During name lookup, use redecl_iterator to walk over the redeclaration

chain to determine whether any declaration of the given entity is
visible, eliminating the redundant (and less efficient)
getPreviousDeclaration() implementation.

This tweak uncovered an omission in the handling of
RedeclarableTemplateDecl, where we weren't making sure to search for
additional redeclarations of a template in other module files. Things
would be cleaner if RedeclarableTemplateDecl actually used Redeclarable.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147687 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaLookup.cpp

@@ -1053,26 +1053,6 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
   return !R.empty();
 }
 
-/// \brief Retrieve the previous declaration of D.
-static NamedDecl *getPreviousDeclaration(NamedDecl *D) {
-  if (TagDecl *TD = dyn_cast<TagDecl>(D))
-    return TD->getPreviousDeclaration();
-  if (VarDecl *VD = dyn_cast<VarDecl>(D))
-    return VD->getPreviousDeclaration();
-  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
-    return FD->getPreviousDeclaration();
-  if (RedeclarableTemplateDecl *RTD = dyn_cast<RedeclarableTemplateDecl>(D))
-    return RTD->getPreviousDeclaration();
-  if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D))
-    return TD->getPreviousDeclaration();
-  if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D))
-    return ID->getPreviousDeclaration();
-  if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D))
-    return PD->getPreviousDeclaration();
-  
-  return 0;
-}
-
 /// \brief Retrieve the visible declaration corresponding to D, if any.
 ///
 /// This routine determines whether the declaration D is visible in the current
@@ -1085,9 +1065,12 @@ static NamedDecl *getVisibleDecl(NamedDecl *D) {
   if (LookupResult::isVisible(D))
     return D;
   
-  while ((D = getPreviousDeclaration(D))) {
-    if (LookupResult::isVisible(D))
-      return D;
+  for (Decl::redecl_iterator RD = D->redecls_begin(), RDEnd = D->redecls_end();
+       RD != RDEnd; ++RD) {
+    if (NamedDecl *ND = dyn_cast<NamedDecl>(*RD)) {
+      if (LookupResult::isVisible(ND))
+        return ND;
+    }
   }
   
   return 0;

lib/Serialization/ASTReaderDecl.cpp

@@ -255,7 +255,7 @@ namespace clang {
     void VisitParmVarDecl(ParmVarDecl *PD);
     void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
     void VisitTemplateDecl(TemplateDecl *D);
-    void VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
+    RedeclarableResult VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D);
     void VisitClassTemplateDecl(ClassTemplateDecl *D);
     void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
     void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
@@ -1219,7 +1219,8 @@ void ASTDeclReader::VisitTemplateDecl(TemplateDecl *D) {
   D->init(TemplatedDecl, TemplateParams);
 }
 
-void ASTDeclReader::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
+ASTDeclReader::RedeclarableResult 
+ASTDeclReader::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
   // Initialize CommonOrPrev before VisitTemplateDecl so that getCommonPtr()
   // can be used while this is still initializing.
   enum RedeclKind { FirstDeclaration, FirstInFile, PointsToPrevious };
@@ -1278,6 +1279,8 @@ void ASTDeclReader::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
   
   VisitTemplateDecl(D);
   D->IdentifierNamespace = Record[Idx++];
+  
+  return RedeclarableResult(Reader, FirstDeclID);
 }
 
 void ASTDeclReader::VisitClassTemplateDecl(ClassTemplateDecl *D) {