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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/IR/DataLayout.h"
29 #include "llvm/IR/DebugInfo.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 #define DEBUG_TYPE "codegen"
42 
43 //===----------------------------------------------------------------------===//
44 // MachineFunction implementation
45 //===----------------------------------------------------------------------===//
46 
47 // Out of line virtual method.
~MachineFunctionInfo()48 MachineFunctionInfo::~MachineFunctionInfo() {}
49 
deleteNode(MachineBasicBlock * MBB)50 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
51   MBB->getParent()->DeleteMachineBasicBlock(MBB);
52 }
53 
MachineFunction(const Function * F,const TargetMachine & TM,unsigned FunctionNum,MachineModuleInfo & mmi,GCModuleInfo * gmi)54 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
55                                  unsigned FunctionNum, MachineModuleInfo &mmi,
56                                  GCModuleInfo* gmi)
57   : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
58   if (TM.getRegisterInfo())
59     RegInfo = new (Allocator) MachineRegisterInfo(TM);
60   else
61     RegInfo = nullptr;
62 
63   MFInfo = nullptr;
64   FrameInfo =
65     new (Allocator) MachineFrameInfo(TM,!F->hasFnAttribute("no-realign-stack"));
66 
67   if (Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
68                                        Attribute::StackAlignment))
69     FrameInfo->ensureMaxAlignment(Fn->getAttributes().
70                                 getStackAlignment(AttributeSet::FunctionIndex));
71 
72   ConstantPool = new (Allocator) MachineConstantPool(TM);
73   Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
74 
75   // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
76   if (!Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
77                                         Attribute::OptimizeForSize))
78     Alignment = std::max(Alignment,
79                          TM.getTargetLowering()->getPrefFunctionAlignment());
80 
81   FunctionNumber = FunctionNum;
82   JumpTableInfo = nullptr;
83 }
84 
~MachineFunction()85 MachineFunction::~MachineFunction() {
86   // Don't call destructors on MachineInstr and MachineOperand. All of their
87   // memory comes from the BumpPtrAllocator which is about to be purged.
88   //
89   // Do call MachineBasicBlock destructors, it contains std::vectors.
90   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
91     I->Insts.clearAndLeakNodesUnsafely();
92 
93   InstructionRecycler.clear(Allocator);
94   OperandRecycler.clear(Allocator);
95   BasicBlockRecycler.clear(Allocator);
96   if (RegInfo) {
97     RegInfo->~MachineRegisterInfo();
98     Allocator.Deallocate(RegInfo);
99   }
100   if (MFInfo) {
101     MFInfo->~MachineFunctionInfo();
102     Allocator.Deallocate(MFInfo);
103   }
104 
105   FrameInfo->~MachineFrameInfo();
106   Allocator.Deallocate(FrameInfo);
107 
108   ConstantPool->~MachineConstantPool();
109   Allocator.Deallocate(ConstantPool);
110 
111   if (JumpTableInfo) {
112     JumpTableInfo->~MachineJumpTableInfo();
113     Allocator.Deallocate(JumpTableInfo);
114   }
115 }
116 
117 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
118 /// does already exist, allocate one.
119 MachineJumpTableInfo *MachineFunction::
getOrCreateJumpTableInfo(unsigned EntryKind)120 getOrCreateJumpTableInfo(unsigned EntryKind) {
121   if (JumpTableInfo) return JumpTableInfo;
122 
123   JumpTableInfo = new (Allocator)
124     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
125   return JumpTableInfo;
126 }
127 
128 /// Should we be emitting segmented stack stuff for the function
shouldSplitStack()129 bool MachineFunction::shouldSplitStack() {
130   return getFunction()->hasFnAttribute("split-stack");
131 }
132 
133 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
134 /// recomputes them.  This guarantees that the MBB numbers are sequential,
135 /// dense, and match the ordering of the blocks within the function.  If a
136 /// specific MachineBasicBlock is specified, only that block and those after
137 /// it are renumbered.
RenumberBlocks(MachineBasicBlock * MBB)138 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
139   if (empty()) { MBBNumbering.clear(); return; }
140   MachineFunction::iterator MBBI, E = end();
141   if (MBB == nullptr)
142     MBBI = begin();
143   else
144     MBBI = MBB;
145 
146   // Figure out the block number this should have.
