[Courgette] AssemblyProgram: Serialize data to single raw buffer, instead of storing pointer of obj…

courgette/assembly_program.cc

Index: courgette/assembly_program.cc
diff --git a/courgette/assembly_program.cc b/courgette/assembly_program.cc
index f1502a9ee324e956f034578b1776e9afc3aa29fd..1eb267a0c1696a1e6b8b86af3fc36da0c33abdd2 100644
--- a/courgette/assembly_program.cc
+++ b/courgette/assembly_program.cc
@@ -21,93 +21,286 @@ namespace courgette {
 
 namespace {
 
-// Sets the current address for the emitting instructions.
-class OriginInstruction : public Instruction {
+// AssemblyProgram stores a sequence of instructions. The main uses are:
+// - Serialization (write): InstructionStoreReceptor::Emit*() produces and
+//   serializes instructions into AssemblyProgram::instruction_raw_data_.
+// - Encode (read): AssemblyProgram::Encode() iterates over serialized
+//   instructions and sends them to EncodedProgram.
+// - Label extraction (read): AssemblyProgram::HandleInstructionLabels()
+//   iterates over serialized instructions and process only instructions with
+//   Labels.
+
+/******** Instruction ********/
+
+// Each instruction type (AssemblyOp::OP) has a corresponding class, and these
+// classes have a common base class (Instruction). To simplify serialization,
+// we want to write entire objects into buffer using pointer casting. However,
+// the naive approach has 2 problems:
+// (1) C++ struct can add padding, which wastes space.
+// (2) Virtual function usage adds bloat to object size.
+// Problem (1) is solved using #pragma pack() directives. Problem 2 is solved
+// by decoupling storage (Data* structs) from behavior (Instruction* classes).
+
+// Instruction interfaces that don't use templates. Instead of directly storing
+// data, Instruction provides a "view" into a provided buffer, and keeps a
+// "cursor" pointer to access the data. The base interface is only used by
+// "read" use cases (encode & label extraction).
+class Instruction {
  public:
-  explicit OriginInstruction(RVA rva) : Instruction(ORIGIN, 0), rva_(rva) {}
-  RVA origin_rva() const { return rva_; }
+  Instruction() = default;
+  virtual ~Instruction() = default;
+
+// All data payload for inherited classes of Instruction.
+#pragma pack(push, 1)
+  // If we nest these classes then we won't be able to use initializer list.
+  struct Data {
+    AssemblyOp::OP op;
+  };
+
+  struct DataWithRVA {
+    AssemblyOp::OP op;
+    RVA rva;
+  };
+
+  struct DataWithExecutableType {
+    AssemblyOp::OP op;
+    ExecutableType exe_type;
+  };
+
+  struct DataWithByte {
+    AssemblyOp::OP op;
+    uint8_t byte;
+  };
+
+  struct DataWithBytesAndSize {
+    AssemblyOp::OP op;
+    const uint8_t* bytes;
+    serialized_size_t size;
+  };
+
+  struct DataWithLabel {
+    AssemblyOp::OP op;
+    Label* label;
+  };
+
+  struct DataWithLabelAndARMRel32 {
+    AssemblyOp::OP op;
+    Label* label;
+    uint16_t compressed_op;
+    const uint8_t* arm_op;  // TODO(huangs): Looks unused? Remove.
+    uint16_t op_size;       // TODO(huangs): Looks unused? Remove.
+  };
+#pragma pack(pop)
+
+  // Getters for basic info.
+  virtual AssemblyOp::OP GetOp() const = 0;
+  virtual size_t GetSize() const = 0;
+
+  // If the instruction located at |it| has a Label, returns it. Otherwise
+  // returns null.
+  virtual Label* ReadLabel(AssemblyRawDataVector::const_iterator it) const {
+    return nullptr;
+  }
+
+  // Sends the instruction to |encoded|, possibly using config from |prog|.
+  virtual bool Encode(AssemblyRawDataVector::const_iterator it,
+                      EncodedProgram* encoded) const = 0;
+
  private:
-  RVA  rva_;
+  DISALLOW_COPY_AND_ASSIGN(Instruction);
 };
 
