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authorMasami Hiramatsu <mhiramat@kernel.org>2016-09-24 00:35:31 +0900
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-09-29 11:17:08 -0300
commitd5a00296a63fdd049273f86d0a0cdef6b230f8e6 (patch)
treef1020d6a3eaa93d89c26dd0efee69c358bb5e04e
parent35726d3a4ca9ce10811032baf6fa0b3529aac087 (diff)
downloadop-kernel-dev-d5a00296a63fdd049273f86d0a0cdef6b230f8e6.zip
op-kernel-dev-d5a00296a63fdd049273f86d0a0cdef6b230f8e6.tar.gz
perf probe: Match linkage name with mangled name
Match linkage name with mangled name if exists. The linkage_name is used for storing mangled name of the object. Thus, this allows 'perf probe' to find appropriate probe point from mangled symbol as below. E.g. without this fix: ---- $ perf probe -x /usr/lib64/libstdc++.so.6 \ -D _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv Probe point '_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv' not found. Error: Failed to add events. ---- With this fix, perf probe can find the correct one. ---- $ perf probe -x /usr/lib64/libstdc++.so.6 \ -D _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv p:probe_libstdc/_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv /usr/lib64/libstdc++.so.6.0.22:0x8ca60 ---- Committer notes: After the fix, setting it for real (no -D/--definition, that amounts to a --dry-run): # perf probe -x /usr/lib64/libstdc++.so.6 _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv Added new event: probe_libstdc:_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv (on _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv in /usr/lib64/libstdc++.so.6.0.22) You can now use it in all perf tools, such as: perf record -e probe_libstdc:_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv -aR sleep 1 # perf probe -l probe_libstdc:* probe_libstdc:_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv (on is_open@libstdc++-v3/include/fstream in /usr/lib64/libstdc++.so.6.0.22) # Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Jiri Olsa <jolsa@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/147464493162.29804.16715053505069382443.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/util/dwarf-aux.c28
-rw-r--r--tools/perf/util/dwarf-aux.h3
2 files changed, 29 insertions, 2 deletions
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index faec899..41e068e 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -130,6 +130,22 @@ int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
}
/**
+ * die_get_linkage_name - Get the linkage name of the object
+ * @dw_die: A DIE of the object
+ *
+ * Get the linkage name attiribute of given @dw_die.
+ * For C++ binary, the linkage name will be the mangled symbol.
+ */
+const char *die_get_linkage_name(Dwarf_Die *dw_die)
+{
+ Dwarf_Attribute attr;
+
+ if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
+ return NULL;
+ return dwarf_formstring(&attr);
+}
+
+/**
* die_compare_name - Compare diename and tname
* @dw_die: a DIE
* @tname: a string of target name
@@ -145,18 +161,26 @@ bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
}
/**
- * die_match_name - Match diename and glob
+ * die_match_name - Match diename/linkage name and glob
* @dw_die: a DIE
* @glob: a string of target glob pattern
*
* Glob matching the name of @dw_die and @glob. Return false if matching fail.
+ * This also match linkage name.
*/
bool die_match_name(Dwarf_Die *dw_die, const char *glob)
{
const char *name;
name = dwarf_diename(dw_die);
- return name ? strglobmatch(name, glob) : false;
+ if (name && strglobmatch(name, glob))
+ return true;
+ /* fall back to check linkage name */
+ name = die_get_linkage_name(dw_die);
+ if (name && strglobmatch(name, glob))
+ return true;
+
+ return false;
}
/**
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index 8b6d2f8..8ac53bf 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -38,6 +38,9 @@ int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr,
int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
int (*callback)(Dwarf_Die *, void *), void *data);
+/* Get DW_AT_linkage_name (should be NULL for C binary) */
+const char *die_get_linkage_name(Dwarf_Die *dw_die);
+
/* Ensure that this DIE is a subprogram and definition (not declaration) */
bool die_is_func_def(Dwarf_Die *dw_die);
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