perf probe: Fix --line to handle aliased symbols in glibc

Fix perf probe --line to handle aliased symbols correctly in glibc.

This makes line_range search failing back to address-based alternative
search as same as --add and --vars.

Without this patch;
  -----
  # ./perf probe -x /usr/lib64/libc-2.17.so -L malloc
  Specified source line is not found.
    Error: Failed to show lines.
  -----

With this patch;
  -----
  # ./perf probe -x /usr/lib64/libc-2.17.so -L malloc
  <__libc_malloc@/usr/src/debug/glibc-2.17-c758a686/malloc/malloc.c:0>
        0  __libc_malloc(size_t bytes)
        1  {
             mstate ar_ptr;
             void *victim;

             __malloc_ptr_t (*hook) (size_t, const __malloc_ptr_t)
        6      = force_reg (__malloc_hook);
        7    if (__builtin_expect (hook != NULL, 0))
        8      return (*hook)(bytes, RETURN_ADDRESS (0));

       10    arena_lookup(ar_ptr);

       12    arena_lock(ar_ptr, bytes);
  -----

Note that this actually shows __libc_malloc, since it is the real
instance of malloc. User can use both __libc_malloc and malloc for
--line.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150306073122.6904.18540.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index b8f4578..4cfd121 100644 (file)
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -353,6 +353,31 @@ static int get_alternative_probe_event(struct debuginfo *dinfo,
        return ret;
 }
 
+static int get_alternative_line_range(struct debuginfo *dinfo,
+                                     struct line_range *lr,
+                                     const char *target, bool user)
+{
+       struct perf_probe_point pp = { 0 }, result = { 0 };
+       int ret, len = 0;
+
+       pp.function = lr->function;
+       pp.file = lr->file;
+       pp.line = lr->start;
+       if (lr->end != INT_MAX)
+               len = lr->end - lr->start;
+       ret = find_alternative_probe_point(dinfo, &pp, &result,
+                                          target, user);
+       if (!ret) {
+               lr->function = result.function;
+               lr->file = result.file;
+               lr->start = result.line;
+               if (lr->end != INT_MAX)
+                       lr->end = lr->start + len;
+               clear_perf_probe_point(&pp);
+       }
+       return ret;
+}
+
 /* Open new debuginfo of given module */
 static struct debuginfo *open_debuginfo(const char *module, bool silent)
 {
@@ -734,7 +759,8 @@ static int _show_one_line(FILE *fp, int l, bool skip, bool show_num)
  * Show line-range always requires debuginfo to find source file and
  * line number.
  */
-static int __show_line_range(struct line_range *lr, const char *module)
+static int __show_line_range(struct line_range *lr, const char *module,
+                            bool user)
 {
        int l = 1;
        struct int_node *ln;
@@ -750,6 +776,11 @@ static int __show_line_range(struct line_range *lr, const char *module)
                return -ENOENT;
 
        ret = debuginfo__find_line_range(dinfo, lr);
+       if (!ret) {     /* Not found, retry with an alternative */
+               ret = get_alternative_line_range(dinfo, lr, module, user);
+               if (!ret)
+                       ret = debuginfo__find_line_range(dinfo, lr);
+       }
        debuginfo__delete(dinfo);
        if (ret == 0 || ret == -ENOENT) {
                pr_warning("Specified source line is not found.\n");
@@ -819,7 +850,7 @@ int show_line_range(struct line_range *lr, const char *module, bool user)
        ret = init_symbol_maps(user);
        if (ret < 0)
                return ret;
-       ret = __show_line_range(lr, module);
+       ret = __show_line_range(lr, module, user);
        exit_symbol_maps();
 
        return ret;