GDB (xrefs)

/tmp/gdb-8.1/gdb/frame-unwind.c
Go to the documentation of this file.
1 /* Definitions for frame unwinder, for GDB, the GNU debugger.
2
3 Copyright (C) 2003-2018 Free Software Foundation, Inc.
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
9 the Free Software Foundation; either version 3 of the License, or
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
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20 #include "defs.h"
21 #include "frame.h"
22 #include "frame-unwind.h"
23 #include "dummy-frame.h"
24 #include "inline-frame.h"
25 #include "value.h"
26 #include "regcache.h"
27 #include "gdb_obstack.h"
28 #include "target.h"
29
30 static struct gdbarch_data *frame_unwind_data;
31
32 struct frame_unwind_table_entry
33 {
34 const struct frame_unwind *unwinder;
35 struct frame_unwind_table_entry *next;
36 };
37
38 struct frame_unwind_table
39 {
40 struct frame_unwind_table_entry *list;
41 /* The head of the OSABI part of the search list. */
42 struct frame_unwind_table_entry **osabi_head;
43 };
44
45 static void *
46 frame_unwind_init (struct obstack *obstack)
47 {
48 struct frame_unwind_table *table
49 = OBSTACK_ZALLOC (obstack, struct frame_unwind_table);
50
51 /* Start the table out with a few default sniffers. OSABI code
52 can't override this. */
53 table->list = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
54 table->list->unwinder = &dummy_frame_unwind;
55 table->list->next = OBSTACK_ZALLOC (obstack,
56 struct frame_unwind_table_entry);
57 table->list->next->unwinder = &inline_frame_unwind;
58 /* The insertion point for OSABI sniffers. */
59 table->osabi_head = &table->list->next->next;
60 return table;
61 }
62
63 void
64 frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
65 const struct frame_unwind *unwinder)
66 {
67 struct frame_unwind_table *table
68 = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
69 struct frame_unwind_table_entry *entry;
70
71 /* Insert the new entry at the start of the list. */
72 entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
73 entry->unwinder = unwinder;
74 entry->next = (*table->osabi_head);
75 (*table->osabi_head) = entry;
76 }
77
78 void
79 frame_unwind_append_unwinder (struct gdbarch *gdbarch,
80 const struct frame_unwind *unwinder)
81 {
82 struct frame_unwind_table *table
83 = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
84 struct frame_unwind_table_entry **ip;
85
86 /* Find the end of the list and insert the new entry there. */
87 for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next);
88 (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
89 (*ip)->unwinder = unwinder;
90 }
91
92 /* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for
93 THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME
94 unchanged and returns 0. */
95
96 static int
97 frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
98 const struct frame_unwind *unwinder)
99 {
100 int res = 0;
101
102 frame_prepare_for_sniffer (this_frame, unwinder);
103
104 TRY
105 {
106 res = unwinder->sniffer (unwinder, this_frame, this_cache);
107 }
108 CATCH (ex, RETURN_MASK_ALL)
109 {
110 /* Catch all exceptions, caused by either interrupt or error.
111 Reset *THIS_CACHE. */
112 *this_cache = NULL;
113 if (ex.error == NOT_AVAILABLE_ERROR)
114 {
115 /* This usually means that not even the PC is available,
116 thus most unwinders aren't able to determine if they're
117 the best fit. Keep trying. Fallback prologue unwinders
118 should always accept the frame. */
119 frame_cleanup_after_sniffer (this_frame);
120 return 0;
121 }
122 throw_exception (ex);
123 }
124 END_CATCH
125
126 if (res)
127 return 1;
128 else
129 {
130 /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
131 so. */
132 frame_cleanup_after_sniffer (this_frame);
133 return 0;
134 }
135 gdb_assert_not_reached ("frame_unwind_try_unwinder");
136 }
137
138 /* Iterate through sniffers for THIS_FRAME frame until one returns with an
139 unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
140 by this function. Possibly initialize THIS_CACHE. */
141
142 void
