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

test/unittests/compiler/interpreter-assembler-unittest.cc

Index: test/unittests/compiler/interpreter-assembler-unittest.cc
diff --git a/test/unittests/compiler/interpreter-assembler-unittest.cc b/test/unittests/compiler/interpreter-assembler-unittest.cc
index 1e49b08e80d46b07c67aee6d2d3a861b41beb09f..339b61b5b9832aeb5f0fb27805aefc8f0f6cff56 100644
--- a/test/unittests/compiler/interpreter-assembler-unittest.cc
+++ b/test/unittests/compiler/interpreter-assembler-unittest.cc
@@ -619,6 +619,34 @@ TARGET_TEST_F(InterpreterAssemblerTest, CallRuntime) {
 }
 
 
+TARGET_TEST_F(InterpreterAssemblerTest, CallRuntimePair) {
+  TRACED_FOREACH(interpreter::Bytecode, bytecode, kBytecodes) {
+    InterpreterAssemblerForTest m(this, bytecode);
+    Callable builtin = CodeFactory::InterpreterCEntryPair(isolate());
+
+    Node* function_id = m.Int32Constant(0);
+    Node* first_arg = m.Int32Constant(1);
+    Node* arg_count = m.Int32Constant(2);
+
+    Matcher<Node*> function_table = IsExternalConstant(
+        ExternalReference::runtime_function_table_address(isolate()));
+    Matcher<Node*> function = IsIntPtrAdd(
+        function_table,
+        IsInt32Mul(function_id, IsInt32Constant(sizeof(Runtime::Function))));
+    Matcher<Node*> function_entry =
+        m.IsLoad(MachineType::Pointer(), function,
+                 IsInt32Constant(offsetof(Runtime::Function, entry)));
+
+    Node* call_runtime = m.CallRuntime(function_id, first_arg, arg_count);
+    EXPECT_THAT(
+        call_runtime,
+        IsCall(_, IsHeapConstant(builtin.code()), arg_count, first_arg,
+               function_entry,
+               IsParameter(Linkage::kInterpreterContextParameter), _, _));
+  }
+}
+
+
 TARGET_TEST_F(InterpreterAssemblerTest, CallIC) {
   TRACED_FOREACH(interpreter::Bytecode, bytecode, kBytecodes) {
     InterpreterAssemblerForTest m(this, bytecode);