MachineFunction.cpp revision 68bb60f6a4e0902769f72d1badda4e37cd873ffb 
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/Target/TargetData.h"
30#include "llvm/Target/TargetLowering.h"
31#include "llvm/Target/TargetMachine.h"
32#include "llvm/Target/TargetFrameInfo.h"
33#include "llvm/Support/GraphWriter.h"
34#include "llvm/Support/raw_ostream.h"
35using namespace llvm;
36
37namespace {
38  struct Printer : public MachineFunctionPass {
39    static char ID;
40
41    raw_ostream &OS;
42    const std::string Banner;
43
44    Printer(raw_ostream &os, const std::string &banner)
45      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
46
47    const char *getPassName() const { return "MachineFunction Printer"; }
48
49    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
50      AU.setPreservesAll();
51      MachineFunctionPass::getAnalysisUsage(AU);
52    }
53
54    bool runOnMachineFunction(MachineFunction &MF) {
55      OS << "# " << Banner << ":\n";
56      MF.print(OS);
57      return false;
58    }
59  };
60  char Printer::ID = 0;
61}
62
63/// Returns a newly-created MachineFunction Printer pass. The default banner is
64/// empty.
65///
66FunctionPass *llvm::createMachineFunctionPrinterPass(raw_ostream &OS,
67                                                     const std::string &Banner){
68  return new Printer(OS, Banner);
69}
70
71//===---------------------------------------------------------------------===//
72// MachineFunction implementation
73//===---------------------------------------------------------------------===//
74
75// Out of line virtual method.
76MachineFunctionInfo::~MachineFunctionInfo() {}
77
78void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
79  MBB->getParent()->DeleteMachineBasicBlock(MBB);
80}
81
82MachineFunction::MachineFunction(Function *F,
83                                 const TargetMachine &TM)
84  : Fn(F), Target(TM) {
85  if (TM.getRegisterInfo())
86    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
87                  MachineRegisterInfo(*TM.getRegisterInfo());
88  else
89    RegInfo = 0;
90  MFInfo = 0;
91  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
92                  MachineFrameInfo(*TM.getFrameInfo());
93  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
94                     MachineConstantPool(TM.getTargetData());
95  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
96
97  // Set up jump table.
98  const TargetData &TD = *TM.getTargetData();
99  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
100  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
101  unsigned TyAlignment = IsPic ?
102                       TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
103                               : TD.getPointerABIAlignment();
104  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
105                      MachineJumpTableInfo(EntrySize, TyAlignment);
106}
107
108MachineFunction::~MachineFunction() {
109  BasicBlocks.clear();
110  InstructionRecycler.clear(Allocator);
111  BasicBlockRecycler.clear(Allocator);
112  if (RegInfo) {
113    RegInfo->~MachineRegisterInfo();
114    Allocator.Deallocate(RegInfo);
115  }
116  if (MFInfo) {
117    MFInfo->~MachineFunctionInfo();
118    Allocator.Deallocate(MFInfo);
119  }
120  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
121  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
122  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
123}
124
125
126/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
127/// recomputes them.  This guarantees that the MBB numbers are sequential,
128/// dense, and match the ordering of the blocks within the function.  If a
129/// specific MachineBasicBlock is specified, only that block and those after
130/// it are renumbered.
131void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
132  if (empty()) { MBBNumbering.clear(); return; }
133  MachineFunction::iterator MBBI, E = end();
134  if (MBB == 0)
135    MBBI = begin();
136  else
137    MBBI = MBB;
138
139  // Figure out the block number this should have.
140  unsigned BlockNo = 0;
141  if (MBBI != begin())
142    BlockNo = prior(MBBI)->getNumber()+1;
143
144  for (; MBBI != E; ++MBBI, ++BlockNo) {
145    if (MBBI->getNumber() != (int)BlockNo) {
146      // Remove use of the old number.
147      if (MBBI->getNumber() != -1) {
148        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
149               "MBB number mismatch!");
150        MBBNumbering[MBBI->getNumber()] = 0;
151      }
152
153      // If BlockNo is already taken, set that block's number to -1.
