MachineFunction.cpp revision 4a0f08c5fc14d840e4e411fade036f1cd815b795 
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>
37using namespace llvm;
38
39namespace {
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///
68FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
69                                                     const std::string &Banner){
70  return new Printer(OS, Banner);
71}
72
73//===---------------------------------------------------------------------===//
74// MachineFunction implementation
75//===---------------------------------------------------------------------===//
76
77void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
78  MBB->getParent()->DeleteMachineBasicBlock(MBB);
79}
80
81MachineFunction::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 ? TD.getABITypeAlignment(Type::Int32Ty)
104                               : TD.getPointerABIAlignment();
105  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
106                      MachineJumpTableInfo(EntrySize, TyAlignment);
107}
108
109MachineFunction::~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.
132void 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///
172MachineInstr *
173MachineFunction::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///
183MachineInstr *
184MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
185  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
186             MachineInstr(*this, *Orig);
187}
188
189/// DeleteMachineInstr - Delete the given MachineInstr.
190///
191void
192MachineFunction::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///
205MachineBasicBlock *
206MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
207  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
208             MachineBasicBlock(*this, bb);
209}
210
211/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
212///
213void
214MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
215  assert(MBB->getParent() == this && "MBB parent mismatch!");
216  MBB->~MachineBasicBlock();
217  BasicBlockRecycler.Deallocate(Allocator, MBB);
218}
219
220void MachineFunction::dump() const {
221  print(*cerr.stream());
222}
223
224void MachineFunction::print(std::ostream &OS,
225                            const PrefixPrinter &prefix) const {
226  OS << "# Machine code for " << Fn->getNameStr () << "():\n";
227
228  // Print Frame Information
229  FrameInfo->print(*this, OS);
230
231  // Print JumpTable Information
232  JumpTableInfo->print(OS);
233
234  // Print Constant Pool
235  {
236    raw_os_ostream OSS(OS);
237    ConstantPool->print(OSS);
238  }
239
240  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
241
242  if (RegInfo && !RegInfo->livein_empty()) {
243    OS << "Live Ins:";
244    for (MachineRegisterInfo::livein_iterator
245         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
246      if (TRI)
247        OS << " " << TRI->getName(I->first);
248      else
249        OS << " Reg #" << I->first;
250
251      if (I->second)
252        OS << " in VR#" << I->second << " ";
253    }
254    OS << "\n";
255  }
256  if (RegInfo && !RegInfo->liveout_empty()) {
257    OS << "Live Outs:";
258    for (MachineRegisterInfo::liveout_iterator
259         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
260      if (TRI)
261        OS << " " << TRI->getName(*I);
262      else
263        OS << " Reg #" << *I;
264    OS << "\n";
265  }
266
267  for (const_iterator BB = begin(); BB != end(); ++BB) {
268    prefix(OS, *BB);
269    BB->print(OS, prefix);
270  }
271
272  OS << "\n# End machine code for " << Fn->getNameStr () << "().\n\n";
273}
274
275namespace llvm {
276  template<>
277  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
278    static std::string getGraphName(const MachineFunction *F) {
279      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
280    }
281
282    static std::string getNodeLabel(const MachineBasicBlock *Node,
283                                    const MachineFunction *Graph,
284                                    bool ShortNames) {
285      if (ShortNames && Node->getBasicBlock() &&
286          !Node->getBasicBlock()->getName().empty())
287        return Node->getBasicBlock()->getNameStr() + ":";
288
289      std::ostringstream Out;
290      if (ShortNames) {
291        Out << Node->getNumber() << ':';
292        return Out.str();
293      }
294
295      Node->print(Out);
296
297      std::string OutStr = Out.str();
298      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
299
300      // Process string output to make it nicer...
