MachineFunction.cpp revision 3574eca1b02600bac4e625297f4ecf745f4c4f32 
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/CodeGen/MachineFunction.h"
17#include "llvm/DebugInfo.h"
18#include "llvm/Function.h"
19#include "llvm/CodeGen/MachineConstantPool.h"
20#include "llvm/CodeGen/MachineFunctionPass.h"
21#include "llvm/CodeGen/MachineFrameInfo.h"
22#include "llvm/CodeGen/MachineInstr.h"
23#include "llvm/CodeGen/MachineJumpTableInfo.h"
24#include "llvm/CodeGen/MachineModuleInfo.h"
25#include "llvm/CodeGen/MachineRegisterInfo.h"
26#include "llvm/CodeGen/Passes.h"
27#include "llvm/MC/MCAsmInfo.h"
28#include "llvm/MC/MCContext.h"
29#include "llvm/Analysis/ConstantFolding.h"
30#include "llvm/Support/Debug.h"
31#include "llvm/DataLayout.h"
32#include "llvm/Target/TargetLowering.h"
33#include "llvm/Target/TargetMachine.h"
34#include "llvm/Target/TargetFrameLowering.h"
35#include "llvm/ADT/SmallString.h"
36#include "llvm/ADT/STLExtras.h"
37#include "llvm/Support/GraphWriter.h"
38#include "llvm/Support/raw_ostream.h"
39using namespace llvm;
40
41//===----------------------------------------------------------------------===//
42// MachineFunction implementation
43//===----------------------------------------------------------------------===//
44
45// Out of line virtual method.
46MachineFunctionInfo::~MachineFunctionInfo() {}
47
48void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
49  MBB->getParent()->DeleteMachineBasicBlock(MBB);
50}
51
52MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
53                                 unsigned FunctionNum, MachineModuleInfo &mmi,
54                                 GCModuleInfo* gmi)
55  : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
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.getFrameLowering());
62  if (Fn->getFnAttributes().hasStackAlignmentAttr())
63    FrameInfo->ensureMaxAlignment(Fn->getAttributes().
64                                  getFnAttributes().getStackAlignment());
65  ConstantPool = new (Allocator) MachineConstantPool(TM.getDataLayout());
66  Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
67  // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
68  if (!Fn->getFnAttributes().hasOptimizeForSizeAttr())
69    Alignment = std::max(Alignment,
70                         TM.getTargetLowering()->getPrefFunctionAlignment());
71  FunctionNumber = FunctionNum;
72  JumpTableInfo = 0;
73}
74
75MachineFunction::~MachineFunction() {
76  BasicBlocks.clear();
77  InstructionRecycler.clear(Allocator);
78  BasicBlockRecycler.clear(Allocator);
79  if (RegInfo) {
80    RegInfo->~MachineRegisterInfo();
81    Allocator.Deallocate(RegInfo);
82  }
83  if (MFInfo) {
84    MFInfo->~MachineFunctionInfo();
85    Allocator.Deallocate(MFInfo);
86  }
87
88  FrameInfo->~MachineFrameInfo();
89  Allocator.Deallocate(FrameInfo);
90
91  ConstantPool->~MachineConstantPool();
92  Allocator.Deallocate(ConstantPool);
93
94  if (JumpTableInfo) {
95    JumpTableInfo->~MachineJumpTableInfo();
96    Allocator.Deallocate(JumpTableInfo);
97  }
98}
99
100/// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
101/// does already exist, allocate one.
102MachineJumpTableInfo *MachineFunction::
103getOrCreateJumpTableInfo(unsigned EntryKind) {
104  if (JumpTableInfo) return JumpTableInfo;
105
106  JumpTableInfo = new (Allocator)
107    MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
108  return JumpTableInfo;
109}
110
111/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
112/// recomputes them.  This guarantees that the MBB numbers are sequential,
113/// dense, and match the ordering of the blocks within the function.  If a
114/// specific MachineBasicBlock is specified, only that block and those after
115/// it are renumbered.
