MachineFunction.cpp revision df7d5d317096c342ee1c459139914965008fbcd7 
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 Alignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
133                             : TD.getPointerABIAlignment();
134  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
135                      MachineJumpTableInfo(EntrySize, Alignment);
136}
137
138MachineFunction::~MachineFunction() {
139  BasicBlocks.clear();
140  InstructionRecycler.clear(Allocator);
141  BasicBlockRecycler.clear(Allocator);
142  if (RegInfo)
143    RegInfo->~MachineRegisterInfo();        Allocator.Deallocate(RegInfo);
144  if (MFInfo) {
145    MFInfo->~MachineFunctionInfo();       Allocator.Deallocate(MFInfo);
146  }
147  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
148  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
149  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
150}
151
152
153/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
154/// recomputes them.  This guarantees that the MBB numbers are sequential,
155/// dense, and match the ordering of the blocks within the function.  If a
156/// specific MachineBasicBlock is specified, only that block and those after
157/// it are renumbered.
158void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
159  if (empty()) { MBBNumbering.clear(); return; }
160  MachineFunction::iterator MBBI, E = end();
161  if (MBB == 0)
162    MBBI = begin();
163  else
164    MBBI = MBB;
165
166  // Figure out the block number this should have.
167  unsigned BlockNo = 0;
168  if (MBBI != begin())
169    BlockNo = prior(MBBI)->getNumber()+1;
170
171  for (; MBBI != E; ++MBBI, ++BlockNo) {
172    if (MBBI->getNumber() != (int)BlockNo) {
173      // Remove use of the old number.
174      if (MBBI->getNumber() != -1) {
175        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
176               "MBB number mismatch!");
177        MBBNumbering[MBBI->getNumber()] = 0;
178      }
179
180      // If BlockNo is already taken, set that block's number to -1.
181      if (MBBNumbering[BlockNo])
182        MBBNumbering[BlockNo]->setNumber(-1);
183
184      MBBNumbering[BlockNo] = MBBI;
185      MBBI->setNumber(BlockNo);
186    }
187  }
188
189  // Okay, all the blocks are renumbered.  If we have compactified the block
190  // numbering, shrink MBBNumbering now.
191  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
192  MBBNumbering.resize(BlockNo);
193}
194
195/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
196/// of `new MachineInstr'.
197///
198MachineInstr *
199MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
200                                    DebugLoc DL, bool NoImp) {
201  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
202    MachineInstr(TID, DL, NoImp);
203}
204
205/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
206/// 'Orig' instruction, identical in all ways except the the instruction
207/// has no parent, prev, or next.
208///
209MachineInstr *
210MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
211  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
212             MachineInstr(*this, *Orig);
213}
214
215/// DeleteMachineInstr - Delete the given MachineInstr.
216///
217void
218MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
219  // Clear the instructions memoperands. This must be done manually because
220  // the instruction's parent pointer is now null, so it can't properly
221  // deallocate them on its own.
222  MI->clearMemOperands(*this);
223
224  MI->~MachineInstr();
225  InstructionRecycler.Deallocate(Allocator, MI);
226}
227
228/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
229/// instead of `new MachineBasicBlock'.
230///
231MachineBasicBlock *
232MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
233  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
234             MachineBasicBlock(*this, bb);
235}
236
237/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
238///
239void
240MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
241  assert(MBB->getParent() == this && "MBB parent mismatch!");
242  MBB->~MachineBasicBlock();
243  BasicBlockRecycler.Deallocate(Allocator, MBB);
244}
245
246void MachineFunction::dump() const {
247  print(*cerr.stream());
248}
249
250void MachineFunction::print(std::ostream &OS) const {
251  OS << "# Machine code for " << Fn->getName () << "():\n";
252
253  // Print Frame Information
254  FrameInfo->print(*this, OS);
255
256  // Print JumpTable Information
257  JumpTableInfo->print(OS);
258
259  // Print Constant Pool
260  {
261    raw_os_ostream OSS(OS);
262    ConstantPool->print(OSS);
263  }
264
265  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
266
267  if (RegInfo && !RegInfo->livein_empty()) {
268    OS << "Live Ins:";
269    for (MachineRegisterInfo::livein_iterator
270         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
271      if (TRI)
272        OS << " " << TRI->getName(I->first);
273      else
274        OS << " Reg #" << I->first;
275
276      if (I->second)
277        OS << " in VR#" << I->second << " ";
278    }
279    OS << "\n";
280  }
281  if (RegInfo && !RegInfo->liveout_empty()) {
282    OS << "Live Outs:";
283    for (MachineRegisterInfo::liveout_iterator
284         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
285      if (TRI)
286        OS << " " << TRI->getName(*I);
287      else
288        OS << " Reg #" << *I;
289    OS << "\n";
290  }
291
292  for (const_iterator BB = begin(); BB != end(); ++BB)
293    BB->print(OS);
294
295  OS << "\n# End machine code for " << Fn->getName () << "().\n\n";
296}
297
298/// CFGOnly flag - This is used to control whether or not the CFG graph printer
299/// prints out the contents of basic blocks or not.  This is acceptable because
300/// this code is only really used for debugging purposes.
