[PATCH v6 2/5] perf report: Find the inline stack for a given address

[Jin Yao]

It would be useful for perf to support a mode to query the inline stack
for a given callgraph address. This would simplify finding the right
code in code that does a lot of inlining.

The srcline.c has contained the code which supports to translate the
address to filename:line_nr. This patch just extends the function to let
it support getting the inline stacks.

It introduces the inline_list which will store the inline function
result (filename:line_nr and funcname).

If BFD lib is not supported, the result is only filename:line_nr.

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Tested-by: Milian Wolff <milian.wolff@xxxxxxxx>
---
 tools/perf/util/srcline.c        | 167 +++++++++++++++++++++++++++++++++++++--
 tools/perf/util/symbol-elf.c     |   5 ++
 tools/perf/util/symbol-minimal.c |   7 ++
 tools/perf/util/symbol.h         |   2 +
 tools/perf/util/util.h           |  16 ++++
 5 files changed, 192 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index 2953c9f..3ce28f7 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -7,6 +7,7 @@
 #include "util/dso.h"
 #include "util/util.h"
 #include "util/debug.h"
+#include "util/callchain.h"
 
 #include "symbol.h"
 
@@ -30,6 +31,34 @@ static const char *dso__name(struct dso *dso)
 	return dso_name;
 }
 
+static int inline_list__append(char *filename, char *funcname, int line_nr,
+			       struct inline_node *node, struct dso *dso)
+{
+	struct inline_list *ilist;
+	char *demangled;
+
+	ilist = zalloc(sizeof(*ilist));
+	if (ilist == NULL)
+		return -1;
+
+	ilist->filename = filename;
+	ilist->line_nr = line_nr;
+
+	if (dso != NULL) {
+		demangled = dso__demangle_sym(dso, 0, funcname);
+		if (demangled == NULL) {
+			ilist->funcname = funcname;
+		} else {
+			ilist->funcname = demangled;
+			free(funcname);
+		}
+	}
+
+	list_add_tail(&ilist->list, &node->val);
+
+	return 0;
+}
+
 #ifdef HAVE_LIBBFD_SUPPORT
 
 /*
@@ -169,9 +198,17 @@ static void addr2line_cleanup(struct a2l_data *a2l)
 
 #define MAX_INLINE_NEST 1024
 
+static void inline_list__reverse(struct inline_node *node)
+{
+	struct inline_list *ilist, *n;
+
+	list_for_each_entry_safe_reverse(ilist, n, &node->val, list)
+		list_move_tail(&ilist->list, &node->val);
+}
+
 static int addr2line(const char *dso_name, u64 addr,
 		     char **file, unsigned int *line, struct dso *dso,
-		     bool unwind_inlines)
+		     bool unwind_inlines, struct inline_node *node)
 {
 	int ret = 0;
 	struct a2l_data *a2l = dso->a2l;
@@ -196,8 +233,21 @@ static int addr2line(const char *dso_name, u64 addr,
 
 		while (bfd_find_inliner_info(a2l->abfd, &a2l->filename,
 					     &a2l->funcname, &a2l->line) &&
-		       cnt++ < MAX_INLINE_NEST)
-			;
+		       cnt++ < MAX_INLINE_NEST) {
+
+			if (node != NULL) {
+				if (inline_list__append(strdup(a2l->filename),
+							strdup(a2l->funcname),
+							a2l->line, node,
+							dso) != 0)
+					return 0;
+			}
+		}
+
+		if ((node != NULL) &&
+		    (callchain_param.order != ORDER_CALLEE)) {
+			inline_list__reverse(node);
+		}
 	}
 
 	if (a2l->found && a2l->filename) {
@@ -223,6 +273,35 @@ void dso__free_a2l(struct dso *dso)
 	dso->a2l = NULL;
 }
 
+static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
+	struct dso *dso)
+{
+	char *file = NULL;
+	unsigned int line = 0;
+	struct inline_node *node;
+
+	node = zalloc(sizeof(*node));
+	if (node == NULL) {
+		perror("not enough memory for the inline node");
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&node->val);
+	node->addr = addr;
+
+	if (!addr2line(dso_name, addr, &file, &line, dso, TRUE, node))
+		goto out_free_inline_node;
+
+	if (list_empty(&node->val))
+		goto out_free_inline_node;
+
+	return node;
+
+out_free_inline_node:
+	inline_node__delete(node);
+	return NULL;
+}
+
 #else /* HAVE_LIBBFD_SUPPORT */
 
 static int filename_split(char *filename, unsigned int *line_nr)
@@ -249,7 +328,8 @@ static int filename_split(char *filename, unsigned int *line_nr)
 static int addr2line(const char *dso_name, u64 addr,
 		     char **file, unsigned int *line_nr,
 		     struct dso *dso __maybe_unused,
-		     bool unwind_inlines __maybe_unused)
+		     bool unwind_inlines __maybe_unused,
+		     struct inline_node *node __maybe_unused)
 {
 	FILE *fp;
 	char cmd[PATH_MAX];
@@ -288,6 +368,58 @@ void dso__free_a2l(struct dso *dso __maybe_unused)
 {
 }
 
+static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
+	struct dso *dso __maybe_unused)
+{
+	FILE *fp;
+	char cmd[PATH_MAX];
+	struct inline_node *node;
+	char *filename = NULL;
+	size_t len;
+	unsigned int line_nr = 0;
+
+	scnprintf(cmd, sizeof(cmd), "addr2line -e %s -i %016"PRIx64,
+		  dso_name, addr);
+
+	fp = popen(cmd, "r");
+	if (fp == NULL) {
+		pr_err("popen failed for %s\n", dso_name);
+		return NULL;
+	}
+
+	node = zalloc(sizeof(*node));
+	if (node == NULL) {
+		perror("not enough memory for the inline node");
+		goto out;
+	}
+
+	INIT_LIST_HEAD(&node->val);
+	node->addr = addr;
+
+	while (getline(&filename, &len, fp) != -1) {
+		if (filename_split(filename, &line_nr) != 1) {
+			free(filename);
+			goto out;
+		}
+
+		if (inline_list__append(filename, NULL, line_nr, node,
+					NULL) != 0)
+			goto out;
+
+		filename = NULL;
+	}
+
+out:
+	pclose(fp);
+
+	if (list_empty(&node->val)) {
+		inline_node__delete(node);
+		return NULL;
+	}
+
+	return node;
+}
+
 #endif /* HAVE_LIBBFD_SUPPORT */
 
 /*
@@ -311,7 +443,7 @@ char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 	if (dso_name == NULL)
 		goto out;
 
-	if (!addr2line(dso_name, addr, &file, &line, dso, unwind_inlines))
+	if (!addr2line(dso_name, addr, &file, &line, dso, unwind_inlines, NULL))
 		goto out;
 
 	if (asprintf(&srcline, "%s:%u",
@@ -351,3 +483,28 @@ char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 {
 	return __get_srcline(dso, addr, sym, show_sym, false);
 }
+
+struct inline_node *dso__parse_addr_inlines(struct dso *dso, u64 addr)
+{
+	const char *dso_name;
+
+	dso_name = dso__name(dso);
+	if (dso_name == NULL)
+		return NULL;
+
+	return addr2inlines(dso_name, addr, dso);
+}
+
+void inline_node__delete(struct inline_node *node)
+{
+	struct inline_list *ilist, *tmp;
+
+	list_for_each_entry_safe(ilist, tmp, &node->val, list) {
+		list_del_init(&ilist->list);
+		zfree(&ilist->filename);
+		zfree(&ilist->funcname);
+		free(ilist);
+	}
+
+	free(node);
+}
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 0e660db..d1a40bb 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -390,6 +390,11 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *
 	return 0;
 }
 
+char *dso__demangle_sym(struct dso *dso, int kmodule, char *elf_name)
+{
+	return demangle_sym(dso, kmodule, elf_name);
+}
+
 /*
  * Align offset to 4 bytes as needed for note name and descriptor data.
  */
diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c
index 11cdde9..870ef0f 100644
--- a/tools/perf/util/symbol-minimal.c
+++ b/tools/perf/util/symbol-minimal.c
@@ -373,3 +373,10 @@ int kcore_copy(const char *from_dir __maybe_unused,
 void symbol__elf_init(void)
 {
 }
+
+char *dso__demangle_sym(struct dso *dso __maybe_unused,
+			int kmodule __maybe_unused,
+			char *elf_name __maybe_unused)
+{
+	return NULL;
+}
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 9222c7e..e36213c 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -305,6 +305,8 @@ int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss,
 				struct map *map);
 
+char *dso__demangle_sym(struct dso *dso, int kmodule, char *elf_name);
+
 void __symbols__insert(struct rb_root *symbols, struct symbol *sym, bool kernel);
 void symbols__insert(struct rb_root *symbols, struct symbol *sym);
 void symbols__fixup_duplicate(struct rb_root *symbols);
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index b2cfa47..cc0700d 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -364,4 +364,20 @@ int is_printable_array(char *p, unsigned int len);
 int timestamp__scnprintf_usec(u64 timestamp, char *buf, size_t sz);
 
 int unit_number__scnprintf(char *buf, size_t size, u64 n);
+
+struct inline_list {
+	char			*filename;
+	char			*funcname;
+	unsigned int		line_nr;
+	struct list_head	list;
+};
+
+struct inline_node {
+	u64			addr;
+	struct list_head	val;
+};
+
+struct inline_node *dso__parse_addr_inlines(struct dso *dso, u64 addr);
+void inline_node__delete(struct inline_node *node);
+
 #endif /* GIT_COMPAT_UTIL_H */
-- 
2.7.4