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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/Assembly/Writer.h"
21 #include "llvm/CodeGen/MachineConstantPool.h"
22 #include "llvm/CodeGen/MachineFrameInfo.h"
23 #include "llvm/CodeGen/MachineFunctionPass.h"
24 #include "llvm/CodeGen/MachineInstr.h"
25 #include "llvm/CodeGen/MachineJumpTableInfo.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/CodeGen/MachineRegisterInfo.h"
28 #include "llvm/CodeGen/Passes.h"
29 #include "llvm/DebugInfo.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/Function.h"
32 #include "llvm/MC/MCAsmInfo.h"
33 #include "llvm/MC/MCContext.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/GraphWriter.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include "llvm/Target/TargetFrameLowering.h"
38 #include "llvm/Target/TargetLowering.h"
39 #include "llvm/Target/TargetMachine.h"
40 using namespace llvm;
41 
42 //===----------------------------------------------------------------------===//
43 // MachineFunction implementation
44 //===----------------------------------------------------------------------===//
45 
46 // Out of line virtual method.
~MachineFunctionInfo()47 MachineFunctionInfo::~MachineFunctionInfo() {}
48 
deleteNode(MachineBasicBlock * MBB)49 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
50   MBB->getParent()->DeleteMachineBasicBlock(MBB);
51 }
52 
MachineFunction(const Function * F,const TargetMachine & TM,unsigned FunctionNum,MachineModuleInfo & mmi,GCModuleInfo * gmi)53 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
54                                  unsigned FunctionNum, MachineModuleInfo &mmi,
55                                  GCModuleInfo* gmi)
56   : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
57   if (TM.getRegisterInfo())
58     RegInfo = new (Allocator) MachineRegisterInfo(TM);
59   else
60     RegInfo = 0;
61 
62   MFInfo = 0;
63   FrameInfo =
64     new (Allocator) MachineFrameInfo(TM,!F->hasFnAttribute("no-realign-stack"));
65 
66   if (Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
67                                        Attribute::StackAlignment))
68     FrameInfo->ensureMaxAlignment(Fn->getAttributes().
69                                 getStackAlignment(AttributeSet::FunctionIndex));
70 
71   ConstantPool = new (Allocator) MachineConstantPool(TM);
72   Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
73 
74   // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
75   if (!Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
76                                         Attribute::OptimizeForSize))
77     Alignment = std::max(Alignment,
78                          TM.getTargetLowering()->getPrefFunctionAlignment());
79 
80   FunctionNumber = FunctionNum;
81   JumpTableInfo = 0;
82 }
83 
~MachineFunction()84 MachineFunction::~MachineFunction() {
85   // Don't call destructors on MachineInstr and MachineOperand. All of their
86   // memory comes from the BumpPtrAllocator which is about to be purged.
87   //
88   // Do call MachineBasicBlock destructors, it contains std::vectors.
89   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
90     I->Insts.clearAndLeakNodesUnsafely();
91 
92   InstructionRecycler.clear(Allocator);
93   OperandRecycler.clear(Allocator);
94   BasicBlockRecycler.clear(Allocator);
95   if (RegInfo) {
96     RegInfo->~MachineRegisterInfo();
97     Allocator.Deallocate(RegInfo);
98   }
99   if (MFInfo) {
100     MFInfo->~MachineFunctionInfo();
101     Allocator.Deallocate(MFInfo);
102   }
103 
104   FrameInfo->~MachineFrameInfo();
105   Allocator.Deallocate(FrameInfo);
106 
107   ConstantPool->~MachineConstantPool();
108   Allocator.Deallocate(ConstantPool);
109 
110   if (JumpTableInfo) {
111     JumpTableInfo->~MachineJumpTableInfo();
112     Allocator.Deallocate(JumpTableInfo);
113   }
114 }
115 
116 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
117 /// does already exist, allocate one.
