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      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/ADT/STLExtras.h"
     18 #include "llvm/ADT/SmallString.h"
     19 #include "llvm/Analysis/ConstantFolding.h"
     20 #include "llvm/Assembly/Writer.h"
     21 #include "llvm/CodeGen/MachineConstantPool.h"
     22 #include "llvm/CodeGen/MachineFrameInfo.h"
     23 #include "llvm/CodeGen/MachineFunctionPass.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/DebugInfo.h"
     30 #include "llvm/IR/DataLayout.h"
     31 #include "llvm/IR/Function.h"
     32 #include "llvm/MC/MCAsmInfo.h"
     33 #include "llvm/MC/MCContext.h"
     34 #include "llvm/Support/Debug.h"
     35 #include "llvm/Support/GraphWriter.h"
     36 #include "llvm/Support/raw_ostream.h"
     37 #include "llvm/Target/TargetFrameLowering.h"
     38 #include "llvm/Target/TargetLowering.h"
     39 #include "llvm/Target/TargetMachine.h"
     40 using namespace llvm;
     41 
     42 //===----------------------------------------------------------------------===//
     43 // MachineFunction implementation
     44 //===----------------------------------------------------------------------===//
     45 
     46 // Out of line virtual method.
     47 MachineFunctionInfo::~MachineFunctionInfo() {}
     48 
     49 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
     50   MBB->getParent()->DeleteMachineBasicBlock(MBB);
     51 }
     52 
     53 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
     54                                  unsigned FunctionNum, MachineModuleInfo &mmi,
     55                                  GCModuleInfo* gmi)
     56   : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
     57   if (TM.getRegisterInfo())
     58     RegInfo = new (Allocator) MachineRegisterInfo(TM);
     59   else
     60     RegInfo = 0;
     61 
     62   MFInfo = 0;
     63   FrameInfo =
     64     new (Allocator) MachineFrameInfo(TM,!F->hasFnAttribute("no-realign-stack"));
     65 
     66   if (Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
     67                                        Attribute::StackAlignment))
     68     FrameInfo->ensureMaxAlignment(Fn->getAttributes().
     69                                 getStackAlignment(AttributeSet::FunctionIndex));
     70 
     71   ConstantPool = new (Allocator) MachineConstantPool(TM);
     72   Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
     73 
     74   // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
     75   if (!Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
     76                                         Attribute::OptimizeForSize))
     77     Alignment = std::max(Alignment,
     78                          TM.getTargetLowering()->getPrefFunctionAlignment());
     79 
     80   FunctionNumber = FunctionNum;
     81   JumpTableInfo = 0;
     82 }
     83 
     84 MachineFunction::~MachineFunction() {
     85   // Don't call destructors on MachineInstr and MachineOperand. All of their
     86   // memory comes from the BumpPtrAllocator which is about to be purged.
     87   //
     88   // Do call MachineBasicBlock destructors, it contains std::vectors.
     89   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
     90     I->Insts.clearAndLeakNodesUnsafely();
     91 
     92   InstructionRecycler.clear(Allocator);
     93   OperandRecycler.clear(Allocator);
     94   BasicBlockRecycler.clear(Allocator);
     95   if (RegInfo) {
     96     RegInfo->~MachineRegisterInfo();
     97     Allocator.Deallocate(RegInfo);
     98   }
     99   if (MFInfo) {
    100     MFInfo->~MachineFunctionInfo();
    101     Allocator.Deallocate(MFInfo);
    102   }
    103 
    104   FrameInfo->~MachineFrameInfo();
    105   Allocator.Deallocate(FrameInfo);
    106 
    107   ConstantPool->~MachineConstantPool();
    108   Allocator.Deallocate(ConstantPool);
    109 
    110   if (JumpTableInfo) {
    111     JumpTableInfo->~MachineJumpTableInfo();
    112     Allocator.Deallocate(JumpTableInfo);
    113   }
    114 }
    115 
    116 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
    117 /// does already exist, allocate one.
    118 MachineJumpTableInfo *MachineFunction::
    119 getOrCreateJumpTableInfo(unsigned EntryKind) {
    120   if (JumpTableInfo) return JumpTableInfo;
    121 
    122   JumpTableInfo = new (Allocator)
    123     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
    124   return JumpTableInfo;
    125 }
    126 
    127 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
    128 /// recomputes them.  This guarantees that the MBB numbers are sequential,
    129 /// dense, and match the ordering of the blocks within the function.  If a
    130 /// specific MachineBasicBlock is specified, only that block and those after
    131 /// it are renumbered.
    132 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
    133   if (empty()) { MBBNumbering.clear(); return; }
    134   MachineFunction::iterator MBBI, E = end();
    135   if (MBB == 0)
    136     MBBI = begin();
    137   else
    138     MBBI = MBB;
    139 
    140   // Figure out the block number this should have.
    141   unsigned BlockNo = 0;
    142   if (MBBI != begin())
    143     BlockNo = prior(MBBI)->getNumber()+1;
    144 
    145   for (; MBBI != E; ++MBBI, ++BlockNo) {
    146     if (MBBI->getNumber() != (int)BlockNo) {
    147       // Remove use of the old number.
    148       if (MBBI->getNumber() != -1) {
    149         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
    150                "MBB number mismatch!");
    151         MBBNumbering[MBBI->getNumber()] = 0;
    152       }
    153 
    154       // If BlockNo is already taken, set that block's number to -1.
    155       if (MBBNumbering[BlockNo])
    156         MBBNumbering[BlockNo]->setNumber(-1);
    157 
    158       MBBNumbering[BlockNo] = MBBI;
    159       MBBI->setNumber(BlockNo);
    160     }
    161   }
    162 
    163   // Okay, all the blocks are renumbered.  If we have compactified the block
    164   // numbering, shrink MBBNumbering now.
    165   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
    166   MBBNumbering.resize(BlockNo);
    167 }
    168 
    169 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
    170 /// of `new MachineInstr'.
    171 ///
    172 MachineInstr *
    173 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
    174                                     DebugLoc DL, bool NoImp) {
    175   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
    176     MachineInstr(*this, MCID, DL, NoImp);
    177 }
    178 
    179 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
    180 /// 'Orig' instruction, identical in all ways except the instruction
    181 /// has no parent, prev, or next.
    182 ///
    183 MachineInstr *
    184 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
    185   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
    186              MachineInstr(*this, *Orig);
    187 }
    188 
    189 /// DeleteMachineInstr - Delete the given MachineInstr.
    190 ///
    191 /// This function also serves as the MachineInstr destructor - the real
    192 /// ~MachineInstr() destructor must be empty.
    193 void
    194 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
    195   // Strip it for parts. The operand array and the MI object itself are
    196   // independently recyclable.
    197   if (MI->Operands)
    198     deallocateOperandArray(MI->CapOperands, MI->Operands);
    199   // Don't call ~MachineInstr() which must be trivial anyway because
    200   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
    201   // destructors.
    202   InstructionRecycler.Deallocate(Allocator, MI);
    203 }
    204 
    205 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
    206 /// instead of `new MachineBasicBlock'.
    207 ///
    208 MachineBasicBlock *
    209 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
    210   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
    211              MachineBasicBlock(*this, bb);
    212 }
    213 
    214 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
    215 ///
    216 void
    217 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
    218   assert(MBB->getParent() == this && "MBB parent mismatch!");
    219   MBB->~MachineBasicBlock();
    220   BasicBlockRecycler.Deallocate(Allocator, MBB);
    221 }
    222 
    223 MachineMemOperand *
    224 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
    225                                       uint64_t s, unsigned base_alignment,
    226                                       const MDNode *TBAAInfo,
    227                                       const MDNode *Ranges) {
    228   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
    229                                            TBAAInfo, Ranges);
    230 }
    231 
    232 MachineMemOperand *
    233 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
    234                                       int64_t Offset, uint64_t Size) {
    235   return new (Allocator)
    236              MachineMemOperand(MachinePointerInfo(MMO->getValue(),
    237                                                   MMO->getOffset()+Offset),
    238                                MMO->getFlags(), Size,
    239                                MMO->getBaseAlignment(), 0);
    240 }
    241 
    242 MachineInstr::mmo_iterator
    243 MachineFunction::allocateMemRefsArray(unsigned long Num) {
    244   return Allocator.Allocate<MachineMemOperand *>(Num);
    245 }
    246 
    247 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
    248 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
    249                                     MachineInstr::mmo_iterator End) {
    250   // Count the number of load mem refs.
