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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
32d0add0 | 3 | Copyright (C) 1986-2015 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" | |
23 | #include "regcache.h" | |
24 | #include "frame.h" | |
25 | #include "inferior.h" | |
494cca16 | 26 | #include "frame-unwind.h" |
00905d52 AC |
27 | #include "command.h" |
28 | #include "gdbcmd.h" | |
a45ae3ed | 29 | #include "observer.h" |
e2e4d78b | 30 | #include "gdbthread.h" |
5e970501 | 31 | #include "infcall.h" |
9c1412c1 | 32 | |
b67a2c6f YQ |
33 | struct dummy_frame_id |
34 | { | |
35 | /* This frame's ID. Must match the value returned by | |
36 | gdbarch_dummy_id. */ | |
37 | struct frame_id id; | |
38 | ||
39 | /* The thread this dummy_frame relates to. */ | |
40 | ptid_t ptid; | |
41 | }; | |
42 | ||
43 | /* Return whether dummy_frame_id *ID1 and *ID2 are equal. */ | |
44 | ||
45 | static int | |
46 | dummy_frame_id_eq (struct dummy_frame_id *id1, | |
47 | struct dummy_frame_id *id2) | |
48 | { | |
49 | return frame_id_eq (id1->id, id2->id) && ptid_equal (id1->ptid, id2->ptid); | |
50 | } | |
51 | ||
9c1412c1 AC |
52 | /* Dummy frame. This saves the processor state just prior to setting |
53 | up the inferior function call. Older targets save the registers | |
54 | on the target stack (but that really slows down function calls). */ | |
55 | ||
56 | struct dummy_frame | |
57 | { | |
58 | struct dummy_frame *next; | |
b67a2c6f YQ |
59 | |
60 | /* An id represents a dummy frame. */ | |
61 | struct dummy_frame_id id; | |
62 | ||
b89667eb | 63 | /* The caller's state prior to the call. */ |
16c381f0 | 64 | struct infcall_suspend_state *caller_state; |
233a8fb3 | 65 | |
5e970501 | 66 | /* If non-NULL, a destructor that is run when this dummy frame is freed. */ |
558e5469 | 67 | dummy_frame_dtor_ftype *dtor; |
233a8fb3 JK |
68 | |
69 | /* Arbitrary data that is passed to DTOR. */ | |
70 | void *dtor_data; | |
9c1412c1 AC |
71 | }; |
72 | ||
73 | static struct dummy_frame *dummy_frame_stack = NULL; | |
74 | ||
b89667eb | 75 | /* Push the caller's state, along with the dummy frame info, onto the |
96860204 | 76 | dummy-frame stack. */ |
9c1412c1 AC |
77 | |
78 | void | |
16c381f0 | 79 | dummy_frame_push (struct infcall_suspend_state *caller_state, |
b67a2c6f | 80 | const struct frame_id *dummy_id, ptid_t ptid) |
9c1412c1 AC |
81 | { |
82 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 83 | |
41bf6aca | 84 | dummy_frame = XCNEW (struct dummy_frame); |
b89667eb | 85 | dummy_frame->caller_state = caller_state; |
b67a2c6f YQ |
86 | dummy_frame->id.id = (*dummy_id); |
87 | dummy_frame->id.ptid = ptid; | |
9c1412c1 AC |
88 | dummy_frame->next = dummy_frame_stack; |
89 | dummy_frame_stack = dummy_frame; | |
90 | } | |
91 | ||
b89667eb | 92 | /* Remove *DUMMY_PTR from the dummy frame stack. */ |
a45ae3ed | 93 | |
b89667eb DE |
94 | static void |
95 | remove_dummy_frame (struct dummy_frame **dummy_ptr) | |
a45ae3ed | 96 | { |
b89667eb | 97 | struct dummy_frame *dummy = *dummy_ptr; |
a45ae3ed | 98 | |
5e970501 JK |
99 | if (dummy->dtor != NULL) |
100 | dummy->dtor (dummy->dtor_data, 0); | |
101 | ||
b89667eb | 102 | *dummy_ptr = dummy->next; |
16c381f0 | 103 | discard_infcall_suspend_state (dummy->caller_state); |
b89667eb | 104 | xfree (dummy); |
a45ae3ed UW |
105 | } |
106 | ||
e2e4d78b JK |
107 | /* Delete any breakpoint B which is a momentary breakpoint for return from |
108 | inferior call matching DUMMY_VOIDP. */ | |
109 | ||
110 | static int | |
111 | pop_dummy_frame_bpt (struct breakpoint *b, void *dummy_voidp) | |
112 | { | |
113 | struct dummy_frame *dummy = dummy_voidp; | |
114 | ||
b67a2c6f YQ |
115 | if (b->thread == pid_to_thread_id (dummy->id.ptid) |
