lib: gcc 4.x workaround v2 for frr_interface_info

The previous workaround only works for -O0, at higher optimization
levels gcc reorders the statements in the file global scope which breaks
the asm statement :(.

Fixes: #4563
Fixes: #5074
Signed-off-by: David Lamparter <equinox@diac24.net>

1 files changed, 25 insertions, 10 deletions

diff --git a/lib/if.c b/lib/if.c
index f1565a089..20215640e 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -1650,7 +1650,32 @@ static int lib_interface_description_destroy(enum nb_event event,
 }
 
 /* clang-format off */
+
+#if defined(__GNUC__) && ((__GNUC__ - 0) < 5) && !defined(__clang__)
+/* gcc versions before 5.x miscalculate the size for structs with variable
+ * length arrays (they just count it as size 0)
+ */
+struct frr_yang_module_info_size3 {
+	/* YANG module name. */
+	const char *name;
+
+	/* Northbound callbacks. */
+	const struct {
+		/* Data path of this YANG node. */
+		const char *xpath;
+
+		/* Callbacks implemented for this node. */
+		struct nb_callbacks cbs;
+
+		/* Priority - lower priorities are processed first. */
+		uint32_t priority;
+	} nodes[3];
+};
+
+const struct frr_yang_module_info_size3 frr_interface_info_size3 asm("frr_interface_info") = {
+#else
 const struct frr_yang_module_info frr_interface_info = {
+#endif
 	.name = "frr-interface",
 	.nodes = {
 		{
@@ -1677,13 +1702,3 @@ const struct frr_yang_module_info frr_interface_info = {
 		},
 	}
 };
-
-#if defined(__GNUC__) && ((__GNUC__ - 0) < 5) && !defined(__clang__)
-/* gcc versions before 5.x miscalculate the size for structs with variable
- * length arrays (they just count it as size 0)
- *
- * NB: the "." below means "current position", i.e. this line must be
- * immediately after the frr_interface_info variable!
- */
-__asm__(".size\tfrr_interface_info, .-frr_interface_info\n");
-#endif