147   unsigned BlockNo = 0;
148   if (MBBI != begin())
149     BlockNo = std::prev(MBBI)->getNumber() + 1;
150 
151   for (; MBBI != E; ++MBBI, ++BlockNo) {
152     if (MBBI->getNumber() != (int)BlockNo) {
153       // Remove use of the old number.
154       if (MBBI->getNumber() != -1) {
155         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
156                "MBB number mismatch!");
157         MBBNumbering[MBBI->getNumber()] = nullptr;
158       }
159 
160       // If BlockNo is already taken, set that block's number to -1.
161       if (MBBNumbering[BlockNo])
162         MBBNumbering[BlockNo]->setNumber(-1);
163 
164       MBBNumbering[BlockNo] = MBBI;
165       MBBI->setNumber(BlockNo);
166     }
167   }
168 
169   // Okay, all the blocks are renumbered.  If we have compactified the block
170   // numbering, shrink MBBNumbering now.
171   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
172   MBBNumbering.resize(BlockNo);
173 }
174 
175 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
176 /// of `new MachineInstr'.
177 ///
178 MachineInstr *
CreateMachineInstr(const MCInstrDesc & MCID,DebugLoc DL,bool NoImp)179 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
180                                     DebugLoc DL, bool NoImp) {
181   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
182     MachineInstr(*this, MCID, DL, NoImp);
183 }
184 
185 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
186 /// 'Orig' instruction, identical in all ways except the instruction
187 /// has no parent, prev, or next.
188 ///
189 MachineInstr *
CloneMachineInstr(const MachineInstr * Orig)190 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
191   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
192              MachineInstr(*this, *Orig);
193 }
194 
195 /// DeleteMachineInstr - Delete the given MachineInstr.
196 ///
197 /// This function also serves as the MachineInstr destructor - the real
198 /// ~MachineInstr() destructor must be empty.
199 void
DeleteMachineInstr(MachineInstr * MI)200 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
201   // Strip it for parts. The operand array and the MI object itself are
202   // independently recyclable.
203   if (MI->Operands)
204     deallocateOperandArray(MI->CapOperands, MI->Operands);
205   // Don't call ~MachineInstr() which must be trivial anyway because
206   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
207   // destructors.
208   InstructionRecycler.Deallocate(Allocator, MI);
209 }
210 
211 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
212 /// instead of `new MachineBasicBlock'.
213 ///
214 MachineBasicBlock *
CreateMachineBasicBlock(const BasicBlock * bb)215 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
216   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
217              MachineBasicBlock(*this, bb);
218 }
219 
220 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
221 ///
222 void
DeleteMachineBasicBlock(MachineBasicBlock * MBB)223 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
224   assert(MBB->getParent() == this && "MBB parent mismatch!");
225   MBB->~MachineBasicBlock();
226   BasicBlockRecycler.Deallocate(Allocator, MBB);
227 }
228 
229 MachineMemOperand *
getMachineMemOperand(MachinePointerInfo PtrInfo,unsigned f,uint64_t s,unsigned base_alignment,const MDNode * TBAAInfo,const MDNode * Ranges)230 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
231                                       uint64_t s, unsigned base_alignment,
232                                       const MDNode *TBAAInfo,
233                                       const MDNode *Ranges) {
234   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
235                                            TBAAInfo, Ranges);
236 }
237 
238 MachineMemOperand *
getMachineMemOperand(const MachineMemOperand * MMO,int64_t Offset,uint64_t Size)239 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
240                                       int64_t Offset, uint64_t Size) {
241   if (MMO->getValue())
242     return new (Allocator)
243                MachineMemOperand(MachinePointerInfo(MMO->getValue(),
244                                                     MMO->getOffset()+Offset),
245                                  MMO->getFlags(), Size,
246                                  MMO->getBaseAlignment(), nullptr);
247   return new (Allocator)
248              MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(),
249                                                   MMO->getOffset()+Offset),
250                                MMO->getFlags(), Size,
251                                MMO->getBaseAlignment(), nullptr);
252 }
253 
254 MachineInstr::mmo_iterator
allocateMemRefsArray(unsigned long Num)255 MachineFunction::allocateMemRefsArray(unsigned long Num) {
256   return Allocator.Allocate<MachineMemOperand *>(Num);
257 }
258 
259 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractLoadMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)260 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
261                                     MachineInstr::mmo_iterator End) {
262   // Count the number of load mem refs.
