Extend the IL for selecting TLS models (PR9788)

This allows the user/front-end to specify a model that is better
than what LLVM would choose by default. For example, a variable
might be declared as

  @x = thread_local(initialexec) global i32 42

if it will not be used in a shared library that is dlopen'ed.

If the specified model isn't supported by the target, or if LLVM can
make a better choice, a different model may be used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159077 91177308-0d34-0410-b5e6-96231b3b80d8

17 files changed, 221 insertions, 36 deletions

diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index dabcbaa9e8..670c1bbe98 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -474,6 +474,9 @@ lltok::Kind LLLexer::LexIdentifier() {
   KEYWORD(extern_weak);
   KEYWORD(external);
   KEYWORD(thread_local);
+  KEYWORD(localdynamic);
+  KEYWORD(initialexec);
+  KEYWORD(localexec);
   KEYWORD(zeroinitializer);
   KEYWORD(undef);
   KEYWORD(null);
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index fe415615d8..095b7c5f67 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -645,12 +645,13 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
                            unsigned Linkage, bool HasLinkage,
                            unsigned Visibility) {
   unsigned AddrSpace;
-  bool ThreadLocal, IsConstant, UnnamedAddr;
+  bool IsConstant, UnnamedAddr;
+  GlobalVariable::ThreadLocalMode TLM;
   LocTy UnnamedAddrLoc;
   LocTy TyLoc;
 
   Type *Ty = 0;
-  if (ParseOptionalToken(lltok::kw_thread_local, ThreadLocal) ||
+  if (ParseOptionalThreadLocal(TLM) ||
       ParseOptionalAddrSpace(AddrSpace) ||
       ParseOptionalToken(lltok::kw_unnamed_addr, UnnamedAddr,
                          &UnnamedAddrLoc) ||
@@ -691,7 +692,8 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
 
   if (GV == 0) {
     GV = new GlobalVariable(*M, Ty, false, GlobalValue::ExternalLinkage, 0,
-                            Name, 0, false, AddrSpace);
+                            Name, 0, GlobalVariable::NotThreadLocal,
+                            AddrSpace);
   } else {
     if (GV->getType()->getElementType() != Ty)
       return Error(TyLoc,
@@ -710,7 +712,7 @@ bool LLParser::ParseGlobal(const std::string &Name, LocTy NameLoc,
   GV->setConstant(IsConstant);
   GV->setLinkage((GlobalValue::LinkageTypes)Linkage);
   GV->setVisibility((GlobalValue::VisibilityTypes)Visibility);
-  GV->setThreadLocal(ThreadLocal);
+  GV->setThreadLocalMode(TLM);
   GV->setUnnamedAddr(UnnamedAddr);
 
   // Parse attributes on the global.
@@ -858,6 +860,46 @@ bool LLParser::ParseUInt32(unsigned &Val) {
   return false;
 }
 
+/// ParseTLSModel
+///   := 'localdynamic'
+///   := 'initialexec'
+///   := 'localexec'
+bool LLParser::ParseTLSModel(GlobalVariable::ThreadLocalMode &TLM) {
+  switch (Lex.getKind()) {
+    default:
+      return TokError("expected localdynamic, initialexec or localexec");
+    case lltok::kw_localdynamic:
+      TLM = GlobalVariable::LocalDynamicTLSModel;
+      break;
+    case lltok::kw_initialexec:
+      TLM = GlobalVariable::InitialExecTLSModel;
+      break;
+    case lltok::kw_localexec:
+      TLM = GlobalVariable::LocalExecTLSModel;
+      break;
+  }
+
+  Lex.Lex();
+  return false;
+}
+
+/// ParseOptionalThreadLocal
+///   := /*empty*/
+///   := 'thread_local'
+///   := 'thread_local' '(' tlsmodel ')'
+bool LLParser::ParseOptionalThreadLocal(GlobalVariable::ThreadLocalMode &TLM) {
+  TLM = GlobalVariable::NotThreadLocal;
+  if (!EatIfPresent(lltok::kw_thread_local))
+    return false;
+
+  TLM = GlobalVariable::GeneralDynamicTLSModel;
+  if (Lex.getKind() == lltok::lparen) {
+    Lex.Lex();
+    return ParseTLSModel(TLM) ||
+      ParseToken(lltok::rparen, "expected ')' after thread local model");
+  }
+  return false;
+}
 
