Commit | Line | Data |
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9c1412c1 AC |
1 | /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
2 | ||
3 | Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, | |
4ea2acf0 AC |
4 | 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free |
5 | 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 | |
11 | the Free Software Foundation; either version 2 of the License, or | |
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 | |
20 | along with this program; if not, write to the Free Software | |
21 | Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | Boston, MA 02111-1307, USA. */ | |
23 | ||
24 | ||
25 | #include "defs.h" | |
26 | #include "dummy-frame.h" | |
27 | #include "regcache.h" | |
28 | #include "frame.h" | |
29 | #include "inferior.h" | |
30 | #include "gdb_assert.h" | |
494cca16 | 31 | #include "frame-unwind.h" |
00905d52 AC |
32 | #include "command.h" |
33 | #include "gdbcmd.h" | |
96860204 | 34 | #include "gdb_string.h" |
9c1412c1 | 35 | |
90ba813f AC |
36 | static int pc_in_dummy_frame (CORE_ADDR pc); |
37 | ||
9c1412c1 AC |
38 | /* Dummy frame. This saves the processor state just prior to setting |
39 | up the inferior function call. Older targets save the registers | |
40 | on the target stack (but that really slows down function calls). */ | |
41 | ||
42 | struct dummy_frame | |
43 | { | |
44 | struct dummy_frame *next; | |
45 | ||
f18c5a73 AC |
46 | /* These values belong to the caller (the previous frame, the frame |
47 | that this unwinds back to). */ | |
9c1412c1 | 48 | CORE_ADDR pc; |
9c1412c1 | 49 | CORE_ADDR top; |
c689142b | 50 | struct frame_id id; |
9c1412c1 AC |
51 | struct regcache *regcache; |
52 | ||
53 | /* Address range of the call dummy code. Look for PC in the range | |
54 | [LO..HI) (after allowing for DECR_PC_AFTER_BREAK). */ | |
55 | CORE_ADDR call_lo; | |
56 | CORE_ADDR call_hi; | |
57 | }; | |
58 | ||
59 | static struct dummy_frame *dummy_frame_stack = NULL; | |
60 | ||
30a4a8e0 | 61 | /* Function: pc_in_call_dummy (pc) |
9c1412c1 AC |
62 | |
63 | Return true if the PC falls in a dummy frame created by gdb for an | |
64 | inferior call. The code below which allows DECR_PC_AFTER_BREAK is | |
65 | for infrun.c, which may give the function a PC without that | |
66 | subtracted out. */ | |
67 | ||
68 | int | |
30a4a8e0 | 69 | deprecated_pc_in_call_dummy (CORE_ADDR pc) |
5e0f933e AC |
70 | { |
71 | return pc_in_dummy_frame (pc); | |
72 | } | |
73 | ||
74 | /* Return non-zero if the PC falls in a dummy frame. | |
75 | ||
76 | The code below which allows DECR_PC_AFTER_BREAK is for infrun.c, | |
77 | which may give the function a PC without that subtracted out. | |
78 | ||
79 | FIXME: cagney/2002-11-23: This is silly. Surely "infrun.c" can | |
80 | figure out what the real PC (as in the resume address) is BEFORE | |
e4a2df64 | 81 | calling this function. */ |
5e0f933e | 82 | |
90ba813f | 83 | static int |
5e0f933e | 84 | pc_in_dummy_frame (CORE_ADDR pc) |
9c1412c1 AC |
85 | { |
86 | struct dummy_frame *dummyframe; | |
87 | for (dummyframe = dummy_frame_stack; | |
88 | dummyframe != NULL; | |
89 | dummyframe = dummyframe->next) | |
90 | { | |
91 | if ((pc >= dummyframe->call_lo) | |
92 | && (pc < dummyframe->call_hi + DECR_PC_AFTER_BREAK)) | |
93 | return 1; | |
94 | } | |
95 | return 0; | |
96 | } | |
97 | ||
96860204 AC |
98 | /* Push the caller's state, along with the dummy frame info, onto a |
99 | dummy-frame stack. */ | |
9c1412c1 AC |
100 | |
101 | void | |
96860204 AC |
102 | dummy_frame_push (struct regcache *caller_regcache, |
103 | const struct frame_id *dummy_id) | |
9c1412c1 AC |
104 | { |
105 | struct dummy_frame *dummy_frame; | |
9c1412c1 | 106 | |
96860204 AC |
107 | /* Check to see if there are stale dummy frames, perhaps left over |
108 | from when a longjump took us out of a function that was called by | |
109 | the debugger. */ | |
9c1412c1 AC |
110 | dummy_frame = dummy_frame_stack; |
111 | while (dummy_frame) | |
96860204 AC |
112 | /* FIXME: cagney/2004-08-02: Should just test IDs. */ |
113 | if (gdbarch_inner_than (current_gdbarch, dummy_frame->top, | |
114 | dummy_id->stack_addr)) | |
115 | /* Stale -- destroy! */ | |
9c1412c1 AC |
116 | { |
117 | dummy_frame_stack = dummy_frame->next; | |
118 | regcache_xfree (dummy_frame->regcache); | |
119 | xfree (dummy_frame); | |
120 | dummy_frame = dummy_frame_stack; | |
121 | } | |
122 | else | |
123 | dummy_frame = dummy_frame->next; | |
124 | ||
96860204 AC |
125 | dummy_frame = XZALLOC (struct dummy_frame); |
126 | dummy_frame->regcache = caller_regcache; | |
127 | dummy_frame->id = (*dummy_id); | |
128 | /* FIXME: cagney/2004-08-02: Retain for compatibility - trust the | |
129 | ID. */ | |
130 | dummy_frame->pc = dummy_id->code_addr; | |
131 | dummy_frame->top = dummy_id->stack_addr; | |
132 | dummy_frame->call_lo = dummy_id->code_addr + 0; | |
133 | dummy_frame->call_hi = dummy_id->code_addr + 1; | |
9c1412c1 AC |
134 | dummy_frame->next = dummy_frame_stack; |
135 | dummy_frame_stack = dummy_frame; | |
136 | } | |
137 | ||
d67ec5db AC |
138 | /* Return the dummy frame cache, it contains both the ID, and a |
139 | pointer to the regcache. */ | |
140 | struct dummy_frame_cache | |
141 | { | |
142 | struct frame_id this_id; | |
143 | struct regcache *prev_regcache; | |
144 | }; | |
145 | ||
146 | int | |
147 | dummy_frame_sniffer (const struct frame_unwind *self, | |
148 | struct frame_info *next_frame, | |
149 | void **this_prologue_cache) | |
150 | { | |
151 | struct dummy_frame *dummyframe; | |
152 | struct frame_id this_id; | |
153 | ||
154 | /* When unwinding a normal frame, the stack structure is determined | |
155 | by analyzing the frame's function's code (be it using brute force | |
156 | prologue analysis, or the dwarf2 CFI). In the case of a dummy | |
157 | frame, that simply isn't possible. The PC is either the program | |
158 | entry point, or some random address on the stack. Trying to use | |
159 | that PC to apply standard frame ID unwind techniques is just | |
160 | asking for trouble. */ | |
161 | /* Use an architecture specific method to extract the prev's dummy | |
162 | ID from the next frame. Note that this method uses | |
163 | frame_register_unwind to obtain the register values needed to | |
164 | determine the dummy frame's ID. */ | |
165 | this_id = gdbarch_unwind_dummy_id (get_frame_arch (next_frame), next_frame); | |
166 | ||
167 | /* Use that ID to find the corresponding cache entry. */ | |
168 | for (dummyframe = dummy_frame_stack; | |
169 | dummyframe != NULL; | |
170 | dummyframe = dummyframe->next) | |
171 | { | |
172 | /* Does the PC fall within the dummy frame's breakpoint | |
173 | instruction. If not, discard this one. */ | |
174 | if (!(this_id.code_addr >= dummyframe->call_lo | |
175 | && this_id.code_addr < dummyframe->call_hi)) | |
176 | continue; | |
177 | /* Does the FP match? "infcall.c" explicitly saved the | |
178 | top-of-stack before the inferior function call, assume | |
179 | unwind_dummy_id() returns that same stack value. */ | |
180 | if (this_id.stack_addr != dummyframe->top) | |
181 | continue; | |
182 | /* The FP matches this dummy frame. */ | |
183 | { | |
184 | struct dummy_frame_cache *cache; | |
185 | cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); | |
186 | cache->prev_regcache = dummyframe->regcache; | |
187 | cache->this_id = this_id; | |
188 | (*this_prologue_cache) = cache; | |
189 | return 1; | |
190 | } | |
191 | } | |
192 | return 0; | |
193 | } | |
194 | ||
9c1412c1 AC |
195 | /* Given a call-dummy dummy-frame, return the registers. Here the |
196 | register value is taken from the local copy of the register buffer. */ | |
197 | ||
494cca16 | 198 | static void |
6dc42492 AC |
199 | dummy_frame_prev_register (struct frame_info *next_frame, |