116 | && b->disposition == disp_del && frame_id_eq (b->frame_id, dummy->id.id)) | |
e2e4d78b JK |
117 | { |
118 | while (b->related_breakpoint != b) | |
119 | delete_breakpoint (b->related_breakpoint); | |
120 | ||
121 | delete_breakpoint (b); | |
122 | ||
123 | /* Stop the traversal. */ | |
124 | return 1; | |
125 | } | |
126 | ||
127 | /* Continue the traversal. */ | |
128 | return 0; | |
129 | } | |
130 | ||
b89667eb DE |
131 | /* Pop *DUMMY_PTR, restoring program state to that before the |
132 | frame was created. */ | |
a45ae3ed UW |
133 | |
134 | static void | |
b89667eb | 135 | pop_dummy_frame (struct dummy_frame **dummy_ptr) |
a45ae3ed | 136 | { |
e2e4d78b JK |
137 | struct dummy_frame *dummy = *dummy_ptr; |
138 | ||
b67a2c6f | 139 | gdb_assert (ptid_equal (dummy->id.ptid, inferior_ptid)); |
233a8fb3 JK |
140 | |
141 | if (dummy->dtor != NULL) | |
5e970501 | 142 | dummy->dtor (dummy->dtor_data, 1); |
233a8fb3 | 143 | |
e2e4d78b | 144 | restore_infcall_suspend_state (dummy->caller_state); |
a45ae3ed | 145 | |
e2e4d78b | 146 | iterate_over_breakpoints (pop_dummy_frame_bpt, dummy); |
b89667eb | 147 | |
16c381f0 | 148 | /* restore_infcall_control_state frees inf_state, |
0963b4bd | 149 | all that remains is to pop *dummy_ptr. */ |
b89667eb DE |
150 | *dummy_ptr = dummy->next; |
151 | xfree (dummy); | |
152 | ||
153 | /* We've made right mess of GDB's local state, just discard | |
154 | everything. */ | |
155 | reinit_frame_cache (); | |
156 | } | |
157 | ||
158 | /* Look up DUMMY_ID. | |
159 | Return NULL if not found. */ | |
160 | ||
161 | static struct dummy_frame ** | |
b67a2c6f | 162 | lookup_dummy_frame (struct dummy_frame_id *dummy_id) |
b89667eb DE |
163 | { |
164 | struct dummy_frame **dp; | |
165 | ||
166 | for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next) | |
a45ae3ed | 167 | { |
b67a2c6f | 168 | if (dummy_frame_id_eq (&(*dp)->id, dummy_id)) |
b89667eb | 169 | return dp; |
a45ae3ed UW |
170 | } |
171 | ||
b89667eb DE |
172 | return NULL; |
173 | } | |
174 | ||
b67a2c6f YQ |
175 | /* Find the dummy frame by DUMMY_ID and PTID, and pop it, restoring |
176 | program state to that before the frame was created. | |
b89667eb | 177 | On return reinit_frame_cache has been called. |
b67a2c6f | 178 | If the frame isn't found, flag an internal error. */ |
b89667eb DE |
179 | |
180 | void | |
b67a2c6f | 181 | dummy_frame_pop (struct frame_id dummy_id, ptid_t ptid) |
b89667eb DE |
182 | { |
183 | struct dummy_frame **dp; | |
b67a2c6f | 184 | struct dummy_frame_id id = { dummy_id, ptid }; |
b89667eb | 185 | |
b67a2c6f | 186 | dp = lookup_dummy_frame (&id); |
b89667eb DE |
187 | gdb_assert (dp != NULL); |
188 | ||
189 | pop_dummy_frame (dp); | |
190 | } | |
191 | ||
b67a2c6f YQ |
192 | /* Find the dummy frame by DUMMY_ID and PTID and drop it. Do nothing |
193 | if it is not found. Do not restore its state into inferior, just | |
194 | free its memory. */ | |
e2e4d78b JK |
195 | |
196 | void | |
b67a2c6f | 197 | dummy_frame_discard (struct frame_id dummy_id, ptid_t ptid) |
e2e4d78b JK |
198 | { |
199 | struct dummy_frame **dp; | |
b67a2c6f | 200 | struct dummy_frame_id id = { dummy_id, ptid }; |
e2e4d78b | 201 | |
b67a2c6f | 202 | dp = lookup_dummy_frame (&id); |
e2e4d78b JK |
203 | if (dp) |
204 | remove_dummy_frame (dp); | |
205 | } | |
206 | ||
233a8fb3 JK |
207 | /* See dummy-frame.h. */ |
208 | ||
209 | void | |
210 | register_dummy_frame_dtor (struct frame_id dummy_id, ptid_t ptid, | |
211 | dummy_frame_dtor_ftype *dtor, void *dtor_data) | |
212 | { | |
213 | struct dummy_frame_id id = { dummy_id, ptid }; | |
214 | struct dummy_frame **dp, *d; | |
215 | ||
216 | dp = lookup_dummy_frame (&id); | |
217 | gdb_assert (dp != NULL); | |
218 | d = *dp; | |
219 | gdb_assert (d->dtor == NULL); | |
220 | d->dtor = dtor; | |
221 | d->dtor_data = dtor_data; | |
222 | } | |
223 | ||
224 | /* See dummy-frame.h. */ | |
225 | ||
226 | int | |
227 | find_dummy_frame_dtor (dummy_frame_dtor_ftype *dtor, void *dtor_data) | |
228 | { | |
229 | struct dummy_frame *d; | |
230 | ||
231 | for (d = dummy_frame_stack; d != NULL; d = d->next) | |
232 | if (d->dtor == dtor && d->dtor_data == dtor_data) | |
233 | return 1; | |
234 | return 0; | |
235 | } | |
236 | ||
e2e4d78b JK |
237 | /* There may be stale dummy frames, perhaps left over from when an uncaught |
238 | longjmp took us out of a function that was called by the debugger. Clean | |
239 | them up at least once whenever we start a new inferior. */ | |
b89667eb DE |
240 | |
241 | static void | |
242 | cleanup_dummy_frames (struct target_ops *target, int from_tty) | |
243 | { | |
244 | while (dummy_frame_stack != NULL) | |
245 | remove_dummy_frame (&dummy_frame_stack); | |
a45ae3ed UW |
246 | } |
247 | ||
d67ec5db AC |
248 | /* Return the dummy frame cache, it contains both the ID, and a |
249 | pointer to the regcache. */ | |
250 | struct dummy_frame_cache | |
251 | { | |
252 | struct frame_id this_id; | |
253 | struct regcache *prev_regcache; | |
254 | }; | |
255 | ||
b89667eb | 256 | static int |
d67ec5db | 257 | dummy_frame_sniffer (const struct frame_unwind *self, |
669fac23 | 258 | struct frame_info *this_frame, |
d67ec5db AC |
259 | void **this_prologue_cache) |
260 | { | |
d67ec5db AC |
261 | /* When unwinding a normal frame, the stack structure is determined |
262 | by analyzing the frame's function's code (be it using brute force | |
263 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
264 | frame, that simply isn't possible. The PC is either the program | |
265 | entry point, or some random address on the stack. Trying to use | |
266 | that PC to apply standard frame ID unwind techniques is just | |
267 | asking for trouble. */ | |
0c98cc2b | 268 | |
b89667eb | 269 | /* Don't bother unless there is at least one dummy frame. */ |
0c98cc2b | 270 | if (dummy_frame_stack != NULL) |
d67ec5db | 271 | { |
efc889c1 | 272 | struct dummy_frame *dummyframe; |
669fac23 DJ |
273 | /* Use an architecture specific method to extract this frame's |
274 | dummy ID, assuming it is a dummy frame. */ | |
efc889c1 YQ |
275 | struct frame_id this_id |
276 | = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); | |
b67a2c6f | 277 | struct dummy_frame_id dummy_id = { this_id, inferior_ptid }; |
0c98cc2b MS |
278 | |
279 | /* Use that ID to find the corresponding cache entry. */ | |
280 | for (dummyframe = dummy_frame_stack; | |
281 | dummyframe != NULL; | |
282 | dummyframe = dummyframe->next) | |
3c109c8b | 283 | { |
b67a2c6f | 284 | if (dummy_frame_id_eq (&dummyframe->id, &dummy_id)) |
0c98cc2b MS |
285 | { |
286 | struct dummy_frame_cache *cache; | |
9a619af0 | 287 | |
0c98cc2b | 288 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); |
16c381f0 JK |
289 | cache->prev_regcache = get_infcall_suspend_state_regcache |
290 | (dummyframe->caller_state); | |
0c98cc2b MS |
291 | cache->this_id = this_id; |
292 | (*this_prologue_cache) = cache; | |
293 | return 1; | |
294 | } | |
3c109c8b | 295 | } |
d67ec5db AC |
296 | } |
297 | return 0; | |
298 | } | |
299 | ||
9c1412c1 AC |
300 | /* Given a call-dummy dummy-frame, return the registers. Here the |
301 | register value is taken from the local copy of the register buffer. */ | |
302 | ||
669fac23 DJ |
303 | static struct value * |
304 | dummy_frame_prev_register (struct frame_info *this_frame, | |
6dc42492 | 305 | void **this_prologue_cache, |
669fac23 | 306 | int regnum) |
