[llvm-branch-commits] [llvm] [llvm-21][MC] Fix fragments for sections bigger than 4G (PR #169121)

[Fangrui Song via llvm-branch-commits]

MaskRay wrote:

`MCFragment` is an internal class for the LLVM integrated assembler. It's in `llvm/include/llvm/MC/` specifically to allow access from llvm/lib/Target/XXX. Other components don't use `MCFragment`. 

This PR modifies `MCEncodedFragment` (which is not in main), affecting `MCDataFragment`.
I believe the only breakage is:
A downstream backend might be built against an older 21.x release, getting accesses relative to MCEncodedFragment offsets through some MCEncodedFragment inline functions.
If the backend is later linked against with a newer 21.x release, the changed offsets could cause a breakage. I think downstream backend developers would not upgrade libLLVM without rebuilding the downstream backend.


https://github.com/llvm/llvm-project/pull/169121