1 /* Inline frame unwinder for GDB.
3 Copyright (C) 2008, 2009, 2010 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/>. */
23 #include "frame-unwind.h"
29 #include "gdb_assert.h"
31 /* We need to save a few variables for every thread stopped at the
32 virtual call site of an inlined function. If there was always a
33 "struct thread_info", we could hang it off that; in the mean time,
37 /* The thread this data relates to. It should be a currently
38 stopped thread; we assume thread IDs never change while the
42 /* The number of inlined functions we are skipping. Each of these
43 functions can be stepped in to. */
46 /* Only valid if SKIPPED_FRAMES is non-zero. This is the PC used
47 when calculating SKIPPED_FRAMES; used to check whether we have
48 moved to a new location by user request. If so, we invalidate
49 any skipped frames. */
52 /* Only valid if SKIPPED_FRAMES is non-zero. This is the symbol
53 of the outermost skipped inline function. It's used to find the
54 call site of the current frame. */
55 struct symbol
*skipped_symbol
;
58 typedef struct inline_state inline_state_s
;
59 DEF_VEC_O(inline_state_s
);
61 static VEC(inline_state_s
) *inline_states
;
63 /* Locate saved inlined frame state for PTID, if it exists
66 static struct inline_state
*
67 find_inline_frame_state (ptid_t ptid
)
69 struct inline_state
*state
;
72 for (ix
= 0; VEC_iterate (inline_state_s
, inline_states
, ix
, state
); ix
++)
74 if (ptid_equal (state
->ptid
, ptid
))
76 struct regcache
*regcache
= get_thread_regcache (ptid
);
77 CORE_ADDR current_pc
= regcache_read_pc (regcache
);
79 if (current_pc
!= state
->saved_pc
)
81 /* PC has changed - this context is invalid. Use the
83 VEC_unordered_remove (inline_state_s
, inline_states
, ix
);
94 /* Allocate saved inlined frame state for PTID. */
96 static struct inline_state
*
97 allocate_inline_frame_state (ptid_t ptid
)
99 struct inline_state
*state
;
101 state
= VEC_safe_push (inline_state_s
, inline_states
, NULL
);
102 memset (state
, 0, sizeof (*state
));
108 /* Forget about any hidden inlined functions in PTID, which is new or
109 about to be resumed. PTID may be minus_one_ptid (all processes)
110 or a PID (all threads in this process). */
113 clear_inline_frame_state (ptid_t ptid
)
115 struct inline_state
*state
;
118 if (ptid_equal (ptid
, minus_one_ptid
))
120 VEC_free (inline_state_s
, inline_states
);
124 if (ptid_is_pid (ptid
))
126 VEC (inline_state_s
) *new_states
= NULL
;
127 int pid
= ptid_get_pid (ptid
);
129 for (ix
= 0; VEC_iterate (inline_state_s
, inline_states
, ix
, state
); ix
++)
130 if (pid
!= ptid_get_pid (state
->ptid
))
131 VEC_safe_push (inline_state_s
, new_states
, state
);
132 VEC_free (inline_state_s
, inline_states
);
133 inline_states
= new_states
;
137 for (ix
= 0; VEC_iterate (inline_state_s
, inline_states
, ix
, state
); ix
++)
138 if (ptid_equal (state
->ptid
, ptid
))
140 VEC_unordered_remove (inline_state_s
, inline_states
, ix
);
146 inline_frame_this_id (struct frame_info
*this_frame
,
148 struct frame_id
*this_id
)
152 /* In order to have a stable frame ID for a given inline function,
153 we must get the stack / special addresses from the underlying
154 real frame's this_id method. So we must call get_prev_frame.
155 Because we are inlined into some function, there must be previous
156 frames, so this is safe - as long as we're careful not to
157 create any cycles. */
158 *this_id
= get_frame_id (get_prev_frame (this_frame
));
160 /* We need a valid frame ID, so we need to be based on a valid
161 frame. FSF submission NOTE: this would be a good assertion to
162 apply to all frames, all the time. That would fix the ambiguity
163 of null_frame_id (between "no/any frame" and "the outermost
164 frame"). This will take work. */
165 gdb_assert (frame_id_p (*this_id
));
167 /* For now, require we don't match outer_frame_id either (see
169 gdb_assert (!frame_id_eq (*this_id
, outer_frame_id
));
171 /* Future work NOTE: Alexandre Oliva applied a patch to GCC 4.3
172 which generates DW_AT_entry_pc for inlined functions when
173 possible. If this attribute is available, we should use it
174 in the frame ID (and eventually, to set breakpoints). */
175 func
= get_frame_function (this_frame
);
176 gdb_assert (func
!= NULL
);
177 (*this_id
).code_addr
= BLOCK_START (SYMBOL_BLOCK_VALUE (func
));
178 (*this_id
).inline_depth
++;
181 static struct value
*
182 inline_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
185 /* Use get_frame_register_value instead of
186 frame_unwind_got_register, to avoid requiring this frame's ID.
187 This frame's ID depends on the previous frame's ID (unusual), and
188 the previous frame's ID depends on this frame's unwound
189 registers. If unwinding registers from this frame called
190 get_frame_id, there would be a loop.
