[analyzer] Add system header simulator a symmetric random access iterator operator+

Summary:
Random access iterators must handle operator+, where the iterator is on the
RHS. The system header simulator library is extended with these operators.

Reviewers: Szelethus

Subscribers: whisperity, xazax.hun, baloghadamsoftware, szepet, a.sidorin, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, Charusso, steakhal, martong, ASDenysPetrov, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83226

clang/test/Analysis/Inputs/system-header-simulator-cxx.h

@@ -60,6 +60,11 @@ template <typename T, typename Ptr, typename Ref> struct __vector_iterator {
   __vector_iterator<T, Ptr, Ref> operator+(difference_type n) {
     return ptr + n;
   }
+  friend __vector_iterator<T, Ptr, Ref> operator+(
+      difference_type n,
+      const __vector_iterator<T, Ptr, Ref> &iter) {
+    return n + iter.ptr;
+  }
   __vector_iterator<T, Ptr, Ref> operator-(difference_type n) {
     return ptr - n;
   }
@@ -118,6 +123,11 @@ template <typename T, typename Ptr, typename Ref> struct __deque_iterator {
   __deque_iterator<T, Ptr, Ref> operator+(difference_type n) {
     return ptr + n;
   }
+  friend __deque_iterator<T, Ptr, Ref> operator+(
+      difference_type n,
+      const __deque_iterator<T, Ptr, Ref> &iter) {
+    return n + iter.ptr;
+  }
   __deque_iterator<T, Ptr, Ref> operator-(difference_type n) {
     return ptr - n;
   }

clang/test/Analysis/diagnostics/explicit-suppression.cpp

@@ -19,6 +19,6 @@ class C {
 void testCopyNull(C *I, C *E) {
   std::copy(I, E, (C *)0);
 #ifndef SUPPRESSED
-  // expected-warning@../Inputs/system-header-simulator-cxx.h:699 {{Called C++ object pointer is null}}
+  // expected-warning@../Inputs/system-header-simulator-cxx.h:709 {{Called C++ object pointer is null}}
 #endif
 }