gdb/target-descriptions.c

   1 /* Target description support for GDB.
   2
   3    Copyright (C) 2006, 2007 Free Software Foundation, Inc.
   4
   5    Contributed by CodeSourcery.
   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., 51 Franklin Street, Fifth Floor,
  22    Boston, MA 02110-1301, USA.  */
  23
  24 #include "defs.h"
  25 #include "arch-utils.h"
  26 #include "target.h"
  27 #include "target-descriptions.h"
  28 #include "vec.h"
  29
  30 #include "gdb_assert.h"
  31
  32 /* Types.  */
  33
  34 typedef struct property
  35 {
  36   const char *key;
  37   const char *value;
  38 } property_s;
  39 DEF_VEC_O(property_s);
  40
  41 struct target_desc
  42 {
  43   /* Any architecture-specific properties specified by the target.  */
  44   VEC(property_s) *properties;
  45 };
  46
  47 /* Global state.  These variables are associated with the current
  48    target; if GDB adds support for multiple simultaneous targets, then
  49    these variables should become target-specific data.  */
  50
  51 /* A flag indicating that a description has already been fetched from
  52    the current target, so it should not be queried again.  */
  53
  54 static int target_desc_fetched;
  55
  56 /* The description fetched from the current target, or NULL if the
  57    current target did not supply any description.  Only valid when
  58    target_desc_fetched is set.  Only the description initialization
  59    code should access this; normally, the description should be
  60    accessed through the gdbarch object.  */
  61
  62 static const struct target_desc *current_target_desc;
  63
  64 /* Fetch the current target's description, and switch the current
  65    architecture to one which incorporates that description.  */
  66
  67 void
  68 target_find_description (void)
  69 {
  70   /* If we've already fetched a description from the target, don't do
  71      it again.  This allows a target to fetch the description early,
  72      during its to_open or to_create_inferior, if it needs extra
  73      information about the target to initialize.  */
  74   if (target_desc_fetched)
  75     return;
  76
  77   /* The current architecture should not have any target description
  78      specified.  It should have been cleared, e.g. when we
  79      disconnected from the previous target.  */
  80   gdb_assert (gdbarch_target_desc (current_gdbarch) == NULL);
  81
  82   current_target_desc = target_read_description (&current_target);
  83
  84   /* If a non-NULL description was returned, then update the current
  85      architecture.  */
  86   if (current_target_desc)
  87     {
  88       struct gdbarch_info info;
  89
  90       gdbarch_info_init (&info);
  91       info.target_desc = current_target_desc;
  92       if (!gdbarch_update_p (info))
  93         warning (_("Could not use target-supplied description"));
  94     }
  95
  96   /* Now that we know this description is usable, record that we
  97      fetched it.  */
  98   target_desc_fetched = 1;
  99 }
 100
 101 /* Discard any description fetched from the current target, and switch
 102    the current architecture to one with no target description.  */
 103
 104 void
 105 target_clear_description (void)
 106 {
 107   struct gdbarch_info info;
 108
 109   if (!target_desc_fetched)
 110     return;
 111
 112   target_desc_fetched = 0;
 113   current_target_desc = NULL;
 114
 115   gdbarch_info_init (&info);
 116   if (!gdbarch_update_p (info))
 117     internal_error (__FILE__, __LINE__,
 118                     _("Could not remove target-supplied description"));
 119 }
 120
 121 /* Return the global current target description.  This should only be
 122    used by gdbarch initialization code; most access should be through
 123    an existing gdbarch.  */
 124
 125 const struct target_desc *
 126 target_current_description (void)
 127 {
 128   if (target_desc_fetched)
 129     return current_target_desc;
 130
 131   return NULL;
 132 }
 133
 134 /* Return the string value of a property named KEY, or NULL if the
 135    property was not specified.  */
 136
 137 const char *
 138 tdesc_property (const struct target_desc *target_desc, const char *key)
 139 {
 140   struct property *prop;
 141   int ix;
 142
 143   for (ix = 0; VEC_iterate (property_s, target_desc->properties, ix, prop);
 144        ix++)
 145     if (strcmp (prop->key, key) == 0)
 146       return prop->value;
 147
 148   return NULL;
 149 }
 150
 151 /* Methods for constructing a target description.  */
 152
 153 struct target_desc *
 154 allocate_target_description (void)
 155 {
 156   return XZALLOC (struct target_desc);
 157 }
 158
 159 void
 160 set_tdesc_property (struct target_desc *target_desc,
 161                     const char *key, const char *value)
 162 {
 163   struct property *prop, new_prop;
 164   int ix;
 165
 166   gdb_assert (key != NULL && value != NULL);
 167
 168   for (ix = 0; VEC_iterate (property_s, target_desc->properties, ix, prop);
 169        ix++)
 170     if (strcmp (prop->key, key) == 0)
 171       internal_error (__FILE__, __LINE__,
 172                       _("Attempted to add duplicate property \"%s\""), key);
 173
 174   new_prop.key = key;
 175   new_prop.value = value;
 176   VEC_safe_push (property_s, target_desc->properties, &new_prop);
 177 }