MachineFunction.cpp revision 29626642271ae810dd526de8afa151484452abe0 
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  // Set up jump table.
97  const TargetData &TD = *TM.getTargetData();
98  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
99  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
100  unsigned TyAlignment = IsPic ?
101                       TD.getABITypeAlignment(Type::getInt32Ty(F->getContext()))
102                               : TD.getPointerABIAlignment();
103  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
104                      MachineJumpTableInfo(EntrySize, TyAlignment);
105}
106
107MachineFunction::~MachineFunction() {
108  BasicBlocks.clear();
109  InstructionRecycler.clear(Allocator);
110  BasicBlockRecycler.clear(Allocator);
111  if (RegInfo) {
112    RegInfo->~MachineRegisterInfo();
113    Allocator.Deallocate(RegInfo);
114  }
115  if (MFInfo) {
116    MFInfo->~MachineFunctionInfo();
117    Allocator.Deallocate(MFInfo);
118  }
119  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
120  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
121  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
122}
123
124
125/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
126/// recomputes them.  This guarantees that the MBB numbers are sequential,
127/// dense, and match the ordering of the blocks within the function.  If a
128/// specific MachineBasicBlock is specified, only that block and those after
129/// it are renumbered.
130void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
131  if (empty()) { MBBNumbering.clear(); return; }
132  MachineFunction::iterator MBBI, E = end();
133  if (MBB == 0)
134    MBBI = begin();
135  else
136    MBBI = MBB;
137
138  // Figure out the block number this should have.
139  unsigned BlockNo = 0;
140  if (MBBI != begin())
141    BlockNo = prior(MBBI)->getNumber()+1;
142
143  for (; MBBI != E; ++MBBI, ++BlockNo) {
144    if (MBBI->getNumber() != (int)BlockNo) {
145      // Remove use of the old number.
146      if (MBBI->getNumber() != -1) {
147        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
148               "MBB number mismatch!");
149        MBBNumbering[MBBI->getNumber()] = 0;
150      }
151
152      // If BlockNo is already taken, set that block's number to -1.
153      if (MBBNumbering[BlockNo])
154        MBBNumbering[BlockNo]->setNumber(-1);
155
156      MBBNumbering[BlockNo] = MBBI;
157      MBBI->setNumber(BlockNo);
158    }
159  }
160
161  // Okay, all the blocks are renumbered.  If we have compactified the block
162  // numbering, shrink MBBNumbering now.
163  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
164  MBBNumbering.resize(BlockNo);
165}
166
167/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
168/// of `new MachineInstr'.
169///
170MachineInstr *
171MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
172                                    DebugLoc DL, bool NoImp) {
173  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
174    MachineInstr(TID, DL, NoImp);
175}
176
177/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
178/// 'Orig' instruction, identical in all ways except the the instruction
179/// has no parent, prev, or next.
180///
181MachineInstr *
182MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
183  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
184             MachineInstr(*this, *Orig);
185}
186
187/// DeleteMachineInstr - Delete the given MachineInstr.
188///
189void
190MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
191  // Clear the instructions memoperands. This must be done manually because
192  // the instruction's parent pointer is now null, so it can't properly
193  // deallocate them on its own.
194  MI->clearMemOperands(*this);
195
196  MI->~MachineInstr();
197  InstructionRecycler.Deallocate(Allocator, MI);
198}
199
200/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
201/// instead of `new MachineBasicBlock'.
202///
203MachineBasicBlock *
204MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
205  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
206             MachineBasicBlock(*this, bb);
207}
208
209/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
210///
211void
212MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
213  assert(MBB->getParent() == this && "MBB parent mismatch!");
214  MBB->~MachineBasicBlock();
215  BasicBlockRecycler.Deallocate(Allocator, MBB);
216}
217
218void MachineFunction::dump() const {
219  print(*cerr.stream());
220}
221
222void MachineFunction::print(std::ostream &OS,
223                            const PrefixPrinter &prefix) const {
224  OS << "# Machine code for " << Fn->getNameStr () << "():\n";
225
226  // Print Frame Information
227  FrameInfo->print(*this, OS);
228
229  // Print JumpTable Information
230  JumpTableInfo->print(OS);
231
232  // Print Constant Pool
233  {
234    raw_os_ostream OSS(OS);
235    ConstantPool->print(OSS);
236  }
237
238  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
239
240  if (RegInfo && !RegInfo->livein_empty()) {
241    OS << "Live Ins:";
242    for (MachineRegisterInfo::livein_iterator
243         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
244      if (TRI)
245        OS << " " << TRI->getName(I->first);
246      else
247        OS << " Reg #" << I->first;
248
249      if (I->second)
250        OS << " in VR#" << I->second << " ";
251    }
252    OS << "\n";
253  }
254  if (RegInfo && !RegInfo->liveout_empty()) {
255    OS << "Live Outs:";
256    for (MachineRegisterInfo::liveout_iterator
257         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
258      if (TRI)
259        OS << " " << TRI->getName(*I);
260      else
261        OS << " Reg #" << *I;
262    OS << "\n";
263  }
264
265  for (const_iterator BB = begin(); BB != end(); ++BB) {
266    prefix(OS, *BB);
267    BB->print(OS, prefix);
268  }
269
270  OS << "\n# End machine code for " << Fn->getNameStr () << "().\n\n";
271}
272
273namespace llvm {
274  template<>
275  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
276    static std::string getGraphName(const MachineFunction *F) {
277      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
278    }
279
280    static std::string getNodeLabel(const MachineBasicBlock *Node,
281                                    const MachineFunction *Graph,
282                                    bool ShortNames) {
283      if (ShortNames && Node->getBasicBlock() &&
284          !Node->getBasicBlock()->getName().empty())
285        return Node->getBasicBlock()->getNameStr() + ":";
286
287      std::ostringstream Out;
288      if (ShortNames) {
289        Out << Node->getNumber() << ':';
290        return Out.str();
291      }
292
293      Node->print(Out);
294
295      std::string OutStr = Out.str();
296      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
297
298      // Process string output to make it nicer...
