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 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 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 #define _UA_END_OF_STACK        16
  91
  92 /* This is an opaque type used to refer to a system-specific data
  93    structure used by the system unwinder. This context is created and
  94    destroyed by the system, and passed to the personality routine
  95    during unwinding.  */
  96 struct _Unwind_Context;
  97
  98 /* Raise an exception, passing along the given exception object.  */
  99 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 100
 101 /* Raise an exception for forced unwinding.  */
 102
 103 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 104      (int, _Unwind_Action, _Unwind_Exception_Class,
 105       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 106
 107 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 108                                                  _Unwind_Stop_Fn,
 109                                                  void *);
 110
 111 /* Helper to invoke the exception_cleanup routine.  */
 112 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 113
 114 /* Resume propagation of an existing exception.  This is used after
 115    e.g. executing cleanup code, and not to implement rethrowing.  */
 116 extern void _Unwind_Resume (struct _Unwind_Exception *);
 117
 118 /* These functions are used for communicating information about the unwind
 119    context (i.e. the unwind descriptors and the user register state) between
 120    the unwind library and the personality routine and landing pad.  Only
 121    selected registers maybe manipulated.  */
 122
 123 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 124 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 125
 126 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 127 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 128
 129 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 130
 131 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 132
 133
 134 /* The personality routine is the function in the C++ (or other language)
 135    runtime library which serves as an interface between the system unwind
 136    library and language-specific exception handling semantics.  It is
 137    specific to the code fragment described by an unwind info block, and
 138    it is always referenced via the pointer in the unwind info block, and
 139    hence it has no ABI-specified name.
 140
 141    Note that this implies that two different C++ implementations can
 142    use different names, and have different contents in the language
 143    specific data area.  Moreover, that the language specific data
 144    area contains no version info because name of the function invoked
 145    provides more effective versioning by detecting at link time the
 146    lack of code to handle the different data format.  */
 147
 148 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 149      (int, _Unwind_Action, _Unwind_Exception_Class,
 150       struct _Unwind_Exception *, struct _Unwind_Context *);
 151
 152 /* @@@ The following alternate entry points are for setjmp/longjmp
 153    based unwinding.  */
 154
 155 struct SjLj_Function_Context;
 156 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 157 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 158
 159 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 160      (struct _Unwind_Exception *);
 161 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 162      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 163 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 164
 165 /* @@@ The following provide access to the base addresses for text
 166    and data-relative addressing in the LDSA.  In order to stay link
 167    compatible with the standard ABI for IA-64, we inline these.  */
 168
 169 #ifdef __ia64__
 170 #include <stdlib.h>
 171
 172 static inline _Unwind_Ptr
 173 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 174 {
 175   /* The GP is stored in R1.  */
 176   return _Unwind_GetGR (_C, 1);
 177 }
 178
 179 static inline _Unwind_Ptr
 180 _Unwind_GetTextRelBase (struct _Unwind_Context *_C)
 181 {
 182   abort ();
 183   return 0;
 184 }
 185 #else
 186 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 187 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 188 #endif
 189
 190 #ifdef __cplusplus
 191 }
 192 #endif