[Interpreter] Add support for parameter variables.

src/x64/builtins-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 784 matching lines @@
   // TODO(rmcilroy): List of things not currently dealt with here but done in
   // fullcodegen's EmitReturnSequence.
   //  - Supporting FLAG_trace for Runtime::TraceExit.
   //  - Support profiler (specifically decrementing profiling_counter
   //    appropriately and calling out to HandleInterrupts if necessary).
 
   // The return value is in accumulator, which is already in rax.
 
   // Leave the frame (also dropping the register file).
   __ leave();
-  // Return droping receiver + arguments.
-  // TODO(rmcilroy): Get number of arguments from BytecodeArray.
-  __ Ret(1 * kPointerSize, rcx);
+
+  // Drop receiver + arguments and return.
+  __ movl(rbx, FieldOperand(kInterpreterBytecodeArrayRegister,
+                            BytecodeArray::kParameterSizeOffset));
+  __ PopReturnAddressTo(rcx);
+  __ addp(rsp, rbx);
+  __ PushReturnAddressFrom(rcx);
+  __ ret(0);
 }
 
 
 void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   CallRuntimePassFunction(masm, Runtime::kCompileLazy);
   GenerateTailCallToReturnedCode(masm);
 }
 
 
 static void CallCompileOptimized(MacroAssembler* masm,
@@ skipping 1032 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64