[Interpreter] Add support for calling runtime functions which return a pair.

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 a04a93f1525cc023502dedd2c24d02696f50e5dc..bd93807a84d653e34ac2ce4614c8fc776e0e3948 100644
--- a/src/compiler/interpreter-assembler.cc
+++ b/src/compiler/interpreter-assembler.cc
@@ -148,6 +148,12 @@ Node* InterpreterAssembler::StoreRegister(Node* value, Node* reg_index) {
 }
 
 
+Node* InterpreterAssembler::NextRegister(Node* reg_index) {
+  // Register indexes are negative, so the next index is minus one.
+  return IntPtrAdd(reg_index, Int32Constant(-1));
+}
+
+
 Node* InterpreterAssembler::BytecodeOperand(int operand_index) {
   DCHECK_LT(operand_index, interpreter::Bytecodes::NumberOfOperands(bytecode_));
   DCHECK_EQ(interpreter::OperandSize::kByte,
@@ -554,13 +560,11 @@ Node* InterpreterAssembler::CallIC(CallInterfaceDescriptor descriptor,
 }
 
 
-Node* InterpreterAssembler::CallRuntime(Node* function_id, Node* first_arg,
+Node* InterpreterAssembler::CallRuntime(CallDescriptor* descriptor,
+                                        Handle<Code> call_stub,
+                                        Node* function_id, Node* first_arg,
                                         Node* arg_count) {
-  Callable callable = CodeFactory::InterpreterCEntry(isolate());
-  CallDescriptor* descriptor = Linkage::GetStubCallDescriptor(
-      isolate(), zone(), callable.descriptor(), 0, CallDescriptor::kNoFlags);
-
-  Node* code_target = HeapConstant(callable.code());
+  Node* code_target = HeapConstant(call_stub);
 
   // Get the function entry from the function id.
   Node* function_table = raw_assembler_->ExternalConstant(
@@ -582,6 +586,29 @@ Node* InterpreterAssembler::CallRuntime(Node* function_id, Node* first_arg,
 }
 
 
+Node* InterpreterAssembler::CallRuntime(Node* function_id, Node* first_arg,
+                                        Node* arg_count) {
+  Callable callable = CodeFactory::InterpreterCEntry(isolate());
+  CallDescriptor* descriptor = Linkage::GetStubCallDescriptor(
+      isolate(), zone(), callable.descriptor(), 0, CallDescriptor::kNoFlags);
+
+  return CallRuntime(descriptor, callable.code(), function_id, first_arg,
+                     arg_count);
+}
+
+
+Node* InterpreterAssembler::CallRuntimePair(Node* function_id, Node* first_arg,
+                                            Node* arg_count) {
+  Callable callable = CodeFactory::InterpreterCEntryPair(isolate());
+  CallDescriptor* descriptor = Linkage::GetStubCallDescriptor(
+      isolate(), zone(), callable.descriptor(), 0, CallDescriptor::kNoFlags,
+      Operator::kNoProperties, MachineType::AnyTagged(), 2);
+
+  return CallRuntime(descriptor, callable.code(), function_id, first_arg,
+                     arg_count);
+}
+
+
 Node* InterpreterAssembler::CallRuntime(Runtime::FunctionId function_id,
                                         Node* arg1) {
   CallPrologue();