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/CodeGen/MachineConstantPool.h"
  18 #include "llvm/CodeGen/MachineFunctionPass.h"
  19 #include "llvm/CodeGen/MachineFrameInfo.h"
  20 #include "llvm/CodeGen/MachineInstr.h"
  21 #include "llvm/CodeGen/MachineJumpTableInfo.h"
  22 #include "llvm/CodeGen/MachineRegisterInfo.h"
  23 #include "llvm/CodeGen/Passes.h"
  24 #include "llvm/Target/TargetData.h"
  25 #include "llvm/Target/TargetMachine.h"
  26 #include "llvm/Target/TargetFrameInfo.h"
  27 #include "llvm/Function.h"
  28 #include "llvm/Instructions.h"
  29 #include "llvm/Support/Compiler.h"
  30 #include "llvm/Support/GraphWriter.h"
  31 #include "llvm/Support/raw_ostream.h"
  32 #include "llvm/ADT/STLExtras.h"
  33 #include "llvm/Config/config.h"
  34 #include <fstream>
  35 #include <sstream>
  36 using namespace llvm;
  37
  38 static AnnotationID MF_AID(
  39   AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
  40
  41 bool MachineFunctionPass::runOnFunction(Function &F) {
  42   // Do not codegen any 'available_externally' functions at all, they have
  43   // definitions outside the translation unit.
  44   if (F.hasAvailableExternallyLinkage())
  45     return false;
  46
  47   return runOnMachineFunction(MachineFunction::get(&F));
  48 }
  49
  50 namespace {
  51   struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
  52     static char ID;
  53
  54     std::ostream *OS;
  55     const std::string Banner;
  56
  57     Printer (std::ostream *os, const std::string &banner)
  58       : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
  59
  60     const char *getPassName() const { return "MachineFunction Printer"; }
  61
  62     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  63       AU.setPreservesAll();
  64     }
  65
  66     bool runOnMachineFunction(MachineFunction &MF) {
  67       (*OS) << Banner;
  68       MF.print (*OS);
  69       return false;
  70     }
  71   };
  72   char Printer::ID = 0;
  73 }
  74
  75 /// Returns a newly-created MachineFunction Printer pass. The default output
  76 /// stream is std::cerr; the default banner is empty.
  77 ///
  78 FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
  79                                                      const std::string &Banner){
  80   return new Printer(OS, Banner);
  81 }
  82
  83 namespace {
  84   struct VISIBILITY_HIDDEN Deleter : public MachineFunctionPass {
  85     static char ID;
  86     Deleter() : MachineFunctionPass(&ID) {}
  87
  88     const char *getPassName() const { return "Machine Code Deleter"; }
  89
  90     bool runOnMachineFunction(MachineFunction &MF) {
  91       // Delete the annotation from the function now.
  92       MachineFunction::destruct(MF.getFunction());
  93       return true;
  94     }
  95   };
  96   char Deleter::ID = 0;
  97 }
  98
  99 /// MachineCodeDeletion Pass - This pass deletes all of the machine code for
 100 /// the current function, which should happen after the function has been
 101 /// emitted to a .s file or to memory.
 102 FunctionPass *llvm::createMachineCodeDeleter() {
 103   return new Deleter();
 104 }
 105
 106
 107
 108 //===---------------------------------------------------------------------===//
 109 // MachineFunction implementation
 110 //===---------------------------------------------------------------------===//
 111
 112 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
 113   MBB->getParent()->DeleteMachineBasicBlock(MBB);
 114 }
 115
 116 MachineFunction::MachineFunction(const Function *F,
 117                                  const TargetMachine &TM)
 118   : Annotation(MF_AID), Fn(F), Target(TM) {
 119   if (TM.getRegisterInfo())
 120     RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
 121                   MachineRegisterInfo(*TM.getRegisterInfo());
 122   else
 123     RegInfo = 0;
 124   MFInfo = 0;
 125   FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
 126                   MachineFrameInfo(*TM.getFrameInfo());
 127   ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
 128                      MachineConstantPool(TM.getTargetData());
 129
 130   // Set up jump table.
