MachineFunction.cpp revision 36c56d0353f1a9c4e878f509aff85a62e5087dd4 
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/MachineModuleInfo.h"
27#include "llvm/CodeGen/MachineRegisterInfo.h"
28#include "llvm/CodeGen/Passes.h"
29#include "llvm/MC/MCAsmInfo.h"
30#include "llvm/MC/MCContext.h"
31#include "llvm/Analysis/DebugInfo.h"
32#include "llvm/Support/Debug.h"
33#include "llvm/Target/TargetData.h"
34#include "llvm/Target/TargetLowering.h"
35#include "llvm/Target/TargetMachine.h"
36#include "llvm/Target/TargetFrameInfo.h"
37#include "llvm/ADT/SmallString.h"
38#include "llvm/ADT/STLExtras.h"
39#include "llvm/Support/GraphWriter.h"
40#include "llvm/Support/raw_ostream.h"
41using namespace llvm;
42
43//===----------------------------------------------------------------------===//
44// MachineFunction implementation
45//===----------------------------------------------------------------------===//
46
47// Out of line virtual method.
48MachineFunctionInfo::~MachineFunctionInfo() {}
49
50void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
51  MBB->getParent()->DeleteMachineBasicBlock(MBB);
52}
53
54MachineFunction::MachineFunction(Function *F, const TargetMachine &TM,
55                                 unsigned FunctionNum, MachineModuleInfo &mmi)
56  : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi) {
57  if (TM.getRegisterInfo())
58    RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
59  else
60    RegInfo = 0;
61  MFInfo = 0;
62  FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameInfo());
63  if (Fn->hasFnAttr(Attribute::StackAlignment))
64    FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
65        Fn->getAttributes().getFnAttributes()));
66  ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
67  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
68  FunctionNumber = FunctionNum;
69  JumpTableInfo = 0;
70}
71
72MachineFunction::~MachineFunction() {
73  BasicBlocks.clear();
74  InstructionRecycler.clear(Allocator);
75  BasicBlockRecycler.clear(Allocator);
76  if (RegInfo) {
77    RegInfo->~MachineRegisterInfo();
78    Allocator.Deallocate(RegInfo);
79  }
80  if (MFInfo) {
81    MFInfo->~MachineFunctionInfo();
82    Allocator.Deallocate(MFInfo);
83  }
84  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
85  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
86
87  if (JumpTableInfo) {
88    JumpTableInfo->~MachineJumpTableInfo();
89    Allocator.Deallocate(JumpTableInfo);
90  }
91}
92
93/// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
94/// does already exist, allocate one.
95MachineJumpTableInfo *MachineFunction::
96getOrCreateJumpTableInfo(unsigned EntryKind) {
97  if (JumpTableInfo) return JumpTableInfo;
98
99  JumpTableInfo = new (Allocator)
100    MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
101  return JumpTableInfo;
102}
103
104/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
105/// recomputes them.  This guarantees that the MBB numbers are sequential,
106/// dense, and match the ordering of the blocks within the function.  If a
107/// specific MachineBasicBlock is specified, only that block and those after
108/// it are renumbered.
109void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
110  if (empty()) { MBBNumbering.clear(); return; }
111  MachineFunction::iterator MBBI, E = end();
112  if (MBB == 0)
113    MBBI = begin();
114  else
115    MBBI = MBB;
116
117  // Figure out the block number this should have.
118  unsigned BlockNo = 0;
119  if (MBBI != begin())
120    BlockNo = prior(MBBI)->getNumber()+1;
121
122  for (; MBBI != E; ++MBBI, ++BlockNo) {
123    if (MBBI->getNumber() != (int)BlockNo) {
124      // Remove use of the old number.
125      if (MBBI->getNumber() != -1) {
126        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
127               "MBB number mismatch!");
128        MBBNumbering[MBBI->getNumber()] = 0;
129      }
130
131      // If BlockNo is already taken, set that block's number to -1.
132      if (MBBNumbering[BlockNo])
133        MBBNumbering[BlockNo]->setNumber(-1);
134
135      MBBNumbering[BlockNo] = MBBI;
136      MBBI->setNumber(BlockNo);
137    }
138  }
139
140  // Okay, all the blocks are renumbered.  If we have compactified the block
141  // numbering, shrink MBBNumbering now.
142  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
143  MBBNumbering.resize(BlockNo);
144}
145
146/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
147/// of `new MachineInstr'.
148///
149MachineInstr *
150MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
151                                    DebugLoc DL, bool NoImp) {
152  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
153    MachineInstr(TID, DL, NoImp);
154}
155
156/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
157/// 'Orig' instruction, identical in all ways except the instruction
158/// has no parent, prev, or next.
159///
160MachineInstr *
161MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
162  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
163             MachineInstr(*this, *Orig);
164}
165
166/// DeleteMachineInstr - Delete the given MachineInstr.
167///
168void
169MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
170  MI->~MachineInstr();
171  InstructionRecycler.Deallocate(Allocator, MI);
172}
173
174/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
175/// instead of `new MachineBasicBlock'.
176///
177MachineBasicBlock *
178MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
179  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
180             MachineBasicBlock(*this, bb);
181}
182
183/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
184///
185void
186MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
187  assert(MBB->getParent() == this && "MBB parent mismatch!");
188  MBB->~MachineBasicBlock();
189  BasicBlockRecycler.Deallocate(Allocator, MBB);
190}
191
192MachineMemOperand *
193MachineFunction::getMachineMemOperand(const Value *v, unsigned f,
194                                      int64_t o, uint64_t s,
195                                      unsigned base_alignment) {
196  return new (Allocator) MachineMemOperand(v, f, o, s, base_alignment);
197}
198
199MachineMemOperand *
200MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
201                                      int64_t Offset, uint64_t Size) {
202  return new (Allocator)
203             MachineMemOperand(MMO->getValue(), MMO->getFlags(),
204                               int64_t(uint64_t(MMO->getOffset()) +
205                                       uint64_t(Offset)),
206                               Size, MMO->getBaseAlignment());
207}
208
209MachineInstr::mmo_iterator
210MachineFunction::allocateMemRefsArray(unsigned long Num) {
211  return Allocator.Allocate<MachineMemOperand *>(Num);
212}
213
214std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
215MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
216                                    MachineInstr::mmo_iterator End) {
217  // Count the number of load mem refs.
218  unsigned Num = 0;
219  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
220    if ((*I)->isLoad())
221      ++Num;
222
223  // Allocate a new array and populate it with the load information.
224  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
225  unsigned Index = 0;
226  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
227    if ((*I)->isLoad()) {
228      if (!(*I)->isStore())
229        // Reuse the MMO.
230        Result[Index] = *I;
231      else {
232        // Clone the MMO and unset the store flag.
233        MachineMemOperand *JustLoad =
234          getMachineMemOperand((*I)->getValue(),
235                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
236                               (*I)->getOffset(), (*I)->getSize(),
237                               (*I)->getBaseAlignment());
238        Result[Index] = JustLoad;
239      }
240      ++Index;
241    }
242  }
243  return std::make_pair(Result, Result + Num);
244}
245
246std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
247MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
248                                     MachineInstr::mmo_iterator End) {
249  // Count the number of load mem refs.
250  unsigned Num = 0;
251  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
252    if ((*I)->isStore())
253      ++Num;
254
255  // Allocate a new array and populate it with the store information.
256  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
257  unsigned Index = 0;
258  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
259    if ((*I)->isStore()) {
260      if (!(*I)->isLoad())
261        // Reuse the MMO.
262        Result[Index] = *I;
263      else {
264        // Clone the MMO and unset the load flag.
