MachineFunction.cpp revision 5b02f4c65921e7f0f0cc997aa6f0b614259e4aea 
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  MFInfo = 0;
125  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
126                  MachineFrameInfo(*TM.getFrameInfo());
127  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
128                     MachineConstantPool(TM.getTargetData());
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 Alignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
135                             : TD.getPointerABIAlignment();
136  JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
137                      MachineJumpTableInfo(EntrySize, Alignment);
138}
139
140MachineFunction::~MachineFunction() {
141  BasicBlocks.clear();
142  InstructionRecycler.clear(Allocator);
143  BasicBlockRecycler.clear(Allocator);
144  if (RegInfo)
145    RegInfo->~MachineRegisterInfo();        Allocator.Deallocate(RegInfo);
146  if (MFInfo) {
147    MFInfo->~MachineFunctionInfo();       Allocator.Deallocate(MFInfo);
148  }
149  FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
150  ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
151  JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
152}
153
154
155/// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
156/// recomputes them.  This guarantees that the MBB numbers are sequential,
157/// dense, and match the ordering of the blocks within the function.  If a
158/// specific MachineBasicBlock is specified, only that block and those after
159/// it are renumbered.
160void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
161  if (empty()) { MBBNumbering.clear(); return; }
162  MachineFunction::iterator MBBI, E = end();
163  if (MBB == 0)
164    MBBI = begin();
165  else
166    MBBI = MBB;
167
168  // Figure out the block number this should have.
169  unsigned BlockNo = 0;
170  if (MBBI != begin())
171    BlockNo = prior(MBBI)->getNumber()+1;
172
173  for (; MBBI != E; ++MBBI, ++BlockNo) {
174    if (MBBI->getNumber() != (int)BlockNo) {
175      // Remove use of the old number.
176      if (MBBI->getNumber() != -1) {
177        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
178               "MBB number mismatch!");
179        MBBNumbering[MBBI->getNumber()] = 0;
180      }
181
182      // If BlockNo is already taken, set that block's number to -1.
183      if (MBBNumbering[BlockNo])
184        MBBNumbering[BlockNo]->setNumber(-1);
185
186      MBBNumbering[BlockNo] = MBBI;
187      MBBI->setNumber(BlockNo);
188    }
189  }
190
191  // Okay, all the blocks are renumbered.  If we have compactified the block
192  // numbering, shrink MBBNumbering now.
193  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
194  MBBNumbering.resize(BlockNo);
195}
196
197/// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
198/// of `new MachineInstr'.
199///
200MachineInstr *
201MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
202                                    DebugLoc DL, bool NoImp) {
203  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
204    MachineInstr(TID, DL, NoImp);
205}
206
207/// CloneMachineInstr - Create a new MachineInstr which is a copy of the
208/// 'Orig' instruction, identical in all ways except the the instruction
209/// has no parent, prev, or next.
210///
211MachineInstr *
212MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
213  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
214             MachineInstr(*this, *Orig);
215}
216
217/// DeleteMachineInstr - Delete the given MachineInstr.
218///
219void
220MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
221  // Clear the instructions memoperands. This must be done manually because
222  // the instruction's parent pointer is now null, so it can't properly
223  // deallocate them on its own.
224  MI->clearMemOperands(*this);
225
226  MI->~MachineInstr();
227  InstructionRecycler.Deallocate(Allocator, MI);
228}
229
230/// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
231/// instead of `new MachineBasicBlock'.
232///
233MachineBasicBlock *
234MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
235  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
236             MachineBasicBlock(*this, bb);
237}
238
239/// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
240///
241void
242MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
243  assert(MBB->getParent() == this && "MBB parent mismatch!");
244  MBB->~MachineBasicBlock();
245  BasicBlockRecycler.Deallocate(Allocator, MBB);
246}
247
248void MachineFunction::dump() const {
249  print(*cerr.stream());
250}
251
252void MachineFunction::print(std::ostream &OS) const {
253  OS << "# Machine code for " << Fn->getName () << "():\n";
254
255  // Print Frame Information
256  FrameInfo->print(*this, OS);
257
258  // Print JumpTable Information
259  JumpTableInfo->print(OS);
260
261  // Print Constant Pool
262  {
263    raw_os_ostream OSS(OS);
264    ConstantPool->print(OSS);
265  }
266
267  const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
268
269  if (RegInfo && !RegInfo->livein_empty()) {
270    OS << "Live Ins:";
271    for (MachineRegisterInfo::livein_iterator
272         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
273      if (TRI)
274        OS << " " << TRI->getName(I->first);
275      else
276        OS << " Reg #" << I->first;
277
278      if (I->second)
279        OS << " in VR#" << I->second << " ";
280    }
281    OS << "\n";
282  }
283  if (RegInfo && !RegInfo->liveout_empty()) {
284    OS << "Live Outs:";
285    for (MachineRegisterInfo::liveout_iterator
286         I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
287      if (TRI)
288        OS << " " << TRI->getName(*I);
289      else
290        OS << " Reg #" << *I;
291    OS << "\n";
292  }
293
294  for (const_iterator BB = begin(); BB != end(); ++BB)
295    BB->print(OS);
296
297  OS << "\n# End machine code for " << Fn->getName () << "().\n\n";
298}
299
300/// CFGOnly flag - This is used to control whether or not the CFG graph printer
301/// prints out the contents of basic blocks or not.  This is acceptable because
302/// this code is only really used for debugging purposes.
303///
304static bool CFGOnly = false;
305
306namespace llvm {
307  template<>
308  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
309    static std::string getGraphName(const MachineFunction *F) {
310      return "CFG for '" + F->getFunction()->getName() + "' function";
311    }
312
313    static std::string getNodeLabel(const MachineBasicBlock *Node,
314                                    const MachineFunction *Graph) {
315      if (CFGOnly && Node->getBasicBlock() &&
316          !Node->getBasicBlock()->getName().empty())
317        return Node->getBasicBlock()->getName() + ":";
318
319      std::ostringstream Out;
320      if (CFGOnly) {
321        Out << Node->getNumber() << ':';
322        return Out.str();
323      }
324
325      Node->print(Out);
326
327      std::string OutStr = Out.str();
328      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
329
330      // Process string output to make it nicer...
331      for (unsigned i = 0; i != OutStr.length(); ++i)
332        if (OutStr[i] == '\n') {                            // Left justify
333          OutStr[i] = '\\';
334          OutStr.insert(OutStr.begin()+i+1, 'l');
335        }
336      return OutStr;
337    }
338  };
339}
340
341void MachineFunction::viewCFG() const
342{
343#ifndef NDEBUG
344  ViewGraph(this, "mf" + getFunction()->getName());
345#else
346  cerr << "SelectionDAG::viewGraph is only available in debug builds on "
347       << "systems with Graphviz or gv!\n";
348#endif // NDEBUG
349}
350
351void MachineFunction::viewCFGOnly() const
352{
353  CFGOnly = true;
354  viewCFG();
355  CFGOnly = false;
356}
357
358// The next two methods are used to construct and to retrieve
359// the MachineCodeForFunction object for the given function.
360// construct() -- Allocates and initializes for a given function and target
361// get()       -- Returns a handle to the object.
362//                This should not be called before "construct()"
363//                for a given Function.
364//
365MachineFunction&
366MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
367{
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  bool Deleted = Fn->deleteAnnotation(MF_AID);
377  assert(Deleted && "Machine code did not exist for function!");
378  Deleted = Deleted; // silence warning when no assertions.
379}
380
381MachineFunction& MachineFunction::get(const Function *F)
382{
383  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
384  assert(mc && "Call construct() method first to allocate the object");
385  return *mc;
386}
387
388/// addLiveIn - Add the specified physical register as a live-in value and
389/// create a corresponding virtual register for it.
390unsigned MachineFunction::addLiveIn(unsigned PReg,
391                                    const TargetRegisterClass *RC) {
392  assert(RC->contains(PReg) && "Not the correct regclass!");
393  unsigned VReg = getRegInfo().createVirtualRegister(RC);
394  getRegInfo().addLiveIn(PReg, VReg);
395  return VReg;
396}
397
398/// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
399/// source file, line, and column. If none currently exists, create a new
400/// DebugLocTuple, and insert it into the DebugIdMap.
401unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
402                                                unsigned Line, unsigned Col) {
403  DebugLocTuple Tuple(CompileUnit, Line, Col);
404  DenseMap<DebugLocTuple, unsigned>::iterator II
405    = DebugLocInfo.DebugIdMap.find(Tuple);
406  if (II != DebugLocInfo.DebugIdMap.end())
407    return II->second;
408  // Add a new tuple.
409  unsigned Id = DebugLocInfo.DebugLocations.size();
410  DebugLocInfo.DebugLocations.push_back(Tuple);
411  DebugLocInfo.DebugIdMap[Tuple] = Id;
412  return Id;
413}
414
415/// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
416DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
417  unsigned Idx = DL.getIndex();
418  assert(Idx < DebugLocInfo.DebugLocations.size() &&
419         "Invalid index into debug locations!");
420  return DebugLocInfo.DebugLocations[Idx];
421}
422
423//===----------------------------------------------------------------------===//
424//  MachineFrameInfo implementation
425//===----------------------------------------------------------------------===//
426
427/// CreateFixedObject - Create a new object at a fixed location on the stack.
