libsel4vm: Force optimisation level for release

As the comment in the file explains, optimisation level -O3 on gcc 8.4 is too aggressive and causes issues for the guest VM. The problem isn't limited to a single function or group of functions but rather the entire file for some reason that requires extra investigation (but is not worth the time to do so). Signed-off-by: Damon Lee <[email protected]>
seL4 · Apr 9, 2021 · 0f9286d · 0f9286d
1 parent adf3588
commit 0f9286d
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/libsel4vm/src/arch/x86/guest_x86_context.c b/libsel4vm/src/arch/x86/guest_x86_context.c
@@ -4,6 +4,13 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+/* Under release mode, this file will get built using -O3. Howerver on gcc 8.4,
+ * the -O3 optimisation level is too aggressive and causes issues for the guest
+ * VM. Hence, instead of using -O3 we use -O2 to avoid the issue. */
+#ifdef NDEBUG
+#pragma GCC optimize ("O2")
+#endif
+
 #include <sel4/sel4.h>
 
 #include <sel4vm/guest_vm.h>