Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
ecd75fc8 | 3 | Copyright (C) 1986-2014 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; |
9c1412c1 AC |
64 | }; |
65 | ||
66 | static struct dummy_frame *dummy_frame_stack = NULL; | |
67 | ||
b89667eb | 68 | /* Push the caller's state, along with the dummy frame info, onto the |
96860204 | 69 | dummy-frame stack. */ |
9c1412c1 AC |
70 | |
71 | void | |
16c381f0 | 72 | dummy_frame_push (struct infcall_suspend_state *caller_state, |
b67a2c6f | 73 | const struct frame_id *dummy_id, ptid_t ptid) |
9c1412c1 AC |
74 | { |
75 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 76 | |
41bf6aca | 77 | dummy_frame = XCNEW (struct dummy_frame); |
b89667eb | 78 | dummy_frame->caller_state = caller_state; |
b67a2c6f YQ |
79 | dummy_frame->id.id = (*dummy_id); |
80 | dummy_frame->id.ptid = ptid; | |
9c1412c1 AC |
81 | dummy_frame->next = dummy_frame_stack; |
82 | dummy_frame_stack = dummy_frame; | |
83 | } | |
84 | ||
b89667eb | 85 | /* Remove *DUMMY_PTR from the dummy frame stack. */ |
a45ae3ed | 86 | |
b89667eb DE |
87 | static void |
88 | remove_dummy_frame (struct dummy_frame **dummy_ptr) | |
a45ae3ed | 89 | { |
b89667eb | 90 | struct dummy_frame *dummy = *dummy_ptr; |
a45ae3ed | 91 | |
b89667eb | 92 | *dummy_ptr = dummy->next; |
16c381f0 | 93 | discard_infcall_suspend_state (dummy->caller_state); |
b89667eb | 94 | xfree (dummy); |
a45ae3ed UW |
95 | } |
96 | ||
e2e4d78b JK |
97 | /* Delete any breakpoint B which is a momentary breakpoint for return from |
98 | inferior call matching DUMMY_VOIDP. */ | |
99 | ||
100 | static int | |
101 | pop_dummy_frame_bpt (struct breakpoint *b, void *dummy_voidp) | |
102 | { | |
103 | struct dummy_frame *dummy = dummy_voidp; | |
104 | ||
b67a2c6f YQ |
105 | if (b->thread == pid_to_thread_id (dummy->id.ptid) |
106 | && b->disposition == disp_del && frame_id_eq (b->frame_id, dummy->id.id)) | |
e2e4d78b JK |
107 | { |
108 | while (b->related_breakpoint != b) | |
109 | delete_breakpoint (b->related_breakpoint); | |
110 | ||
111 | delete_breakpoint (b); | |
112 | ||
113 | /* Stop the traversal. */ | |
114 | return 1; | |
115 | } | |
116 | ||
117 | /* Continue the traversal. */ | |
118 | return 0; | |
119 | } | |
120 | ||
b89667eb DE |
121 | /* Pop *DUMMY_PTR, restoring program state to that before the |
122 | frame was created. */ | |
a45ae3ed UW |
123 | |
124 | static void | |
b89667eb | 125 | pop_dummy_frame (struct dummy_frame **dummy_ptr) |
a45ae3ed | 126 | { |
e2e4d78b JK |
127 | struct dummy_frame *dummy = *dummy_ptr; |
128 | ||
b67a2c6f | 129 | gdb_assert (ptid_equal (dummy->id.ptid, inferior_ptid)); |
e2e4d78b | 130 | restore_infcall_suspend_state (dummy->caller_state); |
a45ae3ed | 131 | |
e2e4d78b | 132 | iterate_over_breakpoints (pop_dummy_frame_bpt, dummy); |
b89667eb | 133 | |
16c381f0 | 134 | /* restore_infcall_control_state frees inf_state, |
0963b4bd | 135 | all that remains is to pop *dummy_ptr. */ |
b89667eb DE |
136 | *dummy_ptr = dummy->next; |
137 | xfree (dummy); | |
138 | ||
139 | /* We've made right mess of GDB's local state, just discard | |
140 | everything. */ | |
141 | reinit_frame_cache (); | |
142 | } | |
143 | ||
144 | /* Look up DUMMY_ID. | |
145 | Return NULL if not found. */ | |
146 | ||
147 | static struct dummy_frame ** | |
b67a2c6f | 148 | lookup_dummy_frame (struct dummy_frame_id *dummy_id) |
b89667eb DE |
149 | { |
150 | struct dummy_frame **dp; | |
151 | ||
152 | for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next) | |
a45ae3ed | 153 | { |
b67a2c6f | 154 | if (dummy_frame_id_eq (&(*dp)->id, dummy_id)) |
b89667eb | 155 | return dp; |
a45ae3ed UW |
156 | } |
157 | ||
b89667eb DE |
158 | return NULL; |
159 | } | |
160 | ||
b67a2c6f YQ |
161 | /* Find the dummy frame by DUMMY_ID and PTID, and pop it, restoring |
162 | program state to that before the frame was created. | |
b89667eb | 163 | On return reinit_frame_cache has been called. |
