libjava/include/dwarf2-signal.h

   1 // dwarf2-signal.h - Catch runtime signals and turn them into exceptions.
   2
   3 /* Copyright (C) 2000, 2001  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7    Use this file for a target for which the dwarf2 unwinder in libgcc
   8    can unwind through signal handlers.
   9
  10 This software is copyrighted work licensed under the terms of the
  11 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
  12 details.  */
  13
  14 #ifndef JAVA_SIGNAL_H
  15 #define JAVA_SIGNAL_H 1
  16
  17 #include <signal.h>
  18 #include <sys/syscall.h>
  19
  20 #define HANDLE_SEGV 1
  21 #undef HANDLE_FPE
  22
  23 #define SIGNAL_HANDLER(_name)   \
  24 static void _Jv_##_name (int, siginfo_t *, void *_p)
  25
  26 class java::lang::Throwable;
  27
  28 // Unwind the stack to the point at which the signal was generated and
  29 // then throw an exception.  With the dwarf2 unwinder we don't usually
  30 // need to do anything, with some minor exceptions.
  31
  32 #ifdef __alpha__
  33 #define MAKE_THROW_FRAME(_exception)                                    \
  34 do                                                                      \
  35 {                                                                       \
  36   /* Alpha either leaves PC pointing at a faulting instruction or the   \
  37    following instruction, depending on the signal.  SEGV always does    \
  38    the former, so we adjust the saved PC to point to the following      \
  39    instruction; this is what the handler in libgcc expects.  */         \
  40   struct sigcontext *_sc = (struct sigcontext *)_p;                     \
  41   _sc->sc_pc += 4;                                                      \
  42 }                                                                       \
  43 while (0)
  44 #else
  45 #define MAKE_THROW_FRAME(_exception)            \
  46 do                                              \
  47 {                                               \
  48   (void)_p;                                     \
  49 }                                               \
  50 while (0)
  51 #endif
  52
  53 #define INIT_SEGV                                               \
  54 do                                                              \
  55   {                                                             \
  56     nullp = new java::lang::NullPointerException ();            \
  57     struct sigaction act;                                       \
  58     act.sa_sigaction = _Jv_catch_segv;                          \
  59     sigemptyset (&act.sa_mask);                                 \
  60     act.sa_flags = SA_SIGINFO;                                  \
  61     syscall (SYS_sigaction, SIGSEGV, &act, NULL);               \
  62   }                                                             \
  63 while (0)
  64
  65 #define INIT_FPE                                                \
  66 do                                                              \
  67   {                                                             \
  68     arithexception = new java::lang::ArithmeticException        \
  69       (JvNewStringLatin1 ("/ by zero"));                        \
  70     struct sigaction act;                                       \
  71     act.sa_sigaction = _Jv_catch_fpe;                           \
  72     sigemptyset (&act.sa_mask);                                 \
  73     act.sa_flags = SA_SIGINFO;                                  \
  74     syscall (SYS_sigaction, SIGFPE, &act, NULL);                \
  75   }                                                             \
  76 while (0)
  77
  78 /* We use syscall(SYS_sigaction) in INIT_SEGV and INIT_FPE instead of
  79  * sigaction() because on some systems the pthreads wrappers for
  80  * signal handlers are not compiled with unwind information, so it's
  81  * not possible to unwind through them.  This is a problem that will
  82  * go away once all systems have pthreads libraries that are
  83  * compiled with full unwind info.  */
  84
  85 #endif /* JAVA_SIGNAL_H */