Title: [175172] trunk/Source/_javascript_Core
- Revision
- 175172
- Author
- [email protected]
- Date
- 2014-10-24 12:16:29 -0700 (Fri, 24 Oct 2014)
Log Message
Simplified IndexingType's hasAnyArrayStorage().
<https://webkit.org/b/138051>
Reviewed by Michael Saboff.
IndexingType's hasAnyArrayStorage() currently does subtraction of ArrayStorageShape
with the purpose of making non-ArrayStorage types underflow (with that subtraction)
and have a result that exceeds SlowPutArrayStorageShape. What it is doing is
basically checking for a shape value that is greater equal to ArrayStorageShape.
We can just simplify the code as such.
Also added a comment to describe the structure of the bits in IndexingType.
* runtime/IndexingType.h:
(JSC::hasAnyArrayStorage):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (175171 => 175172)
--- trunk/Source/_javascript_Core/ChangeLog 2014-10-24 19:13:15 UTC (rev 175171)
+++ trunk/Source/_javascript_Core/ChangeLog 2014-10-24 19:16:29 UTC (rev 175172)
@@ -1,3 +1,21 @@
+2014-10-24 Mark Lam <[email protected]>
+
+ Simplified IndexingType's hasAnyArrayStorage().
+ <https://webkit.org/b/138051>
+
+ Reviewed by Michael Saboff.
+
+ IndexingType's hasAnyArrayStorage() currently does subtraction of ArrayStorageShape
+ with the purpose of making non-ArrayStorage types underflow (with that subtraction)
+ and have a result that exceeds SlowPutArrayStorageShape. What it is doing is
+ basically checking for a shape value that is greater equal to ArrayStorageShape.
+ We can just simplify the code as such.
+
+ Also added a comment to describe the structure of the bits in IndexingType.
+
+ * runtime/IndexingType.h:
+ (JSC::hasAnyArrayStorage):
+
2014-10-23 Joseph Pecoraro <[email protected]>
Web Inspector: Provide a way to have alternate inspector agents
Modified: trunk/Source/_javascript_Core/runtime/IndexingType.h (175171 => 175172)
--- trunk/Source/_javascript_Core/runtime/IndexingType.h 2014-10-24 19:13:15 UTC (rev 175171)
+++ trunk/Source/_javascript_Core/runtime/IndexingType.h 2014-10-24 19:16:29 UTC (rev 175172)
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2012, 2014 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -31,6 +31,22 @@
namespace JSC {
+/*
+ Structure of the IndexingType
+ =============================
+ Conceptually, the IndexingType looks like this:
+
+ struct IndexingType {
+ uint8_t isArray:1; // bit 0
+ uint8_t shape:4; // bit 1 - 4
+ uint8_t mayHaveIndexedAccessors:1; // bit 5
+ };
+
+ The shape values (e.g. Int32Shape, ContiguousShape, etc) are an enumeration of
+ various shapes (though not necessarily sequential in terms of their values).
+ Hence, shape values are not bitwise exclusive with respect to each other.
+*/
+
typedef uint8_t IndexingType;
// Flags for testing the presence of capabilities.
@@ -128,7 +144,7 @@
static inline bool hasAnyArrayStorage(IndexingType indexingType)
{
- return static_cast<uint8_t>((indexingType & IndexingShapeMask) - ArrayStorageShape) <= static_cast<uint8_t>(SlowPutArrayStorageShape - ArrayStorageShape);
+ return static_cast<uint8_t>(indexingType & IndexingShapeMask) >= ArrayStorageShape;
}
static inline bool shouldUseSlowPut(IndexingType indexingType)
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