301///
302static bool CFGOnly = false;
303
304namespace llvm {
305  template<>
306  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
307    static std::string getGraphName(const MachineFunction *F) {
308      return "CFG for '" + F->getFunction()->getName() + "' function";
309    }
310
311    static std::string getNodeLabel(const MachineBasicBlock *Node,
312                                    const MachineFunction *Graph) {
313      if (CFGOnly && Node->getBasicBlock() &&
314          !Node->getBasicBlock()->getName().empty())
315        return Node->getBasicBlock()->getName() + ":";
316
317      std::ostringstream Out;
318      if (CFGOnly) {
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  CFGOnly = true;
352  viewCFG();
353  CFGOnly = false;
354}
355
356// The next two methods are used to construct and to retrieve
357// the MachineCodeForFunction object for the given function.
358// construct() -- Allocates and initializes for a given function and target
359// get()       -- Returns a handle to the object.
360//                This should not be called before "construct()"
361//                for a given Function.
362//
363MachineFunction&
364MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
365{
366  AnnotationID MF_AID =
367                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
368  assert(Fn->getAnnotation(MF_AID) == 0 &&
369         "Object already exists for this function!");
370  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
371  Fn->addAnnotation(mcInfo);
372  return *mcInfo;
373}
374
375void MachineFunction::destruct(const Function *Fn) {
376  AnnotationID MF_AID =
377                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
378  bool Deleted = Fn->deleteAnnotation(MF_AID);
379  assert(Deleted && "Machine code did not exist for function!");
380  Deleted = Deleted; // silence warning when no assertions.
381}
382
383MachineFunction& MachineFunction::get(const Function *F)
384{
385  AnnotationID MF_AID =
386                    AnnotationManager::getID("CodeGen::MachineCodeForFunction");
387  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
388  assert(mc && "Call construct() method first to allocate the object");
389  return *mc;
390}
391
392/// addLiveIn - Add the specified physical register as a live-in value and
393/// create a corresponding virtual register for it.
394unsigned MachineFunction::addLiveIn(unsigned PReg,
395                                    const TargetRegisterClass *RC) {
396  assert(RC->contains(PReg) && "Not the correct regclass!");
397  unsigned VReg = getRegInfo().createVirtualRegister(RC);
398  getRegInfo().addLiveIn(PReg, VReg);
399  return VReg;
400}
401
402/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
403/// source file, line, and column. If none currently exists, create a new
404/// DebugLocTuple, and insert it into the DebugIdMap.
405unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
406                                                unsigned Line, unsigned Col) {
407  DebugLocTuple Tuple(CompileUnit, Line, Col);
408  DenseMap<DebugLocTuple, unsigned>::iterator II
409    = DebugLocInfo.DebugIdMap.find(Tuple);
410  if (II != DebugLocInfo.DebugIdMap.end())
411    return II->second;
412  // Add a new tuple.
413  unsigned Id = DebugLocInfo.DebugLocations.size();
414  DebugLocInfo.DebugLocations.push_back(Tuple);
415  DebugLocInfo.DebugIdMap[Tuple] = Id;
416  return Id;
417}
418
419/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
420DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
421  unsigned Idx = DL.getIndex();
422  assert(Idx < DebugLocInfo.DebugLocations.size() &&
423         "Invalid index into debug locations!");
424  return DebugLocInfo.DebugLocations[Idx];
425}
426
427//===----------------------------------------------------------------------===//
428//  MachineFrameInfo implementation
429//===----------------------------------------------------------------------===//
430
431/// CreateFixedObject - Create a new object at a fixed location on the stack.
432/// All fixed objects should be created before other objects are created for
433/// efficiency. By default, fixed objects are immutable. This returns an
434/// index with a negative value.
