Handle StepIn for constructors through PrepareStep just like for regular calls

src/arm/builtins-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.
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 348 matching lines @@
     __ push(r2);
     __ SmiTag(r0);
     __ push(r0);
     __ push(r1);
     __ push(r3);
 
     // 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(r2, Operand(debug_step_in_fp));
-      __ ldr(r2, MemOperand(r2));
-      __ tst(r2, r2);
-      __ b(ne, &rt_call);
-
       // Verify that the new target is a JSFunction.
       __ CompareObjectType(r3, r5, r4, JS_FUNCTION_TYPE);
       __ b(ne, &rt_call);
 
       // Load the initial map and verify that it is in fact a map.
       // r3: new target
       __ ldr(r2, FieldMemOperand(r3, JSFunction::kPrototypeOrInitialMapOffset));
       __ JumpIfSmi(r2, &rt_call);
       __ CompareObjectType(r2, r5, r4, MAP_TYPE);
       __ b(ne, &rt_call);
@@ skipping 284 matching lines @@
     // sp[2]: number of arguments (smi-tagged)
     Label loop, entry;
     __ b(&entry);
     __ bind(&loop);
     __ ldr(ip, MemOperand(r2, r4, LSL, kPointerSizeLog2 - 1));
     __ push(ip);
     __ bind(&entry);
     __ sub(r4, r4, Operand(2), SetCC);
     __ b(ge, &loop);
 
-    // Handle step in.
-    Label skip_step_in;
-    ExternalReference debug_step_in_fp =
-        ExternalReference::debug_step_in_fp_address(masm->isolate());
-    __ mov(r2, Operand(debug_step_in_fp));
-    __ ldr(r2, MemOperand(r2));
-    __ tst(r2, r2);
-    __ b(eq, &skip_step_in);
-
-    __ Push(r0);
-    __ Push(r1);
-    __ Push(r1);
-    __ CallRuntime(Runtime::kHandleStepInForDerivedConstructors, 1);
-    __ Pop(r1);
-    __ Pop(r0);
-
-    __ bind(&skip_step_in);
-
     // Call the function.
     // r0: number of arguments
     // r1: constructor function
     ParameterCount actual(r0);
     __ InvokeFunction(r1, actual, CALL_FUNCTION, NullCallWrapper());
 
     // Restore context from the frame.
     // r0: result
     // sp[0]: number of arguments (smi-tagged)
     __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
@@ skipping 1219 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM