compiler/dex/frontend.cc

/*
 * Copyright (C) 2011 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 <cstdint>

#include "compiler.h"
#include "compiler_internals.h"
#include "driver/compiler_driver.h"
#include "driver/compiler_options.h"
#include "dataflow_iterator-inl.h"
#include "leb128.h"
#include "mirror/object.h"
#include "pass_driver_me_opts.h"
#include "runtime.h"
#include "base/logging.h"
#include "base/timing_logger.h"
#include "driver/compiler_options.h"
#include "dex/quick/dex_file_to_method_inliner_map.h"

namespace art {

extern "C" void ArtInitQuickCompilerContext(art::CompilerDriver* driver) {
  CHECK(driver->GetCompilerContext() == nullptr);
}

extern "C" void ArtUnInitQuickCompilerContext(art::CompilerDriver* driver) {
  CHECK(driver->GetCompilerContext() == nullptr);
}

/* Default optimizer/debug setting for the compiler. */
static uint32_t kCompilerOptimizerDisableFlags = 0 |  // Disable specific optimizations
  (1 << kLoadStoreElimination) |  // TODO: this pass has been broken for awhile - fix or delete.
  // (1 << kLoadHoisting) |
  // (1 << kSuppressLoads) |
  // (1 << kNullCheckElimination) |
  // (1 << kClassInitCheckElimination) |
  // (1 << kGlobalValueNumbering) |
  // (1 << kPromoteRegs) |
  // (1 << kTrackLiveTemps) |
  // (1 << kSafeOptimizations) |
  // (1 << kBBOpt) |
  // (1 << kMatch) |
  // (1 << kPromoteCompilerTemps) |
  // (1 << kSuppressExceptionEdges) |
  // (1 << kSuppressMethodInlining) |
  0;

static uint32_t kCompilerDebugFlags = 0 |     // Enable debug/testing modes
  // (1 << kDebugDisplayMissingTargets) |
  // (1 << kDebugVerbose) |
  // (1 << kDebugDumpCFG) |
  // (1 << kDebugSlowFieldPath) |
  // (1 << kDebugSlowInvokePath) |
  // (1 << kDebugSlowStringPath) |
  // (1 << kDebugSlowestFieldPath) |
  // (1 << kDebugSlowestStringPath) |
  // (1 << kDebugExerciseResolveMethod) |
  // (1 << kDebugVerifyDataflow) |
  // (1 << kDebugShowMemoryUsage) |
  // (1 << kDebugShowNops) |
  // (1 << kDebugCountOpcodes) |
  // (1 << kDebugDumpCheckStats) |
  // (1 << kDebugDumpBitcodeFile) |
  // (1 << kDebugVerifyBitcode) |
  // (1 << kDebugShowSummaryMemoryUsage) |
  // (1 << kDebugShowFilterStats) |
  // (1 << kDebugTimings) |
  // (1 << kDebugCodegenDump) |
  0;

COMPILE_ASSERT(0U == static_cast<size_t>(kNone), kNone_not_0);
COMPILE_ASSERT(1U == static_cast<size_t>(kArm), kArm_not_1);
COMPILE_ASSERT(2U == static_cast<size_t>(kArm64), kArm64_not_2);
COMPILE_ASSERT(3U == static_cast<size_t>(kThumb2), kThumb2_not_3);
COMPILE_ASSERT(4U == static_cast<size_t>(kX86), kX86_not_4);
COMPILE_ASSERT(5U == static_cast<size_t>(kX86_64), kX86_64_not_5);
COMPILE_ASSERT(6U == static_cast<size_t>(kMips), kMips_not_6);
COMPILE_ASSERT(7U == static_cast<size_t>(kMips64), kMips64_not_7);

