MachineFunction.cpp revision 296417 
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/CodeGen/MachineFunction.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/SmallString.h"
19#include "llvm/Analysis/ConstantFolding.h"
20#include "llvm/Analysis/EHPersonalities.h"
21#include "llvm/CodeGen/MachineConstantPool.h"
22#include "llvm/CodeGen/MachineFrameInfo.h"
23#include "llvm/CodeGen/MachineFunctionInitializer.h"
24#include "llvm/CodeGen/MachineFunctionPass.h"
25#include "llvm/CodeGen/MachineInstr.h"
26#include "llvm/CodeGen/MachineJumpTableInfo.h"
27#include "llvm/CodeGen/MachineModuleInfo.h"
28#include "llvm/CodeGen/MachineRegisterInfo.h"
29#include "llvm/CodeGen/Passes.h"
30#include "llvm/CodeGen/PseudoSourceValue.h"
31#include "llvm/CodeGen/WinEHFuncInfo.h"
32#include "llvm/IR/DataLayout.h"
33#include "llvm/IR/DebugInfo.h"
34#include "llvm/IR/Function.h"
35#include "llvm/IR/Module.h"
36#include "llvm/IR/ModuleSlotTracker.h"
37#include "llvm/MC/MCAsmInfo.h"
38#include "llvm/MC/MCContext.h"
39#include "llvm/Support/Debug.h"
40#include "llvm/Support/GraphWriter.h"
41#include "llvm/Support/raw_ostream.h"
42#include "llvm/Target/TargetFrameLowering.h"
43#include "llvm/Target/TargetLowering.h"
44#include "llvm/Target/TargetMachine.h"
45#include "llvm/Target/TargetSubtargetInfo.h"
46using namespace llvm;
47
48#define DEBUG_TYPE "codegen"
49
50static cl::opt<unsigned>
51    AlignAllFunctions("align-all-functions",
52                      cl::desc("Force the alignment of all functions."),
53                      cl::init(0), cl::Hidden);
54
55void MachineFunctionInitializer::anchor() {}
56
57//===----------------------------------------------------------------------===//
58// MachineFunction implementation
59//===----------------------------------------------------------------------===//
60
61// Out-of-line virtual method.
62MachineFunctionInfo::~MachineFunctionInfo() {}
63
64void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
65  MBB->getParent()->DeleteMachineBasicBlock(MBB);
66}
67
68MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
69                                 unsigned FunctionNum, MachineModuleInfo &mmi)
70    : Fn(F), Target(TM), STI(TM.getSubtargetImpl(*F)), Ctx(mmi.getContext()),
71      MMI(mmi) {
72  if (STI->getRegisterInfo())
73    RegInfo = new (Allocator) MachineRegisterInfo(this);
74  else
75    RegInfo = nullptr;
76
77  MFInfo = nullptr;
78  FrameInfo = new (Allocator)
79      MachineFrameInfo(STI->getFrameLowering()->getStackAlignment(),
80                       STI->getFrameLowering()->isStackRealignable(),
81                       !F->hasFnAttribute("no-realign-stack"));
82
83  if (Fn->hasFnAttribute(Attribute::StackAlignment))
84    FrameInfo->ensureMaxAlignment(Fn->getFnStackAlignment());
85
86  ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
87  Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
88
89  // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
90  // FIXME: Use Function::optForSize().
91  if (!Fn->hasFnAttribute(Attribute::OptimizeForSize))
92    Alignment = std::max(Alignment,
93                         STI->getTargetLowering()->getPrefFunctionAlignment());
94
95  if (AlignAllFunctions)
96    Alignment = AlignAllFunctions;
97
98  FunctionNumber = FunctionNum;
99  JumpTableInfo = nullptr;
100
101  if (isFuncletEHPersonality(classifyEHPersonality(
102          F->hasPersonalityFn() ? F->getPersonalityFn() : nullptr))) {
103    WinEHInfo = new (Allocator) WinEHFuncInfo();
104  }
105
106  assert(TM.isCompatibleDataLayout(getDataLayout()) &&
107         "Can't create a MachineFunction using a Module with a "
108         "Target-incompatible DataLayout attached\n");
109
110  PSVManager = llvm::make_unique<PseudoSourceValueManager>();
111}
112
113MachineFunction::~MachineFunction() {
114  // Don't call destructors on MachineInstr and MachineOperand. All of their
115  // memory comes from the BumpPtrAllocator which is about to be purged.
116  //
117  // Do call MachineBasicBlock destructors, it contains std::vectors.
118  for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
119    I->Insts.clearAndLeakNodesUnsafely();
120
121  InstructionRecycler.clear(Allocator);
122  OperandRecycler.clear(Allocator);
123  BasicBlockRecycler.clear(Allocator);
124  if (RegInfo) {
125    RegInfo->~MachineRegisterInfo();
126    Allocator.Deallocate(RegInfo);
127  }
128  if (MFInfo) {
129    MFInfo->~MachineFunctionInfo();
130    Allocator.Deallocate(MFInfo);
131  }
132
133  FrameInfo->~MachineFrameInfo();
134  Allocator.Deallocate(FrameInfo);
135
136  ConstantPool->~MachineConstantPool();
137  Allocator.Deallocate(ConstantPool);
138
139  if (JumpTableInfo) {
140    JumpTableInfo->~MachineJumpTableInfo();
141    Allocator.Deallocate(JumpTableInfo);
142  }
143
144  if (WinEHInfo) {
145    WinEHInfo->~WinEHFuncInfo();
146    Allocator.Deallocate(WinEHInfo);
147  }
148}
149
150const DataLayout &MachineFunction::getDataLayout() const {
151  return Fn->getParent()->getDataLayout();
152}
153
154/// Get the JumpTableInfo for this function.
155/// If it does not already exist, allocate one.
156MachineJumpTableInfo *MachineFunction::
157getOrCreateJumpTableInfo(unsigned EntryKind) {
158  if (JumpTableInfo) return JumpTableInfo;
159
160  JumpTableInfo = new (Allocator)
161    MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
162  return JumpTableInfo;
163}
164
165/// Should we be emitting segmented stack stuff for the function
166bool MachineFunction::shouldSplitStack() const {
167  return getFunction()->hasFnAttribute("split-stack");
168}
169
170/// This discards all of the MachineBasicBlock numbers and recomputes them.
171/// This guarantees that the MBB numbers are sequential, dense, and match the
172/// ordering of the blocks within the function.  If a specific MachineBasicBlock
173/// is specified, only that block and those after it are renumbered.
174void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
175  if (empty()) { MBBNumbering.clear(); return; }
176  MachineFunction::iterator MBBI, E = end();
177  if (MBB == nullptr)
178    MBBI = begin();
179  else
180    MBBI = MBB->getIterator();
181
182  // Figure out the block number this should have.
183  unsigned BlockNo = 0;
184  if (MBBI != begin())
185    BlockNo = std::prev(MBBI)->getNumber() + 1;
186
187  for (; MBBI != E; ++MBBI, ++BlockNo) {
188    if (MBBI->getNumber() != (int)BlockNo) {
189      // Remove use of the old number.
190      if (MBBI->getNumber() != -1) {
191        assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
192               "MBB number mismatch!");
193        MBBNumbering[MBBI->getNumber()] = nullptr;
194      }
195
196      // If BlockNo is already taken, set that block's number to -1.
197      if (MBBNumbering[BlockNo])
198        MBBNumbering[BlockNo]->setNumber(-1);
199
200      MBBNumbering[BlockNo] = &*MBBI;
201      MBBI->setNumber(BlockNo);
202    }
203  }
204
205  // Okay, all the blocks are renumbered.  If we have compactified the block
206  // numbering, shrink MBBNumbering now.
207  assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
208  MBBNumbering.resize(BlockNo);
209}
210
211/// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
212MachineInstr *
213MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
214                                    DebugLoc DL, bool NoImp) {
215  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
216    MachineInstr(*this, MCID, DL, NoImp);
217}
218
219/// Create a new MachineInstr which is a copy of the 'Orig' instruction,
220/// identical in all ways except the instruction has no parent, prev, or next.
221MachineInstr *
222MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
223  return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
224             MachineInstr(*this, *Orig);
225}
226
227/// Delete the given MachineInstr.
228///
229/// This function also serves as the MachineInstr destructor - the real
230/// ~MachineInstr() destructor must be empty.
231void
232MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
233  // Strip it for parts. The operand array and the MI object itself are
234  // independently recyclable.
235  if (MI->Operands)
236    deallocateOperandArray(MI->CapOperands, MI->Operands);
237  // Don't call ~MachineInstr() which must be trivial anyway because
238  // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
239  // destructors.
240  InstructionRecycler.Deallocate(Allocator, MI);
241}
242
243/// Allocate a new MachineBasicBlock. Use this instead of
244/// `new MachineBasicBlock'.
245MachineBasicBlock *
246MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
247  return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
248             MachineBasicBlock(*this, bb);
249}
250
251/// Delete the given MachineBasicBlock.
252void
253MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
254  assert(MBB->getParent() == this && "MBB parent mismatch!");
255  MBB->~MachineBasicBlock();
256  BasicBlockRecycler.Deallocate(Allocator, MBB);
257}
258
259MachineMemOperand *
260MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
261                                      uint64_t s, unsigned base_alignment,
262                                      const AAMDNodes &AAInfo,
263                                      const MDNode *Ranges) {
264  return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
265                                           AAInfo, Ranges);
266}
267
268MachineMemOperand *
269MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
270                                      int64_t Offset, uint64_t Size) {
271  if (MMO->getValue())
272    return new (Allocator)
273               MachineMemOperand(MachinePointerInfo(MMO->getValue(),
274                                                    MMO->getOffset()+Offset),
275                                 MMO->getFlags(), Size,
276                                 MMO->getBaseAlignment());
277  return new (Allocator)
278             MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(),
279                                                  MMO->getOffset()+Offset),
280                               MMO->getFlags(), Size,
281                               MMO->getBaseAlignment());
282}
283
284MachineInstr::mmo_iterator
285MachineFunction::allocateMemRefsArray(unsigned long Num) {
286  return Allocator.Allocate<MachineMemOperand *>(Num);
287}
288
289std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
290MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
291                                    MachineInstr::mmo_iterator End) {
292  // Count the number of load mem refs.
293  unsigned Num = 0;
294  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
295    if ((*I)->isLoad())
296      ++Num;
297
298  // Allocate a new array and populate it with the load information.
299  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
300  unsigned Index = 0;
301  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
302    if ((*I)->isLoad()) {
303      if (!(*I)->isStore())
304        // Reuse the MMO.
305        Result[Index] = *I;
306      else {
307        // Clone the MMO and unset the store flag.
308        MachineMemOperand *JustLoad =
309          getMachineMemOperand((*I)->getPointerInfo(),
310                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
311                               (*I)->getSize(), (*I)->getBaseAlignment(),
312                               (*I)->getAAInfo());
313        Result[Index] = JustLoad;
314      }
315      ++Index;
316    }
317  }
318  return std::make_pair(Result, Result + Num);
319}
320
321std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
322MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
323                                     MachineInstr::mmo_iterator End) {
324  // Count the number of load mem refs.
325  unsigned Num = 0;
326  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
327    if ((*I)->isStore())
328      ++Num;
329
330  // Allocate a new array and populate it with the store information.
331  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
332  unsigned Index = 0;
333  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
334    if ((*I)->isStore()) {
335      if (!(*I)->isLoad())
336        // Reuse the MMO.
337        Result[Index] = *I;
338      else {
339        // Clone the MMO and unset the load flag.
