perf test: Fix build of BPF and LLVM on older glibc libraries

  $ rpm -q glibc
  glibc-2.12-1.166.el6_7.1.x86_64

<SNIP>
    CC       /tmp/build/perf/tests/llvm.o
  cc1: warnings being treated as errors
  tests/llvm.c: In function ‘test_llvm__fetch_bpf_obj’:
  tests/llvm.c:53: error: declaration of ‘index’ shadows a global declaration
  /usr/include/string.h:489: error: shadowed declaration is here
<SNIP>
    CC       /tmp/build/perf/tests/bpf.o
  cc1: warnings being treated as errors
  tests/bpf.c: In function ‘__test__bpf’:
  tests/bpf.c:149: error: declaration of ‘index’ shadows a global declaration
  /usr/include/string.h:489: error: shadowed declaration is here
<SNIP>

Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: pi3orama@163.com
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Fixes: b31de018a628 ("perf test: Enhance the LLVM test: update basic BPF test program")
Fixes: ba1fae431e74 ("perf test: Add 'perf test BPF'")
Link: http://lkml.kernel.org/n/tip-akpo4r750oya2phxoh9e3447@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/bpf.c

@@ -146,7 +146,7 @@ prepare_bpf(void *obj_buf, size_t obj_buf_sz, const char *name)
 	return obj;
 }
 
-static int __test__bpf(int index)
+static int __test__bpf(int idx)
 {
 	int ret;
 	void *obj_buf;
@@ -154,27 +154,27 @@ static int __test__bpf(int index)
 	struct bpf_object *obj;
 
 	ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
-				       bpf_testcase_table[index].prog_id,
+				       bpf_testcase_table[idx].prog_id,
 				       true);
 	if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
 		pr_debug("Unable to get BPF object, %s\n",
-			 bpf_testcase_table[index].msg_compile_fail);
-		if (index == 0)
+			 bpf_testcase_table[idx].msg_compile_fail);
+		if (idx == 0)
 			return TEST_SKIP;
 		else
 			return TEST_FAIL;
 	}
 
 	obj = prepare_bpf(obj_buf, obj_buf_sz,
-			  bpf_testcase_table[index].name);
+			  bpf_testcase_table[idx].name);
 	if (!obj) {
 		ret = TEST_FAIL;
 		goto out;
 	}
 
 	ret = do_test(obj,
-		      bpf_testcase_table[index].target_func,
-		      bpf_testcase_table[index].expect_result);
+		      bpf_testcase_table[idx].target_func,
+		      bpf_testcase_table[idx].expect_result);
 out:
 	bpf__clear();
 	return ret;

tools/perf/tests/llvm.c

@@ -50,7 +50,7 @@ static struct {
 int
 test_llvm__fetch_bpf_obj(void **p_obj_buf,
 			 size_t *p_obj_buf_sz,
-			 enum test_llvm__testcase index,
+			 enum test_llvm__testcase idx,
 			 bool force)
 {
 	const char *source;
@@ -59,11 +59,11 @@ test_llvm__fetch_bpf_obj(void **p_obj_buf,
 	char *tmpl_new = NULL, *clang_opt_new = NULL;
 	int err, old_verbose, ret = TEST_FAIL;
 
-	if (index >= __LLVM_TESTCASE_MAX)
+	if (idx >= __LLVM_TESTCASE_MAX)
 		return TEST_FAIL;
 
-	source = bpf_source_table[index].source;
-	desc = bpf_source_table[index].desc;
+	source = bpf_source_table[idx].source;
+	desc = bpf_source_table[idx].desc;
 
 	perf_config(perf_config_cb, NULL);