// Additional disabled optimizations (over generally disabled) per instruction set.
static constexpr uint32_t kDisabledOptimizationsPerISA[] = {
    // 0 = kNone.
    ~0U,
    // 1 = kArm, unused (will use kThumb2).
    ~0U,
    // 2 = kArm64.     TODO(Arm64): enable optimizations once backend is mature enough.
    (1 << kLoadStoreElimination) |
    0,
    // 3 = kThumb2.
    0,
    // 4 = kX86.
    0,
    // 5 = kX86_64.
    (1 << kLoadStoreElimination) |
    0,
    // 6 = kMips.
    (1 << kLoadStoreElimination) |
    (1 << kLoadHoisting) |
    (1 << kSuppressLoads) |
    (1 << kNullCheckElimination) |
    (1 << kPromoteRegs) |
    (1 << kTrackLiveTemps) |
    (1 << kSafeOptimizations) |
    (1 << kBBOpt) |
    (1 << kMatch) |
    (1 << kPromoteCompilerTemps) |
    0,
    // 7 = kMips64.
    ~0U
};
COMPILE_ASSERT(sizeof(kDisabledOptimizationsPerISA) == 8 * sizeof(uint32_t), kDisabledOpts_unexp);

// Supported shorty types per instruction set. nullptr means that all are available.
// Z : boolean
// B : byte
// S : short
// C : char
// I : int
// J : long
// F : float
// D : double
// L : reference(object, array)
// V : void
static const char* kSupportedTypes[] = {
    // 0 = kNone.
    "",
    // 1 = kArm, unused (will use kThumb2).
    "",
    // 2 = kArm64.
    nullptr,
    // 3 = kThumb2.
    nullptr,
    // 4 = kX86.
    nullptr,
    // 5 = kX86_64.
    nullptr,
    // 6 = kMips.
    nullptr,
    // 7 = kMips64.
    ""
};
COMPILE_ASSERT(sizeof(kSupportedTypes) == 8 * sizeof(char*), kSupportedTypes_unexp);

