linux/tools/build
Wang Nan a940cad331 perf build: Check LLVM version in feature check
Cancel builtin llvm and clang support when LLVM version is less than
3.9.0: following commits uses newer API.

Since Clang/LLVM's API is not guaranteed to be stable, add a
test-llvm-version.cpp feature checker, issue warning if LLVM found in
compiling environment is not tested yet.

Committer Notes:

Testing it:

Environment:

  $ cat /etc/fedora-release
  Fedora release 25 (Twenty Five)
  $ rpm -q llvm-devel clang-devel
  llvm-devel-3.8.0-1.fc25.x86_64
  clang-devel-3.8.0-2.fc25.x86_64
  $

Before:

  $  make -k LIBCLANGLLVM=1 O=/tmp/build/perf -C tools/perf install-bin
  make: Entering directory '/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build
  Warning: tools/include/uapi/linux/bpf.h differs from kernel
  Warning: tools/arch/arm/include/uapi/asm/kvm.h differs from kernel
    INSTALL  GTK UI
    LINK     /tmp/build/perf/perf
  /tmp/build/perf/libperf.a(libperf-in.o): In function `perf::createCompilerInvocation(llvm::SmallVector<char const*, 16u>, llvm::StringRef&, clang::DiagnosticsEngine&)':
  /home/acme/git/linux/tools/perf/util/c++/clang.cpp:56: undefined reference to `clang::tooling::newInvocation(clang::DiagnosticsEngine*, llvm::SmallVector<char const*, 16u> const&)'
  /tmp/build/perf/libperf.a(libperf-in.o): In function `perf::getModuleFromSource(llvm::SmallVector<char const*, 16u>, llvm::StringRef, llvm::IntrusiveRefCntPtr<clang::vfs::FileSystem>)':
  /home/acme/git/linux/tools/perf/util/c++/clang.cpp:68: undefined reference to `clang::CompilerInstance::CompilerInstance(std::shared_ptr<clang::PCHContainerOperations>, bool)'
  /home/acme/git/linux/tools/perf/util/c++/clang.cpp:69: undefined reference to `clang::CompilerInstance::createDiagnostics(clang::DiagnosticConsumer*, bool)'
  <SNIP>

After:

  Makefile.config:807: No suitable libLLVM found, disabling builtin clang and llvm support. Please install llvm-dev(el) (>= 3.9.0)

Updating the environment to a locally built LLVM 4.0 + clang 3.9 (forgot
to git pull, duh) combo, all works as expected, it is properly detected
and built into the resulting perf binary.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161206072230.7651-1-wangnan0@huawei.com
[ Change the warning message a bit (add 'suitable' and 'builtin'), clarifying it, see committer notes above ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-12-06 13:21:55 -03:00
..
Documentation tools build: Add CFLAGS_REMOVE_* support 2016-11-14 11:37:25 -03:00
feature perf build: Check LLVM version in feature check 2016-12-06 13:21:55 -03:00
tests tools build: Build fixdep helper from perf and basic libs 2015-09-28 15:50:55 -03:00
.gitignore perf build: Add fixdep to .gitignore 2015-10-20 10:43:28 -03:00
Build tools build: Make fixdep a hostprog 2016-10-03 11:40:35 -03:00
Build.include tools build: Move tabs to spaces where suitable 2016-12-05 16:06:03 -03:00
fixdep.c tools build: Make fixdep parsing wait for last target 2016-12-05 15:51:42 -03:00
Makefile tools build: Make fixdep a hostprog 2016-10-03 11:40:35 -03:00
Makefile.build tools build: Support compiling C++ source file 2016-10-05 19:58:51 -03:00
Makefile.feature tools build: Move tabs to spaces where suitable 2016-12-05 16:06:03 -03:00
Makefile.include tools build: Make fixdep a hostprog 2016-10-03 11:40:35 -03:00