MachineFunction.cpp revision 59324297650c12a8dccf1a7ad650a9e895fdc17e 
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/Target/TargetData.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->hasFnAttr(Attribute::StackAlignment))
63    FrameInfo->ensureMaxAlignment(Attribute::getStackAlignmentFromAttrs(
64        Fn->getAttributes().getFnAttributes()));
65  ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
66  Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
67  // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
68  if (!Fn->hasFnAttr(Attribute::OptimizeForSize))
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
287void MachineFunction::dump() const {
288  print(dbgs());
289}
290
291StringRef MachineFunction::getName() const {
292  assert(getFunction() && "No function!");
293  return getFunction()->getName();
294}
295
296void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
297  OS << "# Machine code for function " << getName() << ": ";
298  if (RegInfo) {
299    OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
300    if (!RegInfo->tracksLiveness())
301      OS << ", not tracking liveness";
302  }
303  OS << '\n';
304
305  // Print Frame Information
306  FrameInfo->print(*this, OS);
307
308  // Print JumpTable Information
309  if (JumpTableInfo)
310    JumpTableInfo->print(OS);
311
312  // Print Constant Pool
313  ConstantPool->print(OS);
314
315  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
316
317  if (RegInfo && !RegInfo->livein_empty()) {
318    OS << "Function Live Ins: ";
319    for (MachineRegisterInfo::livein_iterator
320         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
321      OS << PrintReg(I->first, TRI);
322      if (I->second)
323        OS << " in " << PrintReg(I->second, TRI);
324      if (llvm::next(I) != E)
325        OS << ", ";
326    }
327    OS << '\n';
328  }
329  if (RegInfo && !RegInfo->liveout_empty()) {
330    OS << "Function Live Outs:";
331    for (MachineRegisterInfo::liveout_iterator
332         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
333      OS << ' ' << PrintReg(*I, TRI);
334    OS << '\n';
335  }
336
337  for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
338    OS << '\n';
339    BB->print(OS, Indexes);
340  }
341
342  OS << "\n# End machine code for function " << getName() << ".\n\n";
343}
344
345namespace llvm {
346  template<>
347  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
348
349  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
350
351    static std::string getGraphName(const MachineFunction *F) {
352      return "CFG for '" + F->getName().str() + "' function";
353    }
354
355    std::string getNodeLabel(const MachineBasicBlock *Node,
356                             const MachineFunction *Graph) {
357      std::string OutStr;
358      {
359        raw_string_ostream OSS(OutStr);
360
361        if (isSimple()) {
362          OSS << "BB#" << Node->getNumber();
363          if (const BasicBlock *BB = Node->getBasicBlock())
364            OSS << ": " << BB->getName();
365        } else
366          Node->print(OSS);
367      }
368
369      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
370
371      // Process string output to make it nicer...
372      for (unsigned i = 0; i != OutStr.length(); ++i)
373        if (OutStr[i] == '\n') {                            // Left justify
374          OutStr[i] = '\\';
375          OutStr.insert(OutStr.begin()+i+1, 'l');
376        }
377      return OutStr;
378    }
379  };
380}
381
382void MachineFunction::viewCFG() const
383{
384#ifndef NDEBUG
385  ViewGraph(this, "mf" + getName());
386#else
387  errs() << "MachineFunction::viewCFG is only available in debug builds on "
388         << "systems with Graphviz or gv!\n";
389#endif // NDEBUG
390}
391
392void MachineFunction::viewCFGOnly() const
393{
394#ifndef NDEBUG
395  ViewGraph(this, "mf" + getName(), true);
396#else
397  errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
398         << "systems with Graphviz or gv!\n";
399#endif // NDEBUG
400}
401
402/// addLiveIn - Add the specified physical register as a live-in value and
403/// create a corresponding virtual register for it.
404unsigned MachineFunction::addLiveIn(unsigned PReg,
405                                    const TargetRegisterClass *RC) {
406  MachineRegisterInfo &MRI = getRegInfo();
407  unsigned VReg = MRI.getLiveInVirtReg(PReg);
408  if (VReg) {
409    assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
410    return VReg;
411  }
412  VReg = MRI.createVirtualRegister(RC);
413  MRI.addLiveIn(PReg, VReg);
414  return VReg;
415}
416
417/// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
418/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
419/// normal 'L' label is returned.
420MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
421                                        bool isLinkerPrivate) const {
422  assert(JumpTableInfo && "No jump tables");
423  assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
424  const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
425
426  const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
427                                         MAI.getPrivateGlobalPrefix();
428  SmallString<60> Name;
429  raw_svector_ostream(Name)
430    << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
431  return Ctx.GetOrCreateSymbol(Name.str());
432}
433
434/// getPICBaseSymbol - Return a function-local symbol to represent the PIC
435/// base.