263   unsigned Num = 0;
264   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
265     if ((*I)->isLoad())
266       ++Num;
267 
268   // Allocate a new array and populate it with the load information.
269   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
270   unsigned Index = 0;
271   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
272     if ((*I)->isLoad()) {
273       if (!(*I)->isStore())
274         // Reuse the MMO.
275         Result[Index] = *I;
276       else {
277         // Clone the MMO and unset the store flag.
278         MachineMemOperand *JustLoad =
279           getMachineMemOperand((*I)->getPointerInfo(),
280                                (*I)->getFlags() & ~MachineMemOperand::MOStore,
281                                (*I)->getSize(), (*I)->getBaseAlignment(),
282                                (*I)->getTBAAInfo());
283         Result[Index] = JustLoad;
284       }
285       ++Index;
286     }
287   }
288   return std::make_pair(Result, Result + Num);
289 }
290 
291 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractStoreMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)292 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
293                                      MachineInstr::mmo_iterator End) {
294   // Count the number of load mem refs.
295   unsigned Num = 0;
296   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
297     if ((*I)->isStore())
298       ++Num;
299 
300   // Allocate a new array and populate it with the store information.
301   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
302   unsigned Index = 0;
303   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
304     if ((*I)->isStore()) {
305       if (!(*I)->isLoad())
306         // Reuse the MMO.
307         Result[Index] = *I;
308       else {
309         // Clone the MMO and unset the load flag.
310         MachineMemOperand *JustStore =
311           getMachineMemOperand((*I)->getPointerInfo(),
312                                (*I)->getFlags() & ~MachineMemOperand::MOLoad,
313                                (*I)->getSize(), (*I)->getBaseAlignment(),
314                                (*I)->getTBAAInfo());
315         Result[Index] = JustStore;
316       }
317       ++Index;
318     }
319   }
320   return std::make_pair(Result, Result + Num);
321 }
322 
323 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const324 void MachineFunction::dump() const {
325   print(dbgs());
326 }
327 #endif
328 
getName() const329 StringRef MachineFunction::getName() const {
330   assert(getFunction() && "No function!");
331   return getFunction()->getName();
332 }
333 
print(raw_ostream & OS,SlotIndexes * Indexes) const334 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
335   OS << "# Machine code for function " << getName() << ": ";
336   if (RegInfo) {
337     OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
338     if (!RegInfo->tracksLiveness())
339       OS << ", not tracking liveness";
340   }
341   OS << '\n';
342 
343   // Print Frame Information
344   FrameInfo->print(*this, OS);
345 
346   // Print JumpTable Information
347   if (JumpTableInfo)
348     JumpTableInfo->print(OS);
349 
350   // Print Constant Pool
351   ConstantPool->print(OS);
352 
353   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
354 
355   if (RegInfo && !RegInfo->livein_empty()) {
356     OS << "Function Live Ins: ";
357     for (MachineRegisterInfo::livein_iterator
358          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
359       OS << PrintReg(I->first, TRI);
360       if (I->second)
361         OS << " in " << PrintReg(I->second, TRI);
362       if (std::next(I) != E)
363         OS << ", ";
364     }
365     OS << '\n';
366   }
367 
368   for (const auto &BB : *this) {
369     OS << '\n';
370     BB.print(OS, Indexes);
371   }
372 
373   OS << "\n# End machine code for function " << getName() << ".\n\n";
374 }
375 
376 namespace llvm {
377   template<>
378   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
379 
DOTGraphTraitsllvm::DOTGraphTraits380   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
381 
getGraphNamellvm::DOTGraphTraits382     static std::string getGraphName(const MachineFunction *F) {
383       return "CFG for '" + F->getName().str() + "' function";
384     }
385 
getNodeLabelllvm::DOTGraphTraits386     std::string getNodeLabel(const MachineBasicBlock *Node,
387                              const MachineFunction *Graph) {
388       std::string OutStr;
389       {
390         raw_string_ostream OSS(OutStr);
391 
392         if (isSimple()) {
393           OSS << "BB#" << Node->getNumber();
394           if (const BasicBlock *BB = Node->getBasicBlock())
395             OSS << ": " << BB->getName();
396         } else
397           Node->print(OSS);
398       }
399 
400       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
401 
402       // Process string output to make it nicer...
