ARM IAS: support .movsp

.movsp is an ARM unwinding directive that indicates to the unwinder that a
register contains an offset from the current stack pointer.  If the offset is
unspecified, it defaults to zero.

llvm-svn: 200449
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index c2e3503..151d48d 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -123,6 +123,7 @@
   virtual void emitPersonalityIndex(unsigned Index);
   virtual void emitHandlerData();
   virtual void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0);
+  virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
   virtual void emitPad(int64_t Offset);
   virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
                            bool isVector);
@@ -172,6 +173,16 @@
     OS << ", #" << Offset;
   OS << '\n';
 }
+void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
+  assert((Reg != ARM::SP && Reg != ARM::PC) &&
+         "the operand of .movsp cannot be either sp or pc");
+
+  OS << "\t.movsp\t";
+  InstPrinter.printRegName(OS, Reg);
+  if (Offset)
+    OS << ", #" << Offset;
+  OS << '\n';
+}
 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
   OS << "\t.pad\t#" << Offset << '\n';
 }
@@ -387,6 +398,7 @@
   virtual void emitPersonalityIndex(unsigned Index);
   virtual void emitHandlerData();
   virtual void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0);
+  virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
   virtual void emitPad(int64_t Offset);
   virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
                            bool isVector);
@@ -448,6 +460,7 @@
   void emitPersonalityIndex(unsigned index);
   void emitHandlerData();
   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
+  void emitMovSP(unsigned Reg, int64_t Offset = 0);
   void emitPad(int64_t Offset);
   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
@@ -657,6 +670,9 @@
                                      int64_t Offset) {
   getStreamer().emitSetFP(FpReg, SpReg, Offset);
 }
+void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
+  getStreamer().emitMovSP(Reg, Offset);
+}
 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
   getStreamer().emitPad(Offset);
 }
@@ -1203,6 +1219,20 @@
     FPOffset += Offset;
 }
 
+void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
+  assert((Reg != ARM::SP && Reg != ARM::PC) &&
+         "the operand of .movsp cannot be either sp or pc");
+  assert(FPReg == ARM::SP && "current FP must be SP");
+
+  FlushPendingOffset();
+
+  FPReg = Reg;
+  FPOffset = SPOffset + Offset;
+
+  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
+  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
+}
+
 void ARMELFStreamer::emitPad(int64_t Offset) {
   // Track the change of the $sp offset
   SPOffset -= Offset;