1 /* Inline frame unwinder for GDB.
3 Copyright (C) 2008-2018 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 "inline-frame.h"
24 #include "frame-unwind.h"
32 /* We need to save a few variables for every thread stopped at the
33 virtual call site of an inlined function. If there was always a
34 "struct thread_info", we could hang it off that; in the mean time,
38 inline_state (ptid_t ptid_
, int skipped_frames_
, CORE_ADDR saved_pc_
,
39 symbol
*skipped_symbol_
)
40 : ptid (ptid_
), skipped_frames (skipped_frames_
), saved_pc (saved_pc_
),
41 skipped_symbol (skipped_symbol_
)
44 /* The thread this data relates to. It should be a currently
45 stopped thread; we assume thread IDs never change while the
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 PTID, if it exists
70 static struct inline_state
*
71 find_inline_frame_state (ptid_t ptid
)
73 auto state_it
= std::find_if (inline_states
.begin (), inline_states
.end (),
74 [&ptid
] (const inline_state
&state
)
76 return ptid
== state
.ptid
;
79 if (state_it
== inline_states
.end ())
82 inline_state
&state
= *state_it
;
83 struct regcache
*regcache
= get_thread_regcache (ptid
);
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
.ptid
.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
.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_START (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_ptid
);
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 struct block
*new_block
;
270 bv
= blockvector_for_pc (pc
, NULL
);
271 if (BLOCKVECTOR_MAP (bv
) == NULL
)
274 new_block
= (struct block
*) addrmap_find (BLOCKVECTOR_MAP (bv
), pc
- 1);
275 if (new_block
== NULL
)
278 if (new_block
== block
|| contained_in (new_block
, block
))
281 /* The immediately preceding address belongs to a different block,
282 which is not a child of this one. Treat this as an entrance into
287 /* Skip all inlined functions whose call sites are at the current PC.
288 Frames for the hidden functions will not appear in the backtrace until the
289 user steps into them. */
292 skip_inline_frames (ptid_t ptid
)
294 const struct block
*frame_block
, *cur_block
;
295 struct symbol
*last_sym
= NULL
;
298 /* This function is called right after reinitializing the frame
299 cache. We try not to do more unwinding than absolutely
300 necessary, for performance. */
301 CORE_ADDR this_pc
= get_frame_pc (get_current_frame ());
302 frame_block
= block_for_pc (this_pc
);
304 if (frame_block
!= NULL
)
306 cur_block
= frame_block
;
307 while (BLOCK_SUPERBLOCK (cur_block
))
309 if (block_inlined_p (cur_block
))
311 /* See comments in inline_frame_this_id about this use
313 if (BLOCK_START (cur_block
) == this_pc
314 || block_starting_point_at (this_pc
, cur_block
))
317 last_sym
= BLOCK_FUNCTION (cur_block
);
322 else if (BLOCK_FUNCTION (cur_block
) != NULL
)
325 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
329 gdb_assert (find_inline_frame_state (ptid
) == NULL
);
330 inline_states
.emplace_back (ptid
, skip_count
, this_pc
, last_sym
);
333 reinit_frame_cache ();
336 /* Step into an inlined function by unhiding it. */
339 step_into_inline_frame (ptid_t ptid
)
341 struct inline_state
*state
= find_inline_frame_state (ptid
);
343 gdb_assert (state
!= NULL
&& state
->skipped_frames
> 0);
344 state
->skipped_frames
--;
345 reinit_frame_cache ();
348 /* Return the number of hidden functions inlined into the current
352 inline_skipped_frames (ptid_t ptid
)
354 struct inline_state
*state
= find_inline_frame_state (ptid
);
359 return state
->skipped_frames
;
362 /* If one or more inlined functions are hidden, return the symbol for
363 the function inlined into the current frame. */
366 inline_skipped_symbol (ptid_t ptid
)
368 struct inline_state
*state
= find_inline_frame_state (ptid
);
370 gdb_assert (state
!= NULL
);
371 return state
->skipped_symbol
;
374 /* Return the number of functions inlined into THIS_FRAME. Some of
375 the callees may not have associated frames (see
376 skip_inline_frames). */
379 frame_inlined_callees (struct frame_info
*this_frame
)
381 struct frame_info
*next_frame
;
382 int inline_count
= 0;
384 /* First count how many inlined functions at this PC have frames
385 above FRAME (are inlined into FRAME). */
386 for (next_frame
= get_next_frame (this_frame
);
387 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
388 next_frame
= get_next_frame (next_frame
))
391 /* Simulate some most-inner inlined frames which were suppressed, so
392 they can be stepped into later. If we are unwinding already
393 outer frames from some non-inlined frame this does not apply. */
394 if (next_frame
== NULL
)
395 inline_count
+= inline_skipped_frames (inferior_ptid
);