MachineFunction.cpp revision b214eb923422fa6850fba5e7c36a3482a4ffb871 
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#include <fstream>
37#include <sstream>
38using namespace llvm;
39
40namespace {
41  struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
42    static char ID;
43
44    std::ostream *OS;
45    const std::string Banner;
46
47    Printer (std::ostream *os, const std::string &banner)
48      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
49
50    const char *getPassName() const { return "MachineFunction Printer"; }
51
52    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
53      AU.setPreservesAll();
54      MachineFunctionPass::getAnalysisUsage(AU);
55    }
56
57    bool runOnMachineFunction(MachineFunction &MF) {
58      (*OS) << Banner;
59      MF.print (*OS);
60      return false;
61    }
62  };
63  char Printer::ID = 0;
64}
65
66/// Returns a newly-created MachineFunction Printer pass. The default banner is
67/// empty.
68///
69FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
70                                                     const std::string &Banner){
71  return new Printer(OS, Banner);
72}
73
74//===---------------------------------------------------------------------===//
75// MachineFunction implementation
76//===---------------------------------------------------------------------===//
77
78void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
79  MBB->getParent()->DeleteMachineBasicBlock(MBB);
80}
81
82MachineFunction::MachineFunction(Function *F,
83                                 const TargetMachine &TM)
84  : Fn(F), Target(TM) {
85  if (TM.getRegisterInfo())
86    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
87                  MachineRegisterInfo(*TM.getRegisterInfo());
88  else
89    RegInfo = 0;
90  MFInfo = 0;
91  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
92                  MachineFrameInfo(*TM.getFrameInfo());
93  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
94                     MachineConstantPool(TM.getTargetData());
95  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
96
97  // Set up jump table.
98  const TargetData &TD = *TM.getTargetData();
99  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
100  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
101  unsigned TyAlignment = IsPic ?
102                       TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
103                               : TD.getPointerABIAlignment();
104  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
105                      MachineJumpTableInfo(EntrySize, TyAlignment);
106}
107
108MachineFunction::~MachineFunction() {
109  BasicBlocks.clear();
110  InstructionRecycler.clear(Allocator);
111  BasicBlockRecycler.clear(Allocator);
112  if (RegInfo) {
113    RegInfo->~MachineRegisterInfo();
114    Allocator.Deallocate(RegInfo);
115  }
116  if (MFInfo) {
117    MFInfo->~MachineFunctionInfo();
118    Allocator.Deallocate(MFInfo);
119  }
120  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
121  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
122  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
123}
124
125
126/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
127/// recomputes them.  This guarantees that the MBB numbers are sequential,
128/// dense, and match the ordering of the blocks within the function.  If a
129/// specific MachineBasicBlock is specified, only that block and those after
130/// it are renumbered.
131void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
132  if (empty()) { MBBNumbering.clear(); return; }
133  MachineFunction::iterator MBBI, E = end();
134  if (MBB == 0)
135    MBBI = begin();
136  else
137    MBBI = MBB;
138
139  // Figure out the block number this should have.
140  unsigned BlockNo = 0;
141  if (MBBI != begin())
142    BlockNo = prior(MBBI)->getNumber()+1;
143
144  for (; MBBI != E; ++MBBI, ++BlockNo) {
145    if (MBBI->getNumber() != (int)BlockNo) {
146      // Remove use of the old number.
147      if (MBBI->getNumber() != -1) {
148        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
149               "MBB number mismatch!");
150        MBBNumbering[MBBI->getNumber()] = 0;
151      }
152
153      // If BlockNo is already taken, set that block's number to -1.
154      if (MBBNumbering[BlockNo])
155        MBBNumbering[BlockNo]->setNumber(-1);
156
157      MBBNumbering[BlockNo] = MBBI;
158      MBBI->setNumber(BlockNo);
159    }
160  }
161
162  // Okay, all the blocks are renumbered.  If we have compactified the block
163  // numbering, shrink MBBNumbering now.
