MachineFunction.cpp revision 0e0da734bbdfa1d3f55cd04db31d83b97e4556f7 
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/CodeGen/MachineConstantPool.h"
18#include "llvm/CodeGen/MachineFunctionPass.h"
19#include "llvm/CodeGen/MachineFrameInfo.h"
20#include "llvm/CodeGen/MachineInstr.h"
21#include "llvm/CodeGen/MachineJumpTableInfo.h"
22#include "llvm/CodeGen/MachineRegisterInfo.h"
23#include "llvm/CodeGen/Passes.h"
24#include "llvm/Target/TargetData.h"
25#include "llvm/Target/TargetMachine.h"
26#include "llvm/Target/TargetFrameInfo.h"
27#include "llvm/Function.h"
28#include "llvm/Instructions.h"
29#include "llvm/Support/Compiler.h"
30#include "llvm/Support/GraphWriter.h"
31#include "llvm/Support/raw_ostream.h"
32#include "llvm/ADT/STLExtras.h"
33#include "llvm/Config/config.h"
34#include <fstream>
35#include <sstream>
36using namespace llvm;
37
38static AnnotationID MF_AID(
39  AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
40
41bool MachineFunctionPass::runOnFunction(Function &F) {
42  // Do not codegen any 'available_externally' functions at all, they have
43  // definitions outside the translation unit.
44  if (F.hasAvailableExternallyLinkage())
45    return false;
46
47  return runOnMachineFunction(MachineFunction::get(&F));
48}
49
50namespace {
51  struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
52    static char ID;
53
54    std::ostream *OS;
55    const std::string Banner;
56
57    Printer (std::ostream *os, const std::string &banner)
58      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
59
60    const char *getPassName() const { return "MachineFunction Printer"; }
61
62    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
63      AU.setPreservesAll();
64    }
65
66    bool runOnMachineFunction(MachineFunction &MF) {
67      (*OS) << Banner;
68      MF.print (*OS);
69      return false;
70    }
71  };
72  char Printer::ID = 0;
73}
74
75/// Returns a newly-created MachineFunction Printer pass. The default output
76/// stream is std::cerr; the default banner is empty.
77///
78FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
79                                                     const std::string &Banner){
80  return new Printer(OS, Banner);
81}
82
83namespace {
84  struct VISIBILITY_HIDDEN Deleter : public MachineFunctionPass {
85    static char ID;
86    Deleter() : MachineFunctionPass(&ID) {}
87
88    const char *getPassName() const { return "Machine Code Deleter"; }
89
90    bool runOnMachineFunction(MachineFunction &MF) {
91      // Delete the annotation from the function now.
92      MachineFunction::destruct(MF.getFunction());
93      return true;
94    }
95  };
96  char Deleter::ID = 0;
97}
98
99/// MachineCodeDeletion Pass - This pass deletes all of the machine code for
100/// the current function, which should happen after the function has been
101/// emitted to a .s file or to memory.
102FunctionPass *llvm::createMachineCodeDeleter() {
103  return new Deleter();
104}
105
106
107
108//===---------------------------------------------------------------------===//
109// MachineFunction implementation
110//===---------------------------------------------------------------------===//
111
112void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
113  MBB->getParent()->DeleteMachineBasicBlock(MBB);
114}
115
116MachineFunction::MachineFunction(const Function *F,
117                                 const TargetMachine &TM)
118  : Annotation(MF_AID), Fn(F), Target(TM) {
119  if (TM.getRegisterInfo())
120    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
121                  MachineRegisterInfo(*TM.getRegisterInfo());
122  else
123    RegInfo = 0;
124  HasBuiltinSetjmp = false;
125  MFInfo = 0;
126  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
127                  MachineFrameInfo(*TM.getFrameInfo());
128  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
129                     MachineConstantPool(TM.getTargetData());
130
131  // Set up jump table.
132  const TargetData &TD = *TM.getTargetData();
133  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
134  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
135  unsigned Alignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
136                             : TD.getPointerABIAlignment();
137  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
138                      MachineJumpTableInfo(EntrySize, Alignment);
139}
140
141MachineFunction::~MachineFunction() {
142  BasicBlocks.clear();
143  InstructionRecycler.clear(Allocator);
144  BasicBlockRecycler.clear(Allocator);
145  if (RegInfo)
146    RegInfo->~MachineRegisterInfo();        Allocator.Deallocate(RegInfo);
147  if (MFInfo) {
148    MFInfo->~MachineFunctionInfo();       Allocator.Deallocate(MFInfo);
149  }
150  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
151  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
152  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
153}
154
155
156/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
157/// recomputes them.  This guarantees that the MBB numbers are sequential,
158/// dense, and match the ordering of the blocks within the function.  If a
159/// specific MachineBasicBlock is specified, only that block and those after
160/// it are renumbered.
