gcc/unwind-libunwind.c

   1 /* Subroutines needed for unwinding stack frames via the libunwind API.
   2    Copyright (C) 2002
   3    Free Software Foundation, Inc.
   4    Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
   5
   6    This file is part of GNU CC.
   7
   8    GNU CC is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    GNU CC is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with GNU CC; see the file COPYING.  If not, write to
  20    the Free Software Foundation, 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 /* As a special exception, if you link this library with other files,
  24    some of which are compiled with GCC, to produce an executable,
  25    this library does not by itself cause the resulting executable
  26    to be covered by the GNU General Public License.
  27    This exception does not however invalidate any other reasons why
  28    the executable file might be covered by the GNU General Public License.  */
  29
  30 #include "tconfig.h"
  31 #include "tsystem.h"
  32 #include "unwind.h"
  33
  34 #ifndef __USING_SJLJ_EXCEPTIONS__
  35
  36 #define UNW_LOCAL_ONLY
  37
  38 #include <libunwind.h>
  39
  40 typedef struct {
  41   _Unwind_Personality_Fn personality;
  42 } _Unwind_FrameState;
  43
  44 struct _Unwind_Context {
  45   unw_cursor_t cursor;
  46 };
  47
  48 \f
  49 /* First come the helper-routines that are needed by unwind.inc.  */
  50
  51 static _Unwind_Reason_Code
  52 uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
  53 {
  54   unw_word_t handler;
  55
  56   if (unw_step (&context->cursor) <= 0)
  57     return _URC_END_OF_STACK;
  58
  59   unw_get_reg (&context->cursor, UNW_REG_HANDLER, &handler);
  60   fs->personality = (_Unwind_Personality_Fn) handler;
  61
  62   return _URC_NO_REASON;
  63 }
  64
  65 #define uw_update_context(context,fs)   do { ; } while (0)
  66
  67 static inline _Unwind_Ptr
  68 uw_identify_context (struct _Unwind_Context *context)
  69 {
  70   unw_word_t ip;
  71   unw_get_reg (&context->cursor, UNW_REG_IP, &ip);
  72   return (_Unwind_Ptr) ip;
  73 }
  74
  75 #define uw_init_context(context)                \
  76 do                                              \
  77   {                                             \
  78     unw_context_t uc;                           \
  79     unw_getcontext (&uc);                       \
  80     unw_init_local (&(context)->cursor, &uc);   \
  81   }                                             \
  82 while (0)
  83
  84 static inline void __attribute__ ((noreturn))
  85 uw_install_context (struct _Unwind_Context *current __attribute__ ((unused)),
  86                     struct _Unwind_Context *target)
  87 {
  88   unw_resume (&(target)->cursor);
  89   abort ();
  90 }
  91
  92 \f
  93 /* Now come the helper-routines which may be called from an exception
  94    handler.  The interface for these routines are defined by the C++
  95    ABI.  See: http://www.codesourcery.com/cxx-abi/abi-eh.html */
  96
  97 _Unwind_Word
  98 _Unwind_GetGR (struct _Unwind_Context *context, int index)
  99 {
 100   unw_word_t ret;
 101
 102   /* Note: here we depend on the fact that general registers are
 103      expected to start with register number 0!  */
 104   unw_get_reg (&context->cursor, index, &ret);
 105   return ret;
 106 }
 107
 108 /* Overwrite the saved value for register REG in CONTEXT with VAL.  */
 109
 110 void
 111 _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
 112 {
 113   /* Note: here we depend on the fact that general registers are
 114      expected to start with register number 0!  */
 115   unw_set_reg (&context->cursor, index, val);
 116 }
 117
 118 /* Retrieve the return address for CONTEXT.  */
 119
 120 inline _Unwind_Ptr
 121 _Unwind_GetIP (struct _Unwind_Context *context)
 122 {
 123   unw_word_t ret;
 124
 125   unw_get_reg (&context->cursor, UNW_REG_IP, &ret);
 126   return ret;
 127 }
 128
 129 /* Overwrite the return address for CONTEXT with VAL.  */
 130
 131 inline void
 132 _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
 133 {
 134   unw_set_reg (&context->cursor, UNW_REG_IP, val);
 135 }
 136
 137 void *
 138 _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
 139 {
 140   unw_word_t ret;
 141
 142   unw_get_reg (&context->cursor, UNW_REG_LSDA, &ret);
 143   return (void *) ret;
 144 }
 145
 146 _Unwind_Ptr
 147 _Unwind_GetRegionStart (struct _Unwind_Context *context)
 148 {
 149   unw_word_t ret;
 150
 151   unw_get_reg (&context->cursor, UNW_REG_PROC_START, &ret);
 152   return (_Unwind_Ptr) ret;
 153 }
 154
 155 #include "unwind.inc"
 156
 157 #endif /* !__USING_SJLJ_EXCEPTIONS__ */