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