X87: Handle StepIn for constructors through PrepareStep just like for regular calls.

src/x87/builtins-x87.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_X87
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 128 matching lines @@
     __ push(ebx);
     __ SmiTag(eax);
     __ push(eax);
     __ push(edi);
     __ push(edx);
 
     // 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(masm->isolate());
-      __ cmp(Operand::StaticVariable(debug_step_in_fp), Immediate(0));
-      __ j(not_equal, &rt_call);
-
       // Verify that the new target is a JSFunction.
       __ CmpObjectType(edx, JS_FUNCTION_TYPE, ebx);
       __ j(not_equal, &rt_call);
 
       // Load the initial map and verify that it is in fact a map.
       // edx: new target
       __ mov(eax, FieldOperand(edx, JSFunction::kPrototypeOrInitialMapOffset));
       // Will both indicate a NULL and a Smi
       __ JumpIfSmi(eax, &rt_call);
       // edi: constructor
@@ skipping 258 matching lines @@
     // Copy arguments and receiver to the expression stack.
     Label loop, entry;
     __ mov(ecx, eax);
     __ jmp(&entry);
     __ bind(&loop);
     __ push(Operand(ebx, ecx, times_4, 0));
     __ bind(&entry);
     __ dec(ecx);
     __ j(greater_equal, &loop);
 
-    // Handle step in.
-    Label skip_step_in;
-    ExternalReference debug_step_in_fp =
-        ExternalReference::debug_step_in_fp_address(masm->isolate());
-    __ cmp(Operand::StaticVariable(debug_step_in_fp), Immediate(0));
-    __ j(equal, &skip_step_in);
-
-    __ push(eax);
-    __ push(edi);
-    __ push(edi);
-    __ CallRuntime(Runtime::kHandleStepInForDerivedConstructors, 1);
-    __ pop(edi);
-    __ pop(eax);
-
-    __ bind(&skip_step_in);
-
     // Invoke function.
     ParameterCount actual(eax);
     __ InvokeFunction(edi, actual, CALL_FUNCTION, NullCallWrapper());
 
     // Restore context from the frame.
     __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
 
     // Get arguments count, skipping over new.target.
     __ mov(ebx, Operand(esp, kPointerSize));
   }
@@ skipping 1468 matching lines @@
 
   __ bind(&ok);
   __ ret(0);
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87