perf tests: Add LLVM test for eBPF on-the-fly compiling

Previous patches introduce llvm__compile_bpf() to compile source file to
eBPF object. This patch adds testcase to test it. It also tests libbpf
by opening generated object after applying next patch which introduces
HAVE_LIBBPF_SUPPORT option.

Since llvm__compile_bpf() prints long messages which users who don't
explicitly test llvm doesn't care, this patch set verbose to -1 to
suppress all debug, warning and error message, and hint user use 'perf
test -v' to see the full output.

For the same reason, if clang is not found in PATH and there's no [llvm]
section in .perfconfig, skip this test.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/n/1436445342-1402-17-git-send-email-wangnan0@huawei.com
[ Add tools/lib/bpf/ to tools/perf/MANIFEST, so that the tarball targets build ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/llvm-utils.h b/tools/perf/util/llvm-utils.h
index d23adbc..5b3cf1c 100644
--- a/tools/perf/util/llvm-utils.h
+++ b/tools/perf/util/llvm-utils.h
@@ -29,6 +29,13 @@
 	 * compiling. Should not be used for dynamic compiling.
 	 */
 	const char *kbuild_opts;
+	/*
+	 * Default is false. If one of the above fields is set by user
+	 * explicitly then user_set_llvm is set to true. This is used
+	 * for perf test. If user doesn't set anything in .perfconfig
+	 * and clang is not found, don't trigger llvm test.
+	 */
+	bool user_set_param;
 };
 
 extern struct llvm_param llvm_param;
@@ -36,4 +43,7 @@
 
 extern int llvm__compile_bpf(const char *path, void **p_obj_buf,
 			     size_t *p_obj_buf_sz);
+
+/* This function is for test__llvm() use only */
+extern int llvm__search_clang(void);
 #endif