compiler/optimizing/builder.cc

/*
 * 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 "builder.h"

#include "art_field-inl.h"
#include "base/arena_bit_vector.h"
#include "base/bit_vector-inl.h"
#include "base/logging.h"
#include "block_builder.h"
#include "data_type-inl.h"
#include "dex/verified_method.h"
#include "driver/compiler_options.h"
#include "instruction_builder.h"
#include "mirror/class_loader.h"
#include "mirror/dex_cache.h"
#include "nodes.h"
#include "optimizing_compiler_stats.h"
#include "ssa_builder.h"
#include "thread.h"
#include "utils/dex_cache_arrays_layout-inl.h"

namespace art {

HGraphBuilder::HGraphBuilder(HGraph* graph,
                             const DexCompilationUnit* dex_compilation_unit,
                             const DexCompilationUnit* outer_compilation_unit,
                             CompilerDriver* driver,
                             CodeGenerator* code_generator,
                             OptimizingCompilerStats* compiler_stats,
                             const uint8_t* interpreter_metadata,
                             VariableSizedHandleScope* handles)
    : graph_(graph),
      dex_file_(&graph->GetDexFile()),
      code_item_(*dex_compilation_unit->GetCodeItem()),
      dex_compilation_unit_(dex_compilation_unit),
      outer_compilation_unit_(outer_compilation_unit),
      compiler_driver_(driver),
      code_generator_(code_generator),
      compilation_stats_(compiler_stats),
      interpreter_metadata_(interpreter_metadata),
      handles_(handles),
      return_type_(DataType::FromShorty(dex_compilation_unit_->GetShorty()[0])) {}

bool HGraphBuilder::SkipCompilation(size_t number_of_branches) {
  if (compiler_driver_ == nullptr) {
    // Note that the compiler driver is null when unit testing.
    return false;
  }

  const CompilerOptions& compiler_options = compiler_driver_->GetCompilerOptions();
  CompilerFilter::Filter compiler_filter = compiler_options.GetCompilerFilter();
  if (compiler_filter == CompilerFilter::kEverything) {
    return false;
  }

  if (compiler_options.IsHugeMethod(code_item_.insns_size_in_code_units_)) {
    VLOG(compiler) << "Skip compilation of huge method "
                   << dex_file_->PrettyMethod(dex_compilation_unit_->GetDexMethodIndex())
                   << ": " << code_item_.insns_size_in_code_units_ << " code units";
    MaybeRecordStat(compilation_stats_,
                    MethodCompilationStat::kNotCompiledHugeMethod);
    return true;
  }

  // If it's large and contains no branches, it's likely to be machine generated initialization.
  if (compiler_options.IsLargeMethod(code_item_.insns_size_in_code_units_)
      && (number_of_branches == 0)) {
    VLOG(compiler) << "Skip compilation of large method with no branch "
                   << dex_file_->PrettyMethod(dex_compilation_unit_->GetDexMethodIndex())
                   << ": " << code_item_.insns_size_in_code_units_ << " code units";
    MaybeRecordStat(compilation_stats_,
                    MethodCompilationStat::kNotCompiledLargeMethodNoBranches);
    return true;
  }

  return false;
}

GraphAnalysisResult HGraphBuilder::BuildGraph() {
  DCHECK(graph_->GetBlocks().empty());

  graph_->SetNumberOfVRegs(code_item_.registers_size_);
  graph_->SetNumberOfInVRegs(code_item_.ins_size_);
  graph_->SetMaximumNumberOfOutVRegs(code_item_.outs_size_);
  graph_->SetHasTryCatch(code_item_.tries_size_ != 0);

  // Use ScopedArenaAllocator for all local allocations.
  ScopedArenaAllocator local_allocator(graph_->GetArenaStack());
  HBasicBlockBuilder block_builder(graph_, dex_file_, code_item_, &local_allocator);
  SsaBuilder ssa_builder(graph_,
                         dex_compilation_unit_->GetClassLoader(),
                         dex_compilation_unit_->GetDexCache(),
                         handles_,
                         &local_allocator);
  HInstructionBuilder instruction_builder(graph_,
                                          &block_builder,
                                          &ssa_builder,
                                          dex_file_,
                                          code_item_,
                                          return_type_,
                                          dex_compilation_unit_,
                                          outer_compilation_unit_,
                                          compiler_driver_,
                                          code_generator_,
                                          interpreter_metadata_,
                                          compilation_stats_,
                                          handles_,
                                          &local_allocator);

  // 1) Create basic blocks and link them together. Basic blocks are left
  //    unpopulated with the exception of synthetic blocks, e.g. HTryBoundaries.
  if (!block_builder.Build()) {
    return kAnalysisInvalidBytecode;
  }

  // 2) Decide whether to skip this method based on its code size and number
  //    of branches.
  if (SkipCompilation(block_builder.GetNumberOfBranches())) {
    return kAnalysisSkipped;
  }

  // 3) Build the dominator tree and fill in loop and try/catch metadata.
  GraphAnalysisResult result = graph_->BuildDominatorTree();
  if (result != kAnalysisSuccess) {
    return result;
  }

  // 4) Populate basic blocks with instructions.
  if (!instruction_builder.Build()) {
    return kAnalysisInvalidBytecode;
  }

  // 5) Type the graph and eliminate dead/redundant phis.
  return ssa_builder.BuildSsa();
}

}  // namespace art