On Mon, Oct 26, 2020 at 10:51:43AM +0100, Paolo Bonzini wrote:
On 23/10/20 22:06, Daniele Buono wrote:
This patch allows to compile QEMU with link-time optimization (LTO).
Compilation with LTO is handled directly by meson. This patch adds checks
in configure to make sure the toolchain supports LTO.
Currently, allow LTO only with clang, since I have found a couple of issues
with gcc-based LTO.
In case fuzzing is enabled, automatically switch to llvm's linker (lld).
The standard bfd linker has a bug where function wrapping (used by the fuzz*
targets) is used in conjunction with LTO.
Tested with all major versions of clang from 6 to 12
Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
What are the problems like if you have GCC or you ar/linker are not up
to the job? I wouldn't mind omitting the tests since this has to be
enabled explicitly by the user.
We temporarily disabled LTO in Fedora rawhide due to GCC bugs causing
wierd test suite asserts. Those were pre-release versions of GCC/binutils
though. I've just tested again and LTO works correctly, so I've enabled
LTO once again.
Regards,
Daniel