Re: [PATCH] perf build: Support llvm and clang support compiled in

[Ian Rogers]

On Wed, Jul 12, 2023 at 3:07 AM Thomas Richter <tmricht@xxxxxxxxxxxxx> wrote:
>
> Perf build suports llvm and clang support compiled in.
> Test case 56 builtin clang support provides a test case
> which is always skipped.
>
> Link perf with the latest llvm and clang libraries and
> enable this test case.
>
> Use 'make LIBCLANGLLVM=1' to include this support.
>
> Output before:
>  # ./perf test 56
>  56: builtin clang support                  :
>  56.1: builtin clang compile C source to IR : Skip (not compiled in)
>  56.2: builtin clang compile C source to ELF object: \
>                                         Skip (not compiled in)
>
> Output after:
>  # ./perf test 56
>  56: builtin clang support                          :
>  56.1: builtin clang compile C source to IR         : Ok
>  56.2: builtin clang compile C source to ELF object : Ok
>  #
>
> Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
> Cc: Wang Nan <wangnan0@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/perf/Makefile.config | 2 +-
>  tools/perf/Makefile.perf   | 5 +----
>  2 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 0609c19caabd..a90af438261c 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -325,7 +325,7 @@ CORE_CFLAGS += -Wall
>  CORE_CFLAGS += -Wextra
>  CORE_CFLAGS += -std=gnu11
>
> -CXXFLAGS += -std=gnu++14 -fno-exceptions -fno-rtti
> +CXXFLAGS += -std=gnu++17 -fno-exceptions -fno-rtti
>  CXXFLAGS += -Wall
>  CXXFLAGS += -fno-omit-frame-pointer
>  CXXFLAGS += -ggdb3
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 097316ef38e6..d417d3fea818 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -426,10 +426,7 @@ EXTLIBS := $(call filter-out,$(EXCLUDE_EXTLIBS),$(EXTLIBS))
>  LIBS = -Wl,--whole-archive $(PERFLIBS) $(EXTRA_PERFLIBS) -Wl,--no-whole-archive -Wl,--start-group $(EXTLIBS) -Wl,--end-group
>
>  ifeq ($(USE_CLANG), 1)
> -  CLANGLIBS_LIST = AST Basic CodeGen Driver Frontend Lex Tooling Edit Sema Analysis Parse Serialization
> -  CLANGLIBS_NOEXT_LIST = $(foreach l,$(CLANGLIBS_LIST),$(shell $(LLVM_CONFIG) --libdir)/libclang$(l))
> -  LIBCLANG = $(foreach l,$(CLANGLIBS_NOEXT_LIST),$(wildcard $(l).a $(l).so))
> -  LIBS += -Wl,--start-group $(LIBCLANG) -Wl,--end-group
> +  LIBS += -lclang-cpp

This failed for:
```
  LINK    /tmp/perf/perf
/usr/bin/ld: cannot find -lclang-cpp: No such file or directory
collect2: error: ld returned 1 exit status
```

but adding the library directory fixed it:
```
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -426,7 +426,7 @@ EXTLIBS := $(call filter-out,$(EXCLUDE_EXTLIBS),$(EXTLIBS))
LIBS = -Wl,--whole-archive $(PERFLIBS) $(EXTRA_PERFLIBS)
-Wl,--no-whole-archive -Wl,--start-group $
(EXTLIBS) -Wl,--end-group

ifeq ($(USE_CLANG), 1)
-  LIBS += -lclang-cpp
+  LIBS += -L/usr/lib/llvm-15/lib -lclang-cpp
endif

ifeq ($(USE_LLVM), 1)
```

This is on a Debian installation:
```
$ dpkg -L libclang-cpp15
/.
/usr
/usr/lib
/usr/lib/llvm-15
/usr/lib/llvm-15/lib
/usr/lib/llvm-15/lib/libclang-cpp.so.15
/usr/lib/x86_64-linux-gnu
/usr/share
/usr/share/doc
/usr/share/doc/libclang-cpp15
/usr/share/doc/libclang-cpp15/NEWS.Debian.gz
/usr/share/doc/libclang-cpp15/changelog.Debian.gz
/usr/share/doc/libclang-cpp15/copyright
/usr/lib/x86_64-linux-gnu/libclang-cpp.so.15
```

Thanks,
Ian

>  endif
>
>  ifeq ($(USE_LLVM), 1)
> --
> 2.41.0
>