Re-revert r86040, which was un-reverted in r186199.

This breaks the build of basic patterns with repeated friend
declarations. See the added test case in SemaCXX/friend.cpp or the test
case reported to the original commit log.

Original commit log:
  If we friend a declaration twice, that should not make it visible to
  name lookup in the surrounding context. Slightly rework how we handle
  friend declarations to inherit the visibility of the prior
  declaration, rather than setting a friend declaration to be visible
  whenever there was a prior declaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186331 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index bc588ac4542b26fe06f97becb14943f287c608bb..6dbdc1307be66fe7753aa9cd7281b82592954911 100644 (file)
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -3415,12 +3415,6 @@ void Redeclarable<decl_type>::setPreviousDeclaration(decl_type *PrevDecl) {
   First->RedeclLink = LatestDeclLink(static_cast<decl_type*>(this));
   assert(!isa<NamedDecl>(static_cast<decl_type*>(this)) ||
          cast<NamedDecl>(static_cast<decl_type*>(this))->isLinkageValid());
-
-  // If the declaration was previously visible, a redeclaration of it remains
-  // visible even if it wouldn't be visible by itself.
-  static_cast<decl_type*>(this)->IdentifierNamespace |=
-    First->getIdentifierNamespace() &
-    (Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Type);
 }
 
 // Inline function definitions.

diff --git a/include/clang/AST/DeclBase.h b/include/clang/AST/DeclBase.h
index c19d3cf841834a9b751b42e7af7127d684f36b9e..b46fdf319fc78de7fed0b2edaa927b17c566453e 100644 (file)
--- a/include/clang/AST/DeclBase.h
+++ b/include/clang/AST/DeclBase.h
@@ -295,8 +295,6 @@ protected:
   friend class ASTReader;
   friend class LinkageComputer;
 
-  template<typename decl_type> friend class Redeclarable;
-
 private:
   void CheckAccessDeclContext() const;
 
@@ -826,7 +824,7 @@ public:
   /// class, but in the semantic context of the actual entity.  This property
   /// applies only to a specific decl object;  other redeclarations of the
   /// same entity may not (and probably don't) share this property.
-  void setObjectOfFriendDecl(bool PerformFriendInjection = false) {
+  void setObjectOfFriendDecl(bool PreviouslyDeclared) {
     unsigned OldNS = IdentifierNamespace;
     assert((OldNS & (IDNS_Tag | IDNS_Ordinary |
                      IDNS_TagFriend | IDNS_OrdinaryFriend)) &&
@@ -835,20 +833,15 @@ public:
                        IDNS_TagFriend | IDNS_OrdinaryFriend)) &&
            "namespace includes other than ordinary or tag");
 
-    Decl *Prev = getPreviousDecl();
     IdentifierNamespace = 0;
     if (OldNS & (IDNS_Tag | IDNS_TagFriend)) {
       IdentifierNamespace |= IDNS_TagFriend;
-      if (PerformFriendInjection || 
-          (Prev && Prev->getIdentifierNamespace() & IDNS_Tag))
-        IdentifierNamespace |= IDNS_Tag | IDNS_Type;
+      if (PreviouslyDeclared) IdentifierNamespace |= IDNS_Tag | IDNS_Type;
     }
 
     if (OldNS & (IDNS_Ordinary | IDNS_OrdinaryFriend)) {
       IdentifierNamespace |= IDNS_OrdinaryFriend;
-      if (PerformFriendInjection ||
-          (Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary))
-        IdentifierNamespace |= IDNS_Ordinary;
+      if (PreviouslyDeclared) IdentifierNamespace |= IDNS_Ordinary;
     }
   }
 

