Re: [PATCH v1 1/4] perf report: Find the inline stack for a given address

Arnaldo Carvalho de Melo
2016-12-06T20:04:00Z

Em Tue, Nov 29, 2016 at 10:55:41PM +0800, Jin Yao escreveu:
> 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.
>
> The results (filename:line_nr) would be saved in a list and
> returned to the caller.

You're doing multiple things in this changeset, which makes reviewing
harder than it could be, so please consider breaking it in at least:

1. introduce dso_name_get() out of existing code and use it, renaming
it to dso__name(), as "_get()" is usually reserved for refcount
operations (see dso__get(), thread__get(), etc, for instance), just like
with the kernel sources.

2. introduce the inline_list thing and name the functions handling it
using that prefix, and as well separate the method name from the struct
name using __, as done elsewhere in tools/perf/, i.e. that function:

ilist_apend()

should be renamed to:

inline_list__append()

Better, follow the list_head model and instead call it:

inline_list__add_tail()

But as it also allocates space for the node, maybe inline_list__append()
is appropriate :-\

- Arnaldo

> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> ---
> tools/perf/util/srcline.c | 206 +++++++++++++++++++++++++++++++++++++++-------
> tools/perf/util/util.h | 15 ++++
> 2 files changed, 193 insertions(+), 28 deletions(-)
>
> diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
> index b4db3f4..0145625 100644
> --- a/tools/perf/util/srcline.c
> +++ b/tools/perf/util/srcline.c
> @@ -12,6 +12,39 @@
>
> bool srcline_full_filename;
>
> +static const char *dso_name_get(struct dso *dso)
> +{
> + const char *dso_name;
> +
> + if (dso->symsrc_filename)
> + dso_name = dso->symsrc_filename;
> + else
> + dso_name = dso->long_name;
> +
> + if (dso_name[0] == '[')
> + return NULL;
> +
> + if (!strncmp(dso_name, "/tmp/perf-", 10))
> + return NULL;
> +
> + return dso_name;
> +}
> +
> +static int ilist_apend(char *filename, int line_nr, struct inline_node *node)
> +{
> + struct inline_list *ilist;
> +
> + ilist = zalloc(sizeof(*ilist));
> + if (ilist == NULL)
> + return -1;
> +
> + ilist->filename = filename;
> + ilist->line_nr = line_nr;
> + list_add_tail(&ilist->list, &node->val);
> +
> + return 0;
> +}
> +
> #ifdef HAVE_LIBBFD_SUPPORT
>
> /*
> @@ -153,7 +186,7 @@ static void addr2line_cleanup(struct a2l_data *a2l)
>
> 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;
> @@ -178,8 +211,14 @@ 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 (ilist_apend(strdup(a2l->filename),
> + a2l->line, node) != 0)
> + return 0;
> + }
> + }
> }
>
> if (a2l->found && a2l->filename) {
> @@ -205,18 +244,68 @@ 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)) {
> + free_inline_node(node);
> + return NULL;
> + }
> +
> + if (list_empty(&node->val)) {
> + free_inline_node(node);
> + return NULL;
> + }
> +
> + return node;

Perhaps have:

out_free_inline_node:
inline_node__delete(node);
return NULL;

and jump to here in those two cases above? That after renaming
free_inline_node(node) to inline_node__delete(node) to follow
convention used in most parts of tools/perf/.

> +}
> +
> #else /* HAVE_LIBBFD_SUPPORT */
>
> +static int filename_split(const char *dso_name, char *filename,
> + unsigned int *line_nr)
> +{
> + char *sep;
> +
> + sep = strchr(filename, '\n');
> + if (sep)
> + *sep = '\0';
> +
> + if (!strcmp(filename, "??:0"))
> + return -1;
> +
> + sep = strchr(filename, ':');
> + if (sep) {
> + *sep++ = '\0';
> + *line_nr = strtoul(sep, NULL, 0);
> + }
> +
> + return 0;
> +}
> +
> 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];
> char *filename = NULL;
> size_t len;
> - char *sep;
> int ret = 0;
>
> scnprintf(cmd, sizeof(cmd), "addr2line -e %s %016"PRIx64,
> @@ -233,23 +322,14 @@ static int addr2line(const char *dso_name, u64 addr,
> goto out;
> }
>
> - sep = strchr(filename, '\n');
> - if (sep)
> - *sep = '\0';
> -
> - if (!strcmp(filename, "??:0")) {
> - pr_debug("no debugging info in %s\n", dso_name);
> + if (filename_split(dso_name, filename, line_nr) != 0) {
> free(filename);
> goto out;
> }
>
> - sep = strchr(filename, ':');
> - if (sep) {
> - *sep++ = '\0';
> - *file = filename;
> - *line_nr = strtoul(sep, NULL, 0);
> - ret = 1;
> - }
> + *file = filename;
> + ret = 1;
> +
> out:
> pclose(fp);
> return ret;
> @@ -259,6 +339,57 @@ 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_warn("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(dso_name, filename, &line_nr) != 0) {
> + free(filename);
> + goto out;
> + }
> +
> + if (ilist_apend(filename, line_nr, node) != 0)
> + goto out;
> +
> + filename = NULL;
> + }
> +
> +out:
> + pclose(fp);
> +
> + if (list_empty(&node->val)) {
> + free_inline_node(node);
> + return NULL;
> + }
> +
> + return node;
> +}
> +
> #endif /* HAVE_LIBBFD_SUPPORT */
>
> /*
> @@ -278,18 +409,11 @@ char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
> if (!dso->has_srcline)
> goto out;
>
> - if (dso->symsrc_filename)
> - dso_name = dso->symsrc_filename;
> - else
> - dso_name = dso->long_name;
> -
> - if (dso_name[0] == '[')
> - goto out;
> -
> - if (!strncmp(dso_name, "/tmp/perf-", 10))
> + dso_name = dso_name_get(dso);
> + 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",
> @@ -329,3 +453,29 @@ char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
> {
> return __get_srcline(dso, addr, sym, show_sym, false);
> }
> +
> +struct inline_node *get_inline_node(struct dso *dso, u64 addr)
> +{

Please rename this to dso__parse_addr_inlines().

> + const char *dso_name;
> +
> + dso_name = dso_name_get(dso);
> + if (dso_name == NULL)
> + return NULL;
> +
> + return addr2inlines(dso_name, addr, dso);
> +}
> +
> +void free_inline_node(struct inline_node *node)

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(&ilist->list);

list_del_init()

> + if (ilist->filename != NULL)
> + free(ilist->filename);
> +
> + free(ilist);
> + }
> +
> + free(node);
> +}
> diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
> index 79662d6..febe8d7 100644
> --- a/tools/perf/util/util.h
> +++ b/tools/perf/util/util.h
> @@ -78,6 +78,7 @@
> #include <termios.h>
> #include <linux/bitops.h>
> #include <termios.h>
> +#include <linux/list.h>
> #include "strlist.h"
>
> extern const char *graph_line;
> @@ -365,4 +366,18 @@ int is_printable_array(char *p, unsigned int len);
>
> int timestamp__scnprintf_usec(u64 timestamp, char *buf, size_t sz);
>
> +struct inline_list {
> + char *filename;
> + unsigned int line_nr;
> + struct list_head list;
> +};
> +
> +struct inline_node {
> + u64 addr;
> + struct list_head val;
> +};
> +
> +struct inline_node *get_inline_node(struct dso *dso, u64 addr);
> +void free_inline_node(struct inline_node *node);
> +
> #endif /* GIT_COMPAT_UTIL_H */
> --
> 2.7.4