perf tools: Work around strict aliasing related warnings
Older versions of GCC are rather stupid about strict aliasing:
util/trace-event-parse.c: In function 'parse_cmdlines':
util/trace-event-parse.c:93: warning: dereferencing type-punned pointer will break strict-aliasing rules
util/trace-event-parse.c: In function 'parse_proc_kallsyms':
util/trace-event-parse.c:155: warning: dereferencing type-punned pointer will break strict-aliasing rules
util/trace-event-parse.c:157: warning: dereferencing type-punned pointer will break strict-aliasing rules
util/trace-event-parse.c:158: warning: dereferencing type-punned pointer will break strict-aliasing rules
util/trace-event-parse.c: In function 'parse_ftrace_printk':
util/trace-event-parse.c:294: warning: dereferencing type-punned pointer will break strict-aliasing rules
util/trace-event-parse.c:295: warning: dereferencing type-punned pointer will break strict-aliasing rules
make: *** [util/trace-event-parse.o] Error 1
Make it clear to GCC that we intend with those pointers, by passing
them through via an explicit (void *) cast.
We might want to add -fno-strict-aliasing as well, like the kernel
itself does.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 665dac2..37b10c2 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -90,7 +90,7 @@
while (line) {
item = malloc_or_die(sizeof(*item));
sscanf(line, "%d %as", &item->pid,
- (float *)&item->comm); /* workaround gcc warning */
+ (float *)(void *)&item->comm); /* workaround gcc warning */
item->next = list;
list = item;
line = strtok_r(NULL, "\n", &next);
@@ -152,10 +152,10 @@
item = malloc_or_die(sizeof(*item));
item->mod = NULL;
ret = sscanf(line, "%as %c %as\t[%as",
- (float *)&addr_str, /* workaround gcc warning */
+ (float *)(void *)&addr_str, /* workaround gcc warning */
&ch,
- (float *)&item->func,
- (float *)&item->mod);
+ (float *)(void *)&item->func,
+ (float *)(void *)&item->mod);
item->addr = strtoull(addr_str, NULL, 16);
free(addr_str);
@@ -291,8 +291,8 @@
while (line) {
item = malloc_or_die(sizeof(*item));
ret = sscanf(line, "%as : %as",
- (float *)&addr_str, /* workaround gcc warning */
- (float *)&item->printk);
+ (float *)(void *)&addr_str, /* workaround gcc warning */
+ (float *)(void *)&item->printk);
item->addr = strtoull(addr_str, NULL, 16);
free(addr_str);