-// Emits an entire PE base relocation table.
-class PeRelocsInstruction : public Instruction {
- public:
-  PeRelocsInstruction() : Instruction(MAKEPERELOCS) {}
-};
+/******** InstructionImpl ********/
 
-// Emits an ELF relocation table.
-class ElfRelocsInstruction : public Instruction {
+// Intermediate Instruction class using templates.
+template <int OP_USE, typename DATA_T>
+class InstructionImpl : public Instruction {
  public:
-  ElfRelocsInstruction() : Instruction(MAKEELFRELOCS) {}
-};
+  using This = InstructionImpl<OP_USE, DATA_T>;
+
+  static constexpr AssemblyOp::OP kOpUse = static_cast<AssemblyOp::OP>(OP_USE);
+  static constexpr size_t kSize = sizeof(DATA_T);
+
+  InstructionImpl() {}
+  ~InstructionImpl() override = default;
+
+  // Instruction:
+  AssemblyOp::OP GetOp() const override { return kOpUse; }
+  size_t GetSize() const override { return kSize; }
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override = 0;
+
+  // Allocates space at end of |raw_data|, and writes |data_in| there.
+  CheckBool Serialize(AssemblyRawDataVector* raw_data, DATA_T data_in) {
+    size_t pos = raw_data->size();
+    if (!raw_data->resize(pos + kSize, 0))
+      return false;
+    DCHECK(pos + sizeof(DATA_T) <= raw_data->size());
+    *reinterpret_cast<DATA_T*>(&(*raw_data)[pos]) = data_in;
+    return true;
+  }
 
-// Emits an ELF ARM relocation table.
-class ElfARMRelocsInstruction : public Instruction {
- public:
-  ElfARMRelocsInstruction() : Instruction(MAKEELFARMRELOCS) {}
+ protected:
+  const DATA_T* SeekRead(AssemblyRawDataVector::const_iterator it) const {
+    return reinterpret_cast<const DATA_T*>(&(*it));
+  }
 };
 
-// Emits a single byte.
-class ByteInstruction : public Instruction {
- public:
-  explicit ByteInstruction(uint8_t value) : Instruction(DEFBYTE, value) {}
-  uint8_t byte_value() const { return info_; }
+/******** InstructionWithLabel ********/
+
+// Common code for the "Label extraction" use case.
+template <int OP_USE, typename DATA_T>
+class InstructionWithLabel : public InstructionImpl<OP_USE, DATA_T> {
+  // Instruction:
+  Label* ReadLabel(AssemblyRawDataVector::const_iterator it) const override {
+    return SeekRead(it)->label;
+  }
 };
 
-// Emits a single byte.
-class BytesInstruction : public Instruction {
- public:
-  BytesInstruction(const uint8_t* values, size_t len)
-      : Instruction(DEFBYTES, 0), values_(values), len_(len) {}
-  const uint8_t* byte_values() const { return values_; }
-  size_t len() const { return len_; }
+/******** Instruction*, one for each AssemblyOp:OP value ********/
 
- private:
-  const uint8_t* values_;
-  size_t len_;
+struct InstructionMakePERelocs
+    : public InstructionImpl<AssemblyOp::MAKEPERELOCS,
+                             Instruction::DataWithExecutableType> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddPeMakeRelocs(SeekRead(it)->exe_type);
+  }
+  static InstructionMakePERelocs instance;
 };
+InstructionMakePERelocs InstructionMakePERelocs::instance;
 
