perf tools: Replace automatic const char[] variables by statics

An automatic const char[] variable gets initialized at runtime, just
like any other automatic variable. For long strings, that uses a lot of
stack and wastes time building the string; e.g. for the "No %s
allocation events..." case one has:

  444516:       48 b8 4e 6f 20 25 73 20 61 6c   movabs $0x6c61207325206f4e,%rax # "No %s al"
  ...
  444674:       48 89 45 80                     mov    %rax,-0x80(%rbp)
  444678:       48 b8 6c 6f 63 61 74 69 6f 6e   movabs $0x6e6f697461636f6c,%rax # "location"
  444682:       48 89 45 88                     mov    %rax,-0x78(%rbp)
  444686:       48 b8 20 65 76 65 6e 74 73 20   movabs $0x2073746e65766520,%rax # " events "
  444690:       66 44 89 55 c4                  mov    %r10w,-0x3c(%rbp)
  444695:       48 89 45 90                     mov    %rax,-0x70(%rbp)
  444699:       48 b8 66 6f 75 6e 64 2e 20 20   movabs $0x20202e646e756f66,%rax

Make them all static so that the compiler just references objects in .rodata.

Committer testing:

Ok, using dwarves's codiff tool:

    $ codiff --functions /tmp/perf.before ~/bin/perf
  builtin-sched.c:
    cmd_sched                 |  -48
   1 function changed, 48 bytes removed, diff: -48

  builtin-report.c:
    cmd_report                |  -32
   1 function changed, 32 bytes removed, diff: -32

  builtin-kmem.c:
    cmd_kmem                  |  -64
    build_alloc_func_list     |  -50
   2 functions changed, 114 bytes removed, diff: -114

  builtin-c2c.c:
    perf_c2c__report          | -390
   1 function changed, 390 bytes removed, diff: -390

  ui/browsers/header.c:
    tui__header_window        | -104
   1 function changed, 104 bytes removed, diff: -104

  /home/acme/bin/perf:
   9 functions changed, 688 bytes removed, diff: -688

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20181102230624.20064-1-linux@rasmusvillemoes.dk
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index b63bca4b0c2a..088705c167bf 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -334,7 +334,7 @@ static int build_alloc_func_list(void)
 	struct alloc_func *func;
 	struct machine *machine = &kmem_session->machines.host;
 	regex_t alloc_func_regex;
-	const char pattern[] = "^_?_?(alloc|get_free|get_zeroed)_pages?";
+	static const char pattern[] = "^_?_?(alloc|get_free|get_zeroed)_pages?";
 
 	ret = regcomp(&alloc_func_regex, pattern, REG_EXTENDED);
 	if (ret) {
@@ -1924,7 +1924,7 @@ int cmd_kmem(int argc, const char **argv)
 		NULL
 	};
 	struct perf_session *session;
-	const char errmsg[] = "No %s allocation events found.  Have you run 'perf kmem record --%s'?\n";
+	static const char errmsg[] = "No %s allocation events found.  Have you run 'perf kmem record --%s'?\n";
 	int ret = perf_config(kmem_config, NULL);
 
 	if (ret)