116void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
117  if (empty()) { MBBNumbering.clear(); return; }
118  MachineFunction::iterator MBBI, E = end();
119  if (MBB == 0)
120    MBBI = begin();
121  else
122    MBBI = MBB;
123
124  // Figure out the block number this should have.
125  unsigned BlockNo = 0;
126  if (MBBI != begin())
127    BlockNo = prior(MBBI)->getNumber()+1;
128
129  for (; MBBI != E; ++MBBI, ++BlockNo) {
130    if (MBBI->getNumber() != (int)BlockNo) {
131      // Remove use of the old number.
132      if (MBBI->getNumber() != -1) {
133        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
134               "MBB number mismatch!");
135        MBBNumbering[MBBI->getNumber()] = 0;
136      }
137
138      // If BlockNo is already taken, set that block's number to -1.
139      if (MBBNumbering[BlockNo])
140        MBBNumbering[BlockNo]->setNumber(-1);
141
142      MBBNumbering[BlockNo] = MBBI;
143      MBBI->setNumber(BlockNo);
144    }
145  }
146
147  // Okay, all the blocks are renumbered.  If we have compactified the block
148  // numbering, shrink MBBNumbering now.
149  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
150  MBBNumbering.resize(BlockNo);
151}
152
153/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
154/// of `new MachineInstr'.
155///
156MachineInstr *
157MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
158                                    DebugLoc DL, bool NoImp) {
159  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
160    MachineInstr(MCID, DL, NoImp);
161}
162
163/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
164/// 'Orig' instruction, identical in all ways except the instruction
165/// has no parent, prev, or next.
166///
167MachineInstr *
168MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
169  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
170             MachineInstr(*this, *Orig);
171}
172
173/// DeleteMachineInstr - Delete the given MachineInstr.
174///
175void
176MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
177  MI->~MachineInstr();
178  InstructionRecycler.Deallocate(Allocator, MI);
179}
180
181/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
182/// instead of `new MachineBasicBlock'.
183///
184MachineBasicBlock *
185MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
186  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
187             MachineBasicBlock(*this, bb);
188}
189
190/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
191///
192void
193MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
194  assert(MBB->getParent() == this && "MBB parent mismatch!");
195  MBB->~MachineBasicBlock();
196  BasicBlockRecycler.Deallocate(Allocator, MBB);
197}
198
199MachineMemOperand *
200MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
201                                      uint64_t s, unsigned base_alignment,
202                                      const MDNode *TBAAInfo,
203                                      const MDNode *Ranges) {
204  return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
205                                           TBAAInfo, Ranges);
206}
207
208MachineMemOperand *
209MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
210                                      int64_t Offset, uint64_t Size) {
211  return new (Allocator)
212             MachineMemOperand(MachinePointerInfo(MMO->getValue(),
213                                                  MMO->getOffset()+Offset),
214                               MMO->getFlags(), Size,
215                               MMO->getBaseAlignment(), 0);
216}
217
218MachineInstr::mmo_iterator
219MachineFunction::allocateMemRefsArray(unsigned long Num) {
220  return Allocator.Allocate<MachineMemOperand *>(Num);
221}
222
223std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
224MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
225                                    MachineInstr::mmo_iterator End) {
226  // Count the number of load mem refs.
227  unsigned Num = 0;
228  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
229    if ((*I)->isLoad())
230      ++Num;
231
232  // Allocate a new array and populate it with the load information.
233  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
234  unsigned Index = 0;
235  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
236    if ((*I)->isLoad()) {
237      if (!(*I)->isStore())
238        // Reuse the MMO.
239        Result[Index] = *I;
240      else {
241        // Clone the MMO and unset the store flag.
242        MachineMemOperand *JustLoad =
243          getMachineMemOperand((*I)->getPointerInfo(),
244                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
245                               (*I)->getSize(), (*I)->getBaseAlignment(),
246                               (*I)->getTBAAInfo());
247        Result[Index] = JustLoad;
248      }
249      ++Index;
250    }
251  }
252  return std::make_pair(Result, Result + Num);
253}
254
255std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
256MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
257                                     MachineInstr::mmo_iterator End) {
258  // Count the number of load mem refs.
259  unsigned Num = 0;
260  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
261    if ((*I)->isStore())
262      ++Num;
263
264  // Allocate a new array and populate it with the store information.
265  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
266  unsigned Index = 0;
267  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
268    if ((*I)->isStore()) {
269      if (!(*I)->isLoad())
270        // Reuse the MMO.
271        Result[Index] = *I;
272      else {
273        // Clone the MMO and unset the load flag.
274        MachineMemOperand *JustStore =
275          getMachineMemOperand((*I)->getPointerInfo(),
276                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
277                               (*I)->getSize(), (*I)->getBaseAlignment(),
278                               (*I)->getTBAAInfo());
279        Result[Index] = JustStore;
280      }
281      ++Index;
282    }
283  }
284  return std::make_pair(Result, Result + Num);
285}
286
287#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
288void MachineFunction::dump() const {
289  print(dbgs());
290}
291#endif
292
293StringRef MachineFunction::getName() const {
294  assert(getFunction() && "No function!");
295  return getFunction()->getName();
296}
297
298void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
299  OS << "# Machine code for function " << getName() << ": ";
300  if (RegInfo) {
301    OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
302    if (!RegInfo->tracksLiveness())
303      OS << ", not tracking liveness";
304  }
305  OS << '\n';
306
307  // Print Frame Information
308  FrameInfo->print(*this, OS);
309
310  // Print JumpTable Information
311  if (JumpTableInfo)
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      OS << PrintReg(I->first, TRI);
324      if (I->second)
325        OS << " in " << PrintReg(I->second, TRI);
326      if (llvm::next(I) != E)
327        OS << ", ";
328    }
329    OS << '\n';
330  }
331  if (RegInfo && !RegInfo->liveout_empty()) {
332    OS << "Function Live Outs:";
333    for (MachineRegisterInfo::liveout_iterator
334         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
335      OS << ' ' << PrintReg(*I, TRI);
336    OS << '\n';
337  }
338
339  for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
340    OS << '\n';
341    BB->print(OS, Indexes);
342  }
343
344  OS << "\n# End machine code for function " << getName() << ".\n\n";
345}
346
347namespace llvm {
348  template<>
349  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
350
351  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
352
353    static std::string getGraphName(const MachineFunction *F) {
354      return "CFG for '" + F->getName().str() + "' function";
355    }
356
357    std::string getNodeLabel(const MachineBasicBlock *Node,
358                             const MachineFunction *Graph) {
359      std::string OutStr;
360      {
361        raw_string_ostream OSS(OutStr);
362
363        if (isSimple()) {
364          OSS << "BB#" << Node->getNumber();
365          if (const BasicBlock *BB = Node->getBasicBlock())
366            OSS << ": " << BB->getName();
367        } else
368          Node->print(OSS);
369      }
370
371      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
372
373      // Process string output to make it nicer...
374      for (unsigned i = 0; i != OutStr.length(); ++i)
375        if (OutStr[i] == '\n') {                            // Left justify
376          OutStr[i] = '\\';
377          OutStr.insert(OutStr.begin()+i+1, 'l');
378        }
379      return OutStr;
380    }
381  };
382}
383
384void MachineFunction::viewCFG() const
385{
386#ifndef NDEBUG
387  ViewGraph(this, "mf" + getName());
388#else
389  errs() << "MachineFunction::viewCFG is only available in debug builds on "
390         << "systems with Graphviz or gv!\n";
391#endif // NDEBUG
392}
393
394void MachineFunction::viewCFGOnly() const
395{
396#ifndef NDEBUG
397  ViewGraph(this, "mf" + getName(), true);
398#else
399  errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
400         << "systems with Graphviz or gv!\n";
401#endif // NDEBUG
402}
403
404/// addLiveIn - Add the specified physical register as a live-in value and
405/// create a corresponding virtual register for it.
