MachineFunction.cpp revision 206124 
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/Config/config.h"
20#include "llvm/CodeGen/MachineConstantPool.h"
21#include "llvm/CodeGen/MachineFunction.h"
22#include "llvm/CodeGen/MachineFunctionPass.h"
23#include "llvm/CodeGen/MachineFrameInfo.h"
24#include "llvm/CodeGen/MachineInstr.h"
25#include "llvm/CodeGen/MachineJumpTableInfo.h"
26#include "llvm/CodeGen/MachineRegisterInfo.h"
27#include "llvm/CodeGen/Passes.h"
28#include "llvm/MC/MCAsmInfo.h"
29#include "llvm/MC/MCContext.h"
30#include "llvm/Analysis/DebugInfo.h"
31#include "llvm/Support/Debug.h"
32#include "llvm/Target/TargetData.h"
33#include "llvm/Target/TargetLowering.h"
34#include "llvm/Target/TargetMachine.h"
35#include "llvm/Target/TargetFrameInfo.h"
36#include "llvm/ADT/SmallString.h"
37#include "llvm/ADT/STLExtras.h"
38#include "llvm/Support/GraphWriter.h"
39#include "llvm/Support/raw_ostream.h"
40using namespace llvm;
41
42//===----------------------------------------------------------------------===//
43// MachineFunction implementation
44//===----------------------------------------------------------------------===//
45
46// Out of line virtual method.
47MachineFunctionInfo::~MachineFunctionInfo() {}
48
49void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
50  MBB->getParent()->DeleteMachineBasicBlock(MBB);
51}
52
53MachineFunction::MachineFunction(Function *F, const TargetMachine &TM,
54                                 unsigned FunctionNum, MCContext &ctx)
55  : Fn(F), Target(TM), Ctx(ctx) {
56  if (TM.getRegisterInfo())
57    RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
58  else
59    RegInfo = 0;
60  MFInfo = 0;
61  FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameInfo());
62  if (Fn->hasFnAttr(Attribute::StackAlignment))
63    FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
64        Fn->getAttributes().getFnAttributes()));
65  ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
66  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
67  FunctionNumber = FunctionNum;
68  JumpTableInfo = 0;
69}
70
71MachineFunction::~MachineFunction() {
72  BasicBlocks.clear();
73  InstructionRecycler.clear(Allocator);
74  BasicBlockRecycler.clear(Allocator);
75  if (RegInfo) {
76    RegInfo->~MachineRegisterInfo();
77    Allocator.Deallocate(RegInfo);
78  }
79  if (MFInfo) {
80    MFInfo->~MachineFunctionInfo();
81    Allocator.Deallocate(MFInfo);
82  }
83  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
84  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
85
86  if (JumpTableInfo) {
87    JumpTableInfo->~MachineJumpTableInfo();
88    Allocator.Deallocate(JumpTableInfo);
89  }
90}
91
92/// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
93/// does already exist, allocate one.
94MachineJumpTableInfo *MachineFunction::
95getOrCreateJumpTableInfo(unsigned EntryKind) {
96  if (JumpTableInfo) return JumpTableInfo;
97
98  JumpTableInfo = new (Allocator)
99    MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
100  return JumpTableInfo;
101}
102
103/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
104/// recomputes them.  This guarantees that the MBB numbers are sequential,
105/// dense, and match the ordering of the blocks within the function.  If a
106/// specific MachineBasicBlock is specified, only that block and those after
107/// it are renumbered.
108void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
109  if (empty()) { MBBNumbering.clear(); return; }
110  MachineFunction::iterator MBBI, E = end();
111  if (MBB == 0)
112    MBBI = begin();
113  else
114    MBBI = MBB;
115
116  // Figure out the block number this should have.
117  unsigned BlockNo = 0;
118  if (MBBI != begin())
119    BlockNo = prior(MBBI)->getNumber()+1;
120
121  for (; MBBI != E; ++MBBI, ++BlockNo) {
122    if (MBBI->getNumber() != (int)BlockNo) {
123      // Remove use of the old number.
124      if (MBBI->getNumber() != -1) {
125        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
126               "MBB number mismatch!");
127        MBBNumbering[MBBI->getNumber()] = 0;
128      }
129
130      // If BlockNo is already taken, set that block's number to -1.
