Changeset 177979 in webkit

Timestamp:

Jan 6, 2015, 11:37:42 AM (10 years ago)

Author:

Antti Koivisto

Message:

REGRESSION (r177876): 35% regression in Parser/html5-full-render
​https://bugs.webkit.org/show_bug.cgi?id=140123

Reviewed by Darin Adler.

Resolving system fallbacks is extremely slow. GlyphPageTree used to cache them globally.

This patch brings back a simple global cache for system fallbacks.

• platform/graphics/SimpleFontData.cpp:

(WebCore::SimpleFontData::~SimpleFontData):
(WebCore::systemFallbackCache):
(WebCore::SimpleFontData::systemFallbackFontDataForCharacter):
(WebCore::SimpleFontData::removeFromSystemFallbackCache):

• platform/graphics/SimpleFontData.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/SimpleFontData.cpp (modified) (3 diffs)
• platform/graphics/SimpleFontData.h (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2015-01-06  Antti Koivisto  <antti@apple.com>
+
+        REGRESSION (r177876): 35% regression in Parser/html5-full-render
+        https://bugs.webkit.org/show_bug.cgi?id=140123
+
+        Reviewed by Darin Adler.
+
+        Resolving system fallbacks is extremely slow. GlyphPageTree used to cache them globally.
+
+        This patch brings back a simple global cache for system fallbacks.
+
+        * platform/graphics/SimpleFontData.cpp:
+        (WebCore::SimpleFontData::~SimpleFontData):
+        (WebCore::systemFallbackCache):
+        (WebCore::SimpleFontData::systemFallbackFontDataForCharacter):
+        (WebCore::SimpleFontData::removeFromSystemFallbackCache):
+        * platform/graphics/SimpleFontData.h:
+
 2015-01-06  Antti Koivisto  <antti@apple.com>
 

trunk/Source/WebCore/platform/graphics/SimpleFontData.cpp

@@ -157 +157 @@
     if (!isSVGFont())
         platformDestroy();
+
+    removeFromSystemFallbackCache();
 }
 
@@ -197 +199 @@
     unsigned bufferLength;
     // Fill in a buffer with the entire "page" of characters that we want to look up glyphs for.
-    if (start < 0x10000) {
+    if (U_IS_BMP(start)) {
         bufferLength = GlyphPage::size;
         for (unsigned i = 0; i < GlyphPage::size; i++)
@@ -428 +430 @@
 }
 
-RefPtr<SimpleFontData> SimpleFontData::systemFallbackFontDataForCharacter(UChar32 c, const FontDescription& description, bool isForPlatformFont) const
-{
-    UChar codeUnits[2];
-    int codeUnitsLength;
-    if (c <= 0xFFFF) {
-        codeUnits[0] = Font::normalizeSpaces(c);
-        codeUnitsLength = 1;
-    } else {
-        codeUnits[0] = U16_LEAD(c);
-        codeUnits[1] = U16_TRAIL(c);
-        codeUnitsLength = 2;
-    }
-
-    return fontCache().systemFallbackForCharacters(description, this, isForPlatformFont, codeUnits, codeUnitsLength);
+// FontDatas are not refcounted to avoid cycles.
+typedef HashMap<std::pair<UChar32, unsigned>, SimpleFontData*> CharacterFallbackMap;
+typedef HashMap<const SimpleFontData*, CharacterFallbackMap> SystemFallbackCache;
+
+static SystemFallbackCache& systemFallbackCache()
+{
+    static NeverDestroyed<SystemFallbackCache> map;
+    return map.get();
+}
+
+RefPtr<SimpleFontData> SimpleFontData::systemFallbackFontDataForCharacter(UChar32 character, const FontDescription& description, bool isForPlatformFont) const
+{
+    auto fontAddResult = systemFallbackCache().add(this, CharacterFallbackMap());
+
+    auto key = std::make_pair(character, isForPlatformFont);
+    auto characterAddResult = fontAddResult.iterator->value.add(key, nullptr);
+
+    SimpleFontData*& fallbackFontData = characterAddResult.iterator->value;
+
+    if (!fallbackFontData) {
+        UChar codeUnits[2];
+        int codeUnitsLength;
+        if (U_IS_BMP(character)) {
+            codeUnits[0] = Font::normalizeSpaces(character);
+            codeUnitsLength = 1;
+        } else {
+            codeUnits[0] = U16_LEAD(character);
+            codeUnits[1] = U16_TRAIL(character);
+            codeUnitsLength = 2;
+        }
+
+        fallbackFontData = fontCache().systemFallbackForCharacters(description, this, false, codeUnits, codeUnitsLength).get();
+        if (fallbackFontData)
+            fallbackFontData->m_isUsedInSystemFallbackCache = true;
+    }
+
+    return fallbackFontData;
+}
+
+void SimpleFontData::removeFromSystemFallbackCache()
+{
+    systemFallbackCache().remove(this);
+
+    if (!m_isUsedInSystemFallbackCache)
+        return;
+
+    for (auto& characterMap : systemFallbackCache().values()) {
+        Vector<std::pair<UChar32, unsigned>, 512> toRemove;
+        for (auto& entry : characterMap) {
+            if (entry.value == this)
+                toRemove.append(entry.key);
+        }
+        for (auto& key : toRemove)
+            characterMap.remove(key);
+    }
 }
 

trunk/Source/WebCore/platform/graphics/SimpleFontData.h

@@ -233 +233 @@
     virtual const SimpleFontData& simpleFontDataForFirstRange() const override;
 
+    void removeFromSystemFallbackCache();
+
 #if PLATFORM(WIN)
     void initGDIFont();
@@ -264 +266 @@
     bool m_isTextOrientationFallback;
     bool m_isBrokenIdeographFallback;
+
+    bool m_isUsedInSystemFallbackCache { false };
+
     mutable RefPtr<OpenTypeMathData> m_mathData;
 #if ENABLE(OPENTYPE_VERTICAL)