1/* Subroutines needed for unwinding stack frames for exception handling.  */
2/* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004
3   Free Software Foundation, Inc.
4   Contributed by Jason Merrill <jason@cygnus.com>.
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 2, or (at your option) any later
11version.
12
13In addition to the permissions in the GNU General Public License, the
14Free Software Foundation gives you unlimited permission to link the
15compiled version of this file into combinations with other programs,
16and to distribute those combinations without any restriction coming
17from the use of this file.  (The General Public License restrictions
18do apply in other respects; for example, they cover modification of
19the file, and distribution when not linked into a combine
20executable.)
21
22GCC is distributed in the hope that it will be useful, but WITHOUT ANY
23WARRANTY; without even the implied warranty of MERCHANTABILITY or
24FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
25for more details.
26
27You should have received a copy of the GNU General Public License
28along with GCC; see the file COPYING.  If not, write to the Free
29Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
3002110-1301, USA.  */
31
32#ifndef GCC_UNWIND_DW2_FDE_H
33#define GCC_UNWIND_DW2_FDE_H
34
35#ifndef HIDE_EXPORTS
36#pragma GCC visibility push(default)
37#endif
38
39struct fde_vector
40{
41  const void *orig_data;
42  size_t count;
43  const struct dwarf_fde *array[];
44};
45
46struct object
47{
48  void *pc_begin;
49  void *tbase;
50  void *dbase;
51  union {
52    const struct dwarf_fde *single;
53    struct dwarf_fde **array;
54    struct fde_vector *sort;
55  } u;
56
57  union {
58    struct {
59      unsigned long sorted : 1;
60      unsigned long from_array : 1;
61      unsigned long mixed_encoding : 1;
62      unsigned long encoding : 8;
63      /* ??? Wish there was an easy way to detect a 64-bit host here;
64	 we've got 32 bits left to play with...  */
65      unsigned long count : 21;
66    } b;
67    size_t i;
68  } s;
69
70#ifdef DWARF2_OBJECT_END_PTR_EXTENSION
71  char *fde_end;
72#endif
73
74  struct object *next;
75};
76
77/* This is the original definition of struct object.  While the struct
78   itself was opaque to users, they did know how large it was, and
79   allocate one statically in crtbegin for each DSO.  Keep this around
80   so that we're aware of the static size limitations for the new struct.  */
81struct old_object
82{
83  void *pc_begin;
84  void *pc_end;
85  struct dwarf_fde *fde_begin;
86  struct dwarf_fde **fde_array;
87  size_t count;
88  struct old_object *next;
89};
90
91struct dwarf_eh_bases
92{
93  void *tbase;
94  void *dbase;
95  void *func;
96};
97
98
99extern void __register_frame_info_bases (const void *, struct object *,
100					 void *, void *);
101extern void __register_frame_info (const void *, struct object *);
102extern void __register_frame (void *);
103extern void __register_frame_info_table_bases (void *, struct object *,
104					       void *, void *);
105extern void __register_frame_info_table (void *, struct object *);
106extern void __register_frame_table (void *);
107extern void *__deregister_frame_info (const void *);
108extern void *__deregister_frame_info_bases (const void *);
109extern void __deregister_frame (void *);
110
111
112typedef          int  sword __attribute__ ((mode (SI)));
113typedef unsigned int  uword __attribute__ ((mode (SI)));
114typedef unsigned int  uaddr __attribute__ ((mode (pointer)));
115typedef          int  saddr __attribute__ ((mode (pointer)));
116typedef unsigned char ubyte;
117
118/* Terminology:
119   CIE - Common Information Element
120   FDE - Frame Descriptor Element
121
122   There is one per function, and it describes where the function code
123   is located, and what the register lifetimes and stack layout are
124   within the function.
125
126   The data structures are defined in the DWARF specification, although
127   not in a very readable way (see LITERATURE).
128
129   Every time an exception is thrown, the code needs to locate the FDE
130   for the current function, and starts to look for exception regions
131   from that FDE. This works in a two-level search:
132   a) in a linear search, find the shared image (i.e. DLL) containing
133      the PC
134   b) using the FDE table for that shared object, locate the FDE using
135      binary search (which requires the sorting).  */
136
137/* The first few fields of a CIE.  The CIE_id field is 0 for a CIE,
138   to distinguish it from a valid FDE.  FDEs are aligned to an addressing
139   unit boundary, but the fields within are unaligned.  */
140struct dwarf_cie
141{
142  uword length;
143  sword CIE_id;
144  ubyte version;
145  unsigned char augmentation[];
146} __attribute__ ((packed, aligned (__alignof__ (void *))));
147
148/* The first few fields of an FDE.  */
149struct dwarf_fde
150{
151  uword length;
152  sword CIE_delta;
153  unsigned char pc_begin[];
154} __attribute__ ((packed, aligned (__alignof__ (void *))));
155
156typedef struct dwarf_fde fde;
157
158/* Locate the CIE for a given FDE.  */
159
160static inline const struct dwarf_cie *
161get_cie (const struct dwarf_fde *f)
162{
163  return (void *)&f->CIE_delta - f->CIE_delta;
164}
165
166static inline const fde *
167next_fde (const fde *f)
168{
169  return (const fde *) ((char *) f + f->length + sizeof (f->length));
170}
171
172extern const fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *);
173
174static inline int
175last_fde (struct object *obj __attribute__ ((__unused__)), const fde *f)
176{
177#ifdef DWARF2_OBJECT_END_PTR_EXTENSION
178  return (char *)f == obj->fde_end || f->length == 0;
179#else
180  return f->length == 0;
181#endif
182}
183
184#ifndef HIDE_EXPORTS
185#pragma GCC visibility pop
186#endif
187
188#endif /* unwind-dw2-fde.h */
189