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/tmp/gdb-7.10/gdb/tramp-frame.c
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1 /* Signal trampoline unwinder, for GDB the GNU Debugger.
2 
3  Copyright (C) 2004-2015 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 "tramp-frame.h"
22 #include "frame-unwind.h"
23 #include "gdbcore.h"
24 #include "symtab.h"
25 #include "objfiles.h"
26 #include "target.h"
27 #include "trad-frame.h"
28 #include "frame-base.h"
29 
30 struct frame_data
31 {
32  const struct tramp_frame *tramp_frame;
33 };
34 
36 {
38  const struct tramp_frame *tramp_frame;
40 };
41 
42 static struct trad_frame_cache *
44  void **this_cache)
45 {
46  struct tramp_frame_cache *tramp_cache = (*this_cache);
47 
48  if (tramp_cache->trad_cache == NULL)
49  {
50  tramp_cache->trad_cache = trad_frame_cache_zalloc (this_frame);
51  tramp_cache->tramp_frame->init (tramp_cache->tramp_frame,
52  this_frame,
53  tramp_cache->trad_cache,
54  tramp_cache->func);
55  }
56  return tramp_cache->trad_cache;
57 }
58 
59 static void
60 tramp_frame_this_id (struct frame_info *this_frame,
61  void **this_cache,
62  struct frame_id *this_id)
63 {
64  struct trad_frame_cache *trad_cache
65  = tramp_frame_cache (this_frame, this_cache);
66 
67  trad_frame_get_id (trad_cache, this_id);
68 }
69 
70 static struct value *
72  void **this_cache,
73  int prev_regnum)
74 {
75  struct trad_frame_cache *trad_cache
76  = tramp_frame_cache (this_frame, this_cache);
77 
78  return trad_frame_get_register (trad_cache, this_frame, prev_regnum);
79 }
80 
81 static CORE_ADDR
82 tramp_frame_start (const struct tramp_frame *tramp,
83  struct frame_info *this_frame, CORE_ADDR pc)
84 {
85  struct gdbarch *gdbarch = get_frame_arch (this_frame);
86  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
87  int ti;
88 
89  /* Check if we can use this trampoline. */
90  if (tramp->validate && !tramp->validate (tramp, this_frame, &pc))
91  return 0;
92 
93  /* Search through the trampoline for one that matches the
94  instruction sequence around PC. */
95  for (ti = 0; tramp->insn[ti].bytes != TRAMP_SENTINEL_INSN; ti++)
96  {
97  CORE_ADDR func = pc - tramp->insn_size * ti;
98  int i;
99 
100  for (i = 0; 1; i++)
101  {
102  gdb_byte buf[sizeof (tramp->insn[0])];
103  ULONGEST insn;
104 
105  if (tramp->insn[i].bytes == TRAMP_SENTINEL_INSN)
106  return func;
107  if (!safe_frame_unwind_memory (this_frame,
108  func + i * tramp->insn_size,
109  buf, tramp->insn_size))
110  break;
111  insn = extract_unsigned_integer (buf, tramp->insn_size, byte_order);
112  if (tramp->insn[i].bytes != (insn & tramp->insn[i].mask))
113  break;
114  }
115  }
116  /* Trampoline doesn't match. */
117  return 0;
118 }
119 
120 static int
121 tramp_frame_sniffer (const struct frame_unwind *self,
122  struct frame_info *this_frame,
123  void **this_cache)
124 {
125  const struct tramp_frame *tramp = self->unwind_data->tramp_frame;
126  CORE_ADDR pc = get_frame_pc (this_frame);
127  CORE_ADDR func;
128  struct tramp_frame_cache *tramp_cache;
129 
130  /* tausq/2004-12-12: We used to assume if pc has a name or is in a valid
131  section, then this is not a trampoline. However, this assumption is
132  false on HPUX which has a signal trampoline that has a name; it can
133  also be false when using an alternative signal stack. */
134  func = tramp_frame_start (tramp, this_frame, pc);
135  if (func == 0)
136  return 0;
137  tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache);
138  tramp_cache->func = func;
139  tramp_cache->tramp_frame = tramp;
140  (*this_cache) = tramp_cache;
141  return 1;
142 }
143 
144 void
146  const struct tramp_frame *tramp_frame)
147 {
148  struct frame_data *data;
149  struct frame_unwind *unwinder;
150  int i;
151 
152  /* Check that the instruction sequence contains a sentinel. */
153  for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++)
154  {
155  if (tramp_frame->insn[i].bytes == TRAMP_SENTINEL_INSN)
156  break;
157  }
158  gdb_assert (i < ARRAY_SIZE (tramp_frame->insn));
159  gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes));
160 
161  data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data);
162  unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind);
163 
164  data->tramp_frame = tramp_frame;
165  unwinder->type = tramp_frame->frame_type;
166  unwinder->unwind_data = data;
167  unwinder->sniffer = tramp_frame_sniffer;
169  unwinder->this_id = tramp_frame_this_id;
171  frame_unwind_prepend_unwinder (gdbarch, unwinder);
172 }
ULONGEST extract_unsigned_integer(const gdb_byte *, int, enum bfd_endian)
Definition: findvar.c:84
static CORE_ADDR tramp_frame_start(const struct tramp_frame *tramp, struct frame_info *this_frame, CORE_ADDR pc)
Definition: tramp-frame.c:82
CORE_ADDR get_frame_pc(struct frame_info *frame)
Definition: frame.c:2217
bfd_vma CORE_ADDR
Definition: common-types.h:41
enum frame_type type
Definition: frame-unwind.h:147
#define TRAMP_SENTINEL_INSN
Definition: tramp-frame.h:44
ULONGEST bytes
Definition: tramp-frame.h:63
void(* func)(char *)
static int tramp_frame_sniffer(const struct frame_unwind *self, struct frame_info *this_frame, void **this_cache)
Definition: tramp-frame.c:121
frame_prev_register_ftype * prev_register
Definition: frame-unwind.h:152
frame_sniffer_ftype * sniffer
Definition: frame-unwind.h:154
void frame_unwind_prepend_unwinder(struct gdbarch *gdbarch, const struct frame_unwind *unwinder)
Definition: frame-unwind.c:64
#define FRAME_OBSTACK_ZALLOC(TYPE)
Definition: frame.h:660
struct trad_frame_cache * trad_cache
Definition: tramp-frame.c:39
#define GDBARCH_OBSTACK_ZALLOC(GDBARCH, TYPE)
Definition: gdbarch.h:1615
static void tramp_frame_this_id(struct frame_info *this_frame, void **this_cache, struct frame_id *this_id)
Definition: tramp-frame.c:60
void trad_frame_get_id(struct trad_frame_cache *this_trad_cache, struct frame_id *this_id)
Definition: trad-frame.c:171
static struct trad_frame_cache * tramp_frame_cache(struct frame_info *this_frame, void **this_cache)
Definition: tramp-frame.c:43
int safe_frame_unwind_memory(struct frame_info *this_frame, CORE_ADDR addr, gdb_byte *buf, int len)
Definition: frame.c:2525
frame_unwind_stop_reason_ftype * stop_reason
Definition: frame-unwind.h:150
enum bfd_endian gdbarch_byte_order(struct gdbarch *gdbarch)
Definition: gdbarch.c:1420
static struct value * tramp_frame_prev_register(struct frame_info *this_frame, void **this_cache, int prev_regnum)
Definition: tramp-frame.c:71
const struct tramp_frame * tramp_frame
Definition: tramp-frame.c:38
#define gdb_assert(expr)
Definition: gdb_assert.h:33
struct trad_frame_cache * trad_frame_cache_zalloc(struct frame_info *this_frame)
Definition: trad-frame.c:36
enum frame_type frame_type
Definition: tramp-frame.h:50
struct frame_info * this_frame
Definition: trad-frame.c:29
ULONGEST mask
Definition: tramp-frame.h:64
Definition: value.c:172
const struct tramp_frame * tramp_frame
Definition: tramp-frame.c:32
struct tramp_frame::@170 insn[48]
bfd_byte gdb_byte
Definition: common-types.h:38
void tramp_frame_prepend_unwinder(struct gdbarch *gdbarch, const struct tramp_frame *tramp_frame)
Definition: tramp-frame.c:145
void(* init)(const struct tramp_frame *self, struct frame_info *this_frame, struct trad_frame_cache *this_cache, CORE_ADDR func)
Definition: tramp-frame.h:68
CORE_ADDR func
Definition: tramp-frame.c:37
unsigned long long ULONGEST
Definition: common-types.h:53
enum unwind_stop_reason default_frame_unwind_stop_reason(struct frame_info *this_frame, void **this_cache)
Definition: frame-unwind.c:180
frame_this_id_ftype * this_id
Definition: frame-unwind.h:151
const struct frame_data * unwind_data
Definition: frame-unwind.h:153
enum bfd_endian byte_order
Definition: gdbarch.c:128
struct value * trad_frame_get_register(struct trad_frame_cache *this_trad_cache, struct frame_info *this_frame, int regnum)
Definition: trad-frame.c:155
int(* validate)(const struct tramp_frame *self, struct frame_info *this_frame, CORE_ADDR *pc)
Definition: tramp-frame.h:76
struct gdbarch * get_frame_arch(struct frame_info *this_frame)
Definition: frame.c:2535