MachineFunction.cpp revision 3380d5c4aaafc3d78d32f583d685d64a67ae5224 
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
39bool MachineFunctionPass::runOnFunction(Function &F) {
40  // Do not codegen any 'available_externally' functions at all, they have
41  // definitions outside the translation unit.
42  if (F.hasAvailableExternallyLinkage())
43    return false;
44
45  return runOnMachineFunction(MachineFunction::get(&F));
46}
47
48namespace {
49  struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
50    static char ID;
51
52    std::ostream *OS;
53    const std::string Banner;
54
55    Printer (std::ostream *os, const std::string &banner)
56      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
57
58    const char *getPassName() const { return "MachineFunction Printer"; }
59
60    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
61      AU.setPreservesAll();
62    }
63
64    bool runOnMachineFunction(MachineFunction &MF) {
65      (*OS) << Banner;
66      MF.print (*OS);
67      return false;
68    }
69  };
70  char Printer::ID = 0;
71}
72
73/// Returns a newly-created MachineFunction Printer pass. The default output
74/// stream is std::cerr; the default banner is empty.
75///
76FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
77                                                     const std::string &Banner){
78  return new Printer(OS, Banner);
79}
80
81namespace {
82  struct VISIBILITY_HIDDEN Deleter : public MachineFunctionPass {
83    static char ID;
84    Deleter() : MachineFunctionPass(&ID) {}
85
86    const char *getPassName() const { return "Machine Code Deleter"; }
87
88    bool runOnMachineFunction(MachineFunction &MF) {
89      // Delete the annotation from the function now.
90      MachineFunction::destruct(MF.getFunction());
91      return true;
92    }
93  };
94  char Deleter::ID = 0;
95}
96
97/// MachineCodeDeletion Pass - This pass deletes all of the machine code for
98/// the current function, which should happen after the function has been
99/// emitted to a .s file or to memory.
100FunctionPass *llvm::createMachineCodeDeleter() {
101  return new Deleter();
102}
103
104
105
106//===---------------------------------------------------------------------===//
107// MachineFunction implementation
108//===---------------------------------------------------------------------===//
109
110void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
111  MBB->getParent()->DeleteMachineBasicBlock(MBB);
112}
113
114MachineFunction::MachineFunction(const Function *F,
115                                 const TargetMachine &TM)
116  : Annotation(AnnotationManager::getID("CodeGen::MachineCodeForFunction")),
117    Fn(F), Target(TM) {
118  if (TM.getRegisterInfo())
119    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
120                  MachineRegisterInfo(*TM.getRegisterInfo());
121  else
122    RegInfo = 0;
123  MFInfo = 0;
124  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
125                  MachineFrameInfo(*TM.getFrameInfo());
126  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
127                     MachineConstantPool(TM.getTargetData());
128  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
129
130  // Set up jump table.
131  const TargetData &TD = *TM.getTargetData();
132  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
133  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
134  unsigned TyAlignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
135                               : TD.getPointerABIAlignment();
136  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
137                      MachineJumpTableInfo(EntrySize, TyAlignment);
138}
139
140MachineFunction::~MachineFunction() {
141  BasicBlocks.clear();
142  InstructionRecycler.clear(Allocator);
143  BasicBlockRecycler.clear(Allocator);
144  if (RegInfo) {
145    RegInfo->~MachineRegisterInfo();
146    Allocator.Deallocate(RegInfo);
147  }
148  if (MFInfo) {
149    MFInfo->~MachineFunctionInfo();
150    Allocator.Deallocate(MFInfo);
151  }
152  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
153  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
154  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
155}
156
157
158/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
159/// recomputes them.  This guarantees that the MBB numbers are sequential,
160/// dense, and match the ordering of the blocks within the function.  If a
161/// specific MachineBasicBlock is specified, only that block and those after
162/// it are renumbered.
163void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
164  if (empty()) { MBBNumbering.clear(); return; }
165  MachineFunction::iterator MBBI, E = end();
166  if (MBB == 0)
167    MBBI = begin();
168  else
169    MBBI = MBB;
170
171  // Figure out the block number this should have.
172  unsigned BlockNo = 0;
173  if (MBBI != begin())
174    BlockNo = prior(MBBI)->getNumber()+1;
175
176  for (; MBBI != E; ++MBBI, ++BlockNo) {
177    if (MBBI->getNumber() != (int)BlockNo) {
178      // Remove use of the old number.
179      if (MBBI->getNumber() != -1) {
180        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
181               "MBB number mismatch!");
182        MBBNumbering[MBBI->getNumber()] = 0;
183      }
184
185      // If BlockNo is already taken, set that block's number to -1.
186      if (MBBNumbering[BlockNo])
187        MBBNumbering[BlockNo]->setNumber(-1);
188
189      MBBNumbering[BlockNo] = MBBI;
190      MBBI->setNumber(BlockNo);
191    }
192  }
193
194  // Okay, all the blocks are renumbered.  If we have compactified the block
195  // numbering, shrink MBBNumbering now.
196  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
197  MBBNumbering.resize(BlockNo);
198}
199
200/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
201/// of `new MachineInstr'.
202///
203MachineInstr *
204MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
205                                    DebugLoc DL, bool NoImp) {
206  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
207    MachineInstr(TID, DL, NoImp);
208}
209
210/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
211/// 'Orig' instruction, identical in all ways except the the instruction
212/// has no parent, prev, or next.
213///
214MachineInstr *
215MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
216  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
217             MachineInstr(*this, *Orig);
218}
219
220/// DeleteMachineInstr - Delete the given MachineInstr.
221///
222void
223MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
224  // Clear the instructions memoperands. This must be done manually because
225  // the instruction's parent pointer is now null, so it can't properly
226  // deallocate them on its own.
227  MI->clearMemOperands(*this);
228
229  MI->~MachineInstr();
230  InstructionRecycler.Deallocate(Allocator, MI);
231}
232
233/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
234/// instead of `new MachineBasicBlock'.
235///
236MachineBasicBlock *
237MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
238  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
239             MachineBasicBlock(*this, bb);
240}
241
242/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
243///
244void
245MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
246  assert(MBB->getParent() == this && "MBB parent mismatch!");
247  MBB->~MachineBasicBlock();
248  BasicBlockRecycler.Deallocate(Allocator, MBB);
249}
250
251void MachineFunction::dump() const {
252  print(*cerr.stream());
253}
254
255void MachineFunction::print(std::ostream &OS) const {
256  OS << "# Machine code for " << Fn->getName () << "():\n";
257
258  // Print Frame Information
259  FrameInfo->print(*this, OS);
260
261  // Print JumpTable Information
262  JumpTableInfo->print(OS);
263
264  // Print Constant Pool
265  {
266    raw_os_ostream OSS(OS);
267    ConstantPool->print(OSS);
268  }
269
270  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
271
272  if (RegInfo && !RegInfo->livein_empty()) {
273    OS << "Live Ins:";
274    for (MachineRegisterInfo::livein_iterator
275         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
276      if (TRI)
277        OS << " " << TRI->getName(I->first);
278      else
279        OS << " Reg #" << I->first;
280
281      if (I->second)
282        OS << " in VR#" << I->second << " ";
283    }
284    OS << "\n";
285  }
286  if (RegInfo && !RegInfo->liveout_empty()) {
287    OS << "Live Outs:";
288    for (MachineRegisterInfo::liveout_iterator
289         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
290      if (TRI)
291        OS << " " << TRI->getName(*I);
292      else
293        OS << " Reg #" << *I;
294    OS << "\n";
295  }
296
297  for (const_iterator BB = begin(); BB != end(); ++BB)
298    BB->print(OS);
299
300  OS << "\n# End machine code for " << Fn->getName () << "().\n\n";
301}
302
303namespace llvm {
304  template<>
305  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
306    static std::string getGraphName(const MachineFunction *F) {
307      return "CFG for '" + F->getFunction()->getName() + "' function";
308    }
309
310    static std::string getNodeLabel(const MachineBasicBlock *Node,
311                                    const MachineFunction *Graph,
312                                    bool ShortNames) {
313      if (ShortNames && Node->getBasicBlock() &&
314          !Node->getBasicBlock()->getName().empty())
315        return Node->getBasicBlock()->getName() + ":";
316
317      std::ostringstream Out;
318      if (ShortNames) {
319        Out << Node->getNumber() << ':';
320        return Out.str();
321      }
322
323      Node->print(Out);
324
325      std::string OutStr = Out.str();
326      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
327
328      // Process string output to make it nicer...
