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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 "dex/verified_method.h"
#include "driver/dex_compilation_unit.h"
#include "gc_map_builder.h"
#include "leb128.h"
#include "mapping_table.h"
#include "utils/assembler.h"
#include "verifier/dex_gc_map.h"
#include "vmap_table.h"
namespace art {
void CodeGenerator::Compile(CodeAllocator* allocator) {
const GrowableArray<HBasicBlock*>* blocks = GetGraph()->GetBlocks();
DCHECK(blocks->Get(0) == GetGraph()->GetEntryBlock());
DCHECK(GoesToNextBlock(GetGraph()->GetEntryBlock(), blocks->Get(1)));
CompileEntryBlock();
for (size_t i = 1; i < blocks->Size(); i++) {
CompileBlock(blocks->Get(i));
}
size_t code_size = GetAssembler()->CodeSize();
uint8_t* buffer = allocator->Allocate(code_size);
MemoryRegion code(buffer, code_size);
GetAssembler()->FinalizeInstructions(code);
}
void CodeGenerator::CompileEntryBlock() {
HGraphVisitor* location_builder = GetLocationBuilder();
HGraphVisitor* instruction_visitor = GetInstructionVisitor();
// The entry block contains all locals for this method. By visiting the entry block,
// we're computing the required frame size.
for (HInstructionIterator it(GetGraph()->GetEntryBlock()); !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->GetLocations() == nullptr);
}
current->Accept(instruction_visitor);
}
GenerateFrameEntry();
}
void CodeGenerator::CompileBlock(HBasicBlock* block) {
Bind(GetLabelOf(block));
HGraphVisitor* location_builder = GetLocationBuilder();
HGraphVisitor* instruction_visitor = GetInstructionVisitor();
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(instruction_visitor);
if (current->GetLocations() != nullptr && current->GetLocations()->Out().IsValid()) {
Push(current, current->GetLocations()->Out());
}
}
}
void CodeGenerator::InitLocations(HInstruction* instruction) {
if (instruction->GetLocations() == nullptr) return;
for (int i = 0; i < instruction->InputCount(); i++) {
Location location = instruction->GetLocations()->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->GetBlockId() + 1 == next->GetBlockId();
}
Label* CodeGenerator::GetLabelOf(HBasicBlock* block) const {
return block_labels_.GetRawStorage() + block->GetBlockId();
}
CodeGenerator* CodeGenerator::Create(ArenaAllocator* allocator,
HGraph* graph,
InstructionSet instruction_set) {
switch (instruction_set) {
case kArm:
case kThumb2: {
return new (allocator) arm::CodeGeneratorARM(graph);
}
case kMips:
return nullptr;
case kX86: {
return new (allocator) x86::CodeGeneratorX86(graph);
}
case kX86_64: {
return new (allocator) x86::CodeGeneratorX86(graph);
}
default:
return nullptr;
}
}
void CodeGenerator::BuildNativeGCMap(
std::vector<uint8_t>* data, const DexCompilationUnit& dex_compilation_unit) const {
const std::vector<uint8_t>& gc_map_raw =
dex_compilation_unit.GetVerifiedMethod()->GetDexGcMap();
verifier::DexPcToReferenceMap dex_gc_map(&(gc_map_raw)[0]);
uint32_t max_native_offset = 0;
for (size_t i = 0; i < pc_infos_.Size(); i++) {
uint32_t native_offset = pc_infos_.Get(i).native_pc;
if (native_offset > max_native_offset) {
max_native_offset = native_offset;
}
}
GcMapBuilder builder(data, pc_infos_.Size(), max_native_offset, dex_gc_map.RegWidth());
for (size_t i = 0; i < pc_infos_.Size(); i++) {
struct PcInfo pc_info = pc_infos_.Get(i);
uint32_t native_offset = pc_info.native_pc;
uint32_t dex_pc = pc_info.dex_pc;
const uint8_t* references = dex_gc_map.FindBitMap(dex_pc, false);
CHECK(references != NULL) << "Missing ref for dex pc 0x" << std::hex << dex_pc;
builder.AddEntry(native_offset, references);
}
}
void CodeGenerator::BuildMappingTable(std::vector<uint8_t>* data) const {
uint32_t pc2dex_data_size = 0u;
uint32_t pc2dex_entries = pc_infos_.Size();
uint32_t pc2dex_offset = 0u;
int32_t pc2dex_dalvik_offset = 0;
uint32_t dex2pc_data_size = 0u;
uint32_t dex2pc_entries = 0u;
// We currently only have pc2dex entries.