265        MachineMemOperand *JustStore =
266          getMachineMemOperand((*I)->getValue(),
267                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
268                               (*I)->getOffset(), (*I)->getSize(),
269                               (*I)->getBaseAlignment());
270        Result[Index] = JustStore;
271      }
272      ++Index;
273    }
274  }
275  return std::make_pair(Result, Result + Num);
276}
277
278void MachineFunction::dump() const {
279  print(dbgs());
280}
281
282void MachineFunction::print(raw_ostream &OS) const {
283  OS << "# Machine code for function " << Fn->getName() << ":\n";
284
285  // Print Frame Information
286  FrameInfo->print(*this, OS);
287
288  // Print JumpTable Information
289  if (JumpTableInfo)
290    JumpTableInfo->print(OS);
291
292  // Print Constant Pool
293  ConstantPool->print(OS);
294
295  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
296
297  if (RegInfo && !RegInfo->livein_empty()) {
298    OS << "Function Live Ins: ";
299    for (MachineRegisterInfo::livein_iterator
300         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
301      if (TRI)
302        OS << "%" << TRI->getName(I->first);
303      else
304        OS << " %physreg" << I->first;
305
306      if (I->second)
307        OS << " in reg%" << I->second;
308
309      if (llvm::next(I) != E)
310        OS << ", ";
311    }
312    OS << '\n';
313  }
314  if (RegInfo && !RegInfo->liveout_empty()) {
315    OS << "Function Live Outs: ";
316    for (MachineRegisterInfo::liveout_iterator
317         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I){
318      if (TRI)
319        OS << '%' << TRI->getName(*I);
320      else
321        OS << "%physreg" << *I;
322
323      if (llvm::next(I) != E)
324        OS << " ";
325    }
326    OS << '\n';
327  }
328
329  for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
330    OS << '\n';
331    BB->print(OS);
332  }
333
334  OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
335}
336
337namespace llvm {
338  template<>
339  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
340
341  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
342
343    static std::string getGraphName(const MachineFunction *F) {
344      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
345    }
346
347    std::string getNodeLabel(const MachineBasicBlock *Node,
348                             const MachineFunction *Graph) {
349      if (isSimple () && Node->getBasicBlock() &&
350          !Node->getBasicBlock()->getName().empty())
351        return Node->getBasicBlock()->getNameStr() + ":";
352
353      std::string OutStr;
354      {
355        raw_string_ostream OSS(OutStr);
356
357        if (isSimple())
358          OSS << Node->getNumber() << ':';
359        else
360          Node->print(OSS);
361      }
362
363      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
364
365      // Process string output to make it nicer...
366      for (unsigned i = 0; i != OutStr.length(); ++i)
367        if (OutStr[i] == '\n') {                            // Left justify
368          OutStr[i] = '\\';
369          OutStr.insert(OutStr.begin()+i+1, 'l');
370        }
371      return OutStr;
372    }
373  };
374}
375
376void MachineFunction::viewCFG() const
377{
378#ifndef NDEBUG
379  ViewGraph(this, "mf" + getFunction()->getNameStr());
380#else
381  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
382         << "systems with Graphviz or gv!\n";
383#endif // NDEBUG
384}
385
386void MachineFunction::viewCFGOnly() const
387{
388#ifndef NDEBUG
389  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
390#else
391  errs() << "SelectionDAG::viewGraph is only available in debug builds on "
392         << "systems with Graphviz or gv!\n";
393#endif // NDEBUG
394}
395
396/// addLiveIn - Add the specified physical register as a live-in value and
397/// create a corresponding virtual register for it.
398unsigned MachineFunction::addLiveIn(unsigned PReg,
399                                    const TargetRegisterClass *RC) {
400  assert(RC->contains(PReg) && "Not the correct regclass!");
401  unsigned VReg = getRegInfo().createVirtualRegister(RC);
402  getRegInfo().addLiveIn(PReg, VReg);
403  return VReg;
404}
405
406/// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
407/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
408/// normal 'L' label is returned.
409MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
410                                        bool isLinkerPrivate) const {
411  assert(JumpTableInfo && "No jump tables");
412
413  assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
414  const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
415
416  const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
417                                         MAI.getPrivateGlobalPrefix();
418  SmallString<60> Name;
419  raw_svector_ostream(Name)
420    << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
421  return Ctx.GetOrCreateSymbol(Name.str());
422}
423
424
425//===----------------------------------------------------------------------===//
426//  MachineFrameInfo implementation
427//===----------------------------------------------------------------------===//
428
429/// CreateFixedObject - Create a new object at a fixed location on the stack.
430/// All fixed objects should be created before other objects are created for
431/// efficiency. By default, fixed objects are immutable. This returns an
432/// index with a negative value.
433///
434int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
435                                        bool Immutable, bool isSS) {
436  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
437  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
438                                              isSS));
439  return -++NumFixedObjects;
440}
441
442
443BitVector
444MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
445  assert(MBB && "MBB must be valid");
446  const MachineFunction *MF = MBB->getParent();
447  assert(MF && "MBB must be part of a MachineFunction");
448  const TargetMachine &TM = MF->getTarget();
449  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
450  BitVector BV(TRI->getNumRegs());
451
452  // Before CSI is calculated, no registers are considered pristine. They can be
453  // freely used and PEI will make sure they are saved.
