--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Target/Sparc/DelaySlotFiller.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,505 @@
+//===-- DelaySlotFiller.cpp - SPARC delay slot filler ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a simple local pass that attempts to fill delay slots with useful
+// instructions. If no instructions can be moved into the delay slot, then a
+// NOP is placed.
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "delay-slot-filler"
+#include "Sparc.h"
+#include "SparcSubtarget.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+
+using namespace llvm;
+
+STATISTIC(FilledSlots, "Number of delay slots filled");
+
+static cl::opt<bool> DisableDelaySlotFiller(
+  "disable-sparc-delay-filler",
+  cl::init(false),
+  cl::desc("Disable the Sparc delay slot filler."),
+  cl::Hidden);
+
+namespace {
+  struct Filler : public MachineFunctionPass {
+    /// Target machine description which we query for reg. names, data
+    /// layout, etc.
+    ///
+    TargetMachine &TM;
+    const SparcSubtarget *Subtarget;
+
+    static char ID;
+    Filler(TargetMachine &tm)
+      : MachineFunctionPass(ID), TM(tm),
+        Subtarget(&TM.getSubtarget<SparcSubtarget>()) {
+    }
+
+    virtual const char *getPassName() const {
+      return "SPARC Delay Slot Filler";
+    }
+
+    bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
+    bool runOnMachineFunction(MachineFunction &F) {
+      bool Changed = false;
+      for (MachineFunction::iterator FI = F.begin(), FE = F.end();
+           FI != FE; ++FI)
+        Changed |= runOnMachineBasicBlock(*FI);
+      return Changed;
+    }
+
+    bool isDelayFiller(MachineBasicBlock &MBB,
+                       MachineBasicBlock::iterator candidate);
+
+    void insertCallDefsUses(MachineBasicBlock::iterator MI,
+                            SmallSet<unsigned, 32>& RegDefs,
+                            SmallSet<unsigned, 32>& RegUses);
+
+    void insertDefsUses(MachineBasicBlock::iterator MI,
+                        SmallSet<unsigned, 32>& RegDefs,
+                        SmallSet<unsigned, 32>& RegUses);
+
+    bool IsRegInSet(SmallSet<unsigned, 32>& RegSet,
+                    unsigned Reg);
+
+    bool delayHasHazard(MachineBasicBlock::iterator candidate,
+                        bool &sawLoad, bool &sawStore,
+                        SmallSet<unsigned, 32> &RegDefs,
+                        SmallSet<unsigned, 32> &RegUses);
+
+    MachineBasicBlock::iterator
+    findDelayInstr(MachineBasicBlock &MBB, MachineBasicBlock::iterator slot);
+
+    bool needsUnimp(MachineBasicBlock::iterator I, unsigned &StructSize);
+
+    bool tryCombineRestoreWithPrevInst(MachineBasicBlock &MBB,
+                                       MachineBasicBlock::iterator MBBI);
+
+  };
+  char Filler::ID = 0;
+} // end of anonymous namespace
+
+/// createSparcDelaySlotFillerPass - Returns a pass that fills in delay
+/// slots in Sparc MachineFunctions
+///
+FunctionPass *llvm::createSparcDelaySlotFillerPass(TargetMachine &tm) {
+  return new Filler(tm);
+}
+
+
+/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
+/// We assume there is only one delay slot per delayed instruction.
+///
+bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
+  bool Changed = false;
+
+  const TargetInstrInfo *TII = TM.getInstrInfo();
+
+  for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ) {
+    MachineBasicBlock::iterator MI = I;
+    ++I;
+
+    // If MI is restore, try combining it with previous inst.
+    if (!DisableDelaySlotFiller &&
+        (MI->getOpcode() == SP::RESTORErr
+         || MI->getOpcode() == SP::RESTOREri)) {
+      Changed |= tryCombineRestoreWithPrevInst(MBB, MI);
+      continue;
+    }
+
+    if (!Subtarget->isV9() &&
+        (MI->getOpcode() == SP::FCMPS || MI->getOpcode() == SP::FCMPD
+         || MI->getOpcode() == SP::FCMPQ)) {
+      BuildMI(MBB, I, MI->getDebugLoc(), TII->get(SP::NOP));
+      Changed = true;
+      continue;
+    }
+
+    // If MI has no delay slot, skip.
+    if (!MI->hasDelaySlot())
+      continue;
+
+    MachineBasicBlock::iterator D = MBB.end();
+
+    if (!DisableDelaySlotFiller)
+      D = findDelayInstr(MBB, MI);
+
+    ++FilledSlots;
+    Changed = true;
+
+    if (D == MBB.end())
+      BuildMI(MBB, I, MI->getDebugLoc(), TII->get(SP::NOP));
+    else
+      MBB.splice(I, &MBB, D);
+
+    unsigned structSize = 0;
+    if (needsUnimp(MI, structSize)) {
+      MachineBasicBlock::iterator J = MI;
+      ++J; // skip the delay filler.
+      assert (J != MBB.end() && "MI needs a delay instruction.");
+      BuildMI(MBB, ++J, MI->getDebugLoc(),
+              TII->get(SP::UNIMP)).addImm(structSize);
+    }
+  }
+  return Changed;
+}
+
+MachineBasicBlock::iterator
+Filler::findDelayInstr(MachineBasicBlock &MBB,
+                       MachineBasicBlock::iterator slot)
+{
+  SmallSet<unsigned, 32> RegDefs;
+  SmallSet<unsigned, 32> RegUses;
+  bool sawLoad = false;
+  bool sawStore = false;
+
+  if (slot == MBB.begin())
+    return MBB.end();
+
+  if (slot->getOpcode() == SP::RET || slot->getOpcode() == SP::TLS_CALL)
+    return MBB.end();
+
+  if (slot->getOpcode() == SP::RETL) {
+    MachineBasicBlock::iterator J = slot;
+    --J;
+
+    if (J->getOpcode() == SP::RESTORErr
+        || J->getOpcode() == SP::RESTOREri) {
+      // change retl to ret.
+      slot->setDesc(TM.getInstrInfo()->get(SP::RET));
+      return J;
+    }
+  }
+
+  // Call's delay filler can def some of call's uses.
+  if (slot->isCall())
+    insertCallDefsUses(slot, RegDefs, RegUses);
+  else
+    insertDefsUses(slot, RegDefs, RegUses);
+
+  bool done = false;
+
+  MachineBasicBlock::iterator I = slot;
+
+  while (!done) {
+    done = (I == MBB.begin());
+
+    if (!done)
+      --I;
+
+    // skip debug value
+    if (I->isDebugValue())
+      continue;
+
+
+    if (I->hasUnmodeledSideEffects()
+        || I->isInlineAsm()
+        || I->isLabel()
+        || I->hasDelaySlot()
+        || isDelayFiller(MBB, I))
+      break;
+
+    if (delayHasHazard(I, sawLoad, sawStore, RegDefs, RegUses)) {
+      insertDefsUses(I, RegDefs, RegUses);
+      continue;
+    }
+
+    return I;
+  }
+  return MBB.end();
+}
+
+bool Filler::delayHasHazard(MachineBasicBlock::iterator candidate,
+                            bool &sawLoad,
+                            bool &sawStore,
+                            SmallSet<unsigned, 32> &RegDefs,
+                            SmallSet<unsigned, 32> &RegUses)
+{
+
+  if (candidate->isImplicitDef() || candidate->isKill())
+    return true;
+
+  if (candidate->mayLoad()) {
+    sawLoad = true;
+    if (sawStore)
+      return true;
+  }
+
+  if (candidate->mayStore()) {
+    if (sawStore)
+      return true;
+    sawStore = true;
+    if (sawLoad)
+      return true;
+  }
+
+  for (unsigned i = 0, e = candidate->getNumOperands(); i!= e; ++i) {
+    const MachineOperand &MO = candidate->getOperand(i);
+    if (!MO.isReg())
+      continue; // skip
+
+    unsigned Reg = MO.getReg();
+
+    if (MO.isDef()) {
+      // check whether Reg is defined or used before delay slot.
+      if (IsRegInSet(RegDefs, Reg) || IsRegInSet(RegUses, Reg))
+        return true;
+    }
+    if (MO.isUse()) {
+      // check whether Reg is defined before delay slot.
+      if (IsRegInSet(RegDefs, Reg))
+        return true;
+    }
+  }
+  return false;
+}
+
+
+void Filler::insertCallDefsUses(MachineBasicBlock::iterator MI,
+                                SmallSet<unsigned, 32>& RegDefs,
+                                SmallSet<unsigned, 32>& RegUses)
+{
+  // Call defines o7, which is visible to the instruction in delay slot.
+  RegDefs.insert(SP::O7);
+
+  switch(MI->getOpcode()) {
+  default: llvm_unreachable("Unknown opcode.");
+  case SP::CALL: break;
+  case SP::JMPLrr:
+  case SP::JMPLri:
+    assert(MI->getNumOperands() >= 2);
+    const MachineOperand &Reg = MI->getOperand(0);
+    assert(Reg.isReg() && "JMPL first operand is not a register.");
+    assert(Reg.isUse() && "JMPL first operand is not a use.");
+    RegUses.insert(Reg.getReg());
+
+    const MachineOperand &RegOrImm = MI->getOperand(1);
+    if (RegOrImm.isImm())
+        break;
+    assert(RegOrImm.isReg() && "JMPLrr second operand is not a register.");
+    assert(RegOrImm.isUse() && "JMPLrr second operand is not a use.");
+    RegUses.insert(RegOrImm.getReg());
+    break;
+  }
+}
+
+// Insert Defs and Uses of MI into the sets RegDefs and RegUses.
+void Filler::insertDefsUses(MachineBasicBlock::iterator MI,
+                            SmallSet<unsigned, 32>& RegDefs,
+                            SmallSet<unsigned, 32>& RegUses)
+{
+  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = MI->getOperand(i);
+    if (!MO.isReg())
+      continue;
+
+    unsigned Reg = MO.getReg();
+    if (Reg == 0)
+      continue;
+    if (MO.isDef())
+      RegDefs.insert(Reg);
+    if (MO.isUse()) {
+      // Implicit register uses of retl are return values and
+      // retl does not use them.
+      if (MO.isImplicit() && MI->getOpcode() == SP::RETL)
+        continue;
+      RegUses.insert(Reg);
+    }
+  }
+}
+
+// returns true if the Reg or its alias is in the RegSet.
+bool Filler::IsRegInSet(SmallSet<unsigned, 32>& RegSet, unsigned Reg)
+{
+  // Check Reg and all aliased Registers.
+  for (MCRegAliasIterator AI(Reg, TM.getRegisterInfo(), true);
+       AI.isValid(); ++AI)
+    if (RegSet.count(*AI))
+      return true;
+  return false;
+}
+
+// return true if the candidate is a delay filler.
+bool Filler::isDelayFiller(MachineBasicBlock &MBB,
+                           MachineBasicBlock::iterator candidate)
+{
+  if (candidate == MBB.begin())
+    return false;
+  if (candidate->getOpcode() == SP::UNIMP)
+    return true;
+  --candidate;
+  return candidate->hasDelaySlot();
+}
+
+bool Filler::needsUnimp(MachineBasicBlock::iterator I, unsigned &StructSize)
+{
+  if (!I->isCall())
+    return false;
+
+  unsigned structSizeOpNum = 0;
+  switch (I->getOpcode()) {
+  default: llvm_unreachable("Unknown call opcode.");
+  case SP::CALL: structSizeOpNum = 1; break;
+  case SP::JMPLrr:
+  case SP::JMPLri: structSizeOpNum = 2; break;
+  case SP::TLS_CALL: return false;
+  }
+
+  const MachineOperand &MO = I->getOperand(structSizeOpNum);
+  if (!MO.isImm())
+    return false;
+  StructSize = MO.getImm();
+  return true;
+}
+
+static bool combineRestoreADD(MachineBasicBlock::iterator RestoreMI,
+                              MachineBasicBlock::iterator AddMI,
+                              const TargetInstrInfo *TII)
+{
+  // Before:  add  <op0>, <op1>, %i[0-7]
+  //          restore %g0, %g0, %i[0-7]
+  //
+  // After :  restore <op0>, <op1>, %o[0-7]
+
+  unsigned reg = AddMI->getOperand(0).getReg();
+  if (reg < SP::I0 || reg > SP::I7)
+    return false;
+
+  // Erase RESTORE.
+  RestoreMI->eraseFromParent();
+
+  // Change ADD to RESTORE.
+  AddMI->setDesc(TII->get((AddMI->getOpcode() == SP::ADDrr)
+                          ? SP::RESTORErr
+                          : SP::RESTOREri));
+
+  // Map the destination register.
+  AddMI->getOperand(0).setReg(reg - SP::I0 + SP::O0);
+
+  return true;
+}
+
+static bool combineRestoreOR(MachineBasicBlock::iterator RestoreMI,
+                             MachineBasicBlock::iterator OrMI,
+                             const TargetInstrInfo *TII)
+{
+  // Before:  or  <op0>, <op1>, %i[0-7]
+  //          restore %g0, %g0, %i[0-7]
+  //    and <op0> or <op1> is zero,
+  //
+  // After :  restore <op0>, <op1>, %o[0-7]
+
+  unsigned reg = OrMI->getOperand(0).getReg();
+  if (reg < SP::I0 || reg > SP::I7)
+    return false;
+
+  // check whether it is a copy.
+  if (OrMI->getOpcode() == SP::ORrr
+      && OrMI->getOperand(1).getReg() != SP::G0
+      && OrMI->getOperand(2).getReg() != SP::G0)
+    return false;
+
+  if (OrMI->getOpcode() == SP::ORri
+      && OrMI->getOperand(1).getReg() != SP::G0
+      && (!OrMI->getOperand(2).isImm() || OrMI->getOperand(2).getImm() != 0))
+    return false;
+
+  // Erase RESTORE.
+  RestoreMI->eraseFromParent();
+
+  // Change OR to RESTORE.
+  OrMI->setDesc(TII->get((OrMI->getOpcode() == SP::ORrr)
+                         ? SP::RESTORErr
+                         : SP::RESTOREri));
+
+  // Map the destination register.
+  OrMI->getOperand(0).setReg(reg - SP::I0 + SP::O0);
+
+  return true;
+}
+
+static bool combineRestoreSETHIi(MachineBasicBlock::iterator RestoreMI,
+                                 MachineBasicBlock::iterator SetHiMI,
+                                 const TargetInstrInfo *TII)
+{
+  // Before:  sethi imm3, %i[0-7]
+  //          restore %g0, %g0, %g0
+  //
+  // After :  restore %g0, (imm3<<10), %o[0-7]
+
+  unsigned reg = SetHiMI->getOperand(0).getReg();
+  if (reg < SP::I0 || reg > SP::I7)
+    return false;
+
+  if (!SetHiMI->getOperand(1).isImm())
+    return false;
+
+  int64_t imm = SetHiMI->getOperand(1).getImm();
+
+  // Is it a 3 bit immediate?
+  if (!isInt<3>(imm))
+    return false;
+
+  // Make it a 13 bit immediate.
+  imm = (imm << 10) & 0x1FFF;
+
+  assert(RestoreMI->getOpcode() == SP::RESTORErr);
+
+  RestoreMI->setDesc(TII->get(SP::RESTOREri));
+
+  RestoreMI->getOperand(0).setReg(reg - SP::I0 + SP::O0);
+  RestoreMI->getOperand(1).setReg(SP::G0);
+  RestoreMI->getOperand(2).ChangeToImmediate(imm);
+
+
+  // Erase the original SETHI.
+  SetHiMI->eraseFromParent();
+
+  return true;
+}
+
+bool Filler::tryCombineRestoreWithPrevInst(MachineBasicBlock &MBB,
+                                        MachineBasicBlock::iterator MBBI)
+{
+  // No previous instruction.
+  if (MBBI == MBB.begin())
+    return false;
+
+  // assert that MBBI is a "restore %g0, %g0, %g0".
+  assert(MBBI->getOpcode() == SP::RESTORErr
+         && MBBI->getOperand(0).getReg() == SP::G0
+         && MBBI->getOperand(1).getReg() == SP::G0
+         && MBBI->getOperand(2).getReg() == SP::G0);
+
+  MachineBasicBlock::iterator PrevInst = MBBI; --PrevInst;
+
+  // It cannot combine with a delay filler.
+  if (isDelayFiller(MBB, PrevInst))
+    return false;
+
+  const TargetInstrInfo *TII = TM.getInstrInfo();
+
+  switch (PrevInst->getOpcode()) {
+  default: break;
+  case SP::ADDrr:
+  case SP::ADDri: return combineRestoreADD(MBBI, PrevInst, TII); break;
+  case SP::ORrr:
+  case SP::ORri:  return combineRestoreOR(MBBI, PrevInst, TII); break;
+  case SP::SETHIi: return combineRestoreSETHIi(MBBI, PrevInst, TII); break;
+  }
+  // It cannot combine with the previous instruction.
+  return false;
+}