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edb3359d DJ |
1 | /* Inline frame unwinder for GDB. |
2 | ||
e2882c85 | 3 | Copyright (C) 2008-2018 Free Software Foundation, Inc. |
edb3359d DJ |
4 | |
5 | This file is part of GDB. | |
6 | ||
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. | |
11 | ||
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. | |
16 | ||
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/>. */ | |
19 | ||
20 | #include "defs.h" | |
e451c4a1 | 21 | #include "inline-frame.h" |
edb3359d DJ |
22 | #include "addrmap.h" |
23 | #include "block.h" | |
24 | #include "frame-unwind.h" | |
25 | #include "inferior.h" | |
4e485129 | 26 | #include "regcache.h" |
edb3359d DJ |
27 | #include "symtab.h" |
28 | #include "vec.h" | |
51d48146 | 29 | #include "frame.h" |
b24531ed | 30 | #include <algorithm> |
edb3359d | 31 | |
edb3359d DJ |
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, | |
35 | keep our own list. */ | |
36 | struct inline_state | |
37 | { | |
b24531ed SM |
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_) | |
42 | {} | |
43 | ||
edb3359d DJ |
44 | /* The thread this data relates to. It should be a currently |
45 | stopped thread; we assume thread IDs never change while the | |
46 | thread is stopped. */ | |
47 | ptid_t ptid; | |
48 | ||
49 | /* The number of inlined functions we are skipping. Each of these | |
50 | functions can be stepped in to. */ | |
51 | int skipped_frames; | |
52 | ||
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. */ | |
57 | CORE_ADDR saved_pc; | |
58 | ||
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; | |
63 | }; | |
64 | ||
b24531ed | 65 | static std::vector<inline_state> inline_states; |
edb3359d | 66 | |
4e485129 DJ |
67 | /* Locate saved inlined frame state for PTID, if it exists |
68 | and is valid. */ | |
edb3359d DJ |
69 | |
70 | static struct inline_state * | |
71 | find_inline_frame_state (ptid_t ptid) | |
72 | { | |
b24531ed SM |
73 | auto state_it = std::find_if (inline_states.begin (), inline_states.end (), |
74 | [&ptid] (const inline_state &state) | |
75 | { | |
76 | return ptid == state.ptid; | |
77 | }); | |
edb3359d | 78 | |
b24531ed SM |
79 | if (state_it == inline_states.end ()) |
80 | return nullptr; | |
edb3359d | 81 | |
b24531ed SM |
82 | inline_state &state = *state_it; |
83 | struct regcache *regcache = get_thread_regcache (ptid); | |
84 | CORE_ADDR current_pc = regcache_read_pc (regcache); | |
edb3359d | 85 | |
b24531ed SM |
86 | if (current_pc != state.saved_pc) |
87 | { | |
88 | /* PC has changed - this context is invalid. Use the | |
89 | default behavior. */ | |
edb3359d | 90 | |
b24531ed SM |
91 | unordered_remove (inline_states, state_it); |
92 | return nullptr; | |
93 | } | |
edb3359d | 94 | |
b24531ed | 95 | return &state; |
edb3359d DJ |
96 | } |
97 | ||
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). */ | |
101 | ||
102 | void | |
103 | clear_inline_frame_state (ptid_t ptid) | |
104 | { | |
b24531ed | 105 | if (ptid == minus_one_ptid) |
edb3359d | 106 | { |
b24531ed | 107 | inline_states.clear (); |
edb3359d DJ |
108 | return; |
109 | } | |
110 | ||
b24531ed | 111 | if (ptid.is_pid ()) |
edb3359d | 112 | { |
b24531ed SM |
113 | int pid = ptid.pid (); |
114 | auto it = std::remove_if (inline_states.begin (), inline_states.end (), | |
115 | [pid] (const inline_state &state) | |
116 | { | |
117 | return pid == state.ptid.pid (); | |
118 | }); | |
119 | ||
120 | inline_states.erase (it, inline_states.end ()); | |
121 | ||
edb3359d DJ |
122 | return; |
123 | } | |
124 | ||
b24531ed SM |
125 | auto it = std::find_if (inline_states.begin (), inline_states.end (), |
126 | [&ptid] (const inline_state &state) | |
127 | { | |
128 | return ptid == state.ptid; | |