 131   const TargetData &TD = *TM.getTargetData();
 132   bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
 133   unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
 134   unsigned Alignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
 135                              : TD.getPointerABIAlignment();
 136   JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
 137                       MachineJumpTableInfo(EntrySize, Alignment);
 138 }
 139
 140 MachineFunction::~MachineFunction() {
 141   BasicBlocks.clear();
 142   InstructionRecycler.clear(Allocator);
 143   BasicBlockRecycler.clear(Allocator);
 144   if (RegInfo)
 145     RegInfo->~MachineRegisterInfo();        Allocator.Deallocate(RegInfo);
 146   if (MFInfo) {
 147     MFInfo->~MachineFunctionInfo();       Allocator.Deallocate(MFInfo);
 148   }
 149   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
 150   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
 151   JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
 152 }
 153
 154
 155 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
 156 /// recomputes them.  This guarantees that the MBB numbers are sequential,
 157 /// dense, and match the ordering of the blocks within the function.  If a
 158 /// specific MachineBasicBlock is specified, only that block and those after
 159 /// it are renumbered.
 160 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 161   if (empty()) { MBBNumbering.clear(); return; }
 162   MachineFunction::iterator MBBI, E = end();
 163   if (MBB == 0)
 164     MBBI = begin();
 165   else
 166     MBBI = MBB;
 167
 168   // Figure out the block number this should have.
 169   unsigned BlockNo = 0;
 170   if (MBBI != begin())
 171     BlockNo = prior(MBBI)->getNumber()+1;
 172
 173   for (; MBBI != E; ++MBBI, ++BlockNo) {
 174     if (MBBI->getNumber() != (int)BlockNo) {
 175       // Remove use of the old number.
 176       if (MBBI->getNumber() != -1) {
 177         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 178                "MBB number mismatch!");
 179         MBBNumbering[MBBI->getNumber()] = 0;
 180       }
 181
 182       // If BlockNo is already taken, set that block's number to -1.
 183       if (MBBNumbering[BlockNo])
 184         MBBNumbering[BlockNo]->setNumber(-1);
 185
 186       MBBNumbering[BlockNo] = MBBI;
 187       MBBI->setNumber(BlockNo);
 188     }
 189   }
 190
 191   // Okay, all the blocks are renumbered.  If we have compactified the block
 192   // numbering, shrink MBBNumbering now.
 193   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 194   MBBNumbering.resize(BlockNo);
 195 }
 196
 197 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
 198 /// of `new MachineInstr'.
 199 ///
 200 MachineInstr *
 201 MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
 202                                     DebugLoc DL, bool NoImp) {
 203   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 204     MachineInstr(TID, DL, NoImp);
 205 }
 206
 207 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
 208 /// 'Orig' instruction, identical in all ways except the the instruction
 209 /// has no parent, prev, or next.
 210 ///
 211 MachineInstr *
 212 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 213   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 214              MachineInstr(*this, *Orig);
 215 }
 216
 217 /// DeleteMachineInstr - Delete the given MachineInstr.
 218 ///
 219 void
 220 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 221   // Clear the instructions memoperands. This must be done manually because
 222   // the instruction's parent pointer is now null, so it can't properly
 223   // deallocate them on its own.
 224   MI->clearMemOperands(*this);
 225
 226   MI->~MachineInstr();
 227   InstructionRecycler.Deallocate(Allocator, MI);
 228 }
 229
 230 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
 231 /// instead of `new MachineBasicBlock'.
