implement MISRA RULE-6-1

Author: jeongsoolee09

c/misra/src/rules/RULE-6-1/BitFieldsShallOnlyBeDeclaredWithAnAppropriateType.ql

@@ -13,7 +13,27 @@
 import cpp
 import codingstandards.c.misra
 
-from
+predicate isSignedOrUnsignedInt(Type type) {
+    type instanceof IntType and
+    (type.(IntegralType).isExplicitlySigned() or
+    type.(IntegralType).isExplicitlyUnsigned())
+}
+
+predicate isAppropriatePrimitive(Type type) {
+    isSignedOrUnsignedInt(type) or type instanceof BoolType
+}
+
+predicate isAppropriateTypedef(Type type) {
+    type instanceof TypedefType and
+    isAppropriatePrimitive(type.(TypedefType).resolveTypedefs())
+}
+
+predicate isInappropriateType(Type type) {
+    not (isAppropriatePrimitive(type) or isAppropriateTypedef(type))
+}
+
+from BitField bitField
 where
-  not isExcluded(x, TypesPackage::bitFieldsShallOnlyBeDeclaredWithAnAppropriateTypeQuery()) and
-select
+not isExcluded(bitField, TypesPackage::bitFieldsShallOnlyBeDeclaredWithAnAppropriateTypeQuery()) and
+ isInappropriateType(bitField.getType()) 
+select bitField, "Type " + bitField.getType() + " should not have a bit-field declaration at " + bitField + "."

c/misra/test/rules/RULE-6-1/BitFieldsShallOnlyBeDeclaredWithAnAppropriateType.expected

@@ -1 +1,4 @@
-No expected results have yet been specified
+| test.c:8:7:8:8 | b3 | Type int should not have a bit-field declaration at b3. |
+| test.c:11:15:11:16 | b5 | Type signed long should not have a bit-field declaration at b5. |
+| test.c:13:15:13:16 | b6 | Type signed char should not have a bit-field declaration at b6. |
+| test.c:14:14:14:15 | b7 | Type Color should not have a bit-field declaration at b7. |

c/misra/test/rules/RULE-6-1/test.c

@@ -0,0 +1,15 @@
+typedef unsigned int UINT_16;
+
+enum Color { R, G, B };
+
+struct SampleStruct {
+  unsigned int b1 : 2; // COMPILANT - explicitly unsigned (example in the doc)
+  signed int b2 : 2;   // COMPILANT - explicitly signed
+  int b3 : 2; // NON_COMPLIANT - plain int not permitted (example in the doc)
+  UINT_16 b4 : 2; // COMPLIANT - typedef designating unsigned int (example in
+                  // the doc)
+  signed long b5 : 2; // NON_COMPLIANT - even if long and int are the same size
+                      // (example in the doc)
+  signed char b6 : 2; // NON_COMPILANT - cannot declare bit field for char
+  enum Color b7 : 3;  // NON_COMPILANT - cannot declare bit field for enum
+} sample_struct;