Re: [PATCH] selftests/exec: build with -fPIE instead of -pie, to make clang happy

From: John Hubbard
Date: Mon May 06 2024 - 15:09:05 EST


On 5/6/24 10:09 AM, Kees Cook wrote:
On Fri, May 03, 2024 at 07:23:01PM -0700, John Hubbard wrote:
clang doesn't deal well with "-pie -static": it warns that -pie is an
unused option here. Changing to "-fPIE -static" solves this problem for
clang, while keeping the gcc results identical.

The problem is visible when building via:

make LLVM=1 -C tools/testing/selftests

Again: gcc 13 produces identical binaries for all of these programs,
both before and after this commit (using "-pie"), and after (using
"-fPIE").

Also, the runtime results are the same for both clang and gcc builds.

Thanks for this! It got solved differently here:
https://lkml.kernel.org/r/20240416152831.3199999-1-usama.anjum@xxxxxxxxxxxxx

Does that work for you as well?


Yes it does. Please drop my patch and let's use yours instead, thanks!

(As an aside, outside of the compiler sources themselves, it has
proven quite difficult to find any in-depth documentation of linking
options and behavior--now, and in the past.)

thanks,
--
John Hubbard
NVIDIA