perf probe: List probes with line number and file name

Improve --list to show current exist probes with line number and
file name. This enables user easily to check which line is
already probed.

for example:

 ./perf probe --list
 probe:vfs_read       (on vfs_read:8@linux-2.6-tip/fs/read_write.c)

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220619.32050.48702.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 116 insertions, 13 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index b44ddfb030d7..4e3c1aea7892 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -70,7 +70,6 @@ static int e_snprintf(char *str, size_t size, const char *format, ...)
         return ret;
 }
 
-
 static struct map_groups kmap_groups;
 static struct map *kmaps[MAP__NR_TYPES];
 
@@ -357,27 +356,39 @@ void parse_kprobe_trace_command(const char *cmd, struct kprobe_trace_event *tev)
 /* Compose only probe point (not argument) */
 static char *synthesize_perf_probe_point(struct perf_probe_point *pp)
 {
-        char *buf;
-        char offs[64] = "", line[64] = "";
-        int ret;
+        char *buf, *tmp;
+        char offs[32] = "", line[32] = "", file[32] = "";
+        int ret, len;
 
         buf = xzalloc(MAX_CMDLEN);
         if (pp->offset) {
-                ret = e_snprintf(offs, 64, "+%lu", pp->offset);
+                ret = e_snprintf(offs, 32, "+%lu", pp->offset);
                 if (ret <= 0)
                         goto error;
         }
         if (pp->line) {
-                ret = e_snprintf(line, 64, ":%d", pp->line);
+                ret = e_snprintf(line, 32, ":%d", pp->line);
+                if (ret <= 0)
+                        goto error;
+        }
+        if (pp->file) {
+                len = strlen(pp->file) - 32;
+                if (len < 0)
+                        len = 0;
+                tmp = strchr(pp->file + len, '/');
+                if (!tmp)
+                        tmp = pp->file + len - 1;
+                ret = e_snprintf(file, 32, "@%s", tmp + 1);
                 if (ret <= 0)
                         goto error;
         }
 
         if (pp->function)
-                ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
-                                 offs, pp->retprobe ? "%return" : "", line);
+                ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s%s", pp->function,
+                                 offs, pp->retprobe ? "%return" : "", line,
+                                 file);
         else
-                ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", pp->file, line);
+                ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", file, line);
         if (ret <= 0)
                 goto error;
 
@@ -511,15 +522,32 @@ void convert_to_perf_probe_event(struct kprobe_trace_event *tev,
 {
         char buf[64];
         int i;
+#ifndef NO_DWARF_SUPPORT
+        struct symbol *sym;
+        int fd, ret = 0;
 
-        pev->event = xstrdup(tev->event);
-        pev->group = xstrdup(tev->group);
-
+        sym = map__find_symbol_by_name(kmaps[MAP__FUNCTION],
+                                       tev->point.symbol, NULL);
+        if (sym) {
+                fd = open_vmlinux();
+                ret = find_perf_probe_point(fd, sym->start + tev->point.offset,
+                                            &pev->point);
+                close(fd);
+        }
+        if (ret <= 0) {
+                pev->point.function = xstrdup(tev->point.symbol);
+                pev->point.offset = tev->point.offset;
+        }
+#else
         /* Convert trace_point to probe_point */
         pev->point.function = xstrdup(tev->point.symbol);
         pev->point.offset = tev->point.offset;
+#endif
         pev->point.retprobe = tev->point.retprobe;
 
+        pev->event = xstrdup(tev->event);
+        pev->group = xstrdup(tev->group);
+
         /* Convert trace_arg to probe_arg */
         pev->nargs = tev->nargs;
         pev->args = xzalloc(sizeof(struct perf_probe_arg) * pev->nargs);
@@ -650,7 +678,7 @@ static void show_perf_probe_event(struct perf_probe_event *pev)
         ret = e_snprintf(buf, 128, "%s:%s", pev->group, pev->event);
         if (ret < 0)
                 die("Failed to copy event: %s", strerror(-ret));
-        printf("  %-40s (on %s", buf, place);
+        printf("  %-20s (on %s", buf, place);
 
         if (pev->nargs > 0) {
                 printf(" with");
@@ -671,6 +699,7 @@ void show_perf_probe_events(void)
         struct str_node *ent;
 
         setup_pager();
+        init_vmlinux();
 
         memset(&tev, 0, sizeof(tev));
         memset(&pev, 0, sizeof(pev));
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 251b4c49653e..e02b60770485 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -693,6 +693,76 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
         return pf.ntevs;
 }
 
+/* Reverse search */
+int find_perf_probe_point(int fd, unsigned long addr,
+                          struct perf_probe_point *ppt)
+{
+        Dwarf_Die cudie, spdie, indie;
+        Dwarf *dbg;
+        Dwarf_Line *line;
+        Dwarf_Addr laddr, eaddr;
+        const char *tmp;
+        int lineno, ret = 0;
+
+        dbg = dwarf_begin(fd, DWARF_C_READ);
+        if (!dbg)
+                return -ENOENT;
+
+        /* Find cu die */
+        if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie))
+                return -EINVAL;
+
+        /* Find a corresponding line */
+        line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
+        if (line) {
+                dwarf_lineaddr(line, &laddr);
+                if ((Dwarf_Addr)addr == laddr) {
+                        dwarf_lineno(line, &lineno);
+                        ppt->line = lineno;
+
+                        tmp = dwarf_linesrc(line, NULL, NULL);
+                        DIE_IF(!tmp);
+                        ppt->file = xstrdup(tmp);
+                        ret = 1;
+                }
+        }
+
+        /* Find a corresponding function */
+        if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
+                tmp = dwarf_diename(&spdie);
+                if (!tmp)
+                        goto end;
+
+                dwarf_entrypc(&spdie, &eaddr);
+                if (!lineno) {
+                        /* We don't have a line number, let's use offset */
+                        ppt->function = xstrdup(tmp);
+                        ppt->offset = addr - (unsigned long)eaddr;
+                        ret = 1;
+                        goto end;
+                }
+                if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr, &indie)) {
+                        /* addr in an inline function */
+                        tmp = dwarf_diename(&indie);
+                        if (!tmp)
+                                goto end;
+                        dwarf_decl_line(&indie, &lineno);
+                } else {
+                        if (eaddr == addr)      /* No offset: function entry */
+                                lineno = ppt->line;
+                        else
+                                dwarf_decl_line(&spdie, &lineno);
+                }
+                ppt->function = xstrdup(tmp);
+                ppt->line -= lineno;    /* Make a relative line number */
+        }
+
+end:
+        dwarf_end(dbg);
+        return ret;
+}
+
+
 /* Find line range from its line number */
 static void find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
 {
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 494952619b9c..2f2307d4139f 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -20,6 +20,10 @@ static inline int is_c_varname(const char *name)
 extern int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
                                     struct kprobe_trace_event **tevs);
 
+/* Find a perf_probe_point from debuginfo */
+extern int find_perf_probe_point(int fd, unsigned long addr,
+                                 struct perf_probe_point *ppt);
+
 extern int find_line_range(int fd, struct line_range *lr);
 
 #include <dwarf.h>