Rename TargetFrameInfo into TargetFrameLowering. Also, put couple of FIXMEs and fixes here and there.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123170 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 382 insertions, 0 deletions

diff --git a/lib/Target/XCore/XCoreFrameLowering.cpp b/lib/Target/XCore/XCoreFrameLowering.cpp
new file mode 100644
index 0000000000..1b91d42314
--- /dev/null
+++ b/lib/Target/XCore/XCoreFrameLowering.cpp
@@ -0,0 +1,382 @@
+//===-- XCoreFrameLowering.cpp - Frame info for XCore Target -----*- 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 XCore frame information that doesn't fit anywhere else
+// cleanly...
+//
+//===----------------------------------------------------------------------===//
+
+#include "XCore.h"
+#include "XCoreFrameLowering.h"
+#include "XCoreInstrInfo.h"
+#include "XCoreMachineFunctionInfo.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/CodeGen/RegisterScavenging.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace llvm;
+
+// helper functions. FIXME: Eliminate.
+static inline bool isImmUs(unsigned val) {
+  return val <= 11;
+}
+
+static inline bool isImmU6(unsigned val) {
+  return val < (1 << 6);
+}
+
+static inline bool isImmU16(unsigned val) {
+  return val < (1 << 16);
+}
+
+static void loadFromStack(MachineBasicBlock &MBB,
+                          MachineBasicBlock::iterator I,
+                          unsigned DstReg, int Offset, DebugLoc dl,
+                          const TargetInstrInfo &TII) {
+  assert(Offset%4 == 0 && "Misaligned stack offset");
+  Offset/=4;
+  bool isU6 = isImmU6(Offset);
+  if (!isU6 && !isImmU16(Offset))
+    report_fatal_error("loadFromStack offset too big " + Twine(Offset));
+  int Opcode = isU6 ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
+  BuildMI(MBB, I, dl, TII.get(Opcode), DstReg)
+    .addImm(Offset);
+}
+
+
+static void storeToStack(MachineBasicBlock &MBB,
+                         MachineBasicBlock::iterator I,
+                         unsigned SrcReg, int Offset, DebugLoc dl,
+                         const TargetInstrInfo &TII) {
+  assert(Offset%4 == 0 && "Misaligned stack offset");
+  Offset/=4;
+  bool isU6 = isImmU6(Offset);
+  if (!isU6 && !isImmU16(Offset))
+    report_fatal_error("storeToStack offset too big " + Twine(Offset));
+  int Opcode = isU6 ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
+  BuildMI(MBB, I, dl, TII.get(Opcode))
+    .addReg(SrcReg)
+    .addImm(Offset);
+}
+
+
+//===----------------------------------------------------------------------===//
+// XCoreFrameLowering:
+//===----------------------------------------------------------------------===//
+
+XCoreFrameLowering::XCoreFrameLowering(const XCoreSubtarget &sti)
+  : TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 4, 0),
+    STI(sti) {
+  // Do nothing
+}
+
+bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const {
+  return DisableFramePointerElim(MF) || MF.getFrameInfo()->hasVarSizedObjects();
+}
+
+void XCoreFrameLowering::emitPrologue(MachineFunction &MF) const {
+  MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MachineModuleInfo *MMI = &MF.getMMI();
+  const XCoreRegisterInfo *RegInfo =
+    static_cast<const XCoreRegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const XCoreInstrInfo &TII =
+    *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
+  XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
+  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+
+  bool FP = hasFP(MF);
+
+  // Work out frame sizes.
+  int FrameSize = MFI->getStackSize();
+  assert(FrameSize%4 == 0 && "Misaligned frame size");
+  FrameSize/=4;
+
+  bool isU6 = isImmU6(FrameSize);
+
+  if (!isU6 && !isImmU16(FrameSize)) {
+    // FIXME could emit multiple instructions.
+    report_fatal_error("emitPrologue Frame size too big: " + Twine(FrameSize));
+  }
+  bool emitFrameMoves = RegInfo->needsFrameMoves(MF);
+
+  // Do we need to allocate space on the stack?
