1 /*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "jni.h"
18
19 #include <iostream>
20
21 #include "art_method.h"
22 #include "base/casts.h"
23 #include "class_linker.h"
24 #include "jit/jit.h"
25 #include "linear_alloc.h"
26 #include "nativehelper/ScopedUtfChars.h"
27 #include "runtime.h"
28 #include "scoped_thread_state_change-inl.h"
29 #include "thread-current-inl.h"
30
31 namespace art {
32 namespace {
33
34 class FindPointerAllocatorVisitor : public AllocatorVisitor {
35 public:
FindPointerAllocatorVisitor(void * ptr)36 explicit FindPointerAllocatorVisitor(void* ptr) : is_found(false), ptr_(ptr) {}
37
Visit(LinearAlloc * alloc)38 bool Visit(LinearAlloc* alloc)
39 REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_) override {
40 is_found = alloc->Contains(ptr_);
41 return !is_found;
42 }
43
44 bool is_found;
45
46 private:
47 void* ptr_;
48 };
49
Java_Main_getArtMethod(JNIEnv * env,jclass,jobject java_method)50 extern "C" JNIEXPORT jlong JNICALL Java_Main_getArtMethod(JNIEnv* env,
51 jclass,
52 jobject java_method) {
53 ScopedObjectAccess soa(env);
54 ArtMethod* method = ArtMethod::FromReflectedMethod(soa, java_method);
55 return reinterpret_cast64<jlong>(method);
56 }
57
Java_Main_reuseArenaOfMethod(JNIEnv *,jclass,jlong art_method)58 extern "C" JNIEXPORT void JNICALL Java_Main_reuseArenaOfMethod(JNIEnv*,
59 jclass,
60 jlong art_method) {
61 void* ptr = reinterpret_cast64<void*>(art_method);
62
63 ReaderMutexLock mu(Thread::Current(), *Locks::mutator_lock_);
64 ReaderMutexLock mu2(Thread::Current(), *Locks::classlinker_classes_lock_);
65 // Check if the arena was already implicitly reused by boot classloader.
66 if (Runtime::Current()->GetLinearAlloc()->Contains(ptr)) {
67 return;
68 }
69
70 // Check if the arena was already implicitly reused by some other classloader.
71 FindPointerAllocatorVisitor visitor(ptr);
72 Runtime::Current()->GetClassLinker()->VisitAllocators(&visitor);
73 if (visitor.is_found) {
74 return;
75 }
76
77 // The arena was not reused yet. Do it explicitly.
78 // Create a new allocation and use it to request new arenas until one of them is
79 // a reused one that covers the art_method pointer.
80 std::unique_ptr<LinearAlloc> alloc(Runtime::Current()->CreateLinearAlloc());
81 do {
82 // Ask for a byte - it's sufficient to get an arena.
83 alloc->Alloc(Thread::Current(), 1);
84 } while (!alloc->Contains(ptr));
85 }
86
87 } // namespace
88 } // namespace art
89