164  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
165  MBBNumbering.resize(BlockNo);
166}
167
168/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
169/// of `new MachineInstr'.
170///
171MachineInstr *
172MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
173                                    DebugLoc DL, bool NoImp) {
174  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
175    MachineInstr(TID, DL, NoImp);
176}
177
178/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
179/// 'Orig' instruction, identical in all ways except the the instruction
180/// has no parent, prev, or next.
181///
182MachineInstr *
183MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
184  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
185             MachineInstr(*this, *Orig);
186}
187
188/// DeleteMachineInstr - Delete the given MachineInstr.
189///
190void
191MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
192  // Clear the instructions memoperands. This must be done manually because
193  // the instruction's parent pointer is now null, so it can't properly
194  // deallocate them on its own.
195  MI->clearMemOperands(*this);
196
197  MI->~MachineInstr();
198  InstructionRecycler.Deallocate(Allocator, MI);
199}
200
201/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
202/// instead of `new MachineBasicBlock'.
203///
204MachineBasicBlock *
205MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
206  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
207             MachineBasicBlock(*this, bb);
208}
209
210/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
211///
212void
213MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
214  assert(MBB->getParent() == this && "MBB parent mismatch!");
215  MBB->~MachineBasicBlock();
216  BasicBlockRecycler.Deallocate(Allocator, MBB);
217}
218
219void MachineFunction::dump() const {
220  print(*cerr.stream());
221}
222
223void MachineFunction::print(std::ostream &OS,
224                            const PrefixPrinter &prefix) const {
225  OS << "# Machine code for " << Fn->getNameStr () << "():\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  {
235    raw_os_ostream OSS(OS);
236    ConstantPool->print(OSS);
237  }
238
239  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
240
241  if (RegInfo && !RegInfo->livein_empty()) {
242    OS << "Live Ins:";
243    for (MachineRegisterInfo::livein_iterator
244         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
245      if (TRI)
246        OS << " " << TRI->getName(I->first);
247      else
248        OS << " Reg #" << I->first;
249
250      if (I->second)
251        OS << " in VR#" << I->second << " ";
252    }
253    OS << "\n";
254  }
255  if (RegInfo && !RegInfo->liveout_empty()) {
256    OS << "Live Outs:";
257    for (MachineRegisterInfo::liveout_iterator
258         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
259      if (TRI)
260        OS << " " << TRI->getName(*I);
261      else
262        OS << " Reg #" << *I;
263    OS << "\n";
264  }
265
266  for (const_iterator BB = begin(); BB != end(); ++BB) {
267    prefix(OS, *BB);
268    BB->print(OS, prefix);
269  }
270
271  OS << "\n# End machine code for " << Fn->getNameStr () << "().\n\n";
272}
273
274namespace llvm {
275  template<>
276  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
277    static std::string getGraphName(const MachineFunction *F) {
278      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
279    }
280
281    static std::string getNodeLabel(const MachineBasicBlock *Node,
282                                    const MachineFunction *Graph,
283                                    bool ShortNames) {
284      if (ShortNames && Node->getBasicBlock() &&
285          !Node->getBasicBlock()->getName().empty())
286        return Node->getBasicBlock()->getNameStr() + ":";
287
288      std::ostringstream Out;
289      if (ShortNames) {
290        Out << Node->getNumber() << ':';
291        return Out.str();
292      }
293
294      Node->print(Out);
295
296      std::string OutStr = Out.str();
297      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
298
299      // Process string output to make it nicer...
300      for (unsigned i = 0; i != OutStr.length(); ++i)
301        if (OutStr[i] == '\n') {                            // Left justify
302          OutStr[i] = '\\';
303          OutStr.insert(OutStr.begin()+i+1, 'l');
304        }
305      return OutStr;
306    }
307  };
308}
309
310void MachineFunction::viewCFG() const
311{
312#ifndef NDEBUG
313  ViewGraph(this, "mf" + getFunction()->getNameStr());
314#else
315  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
316       << "systems with Graphviz or gv!\n";
317#endif // NDEBUG
318}
319
320void MachineFunction::viewCFGOnly() const
321{
322#ifndef NDEBUG
323  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
324#else
325  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
326       << "systems with Graphviz or gv!\n";
327#endif // NDEBUG
328}
329
330/// addLiveIn - Add the specified physical register as a live-in value and
331/// create a corresponding virtual register for it.
