Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
0b302171 | 3 | Copyright (C) 1986-2004, 2007-2012 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" |
9c1412c1 AC |
32 | |
33 | /* Dummy frame. This saves the processor state just prior to setting | |
34 | up the inferior function call. Older targets save the registers | |
35 | on the target stack (but that really slows down function calls). */ | |
36 | ||
37 | struct dummy_frame | |
38 | { | |
39 | struct dummy_frame *next; | |
3c109c8b | 40 | /* This frame's ID. Must match the value returned by |
669fac23 | 41 | gdbarch_dummy_id. */ |
c689142b | 42 | struct frame_id id; |
b89667eb | 43 | /* The caller's state prior to the call. */ |
16c381f0 | 44 | struct infcall_suspend_state *caller_state; |
9c1412c1 AC |
45 | }; |
46 | ||
47 | static struct dummy_frame *dummy_frame_stack = NULL; | |
48 | ||
3c109c8b | 49 | /* Function: deprecated_pc_in_call_dummy (pc) |
5e0f933e | 50 | |
3c109c8b | 51 | Return non-zero if the PC falls in a dummy frame created by gdb for |
b798847d | 52 | an inferior call. The code below which allows gdbarch_decr_pc_after_break |
3c109c8b AC |
53 | is for infrun.c, which may give the function a PC without that |
54 | subtracted out. | |
5e0f933e AC |
55 | |
56 | FIXME: cagney/2002-11-23: This is silly. Surely "infrun.c" can | |
57 | figure out what the real PC (as in the resume address) is BEFORE | |
3c109c8b AC |
58 | calling this function. |
59 | ||
60 | NOTE: cagney/2004-08-02: I'm pretty sure that, with the introduction of | |
61 | infrun.c:adjust_pc_after_break (thanks), this function is now | |
62 | always called with a correctly adjusted PC! | |
5e0f933e | 63 | |
3c109c8b AC |
64 | NOTE: cagney/2004-08-02: Code should not need to call this. */ |
65 | ||
66 | int | |
d80b854b | 67 | deprecated_pc_in_call_dummy (struct gdbarch *gdbarch, CORE_ADDR pc) |
9c1412c1 AC |
68 | { |
69 | struct dummy_frame *dummyframe; | |
9a619af0 | 70 | |
9c1412c1 AC |
71 | for (dummyframe = dummy_frame_stack; |
72 | dummyframe != NULL; | |
73 | dummyframe = dummyframe->next) | |
74 | { | |
3c109c8b | 75 | if ((pc >= dummyframe->id.code_addr) |
b798847d | 76 | && (pc <= dummyframe->id.code_addr |
d80b854b | 77 | + gdbarch_decr_pc_after_break (gdbarch))) |
9c1412c1 AC |
78 | return 1; |
79 | } | |
80 | return 0; | |
81 | } | |
82 | ||
b89667eb | 83 | /* Push the caller's state, along with the dummy frame info, onto the |
96860204 | 84 | dummy-frame stack. */ |
9c1412c1 AC |
85 | |
86 | void | |
16c381f0 | 87 | dummy_frame_push (struct infcall_suspend_state *caller_state, |
96860204 | 88 | const struct frame_id *dummy_id) |
9c1412c1 AC |
89 | { |
90 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 91 | |
96860204 | 92 | dummy_frame = XZALLOC (struct dummy_frame); |
b89667eb | 93 | dummy_frame->caller_state = caller_state; |
96860204 | 94 | dummy_frame->id = (*dummy_id); |
9c1412c1 AC |
95 | dummy_frame->next = dummy_frame_stack; |
96 | dummy_frame_stack = dummy_frame; | |
97 | } | |
98 | ||
b89667eb | 99 | /* Remove *DUMMY_PTR from the dummy frame stack. */ |
a45ae3ed | 100 | |
b89667eb DE |
101 | static void |
102 | remove_dummy_frame (struct dummy_frame **dummy_ptr) | |
a45ae3ed | 103 | { |
b89667eb | 104 | struct dummy_frame *dummy = *dummy_ptr; |
a45ae3ed | 105 | |
b89667eb | 106 | *dummy_ptr = dummy->next; |
16c381f0 | 107 | discard_infcall_suspend_state (dummy->caller_state); |
b89667eb | 108 | xfree (dummy); |
a45ae3ed UW |
109 | } |
110 | ||
b89667eb DE |
111 | /* Pop *DUMMY_PTR, restoring program state to that before the |
112 | frame was created. */ | |
a45ae3ed UW |
113 | |
114 | static void | |
b89667eb | 115 | pop_dummy_frame (struct dummy_frame **dummy_ptr) |
a45ae3ed | 116 | { |
b89667eb | 117 | struct dummy_frame *dummy; |
a45ae3ed | 118 | |
16c381f0 | 119 | restore_infcall_suspend_state ((*dummy_ptr)->caller_state); |
b89667eb | 120 | |
16c381f0 | 121 | /* restore_infcall_control_state frees inf_state, |
0963b4bd | 122 | all that remains is to pop *dummy_ptr. */ |
b89667eb DE |
123 | dummy = *dummy_ptr; |
