[edk2-devel] [PATCH v7 1/3] BaseTools: Remove COMMON section from the GCC discard list

[Ard Biesheuvel]

On Wed, 21 Jul 2021 at 13:44, Yao, Jiewen <jiewen.yao at intel.com> wrote:
>
> Acked-by: Jiewen Yao <Jiewen.yao at intel.com>
>

I don't think this is a good idea tbh. We have already identified that
EDK2 code often fails to use the STATIC keyword when possible for
global variables, and that unrelated variables that happen to have the
same name will be collapsed into the same storage unit in the program
image. (see commit 214a3b79417f64bf2faae74af42c1b9d23f50dc8 for
details)

Was this considered? Is this no longer an issue?



> > -----Original Message-----
> > From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Christopher
> > Zurcher
> > Sent: Wednesday, July 21, 2021 6:07 AM
> > To: devel at edk2.groups.io
> > Cc: Ard Biesheuvel <ardb at kernel.org>; Feng, Bob C <bob.c.feng at intel.com>;
> > Liming Gao <gaoliming at byosoft.com.cn>
> > Subject: [edk2-devel] [PATCH v7 1/3] BaseTools: Remove COMMON section
> > from the GCC discard list
> >
> > From: Christopher Zurcher <christopher.zurcher at microsoft.com>
> >
> > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2507
> >
> > The COMMON section is used by OpenSSL assembly-optimized crypto
> > functions. OpenSSL assembly code is auto-generated from the submodule
> > and cannot be modified to remove dependence on the COMMON section.
> > The default -fno-common compiler flag should still prevent variable from
> > being emitted into the COMMON section.
> >
> > Cc: Ard Biesheuvel <ardb at kernel.org>
> > Cc: Bob Feng <bob.c.feng at intel.com>
> > Cc: Liming Gao <gaoliming at byosoft.com.cn>
> > Signed-off-by: Christopher Zurcher <christopher.zurcher at microsoft.com>
> > ---
> >  BaseTools/Scripts/GccBase.lds | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/BaseTools/Scripts/GccBase.lds b/BaseTools/Scripts/GccBase.lds
> > index a9dd2138d4..83cebd29d5 100644
> > --- a/BaseTools/Scripts/GccBase.lds
> > +++ b/BaseTools/Scripts/GccBase.lds
> > @@ -74,6 +74,5 @@ SECTIONS {
> >      *(.dynamic)
> >      *(.hash .gnu.hash)
> >      *(.comment)
> > -    *(COMMON)
> >    }
> >  }
> > --
> > 2.32.0.windows.1
> >
> >
> >
> > 
> >
>


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