Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
42a4f53d | 3 | Copyright (C) 1986-2019 Free Software Foundation, Inc. |
9c1412c1 AC |
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 | |
a9762ec7 | 9 | the Free Software Foundation; either version 3 of the License, or |
9c1412c1 AC |
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 | |
a9762ec7 | 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
9c1412c1 AC |
19 | |
20 | ||
21 | #include "defs.h" | |
22 | #include "dummy-frame.h" | |
4de283e4 | 23 | #include "regcache.h" |
d55e5aa6 | 24 | #include "frame.h" |
4de283e4 TT |
25 | #include "inferior.h" |
26 | #include "frame-unwind.h" | |
27 | #include "command.h" | |
00905d52 | 28 | #include "gdbcmd.h" |
4de283e4 | 29 | #include "observable.h" |
e2e4d78b | 30 | #include "gdbthread.h" |
5e970501 | 31 | #include "infcall.h" |
0d12e84c | 32 | #include "gdbarch.h" |
9c1412c1 | 33 | |
b67a2c6f YQ |
34 | struct dummy_frame_id |
35 | { | |
36 | /* This frame's ID. Must match the value returned by | |
37 | gdbarch_dummy_id. */ | |
38 | struct frame_id id; | |
39 | ||
40 | /* The thread this dummy_frame relates to. */ | |
00431a78 | 41 | thread_info *thread; |
b67a2c6f YQ |
42 | }; |
43 | ||
44 | /* Return whether dummy_frame_id *ID1 and *ID2 are equal. */ | |
45 | ||
46 | static int | |
47 | dummy_frame_id_eq (struct dummy_frame_id *id1, | |
48 | struct dummy_frame_id *id2) | |
49 | { | |
00431a78 | 50 | return frame_id_eq (id1->id, id2->id) && id1->thread == id2->thread; |
b67a2c6f YQ |
51 | } |
52 | ||
10989690 JK |
53 | /* List of dummy_frame destructors. */ |
54 | ||
55 | struct dummy_frame_dtor_list | |
56 | { | |
57 | /* Next element in the list or NULL if this is the last element. */ | |
58 | struct dummy_frame_dtor_list *next; | |
59 | ||
60 | /* If non-NULL, a destructor that is run when this dummy frame is freed. */ | |
61 | dummy_frame_dtor_ftype *dtor; | |
62 | ||
63 | /* Arbitrary data that is passed to DTOR. */ | |
64 | void *dtor_data; | |
65 | }; | |
66 | ||
9c1412c1 AC |
67 | /* Dummy frame. This saves the processor state just prior to setting |
68 | up the inferior function call. Older targets save the registers | |
69 | on the target stack (but that really slows down function calls). */ | |
70 | ||
71 | struct dummy_frame | |
72 | { | |
73 | struct dummy_frame *next; | |
b67a2c6f YQ |
74 | |
75 | /* An id represents a dummy frame. */ | |
76 | struct dummy_frame_id id; | |
77 | ||
b89667eb | 78 | /* The caller's state prior to the call. */ |
16c381f0 | 79 | struct infcall_suspend_state *caller_state; |
233a8fb3 | 80 | |
10989690 JK |
81 | /* First element of destructors list or NULL if there are no |
82 | destructors registered for this dummy_frame. */ | |
83 | struct dummy_frame_dtor_list *dtor_list; | |
9c1412c1 AC |
84 | }; |
85 | ||
86 | static struct dummy_frame *dummy_frame_stack = NULL; | |
87 | ||
b89667eb | 88 | /* Push the caller's state, along with the dummy frame info, onto the |
96860204 | 89 | dummy-frame stack. */ |
9c1412c1 AC |
90 | |
91 | void | |
16c381f0 | 92 | dummy_frame_push (struct infcall_suspend_state *caller_state, |
00431a78 | 93 | const frame_id *dummy_id, thread_info *thread) |
9c1412c1 AC |
94 | { |
95 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 96 | |
41bf6aca | 97 | dummy_frame = XCNEW (struct dummy_frame); |