 /// ParseOptionalAddrSpace
 ///   := /*empty*/
diff --git a/lib/AsmParser/LLParser.h b/lib/AsmParser/LLParser.h
index dda8808381..257c726229 100644
--- a/lib/AsmParser/LLParser.h
+++ b/lib/AsmParser/LLParser.h
@@ -171,6 +171,9 @@ namespace llvm {
       Loc = Lex.getLoc();
       return ParseUInt32(Val);
     }
+
+    bool ParseTLSModel(GlobalVariable::ThreadLocalMode &TLM);
+    bool ParseOptionalThreadLocal(GlobalVariable::ThreadLocalMode &TLM);
     bool ParseOptionalAddrSpace(unsigned &AddrSpace);
     bool ParseOptionalAttrs(Attributes &Attrs, unsigned AttrKind);
     bool ParseOptionalLinkage(unsigned &Linkage, bool &HasLinkage);
diff --git a/lib/AsmParser/LLToken.h b/lib/AsmParser/LLToken.h
index adf5d4f4d0..0461e7b63a 100644
--- a/lib/AsmParser/LLToken.h
+++ b/lib/AsmParser/LLToken.h
@@ -44,13 +44,14 @@ namespace lltok {
     kw_unnamed_addr,
     kw_extern_weak,
     kw_external, kw_thread_local,
+    kw_localdynamic, kw_initialexec, kw_localexec,
     kw_zeroinitializer,
     kw_undef, kw_null,
     kw_to,
     kw_tail,
     kw_target,
     kw_triple,
-    kw_unwind, 
+    kw_unwind,
     kw_deplibs,
     kw_datalayout,
     kw_volatile,
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 83756daa7a..4a20b1c9d6 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -102,6 +102,17 @@ static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
   }
 }
 
+static GlobalVariable::ThreadLocalMode GetDecodedThreadLocalMode(unsigned Val) {
+  switch (Val) {
+    case 0: return GlobalVariable::NotThreadLocal;
+    default: // Map unknown non-zero value to general dynamic.
+    case 1: return GlobalVariable::GeneralDynamicTLSModel;
+    case 2: return GlobalVariable::LocalDynamicTLSModel;
+    case 3: return GlobalVariable::InitialExecTLSModel;
+    case 4: return GlobalVariable::LocalExecTLSModel;
+  }
+}
+
 static int GetDecodedCastOpcode(unsigned Val) {
   switch (Val) {
   default: return -1;
@@ -1544,9 +1555,10 @@ bool BitcodeReader::ParseModule(bool Resume) {
       GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
       if (Record.size() > 6)
         Visibility = GetDecodedVisibility(Record[6]);
-      bool isThreadLocal = false;
+
+      GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
       if (Record.size() > 7)
-        isThreadLocal = Record[7];
+        TLM = GetDecodedThreadLocalMode(Record[7]);
 
       bool UnnamedAddr = false;
       if (Record.size() > 8)
@@ -1554,12 +1566,11 @@ bool BitcodeReader::ParseModule(bool Resume) {
 
       GlobalVariable *NewGV =
         new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
-                           isThreadLocal, AddressSpace);
+                           TLM, AddressSpace);
       NewGV->setAlignment(Alignment);
       if (!Section.empty())
         NewGV->setSection(Section);
       NewGV->setVisibility(Visibility);
-      NewGV->setThreadLocal(isThreadLocal);
       NewGV->setUnnamedAddr(UnnamedAddr);
 
       ValueList.push_back(NewGV);
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 333d82ad4a..5b1725f550 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -379,6 +379,17 @@ static unsigned getEncodedVisibility(const GlobalValue *GV) {
   llvm_unreachable("Invalid visibility");
 }
 
+static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
+  switch (GV->getThreadLocalMode()) {
+    case GlobalVariable::NotThreadLocal:         return 0;
+    case GlobalVariable::GeneralDynamicTLSModel: return 1;
+    case GlobalVariable::LocalDynamicTLSModel:   return 2;
+    case GlobalVariable::InitialExecTLSModel:    return 3;
+    case GlobalVariable::LocalExecTLSModel:      return 4;
+  }
+  llvm_unreachable("Invalid TLS model");
+}
+
 // Emit top-level description of module, including target triple, inline asm,
 // descriptors for global variables, and function prototype info.
 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
@@ -487,7 +498,7 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
         GV->getVisibility() != GlobalValue::DefaultVisibility ||
         GV->hasUnnamedAddr()) {
       Vals.push_back(getEncodedVisibility(GV));
-      Vals.push_back(GV->isThreadLocal());
+      Vals.push_back(getEncodedThreadLocalMode(GV));
       Vals.push_back(GV->hasUnnamedAddr());
     } else {
       AbbrevToUse = SimpleGVarAbbrev;
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 7293f3d0e8..afba2e8917 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -684,7 +684,7 @@ bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
   GlobalVariable *NG =
     new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
                        DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
-                       DstGV->isThreadLocal(),
+                       DstGV->getThreadLocalMode(),
                        DstGV->getType()->getAddressSpace());
   
