Check for internal weak decls after merging.

This fixes pr14946. The problem was that the linkage computation was done too
early, so things like "extern int a;" would be given external linkage, even if
a previous declaration was static.

llvm-svn: 172667

2 files changed, 13 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 994b2126132..03166546606 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4312,6 +4312,15 @@ bool Sema::inferObjCARCLifetime(ValueDecl *decl) {
   return false;
 }
 
+static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
+  // 'weak' only applies to declarations with external linkage.
+  WeakAttr *WA = ND.getAttr<WeakAttr>();
+  if (WA && ND.getLinkage() != ExternalLinkage) {
+    S.Diag(WA->getLocation(), diag::err_attribute_weak_static);
+    ND.dropAttr<WeakAttr>();
+  }
+}
+
 NamedDecl*
 Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
                               TypeSourceInfo *TInfo, LookupResult &Previous,
@@ -4590,6 +4599,8 @@ Sema::ActOnVariableDeclarator(Scope *S, Declarator &D, DeclContext *DC,
       NewVD->setInvalidDecl();
   }
 
+  checkAttributesAfterMerging(*this, *NewVD);
+
   // If this is a locally-scoped extern C variable, update the map of
   // such variables.
   if (CurContext->isFunctionOrMethod() && NewVD->isExternC() &&
@@ -6056,6 +6067,8 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
     }
   }
 
+  checkAttributesAfterMerging(*this, *NewFD);
+
   AddKnownFunctionAttributes(NewFD);
 
   if (NewFD->hasAttr<OverloadableAttr>() && 
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 85f48ecff35..efeafa697f6 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -2511,12 +2511,6 @@ static void handleWeakAttr(Sema &S, Decl *D, const AttributeList &Attr) {
 
   NamedDecl *nd = cast<NamedDecl>(D);
 
-  // 'weak' only applies to declarations with external linkage.
-  if (hasEffectivelyInternalLinkage(nd)) {
-    S.Diag(Attr.getLoc(), diag::err_attribute_weak_static);
-    return;
-  }
-
   nd->addAttr(::new (S.Context) WeakAttr(Attr.getRange(), S.Context));
 }