161void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
162  if (empty()) { MBBNumbering.clear(); return; }
163  MachineFunction::iterator MBBI, E = end();
164  if (MBB == 0)
165    MBBI = begin();
166  else
167    MBBI = MBB;
168
169  // Figure out the block number this should have.
170  unsigned BlockNo = 0;
171  if (MBBI != begin())
172    BlockNo = prior(MBBI)->getNumber()+1;
173
174  for (; MBBI != E; ++MBBI, ++BlockNo) {
175    if (MBBI->getNumber() != (int)BlockNo) {
176      // Remove use of the old number.
177      if (MBBI->getNumber() != -1) {
178        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
179               "MBB number mismatch!");
180        MBBNumbering[MBBI->getNumber()] = 0;
181      }
182
183      // If BlockNo is already taken, set that block's number to -1.
184      if (MBBNumbering[BlockNo])
185        MBBNumbering[BlockNo]->setNumber(-1);
186
187      MBBNumbering[BlockNo] = MBBI;
188      MBBI->setNumber(BlockNo);
189    }
190  }
191
192  // Okay, all the blocks are renumbered.  If we have compactified the block
193  // numbering, shrink MBBNumbering now.
194  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
195  MBBNumbering.resize(BlockNo);
196}
197
198/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
199/// of `new MachineInstr'.
200///
201MachineInstr *
202MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
203                                    DebugLoc DL, bool NoImp) {
204  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
205    MachineInstr(TID, DL, NoImp);
206}
207
208/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
209/// 'Orig' instruction, identical in all ways except the the instruction
210/// has no parent, prev, or next.
211///
212MachineInstr *
213MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
214  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
215             MachineInstr(*this, *Orig);
216}
217
218/// DeleteMachineInstr - Delete the given MachineInstr.
219///
220void
221MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
222  // Clear the instructions memoperands. This must be done manually because
223  // the instruction's parent pointer is now null, so it can't properly
224  // deallocate them on its own.
225  MI->clearMemOperands(*this);
226
227  MI->~MachineInstr();
228  InstructionRecycler.Deallocate(Allocator, MI);
229}
230
231/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
232/// instead of `new MachineBasicBlock'.
233///
234MachineBasicBlock *
235MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
236  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
237             MachineBasicBlock(*this, bb);
238}
239
240/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
241///
242void
243MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
244  assert(MBB->getParent() == this && "MBB parent mismatch!");
245  MBB->~MachineBasicBlock();
246  BasicBlockRecycler.Deallocate(Allocator, MBB);
247}
248
249void MachineFunction::dump() const {
250  print(*cerr.stream());
251}
252
253void MachineFunction::print(std::ostream &OS) const {
254  OS << "# Machine code for " << Fn->getName () << "():\n";
255
256  // Print Frame Information
257  FrameInfo->print(*this, OS);
258
259  // Print JumpTable Information
260  JumpTableInfo->print(OS);
261
262  // Print Constant Pool
263  {
264    raw_os_ostream OSS(OS);
265    ConstantPool->print(OSS);
266  }
267
268  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
269
270  if (RegInfo && !RegInfo->livein_empty()) {
271    OS << "Live Ins:";
272    for (MachineRegisterInfo::livein_iterator
273         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
274      if (TRI)
275        OS << " " << TRI->getName(I->first);
276      else
277        OS << " Reg #" << I->first;
278
279      if (I->second)
280        OS << " in VR#" << I->second << " ";
281    }
282    OS << "\n";
283  }
284  if (RegInfo && !RegInfo->liveout_empty()) {
285    OS << "Live Outs:";
286    for (MachineRegisterInfo::liveout_iterator
287         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
288      if (TRI)
289        OS << " " << TRI->getName(*I);
290      else
291        OS << " Reg #" << *I;
292    OS << "\n";
293  }
294
295  for (const_iterator BB = begin(); BB != end(); ++BB)
296    BB->print(OS);
297
298  OS << "\n# End machine code for " << Fn->getName () << "().\n\n";
299}
300
301/// CFGOnly flag - This is used to control whether or not the CFG graph printer
302/// prints out the contents of basic blocks or not.  This is acceptable because
303/// this code is only really used for debugging purposes.
304///
305static bool CFGOnly = false;
306
307namespace llvm {
308  template<>
309  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
310    static std::string getGraphName(const MachineFunction *F) {
311      return "CFG for '" + F->getFunction()->getName() + "' function";
312    }
313
314    static std::string getNodeLabel(const MachineBasicBlock *Node,
315                                    const MachineFunction *Graph) {
316      if (CFGOnly && Node->getBasicBlock() &&
317          !Node->getBasicBlock()->getName().empty())
318        return Node->getBasicBlock()->getName() + ":";
319
320      std::ostringstream Out;
321      if (CFGOnly) {
322        Out << Node->getNumber() << ':';
323        return Out.str();
324      }
325
326      Node->print(Out);
327
328      std::string OutStr = Out.str();
329      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
330
331      // Process string output to make it nicer...
332      for (unsigned i = 0; i != OutStr.length(); ++i)
333        if (OutStr[i] == '\n') {                            // Left justify
334          OutStr[i] = '\\';
335          OutStr.insert(OutStr.begin()+i+1, 'l');
336        }
337      return OutStr;
338    }
339  };
340}
341
342void MachineFunction::viewCFG() const
343{
344#ifndef NDEBUG
345  ViewGraph(this, "mf" + getFunction()->getName());
346#else
347  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
348       << "systems with Graphviz or gv!\n";
349#endif // NDEBUG
350}
351
352void MachineFunction::viewCFGOnly() const
353{
354  CFGOnly = true;
355  viewCFG();
356  CFGOnly = false;
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  assert(Fn->getAnnotation(MF_AID) == 0 &&
370         "Object already exists for this function!");
371  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
372  Fn->addAnnotation(mcInfo);
373  return *mcInfo;
374}
375
376void MachineFunction::destruct(const Function *Fn) {
377  bool Deleted = Fn->deleteAnnotation(MF_AID);
378  assert(Deleted && "Machine code did not exist for function!");
379  Deleted = Deleted; // silence warning when no assertions.
380}
381
382MachineFunction& MachineFunction::get(const Function *F)
383{
384  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
385  assert(mc && "Call construct() method first to allocate the object");
386  return *mc;
387}
388
389/// addLiveIn - Add the specified physical register as a live-in value and
390/// create a corresponding virtual register for it.
391unsigned MachineFunction::addLiveIn(unsigned PReg,
392                                    const TargetRegisterClass *RC) {
393  assert(RC->contains(PReg) && "Not the correct regclass!");
394  unsigned VReg = getRegInfo().createVirtualRegister(RC);
395  getRegInfo().addLiveIn(PReg, VReg);
396  return VReg;
397}
398
399/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
400/// source file, line, and column. If none currently exists, create a new
401/// DebugLocTuple, and insert it into the DebugIdMap.
402unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
403                                                unsigned Line, unsigned Col) {
404  DebugLocTuple Tuple(CompileUnit, Line, Col);
405  DenseMap<DebugLocTuple, unsigned>::iterator II
406    = DebugLocInfo.DebugIdMap.find(Tuple);
407  if (II != DebugLocInfo.DebugIdMap.end())
408    return II->second;
409  // Add a new tuple.
410  unsigned Id = DebugLocInfo.DebugLocations.size();
411  DebugLocInfo.DebugLocations.push_back(Tuple);
412  DebugLocInfo.DebugIdMap[Tuple] = Id;
413  return Id;
414}
415
416/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
417DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
418  unsigned Idx = DL.getIndex();
419  assert(Idx < DebugLocInfo.DebugLocations.size() &&
420         "Invalid index into debug locations!");
421  return DebugLocInfo.DebugLocations[Idx];
422}
423
424//===----------------------------------------------------------------------===//
425//  MachineFrameInfo implementation
426//===----------------------------------------------------------------------===//
427
428/// CreateFixedObject - Create a new object at a fixed location on the stack.
429/// All fixed objects should be created before other objects are created for
430/// efficiency. By default, fixed objects are immutable. This returns an
431/// index with a negative value.
