[llvm] Overhaul the TargetMachine and LLVMTargetMachine Classes (PR #111234)

[Matt Arsenault via llvm-commits]

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@@ -256,7 +256,7 @@ struct LandingPadInfo {
 
 class LLVM_ABI MachineFunction {
   Function &F;
-  const LLVMTargetMachine &Target;
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arsenm wrote:

If you're in MachineFunction, you are definitely using CodeGen. So why wouldn't MachineFunction reference the lowest common subclass for codegen? 

https://github.com/llvm/llvm-project/pull/111234