329      for (unsigned i = 0; i != OutStr.length(); ++i)
330        if (OutStr[i] == '\n') {                            // Left justify
331          OutStr[i] = '\\';
332          OutStr.insert(OutStr.begin()+i+1, 'l');
333        }
334      return OutStr;
335    }
336  };
337}
338
339void MachineFunction::viewCFG() const
340{
341#ifndef NDEBUG
342  ViewGraph(this, "mf" + getFunction()->getName());
343#else
344  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
345       << "systems with Graphviz or gv!\n";
346#endif // NDEBUG
347}
348
349void MachineFunction::viewCFGOnly() const
350{
351#ifndef NDEBUG
352  ViewGraph(this, "mf" + getFunction()->getName(), true);
353#else
354  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
355       << "systems with Graphviz or gv!\n";
356#endif // NDEBUG
357}
358
359// The next two methods are used to construct and to retrieve
360// the MachineCodeForFunction object for the given function.
361// construct() -- Allocates and initializes for a given function and target
362// get()       -- Returns a handle to the object.
363//                This should not be called before "construct()"
364//                for a given Function.
365//
366MachineFunction&
367MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
368{
369  AnnotationID MF_AID =
370                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
371  assert(Fn->getAnnotation(MF_AID) == 0 &&
372         "Object already exists for this function!");
373  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
374  Fn->addAnnotation(mcInfo);
375  return *mcInfo;
376}
377
378void MachineFunction::destruct(const Function *Fn) {
379  AnnotationID MF_AID =
380                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
381  bool Deleted = Fn->deleteAnnotation(MF_AID);
382  assert(Deleted && "Machine code did not exist for function!");
383  Deleted = Deleted; // silence warning when no assertions.
384}
385
386MachineFunction& MachineFunction::get(const Function *F)
387{
388  AnnotationID MF_AID =
389                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
390  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
391  assert(mc && "Call construct() method first to allocate the object");
392  return *mc;
393}
394
395/// addLiveIn - Add the specified physical register as a live-in value and
396/// create a corresponding virtual register for it.
397unsigned MachineFunction::addLiveIn(unsigned PReg,
398                                    const TargetRegisterClass *RC) {
399  assert(RC->contains(PReg) && "Not the correct regclass!");
400  unsigned VReg = getRegInfo().createVirtualRegister(RC);
401  getRegInfo().addLiveIn(PReg, VReg);
402  return VReg;
403}
404
405/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
406/// source file, line, and column. If none currently exists, create a new
407/// DebugLocTuple, and insert it into the DebugIdMap.
408unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
409                                                unsigned Line, unsigned Col) {
410  DebugLocTuple Tuple(CompileUnit, Line, Col);
411  DenseMap<DebugLocTuple, unsigned>::iterator II
412    = DebugLocInfo.DebugIdMap.find(Tuple);
413  if (II != DebugLocInfo.DebugIdMap.end())
414    return II->second;
415  // Add a new tuple.
416  unsigned Id = DebugLocInfo.DebugLocations.size();
417  DebugLocInfo.DebugLocations.push_back(Tuple);
418  DebugLocInfo.DebugIdMap[Tuple] = Id;
419  return Id;
420}
421
422/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
423DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
424  unsigned Idx = DL.getIndex();
425  assert(Idx < DebugLocInfo.DebugLocations.size() &&
426         "Invalid index into debug locations!");
427  return DebugLocInfo.DebugLocations[Idx];
428}
429
430//===----------------------------------------------------------------------===//
431//  MachineFrameInfo implementation
432//===----------------------------------------------------------------------===//
433
434/// CreateFixedObject - Create a new object at a fixed location on the stack.
435/// All fixed objects should be created before other objects are created for
436/// efficiency. By default, fixed objects are immutable. This returns an
437/// index with a negative value.