403       for (unsigned i = 0; i != OutStr.length(); ++i)
404         if (OutStr[i] == '\n') {                            // Left justify
405           OutStr[i] = '\\';
406           OutStr.insert(OutStr.begin()+i+1, 'l');
407         }
408       return OutStr;
409     }
410   };
411 }
412 
viewCFG() const413 void MachineFunction::viewCFG() const
414 {
415 #ifndef NDEBUG
416   ViewGraph(this, "mf" + getName());
417 #else
418   errs() << "MachineFunction::viewCFG is only available in debug builds on "
419          << "systems with Graphviz or gv!\n";
420 #endif // NDEBUG
421 }
422 
viewCFGOnly() const423 void MachineFunction::viewCFGOnly() const
424 {
425 #ifndef NDEBUG
426   ViewGraph(this, "mf" + getName(), true);
427 #else
428   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
429          << "systems with Graphviz or gv!\n";
430 #endif // NDEBUG
431 }
432 
433 /// addLiveIn - Add the specified physical register as a live-in value and
434 /// create a corresponding virtual register for it.
addLiveIn(unsigned PReg,const TargetRegisterClass * RC)435 unsigned MachineFunction::addLiveIn(unsigned PReg,
436                                     const TargetRegisterClass *RC) {
437   MachineRegisterInfo &MRI = getRegInfo();
438   unsigned VReg = MRI.getLiveInVirtReg(PReg);
439   if (VReg) {
440     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
441     (void)VRegRC;
442     // A physical register can be added several times.
443     // Between two calls, the register class of the related virtual register
444     // may have been constrained to match some operation constraints.
445     // In that case, check that the current register class includes the
446     // physical register and is a sub class of the specified RC.
447     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
448                              RC->hasSubClassEq(VRegRC))) &&
449             "Register class mismatch!");
450     return VReg;
451   }
452   VReg = MRI.createVirtualRegister(RC);
453   MRI.addLiveIn(PReg, VReg);
454   return VReg;
455 }
456 
457 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
458 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
459 /// normal 'L' label is returned.
getJTISymbol(unsigned JTI,MCContext & Ctx,bool isLinkerPrivate) const460 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
461                                         bool isLinkerPrivate) const {
462   const DataLayout *DL = getTarget().getDataLayout();
463   assert(JumpTableInfo && "No jump tables");
464   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
465 
466   const char *Prefix = isLinkerPrivate ? DL->getLinkerPrivateGlobalPrefix() :
467                                          DL->getPrivateGlobalPrefix();
468   SmallString<60> Name;
469   raw_svector_ostream(Name)
470     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
471   return Ctx.GetOrCreateSymbol(Name.str());
472 }
473 
474 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
475 /// base.
getPICBaseSymbol() const476 MCSymbol *MachineFunction::getPICBaseSymbol() const {
477   const DataLayout *DL = getTarget().getDataLayout();
478   return Ctx.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix())+
479                                Twine(getFunctionNumber())+"$pb");
480 }
481 
482 //===----------------------------------------------------------------------===//
483 //  MachineFrameInfo implementation
484 //===----------------------------------------------------------------------===//
485 
getFrameLowering() const486 const TargetFrameLowering *MachineFrameInfo::getFrameLowering() const {
487   return TM.getFrameLowering();
488 }
489 
490 /// ensureMaxAlignment - Make sure the function is at least Align bytes
491 /// aligned.
ensureMaxAlignment(unsigned Align)492 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
493   if (!getFrameLowering()->isStackRealignable() || !RealignOption)
494     assert(Align <= getFrameLowering()->getStackAlignment() &&
495            "For targets without stack realignment, Align is out of limit!");
496   if (MaxAlignment < Align) MaxAlignment = Align;
497 }
498 
499 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
clampStackAlignment(bool ShouldClamp,unsigned Align,unsigned StackAlign)500 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
501                                            unsigned StackAlign) {
502   if (!ShouldClamp || Align <= StackAlign)
503     return Align;
504   DEBUG(dbgs() << "Warning: requested alignment " << Align
505                << " exceeds the stack alignment " << StackAlign
506                << " when stack realignment is off" << '\n');
507   return StackAlign;
508 }
509 
510 /// CreateStackObject - Create a new statically sized stack object, returning
511 /// a nonnegative identifier to represent it.
