MachineFunction.cpp revision 8ef3acba00c9c42d450fa52c7d3faebce1e507dd 
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/// getDILocation - Get the DILocation for a given DebugLoc object.
406DILocation MachineFunction::getDILocation(DebugLoc DL) const {
407  unsigned Idx = DL.getIndex();
408  assert(Idx < DebugLocInfo.DebugLocations.size() &&
409         "Invalid index into debug locations!");
410  return DILocation(DebugLocInfo.DebugLocations[Idx]);
411}
412
413
414/// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
415/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
416/// normal 'L' label is returned.
417MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
418                                        bool isLinkerPrivate) const {
419  assert(JumpTableInfo && "No jump tables");
420
421  assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
422  const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
423
424  const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
425                                         MAI.getPrivateGlobalPrefix();
426  SmallString<60> Name;
427  raw_svector_ostream(Name)
428    << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
429  return Ctx.GetOrCreateSymbol(Name.str());
430}
431
432
433//===----------------------------------------------------------------------===//
434//  MachineFrameInfo implementation
435//===----------------------------------------------------------------------===//
436
437/// CreateFixedObject - Create a new object at a fixed location on the stack.
438/// All fixed objects should be created before other objects are created for
439/// efficiency. By default, fixed objects are immutable. This returns an
440/// index with a negative value.
441///
442int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
443                                        bool Immutable, bool isSS) {
444  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
445  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
446                                              isSS));
447  return -++NumFixedObjects;
448}
449
450
451BitVector
452MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
453  assert(MBB && "MBB must be valid");
454  const MachineFunction *MF = MBB->getParent();
455  assert(MF && "MBB must be part of a MachineFunction");
456  const TargetMachine &TM = MF->getTarget();
457  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
458  BitVector BV(TRI->getNumRegs());
459
460  // Before CSI is calculated, no registers are considered pristine. They can be
461  // freely used and PEI will make sure they are saved.
462  if (!isCalleeSavedInfoValid())
463    return BV;
464
465  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
466    BV.set(*CSR);
467
468  // The entry MBB always has all CSRs pristine.
469  if (MBB == &MF->front())
470    return BV;
471
472  // On other MBBs the saved CSRs are not pristine.
473  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
474  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
475         E = CSI.end(); I != E; ++I)
476    BV.reset(I->getReg());
477
478  return BV;
479}
480
481
482void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
483  if (Objects.empty()) return;
484
485  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
486  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
487
488  OS << "Frame Objects:\n";
489
490  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
491    const StackObject &SO = Objects[i];
492    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
493    if (SO.Size == ~0ULL) {
494      OS << "dead\n";
495      continue;
496    }
497    if (SO.Size == 0)
498      OS << "variable sized";
499    else
500      OS << "size=" << SO.Size;
501    OS << ", align=" << SO.Alignment;
502
503    if (i < NumFixedObjects)
504      OS << ", fixed";
505    if (i < NumFixedObjects || SO.SPOffset != -1) {
506      int64_t Off = SO.SPOffset - ValOffset;
507      OS << ", at location [SP";
508      if (Off > 0)
509        OS << "+" << Off;
510      else if (Off < 0)
511        OS << Off;
512      OS << "]";
513    }
514    OS << "\n";
515  }
516}
517
518void MachineFrameInfo::dump(const MachineFunction &MF) const {
519  print(MF, dbgs());
520}
521
522//===----------------------------------------------------------------------===//
523//  MachineJumpTableInfo implementation
524//===----------------------------------------------------------------------===//
525
526/// getEntrySize - Return the size of each entry in the jump table.
527unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
528  // The size of a jump table entry is 4 bytes unless the entry is just the
529  // address of a block, in which case it is the pointer size.
530  switch (getEntryKind()) {
531  case MachineJumpTableInfo::EK_BlockAddress:
532    return TD.getPointerSize();
533  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
534  case MachineJumpTableInfo::EK_LabelDifference32:
535  case MachineJumpTableInfo::EK_Custom32:
536    return 4;
537  case MachineJumpTableInfo::EK_Inline:
538    return 0;
539  }
540  assert(0 && "Unknown jump table encoding!");
541  return ~0;
542}
543
544/// getEntryAlignment - Return the alignment of each entry in the jump table.
545unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
546  // The alignment of a jump table entry is the alignment of int32 unless the
547  // entry is just the address of a block, in which case it is the pointer
548  // alignment.
549  switch (getEntryKind()) {
550  case MachineJumpTableInfo::EK_BlockAddress:
551    return TD.getPointerABIAlignment();
552  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
553  case MachineJumpTableInfo::EK_LabelDifference32:
554  case MachineJumpTableInfo::EK_Custom32:
555    return TD.getABIIntegerTypeAlignment(32);
556  case MachineJumpTableInfo::EK_Inline:
557    return 1;
558  }
559  assert(0 && "Unknown jump table encoding!");
560  return ~0;
561}
562
563/// createJumpTableIndex - Create a new jump table entry in the jump table info.
564///
565unsigned MachineJumpTableInfo::createJumpTableIndex(
566                               const std::vector<MachineBasicBlock*> &DestBBs) {
567  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
568  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
569  return JumpTables.size()-1;
570}
571
572/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
573/// the jump tables to branch to New instead.
574bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
575                                                  MachineBasicBlock *New) {
576  assert(Old != New && "Not making a change?");
577  bool MadeChange = false;
578  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
579    ReplaceMBBInJumpTable(i, Old, New);
580  return MadeChange;
581}
582
583/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
584/// the jump table to branch to New instead.
585bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
586                                                 MachineBasicBlock *Old,
587                                                 MachineBasicBlock *New) {
588  assert(Old != New && "Not making a change?");
589  bool MadeChange = false;
590  MachineJumpTableEntry &JTE = JumpTables[Idx];
591  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
592    if (JTE.MBBs[j] == Old) {
593      JTE.MBBs[j] = New;
594      MadeChange = true;
595    }
596  return MadeChange;
597}
598
599void MachineJumpTableInfo::print(raw_ostream &OS) const {
600  if (JumpTables.empty()) return;
601
602  OS << "Jump Tables:\n";
603
604  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
605    OS << "  jt#" << i << ": ";
606    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
607      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
608  }
609
610  OS << '\n';
611}
612
613void MachineJumpTableInfo::dump() const { print(dbgs()); }
614
615
616//===----------------------------------------------------------------------===//
617//  MachineConstantPool implementation
618//===----------------------------------------------------------------------===//
619
620const Type *MachineConstantPoolEntry::getType() const {
621  if (isMachineConstantPoolEntry())
622    return Val.MachineCPVal->getType();
623  return Val.ConstVal->getType();
624}
625
626
627unsigned MachineConstantPoolEntry::getRelocationInfo() const {
628  if (isMachineConstantPoolEntry())
629    return Val.MachineCPVal->getRelocationInfo();
630  return Val.ConstVal->getRelocationInfo();
631}
632
633MachineConstantPool::~MachineConstantPool() {
634  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
635    if (Constants[i].isMachineConstantPoolEntry())
636      delete Constants[i].Val.MachineCPVal;
637}
638
639/// CanShareConstantPoolEntry - Test whether the given two constants
640/// can be allocated the same constant pool entry.
641static bool CanShareConstantPoolEntry(Constant *A, Constant *B,
642                                      const TargetData *TD) {
643  // Handle the trivial case quickly.
644  if (A == B) return true;
645
646  // If they have the same type but weren't the same constant, quickly
647  // reject them.
648  if (A->getType() == B->getType()) return false;
649
650  // For now, only support constants with the same size.
651  if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
652    return false;
653
654  // If a floating-point value and an integer value have the same encoding,
655  // they can share a constant-pool entry.
656  if (ConstantFP *AFP = dyn_cast<ConstantFP>(A))
657    if (ConstantInt *BI = dyn_cast<ConstantInt>(B))
658      return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
659  if (ConstantFP *BFP = dyn_cast<ConstantFP>(B))
660    if (ConstantInt *AI = dyn_cast<ConstantInt>(A))
661      return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
662
663  // Two vectors can share an entry if each pair of corresponding
664  // elements could.
665  if (ConstantVector *AV = dyn_cast<ConstantVector>(A))
666    if (ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
667      if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
668        return false;
669      for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
670        if (!CanShareConstantPoolEntry(AV->getOperand(i),
671                                       BV->getOperand(i), TD))
672          return false;
673      return true;
674    }
675
676  // TODO: Handle other cases.
677
678  return false;
679}
680
681/// getConstantPoolIndex - Create a new entry in the constant pool or return
682/// an existing one.  User must specify the log2 of the minimum required
683/// alignment for the object.
684///
685unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
686                                                   unsigned Alignment) {
687  assert(Alignment && "Alignment must be specified!");
688  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
689
690  // Check to see if we already have this constant.
691  //
692  // FIXME, this could be made much more efficient for large constant pools.
693  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
694    if (!Constants[i].isMachineConstantPoolEntry() &&
695        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
696      if ((unsigned)Constants[i].getAlignment() < Alignment)
697        Constants[i].Alignment = Alignment;
698      return i;
699    }
700
701  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
702  return Constants.size()-1;
703}
704
705unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
706                                                   unsigned Alignment) {
707  assert(Alignment && "Alignment must be specified!");
708  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
709
710  // Check to see if we already have this constant.
711  //
712  // FIXME, this could be made much more efficient for large constant pools.
713  int Idx = V->getExistingMachineCPValue(this, Alignment);
714  if (Idx != -1)
715    return (unsigned)Idx;
716
717  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
718  return Constants.size()-1;
719}
720
721void MachineConstantPool::print(raw_ostream &OS) const {
722  if (Constants.empty()) return;
723
724  OS << "Constant Pool:\n";
725  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
726    OS << "  cp#" << i << ": ";
727    if (Constants[i].isMachineConstantPoolEntry())
728      Constants[i].Val.MachineCPVal->print(OS);
729    else
730      OS << *(Value*)Constants[i].Val.ConstVal;
731    OS << ", align=" << Constants[i].getAlignment();
732    OS << "\n";
733  }
734}
735
736void MachineConstantPool::dump() const { print(dbgs()); }
737