299      for (unsigned i = 0; i != OutStr.length(); ++i)
300        if (OutStr[i] == '\n') {                            // Left justify
301          OutStr[i] = '\\';
302          OutStr.insert(OutStr.begin()+i+1, 'l');
303        }
304      return OutStr;
305    }
306  };
307}
308
309void MachineFunction::viewCFG() const
310{
311#ifndef NDEBUG
312  ViewGraph(this, "mf" + getFunction()->getNameStr());
313#else
314  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
315       << "systems with Graphviz or gv!\n";
316#endif // NDEBUG
317}
318
319void MachineFunction::viewCFGOnly() const
320{
321#ifndef NDEBUG
322  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
323#else
324  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
325       << "systems with Graphviz or gv!\n";
326#endif // NDEBUG
327}
328
329/// addLiveIn - Add the specified physical register as a live-in value and
330/// create a corresponding virtual register for it.
331unsigned MachineFunction::addLiveIn(unsigned PReg,
332                                    const TargetRegisterClass *RC) {
333  assert(RC->contains(PReg) && "Not the correct regclass!");
334  unsigned VReg = getRegInfo().createVirtualRegister(RC);
335  getRegInfo().addLiveIn(PReg, VReg);
336  return VReg;
337}
338
339/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
340/// source file, line, and column. If none currently exists, create a new
341/// DebugLocTuple, and insert it into the DebugIdMap.
342unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
343                                                unsigned Line, unsigned Col) {
344  DebugLocTuple Tuple(CompileUnit, Line, Col);
345  DenseMap<DebugLocTuple, unsigned>::iterator II
346    = DebugLocInfo.DebugIdMap.find(Tuple);
347  if (II != DebugLocInfo.DebugIdMap.end())
348    return II->second;
349  // Add a new tuple.
350  unsigned Id = DebugLocInfo.DebugLocations.size();
351  DebugLocInfo.DebugLocations.push_back(Tuple);
352  DebugLocInfo.DebugIdMap[Tuple] = Id;
353  return Id;
354}
355
356/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
357DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
358  unsigned Idx = DL.getIndex();
359  assert(Idx < DebugLocInfo.DebugLocations.size() &&
360         "Invalid index into debug locations!");
361  return DebugLocInfo.DebugLocations[Idx];
362}
363
364//===----------------------------------------------------------------------===//
365//  MachineFrameInfo implementation
366//===----------------------------------------------------------------------===//
367
368/// CreateFixedObject - Create a new object at a fixed location on the stack.
369/// All fixed objects should be created before other objects are created for
370/// efficiency. By default, fixed objects are immutable. This returns an
371/// index with a negative value.
372///
373int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
374                                        bool Immutable) {
375  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
376  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
377  return -++NumFixedObjects;
378}
379
380
381BitVector
382MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
383  assert(MBB && "MBB must be valid");
384  const MachineFunction *MF = MBB->getParent();
385  assert(MF && "MBB must be part of a MachineFunction");
386  const TargetMachine &TM = MF->getTarget();
387  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
388  BitVector BV(TRI->getNumRegs());
389
390  // Before CSI is calculated, no registers are considered pristine. They can be
391  // freely used and PEI will make sure they are saved.
392  if (!isCalleeSavedInfoValid())
393    return BV;
394
395  for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
396    BV.set(*CSR);
397
398  // The entry MBB always has all CSRs pristine.
399  if (MBB == &MF->front())
400    return BV;
401
402  // On other MBBs the saved CSRs are not pristine.