-// A ABS32 to REL32 instruction emits a reference to a label's address.
-class InstructionWithLabel : public Instruction {
- public:
-  InstructionWithLabel(OP op, Label* label)
-    : Instruction(op, 0), label_(label) {
-    if (label == NULL) NOTREACHED();
+struct InstructionMakeELFRelocs
+    : public InstructionImpl<AssemblyOp::MAKEELFRELOCS, Instruction::Data> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddElfMakeRelocs();
   }
-  Label* label() const { return label_; }
- protected:
-  Label* label_;
+  static InstructionMakeELFRelocs instance;
 };
+InstructionMakeELFRelocs InstructionMakeELFRelocs::instance;
 
-// An ARM REL32 instruction emits a reference to a label's address and
-// a specially-compressed ARM op.
-class InstructionWithLabelARM : public InstructionWithLabel {
- public:
-  InstructionWithLabelARM(OP op,
-                          uint16_t compressed_op,
-                          Label* label,
-                          const uint8_t* arm_op,
-                          uint16_t op_size)
-      : InstructionWithLabel(op, label),
-        compressed_op_(compressed_op),
-        arm_op_(arm_op),
-        op_size_(op_size) {
-    if (label == NULL) NOTREACHED();
-  }
-  uint16_t compressed_op() const { return compressed_op_; }
-  const uint8_t* arm_op() const { return arm_op_; }
-  uint16_t op_size() const { return op_size_; }
+struct InstructionMakeELFARMRelocs
+    : public InstructionImpl<AssemblyOp::MAKEELFARMRELOCS, Instruction::Data> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddElfARMMakeRelocs();
+  }
+  static InstructionMakeELFARMRelocs instance;
+};
+InstructionMakeELFARMRelocs InstructionMakeELFARMRelocs::instance;
 
- private:
-  uint16_t compressed_op_;
-  const uint8_t* arm_op_;
-  uint16_t op_size_;
+struct InstructionOrigin
+    : public InstructionImpl<AssemblyOp::ORIGIN, Instruction::DataWithRVA> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddOrigin(SeekRead(it)->rva);
+  }
+  static InstructionOrigin instance;
+};
+InstructionOrigin InstructionOrigin::instance;
+
+struct InstructionSingleByte
+    : public InstructionImpl<AssemblyOp::SINGLEBYTE,
+                             Instruction::DataWithByte> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddCopy(1, &SeekRead(it)->byte);
+  }
+  static InstructionSingleByte instance;
+};
+InstructionSingleByte InstructionSingleByte::instance;
+
+struct InstructionMultipleBytes
+    : public InstructionImpl<AssemblyOp::MULTIPLEBYTES,
+                             Instruction::DataWithBytesAndSize> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    const auto* cursor = SeekRead(it);
+    return encoded->AddCopy(cursor->size, cursor->bytes);
+  }
+  static InstructionMultipleBytes instance;
+};
+InstructionMultipleBytes InstructionMultipleBytes::instance;
+
+struct InstructionRel32
+    : public InstructionWithLabel<AssemblyOp::REL32,
+                                  Instruction::DataWithLabel> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddRel32(SeekRead(it)->label->index_);
+  }
+  static InstructionRel32 instance;
+};
+InstructionRel32 InstructionRel32::instance;
+
+struct InstructionRel32ARM
+    : public InstructionWithLabel<AssemblyOp::REL32ARM,
+                                  Instruction::DataWithLabelAndARMRel32> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    const auto* cursor = SeekRead(it);
+    return encoded->AddRel32ARM(cursor->compressed_op, cursor->label->index_);
+  }
+  static InstructionRel32ARM instance;
 };
+InstructionRel32ARM InstructionRel32ARM::instance;
+
+struct InstructionAbs32
+    : public InstructionWithLabel<AssemblyOp::ABS32,
+                                  Instruction::DataWithLabel> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddAbs32(SeekRead(it)->label->index_);
+  }
+  static InstructionAbs32 instance;
+};
+InstructionAbs32 InstructionAbs32::instance;
+
+struct InstructionAbs64
+    : public InstructionWithLabel<AssemblyOp::ABS64,
+                                  Instruction::DataWithLabel> {
+  bool Encode(AssemblyRawDataVector::const_iterator it,
+              EncodedProgram* encoded) const override {
+    return encoded->AddAbs64(SeekRead(it)->label->index_);
+  }
+  static InstructionAbs64 instance;
+};
+InstructionAbs64 InstructionAbs64::instance;
+
+/******** Utility Functions ********/
+
+// A collection of reusable Instruction instances.
+Instruction* FindInstruction(AssemblyOp::OP op) {
+  switch (op) {
+    case InstructionOrigin::kOpUse:
+      return &InstructionOrigin::instance;
+    case InstructionMakePERelocs::kOpUse:
+      return &InstructionMakePERelocs::instance;
+    case InstructionMakeELFRelocs::kOpUse:
+      return &InstructionMakeELFRelocs::instance;
+    case InstructionSingleByte::kOpUse:
+      return &InstructionSingleByte::instance;
+    case InstructionRel32::kOpUse:
+      return &InstructionRel32::instance;
+    case InstructionAbs32::kOpUse:
+      return &InstructionAbs32::instance;
+    case InstructionRel32ARM::kOpUse:
+      return &InstructionRel32ARM::instance;
+    case InstructionMakeELFARMRelocs::kOpUse:
+      return &InstructionMakeELFARMRelocs::instance;
+    case InstructionMultipleBytes::kOpUse:
+      return &InstructionMultipleBytes::instance;
+    case InstructionAbs64::kOpUse:
+      return &InstructionAbs64::instance;
+  }
+  NOTREACHED();
+  return nullptr;
+}
 
