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Re: [PATCH 13/13] Installed header hygiene (BZ#20366): Test of installed headers.
- From: Carlos O'Donell <carlos at redhat dot com>
- To: Zack Weinberg <zackw at panix dot com>, libc-alpha at sourceware dot org
- Cc: joseph at codesourcery dot com
- Date: Wed, 21 Sep 2016 16:12:12 -0400
- Subject: Re: [PATCH 13/13] Installed header hygiene (BZ#20366): Test of installed headers.
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On 08/29/2016 09:16 PM, Zack Weinberg wrote:
> As the final act in this patchset, this adds a test to make sure that
> the bugs I've been fixing stay fixed. Each subdirectory checks each
> of the headers that it installs for two properties:
> * A source file that includes that header as (nearly) its first
> action, includes no other headers, and makes one global definition
> ("int avoid_empty_translation_unit;") will compile successfully, as
> both C and C++, at a variety of language and library conformance
> levels. (I did not go for the full cross product mainly because
> that would take ages, and also I'd have to know more about which
> -std= options the compiler understands. I think the set I picked
> makes sense, but am happy to take feedback about what's
> * None of the headers transitively included by that source file
> contain any tokens that match a regexp-based blacklist: this is
> currently enforcing non-use of the obsolete BSD u_* types.
> In order for this test to work correctly, every wrapper header
> that actually defines something must guard those definitions with
> #ifndef _ISOMAC. This is the existing mechanism used by the conform/
> tests to tell wrapper headers not to define anything that the public
> header wouldn't, and not to use anything from libc-symbols.h. conform/
> only cares for headers that we need to check for standards conformance,
> whereas this test applies to *every* header. (Headers in include/ that
> are either installed directly, or are internal-use-only and do *not*
> correspond to any installed header, are not affected.)
> The wrapper header adjustments were semi-mechanically generated, but I
> had to correct enough problems by hand that I don't think posting the
> script is worth it.
We minimally require gcc 4.7 to build glibc, and 4.7 was the fist to
includes support for -std=c11, so your set of tested modes looks good.
Similarly by gcc 4.7 the -std=c++11 support was almost complete, so
this is also OK.
As a whole this patch looks good to me. I appreciate that you included
testing in this patch set to prevent the changes from regressing.
I don't have a strong opinion about how this testing should be
architected, and what you have seems sensible at a high level.
I looked over the patches from a correctness perspective and I don't
see anything that jumps out as obviously wrong.
I would like someone else like Joseph to comment on the design though
since his experience maintaining conform tests would be useful here.