[WebAssembly] Fix __builtin_wasm_tls_base intrinsic

Summary:
Properly generate the outchain for the `__builtin_wasm_tls_base` intrinsic.

Also marked the intrinsic pure, per @sunfish's suggestion.

Reviewers: tlively, aheejin, sbc100, sunfish

Reviewed By: tlively

Subscribers: dschuff, jgravelle-google, hiraditya, cfe-commits, llvm-commits, sunfish

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64949

llvm-svn: 366499

clang/include/clang/Basic/BuiltinsWebAssembly.def

@@ -31,7 +31,7 @@ TARGET_BUILTIN(__builtin_wasm_data_drop, "vIUi", "", "bulk-memory")
 
 // Thread-local storage
 TARGET_BUILTIN(__builtin_wasm_tls_size, "z", "nc", "bulk-memory")
-TARGET_BUILTIN(__builtin_wasm_tls_base, "v*", "n", "bulk-memory")
+TARGET_BUILTIN(__builtin_wasm_tls_base, "v*", "nU", "bulk-memory")
 
 // Floating point min/max
 BUILTIN(__builtin_wasm_min_f32, "fff", "nc")

llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp

@@ -235,7 +235,7 @@ void WebAssemblyDAGToDAGISel::Select(SDNode *Node) {
       assert(PtrVT == MVT::i32 && "only wasm32 is supported for now");
 
       MachineSDNode *TLSBase = CurDAG->getMachineNode(
-          WebAssembly::GLOBAL_GET_I32, DL, MVT::i32,
+          WebAssembly::GLOBAL_GET_I32, DL, MVT::i32, MVT::Other,
           CurDAG->getTargetExternalSymbol("__tls_base", PtrVT),
           Node->getOperand(0));
       ReplaceNode(Node, TLSBase);

llvm/test/CodeGen/WebAssembly/tls-general-dynamic.ll

@@ -84,6 +84,17 @@ define i8* @tls_base() {
   ret i8* %1
 }
 
+; CHECK-LABEL: tls_base_write:
+; CHECK-NEXT: .functype tls_base_write (i32) -> ()
+define void @tls_base_write(i8** %output) {
+; CHECK-NEXT: global.get __tls_base
+; CHECK-NEXT: i32.store 0
+; CHECK-NEXT: return
+  %1 = call i8* @llvm.wasm.tls.base()
+  store i8* %1, i8** %output
+  ret void
+}
+
 ; CHECK: .type tls,@object
 ; TLS-NEXT: .section .tbss.tls,"",@
 ; NO-TLS-NEXT: .section .bss.tls,"",@