[-cxx-abi microsoft] Mangle local TagDecls appropriately

Summary:
When selecting a mangling for an anonymous tag type:
- We should first try it's typedef'd name.
- If that doesn't work, we should mangle in the name of the declarator
  that specified it as a declaration specifier.
- If that doesn't work, fall back to a static mangling of
  <unnamed-type>.

This should make our anonymous type mangling compatible.

This partially fixes PR16994; we would need to have an implementation of
scope numbering to get it right (a separate issue).

Reviewers: rnk, rsmith, rjmccall, cdavis5x

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1540

llvm-svn: 190892

6 files changed, 41 insertions, 12 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 0fa1b980f31..dbbf4753dcc 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -3084,7 +3084,7 @@ TagDecl* TagDecl::getCanonicalDecl() {
 }
 
 void TagDecl::setTypedefNameForAnonDecl(TypedefNameDecl *TDD) {
-  TypedefNameDeclOrQualifier = TDD;
+  NamedDeclOrQualifier = TDD;
   if (TypeForDecl)
     assert(TypeForDecl->isLinkageValid());
   assert(isLinkageValid());
@@ -3141,7 +3141,7 @@ void TagDecl::setQualifierInfo(NestedNameSpecifierLoc QualifierLoc) {
   if (QualifierLoc) {
     // Make sure the extended qualifier info is allocated.
     if (!hasExtInfo())
-      TypedefNameDeclOrQualifier = new (getASTContext()) ExtInfo;
+      NamedDeclOrQualifier = new (getASTContext()) ExtInfo;
     // Set qualifier info.
     getExtInfo()->QualifierLoc = QualifierLoc;
   } else {
@@ -3149,7 +3149,7 @@ void TagDecl::setQualifierInfo(NestedNameSpecifierLoc QualifierLoc) {
     if (hasExtInfo()) {
       if (getExtInfo()->NumTemplParamLists == 0) {
         getASTContext().Deallocate(getExtInfo());
-        TypedefNameDeclOrQualifier = (TypedefNameDecl*) 0;
+        NamedDeclOrQualifier = (TypedefNameDecl*) 0;
       }
       else
         getExtInfo()->QualifierLoc = QualifierLoc;
@@ -3164,7 +3164,7 @@ void TagDecl::setTemplateParameterListsInfo(ASTContext &Context,
   // Make sure the extended decl info is allocated.
   if (!hasExtInfo())
     // Allocate external info struct.
-    TypedefNameDeclOrQualifier = new (getASTContext()) ExtInfo;
+    NamedDeclOrQualifier = new (getASTContext()) ExtInfo;
   // Set the template parameter lists info.
   getExtInfo()->setTemplateParameterListsInfo(Context, NumTPLists, TPLists);
 }
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 8506c4c8dde..119bc86be29 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -563,9 +563,15 @@ MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
         break;
       }
 
-      // When VC encounters an anonymous type with no tag and no typedef,
-      // it literally emits '<unnamed-tag>@'.
-      Out << "<unnamed-tag>@";
+      if (TD->hasDeclaratorForAnonDecl())
+        // Anonymous types with no tag or typedef get the name of their
+        // declarator mangled in.
+        Out << "<unnamed-type-" << TD->getDeclaratorForAnonDecl()->getName()
+            << ">@";
+      else
+        // Anonymous types with no tag, no typedef, or declarator get
+        // '<unnamed-tag>@'.
+        Out << "<unnamed-tag>@";
       break;
     }
       
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index a2e05e0094f..beffe414f56 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8814,13 +8814,21 @@ Sema::DeclGroupPtrTy Sema::FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
   if (DS.isTypeSpecOwned())
     Decls.push_back(DS.getRepAsDecl());
 
+  DeclaratorDecl *FirstDeclaratorInGroup = 0;
   for (unsigned i = 0, e = Group.size(); i != e; ++i)
-    if (Decl *D = Group[i])
+    if (Decl *D = Group[i]) {
+      if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D))
+        if (!FirstDeclaratorInGroup)
+          FirstDeclaratorInGroup = DD;
       Decls.push_back(D);
+    }
 
   if (DeclSpec::isDeclRep(DS.getTypeSpecType())) {
-    if (const TagDecl *Tag = dyn_cast_or_null<TagDecl>(DS.getRepAsDecl()))
+    if (TagDecl *Tag = dyn_cast_or_null<TagDecl>(DS.getRepAsDecl())) {
       HandleTagNumbering(*this, Tag);
+      if (!Tag->hasNameForLinkage() && !Tag->hasDeclaratorForAnonDecl())
+        Tag->setDeclaratorForAnonDecl(FirstDeclaratorInGroup);
+    }
   }
 
   return BuildDeclaratorGroup(Decls, DS.containsPlaceholderType());
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index cc9cb6317a1..8cd37258b6a 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3356,6 +3356,19 @@ void Sema::BuildVariableInstantiation(
     NewVar->setReferenced(OldVar->isReferenced());
   }
 
+  // See if the old variable had a type-specifier that defined an anonymous tag.
+  // If it did, mark the new variable as being the declarator for the new
+  // anonymous tag.
+  if (const TagType *OldTagType = OldVar->getType()->getAs<TagType>()) {
+    TagDecl *OldTag = OldTagType->getDecl();
+    if (OldTag->getDeclaratorForAnonDecl() == OldVar) {
+      TagDecl *NewTag = NewVar->getType()->castAs<TagType>()->getDecl();
+      assert(!NewTag->hasNameForLinkage() &&
+             !NewTag->hasDeclaratorForAnonDecl());
+      NewTag->setDeclaratorForAnonDecl(NewVar);
+    }
+  }
+
   InstantiateAttrs(TemplateArgs, OldVar, NewVar, LateAttrs, StartingScope);
 
   if (NewVar->hasAttrs())
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 791f3c9f8ca..a9225fc81be 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -464,9 +464,9 @@ ASTDeclReader::RedeclarableResult ASTDeclReader::VisitTagDecl(TagDecl *TD) {
   if (Record[Idx++]) { // hasExtInfo
     TagDecl::ExtInfo *Info = new (Reader.getContext()) TagDecl::ExtInfo();
     ReadQualifierInfo(*Info, Record, Idx);
-    TD->TypedefNameDeclOrQualifier = Info;
+    TD->NamedDeclOrQualifier = Info;
   } else
-    TD->setTypedefNameForAnonDecl(ReadDeclAs<TypedefNameDecl>(Record, Idx));
+    TD->NamedDeclOrQualifier = ReadDeclAs<NamedDecl>(Record, Idx);
 
   mergeRedeclarable(TD, Redecl);
   return Redecl;
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index dc2ed465758..a9d8a03f717 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -229,8 +229,10 @@ void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
   Record.push_back(D->hasExtInfo());
   if (D->hasExtInfo())
     Writer.AddQualifierInfo(*D->getExtInfo(), Record);
-  else
+  else if (D->getTypedefNameForAnonDecl())
     Writer.AddDeclRef(D->getTypedefNameForAnonDecl(), Record);
+  else if (D->hasDeclaratorForAnonDecl())
+    Writer.AddDeclRef(D->getDeclaratorForAnonDecl(), Record);
 }
 
 void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {