WebAssembly: Remove threadlocal_address intrinsics when disabling TLS

Author: MatzeB

llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp

@@ -289,6 +289,19 @@ class CoalesceFeaturesAndStripAtomics final : public ModulePass {
 
   bool stripThreadLocals(Module &M) {
     bool Stripped = false;
+    for (auto &F : M) {
+      for (auto &B : F) {
+        for (auto &I : make_early_inc_range(B)) {
+          if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I)) {
+            if (II->getIntrinsicID() == Intrinsic::threadlocal_address) {
+              II->replaceAllUsesWith(II->getArgOperand(0));
+              II->eraseFromParent();
+              Stripped = true;
+            }
+          }
+        }
+      }
+    }
     for (auto &GV : M.globals()) {
       if (GV.isThreadLocal()) {
         Stripped = true;

llvm/test/CodeGen/WebAssembly/strip-tls.ll

@@ -0,0 +1,28 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc -o - %s -mattr=-bulk-memory | FileCheck --check-prefix=NOTLS %s
+; RUN: llc -o - %s -mattr=+bulk-memory,+atomics | FileCheck --check-prefix=TLS %s
+
+target triple = "wasm32--"
+
+@tls = internal thread_local global i32 0
+
+define i32 @func() {
+; NOTLS-LABEL: func:
+; NOTLS:         .functype func () -> (i32)
+; NOTLS-NEXT:  # %bb.0:
+; NOTLS-NEXT:    i32.const 0
+; NOTLS-NEXT:    i32.load tls
+; NOTLS-NEXT:    # fallthrough-return
+;
+; TLS-LABEL: func:
+; TLS:         .functype func () -> (i32)
+; TLS-NEXT:  # %bb.0:
+; TLS-NEXT:    global.get __tls_base
+; TLS-NEXT:    i32.const tls@TLSREL
+; TLS-NEXT:    i32.add
+; TLS-NEXT:    i32.load 0
+; TLS-NEXT:    # fallthrough-return
+  %p = call ptr @llvm.threadlocal.address.p0(ptr @tls)
+  %v = load i32, ptr %p
+  ret i32 %v
+}