[interpreter] move the dispatch table off heap.

src/ppc/builtins-ppc.cc

Index: src/ppc/builtins-ppc.cc
diff --git a/src/ppc/builtins-ppc.cc b/src/ppc/builtins-ppc.cc
index 912971c5d0a06025282313f57137c4336067a88f..f8e04175523f5ccc50a072d47808d3ae14d6cb9f 100644
--- a/src/ppc/builtins-ppc.cc
+++ b/src/ppc/builtins-ppc.cc
@@ -1039,10 +1039,9 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
           Operand(InterpreterFrameConstants::kRegisterFilePointerFromFp));
   __ mov(kInterpreterBytecodeOffsetRegister,
          Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
-  __ LoadRoot(kInterpreterDispatchTableRegister,
-              Heap::kInterpreterTableRootIndex);
-  __ addi(kInterpreterDispatchTableRegister, kInterpreterDispatchTableRegister,
-          Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+  __ mov(kInterpreterDispatchTableRegister,
+         Operand(ExternalReference::interpreter_dispatch_table_address(
+             masm->isolate())));
 
   // Dispatch to the first bytecode handler for the function.
   __ lbzx(r4, MemOperand(kInterpreterBytecodeArrayRegister,
@@ -1141,10 +1140,9 @@ static void Generate_EnterBytecodeDispatch(MacroAssembler* masm) {
   // Initialize register file register and dispatch table register.
   __ addi(kInterpreterRegisterFileRegister, fp,
           Operand(InterpreterFrameConstants::kRegisterFilePointerFromFp));
-  __ LoadRoot(kInterpreterDispatchTableRegister,
-              Heap::kInterpreterTableRootIndex);
-  __ addi(kInterpreterDispatchTableRegister, kInterpreterDispatchTableRegister,
-          Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+  __ mov(kInterpreterDispatchTableRegister,
+         Operand(ExternalReference::interpreter_dispatch_table_address(
+             masm->isolate())));
 
   // Get the context from the frame.
   __ LoadP(kContextRegister,