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52a11cbf | 1 | /* Subroutines needed for unwinding stack frames for exception handling. */ |
83ffe9cd | 2 | /* Copyright (C) 1997-2023 Free Software Foundation, Inc. |
52a11cbf RH |
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 | |
748086b7 | 9 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 10 | version. |
52a11cbf | 11 | |
1322177d LB |
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
52a11cbf | 16 | |
748086b7 JJ |
17 | Under Section 7 of GPL version 3, you are granted additional |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | <http://www.gnu.org/licenses/>. */ | |
52a11cbf | 25 | |
7ce27103 ZW |
26 | #ifndef GCC_UNWIND_DW2_FDE_H |
27 | #define GCC_UNWIND_DW2_FDE_H | |
52a11cbf | 28 | |
7370bebd | 29 | #ifndef HIDE_EXPORTS |
3fc1f660 | 30 | #pragma GCC visibility push(default) |
7370bebd | 31 | #endif |
3fc1f660 | 32 | |
e1f9550a RH |
33 | struct fde_vector |
34 | { | |
a30794da | 35 | const void *orig_data; |
e1f9550a | 36 | size_t count; |
a30794da | 37 | const struct dwarf_fde *array[]; |
e1f9550a RH |
38 | }; |
39 | ||
52a11cbf | 40 | struct object |
e1f9550a RH |
41 | { |
42 | void *pc_begin; | |
43 | void *tbase; | |
44 | void *dbase; | |
45 | union { | |
a30794da | 46 | const struct dwarf_fde *single; |
e1f9550a RH |
47 | struct dwarf_fde **array; |
48 | struct fde_vector *sort; | |
49 | } u; | |
50 | ||
51 | union { | |
52 | struct { | |
53 | unsigned long sorted : 1; | |
54 | unsigned long from_array : 1; | |
55 | unsigned long mixed_encoding : 1; | |
56 | unsigned long encoding : 8; | |
57 | /* ??? Wish there was an easy way to detect a 64-bit host here; | |
3ef42a0c | 58 | we've got 32 bits left to play with... */ |
e1f9550a RH |
59 | unsigned long count : 21; |
60 | } b; | |
61 | size_t i; | |
62 | } s; | |
63 | ||
3cfe49da GK |
64 | #ifdef DWARF2_OBJECT_END_PTR_EXTENSION |
65 | char *fde_end; | |
66 | #endif | |
67 | ||
e1f9550a RH |
68 | struct object *next; |
69 | }; | |
70 | ||
71 | /* This is the original definition of struct object. While the struct | |
72 | itself was opaque to users, they did know how large it was, and | |
73 | allocate one statically in crtbegin for each DSO. Keep this around | |
74 | so that we're aware of the static size limitations for the new struct. */ | |
75 | struct old_object | |
52a11cbf RH |
76 | { |
77 | void *pc_begin; | |
78 | void *pc_end; | |
79 | struct dwarf_fde *fde_begin; | |
80 | struct dwarf_fde **fde_array; | |
81 | size_t count; | |
e1f9550a | 82 | struct old_object *next; |
52a11cbf RH |
83 | }; |
84 | ||
85 | struct dwarf_eh_bases | |
86 | { | |
87 | void *tbase; | |
88 | void *dbase; | |
89 | void *func; | |
90 | }; | |
91 | ||
92 | ||
a30794da | 93 | extern void __register_frame_info_bases (const void *, struct object *, |
e1f9550a | 94 | void *, void *); |
a30794da | 95 | extern void __register_frame_info (const void *, struct object *); |
52a11cbf | 96 | extern void __register_frame (void *); |
e1f9550a RH |
97 | extern void __register_frame_info_table_bases (void *, struct object *, |
98 | void *, void *); | |
52a11cbf RH |
99 | extern void __register_frame_info_table (void *, struct object *); |
100 | extern void __register_frame_table (void *); | |
a30794da AJ |
101 | extern void *__deregister_frame_info (const void *); |