static int kAllOpcodes[] = {
    Instruction::NOP,
    Instruction::MOVE,
    Instruction::MOVE_FROM16,
    Instruction::MOVE_16,
    Instruction::MOVE_WIDE,
    Instruction::MOVE_WIDE_FROM16,
    Instruction::MOVE_WIDE_16,
    Instruction::MOVE_OBJECT,
    Instruction::MOVE_OBJECT_FROM16,
    Instruction::MOVE_OBJECT_16,
    Instruction::MOVE_RESULT,
    Instruction::MOVE_RESULT_WIDE,
    Instruction::MOVE_RESULT_OBJECT,
    Instruction::MOVE_EXCEPTION,
    Instruction::RETURN_VOID,
    Instruction::RETURN,
    Instruction::RETURN_WIDE,
    Instruction::RETURN_OBJECT,
    Instruction::CONST_4,
    Instruction::CONST_16,
    Instruction::CONST,
    Instruction::CONST_HIGH16,
    Instruction::CONST_WIDE_16,
    Instruction::CONST_WIDE_32,
    Instruction::CONST_WIDE,
    Instruction::CONST_WIDE_HIGH16,
    Instruction::CONST_STRING,
    Instruction::CONST_STRING_JUMBO,
    Instruction::CONST_CLASS,
    Instruction::MONITOR_ENTER,
    Instruction::MONITOR_EXIT,
    Instruction::CHECK_CAST,
    Instruction::INSTANCE_OF,
    Instruction::ARRAY_LENGTH,
    Instruction::NEW_INSTANCE,
    Instruction::NEW_ARRAY,
    Instruction::FILLED_NEW_ARRAY,
    Instruction::FILLED_NEW_ARRAY_RANGE,
    Instruction::FILL_ARRAY_DATA,
    Instruction::THROW,
    Instruction::GOTO,
    Instruction::GOTO_16,
    Instruction::GOTO_32,
    Instruction::PACKED_SWITCH,
    Instruction::SPARSE_SWITCH,
    Instruction::CMPL_FLOAT,
    Instruction::CMPG_FLOAT,
    Instruction::CMPL_DOUBLE,
    Instruction::CMPG_DOUBLE,
    Instruction::CMP_LONG,
    Instruction::IF_EQ,
    Instruction::IF_NE,
    Instruction::IF_LT,
    Instruction::IF_GE,
    Instruction::IF_GT,
    Instruction::IF_LE,
    Instruction::IF_EQZ,
    Instruction::IF_NEZ,
    Instruction::IF_LTZ,
    Instruction::IF_GEZ,
    Instruction::IF_GTZ,
    Instruction::IF_LEZ,
    Instruction::UNUSED_3E,
    Instruction::UNUSED_3F,
    Instruction::UNUSED_40,
    Instruction::UNUSED_41,
    Instruction::UNUSED_42,
    Instruction::UNUSED_43,
    Instruction::AGET,
    Instruction::AGET_WIDE,
    Instruction::AGET_OBJECT,
    Instruction::AGET_BOOLEAN,
    Instruction::AGET_BYTE,
    Instruction::AGET_CHAR,
    Instruction::AGET_SHORT,
    Instruction::APUT,
    Instruction::APUT_WIDE,
    Instruction::APUT_OBJECT,
    Instruction::APUT_BOOLEAN,
    Instruction::APUT_BYTE,
    Instruction::APUT_CHAR,
    Instruction::APUT_SHORT,
    Instruction::IGET,
    Instruction::IGET_WIDE,
    Instruction::IGET_OBJECT,
    Instruction::IGET_BOOLEAN,
    Instruction::IGET_BYTE,
    Instruction::IGET_CHAR,
    Instruction::IGET_SHORT,
    Instruction::IPUT,
    Instruction::IPUT_WIDE,
    Instruction::IPUT_OBJECT,
    Instruction::IPUT_BOOLEAN,
    Instruction::IPUT_BYTE,
    Instruction::IPUT_CHAR,
    Instruction::IPUT_SHORT,
    Instruction::SGET,
    Instruction::SGET_WIDE,
    Instruction::SGET_OBJECT,
    Instruction::SGET_BOOLEAN,
    Instruction::SGET_BYTE,
    Instruction::SGET_CHAR,
    Instruction::SGET_SHORT,
    Instruction::SPUT,
    Instruction::SPUT_WIDE,
    Instruction::SPUT_OBJECT,
    Instruction::SPUT_BOOLEAN,
    Instruction::SPUT_BYTE,
    Instruction::SPUT_CHAR,
    Instruction::SPUT_SHORT,
    Instruction::INVOKE_VIRTUAL,
    Instruction::INVOKE_SUPER,
    Instruction::INVOKE_DIRECT,
    Instruction::INVOKE_STATIC,
    Instruction::INVOKE_INTERFACE,
    Instruction::RETURN_VOID_BARRIER,
    Instruction::INVOKE_VIRTUAL_RANGE,
    Instruction::INVOKE_SUPER_RANGE,
    Instruction::INVOKE_DIRECT_RANGE,
    Instruction::INVOKE_STATIC_RANGE,
    Instruction::INVOKE_INTERFACE_RANGE,
    Instruction::UNUSED_79,
    Instruction::UNUSED_7A,
    Instruction::NEG_INT,
    Instruction::NOT_INT,
    Instruction::NEG_LONG,
    Instruction::NOT_LONG,
    Instruction::NEG_FLOAT,
    Instruction::NEG_DOUBLE,
    Instruction::INT_TO_LONG,
    Instruction::INT_TO_FLOAT,
    Instruction::INT_TO_DOUBLE,
    Instruction::LONG_TO_INT,
    Instruction::LONG_TO_FLOAT,
    Instruction::LONG_TO_DOUBLE,
    Instruction::FLOAT_TO_INT,