512 ///
CreateStackObject(uint64_t Size,unsigned Alignment,bool isSS,const AllocaInst * Alloca)513 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
514                       bool isSS, const AllocaInst *Alloca) {
515   assert(Size != 0 && "Cannot allocate zero size stack objects!");
516   Alignment =
517     clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
518                           !RealignOption,
519                         Alignment, getFrameLowering()->getStackAlignment());
520   Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, Alloca));
521   int Index = (int)Objects.size() - NumFixedObjects - 1;
522   assert(Index >= 0 && "Bad frame index!");
523   ensureMaxAlignment(Alignment);
524   return Index;
525 }
526 
527 /// CreateSpillStackObject - Create a new statically sized stack object that
528 /// represents a spill slot, returning a nonnegative identifier to represent
529 /// it.
530 ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)531 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
532                                              unsigned Alignment) {
533   Alignment = clampStackAlignment(
534       !getFrameLowering()->isStackRealignable() || !RealignOption, Alignment,
535       getFrameLowering()->getStackAlignment());
536   CreateStackObject(Size, Alignment, true);
537   int Index = (int)Objects.size() - NumFixedObjects - 1;
538   ensureMaxAlignment(Alignment);
539   return Index;
540 }
541 
542 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
543 /// variable sized object has been created.  This must be created whenever a
544 /// variable sized object is created, whether or not the index returned is
545 /// actually used.
546 ///
CreateVariableSizedObject(unsigned Alignment,const AllocaInst * Alloca)547 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment,
548                                                 const AllocaInst *Alloca) {
549   HasVarSizedObjects = true;
550   Alignment = clampStackAlignment(
551       !getFrameLowering()->isStackRealignable() || !RealignOption, Alignment,
552       getFrameLowering()->getStackAlignment());
553   Objects.push_back(StackObject(0, Alignment, 0, false, false, Alloca));
554   ensureMaxAlignment(Alignment);
555   return (int)Objects.size()-NumFixedObjects-1;
556 }
557 
558 /// CreateFixedObject - Create a new object at a fixed location on the stack.
559 /// All fixed objects should be created before other objects are created for
560 /// efficiency. By default, fixed objects are immutable. This returns an
561 /// index with a negative value.
562 ///
CreateFixedObject(uint64_t Size,int64_t SPOffset,bool Immutable)563 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
564                                         bool Immutable) {
565   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
566   // The alignment of the frame index can be determined from its offset from
567   // the incoming frame position.  If the frame object is at offset 32 and
568   // the stack is guaranteed to be 16-byte aligned, then we know that the
569   // object is 16-byte aligned.
570   unsigned StackAlign = getFrameLowering()->getStackAlignment();
571   unsigned Align = MinAlign(SPOffset, StackAlign);
572   Align = clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
573                                   !RealignOption,
574                               Align, getFrameLowering()->getStackAlignment());
575   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
576                                               /*isSS*/   false,
577                                               /*Alloca*/ nullptr));
578   return -++NumFixedObjects;
579 }
580 
581 /// CreateFixedSpillStackObject - Create a spill slot at a fixed location
582 /// on the stack.  Returns an index with a negative value.
