1 /* Subroutines needed for unwinding stack frames for exception handling. */ 2 /* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2009 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 3, or (at your option) any later 11 version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 Under Section 7 of GPL version 3, you are granted additional 19 permissions described in the GCC Runtime Library Exception, version 20 3.1, as published by the Free Software Foundation. 21 22 You should have received a copy of the GNU General Public License and 23 a copy of the GCC Runtime Library Exception along with this program; 24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 25 <http://www.gnu.org/licenses/>. */ 26 27 #ifndef GCC_UNWIND_DW2_FDE_H 28 #define GCC_UNWIND_DW2_FDE_H 29 30 #ifndef HIDE_EXPORTS 31 #pragma GCC visibility push(default) 32 #endif 33 34 struct fde_vector 35 { 36 const void *orig_data; 37 size_t count; 38 const struct dwarf_fde *array[]; 39 }; 40 41 struct object 42 { 43 void *pc_begin; 44 void *tbase; 45 void *dbase; 46 union { 47 const struct dwarf_fde *single; 48 struct dwarf_fde **array; 49 struct fde_vector *sort; 50 } u; 51 52 union { 53 struct { 54 unsigned long sorted : 1; 55 unsigned long from_array : 1; 56 unsigned long mixed_encoding : 1; 57 unsigned long encoding : 8; 58 /* ??? Wish there was an easy way to detect a 64-bit host here; 59 we've got 32 bits left to play with... */ 60 unsigned long count : 21; 61 } b; 62 size_t i; 63 } s; 64 65 #ifdef DWARF2_OBJECT_END_PTR_EXTENSION 66 char *fde_end; 67 #endif 68 69 struct object *next; 70 }; 71 72 /* This is the original definition of struct object. While the struct 73 itself was opaque to users, they did know how large it was, and 74 allocate one statically in crtbegin for each DSO. Keep this around 75 so that we're aware of the static size limitations for the new struct. */ 76 struct old_object 77 { 78 void *pc_begin; 79 void *pc_end; 80 struct dwarf_fde *fde_begin; 81 struct dwarf_fde **fde_array; 82 size_t count; 83 struct old_object *next; 84 }; 85 86 struct dwarf_eh_bases 87 { 88 void *tbase; 89 void *dbase; 90 void *func; 91 }; 92 93 94 extern void __register_frame_info_bases (const void *, struct object *, 95 void *, void *); 96 extern void __register_frame_info (const void *, struct object *); 97 extern void __register_frame (void *); 98 extern void __register_frame_info_table_bases (void *, struct object *, 99 void *, void *); 100 extern void __register_frame_info_table (void *, struct object *); 101 extern void __register_frame_table (void *); 102 extern void *__deregister_frame_info (const void *); 103 extern void *__deregister_frame_info_bases (const void *); 104 extern void __deregister_frame (void *); 105 106 107 typedef int sword __attribute__ ((mode (SI))); 108 typedef unsigned int uword __attribute__ ((mode (SI))); 109 typedef unsigned int uaddr __attribute__ ((mode (pointer))); 110 typedef int saddr __attribute__ ((mode (pointer))); 111 typedef unsigned char ubyte; 112 113 /* Terminology: 114 CIE - Common Information Element 115 FDE - Frame Descriptor Element 116 117 There is one per function, and it describes where the function code 118 is located, and what the register lifetimes and stack layout are 119 within the function. 120 121 The data structures are defined in the DWARF specification, although 122 not in a very readable way (see LITERATURE). 123 124 Every time an exception is thrown, the code needs to locate the FDE 125 for the current function, and starts to look for exception regions 126 from that FDE. This works in a two-level search: 127 a) in a linear search, find the shared image (i.e. DLL) containing 128 the PC 129 b) using the FDE table for that shared object, locate the FDE using 130 binary search (which requires the sorting). */ 131 132 /* The first few fields of a CIE. The CIE_id field is 0 for a CIE, 133 to distinguish it from a valid FDE. FDEs are aligned to an addressing 134 unit boundary, but the fields within are unaligned. */ 135 struct dwarf_cie 136 { 137 uword length; 138 sword CIE_id; 139 ubyte version; 140 unsigned char augmentation[]; 141 } __attribute__ ((packed, aligned (__alignof__ (void *)))); 142 143 /* The first few fields of an FDE. */ 144 struct dwarf_fde 145 { 146 uword length; 147 sword CIE_delta; 148 unsigned char pc_begin[]; 149 } __attribute__ ((packed, aligned (__alignof__ (void *)))); 150 151 typedef struct dwarf_fde fde; 152 153 /* Locate the CIE for a given FDE. */ 154 155 static inline const struct dwarf_cie * 156 get_cie (const struct dwarf_fde *f) 157 { 158 return (const void *)&f->CIE_delta - f->CIE_delta; 159 } 160 161 static inline const fde * 162 next_fde (const fde *f) 163 { 164 return (const fde *) ((const char *) f + f->length + sizeof (f->length)); 165 } 166 167 extern const fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *); 168 169 static inline int 170 last_fde (struct object *obj __attribute__ ((__unused__)), const fde *f) 171 { 172 #ifdef DWARF2_OBJECT_END_PTR_EXTENSION 173 return (char *)f == obj->fde_end || f->length == 0; 174 #else 175 return f->length == 0; 176 #endif 177 } 178 179 #ifndef HIDE_EXPORTS 180 #pragma GCC visibility pop 181 #endif 182 183 #endif /* unwind-dw2-fde.h */ 184