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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "jni.h"
#include <iostream>
#include "art_method.h"
#include "base/casts.h"
#include "class_linker.h"
#include "jit/jit.h"
#include "linear_alloc.h"
#include "nativehelper/ScopedUtfChars.h"
#include "runtime.h"
#include "scoped_thread_state_change-inl.h"
#include "thread-current-inl.h"
namespace art {
namespace {
class FindPointerAllocatorVisitor : public AllocatorVisitor {
public:
explicit FindPointerAllocatorVisitor(void* ptr) : is_found(false), ptr_(ptr) {}
bool Visit(LinearAlloc* alloc)
REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_) override {
is_found = alloc->Contains(ptr_);
return !is_found;
}
bool is_found;
private:
void* ptr_;
};
extern "C" JNIEXPORT jlong JNICALL Java_Main_getArtMethod(JNIEnv* env,
jclass,
jobject java_method) {
ScopedObjectAccess soa(env);
ArtMethod* method = ArtMethod::FromReflectedMethod(soa, java_method);
return reinterpret_cast64<jlong>(method);
}
extern "C" JNIEXPORT void JNICALL Java_Main_reuseArenaOfMethod(JNIEnv*,
jclass,
jlong art_method) {
void* ptr = reinterpret_cast64<void*>(art_method);
ReaderMutexLock mu(Thread::Current(), *Locks::mutator_lock_);
ReaderMutexLock mu2(Thread::Current(), *Locks::classlinker_classes_lock_);
// Check if the arena was already implicitly reused by boot classloader.
if (Runtime::Current()->GetLinearAlloc()->Contains(ptr)) {
return;
}
// Check if the arena was already implicitly reused by some other classloader.
FindPointerAllocatorVisitor visitor(ptr);
Runtime::Current()->GetClassLinker()->VisitAllocators(&visitor);
if (visitor.is_found) {
return;
}
// The arena was not reused yet. Do it explicitly.
// Create a new allocation and use it to request new arenas until one of them is
// a reused one that covers the art_method pointer.
std::unique_ptr<LinearAlloc> alloc(Runtime::Current()->CreateLinearAlloc());
do {
// Ask for a byte - it's sufficient to get an arena.
alloc->Alloc(Thread::Current(), 1);
} while (!alloc->Contains(ptr));
}
} // namespace
} // namespace art