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/ADT/STLExtras.h"
  20 #include "llvm/Config/config.h"
  21 #include "llvm/CodeGen/MachineConstantPool.h"
  22 #include "llvm/CodeGen/MachineFunction.h"
  23 #include "llvm/CodeGen/MachineFunctionPass.h"
  24 #include "llvm/CodeGen/MachineFrameInfo.h"
  25 #include "llvm/CodeGen/MachineInstr.h"
  26 #include "llvm/CodeGen/MachineJumpTableInfo.h"
  27 #include "llvm/CodeGen/MachineRegisterInfo.h"
  28 #include "llvm/CodeGen/Passes.h"
  29 #include "llvm/Target/TargetData.h"
  30 #include "llvm/Target/TargetLowering.h"
  31 #include "llvm/Target/TargetMachine.h"
  32 #include "llvm/Target/TargetFrameInfo.h"
  33 #include "llvm/Support/Compiler.h"
  34 #include "llvm/Support/GraphWriter.h"
  35 #include "llvm/Support/raw_ostream.h"
  36 using namespace llvm;
  37
  38 namespace {
  39   struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
  40     static char ID;
  41
  42     raw_ostream &OS;
  43     const std::string Banner;
  44
  45     Printer(raw_ostream &os, const std::string &banner)
  46       : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
  47
  48     const char *getPassName() const { return "MachineFunction Printer"; }
  49
  50     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  51       AU.setPreservesAll();
  52       MachineFunctionPass::getAnalysisUsage(AU);
  53     }
  54
  55     bool runOnMachineFunction(MachineFunction &MF) {
  56       OS << Banner;
  57       MF.print(OS);
  58       return false;
  59     }
  60   };
  61   char Printer::ID = 0;
  62 }
  63
  64 /// Returns a newly-created MachineFunction Printer pass. The default banner is
  65 /// empty.
  66 ///
  67 FunctionPass *llvm::createMachineFunctionPrinterPass(raw_ostream &OS,
  68                                                      const std::string &Banner){
  69   return new Printer(OS, Banner);
  70 }
  71
  72 //===---------------------------------------------------------------------===//
  73 // MachineFunction implementation
  74 //===---------------------------------------------------------------------===//
  75
  76 // Out of line virtual method.
  77 MachineFunctionInfo::~MachineFunctionInfo() {}
  78
  79 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
  80   MBB->getParent()->DeleteMachineBasicBlock(MBB);
  81 }
  82
  83 MachineFunction::MachineFunction(Function *F,
  84                                  const TargetMachine &TM)
  85   : Fn(F), Target(TM) {
  86   if (TM.getRegisterInfo())
  87     RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
  88                   MachineRegisterInfo(*TM.getRegisterInfo());
  89   else
  90     RegInfo = 0;
  91   MFInfo = 0;
  92   FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
  93                   MachineFrameInfo(*TM.getFrameInfo());
  94   ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
  95                      MachineConstantPool(TM.getTargetData());
  96   Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
  97
  98   // Set up jump table.
  99   const TargetData &TD = *TM.getTargetData();
 100   bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
 101   unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
 102   unsigned TyAlignment = IsPic ?
 103                        TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
 104                                : TD.getPointerABIAlignment();
 105   JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
 106                       MachineJumpTableInfo(EntrySize, TyAlignment);
 107 }
 108
 109 MachineFunction::~MachineFunction() {
 110   BasicBlocks.clear();
 111   InstructionRecycler.clear(Allocator);
 112   BasicBlockRecycler.clear(Allocator);
 113   if (RegInfo) {
 114     RegInfo->~MachineRegisterInfo();
 115     Allocator.Deallocate(RegInfo);
 116   }
 117   if (MFInfo) {
 118     MFInfo->~MachineFunctionInfo();
 119     Allocator.Deallocate(MFInfo);
 120   }
 121   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
 122   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
 123   JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
 124 }
 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 TargetInstrDesc &TID,
 174                                     DebugLoc DL, bool NoImp) {
 175   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 176     MachineInstr(TID, 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 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 void
 192 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 193   // Clear the instructions memoperands. This must be done manually because
 194   // the instruction's parent pointer is now null, so it can't properly
 195   // deallocate them on its own.
