID (and eventually, to set breakpoints). */
165 func
= get_frame_function (this_frame
);
166 gdb_assert (func
!= NULL
);
167 (*this_id
).code_addr
= BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (func
));
168 (*this_id
).artificial_depth
++;
171 static struct value
*
172 inline_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
175 /* Use get_frame_register_value instead of
176 frame_unwind_got_register, to avoid requiring this frame's ID.
177 This frame's ID depends on the previous frame's ID (unusual), and
178 the previous frame's ID depends on this frame's unwound
179 registers. If unwinding registers from this frame called
180 get_frame_id, there would be a loop.
182 Do not copy this code into any other unwinder! Inlined functions
183 are special; other unwinders must not have a dependency on the
184 previous frame's ID, and therefore can and should use
185 frame_unwind_got_register instead. */
186 return get_frame_register_value (this_frame
, regnum
);
189 /* Check whether we are at an inlining site that does not already
190 have an associated frame. */
193 inline_frame_sniffer (const struct frame_unwind
*self
,
194 struct frame_info
*this_frame
,
198 const struct block
*frame_block
, *cur_block
;
200 struct frame_info
*next_frame
;
201 struct inline_state
*state
= find_inline_frame_state (inferior_thread ());
203 this_pc
= get_frame_address_in_block (this_frame
);
204 frame_block
= block_for_pc (this_pc
);
205 if (frame_block
== NULL
)
208 /* Calculate DEPTH, the number of inlined functions at this
211 cur_block
= frame_block
;
212 while (BLOCK_SUPERBLOCK (cur_block
))
214 if (block_inlined_p (cur_block
))
216 else if (BLOCK_FUNCTION (cur_block
) != NULL
)
219 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
222 /* Check how many inlined functions already have frames. */
223 for (next_frame
= get_next_frame (this_frame
);
224 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
225 next_frame
= get_next_frame (next_frame
))
227 gdb_assert (depth
> 0);
231 /* If this is the topmost frame, or all frames above us are inlined,
232 then check whether we were requested to skip some frames (so they
233 can be stepped into later). */
234 if (state
!= NULL
&& state
->skipped_frames
> 0 && next_frame
== NULL
)
236 gdb_assert (depth
>= state
->skipped_frames
);
237 depth
-= state
->skipped_frames
;
240 /* If all the inlined functions here already have frames, then pass
241 to the normal unwinder for this PC. */
245 /* If the next frame is an inlined function, but not the outermost, then
246 we are the next outer. If it is not an inlined function, then we
247 are the innermost inlined function of a different real frame. */
251 const struct frame_unwind inline_frame_unwind
= {
253 default_frame_unwind_stop_reason
,
254 inline_frame_this_id
,
255 inline_frame_prev_register
,
260 /* Return non-zero if BLOCK, an inlined function block containing PC,
261 has a group of contiguous instructions starting at PC (but not
265 block_starting_point_at (CORE_ADDR pc
, const struct block
*block
)
267 const struct blockvector
*bv
;
268 const struct block
*new_block
;
270 bv
= blockvector_for_pc (pc
, NULL
);
271 if (BLOCKVECTOR_MAP (bv
) == NULL
)
274 new_block
= (const struct block
*) addrmap_find (BLOCKVECTOR_MAP (bv
),
276 if (new_block
== NULL
)
279 if (new_block
== block
|| contained_in (new_block
, block
))
282 /* The immediately preceding address belongs to a different block,
283 which is not a child of this one. Treat this as an entrance into
288 /* Loop over the stop chain and determine if execution stopped in an
289 inlined frame because of a user breakpoint set at FRAME_BLOCK. */
292 stopped_by_user_bp_inline_frame (const block
*frame_block
, bpstat stop_chain
)
294 for (bpstat s
= stop_chain
; s
!= NULL
; s
= s
->next
)
296 struct breakpoint
*bpt
= s
->breakpoint_at
;
298 if (bpt
!= NULL
&& user_breakpoint_p (bpt
))
300 bp_location
*loc
= s
->bp_location_at
;
301 enum bp_loc_type t
= loc
->loc_type
;
303 if (t
== bp_loc_software_breakpoint
304 || t
== bp_loc_hardware_breakpoint
)
306 /* If the location has a function symbol, check whether
307 the frame was for that inlined function. If it has
308 no function symbol, then assume it is. I.e., default
309 to presenting the stop at the innermost inline
311 if (loc
->symbol
== nullptr
312 || frame_block
== SYMBOL_BLOCK_VALUE (loc
->symbol
))
321 /* See inline-frame.h. */
324 skip_inline_frames (thread_info
*thread
, bpstat stop_chain
)
326 const struct block
*frame_block
, *cur_block
;
327 struct symbol
*last_sym
= NULL
;
330 /* This function is called right after reinitializing the frame
331 cache. We try not to do more unwinding than absolutely
332 necessary, for performance. */
333 CORE_ADDR this_pc
= get_frame_pc (get_current_frame ());
334 frame_block
= block_for_pc (this_pc
);
336 if (frame_block
!= NULL
)
338 cur_block
= frame_block
;
339 while (BLOCK_SUPERBLOCK (cur_block
))
341 if (block_inlined_p (cur_block
))
343 /* See comments in inline_frame_this_id about this use
344 of BLOCK_ENTRY_PC. */
345 if (BLOCK_ENTRY_PC (cur_block
) == this_pc
346 || block_starting_point_at (this_pc
, cur_block
))
348 /* Do not skip the inlined frame if execution
349 stopped in an inlined frame because of a user
350 breakpoint for this inline function. */
351 if (stopped_by_user_bp_inline_frame (cur_block
, stop_chain
))
355 last_sym
= BLOCK_FUNCTION (cur_block
);
360 else if (BLOCK_FUNCTION (cur_block
) != NULL
)
363 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
367 gdb_assert (find_inline_frame_state (thread
) == NULL
);
368 inline_states
.emplace_back (thread
, skip_count
, this_pc
, last_sym
);
371 reinit_frame_cache ();
374 /* Step into an inlined function by unhiding it. */
377 step_into_inline_frame (thread_info
*thread
)
379 inline_state
*state
= find_inline_frame_state (thread
);
381 gdb_assert (state
!= NULL
&& state
->skipped_frames
> 0);
382 state
->skipped_frames
--;
383 reinit_frame_cache ();
386 /* Return the number of hidden functions inlined into the current
390 inline_skipped_frames (thread_info
*thread
)
392 inline_state
*state
= find_inline_frame_state (thread
);
397 return state
->skipped_frames
;
400 /* If one or more inlined functions are hidden, return the symbol for
401 the function inlined into the current frame. */
404 inline_skipped_symbol (thread_info
*thread
)
406 inline_state
*state
= find_inline_frame_state (thread
);
408 gdb_assert (state
!= NULL
);
409 return state
->skipped_symbol
;
412 /* Return the number of functions inlined into THIS_FRAME. Some of
413 the callees may not have associated frames (see
414 skip_inline_frames). */
417 frame_inlined_callees (struct frame_info
*this_frame
)
419 struct frame_info
*next_frame
;
420 int inline_count
= 0;
422 /* First count how many inlined functions at this PC have frames
423 above FRAME (are inlined into FRAME). */
424 for (next_frame
= get_next_frame (this_frame
);
425 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
426 next_frame
= get_next_frame (next_frame
))
429 /* Simulate some most-inner inlined frames which were suppressed, so
430 they can be stepped into later. If we are unwinding already
431 outer frames from some non-inlined frame this does not apply. */
432 if (next_frame
== NULL
)
433 inline_count
+= inline_skipped_frames (inferior_thread ());