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index fd4ddcf55e657ec10d822f9a9b2144f6575ee429..5e535da19a1464e01a4f68ee42bd4bad90a62983 100644 (file)
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -6328,11 +6328,12 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
     }
 
     if (isFriend) {
+      // For now, claim that the objects have no previous declaration.
       if (FunctionTemplate) {
-        FunctionTemplate->setObjectOfFriendDecl();
+        FunctionTemplate->setObjectOfFriendDecl(false);
         FunctionTemplate->setAccess(AS_public);
       }
-      NewFD->setObjectOfFriendDecl();
+      NewFD->setObjectOfFriendDecl(false);
       NewFD->setAccess(AS_public);
     }
 
@@ -6651,6 +6652,8 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
 
       NewFD->setAccess(Access);
       if (FunctionTemplate) FunctionTemplate->setAccess(Access);
+
+      PrincipalDecl->setObjectOfFriendDecl(true);
     }
 
     if (NewFD->isOverloadedOperator() && !DC->isRecord() &&
@@ -10381,8 +10384,9 @@ CreateNewDecl:
   // declaration so we always pass true to setObjectOfFriendDecl to make
   // the tag name visible.
   if (TUK == TUK_Friend)
-    New->setObjectOfFriendDecl(!FriendSawTagOutsideEnclosingNamespace &&
-                               getLangOpts().MicrosoftExt);
+    New->setObjectOfFriendDecl(/* PreviouslyDeclared = */ !Previous.empty() ||
+                               (!FriendSawTagOutsideEnclosingNamespace &&
+                                getLangOpts().MicrosoftExt));
 
   // Set the access specifier.
   if (!Invalid && SearchDC->isRecord())

diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index 3769c14c0b2f743ceae1cd61ecc17e488c694c6b..8dedee8926288ea8ce8f487ea6280f4b0f82982d 100644 (file)
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -2757,15 +2757,8 @@ void Sema::ArgumentDependentLookup(DeclarationName Name, bool Operator,
       // If the only declaration here is an ordinary friend, consider
       // it only if it was declared in an associated classes.
       if (D->getIdentifierNamespace() == Decl::IDNS_OrdinaryFriend) {
-        bool DeclaredInAssociatedClass = false;
-        for (Decl *DI = D; DI; DI = DI->getPreviousDecl()) {
-          DeclContext *LexDC = DI->getLexicalDeclContext();
-          if (AssociatedClasses.count(cast<CXXRecordDecl>(LexDC))) {
-            DeclaredInAssociatedClass = true;
-            break;
-          }
-        }
-        if (!DeclaredInAssociatedClass)
+        DeclContext *LexDC = D->getLexicalDeclContext();
+        if (!AssociatedClasses.count(cast<CXXRecordDecl>(LexDC)))
           continue;
       }
 

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 6f1ab19f10e061d2a61cf36973cad960b2c2d4a2..e6006b6bf973d87ba1214d739b154fede2bdfcf3 100644 (file)
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -1120,7 +1120,8 @@ Sema::CheckClassTemplate(Scope *S, unsigned TagSpec, TagUseKind TUK,
       NewClass->setAccess(PrevClassTemplate->getAccess());
     }
 
-    NewTemplate->setObjectOfFriendDecl();
+    NewTemplate->setObjectOfFriendDecl(/* PreviouslyDeclared = */
+                                       PrevClassTemplate != NULL);
 
     // Friend templates are visible in fairly strange ways.
     if (!CurContext->isDependentContext()) {

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 420ccb167fbcfabc1b6580cb470e1d4435700aaf..37591a373434e4880b7bb199bd6527d4b21d1d1f 100644 (file)
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -960,7 +960,7 @@ Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
     else
       Inst->setAccess(D->getAccess());
 
-    Inst->setObjectOfFriendDecl();
+    Inst->setObjectOfFriendDecl(PrevClassTemplate != 0);
     // TODO: do we want to track the instantiation progeny of this
     // friend target decl?
   } else {
@@ -1110,8 +1110,8 @@ Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
 
   // If the original function was part of a friend declaration,
   // inherit its namespace state.
-  if (D->getFriendObjectKind())
-    Record->setObjectOfFriendDecl();
+  if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
+    Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
 
