[interpreter] Add support for scalable operands.

src/interpreter/interpreter.h

Index: src/interpreter/interpreter.h
diff --git a/src/interpreter/interpreter.h b/src/interpreter/interpreter.h
index 647f95849d004dbc9e17dde14707e5f4b8f35a0e..075fe741e943f064f22184c727cc04c823ea3fb3 100644
--- a/src/interpreter/interpreter.h
+++ b/src/interpreter/interpreter.h
@@ -40,7 +40,7 @@ class Interpreter {
   static bool MakeBytecode(CompilationInfo* info);
 
   // Return bytecode handler for |bytecode|.
-  Code* GetBytecodeHandler(Bytecode bytecode);
+  Code* GetBytecodeHandler(Bytecode bytecode, OperandScale operand_scale);
 
   // GC support.
   void IterateDispatchTable(ObjectVisitor* v);
@@ -53,6 +53,10 @@ class Interpreter {
     return reinterpret_cast<Address>(&dispatch_table_[0]);
   }
 
+  // Returns true if a handler is generated for a bytecode at a given
+  // operand scale.
+  static bool BytecodeHasHandler(Bytecode bytecode, OperandScale operand_scale);
+
  private:
 // Bytecode handler generator functions.
 #define DECLARE_BYTECODE_HANDLER_GENERATOR(Name, ...) \
@@ -130,9 +134,14 @@ class Interpreter {
   void DoStoreLookupSlot(LanguageMode language_mode,
                          InterpreterAssembler* assembler);
 
+  // Get dispatch table index of bytecode.
+  static size_t GetDispatchTableIndex(Bytecode bytecode,
+                                      OperandScale operand_scale);
+
   bool IsDispatchTableInitialized();
 
-  static const int kDispatchTableSize = static_cast<int>(Bytecode::kLast) + 1;
+  static const int kNumberOfWideVariants = 3;
+  static const int kDispatchTableSize = kNumberOfWideVariants * (kMaxUInt8 + 1);
 
   Isolate* isolate_;
   Code* dispatch_table_[kDispatchTableSize];