Check for a passed-in type argument vector in the prolog of generic functions.

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2013, 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/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 815 matching lines @@
 #endif
 
   __ movq(Address(THR, Thread::top_exit_frame_info_offset()), Immediate(0));
 
   // Load arguments descriptor array into R10, which is passed to Dart code.
   __ movq(R10, Address(kArgDescReg, VMHandles::kOffsetOfRawPtrInHandle));
 
   // Push arguments. At this point we only need to preserve kTargetCodeReg.
   ASSERT(kTargetCodeReg != RDX);
 
+  // TODO(regis): Do we need to support type arguments when calling from C++?

[rmacnak, 2017/06/14 00:14:20]

Or mirrors? *cringe*

Let's not add this until there's a specific request for it.

[regis, 2017/06/14 21:02:05]

Agreed.

+  // TODO(regis): Add this check or proper implementation to other platforms.
+  __ cmpq(FieldAddress(R10, ArgumentsDescriptor::type_args_len_offset()),
+          Immediate(0));
+  Label no_type_args;
+  __ j(EQUAL, &no_type_args, Assembler::kNearJump);
+  __ int3();
+  __ Bind(&no_type_args);
+
   // 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(kArgsReg, VMHandles::kOffsetOfRawPtrInHandle));
   __ leaq(RDX, FieldAddress(RDX, Array::data_offset()));
 
   // Set up arguments for the Dart call.
   Label push_arguments;
@@ skipping 1473 matching lines @@
 }
 
 
 void StubCode::GenerateAsynchronousGapMarkerStub(Assembler* assembler) {
   __ int3();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64