[llvm] [AArch64] Null check TargetStreamer before emitting .variant_pcs (PR #138924)

[Sander de Smalen via llvm-commits]

================
@@ -1372,7 +1372,8 @@ void AArch64AsmPrinter::emitFunctionEntryLabel() {
       MF->getInfo<AArch64FunctionInfo>()->isSVECC()) {
     auto *TS =
         static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
-    TS->emitDirectiveVariantPCS(CurrentFnSym);
+    if (TS)
+      TS->emitDirectiveVariantPCS(CurrentFnSym);
----------------
sdesmalen-arm wrote:

```suggestion
    if (auto *TS =
         static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer()))
      TS->emitDirectiveVariantPCS(CurrentFnSym);
```

https://github.com/llvm/llvm-project/pull/138924