406unsigned MachineFunction::addLiveIn(unsigned PReg,
407                                    const TargetRegisterClass *RC) {
408  MachineRegisterInfo &MRI = getRegInfo();
409  unsigned VReg = MRI.getLiveInVirtReg(PReg);
410  if (VReg) {
411    assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
412    return VReg;
413  }
414  VReg = MRI.createVirtualRegister(RC);
415  MRI.addLiveIn(PReg, VReg);
416  return VReg;
417}
418
419/// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
420/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
421/// normal 'L' label is returned.
422MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
423                                        bool isLinkerPrivate) const {
424  assert(JumpTableInfo && "No jump tables");
425  assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
426  const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
427
428  const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
429                                         MAI.getPrivateGlobalPrefix();
430  SmallString<60> Name;
431  raw_svector_ostream(Name)
432    << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
433  return Ctx.GetOrCreateSymbol(Name.str());
434}
435
436/// getPICBaseSymbol - Return a function-local symbol to represent the PIC
437/// base.
438MCSymbol *MachineFunction::getPICBaseSymbol() const {
439  const MCAsmInfo &MAI = *Target.getMCAsmInfo();
440  return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
441                               Twine(getFunctionNumber())+"$pb");
442}
443
444//===----------------------------------------------------------------------===//
445//  MachineFrameInfo implementation
446//===----------------------------------------------------------------------===//
447
448/// CreateFixedObject - Create a new object at a fixed location on the stack.
449/// All fixed objects should be created before other objects are created for
450/// efficiency. By default, fixed objects are immutable. This returns an
451/// index with a negative value.
452///
453int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
454                                        bool Immutable) {
455  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
456  // The alignment of the frame index can be determined from its offset from
457  // the incoming frame position.  If the frame object is at offset 32 and
458  // the stack is guaranteed to be 16-byte aligned, then we know that the
459  // object is 16-byte aligned.
460  unsigned StackAlign = TFI.getStackAlignment();
461  unsigned Align = MinAlign(SPOffset, StackAlign);
462  Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
463                                              /*isSS*/   false,
464                                              /*NeedSP*/ false,
465                                              /*Alloca*/ 0));
466  return -++NumFixedObjects;
467}
468
469
470BitVector
471MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
472  assert(MBB && "MBB must be valid");
473  const MachineFunction *MF = MBB->getParent();
474  assert(MF && "MBB must be part of a MachineFunction");
475  const TargetMachine &TM = MF->getTarget();
476  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
477  BitVector BV(TRI->getNumRegs());
478
479  // Before CSI is calculated, no registers are considered pristine. They can be
480  // freely used and PEI will make sure they are saved.
481  if (!isCalleeSavedInfoValid())
482    return BV;
483
484  for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
485    BV.set(*CSR);
486
487  // The entry MBB always has all CSRs pristine.
488  if (MBB == &MF->front())
489    return BV;
490
491  // On other MBBs the saved CSRs are not pristine.