    251   unsigned Num = 0;
    252   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
    253     if ((*I)->isLoad())
    254       ++Num;
    255 
    256   // Allocate a new array and populate it with the load information.
    257   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
    258   unsigned Index = 0;
    259   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
    260     if ((*I)->isLoad()) {
    261       if (!(*I)->isStore())
    262         // Reuse the MMO.
    263         Result[Index] = *I;
    264       else {
    265         // Clone the MMO and unset the store flag.
    266         MachineMemOperand *JustLoad =
    267           getMachineMemOperand((*I)->getPointerInfo(),
    268                                (*I)->getFlags() & ~MachineMemOperand::MOStore,
    269                                (*I)->getSize(), (*I)->getBaseAlignment(),
    270                                (*I)->getTBAAInfo());
    271         Result[Index] = JustLoad;
    272       }
    273       ++Index;
    274     }
    275   }
    276   return std::make_pair(Result, Result + Num);
    277 }
    278 
    279 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
    280 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
    281                                      MachineInstr::mmo_iterator End) {
    282   // Count the number of load mem refs.
    283   unsigned Num = 0;
    284   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
    285     if ((*I)->isStore())
    286       ++Num;
    287 
    288   // Allocate a new array and populate it with the store information.
    289   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
    290   unsigned Index = 0;
    291   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
    292     if ((*I)->isStore()) {
    293       if (!(*I)->isLoad())
    294         // Reuse the MMO.
    295         Result[Index] = *I;
    296       else {
    297         // Clone the MMO and unset the load flag.
    298         MachineMemOperand *JustStore =
    299           getMachineMemOperand((*I)->getPointerInfo(),
    300                                (*I)->getFlags() & ~MachineMemOperand::MOLoad,
    301                                (*I)->getSize(), (*I)->getBaseAlignment(),
    302                                (*I)->getTBAAInfo());
    303         Result[Index] = JustStore;
    304       }
    305       ++Index;
    306     }
    307   }
    308   return std::make_pair(Result, Result + Num);
    309 }
    310 
    311 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
    312 void MachineFunction::dump() const {
    313   print(dbgs());
    314 }
    315 #endif
    316 
    317 StringRef MachineFunction::getName() const {
    318   assert(getFunction() && "No function!");
    319   return getFunction()->getName();
    320 }
    321 
    322 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
    323   OS << "# Machine code for function " << getName() << ": ";
    324   if (RegInfo) {
    325     OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
    326     if (!RegInfo->tracksLiveness())
    327       OS << ", not tracking liveness";
    328   }
    329   OS << '\n';
    330 
    331   // Print Frame Information
    332   FrameInfo->print(*this, OS);
    333 
    334   // Print JumpTable Information
    335   if (JumpTableInfo)
    336     JumpTableInfo->print(OS);
    337 
    338   // Print Constant Pool
    339   ConstantPool->print(OS);
    340 
    341   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
    342 
    343   if (RegInfo && !RegInfo->livein_empty()) {
    344     OS << "Function Live Ins: ";
    345     for (MachineRegisterInfo::livein_iterator
    346          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
    347       OS << PrintReg(I->first, TRI);
    348       if (I->second)
    349         OS << " in " << PrintReg(I->second, TRI);
    350       if (llvm::next(I) != E)
    351         OS << ", ";
    352     }
    353     OS << '\n';
    354   }
    355 
    356   for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
    357     OS << '\n';
    358     BB->print(OS, Indexes);
    359   }
    360 
    361   OS << "\n# End machine code for function " << getName() << ".\n\n";
    362 }
    363 
    364 namespace llvm {
    365   template<>
    366   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
    367 
    368   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
    369 
    370     static std::string getGraphName(const MachineFunction *F) {
    371       return "CFG for '" + F->getName().str() + "' function";
    372     }
    373 
    374     std::string getNodeLabel(const MachineBasicBlock *Node,
    375                              const MachineFunction *Graph) {
    376       std::string OutStr;
    377       {
    378         raw_string_ostream OSS(OutStr);
    379 
    380         if (isSimple()) {
    381           OSS << "BB#" << Node->getNumber();
    382           if (const BasicBlock *BB = Node->getBasicBlock())
    383             OSS << ": " << BB->getName();
    384         } else
    385           Node->print(OSS);
    386       }
    387 
    388       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
    389 
    390       // Process string output to make it nicer...
