Bug 1526972 - P1: Compress bool state into bit flags. r=miko

Also move to first cache-line (64-bytes) of nsDisplayItem to improve D-cache hit
when accessing mFrame, mItemFlags, etc.

Differential Revision: https://phabricator.services.mozilla.com/D26134

--HG--
extra : moz-landing-system : lando

layout/generic/TextOverflow.cpp

@@ -218,7 +218,7 @@ static void PaintTextShadowCallback(gfxContext* aCtx, nsPoint aShadowOffset,
 void nsDisplayTextOverflowMarker::Paint(nsDisplayListBuilder* aBuilder,
                                         gfxContext* aCtx) {
   DrawTargetAutoDisableSubpixelAntialiasing disable(aCtx->GetDrawTarget(),
-                                                    mDisableSubpixelAA);
+                                                    IsSubpixelAADisabled());
 
   nscolor foregroundColor =
       nsLayoutUtils::GetColor(mFrame, &nsStyleText::mWebkitTextFillColor);

layout/generic/nsBulletFrame.cpp

@@ -646,7 +646,7 @@ void nsDisplayBullet::Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) {
   }
 
   ImgDrawResult result = static_cast<nsBulletFrame*>(mFrame)->PaintBullet(
-      *aCtx, ToReferenceFrame(), GetPaintRect(), flags, mDisableSubpixelAA);
+      *aCtx, ToReferenceFrame(), GetPaintRect(), flags, IsSubpixelAADisabled());
 
   nsDisplayBulletGeometry::UpdateDrawResult(this, result);
 }

layout/generic/nsPageFrame.cpp

@@ -457,7 +457,7 @@ class nsDisplayHeaderFooter final : public nsDisplayItem {
     MOZ_ASSERT(pageFrame, "We should have an nsPageFrame");
 #endif
     static_cast<nsPageFrame*>(mFrame)->PaintHeaderFooter(
-        *aCtx, ToReferenceFrame(), mDisableSubpixelAA);
+        *aCtx, ToReferenceFrame(), IsSubpixelAADisabled());
   }
   NS_DISPLAY_DECL_NAME("HeaderFooter", TYPE_HEADER_FOOTER)
 

layout/painting/RetainedDisplayListBuilder.cpp

@@ -141,8 +141,7 @@ bool RetainedDisplayListBuilder::PreProcessDisplayList(
   MOZ_RELEASE_ASSERT(aList->mOldItems.IsEmpty());
   while (nsDisplayItem* item = aList->RemoveBottom()) {
 #ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
-    item->mMergedItem = false;
-    item->mPreProcessedItem = true;
+    item->SetMergedPreProcessed(false, true);
 #endif
 
     if (item->HasDeletedFrame() || !item->CanBeReused()) {
@@ -496,12 +495,11 @@ class MergeState {
     for (nsDisplayItem* i : *items) {
       if (i->Frame() == aItem->Frame() &&
           i->GetPerFrameKey() == aItem->GetPerFrameKey()) {
-        MOZ_DIAGNOSTIC_ASSERT(!i->mMergedItem);
+        MOZ_DIAGNOSTIC_ASSERT(!i->IsMergedItem());
       }
     }
 
-    aItem->mMergedItem = true;
-    aItem->mPreProcessedItem = false;
+    aItem->SetMergedPreProcessed(true, false);
 #endif
 
     mMergedItems.AppendToTop(aItem);

layout/painting/nsDisplayList.cpp

@@ -135,7 +135,7 @@ void AssertUniqueItem(nsDisplayItem* aItem) {
   for (nsDisplayItem* i : *items) {
     if (i != aItem && !i->HasDeletedFrame() && i->Frame() == aItem->Frame() &&
         i->GetPerFrameKey() == aItem->GetPerFrameKey()) {
-      if (i->mPreProcessedItem) {
+      if (i->IsPreProcessedItem()) {
         continue;
       }
       MOZ_DIAGNOSTIC_ASSERT(false, "Duplicate display item!");
@@ -3171,18 +3171,9 @@ nsDisplayItem::nsDisplayItem(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame)
 nsDisplayItem::nsDisplayItem(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                              const ActiveScrolledRoot* aActiveScrolledRoot)
     : mFrame(aFrame),
+      mItemFlags(),
       mActiveScrolledRoot(aActiveScrolledRoot),
-      mAnimatedGeometryRoot(nullptr),
-      mForceNotVisible(aBuilder->IsBuildingInvisibleItems()),
-      mDisableSubpixelAA(false),
-      mReusedItem(false),
-      mPaintRectValid(false),
-      mCanBeReused(true)
-#ifdef MOZ_DUMP_PAINTING
-      ,
-      mPainted(false)
-#endif
-{
+      mAnimatedGeometryRoot(nullptr) {
   MOZ_COUNT_CTOR(nsDisplayItem);
   if (aBuilder->IsRetainingDisplayList()) {
     mFrame->AddDisplayItem(this);
@@ -3208,9 +3199,12 @@ nsDisplayItem::nsDisplayItem(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
   SetBuildingRect(visible);
 