    Instruction::FLOAT_TO_LONG,
    Instruction::FLOAT_TO_DOUBLE,
    Instruction::DOUBLE_TO_INT,
    Instruction::DOUBLE_TO_LONG,
    Instruction::DOUBLE_TO_FLOAT,
    Instruction::INT_TO_BYTE,
    Instruction::INT_TO_CHAR,
    Instruction::INT_TO_SHORT,
    Instruction::ADD_INT,
    Instruction::SUB_INT,
    Instruction::MUL_INT,
    Instruction::DIV_INT,
    Instruction::REM_INT,
    Instruction::AND_INT,
    Instruction::OR_INT,
    Instruction::XOR_INT,
    Instruction::SHL_INT,
    Instruction::SHR_INT,
    Instruction::USHR_INT,
    Instruction::ADD_LONG,
    Instruction::SUB_LONG,
    Instruction::MUL_LONG,
    Instruction::DIV_LONG,
    Instruction::REM_LONG,
    Instruction::AND_LONG,
    Instruction::OR_LONG,
    Instruction::XOR_LONG,
    Instruction::SHL_LONG,
    Instruction::SHR_LONG,
    Instruction::USHR_LONG,
    Instruction::ADD_FLOAT,
    Instruction::SUB_FLOAT,
    Instruction::MUL_FLOAT,
    Instruction::DIV_FLOAT,
    Instruction::REM_FLOAT,
    Instruction::ADD_DOUBLE,
    Instruction::SUB_DOUBLE,
    Instruction::MUL_DOUBLE,
    Instruction::DIV_DOUBLE,
    Instruction::REM_DOUBLE,
    Instruction::ADD_INT_2ADDR,
    Instruction::SUB_INT_2ADDR,
    Instruction::MUL_INT_2ADDR,
    Instruction::DIV_INT_2ADDR,
    Instruction::REM_INT_2ADDR,
    Instruction::AND_INT_2ADDR,
    Instruction::OR_INT_2ADDR,
    Instruction::XOR_INT_2ADDR,
    Instruction::SHL_INT_2ADDR,
    Instruction::SHR_INT_2ADDR,
    Instruction::USHR_INT_2ADDR,
    Instruction::ADD_LONG_2ADDR,
    Instruction::SUB_LONG_2ADDR,
    Instruction::MUL_LONG_2ADDR,
    Instruction::DIV_LONG_2ADDR,
    Instruction::REM_LONG_2ADDR,
    Instruction::AND_LONG_2ADDR,
    Instruction::OR_LONG_2ADDR,
    Instruction::XOR_LONG_2ADDR,
    Instruction::SHL_LONG_2ADDR,
    Instruction::SHR_LONG_2ADDR,
    Instruction::USHR_LONG_2ADDR,
    Instruction::ADD_FLOAT_2ADDR,
    Instruction::SUB_FLOAT_2ADDR,
    Instruction::MUL_FLOAT_2ADDR,
    Instruction::DIV_FLOAT_2ADDR,
    Instruction::REM_FLOAT_2ADDR,
    Instruction::ADD_DOUBLE_2ADDR,
    Instruction::SUB_DOUBLE_2ADDR,
    Instruction::MUL_DOUBLE_2ADDR,
    Instruction::DIV_DOUBLE_2ADDR,
    Instruction::REM_DOUBLE_2ADDR,
    Instruction::ADD_INT_LIT16,
    Instruction::RSUB_INT,
    Instruction::MUL_INT_LIT16,
    Instruction::DIV_INT_LIT16,
    Instruction::REM_INT_LIT16,
    Instruction::AND_INT_LIT16,
    Instruction::OR_INT_LIT16,
    Instruction::XOR_INT_LIT16,
    Instruction::ADD_INT_LIT8,
    Instruction::RSUB_INT_LIT8,
    Instruction::MUL_INT_LIT8,
    Instruction::DIV_INT_LIT8,
    Instruction::REM_INT_LIT8,
    Instruction::AND_INT_LIT8,
    Instruction::OR_INT_LIT8,
    Instruction::XOR_INT_LIT8,
    Instruction::SHL_INT_LIT8,
    Instruction::SHR_INT_LIT8,
    Instruction::USHR_INT_LIT8,
    Instruction::IGET_QUICK,
    Instruction::IGET_WIDE_QUICK,
    Instruction::IGET_OBJECT_QUICK,
    Instruction::IPUT_QUICK,
    Instruction::IPUT_WIDE_QUICK,
    Instruction::IPUT_OBJECT_QUICK,
    Instruction::INVOKE_VIRTUAL_QUICK,
    Instruction::INVOKE_VIRTUAL_RANGE_QUICK,
    Instruction::UNUSED_EB,
    Instruction::UNUSED_EC,
    Instruction::UNUSED_ED,
    Instruction::UNUSED_EE,
    Instruction::UNUSED_EF,
    Instruction::UNUSED_F0,
    Instruction::UNUSED_F1,
    Instruction::UNUSED_F2,
    Instruction::UNUSED_F3,
    Instruction::UNUSED_F4,
    Instruction::UNUSED_F5,
    Instruction::UNUSED_F6,
    Instruction::UNUSED_F7,
    Instruction::UNUSED_F8,
    Instruction::UNUSED_F9,
    Instruction::UNUSED_FA,
    Instruction::UNUSED_FB,
    Instruction::UNUSED_FC,
    Instruction::UNUSED_FD,
    Instruction::UNUSED_FE,
    Instruction::UNUSED_FF,
    // ----- ExtendedMIROpcode -----
    kMirOpPhi,
    kMirOpCopy,
    kMirOpFusedCmplFloat,
    kMirOpFusedCmpgFloat,
    kMirOpFusedCmplDouble,
    kMirOpFusedCmpgDouble,
    kMirOpFusedCmpLong,
    kMirOpNop,
    kMirOpNullCheck,
    kMirOpRangeCheck,
    kMirOpDivZeroCheck,
    kMirOpCheck,
    kMirOpCheckPart2,
    kMirOpSelect,
};