b67a2c6f | 164 | If the frame isn't found, flag an internal error. */ |
b89667eb DE |
165 | |
166 | void | |
b67a2c6f | 167 | dummy_frame_pop (struct frame_id dummy_id, ptid_t ptid) |
b89667eb DE |
168 | { |
169 | struct dummy_frame **dp; | |
b67a2c6f | 170 | struct dummy_frame_id id = { dummy_id, ptid }; |
b89667eb | 171 | |
b67a2c6f | 172 | dp = lookup_dummy_frame (&id); |
b89667eb DE |
173 | gdb_assert (dp != NULL); |
174 | ||
175 | pop_dummy_frame (dp); | |
176 | } | |
177 | ||
b67a2c6f YQ |
178 | /* Find the dummy frame by DUMMY_ID and PTID and drop it. Do nothing |
179 | if it is not found. Do not restore its state into inferior, just | |
180 | free its memory. */ | |
e2e4d78b JK |
181 | |
182 | void | |
b67a2c6f | 183 | dummy_frame_discard (struct frame_id dummy_id, ptid_t ptid) |
e2e4d78b JK |
184 | { |
185 | struct dummy_frame **dp; | |
b67a2c6f | 186 | struct dummy_frame_id id = { dummy_id, ptid }; |
e2e4d78b | 187 | |
b67a2c6f | 188 | dp = lookup_dummy_frame (&id); |
e2e4d78b JK |
189 | if (dp) |
190 | remove_dummy_frame (dp); | |
191 | } | |
192 | ||
193 | /* There may be stale dummy frames, perhaps left over from when an uncaught | |
194 | longjmp took us out of a function that was called by the debugger. Clean | |
195 | them up at least once whenever we start a new inferior. */ | |
b89667eb DE |
196 | |
197 | static void | |
198 | cleanup_dummy_frames (struct target_ops *target, int from_tty) | |
199 | { | |
200 | while (dummy_frame_stack != NULL) | |
201 | remove_dummy_frame (&dummy_frame_stack); | |
a45ae3ed UW |
202 | } |
203 | ||
d67ec5db AC |
204 | /* Return the dummy frame cache, it contains both the ID, and a |
205 | pointer to the regcache. */ | |
206 | struct dummy_frame_cache | |
207 | { | |
208 | struct frame_id this_id; | |
209 | struct regcache *prev_regcache; | |
210 | }; | |
211 | ||
b89667eb | 212 | static int |
d67ec5db | 213 | dummy_frame_sniffer (const struct frame_unwind *self, |
669fac23 | 214 | struct frame_info *this_frame, |
d67ec5db AC |
215 | void **this_prologue_cache) |
216 | { | |
d67ec5db AC |
217 | /* When unwinding a normal frame, the stack structure is determined |
218 | by analyzing the frame's function's code (be it using brute force | |
219 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
220 | frame, that simply isn't possible. The PC is either the program | |
221 | entry point, or some random address on the stack. Trying to use | |
222 | that PC to apply standard frame ID unwind techniques is just | |
223 | asking for trouble. */ | |
0c98cc2b | 224 | |
b89667eb | 225 | /* Don't bother unless there is at least one dummy frame. */ |
0c98cc2b | 226 | if (dummy_frame_stack != NULL) |
d67ec5db | 227 | { |
efc889c1 | 228 | struct dummy_frame *dummyframe; |
669fac23 DJ |
229 | /* Use an architecture specific method to extract this frame's |
230 | dummy ID, assuming it is a dummy frame. */ | |
efc889c1 YQ |
231 | struct frame_id this_id |
232 | = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); | |
b67a2c6f | 233 | struct dummy_frame_id dummy_id = { this_id, inferior_ptid }; |
0c98cc2b MS |
234 | |
235 | /* Use that ID to find the corresponding cache entry. */ | |
236 | for (dummyframe = dummy_frame_stack; | |
237 | dummyframe != NULL; | |
238 | dummyframe = dummyframe->next) | |
3c109c8b | 239 | { |
b67a2c6f | 240 | if (dummy_frame_id_eq (&dummyframe->id, &dummy_id)) |
0c98cc2b MS |
241 | { |
242 | struct dummy_frame_cache *cache; | |
9a619af0 | 243 | |
0c98cc2b | 244 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); |
16c381f0 JK |
245 | cache->prev_regcache = get_infcall_suspend_state_regcache |
246 | (dummyframe->caller_state); | |
0c98cc2b MS |
247 | cache->this_id = this_id; |
248 | (*this_prologue_cache) = cache; | |
249 | return 1; | |
250 | } | |
3c109c8b | 251 | } |
d67ec5db AC |
252 | } |
253 | return 0; | |
254 | } | |
255 | ||
9c1412c1 AC |
256 | /* Given a call-dummy dummy-frame, return the registers. Here the |
