Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
28e7fd62 | 3 | Copyright (C) 1986-2013 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" | |
26 | #include "gdb_assert.h" | |
494cca16 | 27 | #include "frame-unwind.h" |
00905d52 AC |
28 | #include "command.h" |
29 | #include "gdbcmd.h" | |
96860204 | 30 | #include "gdb_string.h" |
a45ae3ed | 31 | #include "observer.h" |
e2e4d78b | 32 | #include "gdbthread.h" |
9c1412c1 AC |
33 | |
34 | /* Dummy frame. This saves the processor state just prior to setting | |
35 | up the inferior function call. Older targets save the registers | |
36 | on the target stack (but that really slows down function calls). */ | |
37 | ||
38 | struct dummy_frame | |
39 | { | |
40 | struct dummy_frame *next; | |
3c109c8b | 41 | /* This frame's ID. Must match the value returned by |
669fac23 | 42 | gdbarch_dummy_id. */ |
c689142b | 43 | struct frame_id id; |
b89667eb | 44 | /* The caller's state prior to the call. */ |
16c381f0 | 45 | struct infcall_suspend_state *caller_state; |
9c1412c1 AC |
46 | }; |
47 | ||
48 | static struct dummy_frame *dummy_frame_stack = NULL; | |
49 | ||
b89667eb | 50 | /* Push the caller's state, along with the dummy frame info, onto the |
96860204 | 51 | dummy-frame stack. */ |
9c1412c1 AC |
52 | |
53 | void | |
16c381f0 | 54 | dummy_frame_push (struct infcall_suspend_state *caller_state, |
96860204 | 55 | const struct frame_id *dummy_id) |
9c1412c1 AC |
56 | { |
57 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 58 | |
96860204 | 59 | dummy_frame = XZALLOC (struct dummy_frame); |
b89667eb | 60 | dummy_frame->caller_state = caller_state; |
96860204 | 61 | dummy_frame->id = (*dummy_id); |
9c1412c1 AC |
62 | dummy_frame->next = dummy_frame_stack; |
63 | dummy_frame_stack = dummy_frame; | |
64 | } | |
65 | ||
b89667eb | 66 | /* Remove *DUMMY_PTR from the dummy frame stack. */ |
a45ae3ed | 67 | |
b89667eb DE |
68 | static void |
69 | remove_dummy_frame (struct dummy_frame **dummy_ptr) | |
a45ae3ed | 70 | { |
b89667eb | 71 | struct dummy_frame *dummy = *dummy_ptr; |
a45ae3ed | 72 | |
b89667eb | 73 | *dummy_ptr = dummy->next; |
16c381f0 | 74 | discard_infcall_suspend_state (dummy->caller_state); |
b89667eb | 75 | xfree (dummy); |
a45ae3ed UW |
76 | } |
77 | ||
e2e4d78b JK |
78 | /* Delete any breakpoint B which is a momentary breakpoint for return from |
79 | inferior call matching DUMMY_VOIDP. */ | |
80 | ||
81 | static int | |
82 | pop_dummy_frame_bpt (struct breakpoint *b, void *dummy_voidp) | |
83 | { | |
84 | struct dummy_frame *dummy = dummy_voidp; | |
85 | ||
86 | if (b->thread == pid_to_thread_id (inferior_ptid) | |
87 | && b->disposition == disp_del && frame_id_eq (b->frame_id, dummy->id)) | |
88 | { | |
89 | while (b->related_breakpoint != b) | |
90 | delete_breakpoint (b->related_breakpoint); | |
91 | ||
92 | delete_breakpoint (b); | |
93 | ||
94 | /* Stop the traversal. */ | |
95 | return 1; | |
96 | } | |
97 | ||
98 | /* Continue the traversal. */ | |
99 | return 0; | |
100 | } | |
101 | ||
b89667eb DE |
102 | /* Pop *DUMMY_PTR, restoring program state to that before the |
103 | frame was created. */ | |
a45ae3ed UW |
104 | |
105 | static void | |
b89667eb | 106 | pop_dummy_frame (struct dummy_frame **dummy_ptr) |
a45ae3ed | 107 | { |
e2e4d78b JK |
108 | struct dummy_frame *dummy = *dummy_ptr; |
109 | ||
110 | restore_infcall_suspend_state (dummy->caller_state); | |
a45ae3ed | 111 | |
e2e4d78b | 112 | iterate_over_breakpoints (pop_dummy_frame_bpt, dummy); |
b89667eb | 113 | |
16c381f0 | 114 | /* restore_infcall_control_state frees inf_state, |
0963b4bd | 115 | all that remains is to pop *dummy_ptr. */ |
b89667eb DE |
116 | *dummy_ptr = dummy->next; |
117 | xfree (dummy); | |
118 | ||
119 | /* We've made right mess of GDB's local state, just discard | |
120 | everything. */ | |
121 | reinit_frame_cache (); | |
122 | } | |
123 | ||
124 | /* Look up DUMMY_ID. | |
125 | Return NULL if not found. */ | |
126 | ||
127 | static struct dummy_frame ** | |
128 | lookup_dummy_frame (struct frame_id dummy_id) | |
129 | { | |
