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_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 : number_of_inline_caches_(entries.size()),
30 method_(method),
31 is_method_being_compiled_(false),
32 is_osr_method_being_compiled_(false),
33 current_inline_uses_(0),
34 saved_entry_point_(nullptr) {
35 memset(&cache_, 0, number_of_inline_caches_ * sizeof(InlineCache));
36 for (size_t i = 0; i < number_of_inline_caches_; ++i) {
37 cache_[i].dex_pc_ = entries[i];
38 }
39 }
40
Create(Thread * self,ArtMethod * method,bool retry_allocation)41 bool ProfilingInfo::Create(Thread* self, ArtMethod* method, bool retry_allocation) {
42 // Walk over the dex instructions of the method and keep track of
43 // instructions we are interested in profiling.
44 DCHECK(!method->IsNative());
45
46 const DexFile::CodeItem& code_item = *method->GetCodeItem();
47 const uint16_t* code_ptr = code_item.insns_;
48 const uint16_t* code_end = code_item.insns_ + code_item.insns_size_in_code_units_;
49
50 uint32_t dex_pc = 0;
51 std::vector<uint32_t> entries;
52 while (code_ptr < code_end) {
53 const Instruction& instruction = *Instruction::At(code_ptr);
54 switch (instruction.Opcode()) {
55 case Instruction::INVOKE_VIRTUAL:
56 case Instruction::INVOKE_VIRTUAL_RANGE:
57 case Instruction::INVOKE_VIRTUAL_QUICK:
58 case Instruction::INVOKE_VIRTUAL_RANGE_QUICK:
59 case Instruction::INVOKE_INTERFACE:
60 case Instruction::INVOKE_INTERFACE_RANGE:
61 entries.push_back(dex_pc);
62 break;
63
64 default:
65 break;
66 }
67 dex_pc += instruction.SizeInCodeUnits();
68 code_ptr += instruction.SizeInCodeUnits();
69 }
70
71 // We always create a `ProfilingInfo` object, even if there is no instruction we are
72 // interested in. The JIT code cache internally uses it.
73
74 // Allocate the `ProfilingInfo` object int the JIT's data space.
75 jit::JitCodeCache* code_cache = Runtime::Current()->GetJit()->GetCodeCache();
76 return code_cache->AddProfilingInfo(self, method, entries, retry_allocation) != nullptr;
77 }
78
GetInlineCache(uint32_t dex_pc)79 InlineCache* ProfilingInfo::GetInlineCache(uint32_t dex_pc) {
80 // TODO: binary search if array is too long.
81 for (size_t i = 0; i < number_of_inline_caches_; ++i) {
82 if (cache_[i].dex_pc_ == dex_pc) {
83 return &cache_[i];
84 }
85 }
86 LOG(FATAL) << "No inline cache found for " << ArtMethod::PrettyMethod(method_) << "@" << dex_pc;
87 UNREACHABLE();
88 }
89
AddInvokeInfo(uint32_t dex_pc,mirror::Class * cls)90 void ProfilingInfo::AddInvokeInfo(uint32_t dex_pc, mirror::Class* cls) {
91 InlineCache* cache = GetInlineCache(dex_pc);
92 for (size_t i = 0; i < InlineCache::kIndividualCacheSize; ++i) {
93 mirror::Class* existing = cache->classes_[i].Read<kWithoutReadBarrier>();
94 mirror::Class* marked = ReadBarrier::IsMarked(existing);
95 if (marked == cls) {
96 // Receiver type is already in the cache, nothing else to do.
97 return;
98 } else if (marked == nullptr) {
99 // Cache entry is empty, try to put `cls` in it.
100 // Note: it's ok to spin on 'existing' here: if 'existing' is not null, that means
101 // it is a stalled heap address, which will only be cleared during SweepSystemWeaks,
102 // *after* this thread hits a suspend point.
103 GcRoot<mirror::Class> expected_root(existing);
104 GcRoot<mirror::Class> desired_root(cls);
105 if (!reinterpret_cast<Atomic<GcRoot<mirror::Class>>*>(&cache->classes_[i])->
106 CompareExchangeStrongSequentiallyConsistent(expected_root, desired_root)) {
107 // Some other thread put a class in the cache, continue iteration starting at this
108 // entry in case the entry contains `cls`.
109 --i;
110 } else {
111 // We successfully set `cls`, just return.
112 return;
113 }
114 }
115 }
116 // Unsuccessfull - cache is full, making it megamorphic. We do not DCHECK it though,
117 // as the garbage collector might clear the entries concurrently.
118 }
119
120 } // namespace art
121