Re: [PATCH] gcc-plugins: disable under COMPILE_TEST

From: Emese Revfy
Date: Sun Jun 12 2016 - 18:06:02 EST


On Sat, 11 Jun 2016 12:29:26 -0400
Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> wrote:

> [[PATCH] gcc-plugins: disable under COMPILE_TEST] On 11/06/2016 (Sat 09:12) Kees Cook wrote:
>
> > Since adding the gcc plugin development headers is required for the
> > gcc plugin support, we should ease into this new kernel build dependency
> > more slowly. For now, disable the gcc plugins under COMPILE_TEST so that
> > all*config builds will skip it.
>
> Wouldn't it be better to test compile a one line program that tries to
> source the header(s) and then react accordingly?

The scripts/gcc-plugin.sh script does exactly that.

> Then at least you would get the test coverage from people who have the
> headers installed who are doing all[yes|mod]config. This "for now"
> solution doesn't really have a path forward other than assuming all
> distros install the plugin headers sometime in the future.
>
> Either way, this is an improvement over the current situation, so thanks
> for that.

If it is not too late I think this patch would be better:


When there is no gcc plugin support then don't compile the plugins
(but still print a warning). This allows building allyes/allmod configs
until the gcc plugin headers get installed.

Signed-off-by: Emese Revfy <re.emese@xxxxxxxxx>
---
Makefile | 6 +++---
scripts/Makefile.gcc-plugins | 8 ++++----
2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Makefile b/Makefile
index a49c075..715210c 100644
--- a/Makefile
+++ b/Makefile
@@ -623,15 +623,15 @@ endif
# Tell gcc to never replace conditional load with a non-conditional one
KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0)

+include scripts/Makefile.gcc-plugins
+
PHONY += gcc-plugins
gcc-plugins: scripts_basic
-ifdef CONFIG_GCC_PLUGINS
+ifneq ($(GCC_PLUGINS_CFLAGS),)
$(Q)$(MAKE) $(build)=scripts/gcc-plugins
endif
@:

-include scripts/Makefile.gcc-plugins
-
ifdef CONFIG_READABLE_ASM
# Disable optimizations that make assembler listings hard to read.
# reorder blocks reorders the control in the function
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index c7372cb..2f101ea 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -21,6 +21,7 @@ ifdef CONFIG_GCC_PLUGINS
CFLAGS_KCOV := $(SANCOV_PLUGIN)
else
$(warning warning: cannot use CONFIG_KCOV: -fsanitize-coverage=trace-pc is not supported by compiler)
+ CFLAGS_KCOV =
endif
endif
endif
@@ -37,13 +38,12 @@ ifdef CONFIG_GCC_PLUGINS
else
$(warning warning: your gcc version does not support plugins, you should upgrade it to gcc 4.5 at least)
endif
+ GCC_PLUGINS_CFLAGS =
endif
- else
- # SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication.
- GCC_PLUGINS_CFLAGS := $(filter-out $(SANCOV_PLUGIN), $(GCC_PLUGINS_CFLAGS))
endif

- KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS)
+ # SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication.
+ KBUILD_CFLAGS += $(filter-out $(SANCOV_PLUGIN), $(GCC_PLUGINS_CFLAGS))
GCC_PLUGIN := $(gcc-plugin-y)

endif

--
2.8.1