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

1 files changed, 376 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMFrameInfo.cpp b/lib/Target/ARM/ARMFrameInfo.cpp
new file mode 100644
index 0000000000..499111af06
--- /dev/null
+++ b/lib/Target/ARM/ARMFrameInfo.cpp
@@ -0,0 +1,376 @@
+//=======- ARMFrameInfo.cpp - ARM 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 ARM implementation of TargetFrameInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ARMFrameInfo.h"
+#include "ARMBaseInstrInfo.h"
+#include "ARMMachineFunctionInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+
+using namespace llvm;
+
+/// Move iterator past the next bunch of callee save load / store ops for
+/// the particular spill area (1: integer area 1, 2: integer area 2,
+/// 3: fp area, 0: don't care).
+static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
+                                   MachineBasicBlock::iterator &MBBI,
+                                   int Opc1, int Opc2, unsigned Area,
+                                   const ARMSubtarget &STI) {
+  while (MBBI != MBB.end() &&
+         ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
+         MBBI->getOperand(1).isFI()) {
+    if (Area != 0) {
+      bool Done = false;
+      unsigned Category = 0;
+      switch (MBBI->getOperand(0).getReg()) {
+      case ARM::R4:  case ARM::R5:  case ARM::R6: case ARM::R7:
+      case ARM::LR:
+        Category = 1;
+        break;
+      case ARM::R8:  case ARM::R9:  case ARM::R10: case ARM::R11:
+        Category = STI.isTargetDarwin() ? 2 : 1;
+        break;
+      case ARM::D8:  case ARM::D9:  case ARM::D10: case ARM::D11:
+      case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
+        Category = 3;
+        break;
+      default:
+        Done = true;
+        break;
+      }
+      if (Done || Category != Area)
+        break;
+    }
+
+    ++MBBI;
+  }
+}
+
+static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
+  for (unsigned i = 0; CSRegs[i]; ++i)
+    if (Reg == CSRegs[i])
+      return true;
+  return false;
+}
+
+static bool isCSRestore(MachineInstr *MI,
+                        const ARMBaseInstrInfo &TII,
+                        const unsigned *CSRegs) {
+  return ((MI->getOpcode() == (int)ARM::VLDRD ||
+           MI->getOpcode() == (int)ARM::LDRi12 ||
+           MI->getOpcode() == (int)ARM::t2LDRi12) &&
+          MI->getOperand(1).isFI() &&
+          isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
+}
+
+static void
+emitSPUpdate(bool isARM,
+             MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
+             DebugLoc dl, const ARMBaseInstrInfo &TII,
+             int NumBytes,
+             ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
+  if (isARM)
+    emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
+                            Pred, PredReg, TII);
+  else
+    emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
+                           Pred, PredReg, TII);
+}
+
+void ARMFrameInfo::emitPrologue(MachineFunction &MF) const {
+  MachineBasicBlock &MBB = MF.front();
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+  MachineFrameInfo  *MFI = MF.getFrameInfo();
+  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+  const ARMBaseRegisterInfo *RegInfo =
+    static_cast<const ARMBaseRegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const ARMBaseInstrInfo &TII =
+    *static_cast<const ARMBaseInstrInfo*>(MF.getTarget().getInstrInfo());
+  assert(!AFI->isThumb1OnlyFunction() &&
+         "This emitPrologue does not support Thumb1!");
+  bool isARM = !AFI->isThumbFunction();
+  unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
+  unsigned NumBytes = MFI->getStackSize();
+  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
+  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+  unsigned FramePtr = RegInfo->getFrameRegister(MF);
+
+  // Determine the sizes of each callee-save spill areas and record which frame
+  // belongs to which callee-save spill areas.
+  unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
+  int FramePtrSpillFI = 0;
+
+  // Allocate the vararg register save area. This is not counted in NumBytes.
+  if (VARegSaveSize)
+    emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
+
+  if (!AFI->hasStackFrame()) {
+    if (NumBytes != 0)
+      emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
+    return;
+  }
+
+  for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
+    unsigned Reg = CSI[i].getReg();
+    int FI = CSI[i].getFrameIdx();
+    switch (Reg) {
+    case ARM::R4:
+    case ARM::R5:
+    case ARM::R6:
+    case ARM::R7:
+    case ARM::LR:
+      if (Reg == FramePtr)
+        FramePtrSpillFI = FI;
+      AFI->addGPRCalleeSavedArea1Frame(FI);
+      GPRCS1Size += 4;
+      break;
+    case ARM::R8:
+    case ARM::R9:
+    case ARM::R10:
+    case ARM::R11:
+      if (Reg == FramePtr)
+        FramePtrSpillFI = FI;
+      if (STI.isTargetDarwin()) {
+        AFI->addGPRCalleeSavedArea2Frame(FI);
+        GPRCS2Size += 4;
+      } else {
+        AFI->addGPRCalleeSavedArea1Frame(FI);
+        GPRCS1Size += 4;
+      }
+      break;
+    default:
+      AFI->addDPRCalleeSavedAreaFrame(FI);
+      DPRCSSize += 8;
+    }
+  }
+
+  // Build the new SUBri to adjust SP for integer callee-save spill area 1.
