Changeset 239013 in webkit

Timestamp:

Dec 8, 2018, 3:53:29 PM (6 years ago)

Author:

mark.lam@apple.com

Message:

Reduce size of PropertySlot and PutPropertySlot.
​https://bugs.webkit.org/show_bug.cgi?id=192526

Reviewed by Keith Miller.

With some minor adjustments, we can reduce the size of PropertySlot from 80 bytes
(19 padding bytes) to 64 bytes (3 padding bytes), and PutPropertySlot from 40
bytes (4 padding bytes) to 32 bytes (0 padding bytes but with 6 unused bits).
These measurements are for a 64-bit build.

• runtime/PropertySlot.h:
• runtime/PutPropertySlot.h:

(JSC::PutPropertySlot::PutPropertySlot):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• runtime/PropertySlot.h (modified) (3 diffs)
• runtime/PutPropertySlot.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2018-12-08  Mark Lam  <mark.lam@apple.com>
+
+        Reduce size of PropertySlot and PutPropertySlot.
+        https://bugs.webkit.org/show_bug.cgi?id=192526
+
+        Reviewed by Keith Miller.
+
+        With some minor adjustments, we can reduce the size of PropertySlot from 80 bytes
+        (19 padding bytes) to 64 bytes (3 padding bytes), and PutPropertySlot from 40
+        bytes (4 padding bytes) to 32 bytes (0 padding bytes but with 6 unused bits).
+        These measurements are for a 64-bit build.
+
+        * runtime/PropertySlot.h:
+        * runtime/PutPropertySlot.h:
+        (JSC::PutPropertySlot::PutPropertySlot):
+
 2018-12-08  Dominik Infuehr  <dinfuehr@igalia.com>
 

trunk/Source/JavaScriptCore/runtime/PropertySlot.h

@@ -371 +371 @@
     JS_EXPORT_PRIVATE JSValue customAccessorGetter(ExecState*, PropertyName) const;
 
-    unsigned m_attributes;
     union {
         EncodedJSValue value;
@@ -385 +384 @@
     } m_data;
 
+    unsigned m_attributes;
     PropertyOffset m_offset;
     JSValue m_thisValue;
@@ -393 +393 @@
     InternalMethodType m_internalMethodType;
     AdditionalDataType m_additionalDataType;
+    bool m_isTaintedByOpaqueObject;
     union {
         DOMAttributeAnnotation domAttribute;
         ModuleNamespaceSlot moduleNamespaceSlot;
     } m_additionalData;
-    bool m_isTaintedByOpaqueObject;
 };
 

trunk/Source/JavaScriptCore/runtime/PutPropertySlot.h

@@ -37 +37 @@
 class PutPropertySlot {
 public:
-    enum Type { Uncachable, ExistingProperty, NewProperty, SetterProperty, CustomValue, CustomAccessor };
+    enum Type : uint8_t { Uncachable, ExistingProperty, NewProperty, SetterProperty, CustomValue, CustomAccessor };
     enum Context { UnknownContext, PutById, PutByIdEval };
     typedef bool (*PutValueFunc)(ExecState*, EncodedJSValue thisObject, EncodedJSValue value);
 
     PutPropertySlot(JSValue thisValue, bool isStrictMode = false, Context context = UnknownContext, bool isInitialization = false)
-        : m_type(Uncachable)
-        , m_base(0)
+        : m_base(0)
         , m_thisValue(thisValue)
         , m_offset(invalidOffset)
         , m_isStrictMode(isStrictMode)
         , m_isInitialization(isInitialization)
+        , m_type(Uncachable)
         , m_context(context)
         , m_cacheability(CachingAllowed)
@@ -130 +130 @@
     bool isCacheable() const { return m_cacheability == CachingAllowed; }
 
-    Type m_type;
     JSObject* m_base;
     JSValue m_thisValue;
     PropertyOffset m_offset;
-    bool m_isStrictMode;
-    bool m_isInitialization;
+    bool m_isStrictMode : 1;
+    bool m_isInitialization : 1;
+    Type m_type;
     uint8_t m_context;
     CacheabilityType m_cacheability;