Home | History | Annotate | Download | only in CodeGen 
      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/TargetFrameLowering.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"
     41 using namespace llvm;
     42 
     43 //===----------------------------------------------------------------------===//
     44 // MachineFunction implementation
     45 //===----------------------------------------------------------------------===//
     46 
     47 // Out of line virtual method.
     48 MachineFunctionInfo::~MachineFunctionInfo() {}
     49 
     50 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
     51   MBB->getParent()->DeleteMachineBasicBlock(MBB);
     52 }
     53 
     54 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
     55                                  unsigned FunctionNum, MachineModuleInfo &mmi,
     56                                  GCModuleInfo* gmi)
     57   : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
     58   if (TM.getRegisterInfo())
     59     RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
     60   else
     61     RegInfo = 0;
     62   MFInfo = 0;
     63   FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameLowering());
     64   if (Fn->hasFnAttr(Attribute::StackAlignment))
     65     FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
     66         Fn->getAttributes().getFnAttributes()));
     67   ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
     68   Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
     69   // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
     70   if (!Fn->hasFnAttr(Attribute::OptimizeForSize))
     71     Alignment = std::max(Alignment,
     72                          TM.getTargetLowering()->getPrefFunctionAlignment());
     73   FunctionNumber = FunctionNum;
     74   JumpTableInfo = 0;
     75 }
     76 
     77 MachineFunction::~MachineFunction() {
     78   BasicBlocks.clear();
     79   InstructionRecycler.clear(Allocator);
     80   BasicBlockRecycler.clear(Allocator);
     81   if (RegInfo) {
     82     RegInfo->~MachineRegisterInfo();
     83     Allocator.Deallocate(RegInfo);
     84   }
     85   if (MFInfo) {
     86     MFInfo->~MachineFunctionInfo();
     87     Allocator.Deallocate(MFInfo);
     88   }
     89   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
     90   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
     91 
     92   if (JumpTableInfo) {
     93     JumpTableInfo->~MachineJumpTableInfo();
     94     Allocator.Deallocate(JumpTableInfo);
     95   }
     96 }
     97 
     98 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
     99 /// does already exist, allocate one.
    100 MachineJumpTableInfo *MachineFunction::
    101 getOrCreateJumpTableInfo(unsigned EntryKind) {
    102   if (JumpTableInfo) return JumpTableInfo;
    103 
    104   JumpTableInfo = new (Allocator)
    105     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
    106   return JumpTableInfo;
    107 }
    108 
    109 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
    110 /// recomputes them.  This guarantees that the MBB numbers are sequential,
    111 /// dense, and match the ordering of the blocks within the function.  If a
    112 /// specific MachineBasicBlock is specified, only that block and those after
    113 /// it are renumbered.
    114 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
    115   if (empty()) { MBBNumbering.clear(); return; }
    116   MachineFunction::iterator MBBI, E = end();
    117   if (MBB == 0)
    118     MBBI = begin();
    119   else
    120     MBBI = MBB;
    121 
    122   // Figure out the block number this should have.
    123   unsigned BlockNo = 0;
    124   if (MBBI != begin())
    125     BlockNo = prior(MBBI)->getNumber()+1;
    126 
    127   for (; MBBI != E; ++MBBI, ++BlockNo) {
    128     if (MBBI->getNumber() != (int)BlockNo) {
    129       // Remove use of the old number.
    130       if (MBBI->getNumber() != -1) {
    131         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
    132                "MBB number mismatch!");
    133         MBBNumbering[MBBI->getNumber()] = 0;
    134       }
    135 
    136       // If BlockNo is already taken, set that block's number to -1.
    137       if (MBBNumbering[BlockNo])
    138         MBBNumbering[BlockNo]->setNumber(-1);
    139 
    140       MBBNumbering[BlockNo] = MBBI;
    141       MBBI->setNumber(BlockNo);
    142     }
    143   }
    144 
    145   // Okay, all the blocks are renumbered.  If we have compactified the block
    146   // numbering, shrink MBBNumbering now.
