perf probe: Fix !dwarf build

Fix the !drawf build.

This uses the existing NO_DWARF_SUPPORT mechanism we use for that,
but it's really fragile and needs a cleanup. (in a separate patch)

1) Such uses:

 #ifndef NO_DWARF_SUPPORT

are double inverted logic a'la 'not not'. Instead the flag should
be called DWARF_SUPPORT.

2) Furthermore, assymetric #ifdef polluted code flow like:

        if (need_dwarf)
 #ifdef NO_DWARF_SUPPORT
                die("Debuginfo-analysis is not supported");
 #else   /* !NO_DWARF_SUPPORT */
                pr_debug("Some probes require debuginfo.\n");

        fd = open_vmlinux();

is very fragile and not acceptable. Instead of that helper functions
should be created and the dwarf/no-dwarf logic should be separated more
cleanly.

3) Local variable #ifdefs like this:

 #ifndef NO_DWARF_SUPPORT
        int fd;
 #endif

Are fragile as well and should be eliminated. Helper functions achieve
that too.

Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220612.32050.33806.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/probe-event.c

@@ -1012,8 +1012,10 @@ static int convert_to_kprobe_trace_events(struct perf_probe_event *pev,
 	if (!sym)
 		die("Kernel symbol \'%s\' not found - probe not added.",
 		    tev->point.symbol);
+#ifndef NO_DWARF_SUPPORT
 found:
 	close(fd);
+#endif
 	return ntevs;
 }
 
@@ -1172,17 +1174,21 @@ void show_line_range(struct line_range *lr)
 	unsigned int l = 1;
 	struct line_node *ln;
 	FILE *fp;
+#ifndef NO_DWARF_SUPPORT
 	int fd, ret;
+#endif
 
 	/* Search a line range */
 	init_vmlinux();
+#ifndef NO_DWARF_SUPPORT
 	fd = open_vmlinux();
 	if (fd < 0)
 		die("Could not open debuginfo file.");
 	ret = find_line_range(fd, lr);
 	if (ret <= 0)
 		die("Source line is not found.\n");
 	close(fd);
+#endif
 
 	setup_pager();