Re: [PATCH 0/3] BaseTools GCC: pass CC flags to linker


Liming Gao
 

Ard:
I see Steven says it doesn't work, yet. So, I am curious what real issue is resolved by this patch?

Thanks
Liming

-----Original Message-----
From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
Sent: Wednesday, August 03, 2016 4:23 PM
To: Gao, Liming <liming.gao@intel.com>
Cc: Zhu, Yonghong <yonghong.zhu@intel.com>; Justen, Jordan L
<jordan.l.justen@intel.com>; edk2-devel@lists.01.org;
leif.lindholm@linaro.org; sigmaepsilon92@gmail.com
Subject: Re: [PATCH 0/3] BaseTools GCC: pass CC flags to linker

On 2 August 2016 at 16:51, Ard Biesheuvel <ard.biesheuvel@linaro.org>
wrote:
On 2 August 2016 at 16:50, Gao, Liming <liming.gao@intel.com> wrote:
Ard:
Without this change, GCC5 LTO can pass build. With it, what difference
will be in the generated image? Original way may generate the wrong image,
or new way will generate the smaller image?
This is not about code size but about correctness. Compiler switches
for code model or alignment etc may affect the way code is generated
at link time by the LTO routines.
Note that Steven mentions a similar problem in his CLANG38 series: he
needs to pass -pie to the linker (or -fpie would be sufficient, I
suspect) to prevent the linker from using the wrong code model when
generating code from the LTO bytecode.

Thanks,
Ard.

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