From 9901c57806f7e36736ed1616e6ab3eebcc99b78c Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 21 May 2010 00:31:19 +0000
Subject: [PATCH] When instantiating anonymous structs/unions within a
 function, make sure that the anonymous struct/union record declaration gets
 instantiated before the variable declaration, and that it and its fields
 (recursively) get entries in the local instantiation map. Fixes PR7088.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104305 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaTemplateInstantiateDecl.cpp      | 19 ++++++++++++++++++-
 .../instantiate-anonymous-union.cpp           | 18 ++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 592b474dfb..e8cbb66694 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -323,6 +323,13 @@ static bool InstantiateInitializer(Sema &S, Expr *Init,
 }
 
 Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
+  // If this is the variable for an anonymous struct or union,
+  // instantiate the anonymous struct/union type first.
+  if (const RecordType *RecordTy = D->getType()->getAs<RecordType>())
+    if (RecordTy->getDecl()->isAnonymousStructOrUnion())
+      if (!VisitCXXRecordDecl(cast<CXXRecordDecl>(RecordTy->getDecl())))
+        return 0;
+
   // Do substitution on the type of the declaration
   TypeSourceInfo *DI = SemaRef.SubstType(D->getTypeSourceInfo(),
                                          TemplateArgs,
@@ -490,6 +497,11 @@ Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
   if (!Field->getDeclName()) {
     // Keep track of where this decl came from.
     SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
+  } 
+  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {
+    if (Parent->isAnonymousStructOrUnion() &&
+        Parent->getLookupContext()->isFunctionOrMethod())
+      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);
   }
 
   Field->setImplicit(D->isImplicit());
@@ -913,7 +925,12 @@ Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
   if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
     Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
 
-  Record->setAnonymousStructOrUnion(D->isAnonymousStructOrUnion());
+  // Make sure that anonymous structs and unions are recorded.
+  if (D->isAnonymousStructOrUnion()) {
+    Record->setAnonymousStructOrUnion(true);
+    if (Record->getDeclContext()->getLookupContext()->isFunctionOrMethod())
+      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);
+  }
 
   Owner->addDecl(Record);
   return Record;
diff --git a/test/SemaTemplate/instantiate-anonymous-union.cpp b/test/SemaTemplate/instantiate-anonymous-union.cpp
index 7c75885788..255454b2eb 100644
--- a/test/SemaTemplate/instantiate-anonymous-union.cpp
+++ b/test/SemaTemplate/instantiate-anonymous-union.cpp
@@ -29,3 +29,21 @@ template <typename T> struct C {
 };
 
 C<int> c0(0);
+
+namespace PR7088 {
+  template<typename T>
+  void f() { 
+    union { 
+      int a; 
+      union {
+        float real;
+        T d;
+      };
+    }; 
+
+    a = 17;
+    d = 3.14;
+  }
+
+  template void f<double>();
+}
-- 
2.50.1