perf data: Fix duplicate field names and avoid reserved keywords

Some parameters of syscall tracepoints named as 'nr', 'event', etc.
When dealing with them, perf convert to ctf meets some problem:

 1. If a parameter with name 'nr', it will duplicate syscall's
    common field 'nr'. One such syscall is io_submit().

 2. If a parameter with name 'event', it is denied to be inserted
    because 'event' is a CTF spec keyword[1]. One such syscall is
    epoll_ctl.

This patch appends '_dupl_X' suffix to avoid problem 1, prepend a '_'
prefix to avoid problem 2.

[1] http://diamon.org/docs/ctf/v1.8.2/#specC.1.2

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jgalar@efficios.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
Link: http://lkml.kernel.org/r/1429372220-6406-7-git-send-email-jolsa@kernel.org
[ changed to use format_file::alias ]
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index b35c8d6c291d84c543ab29691d415d160f62cdf8..8eda4ed628e758c4858f249522716b67f5a1412b 100644 (file)
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -14,6 +14,7 @@
 #include <babeltrace/ctf-writer/event.h>
 #include <babeltrace/ctf-writer/event-types.h>
 #include <babeltrace/ctf-writer/event-fields.h>
+#include <babeltrace/ctf-ir/utils.h>
 #include <babeltrace/ctf/events.h>
 #include <traceevent/event-parse.h>
 #include "asm/bug.h"
@@ -184,6 +185,7 @@ static int add_tracepoint_field_value(struct ctf_writer *cw,
        unsigned int len;
        int ret;
 
+       name = fmtf->alias;
        offset = fmtf->offset;
        len = fmtf->size;
        if (flags & FIELD_IS_STRING)
@@ -567,6 +569,82 @@ static int process_sample_event(struct perf_tool *tool,
        return cs ? 0 : -1;
 }
 
+/* If dup < 0, add a prefix. Else, add _dupl_X suffix. */
+static char *change_name(char *name, char *orig_name, int dup)
+{
+       char *new_name = NULL;
+       size_t len;
+
+       if (!name)
+               name = orig_name;
+
+       if (dup >= 10)
+               goto out;
+       /*
+        * Add '_' prefix to potential keywork.  According to
+        * Mathieu Desnoyers (https://lkml.org/lkml/2015/1/23/652),
+        * futher CTF spec updating may require us to use '$'.
+        */
+       if (dup < 0)
+               len = strlen(name) + sizeof("_");
+       else
+               len = strlen(orig_name) + sizeof("_dupl_X");
+
+       new_name = malloc(len);
+       if (!new_name)
+               goto out;
+
+       if (dup < 0)
+               snprintf(new_name, len, "_%s", name);
+       else
+               snprintf(new_name, len, "%s_dupl_%d", orig_name, dup);
+
+out:
+       if (name != orig_name)
+               free(name);
+       return new_name;
+}
+
+static int event_class_add_field(struct bt_ctf_event_class *event_class,
+               struct bt_ctf_field_type *type,
+               struct format_field *field)
+{
+       struct bt_ctf_field_type *t = NULL;
+       char *name;
+       int dup = 1;
+       int ret;
+
+       /* alias was already assigned */
+       if (field->alias != field->name)
+               return bt_ctf_event_class_add_field(event_class, type,
+                               (char *)field->alias);
+
+       name = field->name;
+
+       /* If 'name' is a keywork, add prefix. */
+       if (bt_ctf_validate_identifier(name))
+               name = change_name(name, field->name, -1);
+
+       if (!name) {
+               pr_err("Failed to fix invalid identifier.");
+               return -1;
+       }
+       while ((t = bt_ctf_event_class_get_field_by_name(event_class, name))) {
+               bt_ctf_field_type_put(t);
+               name = change_name(name, field->name, dup++);
+               if (!name) {
+                       pr_err("Failed to create dup name for '%s'\n", field->name);
+                       return -1;
+               }
+       }
+
+       ret = bt_ctf_event_class_add_field(event_class, type, name);
+       if (!ret)
+               field->alias = name;
+
+       return ret;
+}
+
 static int add_tracepoint_fields_types(struct ctf_writer *cw,
                                       struct format_field *fields,
                                       struct bt_ctf_event_class *event_class)
@@ -595,14 +673,14 @@ static int add_tracepoint_fields_types(struct ctf_writer *cw,
                if (flags & FIELD_IS_ARRAY)
                        type = bt_ctf_field_type_array_create(type, field->arraylen);
 
-               ret = bt_ctf_event_class_add_field(event_class, type,
-                               field->name);
+               ret = event_class_add_field(event_class, type, field);
 
                if (flags & FIELD_IS_ARRAY)
                        bt_ctf_field_type_put(type);
 
                if (ret) {
-                       pr_err("Failed to add field '%s\n", field->name);
+                       pr_err("Failed to add field '%s': %d\n",
+                                       field->name, ret);
                        return -1;
                }
        }
@@ -646,7 +724,7 @@ static int add_generic_types(struct ctf_writer *cw, struct perf_evsel *evsel,
        do {                                                            \
                pr2("  field '%s'\n", n);                               \
                if (bt_ctf_event_class_add_field(cl, t, n)) {           \
-                       pr_err("Failed to add field '%s;\n", n);        \
+                       pr_err("Failed to add field '%s';\n", n);       \
                        return -1;                                      \
                }                                                       \
        } while (0)