MachineFunction.cpp revision b5257664795d49ada0d4669fe8ed1cd49c04fbf3 
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 ? TD.getABITypeAlignment(Type::Int32Ty)
101                               : TD.getPointerABIAlignment();
102  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
103                      MachineJumpTableInfo(EntrySize, TyAlignment);
104}
105
106MachineFunction::~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.
129void 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///
169MachineInstr *
170MachineFunction::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///
180MachineInstr *
181MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
182  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
183             MachineInstr(*this, *Orig);
184}
185
186/// DeleteMachineInstr - Delete the given MachineInstr.
187///
188void
189MachineFunction::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///
202MachineBasicBlock *
203MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
204  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
205             MachineBasicBlock(*this, bb);
206}
207
208/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
209///
210void
211MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
212  assert(MBB->getParent() == this && "MBB parent mismatch!");
213  MBB->~MachineBasicBlock();
214  BasicBlockRecycler.Deallocate(Allocator, MBB);
215}
216
217void MachineFunction::dump() const {
218  print(*cerr.stream());
219}
220
221void MachineFunction::print(std::ostream &OS,
222                            const PrefixPrinter &prefix) const {
223  OS << "# Machine code for " << Fn->getNameStr () << "():\n";
224
225  // Print Frame Information
226  FrameInfo->print(*this, OS);
227
228  // Print JumpTable Information
229  JumpTableInfo->print(OS);
230
231  // Print Constant Pool
232  {
233    raw_os_ostream OSS(OS);
234    ConstantPool->print(OSS);
235  }
236
237  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
238
239  if (RegInfo && !RegInfo->livein_empty()) {
240    OS << "Live Ins:";
241    for (MachineRegisterInfo::livein_iterator
242         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
243      if (TRI)
244        OS << " " << TRI->getName(I->first);
245      else
246        OS << " Reg #" << I->first;
247
248      if (I->second)
249        OS << " in VR#" << I->second << " ";
250    }
251    OS << "\n";
252  }
253  if (RegInfo && !RegInfo->liveout_empty()) {
254    OS << "Live Outs:";
255    for (MachineRegisterInfo::liveout_iterator
256         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
257      if (TRI)
258        OS << " " << TRI->getName(*I);
259      else
260        OS << " Reg #" << *I;
261    OS << "\n";
262  }
263
264  for (const_iterator BB = begin(); BB != end(); ++BB) {
265    prefix(OS, *BB);
266    BB->print(OS, prefix);
267  }
268
269  OS << "\n# End machine code for " << Fn->getNameStr () << "().\n\n";
270}
271
272namespace llvm {
273  template<>
274  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
275    static std::string getGraphName(const MachineFunction *F) {
276      return "CFG for '" + F->getFunction()->getNameStr() + "' function";
277    }
278
279    static std::string getNodeLabel(const MachineBasicBlock *Node,
280                                    const MachineFunction *Graph,
281                                    bool ShortNames) {
282      if (ShortNames && Node->getBasicBlock() &&
283          !Node->getBasicBlock()->getName().empty())
284        return Node->getBasicBlock()->getNameStr() + ":";
285
286      std::ostringstream Out;
287      if (ShortNames) {
288        Out << Node->getNumber() << ':';
289        return Out.str();
290      }
291
292      Node->print(Out);
293
294      std::string OutStr = Out.str();
295      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
296
297      // Process string output to make it nicer...
298      for (unsigned i = 0; i != OutStr.length(); ++i)
299        if (OutStr[i] == '\n') {                            // Left justify
300          OutStr[i] = '\\';
301          OutStr.insert(OutStr.begin()+i+1, 'l');
302        }
303      return OutStr;
304    }
305  };
306}
307
308void MachineFunction::viewCFG() const
309{
310#ifndef NDEBUG
311  ViewGraph(this, "mf" + getFunction()->getNameStr());
312#else
313  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
314       << "systems with Graphviz or gv!\n";
315#endif // NDEBUG
316}
317
318void MachineFunction::viewCFGOnly() const
319{
320#ifndef NDEBUG
321  ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
322#else
323  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
324       << "systems with Graphviz or gv!\n";
325#endif // NDEBUG
326}
327
328/// addLiveIn - Add the specified physical register as a live-in value and
329/// create a corresponding virtual register for it.
330unsigned MachineFunction::addLiveIn(unsigned PReg,
331                                    const TargetRegisterClass *RC) {
332  assert(RC->contains(PReg) && "Not the correct regclass!");
333  unsigned VReg = getRegInfo().createVirtualRegister(RC);
334  getRegInfo().addLiveIn(PReg, VReg);
335  return VReg;
336}
337
338/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
339/// source file, line, and column. If none currently exists, create a new
340/// DebugLocTuple, and insert it into the DebugIdMap.
341unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
342                                                unsigned Line, unsigned Col) {
343  DebugLocTuple Tuple(CompileUnit, Line, Col);
344  DenseMap<DebugLocTuple, unsigned>::iterator II
345    = DebugLocInfo.DebugIdMap.find(Tuple);
346  if (II != DebugLocInfo.DebugIdMap.end())
347    return II->second;
348  // Add a new tuple.
