Index: include/llvm/ADT/Triple.h
===================================================================
--- include/llvm/ADT/Triple.h
+++ include/llvm/ADT/Triple.h
@@ -163,6 +163,7 @@
     AMDHSA,     // AMD HSA Runtime
     PS4,
     ELFIAMCU,
+    Contiki,
     TvOS,       // Apple tvOS
     WatchOS,    // Apple watchOS
     Mesa3D,
@@ -469,6 +470,10 @@
     return getOS() == Triple::ELFIAMCU;
   }
 
+  bool isOSContiki() const {
+    return getOS() == Triple::Contiki;
+  }
+
   /// Checks if the environment could be MSVC.
   bool isWindowsMSVCEnvironment() const {
     return getOS() == Triple::Win32 &&
Index: lib/CodeGen/SafeStack.cpp
===================================================================
--- lib/CodeGen/SafeStack.cpp
+++ lib/CodeGen/SafeStack.cpp
@@ -50,17 +50,6 @@
 
 #define DEBUG_TYPE "safestack"
 
-enum UnsafeStackPtrStorageVal { ThreadLocalUSP, SingleThreadUSP };
-
-static cl::opt<UnsafeStackPtrStorageVal> USPStorage("safe-stack-usp-storage",
-    cl::Hidden, cl::init(ThreadLocalUSP),
-    cl::desc("Type of storage for the unsafe stack pointer"),
-    cl::values(clEnumValN(ThreadLocalUSP, "thread-local",
-                          "Thread-local storage"),
-               clEnumValN(SingleThreadUSP, "single-thread",
-                          "Non-thread-local storage"),
-               clEnumValEnd));
-
 namespace llvm {
 
 STATISTIC(NumFunctions, "Total number of functions");
@@ -367,25 +356,19 @@
   auto UnsafeStackPtr =
       dyn_cast_or_null<GlobalVariable>(M.getNamedValue(UnsafeStackPtrVar));
 
-  bool UseTLS = USPStorage == ThreadLocalUSP;
-
   if (!UnsafeStackPtr) {
-    auto TLSModel = UseTLS ?
-        GlobalValue::InitialExecTLSModel :
-        GlobalValue::NotThreadLocal;
     // The global variable is not defined yet, define it ourselves.
     // We use the initial-exec TLS model because we do not support the
     // variable living anywhere other than in the main executable.
     UnsafeStackPtr = new GlobalVariable(
         M, StackPtrTy, false, GlobalValue::ExternalLinkage, nullptr,
-        UnsafeStackPtrVar, nullptr, TLSModel);
+        UnsafeStackPtrVar, nullptr, GlobalValue::InitialExecTLSModel);
   } else {
     // The variable exists, check its type and attributes.
     if (UnsafeStackPtr->getValueType() != StackPtrTy)
       report_fatal_error(Twine(UnsafeStackPtrVar) + " must have void* type");
-    if (UseTLS != UnsafeStackPtr->isThreadLocal())
-      report_fatal_error(Twine(UnsafeStackPtrVar) + " must " +
-                         (UseTLS ? "" : "not ") + "be thread-local");
+    if (!UnsafeStackPtr->isThreadLocal())
+      report_fatal_error(Twine(UnsafeStackPtrVar) + " must be thread-local");
   }
   return UnsafeStackPtr;
 }
Index: lib/Support/Triple.cpp
===================================================================
--- lib/Support/Triple.cpp
+++ lib/Support/Triple.cpp
@@ -186,6 +186,7 @@
   case AMDHSA: return "amdhsa";
   case PS4: return "ps4";
   case ELFIAMCU: return "elfiamcu";
+  case Contiki: return "contiki";
   case TvOS: return "tvos";
   case WatchOS: return "watchos";
   case Mesa3D: return "mesa3d";
@@ -448,6 +449,7 @@
     .StartsWith("amdhsa", Triple::AMDHSA)
     .StartsWith("ps4", Triple::PS4)
     .StartsWith("elfiamcu", Triple::ELFIAMCU)
+    .StartsWith("contiki", Triple::Contiki)
     .StartsWith("tvos", Triple::TvOS)
     .StartsWith("watchos", Triple::WatchOS)
     .StartsWith("mesa3d", Triple::Mesa3D)
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -1937,6 +1937,25 @@
 }
 
 Value *X86TargetLowering::getSafeStackPointerLocation(IRBuilder<> &IRB) const {
+  if (Subtarget.isTargetContiki()) {
+    const char *Name = "__safestack_unsafe_stack_ptr";
+    auto StackPtrTy = Type::getInt8PtrTy(IRB.getContext());
+    Module &M = *IRB.GetInsertBlock()->getParent()->getParent();
+    GlobalVariable *V = dyn_cast_or_null<GlobalVariable>(M.getNamedValue(Name));
+    if (!V) {
+      // The global variable is not defined yet, define it ourselves.
+      V = new GlobalVariable(
+          M, StackPtrTy, false, GlobalValue::ExternalLinkage, nullptr, Name);
+    } else {
+      // The variable exists, check its type and attributes.
+      if (V->getValueType() != StackPtrTy)
+        report_fatal_error(Twine(Name) + " must have void* type");
+      if (V->isThreadLocal())
+        report_fatal_error(Twine(Name) + " must not be thread-local");
+    }
+    return V;
+  }
+
   if (!Subtarget.isTargetAndroid())
     return TargetLowering::getSafeStackPointerLocation(IRB);
 
Index: lib/Target/X86/X86Subtarget.h
===================================================================
--- lib/Target/X86/X86Subtarget.h
+++ lib/Target/X86/X86Subtarget.h
@@ -472,6 +472,7 @@
   bool isTargetNaCl32() const { return isTargetNaCl() && !is64Bit(); }
   bool isTargetNaCl64() const { return isTargetNaCl() && is64Bit(); }
   bool isTargetMCU() const { return TargetTriple.isOSIAMCU(); }
+  bool isTargetContiki() const { return TargetTriple.isOSContiki(); }
 
   bool isTargetWindowsMSVC() const {
     return TargetTriple.isWindowsMSVCEnvironment();
Index: test/Transforms/SafeStack/array.ll
===================================================================
--- test/Transforms/SafeStack/array.ll
+++ test/Transforms/SafeStack/array.ll
@@ -1,7 +1,6 @@
 ; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
-; RUN: opt -safe-stack -safe-stack-usp-storage=single-thread -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck -check-prefix=SINGLE-THREAD %s
+; RUN: opt -safe-stack -S -mtriple=i386-pc-contiki-gnu < %s -o - | FileCheck -check-prefix=SINGLE-THREAD %s
 ; RUN: opt -safe-stack -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
-; RUN: opt -safe-stack -safe-stack-usp-storage=single-thread -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck -check-prefix=SINGLE-THREAD %s
 
 ; array [4 x i8]
 ; Requires protector.