Changed the API in DartEntry for invoking dart code from C++ to make it more compatible with the re…

vm/stub_code_x64.cc

 // Copyright (c) 2012, 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/assembler.h"
 #include "vm/assembler_macros.h"
 #include "vm/compiler.h"
@@ skipping 685 matching lines @@
   __ LeaveFrame();
   __ ret();
 }
 
 
 // Called when invoking Dart code from C++ (VM code).
 // Input parameters:
 //   RSP : points to return address.
 //   RDI : entrypoint of the Dart function to call.
 //   RSI : arguments descriptor array.
-//   RDX : pointer to the argument array.
+//   RDX : arguments array.
 //   RCX : new context containing the current isolate pointer.
 void StubCode::GenerateInvokeDartCodeStub(Assembler* assembler) {
   // Save frame pointer coming in.
   __ EnterFrame(0);
 
   // Save arguments descriptor array and new context.
   const intptr_t kArgumentsDescOffset = -1 * kWordSize;
   __ pushq(RSI);
   const intptr_t kNewContextOffset = -2 * kWordSize;
   __ pushq(RCX);
@@ skipping 33 matching lines @@
   __ movq(RAX, Address(R8, Isolate::top_context_offset()));
   __ pushq(RAX);
 
   // Load arguments descriptor array into R10, which is passed to Dart code.
   __ movq(R10, Address(RSI, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Load number of arguments into RBX.
   __ movq(RBX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
   __ SmiUntag(RBX);
 
+  // Compute address of 'arguments array' data area into RDX.
+  __ movq(RDX, Address(RDX, VMHandles::kOffsetOfRawPtrInHandle));
+  __ leaq(RDX, FieldAddress(RDX, Array::data_offset()));
+
   // Set up arguments for the Dart call.
   Label push_arguments;
   Label done_push_arguments;
   __ testq(RBX, RBX);  // check if there are arguments.
   __ j(ZERO, &done_push_arguments, Assembler::kNearJump);
   __ movq(RAX, Immediate(0));
   __ Bind(&push_arguments);
   __ movq(RCX, Address(RDX, RAX, TIMES_8, 0));  // RDX is start of arguments.
-  __ movq(RCX, Address(RCX, VMHandles::kOffsetOfRawPtrInHandle));
   __ pushq(RCX);
   __ incq(RAX);
   __ cmpq(RAX, RBX);
   __ j(LESS, &push_arguments, Assembler::kNearJump);
   __ Bind(&done_push_arguments);
 
   // Call the Dart code entrypoint.
   __ call(RDI);  // R10 is the arguments descriptor array.
 
   // Read the saved new Context pointer.
@@ skipping 1287 matching lines @@
   __ cmpq(left, right);
   __ Bind(&done);
   __ popq(right);
   __ popq(left);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64