perf/probes: Improve probe point syntax of perf-probe

This changes probe point syntax of perf-probe as below

 <SRC>[:ABS_LN] [ARGS]
 or
 <FUNC>[+OFFS|%return][@SRC] [ARGS]

And event name and event group name are automatically
generated based on probe-symbol and offset as below.

 perfprobes/SYMBOL_OFFSET[_NUM]

Where SYMBOL is the probing symbol and OFFSET is
the byte offset from the symbol.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
LKML-Reference: <20091027204310.30545.84984.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index b98d35e..6d3bac9 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -483,10 +483,20 @@
 	if (ret == DW_DLV_OK) {
 		ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name,
 				(unsigned int)offs);
+		/* Copy the function name if possible */
+		if (!pp->function) {
+			pp->function = strdup(name);
+			pp->offset = offs;
+		}
 		dwarf_dealloc(__dw_debug, name, DW_DLA_STRING);
 	} else {
 		/* This function has no name. */
 		ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr);
+		if (!pp->function) {
+			/* TODO: Use _stext */
+			pp->function = strdup("");
+			pp->offset = (int)pf->addr;
+		}
 	}
 	DIE_IF(ret < 0);
 	DIE_IF(ret >= MAX_PROBE_BUFFER);