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