Changeset 189596 in webkit for trunk/Source/JavaScriptCore/runtime/Structure.cpp

Timestamp:

Sep 10, 2015, 4:07:08 PM (10 years ago)

Author:

[email protected]

Message:

Structure should be able to tell you if it had ever been a dictionary
​https://bugs.webkit.org/show_bug.cgi?id=149047

Reviewed by Mark Lam.

Introduces the hasBeenDictionary flag to Structure, which tells you if this structure or
any of its ancestors is a dictionary. We already implicitly tracked this for DFG
watchpoint optimizations, so this is mainly just decoupling that existing logic from
watchpoints. Having Structure::hasBeenDictionary() enables some of the heuristics in the
property type inference work (​https://bugs.webkit.org/show_bug.cgi?id=148610).

• runtime/Structure.cpp:

(JSC::Structure::Structure):
(JSC::Structure::toDictionaryTransition):
(JSC::Structure::dump):

• runtime/Structure.h:

File:

• trunk/Source/JavaScriptCore/runtime/Structure.cpp (modified) (6 diffs)

trunk/Source/JavaScriptCore/runtime/Structure.cpp

@@ -209 +209 @@
     setHasRareData(false);
     setTransitionWatchpointIsLikelyToBeFired(false);
+    setHasBeenDictionary(false);
  
     ASSERT(inlineCapacity <= JSFinalObject::maxInlineCapacity());
@@ -240 +241 @@
     setHasRareData(false);
     setTransitionWatchpointIsLikelyToBeFired(false);
+    setHasBeenDictionary(false);
  
     TypeInfo typeInfo = TypeInfo(CellType, StructureFlags);
@@ -269 +271 @@
     setStaticFunctionsReified(previous->staticFunctionsReified());
     setHasRareData(false);
+    setHasBeenDictionary(previous->hasBeenDictionary());
  
     TypeInfo typeInfo = previous->typeInfo();
@@ -538 +541 @@
     transition->setDictionaryKind(kind);
     transition->pin();
-    transition->setTransitionWatchpointIsLikelyToBeFired(true);
+    transition->setHasBeenDictionary(true);
 
     transition->checkOffsetConsistency();
@@ -1157 +1160 @@
     switch (dictionaryKind()) {
     case NoneDictionaryKind:
+        if (hasBeenDictionary())
+            out.print(", Has been dictionary");
         break;
     case CachedDictionaryKind:
@@ -1165 +1170 @@
         break;
     }
+
+    if (transitionWatchpointSetIsStillValid())
+        out.print(", Leaf");
+    else if (transitionWatchpointIsLikelyToBeFired())
+        out.print(", Shady leaf");
     
     out.print("]");