    147   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
    148   MBBNumbering.resize(BlockNo);
    149 }
    150 
    151 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
    152 /// of `new MachineInstr'.
    153 ///
    154 MachineInstr *
    155 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
    156                                     DebugLoc DL, bool NoImp) {
    157   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
    158     MachineInstr(MCID, DL, NoImp);
    159 }
    160 
    161 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
    162 /// 'Orig' instruction, identical in all ways except the instruction
    163 /// has no parent, prev, or next.
    164 ///
    165 MachineInstr *
    166 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
    167   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
    168              MachineInstr(*this, *Orig);
    169 }
    170 
    171 /// DeleteMachineInstr - Delete the given MachineInstr.
    172 ///
    173 void
    174 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
    175   MI->~MachineInstr();
    176   InstructionRecycler.Deallocate(Allocator, MI);
    177 }
    178 
    179 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
    180 /// instead of `new MachineBasicBlock'.
    181 ///
    182 MachineBasicBlock *
    183 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
    184   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
    185              MachineBasicBlock(*this, bb);
    186 }
    187 
    188 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
    189 ///
    190 void
    191 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
    192   assert(MBB->getParent() == this && "MBB parent mismatch!");
    193   MBB->~MachineBasicBlock();
    194   BasicBlockRecycler.Deallocate(Allocator, MBB);
    195 }
    196 
    197 MachineMemOperand *
    198 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
    199                                       uint64_t s, unsigned base_alignment,
    200                                       const MDNode *TBAAInfo) {
    201   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
    202                                            TBAAInfo);
    203 }
    204 
    205 MachineMemOperand *
    206 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
    207                                       int64_t Offset, uint64_t Size) {
    208   return new (Allocator)
    209              MachineMemOperand(MachinePointerInfo(MMO->getValue(),
    210                                                   MMO->getOffset()+Offset),
    211                                MMO->getFlags(), Size,
    212                                MMO->getBaseAlignment(), 0);
    213 }
    214 
    215 MachineInstr::mmo_iterator
    216 MachineFunction::allocateMemRefsArray(unsigned long Num) {
    217   return Allocator.Allocate<MachineMemOperand *>(Num);
    218 }
    219 
    220 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
    221 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
    222                                     MachineInstr::mmo_iterator End) {
    223   // Count the number of load mem refs.
    224   unsigned Num = 0;
    225   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
    226     if ((*I)->isLoad())
    227       ++Num;
    228 
    229   // Allocate a new array and populate it with the load information.
    230   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
    231   unsigned Index = 0;
    232   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
    233     if ((*I)->isLoad()) {
    234       if (!(*I)->isStore())
    235         // Reuse the MMO.
    236         Result[Index] = *I;
    237       else {
    238         // Clone the MMO and unset the store flag.
    239         MachineMemOperand *JustLoad =
    240           getMachineMemOperand((*I)->getPointerInfo(),
    241                                (*I)->getFlags() & ~MachineMemOperand::MOStore,
    242                                (*I)->getSize(), (*I)->getBaseAlignment(),
    243                                (*I)->getTBAAInfo());
    244         Result[Index] = JustLoad;
    245       }
    246       ++Index;
    247     }
    248   }
    249   return std::make_pair(Result, Result + Num);
    250 }
    251 
    252 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
    253 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
    254                                      MachineInstr::mmo_iterator End) {
    255   // Count the number of load mem refs.
    256   unsigned Num = 0;
    257   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
    258     if ((*I)->isStore())
    259       ++Num;
    260 
    261   // Allocate a new array and populate it with the store information.
    262   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
    263   unsigned Index = 0;
    264   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
    265     if ((*I)->isStore()) {
    266       if (!(*I)->isLoad())
    267         // Reuse the MMO.
    268         Result[Index] = *I;
    269       else {
    270         // Clone the MMO and unset the load flag.