b89667eb | 98 | dummy_frame->caller_state = caller_state; |
b67a2c6f | 99 | dummy_frame->id.id = (*dummy_id); |
00431a78 | 100 | dummy_frame->id.thread = thread; |
9c1412c1 AC |
101 | dummy_frame->next = dummy_frame_stack; |
102 | dummy_frame_stack = dummy_frame; | |
103 | } | |
104 | ||
b89667eb | 105 | /* Remove *DUMMY_PTR from the dummy frame stack. */ |
a45ae3ed | 106 | |
b89667eb DE |
107 | static void |
108 | remove_dummy_frame (struct dummy_frame **dummy_ptr) | |
a45ae3ed | 109 | { |
b89667eb | 110 | struct dummy_frame *dummy = *dummy_ptr; |
a45ae3ed | 111 | |
10989690 JK |
112 | while (dummy->dtor_list != NULL) |
113 | { | |
114 | struct dummy_frame_dtor_list *list = dummy->dtor_list; | |
115 | ||
116 | dummy->dtor_list = list->next; | |
117 | list->dtor (list->dtor_data, 0); | |
118 | xfree (list); | |
119 | } | |
5e970501 | 120 | |
b89667eb | 121 | *dummy_ptr = dummy->next; |
16c381f0 | 122 | discard_infcall_suspend_state (dummy->caller_state); |
b89667eb | 123 | xfree (dummy); |
a45ae3ed UW |
124 | } |
125 | ||
e2e4d78b JK |
126 | /* Delete any breakpoint B which is a momentary breakpoint for return from |
127 | inferior call matching DUMMY_VOIDP. */ | |
128 | ||
129 | static int | |
130 | pop_dummy_frame_bpt (struct breakpoint *b, void *dummy_voidp) | |
131 | { | |
9a3c8263 | 132 | struct dummy_frame *dummy = (struct dummy_frame *) dummy_voidp; |
e2e4d78b | 133 | |
00431a78 | 134 | if (b->thread == dummy->id.thread->global_num |
b67a2c6f | 135 | && b->disposition == disp_del && frame_id_eq (b->frame_id, dummy->id.id)) |
e2e4d78b JK |
136 | { |
137 | while (b->related_breakpoint != b) | |
138 | delete_breakpoint (b->related_breakpoint); | |
139 | ||
140 | delete_breakpoint (b); | |
141 | ||
142 | /* Stop the traversal. */ | |
143 | return 1; | |
144 | } | |
145 | ||
146 | /* Continue the traversal. */ | |
147 | return 0; | |
148 | } | |
149 | ||
b89667eb DE |
150 | /* Pop *DUMMY_PTR, restoring program state to that before the |
151 | frame was created. */ | |
a45ae3ed UW |
152 | |
153 | static void | |
b89667eb | 154 | pop_dummy_frame (struct dummy_frame **dummy_ptr) |
a45ae3ed | 155 | { |
e2e4d78b JK |
156 | struct dummy_frame *dummy = *dummy_ptr; |
157 | ||
00431a78 | 158 | gdb_assert (dummy->id.thread == inferior_thread ()); |
233a8fb3 | 159 | |
10989690 JK |
160 | while (dummy->dtor_list != NULL) |
161 | { | |
162 | struct dummy_frame_dtor_list *list = dummy->dtor_list; | |
163 | ||
164 | dummy->dtor_list = list->next; | |
165 | list->dtor (list->dtor_data, 1); | |
166 | xfree (list); | |
167 | } | |
233a8fb3 | 168 | |
e2e4d78b | 169 | restore_infcall_suspend_state (dummy->caller_state); |
a45ae3ed | 170 | |
e2e4d78b | 171 | iterate_over_breakpoints (pop_dummy_frame_bpt, dummy); |
b89667eb | 172 | |
16c381f0 | 173 | /* restore_infcall_control_state frees inf_state, |
0963b4bd | 174 | all that remains is to pop *dummy_ptr. */ |
b89667eb DE |
175 | *dummy_ptr = dummy->next; |
176 | xfree (dummy); | |
177 | ||
178 | /* We've made right mess of GDB's local state, just discard | |
179 | everything. */ | |
180 | reinit_frame_cache (); | |
181 | } | |
182 | ||
183 | /* Look up DUMMY_ID. | |
184 | Return NULL if not found. */ | |
185 | ||
186 | static struct dummy_frame ** | |
b67a2c6f | 187 | lookup_dummy_frame (struct dummy_frame_id *dummy_id) |
b89667eb DE |
188 | { |
189 | struct dummy_frame **dp; | |
190 | ||
