Rule 21.10.1: Support other uses of va_list

Author: lcartey

cpp/misra/src/rules/RULE-21-10-1/NoVariadicFunctionMacros.ql

@@ -14,6 +14,7 @@
 
 import cpp
 import codingstandards.cpp.misra
+import codingstandards.cpp.types.Uses
 
 class VaListType extends Type {
   VaListType() {
@@ -27,15 +28,24 @@ from Element element, string message
 where
   not isExcluded(element, BannedAPIsPackage::noVariadicFunctionMacrosQuery()) and
   (
-    element.(Variable).getType() instanceof VaListType and
+    element = getATypeUse(any(VaListType vlt)) and
     (
       if element instanceof Parameter
       then
         message =
           "Declaration of parameter '" + element.(Parameter).getName() + "' of type 'va_list'."
       else
-        message =
-          "Declaration of variable '" + element.(Variable).getName() + "' of type 'va_list'."
+        if element instanceof Variable
+        then
+          message =
+            "Declaration of variable '" + element.(Variable).getName() + "' of type 'va_list'."
+        else
+          if element instanceof TypedefType
+          then
+            message =
+              "Declaration of typedef '" + element.(TypedefType).getName() +
+                "' aliasing 'va_list' type."
+          else message = "Use of 'va_list' type in an unsupported context."
     )
     or
     element instanceof BuiltInVarArgsStart and
@@ -49,9 +59,5 @@ where
     or
     element instanceof BuiltInVarArgCopy and
     message = "Call to 'va_copy'."
-    or
-    element.(TypedefType).getBaseType() instanceof VaListType and
-    message =
-      "Declaration of typedef '" + element.(TypedefType).getName() + "' aliasing 'va_list' type."
   )
 select element, message

cpp/misra/test/rules/RULE-21-10-1/NoVariadicFunctionMacros.expected

@@ -26,3 +26,4 @@
 | test.cpp:56:17:56:25 | SOME_TYPE | Declaration of typedef 'SOME_TYPE' aliasing 'va_list' type. |
 | test.cpp:58:17:58:18 | l1 | Declaration of variable 'l1' of type 'va_list'. |
 | test.cpp:59:13:59:14 | l2 | Declaration of variable 'l2' of type 'va_list'. |
+| test.cpp:65:12:65:13 | l1 | Declaration of variable 'l1' of type 'va_list'. |

cpp/misra/test/rules/RULE-21-10-1/test.cpp

@@ -57,4 +57,10 @@ typedef va_list SOME_TYPE;     // NON_COMPLIANT
 void test_va_list_alias() {
   va_list_alias l1; // NON_COMPLIANT
   SOME_TYPE l2;     // NON_COMPLIANT
+}
+
+// Note: use of va_list as a return type, or a cast, is not legal
+
+void test_va_list() {
+  va_list *l1; // NON_COMPLIANT - pointer to va_list
 }