Changeset 279689 in webkit

Timestamp:

Jul 7, 2021 5:53:54 PM (3 years ago)

Author:

mark.lam@apple.com

Message:

Heap::waitForCollector() needs to set m_mutatorDidRun.
​https://bugs.webkit.org/show_bug.cgi?id=227782
rdar://78326474

Reviewed by Saam Barati.

Heap::waitForCollector() is one of 2 clients of Heap::stopIfNecessarySlow(unsigned oldState).
The other client, Heap::stopIfNecessarySlow() sets m_mutatorDidRun to true after
calling Heap::stopIfNecessarySlow(unsigned oldState). Heap::waitForCollector()
needs to do the same. Constraint solvers rely on this.

Without this, one fall out we've seen is that DOMGCOutputConstraint fails to
visitOutputConstraints, and as a result, opaqueRoots may not get updated. This
issue was caught by the GC verifier.

• heap/Heap.cpp:

(JSC::Heap::waitForCollector):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• heap/Heap.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2021-07-07  Mark Lam  <mark.lam@apple.com>
+
+        Heap::waitForCollector() needs to set m_mutatorDidRun.
+        https://bugs.webkit.org/show_bug.cgi?id=227782
+        rdar://78326474
+
+        Reviewed by Saam Barati.
+
+        Heap::waitForCollector() is one of 2 clients of Heap::stopIfNecessarySlow(unsigned oldState).
+        The other client, Heap::stopIfNecessarySlow() sets m_mutatorDidRun to true after
+        calling Heap::stopIfNecessarySlow(unsigned oldState).  Heap::waitForCollector()
+        needs to do the same.  Constraint solvers rely on this.
+
+        Without this, one fall out we've seen is that DOMGCOutputConstraint fails to
+        visitOutputConstraints, and as a result, opaqueRoots may not get updated.  This
+        issue was caught by the GC verifier.
+
+        * heap/Heap.cpp:
+        (JSC::Heap::waitForCollector):
+
 2021-07-07  Michael Saboff  <msaboff@apple.com>
 

trunk/Source/JavaScriptCore/heap/Heap.cpp

@@ -1883 +1883 @@
             continue;
         
+        m_mutatorDidRun = true;
         // FIXME: We wouldn't need this if stopIfNecessarySlow() had a mode where it knew to just
         // do the collection.
         relinquishConn();
-        
+
         if (done) {
             clearMutatorWaiting(); // Clean up just in case.