Home | History | Annotate | Download | only in jit 
      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 
     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 
     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   std::vector<uint32_t> entries;
     47   for (const DexInstructionPcPair& inst : method->DexInstructions()) {
     48     switch (inst->Opcode()) {
     49       case Instruction::INVOKE_VIRTUAL:
     50       case Instruction::INVOKE_VIRTUAL_RANGE:
     51       case Instruction::INVOKE_VIRTUAL_QUICK:
     52       case Instruction::INVOKE_VIRTUAL_RANGE_QUICK:
     53       case Instruction::INVOKE_INTERFACE:
     54       case Instruction::INVOKE_INTERFACE_RANGE:
     55         entries.push_back(inst.DexPc());
     56         break;
     57 
     58       default:
     59         break;
     60     }
     61   }
     62 
     63   // We always create a `ProfilingInfo` object, even if there is no instruction we are
     64   // interested in. The JIT code cache internally uses it.
     65 
     66   // Allocate the `ProfilingInfo` object int the JIT's data space.
     67   jit::JitCodeCache* code_cache = Runtime::Current()->GetJit()->GetCodeCache();
     68   return code_cache->AddProfilingInfo(self, method, entries, retry_allocation) != nullptr;
     69 }
     70 
     71 InlineCache* ProfilingInfo::GetInlineCache(uint32_t dex_pc) {
     72   // TODO: binary search if array is too long.
     73   for (size_t i = 0; i < number_of_inline_caches_; ++i) {
     74     if (cache_[i].dex_pc_ == dex_pc) {
     75       return &cache_[i];
     76     }
     77   }
     78   LOG(FATAL) << "No inline cache found for "  << ArtMethod::PrettyMethod(method_) << "@" << dex_pc;
     79   UNREACHABLE();
     80 }
     81 
     82 void ProfilingInfo::AddInvokeInfo(uint32_t dex_pc, mirror::Class* cls) {
     83   InlineCache* cache = GetInlineCache(dex_pc);
     84   for (size_t i = 0; i < InlineCache::kIndividualCacheSize; ++i) {
     85     mirror::Class* existing = cache->classes_[i].Read<kWithoutReadBarrier>();
     86     mirror::Class* marked = ReadBarrier::IsMarked(existing);
     87     if (marked == cls) {
     88       // Receiver type is already in the cache, nothing else to do.
     89       return;
     90     } else if (marked == nullptr) {
     91       // Cache entry is empty, try to put `cls` in it.
     92       // Note: it's ok to spin on 'existing' here: if 'existing' is not null, that means
     93       // it is a stalled heap address, which will only be cleared during SweepSystemWeaks,
     94       // *after* this thread hits a suspend point.
     95       GcRoot<mirror::Class> expected_root(existing);
     96       GcRoot<mirror::Class> desired_root(cls);
     97       auto atomic_root = reinterpret_cast<Atomic<GcRoot<mirror::Class>>*>(&cache->classes_[i]);
     98       if (!atomic_root->CompareAndSetStrongSequentiallyConsistent(expected_root, desired_root)) {
     99         // Some other thread put a class in the cache, continue iteration starting at this
    100         // entry in case the entry contains `cls`.
    101         --i;
    102       } else {
    103         // We successfully set `cls`, just return.
    104         return;
    105       }
    106     }
    107   }
    108   // Unsuccessfull - cache is full, making it megamorphic. We do not DCHECK it though,
    109   // as the garbage collector might clear the entries concurrently.
    110 }
    111 
    112 }  // namespace art
    113