Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
6aba47ca | 3 | Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, |
9b254dd1 | 4 | 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008 |
6aba47ca | 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 | 41 | /* This frame's ID. Must match the value returned by |
669fac23 | 42 | gdbarch_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 | 89 | { |
09a7aba8 | 90 | struct gdbarch *gdbarch = get_regcache_arch (caller_regcache); |
9c1412c1 | 91 | struct dummy_frame *dummy_frame; |
9c1412c1 | 92 | |
96860204 AC |
93 | /* Check to see if there are stale dummy frames, perhaps left over |
94 | from when a longjump took us out of a function that was called by | |
95 | the debugger. */ | |
9c1412c1 AC |
96 | dummy_frame = dummy_frame_stack; |
97 | while (dummy_frame) | |
96860204 | 98 | /* FIXME: cagney/2004-08-02: Should just test IDs. */ |
09a7aba8 | 99 | if (frame_id_inner (gdbarch, dummy_frame->id, (*dummy_id))) |
96860204 | 100 | /* Stale -- destroy! */ |
9c1412c1 AC |
101 | { |
102 | dummy_frame_stack = dummy_frame->next; | |
103 | regcache_xfree (dummy_frame->regcache); | |
104 | xfree (dummy_frame); | |
105 | dummy_frame = dummy_frame_stack; | |
106 | } | |
107 | else | |
108 | dummy_frame = dummy_frame->next; | |
109 | ||
96860204 AC |
110 | dummy_frame = XZALLOC (struct dummy_frame); |
111 | dummy_frame->regcache = caller_regcache; | |
112 | dummy_frame->id = (*dummy_id); | |
9c1412c1 AC |
113 | dummy_frame->next = dummy_frame_stack; |
114 | dummy_frame_stack = dummy_frame; | |
115 | } | |
116 | ||
d67ec5db AC |
117 | /* Return the dummy frame cache, it contains both the ID, and a |
118 | pointer to the regcache. */ | |
119 | struct dummy_frame_cache | |
120 | { | |
121 | struct frame_id this_id; | |
122 | struct regcache *prev_regcache; | |
123 | }; | |
124 | ||
125 | int | |
126 | dummy_frame_sniffer (const struct frame_unwind *self, | |
669fac23 | 127 | struct frame_info *this_frame, |
d67ec5db AC |
128 | void **this_prologue_cache) |
129 | { | |
130 | struct dummy_frame *dummyframe; | |
131 | struct frame_id this_id; | |
132 | ||
133 | /* When unwinding a normal frame, the stack structure is determined | |
134 | by analyzing the frame's function's code (be it using brute force | |
135 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
136 | frame, that simply isn't possible. The PC is either the program | |
137 | entry point, or some random address on the stack. Trying to use | |
138 | that PC to apply standard frame ID unwind techniques is just | |
139 | asking for trouble. */ | |
0c98cc2b MS |
140 | |
141 | /* Don't bother unles there is at least one dummy frame. */ | |
142 | if (dummy_frame_stack != NULL) | |
d67ec5db | 143 | { |
669fac23 DJ |
144 | /* Use an architecture specific method to extract this frame's |
145 | dummy ID, assuming it is a dummy frame. */ | |
146 | this_id = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); | |
0c98cc2b MS |
147 | |
148 | /* Use that ID to find the corresponding cache entry. */ | |
149 | for (dummyframe = dummy_frame_stack; | |
150 | dummyframe != NULL; | |
151 | dummyframe = dummyframe->next) | |
3c109c8b | 152 | { |
0c98cc2b MS |
153 | if (frame_id_eq (dummyframe->id, this_id)) |
154 | { | |
155 | struct dummy_frame_cache *cache; | |
156 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); | |
157 | cache->prev_regcache = dummyframe->regcache; | |
158 | cache->this_id = this_id; | |
159 | (*this_prologue_cache) = cache; | |
160 | return 1; | |
161 | } | |
3c109c8b | 162 | } |
d67ec5db AC |
163 | } |
164 | return 0; | |
165 | } | |
166 | ||
9c1412c1 AC |
167 | /* Given a call-dummy dummy-frame, return the registers. Here the |
