[PATCH] gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS again

From: Arnd Bergmann
Date: Wed Dec 11 2019 - 08:40:20 EST

I noticed that randconfig builds with gcc no longer produce a lot of
ccache hits, unlike with clang, and traced this back to plugins
now being enabled unconditionally if they are supported.

I am now working around this by adding

export CCACHE_COMPILERCHECK=/usr/bin/size -A %compiler%

to my top-level Makefile. This changes the heuristic that ccache uses
to determine whether the plugins are the same after a 'make clean'.

However, it also seems that being able to just turn off the plugins is
generally useful, at least for build testing it adds noticeable overhead
but does not find a lot of bugs additional bugs, and may be easier for
ccache users than my workaround.

Fixes: 9f671e58159a ("security: Create "kernel hardening" config area")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
scripts/gcc-plugins/Kconfig | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index d33de0b9f4f5..e3569543bdac 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -14,8 +14,8 @@ config HAVE_GCC_PLUGINS
An arch should select this symbol if it supports building with
GCC plugins.

- bool
+menuconfig GCC_PLUGINS
+ bool "GCC plugins"
depends on PLUGIN_HOSTCC != ""
default y
@@ -25,8 +25,7 @@ config GCC_PLUGINS

See Documentation/core-api/gcc-plugins.rst for details.

-menu "GCC plugins"
- depends on GCC_PLUGINS

bool "Compute the cyclomatic complexity of a function" if EXPERT
@@ -113,4 +112,4 @@ config GCC_PLUGIN_ARM_SSP_PER_TASK
depends on GCC_PLUGINS && ARM