PPC: [debugger] simplify debug stepping.

src/ppc/macro-assembler-ppc.cc

 // Copyright 2014 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.
 
 #include <assert.h>  // For assert
 #include <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_PPC
 
 #include "src/base/bits.h"
@@ skipping 1368 matching lines @@
     }
     bind(&regular_invoke);
   }
 }
 
 
 void MacroAssembler::FloodFunctionIfStepping(Register fun, Register new_target,
                                              const ParameterCount& expected,
                                              const ParameterCount& actual) {
   Label skip_flooding;
-  ExternalReference step_in_enabled =
-      ExternalReference::debug_step_in_enabled_address(isolate());
-  mov(r7, Operand(step_in_enabled));
-  lbz(r7, MemOperand(r7));
-  cmpi(r7, Operand::Zero());
-  beq(&skip_flooding);
+  ExternalReference last_step_action =
+      ExternalReference::debug_last_step_action_address(isolate());
+  STATIC_ASSERT(StepFrame > StepIn);
+  mov(r7, Operand(last_step_action));
+  LoadByte(r7, MemOperand(r7), r0);
+  extsb(r7, r7);
+  cmpi(r7, Operand(StepIn));
+  blt(&skip_flooding);
   {
     FrameScope frame(this,
                      has_frame() ? StackFrame::NONE : StackFrame::INTERNAL);
     if (expected.is_reg()) {
       SmiTag(expected.reg());
       Push(expected.reg());
     }
     if (actual.is_reg()) {
       SmiTag(actual.reg());
       Push(actual.reg());
@@ skipping 3481 matching lines @@
   }
   if (mag.shift > 0) srawi(result, result, mag.shift);
   ExtractBit(r0, dividend, 31);
   add(result, result, r0);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC