Fix the previously ineffective assert checking the number of arguments passed to

runtime/vm/runtime_entry_x64.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/runtime_entry.h"
 
 #include "vm/assembler.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 #define __ assembler->
 
 
 // Generate code to call into the stub which will call the runtime
 // function. Input for the stub is as follows:
 //   RSP : points to the arguments and return value array.
 //   RBX : address of the runtime function to call.
 //   R10 : number of arguments to the call.
-void RuntimeEntry::Call(Assembler* assembler) const {
-  if (!is_leaf()) {
-    __ movq(RBX, Immediate(GetEntryPoint()));
-    __ movq(R10, Immediate(argument_count()));
-    __ call(&StubCode::CallToRuntimeLabel());
-  } else {
+void RuntimeEntry::Call(Assembler* assembler, intptr_t argument_count) const {
+  if (is_leaf()) {
+    ASSERT(argument_count == this->argument_count());
     ExternalLabel label(name(), GetEntryPoint());
     __ call(&label);
+  } else {
+    // Argument count is not checked here, but in the runtime entry for a more
+    // informative error message.
+    __ movq(RBX, Immediate(GetEntryPoint()));
+    __ movq(R10, Immediate(argument_count));
+    __ call(&StubCode::CallToRuntimeLabel());
   }
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64