[interpreter] Add field for handler table to bytecode array.

This adds a handler table field to the header of our BytecodeArray
objects. The field will eventually hold a range-based handler table
similar to full-codegen code, to support exception handlong within
interpreted code.

R=oth@chromium.org
BUG=v8:4674
LOG=n

Review URL: https://codereview.chromium.org/1606493002

Cr-Commit-Position: refs/heads/master@{#33373}

src/heap/heap.cc

@@ -3056,6 +3056,7 @@ AllocationResult Heap::AllocateBytecodeArray(int length,
   instance->set_frame_size(frame_size);
   instance->set_parameter_count(parameter_count);
   instance->set_constant_pool(constant_pool);
+  instance->set_handler_table(empty_fixed_array());
   CopyBytes(instance->GetFirstBytecodeAddress(), raw_bytecodes, length);
 
   return result;

src/objects-body-descriptors-inl.h

@@ -193,19 +193,21 @@ class JSArrayBuffer::BodyDescriptor final : public BodyDescriptorBase {
 class BytecodeArray::BodyDescriptor final : public BodyDescriptorBase {
  public:
   static bool IsValidSlot(HeapObject* obj, int offset) {
-    return offset == kConstantPoolOffset;
+    return offset == kConstantPoolOffset || offset == kHandlerTableOffset;
   }
 
   template <typename ObjectVisitor>
   static inline void IterateBody(HeapObject* obj, int object_size,
                                  ObjectVisitor* v) {
     IteratePointer(obj, kConstantPoolOffset, v);
+    IteratePointer(obj, kHandlerTableOffset, v);
   }
 
   template <typename StaticVisitor>
   static inline void IterateBody(HeapObject* obj, int object_size) {
     Heap* heap = obj->GetHeap();
     IteratePointer<StaticVisitor>(heap, obj, kConstantPoolOffset);
+    IteratePointer<StaticVisitor>(heap, obj, kHandlerTableOffset);
   }
 
   static inline int SizeOf(Map* map, HeapObject* obj) {

src/objects-inl.h

@@ -4050,6 +4050,7 @@ int BytecodeArray::parameter_count() const {
 
 
 ACCESSORS(BytecodeArray, constant_pool, FixedArray, kConstantPoolOffset)
+ACCESSORS(BytecodeArray, handler_table, FixedArray, kHandlerTableOffset)
 
 
 Address BytecodeArray::GetFirstBytecodeAddress() {

src/objects.h

@@ -4373,6 +4373,9 @@ class BytecodeArray : public FixedArrayBase {
   // Accessors for the constant pool.
   DECL_ACCESSORS(constant_pool, FixedArray)
 
+  // Accessors for handler table containing offsets of exception handlers.
+  DECL_ACCESSORS(handler_table, FixedArray)
+
   DECLARE_CAST(BytecodeArray)
 
   // Dispatched behavior.
@@ -4387,7 +4390,8 @@ class BytecodeArray : public FixedArrayBase {
   static const int kFrameSizeOffset = FixedArrayBase::kHeaderSize;
   static const int kParameterSizeOffset = kFrameSizeOffset + kIntSize;
   static const int kConstantPoolOffset = kParameterSizeOffset + kIntSize;
-  static const int kHeaderSize = kConstantPoolOffset + kPointerSize;
+  static const int kHandlerTableOffset = kConstantPoolOffset + kPointerSize;
+  static const int kHeaderSize = kHandlerTableOffset + kPointerSize;
 
   static const int kAlignedSize = OBJECT_POINTER_ALIGN(kHeaderSize);