MachineFunction.cpp revision dd37b360d7ecc95b4a077bb64cca22b764788751 
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
38bool MachineFunctionPass::runOnFunction(Function &F) {
39  // Do not codegen any 'available_externally' functions at all, they have
40  // definitions outside the translation unit.
41  if (F.hasAvailableExternallyLinkage())
42    return false;
43
44  return runOnMachineFunction(MachineFunction::get(&F));
45}
46
47namespace {
48  struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
49    static char ID;
50
51    std::ostream *OS;
52    const std::string Banner;
53
54    Printer (std::ostream *os, const std::string &banner)
55      : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
56
57    const char *getPassName() const { return "MachineFunction Printer"; }
58
59    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
60      AU.setPreservesAll();
61    }
62
63    bool runOnMachineFunction(MachineFunction &MF) {
64      (*OS) << Banner;
65      MF.print (*OS);
66      return false;
67    }
68  };
69  char Printer::ID = 0;
70}
71
72/// Returns a newly-created MachineFunction Printer pass. The default output
73/// stream is std::cerr; the default banner is empty.
74///
75FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
76                                                     const std::string &Banner){
77  return new Printer(OS, Banner);
78}
79
80namespace {
81  struct VISIBILITY_HIDDEN Deleter : public MachineFunctionPass {
82    static char ID;
83    Deleter() : MachineFunctionPass(&ID) {}
84
85    const char *getPassName() const { return "Machine Code Deleter"; }
86
87    bool runOnMachineFunction(MachineFunction &MF) {
88      // Delete the annotation from the function now.
89      MachineFunction::destruct(MF.getFunction());
90      return true;
91    }
92  };
93  char Deleter::ID = 0;
94}
95
96/// MachineCodeDeletion Pass - This pass deletes all of the machine code for
97/// the current function, which should happen after the function has been
98/// emitted to a .s file or to memory.
99FunctionPass *llvm::createMachineCodeDeleter() {
100  return new Deleter();
101}
102
103
104
105//===---------------------------------------------------------------------===//
106// MachineFunction implementation
107//===---------------------------------------------------------------------===//
108
109void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
110  MBB->getParent()->DeleteMachineBasicBlock(MBB);
111}
112
113MachineFunction::MachineFunction(const Function *F,
114                                 const TargetMachine &TM)
115  : Annotation(AnnotationManager::getID("CodeGen::MachineCodeForFunction")),
116    Fn(F), Target(TM) {
117  if (TM.getRegisterInfo())
118    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
119                  MachineRegisterInfo(*TM.getRegisterInfo());
120  else
121    RegInfo = 0;
122  MFInfo = 0;
123  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
124                  MachineFrameInfo(*TM.getFrameInfo());
125  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
126                     MachineConstantPool(TM.getTargetData());
127
128  // Set up jump table.
129  const TargetData &TD = *TM.getTargetData();
130  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
131  unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
132  unsigned TyAlignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
133                               : TD.getPointerABIAlignment();
134  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
135                      MachineJumpTableInfo(EntrySize, TyAlignment);
136}
137
138MachineFunction::~MachineFunction() {
139  BasicBlocks.clear();
140  InstructionRecycler.clear(Allocator);
141  BasicBlockRecycler.clear(Allocator);
142  if (RegInfo) {
143    RegInfo->~MachineRegisterInfo();
144    Allocator.Deallocate(RegInfo);
145  }
146  if (MFInfo) {
147    MFInfo->~MachineFunctionInfo();
148    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
301namespace llvm {
302  template<>
303  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
304    static std::string getGraphName(const MachineFunction *F) {
305      return "CFG for '" + F->getFunction()->getName() + "' function";
306    }
307
308    static std::string getNodeLabel(const MachineBasicBlock *Node,
309                                    const MachineFunction *Graph,
310                                    bool ShortNames) {
311      if (ShortNames && Node->getBasicBlock() &&
312          !Node->getBasicBlock()->getName().empty())
313        return Node->getBasicBlock()->getName() + ":";
314
315      std::ostringstream Out;
316      if (ShortNames) {
317        Out << Node->getNumber() << ':';
318        return Out.str();
319      }
320
321      Node->print(Out);
322
323      std::string OutStr = Out.str();
324      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
325
326      // Process string output to make it nicer...
