[debugger] simplify debug stepping.

src/ia32/builtins-ia32.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_IA32
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 391 matching lines @@
   // Store resume mode into generator object.
   __ mov(FieldOperand(ebx, JSGeneratorObject::kResumeModeOffset), edx);
 
   // Load suspended function and context.
   __ mov(esi, FieldOperand(ebx, JSGeneratorObject::kContextOffset));
   __ mov(edi, FieldOperand(ebx, JSGeneratorObject::kFunctionOffset));
 
   // Flood function if we are stepping.
   Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
   Label stepping_prepared;
-  ExternalReference step_in_enabled =
-      ExternalReference::debug_step_in_enabled_address(masm->isolate());
-  __ cmpb(Operand::StaticVariable(step_in_enabled), Immediate(0));
-  __ j(not_equal, &prepare_step_in_if_stepping);
+  ExternalReference last_step_action =
+      ExternalReference::debug_last_step_action_address(masm->isolate());
+  STATIC_ASSERT(StepFrame > StepIn);
+  __ cmpb(Operand::StaticVariable(last_step_action), Immediate(StepIn));
+  __ j(greater_equal, &prepare_step_in_if_stepping);
 
   // Flood function if we need to continue stepping in the suspended generator.
   ExternalReference debug_suspended_generator =
       ExternalReference::debug_suspended_generator_address(masm->isolate());
   __ cmp(ebx, Operand::StaticVariable(debug_suspended_generator));
   __ j(equal, &prepare_step_in_suspended_generator);
   __ bind(&stepping_prepared);
 
   // Pop return address.
   __ PopReturnAddressTo(eax);
@@ skipping 2536 matching lines @@
   // And "return" to the OSR entry point of the function.
   __ ret(0);
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32