aboutsummaryrefslogtreecommitdiff
path: root/gdb/user-regs.c
blob: e9a47be767dcedcf92c3a6d911989b14d1005695 (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
/* User visible, per-frame registers, for GDB, the GNU debugger.

   Copyright (C) 2002-2022 Free Software Foundation, Inc.

   Contributed by Red Hat.

   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 "user-regs.h"
#include "gdbtypes.h"
#include "frame.h"
#include "arch-utils.h"
#include "command.h"
#include "cli/cli-cmds.h"

/* A table of user registers.

   User registers have regnum's that live above of the range [0
   .. gdbarch_num_regs + gdbarch_num_pseudo_regs)
   (which is controlled by the target).
   The target should never see a user register's regnum value.

   Always append, never delete.  By doing this, the relative regnum
   (offset from gdbarch_num_regs + gdbarch_num_pseudo_regs)
    assigned to each user  register never changes.  */

struct user_reg
{
  const char *name;
  /* Avoid the "read" symbol name as it conflicts with a preprocessor symbol
     in the NetBSD header for Stack Smashing Protection, that wraps the read(2)
     syscall.  */
  struct value *(*xread) (struct frame_info * frame, const void *baton);
  const void *baton;
  struct user_reg *next;
};

/* This structure is named gdb_user_regs instead of user_regs to avoid
   conflicts with any "struct user_regs" in system headers.  For instance,
   on ARM GNU/Linux native builds, nm-linux.h includes <signal.h> includes
   <sys/ucontext.h> includes <sys/procfs.h> includes <sys/user.h>, which
   declares "struct user_regs".  */

struct gdb_user_regs
{
  struct user_reg *first;
  struct user_reg **last;
};

static void
append_user_reg (struct gdb_user_regs *regs, const char *name,
		 user_reg_read_ftype *xread, const void *baton,
		 struct user_reg *reg)
{
  /* The caller is responsible for allocating memory needed to store
     the register.  By doing this, the function can operate on a
     register list stored in the common heap or a specific obstack.  */
  gdb_assert (reg != NULL);
  reg->name = name;
  reg->xread = xread;
  reg->baton = baton;
  reg->next = NULL;
  (*regs->last) = reg;
  regs->last = &(*regs->last)->next;
}

/* An array of the builtin user registers.  */

static struct gdb_user_regs builtin_user_regs = {
  NULL, &builtin_user_regs.first
};

void
user_reg_add_builtin (const char *name, user_reg_read_ftype *xread,
		      const void *baton)
{
  append_user_reg (&builtin_user_regs, name, xread, baton,
		   XNEW (struct user_reg));
}

/* Per-architecture user registers.  Start with the builtin user
   registers and then, again, append.  */

static struct gdbarch_data *user_regs_data;

static void *
user_regs_init (struct obstack *obstack)
{
  struct user_reg *reg;
  struct gdb_user_regs *regs = OBSTACK_ZALLOC (obstack, struct gdb_user_regs);

  regs->last = &regs->first;
  for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
    append_user_reg (regs, reg->name, reg->xread, reg->baton,
		     OBSTACK_ZALLOC (obstack, struct user_reg));
  return regs;
}

void
user_reg_add (struct gdbarch *gdbarch, const char *name,
	      user_reg_read_ftype *xread, const void *baton)
{
  struct gdb_user_regs *regs
    = (struct gdb_user_regs *) gdbarch_data (gdbarch, user_regs_data);
  gdb_assert (regs != NULL);
  append_user_reg (regs, name, xread, baton,
		   GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
}

int
user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
			     int len)
{
  /* Make life easy, set the len to something reasonable.  */
  if (len < 0)
    len = strlen (name);

  /* Search register name space first - always let an architecture
     specific register override the user registers.  */
  {
    int i;
    int maxregs = gdbarch_num_cooked_regs (gdbarch);

    for (i = 0; i < maxregs; i++)
      {
	const char *regname = gdbarch_register_name (gdbarch, i);

	if (regname != NULL && len == strlen (regname)
	    && strncmp (regname, name, len) == 0)
	  {
	    return i;
	  }
      }
  }

  /* Search the user name space.  */
  {
    struct gdb_user_regs *regs
      = (struct gdb_user_regs *) gdbarch_data (gdbarch, user_regs_data);
    struct user_reg *reg;
    int nr;

    for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
      {
	if ((len < 0 && strcmp (reg->name, name))
	    || (len == strlen (reg->name)
		&& strncmp (reg->name, name, len) == 0))
	  return gdbarch_num_cooked_regs (gdbarch) + nr;
      }
  }

  return -1;
}

static struct user_reg *
usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
{
  struct gdb_user_regs *regs
    = (struct gdb_user_regs *) gdbarch_data (gdbarch, user_regs_data);
  struct user_reg *reg;

  for (reg = regs->first; reg != NULL; reg = reg->next)
    {
      if (usernum == 0)
	return reg;
      usernum--;
    }
  return NULL;
}

const char *
user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
{
  int maxregs = gdbarch_num_cooked_regs (gdbarch);

  if (regnum < 0)
    return NULL;
  else if (regnum < maxregs)
    return gdbarch_register_name (gdbarch, regnum);
  else
    {
      struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
      if (reg == NULL)
	return NULL;
      else
	return reg->name;
    }
}

struct value *
value_of_user_reg (int regnum, struct frame_info *frame)
{
  struct gdbarch *gdbarch = get_frame_arch (frame);
  int maxregs = gdbarch_num_cooked_regs (gdbarch);
  struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);

  gdb_assert (reg != NULL);
  return reg->xread (frame, reg->baton);
}

static void
maintenance_print_user_registers (const char *args, int from_tty)
{
  struct gdbarch *gdbarch = get_current_arch ();
  struct gdb_user_regs *regs;
  struct user_reg *reg;
  int regnum;

  regs = (struct gdb_user_regs *) gdbarch_data (gdbarch, user_regs_data);
  regnum = gdbarch_num_cooked_regs (gdbarch);

  printf_filtered (" %-11s %3s\n", "Name", "Nr");
  for (reg = regs->first; reg != NULL; reg = reg->next, ++regnum)
    printf_filtered (" %-11s %3d\n", reg->name, regnum);
}

void _initialize_user_regs ();
void
_initialize_user_regs ()
{
  user_regs_data = gdbarch_data_register_pre_init (user_regs_init);

  add_cmd ("user-registers", class_maintenance,
	   maintenance_print_user_registers,
	   _("List the names of the current user registers."),
	   &maintenanceprintlist);
}