MC: When running with -mc-relax-all, we can eagerly relax instructions and avoid creating unnecessary MCInstFragments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104736 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 2f23ae3..27e4e98 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -463,23 +463,25 @@
CurSectionData->setHasInstructions(true);
- // See if we might need to relax this instruction, if so it needs its own
- // fragment.
- //
- // FIXME-PERF: Support target hook to do a fast path that avoids the encoder,
- // when we can immediately tell that we will get something which might need
- // relaxation (and compute its size).
- //
- // FIXME-PERF: We should also be smart about immediately relaxing instructions
- // which we can already show will never possibly fit (we can also do a very
- // good job of this before we do the first relaxation pass, because we have
- // total knowledge about undefined symbols at that point). Even now, though,
- // we can do a decent job, especially on Darwin where scattering means that we
- // are going to often know that we can never fully resolve a fixup.
- if (Assembler.getBackend().MayNeedRelaxation(Inst))
- EmitInstToFragment(Inst);
- else
+ // If this instruction doesn't need relaxation, just emit it as data.
+ if (!Assembler.getBackend().MayNeedRelaxation(Inst)) {
EmitInstToData(Inst);
+ return;
+ }
+
+ // Otherwise, if we are relaxing everything, relax the instruction as much as
+ // possible and emit it as data.
+ if (Assembler.getRelaxAll()) {
+ MCInst Relaxed;
+ Assembler.getBackend().RelaxInstruction(Inst, Relaxed);
+ while (Assembler.getBackend().MayNeedRelaxation(Relaxed))
+ Assembler.getBackend().RelaxInstruction(Relaxed, Relaxed);
+ EmitInstToData(Relaxed);
+ return;
+ }
+
+ // Otherwise emit to a separate fragment.
+ EmitInstToFragment(Inst);
}
void MCMachOStreamer::Finish() {