Bug 251774

Summary: Optimize layout of Font to reduce padding
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: TextAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: darin, heycam, mmaxfield, simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Local Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch none

Description Simon Fraser (smfr) 2023-02-05 21:56:23 PST 
OpenSource % /usr/bin/python3 ./Tools/Scripts/dump-class-layout -c Release WebCore Font                      
  +0 <1272> WebCore::Font
  +0 <  4>     WTF::RefCounted<WebCore::Font, std::__1::default_delete<WebCore::Font> > WTF::RefCounted<WebCore::Font, std::__1::default_delete<WebCore::Font> >
  +0 <  4>         WTF::RefCountedBase WTF::RefCountedBase
  +0 <  4>           unsigned int m_refCount
  +4 < 68>     WebCore::FontMetrics m_fontMetrics
  +4 <  4>       unsigned int m_unitsPerEm
  +8 <  4>       float m_floatAscent
 +12 <  4>       float m_floatDescent
 +16 <  4>       float m_floatLineGap
 +20 <  4>       float m_floatLineSpacing
 +24 <  4>       float m_floatCapHeight
 +28 <  4>       int m_intAscent
 +32 <  4>       int m_intDescent
 +36 <  4>       int m_intLineGap
 +40 <  4>       int m_intLineSpacing
 +44 <  4>       int m_intCapHeight
 +48 <  8>         std::__1::optional<float> m_zeroWidth
 +48 <  8>             std::__1::__optional_move_assign_base<float, true> std::__1::__optional_move_assign_base<float, true>
 +48 <  8>                 std::__1::__optional_copy_assign_base<float, true> std::__1::__optional_copy_assign_base<float, true>
 +48 <  8>                     std::__1::__optional_move_base<float, true> std::__1::__optional_move_base<float, true>
 +48 <  8>                         std::__1::__optional_copy_base<float, true> std::__1::__optional_copy_base<float, true>
 +48 <  8>                             std::__1::__optional_storage_base<float, false> std::__1::__optional_storage_base<float, false>
 +48 <  8>                                 std::__1::__optional_destruct_base<float, true> std::__1::__optional_destruct_base<float, true>
 +48 <  4>                                   std::__1::__optional_destruct_base<float, true>::(anonymous union) None
 +52 <  1>                                   bool __engaged_
 +48 <  1>             std::__1::__optional_sfinae_ctor_base_t<float> std::__1::__optional_sfinae_ctor_base_t<float>
 +48 <  1>             std::__1::__optional_sfinae_assign_base_t<float> std::__1::__optional_sfinae_assign_base_t<float>
 +53 <  3>       <PADDING: 3 bytes>
 +56 <  4>       float m_ideogramWidth
 +60 <  4>       float m_xHeight
 +64 <  4>       float m_underlinePosition
 +68 <  4>       float m_underlineThickness
 +72 <  4>   float m_maxCharWidth
 +76 <  4>   float m_avgCharWidth
 +80 < 56>     const WebCore::FontPlatformData m_platformData
 +80 <  8>         WTF::RetainPtr<const __CTFont *> m_font
 +80 <  8>           CFTypeRef m_ptr
 +88 <  8>         WTF::RetainPtr<const __CTFont *> m_ctFont
 +88 <  8>           CFTypeRef m_ptr
 +96 <  4>       float m_size
+100 <  1>       WebCore::FontOrientation m_orientation
+101 <  1>       WebCore::FontWidthVariant m_widthVariant
+102 <  1>       WebCore::TextRenderingMode m_textRenderingMode
+103 <  1>       <PADDING: 1 byte>
+104 < 24>         std::__1::optional<WebCore::FontPlatformData::CreationData> m_creationData
+104 < 24>             std::__1::__optional_move_assign_base<WebCore::FontPlatformData::CreationData, false> std::__1::__optional_move_assign_base<WebCore::FontPlatformData::CreationData, false>
+104 < 24>                 std::__1::__optional_copy_assign_base<WebCore::FontPlatformData::CreationData, false> std::__1::__optional_copy_assign_base<WebCore::FontPlatformData::CreationData, false>
+104 < 24>                     std::__1::__optional_move_base<WebCore::FontPlatformData::CreationData, false> std::__1::__optional_move_base<WebCore::FontPlatformData::CreationData, false>
+104 < 24>                         std::__1::__optional_copy_base<WebCore::FontPlatformData::CreationData, false> std::__1::__optional_copy_base<WebCore::FontPlatformData::CreationData, false>
