cmake/compiler/xcc: sched: Support XCC inlining semantics

Cadence XCC is based off of a very old 4.2 gcc compiler, which didn't
perfectly support C99 "inline" semantics with respect to
cross-translation-unit inline linkage (which Zephyr does not use, our
inlines are static only) and declaration order.

Fix the one spot where we were calling an inline before its
ALWAYS_INLINE definition, and add a flag to suppress the warning so
CI's trying to build with XCC and -Werror don't flip out.

Signed-off-by: Andy Ross <[email protected]>

Author: Andy Ross

cmake/compiler/xcc/compiler_flags.cmake

@@ -4,4 +4,10 @@ if(CC STREQUAL "clang")
   include(${ZEPHYR_BASE}/cmake/compiler/clang/compiler_flags.cmake)
 else()
   include(${ZEPHYR_BASE}/cmake/compiler/gcc/compiler_flags.cmake)
+
+  # XCC is based on GCC 4.2 which has a somewhat pedantic take on the
+  # fact that linkage semantics differed between C99 and GNU at the
+  # time.  Suppress the warning, it's the best we can do given that
+  # it's a legacy compiler.
+  set_compiler_property(APPEND PROPERTY warning_base "-fgnu89-inline")
 endif()

kernel/sched.c

@@ -170,6 +170,23 @@ static ALWAYS_INLINE struct k_thread *_priq_dumb_mask_best(sys_dlist_t *pq)
 }
 #endif
 
+ALWAYS_INLINE void z_priq_dumb_add(sys_dlist_t *pq, struct k_thread *thread)
+{
+	struct k_thread *t;
+
+	__ASSERT_NO_MSG(!z_is_idle_thread_object(thread));
+
+	SYS_DLIST_FOR_EACH_CONTAINER(pq, t, base.qnode_dlist) {
+		if (z_sched_prio_cmp(thread, t) > 0) {
+			sys_dlist_insert(&t->base.qnode_dlist,
+					 &thread->base.qnode_dlist);
+			return;
+		}
+	}
+
+	sys_dlist_append(pq, &thread->base.qnode_dlist);
+}
+
 /* _current is never in the run queue until context switch on
  * SMP configurations, see z_requeue_current()
  */
@@ -927,23 +944,6 @@ void *z_get_next_switch_handle(void *interrupted)
 }
 #endif
 
-ALWAYS_INLINE void z_priq_dumb_add(sys_dlist_t *pq, struct k_thread *thread)
-{
-	struct k_thread *t;
-
-	__ASSERT_NO_MSG(!z_is_idle_thread_object(thread));
-
-	SYS_DLIST_FOR_EACH_CONTAINER(pq, t, base.qnode_dlist) {
-		if (z_sched_prio_cmp(thread, t) > 0) {
-			sys_dlist_insert(&t->base.qnode_dlist,
-					 &thread->base.qnode_dlist);
-			return;
-		}
-	}
-
-	sys_dlist_append(pq, &thread->base.qnode_dlist);
-}
-
 void z_priq_dumb_remove(sys_dlist_t *pq, struct k_thread *thread)
 {
 	__ASSERT_NO_MSG(!z_is_idle_thread_object(thread));