Debugger: do not compile IC for accessors when debugging.

The invariant is that as long as there is a debug info on
the shared function info, no accessor IC is compiled for
its code. That way we can guarantee that stepping into
accessors, which requires a debug info, works for accessors.

Review URL: https://codereview.chromium.org/1220283009

Cr-Commit-Position: refs/heads/master@{#29546}

src/debug.cc

@@ -1351,7 +1351,7 @@ void Debug::PrepareStep(StepAction step_action,
       }
     }
 
-    ActivateStepIn(function, frame);
+    ActivateStepIn(frame);
   }
 
   // Fill the current function with one-shot break points even for step in on
@@ -1509,12 +1509,8 @@ void Debug::ClearOneShot() {
 }
 
 
-void Debug::ActivateStepIn(Handle<JSFunction> function, StackFrame* frame) {
+void Debug::ActivateStepIn(StackFrame* frame) {
   DCHECK(!StepOutActive());
-  // Make sure IC state is clean. This is so that we correct flood
-  // accessor pairs when stepping in.
-  function->code()->ClearInlineCaches();
-  function->shared()->feedback_vector()->ClearICSlots(function->shared());
   thread_local_.step_into_fp_ = frame->UnpaddedFP();
 }
 
@@ -2070,6 +2066,11 @@ bool Debug::EnsureDebugInfo(Handle<SharedFunctionInfo> shared,
     return false;
   }
 
+  // Make sure IC state is clean. This is so that we correctly flood
+  // accessor pairs when stepping in.
+  shared->code()->ClearInlineCaches();
+  shared->feedback_vector()->ClearICSlots(*shared);
+
   // Create the debug info object.
   Handle<DebugInfo> debug_info = isolate->factory()->NewDebugInfo(shared);
 

src/debug.h

@@ -624,7 +624,7 @@ class Debug {
 
   static bool CompileDebuggerScript(Isolate* isolate, int index);
   void ClearOneShot();
-  void ActivateStepIn(Handle<JSFunction> function, StackFrame* frame);
+  void ActivateStepIn(StackFrame* frame);
   void ClearStepIn();
   void ActivateStepOut(StackFrame* frame);
   void ClearStepNext();

src/ic/ic.cc

@@ -1210,6 +1210,8 @@ Handle<Code> LoadIC::CompileHandler(LookupIterator* lookup,
                               isolate());
         if (!getter->IsJSFunction()) break;
         if (!holder->HasFastProperties()) break;
+        // When debugging we need to go the slow path to flood the accessor.
+        if (!GetSharedFunctionInfo()->debug_info()->IsUndefined()) break;
         Handle<JSFunction> function = Handle<JSFunction>::cast(getter);
         if (!receiver->IsJSObject() && !function->IsBuiltin() &&
             is_sloppy(function->shared()->language_mode())) {
@@ -1786,6 +1788,8 @@ Handle<Code> StoreIC::CompileHandler(LookupIterator* lookup,
           TRACE_GENERIC_IC(isolate(), "StoreIC", "setter not a function");
           break;
         }
+        // When debugging we need to go the slow path to flood the accessor.
+        if (!GetSharedFunctionInfo()->debug_info()->IsUndefined()) break;
         Handle<JSFunction> function = Handle<JSFunction>::cast(setter);
         CallOptimization call_optimization(function);
         NamedStoreHandlerCompiler compiler(isolate(), receiver_map(), holder);