diff mbox series

[1/1] tools build: Fix llvm feature detection, still used by bpftool

Message ID ZTGc8S293uaTqHja@kernel.org
State New
Headers
Series [1/1] tools build: Fix llvm feature detection, still used by bpftool |

Commit Message

Arnaldo Carvalho de Melo Oct. 19, 2023, 9:17 p.m. UTC 
  When removing the BPF event for perf a feature test that checks if the
llvm devel files are availabe was removed but that is also used by
bpftool.

bpftool uses it to decide what kind of disassembly it will use: llvm or
binutils based.

Removing the tools/build/feature/test-llvm.cpp file made bpftool to
always fallback to binutils disassembly, even with the llvm devel files
installed, fix it by restoring just that small test-llvm.cpp test file.

Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")
Reported-by: Manu Bretelle <chantr4@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Carsten Haitzler <carsten.haitzler@arm.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Fangrui Song <maskray@google.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: llvm@lists.linux.dev
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/lkml/ZTGa0Ukt7QyxWcVy@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/build/feature/test-llvm.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 tools/build/feature/test-llvm.cpp

Comments

Ian Rogers Oct. 19, 2023, 9:58 p.m. UTC | #1 
On Thu, Oct 19, 2023 at 2:17 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> When removing the BPF event for perf a feature test that checks if the
> llvm devel files are availabe was removed but that is also used by
> bpftool.
>
> bpftool uses it to decide what kind of disassembly it will use: llvm or
> binutils based.
>
> Removing the tools/build/feature/test-llvm.cpp file made bpftool to
> always fallback to binutils disassembly, even with the llvm devel files
> installed, fix it by restoring just that small test-llvm.cpp test file.
>
> Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")
> Reported-by: Manu Bretelle <chantr4@gmail.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Andrii Nakryiko <andrii@kernel.org>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Carsten Haitzler <carsten.haitzler@arm.com>
> Cc: Eduard Zingerman <eddyz87@gmail.com>
> Cc: Fangrui Song <maskray@google.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: James Clark <james.clark@arm.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: llvm@lists.linux.dev
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Quentin Monnet <quentin@isovalent.com>
> Cc: Ravi Bangoria <ravi.bangoria@amd.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
> Cc: Tom Rix <trix@redhat.com>
> Cc: Wang Nan <wangnan0@huawei.com>
> Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
> Cc: Yang Jihong <yangjihong1@huawei.com>
> Cc: Yonghong Song <yhs@fb.com>
> Cc: YueHaibing <yuehaibing@huawei.com>
> Link: https://lore.kernel.org/lkml/ZTGa0Ukt7QyxWcVy@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Sorry for the breakage.

