From f76b092e1a6f0df4a5c64aae3c71d6e81e4b717c Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Tue, 8 Feb 2011 19:01:05 +0000
Subject: [PATCH] Clear the linkage cache recursively.  Fixes PR8926.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125104 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/AST/Decl.h |  2 +-
 lib/AST/Decl.cpp         | 31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index f81f9d0ca4..e8431c1106 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -274,7 +274,7 @@ public:
 
   /// \brief Clear the linkage cache in response to a change
   /// to the declaration. 
-  void ClearLinkageCache() { HasCachedLinkage = 0; }
+  void ClearLinkageCache();
 
   /// \brief Looks through UsingDecls and ObjCCompatibleAliasDecls for
   /// the underlying named decl.
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 4fb47bfcdc..11614df500 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -579,6 +579,37 @@ static LinkageInfo getLVForClassMember(const NamedDecl *D, LVFlags F) {
   return LV;
 }
 
+static void clearLinkageForClass(const CXXRecordDecl *record) {
+  for (CXXRecordDecl::decl_iterator
+         i = record->decls_begin(), e = record->decls_end(); i != e; ++i) {
+    Decl *child = *i;
+    if (isa<NamedDecl>(child))
+      cast<NamedDecl>(child)->ClearLinkageCache();
+  }
+}
+
+void NamedDecl::ClearLinkageCache() {
+  // Note that we can't skip clearing the linkage of children just
+  // because the parent doesn't have cached linkage:  we don't cache
+  // when computing linkage for parent contexts.
+
+  HasCachedLinkage = 0;
+
+  // If we're changing the linkage of a class, we need to reset the
+  // linkage of child declarations, too.
+  if (const CXXRecordDecl *record = dyn_cast<CXXRecordDecl>(this))
+    clearLinkageForClass(record);
+
+  if (const ClassTemplateDecl *temp = dyn_cast<ClassTemplateDecl>(this)) {
+    // Clear linkage for the template pattern.
+    CXXRecordDecl *record = temp->getTemplatedDecl();
+    record->HasCachedLinkage = 0;
+    clearLinkageForClass(record);
+
+    // ...do we need to clear linkage for specializations, too?
+  }
+}
+
 Linkage NamedDecl::getLinkage() const {
   if (HasCachedLinkage) {
     assert(Linkage(CachedLinkage) ==
-- 
2.50.1