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):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@185099 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp b/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp
index bf4618b..ef02892 100644
--- a/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp
+++ b/Source/JavaScriptCore/bytecode/CallLinkStatus.cpp
@@ -150,6 +150,11 @@
// that is still marginally valid (i.e. the pointers ain't stale). This kind of raciness
// 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
// never mutated after the PolymorphicCallStubRoutine is instantiated. We have some conservative
@@ -209,17 +214,18 @@
return result;
}
- if (callLinkInfo.slowPathCount >= Options::couldTakeSlowCaseMinimumCount())
- return takesSlowPath();
+ CallLinkStatus result;
- JSFunction* target = callLinkInfo.lastSeenCallee.get();
- if (!target)
- return takesSlowPath();
+ if (JSFunction* target = callLinkInfo.lastSeenCallee.get()) {
+ CallVariant variant(target);
+ if (callLinkInfo.hasSeenClosure)
+ variant = variant.despecifiedClosure();
+ result.m_variants.append(variant);
+ }
- if (callLinkInfo.hasSeenClosure)
- return CallLinkStatus(target->executable());
+ result.m_couldTakeSlowPath = !!callLinkInfo.slowPathCount;
- return CallLinkStatus(target);
+ return result;
}
CallLinkStatus CallLinkStatus::computeFor(