    391       for (unsigned i = 0; i != OutStr.length(); ++i)
    392         if (OutStr[i] == '\n') {                            // Left justify
    393           OutStr[i] = '\\';
    394           OutStr.insert(OutStr.begin()+i+1, 'l');
    395         }
    396       return OutStr;
    397     }
    398   };
    399 }
    400 
    401 void MachineFunction::viewCFG() const
    402 {
    403 #ifndef NDEBUG
    404   ViewGraph(this, "mf" + getName());
    405 #else
    406   errs() << "MachineFunction::viewCFG is only available in debug builds on "
    407          << "systems with Graphviz or gv!\n";
    408 #endif // NDEBUG
    409 }
    410 
    411 void MachineFunction::viewCFGOnly() const
    412 {
    413 #ifndef NDEBUG
    414   ViewGraph(this, "mf" + getName(), true);
    415 #else
    416   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
    417          << "systems with Graphviz or gv!\n";
    418 #endif // NDEBUG
    419 }
    420 
    421 /// addLiveIn - Add the specified physical register as a live-in value and
    422 /// create a corresponding virtual register for it.
    423 unsigned MachineFunction::addLiveIn(unsigned PReg,
    424                                     const TargetRegisterClass *RC) {
    425   MachineRegisterInfo &MRI = getRegInfo();
    426   unsigned VReg = MRI.getLiveInVirtReg(PReg);
    427   if (VReg) {
    428     assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
    429     return VReg;
    430   }
    431   VReg = MRI.createVirtualRegister(RC);
    432   MRI.addLiveIn(PReg, VReg);
    433   return VReg;
    434 }
    435 
    436 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
    437 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
    438 /// normal 'L' label is returned.
    439 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
    440                                         bool isLinkerPrivate) const {
    441   assert(JumpTableInfo && "No jump tables");
    442   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
    443   const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
    444 
    445   const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
    446                                          MAI.getPrivateGlobalPrefix();
    447   SmallString<60> Name;
    448   raw_svector_ostream(Name)
    449     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
    450   return Ctx.GetOrCreateSymbol(Name.str());
    451 }
    452 
    453 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
    454 /// base.
    455 MCSymbol *MachineFunction::getPICBaseSymbol() const {
    456   const MCAsmInfo &MAI = *Target.getMCAsmInfo();
    457   return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
    458                                Twine(getFunctionNumber())+"$pb");
    459 }
    460 
    461 //===----------------------------------------------------------------------===//
    462 //  MachineFrameInfo implementation
    463 //===----------------------------------------------------------------------===//
    464 
    465 const TargetFrameLowering *MachineFrameInfo::getFrameLowering() const {
    466   return TM.getFrameLowering();
    467 }
    468 
    469 /// ensureMaxAlignment - Make sure the function is at least Align bytes
    470 /// aligned.
