[llvm] [ARM] Move MCStreamer::emitThumbFunc to ARMTargetStreamer (PR #126199)

[Fangrui Song via llvm-commits]

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@@ -81,6 +80,7 @@ class MCObjectStreamer : public MCStreamer {
   bool isIntegratedAssemblerRequired() const override { return true; }
 
   void emitFrames(MCAsmBackend *MAB);
+  MCSymbol *emitCFILabel() override;
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MaskRay wrote:

Making the function public is intentional as mentioned by the description:

> emitCFILabel, called by ARMWinCOFFStreamer.cpp, has to be made public.

In the call site, the previous `getParser().getStreamer().emitThumbFunc(Symbol);` somehow was able to access `emitThumbFunc`, despite it being private. Perhaps there was a `friend` somewhere.

The new `getTargetStreamer().emitThumbFunc(Symbol);` does require `emitThumbFunc` to be public.

https://github.com/llvm/llvm-project/pull/126199