 /******** InstructionCountReceptor ********/
 
-// An InstructionReceptor that counts space occupied by emitted instructions.
+// An InstructionReceptor to count space occupied by emitted instructions.
 class InstructionCountReceptor : public InstructionReceptor {
  public:
   InstructionCountReceptor() = default;
@@ -115,26 +308,35 @@ class InstructionCountReceptor : public InstructionReceptor {
   size_t size() const { return size_; }
 
   // InstructionReceptor:
-  // TODO(huangs): 2016/11: Populate these with size_ += ...
-  CheckBool EmitPeRelocs() override { return true; }
-  CheckBool EmitElfRelocation() override { return true; }
-  CheckBool EmitElfARMRelocation() override { return true; }
-  CheckBool EmitOrigin(RVA rva) override { return true; }
-  CheckBool EmitSingleByte(uint8_t byte) override { return true; }
-  CheckBool EmitMultipleBytes(const uint8_t* bytes, size_t len) override {
-    return true;
+  CheckBool EmitPeRelocs() { return Add<InstructionMakePERelocs>(); }
+  CheckBool EmitElfRelocation() { return Add<InstructionMakeELFRelocs>(); }
+  CheckBool EmitElfARMRelocation() {
+    return Add<InstructionMakeELFARMRelocs>();
+  }
+  CheckBool EmitOrigin(RVA rva) { return Add<InstructionOrigin>(); }
+  CheckBool EmitSingleByte(uint8_t byte) {
+    return Add<InstructionSingleByte>();
   }
-  CheckBool EmitRel32(Label* label) override { return true; }
-  CheckBool EmitRel32ARM(uint16_t op,
+  CheckBool EmitMultipleBytes(const uint8_t* bytes, size_t len) {
+    return Add<InstructionMultipleBytes>();
+  }
+  CheckBool EmitRel32(Label* label) { return Add<InstructionRel32>(); }
+  CheckBool EmitRel32ARM(uint16_t compressed_op,
                          Label* label,
                          const uint8_t* arm_op,
-                         uint16_t op_size) override {
-    return true;
+                         uint16_t op_size) {
+    return Add<InstructionRel32ARM>();
   }
-  CheckBool EmitAbs32(Label* label) override { return true; }
-  CheckBool EmitAbs64(Label* label) override { return true; }
+  CheckBool EmitAbs32(Label* label) { return Add<InstructionAbs32>(); }
+  CheckBool EmitAbs64(Label* label) { return Add<InstructionAbs64>(); }
 
  private:
+  template <typename T>
+  inline bool Add() {
+    size_ += T::kSize;
+    return true;
+  }
+
   size_t size_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(InstructionCountReceptor);
@@ -142,50 +344,67 @@ class InstructionCountReceptor : public InstructionReceptor {
 
