[PATCH V6 3/3] perf tool: check buildid for symoff

[Kan Liang <kan.liang@intel.com>]

From: Kan Liang <kan.liang@intel.com>

symoff can support both same binaries and different binaries. However,
the offset may be changed for different binaries. This patch checks the
buildid of perf.data. If they are from different binaries, print a
warning to notify the user.

Signed-off-by: Kan Liang <kan.liang@intel.com>
---

Changes since V5:
 - Warning once.
 - Print build-ids with --verbose

 tools/perf/builtin-diff.c | 41 +++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/sort.c    |  3 +++
 tools/perf/util/sort.h    |  1 +
 3 files changed, 45 insertions(+)

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 03a4001..7f1cb6a 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -17,6 +17,7 @@
 #include "util/symbol.h"
 #include "util/util.h"
 #include "util/data.h"
+#include "asm/bug.h"
 
 #include <stdlib.h>
 #include <math.h>
@@ -678,6 +679,43 @@ static void data__free(struct data__file *d)
 	}
 }
 
+static void buildid_check(void)
+{
+	struct dsos *base_k_dsos = &data__files[0].session->machines.host.kernel_dsos;
+	struct dsos *base_u_dsos = &data__files[0].session->machines.host.user_dsos;
+	struct dsos *k_dsos_tmp, *u_dsos_tmp;
+	struct data__file *d;
+	bool k_warn, u_warn;
+	bool first = true;
+	int i;
+
+	data__for_each_file_new(i, d) {
+		k_dsos_tmp = &d->session->machines.host.kernel_dsos;
+		u_dsos_tmp = &d->session->machines.host.user_dsos;
+
+		k_warn = !dsos__build_ids_common_equal(base_k_dsos, k_dsos_tmp);
+		u_warn = !dsos__build_ids_common_equal(base_u_dsos, u_dsos_tmp);
+
+		WARN_ONCE(k_warn | u_warn, "The perf.data come from different %s%s%s. "
+					   "The symbol offset may vary. Please apply --verbose for details.\n",
+					   k_warn ? "kernel" : "",
+					   (k_warn && u_warn) ? " and " : "",
+					   u_warn ? "user binary" : "");
+
+		if (verbose) {
+			if (first) {
+				fprintf(stdout, "# ========%s (Baseline) build-ids\n", data__files[0].file.path);
+				machine__fprintf_dsos_buildid(&data__files[0].session->machines.host, stdout, NULL, 0);
+				fprintf(stdout, "# ========\n#\n");
+				first = false;
+			}
+			fprintf(stdout, "# ========%s build-ids\n", d->file.path);
+			machine__fprintf_dsos_buildid(&d->session->machines.host, stdout, NULL, 0);
+			fprintf(stdout, "# ========\n#\n");
+		}
+	}
+}
+
 static int __cmd_diff(void)
 {
 	struct data__file *d;
@@ -700,6 +738,9 @@ static int __cmd_diff(void)
 		perf_evlist__collapse_resort(d->session->evlist);
 	}
 
+	if (sort__has_symoff)
+		buildid_check();
+
 	data_process();
 
  out_delete:
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 2a1df9f..07cfc4f 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -21,6 +21,7 @@ int		sort__need_collapse = 0;
 int		sort__has_parent = 0;
 int		sort__has_sym = 0;
 int		sort__has_dso = 0;
+int		sort__has_symoff = 0;
 enum sort_mode	sort__mode = SORT_MODE__NORMAL;
 
 
@@ -1495,6 +1496,7 @@ int sort_dimension__add(const char *tok)
 		} else if (sd->entry == &sort_dso) {
 			sort__has_dso = 1;
 		} else if (sd->entry == &sort_symoff) {
+			sort__has_symoff = 1;
 			/*
 			 * For symoff sort key, not only the offset but also the
 			 * symbol name should be compared.
@@ -1879,6 +1881,7 @@ void reset_output_field(void)
 	sort__has_parent = 0;
 	sort__has_sym = 0;
 	sort__has_dso = 0;
+	sort__has_symoff = 0;
 
 	field_order = NULL;
 	sort_order = NULL;
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index ea0122f..d2f9782 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -34,6 +34,7 @@ extern int have_ignore_callees;
 extern int sort__need_collapse;
 extern int sort__has_parent;
 extern int sort__has_sym;
+extern int sort__has_symoff;
 extern enum sort_mode sort__mode;
 extern struct sort_entry sort_comm;
 extern struct sort_entry sort_dso;
-- 
1.8.3.2