492  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
493  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
494         E = CSI.end(); I != E; ++I)
495    BV.reset(I->getReg());
496
497  return BV;
498}
499
500
501void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
502  if (Objects.empty()) return;
503
504  const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
505  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
506
507  OS << "Frame Objects:\n";
508
509  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
510    const StackObject &SO = Objects[i];
511    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
512    if (SO.Size == ~0ULL) {
513      OS << "dead\n";
514      continue;
515    }
516    if (SO.Size == 0)
517      OS << "variable sized";
518    else
519      OS << "size=" << SO.Size;
520    OS << ", align=" << SO.Alignment;
521
522    if (i < NumFixedObjects)
523      OS << ", fixed";
524    if (i < NumFixedObjects || SO.SPOffset != -1) {
525      int64_t Off = SO.SPOffset - ValOffset;
526      OS << ", at location [SP";
527      if (Off > 0)
528        OS << "+" << Off;
529      else if (Off < 0)
530        OS << Off;
531      OS << "]";
532    }
533    OS << "\n";
534  }
535}
536
537#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
538void MachineFrameInfo::dump(const MachineFunction &MF) const {
539  print(MF, dbgs());
540}
541#endif
542
543//===----------------------------------------------------------------------===//
544//  MachineJumpTableInfo implementation
545//===----------------------------------------------------------------------===//
546
547/// getEntrySize - Return the size of each entry in the jump table.
548unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
549  // The size of a jump table entry is 4 bytes unless the entry is just the
550  // address of a block, in which case it is the pointer size.
551  switch (getEntryKind()) {
552  case MachineJumpTableInfo::EK_BlockAddress:
553    return TD.getPointerSize();
554  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
555    return 8;
556  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
557  case MachineJumpTableInfo::EK_LabelDifference32:
558  case MachineJumpTableInfo::EK_Custom32:
559    return 4;
560  case MachineJumpTableInfo::EK_Inline:
561    return 0;
562  }
563  llvm_unreachable("Unknown jump table encoding!");
564}
565
566/// getEntryAlignment - Return the alignment of each entry in the jump table.
567unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
568  // The alignment of a jump table entry is the alignment of int32 unless the
569  // entry is just the address of a block, in which case it is the pointer
570  // alignment.
571  switch (getEntryKind()) {
572  case MachineJumpTableInfo::EK_BlockAddress:
573    return TD.getPointerABIAlignment();
574  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
575    return TD.getABIIntegerTypeAlignment(64);
576  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
577  case MachineJumpTableInfo::EK_LabelDifference32:
578  case MachineJumpTableInfo::EK_Custom32:
579    return TD.getABIIntegerTypeAlignment(32);
580  case MachineJumpTableInfo::EK_Inline:
581    return 1;
582  }
583  llvm_unreachable("Unknown jump table encoding!");
584}
585
586/// createJumpTableIndex - Create a new jump table entry in the jump table info.
587///
588unsigned MachineJumpTableInfo::createJumpTableIndex(
589                               const std::vector<MachineBasicBlock*> &DestBBs) {
590  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
591  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
592  return JumpTables.size()-1;
593}
594
595/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
596/// the jump tables to branch to New instead.
597bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
598                                                  MachineBasicBlock *New) {
599  assert(Old != New && "Not making a change?");
600  bool MadeChange = false;
601  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
602    ReplaceMBBInJumpTable(i, Old, New);
603  return MadeChange;
604}
605
606/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
607/// the jump table to branch to New instead.
608bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
609                                                 MachineBasicBlock *Old,
610                                                 MachineBasicBlock *New) {
611  assert(Old != New && "Not making a change?");
612  bool MadeChange = false;
613  MachineJumpTableEntry &JTE = JumpTables[Idx];
614  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
615    if (JTE.MBBs[j] == Old) {
616      JTE.MBBs[j] = New;
617      MadeChange = true;
618    }
619  return MadeChange;
620}
621
622void MachineJumpTableInfo::print(raw_ostream &OS) const {
623  if (JumpTables.empty()) return;
624
625  OS << "Jump Tables:\n";
626
627  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
628    OS << "  jt#" << i << ": ";
629    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
630      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
631  }
632
633  OS << '\n';
634}
635
636#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
637void MachineJumpTableInfo::dump() const { print(dbgs()); }
638#endif
639
640
641//===----------------------------------------------------------------------===//
642//  MachineConstantPool implementation
643//===----------------------------------------------------------------------===//
644
645void MachineConstantPoolValue::anchor() { }
646
647Type *MachineConstantPoolEntry::getType() const {
648  if (isMachineConstantPoolEntry())
649    return Val.MachineCPVal->getType();
650  return Val.ConstVal->getType();
651}
652
653
654unsigned MachineConstantPoolEntry::getRelocationInfo() const {
655  if (isMachineConstantPoolEntry())
656    return Val.MachineCPVal->getRelocationInfo();
657  return Val.ConstVal->getRelocationInfo();
658}
659
660MachineConstantPool::~MachineConstantPool() {
661  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
662    if (Constants[i].isMachineConstantPoolEntry())
663      delete Constants[i].Val.MachineCPVal;
664  for (DenseSet<MachineConstantPoolValue*>::iterator I =
665       MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
666       I != E; ++I)
667    delete *I;
668}
669
670/// CanShareConstantPoolEntry - Test whether the given two constants
671/// can be allocated the same constant pool entry.
