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 #include "llvm/Target/TargetSubtargetInfo.h"
40 using namespace llvm;
41 
42 #define DEBUG_TYPE "codegen"
43 
44 //===----------------------------------------------------------------------===//
45 // MachineFunction implementation
46 //===----------------------------------------------------------------------===//
47 
48 // Out of line virtual method.
~MachineFunctionInfo()49 MachineFunctionInfo::~MachineFunctionInfo() {}
50 
deleteNode(MachineBasicBlock * MBB)51 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
52   MBB->getParent()->DeleteMachineBasicBlock(MBB);
53 }
54 
MachineFunction(const Function * F,const TargetMachine & TM,unsigned FunctionNum,MachineModuleInfo & mmi)55 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
56                                  unsigned FunctionNum, MachineModuleInfo &mmi)
57     : Fn(F), Target(TM), STI(TM.getSubtargetImpl(*F)), Ctx(mmi.getContext()),
58       MMI(mmi) {
59   if (STI->getRegisterInfo())
60     RegInfo = new (Allocator) MachineRegisterInfo(this);
61   else
62     RegInfo = nullptr;
63 
64   MFInfo = nullptr;
65   FrameInfo = new (Allocator)
66       MachineFrameInfo(STI->getFrameLowering()->getStackAlignment(),
67                        STI->getFrameLowering()->isStackRealignable(),
68                        !F->hasFnAttribute("no-realign-stack"));
69 
70   if (Fn->hasFnAttribute(Attribute::StackAlignment))
71     FrameInfo->ensureMaxAlignment(Fn->getFnStackAlignment());
72 
73   ConstantPool = new (Allocator) MachineConstantPool(TM);
74   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
75 
76   // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
77   if (!Fn->hasFnAttribute(Attribute::OptimizeForSize))
78     Alignment = std::max(Alignment,
79                          STI->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 AAMDNodes & AAInfo,const MDNode * Ranges)230 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
231                                       uint64_t s, unsigned base_alignment,
232                                       const AAMDNodes &AAInfo,
233                                       const MDNode *Ranges) {
234   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
235                                            AAInfo, 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());
247   return new (Allocator)
248              MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(),
249                                                   MMO->getOffset()+Offset),
250                                MMO->getFlags(), Size,
251                                MMO->getBaseAlignment());
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)->getAAInfo());
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)->getAAInfo());
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 = getSubtarget().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() + "' function").str();
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);
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 
486 /// ensureMaxAlignment - Make sure the function is at least Align bytes
487 /// aligned.
ensureMaxAlignment(unsigned Align)488 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
489   if (!StackRealignable || !RealignOption)
490     assert(Align <= StackAlignment &&
491            "For targets without stack realignment, Align is out of limit!");
492   if (MaxAlignment < Align) MaxAlignment = Align;
493 }
494 
495 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
clampStackAlignment(bool ShouldClamp,unsigned Align,unsigned StackAlign)496 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
497                                            unsigned StackAlign) {
498   if (!ShouldClamp || Align <= StackAlign)
499     return Align;
500   DEBUG(dbgs() << "Warning: requested alignment " << Align
501                << " exceeds the stack alignment " << StackAlign
502                << " when stack realignment is off" << '\n');
503   return StackAlign;
504 }
505 
506 /// CreateStackObject - Create a new statically sized stack object, returning
507 /// a nonnegative identifier to represent it.
508 ///
CreateStackObject(uint64_t Size,unsigned Alignment,bool isSS,const AllocaInst * Alloca)509 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
510                       bool isSS, const AllocaInst *Alloca) {
511   assert(Size != 0 && "Cannot allocate zero size stack objects!");
512   Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
513                                   Alignment, StackAlignment);
514   Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, Alloca,
515                                 !isSS));
516   int Index = (int)Objects.size() - NumFixedObjects - 1;
517   assert(Index >= 0 && "Bad frame index!");
518   ensureMaxAlignment(Alignment);
519   return Index;
520 }
521 
522 /// CreateSpillStackObject - Create a new statically sized stack object that
523 /// represents a spill slot, returning a nonnegative identifier to represent
524 /// it.
