1/* User visible, per-frame registers, for GDB, the GNU debugger.
2
3   Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
4
5   Contributed by Red Hat.
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 3 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, see <http://www.gnu.org/licenses/>.  */
21
22#include "defs.h"
23#include "user-regs.h"
24#include "gdbtypes.h"
25#include "gdb_string.h"
26#include "gdb_assert.h"
27#include "frame.h"
28
29/* A table of user registers.
30
31   User registers have regnum's that live above of the range [0
32   .. gdbarch_num_regs + gdbarch_num_pseudo_regs)
33   (which is controlled by the target).
34   The target should never see a user register's regnum value.
35
36   Always append, never delete.  By doing this, the relative regnum
37   (offset from gdbarch_num_regs + gdbarch_num_pseudo_regs)
38    assigned to each user  register never changes.  */
39
40struct user_reg
41{
42  const char *name;
43  struct value *(*read) (struct frame_info * frame, const void *baton);
44  const void *baton;
45  struct user_reg *next;
46};
47
48/* This structure is named gdb_user_regs instead of user_regs to avoid
49   conflicts with any "struct user_regs" in system headers.  For instance,
50   on ARM GNU/Linux native builds, nm-linux.h includes <signal.h> includes
51   <sys/ucontext.h> includes <sys/procfs.h> includes <sys/user.h>, which
52   declares "struct user_regs".  */
53
54struct gdb_user_regs
55{
56  struct user_reg *first;
57  struct user_reg **last;
58};
59
60static void
61append_user_reg (struct gdb_user_regs *regs, const char *name,
62		 user_reg_read_ftype *read, const void *baton,
63		 struct user_reg *reg)
64{
65  /* The caller is responsible for allocating memory needed to store
66     the register.  By doing this, the function can operate on a
67     register list stored in the common heap or a specific obstack.  */
68  gdb_assert (reg != NULL);
69  reg->name = name;
70  reg->read = read;
71  reg->baton = baton;
72  reg->next = NULL;
73  (*regs->last) = reg;
74  regs->last = &(*regs->last)->next;
75}
76
77/* An array of the builtin user registers.  */
78
79static struct gdb_user_regs builtin_user_regs = { NULL, &builtin_user_regs.first };
80
81void
82user_reg_add_builtin (const char *name, user_reg_read_ftype *read,
83		      const void *baton)
84{
85  append_user_reg (&builtin_user_regs, name, read, baton,
86		   XMALLOC (struct user_reg));
87}
88
89/* Per-architecture user registers.  Start with the builtin user
90   registers and then, again, append.  */
91
92static struct gdbarch_data *user_regs_data;
93
94static void *
95user_regs_init (struct gdbarch *gdbarch)
96{
97  struct user_reg *reg;
98  struct gdb_user_regs *regs = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
99  regs->last = &regs->first;
100  for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
101    append_user_reg (regs, reg->name, reg->read, reg->baton,
102		     GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
103  return regs;
104}
105
106void
107user_reg_add (struct gdbarch *gdbarch, const char *name,
108	      user_reg_read_ftype *read, const void *baton)
109{
110  struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
111  if (regs == NULL)
112    {
113      /* ULGH, called during architecture initialization.  Patch
114         things up.  */
115      regs = user_regs_init (gdbarch);
116      deprecated_set_gdbarch_data (gdbarch, user_regs_data, regs);
117    }
118  append_user_reg (regs, name, read, baton,
119		   GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
120}
121
122int
123user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
124			     int len)
125{
126  /* Make life easy, set the len to something reasonable.  */
127  if (len < 0)
128    len = strlen (name);
129
130  /* Search register name space first - always let an architecture
131     specific register override the user registers.  */
132  {
133    int i;
134    int maxregs = (gdbarch_num_regs (gdbarch)
135		   + gdbarch_num_pseudo_regs (gdbarch));
136    for (i = 0; i < maxregs; i++)
137      {
138	const char *regname = gdbarch_register_name (gdbarch, i);
139	if (regname != NULL && len == strlen (regname)
140	    && strncmp (regname, name, len) == 0)
141	  {
142	    return i;
143	  }
144      }
145  }
146
147  /* Search the user name space.  */
148  {
149    struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
150    struct user_reg *reg;
151    int nr;
152    for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
153      {
154	if ((len < 0 && strcmp (reg->name, name))
155	    || (len == strlen (reg->name)
156		&& strncmp (reg->name, name, len) == 0))
157	  return gdbarch_num_regs (current_gdbarch)
158		 + gdbarch_num_pseudo_regs (current_gdbarch) + nr;
159      }
160  }
161
162  return -1;
163}
164
165static struct user_reg *
166usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
167{
168  struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
169  struct user_reg *reg;
170  for (reg = regs->first; reg != NULL; reg = reg->next)
171    {
172      if (usernum == 0)
173	return reg;
174      usernum--;
175    }
176  return NULL;
177}
178
179const char *
180user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
181{
182  int maxregs = (gdbarch_num_regs (gdbarch)
183		 + gdbarch_num_pseudo_regs (gdbarch));
184  if (regnum < 0)
185    return NULL;
186  else if (regnum < maxregs)
187    return gdbarch_register_name (gdbarch, regnum);
188  else
189    {
190      struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
191      if (reg == NULL)
192	return NULL;
193      else
194	return reg->name;
195    }
196}
197
198struct value *
199value_of_user_reg (int regnum, struct frame_info *frame)
200{
201  struct gdbarch *gdbarch = get_frame_arch (frame);
202  int maxregs = (gdbarch_num_regs (gdbarch)
203		 + gdbarch_num_pseudo_regs (gdbarch));
204  struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
205  gdb_assert (reg != NULL);
206  return reg->read (frame, reg->baton);
207}
208
209extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
210
211void
212_initialize_user_regs (void)
213{
214  user_regs_data = gdbarch_data_register_post_init (user_regs_init);
215}
216