200 | void **this_prologue_cache, | |
201 | int regnum, int *optimized, | |
202 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
203 | int *realnum, void *bufferp) | |
9c1412c1 | 204 | { |
d67ec5db AC |
205 | /* The dummy-frame sniffer always fills in the cache. */ |
206 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
207 | gdb_assert (cache != NULL); | |
9c1412c1 AC |
208 | |
209 | /* Describe the register's location. Generic dummy frames always | |
210 | have the register value in an ``expression''. */ | |
211 | *optimized = 0; | |
212 | *lvalp = not_lval; | |
213 | *addrp = 0; | |
214 | *realnum = -1; | |
215 | ||
216 | /* If needed, find and return the value of the register. */ | |
217 | if (bufferp != NULL) | |
218 | { | |
9c1412c1 AC |
219 | /* Return the actual value. */ |
220 | /* Use the regcache_cooked_read() method so that it, on the fly, | |
221 | constructs either a raw or pseudo register from the raw | |
222 | register cache. */ | |
d67ec5db | 223 | regcache_cooked_read (cache->prev_regcache, regnum, bufferp); |
9c1412c1 AC |
224 | } |
225 | } | |
226 | ||
6dc42492 AC |
227 | /* Assuming that THIS frame is a dummy (remember, the NEXT and not |
228 | THIS frame is passed in), return the ID of THIS frame. That ID is | |
229 | determined by examining the NEXT frame's unwound registers using | |
230 | the method unwind_dummy_id(). As a side effect, THIS dummy frame's | |
231 | dummy cache is located and and saved in THIS_PROLOGUE_CACHE. */ | |
494cca16 AC |
232 | |
233 | static void | |
6dc42492 AC |
234 | dummy_frame_this_id (struct frame_info *next_frame, |
235 | void **this_prologue_cache, | |
236 | struct frame_id *this_id) | |
c689142b | 237 | { |
d67ec5db AC |
238 | /* The dummy-frame sniffer always fills in the cache. */ |
239 | struct dummy_frame_cache *cache = (*this_prologue_cache); | |
240 | gdb_assert (cache != NULL); | |
241 | (*this_id) = cache->this_id; | |
c689142b AC |
242 | } |
243 | ||
d67ec5db | 244 | static const struct frame_unwind dummy_frame_unwinder = |
494cca16 | 245 | { |
7df05f2b | 246 | DUMMY_FRAME, |
6dc42492 | 247 | dummy_frame_this_id, |
d67ec5db AC |
248 | dummy_frame_prev_register, |
249 | NULL, | |
250 | dummy_frame_sniffer, | |
494cca16 AC |
251 | }; |
252 | ||
d67ec5db AC |
253 | const struct frame_unwind *const dummy_frame_unwind = { |
254 | &dummy_frame_unwinder | |
255 | }; | |
00905d52 AC |
256 | |
257 | static void | |
258 | fprint_dummy_frames (struct ui_file *file) | |
259 | { | |
260 | struct dummy_frame *s; | |
261 | for (s = dummy_frame_stack; s != NULL; s = s->next) | |
262 | { | |
263 | gdb_print_host_address (s, file); | |
264 | fprintf_unfiltered (file, ":"); | |
265 | fprintf_unfiltered (file, " pc=0x%s", paddr (s->pc)); | |
00905d52 AC |
266 | fprintf_unfiltered (file, " top=0x%s", paddr (s->top)); |
267 | fprintf_unfiltered (file, " id="); | |
268 | fprint_frame_id (file, s->id); | |
269 | fprintf_unfiltered (file, " call_lo=0x%s", paddr (s->call_lo)); | |
270 | fprintf_unfiltered (file, " call_hi=0x%s", paddr (s->call_hi)); | |
271 | fprintf_unfiltered (file, "\n"); | |
272 | } | |
273 | } | |
274 | ||
275 | static void | |
276 | maintenance_print_dummy_frames (char *args, int from_tty) | |
277 | { | |
278 | if (args == NULL) | |
279 | fprint_dummy_frames (gdb_stdout); | |
280 | else | |
281 | { | |
282 | struct ui_file *file = gdb_fopen (args, "w"); | |
283 | if (file == NULL) | |
284 | perror_with_name ("maintenance print dummy-frames"); | |
285 | fprint_dummy_frames (file); | |
286 | ui_file_delete (file); | |
287 | } | |
288 | } | |
289 | ||
290 | extern void _initialize_dummy_frame (void); | |
291 | ||
292 | void | |
293 | _initialize_dummy_frame (void) | |
294 | { | |
295 | add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, | |
296 | "Print the contents of the internal dummy-frame stack.", | |
297 | &maintenanceprintlist); | |
298 | ||
299 | } |