Issue #1386 - Devirtualize GetRowSpan/GetColSpan

It's at ~1.5% on the perf log for the Netflix use case, which seems a bit too much.

7 files changed, 41 insertions, 64 deletions

diff --git a/dom/mathml/nsMathMLElement.cpp b/dom/mathml/nsMathMLElement.cpp
index d6aef876c..2be931682 100644
--- a/dom/mathml/nsMathMLElement.cpp
+++ b/dom/mathml/nsMathMLElement.cpp
@@ -9,6 +9,7 @@
 #include "base/compiler_specific.h"
 #include "mozilla/ArrayUtils.h"
 #include "nsGkAtoms.h"
+#include "nsITableCellLayout.h" // for MAX_COLSPAN / MAX_ROWSPAN
 #include "nsCRT.h"
 #include "nsLayoutStylesheetCache.h"
 #include "nsRuleData.h"
@@ -150,8 +151,9 @@ nsMathMLElement::ParseAttribute(int32_t aNamespaceID,
                                 const nsAString& aValue,
                                 nsAttrValue& aResult)
 {
+  MOZ_ASSERT(IsMathMLElement());
   if (aNamespaceID == kNameSpaceID_None) {
-    if (IsMathMLElement(nsGkAtoms::math) && aAttribute == nsGkAtoms::mode) {
+    if (mNodeInfo->Equals(nsGkAtoms::math) && aAttribute == nsGkAtoms::mode) {
       WarnDeprecated(nsGkAtoms::mode->GetUTF16String(),
                      nsGkAtoms::display->GetUTF16String(), OwnerDoc());
     }
@@ -165,6 +167,16 @@ nsMathMLElement::ParseAttribute(int32_t aNamespaceID,
         aAttribute == nsGkAtoms::mathbackground_) {
       return aResult.ParseColor(aValue);
     }
+    if (mNodeInfo->Equals(nsGkAtoms::mtd_)) {
+      if (aAttribute == nsGkAtoms::columnspan_) {
+        aResult.ParseClampedNonNegativeInt(aValue, 1, 1, MAX_COLSPAN);
+        return true;
+      }
+      if (aAttribute == nsGkAtoms::rowspan) {
+        aResult.ParseClampedNonNegativeInt(aValue, 1, 0, MAX_ROWSPAN);
+        return true;
+      }
+    }
   }
 
   return nsMathMLElementBase::ParseAttribute(aNamespaceID, aAttribute,
@@ -209,6 +221,8 @@ static Element::MappedAttributeEntry sDirStyles[] = {
 bool
 nsMathMLElement::IsAttributeMapped(const nsIAtom* aAttribute) const
 {
+  MOZ_ASSERT(IsMathMLElement());
+
   static const MappedAttributeEntry* const mtableMap[] = {
     sMtableStyles,
     sCommonPresStyles
@@ -240,10 +254,10 @@ nsMathMLElement::IsAttributeMapped(const nsIAtom* aAttribute) const
   if (IsAnyOfMathMLElements(nsGkAtoms::mstyle_, nsGkAtoms::math))
     return FindAttributeDependence(aAttribute, mstyleMap);
 
-  if (IsMathMLElement(nsGkAtoms::mtable_))
+  if (mNodeInfo->Equals(nsGkAtoms::mtable_))
     return FindAttributeDependence(aAttribute, mtableMap);
 
-  if (IsMathMLElement(nsGkAtoms::mrow_))
+  if (mNodeInfo->Equals(nsGkAtoms::mrow_))
     return FindAttributeDependence(aAttribute, mrowMap);
 
   if (IsAnyOfMathMLElements(nsGkAtoms::maction_,
diff --git a/layout/mathml/nsMathMLmtableFrame.cpp b/layout/mathml/nsMathMLmtableFrame.cpp
index fd184e637..1ff8a28ef 100644
--- a/layout/mathml/nsMathMLmtableFrame.cpp
+++ b/layout/mathml/nsMathMLmtableFrame.cpp
@@ -1160,47 +1160,6 @@ nsMathMLmtdFrame::Init(nsIContent*       aContent,
   RemoveStateBits(NS_FRAME_FONT_INFLATION_FLOW_ROOT);
 }
 
-int32_t
-nsMathMLmtdFrame::GetRowSpan()
-{
-  int32_t rowspan = 1;
-
-  // Don't look at the content's rowspan if we're not an mtd or a pseudo cell.
-  if (mContent->IsMathMLElement(nsGkAtoms::mtd_) &&
-      !StyleContext()->GetPseudo()) {
-    nsAutoString value;
-    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::rowspan, value);
-    if (!value.IsEmpty()) {
-      nsresult error;
-      rowspan = value.ToInteger(&error);
-      if (NS_FAILED(error) || rowspan < 0)
-        rowspan = 1;
-      rowspan = std::min(rowspan, MAX_ROWSPAN);
-    }
-  }
-  return rowspan;
-}
-
-int32_t
-nsMathMLmtdFrame::GetColSpan()
-{
-  int32_t colspan = 1;
-
-  // Don't look at the content's colspan if we're not an mtd or a pseudo cell.
-  if (mContent->IsMathMLElement(nsGkAtoms::mtd_) &&
-      !StyleContext()->GetPseudo()) {
-    nsAutoString value;
-    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::columnspan_, value);
-    if (!value.IsEmpty()) {
-      nsresult error;
-      colspan = value.ToInteger(&error);
-      if (NS_FAILED(error) || colspan <= 0 || colspan > MAX_COLSPAN)
-        colspan = 1;
-    }
-  }
-  return colspan;
-}
-
 nsresult
 nsMathMLmtdFrame::AttributeChanged(int32_t  aNameSpaceID,
                                    nsIAtom* aAttribute,
diff --git a/layout/mathml/nsMathMLmtableFrame.h b/layout/mathml/nsMathMLmtableFrame.h
index 5cb4fc4a2..725991c17 100644
--- a/layout/mathml/nsMathMLmtableFrame.h
+++ b/layout/mathml/nsMathMLmtableFrame.h
@@ -257,8 +257,6 @@ public:
                                   nsDisplayListBuilder*   aBuilder,
                                   const nsDisplayListSet& aLists) override;
 
-  virtual int32_t GetRowSpan() override;
-  virtual int32_t GetColSpan() override;
   virtual bool IsFrameOfType(uint32_t aFlags) const override
   {
     return nsTableCellFrame::IsFrameOfType(aFlags & ~(nsIFrame::eMathML));
diff --git a/layout/tables/celldata.h b/layout/tables/celldata.h
index b744b5175..ac7be58d7 100644
--- a/layout/tables/celldata.h
+++ b/layout/tables/celldata.h
@@ -6,6 +6,7 @@
 #define CellData_h__
 
 #include "nsISupports.h"
+#include "nsITableCellLayout.h" // for MAX_COLSPAN / MAX_ROWSPAN
 #include "nsCoord.h"
 #include "mozilla/gfx/Types.h"
 #include "mozilla/WritingModes.h"
@@ -15,11 +16,6 @@ class nsTableCellFrame;
 class nsCellMap;
 class BCCellData;
 
-
-#define MAX_ROWSPAN 65534 // the cellmap can not handle more.
-#define MAX_COLSPAN 1000 // limit as IE and opera do.  If this ever changes,
-                         // change COL_SPAN_OFFSET/COL_SPAN_SHIFT accordingly.
-
 /**
   * Data stored by nsCellMap to rationalize rowspan and colspan cells.
   */
diff --git a/layout/tables/nsITableCellLayout.h b/layout/tables/nsITableCellLayout.h
index e761d76be..a366b150e 100644
--- a/layout/tables/nsITableCellLayout.h
+++ b/layout/tables/nsITableCellLayout.h
@@ -7,6 +7,10 @@
 
 #include "nsQueryFrame.h"
 
+#define MAX_ROWSPAN 65534 // the cellmap can not handle more.
+#define MAX_COLSPAN 1000 // limit as IE and opera do.  If this ever changes,
+// change COL_SPAN_OFFSET/COL_SPAN_SHIFT accordingly.
+
 /**
  * nsITableCellLayout
  * interface for layout objects that act like table cells.
diff --git a/layout/tables/nsTableCellFrame.cpp b/layout/tables/nsTableCellFrame.cpp
index 2862bb201..d1736995e 100644
--- a/layout/tables/nsTableCellFrame.cpp
+++ b/layout/tables/nsTableCellFrame.cpp
@@ -711,16 +711,18 @@ nsTableCellFrame::GetCellBaseline() const
          borderPadding;
 }
 
-int32_t nsTableCellFrame::GetRowSpan()
+int32_t
+nsTableCellFrame::GetRowSpan()
 {
   int32_t rowSpan=1;
-  nsGenericHTMLElement *hc = nsGenericHTMLElement::FromContent(mContent);
 
   // Don't look at the content's rowspan if we're a pseudo cell
-  if (hc && !StyleContext()->GetPseudo()) {
-    const nsAttrValue* attr = hc->GetParsedAttr(nsGkAtoms::rowspan);
+  if (!StyleContext()->GetPseudo()) {
+    dom::Element* elem = mContent->AsElement();
+    const nsAttrValue* attr = elem->GetParsedAttr(nsGkAtoms::rowspan);
     // Note that we don't need to check the tag name, because only table cells
-    // and table headers parse the "rowspan" attribute into an integer.
+    // (including MathML <mtd>) and table headers parse the "rowspan" attribute
+    // into an integer.
     if (attr && attr->Type() == nsAttrValue::eInteger) {
        rowSpan = attr->GetIntegerValue();
     }
@@ -728,16 +730,20 @@ int32_t nsTableCellFrame::GetRowSpan()
   return rowSpan;
 }
 
-int32_t nsTableCellFrame::GetColSpan()
+int32_t 
+nsTableCellFrame::GetColSpan()
 {
   int32_t colSpan=1;
-  nsGenericHTMLElement *hc = nsGenericHTMLElement::FromContent(mContent);
 
   // Don't look at the content's colspan if we're a pseudo cell
-  if (hc && !StyleContext()->GetPseudo()) {
-    const nsAttrValue* attr = hc->GetParsedAttr(nsGkAtoms::colspan);
+  if (!StyleContext()->GetPseudo()) {
+    dom::Element* elem = mContent->AsElement();
+    const nsAttrValue* attr = elem->GetParsedAttr(
+      MOZ_UNLIKELY(elem->IsMathMLElement()) ? nsGkAtoms::columnspan_
+                                              : nsGkAtoms::colspan);
     // Note that we don't need to check the tag name, because only table cells
-    // and table headers parse the "colspan" attribute into an integer.
+    // (including MathML <mtd>) and table headers parse the "colspan" attribute
+    // into an integer.
     if (attr && attr->Type() == nsAttrValue::eInteger) {
        colSpan = attr->GetIntegerValue();
     }
diff --git a/layout/tables/nsTableCellFrame.h b/layout/tables/nsTableCellFrame.h
index e8dad5c20..ea527b3c5 100644
--- a/layout/tables/nsTableCellFrame.h
+++ b/layout/tables/nsTableCellFrame.h
@@ -165,11 +165,11 @@ public:
 
   /**
    * return the cell's specified row span. this is what was specified in the
-   * content model or in the style info, and is always >= 1.
+   * content model or in the style info, and is always >= 0.
    * to get the effective row span (the actual value that applies), use GetEffectiveRowSpan()
    * @see nsTableFrame::GetEffectiveRowSpan()
    */
-  virtual int32_t GetRowSpan();
+  int32_t GetRowSpan();
 
   // there is no set row index because row index depends on the cell's parent row only
 
@@ -191,7 +191,7 @@ public:
    * to get the effective col span (the actual value that applies), use GetEffectiveColSpan()
    * @see nsTableFrame::GetEffectiveColSpan()
    */
-  virtual int32_t GetColSpan();
+  int32_t GetColSpan();
 
   /** return the cell's column index (starting at 0 for the first column) */
   virtual nsresult GetColIndex(int32_t &aColIndex) const override;