libgcc/unwind-generic.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001-2018 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 3, 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    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 /* This is derived from the C++ ABI for IA-64.  Where we diverge
  26    for cross-architecture compatibility are noted with "@@@".  */
  27
  28 #ifndef _UNWIND_H
  29 #define _UNWIND_H
  30
  31 #if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
  32 /* Only for _GCC_specific_handler.  */
  33 #include <windows.h>
  34 #endif
  35
  36 #ifndef HIDE_EXPORTS
  37 #pragma GCC visibility push(default)
  38 #endif
  39
  40 #ifdef __cplusplus
  41 extern "C" {
  42 #endif
  43
  44 /* Level 1: Base ABI  */
  45
  46 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  47    inefficient for 32-bit and smaller machines.  */
  48 typedef unsigned _Unwind_Word __attribute__((__mode__(__unwind_word__)));
  49 typedef signed _Unwind_Sword __attribute__((__mode__(__unwind_word__)));
  50 #if defined(__ia64__) && defined(__hpux__)
  51 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  52 #else
  53 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  54 #endif
  55 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  56
  57 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  58    consumer of an exception.  We'll go along with this for now even on
  59    32-bit machines.  We'll need to provide some other option for
  60    16-bit machines and for machines with > 8 bits per byte.  */
  61 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  62
  63 /* The unwind interface uses reason codes in several contexts to
  64    identify the reasons for failures or other actions.  */
  65 typedef enum
  66 {
  67   _URC_NO_REASON = 0,
  68   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  69   _URC_FATAL_PHASE2_ERROR = 2,
  70   _URC_FATAL_PHASE1_ERROR = 3,
  71   _URC_NORMAL_STOP = 4,
  72   _URC_END_OF_STACK = 5,
  73   _URC_HANDLER_FOUND = 6,
  74   _URC_INSTALL_CONTEXT = 7,
  75   _URC_CONTINUE_UNWIND = 8
  76 } _Unwind_Reason_Code;
  77
  78
  79 /* The unwind interface uses a pointer to an exception header object
  80    as its representation of an exception being thrown. In general, the
  81    full representation of an exception object is language- and
  82    implementation-specific, but it will be prefixed by a header
  83    understood by the unwind interface.  */
  84
  85 struct _Unwind_Exception;
  86
  87 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  88                                               struct _Unwind_Exception *);
  89
  90 struct _Unwind_Exception
  91 {
  92   _Unwind_Exception_Class exception_class;
  93   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  94
  95 #if !defined (__USING_SJLJ_EXCEPTIONS__) && defined (__SEH__)
  96   _Unwind_Word private_[6];
  97 #else
  98   _Unwind_Word private_1;
  99   _Unwind_Word private_2;
 100 #endif
 101
 102   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
 103      Taking that literally does not make much sense generically.  Instead we
 104      provide the maximum alignment required by any type for the machine.  */
 105 } __attribute__((__aligned__));
 106
 107
 108 /* The ACTIONS argument to the personality routine is a bitwise OR of one
 109    or more of the following constants.  */
 110 typedef int _Unwind_Action;
 111
 112 #define _UA_SEARCH_PHASE        1
 113 #define _UA_CLEANUP_PHASE       2
 114 #define _UA_HANDLER_FRAME       4
 115 #define _UA_FORCE_UNWIND        8
 116 #define _UA_END_OF_STACK        16
 117
 118 /* The target can override this macro to define any back-end-specific
 119    attributes required for the lowest-level stack frame.  */
 120 #ifndef LIBGCC2_UNWIND_ATTRIBUTE
 121 #define LIBGCC2_UNWIND_ATTRIBUTE
 122 #endif
 123
 124 /* This is an opaque type used to refer to a system-specific data
 125    structure used by the system unwinder. This context is created and
 126    destroyed by the system, and passed to the personality routine
 127    during unwinding.  */
 128 struct _Unwind_Context;
 129
 130 /* Raise an exception, passing along the given exception object.  */
 131 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 132 _Unwind_RaiseException (struct _Unwind_Exception *);
 133
 134 /* Raise an exception for forced unwinding.  */
 135
 136 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 137      (int, _Unwind_Action, _Unwind_Exception_Class,
 138       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 139
 140 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 141 _Unwind_ForcedUnwind (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 142
 143 /* Helper to invoke the exception_cleanup routine.  */
 144 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 145
 146 /* Resume propagation of an existing exception.  This is used after
 147    e.g. executing cleanup code, and not to implement rethrowing.  */
 148 extern void LIBGCC2_UNWIND_ATTRIBUTE
 149 _Unwind_Resume (struct _Unwind_Exception *);
 150
 151 /* @@@ Resume propagation of a FORCE_UNWIND exception, or to rethrow
 152    a normal exception that was handled.  */
 153 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 154 _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
 155
 156 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 157    is called for every stack frame in the call chain, but no cleanup
 158    actions are performed.  */
 159 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 160      (struct _Unwind_Context *, void *);
 161
 162 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 163 _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 164
 165 /* These functions are used for communicating information about the unwind
 166    context (i.e. the unwind descriptors and the user register state) between
 167    the unwind library and the personality routine and landing pad.  Only
 168    selected registers may be manipulated.  */
 169
 170 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 171 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 172
 173 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 174 extern _Unwind_Ptr _Unwind_GetIPInfo (struct _Unwind_Context *, int *);
 175 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 176
 177 /* @@@ Retrieve the CFA of the given context.  */
 178 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 179
 180 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 181
 182 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 183
 184
 185 /* The personality routine is the function in the C++ (or other language)
 186    runtime library which serves as an interface between the system unwind
 187    library and language-specific exception handling semantics.  It is
 188    specific to the code fragment described by an unwind info block, and
 189    it is always referenced via the pointer in the unwind info block, and
 190    hence it has no ABI-specified name.