   const nsStyleDisplay* disp = mFrame->StyleDisplay();
-  mBackfaceIsHidden = mFrame->BackfaceIsHidden(disp);
-  mCombines3DTransformWithAncestors =
-      mFrame->Combines3DTransformWithAncestors(disp);
+  if (mFrame->BackfaceIsHidden(disp)) {
+    mItemFlags += ItemFlag::BackfaceHidden;
+  }
+  if (mFrame->Combines3DTransformWithAncestors(disp)) {
+    mItemFlags += ItemFlag::Combines3DTransformWithAncestors;
+  }
 }
 
 /* static */
@@ -3236,7 +3230,7 @@ bool nsDisplayItem::ComputeVisibility(nsDisplayListBuilder* aBuilder,
 
 bool nsDisplayItem::RecomputeVisibility(nsDisplayListBuilder* aBuilder,
                                         nsRegion* aVisibleRegion) {
-  if (mForceNotVisible && !GetSameCoordinateSystemChildren()) {
+  if (ForceNotVisible() && !GetSameCoordinateSystemChildren()) {
     // mForceNotVisible wants to ensure that this display item doesn't render
     // anything itself. If this item has contents, then we obviously want to
     // render those, so we don't need this check in that case.
@@ -8944,7 +8938,7 @@ void nsDisplayText::Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) {
   AUTO_PROFILER_LABEL("nsDisplayText::Paint", GRAPHICS);
 
   DrawTargetAutoDisableSubpixelAntialiasing disable(aCtx->GetDrawTarget(),
-                                                    mDisableSubpixelAA);
+                                                    IsSubpixelAADisabled());
   RenderToContext(aCtx, aBuilder);
 }
 

layout/painting/nsDisplayList.h

@@ -2183,7 +2183,7 @@ class nsDisplayItem : public nsDisplayItemLink {
   virtual void RestoreState() {
     mClipChain = mState.mClipChain;
     mClip = mState.mClip;
-    mDisableSubpixelAA = false;
+    mItemFlags -= ItemFlag::DisableSubpixelAA;
   }
 
   virtual void RemoveFrame(nsIFrame* aFrame) {
@@ -2215,6 +2215,7 @@ class nsDisplayItem : public nsDisplayItemLink {
    */
   nsDisplayItem(nsDisplayListBuilder* aBuilder, const nsDisplayItem& aOther)
       : mFrame(aOther.mFrame),
+        mItemFlags(),
         mClipChain(aOther.mClipChain),
         mClip(aOther.mClip),
         mActiveScrolledRoot(aOther.mActiveScrolledRoot),
@@ -2222,21 +2223,21 @@ class nsDisplayItem : public nsDisplayItemLink {
         mAnimatedGeometryRoot(aOther.mAnimatedGeometryRoot),
         mToReferenceFrame(aOther.mToReferenceFrame),
         mBuildingRect(aOther.mBuildingRect),
-        mPaintRect(aOther.mPaintRect),
-        mForceNotVisible(aOther.mForceNotVisible),
-        mDisableSubpixelAA(aOther.mDisableSubpixelAA),
-        mReusedItem(false),
-        mBackfaceIsHidden(aOther.mBackfaceIsHidden),
-        mCombines3DTransformWithAncestors(
-            aOther.mCombines3DTransformWithAncestors),
-        mPaintRectValid(false),
-        mCanBeReused(true)
-#ifdef MOZ_DUMP_PAINTING
-        ,
-        mPainted(false)
-#endif
-  {
+        mPaintRect(aOther.mPaintRect) {
     MOZ_COUNT_CTOR(nsDisplayItem);
+    // TODO: It might be better to remove the flags that aren't copied.
+    if (aOther.ForceNotVisible()) {
+      mItemFlags += ItemFlag::ForceNotVisible;
+    }
+    if (aOther.IsSubpixelAADisabled()) {
+      mItemFlags += ItemFlag::DisableSubpixelAA;
+    }
+    if (mFrame->In3DContextAndBackfaceIsHidden()) {
+      mItemFlags += ItemFlag::BackfaceHidden;
+    }
+    if (aOther.Combines3DTransformWithAncestors()) {
+      mItemFlags += ItemFlag::Combines3DTransformWithAncestors;
+    }
   }
 
   struct HitTestState {
@@ -2544,12 +2545,12 @@ class nsDisplayItem : public nsDisplayItemLink {
    * Mark this display item as being painted via
    * FrameLayerBuilder::DrawPaintedLayer.
    */
-  bool Painted() const { return mPainted; }
+  bool Painted() const { return mItemFlags.contains(ItemFlag::Painted); }
 