   // Propagate alignment, visibility and section info.
@@ -759,7 +759,7 @@ bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
     new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
                        SGV->isConstant(), SGV->getLinkage(), /*init*/0,
                        SGV->getName(), /*insertbefore*/0,
-                       SGV->isThreadLocal(),
+                       SGV->getThreadLocalMode(),
                        SGV->getType()->getAddressSpace());
   // Propagate alignment, visibility and section info.
   copyGVAttributes(NewDGV, SGV);
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index cd2ebcb508..0ea2a299dd 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -130,6 +130,7 @@ namespace {
   private:
     void printLinkageType(GlobalValue::LinkageTypes LT);
     void printVisibilityType(GlobalValue::VisibilityTypes VisTypes);
+    void printThreadLocalMode(GlobalVariable::ThreadLocalMode TLM);
     void printCallingConv(CallingConv::ID cc);
     void printEscapedString(const std::string& str);
     void printCFP(const ConstantFP* CFP);
@@ -325,6 +326,26 @@ void CppWriter::printVisibilityType(GlobalValue::VisibilityTypes VisType) {
   }
 }
 
+void CppWriter::printThreadLocalMode(GlobalVariable::ThreadLocalMode TLM) {
+  switch (TLM) {
+    case GlobalVariable::NotThreadLocal:
+      Out << "GlobalVariable::NotThreadLocal";
+      break;
+    case GlobalVariable::GeneralDynamicTLSModel:
+      Out << "GlobalVariable::GeneralDynamicTLSModel";
+      break;
+    case GlobalVariable::LocalDynamicTLSModel:
+      Out << "GlobalVariable::LocalDynamicTLSModel";
+      break;
+    case GlobalVariable::InitialExecTLSModel:
+      Out << "GlobalVariable::InitialExecTLSModel";
+      break;
+    case GlobalVariable::LocalExecTLSModel:
+      Out << "GlobalVariable::LocalExecTLSModel";
+      break;
+  }
+}
+
 // printEscapedString - Print each character of the specified string, escaping
 // it if it is not printable or if it is an escape char.
 void CppWriter::printEscapedString(const std::string &Str) {
@@ -996,7 +1017,9 @@ void CppWriter::printVariableHead(const GlobalVariable *GV) {
   }
   if (GV->isThreadLocal()) {
     printCppName(GV);
-    Out << "->setThreadLocal(true);";
+    Out << "->setThreadLocalMode(";
+    printThreadLocalMode(GV->getThreadLocalMode());
+    Out << ");";
     nl(Out);
   }
   if (is_inline) {
diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp
index 6cdab5a266..382571982b 100644
--- a/lib/Target/TargetMachine.cpp
+++ b/lib/Target/TargetMachine.cpp
@@ -77,6 +77,24 @@ CodeModel::Model TargetMachine::getCodeModel() const {
   return CodeGenInfo->getCodeModel();
 }
 
+/// Get the IR-specified TLS model for Var.
+static TLSModel::Model getSelectedTLSModel(const GlobalVariable *Var) {
+  switch (Var->getThreadLocalMode()) {
+  case GlobalVariable::NotThreadLocal:
+    llvm_unreachable("getSelectedTLSModel for non-TLS variable");
+    break;
+  case GlobalVariable::GeneralDynamicTLSModel:
+    return TLSModel::GeneralDynamic;
+  case GlobalVariable::LocalDynamicTLSModel:
+    return TLSModel::LocalDynamic;
+  case GlobalVariable::InitialExecTLSModel:
+    return TLSModel::InitialExec;
+  case GlobalVariable::LocalExecTLSModel:
+    return TLSModel::LocalExec;
+  }
+  llvm_unreachable("invalid TLS model");
+}
+
 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
   // If GV is an alias then use the aliasee for determining
   // thread-localness.
@@ -86,22 +104,31 @@ TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
 
   bool isLocal = Var->hasLocalLinkage();
   bool isDeclaration = Var->isDeclaration();
+  bool isPIC = getRelocationModel() == Reloc::PIC_;
+  bool isPIE = Options.PositionIndependentExecutable;
   // FIXME: what should we do for protected and internal visibility?
   // For variables, is internal different from hidden?
   bool isHidden = Var->hasHiddenVisibility();
 
