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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/CodeGen/MachineConstantPool.h"
21 #include "llvm/CodeGen/MachineFrameInfo.h"
22 #include "llvm/CodeGen/MachineFunctionPass.h"
23 #include "llvm/CodeGen/MachineInstr.h"
24 #include "llvm/CodeGen/MachineJumpTableInfo.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/CodeGen/MachineRegisterInfo.h"
27 #include "llvm/CodeGen/Passes.h"
28 #include "llvm/DebugInfo.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/Function.h"
31 #include "llvm/MC/MCAsmInfo.h"
32 #include "llvm/MC/MCContext.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/GraphWriter.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/Target/TargetFrameLowering.h"
37 #include "llvm/Target/TargetLowering.h"
38 #include "llvm/Target/TargetMachine.h"
39 using namespace llvm;
40 
41 //===----------------------------------------------------------------------===//
42 // MachineFunction implementation
43 //===----------------------------------------------------------------------===//
44 
45 // Out of line virtual method.
~MachineFunctionInfo()46 MachineFunctionInfo::~MachineFunctionInfo() {}
47 
deleteNode(MachineBasicBlock * MBB)48 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
49   MBB->getParent()->DeleteMachineBasicBlock(MBB);
50 }
51 
MachineFunction(const Function * F,const TargetMachine & TM,unsigned FunctionNum,MachineModuleInfo & mmi,GCModuleInfo * gmi)52 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
53                                  unsigned FunctionNum, MachineModuleInfo &mmi,
54                                  GCModuleInfo* gmi)
55   : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
56   if (TM.getRegisterInfo())
57     RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
58   else
59     RegInfo = 0;
60   MFInfo = 0;
61   FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameLowering(),
62                                                TM.Options.RealignStack);
63   if (Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
64                                        Attribute::StackAlignment))
65     FrameInfo->ensureMaxAlignment(Fn->getAttributes().
66                                 getStackAlignment(AttributeSet::FunctionIndex));
67   ConstantPool = new (Allocator) MachineConstantPool(TM.getDataLayout());
68   Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
69   // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
70   if (!Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
71                                         Attribute::OptimizeForSize))
72     Alignment = std::max(Alignment,
73                          TM.getTargetLowering()->getPrefFunctionAlignment());
74   FunctionNumber = FunctionNum;
75   JumpTableInfo = 0;
76 }
77 
~MachineFunction()78 MachineFunction::~MachineFunction() {
79   // Don't call destructors on MachineInstr and MachineOperand. All of their
80   // memory comes from the BumpPtrAllocator which is about to be purged.
81   //
82   // Do call MachineBasicBlock destructors, it contains std::vectors.
83   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
84     I->Insts.clearAndLeakNodesUnsafely();
85 
86   InstructionRecycler.clear(Allocator);
87   OperandRecycler.clear(Allocator);
88   BasicBlockRecycler.clear(Allocator);
89   if (RegInfo) {
90     RegInfo->~MachineRegisterInfo();
91     Allocator.Deallocate(RegInfo);
92   }
93   if (MFInfo) {
94     MFInfo->~MachineFunctionInfo();
95     Allocator.Deallocate(MFInfo);
96   }
97 
98   FrameInfo->~MachineFrameInfo();
99   Allocator.Deallocate(FrameInfo);
100 
101   ConstantPool->~MachineConstantPool();
102   Allocator.Deallocate(ConstantPool);
103 
104   if (JumpTableInfo) {
105     JumpTableInfo->~MachineJumpTableInfo();
106     Allocator.Deallocate(JumpTableInfo);
107   }
108 }
109 
110 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
111 /// does already exist, allocate one.
