MachineInstrBundle.cpp revision bca15f9c8059ccb9244853f86593c35ac35c8801 
1//===-- lib/CodeGen/MachineInstrBundle.cpp --------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/CodeGen/MachineInstrBundle.h"
11#include "llvm/CodeGen/MachineInstrBuilder.h"
12#include "llvm/CodeGen/Passes.h"
13#include "llvm/CodeGen/MachineFunctionPass.h"
14#include "llvm/Target/TargetInstrInfo.h"
15#include "llvm/Target/TargetMachine.h"
16#include "llvm/Target/TargetRegisterInfo.h"
17#include "llvm/ADT/SmallSet.h"
18#include "llvm/ADT/SmallVector.h"
19using namespace llvm;
20
21namespace {
22  class UnpackMachineBundles : public MachineFunctionPass {
23  public:
24    static char ID; // Pass identification
25    UnpackMachineBundles() : MachineFunctionPass(ID) {
26      initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
27    }
28
29    virtual bool runOnMachineFunction(MachineFunction &MF);
30  };
31} // end anonymous namespace
32
33char UnpackMachineBundles::ID = 0;
34INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundle",
35                "Unpack machine instruction bundles", false, false)
36
37FunctionPass *llvm::createUnpackMachineBundlesPass() {
38  return new UnpackMachineBundles();
39}
40
41bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
42  bool Changed = false;
43  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
44    MachineBasicBlock *MBB = &*I;
45
46    for (MachineBasicBlock::instr_iterator MII = MBB->instr_begin(),
47           MIE = MBB->instr_end(); MII != MIE; ) {
48      MachineInstr *MI = &*MII;
49
50      // Remove BUNDLE instruction and the InsideBundle flags from bundled
51      // instructions.
52      if (MI->isBundle()) {
53        while (++MII != MIE && MII->isInsideBundle()) {
54          MII->setIsInsideBundle(false);
55          for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
56            MachineOperand &MO = MII->getOperand(i);
57            if (MO.isReg() && MO.isInternalRead())
58              MO.setIsInternalRead(false);
59          }
60        }
61        MI->eraseFromParent();
62
63        Changed = true;
64        continue;
65      }
66
67      ++MII;
68    }
69  }
70
71  return Changed;
72}
73
74/// finalizeBundle - Finalize a machine instruction bundle which includes
75/// a sequence of instructions starting from FirstMI to LastMI (exclusive).
76/// This routine adds a BUNDLE instruction to represent the bundle, it adds
77/// IsInternalRead markers to MachineOperands which are defined inside the
78/// bundle, and it copies externally visible defs and uses to the BUNDLE
79/// instruction.
80void llvm::finalizeBundle(MachineBasicBlock &MBB,
81                          MachineBasicBlock::instr_iterator FirstMI,
82                          MachineBasicBlock::instr_iterator LastMI) {
83  assert(FirstMI != LastMI && "Empty bundle?");
84
85  const TargetMachine &TM = MBB.getParent()->getTarget();
86  const TargetInstrInfo *TII = TM.getInstrInfo();
87  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
88
89  MachineInstrBuilder MIB = BuildMI(MBB, FirstMI, FirstMI->getDebugLoc(),
90                                    TII->get(TargetOpcode::BUNDLE));
91
92  SmallVector<unsigned, 8> LocalDefs;
93  SmallSet<unsigned, 8> LocalDefSet;
94  SmallSet<unsigned, 8> DeadDefSet;
95  SmallSet<unsigned, 8> KilledDefSet;
96  SmallVector<unsigned, 8> ExternUses;
97  SmallSet<unsigned, 8> ExternUseSet;
98  SmallSet<unsigned, 8> KilledUseSet;
99  SmallSet<unsigned, 8> UndefUseSet;
100  SmallVector<MachineOperand*, 4> Defs;
101  for (; FirstMI != LastMI; ++FirstMI) {
102    for (unsigned i = 0, e = FirstMI->getNumOperands(); i != e; ++i) {
103      MachineOperand &MO = FirstMI->getOperand(i);
104      if (!MO.isReg())
105        continue;
106      if (MO.isDef()) {
107        Defs.push_back(&MO);
108        continue;
109      }
110
111      unsigned Reg = MO.getReg();
112      if (!Reg)
113        continue;
114      assert(TargetRegisterInfo::isPhysicalRegister(Reg));
115      if (LocalDefSet.count(Reg)) {
116        MO.setIsInternalRead();
117        if (MO.isKill())
118          // Internal def is now killed.
119          KilledDefSet.insert(Reg);
120      } else {
121        if (ExternUseSet.insert(Reg)) {
122          ExternUses.push_back(Reg);
123          if (MO.isUndef())
124            UndefUseSet.insert(Reg);
125        }
126        if (MO.isKill())
127          // External def is now killed.
128          KilledUseSet.insert(Reg);
129      }
130    }
131
132    for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
133      MachineOperand &MO = *Defs[i];
134      unsigned Reg = MO.getReg();
135      if (!Reg)
136        continue;
137
138      if (LocalDefSet.insert(Reg)) {
139        LocalDefs.push_back(Reg);
140        if (MO.isDead()) {
141          DeadDefSet.insert(Reg);
142        }
143      } else {
144        // Re-defined inside the bundle, it's no longer killed.
145        KilledDefSet.erase(Reg);
146        if (!MO.isDead())
147          // Previously defined but dead.
148          DeadDefSet.erase(Reg);
149      }
150
151      if (!MO.isDead()) {
152        for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
153             unsigned SubReg = *SubRegs; ++SubRegs) {
154          if (LocalDefSet.insert(SubReg))
155            LocalDefs.push_back(SubReg);
156        }
157      }
158    }
159
160    FirstMI->setIsInsideBundle();
161    Defs.clear();
162  }
163
164  SmallSet<unsigned, 8> Added;
165  for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
166    unsigned Reg = LocalDefs[i];
167    if (Added.insert(Reg)) {
168      // If it's not live beyond end of the bundle, mark it dead.
169      bool isDead = DeadDefSet.count(Reg) || KilledDefSet.count(Reg);
170      MIB.addReg(Reg, getDefRegState(true) | getDeadRegState(isDead) |
171                 getImplRegState(true));
172    }
173  }
174
175  for (unsigned i = 0, e = ExternUses.size(); i != e; ++i) {
176    unsigned Reg = ExternUses[i];
177    bool isKill = KilledUseSet.count(Reg);
178    bool isUndef = UndefUseSet.count(Reg);
179    MIB.addReg(Reg, getKillRegState(isKill) | getUndefRegState(isUndef) |
180               getImplRegState(true));
181  }
182}
183
184/// finalizeBundle - Same functionality as the previous finalizeBundle except
185/// the last instruction in the bundle is not provided as an input. This is
186/// used in cases where bundles are pre-determined by marking instructions
187/// with 'InsideBundle' marker.
188void llvm::finalizeBundle(MachineBasicBlock &MBB,
189                          MachineBasicBlock::instr_iterator FirstMI) {
190  MachineBasicBlock::instr_iterator E = MBB.instr_end();
191  MachineBasicBlock::instr_iterator LastMI = llvm::next(FirstMI);
192  while (LastMI != E && LastMI->isInsideBundle())
193    ++LastMI;
194  finalizeBundle(MBB, FirstMI, LastMI);
195}
196