+  emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
+  movePastCSLoadStoreOps(MBB, MBBI, ARM::STRi12, ARM::t2STRi12, 1, STI);
+
+  // Set FP to point to the stack slot that contains the previous FP.
+  // For Darwin, FP is R7, which has now been stored in spill area 1.
+  // Otherwise, if this is not Darwin, all the callee-saved registers go
+  // into spill area 1, including the FP in R11.  In either case, it is
+  // now safe to emit this assignment.
+  bool HasFP = RegInfo->hasFP(MF);
+  if (HasFP) {
+    unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
+    MachineInstrBuilder MIB =
+      BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
+      .addFrameIndex(FramePtrSpillFI).addImm(0);
+    AddDefaultCC(AddDefaultPred(MIB));
+  }
+
+  // Build the new SUBri to adjust SP for integer callee-save spill area 2.
+  emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
+
+  // Build the new SUBri to adjust SP for FP callee-save spill area.
+  movePastCSLoadStoreOps(MBB, MBBI, ARM::STRi12, ARM::t2STRi12, 2, STI);
+  emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
+
+  // Determine starting offsets of spill areas.
+  unsigned DPRCSOffset  = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
+  unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
+  unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
+  if (HasFP)
+    AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) +
+                                NumBytes);
+  AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
+  AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
+  AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
+
+  movePastCSLoadStoreOps(MBB, MBBI, ARM::VSTRD, 0, 3, STI);
+  NumBytes = DPRCSOffset;
+  if (NumBytes) {
+    // Adjust SP after all the callee-save spills.
+    emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
+    if (HasFP)
+      AFI->setShouldRestoreSPFromFP(true);
+  }
+
+  if (STI.isTargetELF() && RegInfo->hasFP(MF)) {
+    MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
+                             AFI->getFramePtrSpillOffset());
+    AFI->setShouldRestoreSPFromFP(true);
+  }
+
+  AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
+  AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
+  AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
+
+  // If we need dynamic stack realignment, do it here. Be paranoid and make
+  // sure if we also have VLAs, we have a base pointer for frame access.
+  if (RegInfo->needsStackRealignment(MF)) {
+    unsigned MaxAlign = MFI->getMaxAlignment();
+    assert (!AFI->isThumb1OnlyFunction());
+    if (!AFI->isThumbFunction()) {
+      // Emit bic sp, sp, MaxAlign
+      AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
+                                          TII.get(ARM::BICri), ARM::SP)
+                                  .addReg(ARM::SP, RegState::Kill)
+                                  .addImm(MaxAlign-1)));
+    } else {
+      // We cannot use sp as source/dest register here, thus we're emitting the
+      // following sequence:
+      // mov r4, sp
+      // bic r4, r4, MaxAlign
+      // mov sp, r4
+      // FIXME: It will be better just to find spare register here.
+      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2tgpr), ARM::R4)
+        .addReg(ARM::SP, RegState::Kill);
+      AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
+                                          TII.get(ARM::t2BICri), ARM::R4)
+                                  .addReg(ARM::R4, RegState::Kill)
+                                  .addImm(MaxAlign-1)));
+      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
+        .addReg(ARM::R4, RegState::Kill);
+    }
+
+    AFI->setShouldRestoreSPFromFP(true);
+  }
+
+  // If we need a base pointer, set it up here. It's whatever the value
+  // of the stack pointer is at this point. Any variable size objects
+  // will be allocated after this, so we can still use the base pointer
+  // to reference locals.
+  if (RegInfo->hasBasePointer(MF)) {
+    if (isARM)
+      BuildMI(MBB, MBBI, dl,
+              TII.get(ARM::MOVr), RegInfo->getBaseRegister())
+        .addReg(ARM::SP)
+        .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
+    else
+      BuildMI(MBB, MBBI, dl,
+              TII.get(ARM::tMOVgpr2gpr), RegInfo->getBaseRegister())
+        .addReg(ARM::SP);
+  }
+
+  // If the frame has variable sized objects then the epilogue must restore
+  // the sp from fp.