118 MachineJumpTableInfo *MachineFunction::
getOrCreateJumpTableInfo(unsigned EntryKind)119 getOrCreateJumpTableInfo(unsigned EntryKind) {
120   if (JumpTableInfo) return JumpTableInfo;
121 
122   JumpTableInfo = new (Allocator)
123     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
124   return JumpTableInfo;
125 }
126 
127 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
128 /// recomputes them.  This guarantees that the MBB numbers are sequential,
129 /// dense, and match the ordering of the blocks within the function.  If a
130 /// specific MachineBasicBlock is specified, only that block and those after
131 /// it are renumbered.
RenumberBlocks(MachineBasicBlock * MBB)132 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
133   if (empty()) { MBBNumbering.clear(); return; }
134   MachineFunction::iterator MBBI, E = end();
135   if (MBB == 0)
136     MBBI = begin();
137   else
138     MBBI = MBB;
139 
140   // Figure out the block number this should have.
141   unsigned BlockNo = 0;
142   if (MBBI != begin())
143     BlockNo = prior(MBBI)->getNumber()+1;
144 
145   for (; MBBI != E; ++MBBI, ++BlockNo) {
146     if (MBBI->getNumber() != (int)BlockNo) {
147       // Remove use of the old number.
148       if (MBBI->getNumber() != -1) {
149         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
150                "MBB number mismatch!");
151         MBBNumbering[MBBI->getNumber()] = 0;
152       }
153 
154       // If BlockNo is already taken, set that block's number to -1.
155       if (MBBNumbering[BlockNo])
156         MBBNumbering[BlockNo]->setNumber(-1);
157 
158       MBBNumbering[BlockNo] = MBBI;
159       MBBI->setNumber(BlockNo);
160     }
161   }
162 
163   // Okay, all the blocks are renumbered.  If we have compactified the block
164   // numbering, shrink MBBNumbering now.
165   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
166   MBBNumbering.resize(BlockNo);
167 }
168 
169 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
170 /// of `new MachineInstr'.
171 ///
172 MachineInstr *
CreateMachineInstr(const MCInstrDesc & MCID,DebugLoc DL,bool NoImp)173 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
174                                     DebugLoc DL, bool NoImp) {
175   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
176     MachineInstr(*this, MCID, DL, NoImp);
177 }
178 
179 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
180 /// 'Orig' instruction, identical in all ways except the instruction
181 /// has no parent, prev, or next.
182 ///
183 MachineInstr *
CloneMachineInstr(const MachineInstr * Orig)184 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
185   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
186              MachineInstr(*this, *Orig);
187 }
188 
189 /// DeleteMachineInstr - Delete the given MachineInstr.
190 ///
191 /// This function also serves as the MachineInstr destructor - the real
192 /// ~MachineInstr() destructor must be empty.
193 void
DeleteMachineInstr(MachineInstr * MI)194 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
195   // Strip it for parts. The operand array and the MI object itself are
196   // independently recyclable.
197   if (MI->Operands)
198     deallocateOperandArray(MI->CapOperands, MI->Operands);
199   // Don't call ~MachineInstr() which must be trivial anyway because
200   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
201   // destructors.
202   InstructionRecycler.Deallocate(Allocator, MI);
203 }
204 
205 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
206 /// instead of `new MachineBasicBlock'.
207 ///
208 MachineBasicBlock *
CreateMachineBasicBlock(const BasicBlock * bb)209 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
210   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
211              MachineBasicBlock(*this, bb);
212 }
213 
214 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
215 ///
216 void
DeleteMachineBasicBlock(MachineBasicBlock * MBB)217 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
218   assert(MBB->getParent() == this && "MBB parent mismatch!");
219   MBB->~MachineBasicBlock();
220   BasicBlockRecycler.Deallocate(Allocator, MBB);
221 }
222 
223 MachineMemOperand *
getMachineMemOperand(MachinePointerInfo PtrInfo,unsigned f,uint64_t s,unsigned base_alignment,const MDNode * TBAAInfo,const MDNode * Ranges)224 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
225                                       uint64_t s, unsigned base_alignment,
226                                       const MDNode *TBAAInfo,
227                                       const MDNode *Ranges) {
228   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
229                                            TBAAInfo, Ranges);
230 }
231 
232 MachineMemOperand *
getMachineMemOperand(const MachineMemOperand * MMO,int64_t Offset,uint64_t Size)233 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
234                                       int64_t Offset, uint64_t Size) {
235   return new (Allocator)
236              MachineMemOperand(MachinePointerInfo(MMO->getValue(),
237                                                   MMO->getOffset()+Offset),
238                                MMO->getFlags(), Size,
239                                MMO->getBaseAlignment(), 0);
240 }
241 
242 MachineInstr::mmo_iterator
allocateMemRefsArray(unsigned long Num)243 MachineFunction::allocateMemRefsArray(unsigned long Num) {
244   return Allocator.Allocate<MachineMemOperand *>(Num);
245 }
246 
247 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractLoadMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)248 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
249                                     MachineInstr::mmo_iterator End) {
250   // Count the number of load mem refs.
251   unsigned Num = 0;
252   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
253     if ((*I)->isLoad())
254       ++Num;
255 
256   // Allocate a new array and populate it with the load information.
257   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
258   unsigned Index = 0;
259   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
260     if ((*I)->isLoad()) {
261       if (!(*I)->isStore())
262         // Reuse the MMO.
263         Result[Index] = *I;
264       else {
265         // Clone the MMO and unset the store flag.
266         MachineMemOperand *JustLoad =
267           getMachineMemOperand((*I)->getPointerInfo(),
268                                (*I)->getFlags() & ~MachineMemOperand::MOStore,
269                                (*I)->getSize(), (*I)->getBaseAlignment(),
270                                (*I)->getTBAAInfo());
271         Result[Index] = JustLoad;
272       }
273       ++Index;
274     }
275   }
276   return std::make_pair(Result, Result + Num);
277 }
278 
279 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractStoreMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)280 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
281                                      MachineInstr::mmo_iterator End) {
282   // Count the number of load mem refs.
283   unsigned Num = 0;
284   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
285     if ((*I)->isStore())
286       ++Num;
287 
288   // Allocate a new array and populate it with the store information.
289   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
290   unsigned Index = 0;
291   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
292     if ((*I)->isStore()) {
293       if (!(*I)->isLoad())
294         // Reuse the MMO.
295         Result[Index] = *I;
296       else {
297         // Clone the MMO and unset the load flag.
298         MachineMemOperand *JustStore =
299           getMachineMemOperand((*I)->getPointerInfo(),
300                                (*I)->getFlags() & ~MachineMemOperand::MOLoad,
301                                (*I)->getSize(), (*I)->getBaseAlignment(),
302                                (*I)->getTBAAInfo());
303         Result[Index] = JustStore;
304       }
305       ++Index;
306     }
307   }
308   return std::make_pair(Result, Result + Num);
309 }
310 
311 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const312 void MachineFunction::dump() const {
313   print(dbgs());
314 }
315 #endif
316 
getName() const317 StringRef MachineFunction::getName() const {
318   assert(getFunction() && "No function!");
319   return getFunction()->getName();
320 }
321 
print(raw_ostream & OS,SlotIndexes * Indexes) const322 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
323   OS << "# Machine code for function " << getName() << ": ";
324   if (RegInfo) {
325     OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
326     if (!RegInfo->tracksLiveness())
327       OS << ", not tracking liveness";
328   }
329   OS << '\n';
330 
331   // Print Frame Information
332   FrameInfo->print(*this, OS);
333 
334   // Print JumpTable Information
335   if (JumpTableInfo)
336     JumpTableInfo->print(OS);
337 
338   // Print Constant Pool
339   ConstantPool->print(OS);
340 
341   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
342 
343   if (RegInfo && !RegInfo->livein_empty()) {
344     OS << "Function Live Ins: ";
345     for (MachineRegisterInfo::livein_iterator
346          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
347       OS << PrintReg(I->first, TRI);
348       if (I->second)
349         OS << " in " << PrintReg(I->second, TRI);
350       if (llvm::next(I) != E)
351         OS << ", ";
352     }
353     OS << '\n';
354   }
355 
356   for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
357     OS << '\n';
358     BB->print(OS, Indexes);
359   }
360 
361   OS << "\n# End machine code for function " << getName() << ".\n\n";
362 }
363 
364 namespace llvm {
365   template<>
366   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
367 
DOTGraphTraitsllvm::DOTGraphTraits368   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
369 
getGraphNamellvm::DOTGraphTraits370     static std::string getGraphName(const MachineFunction *F) {
371       return "CFG for '" + F->getName().str() + "' function";
372     }
373 
getNodeLabelllvm::DOTGraphTraits374     std::string getNodeLabel(const MachineBasicBlock *Node,
375                              const MachineFunction *Graph) {
376       std::string OutStr;
377       {
378         raw_string_ostream OSS(OutStr);
379 
380         if (isSimple()) {
381           OSS << "BB#" << Node->getNumber();
382           if (const BasicBlock *BB = Node->getBasicBlock())
383             OSS << ": " << BB->getName();
384         } else
385           Node->print(OSS);
386       }
387 
388       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
389 
390       // Process string output to make it nicer...
