MachineFunction.cpp revision 6b61f5816e22ac7f7e009aaf3e11ccce7cfeb085 
1//===-- MachineFunction.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// Collect native machine code information for a function.  This allows
11// target-specific information about the generated code to be stored with each
12// function.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/DerivedTypes.h"
17#include "llvm/Function.h"
18#include "llvm/Instructions.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/Config/config.h"
21#include "llvm/CodeGen/MachineConstantPool.h"
22#include "llvm/CodeGen/MachineFunction.h"
23#include "llvm/CodeGen/MachineFunctionPass.h"
24#include "llvm/CodeGen/MachineFrameInfo.h"
25#include "llvm/CodeGen/MachineInstr.h"
26#include "llvm/CodeGen/MachineJumpTableInfo.h"
27#include "llvm/CodeGen/MachineRegisterInfo.h"
28#include "llvm/CodeGen/Passes.h"
29#include "llvm/Support/Debug.h"
30#include "llvm/Target/TargetData.h"
31#include "llvm/Target/TargetLowering.h"
32#include "llvm/Target/TargetMachine.h"
33#include "llvm/Target/TargetFrameInfo.h"
34#include "llvm/Support/GraphWriter.h"
35#include "llvm/Support/raw_ostream.h"
36using namespace llvm;
37
38namespace {
39  struct Printer : public MachineFunctionPass {
40    static char ID;
41
42    raw_ostream &OS;
43    const std::string Banner;
44
45    Printer(raw_ostream &os, const std::string &banner)
46      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
47
48    const char *getPassName() const { return "MachineFunction Printer"; }
49
50    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
51      AU.setPreservesAll();
52      MachineFunctionPass::getAnalysisUsage(AU);
53    }
54
55    bool runOnMachineFunction(MachineFunction &MF) {
56      OS << "# " << Banner << ":\n";
57      MF.print(OS);
58      return false;
59    }
60  };
61  char Printer::ID = 0;
62}
63
64/// Returns a newly-created MachineFunction Printer pass. The default banner is
65/// empty.
66///
67FunctionPass *llvm::createMachineFunctionPrinterPass(raw_ostream &OS,
68                                                     const std::string &Banner){
69  return new Printer(OS, Banner);
70}
71
72//===---------------------------------------------------------------------===//
73// MachineFunction implementation
74//===---------------------------------------------------------------------===//
75
76// Out of line virtual method.
77MachineFunctionInfo::~MachineFunctionInfo() {}
78
79void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
80  MBB->getParent()->DeleteMachineBasicBlock(MBB);
81}
82
83MachineFunction::MachineFunction(Function *F,
84                                 const TargetMachine &TM)
85  : Fn(F), Target(TM) {
86  if (TM.getRegisterInfo())
87    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
88                  MachineRegisterInfo(*TM.getRegisterInfo());
89  else
90    RegInfo = 0;
91  MFInfo = 0;
92  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
93                  MachineFrameInfo(*TM.getFrameInfo());
94  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
95                     MachineConstantPool(TM.getTargetData());
96  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
97
98  // Set up jump table.
99  const TargetData &TD = *TM.getTargetData();
100  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
101  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
102  unsigned TyAlignment = IsPic ?
103                       TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
104                               : TD.getPointerABIAlignment();
105  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
106                      MachineJumpTableInfo(EntrySize, TyAlignment);
107}
108
109MachineFunction::~MachineFunction() {
110  BasicBlocks.clear();
111  InstructionRecycler.clear(Allocator);
112  BasicBlockRecycler.clear(Allocator);
113  if (RegInfo) {
114    RegInfo->~MachineRegisterInfo();
115    Allocator.Deallocate(RegInfo);
116  }
117  if (MFInfo) {
118    MFInfo->~MachineFunctionInfo();
119    Allocator.Deallocate(MFInfo);
120  }
121  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
122  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
123  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
124}
125
126
127/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
128/// recomputes them.  This guarantees that the MBB numbers are sequential,
129/// dense, and match the ordering of the blocks within the function.  If a
130/// specific MachineBasicBlock is specified, only that block and those after
131/// it are renumbered.