112 MachineJumpTableInfo *MachineFunction::
getOrCreateJumpTableInfo(unsigned EntryKind)113 getOrCreateJumpTableInfo(unsigned EntryKind) {
114   if (JumpTableInfo) return JumpTableInfo;
115 
116   JumpTableInfo = new (Allocator)
117     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
118   return JumpTableInfo;
119 }
120 
121 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
122 /// recomputes them.  This guarantees that the MBB numbers are sequential,
123 /// dense, and match the ordering of the blocks within the function.  If a
124 /// specific MachineBasicBlock is specified, only that block and those after
125 /// it are renumbered.
RenumberBlocks(MachineBasicBlock * MBB)126 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
127   if (empty()) { MBBNumbering.clear(); return; }
128   MachineFunction::iterator MBBI, E = end();
129   if (MBB == 0)
130     MBBI = begin();
131   else
132     MBBI = MBB;
133 
134   // Figure out the block number this should have.
135   unsigned BlockNo = 0;
136   if (MBBI != begin())
137     BlockNo = prior(MBBI)->getNumber()+1;
138 
139   for (; MBBI != E; ++MBBI, ++BlockNo) {
140     if (MBBI->getNumber() != (int)BlockNo) {
141       // Remove use of the old number.
142       if (MBBI->getNumber() != -1) {
143         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
144                "MBB number mismatch!");
145         MBBNumbering[MBBI->getNumber()] = 0;
146       }
147 
148       // If BlockNo is already taken, set that block's number to -1.
149       if (MBBNumbering[BlockNo])
150         MBBNumbering[BlockNo]->setNumber(-1);
151 
152       MBBNumbering[BlockNo] = MBBI;
153       MBBI->setNumber(BlockNo);
154     }
155   }
156 
157   // Okay, all the blocks are renumbered.  If we have compactified the block
158   // numbering, shrink MBBNumbering now.
159   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
160   MBBNumbering.resize(BlockNo);
161 }
162 
163 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
164 /// of `new MachineInstr'.
165 ///
166 MachineInstr *
CreateMachineInstr(const MCInstrDesc & MCID,DebugLoc DL,bool NoImp)167 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
168                                     DebugLoc DL, bool NoImp) {
169   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
170     MachineInstr(*this, MCID, DL, NoImp);
171 }
172 
173 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
174 /// 'Orig' instruction, identical in all ways except the instruction
175 /// has no parent, prev, or next.
176 ///
177 MachineInstr *
CloneMachineInstr(const MachineInstr * Orig)178 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
179   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
180              MachineInstr(*this, *Orig);
181 }
182 
183 /// DeleteMachineInstr - Delete the given MachineInstr.
184 ///
185 /// This function also serves as the MachineInstr destructor - the real
186 /// ~MachineInstr() destructor must be empty.
187 void
DeleteMachineInstr(MachineInstr * MI)188 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
189   // Strip it for parts. The operand array and the MI object itself are
190   // independently recyclable.
191   if (MI->Operands)
192     deallocateOperandArray(MI->CapOperands, MI->Operands);
193   // Don't call ~MachineInstr() which must be trivial anyway because
194   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
195   // destructors.
196   InstructionRecycler.Deallocate(Allocator, MI);
197 }
198 
199 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
200 /// instead of `new MachineBasicBlock'.
201 ///
202 MachineBasicBlock *
CreateMachineBasicBlock(const BasicBlock * bb)203 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
204   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
205              MachineBasicBlock(*this, bb);
206 }
207 
208 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
209 ///
210 void
DeleteMachineBasicBlock(MachineBasicBlock * MBB)211 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
212   assert(MBB->getParent() == this && "MBB parent mismatch!");
213   MBB->~MachineBasicBlock();
214   BasicBlockRecycler.Deallocate(Allocator, MBB);
215 }
216 
217 MachineMemOperand *
getMachineMemOperand(MachinePointerInfo PtrInfo,unsigned f,uint64_t s,unsigned base_alignment,const MDNode * TBAAInfo,const MDNode * Ranges)218 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
219                                       uint64_t s, unsigned base_alignment,
220                                       const MDNode *TBAAInfo,
221                                       const MDNode *Ranges) {
222   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
223                                            TBAAInfo, Ranges);
224 }
225 
226 MachineMemOperand *
getMachineMemOperand(const MachineMemOperand * MMO,int64_t Offset,uint64_t Size)227 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
228                                       int64_t Offset, uint64_t Size) {
229   return new (Allocator)
230              MachineMemOperand(MachinePointerInfo(MMO->getValue(),
231                                                   MMO->getOffset()+Offset),
232                                MMO->getFlags(), Size,
233                                MMO->getBaseAlignment(), 0);
234 }
235 
236 MachineInstr::mmo_iterator
allocateMemRefsArray(unsigned long Num)237 MachineFunction::allocateMemRefsArray(unsigned long Num) {
238   return Allocator.Allocate<MachineMemOperand *>(Num);
239 }
240 
241 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractLoadMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)242 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
243                                     MachineInstr::mmo_iterator End) {
244   // Count the number of load mem refs.