+  if (FrameSize) {
+    bool saveLR = XFI->getUsesLR();
+    bool LRSavedOnEntry = false;
+    int Opcode;
+    if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
+      Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
+      MBB.addLiveIn(XCore::LR);
+      saveLR = false;
+      LRSavedOnEntry = true;
+    } else {
+      Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
+    }
+    BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
+
+    if (emitFrameMoves) {
+      std::vector<MachineMove> &Moves = MMI->getFrameMoves();
+
+      // Show update of SP.
+      MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
+      BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
+
+      MachineLocation SPDst(MachineLocation::VirtualFP);
+      MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
+      Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
+
+      if (LRSavedOnEntry) {
+        MachineLocation CSDst(MachineLocation::VirtualFP, 0);
+        MachineLocation CSSrc(XCore::LR);
+        Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
+      }
+    }
+    if (saveLR) {
+      int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
+      storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4, dl, TII);
+      MBB.addLiveIn(XCore::LR);
+
+      if (emitFrameMoves) {
+        MCSymbol *SaveLRLabel = MMI->getContext().CreateTempSymbol();
+        BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLRLabel);
+        MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
+        MachineLocation CSSrc(XCore::LR);
+        MMI->getFrameMoves().push_back(MachineMove(SaveLRLabel, CSDst, CSSrc));
+      }
+    }
+  }
+
+  if (FP) {
+    // Save R10 to the stack.
+    int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
+    storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4, dl, TII);
+    // R10 is live-in. It is killed at the spill.
+    MBB.addLiveIn(XCore::R10);
+    if (emitFrameMoves) {
+      MCSymbol *SaveR10Label = MMI->getContext().CreateTempSymbol();
+      BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(SaveR10Label);
+      MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
+      MachineLocation CSSrc(XCore::R10);
+      MMI->getFrameMoves().push_back(MachineMove(SaveR10Label, CSDst, CSSrc));
+    }
+    // Set the FP from the SP.
+    unsigned FramePtr = XCore::R10;
+    BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr)
+      .addImm(0);
+    if (emitFrameMoves) {
+      // Show FP is now valid.
+      MCSymbol *FrameLabel = MMI->getContext().CreateTempSymbol();
+      BuildMI(MBB, MBBI, dl, TII.get(XCore::PROLOG_LABEL)).addSym(FrameLabel);
+      MachineLocation SPDst(FramePtr);
+      MachineLocation SPSrc(MachineLocation::VirtualFP);
+      MMI->getFrameMoves().push_back(MachineMove(FrameLabel, SPDst, SPSrc));
+    }
+  }
+
+  if (emitFrameMoves) {
+    // Frame moves for callee saved.
+    std::vector<MachineMove> &Moves = MMI->getFrameMoves();
+    std::vector<std::pair<MCSymbol*, CalleeSavedInfo> >&SpillLabels =
+        XFI->getSpillLabels();
+    for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
+      MCSymbol *SpillLabel = SpillLabels[I].first;
+      CalleeSavedInfo &CSI = SpillLabels[I].second;
+      int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
+      unsigned Reg = CSI.getReg();
+      MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
+      MachineLocation CSSrc(Reg);
+      Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
+    }
+  }
+}
+
+void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
+                                     MachineBasicBlock &MBB) const {
+  MachineFrameInfo *MFI            = MF.getFrameInfo();
+  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  const XCoreInstrInfo &TII =
+    *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
+  DebugLoc dl = MBBI->getDebugLoc();
+
+  bool FP = hasFP(MF);
+  if (FP) {
+    // Restore the stack pointer.
+    unsigned FramePtr = XCore::R10;
+    BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
+      .addReg(FramePtr);
+  }
+
+  // Work out frame sizes.
+  int FrameSize = MFI->getStackSize();
+
+  assert(FrameSize%4 == 0 && "Misaligned frame size");
+
+  FrameSize/=4;
+
+  bool isU6 = isImmU6(FrameSize);
+
+  if (!isU6 && !isImmU16(FrameSize)) {
+    // FIXME could emit multiple instructions.
