From f0841b025939d7de3027f7e3548451263b44a34f Mon Sep 17 00:00:00 2001
From: Iain Sandoe <iain@sandoe.co.uk>
Date: Sun, 12 Aug 2018 14:46:07 +0100
Subject: [PATCH] [llvm, DWARF. CFI] Emit DW_CFA_restore_extended when
 register # exceeds 64.

The DW_CFA_restore operation has only 6 bits for the register number, emit a DW_CFA_restore_extended when we exceed this.
---
 llvm/lib/MC/MCDwarf.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 0461c2564cc..e6d3751e583 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -1421,8 +1421,12 @@ void FrameEmitterImpl::EmitCFIInstruction(const MCCFIInstruction &Instr) {
     unsigned Reg = Instr.getRegister();
     if (!IsEH)
       Reg = MRI->getDwarfRegNumFromDwarfEHRegNum(Reg);
-    Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
-    return;
+    if (Reg < 64) {
+      Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
+    } else {
+      Streamer.EmitIntValue(dwarf::DW_CFA_restore_extended, 1);
+      Streamer.EmitULEB128IntValue(Reg);
+    }    return;
   }
   case MCCFIInstruction::OpGnuArgsSize:
     Streamer.EmitIntValue(dwarf::DW_CFA_GNU_args_size, 1);