    271         MachineMemOperand *JustStore =
    272           getMachineMemOperand((*I)->getPointerInfo(),
    273                                (*I)->getFlags() & ~MachineMemOperand::MOLoad,
    274                                (*I)->getSize(), (*I)->getBaseAlignment(),
    275                                (*I)->getTBAAInfo());
    276         Result[Index] = JustStore;
    277       }
    278       ++Index;
    279     }
    280   }
    281   return std::make_pair(Result, Result + Num);
    282 }
    283 
    284 void MachineFunction::dump() const {
    285   print(dbgs());
    286 }
    287 
    288 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
    289   OS << "# Machine code for function " << Fn->getName() << ":\n";
    290 
    291   // Print Frame Information
    292   FrameInfo->print(*this, OS);
    293 
    294   // Print JumpTable Information
    295   if (JumpTableInfo)
    296     JumpTableInfo->print(OS);
    297 
    298   // Print Constant Pool
    299   ConstantPool->print(OS);
    300 
    301   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
    302 
    303   if (RegInfo && !RegInfo->livein_empty()) {
    304     OS << "Function Live Ins: ";
    305     for (MachineRegisterInfo::livein_iterator
    306          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
    307       OS << PrintReg(I->first, TRI);
    308       if (I->second)
    309         OS << " in " << PrintReg(I->second, TRI);
    310       if (llvm::next(I) != E)
    311         OS << ", ";
    312     }
    313     OS << '\n';
    314   }
    315   if (RegInfo && !RegInfo->liveout_empty()) {
    316     OS << "Function Live Outs:";
    317     for (MachineRegisterInfo::liveout_iterator
    318          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
    319       OS << ' ' << PrintReg(*I, TRI);
    320     OS << '\n';
    321   }
    322 
    323   for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
    324     OS << '\n';
    325     BB->print(OS, Indexes);
    326   }
    327 
    328   OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
    329 }
    330 
    331 namespace llvm {
    332   template<>
    333   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
    334 
    335   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
    336 
    337     static std::string getGraphName(const MachineFunction *F) {
    338       return "CFG for '" + F->getFunction()->getNameStr() + "' function";
    339     }
    340 
    341     std::string getNodeLabel(const MachineBasicBlock *Node,
    342                              const MachineFunction *Graph) {
    343       std::string OutStr;
    344       {
    345         raw_string_ostream OSS(OutStr);
    346 
    347         if (isSimple()) {
    348           OSS << "BB#" << Node->getNumber();
    349           if (const BasicBlock *BB = Node->getBasicBlock())
    350             OSS << ": " << BB->getName();
    351         } else
    352           Node->print(OSS);
    353       }
    354 
    355       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
    356 
    357       // Process string output to make it nicer...
    358       for (unsigned i = 0; i != OutStr.length(); ++i)
    359         if (OutStr[i] == '\n') {                            // Left justify
    360           OutStr[i] = '\\';
    361           OutStr.insert(OutStr.begin()+i+1, 'l');
    362         }
    363       return OutStr;
    364     }
    365   };
    366 }
    367 
    368 void MachineFunction::viewCFG() const
    369 {
    370 #ifndef NDEBUG
    371   ViewGraph(this, "mf" + getFunction()->getNameStr());
    372 #else
    373   errs() << "MachineFunction::viewCFG is only available in debug builds on "
    374          << "systems with Graphviz or gv!\n";
    375 #endif // NDEBUG
    376 }
    377 
    378 void MachineFunction::viewCFGOnly() const
    379 {
    380 #ifndef NDEBUG
    381   ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
    382 #else
    383   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
    384          << "systems with Graphviz or gv!\n";
    385 #endif // NDEBUG
    386 }
    387 
    388 /// addLiveIn - Add the specified physical register as a live-in value and
    389 /// create a corresponding virtual register for it.