154      if (MBBNumbering[BlockNo])
155        MBBNumbering[BlockNo]->setNumber(-1);
156
157      MBBNumbering[BlockNo] = MBBI;
158      MBBI->setNumber(BlockNo);
159    }
160  }
161
162  // Okay, all the blocks are renumbered.  If we have compactified the block
163  // numbering, shrink MBBNumbering now.
164  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
165  MBBNumbering.resize(BlockNo);
166}
167
168/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
169/// of `new MachineInstr'.
170///
171MachineInstr *
172MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
173                                    DebugLoc DL, bool NoImp) {
174  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
175    MachineInstr(TID, DL, NoImp);
176}
177
178/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
179/// 'Orig' instruction, identical in all ways except the the instruction
180/// has no parent, prev, or next.
181///
182MachineInstr *
183MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
184  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
185             MachineInstr(*this, *Orig);
186}
187
188/// DeleteMachineInstr - Delete the given MachineInstr.
189///
190void
191MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
192  MI->~MachineInstr();
193  InstructionRecycler.Deallocate(Allocator, MI);
194}
195
196/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
197/// instead of `new MachineBasicBlock'.
198///
199MachineBasicBlock *
200MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
201  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
202             MachineBasicBlock(*this, bb);
203}
204
205/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
206///
207void
208MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
209  assert(MBB->getParent() == this && "MBB parent mismatch!");
210  MBB->~MachineBasicBlock();
211  BasicBlockRecycler.Deallocate(Allocator, MBB);
212}
213
214MachineMemOperand *
215MachineFunction::getMachineMemOperand(const Value *v, unsigned f,
216                                      int64_t o, uint64_t s,
217                                      unsigned base_alignment) {
218  return new (Allocator.Allocate<MachineMemOperand>())
219             MachineMemOperand(v, f, o, s, base_alignment);
220}
221
222MachineMemOperand *
223MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
224                                      int64_t Offset, uint64_t Size) {
225  return new (Allocator.Allocate<MachineMemOperand>())
226             MachineMemOperand(MMO->getValue(), MMO->getFlags(),
227                               int64_t(uint64_t(MMO->getOffset()) +
228                                       uint64_t(Offset)),
229                               Size, MMO->getBaseAlignment());
230}
231
232MachineInstr::mmo_iterator
233MachineFunction::allocateMemRefsArray(unsigned long Num) {
234  return Allocator.Allocate<MachineMemOperand *>(Num);
235}
236
237std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
238MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
239                                    MachineInstr::mmo_iterator End) {
240  // Count the number of load mem refs.
241  unsigned Num = 0;
242  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
243    if ((*I)->isLoad())
244      ++Num;
245
246  // Allocate a new array and populate it with the load information.
247  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
248  unsigned Index = 0;
249  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
250    if ((*I)->isLoad()) {
251      if (!(*I)->isStore())
252        // Reuse the MMO.
253        Result[Index] = *I;
254      else {
255        // Clone the MMO and unset the store flag.
256        MachineMemOperand *JustLoad =
257          getMachineMemOperand((*I)->getValue(),
258                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
259                               (*I)->getOffset(), (*I)->getSize(),
260                               (*I)->getBaseAlignment());
261        Result[Index] = JustLoad;
262      }
263      ++Index;
264    }
265  }
266  return std::make_pair(Result, Result + Num);
267}
268
269std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
270MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
271                                     MachineInstr::mmo_iterator End) {
272  // Count the number of load mem refs.
273  unsigned Num = 0;
274  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
275    if ((*I)->isStore())
276      ++Num;
277
278  // Allocate a new array and populate it with the store information.
279  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
280  unsigned Index = 0;
281  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
282    if ((*I)->isStore()) {
283      if (!(*I)->isLoad())
284        // Reuse the MMO.
285        Result[Index] = *I;
286      else {
287        // Clone the MMO and unset the load flag.
