Change treatment plain char type and CV qualified integer types.

The plain char type can hold numeric data, but is frequently used to
hold character data. To be able to support the case where a plain char
type holds character data we split the rule into two queries. One
considering all the variable width integer types excluding the plain
char type and one considering just the plain char type. This allows for
deviation on the second case.

Additionally, the original query wasn't considering CV qualified
variable with integer types. Those are now included.

change_notes/2024-01-12-fix-reported-fp-a3-9-1.md

@@ -0,0 +1,5 @@
+- `A3-9-1` - `VariableWidthIntegerTypesUsed.ql`:
+    - Exclude the plain char type. Still includes `signed char` and `unsigned char`.
+    - Include CV-qualified variable width integer types.
+- `A3-9-1` - `VariableWidthPlainCharTypeUsed.ql`:
+    - New query to support fine grained deviation support for the plain char type.

cpp/autosar/src/rules/A3-9-1/VariableWidthIntegerTypesUsed.ql

@@ -1,8 +1,8 @@
 /**
  * @id cpp/autosar/variable-width-integer-types-used
  * @name A3-9-1: Use fixed-width integer types instead of basic, variable-width, integer types
- * @description The basic numerical types of char, int, short, long are not supposed to be used. The
- *              specific-length types from <cstdint> header need be used instead.
+ * @description The basic numerical types of signed/unsigned char, int, short, long are not supposed
+ *              to be used. The specific-length types from <cstdint> header need be used instead.
  * @kind problem
  * @precision very-high
  * @problem.severity error
@@ -19,15 +19,17 @@ import cpp
 import codingstandards.cpp.autosar
 import codingstandards.cpp.EncapsulatingFunctions
 import codingstandards.cpp.BuiltInNumericTypes
+import codingstandards.cpp.Type
 
-from Variable v
+
+from Variable v, Type typeStrippedOfSpecifiers
 where
   not isExcluded(v, DeclarationsPackage::variableWidthIntegerTypesUsedQuery()) and
+  typeStrippedOfSpecifiers = stripSpecifiers(v.getType()) and
   (
-    v.getType() instanceof BuiltInIntegerType or
-    v.getType() instanceof PlainCharType or
-    v.getType() instanceof UnsignedCharType or
-    v.getType() instanceof SignedCharType
+    typeStrippedOfSpecifiers instanceof BuiltInIntegerType or
+    typeStrippedOfSpecifiers instanceof UnsignedCharType or
+    typeStrippedOfSpecifiers instanceof SignedCharType
   ) and
   not v instanceof ExcludedVariable
 select v, "Variable '" + v.getName() + "' has variable-width type."

cpp/autosar/src/rules/A3-9-1/VariableWidthPlainCharTypeUsed.ql

@@ -0,0 +1,26 @@
+/**
+ * @id cpp/autosar/variable-width-plain-char-types-used
+ * @name A3-9-1: Use a fixed-width integer type instead of a char type
+ * @description The basic numerical type char is not supposed to be used. The specific-length types
+ *              from <cstdint> header need be used instead.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity error
+ * @tags external/autosar/id/a3-9-1
+ *       correctness
+ *       security
+ *       maintainability
+ *       external/autosar/allocated-target/implementation
+ *       external/autosar/enforcement/automated
+ *       external/autosar/obligation/required
+ */
+
+import cpp
+import codingstandards.cpp.autosar
+import codingstandards.cpp.Type
+
+from Variable variable
+where
+  not isExcluded(variable, DeclarationsPackage::variableWidthPlainCharTypeUsedQuery()) and
+  stripSpecifiers(variable.getType()) instanceof PlainCharType
+select variable, "Variable '" + variable.getName() + "' has variable-width char type."

