gcc/unwind.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001, 2003, 2004 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    GCC is distributed in the hope that it will be useful, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  14    License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GCC; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19    02111-1307, USA.  */
  20
  21 /* As a special exception, if you include this header file into source
  22    files compiled by GCC, this header file does not by itself cause
  23    the resulting executable to be covered by the GNU General Public
  24    License.  This exception does not however invalidate any other
  25    reasons why the executable file might be covered by the GNU General
  26    Public License.  */
  27
  28 /* This is derived from the C++ ABI for IA-64.  Where we diverge
  29    for cross-architecture compatibility are noted with "@@@".  */
  30
  31 #ifndef _UNWIND_H
  32 #define _UNWIND_H
  33
  34 #ifdef __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 /* Level 1: Base ABI  */
  39
  40 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  41    inefficient for 32-bit and smaller machines.  */
  42 typedef unsigned _Unwind_Word __attribute__((__mode__(__word__)));
  43 typedef signed _Unwind_Sword __attribute__((__mode__(__word__)));
  44 #if defined(__ia64__) && defined(__hpux__)
  45 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  46 #else
  47 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  48 #endif
  49 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  50
  51 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  52    consumer of an exception.  We'll go along with this for now even on
  53    32-bit machines.  We'll need to provide some other option for
  54    16-bit machines and for machines with > 8 bits per byte.  */
  55 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  56
  57 /* The unwind interface uses reason codes in several contexts to
  58    identify the reasons for failures or other actions.  */
  59 typedef enum
  60 {
  61   _URC_NO_REASON = 0,
  62   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  63   _URC_FATAL_PHASE2_ERROR = 2,
  64   _URC_FATAL_PHASE1_ERROR = 3,
  65   _URC_NORMAL_STOP = 4,
  66   _URC_END_OF_STACK = 5,
  67   _URC_HANDLER_FOUND = 6,
  68   _URC_INSTALL_CONTEXT = 7,
  69   _URC_CONTINUE_UNWIND = 8
  70 } _Unwind_Reason_Code;
  71
  72
  73 /* The unwind interface uses a pointer to an exception header object
  74    as its representation of an exception being thrown. In general, the
  75    full representation of an exception object is language- and
  76    implementation-specific, but it will be prefixed by a header
  77    understood by the unwind interface.  */
  78
  79 struct _Unwind_Exception;
  80
  81 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  82                                               struct _Unwind_Exception *);
  83
  84 struct _Unwind_Exception
  85 {
  86   _Unwind_Exception_Class exception_class;
  87   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  88   _Unwind_Word private_1;
  89   _Unwind_Word private_2;
  90
  91   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  92      Taking that literally does not make much sense generically.  Instead we
  93      provide the maximum alignment required by any type for the machine.  */
  94 } __attribute__((__aligned__));
  95
  96
  97 /* The ACTIONS argument to the personality routine is a bitwise OR of one
  98    or more of the following constants.  */
  99 typedef int _Unwind_Action;
 100
 101 #define _UA_SEARCH_PHASE        1
 102 #define _UA_CLEANUP_PHASE       2
 103 #define _UA_HANDLER_FRAME       4
 104 #define _UA_FORCE_UNWIND        8
 105 #define _UA_END_OF_STACK        16
 106
 107 /* This is an opaque type used to refer to a system-specific data
 108    structure used by the system unwinder. This context is created and
 109    destroyed by the system, and passed to the personality routine
 110    during unwinding.  */
 111 struct _Unwind_Context;
 112
 113 /* Raise an exception, passing along the given exception object.  */
 114 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 115
 116 /* Raise an exception for forced unwinding.  */
 117
 118 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 119      (int, _Unwind_Action, _Unwind_Exception_Class,
 120       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 121
 122 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 123                                                  _Unwind_Stop_Fn,
 124                                                  void *);
 125
 126 /* Helper to invoke the exception_cleanup routine.  */
 127 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 128
 129 /* Resume propagation of an existing exception.  This is used after
 130    e.g. executing cleanup code, and not to implement rethrowing.  */
 131 extern void _Unwind_Resume (struct _Unwind_Exception *);
 132
 133 /* @@@ Resume propagation of an FORCE_UNWIND exception, or to rethrow
 134    a normal exception that was handled.  */
 135 extern _Unwind_Reason_Code _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
 136
 137 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 138    is called for every stack frame in the call chain, but no cleanup
 139    actions are performed.  */
 140 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 141      (struct _Unwind_Context *, void *);
 142
 143 extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 144
 145 /* These functions are used for communicating information about the unwind
 146    context (i.e. the unwind descriptors and the user register state) between
 147    the unwind library and the personality routine and landing pad.  Only
 148    selected registers maybe manipulated.  */
 149
 150 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 151 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 152
 153 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 154 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 155
 156 /* @@@ Retrieve the CFA of the given context.  */
 157 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 158
 159 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 160
 161 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 162
 163
 164 /* The personality routine is the function in the C++ (or other language)
 165    runtime library which serves as an interface between the system unwind
 166    library and language-specific exception handling semantics.  It is
 167    specific to the code fragment described by an unwind info block, and
 168    it is always referenced via the pointer in the unwind info block, and
 169    hence it has no ABI-specified name.
 170
 171    Note that this implies that two different C++ implementations can
 172    use different names, and have different contents in the language
 173    specific data area.  Moreover, that the language specific data
 174    area contains no version info because name of the function invoked
 175    provides more effective versioning by detecting at link time the
 176    lack of code to handle the different data format.  */
 177
 178 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 179      (int, _Unwind_Action, _Unwind_Exception_Class,
 180       struct _Unwind_Exception *, struct _Unwind_Context *);
 181
 182 /* @@@ The following alternate entry points are for setjmp/longjmp
 183    based unwinding.  */
 184
 185 struct SjLj_Function_Context;
 186 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 187 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 188
 189 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 190      (struct _Unwind_Exception *);
 191 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 192      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 193 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 194 extern _Unwind_Reason_Code _Unwind_SjLj_Resume_or_Rethrow (struct _Unwind_Exception *);
 195
 196 /* @@@ The following provide access to the base addresses for text
 197    and data-relative addressing in the LDSA.  In order to stay link
 198    compatible with the standard ABI for IA-64, we inline these.  */
 199
 200 #ifdef __ia64__
 201 #include <stdlib.h>
 202
 203 static inline _Unwind_Ptr
 204 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 205 {
 206   /* The GP is stored in R1.  */
 207   return _Unwind_GetGR (_C, 1);
 208 }
 209
 210 static inline _Unwind_Ptr
 211 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 212 {
 213   abort ();
 214   return 0;
 215 }
 216
 217 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
 218 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
 219 #else
 220 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 221 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 222 #endif
 223
 224 /* @@@ Given an address, return the entry point of the function that
 225    contains it.  */
 226 extern void * _Unwind_FindEnclosingFunction (void *pc);
 227
 228 #ifdef __cplusplus
 229 }
 230 #endif
 231
 232 #endif /* unwind.h */