-  if (getRelocationModel() == Reloc::PIC_ &&
-      !Options.PositionIndependentExecutable) {
+  TLSModel::Model Model;
+  if (isPIC && !isPIE) {
     if (isLocal || isHidden)
-      return TLSModel::LocalDynamic;
+      Model = TLSModel::LocalDynamic;
     else
-      return TLSModel::GeneralDynamic;
+      Model = TLSModel::GeneralDynamic;
   } else {
     if (!isDeclaration || isHidden)
-      return TLSModel::LocalExec;
+      Model = TLSModel::LocalExec;
     else
-      return TLSModel::InitialExec;
+      Model = TLSModel::InitialExec;
   }
+
+  // If the user specified a more specific model, use that.
+  TLSModel::Model SelectedModel = getSelectedTLSModel(Var);
+  if (SelectedModel > Model)
+    return SelectedModel;
+
+  return Model;
 }
 
 /// getOptLevel - Returns the optimization level: None, Less,
@@ -135,4 +162,3 @@ void TargetMachine::setFunctionSections(bool V) {
 void TargetMachine::setDataSections(bool V) {
   DataSections = V;
 }
-
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 1668d6bc16..b192d17134 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -517,7 +517,7 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const TargetData &TD) {
       GlobalVariable *NGV = new GlobalVariable(STy->getElementType(i), false,
                                                GlobalVariable::InternalLinkage,
                                                In, GV->getName()+"."+Twine(i),
-                                               GV->isThreadLocal(),
+                                               GV->getThreadLocalMode(),
                                               GV->getType()->getAddressSpace());
       Globals.insert(GV, NGV);
       NewGlobals.push_back(NGV);
@@ -550,7 +550,7 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const TargetData &TD) {
       GlobalVariable *NGV = new GlobalVariable(STy->getElementType(), false,
                                                GlobalVariable::InternalLinkage,
                                                In, GV->getName()+"."+Twine(i),
-                                               GV->isThreadLocal(),
+                                               GV->getThreadLocalMode(),
                                               GV->getType()->getAddressSpace());
       Globals.insert(GV, NGV);
       NewGlobals.push_back(NGV);
@@ -866,7 +866,7 @@ static GlobalVariable *OptimizeGlobalAddressOfMalloc(GlobalVariable *GV,
                                              UndefValue::get(GlobalType),
                                              GV->getName()+".body",
                                              GV,
-                                             GV->isThreadLocal());
+                                             GV->getThreadLocalMode());
 
   // If there are bitcast users of the malloc (which is typical, usually we have
   // a malloc + bitcast) then replace them with uses of the new global.  Update
@@ -899,7 +899,7 @@ static GlobalVariable *OptimizeGlobalAddressOfMalloc(GlobalVariable *GV,
     new GlobalVariable(Type::getInt1Ty(GV->getContext()), false,
                        GlobalValue::InternalLinkage,
                        ConstantInt::getFalse(GV->getContext()),
-                       GV->getName()+".init", GV->isThreadLocal());
+                       GV->getName()+".init", GV->getThreadLocalMode());
   bool InitBoolUsed = false;
 
   // Loop over all uses of GV, processing them in turn.
@@ -1321,7 +1321,7 @@ static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV, CallInst *CI,
                          PFieldTy, false, GlobalValue::InternalLinkage,
                          Constant::getNullValue(PFieldTy),
                          GV->getName() + ".f" + Twine(FieldNo), GV,
-                         GV->isThreadLocal());
+                         GV->getThreadLocalMode());
     FieldGlobals.push_back(NGV);
 
     unsigned TypeSize = TD->getTypeAllocSize(FieldTy);
@@ -1647,7 +1647,7 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) {
                                              GlobalValue::InternalLinkage,
                                         ConstantInt::getFalse(GV->getContext()),
                                              GV->getName()+".b",
-                                             GV->isThreadLocal());
+                                             GV->getThreadLocalMode());
   GV->getParent()->getGlobalList().insert(GV, NewGV);
 
   Constant *InitVal = GV->getInitializer();
@@ -2054,7 +2054,7 @@ static GlobalVariable *InstallGlobalCtors(GlobalVariable *GCL,
   // Create the new global and insert it next to the existing list.
   GlobalVariable *NGV = new GlobalVariable(CA->getType(), GCL->isConstant(),
                                            GCL->getLinkage(), CA, "",
-                                           GCL->isThreadLocal());
+                                           GCL->getThreadLocalMode());
   GCL->getParent()->getGlobalList().insert(GCL, NGV);
   NGV->takeName(GCL);
 
diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index a9d08db9c6..375a2ae7b0 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -511,7 +511,7 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) {
     // Create a new global variable with enough space for a redzone.
     GlobalVariable *NewGlobal = new GlobalVariable(
         M, NewTy, G->isConstant(), G->getLinkage(),
-        NewInitializer, "", G, G->isThreadLocal());
+        NewInitializer, "", G, G->getThreadLocalMode());
     NewGlobal->copyAttributesFrom(G);
     NewGlobal->setAlignment(RedzoneSize);
 
diff --git a/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index 6c42137b3d..60804794f2 100644
--- a/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -448,7 +448,7 @@ bool GCOVProfiler::emitProfileArcs() {
         new GlobalVariable(*M, CounterTy, false,
                            GlobalValue::InternalLinkage,
                            Constant::getNullValue(CounterTy),
-                           "__llvm_gcov_ctr", 0, false, 0);
+                           "__llvm_gcov_ctr");
       CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
       
       UniqueVector<BasicBlock *> ComplexEdgePreds;
diff --git a/lib/Transforms/Utils/CloneModule.cpp b/lib/Transforms/Utils/CloneModule.cpp
index a0e027b5f1..1dac6b5b8b 100644
--- a/lib/Transforms/Utils/CloneModule.cpp
+++ b/lib/Transforms/Utils/CloneModule.cpp
@@ -53,7 +53,7 @@ Module *llvm::CloneModule(const Module *M, ValueToValueMapTy &VMap) {
                                             I->isConstant(), I->getLinkage(),
                                             (Constant*) 0, I->getName(),
                                             (GlobalVariable*) 0,
-                                            I->isThreadLocal(),
+                                            I->getThreadLocalMode(),
                                             I->getType()->getAddressSpace());
     GV->copyAttributesFrom(I);
     VMap[I] = GV;
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index 4a7fde1905..9147b63512 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -1376,6 +1376,26 @@ static void PrintVisibility(GlobalValue::VisibilityTypes Vis,
   }
 }
 
+static void PrintThreadLocalModel(GlobalVariable::ThreadLocalMode TLM,
+                                  formatted_raw_ostream &Out) {
+  switch (TLM) {
+    case GlobalVariable::NotThreadLocal:
+      break;
+    case GlobalVariable::GeneralDynamicTLSModel:
+      Out << "thread_local ";
+      break;
+    case GlobalVariable::LocalDynamicTLSModel:
+      Out << "thread_local(localdynamic) ";
+      break;
+    case GlobalVariable::InitialExecTLSModel:
+      Out << "thread_local(initialexec) ";
+      break;
+    case GlobalVariable::LocalExecTLSModel:
+      Out << "thread_local(localexec) ";
+      break;
+  }
+}
+
 void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
   if (GV->isMaterializable())
     Out << "; Materializable\n";
@@ -1388,8 +1408,8 @@ void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
 
   PrintLinkage(GV->getLinkage(), Out);
   PrintVisibility(GV->getVisibility(), Out);
+  PrintThreadLocalModel(GV->getThreadLocalMode(), Out);
 
-  if (GV->isThreadLocal()) Out << "thread_local ";
   if (unsigned AddressSpace = GV->getType()->getAddressSpace())
     Out << "addrspace(" << AddressSpace << ") ";
   if (GV->hasUnnamedAddr()) Out << "unnamed_addr ";
diff --git a/lib/VMCore/Core.cpp b/lib/VMCore/Core.cpp
index 30d8a9b12f..972db3cb86 100644
--- a/lib/VMCore/Core.cpp
+++ b/lib/VMCore/Core.cpp
@@ -1210,7 +1210,7 @@ LLVMValueRef LLVMAddGlobalInAddressSpace(LLVMModuleRef M, LLVMTypeRef Ty,
                                          unsigned AddressSpace) {
   return wrap(new GlobalVariable(*unwrap(M), unwrap(Ty), false,
                                  GlobalValue::ExternalLinkage, 0, Name, 0,
-                                 false, AddressSpace));
+                                 GlobalVariable::NotThreadLocal, AddressSpace));
 }
 