    471 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
    472   if (!getFrameLowering()->isStackRealignable() || !RealignOption)
    473     assert(Align <= getFrameLowering()->getStackAlignment() &&
    474            "For targets without stack realignment, Align is out of limit!");
    475   if (MaxAlignment < Align) MaxAlignment = Align;
    476 }
    477 
    478 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
    479 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
    480                                            unsigned StackAlign) {
    481   if (!ShouldClamp || Align <= StackAlign)
    482     return Align;
    483   DEBUG(dbgs() << "Warning: requested alignment " << Align
    484                << " exceeds the stack alignment " << StackAlign
    485                << " when stack realignment is off" << '\n');
    486   return StackAlign;
    487 }
    488 
    489 /// CreateStackObject - Create a new statically sized stack object, returning
    490 /// a nonnegative identifier to represent it.
    491 ///
    492 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
    493                       bool isSS, bool MayNeedSP, const AllocaInst *Alloca) {
    494   assert(Size != 0 && "Cannot allocate zero size stack objects!");
    495   Alignment =
    496     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
    497                           !RealignOption,
    498                         Alignment, getFrameLowering()->getStackAlignment());
    499   Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, MayNeedSP,
    500                                 Alloca));
    501   int Index = (int)Objects.size() - NumFixedObjects - 1;
    502   assert(Index >= 0 && "Bad frame index!");
    503   ensureMaxAlignment(Alignment);
    504   return Index;
    505 }
    506 
    507 /// CreateSpillStackObject - Create a new statically sized stack object that
    508 /// represents a spill slot, returning a nonnegative identifier to represent
    509 /// it.
    510 ///
    511 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
    512                                              unsigned Alignment) {
    513   Alignment =
    514     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
    515                           !RealignOption,
    516                         Alignment, getFrameLowering()->getStackAlignment());
    517   CreateStackObject(Size, Alignment, true, false);
    518   int Index = (int)Objects.size() - NumFixedObjects - 1;
    519   ensureMaxAlignment(Alignment);
    520   return Index;
    521 }
    522 
    523 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
    524 /// variable sized object has been created.  This must be created whenever a
    525 /// variable sized object is created, whether or not the index returned is
    526 /// actually used.
    527 ///
    528 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment) {
    529   HasVarSizedObjects = true;
    530   Alignment =
    531     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
    532                           !RealignOption,
    533                         Alignment, getFrameLowering()->getStackAlignment());
    534   Objects.push_back(StackObject(0, Alignment, 0, false, false, true, 0));
    535   ensureMaxAlignment(Alignment);
    536   return (int)Objects.size()-NumFixedObjects-1;
    537 }
    538 
    539 /// CreateFixedObject - Create a new object at a fixed location on the stack.
    540 /// All fixed objects should be created before other objects are created for
    541 /// efficiency. By default, fixed objects are immutable. This returns an
    542 /// index with a negative value.
    543 ///
    544 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
    545                                         bool Immutable) {
    546   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
    547   // The alignment of the frame index can be determined from its offset from
    548   // the incoming frame position.  If the frame object is at offset 32 and
    549   // the stack is guaranteed to be 16-byte aligned, then we know that the
    550   // object is 16-byte aligned.
    551   unsigned StackAlign = getFrameLowering()->getStackAlignment();
    552   unsigned Align = MinAlign(SPOffset, StackAlign);
    553   Align =
    554     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
    555                           !RealignOption,
    556                         Align, getFrameLowering()->getStackAlignment());
    557   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
    558                                               /*isSS*/   false,
    559                                               /*NeedSP*/ false,
    560                                               /*Alloca*/ 0));
    561   return -++NumFixedObjects;
    562 }
    563 
    564 
    565 BitVector
    566 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
    567   assert(MBB && "MBB must be valid");
    568   const MachineFunction *MF = MBB->getParent();
    569   assert(MF && "MBB must be part of a MachineFunction");
    570   const TargetMachine &TM = MF->getTarget();
    571   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
    572   BitVector BV(TRI->getNumRegs());
    573 
    574   // Before CSI is calculated, no registers are considered pristine. They can be
    575   // freely used and PEI will make sure they are saved.
