Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
6aba47ca DJ |
3 | Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, |
4 | 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007 | |
5 | Free Software Foundation, Inc. | |
9c1412c1 AC |
6 | |
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 11 | the Free Software Foundation; either version 3 of the License, or |
9c1412c1 AC |
12 | (at your option) any later version. |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
9c1412c1 AC |
21 | |
22 | ||
23 | #include "defs.h" | |
24 | #include "dummy-frame.h" | |
25 | #include "regcache.h" | |
26 | #include "frame.h" | |
27 | #include "inferior.h" | |
28 | #include "gdb_assert.h" | |
494cca16 | 29 | #include "frame-unwind.h" |
00905d52 AC |
30 | #include "command.h" |
31 | #include "gdbcmd.h" | |
96860204 | 32 | #include "gdb_string.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 AC |
41 | /* This frame's ID. Must match the value returned by |
42 | gdbarch_unwind_dummy_id. */ | |
c689142b | 43 | struct frame_id id; |
3c109c8b | 44 | /* The caller's regcache. */ |
9c1412c1 | 45 | struct regcache *regcache; |
9c1412c1 AC |
46 | }; |
47 | ||
48 | static struct dummy_frame *dummy_frame_stack = NULL; | |
49 | ||
3c109c8b | 50 | /* Function: deprecated_pc_in_call_dummy (pc) |
5e0f933e | 51 | |
3c109c8b | 52 | Return non-zero if the PC falls in a dummy frame created by gdb for |
b798847d | 53 | an inferior call. The code below which allows gdbarch_decr_pc_after_break |
3c109c8b AC |
54 | is for infrun.c, which may give the function a PC without that |
55 | subtracted out. | |
5e0f933e AC |
56 | |
57 | FIXME: cagney/2002-11-23: This is silly. Surely "infrun.c" can | |
58 | figure out what the real PC (as in the resume address) is BEFORE | |
3c109c8b AC |
59 | calling this function. |
60 | ||
61 | NOTE: cagney/2004-08-02: I'm pretty sure that, with the introduction of | |
62 | infrun.c:adjust_pc_after_break (thanks), this function is now | |
63 | always called with a correctly adjusted PC! | |
5e0f933e | 64 | |
3c109c8b AC |
65 | NOTE: cagney/2004-08-02: Code should not need to call this. */ |
66 | ||
67 | int | |
68 | deprecated_pc_in_call_dummy (CORE_ADDR pc) | |
9c1412c1 AC |
69 | { |
70 | struct dummy_frame *dummyframe; | |
71 | for (dummyframe = dummy_frame_stack; | |
72 | dummyframe != NULL; | |
73 | dummyframe = dummyframe->next) | |
74 | { | |
3c109c8b | 75 | if ((pc >= dummyframe->id.code_addr) |
b798847d UW |
76 | && (pc <= dummyframe->id.code_addr |
77 | + gdbarch_decr_pc_after_break (current_gdbarch))) | |
9c1412c1 AC |
78 | return 1; |
79 | } | |
80 | return 0; | |
81 | } | |
82 | ||
96860204 AC |
83 | /* Push the caller's state, along with the dummy frame info, onto a |
84 | dummy-frame stack. */ | |
9c1412c1 AC |
85 | |
86 | void | |
96860204 AC |
87 | dummy_frame_push (struct regcache *caller_regcache, |
88 | const struct frame_id *dummy_id) | |
9c1412c1 AC |
89 | { |
90 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 91 | |
96860204 AC |
92 | /* Check to see if there are stale dummy frames, perhaps left over |
93 | from when a longjump took us out of a function that was called by | |
94 | the debugger. */ | |
9c1412c1 AC |
95 | dummy_frame = dummy_frame_stack; |
96 | while (dummy_frame) | |
96860204 | 97 | /* FIXME: cagney/2004-08-02: Should just test IDs. */ |