132void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
133  if (empty()) { MBBNumbering.clear(); return; }
134  MachineFunction::iterator MBBI, E = end();
135  if (MBB == 0)
136    MBBI = begin();
137  else
138    MBBI = MBB;
139
140  // Figure out the block number this should have.
141  unsigned BlockNo = 0;
142  if (MBBI != begin())
143    BlockNo = prior(MBBI)->getNumber()+1;
144
145  for (; MBBI != E; ++MBBI, ++BlockNo) {
146    if (MBBI->getNumber() != (int)BlockNo) {
147      // Remove use of the old number.
148      if (MBBI->getNumber() != -1) {
149        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
150               "MBB number mismatch!");
151        MBBNumbering[MBBI->getNumber()] = 0;
152      }
153
154      // If BlockNo is already taken, set that block's number to -1.
155      if (MBBNumbering[BlockNo])
156        MBBNumbering[BlockNo]->setNumber(-1);
157
158      MBBNumbering[BlockNo] = MBBI;
159      MBBI->setNumber(BlockNo);
160    }
161  }
162
163  // Okay, all the blocks are renumbered.  If we have compactified the block
164  // numbering, shrink MBBNumbering now.
165  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
166  MBBNumbering.resize(BlockNo);
167}
168
169/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
170/// of `new MachineInstr'.
171///
172MachineInstr *
173MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
174                                    DebugLoc DL, bool NoImp) {
175  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
176    MachineInstr(TID, DL, NoImp);
177}
178
179/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
180/// 'Orig' instruction, identical in all ways except the the instruction
181/// has no parent, prev, or next.
182///
183MachineInstr *
184MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
185  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
186             MachineInstr(*this, *Orig);
187}
188
189/// DeleteMachineInstr - Delete the given MachineInstr.
190///
191void
192MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
193  MI->~MachineInstr();
194  InstructionRecycler.Deallocate(Allocator, MI);
195}
196
197/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
198/// instead of `new MachineBasicBlock'.
199///
200MachineBasicBlock *
201MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
202  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
203             MachineBasicBlock(*this, bb);
204}
205
206/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
207///
208void
209MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
210  assert(MBB->getParent() == this && "MBB parent mismatch!");
211  MBB->~MachineBasicBlock();
212  BasicBlockRecycler.Deallocate(Allocator, MBB);
213}
214
215MachineMemOperand *
216MachineFunction::getMachineMemOperand(const Value *v, unsigned f,
217                                      int64_t o, uint64_t s,
218                                      unsigned base_alignment) {
219  return new (Allocator.Allocate<MachineMemOperand>())
220             MachineMemOperand(v, f, o, s, base_alignment);
221}
222
223MachineMemOperand *
224MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
225                                      int64_t Offset, uint64_t Size) {
226  return new (Allocator.Allocate<MachineMemOperand>())
227             MachineMemOperand(MMO->getValue(), MMO->getFlags(),
228                               int64_t(uint64_t(MMO->getOffset()) +
229                                       uint64_t(Offset)),
230                               Size, MMO->getBaseAlignment());
231}
232
233MachineInstr::mmo_iterator
234MachineFunction::allocateMemRefsArray(unsigned long Num) {
235  return Allocator.Allocate<MachineMemOperand *>(Num);
236}
237
238std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
239MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
240                                    MachineInstr::mmo_iterator End) {
241  // Count the number of load mem refs.
242  unsigned Num = 0;
243  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
244    if ((*I)->isLoad())
245      ++Num;
246
247  // Allocate a new array and populate it with the load information.
248  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
249  unsigned Index = 0;
250  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
251    if ((*I)->isLoad()) {
252      if (!(*I)->isStore())
253        // Reuse the MMO.
254        Result[Index] = *I;
255      else {
256        // Clone the MMO and unset the store flag.
257        MachineMemOperand *JustLoad =
258          getMachineMemOperand((*I)->getValue(),
259                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
260                               (*I)->getOffset(), (*I)->getSize(),
261                               (*I)->getBaseAlignment());
262        Result[Index] = JustLoad;
263      }
264      ++Index;
265    }
266  }
267  return std::make_pair(Result, Result + Num);
268}
269
270std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
271MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
272                                     MachineInstr::mmo_iterator End) {
273  // Count the number of load mem refs.