438///
439int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
440                                        bool Immutable) {
441  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
442  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
443  return -++NumFixedObjects;
444}
445
446
447void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
448  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
449  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
450
451  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
452    const StackObject &SO = Objects[i];
453    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
454    if (SO.Size == ~0ULL) {
455      OS << "dead\n";
456      continue;
457    }
458    if (SO.Size == 0)
459      OS << "variable sized";
460    else
461      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
462    OS << " alignment is " << SO.Alignment << " byte"
463       << (SO.Alignment != 1 ? "s," : ",");
464
465    if (i < NumFixedObjects)
466      OS << " fixed";
467    if (i < NumFixedObjects || SO.SPOffset != -1) {
468      int64_t Off = SO.SPOffset - ValOffset;
469      OS << " at location [SP";
470      if (Off > 0)
471        OS << "+" << Off;
472      else if (Off < 0)
473        OS << Off;
474      OS << "]";
475    }
476    OS << "\n";
477  }
478
479  if (HasVarSizedObjects)
480    OS << "  Stack frame contains variable sized objects\n";
481}
482
483void MachineFrameInfo::dump(const MachineFunction &MF) const {
484  print(MF, *cerr.stream());
485}
486
487
488//===----------------------------------------------------------------------===//
489//  MachineJumpTableInfo implementation
490//===----------------------------------------------------------------------===//
491
492/// getJumpTableIndex - Create a new jump table entry in the jump table info
493/// or return an existing one.
494///
495unsigned MachineJumpTableInfo::getJumpTableIndex(
496                               const std::vector<MachineBasicBlock*> &DestBBs) {
497  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
498  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
499    if (JumpTables[i].MBBs == DestBBs)
500      return i;
501
502  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
503  return JumpTables.size()-1;
504}
505
506/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
507/// the jump tables to branch to New instead.
508bool
509MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
510                                             MachineBasicBlock *New) {
511  assert(Old != New && "Not making a change?");
512  bool MadeChange = false;
513  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
514    MachineJumpTableEntry &JTE = JumpTables[i];
515    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
516      if (JTE.MBBs[j] == Old) {
517        JTE.MBBs[j] = New;
518        MadeChange = true;
519      }
520  }
521  return MadeChange;
522}
523
524void MachineJumpTableInfo::print(std::ostream &OS) const {
525  // FIXME: this is lame, maybe we could print out the MBB numbers or something
526  // like {1, 2, 4, 5, 3, 0}
527  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
528    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
529       << " entries\n";
530  }
531}
532
533void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
534
535
536//===----------------------------------------------------------------------===//
537//  MachineConstantPool implementation
538//===----------------------------------------------------------------------===//
539
540const Type *MachineConstantPoolEntry::getType() const {
541  if (isMachineConstantPoolEntry())
542      return Val.MachineCPVal->getType();
543  return Val.ConstVal->getType();
544}
545
546MachineConstantPool::~MachineConstantPool() {
547  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
548    if (Constants[i].isMachineConstantPoolEntry())
549      delete Constants[i].Val.MachineCPVal;
550}
551
552/// getConstantPoolIndex - Create a new entry in the constant pool or return
553/// an existing one.  User must specify the log2 of the minimum required
554/// alignment for the object.
555///
556unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
557                                                   unsigned Alignment) {
558  assert(Alignment && "Alignment must be specified!");
559  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
560
561  // Check to see if we already have this constant.
562  //
563  // FIXME, this could be made much more efficient for large constant pools.
564  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
565    if (Constants[i].Val.ConstVal == C &&
566        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
567      return i;
568
569  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
570  return Constants.size()-1;
571}
572
573unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
574                                                   unsigned Alignment) {
575  assert(Alignment && "Alignment must be specified!");
576  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
577
578  // Check to see if we already have this constant.
579  //
580  // FIXME, this could be made much more efficient for large constant pools.
581  int Idx = V->getExistingMachineCPValue(this, Alignment);
582  if (Idx != -1)
583    return (unsigned)Idx;
584
585  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
586  return Constants.size()-1;
587}
588
589void MachineConstantPool::print(raw_ostream &OS) const {
590  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
591    OS << "  <cp#" << i << "> is";
592    if (Constants[i].isMachineConstantPoolEntry())
593      Constants[i].Val.MachineCPVal->print(OS);
594    else
595      OS << *(Value*)Constants[i].Val.ConstVal;
596    OS << " , alignment=" << Constants[i].getAlignment();
597    OS << "\n";
598  }
599}
600
601void MachineConstantPool::dump() const { print(errs()); }
602