102 | extern void *__deregister_frame_info_bases (const void *); | |
52a11cbf RH |
103 | extern void __deregister_frame (void *); |
104 | ||
105 | \f | |
106 | typedef int sword __attribute__ ((mode (SI))); | |
107 | typedef unsigned int uword __attribute__ ((mode (SI))); | |
108 | typedef unsigned int uaddr __attribute__ ((mode (pointer))); | |
109 | typedef int saddr __attribute__ ((mode (pointer))); | |
110 | typedef unsigned char ubyte; | |
111 | ||
112 | /* Terminology: | |
113 | CIE - Common Information Element | |
114 | FDE - Frame Descriptor Element | |
115 | ||
116 | There is one per function, and it describes where the function code | |
117 | is located, and what the register lifetimes and stack layout are | |
118 | within the function. | |
119 | ||
eaec9b3d | 120 | The data structures are defined in the DWARF specification, although |
52a11cbf RH |
121 | not in a very readable way (see LITERATURE). |
122 | ||
123 | Every time an exception is thrown, the code needs to locate the FDE | |
124 | for the current function, and starts to look for exception regions | |
125 | from that FDE. This works in a two-level search: | |
126 | a) in a linear search, find the shared image (i.e. DLL) containing | |
127 | the PC | |
128 | b) using the FDE table for that shared object, locate the FDE using | |
41077ce4 | 129 | binary search (which requires the sorting). */ |
52a11cbf RH |
130 | |
131 | /* The first few fields of a CIE. The CIE_id field is 0 for a CIE, | |
132 | to distinguish it from a valid FDE. FDEs are aligned to an addressing | |
133 | unit boundary, but the fields within are unaligned. */ | |
134 | struct dwarf_cie | |
135 | { | |
136 | uword length; | |
137 | sword CIE_id; | |
138 | ubyte version; | |
139 | unsigned char augmentation[]; | |
140 | } __attribute__ ((packed, aligned (__alignof__ (void *)))); | |
141 | ||
142 | /* The first few fields of an FDE. */ | |
143 | struct dwarf_fde | |
144 | { | |
145 | uword length; | |
146 | sword CIE_delta; | |
e1f9550a | 147 | unsigned char pc_begin[]; |
52a11cbf RH |
148 | } __attribute__ ((packed, aligned (__alignof__ (void *)))); |
149 | ||
150 | typedef struct dwarf_fde fde; | |
151 | ||
152 | /* Locate the CIE for a given FDE. */ | |
153 | ||
a30794da AJ |
154 | static inline const struct dwarf_cie * |
155 | get_cie (const struct dwarf_fde *f) | |
52a11cbf | 156 | { |
5f754896 | 157 | return (const void *)&f->CIE_delta - f->CIE_delta; |
52a11cbf RH |
158 | } |
159 | ||
a30794da AJ |
160 | static inline const fde * |
161 | next_fde (const fde *f) | |
52a11cbf | 162 | { |
5f754896 | 163 | return (const fde *) ((const char *) f + f->length + sizeof (f->length)); |
52a11cbf RH |
164 | } |
165 | ||
a30794da | 166 | extern const fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *); |
3cfe49da GK |
167 | |
168 | static inline int | |
6e80a1d1 | 169 | last_fde (const struct object *obj __attribute__ ((__unused__)), const fde *f) |
3cfe49da GK |
170 | { |
171 | #ifdef DWARF2_OBJECT_END_PTR_EXTENSION | |
324820f1 | 172 | return f == (const fde *) obj->fde_end || f->length == 0; |
3cfe49da GK |
173 | #else |
174 | return f->length == 0; | |
175 | #endif | |
176 | } | |
7ce27103 | 177 | |
7370bebd | 178 | #ifndef HIDE_EXPORTS |
3fc1f660 | 179 | #pragma GCC visibility pop |
7370bebd | 180 | #endif |
3fc1f660 | 181 | |
7ce27103 | 182 | #endif /* unwind-dw2-fde.h */ |