391       for (unsigned i = 0; i != OutStr.length(); ++i)
392         if (OutStr[i] == '\n') {                            // Left justify
393           OutStr[i] = '\\';
394           OutStr.insert(OutStr.begin()+i+1, 'l');
395         }
396       return OutStr;
397     }
398   };
399 }
400 
viewCFG() const401 void MachineFunction::viewCFG() const
402 {
403 #ifndef NDEBUG
404   ViewGraph(this, "mf" + getName());
405 #else
406   errs() << "MachineFunction::viewCFG is only available in debug builds on "
407          << "systems with Graphviz or gv!\n";
408 #endif // NDEBUG
409 }
410 
viewCFGOnly() const411 void MachineFunction::viewCFGOnly() const
412 {
413 #ifndef NDEBUG
414   ViewGraph(this, "mf" + getName(), true);
415 #else
416   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
417          << "systems with Graphviz or gv!\n";
418 #endif // NDEBUG
419 }
420 
421 /// addLiveIn - Add the specified physical register as a live-in value and
422 /// create a corresponding virtual register for it.
addLiveIn(unsigned PReg,const TargetRegisterClass * RC)423 unsigned MachineFunction::addLiveIn(unsigned PReg,
424                                     const TargetRegisterClass *RC) {
425   MachineRegisterInfo &MRI = getRegInfo();
426   unsigned VReg = MRI.getLiveInVirtReg(PReg);
427   if (VReg) {
428     assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
429     return VReg;
430   }
431   VReg = MRI.createVirtualRegister(RC);
432   MRI.addLiveIn(PReg, VReg);
433   return VReg;
434 }
435 
436 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
437 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
438 /// normal 'L' label is returned.
getJTISymbol(unsigned JTI,MCContext & Ctx,bool isLinkerPrivate) const439 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
440                                         bool isLinkerPrivate) const {
441   assert(JumpTableInfo && "No jump tables");
442   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
443   const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
444 
445   const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
446                                          MAI.getPrivateGlobalPrefix();
447   SmallString<60> Name;
448   raw_svector_ostream(Name)
449     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
450   return Ctx.GetOrCreateSymbol(Name.str());
451 }
452 
453 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
454 /// base.
getPICBaseSymbol() const455 MCSymbol *MachineFunction::getPICBaseSymbol() const {
456   const MCAsmInfo &MAI = *Target.getMCAsmInfo();
457   return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
458                                Twine(getFunctionNumber())+"$pb");
459 }
460 
461 //===----------------------------------------------------------------------===//
462 //  MachineFrameInfo implementation
463 //===----------------------------------------------------------------------===//
464 
getFrameLowering() const465 const TargetFrameLowering *MachineFrameInfo::getFrameLowering() const {
466   return TM.getFrameLowering();
467 }
468 
469 /// ensureMaxAlignment - Make sure the function is at least Align bytes
470 /// aligned.
