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80be8f05f1
1999-07-07 Andrew Haley <aph@cygnus.com>
* include/i386-signal.h (MAKE_THROW_FRAME): Advance EIP by two
bytes to make it point after the instruction where the trap
occurred.
(HANDLE_DIVIDE_OVERFLOW): Ditto.
From-SVN: r27989
149 lines
4.5 KiB
C
149 lines
4.5 KiB
C
// i386-signal.h - Catch runtime signals and turn them into exceptions.
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/* Copyright (C) 1998, 1999 Cygnus Solutions
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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/* This technique should work for all i386 based Unices which conform
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* to iBCS2. This includes all versions of Linux more recent than 1.3
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*/
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#ifndef JAVA_SIGNAL_H
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#define JAVA_SIGNAL_H 1
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#include <signal.h>
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#define HANDLE_SEGV 1
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#define HANDLE_FPE 1
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#define SIGNAL_HANDLER(_name) \
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static void _name (int _dummy)
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#define MAKE_THROW_FRAME \
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do \
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{ \
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void **_p = (void **)&_dummy; \
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struct sigcontext_struct *_regs = (struct sigcontext_struct *)++_p; \
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\
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register unsigned long _ebp = _regs->ebp; \
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register unsigned char *_eip = (unsigned char *)_regs->eip; \
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\
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/* Advance the program counter so that it is after the start of the \
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instruction: the x86 exception handler expects \
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the PC to point to the instruction after a call. */ \
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_eip += 2; \
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\
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asm volatile ("mov %0, (%%ebp); mov %1, 4(%%ebp)" \
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: : "r"(_ebp), "r"(_eip)); \
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} \
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while (0)
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#define HANDLE_DIVIDE_OVERFLOW \
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do \
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{ \
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void **_p = (void **)&_dummy; \
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struct sigcontext_struct *_regs = (struct sigcontext_struct *)++_p; \
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\
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register unsigned long *_ebp = (unsigned long *)_regs->ebp; \
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register unsigned char *_eip = (unsigned char *)_regs->eip; \
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\
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/* According to the JVM spec, "if the dividend is the negative \
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* integer of the smallest magnitude and the divisor is -1, then \
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* overflow occurs and the result is equal to the dividend. Despite \
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* the overflow, no exception occurs". \
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\
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* We handle this by inspecting the instruction which generated the \
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* signal and advancing eip to point to the following instruction. \
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* As the instructions are variable length it is necessary to do a \
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* little calculation to figure out where the following instruction \
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* actually is. \
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\
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*/ \
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\
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if (_eip[0] == 0xf7) \
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{ \
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unsigned char _modrm = _eip[1]; \
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\
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if (_regs->eax == 0x80000000 \
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&& ((_modrm >> 3) & 7) == 7) /* Signed divide */ \
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{ \
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_regs->edx = 0; /* the remainder is zero */ \
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switch (_modrm >> 6) \
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{ \
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case 0: \
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if ((_modrm & 7) == 5) \
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_eip += 4; \
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break; \
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case 1: \
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_eip += 1; \
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break; \
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case 2: \
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_eip += 4; \
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break; \
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case 3: \
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break; \
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} \
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_eip += 2; \
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_regs->eip = (unsigned long)_eip; \
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return; \
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} \
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else if (((_modrm >> 3) & 7) == 6) /* Unsigned divide */ \
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{ \
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/* We assume that unsigned divisions are in library code, so \
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* we throw one level down the stack, which was hopefully \
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* the place that called the library routine. This will \
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* break if the library is ever compiled with \
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* -fomit-frame-pointer, but at least this way we've got a \
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* good chance of finding the exception handler. */ \
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\
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_eip = (unsigned char *)_ebp[1]; \
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_ebp = (unsigned long *)_ebp[0]; \
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} \
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else \
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{ \
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/* Advance the program counter so that it is after the start \
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of the instruction: this is because the x86 exception \
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handler expects the PC to point to the instruction after a \
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call. */ \
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_eip += 2; \
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} \
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} \
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\
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asm volatile ("mov %0, (%%ebp); mov %1, 4(%%ebp)" \
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: : "r"(_ebp), "r"(_eip)); \
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} \
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while (0)
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#define INIT_SEGV \
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do \
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{ \
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nullp = new java::lang::NullPointerException (); \
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struct sigaction act; \
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act.sa_handler = catch_segv; \
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sigemptyset (&act.sa_mask); \
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act.sa_flags = 0; \
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__sigaction (SIGSEGV, &act, NULL); \
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} \
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while (0)
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#define INIT_FPE \
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do \
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{ \
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arithexception = new java::lang::ArithmeticException \
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(JvNewStringLatin1 ("/ by zero")); \
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struct sigaction act; \
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act.sa_handler = catch_fpe; \
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sigemptyset (&act.sa_mask); \
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act.sa_flags = 0; \
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__sigaction (SIGFPE, &act, NULL); \
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} \
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while (0)
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#endif /* JAVA_SIGNAL_H */
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