OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

x86_64-signal.h (HANDLE_DIVIDE_OVERFLOW): New.

Browse Source 
2006-04-10  Andrew Haley  <aph@redhat.com>

        * include/x86_64-signal.h (HANDLE_DIVIDE_OVERFLOW): New.
        (SIGNAL_HANDLER): Mark arg as unused.
        * configure.host (x86_64-* DIVIDESPEC): Use
        fno-use-divide-subroutine.

From-SVN: r112827
This commit is contained in:
Andrew Haley 2006-04-10 16:01:23 +00:00 committed by Andrew Haley
parent 1f3d30ed89
commit e92857a103
3 changed files with 112 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
libjava/ChangeLog
View File

@ -1,3 +1,10 @@
2006-04-10 Andrew Haley <aph@redhat.com>
* include/x86_64-signal.h (HANDLE_DIVIDE_OVERFLOW): New.
(SIGNAL_HANDLER): Mark arg as unused.
* configure.host (x86_64-* DIVIDESPEC): Use
fno-use-divide-subroutine.
2006-04-07 Andrew Haley <aph@redhat.com>
* java/net/InetAddress.java: Throw an UnknownHostException if

2
libjava/configure.host
View File

@ -115,7 +115,7 @@ case "${host}" in
libgcj_flags="${libgcj_flags} -fomit-frame-pointer"
libgcj_cxxflags=
libgcj_cflags=
DIVIDESPEC=-f%{m32:no-}use-divide-subroutine
DIVIDESPEC=-fno-use-divide-subroutine
enable_hash_synchronization_default=yes
slow_pthread_self=yes
libgcj_interpreter=yes

112
libjava/include/x86_64-signal.h
View File

@ -19,9 +19,88 @@ details. */
#include <sys/syscall.h>
#define HANDLE_SEGV 1
#define HANDLE_FPE 1
#define SIGNAL_HANDLER(_name) \
static void _Jv_##_name (int, siginfo_t *, void *_p)
#define SIGNAL_HANDLER(_name) \
static void _Jv_##_name (int, siginfo_t *, \
void *_p __attribute__ ((__unused__)))
#define HANDLE_DIVIDE_OVERFLOW \
do \
{ \
struct ucontext *_uc = (struct ucontext *)_p; \
volatile struct sigcontext *_sc = (struct sigcontext *) &_uc->uc_mcontext; \
\
register unsigned char *_rip = (unsigned char *)_sc->rip; \
\
/* According to the JVM spec, "if the dividend is the negative \
* integer of largest possible magnitude for the type 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 ip 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. \
\
*/ \
\
bool _is_64_bit = false; \
\
if ((_rip[0] & 0xf0) == 0x40) /* REX byte present. */ \
{ \
unsigned char _rex = _rip[0] & 0x0f; \
_is_64_bit = (_rex & 0x08) != 0; \
_rip++; \
} \
\
/* Detect a signed division of Integer.MIN_VALUE or Long.MIN_VALUE. */ \
if (_rip[0] == 0xf7) \
{ \
bool _min_value_dividend = false; \
unsigned char _modrm = _rip[1]; \
\
if (((_modrm >> 3) & 7) == 7) \
{ \
if (_is_64_bit) \
_min_value_dividend = (_sc->rax == 0x8000000000000000L); \
else \
_min_value_dividend = ((_sc->rax & 0xffffffff) == 0x80000000); \
} \
\
if (_min_value_dividend) \
{ \
unsigned char _rm = _modrm & 7; \
_sc->rdx = 0; /* the remainder is zero */ \
switch (_modrm >> 6) \
{ \
case 0: /* register indirect */ \
if (_rm == 5) /* 32-bit displacement */ \
_rip += 4; \
if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
_rip += 1; \
break; \
case 1: /* register indirect + 8-bit displacement */ \
_rip += 1; \
if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
_rip += 1; \
break; \
case 2: /* register indirect + 32-bit displacement */ \
_rip += 4; \
if (_rm == 4) /* A SIB byte follows the ModR/M byte */ \
_rip += 1; \
break; \
case 3: \
break; \
} \
_rip += 2; \
_sc->rip = (unsigned long)_rip; \
return; \
} \
} \
} \
while (0)
extern "C"
{
@ -65,12 +144,29 @@ do \
} \
while (0)
/* We use syscall(SYS_rt_sigaction) in INIT_SEGV instead of
* sigaction() because on some systems the pthreads wrappers for
* signal handlers are not compiled with unwind information, so it's
* not possible to unwind through them. This is a problem that will
* go away if all systems ever have pthreads libraries that are
* compiled with unwind info. */
#define INIT_FPE \
do \
{ \
struct kernel_sigaction act; \
act.k_sa_sigaction = _Jv_catch_fpe; \
sigemptyset (&act.k_sa_mask); \
act.k_sa_flags = SA_SIGINFO|0x4000000; \
act.k_sa_restorer = restore_rt; \
syscall (SYS_rt_sigaction, SIGFPE, &act, NULL, _NSIG / 8); \
} \
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. */
#endif /* JAVA_SIGNAL_H */