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

src/interpreter/bytecode-array-builder.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_
 #define V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_
 
 #include <vector>
 
 #include "src/ast/ast.h"
@@ skipping 151 matching lines @@
   // applied to the constructor.
   BytecodeArrayBuilder& New(Register constructor, Register first_arg,
                             size_t arg_count);
 
   // Call the runtime function with |function_id|. The first argument should be
   // in |first_arg| and all subsequent arguments should be in registers
   // <first_arg + 1> to <first_arg + 1 + arg_count>.
   BytecodeArrayBuilder& CallRuntime(Runtime::FunctionId function_id,
                                     Register first_arg, size_t arg_count);
 
+  // Call the runtime function with |function_id| that returns a pair of values.
+  // The first argument should be in |first_arg| and all subsequent arguments
+  // should be in registers <first_arg + 1> to <first_arg + 1 + arg_count>. The
+  // return values will be returned in <first_return> and <first_return + 1>.
+  BytecodeArrayBuilder& CallRuntimePair(Runtime::FunctionId function_id,
+                                        Register first_arg, size_t arg_count,
+                                        Register first_return);
+
   // Call the JS runtime function with |context_index|. The the receiver should
   // be in |receiver| and all subsequent arguments should be in registers
   // <receiver + 1> to <receiver + 1 + arg_count>.
   BytecodeArrayBuilder& CallJSRuntime(int context_index, Register receiver,
                                       size_t arg_count);
 
   // Operators (register holds the lhs value, accumulator holds the rhs value).
   BytecodeArrayBuilder& BinaryOperation(Token::Value binop, Register reg,
                                         Strength strength);
 
@@ skipping 212 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(TemporaryRegisterScope);
 };
 
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_