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 GCC.
   7
   8    GCC 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    GCC 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 GCC; 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_proc_info_t pi;
  55
  56   if (unw_step (&context->cursor) <= 0)
  57     return _URC_END_OF_STACK;
  58
  59   unw_get_proc_info(&context->cursor, &pi);
  60   fs->personality = (_Unwind_Personality_Fn) pi.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 /* Get the value of the CFA as saved in CONTEXT.  */
 109
 110 _Unwind_Word
 111 _Unwind_GetCFA (struct _Unwind_Context *context)
 112 {
 113   /* ??? Is there any way to get this information?  */
 114   return NULL;
 115 }
 116
 117 /* Overwrite the saved value for register REG in CONTEXT with VAL.  */
 118
 119 void
 120 _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
 121 {
 122   /* Note: here we depend on the fact that general registers are
 123      expected to start with register number 0!  */
 124   unw_set_reg (&context->cursor, index, val);
 125 }
 126
 127 /* Retrieve the return address for CONTEXT.  */
 128
 129 inline _Unwind_Ptr
 130 _Unwind_GetIP (struct _Unwind_Context *context)
 131 {
 132   unw_word_t ret;
 133
 134   unw_get_reg (&context->cursor, UNW_REG_IP, &ret);
 135   return ret;
 136 }
 137
 138 /* Overwrite the return address for CONTEXT with VAL.  */
 139
 140 inline void
 141 _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
 142 {
 143   unw_set_reg (&context->cursor, UNW_REG_IP, val);
 144 }
 145
 146 void *
 147 _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
 148 {
 149   unw_proc_info_t pi;
 150
 151   unw_get_proc_info(&context->cursor, &pi);
 152   return (void *) pi.lsda;
 153 }
 154
 155 _Unwind_Ptr
 156 _Unwind_GetRegionStart (struct _Unwind_Context *context)
 157 {
 158   unw_proc_info_t pi;
 159
 160   unw_get_proc_info(&context->cursor, &pi);
 161   return (_Unwind_Ptr) pi.start_ip;
 162 }
 163
 164 #include "unwind.inc"
 165
 166 #endif /* !__USING_SJLJ_EXCEPTIONS__ */