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/MachineFunctionPass.h"
  23 #include "llvm/CodeGen/MachineFrameInfo.h"
  24 #include "llvm/CodeGen/MachineInstr.h"
  25 #include "llvm/CodeGen/MachineJumpTableInfo.h"
  26 #include "llvm/CodeGen/MachineRegisterInfo.h"
  27 #include "llvm/CodeGen/Passes.h"
  28 #include "llvm/Target/TargetData.h"
  29 #include "llvm/Target/TargetLowering.h"
  30 #include "llvm/Target/TargetMachine.h"
  31 #include "llvm/Target/TargetFrameInfo.h"
  32 #include "llvm/Support/Compiler.h"
  33 #include "llvm/Support/GraphWriter.h"
  34 #include "llvm/Support/raw_ostream.h"
  35 #include <fstream>
  36 #include <sstream>
  37 using namespace llvm;
  38
  39 namespace {
  40   struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
  41     static char ID;
  42
  43     std::ostream *OS;
  44     const std::string Banner;
  45
  46     Printer (std::ostream *os, const std::string &banner)
  47       : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
  48
  49     const char *getPassName() const { return "MachineFunction Printer"; }
  50
  51     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  52       AU.setPreservesAll();
  53       MachineFunctionPass::getAnalysisUsage(AU);
  54     }
  55
  56     bool runOnMachineFunction(MachineFunction &MF) {
  57       (*OS) << Banner;
  58       MF.print (*OS);
  59       return false;
  60     }
  61   };
  62   char Printer::ID = 0;
  63 }
  64
  65 /// Returns a newly-created MachineFunction Printer pass. The default banner is
  66 /// empty.
  67 ///
  68 FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
  69                                                      const std::string &Banner){
  70   return new Printer(OS, Banner);
  71 }
  72
  73 //===---------------------------------------------------------------------===//
  74 // MachineFunction implementation
  75 //===---------------------------------------------------------------------===//
  76
  77 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
  78   MBB->getParent()->DeleteMachineBasicBlock(MBB);
  79 }
  80
  81 MachineFunction::MachineFunction(Function *F,
  82                                  const TargetMachine &TM)
  83   : Fn(F), Target(TM) {
  84   if (TM.getRegisterInfo())
  85     RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
  86                   MachineRegisterInfo(*TM.getRegisterInfo());
  87   else
  88     RegInfo = 0;
  89   MFInfo = 0;
  90   FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
  91                   MachineFrameInfo(*TM.getFrameInfo());
  92   ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
  93                      MachineConstantPool(TM.getTargetData());
  94   Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
  95
  96   CallSiteIndex = 0;
  97   MaxCallSiteIndex = 0;
  98
  99   // Set up jump table.
 100   const TargetData &TD = *TM.getTargetData();
 101   bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
 102   unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
 103   unsigned TyAlignment = IsPic ?
 104                        TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
 105                                : TD.getPointerABIAlignment();
 106   JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
 107                       MachineJumpTableInfo(EntrySize, TyAlignment);
 108 }
 109
 110 MachineFunction::~MachineFunction() {
 111   BasicBlocks.clear();
 112   InstructionRecycler.clear(Allocator);
 113   BasicBlockRecycler.clear(Allocator);
 114   if (RegInfo) {
 115     RegInfo->~MachineRegisterInfo();
 116     Allocator.Deallocate(RegInfo);
 117   }
 118   if (MFInfo) {
 119     MFInfo->~MachineFunctionInfo();
 120     Allocator.Deallocate(MFInfo);
 121   }
 122   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
 123   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
 124   JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
 125 }
 126
 127
 128 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
 129 /// recomputes them.  This guarantees that the MBB numbers are sequential,
 130 /// dense, and match the ordering of the blocks within the function.  If a
 131 /// specific MachineBasicBlock is specified, only that block and those after
 132 /// it are renumbered.
 133 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 134   if (empty()) { MBBNumbering.clear(); return; }
 135   MachineFunction::iterator MBBI, E = end();
 136   if (MBB == 0)
 137     MBBI = begin();
 138   else
 139     MBBI = MBB;
 140
 141   // Figure out the block number this should have.
 142   unsigned BlockNo = 0;
 143   if (MBBI != begin())
 144     BlockNo = prior(MBBI)->getNumber()+1;
 145
 146   for (; MBBI != E; ++MBBI, ++BlockNo) {
 147     if (MBBI->getNumber() != (int)BlockNo) {
 148       // Remove use of the old number.
 149       if (MBBI->getNumber() != -1) {
 150         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 151                "MBB number mismatch!");
 152         MBBNumbering[MBBI->getNumber()] = 0;
 153       }
 154
 155       // If BlockNo is already taken, set that block's number to -1.
