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 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
  77   MBB->getParent()->DeleteMachineBasicBlock(MBB);
  78 }
  79
  80 MachineFunction::MachineFunction(Function *F,
  81                                  const TargetMachine &TM)
  82   : Fn(F), Target(TM) {
  83   if (TM.getRegisterInfo())
  84     RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
  85                   MachineRegisterInfo(*TM.getRegisterInfo());
  86   else
  87     RegInfo = 0;
  88   MFInfo = 0;
  89   FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
  90                   MachineFrameInfo(*TM.getFrameInfo());
  91   ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
  92                      MachineConstantPool(TM.getTargetData());
  93   Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
  94
  95   // Set up jump table.
  96   const TargetData &TD = *TM.getTargetData();
  97   bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
  98   unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
  99   unsigned TyAlignment = IsPic ?
 100                        TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
 101                                : TD.getPointerABIAlignment();
 102   JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
 103                       MachineJumpTableInfo(EntrySize, TyAlignment);
 104 }
 105
 106 MachineFunction::~MachineFunction() {
 107   BasicBlocks.clear();
 108   InstructionRecycler.clear(Allocator);
 109   BasicBlockRecycler.clear(Allocator);
 110   if (RegInfo) {
 111     RegInfo->~MachineRegisterInfo();
 112     Allocator.Deallocate(RegInfo);
 113   }
 114   if (MFInfo) {
 115     MFInfo->~MachineFunctionInfo();
 116     Allocator.Deallocate(MFInfo);
 117   }
 118   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
 119   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
 120   JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
 121 }
 122
 123
 124 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
 125 /// recomputes them.  This guarantees that the MBB numbers are sequential,
 126 /// dense, and match the ordering of the blocks within the function.  If a
 127 /// specific MachineBasicBlock is specified, only that block and those after
 128 /// it are renumbered.
 129 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 130   if (empty()) { MBBNumbering.clear(); return; }
 131   MachineFunction::iterator MBBI, E = end();
 132   if (MBB == 0)
 133     MBBI = begin();
 134   else
 135     MBBI = MBB;
 136
 137   // Figure out the block number this should have.
 138   unsigned BlockNo = 0;
 139   if (MBBI != begin())
 140     BlockNo = prior(MBBI)->getNumber()+1;
 141
 142   for (; MBBI != E; ++MBBI, ++BlockNo) {
 143     if (MBBI->getNumber() != (int)BlockNo) {
 144       // Remove use of the old number.
 145       if (MBBI->getNumber() != -1) {
 146         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 147                "MBB number mismatch!");
 148         MBBNumbering[MBBI->getNumber()] = 0;
 149       }
 150
 151       // If BlockNo is already taken, set that block's number to -1.
 152       if (MBBNumbering[BlockNo])
 153         MBBNumbering[BlockNo]->setNumber(-1);
 154
 155       MBBNumbering[BlockNo] = MBBI;
 156       MBBI->setNumber(BlockNo);
 157     }
 158   }
 159
 160   // Okay, all the blocks are renumbered.  If we have compactified the block
 161   // numbering, shrink MBBNumbering now.
 162   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 163   MBBNumbering.resize(BlockNo);
 164 }
 165
 166 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
 167 /// of `new MachineInstr'.
 168 ///
 169 MachineInstr *
 170 MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
 171                                     DebugLoc DL, bool NoImp) {
 172   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 173     MachineInstr(TID, DL, NoImp);
 174 }
 175
 176 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
 177 /// 'Orig' instruction, identical in all ways except the the instruction
 178 /// has no parent, prev, or next.
 179 ///
 180 MachineInstr *
 181 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 182   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 183              MachineInstr(*this, *Orig);
 184 }
 185
 186 /// DeleteMachineInstr - Delete the given MachineInstr.
 187 ///
 188 void
 189 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 190   // Clear the instructions memoperands. This must be done manually because
 191   // the instruction's parent pointer is now null, so it can't properly
 192   // deallocate them on its own.
 193   MI->clearMemOperands(*this);
 194
 195   MI->~MachineInstr();
 196   InstructionRecycler.Deallocate(Allocator, MI);
 197 }
 198
 199 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
 200 /// instead of `new MachineBasicBlock'.