129 | }); | |
130 | ||
131 | if (it != inline_states.end ()) | |
132 | unordered_remove (inline_states, it); | |
edb3359d DJ |
133 | } |
134 | ||
135 | static void | |
136 | inline_frame_this_id (struct frame_info *this_frame, | |
137 | void **this_cache, | |
138 | struct frame_id *this_id) | |
139 | { | |
140 | struct symbol *func; | |
141 | ||
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 | |
51d48146 PA |
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)); | |
edb3359d DJ |
149 | |
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)); | |
156 | ||
005ca36a JB |
157 | /* For now, require we don't match outer_frame_id either (see |
158 | comment above). */ | |
159 | gdb_assert (!frame_id_eq (*this_id, outer_frame_id)); | |
160 | ||
edb3359d DJ |
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)); | |
193facb3 | 168 | (*this_id).artificial_depth++; |
edb3359d DJ |
169 | } |
170 | ||
171 | static struct value * | |
172 | inline_frame_prev_register (struct frame_info *this_frame, void **this_cache, | |
173 | int regnum) | |
174 | { | |
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. | |
181 | ||
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); | |
187 | } | |
188 | ||
189 | /* Check whether we are at an inlining site that does not already | |
190 | have an associated frame. */ | |
191 | ||
192 | static int | |
193 | inline_frame_sniffer (const struct frame_unwind *self, | |
194 | struct frame_info *this_frame, | |
195 | void **this_cache) | |
196 | { | |
197 | CORE_ADDR this_pc; | |
3977b71f | 198 | const struct block *frame_block, *cur_block; |
edb3359d DJ |
199 | int depth; |
200 | struct frame_info *next_frame; | |
201 | struct inline_state *state = find_inline_frame_state (inferior_ptid); | |
202 | ||
203 | this_pc = get_frame_address_in_block (this_frame); | |
204 | frame_block = block_for_pc (this_pc); | |
205 | if (frame_block == NULL) | |
206 | return 0; | |
207 | ||
208 | /* Calculate DEPTH, the number of inlined functions at this | |
209 | location. */ | |
210 | depth = 0; | |
211 | cur_block = frame_block; | |
212 | while (BLOCK_SUPERBLOCK (cur_block)) | |
213 | { | |
214 | if (block_inlined_p (cur_block)) | |
215 | depth++; | |
0fa7fe50 JB |
216 | else if (BLOCK_FUNCTION (cur_block) != NULL) |
217 | break; | |
edb3359d DJ |
218 | |
219 | cur_block = BLOCK_SUPERBLOCK (cur_block); | |
220 | } | |
221 | ||
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)) | |
226 | { | |
227 | gdb_assert (depth > 0); | |
228 | depth--; | |
229 | } | |
230 | ||
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) | |
235 | { | |
4e485129 DJ |
236 | gdb_assert (depth >= state->skipped_frames); |
237 | depth -= state->skipped_frames; | |
edb3359d DJ |
238 | } |
239 | ||
240 | /* If all the inlined functions here already have frames, then pass | |
241 | to the normal unwinder for this PC. */ | |
242 | if (depth == 0) | |
243 | return 0; | |
244 | ||
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. */ | |
248 | return 1; | |
249 | } | |
250 | ||
39d7b0e2 | 251 | const struct frame_unwind inline_frame_unwind = { |
edb3359d | 252 | INLINE_FRAME, |
8fbca658 | 253 | default_frame_unwind_stop_reason, |
edb3359d DJ |
254 | inline_frame_this_id, |
255 | inline_frame_prev_register, | |
256 | NULL, | |
257 | inline_frame_sniffer | |
258 | }; | |
259 | ||
edb3359d DJ |
260 | /* Return non-zero if BLOCK, an inlined function block containing PC, |
261 | has a group of contiguous instructions starting at PC (but not | |
262 | before it). */ | |
263 | ||
264 | static int | |
3977b71f | 265 | block_starting_point_at (CORE_ADDR pc, const struct block *block) |
edb3359d | 266 | { |
346d1dfe | 267 | const struct blockvector *bv; |
edb3359d DJ |
268 | struct block *new_block; |
