Update raw_eq documentation and tests
#1091
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tedinski
approved these changes
Apr 22, 2022
| let uninit_arr: [u8; 8] = unsafe { MaybeUninit::uninit().assume_init() }; | ||
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| let arr_are_eq = unsafe { raw_eq(&zeroed_arr, &uninit_arr) }; | ||
| assert!(!arr_are_eq); |
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I'm not sure if this second test is necessary?
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It's expressing that raw_eq is also true in at least one trace, thus complementing the other test case.
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Description of changes:
First, I'm not clear on why I wrote that layout comparison was a requirement.
raw_eqis implemented asmemcmpand the documentation does not mention layout anywhere: https://doc.rust-lang.org/core/intrinsics/fn.raw_eq.htmlWhat it does mention is that uninitialized memory in any of the arguments is undefined behavior.
This PR updates the notes on Rust feature support to mention uninitialized memory, which we had to do anyways because of #920. It also updates the comment on
raw_eqand adds two new tests for checking the behavior with uninitialized data.I think there is nothing else to be done with
raw_equntil we can poison memory (see #920).Resolved issues:
Resolves #347
Part of #727
Testing:
How is this change tested? Adds two tests
Is this a refactor change? No
Checklist
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.