[llvm] [PowerPC] Support local-dynamic TLS relocation on AIX (PR #66316)

[Amy Kwan via llvm-commits]

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@@ -231,12 +231,18 @@ class PPCTargetAsmStreamer : public PPCTargetStreamer {
       MCSymbolXCOFF *TCSym =
           cast<MCSectionXCOFF>(Streamer.getCurrentSectionOnly())
               ->getQualNameSymbol();
-      // On AIX, we have a region handle (symbol at m) and the variable offset
-      // (symbol@{gd|ie|le}) for TLS variables, depending on the TLS model.
+      // On AIX, we have TLS variable offsets (symbol@({gd|ie|le|ld}) depending
+      // on the TLS access method (or model). For the general-dynamic access
+      // method, we also have region handle (symbol at m) for each variable. For
+      // local-dynamic, a module handle (__TLSML[TC]@ml) for all variables. For
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amy-kwan wrote:

```suggestion
      // local-dynamic, there is a module handle (__TLSML[TC]@ml) for all variables. Finally, for
```

https://github.com/llvm/llvm-project/pull/66316