143 frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache)
144 {
145 struct gdbarch *gdbarch = get_frame_arch (this_frame);
146 struct frame_unwind_table *table
147 = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
148 struct frame_unwind_table_entry *entry;
149 const struct frame_unwind *unwinder_from_target;
150
151 unwinder_from_target = target_get_unwinder ();
152 if (unwinder_from_target != NULL
153 && frame_unwind_try_unwinder (this_frame, this_cache,
154 unwinder_from_target))
155 return;
156
157 unwinder_from_target = target_get_tailcall_unwinder ();
158 if (unwinder_from_target != NULL
159 && frame_unwind_try_unwinder (this_frame, this_cache,
160 unwinder_from_target))
161 return;
162
163 for (entry = table->list; entry != NULL; entry = entry->next)
164 if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder))
165 return;
166
167 internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed"));
168 }
169
170 /* A default frame sniffer which always accepts the frame. Used by
171 fallback prologue unwinders. */
172
173 int
174 default_frame_sniffer (const struct frame_unwind *self,
175 struct frame_info *this_frame,
176 void **this_prologue_cache)
177 {
178 return 1;
179 }
180
181 /* The default frame unwinder stop_reason callback. */
182
183 enum unwind_stop_reason
184 default_frame_unwind_stop_reason (struct frame_info *this_frame,
185 void **this_cache)
186 {
187 struct frame_id this_id = get_frame_id (this_frame);
188
189 if (frame_id_eq (this_id, outer_frame_id))
190 return UNWIND_OUTERMOST;
191 else
192 return UNWIND_NO_REASON;
193 }
194
195 /* Helper functions for value-based register unwinding. These return
196 a (possibly lazy) value of the appropriate type. */
197
198 /* Return a value which indicates that FRAME did not save REGNUM. */
199
200 struct value *
201 frame_unwind_got_optimized (struct frame_info *frame, int regnum)
202 {
203 struct gdbarch *gdbarch = frame_unwind_arch (frame);
204 struct type *type = register_type (gdbarch, regnum);
205 struct value *val;
206
207 /* Return an lval_register value, so that we print it as
208 "<not saved>". */
209 val = allocate_value_lazy (type);
210 set_value_lazy (val, 0);
211 mark_value_bytes_optimized_out (val, 0, TYPE_LENGTH (type));
212 VALUE_LVAL (val) = lval_register;
213 VALUE_REGNUM (val) = regnum;
214 VALUE_NEXT_FRAME_ID (val)
215 = get_frame_id (get_next_frame_sentinel_okay (frame));
216 return val;
217 }
218
219 /* Return a value which indicates that FRAME copied REGNUM into
220 register NEW_REGNUM. */
221
222 struct value *
223 frame_unwind_got_register (struct frame_info *frame,
224 int regnum, int new_regnum)
225 {
226 return value_of_register_lazy (frame, new_regnum);
227 }
228
229 /* Return a value which indicates that FRAME saved REGNUM in memory at
230 ADDR. */
231
232 struct value *
233 frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr)
234 {
235 struct gdbarch *gdbarch = frame_unwind_arch (frame);
236 struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr);
237
238 set_value_stack (v, 1);
239 return v;
240 }
241
242 /* Return a value which indicates that FRAME's saved version of
243 REGNUM has a known constant (computed) value of VAL. */
244
245 struct value *
246 frame_unwind_got_constant (struct frame_info *frame, int regnum,
247 ULONGEST val)
248 {
249 struct gdbarch *gdbarch = frame_unwind_arch (frame);
250 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
251 struct value *reg_val;
252
253 reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
254 store_unsigned_integer (value_contents_writeable (reg_val),
255 register_size (gdbarch, regnum), byte_order, val);
256 return reg_val;
257 }
258
259 struct value *
260 frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf)
261 {
262 struct gdbarch *gdbarch = frame_unwind_arch (frame);
263 struct value *reg_val;
264
265 reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
266 memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum));
267 return reg_val;
268 }
269
270 /* Return a value which indicates that FRAME's saved version of REGNUM