ensureMaxAlignment(unsigned Align)471 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
472   if (!getFrameLowering()->isStackRealignable() || !RealignOption)
473     assert(Align <= getFrameLowering()->getStackAlignment() &&
474            "For targets without stack realignment, Align is out of limit!");
475   if (MaxAlignment < Align) MaxAlignment = Align;
476 }
477 
478 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
clampStackAlignment(bool ShouldClamp,unsigned Align,unsigned StackAlign)479 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
480                                            unsigned StackAlign) {
481   if (!ShouldClamp || Align <= StackAlign)
482     return Align;
483   DEBUG(dbgs() << "Warning: requested alignment " << Align
484                << " exceeds the stack alignment " << StackAlign
485                << " when stack realignment is off" << '\n');
486   return StackAlign;
487 }
488 
489 /// CreateStackObject - Create a new statically sized stack object, returning
490 /// a nonnegative identifier to represent it.
491 ///
CreateStackObject(uint64_t Size,unsigned Alignment,bool isSS,bool MayNeedSP,const AllocaInst * Alloca)492 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
493                       bool isSS, bool MayNeedSP, const AllocaInst *Alloca) {
494   assert(Size != 0 && "Cannot allocate zero size stack objects!");
495   Alignment =
496     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
497                           !RealignOption,
498                         Alignment, getFrameLowering()->getStackAlignment());
499   Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, MayNeedSP,
500                                 Alloca));
501   int Index = (int)Objects.size() - NumFixedObjects - 1;
502   assert(Index >= 0 && "Bad frame index!");
503   ensureMaxAlignment(Alignment);
504   return Index;
505 }
506 
507 /// CreateSpillStackObject - Create a new statically sized stack object that
508 /// represents a spill slot, returning a nonnegative identifier to represent
509 /// it.
510 ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)511 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
512                                              unsigned Alignment) {
513   Alignment =
514     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
515                           !RealignOption,
516                         Alignment, getFrameLowering()->getStackAlignment());
517   CreateStackObject(Size, Alignment, true, false);
518   int Index = (int)Objects.size() - NumFixedObjects - 1;
519   ensureMaxAlignment(Alignment);
520   return Index;
521 }
522 
523 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
524 /// variable sized object has been created.  This must be created whenever a
525 /// variable sized object is created, whether or not the index returned is
526 /// actually used.
527 ///
CreateVariableSizedObject(unsigned Alignment)528 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment) {
529   HasVarSizedObjects = true;
530   Alignment =
531     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
532                           !RealignOption,
533                         Alignment, getFrameLowering()->getStackAlignment());
534   Objects.push_back(StackObject(0, Alignment, 0, false, false, true, 0));
535   ensureMaxAlignment(Alignment);
536   return (int)Objects.size()-NumFixedObjects-1;
537 }
538 
539 /// CreateFixedObject - Create a new object at a fixed location on the stack.
540 /// All fixed objects should be created before other objects are created for
541 /// efficiency. By default, fixed objects are immutable. This returns an
542 /// index with a negative value.
543 ///
CreateFixedObject(uint64_t Size,int64_t SPOffset,bool Immutable)544 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
545                                         bool Immutable) {
546   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
547   // The alignment of the frame index can be determined from its offset from
548   // the incoming frame position.  If the frame object is at offset 32 and
549   // the stack is guaranteed to be 16-byte aligned, then we know that the
550   // object is 16-byte aligned.
551   unsigned StackAlign = getFrameLowering()->getStackAlignment();
552   unsigned Align = MinAlign(SPOffset, StackAlign);
553   Align =
554     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
555                           !RealignOption,
556                         Align, getFrameLowering()->getStackAlignment());
557   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
558                                               /*isSS*/   false,
559                                               /*NeedSP*/ false,
560                                               /*Alloca*/ 0));
561   return -++NumFixedObjects;
562 }
563 
564 
565 BitVector
getPristineRegs(const MachineBasicBlock * MBB) const566 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
567   assert(MBB && "MBB must be valid");
568   const MachineFunction *MF = MBB->getParent();
569   assert(MF && "MBB must be part of a MachineFunction");
570   const TargetMachine &TM = MF->getTarget();
571   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
572   BitVector BV(TRI->getNumRegs());
573 
574   // Before CSI is calculated, no registers are considered pristine. They can be
575   // freely used and PEI will make sure they are saved.
