perf tool: Fix gcc 4.6.0 issues

GCC 4.6.0 in Fedora rawhide turned up some compile errors in tools/perf
due to the -Werror=unused-but-set-variable flag.

I've gone through and annotated some of the assignments that had side
effects (ie: return value from a function) with the __used annotation,
and in some cases, just removed unused code.

In a few cases, we were assigning something useful, but not using it in
later parts of the function.

kyle@dreadnought:~/src% gcc --version
gcc (GCC) 4.6.0 20110122 (Red Hat 4.6.0-0.3)

Cc: Ingo Molnar <mingo@redhat.com>
LKML-Reference: <20110124161304.GK27353@bombadil.infradead.org>
Signed-off-by: Kyle McMartin <kyle@redhat.com>
[ committer note: Fixed up the annotation fixes, as that code moved recently ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

9 files changed, 11 insertions, 21 deletions

diff --git a/tools/perf/bench/sched-pipe.c b/tools/perf/bench/sched-pipe.c
index d9ab3ce446ac..0c7454f8b8a9 100644
--- a/tools/perf/bench/sched-pipe.c
+++ b/tools/perf/bench/sched-pipe.c
@@ -55,7 +55,7 @@ int bench_sched_pipe(int argc, const char **argv,
          * discarding returned value of read(), write()
          * causes error in building environment for perf
          */
-        int ret, wait_stat;
+        int __used ret, wait_stat;
         pid_t pid, retpid;
 
         argc = parse_options(argc, argv, options,
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index ae2621182927..a32f411faeac 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -369,11 +369,6 @@ static void
 process_sched_event(struct task_desc *this_task __used, struct sched_atom *atom)
 {
         int ret = 0;
-        u64 now;
-        long long delta;
-
-        now = get_nsecs();
-        delta = start_time + atom->timestamp - now;
 
         switch (atom->type) {
                 case SCHED_EVENT_RUN:
@@ -562,7 +557,7 @@ static void wait_for_tasks(void)
 
 static void run_one_test(void)
 {
-        u64 T0, T1, delta, avg_delta, fluct, std_dev;
+        u64 T0, T1, delta, avg_delta, fluct;
 
         T0 = get_nsecs();
         wait_for_tasks();
@@ -578,7 +573,6 @@ static void run_one_test(void)
         else
                 fluct = delta - avg_delta;
         sum_fluct += fluct;
-        std_dev = sum_fluct / nr_runs / sqrt(nr_runs);
         if (!run_avg)
                 run_avg = delta;
         run_avg = (run_avg*9 + delta)/10;
@@ -799,7 +793,7 @@ replay_switch_event(struct trace_switch_event *switch_event,
                     u64 timestamp,
                     struct thread *thread __used)
 {
-        struct task_desc *prev, *next;
+        struct task_desc *prev, __used *next;
         u64 timestamp0;
         s64 delta;
 
@@ -1404,7 +1398,7 @@ map_switch_event(struct trace_switch_event *switch_event,
                  u64 timestamp,
                  struct thread *thread __used)
 {
-        struct thread *sched_out, *sched_in;
+        struct thread *sched_out __used, *sched_in;
         int new_shortname;
         u64 timestamp0;
         s64 delta;
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 716118a3b3e4..b790673cb0aa 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -865,7 +865,7 @@ static int __cmd_top(void)
 {
         pthread_t thread;
         struct perf_evsel *first;
-        int ret;
+        int ret __used;
         /*
          * FIXME: perf_session__new should allow passing a O_MMAP, so that all this
          * mmap reading, etc is encapsulated in it. Use O_WRONLY for now.
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 297337649c21..1012841835a3 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -236,7 +236,6 @@ int symbol__annotate(struct symbol *sym, struct map *map,
         char command[PATH_MAX * 2];
         FILE *file;
         int err = 0;
-        u64 len;
         char symfs_filename[PATH_MAX];
 
         if (filename) {
@@ -281,8 +280,6 @@ fallback:
                  filename, sym->name, map->unmap_ip(map, sym->start),
                  map->unmap_ip(map, sym->end));
 
-        len = sym->end - sym->start;
-
         pr_debug("annotating [%p] %30s : [%p] %30s\n",
                  dso, dso->long_name, sym, sym->name);
 
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index c0de5ec44145..72c124dc5781 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1145,7 +1145,7 @@ int perf_event__synthesize_tracing_data(int fd, struct perf_evlist *evlist,
 {
         union perf_event ev;
         ssize_t size = 0, aligned_size = 0, padding;
-        int err = 0;
+        int err __used = 0;
 
         memset(&ev, 0, sizeof(ev));
 
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index c6d99334bdfa..2040b8538527 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -248,8 +248,7 @@ static void python_process_event(int cpu, void *data,
         context = PyCObject_FromVoidPtr(scripting_context, NULL);
 
         PyTuple_SetItem(t, n++, PyString_FromString(handler_name));
-        PyTuple_SetItem(t, n++,
-                        PyCObject_FromVoidPtr(scripting_context, NULL));
+        PyTuple_SetItem(t, n++, context);
 
         if (handler) {
                 PyTuple_SetItem(t, n++, PyInt_FromLong(cpu));
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 7821d0e6866f..3e193f8e3061 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1525,8 +1525,8 @@ int dso__load(struct dso *self, struct map *map, symbol_filter_t filter)
                              symbol_conf.symfs, self->long_name);
                         break;
                 case DSO__ORIG_GUEST_KMODULE:
-                        if (map->groups && map->groups->machine)
-                                root_dir = map->groups->machine->root_dir;
+                        if (map->groups && machine)
+                                root_dir = machine->root_dir;
                         else
                                 root_dir = "";
                         snprintf(name, size, "%s%s%s", symbol_conf.symfs,
diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 73a02223c629..d8e622dd738a 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -153,7 +153,7 @@ void parse_proc_kallsyms(char *file, unsigned int size __unused)
         char *next = NULL;
         char *addr_str;
         char ch;
-        int ret;
+        int ret __used;
         int i;
 
         line = strtok_r(file, "\n", &next);
diff --git a/tools/perf/util/ui/browsers/map.c b/tools/perf/util/ui/browsers/map.c
index e5158369106e..8462bffe20bc 100644
--- a/tools/perf/util/ui/browsers/map.c
+++ b/tools/perf/util/ui/browsers/map.c
@@ -41,7 +41,7 @@ static int ui_entry__read(const char *title, char *bf, size_t size, int width)
 out_free_form:
         newtPopWindow();
         newtFormDestroy(form);
-        return 0;
+        return err;
 }
 
 struct map_browser {