191 | for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next) | |
a45ae3ed | 192 | { |
b67a2c6f | 193 | if (dummy_frame_id_eq (&(*dp)->id, dummy_id)) |
b89667eb | 194 | return dp; |
a45ae3ed UW |
195 | } |
196 | ||
b89667eb DE |
197 | return NULL; |
198 | } | |
199 | ||
00431a78 | 200 | /* Find the dummy frame by DUMMY_ID and THREAD, and pop it, restoring |
b67a2c6f | 201 | program state to that before the frame was created. |
b89667eb | 202 | On return reinit_frame_cache has been called. |
b67a2c6f | 203 | If the frame isn't found, flag an internal error. */ |
b89667eb DE |
204 | |
205 | void | |
00431a78 | 206 | dummy_frame_pop (frame_id dummy_id, thread_info *thread) |
b89667eb DE |
207 | { |
208 | struct dummy_frame **dp; | |
00431a78 | 209 | struct dummy_frame_id id = { dummy_id, thread }; |
b89667eb | 210 | |
b67a2c6f | 211 | dp = lookup_dummy_frame (&id); |
b89667eb DE |
212 | gdb_assert (dp != NULL); |
213 | ||
214 | pop_dummy_frame (dp); | |
215 | } | |
216 | ||
b67a2c6f YQ |
217 | /* Find the dummy frame by DUMMY_ID and PTID and drop it. Do nothing |
218 | if it is not found. Do not restore its state into inferior, just | |
219 | free its memory. */ | |
e2e4d78b JK |
220 | |
221 | void | |
00431a78 | 222 | dummy_frame_discard (struct frame_id dummy_id, thread_info *thread) |
e2e4d78b JK |
223 | { |
224 | struct dummy_frame **dp; | |
00431a78 | 225 | struct dummy_frame_id id = { dummy_id, thread }; |
e2e4d78b | 226 | |
b67a2c6f | 227 | dp = lookup_dummy_frame (&id); |
e2e4d78b JK |
228 | if (dp) |
229 | remove_dummy_frame (dp); | |
230 | } | |
231 | ||
233a8fb3 JK |
232 | /* See dummy-frame.h. */ |
233 | ||
234 | void | |
00431a78 | 235 | register_dummy_frame_dtor (frame_id dummy_id, thread_info *thread, |
233a8fb3 JK |
236 | dummy_frame_dtor_ftype *dtor, void *dtor_data) |
237 | { | |
00431a78 | 238 | struct dummy_frame_id id = { dummy_id, thread }; |
233a8fb3 | 239 | struct dummy_frame **dp, *d; |
10989690 | 240 | struct dummy_frame_dtor_list *list; |
233a8fb3 JK |
241 | |
242 | dp = lookup_dummy_frame (&id); | |
243 | gdb_assert (dp != NULL); | |
244 | d = *dp; | |
8d749320 | 245 | list = XNEW (struct dummy_frame_dtor_list); |
10989690 JK |
246 | list->next = d->dtor_list; |
247 | d->dtor_list = list; | |
248 | list->dtor = dtor; | |
249 | list->dtor_data = dtor_data; | |
233a8fb3 JK |
250 | } |
251 | ||
252 | /* See dummy-frame.h. */ | |
253 | ||
254 | int | |
255 | find_dummy_frame_dtor (dummy_frame_dtor_ftype *dtor, void *dtor_data) | |
256 | { | |
257 | struct dummy_frame *d; | |
258 | ||
259 | for (d = dummy_frame_stack; d != NULL; d = d->next) | |
10989690 JK |
260 | { |
261 | struct dummy_frame_dtor_list *list; | |
262 | ||
263 | for (list = d->dtor_list; list != NULL; list = list->next) | |
264 | if (list->dtor == dtor && list->dtor_data == dtor_data) | |
265 | return 1; | |
266 | } | |
233a8fb3 JK |
267 | return 0; |
268 | } | |
269 | ||
e2e4d78b JK |
270 | /* There may be stale dummy frames, perhaps left over from when an uncaught |
271 | longjmp took us out of a function that was called by the debugger. Clean | |
272 | them up at least once whenever we start a new inferior. */ | |
b89667eb DE |
273 | |
274 | static void | |
275 | cleanup_dummy_frames (struct target_ops *target, int from_tty) | |
276 | { | |
277 | while (dummy_frame_stack != NULL) | |
278 | remove_dummy_frame (&dummy_frame_stack); | |