454  if (!isCalleeSavedInfoValid())
455    return BV;
456
457  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
458    BV.set(*CSR);
459
460  // The entry MBB always has all CSRs pristine.
461  if (MBB == &MF->front())
462    return BV;
463
464  // On other MBBs the saved CSRs are not pristine.
465  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
466  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
467         E = CSI.end(); I != E; ++I)
468    BV.reset(I->getReg());
469
470  return BV;
471}
472
473
474void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
475  if (Objects.empty()) return;
476
477  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
478  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
479
480  OS << "Frame Objects:\n";
481
482  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
483    const StackObject &SO = Objects[i];
484    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
485    if (SO.Size == ~0ULL) {
486      OS << "dead\n";
487      continue;
488    }
489    if (SO.Size == 0)
490      OS << "variable sized";
491    else
492      OS << "size=" << SO.Size;
493    OS << ", align=" << SO.Alignment;
494
495    if (i < NumFixedObjects)
496      OS << ", fixed";
497    if (i < NumFixedObjects || SO.SPOffset != -1) {
498      int64_t Off = SO.SPOffset - ValOffset;
499      OS << ", at location [SP";
500      if (Off > 0)
501        OS << "+" << Off;
502      else if (Off < 0)
503        OS << Off;
504      OS << "]";
505    }
506    OS << "\n";
507  }
508}
509
510void MachineFrameInfo::dump(const MachineFunction &MF) const {
511  print(MF, dbgs());
512}
513
514//===----------------------------------------------------------------------===//
515//  MachineJumpTableInfo implementation
516//===----------------------------------------------------------------------===//
517
518/// getEntrySize - Return the size of each entry in the jump table.
519unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
520  // The size of a jump table entry is 4 bytes unless the entry is just the
521  // address of a block, in which case it is the pointer size.
522  switch (getEntryKind()) {
523  case MachineJumpTableInfo::EK_BlockAddress:
524    return TD.getPointerSize();
525  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
526  case MachineJumpTableInfo::EK_LabelDifference32:
527  case MachineJumpTableInfo::EK_Custom32:
528    return 4;
529  case MachineJumpTableInfo::EK_Inline:
530    return 0;
531  }
532  assert(0 && "Unknown jump table encoding!");
533  return ~0;
534}
535
536/// getEntryAlignment - Return the alignment of each entry in the jump table.
537unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
538  // The alignment of a jump table entry is the alignment of int32 unless the
539  // entry is just the address of a block, in which case it is the pointer
540  // alignment.
541  switch (getEntryKind()) {
542  case MachineJumpTableInfo::EK_BlockAddress:
543    return TD.getPointerABIAlignment();
544  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
545  case MachineJumpTableInfo::EK_LabelDifference32:
546  case MachineJumpTableInfo::EK_Custom32:
547    return TD.getABIIntegerTypeAlignment(32);
548  case MachineJumpTableInfo::EK_Inline:
549    return 1;
550  }
551  assert(0 && "Unknown jump table encoding!");
552  return ~0;
553}
554
555/// createJumpTableIndex - Create a new jump table entry in the jump table info.
556///
557unsigned MachineJumpTableInfo::createJumpTableIndex(
558                               const std::vector<MachineBasicBlock*> &DestBBs) {
559  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
560  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
561  return JumpTables.size()-1;
562}
563
564/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
565/// the jump tables to branch to New instead.
566bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
567                                                  MachineBasicBlock *New) {
568  assert(Old != New && "Not making a change?");
569  bool MadeChange = false;
570  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
571    ReplaceMBBInJumpTable(i, Old, New);
572  return MadeChange;
573}
574
575/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
576/// the jump table to branch to New instead.
577bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
578                                                 MachineBasicBlock *Old,
579                                                 MachineBasicBlock *New) {
580  assert(Old != New && "Not making a change?");
581  bool MadeChange = false;
582  MachineJumpTableEntry &JTE = JumpTables[Idx];
583  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
584    if (JTE.MBBs[j] == Old) {
585      JTE.MBBs[j] = New;
586      MadeChange = true;
587    }
588  return MadeChange;
589}
590
591void MachineJumpTableInfo::print(raw_ostream &OS) const {
592  if (JumpTables.empty()) return;
593
594  OS << "Jump Tables:\n";
595
596  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
597    OS << "  jt#" << i << ": ";
598    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
599      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
600  }
601
602  OS << '\n';
603}
604
605void MachineJumpTableInfo::dump() const { print(dbgs()); }
606
607
608//===----------------------------------------------------------------------===//
609//  MachineConstantPool implementation
610//===----------------------------------------------------------------------===//
611
612const Type *MachineConstantPoolEntry::getType() const {
613  if (isMachineConstantPoolEntry())
614    return Val.MachineCPVal->getType();
615  return Val.ConstVal->getType();
616}
617
618
619unsigned MachineConstantPoolEntry::getRelocationInfo() const {
620  if (isMachineConstantPoolEntry())
621    return Val.MachineCPVal->getRelocationInfo();
622  return Val.ConstVal->getRelocationInfo();
623}
624
625MachineConstantPool::~MachineConstantPool() {
626  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
627    if (Constants[i].isMachineConstantPoolEntry())
628      delete Constants[i].Val.MachineCPVal;
629}
630
631/// CanShareConstantPoolEntry - Test whether the given two constants
632/// can be allocated the same constant pool entry.
633static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
634                                      const TargetData *TD) {
635  // Handle the trivial case quickly.
636  if (A == B) return true;
637
638  // If they have the same type but weren't the same constant, quickly
639  // reject them.
640  if (A->getType() == B->getType()) return false;
641
642  // For now, only support constants with the same size.
643  if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
644    return false;
645
646  // If a floating-point value and an integer value have the same encoding,
647  // they can share a constant-pool entry.
648  if (const ConstantFP *AFP = dyn_cast<ConstantFP>(A))
649    if (const ConstantInt *BI = dyn_cast<ConstantInt>(B))
650      return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
651  if (const ConstantFP *BFP = dyn_cast<ConstantFP>(B))
652    if (const ConstantInt *AI = dyn_cast<ConstantInt>(A))
653      return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
654
655  // Two vectors can share an entry if each pair of corresponding
656  // elements could.
657  if (const ConstantVector *AV = dyn_cast<ConstantVector>(A))
658    if (const ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
659      if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
660        return false;
661      for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
662        if (!CanShareConstantPoolEntry(AV->getOperand(i),
663                                       BV->getOperand(i), TD))
664          return false;
665      return true;
666    }
667
668  // TODO: Handle other cases.
669
670  return false;
671}
672
673/// getConstantPoolIndex - Create a new entry in the constant pool or return
674/// an existing one.  User must specify the log2 of the minimum required
675/// alignment for the object.
676///
677unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
678                                                   unsigned Alignment) {
679  assert(Alignment && "Alignment must be specified!");
680  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
681
682  // Check to see if we already have this constant.
683  //
684  // FIXME, this could be made much more efficient for large constant pools.
685  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
686    if (!Constants[i].isMachineConstantPoolEntry() &&
687        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
688      if ((unsigned)Constants[i].getAlignment() < Alignment)
689        Constants[i].Alignment = Alignment;
690      return i;
691    }
692
693  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
694  return Constants.size()-1;
695}
696
697unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
698                                                   unsigned Alignment) {
699  assert(Alignment && "Alignment must be specified!");
700  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
701
702  // Check to see if we already have this constant.
703  //
704  // FIXME, this could be made much more efficient for large constant pools.
705  int Idx = V->getExistingMachineCPValue(this, Alignment);
706  if (Idx != -1)
707    return (unsigned)Idx;
708
709  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
710  return Constants.size()-1;
711}
712
713void MachineConstantPool::print(raw_ostream &OS) const {
714  if (Constants.empty()) return;
715
716  OS << "Constant Pool:\n";
717  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
718    OS << "  cp#" << i << ": ";
719    if (Constants[i].isMachineConstantPoolEntry())
720      Constants[i].Val.MachineCPVal->print(OS);
721    else
722      OS << *(Value*)Constants[i].Val.ConstVal;
723    OS << ", align=" << Constants[i].getAlignment();
724    OS << "\n";
725  }
726}
727
728void MachineConstantPool::dump() const { print(dbgs()); }
729