7.0.0 update to 8.9.0 PIC register clobbered

[Phil C]

CentOS 7..2009

gcc 4.8.5-44

I am updating from cryptopp 7.0.0 to 8..0 and receive the following error

gcm.cpp: In member function 'virtual size_t CryptoPP::GCM_Base::AuthenticateBlocks(const byte*, size_t)':

gcm.cpp:733:18: error: PIC register clobbered by '%ebx' in 'asm'

Is the correct solution to remove -fPIC from the makefile?

(other than updating to a newer compiler....)

[Jeffrey Walton]

I believe this is a false positive. EBX is saved, and then restored around <https://github.com/weidai11/cryptopp/blob/master/gcm.cpp#L717>.

Jeff

[Phil C]

Thank you for looking at it. I believe this is a compiler issue that has been corrected in gcc. I do not get the issue with gcc 12.2.0 on a test debian system. Unfortunately I need to use the old c7 / gcc combination.

[Phil C]

I should also note that I am compiling to link with a 32bit application, so including -Wa,--32 -m32