[Interpreter] Add support for loading literals from the constant pool.

src/compiler/interpreter-assembler.cc

Index: src/compiler/interpreter-assembler.cc
diff --git a/src/compiler/interpreter-assembler.cc b/src/compiler/interpreter-assembler.cc
index d6ca45fc54f5a0e9cc7538fdc6644c9da9308fc1..25d1b5eacffe1ef208e2553eef4246e1da0df9f6 100644
--- a/src/compiler/interpreter-assembler.cc
+++ b/src/compiler/interpreter-assembler.cc
@@ -147,6 +147,13 @@ Node* InterpreterAssembler::BytecodeOperandImm8(int operand_index) {
 }
 
 
+Node* InterpreterAssembler::BytecodeOperandIdx(int operand_index) {
+  DCHECK_EQ(interpreter::OperandType::kIdx,
+            interpreter::Bytecodes::GetOperandType(bytecode_, operand_index));
+  return BytecodeOperand(operand_index);
+}
+
+
 Node* InterpreterAssembler::BytecodeOperandReg(int operand_index) {
   DCHECK_EQ(interpreter::OperandType::kReg,
             interpreter::Bytecodes::GetOperandType(bytecode_, operand_index));
@@ -189,6 +196,16 @@ Node* InterpreterAssembler::SmiUntag(Node* value) {
 }
 
 
+Node* InterpreterAssembler::LoadConstantPoolEntry(Node* index) {
+  Node* constant_pool = LoadObjectField(BytecodeArrayTaggedPointer(),
+                                        BytecodeArray::kConstantPoolOffset);
+  Node* entry_offset = raw_assembler_->IntPtrAdd(
+      IntPtrConstant(FixedArray::kHeaderSize - kHeapObjectTag),
+      raw_assembler_->WordShl(index, Int32Constant(kPointerSizeLog2)));
+  return raw_assembler_->Load(kMachAnyTagged, constant_pool, entry_offset);
+}
+
+
 Node* InterpreterAssembler::LoadObjectField(Node* object, int offset) {
   return raw_assembler_->Load(kMachAnyTagged, object,
                               IntPtrConstant(offset - kHeapObjectTag));