From 65014ab36196f6d86edc9ee23759d6930b9d89a8 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 2 Sep 2009 14:55:55 +0200 Subject: [PATCH] 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 Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- tools/perf/util/trace-event-info.c | 2 +- tools/perf/util/trace-event-parse.c | 12 ++++++------ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c index 8161527..6c9302a 100644 --- a/tools/perf/util/trace-event-info.c +++ b/tools/perf/util/trace-event-info.c @@ -188,7 +188,7 @@ int bigendian(void) unsigned char str[] = { 0x1, 0x2, 0x3, 0x4, 0x0, 0x0, 0x0, 0x0}; unsigned int *ptr; - ptr = (unsigned int *)str; + ptr = (unsigned int *)(void *)str; return *ptr == 0x01020304; } 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 @@ void parse_cmdlines(char *file, int size __unused) 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 @@ void parse_proc_kallsyms(char *file, unsigned int size __unused) 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 @@ void parse_ftrace_printk(char *file, unsigned int size __unused) 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); -- 1.8.2.3