 191
 192    Note that this implies that two different C++ implementations can
 193    use different names, and have different contents in the language
 194    specific data area.  Moreover, that the language specific data
 195    area contains no version info because name of the function invoked
 196    provides more effective versioning by detecting at link time the
 197    lack of code to handle the different data format.  */
 198
 199 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 200      (int, _Unwind_Action, _Unwind_Exception_Class,
 201       struct _Unwind_Exception *, struct _Unwind_Context *);
 202
 203 /* @@@ The following alternate entry points are for setjmp/longjmp
 204    based unwinding.  */
 205
 206 struct SjLj_Function_Context;
 207 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 208 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 209
 210 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 211 _Unwind_SjLj_RaiseException (struct _Unwind_Exception *);
 212 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 213 _Unwind_SjLj_ForcedUnwind (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 214 extern void LIBGCC2_UNWIND_ATTRIBUTE
 215 _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 216 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 217 _Unwind_SjLj_Resume_or_Rethrow (struct _Unwind_Exception *);
 218
 219 /* @@@ The following provide access to the base addresses for text
 220    and data-relative addressing in the LDSA.  In order to stay link
 221    compatible with the standard ABI for IA-64, we inline these.  */
 222
 223 #ifdef __ia64__
 224 static inline _Unwind_Ptr
 225 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 226 {
 227   /* The GP is stored in R1.  */
 228   return _Unwind_GetGR (_C, 1);
 229 }
 230
 231 static inline _Unwind_Ptr
 232 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 233 {
 234   __builtin_abort ();
 235   return 0;
 236 }
 237
 238 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
 239 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
 240 #else
 241 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 242 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 243 #endif
 244
 245 /* @@@ Given an address, return the entry point of the function that
 246    contains it.  */
 247 extern void * _Unwind_FindEnclosingFunction (void *pc);
 248
 249 #ifndef __SIZEOF_LONG__
 250   #error "__SIZEOF_LONG__ macro not defined"
 251 #endif
 252
 253 #ifndef __SIZEOF_POINTER__
 254   #error "__SIZEOF_POINTER__ macro not defined"
 255 #endif
 256
 257
 258 /* leb128 type numbers have a potentially unlimited size.
 259    The target of the following definitions of _sleb128_t and _uleb128_t
 260    is to have efficient data types large enough to hold the leb128 type
 261    numbers used in the unwind code.
 262    Mostly these types will simply be defined to long and unsigned long
 263    except when a unsigned long data type on the target machine is not
 264    capable of storing a pointer.  */
 265
 266 #if __SIZEOF_LONG__ >= __SIZEOF_POINTER__
 267   typedef long _sleb128_t;
 268   typedef unsigned long _uleb128_t;
 269 #elif __SIZEOF_LONG_LONG__ >= __SIZEOF_POINTER__
 270   typedef long long _sleb128_t;
 271   typedef unsigned long long _uleb128_t;
 272 #else
 273 # error "What type shall we use for _sleb128_t?"
 274 #endif
 275
 276 #if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
 277 /* Handles the mapping from SEH to GCC interfaces.  */
 278 EXCEPTION_DISPOSITION _GCC_specific_handler (PEXCEPTION_RECORD, void *,
 279                                              PCONTEXT, PDISPATCHER_CONTEXT,
 280                                              _Unwind_Personality_Fn);
 281 #endif
 282
 283 #ifdef __cplusplus
 284 }
 285 #endif
 286
 287 #ifndef HIDE_EXPORTS
 288 #pragma GCC visibility pop
 289 #endif
 290
 291 /* Additional actions to unwind number of stack frames.  */
 292 #define _Unwind_Frames_Extra(frames)
 293
 294 /* Increment frame count.  */
 295 #define _Unwind_Frames_Increment(context, frames) frames++
 296
 297 #endif /* unwind.h */