Declarations6: add RULE-8-11

Author: knewbury01

c/misra/src/rules/RULE-8-11/ArrayExternalLinkageSizeExplicitlySpecified.ql

@@ -0,0 +1,28 @@
+/**
+ * @id c/misra/array-external-linkage-size-explicitly-specified
+ * @name RULE-8-11: When an array with external linkage is declared, its size should be explicitly specified
+ * @description Declaring an array without an explicit size disallows the compiler and static
+ *              checkers from doing array bounds analysis and can lead to less readable, unsafe
+ *              code.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity error
+ * @tags external/misra/id/rule-8-11
+ *       correctness
+ *       readability
+ *       external/misra/obligation/advisory
+ */
+
+import cpp
+import codingstandards.c.misra
+import codingstandards.cpp.Identifiers
+
+from VariableDeclarationEntry v, ArrayType t
+where
+  not isExcluded(v, Declarations6Package::arrayExternalLinkageSizeExplicitlySpecifiedQuery()) and
+  v.getDeclaration() instanceof ExternalIdentifiers and
+  v.getType() = t and
+  not exists(t.getSize()) and
+  //this rule applies to non-defining declarations only
+  not v.isDefinition()
+select v, "Array declared without explicit size."

c/misra/test/rules/RULE-8-11/ArrayExternalLinkageSizeExplicitlySpecified.expected

@@ -0,0 +1 @@
+| test.c:2:12:2:13 | declaration of a1 | Array declared without explicit size. |

c/misra/test/rules/RULE-8-11/ArrayExternalLinkageSizeExplicitlySpecified.qlref

@@ -0,0 +1 @@
+rules/RULE-8-11/ArrayExternalLinkageSizeExplicitlySpecified.ql

c/misra/test/rules/RULE-8-11/test.c

@@ -0,0 +1,6 @@
+extern int a[1]; // COMPLIANT
+extern int a1[]; // NON_COMPLIANT
+extern int a2[] = {
+    1}; // COMPLIANT - this rule applies to non-defining declarations only
+static int a3[]; // COMPLIANT - not external linkage
+int a4[];        // COMPLIANT - is a definition

cpp/common/src/codingstandards/cpp/exclusions/c/Declarations6.qll

@@ -6,7 +6,8 @@ import codingstandards.cpp.exclusions.RuleMetadata
 newtype Declarations6Query =
   TFunctionDeclaredImplicitlyQuery() or
   TIdentifiersWithExternalLinkageNotUniqueQuery() or
-  TIdentifiersWithInternalLinkageNotUniqueQuery()
+  TIdentifiersWithInternalLinkageNotUniqueQuery() or
+  TArrayExternalLinkageSizeExplicitlySpecifiedQuery()
 
 predicate isDeclarations6QueryMetadata(Query query, string queryId, string ruleId, string category) {
   query =
@@ -35,6 +36,15 @@ predicate isDeclarations6QueryMetadata(Query query, string queryId, string ruleI
     "c/misra/identifiers-with-internal-linkage-not-unique" and
   ruleId = "RULE-5-9" and
   category = "advisory"
+  or
+  query =
+    // `Query` instance for the `arrayExternalLinkageSizeExplicitlySpecified` query
+    Declarations6Package::arrayExternalLinkageSizeExplicitlySpecifiedQuery() and
+  queryId =
+    // `@id` for the `arrayExternalLinkageSizeExplicitlySpecified` query
+    "c/misra/array-external-linkage-size-explicitly-specified" and
+  ruleId = "RULE-8-11" and
+  category = "advisory"
 }
 
 module Declarations6Package {
@@ -58,4 +68,11 @@ module Declarations6Package {
       // `Query` type for `identifiersWithInternalLinkageNotUnique` query
       TQueryC(TDeclarations6PackageQuery(TIdentifiersWithInternalLinkageNotUniqueQuery()))
   }
+
+  Query arrayExternalLinkageSizeExplicitlySpecifiedQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `arrayExternalLinkageSizeExplicitlySpecified` query
+      TQueryC(TDeclarations6PackageQuery(TArrayExternalLinkageSizeExplicitlySpecifiedQuery()))
+  }
 }

rule_packages/c/Declarations6.json

@@ -59,6 +59,26 @@
         }
       ],
       "title": "Identifiers that define objects or functions with internal linkage should be unique"
+    },
+    "RULE-8-11": {
+      "properties": {
+        "obligation": "advisory"
+      },
+      "queries": [
+        {
+          "description": "Declaring an array without an explicit size disallows the compiler and static checkers from doing array bounds analysis and can lead to less readable, unsafe code.",
+          "kind": "problem",
+          "name": "When an array with external linkage is declared, its size should be explicitly specified",
+          "precision": "very-high",
+          "severity": "error",
+          "short_name": "ArrayExternalLinkageSizeExplicitlySpecified",
+          "tags": [
+            "correctness",
+            "readability"
+          ]
+        }
+      ],
+      "title": "When an array with external linkage is declared, its size should be explicitly specified"
     }
   }
 }

rules.csv

@@ -656,7 +656,7 @@ c,MISRA-C-2012,RULE-8-7,Yes,Advisory,,,Functions and objects should not be defin
 c,MISRA-C-2012,RULE-8-8,Yes,Required,,,The static storage class specifier shall be used in all declarations of objects and functions that have internal linkage,M3-3-2,Declarations,Medium,
 c,MISRA-C-2012,RULE-8-9,Yes,Advisory,,,An object should be defined at block scope if its identifier only appears in a single function,M3-4-1,Declarations,Medium,
 c,MISRA-C-2012,RULE-8-10,Yes,Required,,,An inline function shall be declared with the static storage class,,Declarations,Medium,
-c,MISRA-C-2012,RULE-8-11,Yes,Advisory,,,"When an array with external linkage is declared, its size should be explicitly specified",,Declarations,Medium,
+c,MISRA-C-2012,RULE-8-11,Yes,Advisory,,,"When an array with external linkage is declared, its size should be explicitly specified",,Declarations6,Medium,
 c,MISRA-C-2012,RULE-8-12,Yes,Required,,,"Within an enumerator list, the value of an implicitly-specified enumeration constant shall be unique",,Declarations,Medium,
 c,MISRA-C-2012,RULE-8-13,Yes,Advisory,,,A pointer should point to a const-qualified type whenever possible,,Pointers1,Medium,
 c,MISRA-C-2012,RULE-8-14,Yes,Required,,,The restrict type qualifier shall not be used,,Banned,Easy,