// Unsupported opcodes. nullptr can be used when everything is supported. Size of the lists is
// recorded below.
static const int* kUnsupportedOpcodes[] = {
    // 0 = kNone.
    kAllOpcodes,
    // 1 = kArm, unused (will use kThumb2).
    kAllOpcodes,
    // 2 = kArm64.
    nullptr,
    // 3 = kThumb2.
    nullptr,
    // 4 = kX86.
    nullptr,
    // 5 = kX86_64.
    nullptr,
    // 6 = kMips.
    nullptr,
    // 7 = kMips64.
    kAllOpcodes
};
COMPILE_ASSERT(sizeof(kUnsupportedOpcodes) == 8 * sizeof(int*), kUnsupportedOpcodes_unexp);

// Size of the arrays stored above.
static const size_t kUnsupportedOpcodesSize[] = {
    // 0 = kNone.
    arraysize(kAllOpcodes),
    // 1 = kArm, unused (will use kThumb2).
    arraysize(kAllOpcodes),
    // 2 = kArm64.
    0,
    // 3 = kThumb2.
    0,
    // 4 = kX86.
    0,
    // 5 = kX86_64.
    0,
    // 6 = kMips.
    0,
    // 7 = kMips64.
    arraysize(kAllOpcodes),
};
COMPILE_ASSERT(sizeof(kUnsupportedOpcodesSize) == 8 * sizeof(size_t),
               kUnsupportedOpcodesSize_unexp);

// The maximum amount of Dalvik register in a method for which we will start compiling. Tries to
// avoid an abort when we need to manage more SSA registers than we can.
static constexpr size_t kMaxAllowedDalvikRegisters = INT16_MAX / 2;

CompilationUnit::CompilationUnit(ArenaPool* pool)
  : compiler_driver(nullptr),
    class_linker(nullptr),
    dex_file(nullptr),
    class_loader(nullptr),
    class_def_idx(0),
    method_idx(0),
    code_item(nullptr),
    access_flags(0),
    invoke_type(kDirect),
    shorty(nullptr),
    disable_opt(0),
    enable_debug(0),
    verbose(false),
    compiler(nullptr),
    instruction_set(kNone),
    target64(false),
    num_dalvik_registers(0),
    insns(nullptr),
    num_ins(0),
    num_outs(0),
    num_regs(0),
    compiler_flip_match(false),
    arena(pool),
    arena_stack(pool),
    mir_graph(nullptr),
    cg(nullptr),
    timings("QuickCompiler", true, false),
    print_pass(false) {
}

