Index: cfe/trunk/include/clang/Basic/BuiltinsWebAssembly.def
===================================================================
--- cfe/trunk/include/clang/Basic/BuiltinsWebAssembly.def
+++ cfe/trunk/include/clang/Basic/BuiltinsWebAssembly.def
@@ -31,6 +31,7 @@
 
 // Thread-local storage
 TARGET_BUILTIN(__builtin_wasm_tls_size, "z", "nc", "bulk-memory")
+TARGET_BUILTIN(__builtin_wasm_tls_base, "v*", "n", "bulk-memory")
 
 // Floating point min/max
 BUILTIN(__builtin_wasm_min_f32, "fff", "nc")
Index: cfe/trunk/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGBuiltin.cpp
+++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp
@@ -13924,6 +13924,10 @@
     Function *Callee = CGM.getIntrinsic(Intrinsic::wasm_tls_size, ResultType);
     return Builder.CreateCall(Callee);
   }
+  case WebAssembly::BI__builtin_wasm_tls_base: {
+    Function *Callee = CGM.getIntrinsic(Intrinsic::wasm_tls_base);
+    return Builder.CreateCall(Callee);
+  }
   case WebAssembly::BI__builtin_wasm_throw: {
     Value *Tag = EmitScalarExpr(E->getArg(0));
     Value *Obj = EmitScalarExpr(E->getArg(1));
Index: cfe/trunk/test/CodeGen/builtins-wasm.c
===================================================================
--- cfe/trunk/test/CodeGen/builtins-wasm.c
+++ cfe/trunk/test/CodeGen/builtins-wasm.c
@@ -44,6 +44,11 @@
   // WEBASSEMBLY64: call i64 @llvm.wasm.tls.size.i64()
 }
 
+void *tls_base() {
+  return __builtin_wasm_tls_base();
+  // WEBASSEMBLY: call i8* @llvm.wasm.tls.base()
+}
+
 void throw(void *obj) {
   return __builtin_wasm_throw(0, obj);
   // WEBASSEMBLY32: call void @llvm.wasm.throw(i32 0, i8* %{{.*}})
Index: llvm/trunk/include/llvm/IR/IntrinsicsWebAssembly.td
===================================================================
--- llvm/trunk/include/llvm/IR/IntrinsicsWebAssembly.td
+++ llvm/trunk/include/llvm/IR/IntrinsicsWebAssembly.td
@@ -133,4 +133,9 @@
             [],
             [IntrNoMem, IntrSpeculatable]>;
 
+def int_wasm_tls_base :
+  Intrinsic<[llvm_ptr_ty],
+            [],
+            [IntrReadMem]>;
+
 } // TargetPrefix = "wasm"
Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
@@ -227,6 +227,23 @@
     }
     break;
   }
+  case ISD::INTRINSIC_W_CHAIN: {
+    unsigned IntNo = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
+    switch (IntNo) {
+    case Intrinsic::wasm_tls_base: {
+      MVT PtrVT = TLI->getPointerTy(CurDAG->getDataLayout());
+      assert(PtrVT == MVT::i32 && "only wasm32 is supported for now");
+
+      MachineSDNode *TLSBase = CurDAG->getMachineNode(
+          WebAssembly::GLOBAL_GET_I32, DL, MVT::i32,
+          CurDAG->getTargetExternalSymbol("__tls_base", PtrVT),
+          Node->getOperand(0));
+      ReplaceNode(Node, TLSBase);
+      return;
+    }
+    }
+    break;
+  }
 
   default:
     break;
Index: llvm/trunk/test/CodeGen/WebAssembly/tls-general-dynamic.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/tls-general-dynamic.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/tls-general-dynamic.ll
@@ -75,6 +75,15 @@
   ret i32 %1
 }
 
+; CHECK-LABEL: tls_base:
+; CHECK-NEXT: .functype tls_base () -> (i32)
+define i8* @tls_base() {
+; CHECK-NEXT: global.get __tls_base
+; CHECK-NEXT: return
+  %1 = call i8* @llvm.wasm.tls.base()
+  ret i8* %1
+}
+
 ; CHECK: .type tls,@object
 ; TLS-NEXT: .section .tbss.tls,"",@
 ; NO-TLS-NEXT: .section .bss.tls,"",@
@@ -84,3 +93,4 @@
 @tls = internal thread_local global i32 0
 
 declare i32 @llvm.wasm.tls.size.i32()
+declare i8* @llvm.wasm.tls.base()