3c109c8b | 98 | if (frame_id_inner (dummy_frame->id, (*dummy_id))) |
96860204 | 99 | /* Stale -- destroy! */ |
9c1412c1 AC |
100 | { |
101 | dummy_frame_stack = dummy_frame->next; | |
102 | regcache_xfree (dummy_frame->regcache); | |
103 | xfree (dummy_frame); | |
104 | dummy_frame = dummy_frame_stack; | |
105 | } | |
106 | else | |
107 | dummy_frame = dummy_frame->next; | |
108 | ||
96860204 AC |
109 | dummy_frame = XZALLOC (struct dummy_frame); |
110 | dummy_frame->regcache = caller_regcache; | |
111 | dummy_frame->id = (*dummy_id); | |
9c1412c1 AC |
112 | dummy_frame->next = dummy_frame_stack; |
113 | dummy_frame_stack = dummy_frame; | |
114 | } | |
115 | ||
d67ec5db AC |
116 | /* Return the dummy frame cache, it contains both the ID, and a |
117 | pointer to the regcache. */ | |
118 | struct dummy_frame_cache | |
119 | { | |
120 | struct frame_id this_id; | |
121 | struct regcache *prev_regcache; | |
122 | }; | |
123 | ||
124 | int | |
125 | dummy_frame_sniffer (const struct frame_unwind *self, | |
126 | struct frame_info *next_frame, | |
127 | void **this_prologue_cache) | |
128 | { | |
129 | struct dummy_frame *dummyframe; | |
130 | struct frame_id this_id; | |
131 | ||
132 | /* When unwinding a normal frame, the stack structure is determined | |
133 | by analyzing the frame's function's code (be it using brute force | |
134 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
135 | frame, that simply isn't possible. The PC is either the program | |
136 | entry point, or some random address on the stack. Trying to use | |
137 | that PC to apply standard frame ID unwind techniques is just | |
138 | asking for trouble. */ | |
0c98cc2b MS |
139 | |
140 | /* Don't bother unles there is at least one dummy frame. */ | |
141 | if (dummy_frame_stack != NULL) | |
d67ec5db | 142 | { |
0c98cc2b MS |
143 | /* Use an architecture specific method to extract the prev's |
144 | dummy ID from the next frame. Note that this method uses | |
145 | frame_register_unwind to obtain the register values needed to | |
146 | determine the dummy frame's ID. */ | |
147 | this_id = gdbarch_unwind_dummy_id (get_frame_arch (next_frame), | |
148 | next_frame); | |
149 | ||
150 | /* Use that ID to find the corresponding cache entry. */ | |
151 | for (dummyframe = dummy_frame_stack; | |
152 | dummyframe != NULL; | |
153 | dummyframe = dummyframe->next) | |
3c109c8b | 154 | { |
0c98cc2b MS |
155 | if (frame_id_eq (dummyframe->id, this_id)) |
156 | { | |
157 | struct dummy_frame_cache *cache; | |
158 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); | |
159 | cache->prev_regcache = dummyframe->regcache; | |
160 | cache->this_id = this_id; | |
161 | (*this_prologue_cache) = cache; | |
162 | return 1; | |
163 | } | |
3c109c8b | 164 | } |
d67ec5db AC |
165 | } |
166 | return 0; | |
167 | } | |
168 | ||
9c1412c1 AC |
169 | /* Given a call-dummy dummy-frame, return the registers. Here the |
170 | register value is taken from the local copy of the register buffer. */ | |
171 | ||
494cca16 | 172 | static void |
6dc42492 AC |
173 | dummy_frame_prev_register (struct frame_info *next_frame, |
174 | void **this_prologue_cache, | |
175 | int regnum, int *optimized, | |
176 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
10c42a71 | 177 | int *realnum, gdb_byte *bufferp) |
9c1412c1 | 178 | { |
d67ec5db AC |
179 | /* The dummy-frame sniffer always fills in the cache. */ |