CompilationUnit::~CompilationUnit() {
}

void CompilationUnit::StartTimingSplit(const char* label) {
  if (compiler_driver->GetDumpPasses()) {
    timings.StartTiming(label);
  }
}

void CompilationUnit::NewTimingSplit(const char* label) {
  if (compiler_driver->GetDumpPasses()) {
    timings.EndTiming();
    timings.StartTiming(label);
  }
}

void CompilationUnit::EndTiming() {
  if (compiler_driver->GetDumpPasses()) {
    timings.EndTiming();
    if (enable_debug & (1 << kDebugTimings)) {
      LOG(INFO) << "TIMINGS " << PrettyMethod(method_idx, *dex_file);
      LOG(INFO) << Dumpable<TimingLogger>(timings);
    }
  }
}

static bool CanCompileShorty(const char* shorty, InstructionSet instruction_set) {
  const char* supported_types = kSupportedTypes[instruction_set];
  if (supported_types == nullptr) {
    // Everything available.
    return true;
  }

  uint32_t shorty_size = strlen(shorty);
  CHECK_GE(shorty_size, 1u);

  for (uint32_t i = 0; i < shorty_size; i++) {
    if (strchr(supported_types, shorty[i]) == nullptr) {
      return false;
    }
  }
  return true;
};

// Skip the method that we do not support currently.
static bool CanCompileMethod(uint32_t method_idx, const DexFile& dex_file,
                             CompilationUnit& cu) {
  // This is a limitation in mir_graph. See MirGraph::SetNumSSARegs.
  if (cu.num_dalvik_registers > kMaxAllowedDalvikRegisters) {
    VLOG(compiler) << "Too many dalvik registers : " << cu.num_dalvik_registers;
    return false;
  }

  // Check whether we do have limitations at all.
  if (kSupportedTypes[cu.instruction_set] == nullptr &&
      kUnsupportedOpcodesSize[cu.instruction_set] == 0U) {
    return true;
  }

  // Check if we can compile the prototype.
  const char* shorty = dex_file.GetMethodShorty(dex_file.GetMethodId(method_idx));
  if (!CanCompileShorty(shorty, cu.instruction_set)) {
    VLOG(compiler) << "Unsupported shorty : " << shorty;
    return false;
  }

  const int *unsupport_list = kUnsupportedOpcodes[cu.instruction_set];
  int unsupport_list_size = kUnsupportedOpcodesSize[cu.instruction_set];

  for (unsigned int idx = 0; idx < cu.mir_graph->GetNumBlocks(); idx++) {
    BasicBlock* bb = cu.mir_graph->GetBasicBlock(idx);
    if (bb == NULL) continue;
    if (bb->block_type == kDead) continue;
    for (MIR* mir = bb->first_mir_insn; mir != nullptr; mir = mir->next) {
      int opcode = mir->dalvikInsn.opcode;
      // Check if we support the byte code.
      if (std::find(unsupport_list, unsupport_list + unsupport_list_size,
                    opcode) != unsupport_list + unsupport_list_size) {
        if (!MIR::DecodedInstruction::IsPseudoMirOp(opcode)) {
          VLOG(compiler) << "Unsupported dalvik byte code : "
              << mir->dalvikInsn.opcode;
        } else {
          VLOG(compiler) << "Unsupported extended MIR opcode : "
              << MIRGraph::extended_mir_op_names_[opcode - kMirOpFirst];
        }
        return false;
      }
      // Check if it invokes a prototype that we cannot support.
      if (Instruction::INVOKE_VIRTUAL == opcode ||
          Instruction::INVOKE_SUPER == opcode ||
          Instruction::INVOKE_DIRECT == opcode ||
          Instruction::INVOKE_STATIC == opcode ||
          Instruction::INVOKE_INTERFACE == opcode) {
        uint32_t invoke_method_idx = mir->dalvikInsn.vB;
        const char* invoke_method_shorty = dex_file.GetMethodShorty(
            dex_file.GetMethodId(invoke_method_idx));
        if (!CanCompileShorty(invoke_method_shorty, cu.instruction_set)) {
          VLOG(compiler) << "Unsupported to invoke '"
              << PrettyMethod(invoke_method_idx, dex_file)
              << "' with shorty : " << invoke_method_shorty;
          return false;
        }
      }
    }
  }
  return true;
}

