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424163ea DJ |
1 | /* Target description support for GDB. |
2 | ||
3 | Copyright (C) 2006 | |
4 | Free Software Foundation, Inc. | |
5 | ||
6 | Contributed by CodeSourcery. | |
7 | ||
8 | This file is part of GDB. | |
9 | ||
10 | This program is free software; you can redistribute it and/or modify | |
11 | it under the terms of the GNU General Public License as published by | |
12 | the Free Software Foundation; either version 2 of the License, or | |
13 | (at your option) any later version. | |
14 | ||
15 | This program is distributed in the hope that it will be useful, | |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU General Public License | |
21 | along with this program; if not, write to the Free Software | |
22 | Foundation, Inc., 51 Franklin Street, Fifth Floor, | |
23 | Boston, MA 02110-1301, USA. */ | |
24 | ||
25 | #include "defs.h" | |
26 | #include "arch-utils.h" | |
27 | #include "target.h" | |
28 | #include "target-descriptions.h" | |
29 | ||
30 | #include "gdb_assert.h" | |
31 | ||
32 | /* Types. */ | |
33 | ||
34 | struct target_desc | |
35 | { | |
36 | }; | |
37 | ||
38 | /* Global state. These variables are associated with the current | |
39 | target; if GDB adds support for multiple simultaneous targets, then | |
40 | these variables should become target-specific data. */ | |
41 | ||
42 | /* A flag indicating that a description has already been fetched from | |
43 | the current target, so it should not be queried again. */ | |
44 | ||
45 | static int target_desc_fetched; | |
46 | ||
47 | /* The description fetched from the current target, or NULL if the | |
48 | current target did not supply any description. Only valid when | |
49 | target_desc_fetched is set. Only the description initialization | |
50 | code should access this; normally, the description should be | |
51 | accessed through the gdbarch object. */ | |
52 | ||
53 | static const struct target_desc *current_target_desc; | |
54 | ||
55 | /* Fetch the current target's description, and switch the current | |
56 | architecture to one which incorporates that description. */ | |
57 | ||
58 | void | |
59 | target_find_description (void) | |
60 | { | |
61 | /* If we've already fetched a description from the target, don't do | |
62 | it again. This allows a target to fetch the description early, | |
63 | during its to_open or to_create_inferior, if it needs extra | |
64 | information about the target to initialize. */ | |
65 | if (target_desc_fetched) | |
66 | return; | |
67 | ||
68 | /* The current architecture should not have any target description | |
69 | specified. It should have been cleared, e.g. when we | |
70 | disconnected from the previous target. */ | |
71 | gdb_assert (gdbarch_target_desc (current_gdbarch) == NULL); | |
72 | ||
73 | current_target_desc = target_read_description (¤t_target); | |
74 | ||
75 | /* If a non-NULL description was returned, then update the current | |
76 | architecture. */ | |
77 | if (current_target_desc) | |
78 | { | |
79 | struct gdbarch_info info; | |
80 | ||
81 | gdbarch_info_init (&info); | |
82 | info.target_desc = current_target_desc; | |
83 | if (!gdbarch_update_p (info)) | |
84 | warning (_("Could not use target-supplied description")); | |
85 | } | |
86 | ||
87 | /* Now that we know this description is usable, record that we | |
88 | fetched it. */ | |
89 | target_desc_fetched = 1; | |
90 | } | |
91 | ||
92 | /* Discard any description fetched from the current target, and switch | |
93 | the current architecture to one with no target description. */ | |
94 | ||
95 | void | |
96 | target_clear_description (void) | |
97 | { | |
98 | struct gdbarch_info info; | |
99 | ||
100 | if (!target_desc_fetched) | |
101 | return; | |
102 | ||
103 | target_desc_fetched = 0; | |
104 | current_target_desc = NULL; | |
105 | ||
106 | gdbarch_info_init (&info); | |
107 | if (!gdbarch_update_p (info)) | |
108 | internal_error (__FILE__, __LINE__, | |
109 | _("Could not remove target-supplied description")); | |
110 | } | |
111 | ||
112 | /* Return the global current target description. This should only be | |
113 | used by gdbarch initialization code; most access should be through | |
114 | an existing gdbarch. */ | |
115 | ||
116 | const struct target_desc * | |
117 | target_current_description (void) | |
118 | { | |
119 | if (target_desc_fetched) | |
120 | return current_target_desc; | |
121 | ||
122 | return NULL; | |
123 | } | |
124 | ||
125 | /* Methods for constructing a target description. */ | |
126 | ||
127 | struct target_desc * | |
128 | allocate_target_description (void) | |
129 | { | |
130 | return XZALLOC (struct target_desc); | |
131 | } |