[NativeAOT-LLVM] Workaround to align thread statics to 8 byte boundary (

#2609)

* workaround to align thread statics to 8 byte boundary

* add test for thread static alignment

src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/ThreadStatics.cs

@@ -137,7 +137,13 @@ private static unsafe object AllocateThreadStaticStorageForType(TypeManagerHandl
  gcDesc = Internal.Runtime.Augments.RuntimeAugments.TypeLoaderCallbacks.GetThreadStaticGCDescForDynamicType(typeManager, typeTlsIndex);
  }
 
+#if TARGET_WASM
+ // TODO-LLVM: Remove when there is an upstream fix. See https://github.com/dotnet/runtimelab/issues/2606 and https://github.com/dotnet/runtime/issues/103234
+ // This is a fix for aligning to 8, thread static fields that should be aligned 8, we just conservatively align everything to 8.
+ return InternalCalls.RhpNewFastAlign8((MethodTable*)gcDesc);
+#else
  return RuntimeImports.RhNewObject((MethodTable*)gcDesc);
+#endif
  }
  }
 }

src/tests/nativeaot/SmokeTests/HelloWasm/HelloWasm.cs

@@ -429,6 +429,8 @@ private static unsafe int Main(string[] args)
 
  LSSATests.Run();
 
+ TestThreadStaticAlignment();
+
  if (OperatingSystem.IsBrowser())
  {
  EventLoopTestClass.TestEventLoopIntegration();
@@ -4251,6 +4253,49 @@ static void TestGenStructContains()
  EndTest(contains);
  }
 
+ [InlineArray(3)]
+ internal struct ReturnArea
+ {
+ private ulong buffer;
+
+ internal unsafe nint AddressOfReturnArea()
+ {
+ return (nint)Unsafe.AsPointer(ref buffer);
+ }
+ }
+
+ internal class ThreadStaticAlignCheck1
+ {
+ [ThreadStatic]
+ [FixedAddressValueType]
+ internal static ReturnArea returnArea = default;
+ }
+
+ internal class Padder
+ {
+ private object o1;
+ }
+
+ internal class ThreadStaticAlignCheck2
+ {
+ [ThreadStatic]
+ [FixedAddressValueType]
+ internal static ReturnArea returnArea = default;
+ }
+
+ static void TestThreadStaticAlignment()
+ {
+ StartTest("Test ThreadStatic Alignment");
+
+ // Assume that these are allocated sequentially, use a padding object of size 12 ( mod 8 is not 0 ) to move the alignment of the second AddressOfReturnArea in case the first is
+ // coincidentally aligned 8.
+ var ts1Addr = ThreadStaticAlignCheck1.returnArea.AddressOfReturnArea();
+ var p = new Padder();
+ var ts2Addr = ThreadStaticAlignCheck2.returnArea.AddressOfReturnArea();
+
+ EndTest((((nint)ts1Addr) % 8 == 0) && (((nint)ts2Addr) % 8 == 0));
+ }
+
  static ushort ReadUInt16()
  {
  // something with MSB set