 /******** InstructionStoreReceptor ********/
 
-// An InstructionReceptor that stores emitted instructions.
+// An InstructionReceptor to store emitted instructions.
 class InstructionStoreReceptor : public InstructionReceptor {
  public:
-  explicit InstructionStoreReceptor(AssemblyProgram* program)
-      : program_(program) {
-    CHECK(program_);
-  }
-
-  // TODO(huangs): 2016/11: Add Reserve().
+  InstructionStoreReceptor(ExecutableType exe_type,
+                           AssemblyRawDataVector* raw_data)
+      : exe_type_(exe_type), raw_data_(raw_data) {}
 
   // InstructionReceptor:
-  // TODO(huangs): 2016/11: Replace stub with implementation.
-  CheckBool EmitPeRelocs() override { return program_->EmitPeRelocs(); }
-  CheckBool EmitElfRelocation() override {
-    return program_->EmitElfRelocation();
+  CheckBool EmitPeRelocs() {
+    InstructionMakePERelocs instr;
+    return instr.Serialize(raw_data_, {instr.GetOp(), exe_type_});
+  }
+  CheckBool EmitElfRelocation() {
+    InstructionMakeELFRelocs instr;
+    return instr.Serialize(raw_data_, {instr.GetOp()});
   }
-  CheckBool EmitElfARMRelocation() override {
-    return program_->EmitElfARMRelocation();
+  CheckBool EmitElfARMRelocation() {
+    InstructionMakeELFARMRelocs instr;
+    return instr.Serialize(raw_data_, {instr.GetOp()});
   }
-  CheckBool EmitOrigin(RVA rva) override { return program_->EmitOrigin(rva); }
-  CheckBool EmitSingleByte(uint8_t byte) override {
-    return program_->EmitSingleByte(byte);
+  CheckBool EmitOrigin(RVA rva) {
+    InstructionOrigin instr;
+    return instr.Serialize(raw_data_, {instr.GetOp(), rva});
   }
-  CheckBool EmitMultipleBytes(const uint8_t* bytes, size_t len) override {
-    return program_->EmitMultipleBytes(bytes, len);
+  CheckBool EmitSingleByte(uint8_t byte) {
+    InstructionSingleByte instr;
+    return instr.Serialize(raw_data_, {instr.GetOp(), byte});
   }
-  CheckBool EmitRel32(Label* label) override {
-    return program_->EmitRel32(label);
+  CheckBool EmitMultipleBytes(const uint8_t* bytes, size_t len) {
+    InstructionMultipleBytes instr;
+    return instr.Serialize(
+        raw_data_, {instr.GetOp(), bytes, static_cast<serialized_size_t>(len)});
   }
-  CheckBool EmitRel32ARM(uint16_t op,
+  CheckBool EmitRel32(Label* label) {
+    InstructionRel32 instr;
+    return instr.Serialize(raw_data_, {instr.GetOp(), label});
+  }
+  CheckBool EmitRel32ARM(uint16_t compressed_op,
                          Label* label,
                          const uint8_t* arm_op,
-                         uint16_t op_size) override {
-    return program_->EmitRel32ARM(op, label, arm_op, op_size);
+                         uint16_t op_size) {
+    InstructionRel32ARM instr;
+    // Note that |label| is moved before |compressed_op|.
+    return instr.Serialize(
+        raw_data_, {instr.GetOp(), label, compressed_op, arm_op, op_size});
   }
-  CheckBool EmitAbs32(Label* label) override {
-    return program_->EmitAbs32(label);
+  CheckBool EmitAbs32(Label* label) {
+    InstructionAbs32 instr;
+    return instr.Serialize(raw_data_, {instr.GetOp(), label});
   }
-  CheckBool EmitAbs64(Label* label) override {
-    return program_->EmitAbs64(label);
+  CheckBool EmitAbs64(Label* label) {
+    InstructionAbs64 instr;
+    return instr.Serialize(raw_data_, {instr.GetOp(), label});
   }
 