332unsigned MachineFunction::addLiveIn(unsigned PReg,
333                                    const TargetRegisterClass *RC) {
334  assert(RC->contains(PReg) && "Not the correct regclass!");
335  unsigned VReg = getRegInfo().createVirtualRegister(RC);
336  getRegInfo().addLiveIn(PReg, VReg);
337  return VReg;
338}
339
340/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
341/// source file, line, and column. If none currently exists, create a new
342/// DebugLocTuple, and insert it into the DebugIdMap.
343unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
344                                                unsigned Line, unsigned Col) {
345  DebugLocTuple Tuple(CompileUnit, Line, Col);
346  DenseMap<DebugLocTuple, unsigned>::iterator II
347    = DebugLocInfo.DebugIdMap.find(Tuple);
348  if (II != DebugLocInfo.DebugIdMap.end())
349    return II->second;
350  // Add a new tuple.
351  unsigned Id = DebugLocInfo.DebugLocations.size();
352  DebugLocInfo.DebugLocations.push_back(Tuple);
353  DebugLocInfo.DebugIdMap[Tuple] = Id;
354  return Id;
355}
356
357/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
358DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
359  unsigned Idx = DL.getIndex();
360  assert(Idx < DebugLocInfo.DebugLocations.size() &&
361         "Invalid index into debug locations!");
362  return DebugLocInfo.DebugLocations[Idx];
363}
364
365//===----------------------------------------------------------------------===//
366//  MachineFrameInfo implementation
367//===----------------------------------------------------------------------===//
368
369/// CreateFixedObject - Create a new object at a fixed location on the stack.
370/// All fixed objects should be created before other objects are created for
371/// efficiency. By default, fixed objects are immutable. This returns an
372/// index with a negative value.
373///
374int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
375                                        bool Immutable) {
376  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
377  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
378  return -++NumFixedObjects;
379}
380
381
382BitVector
383MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
384  assert(MBB && "MBB must be valid");
385  const MachineFunction *MF = MBB->getParent();
386  assert(MF && "MBB must be part of a MachineFunction");
387  const TargetMachine &TM = MF->getTarget();
388  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
389  BitVector BV(TRI->getNumRegs());
390
391  // Before CSI is calculated, no registers are considered pristine. They can be
392  // freely used and PEI will make sure they are saved.
393  if (!isCalleeSavedInfoValid())
394    return BV;
395
396  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
397    BV.set(*CSR);
398
399  // The entry MBB always has all CSRs pristine.
400  if (MBB == &MF->front())
401    return BV;
402
403  // On other MBBs the saved CSRs are not pristine.
404  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
405  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
406         E = CSI.end(); I != E; ++I)
407    BV.reset(I->getReg());
408
409  return BV;
410}
411
412
413void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
414  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
415  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
416
417  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
418    const StackObject &SO = Objects[i];
419    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
420    if (SO.Size == ~0ULL) {
421      OS << "dead\n";
422      continue;
423    }
424    if (SO.Size == 0)
425      OS << "variable sized";
426    else
427      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
428    OS << " alignment is " << SO.Alignment << " byte"
429       << (SO.Alignment != 1 ? "s," : ",");
430
431    if (i < NumFixedObjects)
432      OS << " fixed";
433    if (i < NumFixedObjects || SO.SPOffset != -1) {
434      int64_t Off = SO.SPOffset - ValOffset;
435      OS << " at location [SP";
436      if (Off > 0)
437        OS << "+" << Off;
438      else if (Off < 0)
439        OS << Off;
440      OS << "]";
441    }
442    OS << "\n";
443  }
444
445  if (HasVarSizedObjects)
446    OS << "  Stack frame contains variable sized objects\n";
447}
448
449void MachineFrameInfo::dump(const MachineFunction &MF) const {
450  print(MF, *cerr.stream());
451}
452
453//===----------------------------------------------------------------------===//
454//  MachineJumpTableInfo implementation
455//===----------------------------------------------------------------------===//
456
457/// getJumpTableIndex - Create a new jump table entry in the jump table info
458/// or return an existing one.
