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Subject[RFC 6/6] perf probe: Make it possible to add a C++ uprobe
Date
From: Holger Hans Peter Freyther <holgar+kernel@google.com>

If the linkage name looks like a common C++ ABI name use it instead of
the original function name. This makes adding a uprobe for a C++ symbol
possible.

./perf probe -x ./cxx-example "std::vector<int, std::allocator<int> >::at"
Added new event:
probe_foo:_ZNSt6vectorIiSaIiEE2atEm (on _ZN... in /cxx-example)

You can now use it in all perf tools, such as:

perf record -e probe_foo:_ZNSt6vectorIiSaIiEE2atEm -aR sleep 1

Signed-off-by: Holger Hans Peter Freyther <holgar+kernel@google.com>
---
tools/perf/util/probe-finder.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 4ba4b18..4cfa3de 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1317,6 +1317,7 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
struct perf_probe_point *pp = &pf->pev->point;
struct probe_trace_event *tev;
struct perf_probe_arg *args = NULL;
+ const char *linkage_name;
int ret, i;

/* Check number of tevs */
@@ -1333,6 +1334,16 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
if (ret < 0)
goto end;

+ /*
+ * Adding a C++ name like std::vector<int, std::allocator<int> >::at
+ * will fail. Check if we want to use the linkage name instead.
+ */
+ linkage_name = die_get_linkage_name(&pf->sp_die);
+ if (linkage_name && strncmp(linkage_name, "_Z", 2) == 0) {
+ free(pp->function);
+ pp->function = strdup(linkage_name);
+ }
+
tev->point.realname = strdup(dwarf_diename(sc_die));
if (!tev->point.realname) {
ret = -ENOMEM;
--
2.7.4
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