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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 "dex_cache_array_fixups_arm.h"
#include "base/arena_containers.h"
#ifdef ART_USE_OLD_ARM_BACKEND
#include "code_generator_arm.h"
#include "intrinsics_arm.h"
#else
#include "code_generator_arm_vixl.h"
#include "intrinsics_arm_vixl.h"
#endif
#include "utils/dex_cache_arrays_layout-inl.h"
namespace art {
namespace arm {
#ifdef ART_USE_OLD_ARM_BACKEND
typedef CodeGeneratorARM CodeGeneratorARMType;
typedef IntrinsicLocationsBuilderARM IntrinsicLocationsBuilderARMType;
#else
typedef CodeGeneratorARMVIXL CodeGeneratorARMType;
typedef IntrinsicLocationsBuilderARMVIXL IntrinsicLocationsBuilderARMType;
#endif
/**
* Finds instructions that need the dex cache arrays base as an input.
*/
class DexCacheArrayFixupsVisitor : public HGraphVisitor {
public:
DexCacheArrayFixupsVisitor(HGraph* graph, CodeGenerator* codegen)
: HGraphVisitor(graph),
codegen_(down_cast<CodeGeneratorARMType*>(codegen)),
dex_cache_array_bases_(std::less<const DexFile*>(),
// Attribute memory use to code generator.
graph->GetArena()->Adapter(kArenaAllocCodeGenerator)) {}
void MoveBasesIfNeeded() {
for (const auto& entry : dex_cache_array_bases_) {
// Bring the base closer to the first use (previously, it was in the
// entry block) and relieve some pressure on the register allocator
// while avoiding recalculation of the base in a loop.
HArmDexCacheArraysBase* base = entry.second;
base->MoveBeforeFirstUserAndOutOfLoops();
}
}
private:
void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) OVERRIDE {
// If this is an invoke with PC-relative access to the dex cache methods array,
// we need to add the dex cache arrays base as the special input.
if (invoke->HasPcRelativeDexCache() &&
!IsCallFreeIntrinsic<IntrinsicLocationsBuilderARMType>(invoke, codegen_)) {
HArmDexCacheArraysBase* base =
GetOrCreateDexCacheArrayBase(invoke->GetDexFileForPcRelativeDexCache());
// Update the element offset in base.
DexCacheArraysLayout layout(kArmPointerSize, &invoke->GetDexFileForPcRelativeDexCache());
base->UpdateElementOffset(layout.MethodOffset(invoke->GetDexMethodIndex()));
// Add the special argument base to the method.
DCHECK(!invoke->HasCurrentMethodInput());
invoke->AddSpecialInput(base);
}
}
HArmDexCacheArraysBase* GetOrCreateDexCacheArrayBase(const DexFile& dex_file) {
// Ensure we only initialize the pointer once for each dex file.
auto lb = dex_cache_array_bases_.lower_bound(&dex_file);
if (lb != dex_cache_array_bases_.end() &&
!dex_cache_array_bases_.key_comp()(&dex_file, lb->first)) {
return lb->second;
}
// Insert the base at the start of the entry block, move it to a better
// position later in MoveBaseIfNeeded().
HArmDexCacheArraysBase* base = new (GetGraph()->GetArena()) HArmDexCacheArraysBase(dex_file);
HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
entry_block->InsertInstructionBefore(base, entry_block->GetFirstInstruction());
dex_cache_array_bases_.PutBefore(lb, &dex_file, base);
return base;
}
CodeGeneratorARMType* codegen_;
using DexCacheArraysBaseMap =
ArenaSafeMap<const DexFile*, HArmDexCacheArraysBase*, std::less<const DexFile*>>;
DexCacheArraysBaseMap dex_cache_array_bases_;
};
void DexCacheArrayFixups::Run() {
if (graph_->HasIrreducibleLoops()) {
// Do not run this optimization, as irreducible loops do not work with an instruction
// that can be live-in at the irreducible loop header.
return;
}
DexCacheArrayFixupsVisitor visitor(graph_, codegen_);
visitor.VisitInsertionOrder();
visitor.MoveBasesIfNeeded();
}
} // namespace arm
} // namespace art