+104 < 24>                             std::__1::__optional_storage_base<WebCore::FontPlatformData::CreationData, false> std::__1::__optional_storage_base<WebCore::FontPlatformData::CreationData, false>
+104 < 24>                                 std::__1::__optional_destruct_base<WebCore::FontPlatformData::CreationData, false> std::__1::__optional_destruct_base<WebCore::FontPlatformData::CreationData, false>
+104 < 16>                                   std::__1::__optional_destruct_base<WebCore::FontPlatformData::CreationData, false>::(anonymous union) None
+120 <  1>                                   bool __engaged_
+104 <  1>             std::__1::__optional_sfinae_ctor_base_t<WebCore::FontPlatformData::CreationData> std::__1::__optional_sfinae_ctor_base_t<WebCore::FontPlatformData::CreationData>
+104 <  1>             std::__1::__optional_sfinae_assign_base_t<WebCore::FontPlatformData::CreationData> std::__1::__optional_sfinae_assign_base_t<WebCore::FontPlatformData::CreationData>
+121 <  7>       <PADDING: 7 bytes>
+128 <  1>       bool m_syntheticBold
+129 <  1>       bool m_syntheticOblique
+130 <  1>       bool m_isColorBitmapFont
+131 <  1>       bool m_isHashTableDeletedValue
+132 <  1>       bool m_isSystemFont
+133 <  1>       bool m_hasVariations
+134 <  2>   <PADDING: 2 bytes>
+136 <  8>     WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> > m_glyphPageZero
+136 <  8>       WTF::RawPtrTraits<WebCore::GlyphPage>::StorageType m_ptr
+144 <  8>     WTF::HashMap<unsigned int, WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> >, WTF::DefaultHash<unsigned int>, WTF::HashTraits<unsigned int>, WTF::HashTraits<WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> > >, WTF::HashTableTraits> m_glyphPages
+144 <  8>         WTF::HashMap<unsigned int, WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> >, WTF::DefaultHash<unsigned int>, WTF::HashTraits<unsigned int>, WTF::HashTraits<WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> > >, WTF::HashTableTraits>::HashTableType m_impl
+144 <  8>           WTF::HashTable<unsigned int, WTF::KeyValuePair<unsigned int, WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> > >, WTF::KeyValuePairKeyExtractor<WTF::KeyValuePair<unsigned int, WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> > > >, WTF::DefaultHash<unsigned int>, WTF::HashMap<unsigned int, WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> >, WTF::DefaultHash<unsigned int>, WTF::HashTraits<unsigned int>, WTF::HashTraits<WTF::RefPtr<WebCore::GlyphPage, WTF::RawPtrTraits<WebCore::GlyphPage>, WTF::DefaultRefDerefTraits<WebCore::GlyphPage> > >, WTF::HashTableTraits>::KeyValuePairTraits, WTF::HashTraits<unsigned int> >::(anonymous union) None
+152 <  8>     std::__1::unique_ptr<WebCore::GlyphMetricsMap<WebCore::FloatRect>, std::__1::default_delete<WebCore::GlyphMetricsMap<WebCore::FloatRect> > > m_glyphToBoundsMap
+152 <  8>         std::__1::__compressed_pair<WebCore::GlyphMetricsMap<WebCore::FloatRect> *, std::__1::default_delete<WebCore::GlyphMetricsMap<WebCore::FloatRect> > > __ptr_
+152 <  8>             std::__1::__compressed_pair_elem<WebCore::GlyphMetricsMap<WebCore::FloatRect> *, 0, false> std::__1::__compressed_pair_elem<WebCore::GlyphMetricsMap<WebCore::FloatRect> *, 0, false>
+152 <  8>               WebCore::GlyphMetricsMap<WebCore::FloatRect> * __value_
+152 <  1>             std::__1::__compressed_pair_elem<std::__1::default_delete<WebCore::GlyphMetricsMap<WebCore::FloatRect> >, 1, true> std::__1::__compressed_pair_elem<std::__1::default_delete<WebCore::GlyphMetricsMap<WebCore::FloatRect> >, 1, true>
+152 <  1>                 std::__1::default_delete<WebCore::GlyphMetricsMap<WebCore::FloatRect> > std::__1::default_delete<WebCore::GlyphMetricsMap<WebCore::FloatRect> >
+160 < 80>     WebCore::GlyphMetricsMap<float> m_glyphToWidthMap
+160 <  1>       bool m_filledPrimaryPage
+161 <  3>       <PADDING: 3 bytes>
+164 < 64>         WebCore::GlyphMetricsMap<float>::GlyphMetricsPage m_primaryPage
+164 < 64>             std::__1::array<float, 16> m_metrics
+164 < 64>               float[16] __elems_
+228 <  4>       <PADDING: 4 bytes>
+232 <  8>         WTF::HashMap<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> >, WTF::DefaultHash<int>, WTF::HashTraits<int>, WTF::HashTraits<std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> > >, WTF::HashTableTraits> m_pages
+232 <  8>             WTF::HashMap<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> >, WTF::DefaultHash<int>, WTF::HashTraits<int>, WTF::HashTraits<std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> > >, WTF::HashTableTraits>::HashTableType m_impl
+232 <  8>               WTF::HashTable<int, WTF::KeyValuePair<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> > >, WTF::KeyValuePairKeyExtractor<WTF::KeyValuePair<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> > > >, WTF::DefaultHash<int>, WTF::HashMap<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> >, WTF::DefaultHash<int>, WTF::HashTraits<int>, WTF::HashTraits<std::__1::unique_ptr<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<float>::GlyphMetricsPage> > >, WTF::HashTableTraits>::KeyValuePairTraits, WTF::HashTraits<int> >::(anonymous union) None
+240 <912>     WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> > m_glyphPathMap
+240 <  1>       bool m_filledPrimaryPage
+241 <  7>       <PADDING: 7 bytes>
+248 <896>         WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage m_primaryPage
+248 <896>             std::__1::array<std::__1::optional<WebCore::Path>, 16> m_metrics
+248 <896>               std::__1::optional<WebCore::Path>[16] __elems_
+1144 <  8>         WTF::HashMap<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> >, WTF::DefaultHash<int>, WTF::HashTraits<int>, WTF::HashTraits<std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> > >, WTF::HashTableTraits> m_pages
+1144 <  8>             WTF::HashMap<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> >, WTF::DefaultHash<int>, WTF::HashTraits<int>, WTF::HashTraits<std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> > >, WTF::HashTableTraits>::HashTableType m_impl
+1144 <  8>               WTF::HashTable<int, WTF::KeyValuePair<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> > >, WTF::KeyValuePairKeyExtractor<WTF::KeyValuePair<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> > > >, WTF::DefaultHash<int>, WTF::HashMap<int, std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> >, WTF::DefaultHash<int>, WTF::HashTraits<int>, WTF::HashTraits<std::__1::unique_ptr<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage, std::__1::default_delete<WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage> > >, WTF::HashTableTraits>::KeyValuePairTraits, WTF::HashTraits<int> >::(anonymous union) None
+1152 <  8>     WTF::BitVector m_codePointSupport
+1152 <  8>       uintptr_t m_bitsOrPointer
+1160 <  8>     WTF::RefPtr<WebCore::OpenTypeMathData, WTF::RawPtrTraits<WebCore::OpenTypeMathData>, WTF::DefaultRefDerefTraits<WebCore::OpenTypeMathData> > m_mathData
+1160 <  8>       WTF::RawPtrTraits<WebCore::OpenTypeMathData>::StorageType m_ptr
+1168 < 16>     std::__1::optional<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType> > m_renderingResourceIdentifier
+1168 < 16>         std::__1::__optional_move_assign_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true> std::__1::__optional_move_assign_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true>
+1168 < 16>             std::__1::__optional_copy_assign_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true> std::__1::__optional_copy_assign_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true>
+1168 < 16>                 std::__1::__optional_move_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true> std::__1::__optional_move_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true>
+1168 < 16>                     std::__1::__optional_copy_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true> std::__1::__optional_copy_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true>
