Implement .cfi_undefined. Based on a patch from PaX team, updated by

Roman Divacky. I just added the testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168520 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 3 insertions, 2 deletions

diff --git a/include/llvm/MC/MCDwarf.h b/include/llvm/MC/MCDwarf.h
index 8fc437f3e6..6fa41ae67c 100644
--- a/include/llvm/MC/MCDwarf.h
+++ b/include/llvm/MC/MCDwarf.h
@@ -267,7 +267,7 @@ namespace llvm {
   class MCCFIInstruction {
   public:
     enum OpType { SameValue, RememberState, RestoreState, Move, RelMove, Escape,
-                  Restore};
+                  Restore, Undefined };
   private:
     OpType Operation;
     MCSymbol *Label;
@@ -282,7 +282,7 @@ namespace llvm {
     }
     MCCFIInstruction(OpType Op, MCSymbol *L, unsigned Register)
       : Operation(Op), Label(L), Destination(Register) {
-      assert(Op == SameValue || Op == Restore);
+      assert(Op == SameValue || Op == Restore || Op == Undefined);
     }
     MCCFIInstruction(MCSymbol *L, const MachineLocation &D,
                      const MachineLocation &S)
diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h
index 230d27ef2e..b5c8008cd6 100644
--- a/include/llvm/MC/MCStreamer.h
+++ b/include/llvm/MC/MCStreamer.h
@@ -515,6 +515,7 @@ namespace llvm {
     virtual void EmitCFIAdjustCfaOffset(int64_t Adjustment);
     virtual void EmitCFIEscape(StringRef Values);
     virtual void EmitCFISignalFrame();
+    virtual void EmitCFIUndefined(int64_t Register);
 
     virtual void EmitWin64EHStartProc(const MCSymbol *Symbol);
     virtual void EmitWin64EHEndProc();