new classes: no longer experimental.

src/arm64/builtins-arm64.cc

 // Copyright 2013 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 "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/codegen.h"
 #include "src/debug.h"
@@ skipping 740 matching lines @@
     __ Push(x11, x10);
     __ Bind(&entry);
     __ Cmp(x4, x2);
     __ B(gt, &loop);
     // Because we copied values 2 by 2 we may have copied one extra value.
     // Drop it if that is the case.
     __ B(eq, &done_copying_arguments);
     __ Drop(1);
     __ Bind(&done_copying_arguments);
 
+    __ Add(x0, x0, Operand(1));  // new.target
+
+    // Handle step in.
+    Label skip_step_in;
+    ExternalReference debug_step_in_fp =
+        ExternalReference::debug_step_in_fp_address(masm->isolate());
+    __ Mov(x2, Operand(debug_step_in_fp));
+    __ Ldr(x2, MemOperand(x2));
+    __ Cbz(x2, &skip_step_in);
+
+    __ Push(x0, x1, x1);
+    __ CallRuntime(Runtime::kHandleStepInForDerivedConstructors, 1);
+    __ Pop(x1, x0);
+
+    __ bind(&skip_step_in);
+
     // Call the function.
     // x0: number of arguments
     // x1: constructor function
-    __ Add(x0, x0, Operand(1));  // new.target
     ParameterCount actual(x0);
     __ InvokeFunction(x1, actual, CALL_FUNCTION, NullCallWrapper());
 
 
     // Restore the context from the frame.
     // x0: result
     // jssp[0]: number of arguments (smi-tagged)
     __ Ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
 
     // Load number of arguments (smi).
@@ skipping 878 matching lines @@
     __ Unreachable();
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM