aboutsummaryrefslogtreecommitdiff
path: root/gdb/trad-frame.c
blob: 755d3b963b14d0a566a00fb708a61165ba5b0ded (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/* Traditional frame unwind support, for GDB the GNU Debugger.

   Copyright (C) 2003-2023 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "frame.h"
#include "trad-frame.h"
#include "regcache.h"
#include "frame-unwind.h"
#include "target.h"
#include "value.h"
#include "gdbarch.h"
#include "gdbsupport/traits.h"

struct trad_frame_cache
{
  frame_info_ptr this_frame;
  CORE_ADDR this_base;
  trad_frame_saved_reg *prev_regs;
  struct frame_id this_id;
};

struct trad_frame_cache *
trad_frame_cache_zalloc (frame_info_ptr this_frame)
{
  struct trad_frame_cache *this_trad_cache;

  this_trad_cache = FRAME_OBSTACK_ZALLOC (struct trad_frame_cache);
  this_trad_cache->prev_regs = trad_frame_alloc_saved_regs (this_frame);
  this_trad_cache->this_frame = this_frame;
  return this_trad_cache;
}

/* See trad-frame.h.  */

void
trad_frame_reset_saved_regs (struct gdbarch *gdbarch,
			     trad_frame_saved_reg *regs)
{
  int numregs = gdbarch_num_cooked_regs (gdbarch);

  for (int regnum = 0; regnum < numregs; regnum++)
    regs[regnum].set_realreg (regnum);
}

trad_frame_saved_reg *
trad_frame_alloc_saved_regs (struct gdbarch *gdbarch)
{
#ifdef HAVE_IS_TRIVIALLY_CONSTRUCTIBLE
  static_assert (std::is_trivially_constructible<trad_frame_saved_reg>::value);
#endif

  int numregs = gdbarch_num_cooked_regs (gdbarch);
  trad_frame_saved_reg *this_saved_regs
    = FRAME_OBSTACK_CALLOC (numregs, trad_frame_saved_reg);

  /* For backwards compatibility, initialize all the register values to
     REALREG, with register 0 stored in 0, register 1 stored in 1 and so
     on.  */
  trad_frame_reset_saved_regs (gdbarch, this_saved_regs);

  return this_saved_regs;
}

/* A traditional frame is unwound by analysing the function prologue
   and using the information gathered to track registers.  For
   non-optimized frames, the technique is reliable (just need to check
   for all potential instruction sequences).  */

trad_frame_saved_reg *
trad_frame_alloc_saved_regs (frame_info_ptr this_frame)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);

  return trad_frame_alloc_saved_regs (gdbarch);
}

void
trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
			  int regnum, LONGEST val)
{
  /* External interface for users of trad_frame_cache
     (who cannot access the prev_regs object directly).  */
  this_trad_cache->prev_regs[regnum].set_value (val);
}

void
trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
			    int regnum, int realreg)
{
  this_trad_cache->prev_regs[regnum].set_realreg (realreg);
}

void
trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
			 int regnum, CORE_ADDR addr)
{
  this_trad_cache->prev_regs[regnum].set_addr (addr);
}

void
trad_frame_set_reg_regmap (struct trad_frame_cache *this_trad_cache,
			   const struct regcache_map_entry *regmap,
			   CORE_ADDR addr, size_t size)
{
  struct gdbarch *gdbarch = get_frame_arch (this_trad_cache->this_frame);
  int offs = 0, count;

  for (; (count = regmap->count) != 0; regmap++)
    {
      int regno = regmap->regno;
      int slot_size = regmap->size;

      if (slot_size == 0 && regno != REGCACHE_MAP_SKIP)
	slot_size = register_size (gdbarch, regno);

      if (offs + slot_size > size)
	break;

      if (regno == REGCACHE_MAP_SKIP)
	offs += count * slot_size;
      else
	for (; count--; regno++, offs += slot_size)
	  {
	    /* Mimic the semantics of regcache::transfer_regset if a
	       register slot's size does not match the size of a
	       register.

	       If a register slot is larger than a register, assume
	       the register's value is stored in the first N bytes of
	       the slot and ignore the remaining bytes.

	       If the register slot is smaller than the register,
	       assume that the slot contains the low N bytes of the
	       register's value.  Since trad_frame assumes that
	       registers stored by address are sized according to the
	       register, read the low N bytes and zero-extend them to
	       generate a register value.  */
	    if (slot_size >= register_size (gdbarch, regno))
	      trad_frame_set_reg_addr (this_trad_cache, regno, addr + offs);
	    else
	      {
		enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
		gdb_byte buf[slot_size];

		if (target_read_memory (addr + offs, buf, sizeof buf) == 0)
		  {
		    LONGEST val
		      = extract_unsigned_integer (buf, sizeof buf, byte_order);
		    trad_frame_set_reg_value (this_trad_cache, regno, val);
		  }
	      }
	  }
    }
}

/* See trad-frame.h.  */

void
trad_frame_set_reg_value_bytes (struct trad_frame_cache *this_trad_cache,
				int regnum,
				gdb::array_view<const gdb_byte> bytes)
{
  /* External interface for users of trad_frame_cache
     (who cannot access the prev_regs object directly).  */
  this_trad_cache->prev_regs[regnum].set_value_bytes (bytes);
}



struct value *
trad_frame_get_prev_register (frame_info_ptr this_frame,
			      trad_frame_saved_reg this_saved_regs[],
			      int regnum)
{
  if (this_saved_regs[regnum].is_addr ())
    /* The register was saved in memory.  */
    return frame_unwind_got_memory (this_frame, regnum,
				    this_saved_regs[regnum].addr ());
  else if (this_saved_regs[regnum].is_realreg ())
    return frame_unwind_got_register (this_frame, regnum,
				      this_saved_regs[regnum].realreg ());
  else if (this_saved_regs[regnum].is_value ())
    /* The register's value is available.  */
    return frame_unwind_got_constant (this_frame, regnum,
				      this_saved_regs[regnum].value ());
  else if (this_saved_regs[regnum].is_value_bytes ())
    /* The register's value is available as a sequence of bytes.  */
    return frame_unwind_got_bytes (this_frame, regnum,
				   this_saved_regs[regnum].value_bytes ());
  else
    return frame_unwind_got_optimized (this_frame, regnum);
}

struct value *
trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
			 frame_info_ptr this_frame,
			 int regnum)
{
  return trad_frame_get_prev_register (this_frame, this_trad_cache->prev_regs,
				       regnum);
}

void
trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
		   struct frame_id this_id)
{
  this_trad_cache->this_id = this_id;
}

void
trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
		   struct frame_id *this_id)
{
  (*this_id) = this_trad_cache->this_id;
}

void
trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
			  CORE_ADDR this_base)
{
  this_trad_cache->this_base = this_base;
}

CORE_ADDR
trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
{
  return this_trad_cache->this_base;
}