1359333 - Add support for detecting AES-NI

Status: RESOLVED FIXED

(Core :: mozglue, enhancement)

Comment 1

[Franziskus Kiefer [:franziskus]]

Attachment: Bug 1359333 - detect aes-ni support,

Review commit: https://reviewboard.mozilla.org/r/133308/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/133308/

Comment 2

[Nathan Froyd [:froydnj]]

Comment on attachment 8861327 [details]
Bug 1359333 - detect aes-ni support,

https://reviewboard.mozilla.org/r/133308/#review136866

glandium is on PTO for a while, stealing review.  I think if you just remove the `#define`, possibly with a comment about how there's no preprocessor symbol for AES support, things will work out as you expect.

::: mozglue/build/SSE.h:140
(Diff revision 1)
>  #endif
>  #ifdef __AVX2__
>    // It's ok to use AVX instructions based on the -march option.
>    #define MOZILLA_PRESUME_AVX2 1
>  #endif
> +#define MOZILLA_PRESUME_AES 0

This can't be right...

::: mozglue/build/SSE.h:222
(Diff revision 1)
>      extern bool MFBT_DATA avx_enabled;
>  #endif
>  #if !defined(MOZILLA_PRESUME_AVX2)
>      extern bool MFBT_DATA avx2_enabled;
>  #endif
> +#if !defined(MOZILLA_PRESUME_AES)

...because you're checking `!defined` in all these cases, and based on the above, `MOZILLA_PRESUME_AES` is always defined.

Comment 3

[Nathan Froyd [:froydnj]]

Comment on attachment 8861327 [details]
Bug 1359333 - detect aes-ni support,

Canceling glandium's review for reasons already stated.

Comment 4

[Franziskus Kiefer [:franziskus]]

Comment on attachment 8861327 [details]
Bug 1359333 - detect aes-ni support,

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/133308/diff/1-2/

Comment 5

[Nathan Froyd [:froydnj]]

Comment on attachment 8861327 [details]
Bug 1359333 - detect aes-ni support,

https://reviewboard.mozilla.org/r/133308/#review139680

r=me with the issue below fixed.  I think we should have

```
#ifdef __AES__
  // It's ok to use AES instructions based on the -march option.
  #define MOZILLA_PRESUME_AES 1
#endif
```

unless you disagree?

::: mozglue/build/SSE.h:140
(Diff revision 2)
>  #endif
>  #ifdef __AVX2__
>    // It's ok to use AVX instructions based on the -march option.
>    #define MOZILLA_PRESUME_AVX2 1
>  #endif
> +// There's no preprocessor symbol for __AES__

Really?  GCC 4.9 and above on my machine with `-march=native` define `__AES__`...

Comment 6

[Franziskus Kiefer [:franziskus]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/94600876bb6e45c6b73a4d7ff9bcec4c27bf2b28
Bug 1359333 - detect aes-ni support, r=froydnj

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/94600876bb6e