432///
433int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
434                                        bool Immutable) {
435  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
436  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
437  return -++NumFixedObjects;
438}
439
440
441void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
442  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
443  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
444
445  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
446    const StackObject &SO = Objects[i];
447    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
448    if (SO.Size == ~0ULL) {
449      OS << "dead\n";
450      continue;
451    }
452    if (SO.Size == 0)
453      OS << "variable sized";
454    else
455      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
456    OS << " alignment is " << SO.Alignment << " byte"
457       << (SO.Alignment != 1 ? "s," : ",");
458
459    if (i < NumFixedObjects)
460      OS << " fixed";
461    if (i < NumFixedObjects || SO.SPOffset != -1) {
462      int64_t Off = SO.SPOffset - ValOffset;
463      OS << " at location [SP";
464      if (Off > 0)
465        OS << "+" << Off;
466      else if (Off < 0)
467        OS << Off;
468      OS << "]";
469    }
470    OS << "\n";
471  }
472
473  if (HasVarSizedObjects)
474    OS << "  Stack frame contains variable sized objects\n";
475}
476
477void MachineFrameInfo::dump(const MachineFunction &MF) const {
478  print(MF, *cerr.stream());
479}
480
481
482//===----------------------------------------------------------------------===//
483//  MachineJumpTableInfo implementation
484//===----------------------------------------------------------------------===//
485
486/// getJumpTableIndex - Create a new jump table entry in the jump table info
487/// or return an existing one.
488///
489unsigned MachineJumpTableInfo::getJumpTableIndex(
490                               const std::vector<MachineBasicBlock*> &DestBBs) {
491  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
492  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
493    if (JumpTables[i].MBBs == DestBBs)
494      return i;
495
496  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
497  return JumpTables.size()-1;
498}
499
500/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
501/// the jump tables to branch to New instead.
502bool
503MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
504                                             MachineBasicBlock *New) {
505  assert(Old != New && "Not making a change?");
506  bool MadeChange = false;
507  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
508    MachineJumpTableEntry &JTE = JumpTables[i];
509    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
510      if (JTE.MBBs[j] == Old) {
511        JTE.MBBs[j] = New;
512        MadeChange = true;
513      }
514  }
515  return MadeChange;
516}
517
518void MachineJumpTableInfo::print(std::ostream &OS) const {
519  // FIXME: this is lame, maybe we could print out the MBB numbers or something
520  // like {1, 2, 4, 5, 3, 0}
521  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
522    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
523       << " entries\n";
524  }
525}
526
527void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
528
529
530//===----------------------------------------------------------------------===//
531//  MachineConstantPool implementation
532//===----------------------------------------------------------------------===//
533
534const Type *MachineConstantPoolEntry::getType() const {
535  if (isMachineConstantPoolEntry())
536      return Val.MachineCPVal->getType();
537  return Val.ConstVal->getType();
538}
539
540MachineConstantPool::~MachineConstantPool() {
541  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
542    if (Constants[i].isMachineConstantPoolEntry())
543      delete Constants[i].Val.MachineCPVal;
544}
545
546/// getConstantPoolIndex - Create a new entry in the constant pool or return
547/// an existing one.  User must specify the log2 of the minimum required
548/// alignment for the object.
549///
550unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
551                                                   unsigned Alignment) {
552  assert(Alignment && "Alignment must be specified!");
553  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
554
555  // Check to see if we already have this constant.
556  //
557  // FIXME, this could be made much more efficient for large constant pools.
558  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
559    if (Constants[i].Val.ConstVal == C &&
560        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
561      return i;
562
563  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
564  return Constants.size()-1;
565}
566
567unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
568                                                   unsigned Alignment) {
569  assert(Alignment && "Alignment must be specified!");
570  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
571
572  // Check to see if we already have this constant.
573  //
574  // FIXME, this could be made much more efficient for large constant pools.
575  int Idx = V->getExistingMachineCPValue(this, Alignment);
576  if (Idx != -1)
577    return (unsigned)Idx;
578
579  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
580  return Constants.size()-1;
581}
582
583void MachineConstantPool::print(raw_ostream &OS) const {
584  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
585    OS << "  <cp#" << i << "> is";
586    if (Constants[i].isMachineConstantPoolEntry())
587      Constants[i].Val.MachineCPVal->print(OS);
588    else
589      OS << *(Value*)Constants[i].Val.ConstVal;
590    OS << " , alignment=" << Constants[i].getAlignment();
591    OS << "\n";
592  }
593}
594
595void MachineConstantPool::dump() const { print(errs()); }
596