Bob Nystrom
21c5611bf0
The previous implementation unconditionally closed the first open upvalue when executing CLOSE_UPVALUE, which could crash when a local variable was never actually captured by a closure. Changed closeUpvalue to closeUpvalues with a stack threshold parameter, so only upvalues whose stack slot is at or above the given pointer are closed. This prevents closing nonexistent upvalues for locals that were never closed over, fixing segfaults in unused closure scenarios. Added regression tests for unused closures and for nested scopes where only some locals are captured.
20 lines
488 B
Plaintext
20 lines
488 B
Plaintext
// This is a regression test. When closing upvalues for discarded locals, it
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// wouldn't make sure it discarded the upvalue for the correct stack slot.
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//
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// Here we create two locals that can be closed over, but only the first one
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// actually is. When "b" goes out of scope, we need to make sure we don't
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// prematurely close "a".
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var closure
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{
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var a = "a"
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{
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var b = "b"
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closure = Fn.new { a }
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if (false) Fn.new { b }
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}
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System.print(closure.call()) // expect: a
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}
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