 196   MI->clearMemOperands(*this);
 197
 198   MI->~MachineInstr();
 199   InstructionRecycler.Deallocate(Allocator, MI);
 200 }
 201
 202 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
 203 /// instead of `new MachineBasicBlock'.
 204 ///
 205 MachineBasicBlock *
 206 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 207   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 208              MachineBasicBlock(*this, bb);
 209 }
 210
 211 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
 212 ///
 213 void
 214 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 215   assert(MBB->getParent() == this && "MBB parent mismatch!");
 216   MBB->~MachineBasicBlock();
 217   BasicBlockRecycler.Deallocate(Allocator, MBB);
 218 }
 219
 220 void MachineFunction::dump() const {
 221   print(errs());
 222 }
 223
 224 void MachineFunction::print(raw_ostream &OS) const {
 225   OS << "# Machine code for " << Fn->getName() << "():\n";
 226
 227   // Print Frame Information
 228   FrameInfo->print(*this, OS);
 229
 230   // Print JumpTable Information
 231   JumpTableInfo->print(OS);
 232
 233   // Print Constant Pool
 234   ConstantPool->print(OS);
 235
 236   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
 237
 238   if (RegInfo && !RegInfo->livein_empty()) {
 239     OS << "Live Ins:";
 240     for (MachineRegisterInfo::livein_iterator
 241          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 242       if (TRI)
 243         OS << " " << TRI->getName(I->first);
 244       else
 245         OS << " Reg #" << I->first;
 246
 247       if (I->second)
 248         OS << " in VR#" << I->second << ' ';
 249     }
 250     OS << '\n';
 251   }
 252   if (RegInfo && !RegInfo->liveout_empty()) {
 253     OS << "Live Outs:";
 254     for (MachineRegisterInfo::liveout_iterator
 255          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
 256       if (TRI)
 257         OS << ' ' << TRI->getName(*I);
 258       else
 259         OS << " Reg #" << *I;
 260     OS << '\n';
 261   }
 262
 263   for (const_iterator BB = begin(), E = end(); BB != E; ++BB)
 264     BB->print(OS);
 265
 266   OS << "\n# End machine code for " << Fn->getName() << "().\n\n";
 267 }
 268
 269 namespace llvm {
 270   template<>
 271   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 272     static std::string getGraphName(const MachineFunction *F) {
 273       return "CFG for '" + F->getFunction()->getNameStr() + "' function";
 274     }
 275
 276     static std::string getNodeLabel(const MachineBasicBlock *Node,
 277                                     const MachineFunction *Graph,
 278                                     bool ShortNames) {
 279       if (ShortNames && Node->getBasicBlock() &&
 280           !Node->getBasicBlock()->getName().empty())
 281         return Node->getBasicBlock()->getNameStr() + ":";
 282
 283       std::string OutStr;
 284       {
 285         raw_string_ostream OSS(OutStr);
 286
 287         if (ShortNames)
 288           OSS << Node->getNumber() << ':';
 289         else
 290           Node->print(OSS);
 291       }
 292
 293       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 294
 295       // Process string output to make it nicer...
 296       for (unsigned i = 0; i != OutStr.length(); ++i)
 297         if (OutStr[i] == '\n') {                            // Left justify
 298           OutStr[i] = '\\';
 299           OutStr.insert(OutStr.begin()+i+1, 'l');
 300         }
 301       return OutStr;
 302     }
 303   };
 304 }
 305
 306 void MachineFunction::viewCFG() const
 307 {
 308 #ifndef NDEBUG
 309   ViewGraph(this, "mf" + getFunction()->getNameStr());
 310 #else
 311   errs() << "SelectionDAG::viewGraph is only available in debug builds on "
 312          << "systems with Graphviz or gv!\n";
 313 #endif // NDEBUG
 314 }
 315
 316 void MachineFunction::viewCFGOnly() const
 317 {
 318 #ifndef NDEBUG
 319   ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
 320 #else
 321   errs() << "SelectionDAG::viewGraph is only available in debug builds on "
 322          << "systems with Graphviz or gv!\n";
 323 #endif // NDEBUG
 324 }
 325
 326 /// addLiveIn - Add the specified physical register as a live-in value and
 327 /// create a corresponding virtual register for it.