288        MachineMemOperand *JustStore =
289          getMachineMemOperand((*I)->getValue(),
290                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
291                               (*I)->getOffset(), (*I)->getSize(),
292                               (*I)->getBaseAlignment());
293        Result[Index] = JustStore;
294      }
295      ++Index;
296    }
297  }
298  return std::make_pair(Result, Result + Num);
299}
300
301void MachineFunction::dump() const {
302  print(errs());
303}
304
305void MachineFunction::print(raw_ostream &OS) const {
306  OS << "# Machine code for function " << Fn->getName() << ":\n";
307
308  // Print Frame Information
309  FrameInfo->print(*this, OS);
310
311  // Print JumpTable Information
312  JumpTableInfo->print(OS);
313
314  // Print Constant Pool
315  ConstantPool->print(OS);
316
317  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
318
319  if (RegInfo && !RegInfo->livein_empty()) {
320    OS << "Function Live Ins: ";
321    for (MachineRegisterInfo::livein_iterator
322         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
323      if (TRI)
324        OS << "%" << TRI->getName(I->first);
325      else
326        OS << " %physreg" << I->first;
327
328      if (I->second)
329        OS << " in reg%" << I->second;
330
331      if (next(I) != E)
332        OS << ", ";
333    }
334    OS << '\n';
335  }
336  if (RegInfo && !RegInfo->liveout_empty()) {
337    OS << "Function Live Outs: ";
338    for (MachineRegisterInfo::liveout_iterator
339         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I){
340      if (TRI)
341        OS << '%' << TRI->getName(*I);
342      else
343        OS << "%physreg" << *I;
344
345      if (next(I) != E)
346        OS << " ";
347    }
348    OS << '\n';
349  }
350
351  for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
352    OS << '\n';
353    BB->print(OS);
354  }
355
356  OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
357}
358
359namespace llvm {
360  template<>
361  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
362    static std::string getGraphName(const MachineFunction *F) {
363      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
364    }
365
366    static std::string getNodeLabel(const MachineBasicBlock *Node,
367                                    const MachineFunction *Graph,
368                                    bool ShortNames) {
369      if (ShortNames && Node->getBasicBlock() &&
370          !Node->getBasicBlock()->getName().empty())
371        return Node->getBasicBlock()->getNameStr() + ":";
372
373      std::string OutStr;
374      {
375        raw_string_ostream OSS(OutStr);
376
377        if (ShortNames)
378          OSS << Node->getNumber() << ':';
379        else
380          Node->print(OSS);
381      }
382
383      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
384
385      // Process string output to make it nicer...
386      for (unsigned i = 0; i != OutStr.length(); ++i)
387        if (OutStr[i] == '\n') {                            // Left justify
388          OutStr[i] = '\\';
389          OutStr.insert(OutStr.begin()+i+1, 'l');
390        }
391      return OutStr;
392    }
393  };
394}
395
396void MachineFunction::viewCFG() const
397{
398#ifndef NDEBUG
399  ViewGraph(this, "mf" + getFunction()->getNameStr());
400#else
401  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
402         << "systems with Graphviz or gv!\n";
403#endif // NDEBUG
404}
405
406void MachineFunction::viewCFGOnly() const
407{
408#ifndef NDEBUG
409  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
410#else
411  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
412         << "systems with Graphviz or gv!\n";
413#endif // NDEBUG
414}
415
416/// addLiveIn - Add the specified physical register as a live-in value and
417/// create a corresponding virtual register for it.
418unsigned MachineFunction::addLiveIn(unsigned PReg,
419                                    const TargetRegisterClass *RC) {
420  assert(RC->contains(PReg) && "Not the correct regclass!");
421  unsigned VReg = getRegInfo().createVirtualRegister(RC);
422  getRegInfo().addLiveIn(PReg, VReg);
423  return VReg;
424}
425
426/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
427DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
428  unsigned Idx = DL.getIndex();
429  assert(Idx < DebugLocInfo.DebugLocations.size() &&
430         "Invalid index into debug locations!");
431  return DebugLocInfo.DebugLocations[Idx];
432}
433
434//===----------------------------------------------------------------------===//
435//  MachineFrameInfo implementation
436//===----------------------------------------------------------------------===//
437
438/// CreateFixedObject - Create a new object at a fixed location on the stack.