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/build/feature/test-llvm.cpp | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>  create mode 100644 tools/build/feature/test-llvm.cpp
>
> diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
> new file mode 100644
> index 0000000000000000..88a3d1bdd9f6978e
> --- /dev/null
> +++ b/tools/build/feature/test-llvm.cpp
> @@ -0,0 +1,14 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "llvm/Support/ManagedStatic.h"
> +#include "llvm/Support/raw_ostream.h"
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +
> +#if NUM_VERSION < 0x030900
> +# error "LLVM version too low"
> +#endif
> +int main()
> +{
> +       llvm::errs() << "Hello World!\n";
> +       llvm::llvm_shutdown();
> +       return 0;
> +}
> --
> 2.41.0
>
Quentin Monnet Oct. 19, 2023, 10:01 p.m. UTC | #2 
On 19/10/2023 22:17, Arnaldo Carvalho de Melo wrote:
> When removing the BPF event for perf a feature test that checks if the
> llvm devel files are availabe was removed but that is also used by
> bpftool.
> 
> bpftool uses it to decide what kind of disassembly it will use: llvm or
> binutils based.
> 
> Removing the tools/build/feature/test-llvm.cpp file made bpftool to
> always fallback to binutils disassembly, even with the llvm devel files
> installed, fix it by restoring just that small test-llvm.cpp test file.
> 
> Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")
> Reported-by: Manu Bretelle <chantr4@gmail.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Andrii Nakryiko <andrii@kernel.org>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Carsten Haitzler <carsten.haitzler@arm.com>
> Cc: Eduard Zingerman <eddyz87@gmail.com>
> Cc: Fangrui Song <maskray@google.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: James Clark <james.clark@arm.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: llvm@lists.linux.dev
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Quentin Monnet <quentin@isovalent.com>
> Cc: Ravi Bangoria <ravi.bangoria@amd.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
> Cc: Tom Rix <trix@redhat.com>
> Cc: Wang Nan <wangnan0@huawei.com>
> Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
> Cc: Yang Jihong <yangjihong1@huawei.com>
> Cc: Yonghong Song <yhs@fb.com>
> Cc: YueHaibing <yuehaibing@huawei.com>
> Link: https://lore.kernel.org/lkml/ZTGa0Ukt7QyxWcVy@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/build/feature/test-llvm.cpp | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>  create mode 100644 tools/build/feature/test-llvm.cpp
> 
> diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
> new file mode 100644
> index 0000000000000000..88a3d1bdd9f6978e
> --- /dev/null
> +++ b/tools/build/feature/test-llvm.cpp
> @@ -0,0 +1,14 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "llvm/Support/ManagedStatic.h"
> +#include "llvm/Support/raw_ostream.h"
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +
> +#if NUM_VERSION < 0x030900
> +# error "LLVM version too low"
> +#endif
> +int main()
> +{
> +	llvm::errs() << "Hello World!\n";
> +	llvm::llvm_shutdown();
> +	return 0;
> +}

Acked-by: Quentin Monnet <quentin@isovalent.com>

Thanks Arnaldo, Manu!
Andrii Nakryiko Oct. 19, 2023, 10:47 p.m. UTC | #3 
On Thu, Oct 19, 2023 at 2:17 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> When removing the BPF event for perf a feature test that checks if the
> llvm devel files are availabe was removed but that is also used by
> bpftool.
>
> bpftool uses it to decide what kind of disassembly it will use: llvm or
> binutils based.
>
> Removing the tools/build/feature/test-llvm.cpp file made bpftool to
> always fallback to binutils disassembly, even with the llvm devel files
> installed, fix it by restoring just that small test-llvm.cpp test file.
>
> Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")

Should we route this through the bpf-next tree to get the fix for
bpftool into Github mirror ASAP?

> Reported-by: Manu Bretelle <chantr4@gmail.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Andrii Nakryiko <andrii@kernel.org>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Carsten Haitzler <carsten.haitzler@arm.com>
> Cc: Eduard Zingerman <eddyz87@gmail.com>
> Cc: Fangrui Song <maskray@google.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: James Clark <james.clark@arm.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: llvm@lists.linux.dev
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Quentin Monnet <quentin@isovalent.com>
> Cc: Ravi Bangoria <ravi.bangoria@amd.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
> Cc: Tom Rix <trix@redhat.com>
> Cc: Wang Nan <wangnan0@huawei.com>
> Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
> Cc: Yang Jihong <yangjihong1@huawei.com>
> Cc: Yonghong Song <yhs@fb.com>
> Cc: YueHaibing <yuehaibing@huawei.com>
> Link: https://lore.kernel.org/lkml/ZTGa0Ukt7QyxWcVy@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/build/feature/test-llvm.cpp | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>  create mode 100644 tools/build/feature/test-llvm.cpp
>
> diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
> new file mode 100644
> index 0000000000000000..88a3d1bdd9f6978e
> --- /dev/null
> +++ b/tools/build/feature/test-llvm.cpp
> @@ -0,0 +1,14 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "llvm/Support/ManagedStatic.h"
> +#include "llvm/Support/raw_ostream.h"
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +
> +#if NUM_VERSION < 0x030900
> +# error "LLVM version too low"
> +#endif
> +int main()
> +{
> +       llvm::errs() << "Hello World!\n";
> +       llvm::llvm_shutdown();
> +       return 0;
> +}
> --
> 2.41.0
>
Quentin Monnet Oct. 19, 2023, 10:50 p.m. UTC | #4 
On 19/10/2023 23:47, Andrii Nakryiko wrote:
> On Thu, Oct 19, 2023 at 2:17 PM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
>>
>> When removing the BPF event for perf a feature test that checks if the
>> llvm devel files are availabe was removed but that is also used by
>> bpftool.
>>
>> bpftool uses it to decide what kind of disassembly it will use: llvm or
>> binutils based.
>>
>> Removing the tools/build/feature/test-llvm.cpp file made bpftool to
>> always fallback to binutils disassembly, even with the llvm devel files
>> installed, fix it by restoring just that small test-llvm.cpp test file.
>>
>> Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")
> 
> Should we route this through the bpf-next tree to get the fix for
> bpftool into Github mirror ASAP?

