sysdeps/generic/unwind.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001-2017 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library 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 GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 /* This is derived from the C++ ABI for IA-64.  Where we diverge
  21    for cross-architecture compatibility are noted with "@@@".  */
  22
  23 #ifndef _UNWIND_H
  24 #define _UNWIND_H       1
  25
  26 #ifdef __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 /* Level 1: Base ABI  */
  31
  32 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  33    inefficient for 32-bit and smaller machines.  */
  34 typedef unsigned _Unwind_Word __attribute__((__mode__(__unwind_word__)));
  35 typedef signed _Unwind_Sword __attribute__((__mode__(__unwind_word__)));
  36 #if defined(__ia64__) && defined(__hpux__)
  37 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  38 #else
  39 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  40 #endif
  41 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  42
  43 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  44    consumer of an exception.  We'll go along with this for now even on
  45    32-bit machines.  We'll need to provide some other option for
  46    16-bit machines and for machines with > 8 bits per byte.  */
  47 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  48
  49 /* The unwind interface uses reason codes in several contexts to
  50    identify the reasons for failures or other actions.  */
  51 typedef enum
  52 {
  53   _URC_NO_REASON = 0,
  54   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  55   _URC_FATAL_PHASE2_ERROR = 2,
  56   _URC_FATAL_PHASE1_ERROR = 3,
  57   _URC_NORMAL_STOP = 4,
  58   _URC_END_OF_STACK = 5,
  59   _URC_HANDLER_FOUND = 6,
  60   _URC_INSTALL_CONTEXT = 7,
  61   _URC_CONTINUE_UNWIND = 8
  62 } _Unwind_Reason_Code;
  63
  64
  65 /* The unwind interface uses a pointer to an exception header object
  66    as its representation of an exception being thrown. In general, the
  67    full representation of an exception object is language- and
  68    implementation-specific, but it will be prefixed by a header
  69    understood by the unwind interface.  */
  70
  71 struct _Unwind_Exception;
  72
  73 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  74                                               struct _Unwind_Exception *);
  75
  76 struct _Unwind_Exception
  77 {
  78   _Unwind_Exception_Class exception_class;
  79   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  80   _Unwind_Word private_1;
  81   _Unwind_Word private_2;
  82
  83   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  84      Taking that literally does not make much sense generically.  Instead we
  85      provide the maximum alignment required by any type for the machine.  */
  86 } __attribute__((__aligned__));
  87
  88
  89 /* The ACTIONS argument to the personality routine is a bitwise OR of one
  90    or more of the following constants.  */
  91 typedef int _Unwind_Action;
  92
  93 #define _UA_SEARCH_PHASE        1
  94 #define _UA_CLEANUP_PHASE       2
  95 #define _UA_HANDLER_FRAME       4
  96 #define _UA_FORCE_UNWIND        8
  97 #define _UA_END_OF_STACK        16
  98
  99 /* This is an opaque type used to refer to a system-specific data
 100    structure used by the system unwinder. This context is created and
 101    destroyed by the system, and passed to the personality routine
 102    during unwinding.  */
 103 struct _Unwind_Context;
 104
 105 /* Raise an exception, passing along the given exception object.  */
 106 extern _Unwind_Reason_Code _Unwind_RaiseException (struct _Unwind_Exception *);
 107
 108 /* Raise an exception for forced unwinding.  */
 109
 110 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 111      (int, _Unwind_Action, _Unwind_Exception_Class,
 112       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 113
 114 extern _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *,
 115                                                  _Unwind_Stop_Fn,
 116                                                  void *);
 117
 118 /* Helper to invoke the exception_cleanup routine.  */
 119 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 120
 121 /* Resume propagation of an existing exception.  This is used after
 122    e.g. executing cleanup code, and not to implement rethrowing.  */
 123 extern void _Unwind_Resume (struct _Unwind_Exception *);
 124
 125 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 126    is called for every stack frame in the call chain, but no cleanup
 127    actions are performed.  */
 128 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 129      (struct _Unwind_Context *, void *);
 130
 131 extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 132
 133 /* These functions are used for communicating information about the unwind
 134    context (i.e. the unwind descriptors and the user register state) between
 135    the unwind library and the personality routine and landing pad.  Only
 136    selected registers maybe manipulated.  */
 137
 138 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 139 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 140
 141 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 142 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 143
 144 /* @@@ Retrieve the CFA of the given context.  */
 145 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 146
 147 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 148
 149 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 150
 151
 152 /* The personality routine is the function in the C++ (or other language)
 153    runtime library which serves as an interface between the system unwind
 154    library and language-specific exception handling semantics.  It is
 155    specific to the code fragment described by an unwind info block, and
 156    it is always referenced via the pointer in the unwind info block, and
 157    hence it has no ABI-specified name.
 158
 159    Note that this implies that two different C++ implementations can
 160    use different names, and have different contents in the language
 161    specific data area.  Moreover, that the language specific data
 162    area contains no version info because name of the function invoked
 163    provides more effective versioning by detecting at link time the
 164    lack of code to handle the different data format.  */
 165
 166 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 167      (int, _Unwind_Action, _Unwind_Exception_Class,
 168       struct _Unwind_Exception *, struct _Unwind_Context *);
 169
 170 /* @@@ The following alternate entry points are for setjmp/longjmp
 171    based unwinding.  */
 172
 173 struct SjLj_Function_Context;
 174 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 175 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 176
 177 extern _Unwind_Reason_Code _Unwind_SjLj_RaiseException
 178      (struct _Unwind_Exception *);
 179 extern _Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind
 180      (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 181 extern void _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 182
 183 /* @@@ The following provide access to the base addresses for text
 184    and data-relative addressing in the LDSA.  In order to stay link
 185    compatible with the standard ABI for IA-64, we inline these.  */
 186
 187 #ifdef __ia64__
 188 #include <stdlib.h>
 189
 190 static inline _Unwind_Ptr
 191 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 192 {
 193   /* The GP is stored in R1.  */
 194   return _Unwind_GetGR (_C, 1);
 195 }
 196
 197 static inline _Unwind_Ptr
 198 _Unwind_GetTextRelBase (struct _Unwind_Context *_C)
 199 {
 200   abort ();
 201   return 0;
 202 }
 203
 204 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
 205 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
 206 #else
 207 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 208 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 209 #endif
 210
 211 /* @@@ Given an address, return the entry point of the function that
 212    contains it.  */
 213 extern void * _Unwind_FindEnclosingFunction (void *pc);
 214
 215 #ifdef __cplusplus
 216 }
 217 #endif
 218
 219 #endif  /* unwind.h */