[clang] [lld] [llvm] [WebAssembly] Cooperative threading for WASIP3 (PR #200855)

[Sy Brand via cfe-commits]

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@@ -283,10 +283,17 @@ class CoalesceFeaturesAndStripAtomics final : public ModulePass {
     bool StrippedAtomics = false;
     bool StrippedTLS = false;
 
+    // In cooperative threading mode, thread locals are meaningful even without
+    // atomics.
+    bool CooperativeThreading =
+        WasmTM->getSubtargetImpl()->hasCooperativeMultithreading();
+
     if (!Features[WebAssembly::FeatureAtomics]) {
       StrippedAtomics = stripAtomics(M);
-      StrippedTLS = stripThreadLocals(M);
-    } else if (!Features[WebAssembly::FeatureBulkMemory]) {
+      if (!CooperativeThreading)
+        StrippedTLS = stripThreadLocals(M);
+    }
+    if (!Features[WebAssembly::FeatureBulkMemory]) {
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TartanLlama wrote:

The only difference in behaviour is in the `CooperativeThreading` case, which now does not strip thread locals in the `!atomics` case, but still does in the `!bulk_memory` case. The latter was the reason for removing the `else`. 

https://github.com/llvm/llvm-project/pull/200855