439/// All fixed objects should be created before other objects are created for
440/// efficiency. By default, fixed objects are immutable. This returns an
441/// index with a negative value.
442///
443int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
444                                        bool Immutable, bool isSS) {
445  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
446  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
447                                              isSS));
448  return -++NumFixedObjects;
449}
450
451
452BitVector
453MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
454  assert(MBB && "MBB must be valid");
455  const MachineFunction *MF = MBB->getParent();
456  assert(MF && "MBB must be part of a MachineFunction");
457  const TargetMachine &TM = MF->getTarget();
458  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
459  BitVector BV(TRI->getNumRegs());
460
461  // Before CSI is calculated, no registers are considered pristine. They can be
462  // freely used and PEI will make sure they are saved.
463  if (!isCalleeSavedInfoValid())
464    return BV;
465
466  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
467    BV.set(*CSR);
468
469  // The entry MBB always has all CSRs pristine.
470  if (MBB == &MF->front())
471    return BV;
472
473  // On other MBBs the saved CSRs are not pristine.
474  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
475  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
476         E = CSI.end(); I != E; ++I)
477    BV.reset(I->getReg());
478
479  return BV;
480}
481
482
483void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
484  if (Objects.empty()) return;
485
486  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
487  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
488
489  OS << "Frame Objects:\n";
490
491  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
492    const StackObject &SO = Objects[i];
493    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
494    if (SO.Size == ~0ULL) {
495      OS << "dead\n";
496      continue;
497    }
498    if (SO.Size == 0)
499      OS << "variable sized";
500    else
501      OS << "size=" << SO.Size;
502    OS << ", align=" << SO.Alignment;
503
504    if (i < NumFixedObjects)
505      OS << ", fixed";
506    if (i < NumFixedObjects || SO.SPOffset != -1) {
507      int64_t Off = SO.SPOffset - ValOffset;
508      OS << ", at location [SP";
509      if (Off > 0)
510        OS << "+" << Off;
511      else if (Off < 0)
512        OS << Off;
513      OS << "]";
514    }
515    OS << "\n";
516  }
517}
518
519void MachineFrameInfo::dump(const MachineFunction &MF) const {
520  print(MF, errs());
521}
522
523//===----------------------------------------------------------------------===//
524//  MachineJumpTableInfo implementation
525//===----------------------------------------------------------------------===//
526
527/// getJumpTableIndex - Create a new jump table entry in the jump table info
528/// or return an existing one.
529///
530unsigned MachineJumpTableInfo::getJumpTableIndex(
531                               const std::vector<MachineBasicBlock*> &DestBBs) {
532  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
533  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
534    if (JumpTables[i].MBBs == DestBBs)
535      return i;
536
537  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
538  return JumpTables.size()-1;
539}
540
541/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
542/// the jump tables to branch to New instead.
543bool
544MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
545                                             MachineBasicBlock *New) {
546  assert(Old != New && "Not making a change?");
547  bool MadeChange = false;
548  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
549    ReplaceMBBInJumpTable(i, Old, New);
550  return MadeChange;
551}
552
553/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
554/// the jump table to branch to New instead.
