[Interpreter] Add BytecodeArray class and add to SharedFunctionInfo.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 16938972ba28f1a2af618a731cb2314502adf6d2..beb21e95508d276b62f3b6404ce7268d45a805cf 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -73,6 +73,7 @@
 //         - JSFunctionProxy
 //     - FixedArrayBase
 //       - ByteArray
+//         - BytecodeArray
 //       - FixedArray
 //         - DescriptorArray
 //         - HashTable
@@ -398,6 +399,7 @@ const int kStubMinorKeyBits = kSmiValueSize - kStubMajorKeyBits - 1;
   V(FLOAT32X4_TYPE)                                             \
   V(FOREIGN_TYPE)                                               \
   V(BYTE_ARRAY_TYPE)                                            \
+  V(BYTECODE_ARRAY_TYPE)                                        \
   V(FREE_SPACE_TYPE)                                            \
   /* Note: the order of these external array */                 \
   /* types is relied upon in */                                 \
@@ -694,6 +696,7 @@ enum InstanceType {
   FLOAT32X4_TYPE,  // FIRST_SIMD_TYPE, LAST_SIMD_TYPE
   FOREIGN_TYPE,
   BYTE_ARRAY_TYPE,
+  BYTECODE_ARRAY_TYPE,
   FREE_SPACE_TYPE,
   EXTERNAL_INT8_ARRAY_TYPE,  // FIRST_EXTERNAL_ARRAY_TYPE
   EXTERNAL_UINT8_ARRAY_TYPE,
@@ -960,6 +963,7 @@ template <class C> inline bool Is(Object* obj);
   V(FixedUint8ClampedArray)        \
   V(Float32x4)                     \
   V(ByteArray)                     \
+  V(BytecodeArray)                 \
   V(FreeSpace)                     \
   V(JSReceiver)                    \
   V(JSObject)                      \
@@ -4260,6 +4264,49 @@ class ByteArray: public FixedArrayBase {
 };
 
 
+// BytecodeArray represents a sequence of interpreter bytecodes.
+class BytecodeArray : public ByteArray {
+ public:
+  static int SizeFor(int length) {
+    return OBJECT_POINTER_ALIGN(kHeaderSize + length);
+  }
+
+  // Returns data start address.
+  inline Address GetFirstBytecodeAddress();
+
+  // Accessors for frame size and the number of locals
+  inline int frame_size() const;
+  inline void set_frame_size(int value);
+  inline int number_of_locals() const;
+  inline void set_number_of_locals(int value);
+
+  DECLARE_CAST(BytecodeArray)
+
+  // Dispatched behavior.
+  inline int BytecodeArraySize() { return SizeFor(this->length()); }
+
+  DECLARE_PRINTER(BytecodeArray)
+  DECLARE_VERIFIER(BytecodeArray)
+
+  void Disassemble(std::ostream& os);
+
+  // Layout description.
+  static const int kFrameSizeOffset = ByteArray::kHeaderSize;
+  static const int kNumberOfLocalsOffset = kFrameSizeOffset + kIntSize;
+  static const int kHeaderSize = kNumberOfLocalsOffset + kIntSize;
+
+  static const int kAlignedSize = OBJECT_POINTER_ALIGN(kHeaderSize);
+
+  // Maximal memory consumption for a single BytecodeArray.
+  static const int kMaxSize = ByteArray::kMaxSize;
+  // Maximal length of a single BytecodeArray.
+  static const int kMaxLength = kMaxSize - kHeaderSize;
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(BytecodeArray);
+};
+
+
 // FreeSpace are fixed-size free memory blocks used by the heap and GC.
 // They look like heap objects (are heap object tagged and have a map) so that
 // the heap remains iterable.  They have a size and a next pointer.
@@ -6659,6 +6706,9 @@ class SharedFunctionInfo: public HeapObject {
   // Clear the type feedback vector with a more subtle policy at GC time.
   void ClearTypeFeedbackInfoAtGCTime();
 
+  // [bytecode_array]: Interpreter bytecodes.
+  DECL_ACCESSORS(bytecode_array, BytecodeArray)

[ulan, 2015/07/21 11:55:24]

This will increase memory footprint. Couple of month ago I saw that google inbox
had ~50K shared function infos. So this would mean additional 200K-400K live
memory depending on architecture.

Maybe we can find a way to stash the pointer somewhere, so that we pay the cost
only when there is an actual byte array? Or do this behind build flag.

[oth, 2015/07/21 20:39:26]

Done. Moved to SharedFunctionInfo::function_data.

+
 #if TRACE_MAPS
   // [unique_id] - For --trace-maps purposes, an identifier that's persistent
   // even if the GC moves this SharedFunctionInfo.
@@ -6932,13 +6982,14 @@ class SharedFunctionInfo: public HeapObject {
   static const int kInferredNameOffset = kDebugInfoOffset + kPointerSize;
   static const int kFeedbackVectorOffset =
       kInferredNameOffset + kPointerSize;
+  static const int kBytecodeArrayOffset = kFeedbackVectorOffset + kPointerSize;
 #if TRACE_MAPS
-  static const int kUniqueIdOffset = kFeedbackVectorOffset + kPointerSize;
+  static const int kUniqueIdOffset = kBytecodeArrayOffset + kPointerSize;
   static const int kLastPointerFieldOffset = kUniqueIdOffset;
 #else
   // Just to not break the postmortrem support with conditional offsets
-  static const int kUniqueIdOffset = kFeedbackVectorOffset;
-  static const int kLastPointerFieldOffset = kFeedbackVectorOffset;
+  static const int kUniqueIdOffset = kBytecodeArrayOffset;
+  static const int kLastPointerFieldOffset = kBytecodeArrayOffset;
 #endif
 
 #if V8_HOST_ARCH_32_BIT