Changeset 247900 in webkit for trunk/Source/JavaScriptCore/heap/HeapCell.h

Timestamp:

Jul 28, 2019, 9:31:04 PM (6 years ago)

Author:

[email protected]

Message:

Unreviewed, rolling out r247886.
​https://bugs.webkit.org/show_bug.cgi?id=200214

"Causes PLT5 regression on some machines" (Requested by mlam|a
on #webkit).

Reverted changeset:

"Add crash diagnostics for debugging unexpected zapped cells."
​https://bugs.webkit.org/show_bug.cgi?id=200149
​https://trac.webkit.org/changeset/247886

File:

• trunk/Source/JavaScriptCore/heap/HeapCell.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/heap/HeapCell.h

@@ -1 +1 @@
 /*
- * Copyright (C) 2016-2019 Apple Inc. All rights reserved.
+ * Copyright (C) 2016-2018 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48 +48 @@
     HeapCell() { }
     
-    // We're intentionally only zapping the bits for the structureID and leaving
-    // the rest of the cell header bits intact for crash analysis uses.
-    enum ZapReason : int8_t { Unspecified, Destruction, StopAllocating };
-    void zap(ZapReason reason)
-    {
-        uint32_t* cellWords = bitwise_cast<uint32_t*>(this);
-        cellWords[0] = 0;
-        // Leaving cellWords[1] alone for crash analysis if needed.
-        cellWords[2] = reason;
-    }
-    bool isZapped() const { return !*bitwise_cast<const uint32_t*>(this); }
+    void zap() { *reinterpret_cast_ptr<uintptr_t**>(this) = 0; }
+    bool isZapped() const { return !*reinterpret_cast_ptr<uintptr_t* const*>(this); }
 
     bool isLive();