245   unsigned Num = 0;
246   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
247     if ((*I)->isLoad())
248       ++Num;
249 
250   // Allocate a new array and populate it with the load information.
251   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
252   unsigned Index = 0;
253   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
254     if ((*I)->isLoad()) {
255       if (!(*I)->isStore())
256         // Reuse the MMO.
257         Result[Index] = *I;
258       else {
259         // Clone the MMO and unset the store flag.
260         MachineMemOperand *JustLoad =
261           getMachineMemOperand((*I)->getPointerInfo(),
262                                (*I)->getFlags() & ~MachineMemOperand::MOStore,
263                                (*I)->getSize(), (*I)->getBaseAlignment(),
264                                (*I)->getTBAAInfo());
265         Result[Index] = JustLoad;
266       }
267       ++Index;
268     }
269   }
270   return std::make_pair(Result, Result + Num);
271 }
272 
273 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractStoreMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)274 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
275                                      MachineInstr::mmo_iterator End) {
276   // Count the number of load mem refs.
277   unsigned Num = 0;
278   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
279     if ((*I)->isStore())
280       ++Num;
281 
282   // Allocate a new array and populate it with the store information.
283   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
284   unsigned Index = 0;
285   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
286     if ((*I)->isStore()) {
287       if (!(*I)->isLoad())
288         // Reuse the MMO.
289         Result[Index] = *I;
290       else {
291         // Clone the MMO and unset the load flag.
292         MachineMemOperand *JustStore =
293           getMachineMemOperand((*I)->getPointerInfo(),
294                                (*I)->getFlags() & ~MachineMemOperand::MOLoad,
295                                (*I)->getSize(), (*I)->getBaseAlignment(),
296                                (*I)->getTBAAInfo());
297         Result[Index] = JustStore;
298       }
299       ++Index;
300     }
301   }
302   return std::make_pair(Result, Result + Num);
303 }
304 
305 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const306 void MachineFunction::dump() const {
307   print(dbgs());
308 }
309 #endif
310 
getName() const311 StringRef MachineFunction::getName() const {
312   assert(getFunction() && "No function!");
313   return getFunction()->getName();
314 }
315 
print(raw_ostream & OS,SlotIndexes * Indexes) const316 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
317   OS << "# Machine code for function " << getName() << ": ";
318   if (RegInfo) {
319     OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
320     if (!RegInfo->tracksLiveness())
321       OS << ", not tracking liveness";
322   }
323   OS << '\n';
324 
325   // Print Frame Information
326   FrameInfo->print(*this, OS);
327 
328   // Print JumpTable Information
329   if (JumpTableInfo)
330     JumpTableInfo->print(OS);
331 
332   // Print Constant Pool
333   ConstantPool->print(OS);
334 
335   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
336 
337   if (RegInfo && !RegInfo->livein_empty()) {
338     OS << "Function Live Ins: ";
339     for (MachineRegisterInfo::livein_iterator
340          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
341       OS << PrintReg(I->first, TRI);
342       if (I->second)
343         OS << " in " << PrintReg(I->second, TRI);
344       if (llvm::next(I) != E)
345         OS << ", ";
346     }
347     OS << '\n';
348   }
349 
350   for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
351     OS << '\n';
352     BB->print(OS, Indexes);
353   }
354 
355   OS << "\n# End machine code for function " << getName() << ".\n\n";
356 }
357 
358 namespace llvm {
359   template<>