525 ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)526 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
527                                              unsigned Alignment) {
528   Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
529                                   Alignment, StackAlignment);
530   CreateStackObject(Size, Alignment, true);
531   int Index = (int)Objects.size() - NumFixedObjects - 1;
532   ensureMaxAlignment(Alignment);
533   return Index;
534 }
535 
536 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
537 /// variable sized object has been created.  This must be created whenever a
538 /// variable sized object is created, whether or not the index returned is
539 /// actually used.
540 ///
CreateVariableSizedObject(unsigned Alignment,const AllocaInst * Alloca)541 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment,
542                                                 const AllocaInst *Alloca) {
543   HasVarSizedObjects = true;
544   Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
545                                   Alignment, StackAlignment);
546   Objects.push_back(StackObject(0, Alignment, 0, false, false, Alloca, true));
547   ensureMaxAlignment(Alignment);
548   return (int)Objects.size()-NumFixedObjects-1;
549 }
550 
551 /// CreateFixedObject - Create a new object at a fixed location on the stack.
552 /// All fixed objects should be created before other objects are created for
553 /// efficiency. By default, fixed objects are immutable. This returns an
554 /// index with a negative value.
555 ///
CreateFixedObject(uint64_t Size,int64_t SPOffset,bool Immutable,bool isAliased)556 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
557                                         bool Immutable, bool isAliased) {
558   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
559   // The alignment of the frame index can be determined from its offset from
560   // the incoming frame position.  If the frame object is at offset 32 and
561   // the stack is guaranteed to be 16-byte aligned, then we know that the
562   // object is 16-byte aligned.
563   unsigned Align = MinAlign(SPOffset, StackAlignment);
564   Align = clampStackAlignment(!StackRealignable || !RealignOption, Align,
565                               StackAlignment);
566   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
567                                               /*isSS*/   false,
568                                               /*Alloca*/ nullptr, isAliased));
569   return -++NumFixedObjects;
570 }
571 
572 /// CreateFixedSpillStackObject - Create a spill slot at a fixed location
573 /// on the stack.  Returns an index with a negative value.
CreateFixedSpillStackObject(uint64_t Size,int64_t SPOffset)574 int MachineFrameInfo::CreateFixedSpillStackObject(uint64_t Size,
575                                                   int64_t SPOffset) {
576   unsigned Align = MinAlign(SPOffset, StackAlignment);
577   Align = clampStackAlignment(!StackRealignable || !RealignOption, Align,
578                               StackAlignment);
579   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset,
580                                               /*Immutable*/ true,
581                                               /*isSS*/ true,
582                                               /*Alloca*/ nullptr,
583                                               /*isAliased*/ false));
584   return -++NumFixedObjects;
585 }
586 
587 BitVector
getPristineRegs(const MachineBasicBlock * MBB) const588 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
589   assert(MBB && "MBB must be valid");
590   const MachineFunction *MF = MBB->getParent();
591   assert(MF && "MBB must be part of a MachineFunction");
592   const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
593   BitVector BV(TRI->getNumRegs());
594 
595   // Before CSI is calculated, no registers are considered pristine. They can be
596   // freely used and PEI will make sure they are saved.
597   if (!isCalleeSavedInfoValid())
598     return BV;
599 
600   for (const MCPhysReg *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
601     BV.set(*CSR);
602 
603   // The entry MBB always has all CSRs pristine.
604   if (MBB == &MF->front())
605     return BV;
606 
607   // On other MBBs the saved CSRs are not pristine.
608   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
609   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
610          E = CSI.end(); I != E; ++I)
611     BV.reset(I->getReg());
612 
613   return BV;
614 }
615 
estimateStackSize(const MachineFunction & MF) const616 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
617   const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();
618   const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
619   unsigned MaxAlign = getMaxAlignment();
620   int Offset = 0;
621 
622   // This code is very, very similar to PEI::calculateFrameObjectOffsets().