It shouldn't be necessary. The GitHub mirror for bpftool uses its own
feature detection mechanism, and is not affected here. This patch won't
even make it to the mirror.

Quentin
Manu Bretelle Oct. 19, 2023, 10:52 p.m. UTC | #5 
On Thu, Oct 19, 2023 at 06:17:37PM -0300, Arnaldo Carvalho de Melo wrote:
> When removing the BPF event for perf a feature test that checks if the
> llvm devel files are availabe was removed but that is also used by
> bpftool.
> 
> bpftool uses it to decide what kind of disassembly it will use: llvm or
> binutils based.
> 
> Removing the tools/build/feature/test-llvm.cpp file made bpftool to
> always fallback to binutils disassembly, even with the llvm devel files
> installed, fix it by restoring just that small test-llvm.cpp test file.
> 
> Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")
> Reported-by: Manu Bretelle <chantr4@gmail.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Andrii Nakryiko <andrii@kernel.org>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Carsten Haitzler <carsten.haitzler@arm.com>
> Cc: Eduard Zingerman <eddyz87@gmail.com>
> Cc: Fangrui Song <maskray@google.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: James Clark <james.clark@arm.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: llvm@lists.linux.dev
> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Quentin Monnet <quentin@isovalent.com>
> Cc: Ravi Bangoria <ravi.bangoria@amd.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
> Cc: Tom Rix <trix@redhat.com>
> Cc: Wang Nan <wangnan0@huawei.com>
> Cc: Wang ShaoBo <bobo.shaobowang@huawei.com>
> Cc: Yang Jihong <yangjihong1@huawei.com>
> Cc: Yonghong Song <yhs@fb.com>
> Cc: YueHaibing <yuehaibing@huawei.com>
> Link: https://lore.kernel.org/lkml/ZTGa0Ukt7QyxWcVy@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/build/feature/test-llvm.cpp | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>  create mode 100644 tools/build/feature/test-llvm.cpp
> 
> diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
> new file mode 100644
> index 0000000000000000..88a3d1bdd9f6978e
> --- /dev/null
> +++ b/tools/build/feature/test-llvm.cpp
> @@ -0,0 +1,14 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "llvm/Support/ManagedStatic.h"
> +#include "llvm/Support/raw_ostream.h"
> +#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
> +
> +#if NUM_VERSION < 0x030900
> +# error "LLVM version too low"
> +#endif
> +int main()
> +{
> +	llvm::errs() << "Hello World!\n";
> +	llvm::llvm_shutdown();
> +	return 0;
> +}

Thanks for the quick turnaround!
diff mbox series

Patch

diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
new file mode 100644
index 0000000000000000..88a3d1bdd9f6978e
--- /dev/null
+++ b/tools/build/feature/test-llvm.cpp
@@ -0,0 +1,14 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/raw_ostream.h"
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+
+#if NUM_VERSION < 0x030900
+# error "LLVM version too low"
+#endif
+int main()
+{
+	llvm::errs() << "Hello World!\n";
+	llvm::llvm_shutdown();
+	return 0;
+}