168 | register value is taken from the local copy of the register buffer. */ | |
169 | ||
669fac23 DJ |
170 | static struct value * |
171 | dummy_frame_prev_register (struct frame_info *this_frame, | |
6dc42492 | 172 | void **this_prologue_cache, |
669fac23 | 173 | int regnum) |
9c1412c1 | 174 | { |
d67ec5db | 175 | struct dummy_frame_cache *cache = (*this_prologue_cache); |
669fac23 DJ |
176 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
177 | struct value *reg_val; | |
178 | ||
179 | /* The dummy-frame sniffer always fills in the cache. */ | |
d67ec5db | 180 | gdb_assert (cache != NULL); |
9c1412c1 AC |
181 | |
182 | /* Describe the register's location. Generic dummy frames always | |
183 | have the register value in an ``expression''. */ | |
669fac23 DJ |
184 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
185 | ||
186 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
187 | constructs either a raw or pseudo register from the raw | |
188 | register cache. */ | |
189 | regcache_cooked_read (cache->prev_regcache, regnum, | |
190 | value_contents_writeable (reg_val)); | |
191 | return reg_val; | |
9c1412c1 AC |
192 | } |
193 | ||
669fac23 | 194 | /* Assuming that THIS frame is a dummy, return the ID of THIS frame. That ID is |
6dc42492 | 195 | determined by examining the NEXT frame's unwound registers using |
669fac23 | 196 | the method dummy_id(). As a side effect, THIS dummy frame's |
6dc42492 | 197 | dummy cache is located and and saved in THIS_PROLOGUE_CACHE. */ |
494cca16 AC |
198 | |
199 | static void | |
669fac23 | 200 | dummy_frame_this_id (struct frame_info *this_frame, |
6dc42492 AC |
201 | void **this_prologue_cache, |
202 | struct frame_id *this_id) | |
c689142b | 203 | { |
d67ec5db AC |
204 | /* The dummy-frame sniffer always fills in the cache. */ |
205 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
206 | gdb_assert (cache != NULL); | |
207 | (*this_id) = cache->this_id; | |
c689142b AC |
208 | } |
209 | ||
d67ec5db | 210 | static const struct frame_unwind dummy_frame_unwinder = |
494cca16 | 211 | { |
7df05f2b | 212 | DUMMY_FRAME, |
6dc42492 | 213 | dummy_frame_this_id, |
d67ec5db AC |
214 | dummy_frame_prev_register, |
215 | NULL, | |
216 | dummy_frame_sniffer, | |
494cca16 AC |
217 | }; |
218 | ||
d67ec5db AC |
219 | const struct frame_unwind *const dummy_frame_unwind = { |
220 | &dummy_frame_unwinder | |
221 | }; | |
00905d52 AC |
222 | |
223 | static void | |
224 | fprint_dummy_frames (struct ui_file *file) | |
225 | { | |
226 | struct dummy_frame *s; | |
227 | for (s = dummy_frame_stack; s != NULL; s = s->next) | |
228 | { | |
229 | gdb_print_host_address (s, file); | |
230 | fprintf_unfiltered (file, ":"); | |
00905d52 AC |
231 | fprintf_unfiltered (file, " id="); |
232 | fprint_frame_id (file, s->id); | |
00905d52 AC |
233 | fprintf_unfiltered (file, "\n"); |
234 | } | |
235 | } | |
236 | ||
237 | static void | |
238 | maintenance_print_dummy_frames (char *args, int from_tty) | |
239 | { | |
240 | if (args == NULL) | |
241 | fprint_dummy_frames (gdb_stdout); | |
242 | else | |
243 | { | |
244 | struct ui_file *file = gdb_fopen (args, "w"); | |
245 | if (file == NULL) | |
e2e0b3e5 | 246 | perror_with_name (_("maintenance print dummy-frames")); |
00905d52 AC |
247 | fprint_dummy_frames (file); |
248 | ui_file_delete (file); | |
249 | } | |
250 | } | |
251 | ||
252 | extern void _initialize_dummy_frame (void); | |
253 | ||
254 | void | |
255 | _initialize_dummy_frame (void) | |
256 | { | |
257 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
1a966eab | 258 | _("Print the contents of the internal dummy-frame stack."), |
00905d52 AC |
259 | &maintenanceprintlist); |
260 | ||
261 | } |