[PATCH 38/40] perf jevents: Make build fail on JSON parse error

From: Arnaldo Carvalho de Melo
Date: Wed Jul 26 2017 - 10:22:33 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Today, when a JSON file fails parsing the build continues, but there are
no json files built in, which is difficult to debug later. Make the
build stop on a parse error instead.

v2: Add fixes from Sukadev. Now we handle architectures
with no JSON events correctly. And fix some stale comments.

Committer note:

Tested by running the cross build container tests, that were all failing
for v1.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170725001638.19990-1-andi@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/pmu-events/README | 4 ----
tools/perf/pmu-events/jevents.c | 21 ++++++++++++++-------
2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/tools/perf/pmu-events/README b/tools/perf/pmu-events/README
index 1408ade0d773..c2ee3e4417fe 100644
--- a/tools/perf/pmu-events/README
+++ b/tools/perf/pmu-events/README
@@ -85,10 +85,6 @@ users to specify events by their name:

where 'pm_1plus_ppc_cmpl' is a Power8 PMU event.

-In case of errors when processing files in the tools/perf/pmu-events/arch
-directory, 'jevents' tries to create an empty mapping file to allow the perf
-build to succeed even if the PMU event aliases cannot be used.
-
However some errors in processing may cause the perf build to fail.

Mapfile format
diff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c
index bd0aabb2bd0f..2350f6099a46 100644
--- a/tools/perf/pmu-events/jevents.c
+++ b/tools/perf/pmu-events/jevents.c
@@ -822,10 +822,6 @@ static int process_one_file(const char *fpath, const struct stat *sb,
* PMU event tables (see struct pmu_events_map).
*
* Write out the PMU events tables and the mapping table to pmu-event.c.
- *
- * If unable to process the JSON or arch files, create an empty mapping
- * table so we can continue to build/use perf even if we cannot use the
- * PMU event aliases.
*/
int main(int argc, char *argv[])
{
@@ -836,6 +832,7 @@ int main(int argc, char *argv[])
const char *arch;
const char *output_file;
const char *start_dirname;
+ struct stat stbuf;

prog = basename(argv[0]);
if (argc < 4) {
@@ -857,11 +854,17 @@ int main(int argc, char *argv[])
return 2;
}

+ sprintf(ldirname, "%s/%s", start_dirname, arch);
+
+ /* If architecture does not have any event lists, bail out */
+ if (stat(ldirname, &stbuf) < 0) {
+ pr_info("%s: Arch %s has no PMU event lists\n", prog, arch);
+ goto empty_map;
+ }
+
/* Include pmu-events.h first */
fprintf(eventsfp, "#include \"../../pmu-events/pmu-events.h\"\n");

- sprintf(ldirname, "%s/%s", start_dirname, arch);
-
/*
* The mapfile allows multiple CPUids to point to the same JSON file,
* so, not sure if there is a need for symlinks within the pmu-events
@@ -878,6 +881,9 @@ int main(int argc, char *argv[])
if (rc && verbose) {
pr_info("%s: Error walking file tree %s\n", prog, ldirname);
goto empty_map;
+ } else if (rc < 0) {
+ /* Make build fail */
+ return 1;
} else if (rc) {
goto empty_map;
}
@@ -892,7 +898,8 @@ int main(int argc, char *argv[])

if (process_mapfile(eventsfp, mapfile)) {
pr_info("%s: Error processing mapfile %s\n", prog, mapfile);
- goto empty_map;
+ /* Make build fail */
+ return 1;
}

return 0;
--
2.9.4