Shrink WebCore::Pair

https://bugs.webkit.org/show_bug.cgi?id=187450

Reviewed by Sam Weinig.

Move m_encoding to pack in with m_refCount and remove the virtual destructor,
shrinking the class from 40 to 24 bytes.
Also make the enum take only a byte, in case it gets used elsewhere

There are about 500 Pairs on nytimes.com, so this memory saving is non-trivial.

* css/Pair.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@233652 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index e0cefa8..3d7530c 100644 (file)
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,18 @@
+2018-07-09  Simon Fraser  <simon.fraser@apple.com>
+
+        Shrink WebCore::Pair
+        https://bugs.webkit.org/show_bug.cgi?id=187450
+
+        Reviewed by Sam Weinig.
+
+        Move m_encoding to pack in with m_refCount and remove the virtual destructor,
+        shrinking the class from 40 to 24 bytes.
+        Also make the enum take only a byte, in case it gets used elsewhere
+        
+        There are about 500 Pairs on nytimes.com, so this memory saving is non-trivial.
+
+        * css/Pair.h:
+
 2018-07-09  Yusuke Suzuki  <utatane.tea@gmail.com>
 
         [WebCore] Annotate classes with WTF_MAKE_FAST_ALLOCATED as much as possible

diff --git a/Source/WebCore/css/Pair.h b/Source/WebCore/css/Pair.h
index 56ad0d2..e0ef452 100644 (file)
--- a/Source/WebCore/css/Pair.h
+++ b/Source/WebCore/css/Pair.h
@@ -30,9 +30,9 @@ class CSSPrimitiveValue;
 // and border-spacing (all of which are space-separated sets of two values).  At the moment we are only using it for
 // border-radius and background-size, but (FIXME) border-spacing and background-position could be converted over to use
 // it (eliminating some extra -webkit- internal properties).
-class Pair final : public RefCounted<Pair> {
+class Pair : public RefCounted<Pair> {
 public:
-    enum class IdenticalValueEncoding {
+    enum class IdenticalValueEncoding : uint8_t {
         DoNotCoalesce,
         Coalesce
     };
@@ -45,8 +45,6 @@ public:
     {
         return adoptRef(*new Pair(WTFMove(first), WTFMove(second), encoding));
     }
-    virtual ~Pair() = default;
-
     CSSPrimitiveValue* first() const { return m_first.get(); }
     CSSPrimitiveValue* second() const { return m_second.get(); }
 
@@ -62,12 +60,20 @@ public:
     bool equals(const Pair& other) const { return compareCSSValuePtr(m_first, other.m_first) && compareCSSValuePtr(m_second, other.m_second); }
 
 private:
-    Pair(RefPtr<CSSPrimitiveValue>&& first, RefPtr<CSSPrimitiveValue>&& second) : m_first(WTFMove(first)), m_second(WTFMove(second)) { }
-    Pair(RefPtr<CSSPrimitiveValue>&& first, RefPtr<CSSPrimitiveValue>&& second, IdenticalValueEncoding encoding) : m_first(WTFMove(first)), m_second(WTFMove(second)), m_encoding(encoding) { }
+    Pair(RefPtr<CSSPrimitiveValue>&& first, RefPtr<CSSPrimitiveValue>&& second)
+        : m_first(WTFMove(first))
+        , m_second(WTFMove(second))
+    { }
+
+    Pair(RefPtr<CSSPrimitiveValue>&& first, RefPtr<CSSPrimitiveValue>&& second, IdenticalValueEncoding encoding)
+        : m_encoding(encoding)
+        , m_first(WTFMove(first))
+        , m_second(WTFMove(second))
+    { }
 
+    IdenticalValueEncoding m_encoding { IdenticalValueEncoding::Coalesce };
     RefPtr<CSSPrimitiveValue> m_first;
     RefPtr<CSSPrimitiveValue> m_second;
-    IdenticalValueEncoding m_encoding { IdenticalValueEncoding::Coalesce };
 };
 
 } // namespace