linux-kernel - [PATCH V4 12/13] perf tools: remove nop at end of annotation

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Date:	Wed,  7 Aug 2013 14:38:56 +0300
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Cc:	linux-kernel@...r.kernel.org, David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>,
	Namhyung Kim <namhyung@...il.com>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>,
	Ingo Molnar <mingo@...nel.org>
Subject: [PATCH V4 12/13] perf tools: remove nop at end of annotation

When kcore is used for annotation, symbols do not
have correct sizes because they come from kallsyms.
That sometimes results in an extra nop being seen
after the end of a function.  Remove it.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/annotate.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 4ab2f11..646e38d 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -830,6 +830,30 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
 	return 0;
 }
 
+static void delete_last_nop(struct symbol *sym)
+{
+	struct annotation *notes = symbol__annotation(sym);
+	struct list_head *list = &notes->src->source;
+	struct disasm_line *dl;
+
+	while (!list_empty(list)) {
+		dl = list_entry(list->prev, struct disasm_line, node);
+
+		if (dl->ins && dl->ins->ops) {
+			if (dl->ins->ops != &nop_ops)
+				return;
+		} else {
+			if (!strstr(dl->line, " nop ") &&
+			    !strstr(dl->line, " nopl ") &&
+			    !strstr(dl->line, " nopw "))
+				return;
+		}
+
+		list_del(&dl->node);
+		disasm_line__free(dl);
+	}
+}
+
 int symbol__annotate(struct symbol *sym, struct map *map, size_t privsize)
 {
 	struct dso *dso = map->dso;
@@ -923,6 +947,13 @@ fallback:
 		if (symbol__parse_objdump_line(sym, map, file, privsize) < 0)
 			break;
 
+	/*
+	 * kallsyms does not have symbol sizes so there may a nop at the end.
+	 * Remove it.
+	 */
+	if (dso__is_kcore(dso))
+		delete_last_nop(sym);
+
 	pclose(file);
 out_free_filename:
 	if (free_filename)
-- 
1.7.11.7

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