perf tools: Add ability to synthesize event according to a sample

It's the counterpart of perf_session__parse_sample.

v2: fixed mistakes found by David Ahern.
v3: s/data/sample/
    s/perf_event__change_sample/perf_event__synthesize_sample

Reviewed-by: David Ahern <dsahern@gmail.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: devel@openvz.org
Link: http://lkml.kernel.org/r/1323266161-394927-3-git-send-email-avagin@openvz.org
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 90 insertions, 0 deletions

diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 0d80201ce844..cbdeaad9c5e5 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -199,6 +199,9 @@ const char *perf_event__name(unsigned int id);
 int perf_event__parse_sample(const union perf_event *event, u64 type,
                              int sample_size, bool sample_id_all,
                              struct perf_sample *sample, bool swapped);
+int perf_event__synthesize_sample(union perf_event *event, u64 type,
+                                  const struct perf_sample *sample,
+                                  bool swapped);
 
 size_t perf_event__fprintf_comm(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_mmap(union perf_event *event, FILE *fp);
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ee68d6944e61..4a8c8b02e9cc 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -574,3 +574,82 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
 
         return 0;
 }
+
+int perf_event__synthesize_sample(union perf_event *event, u64 type,
+                                  const struct perf_sample *sample,
+                                  bool swapped)
+{
+        u64 *array;
+
+        /*
+         * used for cross-endian analysis. See git commit 65014ab3
+         * for why this goofiness is needed.
+         */
+        union {
+                u64 val64;
+                u32 val32[2];
+        } u;
+
+        array = event->sample.array;
+
+        if (type & PERF_SAMPLE_IP) {
+                event->ip.ip = sample->ip;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_TID) {
+                u.val32[0] = sample->pid;
+                u.val32[1] = sample->tid;
+                if (swapped) {
+                        /*
+                         * Inverse of what is done in perf_event__parse_sample
+                         */
+                        u.val32[0] = bswap_32(u.val32[0]);
+                        u.val32[1] = bswap_32(u.val32[1]);
+                        u.val64 = bswap_64(u.val64);
+                }
+
+                *array = u.val64;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_TIME) {
+                *array = sample->time;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_ADDR) {
+                *array = sample->addr;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_ID) {
+                *array = sample->id;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_STREAM_ID) {
+                *array = sample->stream_id;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_CPU) {
+                u.val32[0] = sample->cpu;
+                if (swapped) {
+                        /*
+                         * Inverse of what is done in perf_event__parse_sample
+                         */
+                        u.val32[0] = bswap_32(u.val32[0]);
+                        u.val64 = bswap_64(u.val64);
+                }
+                *array = u.val64;
+                array++;
+        }
+
+        if (type & PERF_SAMPLE_PERIOD) {
+                *array = sample->period;
+                array++;
+        }
+
+        return 0;
+}
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 30e9c6b6fc3c..fb696124ad61 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -134,6 +134,14 @@ static inline int perf_session__parse_sample(struct perf_session *session,
                                         session->header.needs_swap);
 }
 
+static inline int perf_session__synthesize_sample(struct perf_session *session,
+                                                  union perf_event *event,
+                                                  const struct perf_sample *sample)
+{
+        return perf_event__synthesize_sample(event, session->sample_type,
+                                             sample, session->header.needs_swap);
+}
+
 struct perf_evsel *perf_session__find_first_evtype(struct perf_session *session,
                                             unsigned int type);