mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-30 18:25:35 +08:00
ba75520fff
2001-07-13 Alexandre Petit-Bianco <apbianco@redhat.com> * include/i386-signal.h (HANDLE_DIVIDE_OVERFLOW): Removed unused local `_ebp.' (http://gcc.gnu.org/ml/java-patches/2001-q3/msg00070.html ) From-SVN: r44093
142 lines
4.4 KiB
C
142 lines
4.4 KiB
C
// i386-signal.h - Catch runtime signals and turn them into exceptions.
|
|
|
|
/* Copyright (C) 1998, 1999, 2001 Free Software Foundation
|
|
|
|
This file is part of libgcj.
|
|
|
|
This software is copyrighted work licensed under the terms of the
|
|
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
|
|
details. */
|
|
|
|
/* This technique should work for all i386 based Unices which conform
|
|
* to iBCS2. This includes all versions of Linux more recent than 1.3
|
|
*/
|
|
|
|
|
|
#ifndef JAVA_SIGNAL_H
|
|
#define JAVA_SIGNAL_H 1
|
|
|
|
#include <signal.h>
|
|
#include <sys/syscall.h>
|
|
|
|
#define HANDLE_SEGV 1
|
|
#define HANDLE_FPE 1
|
|
|
|
#define SIGNAL_HANDLER(_name) \
|
|
static void _name (int _dummy)
|
|
|
|
#define MAKE_THROW_FRAME(_exception) \
|
|
do \
|
|
{ \
|
|
void **_p = (void **)&_dummy; \
|
|
struct sigcontext_struct *_regs = (struct sigcontext_struct *)++_p; \
|
|
\
|
|
/* Advance the program counter so that it is after the start of the \
|
|
instruction: the x86 exception handler expects \
|
|
the PC to point to the instruction after a call. */ \
|
|
_regs->eip += 2; \
|
|
\
|
|
} \
|
|
while (0)
|
|
|
|
#define HANDLE_DIVIDE_OVERFLOW \
|
|
do \
|
|
{ \
|
|
void **_p = (void **)&_dummy; \
|
|
struct sigcontext_struct *_regs = (struct sigcontext_struct *)++_p; \
|
|
\
|
|
register unsigned char *_eip = (unsigned char *)_regs->eip; \
|
|
\
|
|
/* According to the JVM spec, "if the dividend is the negative \
|
|
* integer of the smallest magnitude and the divisor is -1, then \
|
|
* overflow occurs and the result is equal to the dividend. Despite \
|
|
* the overflow, no exception occurs". \
|
|
\
|
|
* We handle this by inspecting the instruction which generated the \
|
|
* signal and advancing eip to point to the following instruction. \
|
|
* As the instructions are variable length it is necessary to do a \
|
|
* little calculation to figure out where the following instruction \
|
|
* actually is. \
|
|
\
|
|
*/ \
|
|
\
|
|
if (_eip[0] == 0xf7) \
|
|
{ \
|
|
unsigned char _modrm = _eip[1]; \
|
|
\
|
|
if (_regs->eax == 0x80000000 \
|
|
&& ((_modrm >> 3) & 7) == 7) /* Signed divide */ \
|
|
{ \
|
|
_regs->edx = 0; /* the remainder is zero */ \
|
|
switch (_modrm >> 6) \
|
|
{ \
|
|
case 0: \
|
|
if ((_modrm & 7) == 5) \
|
|
_eip += 4; \
|
|
break; \
|
|
case 1: \
|
|
_eip += 1; \
|
|
break; \
|
|
case 2: \
|
|
_eip += 4; \
|
|
break; \
|
|
case 3: \
|
|
break; \
|
|
} \
|
|
_eip += 2; \
|
|
_regs->eip = (unsigned long)_eip; \
|
|
return; \
|
|
} \
|
|
else \
|
|
{ \
|
|
/* Advance the program counter so that it is after the start \
|
|
of the instruction: this is because the x86 exception \
|
|
handler expects the PC to point to the instruction after a \
|
|
call. */ \
|
|
_regs->eip += 2; \
|
|
} \
|
|
} \
|
|
} \
|
|
while (0)
|
|
|
|
#define INIT_SEGV \
|
|
do \
|
|
{ \
|
|
nullp = new java::lang::NullPointerException (); \
|
|
struct sigaction act; \
|
|
act.sa_handler = catch_segv; \
|
|
sigemptyset (&act.sa_mask); \
|
|
act.sa_flags = 0; \
|
|
syscall (SYS_sigaction, SIGSEGV, &act, NULL); \
|
|
} \
|
|
while (0)
|
|
|
|
#define INIT_FPE \
|
|
do \
|
|
{ \
|
|
arithexception = new java::lang::ArithmeticException \
|
|
(JvNewStringLatin1 ("/ by zero")); \
|
|
struct sigaction act; \
|
|
act.sa_handler = catch_fpe; \
|
|
sigemptyset (&act.sa_mask); \
|
|
act.sa_flags = 0; \
|
|
syscall (SYS_sigaction, SIGFPE, &act, NULL); \
|
|
} \
|
|
while (0)
|
|
|
|
/* You might wonder why we use syscall(SYS_sigaction) in INIT_FPE
|
|
* instead of the standard sigaction(). This is necessary because of
|
|
* the shenanigans above where we increment the PC saved in the
|
|
* context and then return. This trick will only work when we are
|
|
* called _directly_ by the kernel, because linuxthreads wraps signal
|
|
* handlers and its wrappers do not copy the sigcontext struct back
|
|
* when returning from a signal handler. If we return from our divide
|
|
* handler to a linuxthreads wrapper, we will lose the PC adjustment
|
|
* we made and return to the faulting instruction again. Using
|
|
* syscall(SYS_sigaction) causes our handler to be called directly by
|
|
* the kernel, bypassing any wrappers. This is a kludge, and a future
|
|
* version of this handler will do something better. */
|
|
|
|
#endif /* JAVA_SIGNAL_H */
|
|
|