3 files changed, 17 insertions, 1 deletions
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index a3cf69b675..1dab027455 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1214,7 +1214,9 @@ CodeGenModule::GetLLVMLinkageVarDefinition(const VarDecl *D,
     // FIXME: It seems like we can provide more specific linkage here
     // (LinkOnceODR, WeakODR).
     return llvm::GlobalVariable::WeakAnyLinkage;
-  else if (!getLangOptions().CPlusPlus && !CodeGenOpts.NoCommon &&
+  else if (!getLangOptions().CPlusPlus && 
+           ((!CodeGenOpts.NoCommon && !D->getAttr<NoCommonAttr>()) ||
+             D->getAttr<CommonAttr>()) &&
            !D->hasExternalStorage() && !D->getInit() &&
            !D->getAttr<SectionAttr>() && !D->isThreadSpecified()) {
     // Thread local vars aren't considered common linkage.
diff --git a/lib/Sema/AttributeList.cpp b/lib/Sema/AttributeList.cpp
index 409e2488bd..b2ceb53cc5 100644
--- a/lib/Sema/AttributeList.cpp
+++ b/lib/Sema/AttributeList.cpp
@@ -130,5 +130,7 @@ AttributeList::Kind AttributeList::getKind(const IdentifierInfo *Name) {
     .Case("global", AT_global)
     .Case("host", AT_host)
     .Case("shared", AT_shared)
+    .Case("common", AT_common)
+    .Case("nocommon", AT_nocommon)
     .Default(UnknownAttribute);
 }
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index df74e00de0..ee03d1f7f1 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -743,6 +743,16 @@ static void HandleMayAliasAttr(Decl *d, const AttributeList &Attr, Sema &S) {
   d->addAttr(::new (S.Context) MayAliasAttr(Attr.getLoc(), S.Context));
 }
 
+static void HandleNoCommonAttr(Decl *d, const AttributeList &Attr, Sema &S) {
+  assert(Attr.isInvalid() == false);
+  d->addAttr(::new (S.Context) NoCommonAttr(Attr.getLoc(), S.Context));
+}
+
+static void HandleCommonAttr(Decl *d, const AttributeList &Attr, Sema &S) {
+  assert(Attr.isInvalid() == false);
+  d->addAttr(::new (S.Context) CommonAttr(Attr.getLoc(), S.Context));
+}
+
 static void HandleNoReturnAttr(Decl *d, const AttributeList &Attr, Sema &S) {
   /* Diagnostics (if any) was emitted by Sema::ProcessFnAttr(). */
   assert(Attr.isInvalid() == false);
@@ -2474,6 +2484,7 @@ static void ProcessDeclAttribute(Scope *scope, Decl *D,
   case AttributeList::AT_base_check:  HandleBaseCheckAttr   (D, Attr, S); break;
   case AttributeList::AT_carries_dependency:
                                       HandleDependencyAttr  (D, Attr, S); break;
+  case AttributeList::AT_common:      HandleCommonAttr      (D, Attr, S); break;
   case AttributeList::AT_constant:    HandleConstantAttr    (D, Attr, S); break;
   case AttributeList::AT_constructor: HandleConstructorAttr (D, Attr, S); break;
   case AttributeList::AT_deprecated:  HandleDeprecatedAttr  (D, Attr, S); break;
@@ -2492,6 +2503,7 @@ static void ProcessDeclAttribute(Scope *scope, Decl *D,
   case AttributeList::AT_mode:        HandleModeAttr        (D, Attr, S); break;
   case AttributeList::AT_malloc:      HandleMallocAttr      (D, Attr, S); break;
   case AttributeList::AT_may_alias:   HandleMayAliasAttr    (D, Attr, S); break;
+  case AttributeList::AT_nocommon:    HandleNoCommonAttr    (D, Attr, S); break;
   case AttributeList::AT_nonnull:     HandleNonNullAttr     (D, Attr, S); break;
   case AttributeList::AT_ownership_returns:
   case AttributeList::AT_ownership_takes: