Enable emulated TLS and add test.

interpreter/cling/lib/Interpreter/IncrementalExecutor.cpp

@@ -97,6 +97,9 @@ IncrementalExecutor::IncrementalExecutor(clang::DiagnosticsEngine& diags,
   m_AtExitFuncs.reserve(256);
 
   std::unique_ptr<TargetMachine> TM(CreateHostTargetMachine(CI));
+
+  TM->Options.EmulatedTLS = 1;
+
   m_BackendPasses.reset(new BackendPasses(CI.getCodeGenOpts(),
                                           CI.getTargetOpts(),
                                           CI.getLangOpts(),

interpreter/cling/lib/Utils/CMakeLists.txt

@@ -25,6 +25,7 @@ endif()
 add_cling_library(clingUtils OBJECT
   AST.cpp
   Diagnostics.cpp
+  EmuTLS.cpp
   ParserStateRAII.cpp
   Output.cpp
   Paths.cpp

interpreter/cling/lib/Utils/EmuTLS.cpp

@@ -5,15 +5,24 @@
  * This file is dual licensed under the MIT and the University of Illinois Open
  * Source Licenses. See LICENSE.TXT for details.
  *
+ * Taken from compiler-rt/lib/builtins/emutls.c with additions for Windows
+ *
  * ===----------------------------------------------------------------------===
  */
 
+// When compiling with GCC, use its version of __emutls_get_address
+
+#if defined(__clang__) || defined(_WIN32)
+
+#include "cling/Utils/Casting.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "int_lib.h"
-#include "int_util.h"
+#ifndef COMPILE_TIME_ASSERT
+#define COMPILE_TIME_ASSERT(X) static_assert(X, "Error")
+#endif
 
 typedef struct emutls_address_array {
     uintptr_t size;  /* number of elements in the 'data' array */
@@ -340,10 +349,12 @@ emutls_get_address_array(uintptr_t index) {
     return array;
 }
 
-void* __emutls_get_address(__emutls_control* control) {
+extern "C" void* __emutls_get_address(__emutls_control* control) {
     uintptr_t index = emutls_get_index(control);
     emutls_address_array* array = emutls_get_address_array(index--);
     if (array->data[index] == NULL)
         array->data[index] = emutls_allocate_object(control);
     return array->data[index];
 }
+
+#endif

interpreter/cling/test/CodeGeneration/TLSVars.C

@@ -0,0 +1,54 @@
+//------------------------------------------------------------------------------
+// CLING - the C++ LLVM-based InterpreterG :)
+//
+// This file is dual-licensed: you can choose to license it under the University
+// of Illinois Open Source License or the GNU Lesser General Public License. See
+// LICENSE.TXT for details.
+//------------------------------------------------------------------------------
+
+// RUN: cat %s | %cling -Xclang -verify | FileCheck %s
+
+// Test whether the TLS data is properly handled
+
+#include <string>
+#include <thread>
+#include <mutex>
+#include <stdio.h>
+#include <stdlib.h>
+
+thread_local unsigned int TLSCounter = 1;
+std::mutex WriteMutex;
+
+static void WriteValue(const char* Name, unsigned Val) {
+  std::lock_guard<std::mutex> Lock(WriteMutex);
+  printf("TLSCounter for '%s' : %u\n", Name, Val);
+}
+
+void TLSIncrement(const char* Name) {
+  ++TLSCounter;
+  if (const int Incr = atoi(Name))
+    TLSCounter += Incr;
+  WriteValue(Name, TLSCounter);
+}
+
+static const char* Name[] = {
+  "A",
+  "B",
+  "10",
+  "5",
+  0,
+};
+for (unsigned i = 0; Name[i]; ++i) {
+  std::thread(TLSIncrement, Name[i]).join();
+}
+WriteValue("main", TLSCounter);
+
+
+// CHECK: TLSCounter for 'A' : 2
+// CHECK: TLSCounter for 'B' : 2
+// CHECK: TLSCounter for '10' : 12
+// CHECK: TLSCounter for '5' : 7
+// CHECK: TLSCounter for 'main' : 1
+
+// expected-no-diagnostics
+.q