[llvm] [AArch64] Emit .arch and .arch_extension during assembly to textual asm (PR #138433)

[Sam Elliott via llvm-commits]

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@@ -7234,6 +7236,8 @@ bool AArch64AsmParser::parseDirectiveArchExtension(SMLoc L) {
     STI.ClearFeatureBitsTransitively(It->Features);
   FeatureBitset Features = ComputeAvailableFeatures(STI.getFeatureBits());
   setAvailableFeatures(Features);
+
+  getTargetStreamer().emitDirectiveArchExtension(Name);
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lenary wrote:

This is wrong, as `Name` might have been updated on (new) line 7222. This would be clear with a `.arch_extension nolse` test.

https://github.com/llvm/llvm-project/pull/138433