    576   if (!isCalleeSavedInfoValid())
    577     return BV;
    578 
    579   for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
    580     BV.set(*CSR);
    581 
    582   // The entry MBB always has all CSRs pristine.
    583   if (MBB == &MF->front())
    584     return BV;
    585 
    586   // On other MBBs the saved CSRs are not pristine.
    587   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
    588   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
    589          E = CSI.end(); I != E; ++I)
    590     BV.reset(I->getReg());
    591 
    592   return BV;
    593 }
    594 
    595 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
    596   const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
    597   const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
    598   unsigned MaxAlign = getMaxAlignment();
    599   int Offset = 0;
    600 
    601   // This code is very, very similar to PEI::calculateFrameObjectOffsets().
    602   // It really should be refactored to share code. Until then, changes
    603   // should keep in mind that there's tight coupling between the two.
    604 
    605   for (int i = getObjectIndexBegin(); i != 0; ++i) {
    606     int FixedOff = -getObjectOffset(i);
    607     if (FixedOff > Offset) Offset = FixedOff;
    608   }
    609   for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
    610     if (isDeadObjectIndex(i))
    611       continue;
    612     Offset += getObjectSize(i);
    613     unsigned Align = getObjectAlignment(i);
    614     // Adjust to alignment boundary
    615     Offset = (Offset+Align-1)/Align*Align;
    616 
    617     MaxAlign = std::max(Align, MaxAlign);
    618   }
    619 
    620   if (adjustsStack() && TFI->hasReservedCallFrame(MF))
    621     Offset += getMaxCallFrameSize();
    622 
    623   // Round up the size to a multiple of the alignment.  If the function has
    624   // any calls or alloca's, align to the target's StackAlignment value to
    625   // ensure that the callee's frame or the alloca data is suitably aligned;
    626   // otherwise, for leaf functions, align to the TransientStackAlignment
    627   // value.
    628   unsigned StackAlign;
    629   if (adjustsStack() || hasVarSizedObjects() ||
    630       (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
    631     StackAlign = TFI->getStackAlignment();
    632   else
    633     StackAlign = TFI->getTransientStackAlignment();
    634 
    635   // If the frame pointer is eliminated, all frame offsets will be relative to
    636   // SP not FP. Align to MaxAlign so this works.
    637   StackAlign = std::max(StackAlign, MaxAlign);
    638   unsigned AlignMask = StackAlign - 1;
    639   Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
    640 
    641   return (unsigned)Offset;
    642 }
    643 
    644 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
    645   if (Objects.empty()) return;
    646 
    647   const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
    648   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
    649 
    650   OS << "Frame Objects:\n";
    651 
    652   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
    653     const StackObject &SO = Objects[i];
    654     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
    655     if (SO.Size == ~0ULL) {
    656       OS << "dead\n";
    657       continue;
    658     }
    659     if (SO.Size == 0)
    660       OS << "variable sized";
    661     else
    662       OS << "size=" << SO.Size;
    663     OS << ", align=" << SO.Alignment;
    664 
    665     if (i < NumFixedObjects)
    666       OS << ", fixed";
    667     if (i < NumFixedObjects || SO.SPOffset != -1) {
    668       int64_t Off = SO.SPOffset - ValOffset;
    669       OS << ", at location [SP";
    670       if (Off > 0)
    671         OS << "+" << Off;
    672       else if (Off < 0)
    673         OS << Off;
    674       OS << "]";
    675     }
    676     OS << "\n";
    677   }
    678 }
    679 
    680 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
    681 void MachineFrameInfo::dump(const MachineFunction &MF) const {
    682   print(MF, dbgs());
    683 }
    684 #endif
    685 
    686 //===----------------------------------------------------------------------===//
    687 //  MachineJumpTableInfo implementation
    688 //===----------------------------------------------------------------------===//
    689 
    690 /// getEntrySize - Return the size of each entry in the jump table.
