gcc/unwind.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001 Free Software Foundation, Inc.
   3
   4    This file is part of GNU CC.
   5
   6    GNU CC is free software; you can redistribute it and/or modify
   7    it 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    GNU CC is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GNU CC; see the file COPYING.  If not, write to
  18    the Free Software Foundation, 59 Temple Place - Suite 330,
  19    Boston, MA 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 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  35
  36 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  37    consumer of an exception.  We'll go along with this for now even on
  38    32-bit machines.  We'll need to provide some other option for
  39    16-bit machines and for machines with > 8 bits per byte.  */
  40 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  41
  42 /* The unwind interface uses reason codes in several contexts to
  43    identify the reasons for failures or other actions.  */
  44 typedef enum
  45 {
  46   _URC_NO_REASON = 0,
  47   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  48   _URC_FATAL_PHASE2_ERROR = 2,
  49   _URC_FATAL_PHASE1_ERROR = 3,
  50   _URC_NORMAL_STOP = 4,
  51   _URC_END_OF_STACK = 5,
  52   _URC_HANDLER_FOUND = 6,
  53   _URC_INSTALL_CONTEXT = 7,
  54   _URC_CONTINUE_UNWIND = 8
  55 } _Unwind_Reason_Code;
  56
  57
  58 /* The unwind interface uses a pointer to an exception header object
  59    as its representation of an exception being thrown. In general, the
  60    full representation of an exception object is language- and
  61    implementation-specific, but it will be prefixed by a header
  62    understood by the unwind interface.  */
  63
  64 struct _Unwind_Exception;
  65
  66 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  67                                               struct _Unwind_Exception *);
  68
  69 struct _Unwind_Exception
  70 {
  71   _Unwind_Exception_Class exception_class;
  72   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  73   _Unwind_Word private_1;
  74   _Unwind_Word private_2;
  75
  76   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  77      Taking that literally does not make much sense generically.  Instead we
  78      provide the maximum alignment required by any type for the machine.  */
  79 } __attribute__((__aligned__));
  80
  81
  82 /* The ACTIONS argument to the personality routine is a bitwise OR of one
  83    or more of the following constants.  */
  84 typedef int _Unwind_Action;
  85
  86 #define _UA_SEARCH_PHASE        1
  87 #define _UA_CLEANUP_PHASE       2
  88 #define _UA_HANDLER_FRAME       4
  89 #define _UA_FORCE_UNWIND        8
  90
  91 /* This is an opaque type used to refer to a system-specific data
  92    structure used by the system unwinder. This context is created and
  93    destroyed by the system, and passed to the personality routine
  94    during unwinding.  */
  95 struct _Unwind_Context;
  96
  97 /* Raise an exception, passing along the given exception object.  */
  98 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
  99
 100 /* Raise an exception for forced unwinding.  */
 101
 102 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 103      (int, _Unwind_Action, _Unwind_Exception_Class,
 104       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 105
 106 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 107                                                  _Unwind_Stop_Fn,
 108                                                  void *);
 109
 110 /* Helper to invoke the exception_cleanup routine.  */
 111 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 112
 113 /* Resume propagation of an existing exception.  This is used after
 114    e.g. executing cleanup code, and not to implement rethrowing.  */
 115 extern void _Unwind_Resume (struct _Unwind_Exception *);
 116
 117 /* These functions are used for communicating information about the unwind
 118    context (i.e. the unwind descriptors and the user register state) between
 119    the unwind library and the personality routine and landing pad.  Only
 120    selected registers maybe manipulated.  */
 121
 122 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 123 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 124
 125 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 126 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 127
 128 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 129
 130 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 131
 132
 133 /* The personality routine is the function in the C++ (or other language)
 134    runtime library which serves as an interface between the system unwind
 135    library and language-specific exception handling semantics.  It is
 136    specific to the code fragment described by an unwind info block, and
 137    it is always referenced via the pointer in the unwind info block, and
 138    hence it has no ABI-specified name.
 139
 140    Note that this implies that two different C++ implementations can
 141    use different names, and have different contents in the language
 142    specific data area.  Moreover, that the language specific data
 143    area contains no version info because name of the function invoked
 144    provides more effective versioning by detecting at link time the
 145    lack of code to handle the different data format.  */
 146
 147 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 148      (int, _Unwind_Action, _Unwind_Exception_Class,
 149       struct _Unwind_Exception *, struct _Unwind_Context *);
 150
 151 /* @@@ The following alternate entry points are for setjmp/longjmp
 152    based unwinding.  */
 153
 154 struct SjLj_Function_Context;
 155 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 156 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 157
 158 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 159      (struct _Unwind_Exception *);
 160 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 161      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 162 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 163
 164 #ifdef __cplusplus
 165 }
 166 #endif