[PATCH] D96164: [lld-macho] add code signature for native arm64 macOS

Mon Feb 15 05:46:12 PST 2021

thakis added a comment.

In D96164#2562720 <https://reviews.llvm.org/D96164#2562720>, @gkm wrote:

> In D96164#2562701 <https://reviews.llvm.org/D96164#2562701>, @gkm wrote:
>
>> In D96164#2562655 <https://reviews.llvm.org/D96164#2562655>, @thakis wrote:
>>
>>> Re the copy stuff: See the CL desc and openradar link in https://reviews.llvm.org/rGba3bc2fd41b8428904fc779e353d3769074d8982
>>
>> That is good to know. This case differs: LLD is not overwriting an existing file, so is not reusing an vnode. There is something funky in `FileOutputBuffer`, which creates the LLD output file via mmap(2).
>
> Travis Hill <travis at xojo.com> fed me the answer. The Go peeps had the same problem: https://go-review.googlesource.com/c/go/+/272258
> The Darwin kernel caches signature verification results by vnode. mmap(2) creates the cache entry, before we have written anything to the output. The fix is to invalidate the cache after writing via `msync(..., MS_INVALIDATE);`

Ah, the mmap one is https://openradar.appspot.com/FB8914231 :)

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https://reviews.llvm.org/D96164