301      for (unsigned i = 0; i != OutStr.length(); ++i)
302        if (OutStr[i] == '\n') {                            // Left justify
303          OutStr[i] = '\\';
304          OutStr.insert(OutStr.begin()+i+1, 'l');
305        }
306      return OutStr;
307    }
308  };
309}
310
311void MachineFunction::viewCFG() const
312{
313#ifndef NDEBUG
314  ViewGraph(this, "mf" + getFunction()->getNameStr());
315#else
316  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
317       << "systems with Graphviz or gv!\n";
318#endif // NDEBUG
319}
320
321void MachineFunction::viewCFGOnly() const
322{
323#ifndef NDEBUG
324  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
325#else
326  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
327       << "systems with Graphviz or gv!\n";
328#endif // NDEBUG
329}
330
331/// addLiveIn - Add the specified physical register as a live-in value and
332/// create a corresponding virtual register for it.
333unsigned MachineFunction::addLiveIn(unsigned PReg,
334                                    const TargetRegisterClass *RC) {
335  assert(RC->contains(PReg) && "Not the correct regclass!");
336  unsigned VReg = getRegInfo().createVirtualRegister(RC);
337  getRegInfo().addLiveIn(PReg, VReg);
338  return VReg;
339}
340
341/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
342/// source file, line, and column. If none currently exists, create a new
343/// DebugLocTuple, and insert it into the DebugIdMap.
344unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
345                                                unsigned Line, unsigned Col) {
346  DebugLocTuple Tuple(CompileUnit, Line, Col);
347  DenseMap<DebugLocTuple, unsigned>::iterator II
348    = DebugLocInfo.DebugIdMap.find(Tuple);
349  if (II != DebugLocInfo.DebugIdMap.end())
350    return II->second;
351  // Add a new tuple.
352  unsigned Id = DebugLocInfo.DebugLocations.size();
353  DebugLocInfo.DebugLocations.push_back(Tuple);
354  DebugLocInfo.DebugIdMap[Tuple] = Id;
355  return Id;
356}
357
358/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
359DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
360  unsigned Idx = DL.getIndex();
361  assert(Idx < DebugLocInfo.DebugLocations.size() &&
362         "Invalid index into debug locations!");
363  return DebugLocInfo.DebugLocations[Idx];
364}
365
366//===----------------------------------------------------------------------===//
367//  MachineFrameInfo implementation
368//===----------------------------------------------------------------------===//
369
370/// CreateFixedObject - Create a new object at a fixed location on the stack.
371/// All fixed objects should be created before other objects are created for
372/// efficiency. By default, fixed objects are immutable. This returns an
373/// index with a negative value.
374///
375int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
376                                        bool Immutable) {
377  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
378  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
379  return -++NumFixedObjects;
380}
381
382
383BitVector
384MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
385  assert(MBB && "MBB must be valid");
386  const MachineFunction *MF = MBB->getParent();
387  assert(MF && "MBB must be part of a MachineFunction");
388  const TargetMachine &TM = MF->getTarget();
389  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
390  BitVector BV(TRI->getNumRegs());
391
392  // Before CSI is calculated, no registers are considered pristine. They can be
393  // freely used and PEI will make sure they are saved.
394  if (!isCalleeSavedInfoValid())
395    return BV;
396
397  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
398    BV.set(*CSR);
399
400  // The entry MBB always has all CSRs pristine.
401  if (MBB == &MF->front())
402    return BV;
403
404  // On other MBBs the saved CSRs are not pristine.
405  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
406  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
407         E = CSI.end(); I != E; ++I)
408    BV.reset(I->getReg());
409
410  return BV;
411}
412
413
414void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
415  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
416  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
417
418  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
419    const StackObject &SO = Objects[i];
420    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
421    if (SO.Size == ~0ULL) {
422      OS << "dead\n";
423      continue;
424    }
425    if (SO.Size == 0)
426      OS << "variable sized";
427    else
428      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
429    OS << " alignment is " << SO.Alignment << " byte"
430       << (SO.Alignment != 1 ? "s," : ",");
431
432    if (i < NumFixedObjects)
433      OS << " fixed";
434    if (i < NumFixedObjects || SO.SPOffset != -1) {
435      int64_t Off = SO.SPOffset - ValOffset;
436      OS << " at location [SP";
437      if (Off > 0)
438        OS << "+" << Off;
439      else if (Off < 0)
440        OS << Off;
441      OS << "]";
442    }
443    OS << "\n";
444  }
445
446  if (HasVarSizedObjects)
447    OS << "  Stack frame contains variable sized objects\n";
448}
449
450void MachineFrameInfo::dump(const MachineFunction &MF) const {
451  print(MF, *cerr.stream());
452}
453
454//===----------------------------------------------------------------------===//
455//  MachineJumpTableInfo implementation
456//===----------------------------------------------------------------------===//
457
458/// getJumpTableIndex - Create a new jump table entry in the jump table info
459/// or return an existing one.