274  unsigned Num = 0;
275  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
276    if ((*I)->isStore())
277      ++Num;
278
279  // Allocate a new array and populate it with the store information.
280  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
281  unsigned Index = 0;
282  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
283    if ((*I)->isStore()) {
284      if (!(*I)->isLoad())
285        // Reuse the MMO.
286        Result[Index] = *I;
287      else {
288        // Clone the MMO and unset the load flag.
289        MachineMemOperand *JustStore =
290          getMachineMemOperand((*I)->getValue(),
291                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
292                               (*I)->getOffset(), (*I)->getSize(),
293                               (*I)->getBaseAlignment());
294        Result[Index] = JustStore;
295      }
296      ++Index;
297    }
298  }
299  return std::make_pair(Result, Result + Num);
300}
301
302void MachineFunction::dump() const {
303  print(dbgs());
304}
305
306void MachineFunction::print(raw_ostream &OS) const {
307  OS << "# Machine code for function " << Fn->getName() << ":\n";
308
309  // Print Frame Information
310  FrameInfo->print(*this, OS);
311
312  // Print JumpTable Information
313  JumpTableInfo->print(OS);
314
315  // Print Constant Pool
316  ConstantPool->print(OS);
317
318  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
319
320  if (RegInfo && !RegInfo->livein_empty()) {
321    OS << "Function Live Ins: ";
322    for (MachineRegisterInfo::livein_iterator
323         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
324      if (TRI)
325        OS << "%" << TRI->getName(I->first);
326      else
327        OS << " %physreg" << I->first;
328
329      if (I->second)
330        OS << " in reg%" << I->second;
331
332      if (llvm::next(I) != E)
333        OS << ", ";
334    }
335    OS << '\n';
336  }
337  if (RegInfo && !RegInfo->liveout_empty()) {
338    OS << "Function Live Outs: ";
339    for (MachineRegisterInfo::liveout_iterator
340         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I){
341      if (TRI)
342        OS << '%' << TRI->getName(*I);
343      else
344        OS << "%physreg" << *I;
345
346      if (llvm::next(I) != E)
347        OS << " ";
348    }
349    OS << '\n';
350  }
351
352  for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
353    OS << '\n';
354    BB->print(OS);
355  }
356
357  OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
358}
359
360namespace llvm {
361  template<>
362  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
363
364  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
365
366    static std::string getGraphName(const MachineFunction *F) {
367      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
368    }
369
370    std::string getNodeLabel(const MachineBasicBlock *Node,
371                             const MachineFunction *Graph) {
372      if (isSimple () && Node->getBasicBlock() &&
373          !Node->getBasicBlock()->getName().empty())
374        return Node->getBasicBlock()->getNameStr() + ":";
375
376      std::string OutStr;
377      {
378        raw_string_ostream OSS(OutStr);
379
380        if (isSimple())
381          OSS << Node->getNumber() << ':';
382        else
383          Node->print(OSS);
384      }
385
386      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
387
388      // Process string output to make it nicer...
389      for (unsigned i = 0; i != OutStr.length(); ++i)
390        if (OutStr[i] == '\n') {                            // Left justify
391          OutStr[i] = '\\';
392          OutStr.insert(OutStr.begin()+i+1, 'l');
393        }
394      return OutStr;
395    }
396  };
397}
398
399void MachineFunction::viewCFG() const
400{
401#ifndef NDEBUG
402  ViewGraph(this, "mf" + getFunction()->getNameStr());
403#else
404  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
405         << "systems with Graphviz or gv!\n";
406#endif // NDEBUG
407}
408
409void MachineFunction::viewCFGOnly() const
410{
411#ifndef NDEBUG
412  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
413#else
414  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
415         << "systems with Graphviz or gv!\n";
416#endif // NDEBUG
417}
418
419/// addLiveIn - Add the specified physical register as a live-in value and
420/// create a corresponding virtual register for it.
421unsigned MachineFunction::addLiveIn(unsigned PReg,
422                                    const TargetRegisterClass *RC) {
423  assert(RC->contains(PReg) && "Not the correct regclass!");
424  unsigned VReg = getRegInfo().createVirtualRegister(RC);
425  getRegInfo().addLiveIn(PReg, VReg);
426  return VReg;
427}
428
429/// getDILocation - Get the DILocation for a given DebugLoc object.
