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 "profiling_info.h"
18
19 #include "art_method-inl.h"
20 #include "dex/dex_instruction.h"
21 #include "jit/jit.h"
22 #include "jit/jit_code_cache.h"
23 #include "scoped_thread_state_change-inl.h"
24 #include "thread.h"
25
26 namespace art {
27
ProfilingInfo(ArtMethod * method,const std::vector<uint32_t> & entries)28 ProfilingInfo::ProfilingInfo(ArtMethod* method, const std::vector<uint32_t>& entries)
29 : baseline_hotness_count_(0),
30 method_(method),
31 saved_entry_point_(nullptr),
32 number_of_inline_caches_(entries.size()),
33 current_inline_uses_(0) {
34 memset(&cache_, 0, number_of_inline_caches_ * sizeof(InlineCache));
35 for (size_t i = 0; i < number_of_inline_caches_; ++i) {
36 cache_[i].dex_pc_ = entries[i];
37 }
38 }
39
Create(Thread * self,ArtMethod * method,bool retry_allocation)40 bool ProfilingInfo::Create(Thread* self, ArtMethod* method, bool retry_allocation) {
41 // Walk over the dex instructions of the method and keep track of
42 // instructions we are interested in profiling.
43 DCHECK(!method->IsNative());
44
45 std::vector<uint32_t> entries;
46 for (const DexInstructionPcPair& inst : method->DexInstructions()) {
47 switch (inst->Opcode()) {
48 case Instruction::INVOKE_VIRTUAL:
49 case Instruction::INVOKE_VIRTUAL_RANGE:
50 case Instruction::INVOKE_VIRTUAL_QUICK:
51 case Instruction::INVOKE_VIRTUAL_RANGE_QUICK:
52 case Instruction::INVOKE_INTERFACE:
53 case Instruction::INVOKE_INTERFACE_RANGE:
54 entries.push_back(inst.DexPc());
55 break;
56
57 default:
58 break;
59 }
60 }
61
62 // We always create a `ProfilingInfo` object, even if there is no instruction we are
63 // interested in. The JIT code cache internally uses it.
64
65 // Allocate the `ProfilingInfo` object int the JIT's data space.
66 jit::JitCodeCache* code_cache = Runtime::Current()->GetJit()->GetCodeCache();
67 return code_cache->AddProfilingInfo(self, method, entries, retry_allocation) != nullptr;
68 }
69
GetInlineCache(uint32_t dex_pc)70 InlineCache* ProfilingInfo::GetInlineCache(uint32_t dex_pc) {
71 // TODO: binary search if array is too long.
72 for (size_t i = 0; i < number_of_inline_caches_; ++i) {
73 if (cache_[i].dex_pc_ == dex_pc) {
74 return &cache_[i];
75 }
76 }
77 LOG(FATAL) << "No inline cache found for " << ArtMethod::PrettyMethod(method_) << "@" << dex_pc;
78 UNREACHABLE();
79 }
80
AddInvokeInfo(uint32_t dex_pc,mirror::Class * cls)81 void ProfilingInfo::AddInvokeInfo(uint32_t dex_pc, mirror::Class* cls) {
82 InlineCache* cache = GetInlineCache(dex_pc);
83 for (size_t i = 0; i < InlineCache::kIndividualCacheSize; ++i) {
84 mirror::Class* existing = cache->classes_[i].Read<kWithoutReadBarrier>();
85 mirror::Class* marked = ReadBarrier::IsMarked(existing);
86 if (marked == cls) {
87 // Receiver type is already in the cache, nothing else to do.
88 return;
89 } else if (marked == nullptr) {
90 // Cache entry is empty, try to put `cls` in it.
91 // Note: it's ok to spin on 'existing' here: if 'existing' is not null, that means
92 // it is a stalled heap address, which will only be cleared during SweepSystemWeaks,
93 // *after* this thread hits a suspend point.
94 GcRoot<mirror::Class> expected_root(existing);
95 GcRoot<mirror::Class> desired_root(cls);
96 auto atomic_root = reinterpret_cast<Atomic<GcRoot<mirror::Class>>*>(&cache->classes_[i]);
97 if (!atomic_root->CompareAndSetStrongSequentiallyConsistent(expected_root, desired_root)) {
98 // Some other thread put a class in the cache, continue iteration starting at this
99 // entry in case the entry contains `cls`.
100 --i;
101 } else {
102 // We successfully set `cls`, just return.
103 return;
104 }
105 }
106 }
107 // Unsuccessfull - cache is full, making it megamorphic. We do not DCHECK it though,
108 // as the garbage collector might clear the entries concurrently.
109 }
110
111 } // namespace art
112