360   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
361 
DOTGraphTraitsllvm::DOTGraphTraits362   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
363 
getGraphNamellvm::DOTGraphTraits364     static std::string getGraphName(const MachineFunction *F) {
365       return "CFG for '" + F->getName().str() + "' function";
366     }
367 
getNodeLabelllvm::DOTGraphTraits368     std::string getNodeLabel(const MachineBasicBlock *Node,
369                              const MachineFunction *Graph) {
370       std::string OutStr;
371       {
372         raw_string_ostream OSS(OutStr);
373 
374         if (isSimple()) {
375           OSS << "BB#" << Node->getNumber();
376           if (const BasicBlock *BB = Node->getBasicBlock())
377             OSS << ": " << BB->getName();
378         } else
379           Node->print(OSS);
380       }
381 
382       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
383 
384       // Process string output to make it nicer...
385       for (unsigned i = 0; i != OutStr.length(); ++i)
386         if (OutStr[i] == '\n') {                            // Left justify
387           OutStr[i] = '\\';
388           OutStr.insert(OutStr.begin()+i+1, 'l');
389         }
390       return OutStr;
391     }
392   };
393 }
394 
viewCFG() const395 void MachineFunction::viewCFG() const
396 {
397 #ifndef NDEBUG
398   ViewGraph(this, "mf" + getName());
399 #else
400   errs() << "MachineFunction::viewCFG is only available in debug builds on "
401          << "systems with Graphviz or gv!\n";
402 #endif // NDEBUG
403 }
404 
viewCFGOnly() const405 void MachineFunction::viewCFGOnly() const
406 {
407 #ifndef NDEBUG
408   ViewGraph(this, "mf" + getName(), true);
409 #else
410   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
411          << "systems with Graphviz or gv!\n";
412 #endif // NDEBUG
413 }
414 
415 /// addLiveIn - Add the specified physical register as a live-in value and
416 /// create a corresponding virtual register for it.
addLiveIn(unsigned PReg,const TargetRegisterClass * RC)417 unsigned MachineFunction::addLiveIn(unsigned PReg,
418                                     const TargetRegisterClass *RC) {
419   MachineRegisterInfo &MRI = getRegInfo();
420   unsigned VReg = MRI.getLiveInVirtReg(PReg);
421   if (VReg) {
422     assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
423     return VReg;
424   }
425   VReg = MRI.createVirtualRegister(RC);
426   MRI.addLiveIn(PReg, VReg);
427   return VReg;
428 }
429 
430 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
431 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
432 /// normal 'L' label is returned.
getJTISymbol(unsigned JTI,MCContext & Ctx,bool isLinkerPrivate) const433 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
434                                         bool isLinkerPrivate) const {
435   assert(JumpTableInfo && "No jump tables");
436   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
437   const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
438 
439   const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
440                                          MAI.getPrivateGlobalPrefix();
441   SmallString<60> Name;
442   raw_svector_ostream(Name)
443     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
444   return Ctx.GetOrCreateSymbol(Name.str());
445 }
446 
447 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
448 /// base.
getPICBaseSymbol() const449 MCSymbol *MachineFunction::getPICBaseSymbol() const {
450   const MCAsmInfo &MAI = *Target.getMCAsmInfo();
451   return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
452                                Twine(getFunctionNumber())+"$pb");
453 }
454 
455 //===----------------------------------------------------------------------===//
456 //  MachineFrameInfo implementation
457 //===----------------------------------------------------------------------===//
458 
459 /// ensureMaxAlignment - Make sure the function is at least Align bytes
460 /// aligned.