180 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
181 | gdb_assert (cache != NULL); | |
9c1412c1 AC |
182 | |
183 | /* Describe the register's location. Generic dummy frames always | |
184 | have the register value in an ``expression''. */ | |
185 | *optimized = 0; | |
186 | *lvalp = not_lval; | |
187 | *addrp = 0; | |
188 | *realnum = -1; | |
189 | ||
190 | /* If needed, find and return the value of the register. */ | |
191 | if (bufferp != NULL) | |
192 | { | |
9c1412c1 AC |
193 | /* Return the actual value. */ |
194 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
195 | constructs either a raw or pseudo register from the raw | |
196 | register cache. */ | |
d67ec5db | 197 | regcache_cooked_read (cache->prev_regcache, regnum, bufferp); |
9c1412c1 AC |
198 | } |
199 | } | |
200 | ||
6dc42492 AC |
201 | /* Assuming that THIS frame is a dummy (remember, the NEXT and not |
202 | THIS frame is passed in), return the ID of THIS frame. That ID is | |
203 | determined by examining the NEXT frame's unwound registers using | |
204 | the method unwind_dummy_id(). As a side effect, THIS dummy frame's | |
205 | dummy cache is located and and saved in THIS_PROLOGUE_CACHE. */ | |
494cca16 AC |
206 | |
207 | static void | |
6dc42492 AC |
208 | dummy_frame_this_id (struct frame_info *next_frame, |
209 | void **this_prologue_cache, | |
210 | struct frame_id *this_id) | |
c689142b | 211 | { |
d67ec5db AC |
212 | /* The dummy-frame sniffer always fills in the cache. */ |
213 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
214 | gdb_assert (cache != NULL); | |
215 | (*this_id) = cache->this_id; | |
c689142b AC |
216 | } |
217 | ||
d67ec5db | 218 | static const struct frame_unwind dummy_frame_unwinder = |
494cca16 | 219 | { |
7df05f2b | 220 | DUMMY_FRAME, |
6dc42492 | 221 | dummy_frame_this_id, |
d67ec5db AC |
222 | dummy_frame_prev_register, |
223 | NULL, | |
224 | dummy_frame_sniffer, | |
494cca16 AC |
225 | }; |
226 | ||
d67ec5db AC |
227 | const struct frame_unwind *const dummy_frame_unwind = { |
228 | &dummy_frame_unwinder | |
229 | }; | |
00905d52 AC |
230 | |
231 | static void | |
232 | fprint_dummy_frames (struct ui_file *file) | |
233 | { | |
234 | struct dummy_frame *s; | |
235 | for (s = dummy_frame_stack; s != NULL; s = s->next) | |
236 | { | |
237 | gdb_print_host_address (s, file); | |
238 | fprintf_unfiltered (file, ":"); | |
00905d52 AC |
239 | fprintf_unfiltered (file, " id="); |
240 | fprint_frame_id (file, s->id); | |
00905d52 AC |
241 | fprintf_unfiltered (file, "\n"); |
242 | } | |
243 | } | |
244 | ||
245 | static void | |
246 | maintenance_print_dummy_frames (char *args, int from_tty) | |
247 | { | |
248 | if (args == NULL) | |
249 | fprint_dummy_frames (gdb_stdout); | |
250 | else | |
251 | { | |
252 | struct ui_file *file = gdb_fopen (args, "w"); | |
253 | if (file == NULL) | |
e2e0b3e5 | 254 | perror_with_name (_("maintenance print dummy-frames")); |
00905d52 AC |
255 | fprint_dummy_frames (file); |
256 | ui_file_delete (file); | |
257 | } | |
258 | } | |
259 | ||
260 | extern void _initialize_dummy_frame (void); | |
261 | ||
262 | void | |
263 | _initialize_dummy_frame (void) | |
264 | { | |
265 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 266 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
267 | &maintenanceprintlist); |
268 | ||
269 | } |