[debugger] flood function for stepping before calling it.

src/x64/builtins-x64.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_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 314 matching lines @@
     __ j(greater_equal, &loop);
 
     // Call the function.
     if (is_api_function) {
       __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
       Handle<Code> code =
           masm->isolate()->builtins()->HandleApiCallConstruct();
       __ Call(code, RelocInfo::CODE_TARGET);
     } else {
       ParameterCount actual(rax);
-      __ InvokeFunction(rdi, rdx, actual, CALL_FUNCTION, NullCallWrapper());
+      __ InvokeFunction(rdi, rdx, actual, CALL_FUNCTION,
+                        CheckDebugStepCallWrapper());
     }
 
     // Store offset of return address for deoptimizer.
     if (create_implicit_receiver && !is_api_function) {
       masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
     }
 
     // Restore context from the frame.
     __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 
@@ skipping 1382 matching lines @@
 
   // ----------- S t a t e -------------
   //  -- rax : the number of arguments (not including the receiver)
   //  -- rdx : the shared function info.
   //  -- rdi : the function to call (checked to be a JSFunction)
   //  -- rsi : the function context.
   // -----------------------------------
 
   __ LoadSharedFunctionInfoSpecialField(
       rbx, rdx, SharedFunctionInfo::kFormalParameterCountOffset);
-  __ movp(r8, FieldOperand(rdi, JSFunction::kCodeEntryOffset));
   ParameterCount actual(rax);
   ParameterCount expected(rbx);
-  __ InvokeCode(r8, no_reg, expected, actual, JUMP_FUNCTION, NullCallWrapper());
+
+  __ InvokeFunctionCode(rdi, no_reg, expected, actual, JUMP_FUNCTION,
+                        CheckDebugStepCallWrapper());
 
   // The function is a "classConstructor", need to raise an exception.
   __ bind(&class_constructor);
   {
     FrameScope frame(masm, StackFrame::INTERNAL);
     __ Push(rdi);
     __ CallRuntime(Runtime::kThrowConstructorNonCallableError, 1);
   }
 }
 
@@ skipping 309 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64