WIP [esnext] implement async iteration proposal

src/arm/macro-assembler-arm.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.
 
 #include <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 2977 matching lines @@
     Check(ne, kOperandIsASmiAndNotABoundFunction);
     push(object);
     CompareObjectType(object, object, object, JS_BOUND_FUNCTION_TYPE);
     pop(object);
     Check(eq, kOperandIsNotABoundFunction);
   }
 }
 
 void MacroAssembler::AssertGeneratorObject(Register object) {
   if (emit_debug_code()) {
+    Label ok;
     STATIC_ASSERT(kSmiTag == 0);
     tst(object, Operand(kSmiTagMask));
     Check(ne, kOperandIsASmiAndNotAGeneratorObject);
     push(object);
     CompareObjectType(object, object, object, JS_GENERATOR_OBJECT_TYPE);
     pop(object);
+    b(eq, &ok);
+
+    push(object);
+    CompareObjectType(object, object, object, JS_ASYNC_GENERATOR_OBJECT_TYPE);
+    pop(object);
     Check(eq, kOperandIsNotAGeneratorObject);
+
+    bind(&ok);
   }
 }
 
 void MacroAssembler::AssertReceiver(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
     tst(object, Operand(kSmiTagMask));
     Check(ne, kOperandIsASmiAndNotAReceiver);
     push(object);
     STATIC_ASSERT(LAST_TYPE == LAST_JS_RECEIVER_TYPE);
@@ skipping 857 matching lines @@
     }
   }
   if (mag.shift > 0) mov(result, Operand(result, ASR, mag.shift));
   add(result, result, Operand(dividend, LSR, 31));
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM