Hydrogen should recognize literal smi arrays as fast literals.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/726423002

Cr-Commit-Position: refs/heads/master@{#25387}

src/hydrogen.cc

@@ -5529,7 +5529,7 @@ static bool IsFastLiteral(Handle<JSObject> boilerplate,
   Handle<FixedArrayBase> elements(boilerplate->elements());
   if (elements->length() > 0 &&
       elements->map() != isolate->heap()->fixed_cow_array_map()) {
-    if (boilerplate->HasFastObjectElements()) {
+    if (boilerplate->HasFastSmiOrObjectElements()) {
       Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
       int length = elements->length();
       for (int i = 0; i < length; i++) {
@@ -5790,17 +5790,13 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
                         Add<HConstant>(constants),
                         Add<HConstant>(flags));
 
-    // TODO(mvstanton): Consider a flag to turn off creation of any
-    // AllocationMementos for this call: we are in crankshaft and should have
-    // learned enough about transition behavior to stop emitting mementos.
     Runtime::FunctionId function_id = Runtime::kCreateArrayLiteral;
     literal = Add<HCallRuntime>(isolate()->factory()->empty_string(),
                                 Runtime::FunctionForId(function_id),
                                 4);
 
-    // De-opt if elements kind changed from boilerplate_elements_kind.
-    Handle<Map> map = Handle<Map>(boilerplate_object->map(), isolate());
-    literal = Add<HCheckMaps>(literal, map);
+    // Register to deopt if the boilerplate ElementsKind changes.
+    AllocationSite::RegisterForDeoptOnTransitionChange(site, top_info());
   }
 
   // The array is expected in the bailout environment during computation
@@ -9349,8 +9345,7 @@ void HOptimizedGraphBuilder::BuildInlinedCallArray(
   HValue* constructor = environment()->ExpressionStackAt(argument_count);
 
   // Register on the site for deoptimization if the transition feedback changes.
-  AllocationSite::AddDependentCompilationInfo(
-      site, AllocationSite::TRANSITIONS, top_info());
+  AllocationSite::RegisterForDeoptOnTransitionChange(site, top_info());
   ElementsKind kind = site->GetElementsKind();
   HInstruction* site_instruction = Add<HConstant>(site);
 
@@ -9480,9 +9475,8 @@ void HOptimizedGraphBuilder::VisitCallNew(CallNew* expr) {
         Handle<AllocationSite> allocation_site = expr->allocation_site();
         allocation_mode = HAllocationMode(allocation_site);
         // Take a dependency on allocation site.
-        AllocationSite::AddDependentCompilationInfo(allocation_site,
-                                                    AllocationSite::TENURING,
-                                                    top_info());
+        AllocationSite::RegisterForDeoptOnTenureChange(allocation_site,
+                                                       top_info());
       }
     }
 
@@ -10525,8 +10519,7 @@ HValue* HGraphBuilder::BuildBinaryOperation(
     if (!allocation_mode.feedback_site().is_null()) {
       DCHECK(!graph()->info()->IsStub());
       Handle<AllocationSite> site(allocation_mode.feedback_site());
-      AllocationSite::AddDependentCompilationInfo(
-          site, AllocationSite::TENURING, top_info());
+      AllocationSite::RegisterForDeoptOnTenureChange(site, top_info());
     }
 
     // Inline the string addition into the stub when creating allocation
@@ -11121,13 +11114,14 @@ HInstruction* HOptimizedGraphBuilder::BuildFastLiteral(
       boilerplate_object->map()->instance_size());
 
   PretenureFlag pretenure_flag = NOT_TENURED;
+  Handle<AllocationSite> site(site_context->current());
   if (FLAG_allocation_site_pretenuring) {
     pretenure_flag = site_context->current()->GetPretenureMode();
-    Handle<AllocationSite> site(site_context->current());
-    AllocationSite::AddDependentCompilationInfo(
-        site, AllocationSite::TENURING, top_info());
+    AllocationSite::RegisterForDeoptOnTenureChange(site, top_info());
   }
 
+  AllocationSite::RegisterForDeoptOnTransitionChange(site, top_info());
+
   HInstruction* object = Add<HAllocate>(object_size_constant, type,
       pretenure_flag, instance_type, site_context->current());
 

src/objects-inl.h

@@ -1652,21 +1652,6 @@ inline bool AllocationSite::CanTrack(InstanceType type) {
 }
 
 
-inline DependentCode::DependencyGroup AllocationSite::ToDependencyGroup(
-    Reason reason) {
-  switch (reason) {
-    case TENURING:
-      return DependentCode::kAllocationSiteTenuringChangedGroup;
-      break;
-    case TRANSITIONS:
-      return DependentCode::kAllocationSiteTransitionChangedGroup;
-      break;
-  }
-  UNREACHABLE();
-  return DependentCode::kAllocationSiteTransitionChangedGroup;
-}
-
-
 inline void AllocationSite::set_memento_found_count(int count) {
   int value = pretenure_data()->value();
   // Verify that we can count more mementos than we can possibly find in one

src/objects.cc

@@ -12959,10 +12959,32 @@ void AllocationSite::DigestTransitionFeedback(Handle<AllocationSite> site,
 
 
 // static
-void AllocationSite::AddDependentCompilationInfo(Handle<AllocationSite> site,
-                                                 Reason reason,
-                                                 CompilationInfo* info) {
-  DependentCode::DependencyGroup group = site->ToDependencyGroup(reason);
+void AllocationSite::RegisterForDeoptOnTenureChange(Handle<AllocationSite> site,
+                                                    CompilationInfo* info) {
+  AddDependentCompilationInfo(
+      site, DependentCode::kAllocationSiteTenuringChangedGroup, info);
+}
+
+
+// static
+void AllocationSite::RegisterForDeoptOnTransitionChange(
+    Handle<AllocationSite> site, CompilationInfo* info) {
+  // Do nothing if the object doesn't have any useful element transitions left.
+  ElementsKind kind =
+      site->SitePointsToLiteral()
+          ? JSObject::cast(site->transition_info())->GetElementsKind()
+          : site->GetElementsKind();
+  if (AllocationSite::GetMode(kind) == TRACK_ALLOCATION_SITE) {
+    AddDependentCompilationInfo(
+        site, DependentCode::kAllocationSiteTransitionChangedGroup, info);
+  }
+}
+
+
+// static
+void AllocationSite::AddDependentCompilationInfo(
+    Handle<AllocationSite> site, DependentCode::DependencyGroup group,
+    CompilationInfo* info) {
   Handle<DependentCode> dep(site->dependent_code());
   Handle<DependentCode> codes =
       DependentCode::Insert(dep, group, info->object_wrapper());

src/objects.h

@@ -8353,14 +8353,11 @@ class AllocationSite: public Struct {
   static void DigestTransitionFeedback(Handle<AllocationSite> site,
                                        ElementsKind to_kind);
 
-  enum Reason {
-    TENURING,
-    TRANSITIONS
-  };
+  static void RegisterForDeoptOnTenureChange(Handle<AllocationSite> site,
+                                             CompilationInfo* info);
 
-  static void AddDependentCompilationInfo(Handle<AllocationSite> site,
-                                          Reason reason,
-                                          CompilationInfo* info);
+  static void RegisterForDeoptOnTransitionChange(Handle<AllocationSite> site,
+                                                 CompilationInfo* info);
 
   DECLARE_PRINTER(AllocationSite)
   DECLARE_VERIFIER(AllocationSite)
@@ -8392,7 +8389,10 @@ class AllocationSite: public Struct {
                               kSize> BodyDescriptor;
 
  private:
-  inline DependentCode::DependencyGroup ToDependencyGroup(Reason reason);
+  static void AddDependentCompilationInfo(Handle<AllocationSite> site,
+                                          DependentCode::DependencyGroup group,
+                                          CompilationInfo* info);
+
   bool PretenuringDecisionMade() {
     return pretenure_decision() != kUndecided;
   }