perf dso: Fix build when libunwind is enabled

Now that symsrc_filename is always accessed through an accessor, we also
need a free() function for it to avoid the following compilation error:

  util/unwind-libunwind-local.c:416:12: error: lvalue required as unary
    ‘&’ operand
  416 |      zfree(&dso__symsrc_filename(dso));

Fixes: 1553419c ("perf dso: Fix address sanitizer build")
Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Yunseong Kim <yskelg@gmail.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20240715094715.3914813-1-james.clark@linaro.orgSigned-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/util/dso.c

@@ -1501,7 +1501,7 @@ void dso__delete(struct dso *dso)
 	auxtrace_cache__free(RC_CHK_ACCESS(dso)->auxtrace_cache);
 	dso_cache__free(dso);
 	dso__free_a2l(dso);
-	zfree(&RC_CHK_ACCESS(dso)->symsrc_filename);
+	dso__free_symsrc_filename(dso);
 	nsinfo__zput(RC_CHK_ACCESS(dso)->nsinfo);
 	mutex_destroy(dso__lock(dso));
 	RC_CHK_FREE(dso);

tools/perf/util/dso.h

@@ -602,6 +602,11 @@ static inline void dso__set_symsrc_filename(struct dso *dso, char *val)
 	RC_CHK_ACCESS(dso)->symsrc_filename = val;
 }
 
+static inline void dso__free_symsrc_filename(struct dso *dso)
+{
+	zfree(&RC_CHK_ACCESS(dso)->symsrc_filename);
+}
+
 static inline enum dso_binary_type dso__symtab_type(const struct dso *dso)
 {
 	return RC_CHK_ACCESS(dso)->symtab_type;

tools/perf/util/unwind-libunwind-local.c

@@ -413,7 +413,7 @@ static int read_unwind_spec_debug_frame(struct dso *dso,
 							__func__,
 							dso__symsrc_filename(dso),
 							debuglink);
-					zfree(&dso__symsrc_filename(dso));
+					dso__free_symsrc_filename(dso);
 				}
 				dso__set_symsrc_filename(dso, debuglink);
 			} else {