  private:
-  AssemblyProgram* program_;
+  // Executable type for PE relocation.
+  const ExecutableType exe_type_;
+
+  // Storage of raw instruction data, owned by this instance's owner.
+  AssemblyRawDataVector* raw_data_;
 
   DISALLOW_COPY_AND_ASSIGN(InstructionStoreReceptor);
 };
@@ -194,68 +413,7 @@ class InstructionStoreReceptor : public InstructionReceptor {
 
 /******** AssemblyProgram ********/
 
-AssemblyProgram::AssemblyProgram(ExecutableType kind)
-  : kind_(kind), image_base_(0) {
-}
-
-AssemblyProgram::~AssemblyProgram() {
-  for (size_t i = 0;  i < instructions_.size();  ++i) {
-    Instruction* instruction = instructions_[i];
-    if (instruction->op() != DEFBYTE)  // Owned by byte_instruction_cache_.
-      UncheckedDelete(instruction);
-  }
-  if (byte_instruction_cache_.get()) {
-    for (size_t i = 0;  i < 256;  ++i)
-      UncheckedDelete(byte_instruction_cache_[i]);
-  }
-}
-
-CheckBool AssemblyProgram::EmitPeRelocs() {
-  return Emit(ScopedInstruction(UncheckedNew<PeRelocsInstruction>()));
-}
-
-CheckBool AssemblyProgram::EmitElfRelocation() {
-  return Emit(ScopedInstruction(UncheckedNew<ElfRelocsInstruction>()));
-}
-
-CheckBool AssemblyProgram::EmitElfARMRelocation() {
-  return Emit(ScopedInstruction(UncheckedNew<ElfARMRelocsInstruction>()));
-}
-
-CheckBool AssemblyProgram::EmitOrigin(RVA rva) {
-  return Emit(ScopedInstruction(UncheckedNew<OriginInstruction>(rva)));
-}
-
-CheckBool AssemblyProgram::EmitSingleByte(uint8_t byte) {
-  return EmitShared(GetByteInstruction(byte));
-}
-
-CheckBool AssemblyProgram::EmitMultipleBytes(const uint8_t* bytes, size_t len) {
-  return Emit(ScopedInstruction(UncheckedNew<BytesInstruction>(bytes, len)));
-}
-
-CheckBool AssemblyProgram::EmitRel32(Label* label) {
-  return Emit(
-      ScopedInstruction(UncheckedNew<InstructionWithLabel>(REL32, label)));
-}
-
-CheckBool AssemblyProgram::EmitRel32ARM(uint16_t op,
-                                        Label* label,
-                                        const uint8_t* arm_op,
-                                        uint16_t op_size) {
-  return Emit(ScopedInstruction(UncheckedNew<InstructionWithLabelARM>(
-      REL32ARM, op, label, arm_op, op_size)));
-}
-
-CheckBool AssemblyProgram::EmitAbs32(Label* label) {
-  return Emit(
-      ScopedInstruction(UncheckedNew<InstructionWithLabel>(ABS32, label)));
-}
-
-CheckBool AssemblyProgram::EmitAbs64(Label* label) {
-  return Emit(
-      ScopedInstruction(UncheckedNew<InstructionWithLabel>(ABS64, label)));
-}
+AssemblyProgram::AssemblyProgram(ExecutableType kind) : kind_(kind) {}
 