+1168 < 16>                         std::__1::__optional_storage_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, false> std::__1::__optional_storage_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, false>
+1168 < 16>                             std::__1::__optional_destruct_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true> std::__1::__optional_destruct_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true>
+1168 <  8>                               std::__1::__optional_destruct_base<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType>, true>::(anonymous union) None
+1176 <  1>                               bool __engaged_
+1168 <  1>         std::__1::__optional_sfinae_ctor_base_t<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType> > std::__1::__optional_sfinae_ctor_base_t<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType> >
+1168 <  1>         std::__1::__optional_sfinae_assign_base_t<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType> > std::__1::__optional_sfinae_assign_base_t<WTF::ObjectIdentifier<WebCore::RenderingResourceIdentifierType> >
+1177 <  7>   <PADDING: 7 bytes>
+1184 <  8>     std::__1::unique_ptr<WebCore::Font::DerivedFonts, std::__1::default_delete<WebCore::Font::DerivedFonts> > m_derivedFontData
+1184 <  8>         std::__1::__compressed_pair<WebCore::Font::DerivedFonts *, std::__1::default_delete<WebCore::Font::DerivedFonts> > __ptr_
+1184 <  8>             std::__1::__compressed_pair_elem<WebCore::Font::DerivedFonts *, 0, false> std::__1::__compressed_pair_elem<WebCore::Font::DerivedFonts *, 0, false>
+1184 <  8>               WebCore::Font::DerivedFonts * __value_
+1184 <  1>             std::__1::__compressed_pair_elem<std::__1::default_delete<WebCore::Font::DerivedFonts>, 1, true> std::__1::__compressed_pair_elem<std::__1::default_delete<WebCore::Font::DerivedFonts>, 1, true>
+1184 <  1>                 std::__1::default_delete<WebCore::Font::DerivedFonts> std::__1::default_delete<WebCore::Font::DerivedFonts>
+1192 <  4>   WebCore::Font::SupportsFeature m_supportsSmallCaps
+1196 <  4>   WebCore::Font::SupportsFeature m_supportsAllSmallCaps
+1200 <  4>   WebCore::Font::SupportsFeature m_supportsPetiteCaps
+1204 <  4>   WebCore::Font::SupportsFeature m_supportsAllPetiteCaps
+1208 < 16>     std::__1::optional<PAL::OTSVGTable> m_otSVGTable
+1208 < 16>         std::__1::__optional_move_assign_base<PAL::OTSVGTable, false> std::__1::__optional_move_assign_base<PAL::OTSVGTable, false>
+1208 < 16>             std::__1::__optional_copy_assign_base<PAL::OTSVGTable, false> std::__1::__optional_copy_assign_base<PAL::OTSVGTable, false>
+1208 < 16>                 std::__1::__optional_move_base<PAL::OTSVGTable, false> std::__1::__optional_move_base<PAL::OTSVGTable, false>
+1208 < 16>                     std::__1::__optional_copy_base<PAL::OTSVGTable, false> std::__1::__optional_copy_base<PAL::OTSVGTable, false>
+1208 < 16>                         std::__1::__optional_storage_base<PAL::OTSVGTable, false> std::__1::__optional_storage_base<PAL::OTSVGTable, false>
+1208 < 16>                             std::__1::__optional_destruct_base<PAL::OTSVGTable, false> std::__1::__optional_destruct_base<PAL::OTSVGTable, false>
+1208 <  8>                               std::__1::__optional_destruct_base<PAL::OTSVGTable, false>::(anonymous union) None
+1216 <  1>                               bool __engaged_
+1208 <  1>         std::__1::__optional_sfinae_ctor_base_t<PAL::OTSVGTable> std::__1::__optional_sfinae_ctor_base_t<PAL::OTSVGTable>
+1208 <  1>         std::__1::__optional_sfinae_assign_base_t<PAL::OTSVGTable> std::__1::__optional_sfinae_assign_base_t<PAL::OTSVGTable>
+1217 <  7>   <PADDING: 7 bytes>
+1224 < 24>     std::__1::optional<WebCore::Font::ComplexColorFormatGlyphs> m_glyphsWithComplexColorFormat
+1224 < 24>         std::__1::__optional_move_assign_base<WebCore::Font::ComplexColorFormatGlyphs, false> std::__1::__optional_move_assign_base<WebCore::Font::ComplexColorFormatGlyphs, false>
