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Date: Mon, 14 May 2018 12:19:37 +0800
From: Holger Freyther <automatic+kernel@...yther.de>
To: linux-kernel@...r.kernel.org
Cc: Holger Hans Peter Freyther <holgar+kernel@...gle.com>
Subject: [RFC 3/6] perf probe: Make listing of C++ functions work
From: Holger Hans Peter Freyther <holgar+kernel@...gle.com>
If die_match_name does not match, attempt to demangle the linkage name.
To use the generic demangling API we require to have a struct dso. Store
it inside the debuginfo and pass it to the relevant callbacks.
./perf probe -x ./foo -L \
"std::vector<int, std::allocator<int> >::at:2-3"
<...::at@...r/include/c++/5/bits/stl_vector.h:2>
2 _M_range_check(__n);
3 return (*this)[__n];
Signed-off-by: Holger Hans Peter Freyther <holgar+kernel@...gle.com>
---
tools/perf/util/probe-finder.c | 55 ++++++++++++++++++++++++++++++++++--------
tools/perf/util/probe-finder.h | 3 +++
2 files changed, 48 insertions(+), 10 deletions(-)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c37fbef..c73dccc 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -96,7 +96,7 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
return -ENOENT;
}
-static struct debuginfo *__debuginfo__new(const char *path)
+static struct debuginfo *__debuginfo__new(const char *path, struct dso *dso)
{
struct debuginfo *dbg = zalloc(sizeof(*dbg));
if (!dbg)
@@ -104,8 +104,10 @@ static struct debuginfo *__debuginfo__new(const char *path)
if (debuginfo__init_offline_dwarf(dbg, path) < 0)
zfree(&dbg);
- if (dbg)
+ if (dbg) {
pr_debug("Open Debuginfo file: %s\n", path);
+ dbg->dso = dso__get(dso);
+ }
return dbg;
}
@@ -135,13 +137,15 @@ struct debuginfo *debuginfo__new(const char *path)
if (dso__read_binary_type_filename(dso, *type, &nil,
buf, PATH_MAX) < 0)
continue;
- dinfo = __debuginfo__new(buf);
+ dinfo = __debuginfo__new(buf, dso);
}
- dso__put(dso);
out:
/* if failed to open all distro debuginfo, open given binary */
- return dinfo ? : __debuginfo__new(path);
+ if (!dinfo)
+ dinfo = __debuginfo__new(path, dso);
+ dso__put(dso);
+ return dinfo;
}
void debuginfo__delete(struct debuginfo *dbg)
@@ -149,6 +153,7 @@ void debuginfo__delete(struct debuginfo *dbg)
if (dbg) {
if (dbg->dwfl)
dwfl_end(dbg->dwfl);
+ dso__put(dbg->dso);
free(dbg);
}
}
@@ -167,6 +172,32 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
}
/*
+ * Check if the the demangled linkage_name matches the function. E.g. the
+ * linkage name of _ZNKSt6vectorIiSaIiEE4sizeEv matching the c++ function name
+ * of std::vector<int, std::allocator<int> >::size() const.
+ */
+static bool matches_demangled(struct debuginfo *dbg, Dwarf_Die *dw_die,
+ const char *function)
+{
+ const char *name;
+ char *demangled;
+ bool res;
+
+ name = die_get_linkage_name(dw_die);
+ if (!name)
+ return false;
+
+ demangled = dso__demangle_sym(dbg->dso, 0, name);
+ if (!demangled)
+ return false;
+
+ res = strglobmatch(demangled, function);
+ free(demangled);
+ return res;
+}
+
+
+/*
* Convert a location into trace_arg.
* If tvar == NULL, this just checks variable can be converted.
* If fentry == true and vr_die is a parameter, do huristic search
@@ -975,6 +1006,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
struct dwarf_callback_param {
void *data;
int retval;
+ struct debuginfo *dbg;
};
/* Search function from function name */
@@ -1721,7 +1753,8 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
return DWARF_CB_OK;
if (die_is_func_def(sp_die) &&
- die_match_name(sp_die, lr->function)) {
+ (die_match_name(sp_die, lr->function) ||
+ matches_demangled(param->dbg, sp_die, lr->function))) {
lf->fname = dwarf_decl_file(sp_die);
dwarf_decl_line(sp_die, &lr->offset);
pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
@@ -1744,9 +1777,11 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
return DWARF_CB_OK;
}
-static int find_line_range_by_func(struct line_finder *lf)
+static int find_line_range_by_func(struct debuginfo *dbg,
+ struct line_finder *lf)
{
- struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
+ struct dwarf_callback_param param = {
+ .data = (void *)lf, .retval = 0, .dbg = dbg};
dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
return param.retval;
}
@@ -1766,7 +1801,7 @@ int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
.function = lr->function, .file = lr->file,
.cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
struct dwarf_callback_param line_range_param = {
- .data = (void *)&lf, .retval = 0};
+ .data = (void *)&lf, .retval = 0, .dbg = dbg};
dwarf_getpubnames(dbg->dbg, pubname_search_cb,
&pubname_param, 0);
@@ -1796,7 +1831,7 @@ int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
if (!lr->file || lf.fname) {
if (lr->function)
- ret = find_line_range_by_func(&lf);
+ ret = find_line_range_by_func(dbg, &lf);
else {
lf.lno_s = lr->start;
lf.lno_e = lr->end;
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 1625298..e28acbd 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -14,6 +14,8 @@
#define PROBE_ARG_VARS "$vars"
#define PROBE_ARG_PARAMS "$params"
+struct dso;
+
static inline int is_c_varname(const char *name)
{
/* TODO */
@@ -32,6 +34,7 @@ struct debuginfo {
Dwfl_Module *mod;
Dwfl *dwfl;
Dwarf_Addr bias;
+ struct dso *dso;
};
/* This also tries to open distro debuginfo */
--
2.7.4
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