 232 ///
 233 MachineBasicBlock *
 234 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 235   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 236              MachineBasicBlock(*this, bb);
 237 }
 238
 239 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
 240 ///
 241 void
 242 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 243   assert(MBB->getParent() == this && "MBB parent mismatch!");
 244   MBB->~MachineBasicBlock();
 245   BasicBlockRecycler.Deallocate(Allocator, MBB);
 246 }
 247
 248 void MachineFunction::dump() const {
 249   print(*cerr.stream());
 250 }
 251
 252 void MachineFunction::print(std::ostream &OS) const {
 253   OS << "# Machine code for " << Fn->getName () << "():\n";
 254
 255   // Print Frame Information
 256   FrameInfo->print(*this, OS);
 257
 258   // Print JumpTable Information
 259   JumpTableInfo->print(OS);
 260
 261   // Print Constant Pool
 262   {
 263     raw_os_ostream OSS(OS);
 264     ConstantPool->print(OSS);
 265   }
 266
 267   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
 268
 269   if (RegInfo && !RegInfo->livein_empty()) {
 270     OS << "Live Ins:";
 271     for (MachineRegisterInfo::livein_iterator
 272          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 273       if (TRI)
 274         OS << " " << TRI->getName(I->first);
 275       else
 276         OS << " Reg #" << I->first;
 277
 278       if (I->second)
 279         OS << " in VR#" << I->second << " ";
 280     }
 281     OS << "\n";
 282   }
 283   if (RegInfo && !RegInfo->liveout_empty()) {
 284     OS << "Live Outs:";
 285     for (MachineRegisterInfo::liveout_iterator
 286          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
 287       if (TRI)
 288         OS << " " << TRI->getName(*I);
 289       else
 290         OS << " Reg #" << *I;
 291     OS << "\n";
 292   }
 293
 294   for (const_iterator BB = begin(); BB != end(); ++BB)
 295     BB->print(OS);
 296
 297   OS << "\n# End machine code for " << Fn->getName () << "().\n\n";
 298 }
 299
 300 /// CFGOnly flag - This is used to control whether or not the CFG graph printer
 301 /// prints out the contents of basic blocks or not.  This is acceptable because
 302 /// this code is only really used for debugging purposes.
 303 ///
 304 static bool CFGOnly = false;
 305
 306 namespace llvm {
 307   template<>
 308   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 309     static std::string getGraphName(const MachineFunction *F) {
 310       return "CFG for '" + F->getFunction()->getName() + "' function";
 311     }
 312
 313     static std::string getNodeLabel(const MachineBasicBlock *Node,
 314                                     const MachineFunction *Graph) {
 315       if (CFGOnly && Node->getBasicBlock() &&
 316           !Node->getBasicBlock()->getName().empty())
 317         return Node->getBasicBlock()->getName() + ":";
 318
 319       std::ostringstream Out;
 320       if (CFGOnly) {
 321         Out << Node->getNumber() << ':';
 322         return Out.str();
 323       }
 324
 325       Node->print(Out);
 326
 327       std::string OutStr = Out.str();
 328       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 329
 330       // Process string output to make it nicer...
 331       for (unsigned i = 0; i != OutStr.length(); ++i)
 332         if (OutStr[i] == '\n') {                            // Left justify
 333           OutStr[i] = '\\';
 334           OutStr.insert(OutStr.begin()+i+1, 'l');
 335         }
 336       return OutStr;
 337     }
 338   };
 339 }
 340
 341 void MachineFunction::viewCFG() const
 342 {
 343 #ifndef NDEBUG
 344   ViewGraph(this, "mf" + getFunction()->getName());
 345 #else
 346   cerr << "SelectionDAG::viewGraph is only available in debug builds on "
 347        << "systems with Graphviz or gv!\n";
 348 #endif // NDEBUG
 349 }
 350
 351 void MachineFunction::viewCFGOnly() const
 352 {
 353   CFGOnly = true;
 354   viewCFG();
 355   CFGOnly = false;
 356 }
 357
 358 // The next two methods are used to construct and to retrieve
 359 // the MachineCodeForFunction object for the given function.
 360 // construct() -- Allocates and initializes for a given function and target
 361 // get()       -- Returns a handle to the object.