a45ae3ed UW |
279 | } |
280 | ||
d67ec5db AC |
281 | /* Return the dummy frame cache, it contains both the ID, and a |
282 | pointer to the regcache. */ | |
283 | struct dummy_frame_cache | |
284 | { | |
285 | struct frame_id this_id; | |
daf6667d | 286 | readonly_detached_regcache *prev_regcache; |
d67ec5db AC |
287 | }; |
288 | ||
b89667eb | 289 | static int |
d67ec5db | 290 | dummy_frame_sniffer (const struct frame_unwind *self, |
669fac23 | 291 | struct frame_info *this_frame, |
d67ec5db AC |
292 | void **this_prologue_cache) |
293 | { | |
d67ec5db AC |
294 | /* When unwinding a normal frame, the stack structure is determined |
295 | by analyzing the frame's function's code (be it using brute force | |
296 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
297 | frame, that simply isn't possible. The PC is either the program | |
298 | entry point, or some random address on the stack. Trying to use | |
299 | that PC to apply standard frame ID unwind techniques is just | |
300 | asking for trouble. */ | |
0c98cc2b | 301 | |
b89667eb | 302 | /* Don't bother unless there is at least one dummy frame. */ |
0c98cc2b | 303 | if (dummy_frame_stack != NULL) |
d67ec5db | 304 | { |
efc889c1 | 305 | struct dummy_frame *dummyframe; |
669fac23 DJ |
306 | /* Use an architecture specific method to extract this frame's |
307 | dummy ID, assuming it is a dummy frame. */ | |
efc889c1 YQ |
308 | struct frame_id this_id |
309 | = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); | |
00431a78 | 310 | struct dummy_frame_id dummy_id = { this_id, inferior_thread () }; |
0c98cc2b MS |
311 | |
312 | /* Use that ID to find the corresponding cache entry. */ | |
313 | for (dummyframe = dummy_frame_stack; | |
314 | dummyframe != NULL; | |
315 | dummyframe = dummyframe->next) | |
3c109c8b | 316 | { |
b67a2c6f | 317 | if (dummy_frame_id_eq (&dummyframe->id, &dummy_id)) |
0c98cc2b MS |
318 | { |
319 | struct dummy_frame_cache *cache; | |
9a619af0 | 320 | |
0c98cc2b | 321 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); |
16c381f0 JK |
322 | cache->prev_regcache = get_infcall_suspend_state_regcache |
323 | (dummyframe->caller_state); | |
0c98cc2b MS |
324 | cache->this_id = this_id; |
325 | (*this_prologue_cache) = cache; | |
326 | return 1; | |
327 | } | |
3c109c8b | 328 | } |
d67ec5db AC |
329 | } |
330 | return 0; | |
331 | } | |
332 | ||
9c1412c1 AC |
333 | /* Given a call-dummy dummy-frame, return the registers. Here the |
334 | register value is taken from the local copy of the register buffer. */ | |
335 | ||
669fac23 DJ |
336 | static struct value * |
337 | dummy_frame_prev_register (struct frame_info *this_frame, | |
6dc42492 | 338 | void **this_prologue_cache, |
669fac23 | 339 | int regnum) |
9c1412c1 | 340 | { |
9a3c8263 SM |
341 | struct dummy_frame_cache *cache |
342 | = (struct dummy_frame_cache *) *this_prologue_cache; | |
669fac23 DJ |
343 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
344 | struct value *reg_val; | |
345 | ||
346 | /* The dummy-frame sniffer always fills in the cache. */ | |
d67ec5db | 347 | gdb_assert (cache != NULL); |
9c1412c1 AC |
348 | |
349 | /* Describe the register's location. Generic dummy frames always | |
350 | have the register value in an ``expression''. */ | |
669fac23 DJ |
351 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
352 | ||
