[llvm] MCFragment: Use trailing data for fixed-size part (PR #150846)

[Alexis Engelke via llvm-commits]

================
@@ -1034,37 +1034,43 @@ MCELFStreamer &MipsTargetELFStreamer::getStreamer() {
 
 void MipsTargetELFStreamer::emitGPRel32Value(const MCExpr *Value) {
   auto &S = getStreamer();
+  S.ensureHeadroom(4);
----------------
aengelke wrote:

This looks like some kind of change that can easily cause hard-to-diagnose bugs when missed. This seems hard to catch with assertions, though, and I've no good idea how to improve this.

https://github.com/llvm/llvm-project/pull/150846