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1 | /* Subroutines needed for unwinding stack frames for exception handling. */ |
2 | /* Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. | |
3 | Contributed by Jason Merrill <jason@cygnus.com>. | |
4 | ||
1322177d | 5 | This file is part of GCC. |
52a11cbf | 6 | |
1322177d LB |
7 | GCC is free software; you can redistribute it and/or modify it under |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
52a11cbf RH |
11 | |
12 | In addition to the permissions in the GNU General Public License, the | |
13 | Free Software Foundation gives you unlimited permission to link the | |
14 | compiled version of this file into combinations with other programs, | |
15 | and to distribute those combinations without any restriction coming | |
16 | from the use of this file. (The General Public License restrictions | |
17 | do apply in other respects; for example, they cover modification of | |
18 | the file, and distribution when not linked into a combine | |
19 | executable.) | |
20 | ||
1322177d LB |
21 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
22 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
23 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
24 | for more details. | |
52a11cbf RH |
25 | |
26 | You should have received a copy of the GNU General Public License | |
1322177d LB |
27 | along with GCC; see the file COPYING. If not, write to the Free |
28 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
29 | 02111-1307, USA. */ | |
52a11cbf RH |
30 | |
31 | ||
e1f9550a RH |
32 | struct fde_vector |
33 | { | |
34 | void *orig_data; | |
35 | size_t count; | |
36 | struct dwarf_fde *array[]; | |
37 | }; | |
38 | ||
52a11cbf | 39 | struct object |
e1f9550a RH |
40 | { |
41 | void *pc_begin; | |
42 | void *tbase; | |
43 | void *dbase; | |
44 | union { | |
45 | struct dwarf_fde *single; | |
46 | struct dwarf_fde **array; | |
47 | struct fde_vector *sort; | |
48 | } u; | |
49 | ||
50 | union { | |
51 | struct { | |
52 | unsigned long sorted : 1; | |
53 | unsigned long from_array : 1; | |
54 | unsigned long mixed_encoding : 1; | |
55 | unsigned long encoding : 8; | |
56 | /* ??? Wish there was an easy way to detect a 64-bit host here; | |
57 | we've got 32 bits left to play with... */ | |
58 | unsigned long count : 21; | |
59 | } b; | |
60 | size_t i; | |
61 | } s; | |
62 | ||
63 | struct object *next; | |
64 | }; | |
65 | ||
66 | /* This is the original definition of struct object. While the struct | |
67 | itself was opaque to users, they did know how large it was, and | |
68 | allocate one statically in crtbegin for each DSO. Keep this around | |
69 | so that we're aware of the static size limitations for the new struct. */ | |
70 | struct old_object | |
52a11cbf RH |
71 | { |
72 | void *pc_begin; | |
73 | void *pc_end; | |
74 | struct dwarf_fde *fde_begin; | |
75 | struct dwarf_fde **fde_array; | |
76 | size_t count; | |
e1f9550a | 77 | struct old_object *next; |
52a11cbf RH |
78 | }; |
79 | ||
80 | struct dwarf_eh_bases | |
81 | { | |
82 | void *tbase; | |
83 | void *dbase; | |
84 | void *func; | |
85 | }; | |
86 | ||
87 | ||
e1f9550a RH |
88 | extern void __register_frame_info_bases (void *, struct object *, |
89 | void *, void *); | |
52a11cbf RH |
90 | extern void __register_frame_info (void *, struct object *); |
91 | extern void __register_frame (void *); | |
e1f9550a RH |
92 | extern void __register_frame_info_table_bases (void *, struct object *, |
93 | void *, void *); | |
52a11cbf RH |
94 | extern void __register_frame_info_table (void *, struct object *); |
95 | extern void __register_frame_table (void *); | |
96 | extern void *__deregister_frame_info (void *); | |
101fa48c | 97 | extern void *__deregister_frame_info_bases (void *); |
52a11cbf RH |
98 | extern void __deregister_frame (void *); |
99 | ||
100 | \f | |
101 | typedef int sword __attribute__ ((mode (SI))); | |
102 | typedef unsigned int uword __attribute__ ((mode (SI))); | |
103 | typedef unsigned int uaddr __attribute__ ((mode (pointer))); | |
104 | typedef int saddr __attribute__ ((mode (pointer))); | |
105 | typedef unsigned char ubyte; | |
106 | ||
107 | /* Terminology: | |
108 | CIE - Common Information Element | |
109 | FDE - Frame Descriptor Element | |
110 | ||
111 | There is one per function, and it describes where the function code | |
112 | is located, and what the register lifetimes and stack layout are | |
113 | within the function. | |
114 | ||
eaec9b3d | 115 | The data structures are defined in the DWARF specification, although |
52a11cbf RH |
116 | not in a very readable way (see LITERATURE). |
117 | ||
118 | Every time an exception is thrown, the code needs to locate the FDE | |
119 | for the current function, and starts to look for exception regions | |
120 | from that FDE. This works in a two-level search: | |
121 | a) in a linear search, find the shared image (i.e. DLL) containing | |
122 | the PC | |
123 | b) using the FDE table for that shared object, locate the FDE using | |
124 | binary search (which requires the sorting). */ | |
125 | ||
126 | /* The first few fields of a CIE. The CIE_id field is 0 for a CIE, | |
127 | to distinguish it from a valid FDE. FDEs are aligned to an addressing | |
128 | unit boundary, but the fields within are unaligned. */ | |
129 | struct dwarf_cie | |
130 | { | |
131 | uword length; | |
132 | sword CIE_id; | |
133 | ubyte version; | |
134 | unsigned char augmentation[]; | |
135 | } __attribute__ ((packed, aligned (__alignof__ (void *)))); | |
136 | ||
137 | /* The first few fields of an FDE. */ | |
138 | struct dwarf_fde | |
139 | { | |
140 | uword length; | |
141 | sword CIE_delta; | |
e1f9550a | 142 | unsigned char pc_begin[]; |
52a11cbf RH |
143 | } __attribute__ ((packed, aligned (__alignof__ (void *)))); |
144 | ||
145 | typedef struct dwarf_fde fde; | |
146 | ||
147 | /* Locate the CIE for a given FDE. */ | |
148 | ||
149 | static inline struct dwarf_cie * | |
150 | get_cie (struct dwarf_fde *f) | |
151 | { | |
152 | return (void *)&f->CIE_delta - f->CIE_delta; | |
153 | } | |
154 | ||
155 | static inline fde * | |
156 | next_fde (fde *f) | |
157 | { | |
158 | return (fde *)((char *)f + f->length + sizeof (f->length)); | |
159 | } | |
160 | ||
161 | extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *); |