ensureMaxAlignment(unsigned Align)461 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
462   if (!TFI.isStackRealignable() || !RealignOption)
463     assert(Align <= TFI.getStackAlignment() &&
464            "For targets without stack realignment, Align is out of limit!");
465   if (MaxAlignment < Align) MaxAlignment = Align;
466 }
467 
468 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
clampStackAlignment(bool ShouldClamp,unsigned Align,unsigned StackAlign)469 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
470                                            unsigned StackAlign) {
471   if (!ShouldClamp || Align <= StackAlign)
472     return Align;
473   DEBUG(dbgs() << "Warning: requested alignment " << Align
474                << " exceeds the stack alignment " << StackAlign
475                << " when stack realignment is off" << '\n');
476   return StackAlign;
477 }
478 
479 /// CreateStackObject - Create a new statically sized stack object, returning
480 /// a nonnegative identifier to represent it.
481 ///
CreateStackObject(uint64_t Size,unsigned Alignment,bool isSS,bool MayNeedSP,const AllocaInst * Alloca)482 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
483                       bool isSS, bool MayNeedSP, const AllocaInst *Alloca) {
484   assert(Size != 0 && "Cannot allocate zero size stack objects!");
485   Alignment = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
486                                   Alignment, TFI.getStackAlignment());
487   Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, MayNeedSP,
488                                 Alloca));
489   int Index = (int)Objects.size() - NumFixedObjects - 1;
490   assert(Index >= 0 && "Bad frame index!");
491   ensureMaxAlignment(Alignment);
492   return Index;
493 }
494 
495 /// CreateSpillStackObject - Create a new statically sized stack object that
496 /// represents a spill slot, returning a nonnegative identifier to represent
497 /// it.
498 ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)499 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
500                                              unsigned Alignment) {
501   Alignment = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
502                                   Alignment, TFI.getStackAlignment());
503   CreateStackObject(Size, Alignment, true, false);
504   int Index = (int)Objects.size() - NumFixedObjects - 1;
505   ensureMaxAlignment(Alignment);
506   return Index;
507 }
508 
509 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
510 /// variable sized object has been created.  This must be created whenever a
511 /// variable sized object is created, whether or not the index returned is
512 /// actually used.
513 ///
CreateVariableSizedObject(unsigned Alignment)514 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment) {
515   HasVarSizedObjects = true;
516   Alignment = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
517                                   Alignment, TFI.getStackAlignment());
518   Objects.push_back(StackObject(0, Alignment, 0, false, false, true, 0));
519   ensureMaxAlignment(Alignment);
520   return (int)Objects.size()-NumFixedObjects-1;
521 }
522 
523 /// CreateFixedObject - Create a new object at a fixed location on the stack.
524 /// All fixed objects should be created before other objects are created for
525 /// efficiency. By default, fixed objects are immutable. This returns an
526 /// index with a negative value.
527 ///
CreateFixedObject(uint64_t Size,int64_t SPOffset,bool Immutable)528 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
529                                         bool Immutable) {
530   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
531   // The alignment of the frame index can be determined from its offset from
532   // the incoming frame position.  If the frame object is at offset 32 and
533   // the stack is guaranteed to be 16-byte aligned, then we know that the
534   // object is 16-byte aligned.
535   unsigned StackAlign = TFI.getStackAlignment();
536   unsigned Align = MinAlign(SPOffset, StackAlign);
537   Align = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
538                               Align, TFI.getStackAlignment());
539   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
540                                               /*isSS*/   false,
541                                               /*NeedSP*/ false,
542                                               /*Alloca*/ 0));
543   return -++NumFixedObjects;
544 }
545 
546 
547 BitVector
getPristineRegs(const MachineBasicBlock * MBB) const548 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
549   assert(MBB && "MBB must be valid");
550   const MachineFunction *MF = MBB->getParent();
551   assert(MF && "MBB must be part of a MachineFunction");
552   const TargetMachine &TM = MF->getTarget();
553   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
554   BitVector BV(TRI->getNumRegs());
555 
556   // Before CSI is calculated, no registers are considered pristine. They can be
557   // freely used and PEI will make sure they are saved.
558   if (!isCalleeSavedInfoValid())
559     return BV;
560 
561   for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
562     BV.set(*CSR);
563 
564   // The entry MBB always has all CSRs pristine.
565   if (MBB == &MF->front())
566     return BV;
567 
568   // On other MBBs the saved CSRs are not pristine.
569   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
570   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
571          E = CSI.end(); I != E; ++I)
572     BV.reset(I->getReg());
573 
574   return BV;
575 }
576 
estimateStackSize(const MachineFunction & MF) const577 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
578   const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
579   const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
580   unsigned MaxAlign = getMaxAlignment();
581   int Offset = 0;
582 
583   // This code is very, very similar to PEI::calculateFrameObjectOffsets().
584   // It really should be refactored to share code. Until then, changes
585   // should keep in mind that there's tight coupling between the two.
586 
587   for (int i = getObjectIndexBegin(); i != 0; ++i) {
588     int FixedOff = -getObjectOffset(i);
589     if (FixedOff > Offset) Offset = FixedOff;
590   }
591   for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
592     if (isDeadObjectIndex(i))
593       continue;
594     Offset += getObjectSize(i);
595     unsigned Align = getObjectAlignment(i);
596     // Adjust to alignment boundary
597     Offset = (Offset+Align-1)/Align*Align;
598 
599     MaxAlign = std::max(Align, MaxAlign);
600   }
601 
602   if (adjustsStack() && TFI->hasReservedCallFrame(MF))
603     Offset += getMaxCallFrameSize();
604 
605   // Round up the size to a multiple of the alignment.  If the function has
606   // any calls or alloca's, align to the target's StackAlignment value to
607   // ensure that the callee's frame or the alloca data is suitably aligned;
608   // otherwise, for leaf functions, align to the TransientStackAlignment
609   // value.
610   unsigned StackAlign;
611   if (adjustsStack() || hasVarSizedObjects() ||
612       (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
613     StackAlign = TFI->getStackAlignment();
614   else
615     StackAlign = TFI->getTransientStackAlignment();
616 
617   // If the frame pointer is eliminated, all frame offsets will be relative to
618   // SP not FP. Align to MaxAlign so this works.
619   StackAlign = std::max(StackAlign, MaxAlign);
620   unsigned AlignMask = StackAlign - 1;
621   Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
622 
623   return (unsigned)Offset;
624 }
625 
print(const MachineFunction & MF,raw_ostream & OS) const626 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
627   if (Objects.empty()) return;
628 
629   const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
630   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
631 
632   OS << "Frame Objects:\n";
633 
634   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
635     const StackObject &SO = Objects[i];
636     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
637     if (SO.Size == ~0ULL) {
638       OS << "dead\n";
639       continue;
640     }
641     if (SO.Size == 0)
642       OS << "variable sized";
643     else
644       OS << "size=" << SO.Size;
645     OS << ", align=" << SO.Alignment;
646 
647     if (i < NumFixedObjects)
648       OS << ", fixed";
649     if (i < NumFixedObjects || SO.SPOffset != -1) {
650       int64_t Off = SO.SPOffset - ValOffset;
651       OS << ", at location [SP";
652       if (Off > 0)
653         OS << "+" << Off;
654       else if (Off < 0)
655         OS << Off;
656       OS << "]";
657     }
658     OS << "\n";
659   }
660 }
661 
662 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump(const MachineFunction & MF) const663 void MachineFrameInfo::dump(const MachineFunction &MF) const {
664   print(MF, dbgs());
665 }
666 #endif
667 
668 //===----------------------------------------------------------------------===//
669 //  MachineJumpTableInfo implementation
670 //===----------------------------------------------------------------------===//
671 
672 /// getEntrySize - Return the size of each entry in the jump table.
getEntrySize(const DataLayout & TD) const673 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
674   // The size of a jump table entry is 4 bytes unless the entry is just the
675   // address of a block, in which case it is the pointer size.
