MachO: Add linker-optimisation hint framework to MC.

Another part of the ARM64 backend (so tests will be following soon).
This is currently used by the linker to relax adrp/ldr pairs into nops
where possible, though could well be more broadly applicable.

llvm-svn: 205084

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 742f7846496..7e437f4bcb8 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -17,6 +17,7 @@
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCLinkerOptimizationHint.h"
 #include "llvm/MC/MCMachOSymbolFlags.h"
 #include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCObjectStreamer.h"
@@ -104,6 +105,10 @@ public:
     llvm_unreachable("macho doesn't support this directive");
   }
 
+  void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override {
+    getAssembler().getLOHContainer().addDirective(Kind, Args);
+  }
+
   void FinishImpl() override;
 };