460///
461unsigned MachineJumpTableInfo::getJumpTableIndex(
462                               const std::vector<MachineBasicBlock*> &DestBBs) {
463  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
464  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
465    if (JumpTables[i].MBBs == DestBBs)
466      return i;
467
468  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
469  return JumpTables.size()-1;
470}
471
472/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
473/// the jump tables to branch to New instead.
474bool
475MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
476                                             MachineBasicBlock *New) {
477  assert(Old != New && "Not making a change?");
478  bool MadeChange = false;
479  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
480    MachineJumpTableEntry &JTE = JumpTables[i];
481    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
482      if (JTE.MBBs[j] == Old) {
483        JTE.MBBs[j] = New;
484        MadeChange = true;
485      }
486  }
487  return MadeChange;
488}
489
490void MachineJumpTableInfo::print(std::ostream &OS) const {
491  // FIXME: this is lame, maybe we could print out the MBB numbers or something
492  // like {1, 2, 4, 5, 3, 0}
493  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
494    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
495       << " entries\n";
496  }
497}
498
499void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
500
501
502//===----------------------------------------------------------------------===//
503//  MachineConstantPool implementation
504//===----------------------------------------------------------------------===//
505
506const Type *MachineConstantPoolEntry::getType() const {
507  if (isMachineConstantPoolEntry())
508    return Val.MachineCPVal->getType();
509  return Val.ConstVal->getType();
510}
511
512
513unsigned MachineConstantPoolEntry::getRelocationInfo() const {
514  if (isMachineConstantPoolEntry())
515    return Val.MachineCPVal->getRelocationInfo();
516  return Val.ConstVal->getRelocationInfo();
517}
518
519MachineConstantPool::~MachineConstantPool() {
520  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
521    if (Constants[i].isMachineConstantPoolEntry())
522      delete Constants[i].Val.MachineCPVal;
523}
524
525/// getConstantPoolIndex - Create a new entry in the constant pool or return
526/// an existing one.  User must specify the log2 of the minimum required
527/// alignment for the object.
528///
529unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
530                                                   unsigned Alignment) {
531  assert(Alignment && "Alignment must be specified!");
532  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
533
534  // Check to see if we already have this constant.
535  //
536  // FIXME, this could be made much more efficient for large constant pools.
537  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
538    if (Constants[i].Val.ConstVal == C &&
539        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
540      return i;
541
542  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
543  return Constants.size()-1;
544}
545
546unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
547                                                   unsigned Alignment) {
548  assert(Alignment && "Alignment must be specified!");
549  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
550
551  // Check to see if we already have this constant.
552  //
553  // FIXME, this could be made much more efficient for large constant pools.
554  int Idx = V->getExistingMachineCPValue(this, Alignment);
555  if (Idx != -1)
556    return (unsigned)Idx;
557
558  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
559  return Constants.size()-1;
560}
561
562void MachineConstantPool::print(raw_ostream &OS) const {
563  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
564    OS << "  <cp#" << i << "> is";
565    if (Constants[i].isMachineConstantPoolEntry())
566      Constants[i].Val.MachineCPVal->print(OS);
567    else
568      OS << *(Value*)Constants[i].Val.ConstVal;
569    OS << " , alignment=" << Constants[i].getAlignment();
570    OS << "\n";
571  }
572}
573
574void MachineConstantPool::dump() const { print(errs()); }
575