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.

4 files changed, 24 insertions, 18 deletions

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;