1 files changed, 72 insertions, 19 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 89f4b3a0c1fb..aa006b31fc89 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1007,7 +1007,7 @@ Corrected:
 
   // Check for a tag type hidden by a non-type decl in a few cases where it
   // seems likely a type is wanted instead of the non-type that was found.
-  bool NextIsOp = NextToken.is(tok::amp) || NextToken.is(tok::star);
+  bool NextIsOp = NextToken.isOneOf(tok::amp, tok::star);
   if ((NextToken.is(tok::identifier) ||
        (NextIsOp &&
         FirstDecl->getUnderlyingDecl()->isFunctionOrFunctionTemplate())) &&
@@ -1081,6 +1081,22 @@ void Sema::PopDeclContext() {
   assert(CurContext && "Popped translation unit!");
 }
 
+Sema::SkippedDefinitionContext Sema::ActOnTagStartSkippedDefinition(Scope *S,
+                                                                    Decl *D) {
+  // Unlike PushDeclContext, the context to which we return is not necessarily
+  // the containing DC of TD, because the new context will be some pre-existing
+  // TagDecl definition instead of a fresh one.
+  auto Result = static_cast<SkippedDefinitionContext>(CurContext);
+  CurContext = cast<TagDecl>(D)->getDefinition();
+  assert(CurContext && "skipping definition of undefined tag");
+  S->setEntity(CurContext);
+  return Result;
+}
+
+void Sema::ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context) {
+  CurContext = static_cast<decltype(CurContext)>(Context);
+}
+
 /// EnterDeclaratorContext - Used when we must lookup names in the context
 /// of a declarator's nested name specifier.
 ///
@@ -1788,7 +1804,7 @@ static void filterNonConflictingPreviousDecls(Sema &S,
                                               NamedDecl *decl,
                                               LookupResult &previous){
   // This is only interesting when modules are enabled.
-  if (!S.getLangOpts().Modules)
+  if (!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility)
     return;
 
   // Empty sets are uninteresting.
@@ -1818,7 +1834,7 @@ static void filterNonConflictingPreviousTypedefDecls(Sema &S,
                                                      TypedefNameDecl *Decl,
                                                      LookupResult &Previous) {
   // This is only interesting when modules are enabled.
-  if (!S.getLangOpts().Modules)
+  if (!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility)
     return;
 
   // Empty sets are uninteresting.
@@ -2449,6 +2465,32 @@ static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
   if (!foundAny) newDecl->dropAttrs();
 }
 
+static void mergeParamDeclTypes(ParmVarDecl *NewParam,
+                                const ParmVarDecl *OldParam,
+                                Sema &S) {
+  if (auto Oldnullability = OldParam->getType()->getNullability(S.Context)) {
+    if (auto Newnullability = NewParam->getType()->getNullability(S.Context)) {
+      if (*Oldnullability != *Newnullability) {
+        unsigned unsNewnullability = static_cast<unsigned>(*Newnullability);
+        unsigned unsOldnullability = static_cast<unsigned>(*Oldnullability);
+        S.Diag(NewParam->getLocation(), diag::warn_mismatched_nullability_attr)
+          << unsNewnullability
+          << ((NewParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability) != 0)
+          << unsOldnullability
+          << ((OldParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability) != 0);
+        S.Diag(OldParam->getLocation(), diag::note_previous_declaration);
+      }
+    }
+    else {
+      QualType NewT = NewParam->getType();
+      NewT = S.Context.getAttributedType(
+                         AttributedType::getNullabilityAttrKind(*Oldnullability),
+                         NewT, NewT);
+      NewParam->setType(NewT);
+    }
+  }
+}
+
 namespace {
 