131      if (MBBNumbering[BlockNo])
132        MBBNumbering[BlockNo]->setNumber(-1);
133
134      MBBNumbering[BlockNo] = MBBI;
135      MBBI->setNumber(BlockNo);
136    }
137  }
138
139  // Okay, all the blocks are renumbered.  If we have compactified the block
140  // numbering, shrink MBBNumbering now.
141  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
142  MBBNumbering.resize(BlockNo);
143}
144
145/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
146/// of `new MachineInstr'.
147///
148MachineInstr *
149MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
150                                    DebugLoc DL, bool NoImp) {
151  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
152    MachineInstr(TID, DL, NoImp);
153}
154
155/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
156/// 'Orig' instruction, identical in all ways except the instruction
157/// has no parent, prev, or next.
158///
159MachineInstr *
160MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
161  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
162             MachineInstr(*this, *Orig);
163}
164
165/// DeleteMachineInstr - Delete the given MachineInstr.
166///
167void
168MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
169  MI->~MachineInstr();
170  InstructionRecycler.Deallocate(Allocator, MI);
171}
172
173/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
174/// instead of `new MachineBasicBlock'.
175///
176MachineBasicBlock *
177MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
178  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
179             MachineBasicBlock(*this, bb);
180}
181
182/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
183///
184void
185MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
186  assert(MBB->getParent() == this && "MBB parent mismatch!");
187  MBB->~MachineBasicBlock();
188  BasicBlockRecycler.Deallocate(Allocator, MBB);
189}
190
191MachineMemOperand *
192MachineFunction::getMachineMemOperand(const Value *v, unsigned f,
193                                      int64_t o, uint64_t s,
194                                      unsigned base_alignment) {
195  return new (Allocator) MachineMemOperand(v, f, o, s, base_alignment);
196}
197
198MachineMemOperand *
199MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
200                                      int64_t Offset, uint64_t Size) {
201  return new (Allocator)
202             MachineMemOperand(MMO->getValue(), MMO->getFlags(),
203                               int64_t(uint64_t(MMO->getOffset()) +
204                                       uint64_t(Offset)),
205                               Size, MMO->getBaseAlignment());
206}
207
208MachineInstr::mmo_iterator
209MachineFunction::allocateMemRefsArray(unsigned long Num) {
210  return Allocator.Allocate<MachineMemOperand *>(Num);
211}
212
213std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
214MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
215                                    MachineInstr::mmo_iterator End) {
216  // Count the number of load mem refs.
217  unsigned Num = 0;
218  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
219    if ((*I)->isLoad())
220      ++Num;
221
222  // Allocate a new array and populate it with the load information.
223  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
224  unsigned Index = 0;
225  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
226    if ((*I)->isLoad()) {
227      if (!(*I)->isStore())
228        // Reuse the MMO.
229        Result[Index] = *I;
230      else {
231        // Clone the MMO and unset the store flag.
232        MachineMemOperand *JustLoad =
233          getMachineMemOperand((*I)->getValue(),
234                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
235                               (*I)->getOffset(), (*I)->getSize(),
236                               (*I)->getBaseAlignment());
237        Result[Index] = JustLoad;
238      }
239      ++Index;
240    }
241  }
242  return std::make_pair(Result, Result + Num);
243}
244
245std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
246MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
247                                     MachineInstr::mmo_iterator End) {
248  // Count the number of load mem refs.
249  unsigned Num = 0;
250  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
251    if ((*I)->isStore())
252      ++Num;
253
254  // Allocate a new array and populate it with the store information.
255  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
256  unsigned Index = 0;
257  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
258    if ((*I)->isStore()) {
259      if (!(*I)->isLoad())
260        // Reuse the MMO.
261        Result[Index] = *I;
262      else {
263        // Clone the MMO and unset the load flag.
