sysdeps/generic/unwind-dw2-fde.h

   1 /* Subroutines needed for unwinding stack frames for exception handling.  */
   2 /* Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   3    Contributed by Jason Merrill <jason@cygnus.com>.
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 In addition to the permissions in the GNU General Public License, the
  13 Free Software Foundation gives you unlimited permission to link the
  14 compiled version of this file into combinations with other programs,
  15 and to distribute those combinations without any restriction coming
  16 from the use of this file.  (The General Public License restrictions
  17 do apply in other respects; for example, they cover modification of
  18 the file, and distribution when not linked into a combine
  19 executable.)
  20
  21 GNU CC is distributed in the hope that it will be useful,
  22 but WITHOUT ANY WARRANTY; without even the implied warranty of
  23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24 GNU General Public License for more details.
  25
  26 You should have received a copy of the GNU General Public License
  27 along with GNU CC; see the file COPYING.  If not, write to
  28 the Free Software Foundation, 59 Temple Place - Suite 330,
  29 Boston, MA 02111-1307, USA.  */
  30
  31
  32 struct fde_vector
  33 {
  34   void *orig_data;
  35   size_t count;
  36   struct dwarf_fde *array __flexarr;
  37 };
  38
  39 #ifdef _LIBC
  40 #include <gccframe.h>
  41 #else
  42 struct object
  43 {
  44   void *pc_begin;
  45   void *tbase;
  46   void *dbase;
  47   union {
  48     struct dwarf_fde *single;
  49     struct dwarf_fde **array;
  50     struct fde_vector *sort;
  51   } u;
  52
  53   union {
  54     struct {
  55       unsigned long sorted : 1;
  56       unsigned long from_array : 1;
  57       unsigned long mixed_encoding : 1;
  58       unsigned long encoding : 8;
  59       /* ??? Wish there was an easy way to detect a 64-bit host here;
  60          we've got 32 bits left to play with... */
  61       unsigned long count : 21;
  62     } b;
  63     size_t i;
  64   } s;
  65
  66   struct object *next;
  67 };
  68 #endif
  69
  70 /* This is the original definition of struct object.  While the struct
  71    itself was opaque to users, they did know how large it was, and
  72    allocate one statically in crtbegin for each DSO.  Keep this around
  73    so that we're aware of the static size limitations for the new struct.  */
  74 struct old_object
  75 {
  76   void *pc_begin;
  77   void *pc_end;
  78   struct dwarf_fde *fde_begin;
  79   struct dwarf_fde **fde_array;
  80   size_t count;
  81   struct old_object *next;
  82 };
  83
  84 struct dwarf_eh_bases
  85 {
  86   void *tbase;
  87   void *dbase;
  88   void *func;
  89 };
  90
  91
  92 extern void __register_frame_info_bases (void *, struct object *,
  93                                          void *, void *);
  94 extern void __register_frame_info (void *, struct object *);
  95 extern void __register_frame (void *);
  96 extern void __register_frame_info_table_bases (void *, struct object *,
  97                                                void *, void *);
  98 extern void __register_frame_info_table (void *, struct object *);
  99 extern void __register_frame_table (void *);
 100 extern void *__deregister_frame_info (void *);
 101 extern void *__deregister_frame_info_bases (void *);
 102 extern void __deregister_frame (void *);
 103
 104 \f
 105 typedef          int  sword __attribute__ ((mode (SI)));
 106 typedef unsigned int  uword __attribute__ ((mode (SI)));
 107 typedef unsigned int  uaddr __attribute__ ((mode (pointer)));
 108 typedef          int  saddr __attribute__ ((mode (pointer)));
 109 typedef unsigned char ubyte;
 110
 111 /* Terminology:
 112    CIE - Common Information Element
 113    FDE - Frame Descriptor Element
 114
 115    There is one per function, and it describes where the function code
 116    is located, and what the register lifetimes and stack layout are
 117    within the function.
 118
 119    The data structures are defined in the DWARF specfication, although
 120    not in a very readable way (see LITERATURE).
 121
 122    Every time an exception is thrown, the code needs to locate the FDE
 123    for the current function, and starts to look for exception regions
 124    from that FDE. This works in a two-level search:
 125    a) in a linear search, find the shared image (i.e. DLL) containing
 126       the PC
 127    b) using the FDE table for that shared object, locate the FDE using
 128       binary search (which requires the sorting).  */
 129
 130 /* The first few fields of a CIE.  The CIE_id field is 0 for a CIE,
 131    to distinguish it from a valid FDE.  FDEs are aligned to an addressing
 132    unit boundary, but the fields within are unaligned.  */
 133 struct dwarf_cie
 134 {
 135   uword length;
 136   sword CIE_id;
 137   ubyte version;
 138   unsigned char augmentation __flexarr;
 139 } __attribute__ ((packed, aligned (__alignof__ (void *))));
 140
 141 /* The first few fields of an FDE.  */
 142 struct dwarf_fde
 143 {
 144   uword length;
 145   sword CIE_delta;
 146   unsigned char pc_begin __flexarr;
 147 } __attribute__ ((packed, aligned (__alignof__ (void *))));
 148
 149 typedef struct dwarf_fde fde;
 150
 151 /* Locate the CIE for a given FDE.  */
 152
 153 static inline struct dwarf_cie *
 154 get_cie (struct dwarf_fde *f)
 155 {
 156   return (void *)&f->CIE_delta - f->CIE_delta;
 157 }
 158
 159 static inline fde *
 160 next_fde (fde *f)
 161 {
 162   return (fde *)((char *)f + f->length + sizeof (f->length));
 163 }
 164
 165 extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *);