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.

6 files changed, 24 insertions, 61 deletions

diff --git a/layout/mathml/nsMathMLmtableFrame.cpp b/layout/mathml/nsMathMLmtableFrame.cpp
index fd184e6375..1ff8a28ef0 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 5cb4fc4a2f..725991c179 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 b744b51752..ac7be58d76 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 e761d76be1..a366b150eb 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 2862bb201f..d1736995ef 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 e8dad5c20f..ea527b3c59 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;