Changeset 185099 in webkit for trunk/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp

Timestamp:

Jun 1, 2015, 7:59:39 PM (10 years ago)

Author:

[email protected]

Message:

If a call has ever taken the virtual slow path, make sure that the DFG knows this
​https://bugs.webkit.org/show_bug.cgi?id=145501

Reviewed by Geoffrey Garen.

Now now return higher fidelity information in the case of no polymorphic call stub. If the
virtual slow path was ever taken, we note this, and we note either zero or one call variant
based on the IC's last callee.

• bytecode/CallLinkStatus.cpp:

(JSC::CallLinkStatus::computeFromCallLinkInfo):
(JSC::CallLinkStatus::computeFor):

File:

• trunk/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp

@@ -151 +151 @@
     // is probably OK for now.
     
+    // FIXME: If the GC often clears this call, we should probably treat it like it always takes the
+    // slow path. We could be smart about this; for example if we cleared a specific callee but the
+    // despecified executable was alive then we could note that separately.
+    // https://bugs.webkit.org/show_bug.cgi?id=145502
+    
     // PolymorphicCallStubRoutine is a GCAwareJITStubRoutine, so if non-null, it will stay alive
     // until next GC even if the CallLinkInfo is concurrently cleared. Also, the variants list is
@@ -210 +215 @@
     }
     
-    if (callLinkInfo.slowPathCount >= Options::couldTakeSlowCaseMinimumCount())
-        return takesSlowPath();
-    
-    JSFunction* target = callLinkInfo.lastSeenCallee.get();
-    if (!target)
-        return takesSlowPath();
-    
-    if (callLinkInfo.hasSeenClosure)
-        return CallLinkStatus(target->executable());
-
-    return CallLinkStatus(target);
+    CallLinkStatus result;
+    
+    if (JSFunction* target = callLinkInfo.lastSeenCallee.get()) {
+        CallVariant variant(target);
+        if (callLinkInfo.hasSeenClosure)
+            variant = variant.despecifiedClosure();
+        result.m_variants.append(variant);
+    }
+    
+    result.m_couldTakeSlowPath = !!callLinkInfo.slowPathCount;
+
+    return result;
 }