340        MachineMemOperand *JustStore =
341          getMachineMemOperand((*I)->getPointerInfo(),
342                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
343                               (*I)->getSize(), (*I)->getBaseAlignment(),
344                               (*I)->getAAInfo());
345        Result[Index] = JustStore;
346      }
347      ++Index;
348    }
349  }
350  return std::make_pair(Result, Result + Num);
351}
352
353const char *MachineFunction::createExternalSymbolName(StringRef Name) {
354  char *Dest = Allocator.Allocate<char>(Name.size() + 1);
355  std::copy(Name.begin(), Name.end(), Dest);
356  Dest[Name.size()] = 0;
357  return Dest;
358}
359
360#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
361void MachineFunction::dump() const {
362  print(dbgs());
363}
364#endif
365
366StringRef MachineFunction::getName() const {
367  assert(getFunction() && "No function!");
368  return getFunction()->getName();
369}
370
371void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
372  OS << "# Machine code for function " << getName() << ": ";
373  if (RegInfo) {
374    OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
375    if (!RegInfo->tracksLiveness())
376      OS << ", not tracking liveness";
377  }
378  OS << '\n';
379
380  // Print Frame Information
381  FrameInfo->print(*this, OS);
382
383  // Print JumpTable Information
384  if (JumpTableInfo)
385    JumpTableInfo->print(OS);
386
387  // Print Constant Pool
388  ConstantPool->print(OS);
389
390  const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
391
392  if (RegInfo && !RegInfo->livein_empty()) {
393    OS << "Function Live Ins: ";
394    for (MachineRegisterInfo::livein_iterator
395         I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
396      OS << PrintReg(I->first, TRI);
397      if (I->second)
398        OS << " in " << PrintReg(I->second, TRI);
399      if (std::next(I) != E)
400        OS << ", ";
401    }
402    OS << '\n';
403  }
404
405  ModuleSlotTracker MST(getFunction()->getParent());
406  MST.incorporateFunction(*getFunction());
407  for (const auto &BB : *this) {
408    OS << '\n';
409    BB.print(OS, MST, Indexes);
410  }
411
412  OS << "\n# End machine code for function " << getName() << ".\n\n";
413}
414
415namespace llvm {
416  template<>
417  struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
418
419  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
420
421    static std::string getGraphName(const MachineFunction *F) {
422      return ("CFG for '" + F->getName() + "' function").str();
423    }
424
425    std::string getNodeLabel(const MachineBasicBlock *Node,
426                             const MachineFunction *Graph) {
427      std::string OutStr;
428      {
429        raw_string_ostream OSS(OutStr);
430
431        if (isSimple()) {
432          OSS << "BB#" << Node->getNumber();
433          if (const BasicBlock *BB = Node->getBasicBlock())
434            OSS << ": " << BB->getName();
435        } else
436          Node->print(OSS);
437      }
438
439      if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
440
441      // Process string output to make it nicer...
442      for (unsigned i = 0; i != OutStr.length(); ++i)
443        if (OutStr[i] == '\n') {                            // Left justify
444          OutStr[i] = '\\';
445          OutStr.insert(OutStr.begin()+i+1, 'l');
446        }
447      return OutStr;
448    }
449  };
450}
451
452void MachineFunction::viewCFG() const
453{
454#ifndef NDEBUG
455  ViewGraph(this, "mf" + getName());
456#else
457  errs() << "MachineFunction::viewCFG is only available in debug builds on "
458         << "systems with Graphviz or gv!\n";
459#endif // NDEBUG
460}
461
462void MachineFunction::viewCFGOnly() const
463{
464#ifndef NDEBUG
465  ViewGraph(this, "mf" + getName(), true);
466#else
467  errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
468         << "systems with Graphviz or gv!\n";
469#endif // NDEBUG
470}
471
472/// Add the specified physical register as a live-in value and
473/// create a corresponding virtual register for it.
474unsigned MachineFunction::addLiveIn(unsigned PReg,
475                                    const TargetRegisterClass *RC) {
476  MachineRegisterInfo &MRI = getRegInfo();
477  unsigned VReg = MRI.getLiveInVirtReg(PReg);
478  if (VReg) {
479    const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
480    (void)VRegRC;
481    // A physical register can be added several times.
482    // Between two calls, the register class of the related virtual register
483    // may have been constrained to match some operation constraints.
484    // In that case, check that the current register class includes the
485    // physical register and is a sub class of the specified RC.
