2021-09-15 09:24:57

by Dan Li

Subject: [PATCH] [RFC] Add additional include path for gcc plugins

When kernel enables gcc plugin, some header files are missing in some
tool chains (as in the following example)

These header files can be found in other toolchains, and sometimes
the md5hash of these files are same(in most versions).

Should we add a parameter to plugin to allow users to import their own
header file directories?

---
HOSTCXX scripts/gcc-plugins/stackleak_plugin.so
In file included from scripts/gcc-plugins/gcc-common.h:103:0,
from scripts/gcc-plugins/stackleak_plugin.c:30:
/workspace/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/bin/../
lib/gcc/aarch64-none-linux-gnu/9.2.1/plugin/include/builtins.h:23:17:
fatal error: mpc.h: No such file or directory
#include <mpc.h>

Signed-off-by: Dan Li <[email protected]>
---
Makefile | 3 +++
scripts/gcc-plugins/Makefile | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 09bb314..e6134f3 100644
--- a/Makefile
+++ b/Makefile
@@ -1036,6 +1036,9 @@ include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan
include-$(CONFIG_KCOV) += scripts/Makefile.kcov
include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins

+GCC_PLUGINS_EXT_CFLAGS=
+export GCC_PLUGINS_EXT_CFLAGS
+
include $(addprefix $(srctree)/, $(include-y))

# scripts/Makefile.gcc-plugins is intentionally included last.
diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index 1952d3b..0b3e27a 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -23,7 +23,7 @@ GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)

plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
-include $(srctree)/include/linux/compiler-version.h \
- -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \
+ -I $(GCC_PLUGINS_DIR)/include -I $(obj) $(GCC_PLUGINS_EXT_CFLAGS) -std=gnu++11 \
-fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
-ggdb -Wno-narrowing -Wno-unused-variable \
-Wno-format-diag
--
2.7.4

2021-09-15 10:03:07

by Masahiro Yamada

Subject: Re: [PATCH] [RFC] Add additional include path for gcc plugins

On Wed, Sep 15, 2021 at 6:23 PM Dan Li <[email protected]> wrote:
>
> When kernel enables gcc plugin, some header files are missing in some
> tool chains (as in the following example)
>
> These header files can be found in other toolchains, and sometimes
> the md5hash of these files are same(in most versions).
>
> Should we add a parameter to plugin to allow users to import their own
> header file directories?
>
> ---
> HOSTCXX scripts/gcc-plugins/stackleak_plugin.so
> In file included from scripts/gcc-plugins/gcc-common.h:103:0,
> from scripts/gcc-plugins/stackleak_plugin.c:30:
> /workspace/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/bin/../
> lib/gcc/aarch64-none-linux-gnu/9.2.1/plugin/include/builtins.h:23:17:
> fatal error: mpc.h: No such file or directory
> #include <mpc.h>


gcc-plugins are compiled by the host compiler (usually g++).
Kbuild already provides 'HOSTCXXFLAGS'
to pass-in additional flags to it.

But, if you need to tweak include paths, you are already screwed up, maybe.

Some time ago, I got a question about plugin builds failing due to missing gmp.h
but it was solvable by installing a package.

https://lore.kernel.org/all/CAK7LNART2qQBY7Vc8rhMiXS_Fwty7qpWjwwfPrUegTb-gjy6sA@mail.gmail.com/






> Signed-off-by: Dan Li <[email protected]>
> ---
> Makefile | 3 +++
> scripts/gcc-plugins/Makefile | 2 +-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 09bb314..e6134f3 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1036,6 +1036,9 @@ include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan
> include-$(CONFIG_KCOV) += scripts/Makefile.kcov
> include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins
>
> +GCC_PLUGINS_EXT_CFLAGS=
> +export GCC_PLUGINS_EXT_CFLAGS
> +
> include $(addprefix $(srctree)/, $(include-y))
>
> # scripts/Makefile.gcc-plugins is intentionally included last.
> diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
> index 1952d3b..0b3e27a 100644
> --- a/scripts/gcc-plugins/Makefile
> +++ b/scripts/gcc-plugins/Makefile
> @@ -23,7 +23,7 @@ GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
>
> plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
> -include $(srctree)/include/linux/compiler-version.h \
> - -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \
> + -I $(GCC_PLUGINS_DIR)/include -I $(obj) $(GCC_PLUGINS_EXT_CFLAGS) -std=gnu++11 \
> -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
> -ggdb -Wno-narrowing -Wno-unused-variable \
> -Wno-format-diag
> --
> 2.7.4
>


--
Best Regards
Masahiro Yamada