130 | struct dummy_frame **dp; | |
131 | ||
132 | for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next) | |
a45ae3ed | 133 | { |
b89667eb DE |
134 | if (frame_id_eq ((*dp)->id, dummy_id)) |
135 | return dp; | |
a45ae3ed UW |
136 | } |
137 | ||
b89667eb DE |
138 | return NULL; |
139 | } | |
140 | ||
141 | /* Pop the dummy frame DUMMY_ID, restoring program state to that before the | |
142 | frame was created. | |
143 | On return reinit_frame_cache has been called. | |
144 | If the frame isn't found, flag an internal error. | |
145 | ||
146 | NOTE: This can only pop the one frame, even if it is in the middle of the | |
147 | stack, because the other frames may be for different threads, and there's | |
148 | currently no way to tell which stack frame is for which thread. */ | |
149 | ||
150 | void | |
151 | dummy_frame_pop (struct frame_id dummy_id) | |
152 | { | |
153 | struct dummy_frame **dp; | |
154 | ||
155 | dp = lookup_dummy_frame (dummy_id); | |
156 | gdb_assert (dp != NULL); | |
157 | ||
158 | pop_dummy_frame (dp); | |
159 | } | |
160 | ||
e2e4d78b JK |
161 | /* Drop dummy frame DUMMY_ID. Do nothing if it is not found. Do not restore |
162 | its state into inferior, just free its memory. */ | |
163 | ||
164 | void | |
165 | dummy_frame_discard (struct frame_id dummy_id) | |
166 | { | |
167 | struct dummy_frame **dp; | |
168 | ||
169 | dp = lookup_dummy_frame (dummy_id); | |
170 | if (dp) | |
171 | remove_dummy_frame (dp); | |
172 | } | |
173 | ||
174 | /* There may be stale dummy frames, perhaps left over from when an uncaught | |
175 | longjmp took us out of a function that was called by the debugger. Clean | |
176 | them up at least once whenever we start a new inferior. */ | |
b89667eb DE |
177 | |
178 | static void | |
179 | cleanup_dummy_frames (struct target_ops *target, int from_tty) | |
180 | { | |
181 | while (dummy_frame_stack != NULL) | |
182 | remove_dummy_frame (&dummy_frame_stack); | |
a45ae3ed UW |
183 | } |
184 | ||
d67ec5db AC |
185 | /* Return the dummy frame cache, it contains both the ID, and a |
186 | pointer to the regcache. */ | |
187 | struct dummy_frame_cache | |
188 | { | |
189 | struct frame_id this_id; | |
190 | struct regcache *prev_regcache; | |
191 | }; | |
192 | ||
b89667eb | 193 | static int |
d67ec5db | 194 | dummy_frame_sniffer (const struct frame_unwind *self, |
669fac23 | 195 | struct frame_info *this_frame, |
d67ec5db AC |
196 | void **this_prologue_cache) |
197 | { | |
198 | struct dummy_frame *dummyframe; | |
199 | struct frame_id this_id; | |
200 | ||
201 | /* When unwinding a normal frame, the stack structure is determined | |
202 | by analyzing the frame's function's code (be it using brute force | |
203 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
204 | frame, that simply isn't possible. The PC is either the program | |
205 | entry point, or some random address on the stack. Trying to use | |
206 | that PC to apply standard frame ID unwind techniques is just | |
207 | asking for trouble. */ | |
0c98cc2b | 208 | |
b89667eb | 209 | /* Don't bother unless there is at least one dummy frame. */ |
0c98cc2b | 210 | if (dummy_frame_stack != NULL) |
d67ec5db | 211 | { |
669fac23 DJ |
212 | /* Use an architecture specific method to extract this frame's |
213 | dummy ID, assuming it is a dummy frame. */ | |
214 | this_id = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); | |
0c98cc2b MS |
215 | |
216 | /* Use that ID to find the corresponding cache entry. */ | |
217 | for (dummyframe = dummy_frame_stack; | |
218 | dummyframe != NULL; | |
219 | dummyframe = dummyframe->next) | |
3c109c8b | 220 | { |
0c98cc2b MS |
221 | if (frame_id_eq (dummyframe->id, this_id)) |
222 | { | |
223 | struct dummy_frame_cache *cache; | |
9a619af0 | 224 | |
0c98cc2b | 225 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); |
16c381f0 JK |
226 | cache->prev_regcache = get_infcall_suspend_state_regcache |
227 | (dummyframe->caller_state); | |
0c98cc2b MS |
228 | cache->this_id = this_id; |
229 | (*this_prologue_cache) = cache; | |
230 | return 1; | |
