First draft of stack slot loads / stores lowering

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70735 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/MSP430/MSP430InstrInfo.cpp

@@ -16,10 +16,10 @@
 #include "MSP430TargetMachine.h"
 #include "MSP430GenInstrInfo.inc"
 #include "llvm/Function.h"
-#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
-
+#include "llvm/CodeGen/PseudoSourceValue.h"
 
 using namespace llvm;
 
@@ -27,6 +27,42 @@ MSP430InstrInfo::MSP430InstrInfo(MSP430TargetMachine &tm)
   : TargetInstrInfoImpl(MSP430Insts, array_lengthof(MSP430Insts)),
     RI(tm, *this), TM(tm) {}
 
+void MSP430InstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
+                                          MachineBasicBlock::iterator MI,
+                                    unsigned SrcReg, bool isKill, int FrameIdx,
+                                    const TargetRegisterClass *RC) const {
+  DebugLoc DL = DebugLoc::getUnknownLoc();
+  if (MI != MBB.end()) DL = MI->getDebugLoc();
+
+  if (RC == &MSP430::GR16RegClass)
+    BuildMI(MBB, MI, DL, get(MSP430::MOV16mr))
+      .addFrameIndex(FrameIdx).addImm(0)
+      .addReg(SrcReg, false, false, isKill);
+  else if (RC == &MSP430::GR8RegClass)
+    BuildMI(MBB, MI, DL, get(MSP430::MOV8mr))
+      .addFrameIndex(FrameIdx).addImm(0)
+      .addReg(SrcReg, false, false, isKill);
+  else
+    assert(0 && "Cannot store this register to stack slot!");
+}
+
+void MSP430InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
+                                           MachineBasicBlock::iterator MI,
+                                           unsigned DestReg, int FrameIdx,
+                                           const TargetRegisterClass *RC) const{
+  DebugLoc DL = DebugLoc::getUnknownLoc();
+  if (MI != MBB.end()) DL = MI->getDebugLoc();
+
+  if (RC == &MSP430::GR16RegClass)
+    BuildMI(MBB, MI, DL, get(MSP430::MOV16rm))
+      .addReg(DestReg).addFrameIndex(FrameIdx).addImm(0);
+  else if (RC == &MSP430::GR8RegClass)
+    BuildMI(MBB, MI, DL, get(MSP430::MOV8rm))
+      .addReg(DestReg).addFrameIndex(FrameIdx).addImm(0);
+  else
+    assert(0 && "Cannot store this register to stack slot!");
+}
+
 bool MSP430InstrInfo::copyRegToReg(MachineBasicBlock &MBB,
                                    MachineBasicBlock::iterator I,
                                    unsigned DestReg, unsigned SrcReg,

lib/Target/MSP430/MSP430InstrInfo.h

@@ -41,6 +41,15 @@ public:
   bool isMoveInstr(const MachineInstr& MI,
                    unsigned &SrcReg, unsigned &DstReg,
                    unsigned &SrcSubIdx, unsigned &DstSubIdx) const;
+
+  virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
+                                   MachineBasicBlock::iterator MI,
+                                   unsigned SrcReg, bool isKill, int FrameIndex,
+                                   const TargetRegisterClass *RC) const;
+  virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
+                                    MachineBasicBlock::iterator MI,
+                                    unsigned DestReg, int FrameIdx,
+                                    const TargetRegisterClass *RC) const;
 };
 
 }

lib/Target/MSP430/MSP430RegisterInfo.cpp

@@ -74,6 +74,11 @@ MSP430RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   return Reserved;
 }
 
+const TargetRegisterClass* MSP430RegisterInfo::getPointerRegClass() const {
+  return &MSP430::GR16RegClass;
+}
+
+
 bool MSP430RegisterInfo::hasFP(const MachineFunction &MF) const {
   return NoFramePointerElim || MF.getFrameInfo()->hasVarSizedObjects();
 }
@@ -143,7 +148,32 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
 void
 MSP430RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
                                         int SPAdj, RegScavenger *RS) const {
-  assert(0 && "Not implemented yet!");
+  assert(SPAdj == 0 && "Unexpected");
+
+  unsigned i = 0;
+  MachineInstr &MI = *II;
+  MachineFunction &MF = *MI.getParent()->getParent();
+  while (!MI.getOperand(i).isFI()) {
+    ++i;
+    assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
+  }
+
+  int FrameIndex = MI.getOperand(i).getIndex();
+
+  unsigned BasePtr = (hasFP(MF) ? MSP430::FPW : MSP430::SPW);
+  int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
+
+  if (!hasFP(MF))
+    Offset += MF.getFrameInfo()->getStackSize();
+
+  // Skip the saved PC
+  Offset += 2;
+
+  MI.getOperand(i).ChangeToRegister(BasePtr, false);
+
+  // Fold imm into offset
+  Offset += MI.getOperand(i+1).getImm();
+  MI.getOperand(i+1).ChangeToImmediate(Offset);
 }
 
 void MSP430RegisterInfo::emitPrologue(MachineFunction &MF) const {

lib/Target/MSP430/MSP430RegisterInfo.h

@@ -40,6 +40,7 @@ public:
     getCalleeSavedRegClasses(const MachineFunction *MF = 0) const;
 
   BitVector getReservedRegs(const MachineFunction &MF) const;
+  const TargetRegisterClass* getPointerRegClass() const;
 
   bool hasFP(const MachineFunction &MF) const;
   bool hasReservedCallFrame(MachineFunction &MF) const;

lib/Target/MSP430/MSP430TargetMachine.cpp

@@ -41,7 +41,7 @@ MSP430TargetMachine::MSP430TargetMachine(const Module &M,
   // FIXME: Check TargetData string.
   DataLayout("e-p:16:8:8-i8:8:8-i16:8:8-i32:8:8"),
   InstrInfo(*this), TLInfo(*this),
-  FrameInfo(TargetFrameInfo::StackGrowsUp, 8, 0) { }
+  FrameInfo(TargetFrameInfo::StackGrowsDown, 8, 0) { }
 
 const TargetAsmInfo *MSP430TargetMachine::createTargetAsmInfo() const {
   return new MSP430TargetAsmInfo(*this);