576   if (!isCalleeSavedInfoValid())
577     return BV;
578 
579   for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
580     BV.set(*CSR);
581 
582   // The entry MBB always has all CSRs pristine.
583   if (MBB == &MF->front())
584     return BV;
585 
586   // On other MBBs the saved CSRs are not pristine.
587   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
588   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
589          E = CSI.end(); I != E; ++I)
590     BV.reset(I->getReg());
591 
592   return BV;
593 }
594 
estimateStackSize(const MachineFunction & MF) const595 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
596   const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
597   const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
598   unsigned MaxAlign = getMaxAlignment();
599   int Offset = 0;
600 
601   // This code is very, very similar to PEI::calculateFrameObjectOffsets().
602   // It really should be refactored to share code. Until then, changes
603   // should keep in mind that there's tight coupling between the two.
604 
605   for (int i = getObjectIndexBegin(); i != 0; ++i) {
606     int FixedOff = -getObjectOffset(i);
607     if (FixedOff > Offset) Offset = FixedOff;
608   }
609   for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
610     if (isDeadObjectIndex(i))
611       continue;
612     Offset += getObjectSize(i);
613     unsigned Align = getObjectAlignment(i);
614     // Adjust to alignment boundary
615     Offset = (Offset+Align-1)/Align*Align;
616 
617     MaxAlign = std::max(Align, MaxAlign);
618   }
619 
620   if (adjustsStack() && TFI->hasReservedCallFrame(MF))
621     Offset += getMaxCallFrameSize();
622 
623   // Round up the size to a multiple of the alignment.  If the function has
624   // any calls or alloca's, align to the target's StackAlignment value to
625   // ensure that the callee's frame or the alloca data is suitably aligned;
626   // otherwise, for leaf functions, align to the TransientStackAlignment
627   // value.
628   unsigned StackAlign;
629   if (adjustsStack() || hasVarSizedObjects() ||
630       (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
631     StackAlign = TFI->getStackAlignment();
632   else
633     StackAlign = TFI->getTransientStackAlignment();
634 
635   // If the frame pointer is eliminated, all frame offsets will be relative to
636   // SP not FP. Align to MaxAlign so this works.
637   StackAlign = std::max(StackAlign, MaxAlign);
638   unsigned AlignMask = StackAlign - 1;
639   Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
640 
641   return (unsigned)Offset;
642 }
643 
print(const MachineFunction & MF,raw_ostream & OS) const644 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
645   if (Objects.empty()) return;
646 
647   const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
648   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
649 
650   OS << "Frame Objects:\n";
651 
652   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
653     const StackObject &SO = Objects[i];
654     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
655     if (SO.Size == ~0ULL) {
656       OS << "dead\n";
657       continue;
658     }
659     if (SO.Size == 0)
660       OS << "variable sized";
661     else
662       OS << "size=" << SO.Size;
663     OS << ", align=" << SO.Alignment;
664 
665     if (i < NumFixedObjects)
666       OS << ", fixed";
667     if (i < NumFixedObjects || SO.SPOffset != -1) {
668       int64_t Off = SO.SPOffset - ValOffset;
669       OS << ", at location [SP";
670       if (Off > 0)
671         OS << "+" << Off;
672       else if (Off < 0)
673         OS << Off;
674       OS << "]";
675     }
676     OS << "\n";
677   }
678 }
679 
680 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump(const MachineFunction & MF) const681 void MachineFrameInfo::dump(const MachineFunction &MF) const {
682   print(MF, dbgs());
683 }
684 #endif
685 
686 //===----------------------------------------------------------------------===//
687 //  MachineJumpTableInfo implementation
688 //===----------------------------------------------------------------------===//
689 
690 /// getEntrySize - Return the size of each entry in the jump table.
getEntrySize(const DataLayout & TD) const691 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
692   // The size of a jump table entry is 4 bytes unless the entry is just the
693   // address of a block, in which case it is the pointer size.
