Re: [PATCH] Fix libcc1plugin and libc1plugin to avoid poisoned identifiers

[Dimitry Andric <dimitry@andric.com>]

On 13 Mar 2024, at 12:30, Iain Sandoe <iain@sandoe.co.uk> wrote:
> 
>> On 7 Mar 2024, at 16:48, Dimitry Andric <dimitry@andric.com> wrote:
>> 
>> Ref: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111632
>> 
>> Use INCLUDE_VECTOR before including system.h, instead of directly
>> including <vector>, to avoid running into poisoned identifiers.
> 
> I would say that the patch itself is obvious, but you have not mentioned how
> it was tested?

This was tested by doing a --disable-bootstrap build, on a FreeBSD
system where llvm-project's libc++ is the default C++ library
(specifically 15.0-CURRENT, which has llvm-project 17.0.6), against both
the lang/gcc14-devel port, and against gcc master as of
gcc-14-9346-g74e8cc28eda. This also required gcc-14-9360-g9970b576b7e to
be applied, before it was committed to master.

Note that if you do a fully bootstrapped build, there aren't any compile
errors, since it will compile the plugins against a freshly built
libstdc++: it has already transitively included <vector> via other
standard headers, so the #include <vector> statement after #include
"system.h" effectively does nothing, and won't run into poisoned
identifiers.

You would only get compile errors on those poisoned identifiers with the
non-bootstrapped, single-stage build which compiles everything against
the host system's C++ headers.

-Dimitry