Add volatile to asm statement in intr_get_level(),

otherwise GCC will assume that two calls to this function can be
optimized into one, even across asm("sti") or asm("cli").

diff --git a/src/threads/interrupt.c b/src/threads/interrupt.c
index 8e7d575afe7928ac5f22c57c11719e2107dcae50..3637b0013edd9c92f347f23f60e230ec00efcfbc 100644 (file)
--- a/src/threads/interrupt.c
+++ b/src/threads/interrupt.c
@@ -51,7 +51,7 @@ intr_get_level (void)
 {
   uint32_t flags;
   
-  asm ("pushfl; popl %0" : "=g" (flags));
+  asm volatile ("pushfl; popl %0" : "=g" (flags));
 
   return flags & FLAG_IF ? INTR_ON : INTR_OFF;
 }