[interpreter] Introduce bytecode generation pipeline.

src/interpreter/bytecode-writer.h

Index: src/interpreter/bytecode-writer.h
diff --git a/src/interpreter/bytecode-writer.h b/src/interpreter/bytecode-writer.h
new file mode 100644
index 0000000000000000000000000000000000000000..bcbb76f522d4117d7098028d21b44b64251f2527
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+++ b/src/interpreter/bytecode-writer.h
@@ -0,0 +1,188 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_INTERPRETER_BYTECODE_WRITER_H_
+#define V8_INTERPRETER_BYTECODE_WRITER_H_
+
+#include "src/interpreter/bytecode-register-allocator.h"
+#include "src/interpreter/bytecodes.h"
+#include "src/zone-containers.h"
+
+namespace v8 {
+namespace internal {
+namespace interpreter {
+
+class BytecodeArrayBuilder;
+class SourcePositionTableBuilder;
+class TemporaryRegisterAllocator;
+
+class BytecodeNodeAllocator;
+
+// Source code position information.
+class BytecodeSourceInfo final {
+ public:
+  static const int kUninitializedPosition = -1;
+
+  BytecodeSourceInfo(int position = kUninitializedPosition,
+                     bool is_statement = false)
+      : source_position_(position), is_statement_(is_statement) {}
+
+  // Combine later source info with current.
+  void Update(const BytecodeSourceInfo& entry);
+
+  int source_position() const {
+    DCHECK(is_valid());
+    return source_position_;
+  }
+
+  int is_statement() const { return is_valid() && is_statement_; }
+
+  bool is_valid() const { return source_position_ != kUninitializedPosition; }
+  void set_invalid() { source_position_ = kUninitializedPosition; }
+
+  bool operator==(const BytecodeSourceInfo& other) const {
+    return source_position_ == other.source_position_ &&
+           is_statement_ == other.is_statement_;
+  }
+  bool operator!=(const BytecodeSourceInfo& other) const {
+    return source_position_ != other.source_position_ ||
+           is_statement_ != other.is_statement_;
+  }
+
+ private:
+  int source_position_;
+  bool is_statement_;
+
+  DISALLOW_COPY_AND_ASSIGN(BytecodeSourceInfo);
+};
+
+// A container for a generated bytecode, it's operands, and source information.
+// These must be allocated by a BytecodeNodeAllocator instance.
+class BytecodeNode final : ZoneObject {
+ public:
+  // Print to stream.
+  void Print(std::ostream& os);
+
+  // Return the size when this node is serialized to a bytecode array.
+  size_t Size() const;
+
+  // Return to node to allocator for re-use.
+  void Release();
+
+  Bytecode bytecode() const { return bytecode_; }
+  void set_bytecode(Bytecode bytecode);
+  void set_bytecode(Bytecode bytecode, uint32_t operand0,
+                    OperandScale operand_scale);
+  void set_bytecode(Bytecode bytecode, uint32_t operand0, uint32_t operand1,
+                    OperandScale operand_scale);
+  void set_bytecode(Bytecode bytecode, uint32_t operand0, uint32_t operand1,
+                    uint32_t operand2, OperandScale operand_scale);
+  void set_bytecode(Bytecode bytecode, uint32_t operand0, uint32_t operand1,
+                    uint32_t operand2, uint32_t operand3,
+                    OperandScale operand_scale);
+
+  uint32_t* operands() { return operands_; }
+  const uint32_t* operands() const { return operands_; }
+
+  int operand_count() const { return Bytecodes::NumberOfOperands(bytecode_); }
+
+  OperandScale operand_scale() const { return operand_scale_; }
+
+  const BytecodeSourceInfo& source_info() const { return source_info_; }
+  BytecodeSourceInfo& source_info() { return source_info_; }
+
+ private:
+  static const int kInvalidPosition = kMinInt;
+  static const size_t kMaxOperands = 4;
+
+  friend class BytecodeNodeAllocator;
+  explicit BytecodeNode(BytecodeNodeAllocator* allocator);
+
+  Bytecode bytecode_;
+  uint32_t operands_[kMaxOperands];
+  OperandScale operand_scale_;
+  BytecodeSourceInfo source_info_;
+  BytecodeNodeAllocator* allocator_;
+  BytecodeNode* next_;
+
+  DISALLOW_COPY_AND_ASSIGN(BytecodeNode);
+};
+
+// Allocator for BytecodeNodes that zone allocates them when needed
+// and maintains a freelist to reduce number of allocations and limit
+// memory use.
+class BytecodeNodeAllocator final {
+ public:
+  explicit BytecodeNodeAllocator(Zone* zone)
+      : allocation_count_(0), free_list_(nullptr), zone_(zone) {}
+
+  BytecodeNode* Allocate();
+
+ private:
+  friend class BytecodeNode;
+  static const int kMaxDebugAllocations = 8;
+
+  void Release(BytecodeNode* node);
+
+  Zone* zone() const { return zone_; }
+
+  int allocation_count_;
+  BytecodeNode* free_list_;
+  Zone* zone_;
+
+  DISALLOW_COPY_AND_ASSIGN(BytecodeNodeAllocator);
+};
+
+// Interface for bytecode writers.
+class BytecodeWriter {
+ public:
+  virtual ~BytecodeWriter() {}
+
+  // Flush state for bytecode array offset calculation. Returns the
+  // current size of bytecode array.
+  virtual size_t FlushForOffset() = 0;
+
+  // Signal end of basic block.
+  virtual void LeaveBasicBlock() = 0;
+
+  // Write bytecode into pipeline. The callee owns node from here and
+  // the caller should not hold any references to it.
+  virtual void Write(BytecodeNode* node) = 0;
+};
+
+// Class for emitting bytecode as the final stage of a bytecode writer
+// chain.
+class FinalStageBytecodeWriter : public BytecodeWriter {
+ public:
+  FinalStageBytecodeWriter(
+      Zone* zone, SourcePositionTableBuilder* source_position_table_builder);
+  virtual ~FinalStageBytecodeWriter();
+
+  size_t FlushForOffset() override;
+  void LeaveBasicBlock() override;
+  void Write(BytecodeNode* node) override;
+
+  // Get the bytecode vector.
+  ZoneVector<uint8_t>* bytecodes() { return &bytecodes_; }
+
+  // Returns the size in bytes of the frame associated with the
+  // bytecode written.
+  int GetMeasuredFrameSize();
+
+ private:
+  void EmitBytecode(const BytecodeNode* const node);
+  void UpdateSourcePositionTable(const BytecodeNode* const node);
+
+  ZoneVector<uint8_t> bytecodes_;
+  int frame_register_count_;
+  SourcePositionTableBuilder* source_position_table_builder_;
+
+  DISALLOW_COPY_AND_ASSIGN(FinalStageBytecodeWriter);
+};
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_INTERPRETER_BYTECODE_WRITER_H_