[llvm] MC: Restructure MCFragment as a fixed part and a variable tail (PR #148544)

[Steven Wu via llvm-commits]

cachemeifyoucan wrote:

> I apologize for any disruption in the MC layer. The integrated assembler was previously poorly designed and very inefficient. Over the past two years, I've significantly overhauled the relocation generation process.


I am generally in favor of the changes you made but the way the patch landed is actually making downstream changes really hard to maintain. Do you have a RFC somewhere to describe the changes you want to make? Or for my own interest, is the changes on the MCFragment classes are all done?

https://github.com/llvm/llvm-project/pull/148544