124 | *dummy_ptr = dummy->next; | |
125 | xfree (dummy); | |
126 | ||
127 | /* We've made right mess of GDB's local state, just discard | |
128 | everything. */ | |
129 | reinit_frame_cache (); | |
130 | } | |
131 | ||
132 | /* Look up DUMMY_ID. | |
133 | Return NULL if not found. */ | |
134 | ||
135 | static struct dummy_frame ** | |
136 | lookup_dummy_frame (struct frame_id dummy_id) | |
137 | { | |
138 | struct dummy_frame **dp; | |
139 | ||
140 | for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next) | |
a45ae3ed | 141 | { |
b89667eb DE |
142 | if (frame_id_eq ((*dp)->id, dummy_id)) |
143 | return dp; | |
a45ae3ed UW |
144 | } |
145 | ||
b89667eb DE |
146 | return NULL; |
147 | } | |
148 | ||
149 | /* Pop the dummy frame DUMMY_ID, restoring program state to that before the | |
150 | frame was created. | |
151 | On return reinit_frame_cache has been called. | |
152 | If the frame isn't found, flag an internal error. | |
153 | ||
154 | NOTE: This can only pop the one frame, even if it is in the middle of the | |
155 | stack, because the other frames may be for different threads, and there's | |
156 | currently no way to tell which stack frame is for which thread. */ | |
157 | ||
158 | void | |
159 | dummy_frame_pop (struct frame_id dummy_id) | |
160 | { | |
161 | struct dummy_frame **dp; | |
162 | ||
163 | dp = lookup_dummy_frame (dummy_id); | |
164 | gdb_assert (dp != NULL); | |
165 | ||
166 | pop_dummy_frame (dp); | |
167 | } | |
168 | ||
169 | /* There may be stale dummy frames, perhaps left over from when a longjump took | |
170 | us out of a function that was called by the debugger. Clean them up at | |
171 | least once whenever we start a new inferior. */ | |
172 | ||
173 | static void | |
174 | cleanup_dummy_frames (struct target_ops *target, int from_tty) | |
175 | { | |
176 | while (dummy_frame_stack != NULL) | |
177 | remove_dummy_frame (&dummy_frame_stack); | |
a45ae3ed UW |
178 | } |
179 | ||
d67ec5db AC |
180 | /* Return the dummy frame cache, it contains both the ID, and a |
181 | pointer to the regcache. */ | |
182 | struct dummy_frame_cache | |
183 | { | |
184 | struct frame_id this_id; | |
185 | struct regcache *prev_regcache; | |
186 | }; | |
187 | ||
b89667eb | 188 | static int |
d67ec5db | 189 | dummy_frame_sniffer (const struct frame_unwind *self, |
669fac23 | 190 | struct frame_info *this_frame, |
d67ec5db AC |
191 | void **this_prologue_cache) |
192 | { | |
193 | struct dummy_frame *dummyframe; | |
194 | struct frame_id this_id; | |
195 | ||
196 | /* When unwinding a normal frame, the stack structure is determined | |
197 | by analyzing the frame's function's code (be it using brute force | |
198 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
199 | frame, that simply isn't possible. The PC is either the program | |
200 | entry point, or some random address on the stack. Trying to use | |
201 | that PC to apply standard frame ID unwind techniques is just | |
202 | asking for trouble. */ | |
0c98cc2b | 203 | |
b89667eb | 204 | /* Don't bother unless there is at least one dummy frame. */ |
0c98cc2b | 205 | if (dummy_frame_stack != NULL) |
d67ec5db | 206 | { |
669fac23 DJ |
207 | /* Use an architecture specific method to extract this frame's |
208 | dummy ID, assuming it is a dummy frame. */ | |
209 | this_id = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); | |
0c98cc2b MS |
210 | |
211 | /* Use that ID to find the corresponding cache entry. */ | |
212 | for (dummyframe = dummy_frame_stack; | |
213 | dummyframe != NULL; | |
214 | dummyframe = dummyframe->next) | |
3c109c8b | 215 | { |
0c98cc2b MS |
216 | if (frame_id_eq (dummyframe->id, this_id)) |
217 | { | |
218 | struct dummy_frame_cache *cache; | |
9a619af0 | 219 | |
0c98cc2b | 220 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); |
16c381f0 JK |
221 | cache->prev_regcache = get_infcall_suspend_state_regcache |
222 | (dummyframe->caller_state); | |
0c98cc2b MS |
223 | cache->this_id = this_id; |
224 | (*this_prologue_cache) = cache; | |
225 | return 1; | |
