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 /* 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 #ifdef __cplusplus
  32 extern "C" {
  33 #endif
  34
  35 /* Level 1: Base ABI  */
  36
  37 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  38    inefficient for 32-bit and smaller machines.  */
  39 typedef unsigned _Unwind_Word __attribute__((__mode__(__word__)));
  40 typedef signed _Unwind_Sword __attribute__((__mode__(__word__)));
  41 #if defined(__ia64__) && defined(__hpux__)
  42 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  43 #else
  44 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  45 #endif
  46 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  47
  48 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  49    consumer of an exception.  We'll go along with this for now even on
  50    32-bit machines.  We'll need to provide some other option for
  51    16-bit machines and for machines with > 8 bits per byte.  */
  52 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  53
  54 /* The unwind interface uses reason codes in several contexts to
  55    identify the reasons for failures or other actions.  */
  56 typedef enum
  57 {
  58   _URC_NO_REASON = 0,
  59   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  60   _URC_FATAL_PHASE2_ERROR = 2,
  61   _URC_FATAL_PHASE1_ERROR = 3,
  62   _URC_NORMAL_STOP = 4,
  63   _URC_END_OF_STACK = 5,
  64   _URC_HANDLER_FOUND = 6,
  65   _URC_INSTALL_CONTEXT = 7,
  66   _URC_CONTINUE_UNWIND = 8
  67 } _Unwind_Reason_Code;
  68
  69
  70 /* The unwind interface uses a pointer to an exception header object
  71    as its representation of an exception being thrown. In general, the
  72    full representation of an exception object is language- and
  73    implementation-specific, but it will be prefixed by a header
  74    understood by the unwind interface.  */
  75
  76 struct _Unwind_Exception;
  77
  78 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  79                                               struct _Unwind_Exception *);
  80
  81 struct _Unwind_Exception
  82 {
  83   _Unwind_Exception_Class exception_class;
  84   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  85   _Unwind_Word private_1;
  86   _Unwind_Word private_2;
  87
  88   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  89      Taking that literally does not make much sense generically.  Instead we
  90      provide the maximum alignment required by any type for the machine.  */
  91 } __attribute__((__aligned__));
  92
  93
  94 /* The ACTIONS argument to the personality routine is a bitwise OR of one
  95    or more of the following constants.  */
  96 typedef int _Unwind_Action;
  97
  98 #define _UA_SEARCH_PHASE        1
  99 #define _UA_CLEANUP_PHASE       2
 100 #define _UA_HANDLER_FRAME       4
 101 #define _UA_FORCE_UNWIND        8
 102 #define _UA_END_OF_STACK        16
 103
 104 /* This is an opaque type used to refer to a system-specific data
 105    structure used by the system unwinder. This context is created and
 106    destroyed by the system, and passed to the personality routine
 107    during unwinding.  */
 108 struct _Unwind_Context;
 109
 110 /* Raise an exception, passing along the given exception object.  */
 111 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 112
 113 /* Raise an exception for forced unwinding.  */
 114
 115 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 116      (int, _Unwind_Action, _Unwind_Exception_Class,
 117       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 118
 119 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 120                                                  _Unwind_Stop_Fn,
 121                                                  void *);
 122
 123 /* Helper to invoke the exception_cleanup routine.  */
 124 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 125
 126 /* Resume propagation of an existing exception.  This is used after
 127    e.g. executing cleanup code, and not to implement rethrowing.  */
 128 extern void _Unwind_Resume (struct _Unwind_Exception *);
 129
 130 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 131    is called for every stack frame in the call chain, but no cleanup
 132    actions are performed.  */
 133 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 134      (struct _Unwind_Context *, void *);
 135
 136 extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 137
 138 /* These functions are used for communicating information about the unwind
 139    context (i.e. the unwind descriptors and the user register state) between
 140    the unwind library and the personality routine and landing pad.  Only
 141    selected registers maybe manipulated.  */
 142
 143 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 144 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 145
 146 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 147 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 148
 149 /* @@@ Retrieve the CFA of the given context.  */
 150 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 151
 152 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 153
 154 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 155
 156
 157 /* The personality routine is the function in the C++ (or other language)
 158    runtime library which serves as an interface between the system unwind
 159    library and language-specific exception handling semantics.  It is
 160    specific to the code fragment described by an unwind info block, and
 161    it is always referenced via the pointer in the unwind info block, and
 162    hence it has no ABI-specified name.
 163
 164    Note that this implies that two different C++ implementations can
 165    use different names, and have different contents in the language
 166    specific data area.  Moreover, that the language specific data
 167    area contains no version info because name of the function invoked
 168    provides more effective versioning by detecting at link time the
 169    lack of code to handle the different data format.  */
 170
 171 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 172      (int, _Unwind_Action, _Unwind_Exception_Class,
 173       struct _Unwind_Exception *, struct _Unwind_Context *);
 174
 175 /* @@@ The following alternate entry points are for setjmp/longjmp
 176    based unwinding.  */
 177
 178 struct SjLj_Function_Context;
 179 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 180 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 181
 182 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 183      (struct _Unwind_Exception *);
 184 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 185      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 186 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 187
 188 /* @@@ The following provide access to the base addresses for text
 189    and data-relative addressing in the LDSA.  In order to stay link
 190    compatible with the standard ABI for IA-64, we inline these.  */
 191
 192 #ifdef __ia64__
 193 #include <stdlib.h>
 194
 195 static inline _Unwind_Ptr
 196 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 197 {
 198   /* The GP is stored in R1.  */
 199   return _Unwind_GetGR (_C, 1);
 200 }
 201
 202 static inline _Unwind_Ptr
 203 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 204 {
 205   abort ();
 206   return 0;
 207 }
 208 #else
 209 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 210 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 211 #endif
 212
 213 /* @@@ Given an address, return the entry point of the function that
 214    contains it.  */
 215 extern void * _Unwind_FindEnclosingFunction (void *pc);
 216
 217 #ifdef __cplusplus
 218 }
 219 #endif