release/20.x: [clang] StmtPrinter: Handle DeclRefExpr to a Decomposition (#125001)

clang/lib/AST/StmtPrinter.cpp

@@ -1291,8 +1291,14 @@ void StmtPrinter::VisitDeclRefExpr(DeclRefExpr *Node) {
          << PD->getFunctionScopeIndex();
       break;
     }
+    case Decl::Decomposition:
+      OS << "decomposition";
+      for (const auto &I : cast<DecompositionDecl>(VD)->bindings())
+        OS << '-' << I->getName();
+      break;
     default:
-      llvm_unreachable("Unhandled anonymous declaration kind");
+      OS << "unhandled-anonymous-" << VD->getDeclKindName();
+      break;
     }
   }
   if (Node->hasExplicitTemplateArgs()) {

clang/test/Analysis/anonymous-decls.cpp

@@ -0,0 +1,89 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.DumpCFG -triple x86_64-apple-darwin12 -std=c++20 %s 2>&1 | FileCheck %s
+
+struct A {
+  static A a;
+  char b;
+  friend bool operator==(A, A) = default;
+};
+bool _ = A() == A::a;
+
+// FIXME: steps 1 and 5 show anonymous function parameters are
+// not handled correctly.
+
+// CHECK-LABEL: bool operator==(A, A) noexcept = default
+// CHECK-NEXT: [B2 (ENTRY)]
+// CHECK-NEXT:    Succs (1): B1
+// CHECK:      [B1]
+// CHECK-NEXT:    1: function-parameter-0-0
+// CHECK-NEXT:    2: [B1.1].b
+// CHECK-NEXT:    3: [B1.2] (ImplicitCastExpr, LValueToRValue, char)
+// CHECK-NEXT:    4: [B1.3] (ImplicitCastExpr, IntegralCast, int)
+// CHECK-NEXT:    5: function-parameter-0-1
+// CHECK-NEXT:    6: [B1.5].b
+// CHECK-NEXT:    7: [B1.6] (ImplicitCastExpr, LValueToRValue, char)
+// CHECK-NEXT:    8: [B1.7] (ImplicitCastExpr, IntegralCast, int)
+// CHECK-NEXT:    9: [B1.4] == [B1.8]
+// CHECK-NEXT:   10: return [B1.9];
+// CHECK-NEXT:    Preds (1): B2
+// CHECK-NEXT:    Succs (1): B0
+// CHECK:      [B0 (EXIT)]
+// CHECK-NEXT:    Preds (1): B1
+
+namespace std {
+template <class> struct iterator_traits;
+template <class, class> struct pair;
+template <class _Tp> struct iterator_traits<_Tp *> {
+  typedef _Tp &reference;
+};
+template <long, class> struct tuple_element;
+template <class> struct tuple_size;
+template <class _T1, class _T2> struct tuple_size<pair<_T1, _T2>> {
+  static const int value = 2;
+};
+template <class _T1, class _T2> struct tuple_element<0, pair<_T1, _T2>> {
+  using type = _T1;
+};
+template <class _T1, class _T2> struct tuple_element<1, pair<_T1, _T2>> {
+  using type = _T2;
+};
+template <long _Ip, class _T1, class _T2>
+tuple_element<_Ip, pair<_T1, _T2>>::type get(pair<_T1, _T2> &);
+struct __wrap_iter {
+  iterator_traits<pair<int, int> *>::reference operator*();
+  void operator++();
+};
+bool operator!=(__wrap_iter, __wrap_iter);
+struct vector {
+  __wrap_iter begin();
+  __wrap_iter end();
+};
+} // namespace std
+int main() {
+  std::vector v;
+  for (auto &[a, b] : v)
+    ;
+}
+
+// FIXME: On steps 8 and 14, a decomposition is referred by name, which they never have.
+
+// CHECK-LABEL: int main()
+// CHECK:      [B3]
+// CHECK-NEXT:   1: operator*
+// CHECK-NEXT:   2: [B3.1] (ImplicitCastExpr, FunctionToPointerDecay, iterator_traits<pair<int, int> *>::reference (*)(void))
+// CHECK-NEXT:   3: __begin1
+// CHECK-NEXT:   4: * [B3.3] (OperatorCall)
+// CHECK-NEXT:   5: auto &;
+// CHECK-NEXT:   6: get<0UL>
+// CHECK-NEXT:   7: [B3.6] (ImplicitCastExpr, FunctionToPointerDecay, typename tuple_element<0L, pair<int, int> >::type (*)(pair<int, int> &))
+// CHECK-NEXT:   8: decomposition-a-b
+// CHECK-NEXT:   9: [B3.7]([B3.8])
+// CHECK-NEXT:  10: [B3.9]
+// CHECK-NEXT:  11: std::tuple_element<0, std::pair<int, int>>::type a = get<0UL>(decomposition-a-b);
+// CHECK-NEXT:  12: get<1UL>
+// CHECK-NEXT:  13: [B3.12] (ImplicitCastExpr, FunctionToPointerDecay, typename tuple_element<1L, pair<int, int> >::type (*)(pair<int, int> &))
+// CHECK-NEXT:  14: decomposition-a-b
+// CHECK-NEXT:  15: [B3.13]([B3.14])
+// CHECK-NEXT:  16: [B3.15]
+// CHECK-NEXT:  17: std::tuple_element<1, std::pair<int, int>>::type b = get<1UL>(decomposition-a-b);
+// CHECK-NEXT:   Preds (1): B1
+// CHECK-NEXT:   Succs (1): B2