gcov: disable for COMPILE_TEST

commit cc622420798c4bcf093785d872525087a7798db9 upstream.

Enabling gcov is counterproductive to compile testing: it significantly
increases the kernel image size, compile time, and it produces lots
of false positive "may be used uninitialized" warnings as the result
of missed optimizations.

This is in line with how UBSAN_SANITIZE_ALL and PROFILE_ALL_BRANCHES
work, both of which have similar problems.

With an ARM allmodconfig kernel, I see the build time drop from
283 minutes CPU time to 225 minutes, and the vmlinux size drops
from 43MB to 26MB.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 3b7408759bdfdfc4a5fe469df649d631efdae40d..23153a692637ca50b20699a2dfadaadf89465424 100644 (file)
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -34,6 +34,7 @@ config GCOV_KERNEL
 
 config GCOV_PROFILE_ALL
        bool "Profile entire Kernel"
+       depends on !COMPILE_TEST
        depends on GCOV_KERNEL
        depends on SUPERH || S390 || X86 || PPC || MICROBLAZE || ARM || ARM64
        default n