mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-28 21:49:33 +00:00
170 lines
3.9 KiB
C++
170 lines
3.9 KiB
C++
// natThreadLocal.cc - Native part of ThreadLocal class.
|
|
|
|
// Fast thread local storage for systems that support the __thread
|
|
// variable attribute.
|
|
|
|
/* Copyright (C) 2006 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. */
|
|
|
|
#include <config.h>
|
|
|
|
#include <stdlib.h>
|
|
|
|
#include <gcj/cni.h>
|
|
#include <jvm.h>
|
|
#include <java-threads.h>
|
|
|
|
#include <gnu/gcj/RawDataManaged.h>
|
|
#include <java/lang/ThreadLocal.h>
|
|
#include <java/lang/IllegalArgumentException.h>
|
|
#include <java/lang/IllegalThreadStateException.h>
|
|
#include <java/lang/InterruptedException.h>
|
|
#include <java/util/Map.h>
|
|
|
|
#include <jni.h>
|
|
|
|
/* We would like to have fast thread local variables that behave in
|
|
the same way as C and C++ thread local variables. This would mean
|
|
having an field attribute "thread" (like static, final, etc.).
|
|
However, this is not compatible with java semantics, which we wish
|
|
to support transparently. The problems we must overcome are:
|
|
|
|
* In Java, ThreadLocal variables are not statically allocated: they
|
|
are objects, created at runtime.
|
|
|
|
* Class ThreadLocal is not final and neither are its methods, so it
|
|
is possible to create a subclass of ThreadLocal that overrides
|
|
any method.
|
|
|
|
* __thread variables in DSOs are not visible to the garbage
|
|
collector, so we must ensure that we keep a copy of every thread
|
|
local variable somewhere on the heap.
|
|
|
|
* Once a ThreadLocal instance has been created and assigned to a
|
|
static field, that field may be reassigned to a different
|
|
ThreadLocal instance or null.
|
|
|
|
So, we can't simply replace get() and set() with accesses of a
|
|
__thread variable.
|
|
|
|
So, we create a pthread_key in each ThreadLocal object and use that
|
|
as a kind of "look-aside cache". When a ThreadLocal is set, we
|
|
also set the corresponding thread-specific value. When the
|
|
ThreadLocal is collected, we delete the key.
|
|
|
|
This scheme is biased towards efficiency when get() is called much
|
|
more frequently than set(). It is slightly internaler than the
|
|
all-Java solution using the underlying map in the set() case.
|
|
However, get() is very much more frequently invoked than set().
|
|
|
|
*/
|
|
|
|
|
|
#ifdef _POSIX_PTHREAD_SEMANTICS
|
|
|
|
class tls_t
|
|
{
|
|
public:
|
|
pthread_key_t key;
|
|
};
|
|
|
|
void
|
|
java::lang::ThreadLocal::constructNative (void)
|
|
{
|
|
tls_t *tls = (tls_t *)_Jv_Malloc (sizeof (tls_t));
|
|
if (pthread_key_create (&tls->key, NULL) == 0)
|
|
TLSPointer = (::gnu::gcj::RawData *)tls;
|
|
else
|
|
_Jv_Free (tls);
|
|
}
|
|
|
|
void
|
|
java::lang::ThreadLocal::set (::java::lang::Object *value)
|
|
{
|
|
if (TLSPointer != NULL)
|
|
{
|
|
tls_t* tls = (tls_t*)TLSPointer;
|
|
pthread_setspecific (tls->key, value);
|
|
}
|
|
|
|
internalSet (value);
|
|
}
|
|
|
|
::java::lang::Object *
|
|
java::lang::ThreadLocal::get (void)
|
|
{
|
|
if (TLSPointer == NULL)
|
|
return internalGet ();
|
|
|
|
tls_t* tls = (tls_t*)TLSPointer;
|
|
void *obj = pthread_getspecific(tls->key);
|
|
|
|
if (obj)
|
|
return (::java::lang::Object *)obj;
|
|
|
|
::java::lang::Object *value = internalGet ();
|
|
pthread_setspecific (tls->key, value);
|
|
|
|
return value;
|
|
}
|
|
|
|
void
|
|
java::lang::ThreadLocal::remove (void)
|
|
{
|
|
if (TLSPointer != NULL)
|
|
{
|
|
tls_t* tls = (tls_t*)TLSPointer;
|
|
pthread_setspecific (tls->key, NULL);
|
|
}
|
|
|
|
internalRemove ();
|
|
}
|
|
|
|
void
|
|
java::lang::ThreadLocal::finalize (void)
|
|
{
|
|
if (TLSPointer != NULL)
|
|
{
|
|
tls_t* tls = (tls_t*)TLSPointer;
|
|
pthread_key_delete (tls->key);
|
|
_Jv_Free (tls);
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
void
|
|
java::lang::ThreadLocal::constructNative (void)
|
|
{
|
|
}
|
|
|
|
void
|
|
java::lang::ThreadLocal::set (::java::lang::Object *value)
|
|
{
|
|
internalSet (value);
|
|
}
|
|
|
|
::java::lang::Object *
|
|
java::lang::ThreadLocal::get (void)
|
|
{
|
|
return internalGet ();
|
|
}
|
|
|
|
void
|
|
java::lang::ThreadLocal::remove (void)
|
|
{
|
|
internalRemove ();
|
|
}
|
|
|
|
void
|
|
java::lang::ThreadLocal::finalize (void)
|
|
{
|
|
}
|
|
|
|
#endif
|