Regarding 8033626: C2: Merging exception state: reexecute=true vs reexecute=false
vladimir.x.ivanov at oracle.com
Wed May 28 16:37:13 UTC 2014
I'm looking at 8033626 :
"assert(ex_map->jvms()->same_calls_as(_exceptions->jvms())) failed: all
collected exceptions must come from the same place".
8014447  introduced new code shape for virtual intrinsifiable methods
(Object::hashCode & Object::clone): "invokevirtual Object.clone()" can
be represented as a PredictedCallGenerator with LibraryIntrinsic on fast
path and VirtualCallGenerator on slow path.
The problem arises for Object::clone, because for OOM case intrinsified
version requires reexecution (reexecute=true), but slow path (virtual
dispatch) doesn't (reexecute=false). Further attempt to finish the
diamond and merge 2 exception states fires the assertion.
So, I have 2 questions:
(1) I don't see any way to merge reexecute=true & reexecute=false
states, so both branches should have the same reexecute status. Am I
(2) Does PredictedCallGenerator actually support such shape
(intrinsic on fast path)? There are 2 call generators:
PredictedIntrinsicGenerator & PredictedCallGenerator. What's the
I see there's a way to customize predicate in
LibraryCallKit::try_to_predicate() for PredictedIntrinsicGenerator, but
is it the only reason why PredictedIntrinsicGenerator was introduced?
"Object.hashCode intrinsic breaks inline caches"
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