486    assert((VRegRC == RC || (VRegRC->contains(PReg) &&
487                             RC->hasSubClassEq(VRegRC))) &&
488            "Register class mismatch!");
489    return VReg;
490  }
491  VReg = MRI.createVirtualRegister(RC);
492  MRI.addLiveIn(PReg, VReg);
493  return VReg;
494}
495
496/// Return the MCSymbol for the specified non-empty jump table.
497/// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
498/// normal 'L' label is returned.
499MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
500                                        bool isLinkerPrivate) const {
501  const DataLayout &DL = getDataLayout();
502  assert(JumpTableInfo && "No jump tables");
503  assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
504
505  const char *Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
506                                       : DL.getPrivateGlobalPrefix();
507  SmallString<60> Name;
508  raw_svector_ostream(Name)
509    << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
510  return Ctx.getOrCreateSymbol(Name);
511}
512
513/// Return a function-local symbol to represent the PIC base.
514MCSymbol *MachineFunction::getPICBaseSymbol() const {
515  const DataLayout &DL = getDataLayout();
516  return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
517                               Twine(getFunctionNumber()) + "$pb");
518}
519
520//===----------------------------------------------------------------------===//
521//  MachineFrameInfo implementation
522//===----------------------------------------------------------------------===//
523
524/// Make sure the function is at least Align bytes aligned.
525void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
526  if (!StackRealignable || !RealignOption)
527    assert(Align <= StackAlignment &&
528           "For targets without stack realignment, Align is out of limit!");
529  if (MaxAlignment < Align) MaxAlignment = Align;
530}
531
532/// Clamp the alignment if requested and emit a warning.
533static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
534                                           unsigned StackAlign) {
535  if (!ShouldClamp || Align <= StackAlign)
536    return Align;
537  DEBUG(dbgs() << "Warning: requested alignment " << Align
538               << " exceeds the stack alignment " << StackAlign
539               << " when stack realignment is off" << '\n');
540  return StackAlign;
541}
542
543/// Create a new statically sized stack object, returning a nonnegative
544/// identifier to represent it.
545int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
546                      bool isSS, const AllocaInst *Alloca) {
547  assert(Size != 0 && "Cannot allocate zero size stack objects!");
548  Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
549                                  Alignment, StackAlignment);
550  Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, Alloca,
551                                !isSS));
552  int Index = (int)Objects.size() - NumFixedObjects - 1;
553  assert(Index >= 0 && "Bad frame index!");
554  ensureMaxAlignment(Alignment);
555  return Index;
556}
557
558/// Create a new statically sized stack object that represents a spill slot,
559/// returning a nonnegative identifier to represent it.
560int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
561                                             unsigned Alignment) {
562  Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
563                                  Alignment, StackAlignment);
564  CreateStackObject(Size, Alignment, true);
565  int Index = (int)Objects.size() - NumFixedObjects - 1;
566  ensureMaxAlignment(Alignment);
567  return Index;
568}
569
570/// Notify the MachineFrameInfo object that a variable sized object has been
571/// created. This must be created whenever a variable sized object is created,
572/// whether or not the index returned is actually used.
573int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment,
574                                                const AllocaInst *Alloca) {
575  HasVarSizedObjects = true;
576  Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
577                                  Alignment, StackAlignment);
578  Objects.push_back(StackObject(0, Alignment, 0, false, false, Alloca, true));
579  ensureMaxAlignment(Alignment);
580  return (int)Objects.size()-NumFixedObjects-1;
581}
582
583/// Create a new object at a fixed location on the stack.
584/// All fixed objects should be created before other objects are created for
585/// efficiency. By default, fixed objects are immutable. This returns an
586/// index with a negative value.
587int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
588                                        bool Immutable, bool isAliased) {
589  assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
590  // The alignment of the frame index can be determined from its offset from
591  // the incoming frame position.  If the frame object is at offset 32 and
592  // the stack is guaranteed to be 16-byte aligned, then we know that the
593  // object is 16-byte aligned.
594  unsigned Align = MinAlign(SPOffset, StackAlignment);
595  Align = clampStackAlignment(!StackRealignable || !RealignOption, Align,
596                              StackAlignment);
597  Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
598                                              /*isSS*/   false,
599                                              /*Alloca*/ nullptr, isAliased));
600  return -++NumFixedObjects;
601}
602
603/// Create a spill slot at a fixed location on the stack.