353 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
354 | constructs either a raw or pseudo register from the raw | |
355 | register cache. */ | |
daf6667d YQ |
356 | cache->prev_regcache->cooked_read (regnum, |
357 | value_contents_writeable (reg_val)); | |
669fac23 | 358 | return reg_val; |
9c1412c1 AC |
359 | } |
360 | ||
b89667eb | 361 | /* Assuming that THIS_FRAME is a dummy, return its ID. That ID is |
6dc42492 | 362 | determined by examining the NEXT frame's unwound registers using |
669fac23 | 363 | the method dummy_id(). As a side effect, THIS dummy frame's |
7a9dd1b2 | 364 | dummy cache is located and saved in THIS_PROLOGUE_CACHE. */ |
494cca16 AC |
365 | |
366 | static void | |
669fac23 | 367 | dummy_frame_this_id (struct frame_info *this_frame, |
6dc42492 AC |
368 | void **this_prologue_cache, |
369 | struct frame_id *this_id) | |
c689142b | 370 | { |
d67ec5db | 371 | /* The dummy-frame sniffer always fills in the cache. */ |
9a3c8263 SM |
372 | struct dummy_frame_cache *cache |
373 | = (struct dummy_frame_cache *) *this_prologue_cache; | |
9a619af0 | 374 | |
d67ec5db AC |
375 | gdb_assert (cache != NULL); |
376 | (*this_id) = cache->this_id; | |
c689142b AC |
377 | } |
378 | ||
39d7b0e2 | 379 | const struct frame_unwind dummy_frame_unwind = |
494cca16 | 380 | { |
7df05f2b | 381 | DUMMY_FRAME, |
8fbca658 | 382 | default_frame_unwind_stop_reason, |
6dc42492 | 383 | dummy_frame_this_id, |
d67ec5db AC |
384 | dummy_frame_prev_register, |
385 | NULL, | |
386 | dummy_frame_sniffer, | |
494cca16 AC |
387 | }; |
388 | ||
8bcb5208 AB |
389 | /* See dummy-frame.h. */ |
390 | ||
391 | struct frame_id | |
392 | default_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame) | |
393 | { | |
394 | CORE_ADDR sp, pc; | |
395 | ||
396 | sp = get_frame_sp (this_frame); | |
397 | pc = get_frame_pc (this_frame); | |
398 | return frame_id_build (sp, pc); | |
399 | } | |
400 | ||
00905d52 AC |
401 | static void |
402 | fprint_dummy_frames (struct ui_file *file) | |
403 | { | |
404 | struct dummy_frame *s; | |
9a619af0 | 405 | |
00905d52 AC |
406 | for (s = dummy_frame_stack; s != NULL; s = s->next) |
407 | { | |
408 | gdb_print_host_address (s, file); | |
409 | fprintf_unfiltered (file, ":"); | |
00905d52 | 410 | fprintf_unfiltered (file, " id="); |
b67a2c6f YQ |
411 | fprint_frame_id (file, s->id.id); |
412 | fprintf_unfiltered (file, ", ptid=%s", | |
a068643d | 413 | target_pid_to_str (s->id.thread->ptid).c_str ()); |
00905d52 AC |
414 | fprintf_unfiltered (file, "\n"); |
415 | } | |
416 | } | |
417 | ||
418 | static void | |
31d56ade | 419 | maintenance_print_dummy_frames (const char *args, int from_tty) |
00905d52 AC |
420 | { |
421 | if (args == NULL) | |
422 | fprint_dummy_frames (gdb_stdout); | |
423 | else | |
424 | { | |
d7e74731 | 425 | stdio_file file; |
9a619af0 | 426 | |
d7e74731 | 427 | if (!file.open (args, "w")) |
e2e0b3e5 | 428 | perror_with_name (_("maintenance print dummy-frames")); |
d7e74731 | 429 | fprint_dummy_frames (&file); |
00905d52 AC |
430 | } |
431 | } | |
432 | ||
00905d52 AC |
433 | void |
434 | _initialize_dummy_frame (void) | |
435 | { | |
436 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 437 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
438 | &maintenanceprintlist); |
439 | ||
76727919 | 440 | gdb::observers::inferior_created.attach (cleanup_dummy_frames); |
00905d52 | 441 | } |