 201 ///
 202 MachineBasicBlock *
 203 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 204   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 205              MachineBasicBlock(*this, bb);
 206 }
 207
 208 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
 209 ///
 210 void
 211 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 212   assert(MBB->getParent() == this && "MBB parent mismatch!");
 213   MBB->~MachineBasicBlock();
 214   BasicBlockRecycler.Deallocate(Allocator, MBB);
 215 }
 216
 217 void MachineFunction::dump() const {
 218   print(errs());
 219 }
 220
 221 void MachineFunction::print(raw_ostream &OS) const {
 222   OS << "# Machine code for " << Fn->getName() << "():\n";
 223
 224   // Print Frame Information
 225   FrameInfo->print(*this, OS);
 226
 227   // Print JumpTable Information
 228   JumpTableInfo->print(OS);
 229
 230   // Print Constant Pool
 231   ConstantPool->print(OS);
 232
 233   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
 234
 235   if (RegInfo && !RegInfo->livein_empty()) {
 236     OS << "Live Ins:";
 237     for (MachineRegisterInfo::livein_iterator
 238          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 239       if (TRI)
 240         OS << " " << TRI->getName(I->first);
 241       else
 242         OS << " Reg #" << I->first;
 243
 244       if (I->second)
 245         OS << " in VR#" << I->second << ' ';
 246     }
 247     OS << '\n';
 248   }
 249   if (RegInfo && !RegInfo->liveout_empty()) {
 250     OS << "Live Outs:";
 251     for (MachineRegisterInfo::liveout_iterator
 252          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
 253       if (TRI)
 254         OS << ' ' << TRI->getName(*I);
 255       else
 256         OS << " Reg #" << *I;
 257     OS << '\n';
 258   }
 259
 260   for (const_iterator BB = begin(), E = end(); BB != E; ++BB)
 261     BB->print(OS);
 262
 263   OS << "\n# End machine code for " << Fn->getName() << "().\n\n";
 264 }
 265
 266 namespace llvm {
 267   template<>
 268   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 269     static std::string getGraphName(const MachineFunction *F) {
 270       return "CFG for '" + F->getFunction()->getNameStr() + "' function";
 271     }
 272
 273     static std::string getNodeLabel(const MachineBasicBlock *Node,
 274                                     const MachineFunction *Graph,
 275                                     bool ShortNames) {
 276       if (ShortNames && Node->getBasicBlock() &&
 277           !Node->getBasicBlock()->getName().empty())
 278         return Node->getBasicBlock()->getNameStr() + ":";
 279
 280       std::string OutStr;
 281       {
 282         raw_string_ostream OSS(OutStr);
 283
 284         if (ShortNames)
 285           OSS << Node->getNumber() << ':';
 286         else
 287           Node->print(OSS);
 288       }
 289
 290       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 291
 292       // Process string output to make it nicer...
 293       for (unsigned i = 0; i != OutStr.length(); ++i)
 294         if (OutStr[i] == '\n') {                            // Left justify
 295           OutStr[i] = '\\';
 296           OutStr.insert(OutStr.begin()+i+1, 'l');
 297         }
 298       return OutStr;
 299     }
 300   };
 301 }
 302
 303 void MachineFunction::viewCFG() const
 304 {
 305 #ifndef NDEBUG
 306   ViewGraph(this, "mf" + getFunction()->getNameStr());
 307 #else
 308   errs() << "SelectionDAG::viewGraph is only available in debug builds on "
 309          << "systems with Graphviz or gv!\n";
 310 #endif // NDEBUG
 311 }
 312
 313 void MachineFunction::viewCFGOnly() const
 314 {
 315 #ifndef NDEBUG
 316   ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
 317 #else
 318   errs() << "SelectionDAG::viewGraph is only available in debug builds on "
 319          << "systems with Graphviz or gv!\n";
 320 #endif // NDEBUG
 321 }
 322
 323 /// addLiveIn - Add the specified physical register as a live-in value and
 324 /// create a corresponding virtual register for it.