271 has a known constant (computed) value of ADDR. Convert the
272 CORE_ADDR to a target address if necessary. */
273
274 struct value *
275 frame_unwind_got_address (struct frame_info *frame, int regnum,
276 CORE_ADDR addr)
277 {
278 struct gdbarch *gdbarch = frame_unwind_arch (frame);
279 struct value *reg_val;
280
281 reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
282 pack_long (value_contents_writeable (reg_val),
283 register_type (gdbarch, regnum), addr);
284 return reg_val;
285 }
286
287 void
288 _initialize_frame_unwind (void)
289 {
290 frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init);
291 }
gdbarch
Definition: gdbarch.c:127
value_zero
struct value * value_zero(struct type *type, enum lval_type lv)
Definition: valops.c:847
frame_unwind_got_bytes
struct value * frame_unwind_got_bytes(struct frame_info *frame, int regnum, gdb_byte *buf)
Definition: frame-unwind.c:260
gdb_obstack.h
CORE_ADDR
bfd_vma CORE_ADDR
Definition: common-types.h:41
target_get_tailcall_unwinder
const struct frame_unwind * target_get_tailcall_unwinder(void)
Definition: target.c:3756
RETURN_MASK_ALL
Definition: common-exceptions.h:44
target_get_unwinder
const struct frame_unwind * target_get_unwinder(void)
Definition: target.c:3748
frame_unwind_got_memory
struct value * frame_unwind_got_memory(struct frame_info *frame, int regnum, CORE_ADDR addr)
Definition: frame-unwind.c:233
dummy_frame_unwind
const struct frame_unwind dummy_frame_unwind
Definition: dummy-frame.c:378
VALUE_NEXT_FRAME_ID
#define VALUE_NEXT_FRAME_ID(val)
Definition: value.h:441
frame_unwind_table_entry::next
struct frame_unwind_table_entry * next
Definition: frame-unwind.c:35
lval_register
Definition: defs.h:385
frame_cleanup_after_sniffer
void frame_cleanup_after_sniffer(struct frame_info *frame)
Definition: frame.c:2867
allocate_value_lazy
struct value * allocate_value_lazy(struct type *type)
Definition: value.c:916
internal_error
void internal_error(const char *file, int line, const char *fmt,...)
Definition: errors.c:50
frame_unwind::sniffer
frame_sniffer_ftype * sniffer
Definition: frame-unwind.h:155
set_value_lazy
void set_value_lazy(struct value *value, int val)
Definition: value.c:1389
frame_info
Definition: frame.c:85
unwind_stop_reason
unwind_stop_reason
Definition: frame.h:504
gdbarch_data_register_pre_init
struct gdbarch_data * gdbarch_data_register_pre_init(gdbarch_data_pre_init_ftype *pre_init)
Definition: gdbarch.c:5130
_
#define _(String)
Definition: gdb_locale.h:35
frame_prepare_for_sniffer
void frame_prepare_for_sniffer(struct frame_info *frame, const struct frame_unwind *unwind)
Definition: frame.c:2897
defs.h
END_CATCH
#define END_CATCH
Definition: common-exceptions.h:259
frame_unwind_prepend_unwinder
void frame_unwind_prepend_unwinder(struct gdbarch *gdbarch, const struct frame_unwind *unwinder)
Definition: frame-unwind.c:64
VALUE_LVAL
#define VALUE_LVAL(val)
Definition: value.h:414
frame_unwind_append_unwinder
void frame_unwind_append_unwinder(struct gdbarch *gdbarch, const struct frame_unwind *unwinder)
Definition: frame-unwind.c:79
GDBARCH_OBSTACK_ZALLOC
#define GDBARCH_OBSTACK_ZALLOC(GDBARCH, TYPE)
Definition: gdbarch.h:1709
frame_unwind_arch
struct gdbarch * frame_unwind_arch(struct frame_info *next_frame)
Definition: frame.c:2697
frame_unwind_got_constant
struct value * frame_unwind_got_constant(struct frame_info *frame, int regnum, ULONGEST val)
Definition: frame-unwind.c:246
frame_unwind_find_by_frame
void frame_unwind_find_by_frame(struct frame_info *this_frame, void **this_cache)
Definition: frame-unwind.c:143
NOT_AVAILABLE_ERROR
Definition: common-exceptions.h:82
TRY
#define TRY
Definition: common-exceptions.h:246
frame_id_eq
int frame_id_eq(struct frame_id l, struct frame_id r)
Definition: frame.c:674
inline-frame.h
get_frame_id
struct frame_id get_frame_id(struct frame_info *fi)
Definition: frame.c:520
CATCH
#define CATCH(EXCEPTION, MASK)
Definition: common-exceptions.h:254
frame_unwind_table::osabi_head
struct frame_unwind_table_entry ** osabi_head
Definition: frame-unwind.c:42
value_of_register_lazy
