linux-kernel - [PATCH 25/48] perf annotate-data: Handle macro fusion on x86

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Message-ID: <20231012035111.676789-26-namhyung@kernel.org>
Date:   Wed, 11 Oct 2023 20:50:48 -0700
From:   Namhyung Kim <namhyung@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Stephane Eranian <eranian@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        linux-toolchains@...r.kernel.org, linux-trace-devel@...r.kernel.org
Subject: [PATCH 25/48] perf annotate-data: Handle macro fusion on x86

When a sample was come from a conditional branch without a memory
operand, it could be due to a macro fusion with a previous instruction.
So it needs to check the memory operand in the previous one.

This improves the stat like below:

  Annotate data type stats:
  total 294, ok 147 (50.0%), bad 147 (50.0%)
  -----------------------------------------------------------
          30 : no_sym
          32 : no_mem_ops
          71 : no_var
           6 : no_typeinfo
           8 : bad_offset

Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
 tools/perf/util/annotate.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 190489df0fb7..b0893d8f2ae3 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -3710,6 +3710,7 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
 		return NULL;
 	}
 
+retry:
 	istat = annotate_data_stat(&ann_insn_stat, dl->ins.name);
 	if (istat == NULL) {
 		ann_data_stat.no_insn++;
@@ -3726,7 +3727,7 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
 		if (!op_loc->mem_ref)
 			continue;
 
-		/* Recalculate IP since it can be changed due to LOCK prefix */
+		/* Recalculate IP because of LOCK prefix or insn fusion */
 		ip = ms->sym->start + dl->al.offset;
 
 		mem_type = find_data_type(ms, ip, op_loc->reg, op_loc->offset);
@@ -3745,6 +3746,20 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
 		return mem_type;
 	}
 
+	/*
+	 * Some instructions can be fused and the actual memory access came
+	 * from the previous instruction.
+	 */
+	if (dl->al.offset > 0) {
+		struct disasm_line *prev_dl;
+
+		prev_dl = list_prev_entry(dl, al.node);
+		if (ins__is_fused(arch, prev_dl->ins.name, dl->ins.name)) {
+			dl = prev_dl;
+			goto retry;
+		}
+	}
+
 	ann_data_stat.no_mem_ops++;
 	istat->bad++;
 	return NULL;
-- 
2.42.0.655.g421f12c284-goog