1/* User visible, per-frame registers, for GDB, the GNU debugger.
2
3   Copyright 2002, 2003, 2004 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 2 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, write to the Free Software
21   Foundation, Inc., 59 Temple Place - Suite 330,
22   Boston, MA 02111-1307, USA.  */
23
24#include "defs.h"
25#include "user-regs.h"
26#include "gdbtypes.h"
27#include "gdb_string.h"
28#include "gdb_assert.h"
29#include "frame.h"
30
31/* A table of user registers.
32
33   User registers have regnum's that live above of the range [0
34   .. NUM_REGS + NUM_PSEUDO_REGS) (which is controlled by the target).
35   The target should never see a user register's regnum value.
36
37   Always append, never delete.  By doing this, the relative regnum
38   (offset from NUM_REGS + NUM_PSEUDO_REGS) assigned to each user
39   register never changes.  */
40
41struct user_reg
42{
43  const char *name;
44  struct value *(*read) (struct frame_info * frame);
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, struct user_reg *reg)
63{
64  /* The caller is responsible for allocating memory needed to store
65     the register.  By doing this, the function can operate on a
66     register list stored in the common heap or a specific obstack.  */
67  gdb_assert (reg != NULL);
68  reg->name = name;
69  reg->read = read;
70  reg->next = NULL;
71  (*regs->last) = reg;
72  regs->last = &(*regs->last)->next;
73}
74
75/* An array of the builtin user registers.  */
76
77static struct gdb_user_regs builtin_user_regs = { NULL, &builtin_user_regs.first };
78
79void
80user_reg_add_builtin (const char *name, user_reg_read_ftype *read)
81{
82  append_user_reg (&builtin_user_regs, name, read,
83		   XMALLOC (struct user_reg));
84}
85
86/* Per-architecture user registers.  Start with the builtin user
87   registers and then, again, append.  */
88
89static struct gdbarch_data *user_regs_data;
90
91static void *
92user_regs_init (struct gdbarch *gdbarch)
93{
94  struct user_reg *reg;
95  struct gdb_user_regs *regs = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
96  regs->last = &regs->first;
97  for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
98    append_user_reg (regs, reg->name, reg->read,
99		     GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
100  return regs;
101}
102
103void
104user_reg_add (struct gdbarch *gdbarch, const char *name,
105		 user_reg_read_ftype *read)
106{
107  struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
108  if (regs == NULL)
109    {
110      /* ULGH, called during architecture initialization.  Patch
111         things up.  */
112      regs = user_regs_init (gdbarch);
113      set_gdbarch_data (gdbarch, user_regs_data, regs);
114    }
115  append_user_reg (regs, name, read,
116		   GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
117}
118
119int
120user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
121			     int len)
122{
123  /* Make life easy, set the len to something reasonable.  */
124  if (len < 0)
125    len = strlen (name);
126
127  /* Search register name space first - always let an architecture
128     specific register override the user registers.  */
129  {
130    int i;
131    int maxregs = (gdbarch_num_regs (gdbarch)
132		   + gdbarch_num_pseudo_regs (gdbarch));
133    for (i = 0; i < maxregs; i++)
134      {
135	const char *regname = gdbarch_register_name (gdbarch, i);
136	if (regname != NULL && len == strlen (regname)
137	    && strncmp (regname, name, len) == 0)
138	  {
139	    return i;
140	  }
141      }
142  }
143
144  /* Search the user name space.  */
145  {
146    struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
147    struct user_reg *reg;
148    int nr;
149    for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
150      {
151	if ((len < 0 && strcmp (reg->name, name))
152	    || (len == strlen (reg->name)
153		&& strncmp (reg->name, name, len) == 0))
154	  return NUM_REGS + NUM_PSEUDO_REGS + nr;
155      }
156  }
157
158  return -1;
159}
160
161static struct user_reg *
162usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
163{
164  struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
165  struct user_reg *reg;
166  for (reg = regs->first; reg != NULL; reg = reg->next)
167    {
168      if (usernum == 0)
169	return reg;
170      usernum--;
171    }
172  return NULL;
173}
174
175const char *
176user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
177{
178  int maxregs = (gdbarch_num_regs (gdbarch)
179		 + gdbarch_num_pseudo_regs (gdbarch));
180  if (regnum < 0)
181    return NULL;
182  else if (regnum < maxregs)
183    return gdbarch_register_name (gdbarch, regnum);
184  else
185    {
186      struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
187      if (reg == NULL)
188	return NULL;
189      else
190	return reg->name;
191    }
192}
193
194struct value *
195value_of_user_reg (int regnum, struct frame_info *frame)
196{
197  struct gdbarch *gdbarch = get_frame_arch (frame);
198  int maxregs = (gdbarch_num_regs (gdbarch)
199		 + gdbarch_num_pseudo_regs (gdbarch));
200  struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
201  gdb_assert (reg != NULL);
202  return reg->read (frame);
203}
204
205extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
206
207void
208_initialize_user_regs (void)
209{
210  user_regs_data = register_gdbarch_data (user_regs_init);
211}
212