    691 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
    692   // The size of a jump table entry is 4 bytes unless the entry is just the
    693   // address of a block, in which case it is the pointer size.
    694   switch (getEntryKind()) {
    695   case MachineJumpTableInfo::EK_BlockAddress:
    696     return TD.getPointerSize();
    697   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
    698     return 8;
    699   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
    700   case MachineJumpTableInfo::EK_LabelDifference32:
    701   case MachineJumpTableInfo::EK_Custom32:
    702     return 4;
    703   case MachineJumpTableInfo::EK_Inline:
    704     return 0;
    705   }
    706   llvm_unreachable("Unknown jump table encoding!");
    707 }
    708 
    709 /// getEntryAlignment - Return the alignment of each entry in the jump table.
    710 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
    711   // The alignment of a jump table entry is the alignment of int32 unless the
    712   // entry is just the address of a block, in which case it is the pointer
    713   // alignment.
    714   switch (getEntryKind()) {
    715   case MachineJumpTableInfo::EK_BlockAddress:
    716     return TD.getPointerABIAlignment();
    717   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
    718     return TD.getABIIntegerTypeAlignment(64);
    719   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
    720   case MachineJumpTableInfo::EK_LabelDifference32:
    721   case MachineJumpTableInfo::EK_Custom32:
    722     return TD.getABIIntegerTypeAlignment(32);
    723   case MachineJumpTableInfo::EK_Inline:
    724     return 1;
    725   }
    726   llvm_unreachable("Unknown jump table encoding!");
    727 }
    728 
    729 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
    730 ///
    731 unsigned MachineJumpTableInfo::createJumpTableIndex(
    732                                const std::vector<MachineBasicBlock*> &DestBBs) {
    733   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
    734   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
    735   return JumpTables.size()-1;
    736 }
    737 
    738 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
    739 /// the jump tables to branch to New instead.
    740 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
    741                                                   MachineBasicBlock *New) {
    742   assert(Old != New && "Not making a change?");
    743   bool MadeChange = false;
    744   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
    745     ReplaceMBBInJumpTable(i, Old, New);
    746   return MadeChange;
    747 }
    748 
    749 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
    750 /// the jump table to branch to New instead.
    751 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
    752                                                  MachineBasicBlock *Old,
    753                                                  MachineBasicBlock *New) {
    754   assert(Old != New && "Not making a change?");
    755   bool MadeChange = false;
    756   MachineJumpTableEntry &JTE = JumpTables[Idx];
    757   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
    758     if (JTE.MBBs[j] == Old) {
    759       JTE.MBBs[j] = New;
    760       MadeChange = true;
    761     }
    762   return MadeChange;
    763 }
    764 
    765 void MachineJumpTableInfo::print(raw_ostream &OS) const {
    766   if (JumpTables.empty()) return;
    767 
    768   OS << "Jump Tables:\n";
    769 
    770   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
    771     OS << "  jt#" << i << ": ";
    772     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
    773       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
    774   }
    775 
    776   OS << '\n';
    777 }
    778 
    779 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
    780 void MachineJumpTableInfo::dump() const { print(dbgs()); }
    781 #endif
    782 
    783 
    784 //===----------------------------------------------------------------------===//
    785 //  MachineConstantPool implementation
    786 //===----------------------------------------------------------------------===//
    787 
    788 void MachineConstantPoolValue::anchor() { }
    789 
    790 const DataLayout *MachineConstantPool::getDataLayout() const {
    791   return TM.getDataLayout();
    792 }
    793 
    794 Type *MachineConstantPoolEntry::getType() const {
    795   if (isMachineConstantPoolEntry())
    796     return Val.MachineCPVal->getType();
    797   return Val.ConstVal->getType();
    798 }
    799 
    800 
    801 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
    802   if (isMachineConstantPoolEntry())
    803     return Val.MachineCPVal->getRelocationInfo();
    804   return Val.ConstVal->getRelocationInfo();
    805 }
    806 
    807 MachineConstantPool::~MachineConstantPool() {
    808   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
    809     if (Constants[i].isMachineConstantPoolEntry())
    810       delete Constants[i].Val.MachineCPVal;
    811   for (DenseSet<MachineConstantPoolValue*>::iterator I =
    812        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
    813        I != E; ++I)
    814     delete *I;
    815 }
    816 
    817 /// CanShareConstantPoolEntry - Test whether the given two constants
    818 /// can be allocated the same constant pool entry.
