lib/CodeGen/MachineFunction.cpp

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