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
  45 #elif defined(__ia64__)
  46
  47 #define MAKE_THROW_FRAME(_exception)                                    \
  48 do                                                                      \
  49 {                                                                       \
  50   /* IA-64 either leaves PC pointing at a faulting instruction or the   \
  51    following instruction, depending on the signal.  SEGV always does    \
  52    the former, so we adjust the saved PC to point to the following      \
  53    instruction; this is what the handler in libgcc expects.  */         \
  54   /* Note that we are lying to the unwinder here, which expects the     \
  55    faulting pc, not pc+1.  But we claim the unwind information can't    \
  56    be changed by such a ld or st instruction, so it doesn't matter. */  \
  57   struct sigcontext *_sc = (struct sigcontext *)_p;                     \
  58   _sc->sc_ip++;                                                         \
  59 }                                                                       \
  60 while (0)
  61 #else
  62 #define MAKE_THROW_FRAME(_exception)            \
  63 do                                              \
  64 {                                               \
  65   (void)_p;                                     \
  66 }                                               \
  67 while (0)
  68 #endif
  69
  70 #ifndef __ia64__
  71 #define INIT_SEGV                                               \
  72 do                                                              \
  73   {                                                             \
  74     nullp = new java::lang::NullPointerException ();            \
  75     struct sigaction act;                                       \
  76     act.sa_sigaction = _Jv_catch_segv;                          \
  77     sigemptyset (&act.sa_mask);                                 \
  78     act.sa_flags = SA_SIGINFO;                                  \
  79     syscall (SYS_sigaction, SIGSEGV, &act, NULL);               \
  80   }                                                             \
  81 while (0)
  82
  83 #define INIT_FPE                                                \
  84 do                                                              \
  85   {                                                             \
  86     arithexception = new java::lang::ArithmeticException        \
  87       (JvNewStringLatin1 ("/ by zero"));                        \
  88     struct sigaction act;                                       \
  89     act.sa_sigaction = _Jv_catch_fpe;                           \
  90     sigemptyset (&act.sa_mask);                                 \
  91     act.sa_flags = SA_SIGINFO;                                  \
  92     syscall (SYS_sigaction, SIGFPE, &act, NULL);                \
  93   }                                                             \
  94 while (0)
  95
  96 /* We use syscall(SYS_sigaction) in INIT_SEGV and INIT_FPE instead of
  97  * sigaction() because on some systems the pthreads wrappers for
  98  * signal handlers are not compiled with unwind information, so it's
  99  * not possible to unwind through them.  This is a problem that will
 100  * go away once all systems have pthreads libraries that are
 101  * compiled with full unwind info.  */
 102
 103 #else  /* __ia64__ */
 104
 105 // FIXME: We shouldn't be using libc_sigaction here, since it should
 106 // be glibc private.  But using syscall here would mean translating to
 107 // the kernel's struct sigaction and argument sequence, which we
 108 // shouldn't either.  The right solution is to call sigaction and to
 109 // make sure that we can unwind correctly through the pthread signal
 110 // wrapper.
 111 extern "C" int __libc_sigaction (int __sig,
 112                       __const struct sigaction *__restrict __act,
 113                       struct sigaction *__restrict __oact) throw ();
 114
 115 #define INIT_SEGV                                               \
 116 do                                                              \
 117   {                                                             \
 118     nullp = new java::lang::NullPointerException ();            \
 119     struct sigaction act;                                       \
 120     act.sa_sigaction = _Jv_catch_segv;                          \
 121     sigemptyset (&act.sa_mask);                                 \
 122     act.sa_flags = SA_SIGINFO;                                  \
 123     __libc_sigaction (SIGSEGV, &act, NULL);                     \
 124   }                                                             \
 125 while (0)
 126
 127 #define INIT_FPE                                                \
 128 do                                                              \
 129   {                                                             \
 130     arithexception = new java::lang::ArithmeticException        \
 131       (JvNewStringLatin1 ("/ by zero"));                        \
 132     struct sigaction act;                                       \
 133     act.sa_sigaction = _Jv_catch_fpe;                           \
 134     sigemptyset (&act.sa_mask);                                 \
 135     act.sa_flags = SA_SIGINFO;                                  \
 136     __libc_sigaction (SIGFPE, &act, NULL);                      \
 137   }                                                             \
 138 while (0)
 139 #endif /* __ia64__ */
 140 #endif /* JAVA_SIGNAL_H */