    390 unsigned MachineFunction::addLiveIn(unsigned PReg,
    391                                     const TargetRegisterClass *RC) {
    392   MachineRegisterInfo &MRI = getRegInfo();
    393   unsigned VReg = MRI.getLiveInVirtReg(PReg);
    394   if (VReg) {
    395     assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
    396     return VReg;
    397   }
    398   VReg = MRI.createVirtualRegister(RC);
    399   MRI.addLiveIn(PReg, VReg);
    400   return VReg;
    401 }
    402 
    403 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
    404 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
    405 /// normal 'L' label is returned.
    406 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
    407                                         bool isLinkerPrivate) const {
    408   assert(JumpTableInfo && "No jump tables");
    409 
    410   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
    411   const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
    412 
    413   const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
    414                                          MAI.getPrivateGlobalPrefix();
    415   SmallString<60> Name;
    416   raw_svector_ostream(Name)
    417     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
    418   return Ctx.GetOrCreateSymbol(Name.str());
    419 }
    420 
    421 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
    422 /// base.
    423 MCSymbol *MachineFunction::getPICBaseSymbol() const {
    424   const MCAsmInfo &MAI = *Target.getMCAsmInfo();
    425   return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
    426                                Twine(getFunctionNumber())+"$pb");
    427 }
    428 
    429 //===----------------------------------------------------------------------===//
    430 //  MachineFrameInfo implementation
    431 //===----------------------------------------------------------------------===//
    432 
    433 /// CreateFixedObject - Create a new object at a fixed location on the stack.
    434 /// All fixed objects should be created before other objects are created for
    435 /// efficiency. By default, fixed objects are immutable. This returns an
    436 /// index with a negative value.
    437 ///
    438 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
    439                                         bool Immutable) {
    440   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
    441   // The alignment of the frame index can be determined from its offset from
    442   // the incoming frame position.  If the frame object is at offset 32 and
    443   // the stack is guaranteed to be 16-byte aligned, then we know that the
    444   // object is 16-byte aligned.
    445   unsigned StackAlign = TFI.getStackAlignment();
    446   unsigned Align = MinAlign(SPOffset, StackAlign);
    447   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
    448                                               /*isSS*/false, false));
    449   return -++NumFixedObjects;
    450 }
    451 
    452 
    453 BitVector
    454 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
    455   assert(MBB && "MBB must be valid");
    456   const MachineFunction *MF = MBB->getParent();
    457   assert(MF && "MBB must be part of a MachineFunction");
    458   const TargetMachine &TM = MF->getTarget();
    459   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
    460   BitVector BV(TRI->getNumRegs());
    461 
    462   // Before CSI is calculated, no registers are considered pristine. They can be
    463   // freely used and PEI will make sure they are saved.
    464   if (!isCalleeSavedInfoValid())
    465     return BV;
    466 
    467   for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
    468     BV.set(*CSR);
    469 
    470   // The entry MBB always has all CSRs pristine.
    471   if (MBB == &MF->front())
    472     return BV;
    473 
    474   // On other MBBs the saved CSRs are not pristine.
    475   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
    476   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
    477          E = CSI.end(); I != E; ++I)
    478     BV.reset(I->getReg());
    479 
    480   return BV;
    481 }
    482 
    483 
    484 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
    485   if (Objects.empty()) return;
    486 
    487   const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
    488   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
    489 
    490   OS << "Frame Objects:\n";
    491 
    492   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
    493     const StackObject &SO = Objects[i];
    494     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
    495     if (SO.Size == ~0ULL) {
    496       OS << "dead\n";
    497       continue;
    498     }
    499     if (SO.Size == 0)
    500       OS << "variable sized";
    501     else
    502       OS << "size=" << SO.Size;
    503     OS << ", align=" << SO.Alignment;
    504 
    505     if (i < NumFixedObjects)
    506       OS << ", fixed";
    507     if (i < NumFixedObjects || SO.SPOffset != -1) {
    508       int64_t Off = SO.SPOffset - ValOffset;
    509       OS << ", at location [SP";
    510       if (Off > 0)
    511         OS << "+" << Off;
    512       else if (Off < 0)
    513         OS << Off;
    514       OS << "]";
    515     }
    516     OS << "\n";
    517   }
    518 }
    519 
    520 void MachineFrameInfo::dump(const MachineFunction &MF) const {
    521   print(MF, dbgs());
    522 }
    523 
    524 //===----------------------------------------------------------------------===//
    525 //  MachineJumpTableInfo implementation
    526 //===----------------------------------------------------------------------===//
    527 
    528 /// getEntrySize - Return the size of each entry in the jump table.