694   switch (getEntryKind()) {
695   case MachineJumpTableInfo::EK_BlockAddress:
696     return TD.getPointerSize();
697   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
698     return 8;
699   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
700   case MachineJumpTableInfo::EK_LabelDifference32:
701   case MachineJumpTableInfo::EK_Custom32:
702     return 4;
703   case MachineJumpTableInfo::EK_Inline:
704     return 0;
705   }
706   llvm_unreachable("Unknown jump table encoding!");
707 }
708 
709 /// getEntryAlignment - Return the alignment of each entry in the jump table.
getEntryAlignment(const DataLayout & TD) const710 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
711   // The alignment of a jump table entry is the alignment of int32 unless the
712   // entry is just the address of a block, in which case it is the pointer
713   // alignment.
714   switch (getEntryKind()) {
715   case MachineJumpTableInfo::EK_BlockAddress:
716     return TD.getPointerABIAlignment();
717   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
718     return TD.getABIIntegerTypeAlignment(64);
719   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
720   case MachineJumpTableInfo::EK_LabelDifference32:
721   case MachineJumpTableInfo::EK_Custom32:
722     return TD.getABIIntegerTypeAlignment(32);
723   case MachineJumpTableInfo::EK_Inline:
724     return 1;
725   }
726   llvm_unreachable("Unknown jump table encoding!");
727 }
728 
729 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
730 ///
createJumpTableIndex(const std::vector<MachineBasicBlock * > & DestBBs)731 unsigned MachineJumpTableInfo::createJumpTableIndex(
732                                const std::vector<MachineBasicBlock*> &DestBBs) {
733   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
734   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
735   return JumpTables.size()-1;
736 }
737 
738 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
739 /// the jump tables to branch to New instead.
ReplaceMBBInJumpTables(MachineBasicBlock * Old,MachineBasicBlock * New)740 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
741                                                   MachineBasicBlock *New) {
742   assert(Old != New && "Not making a change?");
743   bool MadeChange = false;
744   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
745     ReplaceMBBInJumpTable(i, Old, New);
746   return MadeChange;
747 }
748 
749 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
750 /// the jump table to branch to New instead.
ReplaceMBBInJumpTable(unsigned Idx,MachineBasicBlock * Old,MachineBasicBlock * New)751 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
752                                                  MachineBasicBlock *Old,
753                                                  MachineBasicBlock *New) {
754   assert(Old != New && "Not making a change?");
755   bool MadeChange = false;
756   MachineJumpTableEntry &JTE = JumpTables[Idx];
757   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
758     if (JTE.MBBs[j] == Old) {
759       JTE.MBBs[j] = New;
760       MadeChange = true;
761     }
762   return MadeChange;
763 }
764 
print(raw_ostream & OS) const765 void MachineJumpTableInfo::print(raw_ostream &OS) const {
766   if (JumpTables.empty()) return;
767 
768   OS << "Jump Tables:\n";
769 
770   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
771     OS << "  jt#" << i << ": ";
772     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
773       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
774   }
775 
776   OS << '\n';
777 }
778 
779 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const780 void MachineJumpTableInfo::dump() const { print(dbgs()); }
781 #endif
782 
783 
784 //===----------------------------------------------------------------------===//
785 //  MachineConstantPool implementation
786 //===----------------------------------------------------------------------===//
787 
anchor()788 void MachineConstantPoolValue::anchor() { }
789 
getDataLayout() const790 const DataLayout *MachineConstantPool::getDataLayout() const {
791   return TM.getDataLayout();
792 }
793 
getType() const794 Type *MachineConstantPoolEntry::getType() const {
795   if (isMachineConstantPoolEntry())
796     return Val.MachineCPVal->getType();
797   return Val.ConstVal->getType();
798 }
799 
800 
getRelocationInfo() const801 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
802   if (isMachineConstantPoolEntry())
803     return Val.MachineCPVal->getRelocationInfo();
804   return Val.ConstVal->getRelocationInfo();
805 }
806 
~MachineConstantPool()807 MachineConstantPool::~MachineConstantPool() {
808   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
809     if (Constants[i].isMachineConstantPoolEntry())
810       delete Constants[i].Val.MachineCPVal;
811   for (DenseSet<MachineConstantPoolValue*>::iterator I =
812        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
813        I != E; ++I)
814     delete *I;
815 }
816 
817 /// CanShareConstantPoolEntry - Test whether the given two constants
818 /// can be allocated the same constant pool entry.
