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 #pragma GCC visibility push(default)
  35
  36 #ifdef __cplusplus
  37 extern "C" {
  38 #endif
  39
  40 /* Level 1: Base ABI  */
  41
  42 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  43    inefficient for 32-bit and smaller machines.  */
  44 typedef unsigned _Unwind_Word __attribute__((__mode__(__word__)));
  45 typedef signed _Unwind_Sword __attribute__((__mode__(__word__)));
  46 #if defined(__ia64__) && defined(__hpux__)
  47 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  48 #else
  49 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  50 #endif
  51 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  52
  53 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  54    consumer of an exception.  We'll go along with this for now even on
  55    32-bit machines.  We'll need to provide some other option for
  56    16-bit machines and for machines with > 8 bits per byte.  */
  57 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  58
  59 /* The unwind interface uses reason codes in several contexts to
  60    identify the reasons for failures or other actions.  */
  61 typedef enum
  62 {
  63   _URC_NO_REASON = 0,
  64   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  65   _URC_FATAL_PHASE2_ERROR = 2,
  66   _URC_FATAL_PHASE1_ERROR = 3,
  67   _URC_NORMAL_STOP = 4,
  68   _URC_END_OF_STACK = 5,
  69   _URC_HANDLER_FOUND = 6,
  70   _URC_INSTALL_CONTEXT = 7,
  71   _URC_CONTINUE_UNWIND = 8
  72 } _Unwind_Reason_Code;
  73
  74
  75 /* The unwind interface uses a pointer to an exception header object
  76    as its representation of an exception being thrown. In general, the
  77    full representation of an exception object is language- and
  78    implementation-specific, but it will be prefixed by a header
  79    understood by the unwind interface.  */
  80
  81 struct _Unwind_Exception;
  82
  83 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  84                                               struct _Unwind_Exception *);
  85
  86 struct _Unwind_Exception
  87 {
  88   _Unwind_Exception_Class exception_class;
  89   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  90   _Unwind_Word private_1;
  91   _Unwind_Word private_2;
  92
  93   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  94      Taking that literally does not make much sense generically.  Instead we
  95      provide the maximum alignment required by any type for the machine.  */
  96 } __attribute__((__aligned__));
  97
  98
  99 /* The ACTIONS argument to the personality routine is a bitwise OR of one
 100    or more of the following constants.  */
 101 typedef int _Unwind_Action;
 102
 103 #define _UA_SEARCH_PHASE        1
 104 #define _UA_CLEANUP_PHASE       2
 105 #define _UA_HANDLER_FRAME       4
 106 #define _UA_FORCE_UNWIND        8
 107 #define _UA_END_OF_STACK        16
 108
 109 /* This is an opaque type used to refer to a system-specific data
 110    structure used by the system unwinder. This context is created and
 111    destroyed by the system, and passed to the personality routine
 112    during unwinding.  */
 113 struct _Unwind_Context;
 114
 115 /* Raise an exception, passing along the given exception object.  */
 116 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 117
 118 /* Raise an exception for forced unwinding.  */
 119
 120 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 121      (int, _Unwind_Action, _Unwind_Exception_Class,
 122       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 123
 124 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 125                                                  _Unwind_Stop_Fn,
 126                                                  void *);
 127
 128 /* Helper to invoke the exception_cleanup routine.  */
 129 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 130
 131 /* Resume propagation of an existing exception.  This is used after
 132    e.g. executing cleanup code, and not to implement rethrowing.  */
 133 extern void _Unwind_Resume (struct _Unwind_Exception *);
 134
 135 /* @@@ Resume propagation of an FORCE_UNWIND exception, or to rethrow
 136    a normal exception that was handled.  */
 137 extern _Unwind_Reason_Code _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
 138
 139 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 140    is called for every stack frame in the call chain, but no cleanup
 141    actions are performed.  */
 142 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 143      (struct _Unwind_Context *, void *);
 144
 145 extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 146
 147 /* These functions are used for communicating information about the unwind
 148    context (i.e. the unwind descriptors and the user register state) between
 149    the unwind library and the personality routine and landing pad.  Only
 150    selected registers maybe manipulated.  */
 151
 152 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 153 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 154
 155 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 156 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 157
 158 /* @@@ Retrieve the CFA of the given context.  */
 159 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 160
 161 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 162
 163 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 164
 165
 166 /* The personality routine is the function in the C++ (or other language)
 167    runtime library which serves as an interface between the system unwind
 168    library and language-specific exception handling semantics.  It is
 169    specific to the code fragment described by an unwind info block, and
 170    it is always referenced via the pointer in the unwind info block, and
 171    hence it has no ABI-specified name.
 172
 173    Note that this implies that two different C++ implementations can
 174    use different names, and have different contents in the language
 175    specific data area.  Moreover, that the language specific data
 176    area contains no version info because name of the function invoked
 177    provides more effective versioning by detecting at link time the
 178    lack of code to handle the different data format.  */
 179
 180 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 181      (int, _Unwind_Action, _Unwind_Exception_Class,
 182       struct _Unwind_Exception *, struct _Unwind_Context *);
 183
 184 /* @@@ The following alternate entry points are for setjmp/longjmp
 185    based unwinding.  */
 186
 187 struct SjLj_Function_Context;
 188 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 189 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 190
 191 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 192      (struct _Unwind_Exception *);
 193 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 194      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 195 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 196 extern _Unwind_Reason_Code _Unwind_SjLj_Resume_or_Rethrow (struct _Unwind_Exception *);
 197
 198 /* @@@ The following provide access to the base addresses for text
 199    and data-relative addressing in the LDSA.  In order to stay link
 200    compatible with the standard ABI for IA-64, we inline these.  */
 201
 202 #ifdef __ia64__
 203 #include <stdlib.h>
 204
 205 static inline _Unwind_Ptr
 206 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 207 {
 208   /* The GP is stored in R1.  */
 209   return _Unwind_GetGR (_C, 1);
 210 }
 211
 212 static inline _Unwind_Ptr
 213 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 214 {
 215   abort ();
 216   return 0;
 217 }
 218
 219 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
 220 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
 221 #else
 222 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 223 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 224 #endif
 225
 226 /* @@@ Given an address, return the entry point of the function that
 227    contains it.  */
 228 extern void * _Unwind_FindEnclosingFunction (void *pc);
 229
 230 #ifdef __cplusplus
 231 }
 232 #endif
 233
 234 #pragma GCC visibility pop
 235
 236 #endif /* unwind.h */