Bug#833850: dpkg-dev: add per-architecture optimisation flags to dpkg-buildflags
Holger Levsen:
> Hi Ximin,
>
> On Tue, Aug 09, 2016 at 02:08:45PM +0200, Ximin Luo wrote:
>> Many software packages (e.g. see #833846) like to set optimisation flags based
>> on autodetecting CPU features of the build machine.
>
> do you really say/think that *many* packages in *Debian* have that
> behaviour? I'd not be surprised about *a few*, but many??!?
>
> and, do you know a way we could automatically detect/scan for those to
> file bugs? Those are all serious bugs…
>
I was exaggerating sorry. "some" would match better what I saw myself directly.
As for detection, we could get lintian to scan binary packages' pkg-config files and perhaps other code-looking files (i.e. not documentation) for "-march" and "-mcpu" and "-mtune" but this doesn't cover all cases.
We could also do the same for build logs.
We could also objdump -S binaries and check if they contain illegal instructions. For example that's how I detected the presence of AVX/FMA/SSE4 in linbox, e.g:
$ objdump -S /usr/lib/x86_64-linux-gnu/liblinbox.so | grep '\b\(ymm\|zmm\|vfm\)'
but I don't know binary to enough detail to suggest a full set of illegal instructions to search for.
X
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