First step of huge frame-related refactoring: move emit{Prologue,Epilogue} out of TargetRegisterInfo to TargetFrameInfo, which is definitely much better suitable place

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119097 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/MSP430/MSP430FrameInfo.cpp b/lib/Target/MSP430/MSP430FrameInfo.cpp
new file mode 100644
index 0000000..42a44a7
--- /dev/null
+++ b/lib/Target/MSP430/MSP430FrameInfo.cpp
@@ -0,0 +1,168 @@
+//=======- MSP430FrameInfo.cpp - MSP430 Frame Information ------*- C++ -*-====//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the MSP430 implementation of TargetFrameInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MSP430FrameInfo.h"
+#include "MSP430InstrInfo.h"
+#include "MSP430MachineFunctionInfo.h"
+#include "llvm/Function.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
+
+using namespace llvm;
+
+void MSP430FrameInfo::emitPrologue(MachineFunction &MF) const {
+  MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
+  const MSP430RegisterInfo *RegInfo =
+    static_cast<const MSP430RegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const MSP430InstrInfo &TII =
+    *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
+
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+
+  // Get the number of bytes to allocate from the FrameInfo.
+  uint64_t StackSize = MFI->getStackSize();
+
+  uint64_t NumBytes = 0;
+  if (RegInfo->hasFP(MF)) {
+    // Calculate required stack adjustment
+    uint64_t FrameSize = StackSize - 2;
+    NumBytes = FrameSize - MSP430FI->getCalleeSavedFrameSize();
+
+    // Get the offset of the stack slot for the EBP register... which is
+    // guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
+    // Update the frame offset adjustment.
+    MFI->setOffsetAdjustment(-NumBytes);
+
+    // Save FPW into the appropriate stack slot...
+    BuildMI(MBB, MBBI, DL, TII.get(MSP430::PUSH16r))
+      .addReg(MSP430::FPW, RegState::Kill);
+
+    // Update FPW with the new base value...
+    BuildMI(MBB, MBBI, DL, TII.get(MSP430::MOV16rr), MSP430::FPW)
+      .addReg(MSP430::SPW);
+
+    // Mark the FramePtr as live-in in every block except the entry.
+    for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
+         I != E; ++I)
+      I->addLiveIn(MSP430::FPW);
+
+  } else
+    NumBytes = StackSize - MSP430FI->getCalleeSavedFrameSize();
+
+  // Skip the callee-saved push instructions.
+  while (MBBI != MBB.end() && (MBBI->getOpcode() == MSP430::PUSH16r))
+    ++MBBI;
+
+  if (MBBI != MBB.end())
+    DL = MBBI->getDebugLoc();
+
+  if (NumBytes) { // adjust stack pointer: SPW -= numbytes
+    // If there is an SUB16ri of SPW immediately before this instruction, merge
+    // the two.
+    //NumBytes -= mergeSPUpdates(MBB, MBBI, true);
+    // If there is an ADD16ri or SUB16ri of SPW immediately after this
+    // instruction, merge the two instructions.
+    // mergeSPUpdatesDown(MBB, MBBI, &NumBytes);
+
+    if (NumBytes) {
+      MachineInstr *MI =
+        BuildMI(MBB, MBBI, DL, TII.get(MSP430::SUB16ri), MSP430::SPW)
+        .addReg(MSP430::SPW).addImm(NumBytes);
+      // The SRW implicit def is dead.
+      MI->getOperand(3).setIsDead();
+    }
+  }
+}
+
+void MSP430FrameInfo::emitEpilogue(MachineFunction &MF,
+                                   MachineBasicBlock &MBB) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
+  const MSP430RegisterInfo *RegInfo =
+    static_cast<const MSP430RegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const MSP430InstrInfo &TII =
+    *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
+
+  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  unsigned RetOpcode = MBBI->getOpcode();
+  DebugLoc DL = MBBI->getDebugLoc();
+
+  switch (RetOpcode) {
+  case MSP430::RET:
+  case MSP430::RETI: break;  // These are ok
+  default:
+    llvm_unreachable("Can only insert epilog into returning blocks");
+  }
+
+  // Get the number of bytes to allocate from the FrameInfo
+  uint64_t StackSize = MFI->getStackSize();
+  unsigned CSSize = MSP430FI->getCalleeSavedFrameSize();
+  uint64_t NumBytes = 0;
+
+  if (RegInfo->hasFP(MF)) {
+    // Calculate required stack adjustment
+    uint64_t FrameSize = StackSize - 2;
+    NumBytes = FrameSize - CSSize;
+
+    // pop FPW.
+    BuildMI(MBB, MBBI, DL, TII.get(MSP430::POP16r), MSP430::FPW);
+  } else
+    NumBytes = StackSize - CSSize;
+
+  // Skip the callee-saved pop instructions.
+  while (MBBI != MBB.begin()) {
+    MachineBasicBlock::iterator PI = prior(MBBI);
+    unsigned Opc = PI->getOpcode();
+    if (Opc != MSP430::POP16r && !PI->getDesc().isTerminator())
+      break;
+    --MBBI;
+  }
+
+  DL = MBBI->getDebugLoc();
+
+  // If there is an ADD16ri or SUB16ri of SPW immediately before this
+  // instruction, merge the two instructions.
+  //if (NumBytes || MFI->hasVarSizedObjects())
+  //  mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
+
+  if (MFI->hasVarSizedObjects()) {
+    BuildMI(MBB, MBBI, DL,
+            TII.get(MSP430::MOV16rr), MSP430::SPW).addReg(MSP430::FPW);
+    if (CSSize) {
+      MachineInstr *MI =
+        BuildMI(MBB, MBBI, DL,
+                TII.get(MSP430::SUB16ri), MSP430::SPW)
+        .addReg(MSP430::SPW).addImm(CSSize);
+      // The SRW implicit def is dead.
+      MI->getOperand(3).setIsDead();
+    }
+  } else {
+    // adjust stack pointer back: SPW += numbytes
+    if (NumBytes) {
+      MachineInstr *MI =
+        BuildMI(MBB, MBBI, DL, TII.get(MSP430::ADD16ri), MSP430::SPW)
+        .addReg(MSP430::SPW).addImm(NumBytes);
+      // The SRW implicit def is dead.
+      MI->getOperand(3).setIsDead();
+    }
+  }
+}