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      1 /* Exception handling and frame unwind runtime interface routines.
      2    Copyright (C) 2001-2014 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 #include <stdlib.h>
    225 
    226 static inline _Unwind_Ptr
    227 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
    228 {
    229   /* The GP is stored in R1.  */
    230   return _Unwind_GetGR (_C, 1);
    231 }
    232 
    233 static inline _Unwind_Ptr
    234 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
    235 {
    236   abort ();
    237   return 0;
    238 }
    239 
    240 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
    241 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
    242 #else
    243 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
    244 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
    245 #endif
    246 
    247 /* @@@ Given an address, return the entry point of the function that
    248    contains it.  */
    249 extern void * _Unwind_FindEnclosingFunction (void *pc);
    250 
    251 #ifndef __SIZEOF_LONG__
    252   #error "__SIZEOF_LONG__ macro not defined"
    253 #endif
    254 
    255 #ifndef __SIZEOF_POINTER__
    256   #error "__SIZEOF_POINTER__ macro not defined"
    257 #endif
    258 
    259 
    260 /* leb128 type numbers have a potentially unlimited size.
    261    The target of the following definitions of _sleb128_t and _uleb128_t
    262    is to have efficient data types large enough to hold the leb128 type
    263    numbers used in the unwind code.
    264    Mostly these types will simply be defined to long and unsigned long
    265    except when a unsigned long data type on the target machine is not
    266    capable of storing a pointer.  */
    267 
    268 #if __SIZEOF_LONG__ >= __SIZEOF_POINTER__
    269   typedef long _sleb128_t;
    270   typedef unsigned long _uleb128_t;
    271 #elif __SIZEOF_LONG_LONG__ >= __SIZEOF_POINTER__
    272   typedef long long _sleb128_t;
    273   typedef unsigned long long _uleb128_t;
    274 #else
    275 # error "What type shall we use for _sleb128_t?"
    276 #endif
    277 
    278 #if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
    279 /* Handles the mapping from SEH to GCC interfaces.  */
    280 EXCEPTION_DISPOSITION _GCC_specific_handler (PEXCEPTION_RECORD, void *,
    281 					     PCONTEXT, PDISPATCHER_CONTEXT,
    282 					     _Unwind_Personality_Fn);
    283 #endif
    284 
    285 #ifdef __cplusplus
    286 }
    287 #endif
    288 
    289 #ifndef HIDE_EXPORTS
    290 #pragma GCC visibility pop
    291 #endif
    292 
    293 #endif /* unwind.h */
    294