CanShareConstantPoolEntry(const Constant * A,const Constant * B,const DataLayout * TD)819 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
820                                       const DataLayout *TD) {
821   // Handle the trivial case quickly.
822   if (A == B) return true;
823 
824   // If they have the same type but weren't the same constant, quickly
825   // reject them.
826   if (A->getType() == B->getType()) return false;
827 
828   // We can't handle structs or arrays.
829   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
830       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
831     return false;
832 
833   // For now, only support constants with the same size.
834   uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
835   if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
836       StoreSize > 128)
837     return false;
838 
839   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
840 
841   // Try constant folding a bitcast of both instructions to an integer.  If we
842   // get two identical ConstantInt's, then we are good to share them.  We use
843   // the constant folding APIs to do this so that we get the benefit of
844   // DataLayout.
845   if (isa<PointerType>(A->getType()))
846     A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
847                                  const_cast<Constant*>(A), TD);
848   else if (A->getType() != IntTy)
849     A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
850                                  const_cast<Constant*>(A), TD);
851   if (isa<PointerType>(B->getType()))
852     B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
853                                  const_cast<Constant*>(B), TD);
854   else if (B->getType() != IntTy)
855     B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
856                                  const_cast<Constant*>(B), TD);
857 
858   return A == B;
859 }
860 
861 /// getConstantPoolIndex - Create a new entry in the constant pool or return
862 /// an existing one.  User must specify the log2 of the minimum required
863 /// alignment for the object.
864 ///
getConstantPoolIndex(const Constant * C,unsigned Alignment)865 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
866                                                    unsigned Alignment) {
867   assert(Alignment && "Alignment must be specified!");
868   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
869 
870   // Check to see if we already have this constant.
871   //
872   // FIXME, this could be made much more efficient for large constant pools.
873   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
874     if (!Constants[i].isMachineConstantPoolEntry() &&
875         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C,
876                                   getDataLayout())) {
877       if ((unsigned)Constants[i].getAlignment() < Alignment)
878         Constants[i].Alignment = Alignment;
879       return i;
880     }
881 
882   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
883   return Constants.size()-1;
884 }
885 
getConstantPoolIndex(MachineConstantPoolValue * V,unsigned Alignment)886 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
887                                                    unsigned Alignment) {
888   assert(Alignment && "Alignment must be specified!");
889   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
890 
891   // Check to see if we already have this constant.
892   //
893   // FIXME, this could be made much more efficient for large constant pools.
894   int Idx = V->getExistingMachineCPValue(this, Alignment);
895   if (Idx != -1) {
896     MachineCPVsSharingEntries.insert(V);
897     return (unsigned)Idx;
898   }
899 
900   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
901   return Constants.size()-1;
902 }
903 
print(raw_ostream & OS) const904 void MachineConstantPool::print(raw_ostream &OS) const {
905   if (Constants.empty()) return;
906 
907   OS << "Constant Pool:\n";
908   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
909     OS << "  cp#" << i << ": ";
910     if (Constants[i].isMachineConstantPoolEntry())
911       Constants[i].Val.MachineCPVal->print(OS);
912     else
913       WriteAsOperand(OS, Constants[i].Val.ConstVal, /*PrintType=*/false);
914     OS << ", align=" << Constants[i].getAlignment();
915     OS << "\n";
916   }
917 }
918 
919 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const920 void MachineConstantPool::dump() const { print(dbgs()); }
921 #endif
922