gcc/unwind.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001, 2003 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 /* This is derived from the C++ ABI for IA-64.  Where we diverge
  22    for cross-architecture compatibility are noted with "@@@".  */
  23
  24 #ifdef __cplusplus
  25 extern "C" {
  26 #endif
  27
  28 /* Level 1: Base ABI  */
  29
  30 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  31    inefficient for 32-bit and smaller machines.  */
  32 typedef unsigned _Unwind_Word __attribute__((__mode__(__word__)));
  33 typedef signed _Unwind_Sword __attribute__((__mode__(__word__)));
  34 #if defined(__ia64__) && defined(__hpux__)
  35 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  36 #else
  37 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  38 #endif
  39 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  40
  41 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  42    consumer of an exception.  We'll go along with this for now even on
  43    32-bit machines.  We'll need to provide some other option for
  44    16-bit machines and for machines with > 8 bits per byte.  */
  45 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  46
  47 /* The unwind interface uses reason codes in several contexts to
  48    identify the reasons for failures or other actions.  */
  49 typedef enum
  50 {
  51   _URC_NO_REASON = 0,
  52   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  53   _URC_FATAL_PHASE2_ERROR = 2,
  54   _URC_FATAL_PHASE1_ERROR = 3,
  55   _URC_NORMAL_STOP = 4,
  56   _URC_END_OF_STACK = 5,
  57   _URC_HANDLER_FOUND = 6,
  58   _URC_INSTALL_CONTEXT = 7,
  59   _URC_CONTINUE_UNWIND = 8
  60 } _Unwind_Reason_Code;
  61
  62
  63 /* The unwind interface uses a pointer to an exception header object
  64    as its representation of an exception being thrown. In general, the
  65    full representation of an exception object is language- and
  66    implementation-specific, but it will be prefixed by a header
  67    understood by the unwind interface.  */
  68
  69 struct _Unwind_Exception;
  70
  71 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  72                                               struct _Unwind_Exception *);
  73
  74 struct _Unwind_Exception
  75 {
  76   _Unwind_Exception_Class exception_class;
  77   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  78   _Unwind_Word private_1;
  79   _Unwind_Word private_2;
  80
  81   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  82      Taking that literally does not make much sense generically.  Instead we
  83      provide the maximum alignment required by any type for the machine.  */
  84 } __attribute__((__aligned__));
  85
  86
  87 /* The ACTIONS argument to the personality routine is a bitwise OR of one
  88    or more of the following constants.  */
  89 typedef int _Unwind_Action;
  90
  91 #define _UA_SEARCH_PHASE        1
  92 #define _UA_CLEANUP_PHASE       2
  93 #define _UA_HANDLER_FRAME       4
  94 #define _UA_FORCE_UNWIND        8
  95 #define _UA_END_OF_STACK        16
  96
  97 /* This is an opaque type used to refer to a system-specific data
  98    structure used by the system unwinder. This context is created and
  99    destroyed by the system, and passed to the personality routine
 100    during unwinding.  */
 101 struct _Unwind_Context;
 102
 103 /* Raise an exception, passing along the given exception object.  */
 104 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 105
 106 /* Raise an exception for forced unwinding.  */
 107
 108 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 109      (int, _Unwind_Action, _Unwind_Exception_Class,
 110       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 111
 112 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 113                                                  _Unwind_Stop_Fn,
 114                                                  void *);
 115
 116 /* Helper to invoke the exception_cleanup routine.  */
 117 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 118
 119 /* Resume propagation of an existing exception.  This is used after
 120    e.g. executing cleanup code, and not to implement rethrowing.  */
 121 extern void _Unwind_Resume (struct _Unwind_Exception *);
 122
 123 /* These functions are used for communicating information about the unwind
 124    context (i.e. the unwind descriptors and the user register state) between
 125    the unwind library and the personality routine and landing pad.  Only
 126    selected registers maybe manipulated.  */
 127
 128 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 129 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 130
 131 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 132 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 133
 134 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 135
 136 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 137
 138
 139 /* The personality routine is the function in the C++ (or other language)
 140    runtime library which serves as an interface between the system unwind
 141    library and language-specific exception handling semantics.  It is
 142    specific to the code fragment described by an unwind info block, and
 143    it is always referenced via the pointer in the unwind info block, and
 144    hence it has no ABI-specified name.
 145
 146    Note that this implies that two different C++ implementations can
 147    use different names, and have different contents in the language
 148    specific data area.  Moreover, that the language specific data
 149    area contains no version info because name of the function invoked
 150    provides more effective versioning by detecting at link time the
 151    lack of code to handle the different data format.  */
 152
 153 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 154      (int, _Unwind_Action, _Unwind_Exception_Class,
 155       struct _Unwind_Exception *, struct _Unwind_Context *);
 156
 157 /* @@@ The following alternate entry points are for setjmp/longjmp
 158    based unwinding.  */
 159
 160 struct SjLj_Function_Context;
 161 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 162 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 163
 164 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 165      (struct _Unwind_Exception *);
 166 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 167      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 168 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 169
 170 /* @@@ The following provide access to the base addresses for text
 171    and data-relative addressing in the LDSA.  In order to stay link
 172    compatible with the standard ABI for IA-64, we inline these.  */
 173
 174 #ifdef __ia64__
 175 #include <stdlib.h>
 176
 177 static inline _Unwind_Ptr
 178 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 179 {
 180   /* The GP is stored in R1.  */
 181   return _Unwind_GetGR (_C, 1);
 182 }
 183
 184 static inline _Unwind_Ptr
 185 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 186 {
 187   abort ();
 188   return 0;
 189 }
 190 #else
 191 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 192 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 193 #endif
 194
 195 /* @@@ Given an address, return the entry point of the function that
 196    contains it.  */
 197 extern void * _Unwind_FindEnclosingFunction (void *pc);
 198
 199 #ifdef __cplusplus
 200 }
 201 #endif