 362 //                This should not be called before "construct()"
 363 //                for a given Function.
 364 //
 365 MachineFunction&
 366 MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
 367 {
 368   assert(Fn->getAnnotation(MF_AID) == 0 &&
 369          "Object already exists for this function!");
 370   MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
 371   Fn->addAnnotation(mcInfo);
 372   return *mcInfo;
 373 }
 374
 375 void MachineFunction::destruct(const Function *Fn) {
 376   bool Deleted = Fn->deleteAnnotation(MF_AID);
 377   assert(Deleted && "Machine code did not exist for function!");
 378   Deleted = Deleted; // silence warning when no assertions.
 379 }
 380
 381 MachineFunction& MachineFunction::get(const Function *F)
 382 {
 383   MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
 384   assert(mc && "Call construct() method first to allocate the object");
 385   return *mc;
 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   assert(RC->contains(PReg) && "Not the correct regclass!");
 393   unsigned VReg = getRegInfo().createVirtualRegister(RC);
 394   getRegInfo().addLiveIn(PReg, VReg);
 395   return VReg;
 396 }
 397
 398 /// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
 399 /// source file, line, and column. If none currently exists, create a new
 400 /// DebugLocTuple, and insert it into the DebugIdMap.
 401 unsigned MachineFunction::getOrCreateDebugLocID(unsigned Src, unsigned Line,
 402                                                 unsigned Col) {
 403   DebugLocTuple Tuple(Src, Line, Col);
 404   DenseMap<DebugLocTuple, unsigned>::iterator II
 405     = DebugLocInfo.DebugIdMap.find(Tuple);
 406   if (II != DebugLocInfo.DebugIdMap.end())
 407     return II->second;
 408   // Add a new tuple.
 409   unsigned Id = DebugLocInfo.DebugLocations.size();
 410   DebugLocInfo.DebugLocations.push_back(Tuple);
 411   DebugLocInfo.DebugIdMap[Tuple] = Id;
 412   return Id;
 413 }
 414
 415 /// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
 416 DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
 417   unsigned Idx = DL.getIndex();
 418   assert(Idx < DebugLocInfo.DebugLocations.size() &&
 419          "Invalid index into debug locations!");
 420   return DebugLocInfo.DebugLocations[Idx];
 421 }
 422
 423 //===----------------------------------------------------------------------===//
 424 //  MachineFrameInfo implementation
 425 //===----------------------------------------------------------------------===//
 426
 427 /// CreateFixedObject - Create a new object at a fixed location on the stack.
 428 /// All fixed objects should be created before other objects are created for
 429 /// efficiency. By default, fixed objects are immutable. This returns an
 430 /// index with a negative value.
 431 ///
 432 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
 433                                         bool Immutable) {
 434   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
 435   Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
 436   return -++NumFixedObjects;
 437 }
 438
 439
 440 void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
 441   const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
 442   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
 443
 444   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
 445     const StackObject &SO = Objects[i];
 446     OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
 447     if (SO.Size == ~0ULL) {
 448       OS << "dead\n";
 449       continue;
 450     }
 451     if (SO.Size == 0)
 452       OS << "variable sized";
 453     else
 454       OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
 455     OS << " alignment is " << SO.Alignment << " byte"
 456        << (SO.Alignment != 1 ? "s," : ",");
 457
 458     if (i < NumFixedObjects)
 459       OS << " fixed";
 460     if (i < NumFixedObjects || SO.SPOffset != -1) {
 461       int64_t Off = SO.SPOffset - ValOffset;
 462       OS << " at location [SP";
 463       if (Off > 0)
 464         OS << "+" << Off;
 465       else if (Off < 0)
 466         OS << Off;
 467       OS << "]";
 468     }
 469     OS << "\n";
 470   }
 471
 472   if (HasVarSizedObjects)
 473     OS << "  Stack frame contains variable sized objects\n";
 474 }
 475
 476 void MachineFrameInfo::dump(const MachineFunction &MF) const {
 477   print(MF, *cerr.stream());
 478 }
 479
 480
 481 //===----------------------------------------------------------------------===//
 482 //  MachineJumpTableInfo implementation
 483 //===----------------------------------------------------------------------===//
 484
 485 /// getJumpTableIndex - Create a new jump table entry in the jump table info
 486 /// or return an existing one.
 487 ///
 488 unsigned MachineJumpTableInfo::getJumpTableIndex(
 489                                const std::vector<MachineBasicBlock*> &DestBBs) {
 490   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 491   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
 492     if (JumpTables[i].MBBs == DestBBs)
 493       return i;
 494
 495   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 496   return JumpTables.size()-1;
 497 }
 498
 499 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
 500 /// the jump tables to branch to New instead.
 501 bool
 502 MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 503                                              MachineBasicBlock *New) {
 504   assert(Old != New && "Not making a change?");
 505   bool MadeChange = false;
 506   for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
 507     MachineJumpTableEntry &JTE = JumpTables[i];
 508     for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 509       if (JTE.MBBs[j] == Old) {
 510         JTE.MBBs[j] = New;
 511         MadeChange = true;
 512       }
 513   }
 514   return MadeChange;
 515 }
 516
 517 void MachineJumpTableInfo::print(std::ostream &OS) const {
 518   // FIXME: this is lame, maybe we could print out the MBB numbers or something
 519   // like {1, 2, 4, 5, 3, 0}
 520   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 521     OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
 522        << " entries\n";
 523   }
 524 }
 525
 526 void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
 527
 528
 529 //===----------------------------------------------------------------------===//
 530 //  MachineConstantPool implementation
 531 //===----------------------------------------------------------------------===//
 532
 533 const Type *MachineConstantPoolEntry::getType() const {
 534   if (isMachineConstantPoolEntry())
 535       return Val.MachineCPVal->getType();
 536   return Val.ConstVal->getType();
 537 }
 538
 539 MachineConstantPool::~MachineConstantPool() {
 540   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 541     if (Constants[i].isMachineConstantPoolEntry())
 542       delete Constants[i].Val.MachineCPVal;
 543 }
 544
 545 /// getConstantPoolIndex - Create a new entry in the constant pool or return
 546 /// an existing one.  User must specify the log2 of the minimum required
 547 /// alignment for the object.
 548 ///
 549 unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
 550                                                    unsigned Alignment) {
 551   assert(Alignment && "Alignment must be specified!");
 552   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 553
 554   // Check to see if we already have this constant.
 555   //
 556   // FIXME, this could be made much more efficient for large constant pools.
 557   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 558     if (Constants[i].Val.ConstVal == C &&
 559         (Constants[i].getAlignment() & (Alignment - 1)) == 0)
 560       return i;
 561
 562   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
 563   return Constants.size()-1;
 564 }
 565
 566 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
 567                                                    unsigned Alignment) {
 568   assert(Alignment && "Alignment must be specified!");
 569   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 570
 571   // Check to see if we already have this constant.
 572   //
 573   // FIXME, this could be made much more efficient for large constant pools.
 574   int Idx = V->getExistingMachineCPValue(this, Alignment);
 575   if (Idx != -1)
 576     return (unsigned)Idx;
 577
 578   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
 579   return Constants.size()-1;
 580 }
 581
 582 void MachineConstantPool::print(raw_ostream &OS) const {
 583   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
 584     OS << "  <cp#" << i << "> is";
 585     if (Constants[i].isMachineConstantPoolEntry())
 586       Constants[i].Val.MachineCPVal->print(OS);
 587     else
 588       OS << *(Value*)Constants[i].Val.ConstVal;
 589     OS << " , alignment=" << Constants[i].getAlignment();
 590     OS << "\n";
 591   }
 592 }
 593
 594 void MachineConstantPool::dump() const { print(errs()); }