604/// Returns an index with a negative value.
605int MachineFrameInfo::CreateFixedSpillStackObject(uint64_t Size,
606                                                  int64_t SPOffset) {
607  unsigned Align = MinAlign(SPOffset, StackAlignment);
608  Align = clampStackAlignment(!StackRealignable || !RealignOption, Align,
609                              StackAlignment);
610  Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset,
611                                              /*Immutable*/ true,
612                                              /*isSS*/ true,
613                                              /*Alloca*/ nullptr,
614                                              /*isAliased*/ false));
615  return -++NumFixedObjects;
616}
617
618BitVector MachineFrameInfo::getPristineRegs(const MachineFunction &MF) const {
619  const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
620  BitVector BV(TRI->getNumRegs());
621
622  // Before CSI is calculated, no registers are considered pristine. They can be
623  // freely used and PEI will make sure they are saved.
624  if (!isCalleeSavedInfoValid())
625    return BV;
626
627  for (const MCPhysReg *CSR = TRI->getCalleeSavedRegs(&MF); CSR && *CSR; ++CSR)
628    BV.set(*CSR);
629
630  // Saved CSRs are not pristine.
631  for (auto &I : getCalleeSavedInfo())
632    for (MCSubRegIterator S(I.getReg(), TRI, true); S.isValid(); ++S)
633      BV.reset(*S);
634
635  return BV;
636}
637
638unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
639  const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();
640  const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
641  unsigned MaxAlign = getMaxAlignment();
642  int Offset = 0;
643
644  // This code is very, very similar to PEI::calculateFrameObjectOffsets().
645  // It really should be refactored to share code. Until then, changes
646  // should keep in mind that there's tight coupling between the two.
647
648  for (int i = getObjectIndexBegin(); i != 0; ++i) {
649    int FixedOff = -getObjectOffset(i);
650    if (FixedOff > Offset) Offset = FixedOff;
651  }
652  for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
653    if (isDeadObjectIndex(i))
654      continue;
655    Offset += getObjectSize(i);
656    unsigned Align = getObjectAlignment(i);
657    // Adjust to alignment boundary
658    Offset = (Offset+Align-1)/Align*Align;
659
660    MaxAlign = std::max(Align, MaxAlign);
661  }
662
663  if (adjustsStack() && TFI->hasReservedCallFrame(MF))
664    Offset += getMaxCallFrameSize();
665
666  // Round up the size to a multiple of the alignment.  If the function has
667  // any calls or alloca's, align to the target's StackAlignment value to
668  // ensure that the callee's frame or the alloca data is suitably aligned;
669  // otherwise, for leaf functions, align to the TransientStackAlignment
670  // value.
671  unsigned StackAlign;
672  if (adjustsStack() || hasVarSizedObjects() ||
673      (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
674    StackAlign = TFI->getStackAlignment();
675  else
676    StackAlign = TFI->getTransientStackAlignment();
677
678  // If the frame pointer is eliminated, all frame offsets will be relative to
679  // SP not FP. Align to MaxAlign so this works.
680  StackAlign = std::max(StackAlign, MaxAlign);
681  unsigned AlignMask = StackAlign - 1;
682  Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
683
684  return (unsigned)Offset;
685}
686
687void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
688  if (Objects.empty()) return;
689
690  const TargetFrameLowering *FI = MF.getSubtarget().getFrameLowering();
691  int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
692
693  OS << "Frame Objects:\n";
694
695  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
696    const StackObject &SO = Objects[i];
697    OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
698    if (SO.Size == ~0ULL) {
699      OS << "dead\n";
700      continue;
701    }
702    if (SO.Size == 0)
703      OS << "variable sized";
704    else
705      OS << "size=" << SO.Size;
706    OS << ", align=" << SO.Alignment;
707
708    if (i < NumFixedObjects)
709      OS << ", fixed";
710    if (i < NumFixedObjects || SO.SPOffset != -1) {
711      int64_t Off = SO.SPOffset - ValOffset;
712      OS << ", at location [SP";
713      if (Off > 0)
714        OS << "+" << Off;
715      else if (Off < 0)
716        OS << Off;
717      OS << "]";
718    }
719    OS << "\n";
720  }
721}
722
723#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
724void MachineFrameInfo::dump(const MachineFunction &MF) const {
725  print(MF, dbgs());
726}
727#endif
728
729//===----------------------------------------------------------------------===//
730//  MachineJumpTableInfo implementation
731//===----------------------------------------------------------------------===//
732
733/// Return the size of each entry in the jump table.
734unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
735  // The size of a jump table entry is 4 bytes unless the entry is just the
736  // address of a block, in which case it is the pointer size.
737  switch (getEntryKind()) {
738  case MachineJumpTableInfo::EK_BlockAddress:
739    return TD.getPointerSize();
740  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
741    return 8;
742  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
743  case MachineJumpTableInfo::EK_LabelDifference32:
744  case MachineJumpTableInfo::EK_Custom32:
745    return 4;
746  case MachineJumpTableInfo::EK_Inline:
747    return 0;
748  }
749  llvm_unreachable("Unknown jump table encoding!");
750}
751
752/// Return the alignment of each entry in the jump table.
753unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
754  // The alignment of a jump table entry is the alignment of int32 unless the
755  // entry is just the address of a block, in which case it is the pointer
756  // alignment.
757  switch (getEntryKind()) {
758  case MachineJumpTableInfo::EK_BlockAddress:
759    return TD.getPointerABIAlignment();
760  case MachineJumpTableInfo::EK_GPRel64BlockAddress:
761    return TD.getABIIntegerTypeAlignment(64);
762  case MachineJumpTableInfo::EK_GPRel32BlockAddress:
763  case MachineJumpTableInfo::EK_LabelDifference32:
764  case MachineJumpTableInfo::EK_Custom32:
765    return TD.getABIIntegerTypeAlignment(32);
766  case MachineJumpTableInfo::EK_Inline:
767    return 1;
768  }
769  llvm_unreachable("Unknown jump table encoding!");
770}
771
772/// Create a new jump table entry in the jump table info.
773unsigned MachineJumpTableInfo::createJumpTableIndex(
774                               const std::vector<MachineBasicBlock*> &DestBBs) {
775  assert(!DestBBs.empty() && "Cannot create an empty jump table!");
776  JumpTables.push_back(MachineJumpTableEntry(DestBBs));
777  return JumpTables.size()-1;
778}
779
780/// If Old is the target of any jump tables, update the jump tables to branch
781/// to New instead.
782bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
783                                                  MachineBasicBlock *New) {
784  assert(Old != New && "Not making a change?");
785  bool MadeChange = false;
786  for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
787    ReplaceMBBInJumpTable(i, Old, New);
788  return MadeChange;
789}
790
791/// If Old is a target of the jump tables, update the jump table to branch to
792/// New instead.
793bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
794                                                 MachineBasicBlock *Old,
795                                                 MachineBasicBlock *New) {
796  assert(Old != New && "Not making a change?");
797  bool MadeChange = false;
798  MachineJumpTableEntry &JTE = JumpTables[Idx];
799  for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
800    if (JTE.MBBs[j] == Old) {
801      JTE.MBBs[j] = New;
802      MadeChange = true;
803    }
804  return MadeChange;
805}
806
807void MachineJumpTableInfo::print(raw_ostream &OS) const {
808  if (JumpTables.empty()) return;
809
810  OS << "Jump Tables:\n";
811
812  for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
813    OS << "  jt#" << i << ": ";
814    for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
815      OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
816  }
817
818  OS << '\n';
819}
820
821#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
822void MachineJumpTableInfo::dump() const { print(dbgs()); }
823#endif
824
825
826//===----------------------------------------------------------------------===//
827//  MachineConstantPool implementation
828//===----------------------------------------------------------------------===//
829
830void MachineConstantPoolValue::anchor() { }
831
832Type *MachineConstantPoolEntry::getType() const {
833  if (isMachineConstantPoolEntry())
834    return Val.MachineCPVal->getType();
835  return Val.ConstVal->getType();
836}
837
838bool MachineConstantPoolEntry::needsRelocation() const {
839  if (isMachineConstantPoolEntry())
840    return true;
841  return Val.ConstVal->needsRelocation();
842}
843
844SectionKind
845MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
846  if (needsRelocation())
847    return SectionKind::getReadOnlyWithRel();
848  switch (DL->getTypeAllocSize(getType())) {
849  case 4:
850    return SectionKind::getMergeableConst4();
851  case 8:
852    return SectionKind::getMergeableConst8();
853  case 16:
854    return SectionKind::getMergeableConst16();
855  default:
856    return SectionKind::getReadOnly();
857  }
858}
859
860MachineConstantPool::~MachineConstantPool() {
861  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
862    if (Constants[i].isMachineConstantPoolEntry())
863      delete Constants[i].Val.MachineCPVal;
864  for (DenseSet<MachineConstantPoolValue*>::iterator I =
865       MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
866       I != E; ++I)
867    delete *I;
868}
869
870/// Test whether the given two constants can be allocated the same constant pool
871/// entry.
