llvm dev - Jan 2013 - [LLVMdev] RFC: Promote AArch64 to be built by default

Hi all,

We'd like to promote the AArch64 backend to being built by default. I
know it's very soon after the initial upload, but we think the backend
is in a good position and should be stable.

We'd very much like to get it tested in more diverse environments
provided by the buildbots, and are committed to cleaning up any
fallout as soon as possible, or as a last resort reverting the
"enable" commit.

As before, this doesn't affect our attitude to more reviews: they
would be very welcome.

Does anyone object to me making the necessary changes?

Cheers.

Tim.

On Thu, Jan 31, 2013 at 4:37 AM, Tim Northover <t.p.northover at
gmail.com>wrote:
> Hi all,
>
> We'd like to promote the AArch64 backend to being built by default. I
> know it's very soon after the initial upload, but we think the backend
> is in a good position and should be stable.
>
> We'd very much like to get it tested in more diverse environments
> provided by the buildbots, and are committed to cleaning up any
> fallout as soon as possible, or as a last resort reverting the
> "enable" commit.
>
> As before, this doesn't affect our attitude to more reviews: they
> would be very welcome.
>
> Does anyone object to me making the necessary changes?
>
I'll own up to suggesting this on IRC. =]

Here is my rationale:
- Tim and others working on the backend have worked with the community for
a while now.
- Tim was particularly diligent in splitting off independent changes, and
all of those are already in place.
- There seems to be broad community support for the backend, so it seems
unlikely to be neglected.

This to me says that the concerns and protections of the experimental
backend aren't needed, and are more likely to impede progress than help it
-- specifically, we won't get good build bot coverage and diverse host
compiler coverage until it's enabled.

My 2-cents.
-Chandler
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On 31 January 2013 12:45, Chandler Carruth <chandlerc at google.com>
wrote:
> This to me says that the concerns and protections of the experimental
> backend aren't needed, and are more likely to impede progress than help
it
> -- specifically, we won't get good build bot coverage and diverse host
> compiler coverage until it's enabled.
>
+1

--renato
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On Jan 31, 2013, at 4:37 AM, Tim Northover <t.p.northover at gmail.com>
wrote:
> Hi all,
> 
> We'd like to promote the AArch64 backend to being built by default. I
> know it's very soon after the initial upload, but we think the backend
> is in a good position and should be stable.
> 
> We'd very much like to get it tested in more diverse environments
> provided by the buildbots, and are committed to cleaning up any
> fallout as soon as possible, or as a last resort reverting the
> "enable" commit.
> 
> As before, this doesn't affect our attitude to more reviews: they
> would be very welcome.
> 
> Does anyone object to me making the necessary changes?

I think this is the right thing to do. Once you've resolved the Mac and
Windows issues, go for it.

	- Doug

> I think this is the right thing to do. Once you've resolved the Mac and
Windows issues, go for it.
Thanks Doub. Just to let people know what happened. I enabled in
r174322 around lunchtime. Here's a report of the noticed failures with
status (important/outstanding ones at the top). Feel free to do
anything from telling me about more problems to reverting the patch
when llvm.org comes up.

http://lab.llvm.org:8011/builders/clang-x86_64-ubuntu-gdb-75/builds/1892:
    Didn't rerun configure. If anyone has access to this, forcing it
would be very helpful.
Shared library builds on OSX fail (cyclic dependency):
    I hope to post a patch this evening.
http://lab.llvm.org:8011/builders/clang-x86_64-darwin11-self-mingw32/builds/9058
    There are warnings in AArch64 code. I'll fix them tomorrow. There
may be more warnings not yet noticed, I've been fighting actual
failures today.

The rest are believed resolved:

http://lab.llvm.org:8011/builders/clang-x86_64-darwin11-self-mingw32/builds/9057:
    Improper 33-bit integer constant. Fixed in r174324.
http://bb.pgr.jp/builders/cmake-clang-i686-msvc10/builds/1850
    Improper use of StringRef causing errors when compiler is MSVC
(fixed in r174328)
http://bb.pgr.jp/builders/clang-i686-msys/builds/409:
    llvm-config reported an error, believed to be the result of
incomplete configure step. 410 succeeded.
http://lab.llvm.org:8011/builders/llvm-mips-linux/builds/862:
    Semi-regular timeout?

Cheers.

Tim.