672static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
673                                      const DataLayout *TD) {
674  // Handle the trivial case quickly.
675  if (A == B) return true;
676
677  // If they have the same type but weren't the same constant, quickly
678  // reject them.
679  if (A->getType() == B->getType()) return false;
680
681  // We can't handle structs or arrays.
682  if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
683      isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
684    return false;
685
686  // For now, only support constants with the same size.
687  uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
688  if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
689      StoreSize > 128)
690    return false;
691
692  Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
693
694  // Try constant folding a bitcast of both instructions to an integer.  If we
695  // get two identical ConstantInt's, then we are good to share them.  We use
696  // the constant folding APIs to do this so that we get the benefit of
697  // DataLayout.
698  if (isa<PointerType>(A->getType()))
699    A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
700                                 const_cast<Constant*>(A), TD);
701  else if (A->getType() != IntTy)
702    A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
703                                 const_cast<Constant*>(A), TD);
704  if (isa<PointerType>(B->getType()))
705    B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
706                                 const_cast<Constant*>(B), TD);
707  else if (B->getType() != IntTy)
708    B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
709                                 const_cast<Constant*>(B), TD);
710
711  return A == B;
712}
713
714/// getConstantPoolIndex - Create a new entry in the constant pool or return
715/// an existing one.  User must specify the log2 of the minimum required
716/// alignment for the object.
717///
718unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
719                                                   unsigned Alignment) {
720  assert(Alignment && "Alignment must be specified!");
721  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
722
723  // Check to see if we already have this constant.
724  //
725  // FIXME, this could be made much more efficient for large constant pools.
726  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
727    if (!Constants[i].isMachineConstantPoolEntry() &&
728        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
729      if ((unsigned)Constants[i].getAlignment() < Alignment)
730        Constants[i].Alignment = Alignment;
731      return i;
732    }
733
734  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
735  return Constants.size()-1;
736}
737
738unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
739                                                   unsigned Alignment) {
740  assert(Alignment && "Alignment must be specified!");
741  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
742
743  // Check to see if we already have this constant.
744  //
745  // FIXME, this could be made much more efficient for large constant pools.
746  int Idx = V->getExistingMachineCPValue(this, Alignment);
747  if (Idx != -1) {
748    MachineCPVsSharingEntries.insert(V);
749    return (unsigned)Idx;
750  }
751
752  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
753  return Constants.size()-1;
754}
755
756void MachineConstantPool::print(raw_ostream &OS) const {
757  if (Constants.empty()) return;
758
759  OS << "Constant Pool:\n";
760  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
761    OS << "  cp#" << i << ": ";
762    if (Constants[i].isMachineConstantPoolEntry())
763      Constants[i].Val.MachineCPVal->print(OS);
764    else
765      OS << *(const Value*)Constants[i].Val.ConstVal;
766    OS << ", align=" << Constants[i].getAlignment();
767    OS << "\n";
768  }
769}
770
771#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
772void MachineConstantPool::dump() const { print(dbgs()); }
773#endif
774