 156       if (MBBNumbering[BlockNo])
 157         MBBNumbering[BlockNo]->setNumber(-1);
 158
 159       MBBNumbering[BlockNo] = MBBI;
 160       MBBI->setNumber(BlockNo);
 161     }
 162   }
 163
 164   // Okay, all the blocks are renumbered.  If we have compactified the block
 165   // numbering, shrink MBBNumbering now.
 166   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 167   MBBNumbering.resize(BlockNo);
 168 }
 169
 170 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
 171 /// of `new MachineInstr'.
 172 ///
 173 MachineInstr *
 174 MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
 175                                     DebugLoc DL, bool NoImp) {
 176   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 177     MachineInstr(TID, DL, NoImp);
 178 }
 179
 180 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
 181 /// 'Orig' instruction, identical in all ways except the the instruction
 182 /// has no parent, prev, or next.
 183 ///
 184 MachineInstr *
 185 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 186   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 187              MachineInstr(*this, *Orig);
 188 }
 189
 190 /// DeleteMachineInstr - Delete the given MachineInstr.
 191 ///
 192 void
 193 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 194   // Clear the instructions memoperands. This must be done manually because
 195   // the instruction's parent pointer is now null, so it can't properly
 196   // deallocate them on its own.
 197   MI->clearMemOperands(*this);
 198
 199   MI->~MachineInstr();
 200   InstructionRecycler.Deallocate(Allocator, MI);
 201 }
 202
 203 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
 204 /// instead of `new MachineBasicBlock'.
 205 ///
 206 MachineBasicBlock *
 207 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 208   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 209              MachineBasicBlock(*this, bb);
 210 }
 211
 212 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
 213 ///
 214 void
 215 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 216   assert(MBB->getParent() == this && "MBB parent mismatch!");
 217   MBB->~MachineBasicBlock();
 218   BasicBlockRecycler.Deallocate(Allocator, MBB);
 219 }
 220
 221 void MachineFunction::dump() const {
 222   print(*cerr.stream());
 223 }
 224
 225 void MachineFunction::print(std::ostream &OS,
 226                             const PrefixPrinter &prefix) const {
 227   OS << "# Machine code for " << Fn->getNameStr () << "():\n";
 228
 229   // Print Frame Information
 230   FrameInfo->print(*this, OS);
 231
 232   // Print JumpTable Information
 233   JumpTableInfo->print(OS);
 234
 235   // Print Constant Pool
 236   {
 237     raw_os_ostream OSS(OS);
 238     ConstantPool->print(OSS);
 239   }
 240
 241   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
 242
 243   if (RegInfo && !RegInfo->livein_empty()) {
 244     OS << "Live Ins:";
 245     for (MachineRegisterInfo::livein_iterator
 246          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 247       if (TRI)
 248         OS << " " << TRI->getName(I->first);
 249       else
 250         OS << " Reg #" << I->first;
 251
 252       if (I->second)
 253         OS << " in VR#" << I->second << " ";
 254     }
 255     OS << "\n";
 256   }
 257   if (RegInfo && !RegInfo->liveout_empty()) {
 258     OS << "Live Outs:";
 259     for (MachineRegisterInfo::liveout_iterator
 260          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
 261       if (TRI)
 262         OS << " " << TRI->getName(*I);
 263       else
 264         OS << " Reg #" << *I;
 265     OS << "\n";
 266   }
 267
 268   for (const_iterator BB = begin(); BB != end(); ++BB) {
 269     prefix(OS, *BB);
 270     BB->print(OS, prefix);
 271   }
 272
 273   OS << "\n# End machine code for " << Fn->getNameStr () << "().\n\n";
 274 }
 275
 276 namespace llvm {
 277   template<>
 278   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 279     static std::string getGraphName(const MachineFunction *F) {
 280       return "CFG for '" + F->getFunction()->getNameStr() + "' function";
 281     }
 282
 283     static std::string getNodeLabel(const MachineBasicBlock *Node,
 284                                     const MachineFunction *Graph,
 285                                     bool ShortNames) {
 286       if (ShortNames && Node->getBasicBlock() &&
 287           !Node->getBasicBlock()->getName().empty())
 288         return Node->getBasicBlock()->getNameStr() + ":";
 289
 290       std::ostringstream Out;
 291       if (ShortNames) {
 292         Out << Node->getNumber() << ':';
 293         return Out.str();
 294       }
 295
 296       Node->print(Out);
 297
 298       std::string OutStr = Out.str();
 299       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 300
 301       // Process string output to make it nicer...