CreateFixedSpillStackObject(uint64_t Size,int64_t SPOffset)583 int MachineFrameInfo::CreateFixedSpillStackObject(uint64_t Size,
584                                                   int64_t SPOffset) {
585   unsigned StackAlign = getFrameLowering()->getStackAlignment();
586   unsigned Align = MinAlign(SPOffset, StackAlign);
587   Align = clampStackAlignment(!getFrameLowering()->isStackRealignable() ||
588                                   !RealignOption,
589                               Align, getFrameLowering()->getStackAlignment());
590   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset,
591                                               /*Immutable*/ true,
592                                               /*isSS*/ true,
593                                               /*Alloca*/ nullptr));
594   return -++NumFixedObjects;
595 }
596 
597 BitVector
getPristineRegs(const MachineBasicBlock * MBB) const598 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
599   assert(MBB && "MBB must be valid");
600   const MachineFunction *MF = MBB->getParent();
601   assert(MF && "MBB must be part of a MachineFunction");
602   const TargetMachine &TM = MF->getTarget();
603   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
604   BitVector BV(TRI->getNumRegs());
605 
606   // Before CSI is calculated, no registers are considered pristine. They can be
607   // freely used and PEI will make sure they are saved.
608   if (!isCalleeSavedInfoValid())
609     return BV;
610 
611   for (const MCPhysReg *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
612     BV.set(*CSR);
613 
614   // The entry MBB always has all CSRs pristine.
615   if (MBB == &MF->front())
616     return BV;
617 
618   // On other MBBs the saved CSRs are not pristine.
619   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
620   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
621          E = CSI.end(); I != E; ++I)
622     BV.reset(I->getReg());
623 
624   return BV;
625 }
626 
estimateStackSize(const MachineFunction & MF) const627 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
628   const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
629   const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
630   unsigned MaxAlign = getMaxAlignment();
631   int Offset = 0;
632 
633   // This code is very, very similar to PEI::calculateFrameObjectOffsets().
634   // It really should be refactored to share code. Until then, changes
635   // should keep in mind that there's tight coupling between the two.
636 
637   for (int i = getObjectIndexBegin(); i != 0; ++i) {
638     int FixedOff = -getObjectOffset(i);
639     if (FixedOff > Offset) Offset = FixedOff;
640   }
641   for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
642     if (isDeadObjectIndex(i))
643       continue;
644     Offset += getObjectSize(i);
645     unsigned Align = getObjectAlignment(i);
646     // Adjust to alignment boundary
647     Offset = (Offset+Align-1)/Align*Align;
648 
649     MaxAlign = std::max(Align, MaxAlign);
650   }
651 
652   if (adjustsStack() && TFI->hasReservedCallFrame(MF))
653     Offset += getMaxCallFrameSize();
654 
655   // Round up the size to a multiple of the alignment.  If the function has
656   // any calls or alloca's, align to the target's StackAlignment value to
657   // ensure that the callee's frame or the alloca data is suitably aligned;
658   // otherwise, for leaf functions, align to the TransientStackAlignment
659   // value.
660   unsigned StackAlign;
661   if (adjustsStack() || hasVarSizedObjects() ||
662       (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
663     StackAlign = TFI->getStackAlignment();
664   else
665     StackAlign = TFI->getTransientStackAlignment();
666 
667   // If the frame pointer is eliminated, all frame offsets will be relative to
668   // SP not FP. Align to MaxAlign so this works.
669   StackAlign = std::max(StackAlign, MaxAlign);
670   unsigned AlignMask = StackAlign - 1;
671   Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
672 
673   return (unsigned)Offset;
674 }
675 
print(const MachineFunction & MF,raw_ostream & OS) const676 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
677   if (Objects.empty()) return;
678 
679   const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
680   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
681 
682   OS << "Frame Objects:\n";
683 
684   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
685     const StackObject &SO = Objects[i];
686     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
687     if (SO.Size == ~0ULL) {
688       OS << "dead\n";
689       continue;
690     }
691     if (SO.Size == 0)
692       OS << "variable sized";
693     else
694       OS << "size=" << SO.Size;
695     OS << ", align=" << SO.Alignment;
696 
697     if (i < NumFixedObjects)
698       OS << ", fixed";
699     if (i < NumFixedObjects || SO.SPOffset != -1) {
700       int64_t Off = SO.SPOffset - ValOffset;
701       OS << ", at location [SP";
702       if (Off > 0)
703         OS << "+" << Off;
704       else if (Off < 0)
705         OS << Off;
706       OS << "]";
707     }
708     OS << "\n";
709   }
710 }
711 
712 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump(const MachineFunction & MF) const713 void MachineFrameInfo::dump(const MachineFunction &MF) const {
714   print(MF, dbgs());
715 }
716 #endif
717 
718 //===----------------------------------------------------------------------===//
719 //  MachineJumpTableInfo implementation
720 //===----------------------------------------------------------------------===//
721 
722 /// getEntrySize - Return the size of each entry in the jump table.
getEntrySize(const DataLayout & TD) const723 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
724   // The size of a jump table entry is 4 bytes unless the entry is just the
725   // address of a block, in which case it is the pointer size.
