perf probe: Add --funcs to show available functions in symtab

Add --funcs to show available functions in symtab.

Originally this feature came from Srikar's uprobes patches
( http://lkml.org/lkml/2010/8/27/244 )

e.g.
...
__ablkcipher_walk_complete
__absent_pages_in_range
__account_scheduler_latency
__add_pages
__alloc_pages_nodemask
__alloc_percpu
__alloc_reserved_percpu
__alloc_skb
__alloc_workqueue_key
__any_online_cpu
__ata_ehi_push_desc
...

This also supports symbols in module, e.g.

...
cleanup_module
cpuid_maxphyaddr
emulate_clts
emulate_instruction
emulate_int_real
emulate_invlpg
emulator_get_dr
emulator_set_dr
emulator_task_switch
emulator_write_emulated
emulator_write_phys
fx_init
...

Original-patch-from: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Franck Bui-Huu <fbuihuu@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20110113124611.22426.10835.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ committer note: Add missing elf.h for STB_GLOBAL that broke a RHEL4 build ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index add163c..6cf708a 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -52,6 +52,7 @@
 	bool show_lines;
 	bool show_vars;
 	bool show_ext_vars;
+	bool show_funcs;
 	bool mod_events;
 	int nevents;
 	struct perf_probe_event events[MAX_PROBES];
@@ -221,6 +222,8 @@
 	OPT__DRY_RUN(&probe_event_dry_run),
 	OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
 		 "Set how many probe points can be found for a probe."),
+	OPT_BOOLEAN('F', "funcs", &params.show_funcs,
+		    "Show potential probe-able functions."),
 	OPT_END()
 };
 
@@ -246,7 +249,7 @@
 		params.max_probe_points = MAX_PROBES;
 
 	if ((!params.nevents && !params.dellist && !params.list_events &&
-	     !params.show_lines))
+	     !params.show_lines && !params.show_funcs))
 		usage_with_options(probe_usage, options);
 
 	/*
@@ -267,12 +270,36 @@
 			pr_err(" Error: Don't use --list with --vars.\n");
 			usage_with_options(probe_usage, options);
 		}
+		if (params.show_funcs) {
+			pr_err("  Error: Don't use --list with --funcs.\n");
+			usage_with_options(probe_usage, options);
+		}
 		ret = show_perf_probe_events();
 		if (ret < 0)
 			pr_err("  Error: Failed to show event list. (%d)\n",
 			       ret);
 		return ret;
 	}
+	if (params.show_funcs) {
+		if (params.nevents != 0 || params.dellist) {
+			pr_err("  Error: Don't use --funcs with"
+			       " --add/--del.\n");
+			usage_with_options(probe_usage, options);
+		}
+		if (params.show_lines) {
+			pr_err("  Error: Don't use --funcs with --line.\n");
+			usage_with_options(probe_usage, options);
+		}
+		if (params.show_vars) {
+			pr_err("  Error: Don't use --funcs with --vars.\n");
+			usage_with_options(probe_usage, options);
+		}
+		ret = show_available_funcs(params.target_module);
+		if (ret < 0)
+			pr_err("  Error: Failed to show functions."
+			       " (%d)\n", ret);
+		return ret;
+	}
 
 #ifdef DWARF_SUPPORT
 	if (params.show_lines) {