226 | } | |
3c109c8b | 227 | } |
d67ec5db AC |
228 | } |
229 | return 0; | |
230 | } | |
231 | ||
9c1412c1 AC |
232 | /* Given a call-dummy dummy-frame, return the registers. Here the |
233 | register value is taken from the local copy of the register buffer. */ | |
234 | ||
669fac23 DJ |
235 | static struct value * |
236 | dummy_frame_prev_register (struct frame_info *this_frame, | |
6dc42492 | 237 | void **this_prologue_cache, |
669fac23 | 238 | int regnum) |
9c1412c1 | 239 | { |
d67ec5db | 240 | struct dummy_frame_cache *cache = (*this_prologue_cache); |
669fac23 DJ |
241 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
242 | struct value *reg_val; | |
243 | ||
244 | /* The dummy-frame sniffer always fills in the cache. */ | |
d67ec5db | 245 | gdb_assert (cache != NULL); |
9c1412c1 AC |
246 | |
247 | /* Describe the register's location. Generic dummy frames always | |
248 | have the register value in an ``expression''. */ | |
669fac23 DJ |
249 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
250 | ||
251 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
252 | constructs either a raw or pseudo register from the raw | |
253 | register cache. */ | |
254 | regcache_cooked_read (cache->prev_regcache, regnum, | |
255 | value_contents_writeable (reg_val)); | |
256 | return reg_val; | |
9c1412c1 AC |
257 | } |
258 | ||
b89667eb | 259 | /* Assuming that THIS_FRAME is a dummy, return its ID. That ID is |
6dc42492 | 260 | determined by examining the NEXT frame's unwound registers using |
669fac23 | 261 | the method dummy_id(). As a side effect, THIS dummy frame's |
7a9dd1b2 | 262 | dummy cache is located and saved in THIS_PROLOGUE_CACHE. */ |
494cca16 AC |
263 | |
264 | static void | |
669fac23 | 265 | dummy_frame_this_id (struct frame_info *this_frame, |
6dc42492 AC |
266 | void **this_prologue_cache, |
267 | struct frame_id *this_id) | |
c689142b | 268 | { |
d67ec5db AC |
269 | /* The dummy-frame sniffer always fills in the cache. */ |
270 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
9a619af0 | 271 | |
d67ec5db AC |
272 | gdb_assert (cache != NULL); |
273 | (*this_id) = cache->this_id; | |
c689142b AC |
274 | } |
275 | ||
39d7b0e2 | 276 | const struct frame_unwind dummy_frame_unwind = |
494cca16 | 277 | { |
7df05f2b | 278 | DUMMY_FRAME, |
8fbca658 | 279 | default_frame_unwind_stop_reason, |
6dc42492 | 280 | dummy_frame_this_id, |
d67ec5db AC |
281 | dummy_frame_prev_register, |
282 | NULL, | |
283 | dummy_frame_sniffer, | |
494cca16 AC |
284 | }; |
285 | ||
00905d52 AC |
286 | static void |
287 | fprint_dummy_frames (struct ui_file *file) | |
288 | { | |
289 | struct dummy_frame *s; | |
9a619af0 | 290 | |
00905d52 AC |
291 | for (s = dummy_frame_stack; s != NULL; s = s->next) |
292 | { | |
293 | gdb_print_host_address (s, file); | |
294 | fprintf_unfiltered (file, ":"); | |
00905d52 AC |
295 | fprintf_unfiltered (file, " id="); |
296 | fprint_frame_id (file, s->id); | |
00905d52 AC |
297 | fprintf_unfiltered (file, "\n"); |
298 | } | |
299 | } | |
300 | ||
301 | static void | |
302 | maintenance_print_dummy_frames (char *args, int from_tty) | |
303 | { | |
304 | if (args == NULL) | |
305 | fprint_dummy_frames (gdb_stdout); | |
306 | else | |
307 | { | |
724b958c | 308 | struct cleanup *cleanups; |
00905d52 | 309 | struct ui_file *file = gdb_fopen (args, "w"); |
9a619af0 | 310 | |
00905d52 | 311 | if (file == NULL) |
e2e0b3e5 | 312 | perror_with_name (_("maintenance print dummy-frames")); |
724b958c | 313 | cleanups = make_cleanup_ui_file_delete (file); |
00905d52 | 314 | fprint_dummy_frames (file); |
724b958c | 315 | do_cleanups (cleanups); |
00905d52 AC |
316 | } |
317 | } | |
318 | ||
319 | extern void _initialize_dummy_frame (void); | |
320 | ||
321 | void | |
322 | _initialize_dummy_frame (void) | |
323 | { | |
324 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 325 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
326 | &maintenanceprintlist); |
327 | ||
a45ae3ed | 328 | observer_attach_inferior_created (cleanup_dummy_frames); |
00905d52 | 329 | } |