430DILocation MachineFunction::getDILocation(DebugLoc DL) const {
431  unsigned Idx = DL.getIndex();
432  assert(Idx < DebugLocInfo.DebugLocations.size() &&
433         "Invalid index into debug locations!");
434  return DILocation(DebugLocInfo.DebugLocations[Idx]);
435}
436
437//===----------------------------------------------------------------------===//
438//  MachineFrameInfo implementation
439//===----------------------------------------------------------------------===//
440
441/// CreateFixedObject - Create a new object at a fixed location on the stack.
442/// All fixed objects should be created before other objects are created for
443/// efficiency. By default, fixed objects are immutable. This returns an
444/// index with a negative value.
445///
446int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
447                                        bool Immutable, bool isSS) {
448  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
449  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
450                                              isSS));
451  return -++NumFixedObjects;
452}
453
454
455BitVector
456MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
457  assert(MBB && "MBB must be valid");
458  const MachineFunction *MF = MBB->getParent();
459  assert(MF && "MBB must be part of a MachineFunction");
460  const TargetMachine &TM = MF->getTarget();
461  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
462  BitVector BV(TRI->getNumRegs());
463
464  // Before CSI is calculated, no registers are considered pristine. They can be
465  // freely used and PEI will make sure they are saved.
466  if (!isCalleeSavedInfoValid())
467    return BV;
468
469  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
470    BV.set(*CSR);
471
472  // The entry MBB always has all CSRs pristine.
473  if (MBB == &MF->front())
474    return BV;
475
476  // On other MBBs the saved CSRs are not pristine.
477  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
478  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
479         E = CSI.end(); I != E; ++I)
480    BV.reset(I->getReg());
481
482  return BV;
483}
484
485
486void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
487  if (Objects.empty()) return;
488
489  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
490  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
491
492  OS << "Frame Objects:\n";
493
494  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
495    const StackObject &SO = Objects[i];
496    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
497    if (SO.Size == ~0ULL) {
498      OS << "dead\n";
499      continue;
500    }
501    if (SO.Size == 0)
502      OS << "variable sized";
503    else
504      OS << "size=" << SO.Size;
505    OS << ", align=" << SO.Alignment;
506
507    if (i < NumFixedObjects)
508      OS << ", fixed";
509    if (i < NumFixedObjects || SO.SPOffset != -1) {
510      int64_t Off = SO.SPOffset - ValOffset;
511      OS << ", at location [SP";
512      if (Off > 0)
513        OS << "+" << Off;
514      else if (Off < 0)
515        OS << Off;
516      OS << "]";
517    }
518    OS << "\n";
519  }
520}
521
522void MachineFrameInfo::dump(const MachineFunction &MF) const {
523  print(MF, dbgs());
524}
525
526//===----------------------------------------------------------------------===//
527//  MachineJumpTableInfo implementation
528//===----------------------------------------------------------------------===//
529
530/// getJumpTableIndex - Create a new jump table entry in the jump table info
531/// or return an existing one.
532///
533unsigned MachineJumpTableInfo::getJumpTableIndex(
534                               const std::vector<MachineBasicBlock*> &DestBBs) {
535  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
536  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
537  return JumpTables.size()-1;
538}
539
540/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
541/// the jump tables to branch to New instead.
542bool
543MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
544                                             MachineBasicBlock *New) {
545  assert(Old != New && "Not making a change?");
546  bool MadeChange = false;
547  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
548    ReplaceMBBInJumpTable(i, Old, New);
549  return MadeChange;
550}
551
552/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
553/// the jump table to branch to New instead.