435///
436int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
437                                        bool Immutable) {
438  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
439  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
440  return -++NumFixedObjects;
441}
442
443
444void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
445  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
446  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
447
448  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
449    const StackObject &SO = Objects[i];
450    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
451    if (SO.Size == ~0ULL) {
452      OS << "dead\n";
453      continue;
454    }
455    if (SO.Size == 0)
456      OS << "variable sized";
457    else
458      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
459    OS << " alignment is " << SO.Alignment << " byte"
460       << (SO.Alignment != 1 ? "s," : ",");
461
462    if (i < NumFixedObjects)
463      OS << " fixed";
464    if (i < NumFixedObjects || SO.SPOffset != -1) {
465      int64_t Off = SO.SPOffset - ValOffset;
466      OS << " at location [SP";
467      if (Off > 0)
468        OS << "+" << Off;
469      else if (Off < 0)
470        OS << Off;
471      OS << "]";
472    }
473    OS << "\n";
474  }
475
476  if (HasVarSizedObjects)
477    OS << "  Stack frame contains variable sized objects\n";
478}
479
480void MachineFrameInfo::dump(const MachineFunction &MF) const {
481  print(MF, *cerr.stream());
482}
483
484
485//===----------------------------------------------------------------------===//
486//  MachineJumpTableInfo implementation
487//===----------------------------------------------------------------------===//
488
489/// getJumpTableIndex - Create a new jump table entry in the jump table info
490/// or return an existing one.
491///
492unsigned MachineJumpTableInfo::getJumpTableIndex(
493                               const std::vector<MachineBasicBlock*> &DestBBs) {
494  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
495  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
496    if (JumpTables[i].MBBs == DestBBs)
497      return i;
498
499  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
500  return JumpTables.size()-1;
501}
502
503/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
504/// the jump tables to branch to New instead.
505bool
506MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
507                                             MachineBasicBlock *New) {
508  assert(Old != New && "Not making a change?");
509  bool MadeChange = false;
510  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
511    MachineJumpTableEntry &JTE = JumpTables[i];
512    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
513      if (JTE.MBBs[j] == Old) {
514        JTE.MBBs[j] = New;
515        MadeChange = true;
516      }
517  }
518  return MadeChange;
519}
520
521void MachineJumpTableInfo::print(std::ostream &OS) const {
522  // FIXME: this is lame, maybe we could print out the MBB numbers or something
523  // like {1, 2, 4, 5, 3, 0}
524  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
525    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
526       << " entries\n";
527  }
528}
529
530void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
531
532
533//===----------------------------------------------------------------------===//
534//  MachineConstantPool implementation
535//===----------------------------------------------------------------------===//
536
537const Type *MachineConstantPoolEntry::getType() const {
538  if (isMachineConstantPoolEntry())
539      return Val.MachineCPVal->getType();
540  return Val.ConstVal->getType();
541}
542
543MachineConstantPool::~MachineConstantPool() {
544  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
545    if (Constants[i].isMachineConstantPoolEntry())
546      delete Constants[i].Val.MachineCPVal;
547}
548
549/// getConstantPoolIndex - Create a new entry in the constant pool or return
550/// an existing one.  User must specify the log2 of the minimum required
551/// alignment for the object.
552///
553unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
554                                                   unsigned Alignment) {
555  assert(Alignment && "Alignment must be specified!");
556  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
557
558  // Check to see if we already have this constant.
559  //
560  // FIXME, this could be made much more efficient for large constant pools.
561  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
562    if (Constants[i].Val.ConstVal == C &&
563        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
564      return i;
565
566  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
567  return Constants.size()-1;
568}
569
570unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
571                                                   unsigned Alignment) {
572  assert(Alignment && "Alignment must be specified!");
573  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
574
575  // Check to see if we already have this constant.
576  //
577  // FIXME, this could be made much more efficient for large constant pools.
578  int Idx = V->getExistingMachineCPValue(this, Alignment);
579  if (Idx != -1)
580    return (unsigned)Idx;
581
582  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
583  return Constants.size()-1;
584}
585
586void MachineConstantPool::print(raw_ostream &OS) const {
587  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
588    OS << "  <cp#" << i << "> is";
589    if (Constants[i].isMachineConstantPoolEntry())
590      Constants[i].Val.MachineCPVal->print(OS);
591    else
592      OS << *(Value*)Constants[i].Val.ConstVal;
593    OS << " , alignment=" << Constants[i].getAlignment();
594    OS << "\n";
595  }
596}
597
598void MachineConstantPool::dump() const { print(errs()); }
599