 328 unsigned MachineFunction::addLiveIn(unsigned PReg,
 329                                     const TargetRegisterClass *RC) {
 330   assert(RC->contains(PReg) && "Not the correct regclass!");
 331   unsigned VReg = getRegInfo().createVirtualRegister(RC);
 332   getRegInfo().addLiveIn(PReg, VReg);
 333   return VReg;
 334 }
 335
 336 /// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
 337 /// source file, line, and column. If none currently exists, create a new
 338 /// DebugLocTuple, and insert it into the DebugIdMap.
 339 unsigned MachineFunction::getOrCreateDebugLocID(MDNode *CompileUnit,
 340                                                 unsigned Line, unsigned Col) {
 341   DebugLocTuple Tuple(CompileUnit, Line, Col);
 342   DenseMap<DebugLocTuple, unsigned>::iterator II
 343     = DebugLocInfo.DebugIdMap.find(Tuple);
 344   if (II != DebugLocInfo.DebugIdMap.end())
 345     return II->second;
 346   // Add a new tuple.
 347   unsigned Id = DebugLocInfo.DebugLocations.size();
 348   DebugLocInfo.DebugLocations.push_back(Tuple);
 349   DebugLocInfo.DebugIdMap[Tuple] = Id;
 350   return Id;
 351 }
 352
 353 /// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
 354 DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
 355   unsigned Idx = DL.getIndex();
 356   assert(Idx < DebugLocInfo.DebugLocations.size() &&
 357          "Invalid index into debug locations!");
 358   return DebugLocInfo.DebugLocations[Idx];
 359 }
 360
 361 //===----------------------------------------------------------------------===//
 362 //  MachineFrameInfo implementation
 363 //===----------------------------------------------------------------------===//
 364
 365 /// CreateFixedObject - Create a new object at a fixed location on the stack.
 366 /// All fixed objects should be created before other objects are created for
 367 /// efficiency. By default, fixed objects are immutable. This returns an
 368 /// index with a negative value.
 369 ///
 370 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
 371                                         bool Immutable) {
 372   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
 373   Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
 374   return -++NumFixedObjects;
 375 }
 376
 377
 378 BitVector
 379 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
 380   assert(MBB && "MBB must be valid");
 381   const MachineFunction *MF = MBB->getParent();
 382   assert(MF && "MBB must be part of a MachineFunction");
 383   const TargetMachine &TM = MF->getTarget();
 384   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
 385   BitVector BV(TRI->getNumRegs());
 386
 387   // Before CSI is calculated, no registers are considered pristine. They can be
 388   // freely used and PEI will make sure they are saved.
 389   if (!isCalleeSavedInfoValid())
 390     return BV;
 391
 392   for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
 393     BV.set(*CSR);
 394
 395   // The entry MBB always has all CSRs pristine.
 396   if (MBB == &MF->front())
 397     return BV;
 398
 399   // On other MBBs the saved CSRs are not pristine.
 400   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
 401   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
 402          E = CSI.end(); I != E; ++I)
 403     BV.reset(I->getReg());
 404
 405   return BV;
 406 }
 407
 408
 409 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
 410   const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
 411   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
 412
 413   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
 414     const StackObject &SO = Objects[i];
 415     OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
 416     if (SO.Size == ~0ULL) {
 417       OS << "dead\n";
 418       continue;
 419     }
 420     if (SO.Size == 0)
 421       OS << "variable sized";
 422     else
 423       OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
 424     OS << " alignment is " << SO.Alignment << " byte"
 425        << (SO.Alignment != 1 ? "s," : ",");
 426
 427     if (i < NumFixedObjects)
 428       OS << " fixed";
 429     if (i < NumFixedObjects || SO.SPOffset != -1) {
 430       int64_t Off = SO.SPOffset - ValOffset;
 431       OS << " at location [SP";
 432       if (Off > 0)
 433         OS << "+" << Off;
 434       else if (Off < 0)
 435         OS << Off;
 436       OS << "]";
 437     }
 438     OS << "\n";
 439   }
 440
 441   if (HasVarSizedObjects)
 442     OS << "  Stack frame contains variable sized objects\n";
 443 }
 444
 445 void MachineFrameInfo::dump(const MachineFunction &MF) const {
 446   print(MF, errs());
 447 }
 448
 449 //===----------------------------------------------------------------------===//
 450 //  MachineJumpTableInfo implementation
 451 //===----------------------------------------------------------------------===//
 452
 453 /// getJumpTableIndex - Create a new jump table entry in the jump table info
 454 /// or return an existing one.
