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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "profiling_info.h"
#include "art_method-inl.h"
#include "dex/dex_instruction.h"
#include "jit/jit.h"
#include "jit/jit_code_cache.h"
#include "scoped_thread_state_change-inl.h"
#include "thread.h"
namespace art {
ProfilingInfo::ProfilingInfo(ArtMethod* method,
const std::vector<uint32_t>& inline_cache_entries,
const std::vector<uint32_t>& branch_cache_entries)
: baseline_hotness_count_(GetOptimizeThreshold()),
method_(method),
number_of_inline_caches_(inline_cache_entries.size()),
number_of_branch_caches_(branch_cache_entries.size()),
current_inline_uses_(0) {
InlineCache* inline_caches = GetInlineCaches();
memset(inline_caches, 0, number_of_inline_caches_ * sizeof(InlineCache));
for (size_t i = 0; i < number_of_inline_caches_; ++i) {
inline_caches[i].dex_pc_ = inline_cache_entries[i];
}
BranchCache* branch_caches = GetBranchCaches();
memset(branch_caches, 0, number_of_branch_caches_ * sizeof(BranchCache));
for (size_t i = 0; i < number_of_branch_caches_; ++i) {
branch_caches[i].dex_pc_ = branch_cache_entries[i];
}
}
uint16_t ProfilingInfo::GetOptimizeThreshold() {
return Runtime::Current()->GetJITOptions()->GetOptimizeThreshold();
}
ProfilingInfo* ProfilingInfo::Create(Thread* self,
ArtMethod* method,
const std::vector<uint32_t>& inline_cache_entries) {
// Walk over the dex instructions of the method and keep track of
// instructions we are interested in profiling.
DCHECK(!method->IsNative());
std::vector<uint32_t> branch_cache_entries;
for (const DexInstructionPcPair& inst : method->DexInstructions()) {
switch (inst->Opcode()) {
case Instruction::IF_EQ:
case Instruction::IF_EQZ:
case Instruction::IF_NE:
case Instruction::IF_NEZ:
case Instruction::IF_LT:
case Instruction::IF_LTZ:
case Instruction::IF_LE:
case Instruction::IF_LEZ:
case Instruction::IF_GT:
case Instruction::IF_GTZ:
case Instruction::IF_GE:
case Instruction::IF_GEZ:
branch_cache_entries.push_back(inst.DexPc());
break;
default:
break;
}
}
// We always create a `ProfilingInfo` object, even if there is no instruction we are
// interested in. The JIT code cache internally uses it for hotness counter.
// Allocate the `ProfilingInfo` object int the JIT's data space.
jit::JitCodeCache* code_cache = Runtime::Current()->GetJit()->GetCodeCache();
return code_cache->AddProfilingInfo(self, method, inline_cache_entries, branch_cache_entries);
}
InlineCache* ProfilingInfo::GetInlineCache(uint32_t dex_pc) {
// TODO: binary search if array is too long.
InlineCache* caches = GetInlineCaches();
for (size_t i = 0; i < number_of_inline_caches_; ++i) {
if (caches[i].dex_pc_ == dex_pc) {
return &caches[i];
}
}
return nullptr;
}
BranchCache* ProfilingInfo::GetBranchCache(uint32_t dex_pc) {
// TODO: binary search if array is too long.
BranchCache* caches = GetBranchCaches();
for (size_t i = 0; i < number_of_branch_caches_; ++i) {
if (caches[i].dex_pc_ == dex_pc) {
return &caches[i];
}
}
// Currently, only if instructions are profiled. The compiler will see other
// branches, like switches.
return nullptr;
}
void ProfilingInfo::AddInvokeInfo(uint32_t dex_pc, mirror::Class* cls) {
InlineCache* cache = GetInlineCache(dex_pc);
if (cache == nullptr) {
return;
}
for (size_t i = 0; i < InlineCache::kIndividualCacheSize; ++i) {
mirror::Class* existing = cache->classes_[i].Read<kWithoutReadBarrier>();
mirror::Class* marked = ReadBarrier::IsMarked(existing);
if (marked == cls) {
// Receiver type is already in the cache, nothing else to do.
return;
} else if (marked == nullptr) {
// Cache entry is empty, try to put `cls` in it.
// Note: it's ok to spin on 'existing' here: if 'existing' is not null, that means
// it is a stalled heap address, which will only be cleared during SweepSystemWeaks,
// *after* this thread hits a suspend point.
GcRoot<mirror::Class> expected_root(existing);
GcRoot<mirror::Class> desired_root(cls);
auto atomic_root = reinterpret_cast<Atomic<GcRoot<mirror::Class>>*>(&cache->classes_[i]);
if (!atomic_root->CompareAndSetStrongSequentiallyConsistent(expected_root, desired_root)) {
// Some other thread put a class in the cache, continue iteration starting at this
// entry in case the entry contains `cls`.
--i;
} else {
// We successfully set `cls`, just return.
return;
}
}
}
// Unsuccessfull - cache is full, making it megamorphic. We do not DCHECK it though,
// as the garbage collector might clear the entries concurrently.
}
ScopedProfilingInfoUse::ScopedProfilingInfoUse(jit::Jit* jit, ArtMethod* method, Thread* self)
: jit_(jit),
method_(method),
self_(self),
// Fetch the profiling info ahead of using it. If it's null when fetching,
// we should not call JitCodeCache::DoneCompilerUse.
profiling_info_(jit == nullptr
? nullptr
: jit->GetCodeCache()->NotifyCompilerUse(method, self))
{}
ScopedProfilingInfoUse::~ScopedProfilingInfoUse() {
if (profiling_info_ != nullptr) {
jit_->GetCodeCache()->DoneCompilerUse(method_, self_);
}
}
uint32_t InlineCache::EncodeDexPc(ArtMethod* method,
const std::vector<uint32_t>& dex_pcs,
uint32_t inline_max_code_units) {
if (kIsDebugBuild) {
// Make sure `inline_max_code_units` is always the same.
static uint32_t global_max_code_units = inline_max_code_units;
CHECK_EQ(global_max_code_units, inline_max_code_units);
}
if (dex_pcs.size() - 1 > MaxDexPcEncodingDepth(method, inline_max_code_units)) {
return -1;
}
uint32_t size = dex_pcs.size();
uint32_t insns_size = method->DexInstructions().InsnsSizeInCodeUnits();
uint32_t dex_pc = dex_pcs[size - 1];
uint32_t shift = MinimumBitsToStore(insns_size - 1);
for (uint32_t i = size - 1; i > 0; --i) {
DCHECK_LT(shift, BitSizeOf<uint32_t>());
dex_pc += ((dex_pcs[i - 1] + 1) << shift);
shift += MinimumBitsToStore(inline_max_code_units);
}
return dex_pc;
}
uint32_t InlineCache::MaxDexPcEncodingDepth(ArtMethod* method, uint32_t inline_max_code_units) {
uint32_t insns_size = method->DexInstructions().InsnsSizeInCodeUnits();
uint32_t num_bits = MinimumBitsToStore(insns_size - 1);
uint32_t depth = 0;
do {
depth++;
num_bits += MinimumBitsToStore(inline_max_code_units);
} while (num_bits <= BitSizeOf<uint32_t>());
return depth - 1;
}
} // namespace art
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