269 | ||
270 | bv = blockvector_for_pc (pc, NULL); | |
271 | if (BLOCKVECTOR_MAP (bv) == NULL) | |
272 | return 0; | |
273 | ||
9a3c8263 | 274 | new_block = (struct block *) addrmap_find (BLOCKVECTOR_MAP (bv), pc - 1); |
edb3359d DJ |
275 | if (new_block == NULL) |
276 | return 1; | |
277 | ||
278 | if (new_block == block || contained_in (new_block, block)) | |
279 | return 0; | |
280 | ||
177b42fe | 281 | /* The immediately preceding address belongs to a different block, |
edb3359d DJ |
282 | which is not a child of this one. Treat this as an entrance into |
283 | BLOCK. */ | |
284 | return 1; | |
285 | } | |
286 | ||
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. */ | |
290 | ||
291 | void | |
292 | skip_inline_frames (ptid_t ptid) | |
293 | { | |
3977b71f | 294 | const struct block *frame_block, *cur_block; |
edb3359d DJ |
295 | struct symbol *last_sym = NULL; |
296 | int skip_count = 0; | |
edb3359d DJ |
297 | |
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. */ | |
b24531ed | 301 | CORE_ADDR this_pc = get_frame_pc (get_current_frame ()); |
edb3359d DJ |
302 | frame_block = block_for_pc (this_pc); |
303 | ||
304 | if (frame_block != NULL) | |
305 | { | |
306 | cur_block = frame_block; | |
307 | while (BLOCK_SUPERBLOCK (cur_block)) | |
308 | { | |
309 | if (block_inlined_p (cur_block)) | |
310 | { | |
311 | /* See comments in inline_frame_this_id about this use | |
312 | of BLOCK_START. */ | |
313 | if (BLOCK_START (cur_block) == this_pc | |
314 | || block_starting_point_at (this_pc, cur_block)) | |
315 | { | |
316 | skip_count++; | |
317 | last_sym = BLOCK_FUNCTION (cur_block); | |
318 | } | |
319 | else | |
320 | break; | |
321 | } | |
0fa7fe50 JB |
322 | else if (BLOCK_FUNCTION (cur_block) != NULL) |
323 | break; | |
324 | ||
edb3359d DJ |
325 | cur_block = BLOCK_SUPERBLOCK (cur_block); |
326 | } | |
327 | } | |
328 | ||
329 | gdb_assert (find_inline_frame_state (ptid) == NULL); | |
b24531ed | 330 | inline_states.emplace_back (ptid, skip_count, this_pc, last_sym); |
edb3359d DJ |
331 | |
332 | if (skip_count != 0) | |
333 | reinit_frame_cache (); | |
334 | } | |
335 | ||
336 | /* Step into an inlined function by unhiding it. */ | |
337 | ||
338 | void | |
339 | step_into_inline_frame (ptid_t ptid) | |
340 | { | |
341 | struct inline_state *state = find_inline_frame_state (ptid); | |
342 | ||
343 | gdb_assert (state != NULL && state->skipped_frames > 0); | |
344 | state->skipped_frames--; | |
345 | reinit_frame_cache (); | |
346 | } | |
347 | ||
348 | /* Return the number of hidden functions inlined into the current | |
349 | frame. */ | |
350 | ||
351 | int | |
352 | inline_skipped_frames (ptid_t ptid) | |
353 | { | |
354 | struct inline_state *state = find_inline_frame_state (ptid); | |
355 | ||
356 | if (state == NULL) | |
357 | return 0; | |
358 | else | |
359 | return state->skipped_frames; | |
360 | } | |
361 | ||
362 | /* If one or more inlined functions are hidden, return the symbol for | |
363 | the function inlined into the current frame. */ | |
364 | ||
365 | struct symbol * | |
366 | inline_skipped_symbol (ptid_t ptid) | |
367 | { | |
368 | struct inline_state *state = find_inline_frame_state (ptid); | |
369 | ||
370 | gdb_assert (state != NULL); | |
371 | return state->skipped_symbol; | |
372 | } | |
373 | ||
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). */ | |
377 | ||
378 | int | |
379 | frame_inlined_callees (struct frame_info *this_frame) | |
380 | { | |
381 | struct frame_info *next_frame; | |
382 | int inline_count = 0; | |
383 | ||
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)) | |
389 | inline_count++; | |
390 | ||
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); | |
396 | ||
397 | return inline_count; | |
398 | } |