gcc/unwind-dw2-fde.h

   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
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 In addition to the permissions in the GNU General Public License, the
  14 Free Software Foundation gives you unlimited permission to link the
  15 compiled version of this file into combinations with other programs,
  16 and to distribute those combinations without any restriction coming
  17 from the use of this file.  (The General Public License restrictions
  18 do apply in other respects; for example, they cover modification of
  19 the file, and distribution when not linked into a combine
  20 executable.)
  21
  22 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  23 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  24 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  25 for more details.
  26
  27 You should have received a copy of the GNU General Public License
  28 along with GCC; see the file COPYING.  If not, write to the Free
  29 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  30 02111-1307, USA.  */
  31
  32
  33 struct fde_vector
  34 {
  35   void *orig_data;
  36   size_t count;
  37   struct dwarf_fde *array[];
  38 };
  39
  40 struct 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.  */
  71 struct 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
  81 struct dwarf_eh_bases
  82 {
  83   void *tbase;
  84   void *dbase;
  85   void *func;
  86 };
  87
  88
  89 extern void __register_frame_info_bases (void *, struct object *,
  90                                          void *, void *);
  91 extern void __register_frame_info (void *, struct object *);
  92 extern void __register_frame (void *);
  93 extern void __register_frame_info_table_bases (void *, struct object *,
  94                                                void *, void *);
  95 extern void __register_frame_info_table (void *, struct object *);
  96 extern void __register_frame_table (void *);
  97 extern void *__deregister_frame_info (void *);
  98 extern void *__deregister_frame_info_bases (void *);
  99 extern void __deregister_frame (void *);
 100
 101 \f
 102 typedef          int  sword __attribute__ ((mode (SI)));
 103 typedef unsigned int  uword __attribute__ ((mode (SI)));
 104 typedef unsigned int  uaddr __attribute__ ((mode (pointer)));
 105 typedef          int  saddr __attribute__ ((mode (pointer)));
 106 typedef 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.  */
 130 struct 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.  */
 139 struct dwarf_fde
 140 {
 141   uword length;
 142   sword CIE_delta;
 143   unsigned char pc_begin[];
 144 } __attribute__ ((packed, aligned (__alignof__ (void *))));
 145
 146 typedef struct dwarf_fde fde;
 147
 148 /* Locate the CIE for a given FDE.  */
 149
 150 static inline struct dwarf_cie *
 151 get_cie (struct dwarf_fde *f)
 152 {
 153   return (void *)&f->CIE_delta - f->CIE_delta;
 154 }
 155
 156 static inline fde *
 157 next_fde (fde *f)
 158 {
 159   return (fde *) ((char *) f + f->length + sizeof (f->length));
 160 }
 161
 162 extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *);