4 files changed, 96 insertions, 6 deletions

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 379f9d7a8ab1..1f668d4724e3 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -247,6 +247,19 @@ annotate.*::
 	These are in control of addresses, jump function, source code
 	in lines of assembly code from a specific program.
 
+	annotate.disassemblers::
+		Choose the disassembler to use: "objdump", "llvm",  "capstone",
+		if not specified it will first try, if available, the "llvm" one,
+		then, if it fails, "capstone", and finally the original "objdump"
+		based one.
+
+		Choosing a different one is useful when handling some feature that
+		is known to be best support at some point by one of the options,
+		to compare the output when in doubt about some bug, etc.
+
+		This can be a list, in order of preference, the first one that works
+		finishes the process.
+
 	annotate.addr2line::
 		addr2line binary to use for file names and line numbers.
 
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index b1d98da79be8..32e15c9f53f3 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -2116,6 +2116,12 @@ static int annotation__config(const char *var, const char *value, void *data)
 			opt->offset_level = ANNOTATION__MAX_OFFSET_LEVEL;
 		else if (opt->offset_level < ANNOTATION__MIN_OFFSET_LEVEL)
 			opt->offset_level = ANNOTATION__MIN_OFFSET_LEVEL;
+	} else if (!strcmp(var, "annotate.disassemblers")) {
+		opt->disassemblers_str = strdup(value);
+		if (!opt->disassemblers_str) {
+			pr_err("Not enough memory for annotate.disassemblers\n");
+			return -1;
+		}
 	} else if (!strcmp(var, "annotate.hide_src_code")) {
 		opt->hide_src_code = perf_config_bool("hide_src_code", value);
 	} else if (!strcmp(var, "annotate.jump_arrows")) {
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 8b9e05a1932f..194a05cbc506 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -34,6 +34,9 @@ struct annotated_data_type;
 #define ANNOTATION__BR_CNTR_WIDTH 30
 #define ANNOTATION_DUMMY_LEN	256
 
+// llvm, capstone, objdump
+#define MAX_DISASSEMBLERS 3
+
 struct annotation_options {
 	bool hide_src_code,
 	     use_offset,
@@ -49,11 +52,14 @@ struct annotation_options {
 	     annotate_src,
 	     full_addr;
 	u8   offset_level;
+	u8   nr_disassemblers;
 	int  min_pcnt;
 	int  max_lines;
 	int  context;
 	char *objdump_path;
 	char *disassembler_style;
+	const char *disassemblers_str;
+	const char *disassemblers[MAX_DISASSEMBLERS];
 	const char *prefix;
 	const char *prefix_strip;
 	unsigned int percent_type;
diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 6259dfe9aacc..41a2b08670dc 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -2213,13 +2213,65 @@ out_free_command:
 	return err;
 }
 
+static int annotation_options__init_disassemblers(struct annotation_options *options)
+{
+	char *disassembler;
+
+	if (options->disassemblers_str == NULL) {
+		const char *default_disassemblers_str =
+#ifdef HAVE_LIBLLVM_SUPPORT
+				"llvm,"
+#endif
+#ifdef HAVE_LIBCAPSTONE_SUPPORT
+				"capstone,"
+#endif
+				"objdump";
+
+		options->disassemblers_str = strdup(default_disassemblers_str);
+		if (!options->disassemblers_str)
+			goto out_enomem;
+	}
+
+	disassembler = strdup(options->disassemblers_str);
+	if (disassembler == NULL)
+		goto out_enomem;
+
+	while (1) {
+		char *comma = strchr(disassembler, ',');
+
+		if (comma != NULL)
+			*comma = '\0';
+
+		options->disassemblers[options->nr_disassemblers++] = strim(disassembler);
+
+		if (comma == NULL)
+			break;
+
+		disassembler = comma + 1;
+
+		if (options->nr_disassemblers >= MAX_DISASSEMBLERS) {
+			pr_debug("annotate.disassemblers can have at most %d entries, ignoring \"%s\"\n",
+				 MAX_DISASSEMBLERS, disassembler);
+			break;
+		}
+	}
+
+	return 0;
+
+out_enomem:
+	pr_err("Not enough memory for annotate.disassemblers\n");
+	return -1;
+}
+
 int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
 {
+	struct annotation_options *options = args->options;
 	struct map *map = args->ms.map;
 	struct dso *dso = map__dso(map);
 	char symfs_filename[PATH_MAX];
 	bool delete_extract = false;
 	struct kcore_extract kce;
+	const char *disassembler;
 	bool decomp = false;
 	int err = dso__disassemble_filename(dso, symfs_filename, sizeof(symfs_filename));
 
@@ -2279,16 +2331,29 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args)
 		}
 	}
 
-	err = symbol__disassemble_llvm(symfs_filename, sym, args);
-	if (err == 0)
+	err = annotation_options__init_disassemblers(options);
+	if (err)
 		goto out_remove_tmp;
 
-	err = symbol__disassemble_capstone(symfs_filename, sym, args);
-	if (err == 0)
-		goto out_remove_tmp;
+	err = -1;
 
-	err = symbol__disassemble_objdump(symfs_filename, sym, args);
+	for (int i = 0; i < options->nr_disassemblers && err != 0; ++i) {
+		disassembler = options->disassemblers[i];
 
+		if (!strcmp(disassembler, "llvm"))
+			err = symbol__disassemble_llvm(symfs_filename, sym, args);
+		else if (!strcmp(disassembler, "capstone"))
+			err = symbol__disassemble_capstone(symfs_filename, sym, args);
+		else if (!strcmp(disassembler, "objdump"))
+			err = symbol__disassemble_objdump(symfs_filename, sym, args);
+		else
+			pr_debug("Unknown disassembler %s, skipping...\n", disassembler);
+	}
+
+	if (err == 0) {
+		pr_debug("Disassembled with %s\nannotate.disassemblers=%s\n",
+			 disassembler, options->disassemblers_str);
+	}
 out_remove_tmp:
 	if (decomp)
 		unlink(symfs_filename);