 325 unsigned MachineFunction::addLiveIn(unsigned PReg,
 326                                     const TargetRegisterClass *RC) {
 327   assert(RC->contains(PReg) && "Not the correct regclass!");
 328   unsigned VReg = getRegInfo().createVirtualRegister(RC);
 329   getRegInfo().addLiveIn(PReg, VReg);
 330   return VReg;
 331 }
 332
 333 /// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
 334 /// source file, line, and column. If none currently exists, create a new
 335 /// DebugLocTuple, and insert it into the DebugIdMap.
 336 unsigned MachineFunction::getOrCreateDebugLocID(MDNode *CompileUnit,
 337                                                 unsigned Line, unsigned Col) {
 338   DebugLocTuple Tuple(CompileUnit, Line, Col);
 339   DenseMap<DebugLocTuple, unsigned>::iterator II
 340     = DebugLocInfo.DebugIdMap.find(Tuple);
 341   if (II != DebugLocInfo.DebugIdMap.end())
 342     return II->second;
 343   // Add a new tuple.
 344   unsigned Id = DebugLocInfo.DebugLocations.size();
 345   DebugLocInfo.DebugLocations.push_back(Tuple);
 346   DebugLocInfo.DebugIdMap[Tuple] = Id;
 347   return Id;
 348 }
 349
 350 /// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
 351 DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
 352   unsigned Idx = DL.getIndex();
 353   assert(Idx < DebugLocInfo.DebugLocations.size() &&
 354          "Invalid index into debug locations!");
 355   return DebugLocInfo.DebugLocations[Idx];
 356 }
 357
 358 //===----------------------------------------------------------------------===//
 359 //  MachineFrameInfo implementation
 360 //===----------------------------------------------------------------------===//
 361
 362 /// CreateFixedObject - Create a new object at a fixed location on the stack.
 363 /// All fixed objects should be created before other objects are created for
 364 /// efficiency. By default, fixed objects are immutable. This returns an
 365 /// index with a negative value.
 366 ///
 367 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
 368                                         bool Immutable) {
 369   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
 370   Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
 371   return -++NumFixedObjects;
 372 }
 373
 374
 375 BitVector
 376 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
 377   assert(MBB && "MBB must be valid");
 378   const MachineFunction *MF = MBB->getParent();
 379   assert(MF && "MBB must be part of a MachineFunction");
 380   const TargetMachine &TM = MF->getTarget();
 381   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
 382   BitVector BV(TRI->getNumRegs());
 383
 384   // Before CSI is calculated, no registers are considered pristine. They can be
 385   // freely used and PEI will make sure they are saved.
 386   if (!isCalleeSavedInfoValid())
 387     return BV;
 388
 389   for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
 390     BV.set(*CSR);
 391
 392   // The entry MBB always has all CSRs pristine.
 393   if (MBB == &MF->front())
 394     return BV;
 395
 396   // On other MBBs the saved CSRs are not pristine.
 397   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
 398   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
 399          E = CSI.end(); I != E; ++I)
 400     BV.reset(I->getReg());
 401
 402   return BV;
 403 }
 404
 405
 406 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
 407   const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
 408   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
 409
 410   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
 411     const StackObject &SO = Objects[i];
 412     OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
 413     if (SO.Size == ~0ULL) {
 414       OS << "dead\n";
 415       continue;
 416     }
 417     if (SO.Size == 0)
 418       OS << "variable sized";
 419     else
 420       OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
 421     OS << " alignment is " << SO.Alignment << " byte"
 422        << (SO.Alignment != 1 ? "s," : ",");
 423
 424     if (i < NumFixedObjects)
 425       OS << " fixed";
 426     if (i < NumFixedObjects || SO.SPOffset != -1) {
 427       int64_t Off = SO.SPOffset - ValOffset;
 428       OS << " at location [SP";
 429       if (Off > 0)
 430         OS << "+" << Off;
 431       else if (Off < 0)
 432         OS << Off;
 433       OS << "]";
 434     }
 435     OS << "\n";
 436   }
 437
 438   if (HasVarSizedObjects)
 439     OS << "  Stack frame contains variable sized objects\n";
 440 }
 441
 442 void MachineFrameInfo::dump(const MachineFunction &MF) const {
 443   print(MF, errs());
 444 }
 445
 446 //===----------------------------------------------------------------------===//
 447 //  MachineJumpTableInfo implementation
 448 //===----------------------------------------------------------------------===//
 449
 450 /// getJumpTableIndex - Create a new jump table entry in the jump table info
 451 /// or return an existing one.
