r237647 - [modules] Support for merging a parsed definition of a static data member of a class template into an imported but hidden definition.

[Richard Smith]

Author: rsmith
Date: Mon May 18 19:49:29 2015
New Revision: 237647

URL: http://llvm.org/viewvc/llvm-project?rev=237647&view=rev
Log:
[modules] Support for merging a parsed definition of a static data member of a class template into an imported but hidden definition.

Modified:
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/Modules/Inputs/submodules-merge-defs/defs.h

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=237647&r1=237646&r2=237647&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon May 18 19:49:29 2015
@@ -3404,14 +3404,23 @@ void Sema::MergeVarDecl(VarDecl *New, Lo
   }
 
   // C++ doesn't have tentative definitions, so go right ahead and check here.
-  const VarDecl *Def;
+  VarDecl *Def;
   if (getLangOpts().CPlusPlus &&
       New->isThisDeclarationADefinition() == VarDecl::Definition &&
       (Def = Old->getDefinition())) {
-    Diag(New->getLocation(), diag::err_redefinition) << New;
-    Diag(Def->getLocation(), diag::note_previous_definition);
-    New->setInvalidDecl();
-    return;
+    NamedDecl *Hidden = nullptr;
+    if (!hasVisibleDefinition(Def, &Hidden) && 
+        (New->getDescribedVarTemplate() ||
+         New->getNumTemplateParameterLists() ||
+         New->getDeclContext()->isDependentContext())) {
+      // The previous definition is hidden, and multiple definitions are
+      // permitted (in separate TUs). Form another definition of it.
+    } else {
+      Diag(New->getLocation(), diag::err_redefinition) << New;
+      Diag(Def->getLocation(), diag::note_previous_definition);
+      New->setInvalidDecl();
+      return;
+    }
   }
 
   if (haveIncompatibleLanguageLinkages(Old, New)) {
@@ -8883,16 +8892,24 @@ void Sema::AddInitializerToDecl(Decl *Re
       VDecl->setInvalidDecl();
   }
 
-  const VarDecl *Def;
+  VarDecl *Def;
   if ((Def = VDecl->getDefinition()) && Def != VDecl) {
-    Diag(VDecl->getLocation(), diag::err_redefinition)
-      << VDecl->getDeclName();
-    Diag(Def->getLocation(), diag::note_previous_definition);
-    VDecl->setInvalidDecl();
-    return;
+    NamedDecl *Hidden = nullptr;
+    if (!hasVisibleDefinition(Def, &Hidden) && 
+        (VDecl->getDescribedVarTemplate() ||
+         VDecl->getNumTemplateParameterLists() ||
+         VDecl->getDeclContext()->isDependentContext())) {
+      // The previous definition is hidden, and multiple definitions are
+      // permitted (in separate TUs). Form another definition of it.
+    } else {
+      Diag(VDecl->getLocation(), diag::err_redefinition)
+        << VDecl->getDeclName();
+      Diag(Def->getLocation(), diag::note_previous_definition);
+      VDecl->setInvalidDecl();
+      return;
+    }
   }
 
-  const VarDecl *PrevInit = nullptr;
   if (getLangOpts().CPlusPlus) {
     // C++ [class.static.data]p4
     //   If a static data member is of const integral or const
@@ -8906,10 +8923,12 @@ void Sema::AddInitializerToDecl(Decl *Re
     // We already performed a redefinition check above, but for static
     // data members we also need to check whether there was an in-class
     // declaration with an initializer.
-    if (VDecl->isStaticDataMember() && VDecl->getAnyInitializer(PrevInit)) {
+    if (VDecl->isStaticDataMember() && VDecl->getCanonicalDecl()->hasInit()) {
       Diag(Init->getExprLoc(), diag::err_static_data_member_reinitialization)
           << VDecl->getDeclName();
-      Diag(PrevInit->getInit()->getExprLoc(), diag::note_previous_initializer) << 0;
+      Diag(VDecl->getCanonicalDecl()->getInit()->getExprLoc(),
+           diag::note_previous_initializer)
+          << 0;
       return;
     }  
 

Modified: cfe/trunk/test/Modules/Inputs/submodules-merge-defs/defs.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/submodules-merge-defs/defs.h?rev=237647&r1=237646&r2=237647&view=diff
==============================================================================
--- cfe/trunk/test/Modules/Inputs/submodules-merge-defs/defs.h (original)
+++ cfe/trunk/test/Modules/Inputs/submodules-merge-defs/defs.h Mon May 18 19:49:29 2015
@@ -26,9 +26,11 @@ template<typename T> int E(T t) { return
 template<typename T> struct F {
   int f();
   template<typename U> int g();
+  static int n;
 };
 template<typename T> int F<T>::f() { return 0; }
 template<typename T> template<typename U> int F<T>::g() { return 0; }
+template<typename T> int F<T>::n = 0;
 template<> template<typename U> int F<char>::g() { return 0; }
 template<> struct F<void> { int h(); };
 inline int F<void>::h() { return 0; }