555bool
556MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
557                                            MachineBasicBlock *Old,
558                                            MachineBasicBlock *New) {
559  assert(Old != New && "Not making a change?");
560  bool MadeChange = false;
561  MachineJumpTableEntry &JTE = JumpTables[Idx];
562  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
563    if (JTE.MBBs[j] == Old) {
564      JTE.MBBs[j] = New;
565      MadeChange = true;
566    }
567  return MadeChange;
568}
569
570void MachineJumpTableInfo::print(raw_ostream &OS) const {
571  if (JumpTables.empty()) return;
572
573  OS << "Jump Tables:\n";
574
575  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
576    OS << "  jt#" << i << ": ";
577    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
578      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
579  }
580
581  OS << '\n';
582}
583
584void MachineJumpTableInfo::dump() const { print(errs()); }
585
586
587//===----------------------------------------------------------------------===//
588//  MachineConstantPool implementation
589//===----------------------------------------------------------------------===//
590
591const Type *MachineConstantPoolEntry::getType() const {
592  if (isMachineConstantPoolEntry())
593    return Val.MachineCPVal->getType();
594  return Val.ConstVal->getType();
595}
596
597
598unsigned MachineConstantPoolEntry::getRelocationInfo() const {
599  if (isMachineConstantPoolEntry())
600    return Val.MachineCPVal->getRelocationInfo();
601  return Val.ConstVal->getRelocationInfo();
602}
603
604MachineConstantPool::~MachineConstantPool() {
605  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
606    if (Constants[i].isMachineConstantPoolEntry())
607      delete Constants[i].Val.MachineCPVal;
608}
609
610/// CanShareConstantPoolEntry - Test whether the given two constants
611/// can be allocated the same constant pool entry.
612static bool CanShareConstantPoolEntry(Constant *A, Constant *B,
613                                      const TargetData *TD) {
614  // Handle the trivial case quickly.
615  if (A == B) return true;
616
617  // If they have the same type but weren't the same constant, quickly
618  // reject them.
619  if (A->getType() == B->getType()) return false;
620
621  // For now, only support constants with the same size.
622  if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
623    return false;
624
625  // If a floating-point value and an integer value have the same encoding,
626  // they can share a constant-pool entry.
627  if (ConstantFP *AFP = dyn_cast<ConstantFP>(A))
628    if (ConstantInt *BI = dyn_cast<ConstantInt>(B))
629      return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
630  if (ConstantFP *BFP = dyn_cast<ConstantFP>(B))
631    if (ConstantInt *AI = dyn_cast<ConstantInt>(A))
632      return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
633
634  // Two vectors can share an entry if each pair of corresponding
635  // elements could.
636  if (ConstantVector *AV = dyn_cast<ConstantVector>(A))
637    if (ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
638      if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
639        return false;
640      for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
641        if (!CanShareConstantPoolEntry(AV->getOperand(i),
642                                       BV->getOperand(i), TD))
643          return false;
644      return true;
645    }
646
647  // TODO: Handle other cases.
648
649  return false;
650}
651
652/// getConstantPoolIndex - Create a new entry in the constant pool or return
653/// an existing one.  User must specify the log2 of the minimum required
654/// alignment for the object.
655///
656unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
657                                                   unsigned Alignment) {
658  assert(Alignment && "Alignment must be specified!");
659  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
660
661  // Check to see if we already have this constant.
662  //
663  // FIXME, this could be made much more efficient for large constant pools.
664  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
665    if (!Constants[i].isMachineConstantPoolEntry() &&
666        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
667      if ((unsigned)Constants[i].getAlignment() < Alignment)
668        Constants[i].Alignment = Alignment;
669      return i;
670    }
671
672  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
673  return Constants.size()-1;
674}
675
676unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
677                                                   unsigned Alignment) {
678  assert(Alignment && "Alignment must be specified!");
679  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
680
681  // Check to see if we already have this constant.
682  //
683  // FIXME, this could be made much more efficient for large constant pools.
684  int Idx = V->getExistingMachineCPValue(this, Alignment);
685  if (Idx != -1)
686    return (unsigned)Idx;
687
688  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
689  return Constants.size()-1;
690}
691
692void MachineConstantPool::print(raw_ostream &OS) const {
693  if (Constants.empty()) return;
694
695  OS << "Constant Pool:\n";
696  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
697    OS << "  cp#" << i << ": ";
698    if (Constants[i].isMachineConstantPoolEntry())
699      Constants[i].Val.MachineCPVal->print(OS);
700    else
701      OS << *(Value*)Constants[i].Val.ConstVal;
702    OS << ", align=" << Constants[i].getAlignment();
703    OS << "\n";
704  }
705}
706
707void MachineConstantPool::dump() const { print(errs()); }
708