   // Make sure that anonymous structs and unions are recorded.
   if (D->isAnonymousStructOrUnion()) {
@@ -1315,7 +1315,7 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
     assert(isFriend && "non-friend has dependent specialization info?");
 
     // This needs to be set now for future sanity.
-    Function->setObjectOfFriendDecl();
+    Function->setObjectOfFriendDecl(/*HasPrevious*/ true);
 
     // Instantiate the explicit template arguments.
     TemplateArgumentListInfo ExplicitArgs(Info->getLAngleLoc(),
@@ -1365,7 +1365,13 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
   // If the original function was part of a friend declaration,
   // inherit its namespace state and add it to the owner.
   if (isFriend) {
-    PrincipalDecl->setObjectOfFriendDecl();
+    NamedDecl *PrevDecl;
+    if (TemplateParams)
+      PrevDecl = FunctionTemplate->getPreviousDecl();
+    else
+      PrevDecl = Function->getPreviousDecl();
+
+    PrincipalDecl->setObjectOfFriendDecl(PrevDecl != 0);
     DC->makeDeclVisibleInContext(PrincipalDecl);
 
     bool queuedInstantiation = false;
@@ -1633,7 +1639,7 @@ TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
                                                     TemplateParams, Method);
     if (isFriend) {
       FunctionTemplate->setLexicalDeclContext(Owner);
-      FunctionTemplate->setObjectOfFriendDecl();
+      FunctionTemplate->setObjectOfFriendDecl(true);
     } else if (D->isOutOfLine())
       FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());
     Method->setDescribedFunctionTemplate(FunctionTemplate);
@@ -1660,7 +1666,7 @@ TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D,
                                             TempParamLists.data());
 
     Method->setLexicalDeclContext(Owner);
-    Method->setObjectOfFriendDecl();
+    Method->setObjectOfFriendDecl(true);
   } else if (D->isOutOfLine())
     Method->setLexicalDeclContext(D->getLexicalDeclContext());
 

diff --git a/test/CXX/temp/temp.decls/temp.friend/p4.cpp b/test/CXX/temp/temp.decls/temp.friend/p4.cpp
index 8571a141201bdb2d4b13c1ddc33db4033f4d8bc4..e036cef32b283e5a712ea3d374ecf9148077f2a2 100644 (file)
--- a/test/CXX/temp/temp.decls/temp.friend/p4.cpp
+++ b/test/CXX/temp/temp.decls/temp.friend/p4.cpp
@@ -26,20 +26,3 @@ void g() {
   X2<float> xf; 
   f(xf);
 }
-
-template<typename T>
-struct X3 {
-  operator int();
-
-  friend void h(int x);
-};
-
-int array2[sizeof(X3<int>)]; 
-int array3[sizeof(X3<float>)];
-
-void i() {
-  X3<int> xi;
-  h(xi);
-  X3<float> xf; 
-  h(xf);
-}

diff --git a/test/SemaCXX/friend.cpp b/test/SemaCXX/friend.cpp
index 4d7ead2a5733135f73404ccca94f5fc56dc72753..86fb2a78bc19c5577899417011a3462c2bcf3252 100644 (file)
--- a/test/SemaCXX/friend.cpp
+++ b/test/SemaCXX/friend.cpp
@@ -166,24 +166,13 @@ namespace test9 {
 
 namespace test10 {
   struct A {
-    friend void f10();
+    friend void f();
   };
+  extern void f();
   struct B {
-    friend void f10();
+    friend void f();
   };
   void g() {
-    f10(); // expected-error {{undeclared identifier}}
+    ::test10::f();
   }
 }
-
-namespace PR16597 {
-  struct A {
-    friend void f_16597();
-  };
-  struct B {
-    friend void f_16597();
-  };
-  struct C {
-  };
-  void g(C a) { f_16597(a); } // expected-error {{undeclared identifier}}
-}