676   switch (getEntryKind()) {
677   case MachineJumpTableInfo::EK_BlockAddress:
678     return TD.getPointerSize();
679   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
680     return 8;
681   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
682   case MachineJumpTableInfo::EK_LabelDifference32:
683   case MachineJumpTableInfo::EK_Custom32:
684     return 4;
685   case MachineJumpTableInfo::EK_Inline:
686     return 0;
687   }
688   llvm_unreachable("Unknown jump table encoding!");
689 }
690 
691 /// getEntryAlignment - Return the alignment of each entry in the jump table.
getEntryAlignment(const DataLayout & TD) const692 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
693   // The alignment of a jump table entry is the alignment of int32 unless the
694   // entry is just the address of a block, in which case it is the pointer
695   // alignment.
696   switch (getEntryKind()) {
697   case MachineJumpTableInfo::EK_BlockAddress:
698     return TD.getPointerABIAlignment();
699   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
700     return TD.getABIIntegerTypeAlignment(64);
701   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
702   case MachineJumpTableInfo::EK_LabelDifference32:
703   case MachineJumpTableInfo::EK_Custom32:
704     return TD.getABIIntegerTypeAlignment(32);
705   case MachineJumpTableInfo::EK_Inline:
706     return 1;
707   }
708   llvm_unreachable("Unknown jump table encoding!");
709 }
710 
711 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
712 ///
createJumpTableIndex(const std::vector<MachineBasicBlock * > & DestBBs)713 unsigned MachineJumpTableInfo::createJumpTableIndex(
714                                const std::vector<MachineBasicBlock*> &DestBBs) {
715   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
716   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
717   return JumpTables.size()-1;
718 }
719 
720 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
721 /// the jump tables to branch to New instead.
ReplaceMBBInJumpTables(MachineBasicBlock * Old,MachineBasicBlock * New)722 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
723                                                   MachineBasicBlock *New) {
724   assert(Old != New && "Not making a change?");
725   bool MadeChange = false;
726   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
727     ReplaceMBBInJumpTable(i, Old, New);
728   return MadeChange;
729 }
730 
731 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
732 /// the jump table to branch to New instead.
ReplaceMBBInJumpTable(unsigned Idx,MachineBasicBlock * Old,MachineBasicBlock * New)733 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
734                                                  MachineBasicBlock *Old,
735                                                  MachineBasicBlock *New) {
736   assert(Old != New && "Not making a change?");
737   bool MadeChange = false;
738   MachineJumpTableEntry &JTE = JumpTables[Idx];
739   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
740     if (JTE.MBBs[j] == Old) {
741       JTE.MBBs[j] = New;
742       MadeChange = true;
743     }
744   return MadeChange;
745 }
746 
print(raw_ostream & OS) const747 void MachineJumpTableInfo::print(raw_ostream &OS) const {
748   if (JumpTables.empty()) return;
749 
750   OS << "Jump Tables:\n";
751 
752   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
753     OS << "  jt#" << i << ": ";
754     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
755       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
756   }
757 
758   OS << '\n';
759 }
760 
761 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const762 void MachineJumpTableInfo::dump() const { print(dbgs()); }
763 #endif
764 
765 
766 //===----------------------------------------------------------------------===//
767 //  MachineConstantPool implementation
768 //===----------------------------------------------------------------------===//
769 
anchor()770 void MachineConstantPoolValue::anchor() { }
771 
getType() const772 Type *MachineConstantPoolEntry::getType() const {
773   if (isMachineConstantPoolEntry())
774     return Val.MachineCPVal->getType();
775   return Val.ConstVal->getType();
776 }
777 
778 
getRelocationInfo() const779 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
780   if (isMachineConstantPoolEntry())
781     return Val.MachineCPVal->getRelocationInfo();
782   return Val.ConstVal->getRelocationInfo();
783 }
784 
~MachineConstantPool()785 MachineConstantPool::~MachineConstantPool() {
786   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
787     if (Constants[i].isMachineConstantPoolEntry())
788       delete Constants[i].Val.MachineCPVal;
789   for (DenseSet<MachineConstantPoolValue*>::iterator I =
790        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
791        I != E; ++I)
792     delete *I;
793 }
794 
795 /// CanShareConstantPoolEntry - Test whether the given two constants
796 /// can be allocated the same constant pool entry.
