Index: lib/Driver/ToolChains/NetBSD.h
===================================================================
--- lib/Driver/ToolChains/NetBSD.h
+++ lib/Driver/ToolChains/NetBSD.h
@@ -76,6 +76,10 @@
 
   SanitizerMask getSupportedSanitizers() const override;
 
+  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
+                             llvm::opt::ArgStringList &CC1Args,
+                             Action::OffloadKind DeviceOffloadKind) const override;
+
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
Index: lib/Driver/ToolChains/NetBSD.cpp
===================================================================
--- lib/Driver/ToolChains/NetBSD.cpp
+++ lib/Driver/ToolChains/NetBSD.cpp
@@ -457,3 +457,18 @@
   }
   return Res;
 }
+
+void NetBSD::addClangTargetOptions(const ArgList &,
+                                   ArgStringList &CC1Args,
+                                   Action::OffloadKind) const {
+  const SanitizerArgs &SanArgs = getSanitizerArgs();
+  if (SanArgs.needsAsanRt() || SanArgs.needsHwasanRt() ||
+      SanArgs.needsDfsanRt() || SanArgs.needsLsanRt() ||
+      SanArgs.needsMsanRt() || SanArgs.needsTsanRt() ||
+      SanArgs.needsUbsanRt() || SanArgs.needsSafeStackRt() ||
+      SanArgs.needsCfiRt() || SanArgs.needsCfiDiagRt() ||
+      SanArgs.needsStatsRt() || SanArgs.needsEsanRt() ||
+      SanArgs.needsScudoRt()) {
+    CC1Args.push_back("-D_REENTRANT");
+  }
+}