[llvm] [CodeGen] Distinguish zero-sized call frames from no call frame in MachineBB (PR #106964)

[Fabian Ritter via llvm-commits]

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@@ -282,6 +284,10 @@ class MachineFrameInfo {
   /// It is only valid during and after prolog/epilog code insertion.
   uint64_t MaxCallFrameSize = ~UINT64_C(0);
 
+  /// Call frame sizes for the MachineFunction's MachineBasicBlocks. This is set
+  /// by the MachineFrameSizeInfo constructor and cleared by its destructor.
+  MachineFrameSizeInfo *SizeInfo = nullptr;
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ritter-x2a wrote:

The motivation for that was to make passing this info to `X86TargetLowering::EmitLoweredTLSAddr` less obtrusive in #106965. For this PR here, it's certainly not necessary. I can move this change over to the other PR for now and then we can discuss there how else to pass it to the function (or decide on a different way to avoid the nested CALLSEQs for TLSAddrs).

https://github.com/llvm/llvm-project/pull/106964