872static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
873                                      const DataLayout &DL) {
874  // Handle the trivial case quickly.
875  if (A == B) return true;
876
877  // If they have the same type but weren't the same constant, quickly
878  // reject them.
879  if (A->getType() == B->getType()) return false;
880
881  // We can't handle structs or arrays.
882  if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
883      isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
884    return false;
885
886  // For now, only support constants with the same size.
887  uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
888  if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
889    return false;
890
891  Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
892
893  // Try constant folding a bitcast of both instructions to an integer.  If we
894  // get two identical ConstantInt's, then we are good to share them.  We use
895  // the constant folding APIs to do this so that we get the benefit of
896  // DataLayout.
897  if (isa<PointerType>(A->getType()))
898    A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
899                                 const_cast<Constant *>(A), DL);
900  else if (A->getType() != IntTy)
901    A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
902                                 const_cast<Constant *>(A), DL);
903  if (isa<PointerType>(B->getType()))
904    B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
905                                 const_cast<Constant *>(B), DL);
906  else if (B->getType() != IntTy)
907    B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
908                                 const_cast<Constant *>(B), DL);
909
910  return A == B;
911}
912
913/// Create a new entry in the constant pool or return an existing one.
914/// User must specify the log2 of the minimum required alignment for the object.
915unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
916                                                   unsigned Alignment) {
917  assert(Alignment && "Alignment must be specified!");
918  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
919
920  // Check to see if we already have this constant.
921  //
922  // FIXME, this could be made much more efficient for large constant pools.
923  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
924    if (!Constants[i].isMachineConstantPoolEntry() &&
925        CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
926      if ((unsigned)Constants[i].getAlignment() < Alignment)
927        Constants[i].Alignment = Alignment;
928      return i;
929    }
930
931  Constants.push_back(MachineConstantPoolEntry(C, Alignment));
932  return Constants.size()-1;
933}
934
935unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
936                                                   unsigned Alignment) {
937  assert(Alignment && "Alignment must be specified!");
938  if (Alignment > PoolAlignment) PoolAlignment = Alignment;
939
940  // Check to see if we already have this constant.
941  //
942  // FIXME, this could be made much more efficient for large constant pools.
943  int Idx = V->getExistingMachineCPValue(this, Alignment);
944  if (Idx != -1) {
945    MachineCPVsSharingEntries.insert(V);
946    return (unsigned)Idx;
947  }
948
949  Constants.push_back(MachineConstantPoolEntry(V, Alignment));
950  return Constants.size()-1;
951}
952
953void MachineConstantPool::print(raw_ostream &OS) const {
954  if (Constants.empty()) return;
955
956  OS << "Constant Pool:\n";
957  for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
958    OS << "  cp#" << i << ": ";
959    if (Constants[i].isMachineConstantPoolEntry())
960      Constants[i].Val.MachineCPVal->print(OS);
961    else
962      Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
963    OS << ", align=" << Constants[i].getAlignment();
964    OS << "\n";
965  }
966}
967
968#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
969void MachineConstantPool::dump() const { print(dbgs()); }
970#endif
971