623   // It really should be refactored to share code. Until then, changes
624   // should keep in mind that there's tight coupling between the two.
625 
626   for (int i = getObjectIndexBegin(); i != 0; ++i) {
627     int FixedOff = -getObjectOffset(i);
628     if (FixedOff > Offset) Offset = FixedOff;
629   }
630   for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
631     if (isDeadObjectIndex(i))
632       continue;
633     Offset += getObjectSize(i);
634     unsigned Align = getObjectAlignment(i);
635     // Adjust to alignment boundary
636     Offset = (Offset+Align-1)/Align*Align;
637 
638     MaxAlign = std::max(Align, MaxAlign);
639   }
640 
641   if (adjustsStack() && TFI->hasReservedCallFrame(MF))
642     Offset += getMaxCallFrameSize();
643 
644   // Round up the size to a multiple of the alignment.  If the function has
645   // any calls or alloca's, align to the target's StackAlignment value to
646   // ensure that the callee's frame or the alloca data is suitably aligned;
647   // otherwise, for leaf functions, align to the TransientStackAlignment
648   // value.
649   unsigned StackAlign;
650   if (adjustsStack() || hasVarSizedObjects() ||
651       (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
652     StackAlign = TFI->getStackAlignment();
653   else
654     StackAlign = TFI->getTransientStackAlignment();
655 
656   // If the frame pointer is eliminated, all frame offsets will be relative to
657   // SP not FP. Align to MaxAlign so this works.
658   StackAlign = std::max(StackAlign, MaxAlign);
659   unsigned AlignMask = StackAlign - 1;
660   Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
661 
662   return (unsigned)Offset;
663 }
664 
print(const MachineFunction & MF,raw_ostream & OS) const665 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
666   if (Objects.empty()) return;
667 
668   const TargetFrameLowering *FI = MF.getSubtarget().getFrameLowering();
669   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
670 
671   OS << "Frame Objects:\n";
672 
673   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
674     const StackObject &SO = Objects[i];
675     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
676     if (SO.Size == ~0ULL) {
677       OS << "dead\n";
678       continue;
679     }
680     if (SO.Size == 0)
681       OS << "variable sized";
682     else
683       OS << "size=" << SO.Size;
684     OS << ", align=" << SO.Alignment;
685 
686     if (i < NumFixedObjects)
687       OS << ", fixed";
688     if (i < NumFixedObjects || SO.SPOffset != -1) {
689       int64_t Off = SO.SPOffset - ValOffset;
690       OS << ", at location [SP";
691       if (Off > 0)
692         OS << "+" << Off;
693       else if (Off < 0)
694         OS << Off;
695       OS << "]";
696     }
697     OS << "\n";
698   }
699 }
700 
701 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump(const MachineFunction & MF) const702 void MachineFrameInfo::dump(const MachineFunction &MF) const {
703   print(MF, dbgs());
704 }
705 #endif
706 
707 //===----------------------------------------------------------------------===//
708 //  MachineJumpTableInfo implementation
709 //===----------------------------------------------------------------------===//
710 
711 /// getEntrySize - Return the size of each entry in the jump table.
getEntrySize(const DataLayout & TD) const712 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
713   // The size of a jump table entry is 4 bytes unless the entry is just the
714   // address of a block, in which case it is the pointer size.
715   switch (getEntryKind()) {
716   case MachineJumpTableInfo::EK_BlockAddress:
717     return TD.getPointerSize();
718   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
719     return 8;
720   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
721   case MachineJumpTableInfo::EK_LabelDifference32:
722   case MachineJumpTableInfo::EK_Custom32:
723     return 4;
724   case MachineJumpTableInfo::EK_Inline:
725     return 0;
726   }
727   llvm_unreachable("Unknown jump table encoding!");
728 }
729 
730 /// getEntryAlignment - Return the alignment of each entry in the jump table.
getEntryAlignment(const DataLayout & TD) const731 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
732   // The alignment of a jump table entry is the alignment of int32 unless the
733   // entry is just the address of a block, in which case it is the pointer
734   // alignment.
