Handle StepIn for constructors through PrepareStep just like for regular calls

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.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/arm64/frames-arm64.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
@@ skipping 353 matching lines @@
     __ Push(allocation_site, argc, constructor, new_target);
     // sp[0]: new.target
     // sp[1]: Constructor function.
     // sp[2]: number of arguments (smi-tagged)
     // sp[3]: allocation site
 
     // Try to allocate the object without transitioning into C code. If any of
     // the preconditions is not met, the code bails out to the runtime call.
     Label rt_call, allocated;
     if (FLAG_inline_new) {
-      ExternalReference debug_step_in_fp =
-          ExternalReference::debug_step_in_fp_address(isolate);
-      __ Mov(x2, Operand(debug_step_in_fp));
-      __ Ldr(x2, MemOperand(x2));
-      __ Cbnz(x2, &rt_call);
-
       // Verify that the new target is a JSFunction.
       __ JumpIfNotObjectType(new_target, x10, x11, JS_FUNCTION_TYPE, &rt_call);
 
       // Load the initial map and verify that it is in fact a map.
       Register init_map = x2;
       __ Ldr(init_map,
              FieldMemOperand(new_target,
                              JSFunction::kPrototypeOrInitialMapOffset));
       __ JumpIfSmi(init_map, &rt_call);
       __ JumpIfNotObjectType(init_map, x10, x11, MAP_TYPE, &rt_call);
@@ skipping 300 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);
 
-    // 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
     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));
@@ skipping 1294 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM