perf report: Add --no-demangle option

It's sometimes useful to see undemangled raw symbol name for example
other tools using the perf output to do manipulation of binaries.

Signed-off-by: Namhyung Kim <[email protected]>
Suggested-by: William Cohen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: William Cohen <[email protected]>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=55571
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: Namhyung Kim

tools/perf/Documentation/perf-report.txt

@@ -206,6 +206,10 @@ OPTIONS
 --group::
 	Show event group information together.
 
+--demangle::
+	Demangle symbol names to human readable form. It's enabled by default,
+	disable with --no-demangle.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-annotate[1]

tools/perf/builtin-report.c

@@ -692,6 +692,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 		    "use branch records for histogram filling", parse_branch_mode),
 	OPT_STRING(0, "objdump", &objdump_path, "path",
 		   "objdump binary to use for disassembly and annotations"),
+	OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle,
+		    "Disable symbol demangling"),
 	OPT_END()
 	};
 

tools/perf/util/symbol-elf.c

@@ -806,9 +806,12 @@ int dso__load_sym(struct dso *dso, struct map *map,
 		 * DWARF DW_compile_unit has this, but we don't always have access
 		 * to it...
 		 */
-		demangled = bfd_demangle(NULL, elf_name, DMGL_PARAMS | DMGL_ANSI);
-		if (demangled != NULL)
-			elf_name = demangled;
+		if (symbol_conf.demangle) {
+			demangled = bfd_demangle(NULL, elf_name,
+						 DMGL_PARAMS | DMGL_ANSI);
+			if (demangled != NULL)
+				elf_name = demangled;
+		}
 new_symbol:
 		f = symbol__new(sym.st_value, sym.st_size,
 				GELF_ST_BIND(sym.st_info), elf_name);

tools/perf/util/symbol.c

@@ -36,6 +36,7 @@ struct symbol_conf symbol_conf = {
 	.use_modules	  = true,
 	.try_vmlinux_path = true,
 	.annotate_src	  = true,
+	.demangle	  = true,
 	.symfs            = "",
 };
 

tools/perf/util/symbol.h

@@ -97,7 +97,8 @@ struct symbol_conf {
 			kptr_restrict,
 			annotate_asm_raw,
 			annotate_src,
-			event_group;
+			event_group,
+			demangle;
 	const char	*vmlinux_name,
 			*kallsyms_name,
 			*source_prefix,