struct value * value_of_register_lazy(struct frame_info *frame, int regnum)
Definition: findvar.c:284
dummy-frame.h
frame_unwind_table_entry::unwinder
const struct frame_unwind * unwinder
Definition: frame-unwind.c:34
regcache.h
register_type
struct type * register_type(struct gdbarch *gdbarch, int regnum)
Definition: regcache.c:152
frame.h
gdb_assert_not_reached
#define gdb_assert_not_reached(message)
Definition: gdb_assert.h:55
gdbarch_byte_order
enum bfd_endian gdbarch_byte_order(struct gdbarch *gdbarch)
Definition: gdbarch.c:1509
type
Definition: gdbtypes.h:749
VALUE_REGNUM
#define VALUE_REGNUM(val)
Definition: value.h:451
inline_frame_unwind
const struct frame_unwind inline_frame_unwind
Definition: inline-frame.c:263
frame-unwind.h
default_frame_sniffer
int default_frame_sniffer(const struct frame_unwind *self, struct frame_info *this_frame, void **this_prologue_cache)
Definition: frame-unwind.c:174
value_contents_writeable
gdb_byte * value_contents_writeable(struct value *value)
Definition: value.c:1416
frame_unwind_try_unwinder
static int frame_unwind_try_unwinder(struct frame_info *this_frame, void **this_cache, const struct frame_unwind *unwinder)
Definition: frame-unwind.c:97
get_next_frame_sentinel_okay
struct frame_info * get_next_frame_sentinel_okay(struct frame_info *this_frame)
Definition: frame.c:1784
value_at_lazy
struct value * value_at_lazy(struct type *type, CORE_ADDR addr)
Definition: valops.c:944
_initialize_frame_unwind
void _initialize_frame_unwind(void)
Definition: frame-unwind.c:288
regnum
int regnum
Definition: aarch64-tdep.c:77
value
Definition: value.c:169
frame_unwind_got_optimized
struct value * frame_unwind_got_optimized(struct frame_info *frame, int regnum)
Definition: frame-unwind.c:201
throw_exception
void throw_exception(struct gdb_exception exception)
Definition: common-exceptions.c:312
gdb_byte
bfd_byte gdb_byte
Definition: common-types.h:38
mark_value_bytes_optimized_out
void mark_value_bytes_optimized_out(struct value *value, int offset, int length)
Definition: value.c:1448
frame_unwind_got_register
struct value * frame_unwind_got_register(struct frame_info *frame, int regnum, int new_regnum)
Definition: frame-unwind.c:223
target.h
value.h
frame_unwind
Definition: frame-unwind.h:144
frame_unwind_data
static struct gdbarch_data * frame_unwind_data
Definition: frame-unwind.c:30
set_value_stack
void set_value_stack(struct value *value, int val)
Definition: value.c:1401
frame_unwind_init
static void * frame_unwind_init(struct obstack *obstack)
Definition: frame-unwind.c:46
frame_unwind_table_entry
Definition: frame-unwind.c:32
ULONGEST
unsigned long long ULONGEST
Definition: common-types.h:53
default_frame_unwind_stop_reason
enum unwind_stop_reason default_frame_unwind_stop_reason(struct frame_info *this_frame, void **this_cache)
Definition: frame-unwind.c:184
outer_frame_id
const struct frame_id outer_frame_id
Definition: frame.c:577
frame_unwind_got_address
struct value * frame_unwind_got_address(struct frame_info *frame, int regnum, CORE_ADDR addr)
Definition: frame-unwind.c:275
register_size
int register_size(struct gdbarch *gdbarch, int regnum)
Definition: regcache.c:164
value_contents_raw
gdb_byte * value_contents_raw(struct value *value)
Definition: value.c:1158
frame_unwind_table::list
struct frame_unwind_table_entry * list
Definition: frame-unwind.c:40
OBSTACK_ZALLOC
#define OBSTACK_ZALLOC(OBSTACK, TYPE)
Definition: gdb_obstack.h:27
TYPE_LENGTH
#define TYPE_LENGTH(thistype)
Definition: gdbtypes.h:1235
gdbarch_data
Definition: gdbarch.c:5084
not_lval
Definition: defs.h:381
pack_long
void pack_long(gdb_byte *buf, struct type *type, LONGEST num)
Definition: value.c:3450
gdbarch::byte_order
enum bfd_endian byte_order
Definition: gdbarch.c:137
frame_id
Definition: frame.h:111
get_frame_arch
struct gdbarch * get_frame_arch(struct frame_info *this_frame)
Definition: frame.c:2691
frame_unwind_table
Definition: frame-unwind.c:38
store_unsigned_integer
static void store_unsigned_integer(gdb_byte *addr, int len, enum bfd_endian byte_order, ULONGEST val)
Definition: defs.h:604