735   switch (getEntryKind()) {
736   case MachineJumpTableInfo::EK_BlockAddress:
737     return TD.getPointerABIAlignment();
738   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
739     return TD.getABIIntegerTypeAlignment(64);
740   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
741   case MachineJumpTableInfo::EK_LabelDifference32:
742   case MachineJumpTableInfo::EK_Custom32:
743     return TD.getABIIntegerTypeAlignment(32);
744   case MachineJumpTableInfo::EK_Inline:
745     return 1;
746   }
747   llvm_unreachable("Unknown jump table encoding!");
748 }
749 
750 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
751 ///
createJumpTableIndex(const std::vector<MachineBasicBlock * > & DestBBs)752 unsigned MachineJumpTableInfo::createJumpTableIndex(
753                                const std::vector<MachineBasicBlock*> &DestBBs) {
754   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
755   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
756   return JumpTables.size()-1;
757 }
758 
759 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
760 /// the jump tables to branch to New instead.
ReplaceMBBInJumpTables(MachineBasicBlock * Old,MachineBasicBlock * New)761 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
762                                                   MachineBasicBlock *New) {
763   assert(Old != New && "Not making a change?");
764   bool MadeChange = false;
765   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
766     ReplaceMBBInJumpTable(i, Old, New);
767   return MadeChange;
768 }
769 
770 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
771 /// the jump table to branch to New instead.
ReplaceMBBInJumpTable(unsigned Idx,MachineBasicBlock * Old,MachineBasicBlock * New)772 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
773                                                  MachineBasicBlock *Old,
774                                                  MachineBasicBlock *New) {
775   assert(Old != New && "Not making a change?");
776   bool MadeChange = false;
777   MachineJumpTableEntry &JTE = JumpTables[Idx];
778   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
779     if (JTE.MBBs[j] == Old) {
780       JTE.MBBs[j] = New;
781       MadeChange = true;
782     }
783   return MadeChange;
784 }
785 
print(raw_ostream & OS) const786 void MachineJumpTableInfo::print(raw_ostream &OS) const {
787   if (JumpTables.empty()) return;
788 
789   OS << "Jump Tables:\n";
790 
791   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
792     OS << "  jt#" << i << ": ";
793     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
794       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
795   }
796 
797   OS << '\n';
798 }
799 
800 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const801 void MachineJumpTableInfo::dump() const { print(dbgs()); }
802 #endif
803 
804 
805 //===----------------------------------------------------------------------===//
806 //  MachineConstantPool implementation
807 //===----------------------------------------------------------------------===//
808 
anchor()809 void MachineConstantPoolValue::anchor() { }
810 
getDataLayout() const811 const DataLayout *MachineConstantPool::getDataLayout() const {
812   return TM.getDataLayout();
813 }
814 
getType() const815 Type *MachineConstantPoolEntry::getType() const {
816   if (isMachineConstantPoolEntry())
817     return Val.MachineCPVal->getType();
818   return Val.ConstVal->getType();
819 }
820 
821 
getRelocationInfo() const822 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
823   if (isMachineConstantPoolEntry())
824     return Val.MachineCPVal->getRelocationInfo();
825   return Val.ConstVal->getRelocationInfo();
826 }
827 
828 SectionKind
getSectionKind(const DataLayout * DL) const829 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
830   SectionKind Kind;
831   switch (getRelocationInfo()) {
832   default:
833     llvm_unreachable("Unknown section kind");
834   case Constant::GlobalRelocations:
835     Kind = SectionKind::getReadOnlyWithRel();
836     break;
837   case Constant::LocalRelocation:
838     Kind = SectionKind::getReadOnlyWithRelLocal();
839     break;
840   case Constant::NoRelocation:
841     switch (DL->getTypeAllocSize(getType())) {
842     case 4:
843       Kind = SectionKind::getMergeableConst4();
844       break;
845     case 8:
846       Kind = SectionKind::getMergeableConst8();
847       break;
848     case 16:
849       Kind = SectionKind::getMergeableConst16();
850       break;
851     default:
852       Kind = SectionKind::getReadOnly();
853       break;
854     }
855   }
856   return Kind;
857 }
858 
~MachineConstantPool()859 MachineConstantPool::~MachineConstantPool() {
860   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
861     if (Constants[i].isMachineConstantPoolEntry())
862       delete Constants[i].Val.MachineCPVal;
863   for (DenseSet<MachineConstantPoolValue*>::iterator I =
864        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
865        I != E; ++I)
866     delete *I;
867 }
868 
869 /// CanShareConstantPoolEntry - Test whether the given two constants
870 /// can be allocated the same constant pool entry.
