[tip:perf/core] perf srcline: Show correct function name for srcline of callchains

[tip-bot for Namhyung Kim]

Commit-ID:  7285cf3325b4a1dfb336d31eebc27dfbc30fb9aa
Gitweb:     https://git.kernel.org/tip/7285cf3325b4a1dfb336d31eebc27dfbc30fb9aa
Author:     Namhyung Kim <namhyung@xxxxxxxxxx>
AuthorDate: Tue, 31 Oct 2017 11:06:54 +0900
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 1 Nov 2017 11:44:38 -0300

perf srcline: Show correct function name for srcline of callchains

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 an 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

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Reviewed-by: Milian Wolff <milian.wolff@xxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: kernel-team@xxxxxxx
Link: http://lkml.kernel.org/r/20171031020654.31163-2-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@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 51dc49c..ad1b46f 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;
 }