Hi Andy,
On Thu, Nov 8, 2018 at 2:02 AM Andy Shevchenko andy.shevchenko@gmail.com wrote:
On Mon, Oct 29, 2018 at 10:41:29PM +0800, Bin Meng wrote:
On Fri, Oct 26, 2018 at 8:41 PM Andy Shevchenko andy.shevchenko@gmail.com wrote:
On Fri, Oct 26, 2018 at 3:23 PM Bin Meng bmeng.cn@gmail.com wrote:
On Thu, Oct 25, 2018 at 10:55 PM Bin Meng bmeng.cn@gmail.com wrote:
On Thu, Oct 11, 2018 at 5:36 PM Andy Shevchenko andriy.shevchenko@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
Thanks! It seems compiler bug has been confirmed!
Yes, the bug is marked as a regression and a patch has been proposed.
P.S. Btw, I recommend to read a commit message to a proposed fix.
Good idea. However I read the fix commit message and have no idea on how to workaround in the U-Boot codes. Do you have any idea?
Regards, Bin