forwarding to the ARM list for better visibility by the ARM team
Dan
On Tue, 25 Apr 2017 12:55:47 -0500
Dennis Gilmore <den...@ausil.us> wrote:
> El mar, 25-04-2017 a las 17:52 +0200, Jakub Jelinek escribió:
> > Hi!
> >
> > A severe ABI bug on AArch64 and especially on ARM 32-bit has been
> > recently discovered and GCC 7.1 is going to have that ABI change in.
> > For details see http://gcc.gnu.org/PR77728
> > gcc-7.1.1-0.16.fc{26,27} which I'll build tomorrow will contain the
> > ABI changes as well as a -Wpsabi diagnostics (note:) on code that is
> > changing the ABI.
> > The ABI change should affect primarily just C++ code passing PODs
> > by value where all the non-static data members and base classes are
> > at most
> > word aligned, but there are some static data members with doubleword
> > or bigger alignment or there are typedefs or other nested types in
> > the class/struct which are doubleword or bigger aligned, and are
> > passed
> > in certain positions in the argument list (passing them in even
> > registers
> > is fine, passing them in odd ones changes ABI, on the stack at odd
> > positions
> > might change the ABI too). For the typedefs, the broken ABI of GCC
> > 5.2 to 7.0.1
> > has been actually not even self-consitent in some templates, earlier
> > instantiation vs. lack thereof could affect the ABI. GCC 5.1 and
> > earlier
> > for structs used to match earlier AAPCS version and had different
> > rules and
> > issues.
> >
> > Could somebody from rel-eng perform a test mass rebuild on armv7hl
> > and aarch64 of F26 to determine which packages are affected by the
> > ABI changes so that we could rebuild only those that actually need
> > changing?
>
> We do not currently have resources or tooling to do test rebuilds. Do
> you have any idea what would be needed in order to do so?
>
> > If grepping for note: is not good enough for the test mass rebuild,
> > I could
> > hack up a test compiler that does something different when it
> > encounters
> > this (say abort if it encounters this and some special env var is
> > set,
> > or writes something into some /tmp/ file and let some brp script
> > collect
> > info from there, etc.).
>
> Dennis
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