    529 unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
    530   // The size of a jump table entry is 4 bytes unless the entry is just the
    531   // address of a block, in which case it is the pointer size.
    532   switch (getEntryKind()) {
    533   case MachineJumpTableInfo::EK_BlockAddress:
    534     return TD.getPointerSize();
    535   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
    536   case MachineJumpTableInfo::EK_LabelDifference32:
    537   case MachineJumpTableInfo::EK_Custom32:
    538     return 4;
    539   case MachineJumpTableInfo::EK_Inline:
    540     return 0;
    541   }
    542   assert(0 && "Unknown jump table encoding!");
    543   return ~0;
    544 }
    545 
    546 /// getEntryAlignment - Return the alignment of each entry in the jump table.
    547 unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
    548   // The alignment of a jump table entry is the alignment of int32 unless the
    549   // entry is just the address of a block, in which case it is the pointer
    550   // alignment.
    551   switch (getEntryKind()) {
    552   case MachineJumpTableInfo::EK_BlockAddress:
    553     return TD.getPointerABIAlignment();
    554   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
    555   case MachineJumpTableInfo::EK_LabelDifference32:
    556   case MachineJumpTableInfo::EK_Custom32:
    557     return TD.getABIIntegerTypeAlignment(32);
    558   case MachineJumpTableInfo::EK_Inline:
    559     return 1;
    560   }
    561   assert(0 && "Unknown jump table encoding!");
    562   return ~0;
    563 }
    564 
    565 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
    566 ///
    567 unsigned MachineJumpTableInfo::createJumpTableIndex(
    568                                const std::vector<MachineBasicBlock*> &DestBBs) {
    569   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
    570   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
    571   return JumpTables.size()-1;
    572 }
    573 
    574 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
    575 /// the jump tables to branch to New instead.
    576 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
    577                                                   MachineBasicBlock *New) {
    578   assert(Old != New && "Not making a change?");
    579   bool MadeChange = false;
    580   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
    581     ReplaceMBBInJumpTable(i, Old, New);
    582   return MadeChange;
    583 }
    584 
    585 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
    586 /// the jump table to branch to New instead.
    587 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
    588                                                  MachineBasicBlock *Old,
    589                                                  MachineBasicBlock *New) {
    590   assert(Old != New && "Not making a change?");
    591   bool MadeChange = false;
    592   MachineJumpTableEntry &JTE = JumpTables[Idx];
    593   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
    594     if (JTE.MBBs[j] == Old) {
    595       JTE.MBBs[j] = New;
    596       MadeChange = true;
    597     }
    598   return MadeChange;
    599 }
    600 
    601 void MachineJumpTableInfo::print(raw_ostream &OS) const {
    602   if (JumpTables.empty()) return;
    603 
    604   OS << "Jump Tables:\n";
    605 
    606   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
    607     OS << "  jt#" << i << ": ";
    608     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
    609       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
    610   }
    611 
    612   OS << '\n';
    613 }
    614 
    615 void MachineJumpTableInfo::dump() const { print(dbgs()); }
    616 
    617 
    618 //===----------------------------------------------------------------------===//
    619 //  MachineConstantPool implementation
    620 //===----------------------------------------------------------------------===//
    621 
    622 Type *MachineConstantPoolEntry::getType() const {
    623   if (isMachineConstantPoolEntry())
    624     return Val.MachineCPVal->getType();
    625   return Val.ConstVal->getType();
    626 }
    627 
    628 
    629 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
    630   if (isMachineConstantPoolEntry())
    631     return Val.MachineCPVal->getRelocationInfo();
    632   return Val.ConstVal->getRelocationInfo();
    633 }
    634 
    635 MachineConstantPool::~MachineConstantPool() {
    636   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
    637     if (Constants[i].isMachineConstantPoolEntry())
    638       delete Constants[i].Val.MachineCPVal;
    639   for (DenseSet<MachineConstantPoolValue*>::iterator I =
    640        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
    641        I != E; ++I)
    642     delete *I;
    643 }
    644 
    645 /// CanShareConstantPoolEntry - Test whether the given two constants
    646 /// can be allocated the same constant pool entry.
