[cfe-dev] [LLVMdev] RFC: Dropping support for building sanitizers with autotools

[Alexey Samsonov]

On Tue, Feb 17, 2015 at 3:37 PM, Anna Zaks <ganna at apple.com> wrote:

> Unfortunately, we do rely on the Autotools to build for darwin.
>

> The lack of proper testing is very unfortunate. In the future, we will
> either drop the dependency on Makefile/autoconf build or add the support
> for sanitizer testing.
>

Sorry, for some reason I had the impression that you're also more
interested in CMake buiild :-/. Only now I noticed that recent Kuba's
patches about -isysroot fix both makefile and CMake
build system (and he's probably not very happy about it).

I believe the effort required to port sanitizer unit tests to autotools is
not worth it, and it's better to spend that time migrating the release
tools to CMake. Keeping two build systems "working"
was and is a manageable, but unpleasant burden. Providing a good test
coverage for two runtime versions is hard, and keeping two runtime versions
"equivalent" (built with the same compiler flags)
is close to impossible.

I understand that removing autotools support right now breaks your
integration. What if we just delete autotools support from all Linux builds?

Speaking of autotools support, I should lay out the reason why I raised the
question of removing it last week. We plan to make intrusive changes to
ASan and UBSan library layout:
1) embed UBSan runtime into ASan to solve various initialization and
integration problems of using ASan+UBSan (fixing
http://llvm.org/bugs/show_bug.cgi?id=21112)
2) make UBSan runtime standalone, and forbid to use it with another
sanitizers except for ASan.
Unfortunately, it means changing a bunch of build rules in *both* CMake and
makefile build.

Ideally, I would be happy to transfer ownership of current autotools build
on Darwin to you, and ask for help in implementing/testing necessary
changes on Mac OS X side :)
At the moment we don't even have a live buildbot running autotools-built
ASan on Mac, so you're in much better shape to catch and notice regressions.


> Anna.
>
> On Feb 17, 2015, at 10:54 AM, Kostya Serebryany <kcc at google.com> wrote:
>
> +1 (in case you still need mine)
>
> On Thu, Feb 12, 2015 at 6:31 PM, Alexey Samsonov <vonosmas at gmail.com>
> wrote:
>
>> Hi everyone,
>>
>> TL;DR I plan to do subj unless anyone objects.
>>
>> Autotools support for building sanitizers was never complete, is a proper
>> subset of CMake capabilities, and the gap between the features of CMake
>> build and autotools is quickly increasing:
>> 1) OS: autotools support Linux, Mac OS X and Android; CMake also supports
>> FreeBSD and Windows.
>> 2) Architectures: autotools support i386 and x86_64, CMake also supports
>> MIPS, ARM/AArch64, PowerPC).
>> 3) Library variants: autotools don't support building shared ASan runtime
>> on Linux.
>> 4 [!!!]) Autotools build doesn't have *any* support for building and
>> running tests.
>> 5) The sets of compiler flags we use to build runtimes are different in
>> two builds, and are hard to kept in sync.
>>
>> Because of (4), sanitizer runtimes built with autotools are severely
>> undertested, and maintaining two different build systems is a burden I
>> would like to get rid of. Now seems to be a good time for that: we've cut
>> off 3.6 release branch, and Hans assures me that 3.7 release process will
>> use CMake.
>>
>> Are there existing users of configure/make that want sanitizers to be
>> available in their build? Are there other arguments for keeping the
>> autotools build "working" I'm missing?
>>
>> --
>> Alexey Samsonov
>> vonosmas at gmail.com
>>
>
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>


-- 
Alexey Samsonov
vonosmas at gmail.com
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