gcc/libjava/exception.cc

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// Functions for Exception Support for Java.
/* Copyright (C) 1998, 1999 Cygnus Solutions
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. */
#include <config.h>
#include "exception"
#include <stddef.h>
#include <stdlib.h>
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#include <java/lang/Class.h>
#include <java/lang/NullPointerException.h>
#include <gcj/cni.h>
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#include <jvm.h>
// eh-common.h needs gansidecl.h.
#include "gansidecl.h"
#include "eh-common.h"
typedef struct {
__eh_info eh_info;
void *value;
} java_eh_info;
/* Language-specific EH info pointer, throw routine, and language/version
info routines. All defined in libgcc2. */
extern "C" java_eh_info **__get_eh_info ();
extern "C" void __throw () __attribute__ ((__noreturn__));
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extern "C" void __sjthrow () __attribute__ ((__noreturn__));
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extern "C" short __get_eh_table_version (void *table);
extern "C" short __get_eh_table_language (void *table);
extern "C" void *
_Jv_type_matcher (java_eh_info *info, void* match_info,
void *exception_table)
{
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#ifndef SJLJ_EXCEPTIONS
/* No exception table implies the old style mechanism, so don't check. */
if (exception_table != NULL
&& __get_eh_table_language (exception_table) != EH_LANG_Java)
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return NULL;
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#endif
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/* we don't worry about version info yet, there is only one version! */
if (match_info != NULL)
{
// The match_info is either a (java::lang::Class*) or
// match_info is one more than a (Utf8Const*).
if (sizeof(void*) != sizeof(size_t))
abort();
size_t mi = (size_t) match_info;
if ((mi & 1) != 0)
match_info = _Jv_FindClass ((Utf8Const*) (mi - 1), NULL);
if (! _Jv_IsInstanceOf ((jobject) info->value, (jclass) match_info))
return NULL;
}
return info->value;
}
/* Compiler hook to return a pointer to java exception object. The value
is cleared, so if the exception needs to be rethrown, it should be set
again */
extern "C" void *
_Jv_exception_info (void)
{
java_eh_info *info = *(__get_eh_info ());
void *ptr;
if (info == NULL)
abort ();
ptr = info->value;
/* clear the value so another throw is an error */
info->value = NULL;
return ptr;
}
/* Allocate an exception info structure for java. Called the first time
an exception is thrown. */
extern "C" void
_Jv_eh_alloc ()
{
/* FIXME: we should use _Jv_AllocBytes here. However, libgcc2
apparently can sometimes free() this value itself. */
java_eh_info *p = (java_eh_info *) malloc (sizeof (java_eh_info));
if (p == 0)
terminate ();
p->value = 0;
java_eh_info ** info_ptr = __get_eh_info ();
/* There should NOT be an exception info pointer already. */
if (*info_ptr != NULL)
abort ();
*info_ptr = p;
}
/* Deallocate the current exception info structure. Called at shutdown time. */
extern "C" void
_Jv_eh_free ()
{
java_eh_info ** info_ptr = __get_eh_info ();
if (*info_ptr == NULL)
abort ();
/* FIXME: ideally we should just let the GC handle this. */
free (*info_ptr);
*info_ptr = NULL;
}
/* Initialize an __eh_info structure with this libraries matching info. */
extern "C" void
_Jv_setup_eh_info (__eh_info *)
{
}
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/* Perform a throw, Java style. Throw will unwind through this call,
so there better not be any handlers or exception thrown here. */
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extern "C" void
_Jv_Throw (void *value)
{
if (value == NULL)
value = (void *) new java::lang::NullPointerException ();
java_eh_info *ehinfo = *(__get_eh_info ());
if (ehinfo == NULL)
{
_Jv_eh_alloc ();
ehinfo = *(__get_eh_info ());
}
ehinfo->eh_info.match_function = (__eh_matcher) _Jv_type_matcher;
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ehinfo->eh_info.language = EH_LANG_Java;
ehinfo->eh_info.version = 1;
ehinfo->value = value;
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/* We're happy with setjmp/longjmp exceptions or region-based
exception handlers: entry points are provided here for both. */
#ifdef SJLJ_EXCEPTIONS
__sjthrow ();
#else
__throw ();
#endif
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}