403  const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
404  for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
405         E = CSI.end(); I != E; ++I)
406    BV.reset(I->getReg());
407
408  return BV;
409}
410
411
412void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
413  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
414  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
415
416  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
417    const StackObject &SO = Objects[i];
418    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
419    if (SO.Size == ~0ULL) {
420      OS << "dead\n";
421      continue;
422    }
423    if (SO.Size == 0)
424      OS << "variable sized";
425    else
426      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
427    OS << " alignment is " << SO.Alignment << " byte"
428       << (SO.Alignment != 1 ? "s," : ",");
429
430    if (i < NumFixedObjects)
431      OS << " fixed";
432    if (i < NumFixedObjects || SO.SPOffset != -1) {
433      int64_t Off = SO.SPOffset - ValOffset;
434      OS << " at location [SP";
435      if (Off > 0)
436        OS << "+" << Off;
437      else if (Off < 0)
438        OS << Off;
439      OS << "]";
440    }
441    OS << "\n";
442  }
443
444  if (HasVarSizedObjects)
445    OS << "  Stack frame contains variable sized objects\n";
446}
447
448void MachineFrameInfo::dump(const MachineFunction &MF) const {
449  print(MF, *cerr.stream());
450}
451
452//===----------------------------------------------------------------------===//
453//  MachineJumpTableInfo implementation
454//===----------------------------------------------------------------------===//
455
456/// getJumpTableIndex - Create a new jump table entry in the jump table info
457/// or return an existing one.
458///
459unsigned MachineJumpTableInfo::getJumpTableIndex(
460                               const std::vector<MachineBasicBlock*> &DestBBs) {
461  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
462  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
463    if (JumpTables[i].MBBs == DestBBs)
464      return i;
465
466  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
467  return JumpTables.size()-1;
468}
469
470/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
471/// the jump tables to branch to New instead.
472bool
473MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
474                                             MachineBasicBlock *New) {
475  assert(Old != New && "Not making a change?");
476  bool MadeChange = false;
477  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
478    MachineJumpTableEntry &JTE = JumpTables[i];
479    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
480      if (JTE.MBBs[j] == Old) {
481        JTE.MBBs[j] = New;
482        MadeChange = true;
483      }
484  }
485  return MadeChange;
486}
487
488void MachineJumpTableInfo::print(std::ostream &OS) const {
489  // FIXME: this is lame, maybe we could print out the MBB numbers or something
490  // like {1, 2, 4, 5, 3, 0}
491  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
492    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
493       << " entries\n";
494  }
495}
496
497void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
498
499
500//===----------------------------------------------------------------------===//
501//  MachineConstantPool implementation
502//===----------------------------------------------------------------------===//
503
504const Type *MachineConstantPoolEntry::getType() const {
505  if (isMachineConstantPoolEntry())
506    return Val.MachineCPVal->getType();
507  return Val.ConstVal->getType();
508}
509
510
511unsigned MachineConstantPoolEntry::getRelocationInfo() const {
512  if (isMachineConstantPoolEntry())
513    return Val.MachineCPVal->getRelocationInfo();
514  return Val.ConstVal->getRelocationInfo();
515}
516
517MachineConstantPool::~MachineConstantPool() {
518  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
519    if (Constants[i].isMachineConstantPoolEntry())
520      delete Constants[i].Val.MachineCPVal;
521}
522
523/// getConstantPoolIndex - Create a new entry in the constant pool or return
524/// an existing one.  User must specify the log2 of the minimum required
525/// alignment for the object.
526///
527unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
528                                                   unsigned Alignment) {
529  assert(Alignment && "Alignment must be specified!");
530  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
531
532  // Check to see if we already have this constant.
533  //
534  // FIXME, this could be made much more efficient for large constant pools.
535  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
536    if (Constants[i].Val.ConstVal == C &&
537        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
538      return i;
539
540  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
541  return Constants.size()-1;
542}
543
544unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
545                                                   unsigned Alignment) {
546  assert(Alignment && "Alignment must be specified!");
547  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
548
549  // Check to see if we already have this constant.
550  //
551  // FIXME, this could be made much more efficient for large constant pools.
552  int Idx = V->getExistingMachineCPValue(this, Alignment);
553  if (Idx != -1)
554    return (unsigned)Idx;
555
556  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
557  return Constants.size()-1;
558}
559
560void MachineConstantPool::print(raw_ostream &OS) const {
561  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
562    OS << "  <cp#" << i << "> is";
563    if (Constants[i].isMachineConstantPoolEntry())
564      Constants[i].Val.MachineCPVal->print(OS);
565    else
566      OS << *(Value*)Constants[i].Val.ConstVal;
567    OS << " , alignment=" << Constants[i].getAlignment();
568    OS << "\n";
569  }
570}
571
572void MachineConstantPool::dump() const { print(errs()); }
573