[PATCH 2/2] perf tools: Show correct function name for srcline of callchains

From: Namhyung Kim
Date: Mon Oct 30 2017 - 22:07:25 EST


When libbfd is not used, it doesn't show proper function name and reuse
the original symbol of the sample. That's because it passes the
original sym to inline_list__append(). As `addr2line -f` returns
function names as well, use that to create ad inline_sym and pass it to
inline_list__append().

For example, following data shows that inlined entries of main have same
name (main).

Before:
$ perf report -g srcline -q | head
45.22% inlining libm-2.26.so [.] __hypot_finite
|
---__hypot_finite ??:0
|
|--44.15%--hypot ??:0
| main complex:589
| main complex:597
| main complex:654
| main complex:664
| main inlining.cpp:14

After:
$ perf report -g srcline -q | head
45.22% inlining libm-2.26.so [.] __hypot_finite
|
---__hypot_finite
|
|--44.15%--hypot
| std::__complex_abs complex:589 (inlined)
| std::abs<double> complex:597 (inlined)
| std::_Norm_helper<true>::_S_do_it<double> complex:654 (inlined)
| std::norm<double> complex:664 (inlined)
| main inlining.cpp:14

Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Cc: Milian Wolff <milian.wolff@xxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/util/srcline.c | 95 +++++++++++++++++++++++++++--------------------
1 file changed, 55 insertions(+), 40 deletions(-)

diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index 51dc49c65476..ad1b46f1f2cf 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -10,7 +10,7 @@
#include "util/debug.h"
#include "util/callchain.h"
#include "srcline.h"
-
+#include "string2.h"
#include "symbol.h"

bool srcline_full_filename;
@@ -77,6 +77,41 @@ static char *srcline_from_fileline(const char *file, unsigned int line)
return srcline;
}

+static struct symbol *new_inline_sym(struct dso *dso,
+ struct symbol *base_sym,
+ const char *funcname)
+{
+ struct symbol *inline_sym;
+ char *demangled = NULL;
+
+ if (dso) {
+ demangled = dso__demangle_sym(dso, 0, funcname);
+ if (demangled)
+ funcname = demangled;
+ }
+
+ if (base_sym && strcmp(funcname, base_sym->name) == 0) {
+ /* reuse the real, existing symbol */
+ inline_sym = base_sym;
+ /* ensure that we don't alias an inlined symbol, which could
+ * lead to double frees in inline_node__delete
+ */
+ assert(!base_sym->inlined);
+ } else {
+ /* create a fake symbol for the inline frame */
+ inline_sym = symbol__new(base_sym ? base_sym->start : 0,
+ base_sym ? base_sym->end : 0,
+ base_sym ? base_sym->binding : 0,
+ funcname);
+ if (inline_sym)
+ inline_sym->inlined = 1;
+ }
+
+ free(demangled);
+
+ return inline_sym;
+}
+
#ifdef HAVE_LIBBFD_SUPPORT

/*
@@ -219,41 +254,6 @@ static void addr2line_cleanup(struct a2l_data *a2l)

#define MAX_INLINE_NEST 1024

-static struct symbol *new_inline_sym(struct dso *dso,
- struct symbol *base_sym,
- const char *funcname)
-{
- struct symbol *inline_sym;
- char *demangled = NULL;
-
- if (dso) {
- demangled = dso__demangle_sym(dso, 0, funcname);
- if (demangled)
- funcname = demangled;
- }
-
- if (base_sym && strcmp(funcname, base_sym->name) == 0) {
- /* reuse the real, existing symbol */
- inline_sym = base_sym;
- /* ensure that we don't alias an inlined symbol, which could
- * lead to double frees in inline_node__delete
- */
- assert(!base_sym->inlined);
- } else {
- /* create a fake symbol for the inline frame */
- inline_sym = symbol__new(base_sym ? base_sym->start : 0,
- base_sym ? base_sym->end : 0,
- base_sym ? base_sym->binding : 0,
- funcname);
- if (inline_sym)
- inline_sym->inlined = 1;
- }
-
- free(demangled);
-
- return inline_sym;
-}
-
static int inline_list__append_dso_a2l(struct dso *dso,
struct inline_node *node,
struct symbol *sym)
@@ -432,10 +432,11 @@ static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
char cmd[PATH_MAX];
struct inline_node *node;
char *filename = NULL;
- size_t len;
+ char *funcname = NULL;
+ size_t filelen, funclen;
unsigned int line_nr = 0;

- scnprintf(cmd, sizeof(cmd), "addr2line -e %s -i %016"PRIx64,
+ scnprintf(cmd, sizeof(cmd), "addr2line -e %s -i -f %016"PRIx64,
dso_name, addr);

fp = popen(cmd, "r");
@@ -453,20 +454,34 @@ static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
INIT_LIST_HEAD(&node->val);
node->addr = addr;

- while (getline(&filename, &len, fp) != -1) {
+ /* addr2line -f generates two lines for each inlined functions */
+ while (getline(&funcname, &funclen, fp) != -1) {
char *srcline;
+ struct symbol *inline_sym;
+
+ rtrim(funcname);
+
+ if (getline(&filename, &filelen, fp) == -1)
+ goto out;

if (filename_split(filename, &line_nr) != 1)
goto out;

srcline = srcline_from_fileline(filename, line_nr);
- if (inline_list__append(sym, srcline, node) != 0)
+ inline_sym = new_inline_sym(dso, sym, funcname);
+
+ if (inline_list__append(inline_sym, srcline, node) != 0) {
+ free(srcline);
+ if (inline_sym && inline_sym->inlined)
+ symbol__delete(inline_sym);
goto out;
+ }
}

out:
pclose(fp);
free(filename);
+ free(funcname);

return node;
}
--
2.14.3