327      for (unsigned i = 0; i != OutStr.length(); ++i)
328        if (OutStr[i] == '\n') {                            // Left justify
329          OutStr[i] = '\\';
330          OutStr.insert(OutStr.begin()+i+1, 'l');
331        }
332      return OutStr;
333    }
334  };
335}
336
337void MachineFunction::viewCFG() const
338{
339#ifndef NDEBUG
340  ViewGraph(this, "mf" + getFunction()->getName());
341#else
342  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
343       << "systems with Graphviz or gv!\n";
344#endif // NDEBUG
345}
346
347void MachineFunction::viewCFGOnly() const
348{
349#ifndef NDEBUG
350  ViewGraph(this, "mf" + getFunction()->getName(), true);
351#else
352  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
353       << "systems with Graphviz or gv!\n";
354#endif // NDEBUG
355}
356
357// The next two methods are used to construct and to retrieve
358// the MachineCodeForFunction object for the given function.
359// construct() -- Allocates and initializes for a given function and target
360// get()       -- Returns a handle to the object.
361//                This should not be called before "construct()"
362//                for a given Function.
363//
364MachineFunction&
365MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
366{
367  AnnotationID MF_AID =
368                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
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  AnnotationID MF_AID =
378                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
379  bool Deleted = Fn->deleteAnnotation(MF_AID);
380  assert(Deleted && "Machine code did not exist for function!");
381  Deleted = Deleted; // silence warning when no assertions.
382}
383
384MachineFunction& MachineFunction::get(const Function *F)
385{
386  AnnotationID MF_AID =
387                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
388  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
389  assert(mc && "Call construct() method first to allocate the object");
390  return *mc;
391}
392
393/// addLiveIn - Add the specified physical register as a live-in value and
394/// create a corresponding virtual register for it.
395unsigned MachineFunction::addLiveIn(unsigned PReg,
396                                    const TargetRegisterClass *RC) {
397  assert(RC->contains(PReg) && "Not the correct regclass!");
398  unsigned VReg = getRegInfo().createVirtualRegister(RC);
399  getRegInfo().addLiveIn(PReg, VReg);
400  return VReg;
401}
402
403/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
404/// source file, line, and column. If none currently exists, create a new
405/// DebugLocTuple, and insert it into the DebugIdMap.
406unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
407                                                unsigned Line, unsigned Col) {
408  DebugLocTuple Tuple(CompileUnit, Line, Col);
409  DenseMap<DebugLocTuple, unsigned>::iterator II
410    = DebugLocInfo.DebugIdMap.find(Tuple);
411  if (II != DebugLocInfo.DebugIdMap.end())
412    return II->second;
413  // Add a new tuple.
414  unsigned Id = DebugLocInfo.DebugLocations.size();
415  DebugLocInfo.DebugLocations.push_back(Tuple);
416  DebugLocInfo.DebugIdMap[Tuple] = Id;
417  return Id;
418}
419
420/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
421DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
422  unsigned Idx = DL.getIndex();
423  assert(Idx < DebugLocInfo.DebugLocations.size() &&
424         "Invalid index into debug locations!");
425  return DebugLocInfo.DebugLocations[Idx];
426}
427
428//===----------------------------------------------------------------------===//
429//  MachineFrameInfo implementation
430//===----------------------------------------------------------------------===//
431
432/// CreateFixedObject - Create a new object at a fixed location on the stack.
433/// All fixed objects should be created before other objects are created for
434/// efficiency. By default, fixed objects are immutable. This returns an
435/// index with a negative value.
