Changeset 216512 in webkit

Timestamp:

May 9, 2017, 10:11:27 AM (8 years ago)

Author:

mark.lam@apple.com

Message:

Force StaticStringImpl constructor to use the constexpr versions of StringImplShape constructors.
​https://bugs.webkit.org/show_bug.cgi?id=171861

Reviewed by Yusuke Suzuki.

This is strictly necessary for correctness of the StaticStringImpl implementation.
We force the constructor selection by adding an extra dummy argument to the
constexpr versions of the StringImplShape constructors to disambiguate them from
the non-constexpr versions.

• wtf/text/StringImpl.h:

(WTF::StringImplShape::StringImplShape):
(WTF::StringImpl::StaticStringImpl::StaticStringImpl):

Location:

trunk/Source/WTF

Files:

• ChangeLog (modified) (1 diff)
• wtf/text/StringImpl.h (modified) (4 diffs)

trunk/Source/WTF/ChangeLog

@@ +1 @@
+2017-05-09  Mark Lam  <mark.lam@apple.com>
+
+        Force StaticStringImpl constructor to use the constexpr versions of StringImplShape constructors.
+        https://bugs.webkit.org/show_bug.cgi?id=171861
+
+        Reviewed by Yusuke Suzuki.
+
+        This is strictly necessary for correctness of the StaticStringImpl implementation.
+        We force the constructor selection by adding an extra dummy argument to the
+        constexpr versions of the StringImplShape constructors to disambiguate them from
+        the non-constexpr versions.
+
+        * wtf/text/StringImpl.h:
+        (WTF::StringImplShape::StringImplShape):
+        (WTF::StringImpl::StaticStringImpl::StaticStringImpl):
+
 2017-05-09  Zan Dobersek  <zdobersek@igalia.com>
 

trunk/Source/WTF/wtf/text/StringImpl.h

@@ -147 +147 @@
     { }
 
+    enum ConstructWithConstExprTag { ConstructWithConstExpr };
+    
     template<unsigned charactersCount>
-    constexpr StringImplShape(unsigned refCount, unsigned length, const char (&characters)[charactersCount], unsigned hashAndFlags)
+    constexpr StringImplShape(unsigned refCount, unsigned length, const char (&characters)[charactersCount], unsigned hashAndFlags, ConstructWithConstExprTag)
         : m_refCount(refCount)
         , m_length(length)
@@ -156 +158 @@
     
     template<unsigned charactersCount>
-    constexpr StringImplShape(unsigned refCount, unsigned length, const char16_t (&characters)[charactersCount], unsigned hashAndFlags)
+    constexpr StringImplShape(unsigned refCount, unsigned length, const char16_t (&characters)[charactersCount], unsigned hashAndFlags, ConstructWithConstExprTag)
         : m_refCount(refCount)
         , m_length(length)
@@ -594 +596 @@
         constexpr StaticStringImpl(const char (&characters)[charactersCount], StringKind stringKind = StringNormal)
             : StringImplShape(s_refCountFlagIsStaticString, charactersCount - 1, characters,
-                s_hashFlag8BitBuffer | s_hashFlagDidReportCost | stringKind | BufferInternal | (StringHasher::computeLiteralHashAndMaskTop8Bits(characters) << s_flagCount))
+                s_hashFlag8BitBuffer | s_hashFlagDidReportCost | stringKind | BufferInternal | (StringHasher::computeLiteralHashAndMaskTop8Bits(characters) << s_flagCount), ConstructWithConstExpr)
         {
         }
@@ -601 +603 @@
         constexpr StaticStringImpl(const char16_t (&characters)[charactersCount], StringKind stringKind = StringNormal)
             : StringImplShape(s_refCountFlagIsStaticString, charactersCount - 1, characters,
-                s_hashFlagDidReportCost | stringKind | BufferInternal | (StringHasher::computeLiteralHashAndMaskTop8Bits(characters) << s_flagCount))
+                s_hashFlagDidReportCost | stringKind | BufferInternal | (StringHasher::computeLiteralHashAndMaskTop8Bits(characters) << s_flagCount), ConstructWithConstExpr)
         {
         }