[modules] Treat friend declarations that are lexically within a dependent

context as anonymous for merging purposes. They can't be found by their names,
so we merge them based on their position within the surrounding context.

llvm-svn: 228485

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTCommon.h b/clang/lib/Serialization/ASTCommon.h
index 38a0ff5fbd4..88cdbcfe179 100644
--- a/clang/lib/Serialization/ASTCommon.h
+++ b/clang/lib/Serialization/ASTCommon.h
@@ -15,6 +15,7 @@
 #define LLVM_CLANG_LIB_SERIALIZATION_ASTCOMMON_H
 
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclFriend.h"
 #include "clang/Serialization/ASTBitCodes.h"
 
 namespace clang {
@@ -85,6 +86,24 @@ bool isRedeclarableDeclKind(unsigned Kind);
 /// declaration number.
 bool needsAnonymousDeclarationNumber(const NamedDecl *D);
 
+/// \brief Visit each declaration within \c DC that needs an anonymous
+/// declaration number and call \p Visit with the declaration and its number.
+template<typename Fn> void numberAnonymousDeclsWithin(const DeclContext *DC,
+                                                      Fn Visit) {
+  unsigned Index = 0;
+  for (Decl *LexicalD : DC->decls()) {
+    // For a friend decl, we care about the declaration within it, if any.
+    if (auto *FD = dyn_cast<FriendDecl>(LexicalD))
+      LexicalD = FD->getFriendDecl();
+
+    auto *ND = dyn_cast_or_null<NamedDecl>(LexicalD);
+    if (!ND || !needsAnonymousDeclarationNumber(ND))
+      continue;
+
+    Visit(ND, Index++);
+  }
+}
+
 } // namespace serialization
 
 } // namespace clang