Changeset 146568 in webkit

Timestamp:

Mar 22, 2013 12:36:58 AM (11 years ago)

Author:

rniwa@webkit.org

Message:

Leak bots erroneously report JSC::WatchpointSet as leaking
​https://bugs.webkit.org/show_bug.cgi?id=107781

Reviewed by Filip Pizlo.

Since leaks doesn't support tagged pointers, avoid using it by flipping the bit flag to indicate
the entry is "fat". We set the flag when the entry is NOT fat; i.e. slim.

Replaced FatFlag by SlimFlag and initialized m_bits with this flag to indicate that the entry is
initially "slim".

• runtime/SymbolTable.cpp:

(JSC::SymbolTableEntry::copySlow): Don't set FatFlag since it has been replaced by SlimFlag.
(JSC::SymbolTableEntry::inflateSlow): Ditto.

• runtime/SymbolTable.h:

(JSC::SymbolTableEntry::Fast::Fast): Set SlimFlag by default.
(JSC::SymbolTableEntry::Fast::isNull): Ignore SlimFlag.
(JSC::SymbolTableEntry::Fast::isFat): An entry is fat when m_bits is not entirely zero and SlimFlag
is not set.

(JSC::SymbolTableEntry::SymbolTableEntry): Set SlimFlag by default.
(JSC::SymbolTableEntry::SymbolTableEntry::getFast): Set SlimFlag when creating Fast from a fat entry.
(JSC::SymbolTableEntry::isNull): Ignore SlimFlag.
(JSC::SymbolTableEntry::FatEntry::FatEntry): Strip SlimFlag.
(JSC::SymbolTableEntry::isFat): An entry is fat when m_bits is not entirely zero and SlimFlag is unset.
(JSC::SymbolTableEntry::fatEntry): Don't strip FatFlag as this flag doesn't exist anymore.
(JSC::SymbolTableEntry::pack): Preserve SlimFlag.

(JSC::SymbolTableIndexHashTraits): empty value is no longer zero so don't set emptyValueIsZero true.

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• runtime/SymbolTable.cpp (modified) (2 diffs)
• runtime/SymbolTable.h (modified) (15 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2013-03-22  Ryosuke Niwa  <rniwa@webkit.org>
+
+        Leak bots erroneously report JSC::WatchpointSet as leaking
+        https://bugs.webkit.org/show_bug.cgi?id=107781
+
+        Reviewed by Filip Pizlo.
+
+        Since leaks doesn't support tagged pointers, avoid using it by flipping the bit flag to indicate
+        the entry is "fat". We set the flag when the entry is NOT fat; i.e. slim.
+
+        Replaced FatFlag by SlimFlag and initialized m_bits with this flag to indicate that the entry is
+        initially "slim".
+
+        * runtime/SymbolTable.cpp:
+        (JSC::SymbolTableEntry::copySlow): Don't set FatFlag since it has been replaced by SlimFlag.
+        (JSC::SymbolTableEntry::inflateSlow): Ditto.
+
+        * runtime/SymbolTable.h:
+        (JSC::SymbolTableEntry::Fast::Fast): Set SlimFlag by default.
+        (JSC::SymbolTableEntry::Fast::isNull): Ignore SlimFlag.
+        (JSC::SymbolTableEntry::Fast::isFat): An entry is fat when m_bits is not entirely zero and SlimFlag
+        is not set.
+
+        (JSC::SymbolTableEntry::SymbolTableEntry): Set SlimFlag by default.
+        (JSC::SymbolTableEntry::SymbolTableEntry::getFast): Set SlimFlag when creating Fast from a fat entry.
+        (JSC::SymbolTableEntry::isNull): Ignore SlimFlag.
+        (JSC::SymbolTableEntry::FatEntry::FatEntry): Strip SlimFlag.
+        (JSC::SymbolTableEntry::isFat): An entry is fat when m_bits is not entirely zero and SlimFlag is unset.
+        (JSC::SymbolTableEntry::fatEntry): Don't strip FatFlag as this flag doesn't exist anymore.
+        (JSC::SymbolTableEntry::pack): Preserve SlimFlag.
+
+        (JSC::SymbolTableIndexHashTraits): empty value is no longer zero so don't set emptyValueIsZero true.
+
 2013-03-21  Mark Hahnenberg  <mhahnenberg@apple.com>
 

