Add VeriFast kernel queue proofs (#117)

FreeRTOS/Test/VeriFast/queue/prvIsQueueEmpty.c

@@ -0,0 +1,49 @@
+/*
+ * FreeRTOS VeriFast Proofs
+ * Copyright (C) Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "proof/queue.h"
+#define taskENTER_CRITICAL() setInterruptMask(pxQueue)
+#define taskEXIT_CRITICAL() clearInterruptMask(pxQueue)
+
+static BaseType_t prvIsQueueEmpty( const Queue_t *pxQueue )
+/*@requires [1/2]queuehandle(pxQueue, ?N, ?M, ?is_isr) &*& is_isr == false;@*/
+/*@ensures [1/2]queuehandle(pxQueue, N, M, is_isr);@*/
+{
+BaseType_t xReturn;
+
+	taskENTER_CRITICAL();
+	/*@assert queue(pxQueue, ?Storage, N, M, ?W, ?R, ?K, ?is_locked, ?abs);@*/
+	{
+		if( pxQueue->uxMessagesWaiting == ( UBaseType_t )  0 )
+		{
+			xReturn = pdTRUE;
+		}
+		else
+		{
+			xReturn = pdFALSE;
+		}
+	}
+	/*@close queue(pxQueue, Storage, N, M, W, R, K, is_locked, abs);@*/
+	taskEXIT_CRITICAL();
+
+	return xReturn;
+}