9c1412c1 | 307 | { |
d67ec5db | 308 | struct dummy_frame_cache *cache = (*this_prologue_cache); |
669fac23 DJ |
309 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
310 | struct value *reg_val; | |
311 | ||
312 | /* The dummy-frame sniffer always fills in the cache. */ | |
d67ec5db | 313 | gdb_assert (cache != NULL); |
9c1412c1 AC |
314 | |
315 | /* Describe the register's location. Generic dummy frames always | |
316 | have the register value in an ``expression''. */ | |
669fac23 DJ |
317 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
318 | ||
319 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
320 | constructs either a raw or pseudo register from the raw | |
321 | register cache. */ | |
322 | regcache_cooked_read (cache->prev_regcache, regnum, | |
323 | value_contents_writeable (reg_val)); | |
324 | return reg_val; | |
9c1412c1 AC |
325 | } |
326 | ||
b89667eb | 327 | /* Assuming that THIS_FRAME is a dummy, return its ID. That ID is |
6dc42492 | 328 | determined by examining the NEXT frame's unwound registers using |
669fac23 | 329 | the method dummy_id(). As a side effect, THIS dummy frame's |
7a9dd1b2 | 330 | dummy cache is located and saved in THIS_PROLOGUE_CACHE. */ |
494cca16 AC |
331 | |
332 | static void | |
669fac23 | 333 | dummy_frame_this_id (struct frame_info *this_frame, |
6dc42492 AC |
334 | void **this_prologue_cache, |
335 | struct frame_id *this_id) | |
c689142b | 336 | { |
d67ec5db AC |
337 | /* The dummy-frame sniffer always fills in the cache. */ |
338 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
9a619af0 | 339 | |
d67ec5db AC |
340 | gdb_assert (cache != NULL); |
341 | (*this_id) = cache->this_id; | |
c689142b AC |
342 | } |
343 | ||
39d7b0e2 | 344 | const struct frame_unwind dummy_frame_unwind = |
494cca16 | 345 | { |
7df05f2b | 346 | DUMMY_FRAME, |
8fbca658 | 347 | default_frame_unwind_stop_reason, |
6dc42492 | 348 | dummy_frame_this_id, |
d67ec5db AC |
349 | dummy_frame_prev_register, |
350 | NULL, | |
351 | dummy_frame_sniffer, | |
494cca16 AC |
352 | }; |
353 | ||
00905d52 AC |
354 | static void |
355 | fprint_dummy_frames (struct ui_file *file) | |
356 | { | |
357 | struct dummy_frame *s; | |
9a619af0 | 358 | |
00905d52 AC |
359 | for (s = dummy_frame_stack; s != NULL; s = s->next) |
360 | { | |
361 | gdb_print_host_address (s, file); | |
362 | fprintf_unfiltered (file, ":"); | |
00905d52 | 363 | fprintf_unfiltered (file, " id="); |
b67a2c6f YQ |
364 | fprint_frame_id (file, s->id.id); |
365 | fprintf_unfiltered (file, ", ptid=%s", | |
366 | target_pid_to_str (s->id.ptid)); | |
00905d52 AC |
367 | fprintf_unfiltered (file, "\n"); |
368 | } | |
369 | } | |
370 | ||
371 | static void | |
372 | maintenance_print_dummy_frames (char *args, int from_tty) | |
373 | { | |
374 | if (args == NULL) | |
375 | fprint_dummy_frames (gdb_stdout); | |
376 | else | |
377 | { | |
724b958c | 378 | struct cleanup *cleanups; |
00905d52 | 379 | struct ui_file *file = gdb_fopen (args, "w"); |
9a619af0 | 380 | |
00905d52 | 381 | if (file == NULL) |
e2e0b3e5 | 382 | perror_with_name (_("maintenance print dummy-frames")); |
724b958c | 383 | cleanups = make_cleanup_ui_file_delete (file); |
00905d52 | 384 | fprint_dummy_frames (file); |
724b958c | 385 | do_cleanups (cleanups); |
00905d52 AC |
386 | } |
387 | } | |
388 | ||
389 | extern void _initialize_dummy_frame (void); | |
390 | ||
391 | void | |
392 | _initialize_dummy_frame (void) | |
393 | { | |
394 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 395 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
396 | &maintenanceprintlist); |
397 | ||
a45ae3ed | 398 | observer_attach_inferior_created (cleanup_dummy_frames); |
00905d52 | 399 | } |