C++: Support __has_unique_object_representations builtin

Author: jketema

cpp/ql/lib/semmle/code/cpp/exprs/BuiltInOperations.qll

@@ -999,9 +999,27 @@ class BuiltInComplexOperation extends BuiltInOperation, @builtincomplex {
  * Returns `true` if the type has is an aggregate type.
  * ```
  * std::integral_constant<bool, __is_aggregate(_Tp)> ia;
- * ``` */
+ * ```
+ */
 class BuiltInOperationIsAggregate extends BuiltInOperation, @isaggregate {
   override string toString() { result = "__is_aggregate" }
 
   override string getAPrimaryQlClass() { result = "BuiltInOperationIsAggregate" }
 }
+
+/**
+ * A C++ `__has_unique_object_representations` built-in operation (used by some
+ * implementations of the `<type_traits>` header).
+ *
+ * Returns `true` if the type is trivially copyable and if the object representation
+ * is unique for two objects with the same value.
+ * ```
+ * bool v = __has_unique_object_representations(MyType);
+ * ```
+ */
+class BuiltInOperationHasUniqueObjectRepresentations extends BuiltInOperation,
+  @hasuniqueobjectrepresentations {
+  override string toString() { result = "__has_unique_object_representations" }
+
+  override string getAPrimaryQlClass() { result = "BuiltInOperationHasUniqueObjectRepresentations" }
+}

cpp/ql/lib/semmlecode.cpp.dbscheme

@@ -1652,6 +1652,7 @@ case @expr.kind of
 | 329 = @temp_init
 | 330 = @isassignable
 | 331 = @isaggregate
+| 332 = @hasuniqueobjectrepresentations
 ;
 
 @var_args_expr = @vastartexpr
@@ -1715,6 +1716,7 @@ case @expr.kind of
             | @builtincomplex
             | @isassignable
             | @isaggregate
+            | @hasuniqueobjectrepresentations
             ;
 
 new_allocated_type(

cpp/ql/test/library-tests/builtins/type_traits/expr.expected

@@ -309,3 +309,7 @@
 | ms.cpp:262:28:262:51 | a_struct |  | <none> |
 | ms.cpp:263:28:263:46 | __is_aggregate | int | 0 |
 | ms.cpp:263:28:263:46 | int |  | <none> |
+| ms.cpp:265:49:265:88 | __has_unique_object_representations | int | 1 |
+| ms.cpp:265:49:265:88 | int |  | <none> |
+| ms.cpp:266:49:266:90 | __has_unique_object_representations | float | 0 |
+| ms.cpp:266:49:266:90 | float |  | <none> |

cpp/ql/test/library-tests/builtins/type_traits/ms.cpp

@@ -261,4 +261,7 @@ void f(void) {
 
     bool b_is_aggregate1 = __is_aggregate(a_struct);
     bool b_is_aggregate2 = __is_aggregate(int);
+
+    bool b_has_unique_object_representations1 = __has_unique_object_representations(int);
+    bool b_has_unique_object_representations2 = __has_unique_object_representations(float);
 }