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inline asm!: ban OpReturn/OpReturnValue (they're always UB).#1006
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eddyb merged 5 commits intoEmbarkStudios:mainfrom Mar 18, 2023
LykenSol:no-asm-ret
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inline asm!: ban OpReturn/OpReturnValue (they're always UB).#1006eddyb merged 5 commits intoEmbarkStudios:mainfrom LykenSol:no-asm-ret
OpReturn/OpReturnValue (they're always UB).#1006eddyb merged 5 commits intoEmbarkStudios:mainfrom
LykenSol:no-asm-ret
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oisyn
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Mar 18, 2023
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This PR fixes #1002 by banning the misuse of inline
asm!(see the issue for more details).We used to get away with the UB, but now MIR inlining is wreaking havoc (e.g. inlining
asm!("ret")will return from the caller it was inlined into - one of the many ways in which the UB can manifest).Most of this PR is actually making progress towards:
MaybeUninit#981However, I'm not considering #981 as being fixed just yet, because the original usecase involves arrays, which have their own complications, and I focused on only opaque handles (as
AccelerationStructureconstructors need it).I've also not changed any unaffected use of
asm!, leaving the migration toMaybeUninitfor an issue:asm!should useMaybeUninit<T>instead oflet mut result = T::default();. #1007Each commit should be reviewed separately (or maybe I should've split this into two PRs?).