+    report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
+  }
+
+  if (FrameSize) {
+    XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
+
+    if (FP) {
+      // Restore R10
+      int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
+      FPSpillOffset += FrameSize*4;
+      loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
+    }
+    bool restoreLR = XFI->getUsesLR();
+    if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
+      int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
+      LRSpillOffset += FrameSize*4;
+      loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
+      restoreLR = false;
+    }
+    if (restoreLR) {
+      // Fold prologue into return instruction
+      assert(MBBI->getOpcode() == XCore::RETSP_u6
+        || MBBI->getOpcode() == XCore::RETSP_lu6);
+      int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
+      BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
+      MBB.erase(MBBI);
+    } else {
+      int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
+      BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
+    }
+  }
+}
+
+void XCoreFrameLowering::getInitialFrameState(std::vector<MachineMove> &Moves)
+                                                                        const {
+  // Initial state of the frame pointer is SP.
+  MachineLocation Dst(MachineLocation::VirtualFP);
+  MachineLocation Src(XCore::SP, 0);
+  Moves.push_back(MachineMove(0, Dst, Src));
+}
+
+bool XCoreFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
+                                               MachineBasicBlock::iterator MI,
+                                        const std::vector<CalleeSavedInfo> &CSI,
+                                          const TargetRegisterInfo *TRI) const {
+  if (CSI.empty())
+    return true;
+
+  MachineFunction *MF = MBB.getParent();
+  const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
+
+  XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
+  bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);
+
+  DebugLoc DL;
+  if (MI != MBB.end()) DL = MI->getDebugLoc();
+
+  for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
+                                                    it != CSI.end(); ++it) {
+    // Add the callee-saved register as live-in. It's killed at the spill.
+    MBB.addLiveIn(it->getReg());
+
+    unsigned Reg = it->getReg();
+    const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+    TII.storeRegToStackSlot(MBB, MI, Reg, true,
+                            it->getFrameIdx(), RC, TRI);
+    if (emitFrameMoves) {
+      MCSymbol *SaveLabel = MF->getContext().CreateTempSymbol();
+      BuildMI(MBB, MI, DL, TII.get(XCore::PROLOG_LABEL)).addSym(SaveLabel);
+      XFI->getSpillLabels().push_back(std::make_pair(SaveLabel, *it));
+    }
+  }
+  return true;
+}
+
+bool XCoreFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
+                                                 MachineBasicBlock::iterator MI,
+                                        const std::vector<CalleeSavedInfo> &CSI,
+                                            const TargetRegisterInfo *TRI) const{
+  MachineFunction *MF = MBB.getParent();
+  const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
+
+  bool AtStart = MI == MBB.begin();
+  MachineBasicBlock::iterator BeforeI = MI;
+  if (!AtStart)
+    --BeforeI;
+  for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
+                                                    it != CSI.end(); ++it) {
+    unsigned Reg = it->getReg();
+    const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+    TII.loadRegFromStackSlot(MBB, MI, it->getReg(), it->getFrameIdx(),
+                             RC, TRI);
+    assert(MI != MBB.begin() &&
+           "loadRegFromStackSlot didn't insert any code!");
+    // Insert in reverse order.  loadRegFromStackSlot can insert multiple
+    // instructions.
+    if (AtStart)
+      MI = MBB.begin();
+    else {
+      MI = BeforeI;
+      ++MI;
+    }
+  }
+  return true;
+}
+
+void
+XCoreFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+                                                     RegScavenger *RS) const {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
+  bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
+  const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
+  XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
+  if (LRUsed) {
+    MF.getRegInfo().setPhysRegUnused(XCore::LR);
+
+    bool isVarArg = MF.getFunction()->isVarArg();
+    int FrameIdx;
+    if (! isVarArg) {
+      // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
+      FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0, true);
+    } else {
+      FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment(),
+                                        false);
+    }
+    XFI->setUsesLR(FrameIdx);
+    XFI->setLRSpillSlot(FrameIdx);
+  }
+  if (RegInfo->requiresRegisterScavenging(MF)) {
+    // Reserve a slot close to SP or frame pointer.
+    RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
+                                                       RC->getAlignment(),
+                                                       false));
+  }
+  if (hasFP(MF)) {
+    // A callee save register is used to hold the FP.
+    // This needs saving / restoring in the epilogue / prologue.
+    XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
+                                               RC->getAlignment(),
+                                               false));
+  }
+}
+
+void XCoreFrameLowering::
+processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
+
+}