 /// Used in MergeFunctionDecl to keep track of function parameters in
@@ -3085,9 +3127,12 @@ bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
   // Merge attributes from the parameters.  These can mismatch with K&R
   // declarations.
   if (New->getNumParams() == Old->getNumParams())
-    for (unsigned i = 0, e = New->getNumParams(); i != e; ++i)
-      mergeParamDeclAttributes(New->getParamDecl(i), Old->getParamDecl(i),
-                               *this);
+      for (unsigned i = 0, e = New->getNumParams(); i != e; ++i) {
+        ParmVarDecl *NewParam = New->getParamDecl(i);
+        ParmVarDecl *OldParam = Old->getParamDecl(i);
+        mergeParamDeclAttributes(NewParam, OldParam, *this);
+        mergeParamDeclTypes(NewParam, OldParam, *this);
+      }
 
   if (getLangOpts().CPlusPlus)
     return MergeCXXFunctionDecl(New, Old, S);
@@ -4663,12 +4708,14 @@ NamedDecl *Sema::HandleDeclarator(Scope *S, Declarator &D,
         RequireCompleteDeclContext(D.getCXXScopeSpec(), DC))
       return nullptr;
 
+    // If a class is incomplete, do not parse entities inside it.
     if (isa<CXXRecordDecl>(DC) && !cast<CXXRecordDecl>(DC)->hasDefinition()) {
       Diag(D.getIdentifierLoc(),
            diag::err_member_def_undefined_record)
         << Name << DC << D.getCXXScopeSpec().getRange();
-      D.setInvalidType();
-    } else if (!D.getDeclSpec().isFriendSpecified()) {
+      return nullptr;
+    }
+    if (!D.getDeclSpec().isFriendSpecified()) {
       if (diagnoseQualifiedDeclaration(D.getCXXScopeSpec(), DC,
                                       Name, D.getIdentifierLoc())) {
         if (DC->isRecord())
@@ -13486,7 +13533,8 @@ EnumConstantDecl *Sema::CheckEnumConstant(EnumDecl *Enum,
 
 Sema::SkipBodyInfo Sema::shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                                 SourceLocation IILoc) {
-  if (!getLangOpts().Modules || !getLangOpts().CPlusPlus)
+  if (!(getLangOpts().Modules || getLangOpts().ModulesLocalVisibility) ||
+      !getLangOpts().CPlusPlus)
     return SkipBodyInfo();
 
   // We have an anonymous enum definition. Look up the first enumerator to
@@ -13500,7 +13548,6 @@ Sema::SkipBodyInfo Sema::shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
       !hasVisibleDefinition(cast<NamedDecl>(PrevECD->getDeclContext()),
                             &Hidden)) {
     SkipBodyInfo Skip;
-    Skip.ShouldSkip = true;
     Skip.Previous = Hidden;
     return Skip;
   }
@@ -14197,16 +14244,22 @@ void Sema::ActOnPragmaRedefineExtname(IdentifierInfo* Name,
                                       SourceLocation PragmaLoc,
                                       SourceLocation NameLoc,
                                       SourceLocation AliasNameLoc) {
-  Decl *PrevDecl = LookupSingleName(TUScope, Name, NameLoc,
-                                    LookupOrdinaryName);
-  AsmLabelAttr *Attr = ::new (Context) AsmLabelAttr(AliasNameLoc, Context,
-                                                    AliasName->getName(), 0);
-
-  if (PrevDecl) 
+  NamedDecl *PrevDecl = LookupSingleName(TUScope, Name, NameLoc,
+                                         LookupOrdinaryName);
+  AsmLabelAttr *Attr =
+      AsmLabelAttr::CreateImplicit(Context, AliasName->getName(), AliasNameLoc);
+
+  // If a declaration that:
+  // 1) declares a function or a variable
+  // 2) has external linkage
+  // already exists, add a label attribute to it.
+  if (PrevDecl &&
+      (isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl)) &&
+      PrevDecl->hasExternalFormalLinkage())
     PrevDecl->addAttr(Attr);
-  else 
-    (void)ExtnameUndeclaredIdentifiers.insert(
-      std::pair<IdentifierInfo*,AsmLabelAttr*>(Name, Attr));
+  // Otherwise, add a label atttibute to ExtnameUndeclaredIdentifiers.
+  else
+    (void)ExtnameUndeclaredIdentifiers.insert(std::make_pair(Name, Attr));
 }
 
 void Sema::ActOnPragmaWeakID(IdentifierInfo* Name,