Fix missing GC root in the presence of try/catch #22516
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Since try/catch (returns_twice at the LLVM level) can have control flow edges not visible to LLVM, we need to be very conservative here. In order to fix correctness, simply make sure that a value that is live across a sigsetjmp gets frozen in its own dedicated GC slot. There's fancier schemes we could attempt, but they would rely on expressing the exception edges in LLVM IR in one way or another.
vtjnash
approved these changes
Jun 25, 2017
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Since try/catch (returns_twice at the LLVM level) can have control flow
edges not visible to LLVM, we need to be very conservative here. In
order to fix correctness, simply make sure that a value that is live
across a sigsetjmp gets frozen in its own dedicated GC slot. There's
fancier schemes we could attempt, but they would rely on expressing
the exception edges in LLVM IR in one way or another.