726   switch (getEntryKind()) {
727   case MachineJumpTableInfo::EK_BlockAddress:
728     return TD.getPointerSize();
729   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
730     return 8;
731   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
732   case MachineJumpTableInfo::EK_LabelDifference32:
733   case MachineJumpTableInfo::EK_Custom32:
734     return 4;
735   case MachineJumpTableInfo::EK_Inline:
736     return 0;
737   }
738   llvm_unreachable("Unknown jump table encoding!");
739 }
740 
741 /// getEntryAlignment - Return the alignment of each entry in the jump table.
getEntryAlignment(const DataLayout & TD) const742 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
743   // The alignment of a jump table entry is the alignment of int32 unless the
744   // entry is just the address of a block, in which case it is the pointer
745   // alignment.
746   switch (getEntryKind()) {
747   case MachineJumpTableInfo::EK_BlockAddress:
748     return TD.getPointerABIAlignment();
749   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
750     return TD.getABIIntegerTypeAlignment(64);
751   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
752   case MachineJumpTableInfo::EK_LabelDifference32:
753   case MachineJumpTableInfo::EK_Custom32:
754     return TD.getABIIntegerTypeAlignment(32);
755   case MachineJumpTableInfo::EK_Inline:
756     return 1;
757   }
758   llvm_unreachable("Unknown jump table encoding!");
759 }
760 
761 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
762 ///
createJumpTableIndex(const std::vector<MachineBasicBlock * > & DestBBs)763 unsigned MachineJumpTableInfo::createJumpTableIndex(
764                                const std::vector<MachineBasicBlock*> &DestBBs) {
765   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
766   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
767   return JumpTables.size()-1;
768 }
769 
770 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
771 /// the jump tables to branch to New instead.
ReplaceMBBInJumpTables(MachineBasicBlock * Old,MachineBasicBlock * New)772 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
773                                                   MachineBasicBlock *New) {
774   assert(Old != New && "Not making a change?");
775   bool MadeChange = false;
776   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
777     ReplaceMBBInJumpTable(i, Old, New);
778   return MadeChange;
779 }
780 
781 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
782 /// the jump table to branch to New instead.
ReplaceMBBInJumpTable(unsigned Idx,MachineBasicBlock * Old,MachineBasicBlock * New)783 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
784                                                  MachineBasicBlock *Old,
785                                                  MachineBasicBlock *New) {
786   assert(Old != New && "Not making a change?");
787   bool MadeChange = false;
788   MachineJumpTableEntry &JTE = JumpTables[Idx];
789   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
790     if (JTE.MBBs[j] == Old) {
791       JTE.MBBs[j] = New;
792       MadeChange = true;
793     }
794   return MadeChange;
795 }
796 
print(raw_ostream & OS) const797 void MachineJumpTableInfo::print(raw_ostream &OS) const {
798   if (JumpTables.empty()) return;
799 
800   OS << "Jump Tables:\n";
801 
802   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
803     OS << "  jt#" << i << ": ";
804     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
805       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
806   }
807 
808   OS << '\n';
809 }
810 
811 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const812 void MachineJumpTableInfo::dump() const { print(dbgs()); }
813 #endif
814 
815 
816 //===----------------------------------------------------------------------===//
817 //  MachineConstantPool implementation
818 //===----------------------------------------------------------------------===//
819 
anchor()820 void MachineConstantPoolValue::anchor() { }
821 
getDataLayout() const822 const DataLayout *MachineConstantPool::getDataLayout() const {
823   return TM.getDataLayout();
824 }
825 
getType() const826 Type *MachineConstantPoolEntry::getType() const {
827   if (isMachineConstantPoolEntry())
828     return Val.MachineCPVal->getType();
829   return Val.ConstVal->getType();
830 }
831 
832 
getRelocationInfo() const833 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
834   if (isMachineConstantPoolEntry())
835     return Val.MachineCPVal->getRelocationInfo();
836   return Val.ConstVal->getRelocationInfo();
837 }
838 
~MachineConstantPool()839 MachineConstantPool::~MachineConstantPool() {
840   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
841     if (Constants[i].isMachineConstantPoolEntry())
842       delete Constants[i].Val.MachineCPVal;
843   for (DenseSet<MachineConstantPoolValue*>::iterator I =
844        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
845        I != E; ++I)
846     delete *I;
847 }
848 
849 /// CanShareConstantPoolEntry - Test whether the given two constants
850 /// can be allocated the same constant pool entry.