 LLVMValueRef LLVMGetNamedGlobal(LLVMModuleRef M, const char *Name) {
diff --git a/lib/VMCore/Globals.cpp b/lib/VMCore/Globals.cpp
index 4254fb29e8..a34ea7040e 100644
--- a/lib/VMCore/Globals.cpp
+++ b/lib/VMCore/Globals.cpp
@@ -80,14 +80,16 @@ bool GlobalValue::isDeclaration() const {
 // GlobalVariable Implementation
 //===----------------------------------------------------------------------===//
 
+// TODO: Remove once clang is updated.
 GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
                                Constant *InitVal, const Twine &Name,
                                bool ThreadLocal, unsigned AddressSpace)
-  : GlobalValue(PointerType::get(Ty, AddressSpace), 
+  : GlobalValue(PointerType::get(Ty, AddressSpace),
                 Value::GlobalVariableVal,
                 OperandTraits<GlobalVariable>::op_begin(this),
                 InitVal != 0, Link, Name),
-    isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) {
+    isConstantGlobal(constant),
+    threadLocalMode(ThreadLocal ? GeneralDynamicTLSModel : NotThreadLocal) {
   if (InitVal) {
     assert(InitVal->getType() == Ty &&
            "Initializer should be the same type as the GlobalVariable!");
@@ -97,16 +99,59 @@ GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
   LeakDetector::addGarbageObject(this);
 }
 
+// TODO: Remove once clang is updated.
 GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
                                LinkageTypes Link, Constant *InitVal,
                                const Twine &Name,
                                GlobalVariable *Before, bool ThreadLocal,
                                unsigned AddressSpace)
+  : GlobalValue(PointerType::get(Ty, AddressSpace),
+                Value::GlobalVariableVal,
+                OperandTraits<GlobalVariable>::op_begin(this),
+                InitVal != 0, Link, Name),
+    isConstantGlobal(constant),
+    threadLocalMode(ThreadLocal ? GeneralDynamicTLSModel : NotThreadLocal) {
+  if (InitVal) {
+    assert(InitVal->getType() == Ty &&
+           "Initializer should be the same type as the GlobalVariable!");
+    Op<0>() = InitVal;
+  }
+
+  LeakDetector::addGarbageObject(this);
+
+  if (Before)
+    Before->getParent()->getGlobalList().insert(Before, this);
+  else
+    M.getGlobalList().push_back(this);
+}
+
+GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
+                               Constant *InitVal, const Twine &Name,
+                               ThreadLocalMode TLMode, unsigned AddressSpace)
+  : GlobalValue(PointerType::get(Ty, AddressSpace),
+                Value::GlobalVariableVal,
+                OperandTraits<GlobalVariable>::op_begin(this),
+                InitVal != 0, Link, Name),
+    isConstantGlobal(constant), threadLocalMode(TLMode) {
+  if (InitVal) {
+    assert(InitVal->getType() == Ty &&
+           "Initializer should be the same type as the GlobalVariable!");
+    Op<0>() = InitVal;
+  }
+
+  LeakDetector::addGarbageObject(this);
+}
+
+GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
+                               LinkageTypes Link, Constant *InitVal,
+                               const Twine &Name,
+                               GlobalVariable *Before, ThreadLocalMode TLMode,
+                               unsigned AddressSpace)
   : GlobalValue(PointerType::get(Ty, AddressSpace), 
                 Value::GlobalVariableVal,
                 OperandTraits<GlobalVariable>::op_begin(this),
                 InitVal != 0, Link, Name),
-    isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) {
+    isConstantGlobal(constant), threadLocalMode(TLMode) {
   if (InitVal) {
     assert(InitVal->getType() == Ty &&
            "Initializer should be the same type as the GlobalVariable!");
diff --git a/lib/VMCore/IRBuilder.cpp b/lib/VMCore/IRBuilder.cpp
index b45923489a..4fc33ff070 100644
--- a/lib/VMCore/IRBuilder.cpp
+++ b/lib/VMCore/IRBuilder.cpp
@@ -28,7 +28,7 @@ Value *IRBuilderBase::CreateGlobalString(StringRef Str, const Twine &Name) {
   Module &M = *BB->getParent()->getParent();
   GlobalVariable *GV = new GlobalVariable(M, StrConstant->getType(),
                                           true, GlobalValue::PrivateLinkage,
-                                          StrConstant, "", 0, false);
+                                          StrConstant);
   GV->setName(Name);
   GV->setUnnamedAddr(true);
   return GV;