459///
460unsigned MachineJumpTableInfo::getJumpTableIndex(
461                               const std::vector<MachineBasicBlock*> &DestBBs) {
462  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
463  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
464    if (JumpTables[i].MBBs == DestBBs)
465      return i;
466
467  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
468  return JumpTables.size()-1;
469}
470
471/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
472/// the jump tables to branch to New instead.
473bool
474MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
475                                             MachineBasicBlock *New) {
476  assert(Old != New && "Not making a change?");
477  bool MadeChange = false;
478  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
479    MachineJumpTableEntry &JTE = JumpTables[i];
480    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
481      if (JTE.MBBs[j] == Old) {
482        JTE.MBBs[j] = New;
483        MadeChange = true;
484      }
485  }
486  return MadeChange;
487}
488
489void MachineJumpTableInfo::print(std::ostream &OS) const {
490  // FIXME: this is lame, maybe we could print out the MBB numbers or something
491  // like {1, 2, 4, 5, 3, 0}
492  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
493    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
494       << " entries\n";
495  }
496}
497
498void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
499
500
501//===----------------------------------------------------------------------===//
502//  MachineConstantPool implementation
503//===----------------------------------------------------------------------===//
504
505const Type *MachineConstantPoolEntry::getType() const {
506  if (isMachineConstantPoolEntry())
507    return Val.MachineCPVal->getType();
508  return Val.ConstVal->getType();
509}
510
511
512unsigned MachineConstantPoolEntry::getRelocationInfo() const {
513  if (isMachineConstantPoolEntry())
514    return Val.MachineCPVal->getRelocationInfo();
515  return Val.ConstVal->getRelocationInfo();
516}
517
518MachineConstantPool::~MachineConstantPool() {
519  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
520    if (Constants[i].isMachineConstantPoolEntry())
521      delete Constants[i].Val.MachineCPVal;
522}
523
524/// getConstantPoolIndex - Create a new entry in the constant pool or return
525/// an existing one.  User must specify the log2 of the minimum required
526/// alignment for the object.
527///
528unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
529                                                   unsigned Alignment) {
530  assert(Alignment && "Alignment must be specified!");
531  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
532
533  // Check to see if we already have this constant.
534  //
535  // FIXME, this could be made much more efficient for large constant pools.
536  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
537    if (Constants[i].Val.ConstVal == C &&
538        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
539      return i;
540
541  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
542  return Constants.size()-1;
543}
544
545unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
546                                                   unsigned Alignment) {
547  assert(Alignment && "Alignment must be specified!");
548  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
549
550  // Check to see if we already have this constant.
551  //
552  // FIXME, this could be made much more efficient for large constant pools.
553  int Idx = V->getExistingMachineCPValue(this, Alignment);
554  if (Idx != -1)
555    return (unsigned)Idx;
556
557  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
558  return Constants.size()-1;
559}
560
561void MachineConstantPool::print(raw_ostream &OS) const {
562  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
563    OS << "  <cp#" << i << "> is";
564    if (Constants[i].isMachineConstantPoolEntry())
565      Constants[i].Val.MachineCPVal->print(OS);
566    else
567      OS << *(Value*)Constants[i].Val.ConstVal;
568    OS << " , alignment=" << Constants[i].getAlignment();
569    OS << "\n";
570  }
571}
572
573void MachineConstantPool::dump() const { print(errs()); }
574