unwind-dw2-fde.h revision 96489 
1/* Subroutines needed for unwinding stack frames for exception handling.  */
2/* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
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, 59 Temple Place - Suite 330, Boston, MA
3002111-1307, USA.  */
31
32
33struct fde_vector
34{
35  void *orig_data;
36  size_t count;
37  struct dwarf_fde *array[];
38};
39
40struct object
41{
42  void *pc_begin;
43  void *tbase;
44  void *dbase;
45  union {
46    struct dwarf_fde *single;
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;
58	 we've got 32 bits left to play with...  */
59      unsigned long count : 21;
60    } b;
61    size_t i;
62  } s;
63
64  struct object *next;
65};
66
67/* This is the original definition of struct object.  While the struct
68   itself was opaque to users, they did know how large it was, and
69   allocate one statically in crtbegin for each DSO.  Keep this around
70   so that we're aware of the static size limitations for the new struct.  */
71struct old_object
72{
73  void *pc_begin;
74  void *pc_end;
75  struct dwarf_fde *fde_begin;
76  struct dwarf_fde **fde_array;
77  size_t count;
78  struct old_object *next;
79};
80
81struct dwarf_eh_bases
82{
83  void *tbase;
84  void *dbase;
85  void *func;
86};
87
88
89extern void __register_frame_info_bases (void *, struct object *,
90					 void *, void *);
91extern void __register_frame_info (void *, struct object *);
92extern void __register_frame (void *);
93extern void __register_frame_info_table_bases (void *, struct object *,
94					       void *, void *);
95extern void __register_frame_info_table (void *, struct object *);
96extern void __register_frame_table (void *);
97extern void *__deregister_frame_info (void *);
98extern void *__deregister_frame_info_bases (void *);
99extern void __deregister_frame (void *);
100
101
102typedef          int  sword __attribute__ ((mode (SI)));
103typedef unsigned int  uword __attribute__ ((mode (SI)));
104typedef unsigned int  uaddr __attribute__ ((mode (pointer)));
105typedef          int  saddr __attribute__ ((mode (pointer)));
106typedef unsigned char ubyte;
107
108/* Terminology:
109   CIE - Common Information Element
110   FDE - Frame Descriptor Element
111
112   There is one per function, and it describes where the function code
113   is located, and what the register lifetimes and stack layout are
114   within the function.
115
116   The data structures are defined in the DWARF specification, although
117   not in a very readable way (see LITERATURE).
118
119   Every time an exception is thrown, the code needs to locate the FDE
120   for the current function, and starts to look for exception regions
121   from that FDE. This works in a two-level search:
122   a) in a linear search, find the shared image (i.e. DLL) containing
123      the PC
124   b) using the FDE table for that shared object, locate the FDE using
125      binary search (which requires the sorting).  */
126
127/* The first few fields of a CIE.  The CIE_id field is 0 for a CIE,
128   to distinguish it from a valid FDE.  FDEs are aligned to an addressing
129   unit boundary, but the fields within are unaligned.  */
130struct dwarf_cie
131{
132  uword length;
133  sword CIE_id;
134  ubyte version;
135  unsigned char augmentation[];
136} __attribute__ ((packed, aligned (__alignof__ (void *))));
137
138/* The first few fields of an FDE.  */
139struct dwarf_fde
140{
141  uword length;
142  sword CIE_delta;
143  unsigned char pc_begin[];
144} __attribute__ ((packed, aligned (__alignof__ (void *))));
145
146typedef struct dwarf_fde fde;
147
148/* Locate the CIE for a given FDE.  */
149
150static inline struct dwarf_cie *
151get_cie (struct dwarf_fde *f)
152{
153  return (void *)&f->CIE_delta - f->CIE_delta;
154}
155
156static inline fde *
157next_fde (fde *f)
158{
159  return (fde *) ((char *) f + f->length + sizeof (f->length));
160}
161
162extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *);
163