428/// All fixed objects should be created before other objects are created for
429/// efficiency. By default, fixed objects are immutable. This returns an
430/// index with a negative value.
431///
432int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
433                                        bool Immutable) {
434  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
435  Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
436  return -++NumFixedObjects;
437}
438
439
440void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
441  const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
442  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
443
444  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
445    const StackObject &SO = Objects[i];
446    OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
447    if (SO.Size == ~0ULL) {
448      OS << "dead\n";
449      continue;
450    }
451    if (SO.Size == 0)
452      OS << "variable sized";
453    else
454      OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
455    OS << " alignment is " << SO.Alignment << " byte"
456       << (SO.Alignment != 1 ? "s," : ",");
457
458    if (i < NumFixedObjects)
459      OS << " fixed";
460    if (i < NumFixedObjects || SO.SPOffset != -1) {
461      int64_t Off = SO.SPOffset - ValOffset;
462      OS << " at location [SP";
463      if (Off > 0)
464        OS << "+" << Off;
465      else if (Off < 0)
466        OS << Off;
467      OS << "]";
468    }
469    OS << "\n";
470  }
471
472  if (HasVarSizedObjects)
473    OS << "  Stack frame contains variable sized objects\n";
474}
475
476void MachineFrameInfo::dump(const MachineFunction &MF) const {
477  print(MF, *cerr.stream());
478}
479
480
481//===----------------------------------------------------------------------===//
482//  MachineJumpTableInfo implementation
483//===----------------------------------------------------------------------===//
484
485/// getJumpTableIndex - Create a new jump table entry in the jump table info
486/// or return an existing one.
487///
488unsigned MachineJumpTableInfo::getJumpTableIndex(
489                               const std::vector<MachineBasicBlock*> &DestBBs) {
490  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
491  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
492    if (JumpTables[i].MBBs == DestBBs)
493      return i;
494
495  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
496  return JumpTables.size()-1;
497}
498
499/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
500/// the jump tables to branch to New instead.
501bool
502MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
503                                             MachineBasicBlock *New) {
504  assert(Old != New && "Not making a change?");
505  bool MadeChange = false;
506  for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
507    MachineJumpTableEntry &JTE = JumpTables[i];
508    for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
509      if (JTE.MBBs[j] == Old) {
510        JTE.MBBs[j] = New;
511        MadeChange = true;
512      }
513  }
514  return MadeChange;
515}
516
517void MachineJumpTableInfo::print(std::ostream &OS) const {
518  // FIXME: this is lame, maybe we could print out the MBB numbers or something
519  // like {1, 2, 4, 5, 3, 0}
520  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
521    OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
522       << " entries\n";
523  }
524}
525
526void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
527
528
529//===----------------------------------------------------------------------===//
530//  MachineConstantPool implementation
531//===----------------------------------------------------------------------===//
532
533const Type *MachineConstantPoolEntry::getType() const {
534  if (isMachineConstantPoolEntry())
535      return Val.MachineCPVal->getType();
536  return Val.ConstVal->getType();
537}
538
539MachineConstantPool::~MachineConstantPool() {
540  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
541    if (Constants[i].isMachineConstantPoolEntry())
542      delete Constants[i].Val.MachineCPVal;
543}
544
545/// getConstantPoolIndex - Create a new entry in the constant pool or return
546/// an existing one.  User must specify the log2 of the minimum required
547/// alignment for the object.
548///
549unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
550                                                   unsigned Alignment) {
551  assert(Alignment && "Alignment must be specified!");
552  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
553
554  // Check to see if we already have this constant.
555  //
556  // FIXME, this could be made much more efficient for large constant pools.
557  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
558    if (Constants[i].Val.ConstVal == C &&
559        (Constants[i].getAlignment() & (Alignment - 1)) == 0)
560      return i;
561
562  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
563  return Constants.size()-1;
564}
565
566unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
567                                                   unsigned Alignment) {
568  assert(Alignment && "Alignment must be specified!");
569  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
570
571  // Check to see if we already have this constant.
572  //
573  // FIXME, this could be made much more efficient for large constant pools.
574  int Idx = V->getExistingMachineCPValue(this, Alignment);
575  if (Idx != -1)
576    return (unsigned)Idx;
577
578  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
579  return Constants.size()-1;
580}
581
582void MachineConstantPool::print(raw_ostream &OS) const {
583  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
584    OS << "  <cp#" << i << "> is";
585    if (Constants[i].isMachineConstantPoolEntry())
586      Constants[i].Val.MachineCPVal->print(OS);
587    else
588      OS << *(Value*)Constants[i].Val.ConstVal;
589    OS << " , alignment=" << Constants[i].getAlignment();
590    OS << "\n";
591  }
592}
593
594void MachineConstantPool::dump() const { print(errs()); }
595