CanShareConstantPoolEntry(const Constant * A,const Constant * B,const DataLayout * TD)871 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
872                                       const DataLayout *TD) {
873   // Handle the trivial case quickly.
874   if (A == B) return true;
875 
876   // If they have the same type but weren't the same constant, quickly
877   // reject them.
878   if (A->getType() == B->getType()) return false;
879 
880   // We can't handle structs or arrays.
881   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
882       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
883     return false;
884 
885   // For now, only support constants with the same size.
886   uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
887   if (StoreSize != TD->getTypeStoreSize(B->getType()) || StoreSize > 128)
888     return false;
889 
890   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
891 
892   // Try constant folding a bitcast of both instructions to an integer.  If we
893   // get two identical ConstantInt's, then we are good to share them.  We use
894   // the constant folding APIs to do this so that we get the benefit of
895   // DataLayout.
896   if (isa<PointerType>(A->getType()))
897     A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
898                                  const_cast<Constant *>(A), *TD);
899   else if (A->getType() != IntTy)
900     A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
901                                  const_cast<Constant *>(A), *TD);
902   if (isa<PointerType>(B->getType()))
903     B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
904                                  const_cast<Constant *>(B), *TD);
905   else if (B->getType() != IntTy)
906     B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
907                                  const_cast<Constant *>(B), *TD);
908 
909   return A == B;
910 }
911 
912 /// getConstantPoolIndex - Create a new entry in the constant pool or return
913 /// an existing one.  User must specify the log2 of the minimum required
914 /// alignment for the object.
915 ///
getConstantPoolIndex(const Constant * C,unsigned Alignment)916 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
917                                                    unsigned Alignment) {
918   assert(Alignment && "Alignment must be specified!");
919   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
920 
921   // Check to see if we already have this constant.
922   //
923   // FIXME, this could be made much more efficient for large constant pools.
924   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
925     if (!Constants[i].isMachineConstantPoolEntry() &&
926         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C,
927                                   getDataLayout())) {
928       if ((unsigned)Constants[i].getAlignment() < Alignment)
929         Constants[i].Alignment = Alignment;
930       return i;
931     }
932 
933   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
934   return Constants.size()-1;
935 }
936 
getConstantPoolIndex(MachineConstantPoolValue * V,unsigned Alignment)937 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
938                                                    unsigned Alignment) {
939   assert(Alignment && "Alignment must be specified!");
940   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
941 
942   // Check to see if we already have this constant.
943   //
944   // FIXME, this could be made much more efficient for large constant pools.
945   int Idx = V->getExistingMachineCPValue(this, Alignment);
946   if (Idx != -1) {
947     MachineCPVsSharingEntries.insert(V);
948     return (unsigned)Idx;
949   }
950 
951   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
952   return Constants.size()-1;
953 }
954 
print(raw_ostream & OS) const955 void MachineConstantPool::print(raw_ostream &OS) const {
956   if (Constants.empty()) return;
957 
958   OS << "Constant Pool:\n";
959   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
960     OS << "  cp#" << i << ": ";
961     if (Constants[i].isMachineConstantPoolEntry())
962       Constants[i].Val.MachineCPVal->print(OS);
963     else
964       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
965     OS << ", align=" << Constants[i].getAlignment();
966     OS << "\n";
967   }
968 }
969 
970 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const971 void MachineConstantPool::dump() const { print(dbgs()); }
972 #endif
973