Merge branch 'main' into knewbury01/Declarations3

Author: knewbury01

change_notes/2022-08-18-dead-code-static-asserts.md

@@ -0,0 +1,2 @@
+ - `M0-1-9` - `DeadCode.ql`:
+   - More compiler generated statements are now excluded from being reported as dead code, including compiler generated statements for `static_assert` calls.

change_notes/2022-08-18-variable-templates-reused-name.md

@@ -0,0 +1,2 @@
+ - `A2-10-5` - `IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.ql`
+   - Reduce false positives by excluding variable template instantiations.

change_notes/2022-09-18-m3-2-1-templates.md

@@ -0,0 +1,4 @@
+ - `M3-2-1` - `DeclarationsOfAnObjectShallHaveCompatibleTypes.ql`
+   - Reduced false positives by excluding non-object variables (for example, member variables).
+   - Reduced false positives by excluding variable templates and template instantiations.
+   - Improved the reported error message by including the conflicting type names.

cpp/autosar/src/rules/A2-10-5/IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.ql

@@ -32,7 +32,11 @@ where
   not isExcluded(o2,
     NamingPackage::identifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReusedQuery()) and
   not o1 = o2 and
-  o1.getName() = o2.getName()
+  o1.getName() = o2.getName() and
+  // Only consider variables from uninstantiated templates, to avoid false positives where o1 and
+  // o2 are the same object across different template instantiations
+  not o1.isFromTemplateInstantiation(_) and
+  not o2.isFromTemplateInstantiation(_)
 select o2,
   "Identifier name of non-member object $@ reuses the identifier name of non-member object $@.", o2,
   o2.getName(), o1, o1.getName()

cpp/autosar/src/rules/M0-1-9/DeadCode.ql

@@ -51,7 +51,9 @@ predicate isDeadStmt(Stmt s) {
   // - The initializers for each of the variables are pure
   exists(DeclStmt ds |
     ds = s and
-    forall(Declaration d | d = ds.getADeclaration() |
+    // Use forex so that we don't flag "fake" generated `DeclStmt`s (e.g. those generated by the
+    // extractor for static_asserts) with no actual declarations
+    forex(Declaration d | d = ds.getADeclaration() |
       exists(LocalScopeVariable v |
         d = v and
         v.getInitializer().getExpr().isPure() and
@@ -123,5 +125,7 @@ where
   // output". We therefore exclude unreachable statements as they are, by definition, not executed.
   not s.getBasicBlock() = any(UnreachableBasicBlock ubb).getABasicBlock() and
   // Exclude code generated by macros, because the code may be "live" in other instantiations
-  not s.isAffectedByMacro()
+  not s.isAffectedByMacro() and
+  // Exclude compiler generated statements
+  not s.isCompilerGenerated()
 select s, "This statement is dead code."

cpp/autosar/src/rules/M3-2-1/DeclarationsOfAnObjectShallHaveCompatibleTypes.ql

@@ -20,13 +20,23 @@ import cpp
 import codingstandards.cpp.autosar
 import codingstandards.cpp.Typehelpers
 
+predicate isNonTemplateObjectVariable(GlobalOrNamespaceVariable gv) {
+  not gv.isFromTemplateInstantiation(_) and
+  not gv.isFromUninstantiatedTemplate(_)
+}
+
 from VariableDeclarationEntry decl1, VariableDeclarationEntry decl2
 where
   not isExcluded(decl1, DeclarationsPackage::declarationsOfAnObjectShallHaveCompatibleTypesQuery()) and
   not isExcluded(decl2, DeclarationsPackage::declarationsOfAnObjectShallHaveCompatibleTypesQuery()) and
   not areCompatible(decl1.getType(), decl2.getType()) and
   // Note that normally `VariableDeclarationEntry` includes parameters, which are not covered
   // by this query. We implicitly exclude them with the `getQualifiedName()` predicate.
-  decl1.getVariable().getQualifiedName() = decl2.getVariable().getQualifiedName()
-select decl1, "The object $@ is not compatible with re-declaration $@", decl1, decl1.getName(),
-  decl2, decl2.getName()
+  decl1.getVariable().getQualifiedName() = decl2.getVariable().getQualifiedName() and
+  // Only consider global/namespace variables which aren't templated
+  isNonTemplateObjectVariable(decl1.getVariable()) and
+  isNonTemplateObjectVariable(decl2.getVariable())
+select decl1,
+  "The object $@ of type " + decl1.getType().toString() +
+    " is not compatible with re-declaration $@ of type " + decl2.getType().toString(), decl1,
+  decl1.getName(), decl2, decl2.getName()

cpp/autosar/test/rules/A2-10-5/IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.expected

@@ -1,2 +1,4 @@
 | test1a.cpp:6:12:6:13 | g3 | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1a.cpp:6:12:6:13 | g3 | g3 | test1b.cpp:7:12:7:13 | g3 | g3 |
+| test1a.cpp:17:43:17:43 | number_two | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1a.cpp:17:43:17:43 | number_two | number_two | test1b.cpp:12:43:12:43 | number_two | number_two |
 | test1b.cpp:7:12:7:13 | g3 | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1b.cpp:7:12:7:13 | g3 | g3 | test1a.cpp:6:12:6:13 | g3 | g3 |
+| test1b.cpp:12:43:12:43 | number_two | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1b.cpp:12:43:12:43 | number_two | number_two | test1a.cpp:17:43:17:43 | number_two | number_two |

cpp/autosar/test/rules/A2-10-5/test1a.cpp

@@ -5,3 +5,17 @@ static int g1 = 0;
 static int g2;      // COMPLIANT
 static int g3 = 1;  // NON_COMPLIANT
 static void f1(){}; // NON_COMPLIANT
+
+// Variable template has multiple declarations: one for the uninstantiated
+// template and one for each instantiation
+template <class T> constexpr T number_one = T(1); // COMPLIANT
+
+int test() { return number_one<int>; }
+
+long test2() { return number_one<long>; }
+
+template <class T> constexpr T number_two = T(1); // NON_COMPLIANT
+
+int test3() { return number_two<int>; }
+
+long test4() { return number_two<long>; }

cpp/autosar/test/rules/A2-10-5/test1b.cpp

@@ -8,3 +8,9 @@ static int g3 = 0; // NON_COMPLIANT
 }
 
 static void f1() {} // NON_COMPLIANT
+
+template <class T> constexpr T number_two = T(1); // NON_COMPLIANT
+
+int test3() { return number_two<int>; }
+
+long test4() { return number_two<long>; }

cpp/autosar/test/rules/M0-1-9/test.cpp

@@ -76,5 +76,7 @@ int test_dead_code(int x) {
   } catch (...) {   // NON_COMPLIANT
   }
 
+  static_assert(1); // COMPLIANT
+
   return live5 + live6; // COMPLIANT
 }