1 /*
2  * Copyright (C) 2013 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 <algorithm>
18 #include <utility>
19 #include "thread.h"
20 #include "thread-inl.h"
21 #include "base/mutex.h"
22 #include "base/mutex-inl.h"
23 #include "base/logging.h"
24 #include "driver/compiler_driver.h"
25 
26 #include "dex_file_to_method_inliner_map.h"
27 
28 namespace art {
29 
DexFileToMethodInlinerMap()30 DexFileToMethodInlinerMap::DexFileToMethodInlinerMap()
31     : lock_("DexFileToMethodInlinerMap lock", kDexFileToMethodInlinerMapLock) {
32 }
33 
~DexFileToMethodInlinerMap()34 DexFileToMethodInlinerMap::~DexFileToMethodInlinerMap() {
35   for (auto& entry : inliners_) {
36     delete entry.second;
37   }
38 }
39 
GetMethodInliner(const DexFile * dex_file)40 DexFileMethodInliner* DexFileToMethodInlinerMap::GetMethodInliner(const DexFile* dex_file) {
41   Thread* self = Thread::Current();
42   {
43     ReaderMutexLock mu(self, lock_);
44     auto it = inliners_.find(dex_file);
45     if (it != inliners_.end()) {
46       return it->second;
47     }
48   }
49 
50   // We need to acquire our lock_ to modify inliners_ but we want to release it
51   // before we initialize the new inliner. However, we need to acquire the
52   // new inliner's lock_ before we release our lock_ to prevent another thread
53   // from using the uninitialized inliner. This requires explicit calls to
54   // ExclusiveLock()/ExclusiveUnlock() on one of the locks, the other one
55   // can use WriterMutexLock.
56   DexFileMethodInliner* locked_inliner;
57   {
58     WriterMutexLock mu(self, lock_);
59     DexFileMethodInliner** inliner = &inliners_[dex_file];  // inserts new entry if not found
60     if (*inliner) {
61       return *inliner;
62     }
63     *inliner = new DexFileMethodInliner;
64     DCHECK(*inliner != nullptr);
65     locked_inliner = *inliner;
66     locked_inliner->lock_.ExclusiveLock(self);  // Acquire inliner's lock_ before releasing lock_.
67   }
68   locked_inliner->FindIntrinsics(dex_file);
69   locked_inliner->lock_.ExclusiveUnlock(self);
70   return locked_inliner;
71 }
72 
73 }  // namespace art
74