349  unsigned Id = DebugLocInfo.DebugLocations.size();
350  DebugLocInfo.DebugLocations.push_back(Tuple);
351  DebugLocInfo.DebugIdMap[Tuple] = Id;
352  return Id;
353}
354
355/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
356DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
357  unsigned Idx = DL.getIndex();
358  assert(Idx < DebugLocInfo.DebugLocations.size() &&
359         "Invalid index into debug locations!");
360  return DebugLocInfo.DebugLocations[Idx];
361}
362
363//===----------------------------------------------------------------------===//
364//  MachineFrameInfo implementation
365//===----------------------------------------------------------------------===//
366
367/// CreateFixedObject - Create a new object at a fixed location on the stack.
368/// All fixed objects should be created before other objects are created for
369/// efficiency. By default, fixed objects are immutable. This returns an
370/// index with a negative value.
371///
372int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
373                                        bool Immutable) {
374  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
375  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
376  return -++NumFixedObjects;
377}
378
379
380void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
381  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
382  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
383
384  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
385    const StackObject &SO = Objects[i];
386    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
387    if (SO.Size == ~0ULL) {
388      OS << "dead\n";
389      continue;
390    }
391    if (SO.Size == 0)
392      OS << "variable sized";
393    else
394      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
395    OS << " alignment is " << SO.Alignment << " byte"
396       << (SO.Alignment != 1 ? "s," : ",");
397
398    if (i < NumFixedObjects)
399      OS << " fixed";
400    if (i < NumFixedObjects || SO.SPOffset != -1) {
401      int64_t Off = SO.SPOffset - ValOffset;
402      OS << " at location [SP";
403      if (Off > 0)
404        OS << "+" << Off;
405      else if (Off < 0)
406        OS << Off;
407      OS << "]";
408    }
409    OS << "\n";
410  }
411
412  if (HasVarSizedObjects)
413    OS << "  Stack frame contains variable sized objects\n";
414}
415
416void MachineFrameInfo::dump(const MachineFunction &MF) const {
417  print(MF, *cerr.stream());
418}
419
420
421//===----------------------------------------------------------------------===//
422//  MachineJumpTableInfo implementation
423//===----------------------------------------------------------------------===//
424
425/// getJumpTableIndex - Create a new jump table entry in the jump table info
426/// or return an existing one.
427///
428unsigned MachineJumpTableInfo::getJumpTableIndex(
429                               const std::vector<MachineBasicBlock*> &DestBBs) {
430  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
431  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
432    if (JumpTables[i].MBBs == DestBBs)
433      return i;
434
435  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
436  return JumpTables.size()-1;
437}
438
439/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
440/// the jump tables to branch to New instead.
441bool
442MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
443                                             MachineBasicBlock *New) {
444  assert(Old != New && "Not making a change?");
445  bool MadeChange = false;
446  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
447    MachineJumpTableEntry &JTE = JumpTables[i];
448    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
449      if (JTE.MBBs[j] == Old) {
450        JTE.MBBs[j] = New;
451        MadeChange = true;
452      }
453  }
454  return MadeChange;
455}
456
457void MachineJumpTableInfo::print(std::ostream &OS) const {
458  // FIXME: this is lame, maybe we could print out the MBB numbers or something
459  // like {1, 2, 4, 5, 3, 0}
460  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
461    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
462       << " entries\n";
463  }
464}
465
466void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
467
468
469//===----------------------------------------------------------------------===//
470//  MachineConstantPool implementation
471//===----------------------------------------------------------------------===//
472
473const Type *MachineConstantPoolEntry::getType() const {
474  if (isMachineConstantPoolEntry())
475    return Val.MachineCPVal->getType();
476  return Val.ConstVal->getType();
477}
478
479
480unsigned MachineConstantPoolEntry::getRelocationInfo() const {
481  if (isMachineConstantPoolEntry())
482    return Val.MachineCPVal->getRelocationInfo();
483  return Val.ConstVal->getRelocationInfo();
484}
485
486MachineConstantPool::~MachineConstantPool() {
487  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
488    if (Constants[i].isMachineConstantPoolEntry())
489      delete Constants[i].Val.MachineCPVal;
490}
491
492/// getConstantPoolIndex - Create a new entry in the constant pool or return
493/// an existing one.  User must specify the log2 of the minimum required
494/// alignment for the object.
495///
496unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
497                                                   unsigned Alignment) {
498  assert(Alignment && "Alignment must be specified!");
499  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
500
501  // Check to see if we already have this constant.
502  //
503  // FIXME, this could be made much more efficient for large constant pools.
504  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
505    if (Constants[i].Val.ConstVal == C &&
506        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
507      return i;
508
509  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
510  return Constants.size()-1;
511}
512
513unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
514                                                   unsigned Alignment) {
515  assert(Alignment && "Alignment must be specified!");
516  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
517
518  // Check to see if we already have this constant.
519  //
520  // FIXME, this could be made much more efficient for large constant pools.
521  int Idx = V->getExistingMachineCPValue(this, Alignment);
522  if (Idx != -1)
523    return (unsigned)Idx;
524
525  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
526  return Constants.size()-1;
527}
528
529void MachineConstantPool::print(raw_ostream &OS) const {
530  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
531    OS << "  <cp#" << i << "> is";
532    if (Constants[i].isMachineConstantPoolEntry())
533      Constants[i].Val.MachineCPVal->print(OS);
534    else
535      OS << *(Value*)Constants[i].Val.ConstVal;
536    OS << " , alignment=" << Constants[i].getAlignment();
537    OS << "\n";
538  }
539}
540
541void MachineConstantPool::dump() const { print(errs()); }
542