CanShareConstantPoolEntry(const Constant * A,const Constant * B,const DataLayout * TD)797 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
798                                       const DataLayout *TD) {
799   // Handle the trivial case quickly.
800   if (A == B) return true;
801 
802   // If they have the same type but weren't the same constant, quickly
803   // reject them.
804   if (A->getType() == B->getType()) return false;
805 
806   // We can't handle structs or arrays.
807   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
808       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
809     return false;
810 
811   // For now, only support constants with the same size.
812   uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
813   if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
814       StoreSize > 128)
815     return false;
816 
817   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
818 
819   // Try constant folding a bitcast of both instructions to an integer.  If we
820   // get two identical ConstantInt's, then we are good to share them.  We use
821   // the constant folding APIs to do this so that we get the benefit of
822   // DataLayout.
823   if (isa<PointerType>(A->getType()))
824     A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
825                                  const_cast<Constant*>(A), TD);
826   else if (A->getType() != IntTy)
827     A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
828                                  const_cast<Constant*>(A), TD);
829   if (isa<PointerType>(B->getType()))
830     B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
831                                  const_cast<Constant*>(B), TD);
832   else if (B->getType() != IntTy)
833     B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
834                                  const_cast<Constant*>(B), TD);
835 
836   return A == B;
837 }
838 
839 /// getConstantPoolIndex - Create a new entry in the constant pool or return
840 /// an existing one.  User must specify the log2 of the minimum required
841 /// alignment for the object.
842 ///
getConstantPoolIndex(const Constant * C,unsigned Alignment)843 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
844                                                    unsigned Alignment) {
845   assert(Alignment && "Alignment must be specified!");
846   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
847 
848   // Check to see if we already have this constant.
849   //
850   // FIXME, this could be made much more efficient for large constant pools.
851   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
852     if (!Constants[i].isMachineConstantPoolEntry() &&
853         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
854       if ((unsigned)Constants[i].getAlignment() < Alignment)
855         Constants[i].Alignment = Alignment;
856       return i;
857     }
858 
859   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
860   return Constants.size()-1;
861 }
862 
getConstantPoolIndex(MachineConstantPoolValue * V,unsigned Alignment)863 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
864                                                    unsigned Alignment) {
865   assert(Alignment && "Alignment must be specified!");
866   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
867 
868   // Check to see if we already have this constant.
869   //
870   // FIXME, this could be made much more efficient for large constant pools.
871   int Idx = V->getExistingMachineCPValue(this, Alignment);
872   if (Idx != -1) {
873     MachineCPVsSharingEntries.insert(V);
874     return (unsigned)Idx;
875   }
876 
877   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
878   return Constants.size()-1;
879 }
880 
print(raw_ostream & OS) const881 void MachineConstantPool::print(raw_ostream &OS) const {
882   if (Constants.empty()) return;
883 
884   OS << "Constant Pool:\n";
885   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
886     OS << "  cp#" << i << ": ";
887     if (Constants[i].isMachineConstantPoolEntry())
888       Constants[i].Val.MachineCPVal->print(OS);
889     else
890       OS << *(const Value*)Constants[i].Val.ConstVal;
891     OS << ", align=" << Constants[i].getAlignment();
892     OS << "\n";
893   }
894 }
895 
896 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const897 void MachineConstantPool::dump() const { print(dbgs()); }
898 #endif
899