Add proper error for attempted use of undef slot #50556
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Fixes the segfault in #50518 and turns it into a proper error at both the syntax level (to catch lowering generating bad slot references) as well as at the codegen level (to catch e.g. bad generated functions and opaque closures). However, note that the latter case is technically undefined behavior, because we do not model the possibility that an otherwise-defined argument could throw at access time. Of course, throwing an error is allowable as undefined behavior and preferable to a segfault.
Keno
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Jul 14, 2023
Fixes the case from #50518, but we actually have two test cases in the tests that also hit this (e.g. this one: ``` f40964(xs::Int...=1; k = 2) = (xs, k) ```), but just happened not to hit the bad codegen path. #50556, once merged would have complained on those definitions as well, without this fix.
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#50559 needs to be merged first for this not to error, since we actually had a test that triggered the bad lowering. |
vtjnash
approved these changes
Jul 15, 2023
| @@ -296,7 +296,7 @@ | |||
| (if (eq? n '|#self#|) (gensy) n)) | |||
| arg-names)))) | |||
| (let ((body (insert-after-meta body ;; don't specialize on generator arguments | |||
| `((meta nospecialize ,@arg-names))))) | |||
| `((meta nospecialize ,@(map (lambda (idx) `(slot ,(+ idx 1))) (iota (length arg-names)))))))) | |||
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IIRC, there was previously a bug (and open issue) that vararg arguments didn't get nospecialize'd for macros. Any idea if this fixed it?
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I don't think so. This is for generated functions.
github-merge-queue bot
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Jul 15, 2023
Fixes the case from #50518, but we actually have two test cases in the tests that also hit this (e.g. this one: ``` f40964(xs::Int...=1; k = 2) = (xs, k) ``` ), but just happened not to hit the bad codegen path. #50556, once merged would have complained on those definitions as well, without this fix.
I agree with this, but that's a pre-existing issue. I wouldn't really have a problem with ripping out the whole special |
Keno
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Jul 17, 2023
I had an off-by-one in #50556, since the argument slots actually start at 2 and `iota` starts at `0`. This was breaking StaticArrays precompiles, which attempts to precompile a generator with its abstract signature and without the nospecialize, those signatures are not compileable.
KristofferC
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Jul 17, 2023
Fixes the case from #50518, but we actually have two test cases in the tests that also hit this (e.g. this one: ``` f40964(xs::Int...=1; k = 2) = (xs, k) ```), but just happened not to hit the bad codegen path. #50556, once merged would have complained on those definitions as well, without this fix. (cherry picked from commit c272236)
Keno
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Jul 18, 2023
I had an off-by-one in #50556, since the argument slots actually start at 2 and `iota` starts at `0`. This was breaking StaticArrays precompiles, which attempts to precompile a generator with its abstract signature and without the nospecialize, those signatures are not compileable. Co-authored-by: Oscar Smith <oscardssmith@gmail.com>
KristofferC
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Aug 10, 2023
Fixes the case from #50518, but we actually have two test cases in the tests that also hit this (e.g. this one: ``` f40964(xs::Int...=1; k = 2) = (xs, k) ```), but just happened not to hit the bad codegen path. #50556, once merged would have complained on those definitions as well, without this fix. (cherry picked from commit c272236)
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Fixes the segfault in #50518 and turns it into a proper error at both the syntax level (to catch lowering generating bad slot references) as well as at the codegen level (to catch e.g. bad generated functions and opaque closures). However, note that the latter case is technically undefined behavior, because we do not model the possibility that an otherwise-defined argument could throw at access time. Of course, throwing an error is allowable as undefined behavior and preferable to a segfault.