trunk/Source/JavaScriptCore/runtime/SymbolTable.cpp

@@ -39 +39 @@
     FatEntry* newFatEntry = new FatEntry(*other.fatEntry());
     freeFatEntry();
-    m_bits = bitwise_cast<intptr_t>(newFatEntry) | FatFlag;
+    m_bits = bitwise_cast<intptr_t>(newFatEntry);
     return *this;
 }
@@ -95 +95 @@
 {
     FatEntry* entry = new FatEntry(m_bits);
-    m_bits = bitwise_cast<intptr_t>(entry) | FatFlag;
+    m_bits = bitwise_cast<intptr_t>(entry);
     return entry;
 }

trunk/Source/JavaScriptCore/runtime/SymbolTable.h

@@ -94 +94 @@
         public:
             Fast()
-                : m_bits(0)
+                : m_bits(SlimFlag)
             {
             }
@@ -105 +105 @@
             bool isNull() const
             {
-                return !m_bits;
+                return !(m_bits & ~SlimFlag);
             }
 
@@ -130 +130 @@
             bool isFat() const
             {
-                return m_bits & FatFlag;
+                return !(m_bits & SlimFlag);
             }
             
@@ -139 +139 @@
 
         SymbolTableEntry()
-            : m_bits(0)
+            : m_bits(SlimFlag)
         {
         }
 
         SymbolTableEntry(int index)
-            : m_bits(0)
+            : m_bits(SlimFlag)
         {
             ASSERT(isValidIndex(index));
@@ -151 +151 @@
 
         SymbolTableEntry(int index, unsigned attributes)
-            : m_bits(0)
+            : m_bits(SlimFlag)
         {
             ASSERT(isValidIndex(index));
@@ -163 +163 @@
         
         SymbolTableEntry(const SymbolTableEntry& other)
-            : m_bits(0)
+            : m_bits(SlimFlag)
         {
             *this = other;
@@ -179 +179 @@
         bool isNull() const
         {
-            return !bits();
+            return !(bits() & ~SlimFlag);
         }
 
@@ -197 +197 @@
             wasFat = isFat();
             if (wasFat)
-                result.m_bits = fatEntry()->m_bits;
+                result.m_bits = fatEntry()->m_bits | SlimFlag;
             else
                 result.m_bits = m_bits;
@@ -247 +247 @@
         
     private:
-        static const intptr_t FatFlag = 0x1;
+        static const intptr_t SlimFlag = 0x1;
         static const intptr_t ReadOnlyFlag = 0x2;
         static const intptr_t DontEnumFlag = 0x4;
@@ -257 +257 @@
         public:
             FatEntry(intptr_t bits)
-                : m_bits(bits | FatFlag)
+                : m_bits(bits & ~SlimFlag)
             {
             }
@@ -271 +271 @@
         bool isFat() const
         {
-            return m_bits & FatFlag;
+            return !(m_bits & SlimFlag);
         }
         
@@ -277 +277 @@
         {
             ASSERT(isFat());
-            return bitwise_cast<const FatEntry*>(m_bits & ~FatFlag);
+            return bitwise_cast<const FatEntry*>(m_bits);
         }
         
@@ -283 +283 @@
         {
             ASSERT(isFat());
-            return bitwise_cast<FatEntry*>(m_bits & ~FatFlag);
+            return bitwise_cast<FatEntry*>(m_bits);
         }
         
@@ -320 +320 @@
         void pack(int index, bool readOnly, bool dontEnum)
         {
+            ASSERT(!isFat());
             intptr_t& bitsRef = bits();
-            bitsRef = (static_cast<intptr_t>(index) << FlagBits) | NotNullFlag;
+            bitsRef = (static_cast<intptr_t>(index) << FlagBits) | NotNullFlag | SlimFlag;
             if (readOnly)
                 bitsRef |= ReadOnlyFlag;
@@ -337 +338 @@
 
     struct SymbolTableIndexHashTraits : HashTraits<SymbolTableEntry> {
-        static const bool emptyValueIsZero = true;
         static const bool needsDestruction = true;
     };