 void AssemblyProgram::PrecomputeLabels(RvaVisitor* abs32_visitor,
                                        RvaVisitor* rel32_visitor) {
@@ -305,40 +463,45 @@ Label* AssemblyProgram::FindRel32Label(RVA rva) {
 
 void AssemblyProgram::HandleInstructionLabels(
     const AssemblyProgram::LabelHandlerMap& handler_map) const {
-  for (const Instruction* instruction : instructions_) {
-    LabelHandlerMap::const_iterator it = handler_map.find(instruction->op());
-    if (it != handler_map.end()) {
-      it->second.Run(
-          static_cast<const InstructionWithLabel*>(instruction)->label());
+  auto it = instruction_raw_data_.begin();
+  auto end = instruction_raw_data_.end();
+  while (it < end) {
+    // Get the instruction from the operation.
+    AssemblyOp::OP op = static_cast<AssemblyOp::OP>(*it);
+    Instruction* instr = FindInstruction(op);
+    DCHECK_LE(it + instr->GetSize(), end);
+
+    // If Label exists and is handled, then handle it.
+    Label* label = instr->ReadLabel(it);
+    if (label) {
+      LabelHandlerMap::const_iterator label_it = handler_map.find(op);
+      if (label_it != handler_map.end())
+        label_it->second.Run(label);
     }
+    it += instr->GetSize();
   }
 }
 
 CheckBool AssemblyProgram::GenerateInstructions(
     const InstructionGenerator& gen) {
+  CHECK(instruction_raw_data_.empty());
+
   // Pass 1: Count the space needed to store instructions.
   InstructionCountReceptor count_receptor;
   if (!gen.Run(this, &count_receptor))
     return false;
 
-  // Pass 2: Emit all instructions to preallocated buffer (uses Phase 1 count).
-  InstructionStoreReceptor store_receptor(this);
-  // TODO(huangs): 2016/11: Pass |count_receptor_->size()| to |store_receptor_|
-  // to reserve space for raw data.
-  return gen.Run(this, &store_receptor);
-}
+  // Reserve space for raw data, using count from Phase 1.
+  if (!instruction_raw_data_.reserve(count_receptor.size()))
+    return false;
 
-CheckBool AssemblyProgram::Emit(ScopedInstruction instruction) {
-  if (!instruction || !instructions_.push_back(instruction.get()))
+  // Pass 2: Emit all instructions to preallocated buffer (uses Phase 1 count).
+  InstructionStoreReceptor store_receptor(kind(), &instruction_raw_data_);
+  if (!gen.Run(this, &store_receptor))
     return false;
-  // Ownership successfully passed to instructions_.
-  ignore_result(instruction.release());
-  return true;
-}
 
-CheckBool AssemblyProgram::EmitShared(Instruction* instruction) {
-  DCHECK(!instruction || instruction->op() == DEFBYTE);
-  return instruction && instructions_.push_back(instruction);
+  CHECK_EQ(count_receptor.size(), instruction_raw_data_.size());
+  return true;
 }
 
 void AssemblyProgram::UnassignIndexes(RVAToLabel* labels) {
@@ -367,7 +530,7 @@ void AssemblyProgram::AssignRemainingIndexes(RVAToLabel* labels) {
   // An address table compresses best when each index is associated with an
   // address that is slight larger than the previous index.
 