static CompiledMethod* CompileMethod(CompilerDriver& driver,
                                     Compiler* compiler,
                                     const DexFile::CodeItem* code_item,
                                     uint32_t access_flags, InvokeType invoke_type,
                                     uint16_t class_def_idx, uint32_t method_idx,
                                     jobject class_loader, const DexFile& dex_file,
                                     void* llvm_compilation_unit) {
  std::string method_name = PrettyMethod(method_idx, dex_file);
  VLOG(compiler) << "Compiling " << method_name << "...";
  if (code_item->insns_size_in_code_units_ >= 0x10000) {
    LOG(INFO) << "Method size exceeds compiler limits: " << code_item->insns_size_in_code_units_
              << " in " << method_name;
    return NULL;
  }

  if (!driver.GetCompilerOptions().IsCompilationEnabled()) {
    return nullptr;
  }

  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
  CompilationUnit cu(driver.GetArenaPool());

  cu.compiler_driver = &driver;
  cu.class_linker = class_linker;
  cu.instruction_set = driver.GetInstructionSet();
  if (cu.instruction_set == kArm) {
    cu.instruction_set = kThumb2;
  }
  cu.target64 = Is64BitInstructionSet(cu.instruction_set);
  cu.compiler = compiler;
  // TODO: Mips64 is not yet implemented.
  CHECK((cu.instruction_set == kThumb2) ||
        (cu.instruction_set == kArm64) ||
        (cu.instruction_set == kX86) ||
        (cu.instruction_set == kX86_64) ||
        (cu.instruction_set == kMips));

  /* Adjust this value accordingly once inlining is performed */
  cu.num_dalvik_registers = code_item->registers_size_;
  // TODO: set this from command line
  cu.compiler_flip_match = false;
  bool use_match = !cu.compiler_method_match.empty();
  bool match = use_match && (cu.compiler_flip_match ^
      (method_name.find(cu.compiler_method_match) != std::string::npos));
  if (!use_match || match) {
    cu.disable_opt = kCompilerOptimizerDisableFlags;
    cu.enable_debug = kCompilerDebugFlags;
    cu.verbose = VLOG_IS_ON(compiler) ||
        (cu.enable_debug & (1 << kDebugVerbose));
  }

  if (gVerboseMethods.size() != 0) {
    cu.verbose = false;
    for (size_t i = 0; i < gVerboseMethods.size(); ++i) {
      if (method_name.find(gVerboseMethods[i])
          != std::string::npos) {
        cu.verbose = true;
        break;
      }
    }
  }

  if (cu.verbose) {
    cu.enable_debug |= (1 << kDebugCodegenDump);
  }

  /*
   * TODO: rework handling of optimization and debug flags.  Should we split out
   * MIR and backend flags?  Need command-line setting as well.
   */

  compiler->InitCompilationUnit(cu);

  // Disable optimizations according to instruction set.
  cu.disable_opt |= kDisabledOptimizationsPerISA[cu.instruction_set];

  cu.StartTimingSplit("BuildMIRGraph");
  cu.mir_graph.reset(new MIRGraph(&cu, &cu.arena));

  /*
   * After creation of the MIR graph, also create the code generator.
   * The reason we do this is that optimizations on the MIR graph may need to get information
   * that is only available if a CG exists.
   */
  cu.cg.reset(compiler->GetCodeGenerator(&cu, llvm_compilation_unit));

  /* Gathering opcode stats? */
  if (kCompilerDebugFlags & (1 << kDebugCountOpcodes)) {
    cu.mir_graph->EnableOpcodeCounting();
  }

  /* Build the raw MIR graph */
  cu.mir_graph->InlineMethod(code_item, access_flags, invoke_type, class_def_idx, method_idx,
                              class_loader, dex_file);

  if (!CanCompileMethod(method_idx, dex_file, cu)) {
    VLOG(compiler)  << cu.instruction_set << ": Cannot compile method : " << method_name;
    return nullptr;
  }

  cu.NewTimingSplit("MIROpt:CheckFilters");
  std::string skip_message;
  if (cu.mir_graph->SkipCompilation(&skip_message)) {
    VLOG(compiler) << cu.instruction_set << ": Skipping method : "
                   << method_name << "  Reason = " << skip_message;
    return nullptr;
  }