554bool
555MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
556                                            MachineBasicBlock *Old,
557                                            MachineBasicBlock *New) {
558  assert(Old != New && "Not making a change?");
559  bool MadeChange = false;
560  MachineJumpTableEntry &JTE = JumpTables[Idx];
561  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
562    if (JTE.MBBs[j] == Old) {
563      JTE.MBBs[j] = New;
564      MadeChange = true;
565    }
566  return MadeChange;
567}
568
569void MachineJumpTableInfo::print(raw_ostream &OS) const {
570  if (JumpTables.empty()) return;
571
572  OS << "Jump Tables:\n";
573
574  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
575    OS << "  jt#" << i << ": ";
576    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
577      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
578  }
579
580  OS << '\n';
581}
582
583void MachineJumpTableInfo::dump() const { print(dbgs()); }
584
585
586//===----------------------------------------------------------------------===//
587//  MachineConstantPool implementation
588//===----------------------------------------------------------------------===//
589
590const Type *MachineConstantPoolEntry::getType() const {
591  if (isMachineConstantPoolEntry())
592    return Val.MachineCPVal->getType();
593  return Val.ConstVal->getType();
594}
595
596
597unsigned MachineConstantPoolEntry::getRelocationInfo() const {
598  if (isMachineConstantPoolEntry())
599    return Val.MachineCPVal->getRelocationInfo();
600  return Val.ConstVal->getRelocationInfo();
601}
602
603MachineConstantPool::~MachineConstantPool() {
604  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
605    if (Constants[i].isMachineConstantPoolEntry())
606      delete Constants[i].Val.MachineCPVal;
607}
608
609/// CanShareConstantPoolEntry - Test whether the given two constants
610/// can be allocated the same constant pool entry.
611static bool CanShareConstantPoolEntry(Constant *A, Constant *B,
612                                      const TargetData *TD) {
613  // Handle the trivial case quickly.
614  if (A == B) return true;
615
616  // If they have the same type but weren't the same constant, quickly
617  // reject them.
618  if (A->getType() == B->getType()) return false;
619
620  // For now, only support constants with the same size.
621  if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
622    return false;
623
624  // If a floating-point value and an integer value have the same encoding,
625  // they can share a constant-pool entry.
626  if (ConstantFP *AFP = dyn_cast<ConstantFP>(A))
627    if (ConstantInt *BI = dyn_cast<ConstantInt>(B))
628      return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
629  if (ConstantFP *BFP = dyn_cast<ConstantFP>(B))
630    if (ConstantInt *AI = dyn_cast<ConstantInt>(A))
631      return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
632
633  // Two vectors can share an entry if each pair of corresponding
634  // elements could.
635  if (ConstantVector *AV = dyn_cast<ConstantVector>(A))
636    if (ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
637      if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
638        return false;
639      for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
640        if (!CanShareConstantPoolEntry(AV->getOperand(i),
641                                       BV->getOperand(i), TD))
642          return false;
643      return true;
644    }
645
646  // TODO: Handle other cases.
647
648  return false;
649}
650
651/// getConstantPoolIndex - Create a new entry in the constant pool or return
652/// an existing one.  User must specify the log2 of the minimum required
653/// alignment for the object.
654///
655unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
656                                                   unsigned Alignment) {
657  assert(Alignment && "Alignment must be specified!");
658  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
659
660  // Check to see if we already have this constant.
661  //
662  // FIXME, this could be made much more efficient for large constant pools.
663  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
664    if (!Constants[i].isMachineConstantPoolEntry() &&
665        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
666      if ((unsigned)Constants[i].getAlignment() < Alignment)
667        Constants[i].Alignment = Alignment;
668      return i;
669    }
670
671  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
672  return Constants.size()-1;
673}
674
675unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
676                                                   unsigned Alignment) {
677  assert(Alignment && "Alignment must be specified!");
678  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
679
680  // Check to see if we already have this constant.
681  //
682  // FIXME, this could be made much more efficient for large constant pools.
683  int Idx = V->getExistingMachineCPValue(this, Alignment);
684  if (Idx != -1)
685    return (unsigned)Idx;
686
687  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
688  return Constants.size()-1;
689}
690
691void MachineConstantPool::print(raw_ostream &OS) const {
692  if (Constants.empty()) return;
693
694  OS << "Constant Pool:\n";
695  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
696    OS << "  cp#" << i << ": ";
697    if (Constants[i].isMachineConstantPoolEntry())
698      Constants[i].Val.MachineCPVal->print(OS);
699    else
700      OS << *(Value*)Constants[i].Val.ConstVal;
701    OS << ", align=" << Constants[i].getAlignment();
702    OS << "\n";
703  }
704}
705
706void MachineConstantPool::dump() const { print(dbgs()); }
707