[tip: perf/core] perf probe: Fix to find range-only function instance

[tip-bot2 for Masami Hiramatsu]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     b77afa1f810f37bd8a36cb1318178dfe2d7af6b6
Gitweb:        https://git.kernel.org/tip/b77afa1f810f37bd8a36cb1318178dfe2d7af6b6
Author:        Masami Hiramatsu <mhiramat@xxxxxxxxxx>
AuthorDate:    Thu, 24 Oct 2019 18:12:36 +09:00
Committer:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Wed, 06 Nov 2019 15:43:05 -03:00

perf probe: Fix to find range-only function instance

Fix die_is_func_instance() to find range-only function instance.

In some case, a function instance can be made without any low PC or
entry PC, but only with address ranges by optimization.  (e.g. cold text
partially in "text.unlikely" section) To find such function instance, we
have to check the range attribute too.

Fixes: e1ecbbc3fa83 ("perf probe: Fix to handle optimized not-inlined functions")
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/157190835669.1859.8368628035930950596.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/dwarf-aux.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index df6cee5..2ec24c3 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -318,10 +318,14 @@ bool die_is_func_def(Dwarf_Die *dw_die)
 bool die_is_func_instance(Dwarf_Die *dw_die)
 {
 	Dwarf_Addr tmp;
+	Dwarf_Attribute attr_mem;
 
 	/* Actually gcc optimizes non-inline as like as inlined */
-	return !dwarf_func_inline(dw_die) && dwarf_entrypc(dw_die, &tmp) == 0;
+	return !dwarf_func_inline(dw_die) &&
+	       (dwarf_entrypc(dw_die, &tmp) == 0 ||
+		dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL);
 }
+
 /**
  * die_get_data_member_location - Get the data-member offset
  * @mb_die: a DIE of a member of a data structure