perf clang: Support compile IR to BPF object and add testcase

getBPFObjectFromModule() is introduced to compile LLVM IR(Module)
to BPF object. Add new testcase for it.

Test result:
  $ ./buildperf/perf test -v clang
  51: builtin clang support                               :
  51.1: builtin clang compile C source to IR              :
  --- start ---
  test child forked, pid 21822
  test child finished with 0
  ---- end ----
  builtin clang support subtest 0: Ok
  51.2: builtin clang compile C source to ELF object      :
  --- start ---
  test child forked, pid 21823
  test child finished with 0
  ---- end ----
  builtin clang support subtest 1: Ok

Signed-off-by: Wang Nan <wangnan0@huawei.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/20161126070354.141764-15-wangnan0@huawei.com
[ Remove redundant "Test" from entry descriptions ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 25 insertions, 6 deletions

diff --git a/tools/perf/util/c++/clang-test.cpp b/tools/perf/util/c++/clang-test.cpp
index d84e760d2aab..9b11e8c82798 100644
--- a/tools/perf/util/c++/clang-test.cpp
+++ b/tools/perf/util/c++/clang-test.cpp
@@ -13,15 +13,13 @@ public:
         ~perf_clang_scope() {perf_clang__cleanup();}
 };
 
-extern "C" {
-
-int test__clang_to_IR(void)
+static std::unique_ptr<llvm::Module>
+__test__clang_to_IR(void)
 {
-        perf_clang_scope _scope;
         unsigned int kernel_version;
 
         if (fetch_kernel_version(&kernel_version, NULL, 0))
-                return -1;
+                return std::unique_ptr<llvm::Module>(nullptr);
 
         std::string cflag_kver("-DLINUX_VERSION_CODE=" +
                                 std::to_string(kernel_version));
@@ -30,14 +28,35 @@ int test__clang_to_IR(void)
                 perf::getModuleFromSource({cflag_kver.c_str()},
                                           "perf-test.c",
                                           test_llvm__bpf_base_prog);
+        return M;
+}
+
+extern "C" {
+int test__clang_to_IR(void)
+{
+        perf_clang_scope _scope;
 
+        auto M = __test__clang_to_IR();
         if (!M)
                 return -1;
-
         for (llvm::Function& F : *M)
                 if (F.getName() == "bpf_func__SyS_epoll_wait")
                         return 0;
         return -1;
 }
 
+int test__clang_to_obj(void)
+{
+        perf_clang_scope _scope;
+
+        auto M = __test__clang_to_IR();
+        if (!M)
+                return -1;
+
+        auto Buffer = perf::getBPFObjectFromModule(&*M);
+        if (!Buffer)
+                return -1;
+        return 0;
+}
+
 }