 452 ///
 453 unsigned MachineJumpTableInfo::getJumpTableIndex(
 454                                const std::vector<MachineBasicBlock*> &DestBBs) {
 455   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 456   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
 457     if (JumpTables[i].MBBs == DestBBs)
 458       return i;
 459
 460   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 461   return JumpTables.size()-1;
 462 }
 463
 464 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
 465 /// the jump tables to branch to New instead.
 466 bool
 467 MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 468                                              MachineBasicBlock *New) {
 469   assert(Old != New && "Not making a change?");
 470   bool MadeChange = false;
 471   for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
 472     MachineJumpTableEntry &JTE = JumpTables[i];
 473     for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 474       if (JTE.MBBs[j] == Old) {
 475         JTE.MBBs[j] = New;
 476         MadeChange = true;
 477       }
 478   }
 479   return MadeChange;
 480 }
 481
 482 void MachineJumpTableInfo::print(raw_ostream &OS) const {
 483   // FIXME: this is lame, maybe we could print out the MBB numbers or something
 484   // like {1, 2, 4, 5, 3, 0}
 485   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 486     OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
 487        << " entries\n";
 488   }
 489 }
 490
 491 void MachineJumpTableInfo::dump() const { print(errs()); }
 492
 493
 494 //===----------------------------------------------------------------------===//
 495 //  MachineConstantPool implementation
 496 //===----------------------------------------------------------------------===//
 497
 498 const Type *MachineConstantPoolEntry::getType() const {
 499   if (isMachineConstantPoolEntry())
 500     return Val.MachineCPVal->getType();
 501   return Val.ConstVal->getType();
 502 }
 503
 504
 505 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
 506   if (isMachineConstantPoolEntry())
 507     return Val.MachineCPVal->getRelocationInfo();
 508   return Val.ConstVal->getRelocationInfo();
 509 }
 510
 511 MachineConstantPool::~MachineConstantPool() {
 512   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 513     if (Constants[i].isMachineConstantPoolEntry())
 514       delete Constants[i].Val.MachineCPVal;
 515 }
 516
 517 /// getConstantPoolIndex - Create a new entry in the constant pool or return
 518 /// an existing one.  User must specify the log2 of the minimum required
 519 /// alignment for the object.
 520 ///
 521 unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
 522                                                    unsigned Alignment) {
 523   assert(Alignment && "Alignment must be specified!");
 524   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 525
 526   // Check to see if we already have this constant.
 527   //
 528   // FIXME, this could be made much more efficient for large constant pools.
 529   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 530     if (Constants[i].Val.ConstVal == C &&
 531         (Constants[i].getAlignment() & (Alignment - 1)) == 0)
 532       return i;
 533
 534   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
 535   return Constants.size()-1;
 536 }
 537
 538 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
 539                                                    unsigned Alignment) {
 540   assert(Alignment && "Alignment must be specified!");
 541   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 542
 543   // Check to see if we already have this constant.
 544   //
 545   // FIXME, this could be made much more efficient for large constant pools.
 546   int Idx = V->getExistingMachineCPValue(this, Alignment);
 547   if (Idx != -1)
 548     return (unsigned)Idx;
 549
 550   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
 551   return Constants.size()-1;
 552 }
 553
 554 void MachineConstantPool::print(raw_ostream &OS) const {
 555   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
 556     OS << "  <cp#" << i << "> is";
 557     if (Constants[i].isMachineConstantPoolEntry())
 558       Constants[i].Val.MachineCPVal->print(OS);
 559     else
 560       OS << *(Value*)Constants[i].Val.ConstVal;
 561     OS << " , alignment=" << Constants[i].getAlignment();
 562     OS << "\n";
 563   }
 564 }
 565
 566 void MachineConstantPool::dump() const { print(errs()); }