for (size_t i = 0; i < pc2dex_entries; i++) {
struct PcInfo pc_info = pc_infos_.Get(i);
pc2dex_data_size += UnsignedLeb128Size(pc_info.native_pc - pc2dex_offset);
pc2dex_data_size += SignedLeb128Size(pc_info.dex_pc - pc2dex_dalvik_offset);
pc2dex_offset = pc_info.native_pc;
pc2dex_dalvik_offset = pc_info.dex_pc;
}
uint32_t total_entries = pc2dex_entries + dex2pc_entries;
uint32_t hdr_data_size = UnsignedLeb128Size(total_entries) + UnsignedLeb128Size(pc2dex_entries);
uint32_t data_size = hdr_data_size + pc2dex_data_size + dex2pc_data_size;
data->resize(data_size);
uint8_t* data_ptr = &(*data)[0];
uint8_t* write_pos = data_ptr;
write_pos = EncodeUnsignedLeb128(write_pos, total_entries);
write_pos = EncodeUnsignedLeb128(write_pos, pc2dex_entries);
DCHECK_EQ(static_cast<size_t>(write_pos - data_ptr), hdr_data_size);
uint8_t* write_pos2 = write_pos + pc2dex_data_size;
pc2dex_offset = 0u;
pc2dex_dalvik_offset = 0u;
for (size_t i = 0; i < pc2dex_entries; i++) {
struct PcInfo pc_info = pc_infos_.Get(i);
DCHECK(pc2dex_offset <= pc_info.native_pc);
write_pos = EncodeUnsignedLeb128(write_pos, pc_info.native_pc - pc2dex_offset);
write_pos = EncodeSignedLeb128(write_pos, pc_info.dex_pc - pc2dex_dalvik_offset);
pc2dex_offset = pc_info.native_pc;
pc2dex_dalvik_offset = pc_info.dex_pc;
}
DCHECK_EQ(static_cast<size_t>(write_pos - data_ptr), hdr_data_size + pc2dex_data_size);
DCHECK_EQ(static_cast<size_t>(write_pos2 - data_ptr), data_size);
if (kIsDebugBuild) {
// Verify the encoded table holds the expected data.
MappingTable table(data_ptr);
CHECK_EQ(table.TotalSize(), total_entries);
CHECK_EQ(table.PcToDexSize(), pc2dex_entries);
auto it = table.PcToDexBegin();
auto it2 = table.DexToPcBegin();
for (size_t i = 0; i < pc2dex_entries; i++) {
struct PcInfo pc_info = pc_infos_.Get(i);
CHECK_EQ(pc_info.native_pc, it.NativePcOffset());
CHECK_EQ(pc_info.dex_pc, it.DexPc());
++it;
}
CHECK(it == table.PcToDexEnd());
CHECK(it2 == table.DexToPcEnd());
}
}
void CodeGenerator::BuildVMapTable(std::vector<uint8_t>* data) const {
Leb128EncodingVector vmap_encoder;
size_t size = 1 + 1 /* marker */ + 0;
vmap_encoder.Reserve(size + 1u); // All values are likely to be one byte in ULEB128 (<128).
vmap_encoder.PushBackUnsigned(size);
// We're currently always saving the frame pointer, so set it in the table as a temporary.
vmap_encoder.PushBackUnsigned(kVRegTempBaseReg + VmapTable::kEntryAdjustment);
vmap_encoder.PushBackUnsigned(VmapTable::kAdjustedFpMarker);
*data = vmap_encoder.GetData();
}
} // namespace art
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