From beba3e80378f38f3d1e1ef030dacdd438373d3d5 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Mon, 20 May 2013 21:53:29 +0000
Subject: [PATCH] Warn on and drop dllimport attrs from variable definitions

AsmPrinter::EmitLinkage() does not handle dllimport linkage.  The LLVM
verifier should also be fixed to reject this.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182320 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/DiagnosticSemaKinds.td | 4 ++--
 lib/Sema/SemaDeclAttr.cpp                  | 5 ++---
 lib/Sema/TargetAttributesSema.cpp          | 9 +++++++++
 test/Sema/dllimport-dllexport.c            | 5 +++++
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index f1a179c259..f52d1f3162 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1957,8 +1957,8 @@ def err_attribute_weak_static : Error<
   "weak declaration cannot have internal linkage">;
 def err_attribute_selectany_non_extern_data : Error<
   "'selectany' can only be applied to data items with external linkage">;
-def warn_attribute_weak_import_invalid_on_definition : Warning<
-  "'weak_import' attribute cannot be specified on a definition">,
+def warn_attribute_invalid_on_definition : Warning<
+  "'%0' attribute cannot be specified on a definition">,
   InGroup<IgnoredAttributes>;
 def err_attribute_weakref_not_static : Error<
   "weakref declaration must have internal linkage">;
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 627bc3d364..be4bd0e3b7 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -2725,9 +2725,8 @@ static void handleWeakImportAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   bool isDef = false;
   if (!D->canBeWeakImported(isDef)) {
     if (isDef)
-      S.Diag(Attr.getLoc(),
-             diag::warn_attribute_weak_import_invalid_on_definition)
-        << "weak_import" << 2 /*variable and function*/;
+      S.Diag(Attr.getLoc(), diag::warn_attribute_invalid_on_definition)
+        << "weak_import";
     else if (isa<ObjCPropertyDecl>(D) || isa<ObjCMethodDecl>(D) ||
              (S.Context.getTargetInfo().getTriple().isOSDarwin() &&
               (isa<ObjCInterfaceDecl>(D) || isa<EnumDecl>(D)))) {
diff --git a/lib/Sema/TargetAttributesSema.cpp b/lib/Sema/TargetAttributesSema.cpp
index 2f7701227d..526399a278 100644
--- a/lib/Sema/TargetAttributesSema.cpp
+++ b/lib/Sema/TargetAttributesSema.cpp
@@ -161,6 +161,15 @@ DLLImportAttr *Sema::mergeDLLImportAttr(Decl *D, SourceRange Range,
   if (D->hasAttr<DLLImportAttr>())
     return NULL;
 
+  if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
+    if (VD->hasDefinition()) {
+      // dllimport cannot be applied to definitions.
+      Diag(D->getLocation(), diag::warn_attribute_invalid_on_definition)
+        << "dllimport";
+      return NULL;
+    }
+  }
+
   return ::new (Context) DLLImportAttr(Range, Context,
                                        AttrSpellingListIndex);
 }
diff --git a/test/Sema/dllimport-dllexport.c b/test/Sema/dllimport-dllexport.c
index 00c9df594b..80810d696e 100644
--- a/test/Sema/dllimport-dllexport.c
+++ b/test/Sema/dllimport-dllexport.c
@@ -41,3 +41,8 @@ void __attribute__((dllexport)) foo13();
 
 extern int foo14 __attribute__((dllexport));
 extern int foo14 __attribute__((dllimport));  // expected-warning{{dllimport attribute ignored}}
+
+__declspec(dllimport) int foo15 = 54; // expected-warning{{'dllimport' attribute cannot be specified on a definition}}
+
+extern __declspec(dllimport) int foo17;
+int foo17 = 54; // expected-warning{{'dllimport' attribute cannot be specified on a definition}}
-- 
2.40.0