  /* Create the pass driver and launch it */
  PassDriverMEOpts pass_driver(&cu);
  pass_driver.Launch();

  /* For non-leaf methods check if we should skip compilation when the profiler is enabled. */
  if (cu.compiler_driver->ProfilePresent()
      && !cu.mir_graph->MethodIsLeaf()
      && cu.mir_graph->SkipCompilationByName(method_name)) {
    return nullptr;
  }

  if (cu.enable_debug & (1 << kDebugDumpCheckStats)) {
    cu.mir_graph->DumpCheckStats();
  }

  if (kCompilerDebugFlags & (1 << kDebugCountOpcodes)) {
    cu.mir_graph->ShowOpcodeStats();
  }

  /* Reassociate sreg names with original Dalvik vreg names. */
  cu.mir_graph->RemapRegLocations();

  /* Free Arenas from the cu.arena_stack for reuse by the cu.arena in the codegen. */
  if (cu.enable_debug & (1 << kDebugShowMemoryUsage)) {
    if (cu.arena_stack.PeakBytesAllocated() > 256 * 1024) {
      MemStats stack_stats(cu.arena_stack.GetPeakStats());
      LOG(INFO) << method_name << " " << Dumpable<MemStats>(stack_stats);
    }
  }
  cu.arena_stack.Reset();

  CompiledMethod* result = NULL;

  if (cu.mir_graph->PuntToInterpreter()) {
    VLOG(compiler) << cu.instruction_set << ": Punted method to interpreter: " << method_name;
    return nullptr;
  }

  cu.cg->Materialize();

  cu.NewTimingSplit("Dedupe");  /* deduping takes up the vast majority of time in GetCompiledMethod(). */
  result = cu.cg->GetCompiledMethod();
  cu.NewTimingSplit("Cleanup");

  if (result) {
    VLOG(compiler) << cu.instruction_set << ": Compiled " << method_name;
  } else {
    VLOG(compiler) << cu.instruction_set << ": Deferred " << method_name;
  }

  if (cu.enable_debug & (1 << kDebugShowMemoryUsage)) {
    if (cu.arena.BytesAllocated() > (1 * 1024 *1024)) {
      MemStats mem_stats(cu.arena.GetMemStats());
      LOG(INFO) << method_name << " " << Dumpable<MemStats>(mem_stats);
    }
  }

  if (cu.enable_debug & (1 << kDebugShowSummaryMemoryUsage)) {
    LOG(INFO) << "MEMINFO " << cu.arena.BytesAllocated() << " " << cu.mir_graph->GetNumBlocks()
              << " " << method_name;
  }

  cu.EndTiming();
  driver.GetTimingsLogger()->AddLogger(cu.timings);
  return result;
}

CompiledMethod* CompileOneMethod(CompilerDriver& driver,
                                 Compiler* compiler,
                                 const DexFile::CodeItem* code_item,
                                 uint32_t access_flags,
                                 InvokeType invoke_type,
                                 uint16_t class_def_idx,
                                 uint32_t method_idx,
                                 jobject class_loader,
                                 const DexFile& dex_file,
                                 void* compilation_unit) {
  return CompileMethod(driver, compiler, code_item, access_flags, invoke_type, class_def_idx,
                       method_idx, class_loader, dex_file, compilation_unit);
}

}  // namespace art

extern "C" art::CompiledMethod*
    ArtQuickCompileMethod(art::CompilerDriver& driver,
                          const art::DexFile::CodeItem* code_item,
                          uint32_t access_flags, art::InvokeType invoke_type,
                          uint16_t class_def_idx, uint32_t method_idx, jobject class_loader,
                          const art::DexFile& dex_file) {
  // TODO: check method fingerprint here to determine appropriate backend type.  Until then, use
  // build default.
  art::Compiler* compiler = driver.GetCompiler();
  return art::CompileOneMethod(driver, compiler, code_item, access_flags, invoke_type,
                               class_def_idx, method_idx, class_loader, dex_file,
                               NULL /* use thread llvm_info */);
}