-  // First see which indexes have not been used.  The 'available' vector could
+  // First see which indexes have not been used. The 'available' vector could
   // grow even bigger, but the number of addresses is a better starting size
   // than empty.
   std::vector<bool> available(labels->size(), true);
@@ -458,106 +621,20 @@ std::unique_ptr<EncodedProgram> AssemblyProgram::Encode() const {
   if (!encoded->ImportLabels(abs32_label_manager_, rel32_label_manager_))
     return nullptr;
 
-  for (size_t i = 0;  i < instructions_.size();  ++i) {
-    Instruction* instruction = instructions_[i];
+  auto it = instruction_raw_data_.begin();
+  auto end = instruction_raw_data_.end();
+  while (it < end) {
+    // Get the instruction from the operation.
+    AssemblyOp::OP op = static_cast<AssemblyOp::OP>(*it);
+    Instruction* instr = FindInstruction(op);
+    DCHECK_LE(it + instr->GetSize(), end);
 
-    switch (instruction->op()) {
-      case ORIGIN: {
-        OriginInstruction* org = static_cast<OriginInstruction*>(instruction);
-        if (!encoded->AddOrigin(org->origin_rva()))
-          return nullptr;
-        break;
-      }
-      case DEFBYTE: {
-        uint8_t b = static_cast<ByteInstruction*>(instruction)->byte_value();
-        if (!encoded->AddCopy(1, &b))
-          return nullptr;
-        break;
-      }
-      case DEFBYTES: {
-        const uint8_t* byte_values =
-            static_cast<BytesInstruction*>(instruction)->byte_values();
-        size_t len = static_cast<BytesInstruction*>(instruction)->len();
-
-        if (!encoded->AddCopy(len, byte_values))
-          return nullptr;
-        break;
-      }
-      case REL32: {
-        Label* label = static_cast<InstructionWithLabel*>(instruction)->label();
-        if (!encoded->AddRel32(label->index_))
-          return nullptr;
-        break;
-      }
-      case REL32ARM: {
-        Label* label =
-            static_cast<InstructionWithLabelARM*>(instruction)->label();
-        uint16_t compressed_op =
-            static_cast<InstructionWithLabelARM*>(instruction)->compressed_op();
-        if (!encoded->AddRel32ARM(compressed_op, label->index_))
-          return nullptr;
-        break;
-      }
-      case ABS32: {
-        Label* label = static_cast<InstructionWithLabel*>(instruction)->label();
-        if (!encoded->AddAbs32(label->index_))
-          return nullptr;
-        break;
-      }
-      case ABS64: {
-        Label* label = static_cast<InstructionWithLabel*>(instruction)->label();
-        if (!encoded->AddAbs64(label->index_))
-          return nullptr;
-        break;
-      }
-      case MAKEPERELOCS: {
-        if (!encoded->AddPeMakeRelocs(kind_))
-          return nullptr;
-        break;
-      }
-      case MAKEELFRELOCS: {
-        if (!encoded->AddElfMakeRelocs())
-          return nullptr;
-        break;
-      }
-      case MAKEELFARMRELOCS: {
-        if (!encoded->AddElfARMMakeRelocs())
-          return nullptr;
-        break;
-      }
-      default: {
-        NOTREACHED() << "Unknown Insn OP kind";
-      }
-    }
+    instr->Encode(it, encoded.get());
+    it += instr->GetSize();
   }
-
   return encoded;
 }
 
-Instruction* AssemblyProgram::GetByteInstruction(uint8_t byte) {
-  if (!byte_instruction_cache_) {
-    Instruction** ram = nullptr;
-    if (!base::UncheckedMalloc(sizeof(Instruction*) * 256,
-                               reinterpret_cast<void**>(&ram))) {
-      return nullptr;
-    }
-    byte_instruction_cache_.reset(ram);
-
-    for (int i = 0; i < 256; ++i) {
-      byte_instruction_cache_[i] =
-          UncheckedNew<ByteInstruction>(static_cast<uint8_t>(i));
-      if (!byte_instruction_cache_[i]) {
-        for (int j = 0; j < i; ++j)
-          UncheckedDelete(byte_instruction_cache_[j]);
-        byte_instruction_cache_.reset();
-        return nullptr;
-      }
-    }
-  }
-
-  return byte_instruction_cache_[byte];
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 
 Status Encode(const AssemblyProgram& program,