cpp/autosar/test/rules/A3-9-1/VariableWidthIntegerTypesUsed.expected

@@ -1,4 +1,3 @@
-| test.cpp:4:8:4:8 | c | Variable 'c' has variable-width type. |
 | test.cpp:5:17:5:18 | uc | Variable 'uc' has variable-width type. |
 | test.cpp:6:15:6:16 | sc | Variable 'sc' has variable-width type. |
 | test.cpp:8:7:8:7 | i | Variable 'i' has variable-width type. |
@@ -12,3 +11,29 @@
 | test.cpp:18:8:18:8 | l | Variable 'l' has variable-width type. |
 | test.cpp:19:17:19:18 | ul | Variable 'ul' has variable-width type. |
 | test.cpp:20:15:20:16 | sl | Variable 'sl' has variable-width type. |
+| test.cpp:39:23:39:25 | uc1 | Variable 'uc1' has variable-width type. |
+| test.cpp:40:21:40:23 | sc1 | Variable 'sc1' has variable-width type. |
+| test.cpp:42:13:42:14 | i1 | Variable 'i1' has variable-width type. |
+| test.cpp:43:22:43:24 | ui1 | Variable 'ui1' has variable-width type. |
+| test.cpp:44:18:44:19 | u1 | Variable 'u1' has variable-width type. |
+| test.cpp:45:20:45:22 | si1 | Variable 'si1' has variable-width type. |
+| test.cpp:46:16:46:17 | s1 | Variable 's1' has variable-width type. |
+| test.cpp:48:15:48:17 | sh1 | Variable 'sh1' has variable-width type. |
+| test.cpp:49:24:49:27 | ush1 | Variable 'ush1' has variable-width type. |
+| test.cpp:50:22:50:25 | ssh1 | Variable 'ssh1' has variable-width type. |
+| test.cpp:52:14:52:15 | l1 | Variable 'l1' has variable-width type. |
+| test.cpp:53:23:53:25 | ul1 | Variable 'ul1' has variable-width type. |
+| test.cpp:54:21:54:23 | sl1 | Variable 'sl1' has variable-width type. |
+| test.cpp:57:26:57:28 | uc2 | Variable 'uc2' has variable-width type. |
+| test.cpp:58:24:58:26 | sc2 | Variable 'sc2' has variable-width type. |
+| test.cpp:60:16:60:17 | i2 | Variable 'i2' has variable-width type. |
+| test.cpp:61:25:61:27 | ui2 | Variable 'ui2' has variable-width type. |
+| test.cpp:62:21:62:22 | u2 | Variable 'u2' has variable-width type. |
+| test.cpp:63:23:63:25 | si2 | Variable 'si2' has variable-width type. |
+| test.cpp:64:19:64:20 | s2 | Variable 's2' has variable-width type. |
+| test.cpp:66:18:66:20 | sh2 | Variable 'sh2' has variable-width type. |
+| test.cpp:67:27:67:30 | ush2 | Variable 'ush2' has variable-width type. |
+| test.cpp:68:25:68:28 | ssh2 | Variable 'ssh2' has variable-width type. |
+| test.cpp:70:17:70:18 | l2 | Variable 'l2' has variable-width type. |
+| test.cpp:71:26:71:28 | ul2 | Variable 'ul2' has variable-width type. |
+| test.cpp:72:24:72:26 | sl2 | Variable 'sl2' has variable-width type. |

cpp/autosar/test/rules/A3-9-1/VariableWidthPlainCharTypeUsed.expected

@@ -0,0 +1,3 @@
+| test.cpp:4:8:4:8 | c | Variable 'c' has variable-width char type. |
+| test.cpp:38:14:38:15 | c1 | Variable 'c1' has variable-width char type. |
+| test.cpp:56:17:56:18 | c2 | Variable 'c2' has variable-width char type. |

cpp/autosar/test/rules/A3-9-1/VariableWidthPlainCharTypeUsed.qlref

@@ -0,0 +1 @@
+rules/A3-9-1/VariableWidthPlainCharTypeUsed.ql

cpp/autosar/test/rules/A3-9-1/test.cpp

@@ -32,4 +32,42 @@ void test_variable_width_type_variables() {
 
 int main(int argc, char *argv[]) { // COMPLIANT
   // main as an exception
+}
+
+void test_variable_width_type_qualified_variables() {
+  const char c1 = 0;           // NON_COMPLIANT
+  const unsigned char uc1 = 0; // NON_COMPLIANT
+  const signed char sc1 = 0;   // NON_COMPLIANt
+
+  const int i1 = 0;           // NON_COMPLIANT
+  const unsigned int ui1 = 0; // NON_COMPLIANT
+  const unsigned u1 = 0;      // NON_COMPLIANT
+  const signed int si1 = 0;   // NON_COMPLIANT
+  const signed s1 = 0;        // NON_COMPLIANT
+
+  const short sh1 = 0;           // NON_COMPLIANT
+  const unsigned short ush1 = 0; // NON_COMPLIANT
+  const signed short ssh1 = 0;   // NON_COMPLIANT
+
+  const long l1 = 0;           // NON_COMPLIANT
+  const unsigned long ul1 = 0; // NON_COMPLIANT
+  const signed long sl1 = 0;   // NON_COMPLIANT
+
+  volatile char c2;           // NON_COMPLIANT
+  volatile unsigned char uc2; // NON_COMPLIANT
+  volatile signed char sc2;   // NON_COMPLIANt
+
+  volatile int i2;           // NON_COMPLIANT
+  volatile unsigned int ui2; // NON_COMPLIANT
+  volatile unsigned u2;      // NON_COMPLIANT
+  volatile signed int si2;   // NON_COMPLIANT
+  volatile signed s2;        // NON_COMPLIANT
+
+  volatile short sh2;           // NON_COMPLIANT
+  volatile unsigned short ush2; // NON_COMPLIANT
+  volatile signed short ssh2;   // NON_COMPLIANT
+
+  volatile long l2;           // NON_COMPLIANT
+  volatile unsigned long ul2; // NON_COMPLIANT
+  volatile signed long sl2;   // NON_COMPLIANT
 }

