perf probe: Support function@filename syntax for --line

Since "perf probe --add" supports function@filename syntax, --line
option should also support it.

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: linux-kernel@vger.kernel.org
LKML-Reference: <20110210090810.1809.26913.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-probe.txt

@@ -16,7 +16,7 @@ or
 or
 'perf probe' --list
 or
-'perf probe' [options] --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'
+'perf probe' [options] --line='LINE'
 or
 'perf probe' [options] --vars='PROBEPOINT'
 
@@ -128,13 +128,14 @@ LINE SYNTAX
 -----------
 Line range is described by following syntax.
 
- "FUNC[:RLN[+NUM|-RLN2]]|SRC[:ALN[+NUM|-ALN2]]"
+ "FUNC[@SRC][:RLN[+NUM|-RLN2]]|SRC[:ALN[+NUM|-ALN2]]"
 
 FUNC specifies the function name of showing lines. 'RLN' is the start line
 number from function entry line, and 'RLN2' is the end line number. As same as
 probe syntax, 'SRC' means the source file path, 'ALN' is start line number,
 and 'ALN2' is end line number in the file. It is also possible to specify how
-many lines to show by using 'NUM'.
+many lines to show by using 'NUM'. Moreover, 'FUNC@SRC' combination is good
+for searching a specific function when several functions share same name.
 So, "source.c:100-120" shows lines between 100th to l20th in source.c file. And "func:10+20" shows 20 lines from 10th line of func function.
 
 LAZY MATCHING

tools/perf/util/probe-event.c

@@ -595,11 +595,11 @@ static int parse_line_num(char **ptr, int *val, const char *what)
  * The line range syntax is described by:
  *
  *         SRC[:SLN[+NUM|-ELN]]
- *         FNC[:SLN[+NUM|-ELN]]
+ *         FNC[@SRC][:SLN[+NUM|-ELN]]
  */
 int parse_line_range_desc(const char *arg, struct line_range *lr)
 {
-	char *range, *name = strdup(arg);
+	char *range, *file, *name = strdup(arg);
 	int err;
 
 	if (!name)
@@ -649,7 +649,16 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
 		}
 	}
 
-	if (strchr(name, '.'))
+	file = strchr(name, '@');
+	if (file) {
+		*file = '\0';
+		lr->file = strdup(++file);
+		if (lr->file == NULL) {
+			err = -ENOMEM;
+			goto err;
+		}
+		lr->function = name;
+	} else if (strchr(name, '.'))
 		lr->file = name;
 	else
 		lr->function = name;