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/*
* Copyright (C) 2014 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 "code_generator.h"
#include "code_generator_arm.h"
#include "code_generator_x86.h"
#include "utils/assembler.h"
#include "utils/arm/assembler_arm.h"
#include "utils/mips/assembler_mips.h"
#include "utils/x86/assembler_x86.h"
namespace art {
void CodeGenerator::Compile(CodeAllocator* allocator) {
const GrowableArray<HBasicBlock*>* blocks = graph()->blocks();
DCHECK(blocks->Get(0) == graph()->entry_block());
DCHECK(GoesToNextBlock(graph()->entry_block(), blocks->Get(1)));
CompileEntryBlock();
for (size_t i = 1; i < blocks->Size(); i++) {
CompileBlock(blocks->Get(i));
}
size_t code_size = assembler_->CodeSize();
uint8_t* buffer = allocator->Allocate(code_size);
MemoryRegion code(buffer, code_size);
assembler_->FinalizeInstructions(code);
}
void CodeGenerator::CompileEntryBlock() {
HGraphVisitor* location_builder = GetLocationBuilder();
// The entry block contains all locals for this method. By visiting the entry block,
// we're computing the required frame size.
for (HInstructionIterator it(graph()->entry_block()); !it.Done(); it.Advance()) {
HInstruction* current = it.Current();
// Instructions in the entry block should not generate code.
if (kIsDebugBuild) {
current->Accept(location_builder);
DCHECK(current->locations() == nullptr);
}
current->Accept(this);
}
GenerateFrameEntry();
}
void CodeGenerator::CompileBlock(HBasicBlock* block) {
Bind(GetLabelOf(block));
HGraphVisitor* location_builder = GetLocationBuilder();
for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
// For each instruction, we emulate a stack-based machine, where the inputs are popped from
// the runtime stack, and the result is pushed on the stack. We currently can do this because
// we do not perform any code motion, and the Dex format does not reference individual
// instructions but uses registers instead (our equivalent of HLocal).
HInstruction* current = it.Current();
current->Accept(location_builder);
InitLocations(current);
current->Accept(this);
if (current->locations() != nullptr && current->locations()->Out().IsValid()) {
Push(current, current->locations()->Out());
}
}
}
void CodeGenerator::InitLocations(HInstruction* instruction) {
if (instruction->locations() == nullptr) return;
for (int i = 0; i < instruction->InputCount(); i++) {
Location location = instruction->locations()->InAt(i);
if (location.IsValid()) {
// Move the input to the desired location.
Move(instruction->InputAt(i), location);
}
}
}
bool CodeGenerator::GoesToNextBlock(HBasicBlock* current, HBasicBlock* next) const {
// We currently iterate over the block in insertion order.
return current->block_id() + 1 == next->block_id();
}
Label* CodeGenerator::GetLabelOf(HBasicBlock* block) const {
return block_labels_.GetRawStorage() + block->block_id();
}
bool CodeGenerator::CompileGraph(HGraph* graph,
InstructionSet instruction_set,
CodeAllocator* allocator) {
switch (instruction_set) {
case kArm:
case kThumb2: {
arm::ArmAssembler assembler;
arm::CodeGeneratorARM(&assembler, graph).Compile(allocator);
return true;
}
case kMips:
return false;
case kX86: {
x86::X86Assembler assembler;
x86::CodeGeneratorX86(&assembler, graph).Compile(allocator);
return true;
}
default:
return false;
}
}
} // namespace art
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