unwind-dw2-fde.h revision 117395 
1/* Subroutines needed for unwinding stack frames for exception handling.  */
2/* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
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#ifdef DWARF2_OBJECT_END_PTR_EXTENSION
65  char *fde_end;
66#endif
67
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.  */
75struct old_object
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;
82  struct old_object *next;
83};
84
85struct dwarf_eh_bases
86{
87  void *tbase;
88  void *dbase;
89  void *func;
90};
91
92
93extern void __register_frame_info_bases (void *, struct object *,
94					 void *, void *);
95extern void __register_frame_info (void *, struct object *);
96extern void __register_frame (void *);
97extern void __register_frame_info_table_bases (void *, struct object *,
98					       void *, void *);
99extern void __register_frame_info_table (void *, struct object *);
100extern void __register_frame_table (void *);
101extern void *__deregister_frame_info (void *);
102extern void *__deregister_frame_info_bases (void *);
103extern void __deregister_frame (void *);
104
105
106typedef          int  sword __attribute__ ((mode (SI)));
107typedef unsigned int  uword __attribute__ ((mode (SI)));
108typedef unsigned int  uaddr __attribute__ ((mode (pointer)));
109typedef          int  saddr __attribute__ ((mode (pointer)));
110typedef 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
120   The data structures are defined in the DWARF specification, although
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
129      binary search (which requires the sorting).  */
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.  */
134struct 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.  */
143struct dwarf_fde
144{
145  uword length;
146  sword CIE_delta;
147  unsigned char pc_begin[];
148} __attribute__ ((packed, aligned (__alignof__ (void *))));
149
150typedef struct dwarf_fde fde;
151
152/* Locate the CIE for a given FDE.  */
153
154static inline struct dwarf_cie *
155get_cie (struct dwarf_fde *f)
156{
157  return (void *)&f->CIE_delta - f->CIE_delta;
158}
159
160static inline fde *
161next_fde (fde *f)
162{
163  return (fde *) ((char *) f + f->length + sizeof (f->length));
164}
165
166extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *);
167
168static inline int
169last_fde (struct object *obj __attribute__ ((__unused__)), fde *f)
170{
171#ifdef DWARF2_OBJECT_END_PTR_EXTENSION
172  return (char *)f == obj->fde_end || f->length == 0;
173#else
174  return f->length == 0;
175#endif
176}
177