From: Jiri Olsa <olsajiri@gmail.com>
To: "Björn Töpel" <bjorn@kernel.org>
Cc: "Arnaldo Carvalho de Melo" <acme@redhat.com>,
"Jean-Philippe Brucker" <jean-philippe@linaro.org>,
linux-kernel@vger.kernel.org, "Björn Töpel" <bjorn@rivosinc.com>,
"Nathan Chancellor" <nathan@kernel.org>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Tom Rix" <trix@redhat.com>,
bpf@vger.kernel.org, "Anders Roxell" <anders.roxell@linaro.org>,
llvm@lists.linux.dev
Subject: Re: [PATCH] tools/build: Add clang cross-compilation flags to feature detection
Date: Thu, 2 Nov 2023 10:29:58 +0100 [thread overview]
Message-ID: <ZUNsFkZWxws6c5Vx@krava> (raw)
In-Reply-To: <20231102081441.240280-1-bjorn@kernel.org>
On Thu, Nov 02, 2023 at 09:14:41AM +0100, Björn Töpel wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
>
> When a tool cross-build has LLVM=1 set, the clang cross-compilation
> flags are not passed to the feature detection build system. This
> results in the host's features are detected instead of the targets.
>
> E.g, triggering a cross-build of bpftool:
>
> cd tools/bpf/bpftool
> make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- LLVM=1
>
> would report the host's, and not the target's features.
>
> Correct the issue by passing the CLANG_CROSS_FLAGS variable to the
> feature detection makefile.
>
> Fixes: cebdb7374577 ("tools: Help cross-building with clang")
> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
> ---
> tools/build/Makefile.feature | 2 +-
> tools/build/feature/Makefile | 8 ++++----
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
> index 934e2777a2db..25b009a6c05f 100644
> --- a/tools/build/Makefile.feature
> +++ b/tools/build/Makefile.feature
> @@ -8,7 +8,7 @@ endif
>
> feature_check = $(eval $(feature_check_code))
> define feature_check_code
> - feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
> + feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" CLANG_CROSS_FLAGS="$(CLANG_CROSS_FLAGS)" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
> endef
>
> feature_set = $(eval $(feature_set_code))
> diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
> index dad79ede4e0a..0231a53024c7 100644
> --- a/tools/build/feature/Makefile
> +++ b/tools/build/feature/Makefile
> @@ -84,12 +84,12 @@ PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
>
> all: $(FILES)
>
> -__BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
> +__BUILD = $(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
> BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
> BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl
> BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap
>
> -__BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
> +__BUILDXX = $(CXX) $(CXXFLAGS) $(CLANG_CROSS_FLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
> BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
>
> ###############################
> @@ -259,10 +259,10 @@ $(OUTPUT)test-reallocarray.bin:
> $(BUILD)
>
> $(OUTPUT)test-libbfd-liberty.bin:
> - $(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
> + $(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
>
> $(OUTPUT)test-libbfd-liberty-z.bin:
> - $(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
> + $(CC) $(CFLAGS) $(CLANG_CROSS_FLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
should we add this also to test-compile-32.bin/test-compile-x32.bin
targets?
jirka
>
> $(OUTPUT)test-cplus-demangle.bin:
> $(BUILD) -liberty
>
> base-commit: 21e80f3841c01aeaf32d7aee7bbc87b3db1aa0c6
> --
> 2.40.1
>
>
next prev parent reply other threads:[~2023-11-02 9:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-02 8:14 [PATCH] tools/build: Add clang cross-compilation flags to feature detection Björn Töpel
2023-11-02 9:29 ` Jiri Olsa [this message]
2023-11-02 9:53 ` Björn Töpel
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