PR5172: Fix for a bug in pragma redefine_extname implementation:

it doesn't work correctly when a structure is declared before pragma
and then a function with the same name declared after pragma.

Patch by Andrey Bokhanko

Differential Revision: http://reviews.llvm.org/D10187

llvm-svn: 239466

1 files changed, 15 insertions, 9 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 89f4b3a0c1f..047958e2fc2 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -14197,16 +14197,22 @@ 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,