264        MachineMemOperand *JustStore =
265          getMachineMemOperand((*I)->getValue(),
266                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
267                               (*I)->getOffset(), (*I)->getSize(),
268                               (*I)->getBaseAlignment());
269        Result[Index] = JustStore;
270      }
271      ++Index;
272    }
273  }
274  return std::make_pair(Result, Result + Num);
275}
276
277void MachineFunction::dump() const {
278  print(dbgs());
279}
280
281void MachineFunction::print(raw_ostream &OS) const {
282  OS << "# Machine code for function " << Fn->getName() << ":\n";
283
284  // Print Frame Information
285  FrameInfo->print(*this, OS);
286
287  // Print JumpTable Information
288  if (JumpTableInfo)
289    JumpTableInfo->print(OS);
290
291  // Print Constant Pool
292  ConstantPool->print(OS);
293
294  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
295
296  if (RegInfo && !RegInfo->livein_empty()) {
297    OS << "Function Live Ins: ";
298    for (MachineRegisterInfo::livein_iterator
299         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
300      if (TRI)
301        OS << "%" << TRI->getName(I->first);
302      else
303        OS << " %physreg" << I->first;
304
305      if (I->second)
306        OS << " in reg%" << I->second;
307
308      if (llvm::next(I) != E)
309        OS << ", ";
310    }
311    OS << '\n';
312  }
313  if (RegInfo && !RegInfo->liveout_empty()) {
314    OS << "Function Live Outs: ";
315    for (MachineRegisterInfo::liveout_iterator
316         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I){
317      if (TRI)
318        OS << '%' << TRI->getName(*I);
319      else
320        OS << "%physreg" << *I;
321
322      if (llvm::next(I) != E)
323        OS << " ";
324    }
325    OS << '\n';
326  }
327
328  for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
329    OS << '\n';
330    BB->print(OS);
331  }
332
333  OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
334}
335
336namespace llvm {
337  template<>
338  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
339
340  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
341
342    static std::string getGraphName(const MachineFunction *F) {
343      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
344    }
345
346    std::string getNodeLabel(const MachineBasicBlock *Node,
347                             const MachineFunction *Graph) {
348      if (isSimple () && Node->getBasicBlock() &&
349          !Node->getBasicBlock()->getName().empty())
350        return Node->getBasicBlock()->getNameStr() + ":";
351
352      std::string OutStr;
353      {
354        raw_string_ostream OSS(OutStr);
355
356        if (isSimple())
357          OSS << Node->getNumber() << ':';
358        else
359          Node->print(OSS);
360      }
361
362      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
363
364      // Process string output to make it nicer...
365      for (unsigned i = 0; i != OutStr.length(); ++i)
366        if (OutStr[i] == '\n') {                            // Left justify
367          OutStr[i] = '\\';
368          OutStr.insert(OutStr.begin()+i+1, 'l');
369        }
370      return OutStr;
371    }
372  };
373}
374
375void MachineFunction::viewCFG() const
376{
377#ifndef NDEBUG
378  ViewGraph(this, "mf" + getFunction()->getNameStr());
379#else
380  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
381         << "systems with Graphviz or gv!\n";
382#endif // NDEBUG
383}
384
385void MachineFunction::viewCFGOnly() const
386{
387#ifndef NDEBUG
388  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
389#else
390  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
391         << "systems with Graphviz or gv!\n";
392#endif // NDEBUG
393}
394
395/// addLiveIn - Add the specified physical register as a live-in value and
396/// create a corresponding virtual register for it.
397unsigned MachineFunction::addLiveIn(unsigned PReg,
398                                    const TargetRegisterClass *RC) {
399  assert(RC->contains(PReg) && "Not the correct regclass!");
400  unsigned VReg = getRegInfo().createVirtualRegister(RC);
401  getRegInfo().addLiveIn(PReg, VReg);
402  return VReg;
403}
404
405/// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
406/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
407/// normal 'L' label is returned.
408MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
409                                        bool isLinkerPrivate) const {
410  assert(JumpTableInfo && "No jump tables");
411
412  assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
413  const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
414
415  const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
416                                         MAI.getPrivateGlobalPrefix();
417  SmallString<60> Name;
418  raw_svector_ostream(Name)
419    << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
420  return Ctx.GetOrCreateSymbol(Name.str());
421}
422
423
424//===----------------------------------------------------------------------===//
425//  MachineFrameInfo implementation
426//===----------------------------------------------------------------------===//
427
428/// CreateFixedObject - Create a new object at a fixed location on the stack.
429/// All fixed objects should be created before other objects are created for
430/// efficiency. By default, fixed objects are immutable. This returns an
431/// index with a negative value.