436///
437int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
438                                        bool Immutable) {
439  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
440  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
441  return -++NumFixedObjects;
442}
443
444
445void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
446  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
447  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
448
449  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
450    const StackObject &SO = Objects[i];
451    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
452    if (SO.Size == ~0ULL) {
453      OS << "dead\n";
454      continue;
455    }
456    if (SO.Size == 0)
457      OS << "variable sized";
458    else
459      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
460    OS << " alignment is " << SO.Alignment << " byte"
461       << (SO.Alignment != 1 ? "s," : ",");
462
463    if (i < NumFixedObjects)
464      OS << " fixed";
465    if (i < NumFixedObjects || SO.SPOffset != -1) {
466      int64_t Off = SO.SPOffset - ValOffset;
467      OS << " at location [SP";
468      if (Off > 0)
469        OS << "+" << Off;
470      else if (Off < 0)
471        OS << Off;
472      OS << "]";
473    }
474    OS << "\n";
475  }
476
477  if (HasVarSizedObjects)
478    OS << "  Stack frame contains variable sized objects\n";
479}
480
481void MachineFrameInfo::dump(const MachineFunction &MF) const {
482  print(MF, *cerr.stream());
483}
484
485
486//===----------------------------------------------------------------------===//
487//  MachineJumpTableInfo implementation
488//===----------------------------------------------------------------------===//
489
490/// getJumpTableIndex - Create a new jump table entry in the jump table info
491/// or return an existing one.
492///
493unsigned MachineJumpTableInfo::getJumpTableIndex(
494                               const std::vector<MachineBasicBlock*> &DestBBs) {
495  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
496  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
497    if (JumpTables[i].MBBs == DestBBs)
498      return i;
499
500  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
501  return JumpTables.size()-1;
502}
503
504/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
505/// the jump tables to branch to New instead.
506bool
507MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
508                                             MachineBasicBlock *New) {
509  assert(Old != New && "Not making a change?");
510  bool MadeChange = false;
511  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
512    MachineJumpTableEntry &JTE = JumpTables[i];
513    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
514      if (JTE.MBBs[j] == Old) {
515        JTE.MBBs[j] = New;
516        MadeChange = true;
517      }
518  }
519  return MadeChange;
520}
521
522void MachineJumpTableInfo::print(std::ostream &OS) const {
523  // FIXME: this is lame, maybe we could print out the MBB numbers or something
524  // like {1, 2, 4, 5, 3, 0}
525  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
526    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
527       << " entries\n";
528  }
529}
530
531void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
532
533
534//===----------------------------------------------------------------------===//
535//  MachineConstantPool implementation
536//===----------------------------------------------------------------------===//
537
538const Type *MachineConstantPoolEntry::getType() const {
539  if (isMachineConstantPoolEntry())
540      return Val.MachineCPVal->getType();
541  return Val.ConstVal->getType();
542}
543
544MachineConstantPool::~MachineConstantPool() {
545  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
546    if (Constants[i].isMachineConstantPoolEntry())
547      delete Constants[i].Val.MachineCPVal;
548}
549
550/// getConstantPoolIndex - Create a new entry in the constant pool or return
551/// an existing one.  User must specify the log2 of the minimum required
552/// alignment for the object.
553///
554unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
555                                                   unsigned Alignment) {
556  assert(Alignment && "Alignment must be specified!");
557  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
558
559  // Check to see if we already have this constant.
560  //
561  // FIXME, this could be made much more efficient for large constant pools.
562  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
563    if (Constants[i].Val.ConstVal == C &&
564        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
565      return i;
566
567  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
568  return Constants.size()-1;
569}
570
571unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
572                                                   unsigned Alignment) {
573  assert(Alignment && "Alignment must be specified!");
574  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
575
576  // Check to see if we already have this constant.
577  //
578  // FIXME, this could be made much more efficient for large constant pools.
579  int Idx = V->getExistingMachineCPValue(this, Alignment);
580  if (Idx != -1)
581    return (unsigned)Idx;
582
583  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
584  return Constants.size()-1;
585}
586
587void MachineConstantPool::print(raw_ostream &OS) const {
588  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
589    OS << "  <cp#" << i << "> is";
590    if (Constants[i].isMachineConstantPoolEntry())
591      Constants[i].Val.MachineCPVal->print(OS);
592    else
593      OS << *(Value*)Constants[i].Val.ConstVal;
594    OS << " , alignment=" << Constants[i].getAlignment();
595    OS << "\n";
596  }
597}
598
599void MachineConstantPool::dump() const { print(errs()); }
600