perf: Enable more compiler warnings

Related to a shadowed variable bug fix Valdis Kletnieks noticed
that perf does not get built with -Wshadow, which could have
helped us avoid the bug.

So enable -Wshadow and also enable the following warnings on
perf builds, in addition to the already enabled -Wall -Wextra
-std=gnu99 warnings:

 -Wcast-align
 -Wformat=2
 -Wshadow
 -Winit-self
 -Wpacked
 -Wredundant-decls
 -Wstack-protector
 -Wstrict-aliasing=3
 -Wswitch-default
 -Wswitch-enum
 -Wno-system-headers
 -Wundef
 -Wvolatile-register-var
 -Wwrite-strings
 -Wbad-function-cast
 -Wmissing-declarations
 -Wmissing-prototypes
 -Wnested-externs
 -Wold-style-definition
 -Wstrict-prototypes
 -Wdeclaration-after-statement

And change/fix the perf code to build cleanly under GCC 4.3.2.

The list of warnings enablement is rather arbitrary: it's based
on my (quick) reading of the GCC manpages and trying them on
perf.

I categorized the warnings based on individually enabling them
and looking whether they trigger something in the perf build.
If i liked those warnings (i.e. if they trigger for something
that arguably could be improved) i enabled the warning.

If the warnings seemed to come from language laywers spamming
the build with tons of nuisance warnings i generally kept them
off. Most of the sign conversion related warnings were in
this category. (A second patch enabling some of the sign
warnings might be welcome - sign bugs can be nasty.)

I also kept warnings that seem to make sense from their manpage
description and which produced no actual warnings on our code
base. These warnings might still be turned off if they end up
being a nuisance.

I also left out a few warnings that are not supported in older
compilers.

[ Note that these changes might break the build on older
  compilers i did not test, or on non-x86 architectures that
  produce different warnings, so more testing would be welcome. ]

Reported-by: Valdis.Kletnieks@vt.edu
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>

1 files changed, 20 insertions, 18 deletions

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 298f26b8ac78..3b9d24dc0eda 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -97,6 +97,7 @@ static int repsep_fprintf(FILE *fp, const char *fmt, ...)
                 n = vasprintf(&bf, fmt, ap);
                 if (n > 0) {
                         char *sep = bf;
+
                         while (1) {
                                 sep = strchr(sep, *field_sep);
                                 if (sep == NULL)
@@ -144,7 +145,7 @@ struct hist_entry {
 struct sort_entry {
         struct list_head list;
 
-        char *header;
+        const char *header;
 
         int64_t (*cmp)(struct hist_entry *, struct hist_entry *);
         int64_t (*collapse)(struct hist_entry *, struct hist_entry *);
@@ -328,7 +329,7 @@ static int sort__need_collapse = 0;
 static int sort__has_parent = 0;
 
 struct sort_dimension {
-        char                    *name;
+        const char              *name;
         struct sort_entry       *entry;
         int                     taken;
 };
@@ -343,7 +344,7 @@ static struct sort_dimension sort_dimensions[] = {
 
 static LIST_HEAD(hist_entry__sort_list);
 
-static int sort_dimension__add(char *tok)
+static int sort_dimension__add(const char *tok)
 {
         unsigned int i;
 
@@ -602,6 +603,7 @@ hist_entry_callchain__fprintf(FILE *fp, struct hist_entry *self,
                 case CHAIN_GRAPH_REL:
                         ret += callchain__fprintf_graph(fp, chain,
                                                         total_samples, 1, 1);
+                case CHAIN_NONE:
                 default:
                         break;
                 }
@@ -1290,7 +1292,7 @@ process_lost_event(event_t *event, unsigned long offset, unsigned long head)
 static void trace_event(event_t *event)
 {
         unsigned char *raw_event = (void *)event;
-        char *color = PERF_COLOR_BLUE;
+        const char *color = PERF_COLOR_BLUE;
         int i, j;
 
         if (!dump_trace)
@@ -1348,7 +1350,7 @@ process_read_event(event_t *event, unsigned long offset, unsigned long head)
         struct perf_counter_attr *attr = perf_header__find_attr(event->read.id);
 
         if (show_threads) {
-                char *name = attr ? __event_name(attr->type, attr->config)
+                const char *name = attr ? __event_name(attr->type, attr->config)
                                    : "unknown";
                 perf_read_values_add_value(&show_threads_values,
                                            event->read.pid, event->read.tid,
@@ -1411,19 +1413,19 @@ process_event(event_t *event, unsigned long offset, unsigned long head)
 
 static u64 perf_header__sample_type(void)
 {
-        u64 sample_type = 0;
+        u64 type = 0;
         int i;
 
         for (i = 0; i < header->attrs; i++) {
                 struct perf_header_attr *attr = header->attr[i];
 
-                if (!sample_type)
-                        sample_type = attr->attr.sample_type;
-                else if (sample_type != attr->attr.sample_type)
+                if (!type)
+                        type = attr->attr.sample_type;
+                else if (type != attr->attr.sample_type)
                         die("non matching sample_type");
         }
 
-        return sample_type;
+        return type;
 }
 
 static int __cmd_report(void)
@@ -1431,7 +1433,7 @@ static int __cmd_report(void)
         int ret, rc = EXIT_FAILURE;
         unsigned long offset = 0;
         unsigned long head, shift;
-        struct stat stat;
+        struct stat input_stat;
         event_t *event;
         uint32_t size;
         char *buf;
@@ -1450,13 +1452,13 @@ static int __cmd_report(void)
                 exit(-1);
         }
 
-        ret = fstat(input, &stat);
+        ret = fstat(input, &input_stat);
         if (ret < 0) {
                 perror("failed to stat file");
                 exit(-1);
         }
 
-        if (!stat.st_size) {
+        if (!input_stat.st_size) {
                 fprintf(stderr, "zero-sized file, nothing to do!\n");
                 exit(0);
         }
@@ -1524,12 +1526,12 @@ more:
                 size = 8;
 
         if (head + event->header.size >= page_size * mmap_window) {
-                int ret;
+                int munmap_ret;
 
                 shift = page_size * (head / page_size);
 
-                ret = munmap(buf, page_size * mmap_window);
-                assert(ret == 0);
+                munmap_ret = munmap(buf, page_size * mmap_window);
+                assert(munmap_ret == 0);
 
                 offset += shift;
                 head -= shift;
@@ -1568,7 +1570,7 @@ more:
         if (offset + head >= header->data_offset + header->data_size)
                 goto done;
 
-        if (offset + head < (unsigned long)stat.st_size)
+        if (offset + head < (unsigned long)input_stat.st_size)
                 goto more;
 
 done:
@@ -1666,7 +1668,7 @@ static const struct option options[] = {
                     "be more verbose (show symbol address, etc)"),
         OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
                     "dump raw trace in ASCII"),
-        OPT_STRING('k', "vmlinux", &vmlinux, "file", "vmlinux pathname"),
+        OPT_STRING('k', "vmlinux", &vmlinux_name, "file", "vmlinux pathname"),
         OPT_BOOLEAN('m', "modules", &modules,
                     "load module symbols - WARNING: use only with -k and LIVE kernel"),
         OPT_BOOLEAN('n', "show-nr-samples", &show_nr_samples,