 302       for (unsigned i = 0; i != OutStr.length(); ++i)
 303         if (OutStr[i] == '\n') {                            // Left justify
 304           OutStr[i] = '\\';
 305           OutStr.insert(OutStr.begin()+i+1, 'l');
 306         }
 307       return OutStr;
 308     }
 309   };
 310 }
 311
 312 void MachineFunction::viewCFG() const
 313 {
 314 #ifndef NDEBUG
 315   ViewGraph(this, "mf" + getFunction()->getNameStr());
 316 #else
 317   cerr << "SelectionDAG::viewGraph is only available in debug builds on "
 318        << "systems with Graphviz or gv!\n";
 319 #endif // NDEBUG
 320 }
 321
 322 void MachineFunction::viewCFGOnly() const
 323 {
 324 #ifndef NDEBUG
 325   ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
 326 #else
 327   cerr << "SelectionDAG::viewGraph is only available in debug builds on "
 328        << "systems with Graphviz or gv!\n";
 329 #endif // NDEBUG
 330 }
 331
 332 /// addLiveIn - Add the specified physical register as a live-in value and
 333 /// create a corresponding virtual register for it.
 334 unsigned MachineFunction::addLiveIn(unsigned PReg,
 335                                     const TargetRegisterClass *RC) {
 336   assert(RC->contains(PReg) && "Not the correct regclass!");
 337   unsigned VReg = getRegInfo().createVirtualRegister(RC);
 338   getRegInfo().addLiveIn(PReg, VReg);
 339   return VReg;
 340 }
 341
 342 /// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
 343 /// source file, line, and column. If none currently exists, create a new
 344 /// DebugLocTuple, and insert it into the DebugIdMap.
 345 unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
 346                                                 unsigned Line, unsigned Col) {
 347   DebugLocTuple Tuple(CompileUnit, Line, Col);
 348   DenseMap<DebugLocTuple, unsigned>::iterator II
 349     = DebugLocInfo.DebugIdMap.find(Tuple);
 350   if (II != DebugLocInfo.DebugIdMap.end())
 351     return II->second;
 352   // Add a new tuple.
 353   unsigned Id = DebugLocInfo.DebugLocations.size();
 354   DebugLocInfo.DebugLocations.push_back(Tuple);
 355   DebugLocInfo.DebugIdMap[Tuple] = Id;
 356   return Id;
 357 }
 358
 359 /// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
 360 DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
 361   unsigned Idx = DL.getIndex();
 362   assert(Idx < DebugLocInfo.DebugLocations.size() &&
 363          "Invalid index into debug locations!");
 364   return DebugLocInfo.DebugLocations[Idx];
 365 }
 366
 367 //===----------------------------------------------------------------------===//
 368 //  MachineFrameInfo implementation
 369 //===----------------------------------------------------------------------===//
 370
 371 /// CreateFixedObject - Create a new object at a fixed location on the stack.
 372 /// All fixed objects should be created before other objects are created for
 373 /// efficiency. By default, fixed objects are immutable. This returns an
 374 /// index with a negative value.
 375 ///
 376 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
 377                                         bool Immutable) {
 378   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
 379   Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
 380   return -++NumFixedObjects;
 381 }
 382
 383
 384 BitVector
 385 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
 386   assert(MBB && "MBB must be valid");
 387   const MachineFunction *MF = MBB->getParent();
 388   assert(MF && "MBB must be part of a MachineFunction");
 389   const TargetMachine &TM = MF->getTarget();
 390   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
 391   BitVector BV(TRI->getNumRegs());
 392
 393   // Before CSI is calculated, no registers are considered pristine. They can be
 394   // freely used and PEI will make sure they are saved.
 395   if (!isCalleeSavedInfoValid())
 396     return BV;
 397
 398   for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
 399     BV.set(*CSR);
 400
 401   // The entry MBB always has all CSRs pristine.
 402   if (MBB == &MF->front())
 403     return BV;
 404
 405   // On other MBBs the saved CSRs are not pristine.