192 Do not copy this code into any other unwinder! Inlined functions
193 are special; other unwinders must not have a dependency on the
194 previous frame's ID, and therefore can and should use
195 frame_unwind_got_register instead. */
196 return get_frame_register_value (this_frame
, regnum
);
199 /* Check whether we are at an inlining site that does not already
200 have an associated frame. */
203 inline_frame_sniffer (const struct frame_unwind
*self
,
204 struct frame_info
*this_frame
,
208 struct block
*frame_block
, *cur_block
;
210 struct frame_info
*next_frame
;
211 struct inline_state
*state
= find_inline_frame_state (inferior_ptid
);
213 this_pc
= get_frame_address_in_block (this_frame
);
214 frame_block
= block_for_pc (this_pc
);
215 if (frame_block
== NULL
)
218 /* Calculate DEPTH, the number of inlined functions at this
221 cur_block
= frame_block
;
222 while (BLOCK_SUPERBLOCK (cur_block
))
224 if (block_inlined_p (cur_block
))
227 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
230 /* Check how many inlined functions already have frames. */
231 for (next_frame
= get_next_frame (this_frame
);
232 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
233 next_frame
= get_next_frame (next_frame
))
235 gdb_assert (depth
> 0);
239 /* If this is the topmost frame, or all frames above us are inlined,
240 then check whether we were requested to skip some frames (so they
241 can be stepped into later). */
242 if (state
!= NULL
&& state
->skipped_frames
> 0 && next_frame
== NULL
)
244 gdb_assert (depth
>= state
->skipped_frames
);
245 depth
-= state
->skipped_frames
;
248 /* If all the inlined functions here already have frames, then pass
249 to the normal unwinder for this PC. */
253 /* If the next frame is an inlined function, but not the outermost, then
254 we are the next outer. If it is not an inlined function, then we
255 are the innermost inlined function of a different real frame. */
259 const struct frame_unwind inline_frame_unwinder
= {
261 inline_frame_this_id
,
262 inline_frame_prev_register
,
267 const struct frame_unwind
*const inline_frame_unwind
= &inline_frame_unwinder
;
269 /* Return non-zero if BLOCK, an inlined function block containing PC,
270 has a group of contiguous instructions starting at PC (but not
274 block_starting_point_at (CORE_ADDR pc
, struct block
*block
)
276 struct blockvector
*bv
;
277 struct block
*new_block
;
279 bv
= blockvector_for_pc (pc
, NULL
);
280 if (BLOCKVECTOR_MAP (bv
) == NULL
)
283 new_block
= addrmap_find (BLOCKVECTOR_MAP (bv
), pc
- 1);
284 if (new_block
== NULL
)
287 if (new_block
== block
|| contained_in (new_block
, block
))
290 /* The immediately preceeding address belongs to a different block,
291 which is not a child of this one. Treat this as an entrance into
296 /* Skip all inlined functions whose call sites are at the current PC.
297 Frames for the hidden functions will not appear in the backtrace until the
298 user steps into them. */
301 skip_inline_frames (ptid_t ptid
)
304 struct block
*frame_block
, *cur_block
;
305 struct symbol
*last_sym
= NULL
;
307 struct inline_state
*state
;
309 /* This function is called right after reinitializing the frame
310 cache. We try not to do more unwinding than absolutely
311 necessary, for performance. */
312 this_pc
= get_frame_pc (get_current_frame ());
313 frame_block
= block_for_pc (this_pc
);
315 if (frame_block
!= NULL
)
317 cur_block
= frame_block
;
318 while (BLOCK_SUPERBLOCK (cur_block
))
320 if (block_inlined_p (cur_block
))
322 /* See comments in inline_frame_this_id about this use
324 if (BLOCK_START (cur_block
) == this_pc
325 || block_starting_point_at (this_pc
, cur_block
))
328 last_sym
= BLOCK_FUNCTION (cur_block
);
333 cur_block
= BLOCK_SUPERBLOCK (cur_block
);
337 gdb_assert (find_inline_frame_state (ptid
) == NULL
);
338 state
= allocate_inline_frame_state (ptid
);
339 state
->skipped_frames
= skip_count
;
340 state
->saved_pc
= this_pc
;
341 state
->skipped_symbol
= last_sym
;
344 reinit_frame_cache ();
347 /* Step into an inlined function by unhiding it. */
350 step_into_inline_frame (ptid_t ptid
)
352 struct inline_state
*state
= find_inline_frame_state (ptid
);
354 gdb_assert (state
!= NULL
&& state
->skipped_frames
> 0);
355 state
->skipped_frames
--;
356 reinit_frame_cache ();
359 /* Return the number of hidden functions inlined into the current
363 inline_skipped_frames (ptid_t ptid
)
365 struct inline_state
*state
= find_inline_frame_state (ptid
);
370 return state
->skipped_frames
;
373 /* If one or more inlined functions are hidden, return the symbol for
374 the function inlined into the current frame. */
377 inline_skipped_symbol (ptid_t ptid
)
379 struct inline_state
*state
= find_inline_frame_state (ptid
);
381 gdb_assert (state
!= NULL
);
382 return state
->skipped_symbol
;
385 /* Return the number of functions inlined into THIS_FRAME. Some of
386 the callees may not have associated frames (see
387 skip_inline_frames). */
390 frame_inlined_callees (struct frame_info
*this_frame
)
392 struct frame_info
*next_frame
;
393 int inline_count
= 0;
395 /* First count how many inlined functions at this PC have frames
396 above FRAME (are inlined into FRAME). */
397 for (next_frame
= get_next_frame (this_frame
);
398 next_frame
&& get_frame_type (next_frame
) == INLINE_FRAME
;
399 next_frame
= get_next_frame (next_frame
))
402 /* Simulate some most-inner inlined frames which were suppressed, so
403 they can be stepped into later. If we are unwinding already
404 outer frames from some non-inlined frame this does not apply. */
405 if (next_frame
== NULL
)
406 inline_count
+= inline_skipped_frames (inferior_ptid
);