+1224 < 24>             std::__1::__optional_copy_assign_base<WebCore::Font::ComplexColorFormatGlyphs, false> std::__1::__optional_copy_assign_base<WebCore::Font::ComplexColorFormatGlyphs, false>
+1224 < 24>                 std::__1::__optional_move_base<WebCore::Font::ComplexColorFormatGlyphs, false> std::__1::__optional_move_base<WebCore::Font::ComplexColorFormatGlyphs, false>
+1224 < 24>                     std::__1::__optional_copy_base<WebCore::Font::ComplexColorFormatGlyphs, false> std::__1::__optional_copy_base<WebCore::Font::ComplexColorFormatGlyphs, false>
+1224 < 24>                         std::__1::__optional_storage_base<WebCore::Font::ComplexColorFormatGlyphs, false> std::__1::__optional_storage_base<WebCore::Font::ComplexColorFormatGlyphs, false>
+1224 < 24>                             std::__1::__optional_destruct_base<WebCore::Font::ComplexColorFormatGlyphs, false> std::__1::__optional_destruct_base<WebCore::Font::ComplexColorFormatGlyphs, false>
+1224 < 16>                               std::__1::__optional_destruct_base<WebCore::Font::ComplexColorFormatGlyphs, false>::(anonymous union) None
+1240 <  1>                               bool __engaged_
+1224 <  1>         std::__1::__optional_sfinae_ctor_base_t<WebCore::Font::ComplexColorFormatGlyphs> std::__1::__optional_sfinae_ctor_base_t<WebCore::Font::ComplexColorFormatGlyphs>
+1224 <  1>         std::__1::__optional_sfinae_assign_base_t<WebCore::Font::ComplexColorFormatGlyphs> std::__1::__optional_sfinae_assign_base_t<WebCore::Font::ComplexColorFormatGlyphs>
+1241 <  7>   <PADDING: 7 bytes>
+1248 <  2>   WebCore::Glyph m_spaceGlyph
+1250 <  2>   WebCore::Glyph m_zeroWidthSpaceGlyph
+1252 <  1>   WebCore::Font::Origin m_origin
+1253 <  1>   WebCore::Font::Visibility m_visibility
+1254 <  2>   <PADDING: 2 bytes>
+1256 <  4>   float m_spaceWidth
+1260 <  4>   float m_syntheticBoldOffset
+1264 < :1>   unsigned int m_treatAsFixedPitch : 1
+1264 < :1>   unsigned int m_isInterstitial : 1
+1264 < :1>   unsigned int m_isTextOrientationFallback : 1
+1264 < :1>   unsigned int m_isBrokenIdeographFallback : 1
+1264 < :1>   unsigned int m_hasVerticalGlyphs : 1
+1264 < :1>   unsigned int m_isUsedInSystemFallbackFontCache : 1
+1264 < :1>   unsigned int m_allowsAntialiasing : 1
+1264 < :1>   <UNUSED BITS: 1 bit>
+1265 <  7>   <PADDING: 7 bytes>
Total byte size: 1272
Total pad bytes: 57
Padding percentage: 4.48 %
OpenSource %
Comment 1 Radar WebKit Bug Importer 2023-02-05 21:56:50 PST 
<rdar://problem/105068653>
Comment 2 Simon Fraser (smfr) 2023-02-05 21:59:18 PST 
Created attachment 464861 [details]
Patch
Comment 3 Darin Adler 2023-02-05 22:13:20 PST 
Comment on attachment 464861 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=464861&action=review

> COMMIT_MESSAGE:9
> +Reduces size from 1272 to 1256 bytes.

That is a lot of bytes! The padding was not a significant fraction. I wonder what the big users are and if this really needs to be over 1000 bytes.
Comment 4 Simon Fraser (smfr) 2023-02-06 08:29:46 PST 
(In reply to Darin Adler from comment #3)
> Comment on attachment 464861 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=464861&action=review
> 
> > COMMIT_MESSAGE:9
> > +Reduces size from 1272 to 1256 bytes.
> 
> That is a lot of bytes! The padding was not a significant fraction. I wonder
> what the big users are and if this really needs to be over 1000 bytes.

The large members (see the second column):

 +80 < 56>     const WebCore::FontPlatformData m_platformData
+164 < 64>         WebCore::GlyphMetricsMap<float>::GlyphMetricsPage m_primaryPage
+248 <896>         WebCore::GlyphMetricsMap<std::__1::optional<WebCore::Path> >::GlyphMetricsPage m_primaryPage

That last one could be heap allocated?
Comment 5 Darin Adler 2023-02-06 09:01:53 PST 
I guess heap allocated might not be an improvement.
Comment 6 Darin Adler 2023-02-06 09:02:14 PST 
Unless it’s often missing, in which case it would indeed be an improvement!
Comment 7 EWS 2023-02-06 09:17:37 PST 
Committed 259896@main (c62b38e4e53b): <https://commits.webkit.org/259896@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 464861 [details].