436MCSymbol *MachineFunction::getPICBaseSymbol() const {
437  const MCAsmInfo &MAI = *Target.getMCAsmInfo();
438  return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
439                               Twine(getFunctionNumber())+"$pb");
440}
441
442//===----------------------------------------------------------------------===//
443//  MachineFrameInfo implementation
444//===----------------------------------------------------------------------===//
445
446/// CreateFixedObject - Create a new object at a fixed location on the stack.
447/// All fixed objects should be created before other objects are created for
448/// efficiency. By default, fixed objects are immutable. This returns an
449/// index with a negative value.
450///
451int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
452                                        bool Immutable) {
453  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
454  // The alignment of the frame index can be determined from its offset from
455  // the incoming frame position.  If the frame object is at offset 32 and
456  // the stack is guaranteed to be 16-byte aligned, then we know that the
457  // object is 16-byte aligned.
458  unsigned StackAlign = TFI.getStackAlignment();
459  unsigned Align = MinAlign(SPOffset, StackAlign);
460  Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
461                                              /*isSS*/false, false));
462  return -++NumFixedObjects;
463}
464
465
466BitVector
467MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
468  assert(MBB && "MBB must be valid");
469  const MachineFunction *MF = MBB->getParent();
470  assert(MF && "MBB must be part of a MachineFunction");
471  const TargetMachine &TM = MF->getTarget();
472  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
473  BitVector BV(TRI->getNumRegs());
474
475  // Before CSI is calculated, no registers are considered pristine. They can be
476  // freely used and PEI will make sure they are saved.
477  if (!isCalleeSavedInfoValid())
478    return BV;
479
480  for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
481    BV.set(*CSR);
482
483  // The entry MBB always has all CSRs pristine.
484  if (MBB == &MF->front())
485    return BV;
486
487  // On other MBBs the saved CSRs are not pristine.
488  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
489  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
490         E = CSI.end(); I != E; ++I)
491    BV.reset(I->getReg());
492
493  return BV;
494}
495
496
497void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
498  if (Objects.empty()) return;
499
500  const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
501  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
502
503  OS << "Frame Objects:\n";
504
505  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
506    const StackObject &SO = Objects[i];
507    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
508    if (SO.Size == ~0ULL) {
509      OS << "dead\n";
510      continue;
511    }
512    if (SO.Size == 0)
513      OS << "variable sized";
514    else
515      OS << "size=" << SO.Size;
516    OS << ", align=" << SO.Alignment;
517
518    if (i < NumFixedObjects)
519      OS << ", fixed";
520    if (i < NumFixedObjects || SO.SPOffset != -1) {
521      int64_t Off = SO.SPOffset - ValOffset;
522      OS << ", at location [SP";
523      if (Off > 0)
524        OS << "+" << Off;
525      else if (Off < 0)
526        OS << Off;
527      OS << "]";
528    }
529    OS << "\n";
530  }
531}
532
533void MachineFrameInfo::dump(const MachineFunction &MF) const {
534  print(MF, dbgs());
535}
536
537//===----------------------------------------------------------------------===//
538//  MachineJumpTableInfo implementation
539//===----------------------------------------------------------------------===//
540
541/// getEntrySize - Return the size of each entry in the jump table.
542unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
543  // The size of a jump table entry is 4 bytes unless the entry is just the
544  // address of a block, in which case it is the pointer size.
545  switch (getEntryKind()) {
546  case MachineJumpTableInfo::EK_BlockAddress:
547    return TD.getPointerSize();
548  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
549    return 8;
550  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
551  case MachineJumpTableInfo::EK_LabelDifference32:
552  case MachineJumpTableInfo::EK_Custom32:
553    return 4;
554  case MachineJumpTableInfo::EK_Inline:
555    return 0;
556  }
557  llvm_unreachable("Unknown jump table encoding!");
558}
559
560/// getEntryAlignment - Return the alignment of each entry in the jump table.
561unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
562  // The alignment of a jump table entry is the alignment of int32 unless the
563  // entry is just the address of a block, in which case it is the pointer
564  // alignment.
565  switch (getEntryKind()) {
566  case MachineJumpTableInfo::EK_BlockAddress:
567    return TD.getPointerABIAlignment();
568  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
569    return TD.getABIIntegerTypeAlignment(64);
570  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
571  case MachineJumpTableInfo::EK_LabelDifference32:
572  case MachineJumpTableInfo::EK_Custom32:
573    return TD.getABIIntegerTypeAlignment(32);
574  case MachineJumpTableInfo::EK_Inline:
575    return 1;
576  }
577  llvm_unreachable("Unknown jump table encoding!");
578}
579
580/// createJumpTableIndex - Create a new jump table entry in the jump table info.
581///
582unsigned MachineJumpTableInfo::createJumpTableIndex(
583                               const std::vector<MachineBasicBlock*> &DestBBs) {
584  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
585  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
586  return JumpTables.size()-1;
587}
588
589/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
590/// the jump tables to branch to New instead.
591bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
592                                                  MachineBasicBlock *New) {
593  assert(Old != New && "Not making a change?");
594  bool MadeChange = false;
595  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
596    ReplaceMBBInJumpTable(i, Old, New);
597  return MadeChange;
598}
599
600/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
601/// the jump table to branch to New instead.
602bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
603                                                 MachineBasicBlock *Old,
604                                                 MachineBasicBlock *New) {
605  assert(Old != New && "Not making a change?");
606  bool MadeChange = false;
607  MachineJumpTableEntry &JTE = JumpTables[Idx];
608  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
609    if (JTE.MBBs[j] == Old) {
610      JTE.MBBs[j] = New;
611      MadeChange = true;
612    }
613  return MadeChange;
614}
615
616void MachineJumpTableInfo::print(raw_ostream &OS) const {
617  if (JumpTables.empty()) return;
618
619  OS << "Jump Tables:\n";
620
621  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
622    OS << "  jt#" << i << ": ";
623    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
624      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
625  }
626
627  OS << '\n';
628}
629
630void MachineJumpTableInfo::dump() const { print(dbgs()); }
631
632
633//===----------------------------------------------------------------------===//
634//  MachineConstantPool implementation
635//===----------------------------------------------------------------------===//
636
637void MachineConstantPoolValue::anchor() { }
638
639Type *MachineConstantPoolEntry::getType() const {
640  if (isMachineConstantPoolEntry())
641    return Val.MachineCPVal->getType();
642  return Val.ConstVal->getType();
643}
644
645
646unsigned MachineConstantPoolEntry::getRelocationInfo() const {
647  if (isMachineConstantPoolEntry())
648    return Val.MachineCPVal->getRelocationInfo();
649  return Val.ConstVal->getRelocationInfo();
650}
651
652MachineConstantPool::~MachineConstantPool() {
653  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
654    if (Constants[i].isMachineConstantPoolEntry())
655      delete Constants[i].Val.MachineCPVal;
656  for (DenseSet<MachineConstantPoolValue*>::iterator I =
657       MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
658       I != E; ++I)
659    delete *I;
660}
661
662/// CanShareConstantPoolEntry - Test whether the given two constants
663/// can be allocated the same constant pool entry.
664static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
665                                      const TargetData *TD) {
666  // Handle the trivial case quickly.
667  if (A == B) return true;
668
669  // If they have the same type but weren't the same constant, quickly
670  // reject them.
671  if (A->getType() == B->getType()) return false;
672
673  // We can't handle structs or arrays.
674  if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
675      isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
676    return false;
677
678  // For now, only support constants with the same size.
679  uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
680  if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
681      StoreSize > 128)
682    return false;
683
684  Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
685
686  // Try constant folding a bitcast of both instructions to an integer.  If we
687  // get two identical ConstantInt's, then we are good to share them.  We use
688  // the constant folding APIs to do this so that we get the benefit of
689  // TargetData.
690  if (isa<PointerType>(A->getType()))
691    A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
692                                 const_cast<Constant*>(A), TD);
693  else if (A->getType() != IntTy)
694    A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
695                                 const_cast<Constant*>(A), TD);
696  if (isa<PointerType>(B->getType()))
697    B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
698                                 const_cast<Constant*>(B), TD);
699  else if (B->getType() != IntTy)
700    B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
701                                 const_cast<Constant*>(B), TD);
702
703  return A == B;
704}
705
706/// getConstantPoolIndex - Create a new entry in the constant pool or return
707/// an existing one.  User must specify the log2 of the minimum required
708/// alignment for the object.
709///
710unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
711                                                   unsigned Alignment) {
712  assert(Alignment && "Alignment must be specified!");
713  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
714
715  // Check to see if we already have this constant.
716  //
717  // FIXME, this could be made much more efficient for large constant pools.
718  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
719    if (!Constants[i].isMachineConstantPoolEntry() &&
720        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
721      if ((unsigned)Constants[i].getAlignment() < Alignment)
722        Constants[i].Alignment = Alignment;
723      return i;
724    }
725
726  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
727  return Constants.size()-1;
728}
729
730unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
731                                                   unsigned Alignment) {
732  assert(Alignment && "Alignment must be specified!");
733  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
734
735  // Check to see if we already have this constant.
736  //
737  // FIXME, this could be made much more efficient for large constant pools.
738  int Idx = V->getExistingMachineCPValue(this, Alignment);
739  if (Idx != -1) {
740    MachineCPVsSharingEntries.insert(V);
741    return (unsigned)Idx;
742  }
743
744  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
745  return Constants.size()-1;
746}
747
748void MachineConstantPool::print(raw_ostream &OS) const {
749  if (Constants.empty()) return;
750
751  OS << "Constant Pool:\n";
752  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
753    OS << "  cp#" << i << ": ";
754    if (Constants[i].isMachineConstantPoolEntry())
755      Constants[i].Val.MachineCPVal->print(OS);
756    else
757      OS << *(const Value*)Constants[i].Val.ConstVal;
758    OS << ", align=" << Constants[i].getAlignment();
759    OS << "\n";
760  }
761}
762
763void MachineConstantPool::dump() const { print(dbgs()); }
764