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| author |   Masahiro Yamada <masahiroy@kernel.org> | 2020-12-03 21:57:00 +0900 |
|---|---|---|
| committer |   Kees Cook <keescook@chromium.org> | 2020-12-04 14:09:55 -0800 |
| commit | 1e860048c53ee77ee9870dcce94847a28544b753 (patch) | |
| tree | a18dd59f1a7eaa6ecb87658ea9b950f6c87ff5f8 | |
| parent | gcc-plugins: remove code for GCC versions older than 4.9 (diff) | |
| download | linux-dev-1e860048c53ee77ee9870dcce94847a28544b753.tar.xz linux-dev-1e860048c53ee77ee9870dcce94847a28544b753.zip | |
gcc-plugins: simplify GCC plugin-dev capability test
Linus pointed out a third of the time in the Kconfig parse stage comes
from the single invocation of cc1plus in scripts/gcc-plugin.sh [1],
and directly testing plugin-version.h for existence cuts down the
overhead a lot. [2]
This commit takes one step further to kill the build test entirely.
The small piece of code was probably intended to test the C++ designated
initializer, which was not supported until C++20.
In fact, with -pedantic option given, both GCC and Clang emit a warning.
$ echo 'class test { public: int test; } test = { .test = 1 };' | g++ -x c++ -pedantic - -fsyntax-only
<stdin>:1:43: warning: C++ designated initializers only available with '-std=c++2a' or '-std=gnu++2a' [-Wpedantic]
$ echo 'class test { public: int test; } test = { .test = 1 };' | clang++ -x c++ -pedantic - -fsyntax-only
<stdin>:1:43: warning: designated initializers are a C++20 extension [-Wc++20-designator]
class test { public: int test; } test = { .test = 1 };
^
1 warning generated.
Otherwise, modern C++ compilers should be able to build the code, and
hopefully skipping this test should not make any practical problem.
Checking the existence of plugin-version.h is still needed to ensure
the plugin-dev package is installed. The test code is now small enough
to be embedded in scripts/gcc-plugins/Kconfig.
[1] https://lore.kernel.org/lkml/CAHk-=wjU4DCuwQ4pXshRbwDCUQB31ScaeuDo1tjoZ0_PjhLHzQ@mail.gmail.com/
[2] https://lore.kernel.org/lkml/CAHk-=whK0aQxs6Q5ijJmYF1n2ch8cVFSUzU5yUM_HOjig=+vnw@mail.gmail.com/
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201203125700.161354-1-masahiroy@kernel.org
| -rwxr-xr-x | scripts/gcc-plugin.sh | 19 | ||||
| -rw-r--r-- | scripts/gcc-plugins/Kconfig | 2 |
2 files changed, 1 insertions, 20 deletions
diff --git a/scripts/gcc-plugin.sh b/scripts/gcc-plugin.sh deleted file mode 100755 index b79fd0bea838..000000000000 --- a/scripts/gcc-plugin.sh +++ /dev/null @@ -1,19 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0 - -set -e - -srctree=$(dirname "$0") - -gccplugins_dir=$($* -print-file-name=plugin) - -# we need a c++ compiler that supports the designated initializer GNU extension -$HOSTCC -c -x c++ -std=gnu++98 - -fsyntax-only -I $srctree/gcc-plugins -I $gccplugins_dir/include 2>/dev/null <<EOF -#include "gcc-common.h" -class test { -public: - int test; -} test = { - .test = 1 -}; -EOF diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index ae19fb0243b9..ab9eb4cbe33a 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -9,7 +9,7 @@ menuconfig GCC_PLUGINS bool "GCC plugins" depends on HAVE_GCC_PLUGINS depends on CC_IS_GCC - depends on $(success,$(srctree)/scripts/gcc-plugin.sh $(CC)) + depends on $(success,test -e $(shell,$(CC) -print-file-name=plugin)/include/plugin-version.h) default y help GCC plugins are loadable modules that provide extra features to the |