cpp/common/src/codingstandards/cpp/Type.qll

@@ -22,3 +22,12 @@ class FundamentalType extends BuiltInType {
 class IncompleteType extends Class {
   IncompleteType() { not hasDefinition() }
 }
+
+/**
+ * A type without `const` and `volatile` specifiers.
+ */
+Type stripSpecifiers(Type type) {
+  if type instanceof SpecifiedType
+  then result = stripSpecifiers(type.(SpecifiedType).getBaseType())
+  else result = type
+}

cpp/common/src/codingstandards/cpp/exclusions/cpp/Declarations.qll

@@ -9,6 +9,7 @@ newtype DeclarationsQuery =
   TGlobalSizedOperatorDeleteNotDefinedQuery() or
   TGlobalUnsizedOperatorDeleteNotDefinedQuery() or
   TVariableWidthIntegerTypesUsedQuery() or
+  TVariableWidthPlainCharTypeUsedQuery() or
   TAutoSpecifierNotUsedAppropriatelyInFunctionDefinitionQuery() or
   TAutoSpecifierNotUsedAppropriatelyInVariableDefinitionQuery() or
   TIdentifierDeclarationAndInitializationNotOnSeparateLinesQuery() or
@@ -68,6 +69,15 @@ predicate isDeclarationsQueryMetadata(Query query, string queryId, string ruleId
   ruleId = "A3-9-1" and
   category = "required"
   or
+  query =
+    // `Query` instance for the `variableWidthPlainCharTypeUsed` query
+    DeclarationsPackage::variableWidthPlainCharTypeUsedQuery() and
+  queryId =
+    // `@id` for the `variableWidthPlainCharTypeUsed` query
+    "cpp/autosar/variable-width-plain-char-type-used" and
+  ruleId = "A3-9-1" and
+  category = "required"
+  or
   query =
     // `Query` instance for the `autoSpecifierNotUsedAppropriatelyInFunctionDefinition` query
     DeclarationsPackage::autoSpecifierNotUsedAppropriatelyInFunctionDefinitionQuery() and
@@ -213,6 +223,13 @@ module DeclarationsPackage {
       TQueryCPP(TDeclarationsPackageQuery(TVariableWidthIntegerTypesUsedQuery()))
   }
 
+  Query variableWidthPlainCharTypeUsedQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `variableWidthPlainCharTypeUsed` query
+      TQueryCPP(TDeclarationsPackageQuery(TVariableWidthPlainCharTypeUsedQuery()))
+  }
+
   Query autoSpecifierNotUsedAppropriatelyInFunctionDefinitionQuery() {
     //autogenerate `Query` type
     result =

rule_packages/cpp/Declarations.json

@@ -78,12 +78,28 @@
       },
       "queries": [
         {
-          "description": "The basic numerical types of char, int, short, long are not supposed to be used. The specific-length types from <cstdint> header need be used instead.",
+          "description": "The basic numerical types of signed/unsigned char, int, short, long are not supposed to be used. The specific-length types from <cstdint> header need be used instead.",
           "kind": "problem",
           "name": "Use fixed-width integer types instead of basic, variable-width, integer types",
           "precision": "very-high",
           "severity": "error",
           "short_name": "VariableWidthIntegerTypesUsed",
+          "tags": [
+            "correctness",
+            "security",
+            "maintainability"
+          ],
+          "implementation_scope": {
+            "description": "This implementation excludes the plain char type from consideration."
+          }
+        },
+        {
+          "description": "The basic numerical type char is not supposed to be used. The specific-length types from <cstdint> header need be used instead.",
+          "kind": "problem",
+          "name": "Use a fixed-width integer type instead of a char type",
+          "precision": "very-high",
+          "severity": "error",
+          "short_name": "VariableWidthPlainCharTypeUsed",
           "tags": [
             "correctness",
             "security",