diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -1062,6 +1062,16 @@
       Mod->getOrInsertFunction("__dfsan_cmp_callback", DFSanCmpCallbackFnTy);
 }
 
+static Constant *getOrInsertGlobal(Module &M, bool &Changed, StringRef Name,
+                                   Type *Ty) {
+  Constant *C = M.getOrInsertGlobal(Name, Ty);
+  if (GlobalVariable *G = dyn_cast<GlobalVariable>(C)) {
+    Changed |= G->getThreadLocalMode() != GlobalVariable::InitialExecTLSModel;
+    G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
+  }
+  return C;
+}
+
 bool DataFlowSanitizer::runImpl(Module &M) {
   init(M);
 
@@ -1073,19 +1083,13 @@
 
   bool Changed = false;
 
-  Type *ArgTLSTy = ArrayType::get(Type::getInt64Ty(*Ctx), kArgTLSSize / 8);
-  ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy);
-  if (GlobalVariable *G = dyn_cast<GlobalVariable>(ArgTLS)) {
-    Changed |= G->getThreadLocalMode() != GlobalVariable::InitialExecTLSModel;
-    G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
-  }
-  Type *RetvalTLSTy =
-      ArrayType::get(Type::getInt64Ty(*Ctx), kRetvalTLSSize / 8);
-  RetvalTLS = Mod->getOrInsertGlobal("__dfsan_retval_tls", RetvalTLSTy);
-  if (GlobalVariable *G = dyn_cast<GlobalVariable>(RetvalTLS)) {
-    Changed |= G->getThreadLocalMode() != GlobalVariable::InitialExecTLSModel;
-    G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
-  }
+  // These globals must be kept in sync with the ones in dfsan.cpp.
+  ArgTLS = getOrInsertGlobal(
+      *Mod, Changed, "__dfsan_arg_tls",
+      ArrayType::get(Type::getInt64Ty(*Ctx), kArgTLSSize / 8));
+  RetvalTLS = getOrInsertGlobal(
+      *Mod, Changed, "__dfsan_retval_tls",
+      ArrayType::get(Type::getInt64Ty(*Ctx), kRetvalTLSSize / 8));
 
   ExternalShadowMask =
       Mod->getOrInsertGlobal(kDFSanExternShadowPtrMask, IntptrTy);