new library stubs

Author: jsinglet

cpp/common/src/codingstandards/cpp/Concurrency.qll

@@ -876,3 +876,45 @@ predicate getAThreadSpecificStorageDeallocationCall(C11ThreadCreateCall tcc, Dea
     DataFlow::localFlow(DataFlow::exprNode(tsg), DataFlow::exprNode(dexp.getFreedExpr()))
   )
 }
+
+/**
+ * Models calls to routines `atomic_compare_exchange_weak` and
+ * `atomic_compare_exchange_weak_explicit` in the `stdatomic` library.
+ * Note that these are typically implemented as macros within Clang and
+ * GCC's standard libraries.
+ */
+class AtomicCompareExchange extends MacroInvocation {
+  AtomicCompareExchange() {
+    getMacroName() = "atomic_compare_exchange_weak"
+    or
+    // some compilers model `atomic_compare_exchange_weak` as a macro that
+    // expands to `atomic_compare_exchange_weak_explicit` so this defeats that
+    // and other similar modeling.
+    getMacroName() = "atomic_compare_exchange_weak_explicit" and
+    not exists(MacroInvocation m |
+      m.getMacroName() = "atomic_compare_exchange_weak" and
+      m.getAnExpandedElement() = getAnExpandedElement()
+    )
+  }
+}
+
+/**
+ * Models calls to routines `atomic_store` and
+ * `atomic_store_explicit` in the `stdatomic` library.
+ * Note that these are typically implemented as macros within Clang and
+ * GCC's standard libraries.
+ */
+class AtomicStore extends MacroInvocation {
+  AtomicStore() {
+    getMacroName() = "atomic_store"
+    or
+    // some compilers model `atomic_compare_exchange_weak` as a macro that
+    // expands to `atomic_compare_exchange_weak_explicit` so this defeats that
+    // and other similar modeling.
+    getMacroName() = "atomic_store_explicit" and
+    not exists(MacroInvocation m |
+      m.getMacroName() = "atomic_store" and
+      m.getAnExpandedElement() = getAnExpandedElement()
+    )
+  }
+}