432///
433int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
434                                        bool Immutable, bool isSS) {
435  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
436  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
437                                              isSS));
438  return -++NumFixedObjects;
439}
440
441
442BitVector
443MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
444  assert(MBB && "MBB must be valid");
445  const MachineFunction *MF = MBB->getParent();
446  assert(MF && "MBB must be part of a MachineFunction");
447  const TargetMachine &TM = MF->getTarget();
448  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
449  BitVector BV(TRI->getNumRegs());
450
451  // Before CSI is calculated, no registers are considered pristine. They can be
452  // freely used and PEI will make sure they are saved.
453  if (!isCalleeSavedInfoValid())
454    return BV;
455
456  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
457    BV.set(*CSR);
458
459  // The entry MBB always has all CSRs pristine.
460  if (MBB == &MF->front())
461    return BV;
462
463  // On other MBBs the saved CSRs are not pristine.
464  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
465  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
466         E = CSI.end(); I != E; ++I)
467    BV.reset(I->getReg());
468
469  return BV;
470}
471
472
473void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
474  if (Objects.empty()) return;
475
476  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
477  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
478
479  OS << "Frame Objects:\n";
480
481  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
482    const StackObject &SO = Objects[i];
483    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
484    if (SO.Size == ~0ULL) {
485      OS << "dead\n";
486      continue;
487    }
488    if (SO.Size == 0)
489      OS << "variable sized";
490    else
491      OS << "size=" << SO.Size;
492    OS << ", align=" << SO.Alignment;
493
494    if (i < NumFixedObjects)
495      OS << ", fixed";
496    if (i < NumFixedObjects || SO.SPOffset != -1) {
497      int64_t Off = SO.SPOffset - ValOffset;
498      OS << ", at location [SP";
499      if (Off > 0)
500        OS << "+" << Off;
501      else if (Off < 0)
502        OS << Off;
503      OS << "]";
504    }
505    OS << "\n";
506  }
507}
508
509void MachineFrameInfo::dump(const MachineFunction &MF) const {
510  print(MF, dbgs());
511}
512
513//===----------------------------------------------------------------------===//
514//  MachineJumpTableInfo implementation
515//===----------------------------------------------------------------------===//
516
517/// getEntrySize - Return the size of each entry in the jump table.
518unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
519  // The size of a jump table entry is 4 bytes unless the entry is just the
520  // address of a block, in which case it is the pointer size.
521  switch (getEntryKind()) {
522  case MachineJumpTableInfo::EK_BlockAddress:
523    return TD.getPointerSize();
524  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
525  case MachineJumpTableInfo::EK_LabelDifference32:
526  case MachineJumpTableInfo::EK_Custom32:
527    return 4;
528  case MachineJumpTableInfo::EK_Inline:
529    return 0;
530  }
531  assert(0 && "Unknown jump table encoding!");
532  return ~0;
533}
534
535/// getEntryAlignment - Return the alignment of each entry in the jump table.
536unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
537  // The alignment of a jump table entry is the alignment of int32 unless the
538  // entry is just the address of a block, in which case it is the pointer
539  // alignment.
540  switch (getEntryKind()) {
541  case MachineJumpTableInfo::EK_BlockAddress:
542    return TD.getPointerABIAlignment();
543  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
544  case MachineJumpTableInfo::EK_LabelDifference32:
545  case MachineJumpTableInfo::EK_Custom32:
546    return TD.getABIIntegerTypeAlignment(32);
547  case MachineJumpTableInfo::EK_Inline:
548    return 1;
549  }
550  assert(0 && "Unknown jump table encoding!");
551  return ~0;
552}
553
554/// createJumpTableIndex - Create a new jump table entry in the jump table info.
555///
556unsigned MachineJumpTableInfo::createJumpTableIndex(
557                               const std::vector<MachineBasicBlock*> &DestBBs) {
558  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
559  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
560  return JumpTables.size()-1;
561}
562
563/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
564/// the jump tables to branch to New instead.
565bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
566                                                  MachineBasicBlock *New) {
567  assert(Old != New && "Not making a change?");
568  bool MadeChange = false;
569  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
570    ReplaceMBBInJumpTable(i, Old, New);
571  return MadeChange;
572}
573
574/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
575/// the jump table to branch to New instead.
576bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
577                                                 MachineBasicBlock *Old,
578                                                 MachineBasicBlock *New) {
579  assert(Old != New && "Not making a change?");
580  bool MadeChange = false;
581  MachineJumpTableEntry &JTE = JumpTables[Idx];
582  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
583    if (JTE.MBBs[j] == Old) {
584      JTE.MBBs[j] = New;
585      MadeChange = true;
586    }
587  return MadeChange;
588}
589
590void MachineJumpTableInfo::print(raw_ostream &OS) const {
591  if (JumpTables.empty()) return;
592
593  OS << "Jump Tables:\n";
594
595  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
596    OS << "  jt#" << i << ": ";
597    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
598      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
599  }
600
601  OS << '\n';
602}
603
604void MachineJumpTableInfo::dump() const { print(dbgs()); }
605
606
607//===----------------------------------------------------------------------===//
608//  MachineConstantPool implementation
609//===----------------------------------------------------------------------===//
610
611const Type *MachineConstantPoolEntry::getType() const {
612  if (isMachineConstantPoolEntry())
613    return Val.MachineCPVal->getType();
614  return Val.ConstVal->getType();
615}
616
617
618unsigned MachineConstantPoolEntry::getRelocationInfo() const {
619  if (isMachineConstantPoolEntry())
620    return Val.MachineCPVal->getRelocationInfo();
621  return Val.ConstVal->getRelocationInfo();
622}
623
624MachineConstantPool::~MachineConstantPool() {
625  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
626    if (Constants[i].isMachineConstantPoolEntry())
627      delete Constants[i].Val.MachineCPVal;
628}
629
630/// CanShareConstantPoolEntry - Test whether the given two constants
631/// can be allocated the same constant pool entry.
632static bool CanShareConstantPoolEntry(Constant *A, Constant *B,
633                                      const TargetData *TD) {
634  // Handle the trivial case quickly.
635  if (A == B) return true;
636
637  // If they have the same type but weren't the same constant, quickly
638  // reject them.
639  if (A->getType() == B->getType()) return false;
640
641  // For now, only support constants with the same size.
642  if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
643    return false;
644
645  // If a floating-point value and an integer value have the same encoding,
646  // they can share a constant-pool entry.
647  if (ConstantFP *AFP = dyn_cast<ConstantFP>(A))
648    if (ConstantInt *BI = dyn_cast<ConstantInt>(B))
649      return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
650  if (ConstantFP *BFP = dyn_cast<ConstantFP>(B))
651    if (ConstantInt *AI = dyn_cast<ConstantInt>(A))
652      return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
653
654  // Two vectors can share an entry if each pair of corresponding
655  // elements could.
656  if (ConstantVector *AV = dyn_cast<ConstantVector>(A))
657    if (ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
658      if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
659        return false;
660      for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
661        if (!CanShareConstantPoolEntry(AV->getOperand(i),
662                                       BV->getOperand(i), TD))
663          return false;
664      return true;
665    }
666
667  // TODO: Handle other cases.
668
669  return false;
670}
671
672/// getConstantPoolIndex - Create a new entry in the constant pool or return
673/// an existing one.  User must specify the log2 of the minimum required
674/// alignment for the object.
675///
676unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
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  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
685    if (!Constants[i].isMachineConstantPoolEntry() &&
686        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
687      if ((unsigned)Constants[i].getAlignment() < Alignment)
688        Constants[i].Alignment = Alignment;
689      return i;
690    }
691
692  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
693  return Constants.size()-1;
694}
695
696unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
697                                                   unsigned Alignment) {
698  assert(Alignment && "Alignment must be specified!");
699  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
700
701  // Check to see if we already have this constant.
702  //
703  // FIXME, this could be made much more efficient for large constant pools.
704  int Idx = V->getExistingMachineCPValue(this, Alignment);
705  if (Idx != -1)
706    return (unsigned)Idx;
707
708  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
709  return Constants.size()-1;
710}
711
712void MachineConstantPool::print(raw_ostream &OS) const {
713  if (Constants.empty()) return;
714
715  OS << "Constant Pool:\n";
716  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
717    OS << "  cp#" << i << ": ";
718    if (Constants[i].isMachineConstantPoolEntry())
719      Constants[i].Val.MachineCPVal->print(OS);
720    else
721      OS << *(Value*)Constants[i].Val.ConstVal;
722    OS << ", align=" << Constants[i].getAlignment();
723    OS << "\n";
724  }
725}
726
727void MachineConstantPool::dump() const { print(dbgs()); }
728