231 | } | |
3c109c8b | 232 | } |
d67ec5db AC |
233 | } |
234 | return 0; | |
235 | } | |
236 | ||
9c1412c1 AC |
237 | /* Given a call-dummy dummy-frame, return the registers. Here the |
238 | register value is taken from the local copy of the register buffer. */ | |
239 | ||
669fac23 DJ |
240 | static struct value * |
241 | dummy_frame_prev_register (struct frame_info *this_frame, | |
6dc42492 | 242 | void **this_prologue_cache, |
669fac23 | 243 | int regnum) |
9c1412c1 | 244 | { |
d67ec5db | 245 | struct dummy_frame_cache *cache = (*this_prologue_cache); |
669fac23 DJ |
246 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
247 | struct value *reg_val; | |
248 | ||
249 | /* The dummy-frame sniffer always fills in the cache. */ | |
d67ec5db | 250 | gdb_assert (cache != NULL); |
9c1412c1 AC |
251 | |
252 | /* Describe the register's location. Generic dummy frames always | |
253 | have the register value in an ``expression''. */ | |
669fac23 DJ |
254 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
255 | ||
256 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
257 | constructs either a raw or pseudo register from the raw | |
258 | register cache. */ | |
259 | regcache_cooked_read (cache->prev_regcache, regnum, | |
260 | value_contents_writeable (reg_val)); | |
261 | return reg_val; | |
9c1412c1 AC |
262 | } |
263 | ||
b89667eb | 264 | /* Assuming that THIS_FRAME is a dummy, return its ID. That ID is |
6dc42492 | 265 | determined by examining the NEXT frame's unwound registers using |
669fac23 | 266 | the method dummy_id(). As a side effect, THIS dummy frame's |
7a9dd1b2 | 267 | dummy cache is located and saved in THIS_PROLOGUE_CACHE. */ |
494cca16 AC |
268 | |
269 | static void | |
669fac23 | 270 | dummy_frame_this_id (struct frame_info *this_frame, |
6dc42492 AC |
271 | void **this_prologue_cache, |
272 | struct frame_id *this_id) | |
c689142b | 273 | { |
d67ec5db AC |
274 | /* The dummy-frame sniffer always fills in the cache. */ |
275 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
9a619af0 | 276 | |
d67ec5db AC |
277 | gdb_assert (cache != NULL); |
278 | (*this_id) = cache->this_id; | |
c689142b AC |
279 | } |
280 | ||
39d7b0e2 | 281 | const struct frame_unwind dummy_frame_unwind = |
494cca16 | 282 | { |
7df05f2b | 283 | DUMMY_FRAME, |
8fbca658 | 284 | default_frame_unwind_stop_reason, |
6dc42492 | 285 | dummy_frame_this_id, |
d67ec5db AC |
286 | dummy_frame_prev_register, |
287 | NULL, | |
288 | dummy_frame_sniffer, | |
494cca16 AC |
289 | }; |
290 | ||
00905d52 AC |
291 | static void |
292 | fprint_dummy_frames (struct ui_file *file) | |
293 | { | |
294 | struct dummy_frame *s; | |
9a619af0 | 295 | |
00905d52 AC |
296 | for (s = dummy_frame_stack; s != NULL; s = s->next) |
297 | { | |
298 | gdb_print_host_address (s, file); | |
299 | fprintf_unfiltered (file, ":"); | |
00905d52 AC |
300 | fprintf_unfiltered (file, " id="); |
301 | fprint_frame_id (file, s->id); | |
00905d52 AC |
302 | fprintf_unfiltered (file, "\n"); |
303 | } | |
304 | } | |
305 | ||
306 | static void | |
307 | maintenance_print_dummy_frames (char *args, int from_tty) | |
308 | { | |
309 | if (args == NULL) | |
310 | fprint_dummy_frames (gdb_stdout); | |
311 | else | |
312 | { | |
724b958c | 313 | struct cleanup *cleanups; |
00905d52 | 314 | struct ui_file *file = gdb_fopen (args, "w"); |
9a619af0 | 315 | |
00905d52 | 316 | if (file == NULL) |
e2e0b3e5 | 317 | perror_with_name (_("maintenance print dummy-frames")); |
724b958c | 318 | cleanups = make_cleanup_ui_file_delete (file); |
00905d52 | 319 | fprint_dummy_frames (file); |
724b958c | 320 | do_cleanups (cleanups); |
00905d52 AC |
321 | } |
322 | } | |
323 | ||
324 | extern void _initialize_dummy_frame (void); | |
325 | ||
326 | void | |
327 | _initialize_dummy_frame (void) | |
328 | { | |
329 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 330 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
331 | &maintenanceprintlist); |
332 | ||
a45ae3ed | 333 | observer_attach_inferior_created (cleanup_dummy_frames); |
00905d52 | 334 | } |