257 | register value is taken from the local copy of the register buffer. */ | |
258 | ||
669fac23 DJ |
259 | static struct value * |
260 | dummy_frame_prev_register (struct frame_info *this_frame, | |
6dc42492 | 261 | void **this_prologue_cache, |
669fac23 | 262 | int regnum) |
9c1412c1 | 263 | { |
d67ec5db | 264 | struct dummy_frame_cache *cache = (*this_prologue_cache); |
669fac23 DJ |
265 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
266 | struct value *reg_val; | |
267 | ||
268 | /* The dummy-frame sniffer always fills in the cache. */ | |
d67ec5db | 269 | gdb_assert (cache != NULL); |
9c1412c1 AC |
270 | |
271 | /* Describe the register's location. Generic dummy frames always | |
272 | have the register value in an ``expression''. */ | |
669fac23 DJ |
273 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
274 | ||
275 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
276 | constructs either a raw or pseudo register from the raw | |
277 | register cache. */ | |
278 | regcache_cooked_read (cache->prev_regcache, regnum, | |
279 | value_contents_writeable (reg_val)); | |
280 | return reg_val; | |
9c1412c1 AC |
281 | } |
282 | ||
b89667eb | 283 | /* Assuming that THIS_FRAME is a dummy, return its ID. That ID is |
6dc42492 | 284 | determined by examining the NEXT frame's unwound registers using |
669fac23 | 285 | the method dummy_id(). As a side effect, THIS dummy frame's |
7a9dd1b2 | 286 | dummy cache is located and saved in THIS_PROLOGUE_CACHE. */ |
494cca16 AC |
287 | |
288 | static void | |
669fac23 | 289 | dummy_frame_this_id (struct frame_info *this_frame, |
6dc42492 AC |
290 | void **this_prologue_cache, |
291 | struct frame_id *this_id) | |
c689142b | 292 | { |
d67ec5db AC |
293 | /* The dummy-frame sniffer always fills in the cache. */ |
294 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
9a619af0 | 295 | |
d67ec5db AC |
296 | gdb_assert (cache != NULL); |
297 | (*this_id) = cache->this_id; | |
c689142b AC |
298 | } |
299 | ||
39d7b0e2 | 300 | const struct frame_unwind dummy_frame_unwind = |
494cca16 | 301 | { |
7df05f2b | 302 | DUMMY_FRAME, |
8fbca658 | 303 | default_frame_unwind_stop_reason, |
6dc42492 | 304 | dummy_frame_this_id, |
d67ec5db AC |
305 | dummy_frame_prev_register, |
306 | NULL, | |
307 | dummy_frame_sniffer, | |
494cca16 AC |
308 | }; |
309 | ||
00905d52 AC |
310 | static void |
311 | fprint_dummy_frames (struct ui_file *file) | |
312 | { | |
313 | struct dummy_frame *s; | |
9a619af0 | 314 | |
00905d52 AC |
315 | for (s = dummy_frame_stack; s != NULL; s = s->next) |
316 | { | |
317 | gdb_print_host_address (s, file); | |
318 | fprintf_unfiltered (file, ":"); | |
00905d52 | 319 | fprintf_unfiltered (file, " id="); |
b67a2c6f YQ |
320 | fprint_frame_id (file, s->id.id); |
321 | fprintf_unfiltered (file, ", ptid=%s", | |
322 | target_pid_to_str (s->id.ptid)); | |
00905d52 AC |
323 | fprintf_unfiltered (file, "\n"); |
324 | } | |
325 | } | |
326 | ||
327 | static void | |
328 | maintenance_print_dummy_frames (char *args, int from_tty) | |
329 | { | |
330 | if (args == NULL) | |
331 | fprint_dummy_frames (gdb_stdout); | |
332 | else | |
333 | { | |
724b958c | 334 | struct cleanup *cleanups; |
00905d52 | 335 | struct ui_file *file = gdb_fopen (args, "w"); |
9a619af0 | 336 | |
00905d52 | 337 | if (file == NULL) |
e2e0b3e5 | 338 | perror_with_name (_("maintenance print dummy-frames")); |
724b958c | 339 | cleanups = make_cleanup_ui_file_delete (file); |
00905d52 | 340 | fprint_dummy_frames (file); |
724b958c | 341 | do_cleanups (cleanups); |
00905d52 AC |
342 | } |
343 | } | |
344 | ||
345 | extern void _initialize_dummy_frame (void); | |
346 | ||
347 | void | |
348 | _initialize_dummy_frame (void) | |
349 | { | |
350 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 351 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
352 | &maintenanceprintlist); |
353 | ||
a45ae3ed | 354 | observer_attach_inferior_created (cleanup_dummy_frames); |
00905d52 | 355 | } |