    647 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
    648                                       const TargetData *TD) {
    649   // Handle the trivial case quickly.
    650   if (A == B) return true;
    651 
    652   // If they have the same type but weren't the same constant, quickly
    653   // reject them.
    654   if (A->getType() == B->getType()) return false;
    655 
    656   // For now, only support constants with the same size.
    657   if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
    658     return false;
    659 
    660   // If a floating-point value and an integer value have the same encoding,
    661   // they can share a constant-pool entry.
    662   if (const ConstantFP *AFP = dyn_cast<ConstantFP>(A))
    663     if (const ConstantInt *BI = dyn_cast<ConstantInt>(B))
    664       return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
    665   if (const ConstantFP *BFP = dyn_cast<ConstantFP>(B))
    666     if (const ConstantInt *AI = dyn_cast<ConstantInt>(A))
    667       return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
    668 
    669   // Two vectors can share an entry if each pair of corresponding
    670   // elements could.
    671   if (const ConstantVector *AV = dyn_cast<ConstantVector>(A))
    672     if (const ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
    673       if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
    674         return false;
    675       for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
    676         if (!CanShareConstantPoolEntry(AV->getOperand(i),
    677                                        BV->getOperand(i), TD))
    678           return false;
    679       return true;
    680     }
    681 
    682   // TODO: Handle other cases.
    683 
    684   return false;
    685 }
    686 
    687 /// getConstantPoolIndex - Create a new entry in the constant pool or return
    688 /// an existing one.  User must specify the log2 of the minimum required
    689 /// alignment for the object.
    690 ///
    691 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
    692                                                    unsigned Alignment) {
    693   assert(Alignment && "Alignment must be specified!");
    694   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
    695 
    696   // Check to see if we already have this constant.
    697   //
    698   // FIXME, this could be made much more efficient for large constant pools.
    699   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
    700     if (!Constants[i].isMachineConstantPoolEntry() &&
    701         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
    702       if ((unsigned)Constants[i].getAlignment() < Alignment)
    703         Constants[i].Alignment = Alignment;
    704       return i;
    705     }
    706 
    707   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
    708   return Constants.size()-1;
    709 }
    710 
    711 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
    712                                                    unsigned Alignment) {
    713   assert(Alignment && "Alignment must be specified!");
    714   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
    715 
    716   // Check to see if we already have this constant.
    717   //
    718   // FIXME, this could be made much more efficient for large constant pools.
    719   int Idx = V->getExistingMachineCPValue(this, Alignment);
    720   if (Idx != -1) {
    721     MachineCPVsSharingEntries.insert(V);
    722     return (unsigned)Idx;
    723   }
    724 
    725   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
    726   return Constants.size()-1;
    727 }
    728 
    729 void MachineConstantPool::print(raw_ostream &OS) const {
    730   if (Constants.empty()) return;
    731 
    732   OS << "Constant Pool:\n";
    733   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
    734     OS << "  cp#" << i << ": ";
    735     if (Constants[i].isMachineConstantPoolEntry())
    736       Constants[i].Val.MachineCPVal->print(OS);
    737     else
    738       OS << *(Value*)Constants[i].Val.ConstVal;
    739     OS << ", align=" << Constants[i].getAlignment();
    740     OS << "\n";
    741   }
    742 }
    743 
    744 void MachineConstantPool::dump() const { print(dbgs()); }
    745