    819 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
    820                                       const DataLayout *TD) {
    821   // Handle the trivial case quickly.
    822   if (A == B) return true;
    823 
    824   // If they have the same type but weren't the same constant, quickly
    825   // reject them.
    826   if (A->getType() == B->getType()) return false;
    827 
    828   // We can't handle structs or arrays.
    829   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
    830       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
    831     return false;
    832 
    833   // For now, only support constants with the same size.
    834   uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
    835   if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
    836       StoreSize > 128)
    837     return false;
    838 
    839   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
    840 
    841   // Try constant folding a bitcast of both instructions to an integer.  If we
    842   // get two identical ConstantInt's, then we are good to share them.  We use
    843   // the constant folding APIs to do this so that we get the benefit of
    844   // DataLayout.
    845   if (isa<PointerType>(A->getType()))
    846     A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
    847                                  const_cast<Constant*>(A), TD);
    848   else if (A->getType() != IntTy)
    849     A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
    850                                  const_cast<Constant*>(A), TD);
    851   if (isa<PointerType>(B->getType()))
    852     B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
    853                                  const_cast<Constant*>(B), TD);
    854   else if (B->getType() != IntTy)
    855     B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
    856                                  const_cast<Constant*>(B), TD);
    857 
    858   return A == B;
    859 }
    860 
    861 /// getConstantPoolIndex - Create a new entry in the constant pool or return
    862 /// an existing one.  User must specify the log2 of the minimum required
    863 /// alignment for the object.
    864 ///
    865 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
    866                                                    unsigned Alignment) {
    867   assert(Alignment && "Alignment must be specified!");
    868   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
    869 
    870   // Check to see if we already have this constant.
    871   //
    872   // FIXME, this could be made much more efficient for large constant pools.
    873   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
    874     if (!Constants[i].isMachineConstantPoolEntry() &&
    875         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C,
    876                                   getDataLayout())) {
    877       if ((unsigned)Constants[i].getAlignment() < Alignment)
    878         Constants[i].Alignment = Alignment;
    879       return i;
    880     }
    881 
    882   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
    883   return Constants.size()-1;
    884 }
    885 
    886 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
    887                                                    unsigned Alignment) {
    888   assert(Alignment && "Alignment must be specified!");
    889   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
    890 
    891   // Check to see if we already have this constant.
    892   //
    893   // FIXME, this could be made much more efficient for large constant pools.
    894   int Idx = V->getExistingMachineCPValue(this, Alignment);
    895   if (Idx != -1) {
    896     MachineCPVsSharingEntries.insert(V);
    897     return (unsigned)Idx;
    898   }
    899 
    900   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
    901   return Constants.size()-1;
    902 }
    903 
    904 void MachineConstantPool::print(raw_ostream &OS) const {
    905   if (Constants.empty()) return;
    906 
    907   OS << "Constant Pool:\n";
    908   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
    909     OS << "  cp#" << i << ": ";
    910     if (Constants[i].isMachineConstantPoolEntry())
    911       Constants[i].Val.MachineCPVal->print(OS);
    912     else
    913       WriteAsOperand(OS, Constants[i].Val.ConstVal, /*PrintType=*/false);
    914     OS << ", align=" << Constants[i].getAlignment();
    915     OS << "\n";
    916   }
    917 }
    918 
    919 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
    920 void MachineConstantPool::dump() const { print(dbgs()); }
    921 #endif
    922