   /**
    * Check if this display item has been painted.
    */
-  void SetPainted() { mPainted = true; }
+  void SetPainted() { mItemFlags += ItemFlag::Painted; }
 #endif
 
   /**
@@ -2732,14 +2733,16 @@ class nsDisplayItem : public nsDisplayItemLink {
       return;
     }
     mPaintRect = mBuildingRect = aBuildingRect;
-    mPaintRectValid = false;
+    mItemFlags -= ItemFlag::PaintRectValid;
   }
 
   void SetPaintRect(const nsRect& aPaintRect) {
     mPaintRect = aPaintRect;
-    mPaintRectValid = true;
+    mItemFlags += ItemFlag::PaintRectValid;
+  }
+  bool HasPaintRect() const {
+    return mItemFlags.contains(ItemFlag::PaintRectValid);
   }
-  bool HasPaintRect() const { return mPaintRectValid; }
 
   /**
    * Returns the building rect for the children, relative to their
@@ -2765,7 +2768,9 @@ class nsDisplayItem : public nsDisplayItemLink {
    */
   virtual bool CanApplyOpacity() const { return false; }
 
-  bool ForceNotVisible() const { return mForceNotVisible; }
+  bool ForceNotVisible() const {
+    return mItemFlags.contains(ItemFlag::ForceNotVisible);
+  }
 
   /**
    * For debugging and stuff
@@ -2831,9 +2836,11 @@ class nsDisplayItem : public nsDisplayItemLink {
    * Disable usage of component alpha. Currently only relevant for items that
    * have text.
    */
-  void DisableComponentAlpha() { mDisableSubpixelAA = true; }
+  void DisableComponentAlpha() { mItemFlags += ItemFlag::DisableSubpixelAA; }
 
-  bool IsSubpixelAADisabled() const { return mDisableSubpixelAA; }
+  bool IsSubpixelAADisabled() const {
+    return mItemFlags.contains(ItemFlag::DisableSubpixelAA);
+  }
 
   /**
    * Check if we can add async animations to the layer for this display item.
@@ -2869,14 +2876,17 @@ class nsDisplayItem : public nsDisplayItemLink {
   void FuseClipChainUpTo(nsDisplayListBuilder* aBuilder,
                          const ActiveScrolledRoot* aASR);
 
-  bool BackfaceIsHidden() const { return mBackfaceIsHidden; }
+  bool BackfaceIsHidden() const {
+    return mItemFlags.contains(ItemFlag::BackfaceHidden);
+  }
 
   bool Combines3DTransformWithAncestors() const {
-    return mCombines3DTransformWithAncestors;
+    return mItemFlags.contains(ItemFlag::Combines3DTransformWithAncestors);
   }
 
   bool In3DContextAndBackfaceIsHidden() const {
-    return mBackfaceIsHidden && mCombines3DTransformWithAncestors;
+    return mItemFlags.contains(ItemFlag::BackfaceHidden) &&
+           mItemFlags.contains(ItemFlag::Combines3DTransformWithAncestors);
   }
 
   bool HasDifferentFrame(const nsDisplayItem* aOther) const {
@@ -2892,14 +2902,22 @@ class nsDisplayItem : public nsDisplayItemLink {
     return mFrame->GetContent() == aOther->Frame()->GetContent();
   }
 
-  bool IsReused() const { return mReusedItem; }
+  bool IsReused() const { return mItemFlags.contains(ItemFlag::ReusedItem); }
+  void SetReused(bool aReused) {
+    if (aReused) {
+      mItemFlags += ItemFlag::ReusedItem;
+    } else {
+      mItemFlags -= ItemFlag::ReusedItem;
+    }
+  }
 
-  void SetReused(bool aReused) { mReusedItem = aReused; }
-
-  bool CanBeReused() const { return mCanBeReused; }
+  bool CanBeReused() const {
+    return !mItemFlags.contains(ItemFlag::CantBeReused);
+  }
+  void SetCantBeReused() { mItemFlags += ItemFlag::CantBeReused; }
   void DiscardIfOldItem() {
     if (mOldList) {
-      mCanBeReused = false;
+      SetCantBeReused();
     }
   }
   virtual void NotifyUsed(nsDisplayListBuilder* aBuilder) {}
@@ -2975,7 +2993,26 @@ class nsDisplayItem : public nsDisplayItemLink {
   bool ShouldUseAdvancedLayer(LayerManager* aManager, PrefFunc aFunc) const;
   bool CanUseAdvancedLayer(LayerManager* aManager) const;
 
+  enum class ItemFlag {
+    ForceNotVisible,
+    DisableSubpixelAA,
+    CantBeReused,
+    ReusedItem,
+    BackfaceHidden,
+    Combines3DTransformWithAncestors,
+    PaintRectValid,
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    MergedItem,
+    PreProcessedItem,
+#endif
+#ifdef MOZ_DUMP_PAINTING
+    // True if this frame has been painted.
+    Painted,
+#endif
+  };
+
   nsIFrame* mFrame;
+  mozilla::EnumSet<ItemFlag, uint16_t> mItemFlags;
   RefPtr<const DisplayItemClipChain> mClipChain;
   const DisplayItemClip* mClip;
   RefPtr<const ActiveScrolledRoot> mActiveScrolledRoot;
@@ -3009,26 +3046,31 @@ class nsDisplayItem : public nsDisplayItemLink {
 
 #ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
  public:
+  bool IsMergedItem() const {
+    return mItemFlags.contains(ItemFlag::MergedItem);
+  }
+  bool IsPreProcessedItem() const {
+    return mItemFlags.contains(ItemFlag::PreProcessedItem);
+  }
+  void SetMergedPreProcessed(bool aMerged, bool aPreProcessed) {
+    if (aMerged) {
+      mItemFlags += ItemFlag::MergedItem;
+    } else {
+      mItemFlags -= ItemFlag::MergedItem;
+    }
+
+    if (aPreProcessed) {
+      mItemFlags += ItemFlag::PreProcessedItem;
+    } else {
+      mItemFlags -= ItemFlag::PreProcessedItem;
+    }
+  }
+
   uint32_t mOldListKey = 0;
   uint32_t mOldNestingDepth = 0;
-  bool mMergedItem = false;
-  bool mPreProcessedItem = false;
 
  protected:
 #endif
-
-  bool mForceNotVisible;
-  bool mDisableSubpixelAA;
-  bool mReusedItem;
-  bool mBackfaceIsHidden;
-  bool mCombines3DTransformWithAncestors;
-  bool mPaintRectValid;
-  bool mCanBeReused;
-
-#ifdef MOZ_DUMP_PAINTING
-  // True if this frame has been painted.
-  bool mPainted;
-#endif
 };
 
 /**
@@ -4161,7 +4203,9 @@ class nsDisplaySolidColor : public nsDisplaySolidColorBase {
     NS_ASSERTION(NS_GET_A(aColor) > 0,
                  "Don't create invisible nsDisplaySolidColors!");
     MOZ_COUNT_CTOR(nsDisplaySolidColor);
-    mCanBeReused = aCanBeReused;
+    if (!aCanBeReused) {
+      SetCantBeReused();
+    }
   }
 
 #ifdef NS_BUILD_REFCNT_LOGGING

layout/svg/SVGTextFrame.cpp

@@ -2861,7 +2861,7 @@ void nsDisplaySVGText::HitTest(nsDisplayListBuilder* aBuilder,
 
 void nsDisplaySVGText::Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) {
   DrawTargetAutoDisableSubpixelAntialiasing disable(aCtx->GetDrawTarget(),
-                                                    mDisableSubpixelAA);
+                                                    IsSubpixelAADisabled());
 
   uint32_t appUnitsPerDevPixel = mFrame->PresContext()->AppUnitsPerDevPixel();
 

layout/xul/nsTextBoxFrame.cpp

@@ -278,7 +278,7 @@ static void PaintTextShadowCallback(gfxContext* aCtx, nsPoint aShadowOffset,
 void nsDisplayXULTextBox::Paint(nsDisplayListBuilder* aBuilder,
                                 gfxContext* aCtx) {
   DrawTargetAutoDisableSubpixelAntialiasing disable(aCtx->GetDrawTarget(),
-                                                    mDisableSubpixelAA);
+                                                    IsSubpixelAADisabled());
 
   // Paint the text shadow before doing any foreground stuff
   nsRect drawRect =

layout/xul/tree/nsTreeBodyFrame.cpp

@@ -2498,7 +2498,7 @@ class nsDisplayTreeBody final : public nsDisplayItem {
                      gfxContext* aCtx) override {
     MOZ_ASSERT(aBuilder);
     DrawTargetAutoDisableSubpixelAntialiasing disable(aCtx->GetDrawTarget(),
-                                                      mDisableSubpixelAA);
+                                                      IsSubpixelAADisabled());
 
     ImgDrawResult result = static_cast<nsTreeBodyFrame*>(mFrame)->PaintTreeBody(
         *aCtx, GetPaintRect(), ToReferenceFrame(), aBuilder);