 455 ///
 456 unsigned MachineJumpTableInfo::getJumpTableIndex(
 457                                const std::vector<MachineBasicBlock*> &DestBBs) {
 458   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 459   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
 460     if (JumpTables[i].MBBs == DestBBs)
 461       return i;
 462
 463   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 464   return JumpTables.size()-1;
 465 }
 466
 467 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
 468 /// the jump tables to branch to New instead.
 469 bool
 470 MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 471                                              MachineBasicBlock *New) {
 472   assert(Old != New && "Not making a change?");
 473   bool MadeChange = false;
 474   for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
 475     MachineJumpTableEntry &JTE = JumpTables[i];
 476     for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 477       if (JTE.MBBs[j] == Old) {
 478         JTE.MBBs[j] = New;
 479         MadeChange = true;
 480       }
 481   }
 482   return MadeChange;
 483 }
 484
 485 void MachineJumpTableInfo::print(raw_ostream &OS) const {
 486   // FIXME: this is lame, maybe we could print out the MBB numbers or something
 487   // like {1, 2, 4, 5, 3, 0}
 488   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 489     OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
 490        << " entries\n";
 491   }
 492 }
 493
 494 void MachineJumpTableInfo::dump() const { print(errs()); }
 495
 496
 497 //===----------------------------------------------------------------------===//
 498 //  MachineConstantPool implementation
 499 //===----------------------------------------------------------------------===//
 500
 501 const Type *MachineConstantPoolEntry::getType() const {
 502   if (isMachineConstantPoolEntry())
 503     return Val.MachineCPVal->getType();
 504   return Val.ConstVal->getType();
 505 }
 506
 507
 508 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
 509   if (isMachineConstantPoolEntry())
 510     return Val.MachineCPVal->getRelocationInfo();
 511   return Val.ConstVal->getRelocationInfo();
 512 }
 513
 514 MachineConstantPool::~MachineConstantPool() {
 515   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 516     if (Constants[i].isMachineConstantPoolEntry())
 517       delete Constants[i].Val.MachineCPVal;
 518 }
 519
 520 /// getConstantPoolIndex - Create a new entry in the constant pool or return
 521 /// an existing one.  User must specify the log2 of the minimum required
 522 /// alignment for the object.
 523 ///
 524 unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
 525                                                    unsigned Alignment) {
 526   assert(Alignment && "Alignment must be specified!");
 527   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 528
 529   // Check to see if we already have this constant.
 530   //
 531   // FIXME, this could be made much more efficient for large constant pools.
 532   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 533     if (Constants[i].Val.ConstVal == C &&
 534         (Constants[i].getAlignment() & (Alignment - 1)) == 0)
 535       return i;
 536
 537   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
 538   return Constants.size()-1;
 539 }
 540
 541 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
 542                                                    unsigned Alignment) {
 543   assert(Alignment && "Alignment must be specified!");
 544   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 545
 546   // Check to see if we already have this constant.
 547   //
 548   // FIXME, this could be made much more efficient for large constant pools.
 549   int Idx = V->getExistingMachineCPValue(this, Alignment);
 550   if (Idx != -1)
 551     return (unsigned)Idx;
 552
 553   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
 554   return Constants.size()-1;
 555 }
 556
 557 void MachineConstantPool::print(raw_ostream &OS) const {
 558   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
 559     OS << "  <cp#" << i << "> is";
 560     if (Constants[i].isMachineConstantPoolEntry())
 561       Constants[i].Val.MachineCPVal->print(OS);
 562     else
 563       OS << *(Value*)Constants[i].Val.ConstVal;
 564     OS << " , alignment=" << Constants[i].getAlignment();
 565     OS << "\n";
 566   }
 567 }
 568
 569 void MachineConstantPool::dump() const { print(errs()); }