+  if (!AFI->shouldRestoreSPFromFP() && MFI->hasVarSizedObjects())
+    AFI->setShouldRestoreSPFromFP(true);
+}
+
+void ARMFrameInfo::emitEpilogue(MachineFunction &MF,
+                                MachineBasicBlock &MBB) const {
+  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  assert(MBBI->getDesc().isReturn() &&
+         "Can only insert epilog into returning blocks");
+  unsigned RetOpcode = MBBI->getOpcode();
+  DebugLoc dl = MBBI->getDebugLoc();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+  const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
+  const ARMBaseInstrInfo &TII =
+    *static_cast<const ARMBaseInstrInfo*>(MF.getTarget().getInstrInfo());
+  assert(!AFI->isThumb1OnlyFunction() &&
+         "This emitEpilogue does not support Thumb1!");
+  bool isARM = !AFI->isThumbFunction();
+
+  unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
+  int NumBytes = (int)MFI->getStackSize();
+  unsigned FramePtr = RegInfo->getFrameRegister(MF);
+
+  if (!AFI->hasStackFrame()) {
+    if (NumBytes != 0)
+      emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
+  } else {
+    // Unwind MBBI to point to first LDR / VLDRD.
+    const unsigned *CSRegs = RegInfo->getCalleeSavedRegs();
+    if (MBBI != MBB.begin()) {
+      do
+        --MBBI;
+      while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
+      if (!isCSRestore(MBBI, TII, CSRegs))
+        ++MBBI;
+    }
+
+    // Move SP to start of FP callee save spill area.
+    NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
+                 AFI->getGPRCalleeSavedArea2Size() +
+                 AFI->getDPRCalleeSavedAreaSize());
+
+    // Reset SP based on frame pointer only if the stack frame extends beyond
+    // frame pointer stack slot or target is ELF and the function has FP.
+    if (AFI->shouldRestoreSPFromFP()) {
+      NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
+      if (NumBytes) {
+        if (isARM)
+          emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
+                                  ARMCC::AL, 0, TII);
+        else
+          emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
+                                 ARMCC::AL, 0, TII);
+      } else {
+        // Thumb2 or ARM.
+        if (isARM)
+          BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
+            .addReg(FramePtr).addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
+        else
+          BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
+            .addReg(FramePtr);
+      }
+    } else if (NumBytes)
+      emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
+
+    // Move SP to start of integer callee save spill area 2.
+    movePastCSLoadStoreOps(MBB, MBBI, ARM::VLDRD, 0, 3, STI);
+    emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
+
+    // Move SP to start of integer callee save spill area 1.
+    movePastCSLoadStoreOps(MBB, MBBI, ARM::LDRi12, ARM::t2LDRi12, 2, STI);
+    emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
+
+    // Move SP to SP upon entry to the function.
+    movePastCSLoadStoreOps(MBB, MBBI, ARM::LDRi12, ARM::t2LDRi12, 1, STI);
+    emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
+  }
+
+  if (RetOpcode == ARM::TCRETURNdi || RetOpcode == ARM::TCRETURNdiND ||
+      RetOpcode == ARM::TCRETURNri || RetOpcode == ARM::TCRETURNriND) {
+    // Tail call return: adjust the stack pointer and jump to callee.
+    MBBI = prior(MBB.end());
+    MachineOperand &JumpTarget = MBBI->getOperand(0);
+
+    // Jump to label or value in register.
+    if (RetOpcode == ARM::TCRETURNdi) {
+      BuildMI(MBB, MBBI, dl,
+            TII.get(STI.isThumb() ? ARM::TAILJMPdt : ARM::TAILJMPd)).
+        addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
+                         JumpTarget.getTargetFlags());
+    } else if (RetOpcode == ARM::TCRETURNdiND) {
+      BuildMI(MBB, MBBI, dl,
+            TII.get(STI.isThumb() ? ARM::TAILJMPdNDt : ARM::TAILJMPdND)).
+        addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
+                         JumpTarget.getTargetFlags());
+    } else if (RetOpcode == ARM::TCRETURNri) {
+      BuildMI(MBB, MBBI, dl, TII.get(ARM::TAILJMPr)).
+        addReg(JumpTarget.getReg(), RegState::Kill);
+    } else if (RetOpcode == ARM::TCRETURNriND) {
+      BuildMI(MBB, MBBI, dl, TII.get(ARM::TAILJMPrND)).
+        addReg(JumpTarget.getReg(), RegState::Kill);
+    }
+
+    MachineInstr *NewMI = prior(MBBI);
+    for (unsigned i = 1, e = MBBI->getNumOperands(); i != e; ++i)
+      NewMI->addOperand(MBBI->getOperand(i));
+
+    // Delete the pseudo instruction TCRETURN.
+    MBB.erase(MBBI);
+  }
+
+  if (VARegSaveSize)
+    emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
+}