[U-Boot] [BUG] efi-x86_app_defconfig does not build with gcc 8.2

[Bin Meng]

Hi Andy,

On Fri, Oct 26, 2018 at 8:41 PM Andy Shevchenko
<andy.shevchenko at gmail.com> wrote:
>
> On Fri, Oct 26, 2018 at 3:23 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> > On Thu, Oct 25, 2018 at 10:55 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> > > On Thu, Oct 11, 2018 at 5:36 PM Andy Shevchenko
> > > <andriy.shevchenko at linux.intel.com> wrote:
>
> > > > That's what I was suspecting after looking how EFI applications are being built.
> > > >
> > > > So, someone familiar with compilers probably needs to check the following and act accordingly:
> > > > - either new compiler provides new switches to change behaviour as it was in GCC < 8, or
> > > > - create a small verifiable example with this linked list sections and submit a bug report to GCC, or
> > > > - U-Boot code (for linked lists) should be reconsidered from new requirements of the compiler, or
> > > > - EFI U-Boot application should have it's own relocation code (like normal U-Boot does), or
> > > > - ...anything I missed...
> > > >
> > > > The issue from my limited knowledge looks like this:
> > > > EFI loader relies on the sections that are natural for dynamically linked
> > > > libraries (AKA .so), while U-Boot (when runs on bare metal) has another
> > > > approach, i.e. specific code that does a relocation based only on .reloc
> > > > information. The linked list sections in U-Boot are meant to be statically
> > > > compiled, which is not the case for EFI by some reason.
> > > >
> > > > OTOH, it's clearly a compiler behaviour change, since with -fPIC -g it
> > > > generates DWARF that can't be translated by its own assembler!
> > > > (See option 2 in above list)
>
> > > Thank you for these useful suggestions! I will see if I can create a
> > > small test program to trigger this issue.
>
> > I created a small test case to trigger this issue. A workaround is to
> > disable '-Os' so that the test case pass. Of course disabling '-fpic'
> > also works. To me this looks like a bug when compiling pic codes with
> > optimization on. I will submit a bug report go GCC.
>
> Cool! Please, share the bug link whenever it will be filled, thanks!
>

Sure, though waited for some time to get my GCC Bugzilla created by the admin ..

Here it is: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87793

Regards,
Bin