CanShareConstantPoolEntry(const Constant * A,const Constant * B,const DataLayout * TD)851 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
852                                       const DataLayout *TD) {
853   // Handle the trivial case quickly.
854   if (A == B) return true;
855 
856   // If they have the same type but weren't the same constant, quickly
857   // reject them.
858   if (A->getType() == B->getType()) return false;
859 
860   // We can't handle structs or arrays.
861   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
862       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
863     return false;
864 
865   // For now, only support constants with the same size.
866   uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
867   if (StoreSize != TD->getTypeStoreSize(B->getType()) || StoreSize > 128)
868     return false;
869 
870   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
871 
872   // Try constant folding a bitcast of both instructions to an integer.  If we
873   // get two identical ConstantInt's, then we are good to share them.  We use
874   // the constant folding APIs to do this so that we get the benefit of
875   // DataLayout.
876   if (isa<PointerType>(A->getType()))
877     A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
878                                  const_cast<Constant*>(A), TD);
879   else if (A->getType() != IntTy)
880     A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
881                                  const_cast<Constant*>(A), TD);
882   if (isa<PointerType>(B->getType()))
883     B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
884                                  const_cast<Constant*>(B), TD);
885   else if (B->getType() != IntTy)
886     B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
887                                  const_cast<Constant*>(B), TD);
888 
889   return A == B;
890 }
891 
892 /// getConstantPoolIndex - Create a new entry in the constant pool or return
893 /// an existing one.  User must specify the log2 of the minimum required
894 /// alignment for the object.
895 ///
getConstantPoolIndex(const Constant * C,unsigned Alignment)896 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
897                                                    unsigned Alignment) {
898   assert(Alignment && "Alignment must be specified!");
899   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
900 
901   // Check to see if we already have this constant.
902   //
903   // FIXME, this could be made much more efficient for large constant pools.
904   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
905     if (!Constants[i].isMachineConstantPoolEntry() &&
906         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C,
907                                   getDataLayout())) {
908       if ((unsigned)Constants[i].getAlignment() < Alignment)
909         Constants[i].Alignment = Alignment;
910       return i;
911     }
912 
913   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
914   return Constants.size()-1;
915 }
916 
getConstantPoolIndex(MachineConstantPoolValue * V,unsigned Alignment)917 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
918                                                    unsigned Alignment) {
919   assert(Alignment && "Alignment must be specified!");
920   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
921 
922   // Check to see if we already have this constant.
923   //
924   // FIXME, this could be made much more efficient for large constant pools.
925   int Idx = V->getExistingMachineCPValue(this, Alignment);
926   if (Idx != -1) {
927     MachineCPVsSharingEntries.insert(V);
928     return (unsigned)Idx;
929   }
930 
931   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
932   return Constants.size()-1;
933 }
934 
print(raw_ostream & OS) const935 void MachineConstantPool::print(raw_ostream &OS) const {
936   if (Constants.empty()) return;
937 
938   OS << "Constant Pool:\n";
939   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
940     OS << "  cp#" << i << ": ";
941     if (Constants[i].isMachineConstantPoolEntry())
942       Constants[i].Val.MachineCPVal->print(OS);
943     else
944       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
945     OS << ", align=" << Constants[i].getAlignment();
946     OS << "\n";
947   }
948 }
949 
950 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const951 void MachineConstantPool::dump() const { print(dbgs()); }
952 #endif
953