 406   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
 407   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
 408          E = CSI.end(); I != E; ++I)
 409     BV.reset(I->getReg());
 410
 411   return BV;
 412 }
 413
 414
 415 void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
 416   const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
 417   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
 418
 419   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
 420     const StackObject &SO = Objects[i];
 421     OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
 422     if (SO.Size == ~0ULL) {
 423       OS << "dead\n";
 424       continue;
 425     }
 426     if (SO.Size == 0)
 427       OS << "variable sized";
 428     else
 429       OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
 430     OS << " alignment is " << SO.Alignment << " byte"
 431        << (SO.Alignment != 1 ? "s," : ",");
 432
 433     if (i < NumFixedObjects)
 434       OS << " fixed";
 435     if (i < NumFixedObjects || SO.SPOffset != -1) {
 436       int64_t Off = SO.SPOffset - ValOffset;
 437       OS << " at location [SP";
 438       if (Off > 0)
 439         OS << "+" << Off;
 440       else if (Off < 0)
 441         OS << Off;
 442       OS << "]";
 443     }
 444     OS << "\n";
 445   }
 446
 447   if (HasVarSizedObjects)
 448     OS << "  Stack frame contains variable sized objects\n";
 449 }
 450
 451 void MachineFrameInfo::dump(const MachineFunction &MF) const {
 452   print(MF, *cerr.stream());
 453 }
 454
 455 //===----------------------------------------------------------------------===//
 456 //  MachineJumpTableInfo implementation
 457 //===----------------------------------------------------------------------===//
 458
 459 /// getJumpTableIndex - Create a new jump table entry in the jump table info
 460 /// or return an existing one.
 461 ///
 462 unsigned MachineJumpTableInfo::getJumpTableIndex(
 463                                const std::vector<MachineBasicBlock*> &DestBBs) {
 464   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 465   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
 466     if (JumpTables[i].MBBs == DestBBs)
 467       return i;
 468
 469   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 470   return JumpTables.size()-1;
 471 }
 472
 473 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
 474 /// the jump tables to branch to New instead.
 475 bool
 476 MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 477                                              MachineBasicBlock *New) {
 478   assert(Old != New && "Not making a change?");
 479   bool MadeChange = false;
 480   for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
 481     MachineJumpTableEntry &JTE = JumpTables[i];
 482     for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 483       if (JTE.MBBs[j] == Old) {
 484         JTE.MBBs[j] = New;
 485         MadeChange = true;
 486       }
 487   }
 488   return MadeChange;
 489 }
 490
 491 void MachineJumpTableInfo::print(std::ostream &OS) const {
 492   // FIXME: this is lame, maybe we could print out the MBB numbers or something
 493   // like {1, 2, 4, 5, 3, 0}
 494   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 495     OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
 496        << " entries\n";
 497   }
 498 }
 499
 500 void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
 501
 502
 503 //===----------------------------------------------------------------------===//
 504 //  MachineConstantPool implementation
 505 //===----------------------------------------------------------------------===//
 506
 507 const Type *MachineConstantPoolEntry::getType() const {
 508   if (isMachineConstantPoolEntry())
 509     return Val.MachineCPVal->getType();
 510   return Val.ConstVal->getType();
 511 }
 512
 513
 514 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
 515   if (isMachineConstantPoolEntry())
 516     return Val.MachineCPVal->getRelocationInfo();
 517   return Val.ConstVal->getRelocationInfo();
 518 }
 519
 520 MachineConstantPool::~MachineConstantPool() {
 521   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 522     if (Constants[i].isMachineConstantPoolEntry())
 523       delete Constants[i].Val.MachineCPVal;
 524 }
 525
 526 /// getConstantPoolIndex - Create a new entry in the constant pool or return
 527 /// an existing one.  User must specify the log2 of the minimum required
 528 /// alignment for the object.
 529 ///
 530 unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
 531                                                    unsigned Alignment) {
 532   assert(Alignment && "Alignment must be specified!");
 533   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 534
 535   // Check to see if we already have this constant.
 536   //
 537   // FIXME, this could be made much more efficient for large constant pools.
 538   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 539     if (Constants[i].Val.ConstVal == C &&
 540         (Constants[i].getAlignment() & (Alignment - 1)) == 0)
 541       return i;
 542
 543   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
 544   return Constants.size()-1;
 545 }
 546
 547 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
 548                                                    unsigned Alignment) {
 549   assert(Alignment && "Alignment must be specified!");
 550   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
 551
 552   // Check to see if we already have this constant.
 553   //
 554   // FIXME, this could be made much more efficient for large constant pools.
 555   int Idx = V->getExistingMachineCPValue(this, Alignment);
 556   if (Idx != -1)
 557     return (unsigned)Idx;
 558
 559   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
 560   return Constants.size()-1;
 561 }
 562
 563 void MachineConstantPool::print(raw_ostream &OS) const {
 564   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
 565     OS << "  <cp#" << i << "> is";
 566     if (Constants[i].isMachineConstantPoolEntry())
 567       Constants[i].Val.MachineCPVal->print(OS);
 568     else
 569       OS << *(Value*)Constants[i].Val.ConstVal;
 570     OS << " , alignment=" << Constants[i].getAlignment();
 571     OS << "\n";
 572   }
 573 }
 574
 575 void MachineConstantPool::dump() const { print(errs()); }