xref: /freebsd/contrib/llvm-project/llvm/lib/CodeGen/MachineFunction.cpp (revision 162ae9c834f6d9f9cb443bd62cceb23e0b5fef48)
1 //===- MachineFunction.cpp ------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Collect native machine code information for a function.  This allows
10 // target-specific information about the generated code to be stored with each
11 // function.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/CodeGen/MachineFunction.h"
16 #include "llvm/ADT/BitVector.h"
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/DenseSet.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Analysis/ConstantFolding.h"
25 #include "llvm/Analysis/EHPersonalities.h"
26 #include "llvm/CodeGen/MachineBasicBlock.h"
27 #include "llvm/CodeGen/MachineConstantPool.h"
28 #include "llvm/CodeGen/MachineFrameInfo.h"
29 #include "llvm/CodeGen/MachineInstr.h"
30 #include "llvm/CodeGen/MachineJumpTableInfo.h"
31 #include "llvm/CodeGen/MachineMemOperand.h"
32 #include "llvm/CodeGen/MachineModuleInfo.h"
33 #include "llvm/CodeGen/MachineRegisterInfo.h"
34 #include "llvm/CodeGen/PseudoSourceValue.h"
35 #include "llvm/CodeGen/TargetFrameLowering.h"
36 #include "llvm/CodeGen/TargetLowering.h"
37 #include "llvm/CodeGen/TargetRegisterInfo.h"
38 #include "llvm/CodeGen/TargetSubtargetInfo.h"
39 #include "llvm/CodeGen/WasmEHFuncInfo.h"
40 #include "llvm/CodeGen/WinEHFuncInfo.h"
41 #include "llvm/Config/llvm-config.h"
42 #include "llvm/IR/Attributes.h"
43 #include "llvm/IR/BasicBlock.h"
44 #include "llvm/IR/Constant.h"
45 #include "llvm/IR/DataLayout.h"
46 #include "llvm/IR/DebugInfoMetadata.h"
47 #include "llvm/IR/DerivedTypes.h"
48 #include "llvm/IR/Function.h"
49 #include "llvm/IR/GlobalValue.h"
50 #include "llvm/IR/Instruction.h"
51 #include "llvm/IR/Instructions.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSlotTracker.h"
55 #include "llvm/IR/Value.h"
56 #include "llvm/MC/MCContext.h"
57 #include "llvm/MC/MCSymbol.h"
58 #include "llvm/MC/SectionKind.h"
59 #include "llvm/Support/Casting.h"
60 #include "llvm/Support/CommandLine.h"
61 #include "llvm/Support/Compiler.h"
62 #include "llvm/Support/DOTGraphTraits.h"
63 #include "llvm/Support/Debug.h"
64 #include "llvm/Support/ErrorHandling.h"
65 #include "llvm/Support/GraphWriter.h"
66 #include "llvm/Support/raw_ostream.h"
67 #include "llvm/Target/TargetMachine.h"
68 #include <algorithm>
69 #include <cassert>
70 #include <cstddef>
71 #include <cstdint>
72 #include <iterator>
73 #include <string>
74 #include <utility>
75 #include <vector>
76 
77 using namespace llvm;
78 
79 #define DEBUG_TYPE "codegen"
80 
81 static cl::opt<unsigned>
82 AlignAllFunctions("align-all-functions",
83                   cl::desc("Force the alignment of all functions."),
84                   cl::init(0), cl::Hidden);
85 
86 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
87   using P = MachineFunctionProperties::Property;
88 
89   switch(Prop) {
90   case P::FailedISel: return "FailedISel";
91   case P::IsSSA: return "IsSSA";
92   case P::Legalized: return "Legalized";
93   case P::NoPHIs: return "NoPHIs";
94   case P::NoVRegs: return "NoVRegs";
95   case P::RegBankSelected: return "RegBankSelected";
96   case P::Selected: return "Selected";
97   case P::TracksLiveness: return "TracksLiveness";
98   }
99   llvm_unreachable("Invalid machine function property");
100 }
101 
102 // Pin the vtable to this file.
103 void MachineFunction::Delegate::anchor() {}
104 
105 void MachineFunctionProperties::print(raw_ostream &OS) const {
106   const char *Separator = "";
107   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
108     if (!Properties[I])
109       continue;
110     OS << Separator << getPropertyName(static_cast<Property>(I));
111     Separator = ", ";
112   }
113 }
114 
115 //===----------------------------------------------------------------------===//
116 // MachineFunction implementation
117 //===----------------------------------------------------------------------===//
118 
119 // Out-of-line virtual method.
120 MachineFunctionInfo::~MachineFunctionInfo() = default;
121 
122 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
123   MBB->getParent()->DeleteMachineBasicBlock(MBB);
124 }
125 
126 static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
127                                            const Function &F) {
128   if (F.hasFnAttribute(Attribute::StackAlignment))
129     return F.getFnStackAlignment();
130   return STI->getFrameLowering()->getStackAlignment();
131 }
132 
133 MachineFunction::MachineFunction(const Function &F,
134                                  const LLVMTargetMachine &Target,
135                                  const TargetSubtargetInfo &STI,
136                                  unsigned FunctionNum, MachineModuleInfo &mmi)
137     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
138   FunctionNumber = FunctionNum;
139   init();
140 }
141 
142 void MachineFunction::handleInsertion(MachineInstr &MI) {
143   if (TheDelegate)
144     TheDelegate->MF_HandleInsertion(MI);
145 }
146 
147 void MachineFunction::handleRemoval(MachineInstr &MI) {
148   if (TheDelegate)
149     TheDelegate->MF_HandleRemoval(MI);
150 }
151 
152 void MachineFunction::init() {
153   // Assume the function starts in SSA form with correct liveness.
154   Properties.set(MachineFunctionProperties::Property::IsSSA);
155   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
156   if (STI->getRegisterInfo())
157     RegInfo = new (Allocator) MachineRegisterInfo(this);
158   else
159     RegInfo = nullptr;
160 
161   MFInfo = nullptr;
162   // We can realign the stack if the target supports it and the user hasn't
163   // explicitly asked us not to.
164   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
165                       !F.hasFnAttribute("no-realign-stack");
166   FrameInfo = new (Allocator) MachineFrameInfo(
167       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
168       /*ForcedRealign=*/CanRealignSP &&
169           F.hasFnAttribute(Attribute::StackAlignment));
170 
171   if (F.hasFnAttribute(Attribute::StackAlignment))
172     FrameInfo->ensureMaxAlignment(F.getFnStackAlignment());
173 
174   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
175   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
176 
177   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
178   // FIXME: Use Function::hasOptSize().
179   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
180     Alignment = std::max(Alignment,
181                          STI->getTargetLowering()->getPrefFunctionAlignment());
182 
183   if (AlignAllFunctions)
184     Alignment = AlignAllFunctions;
185 
186   JumpTableInfo = nullptr;
187 
188   if (isFuncletEHPersonality(classifyEHPersonality(
189           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
190     WinEHInfo = new (Allocator) WinEHFuncInfo();
191   }
192 
193   if (isScopedEHPersonality(classifyEHPersonality(
194           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
195     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
196   }
197 
198   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
199          "Can't create a MachineFunction using a Module with a "
200          "Target-incompatible DataLayout attached\n");
201 
202   PSVManager =
203     llvm::make_unique<PseudoSourceValueManager>(*(getSubtarget().
204                                                   getInstrInfo()));
205 }
206 
207 MachineFunction::~MachineFunction() {
208   clear();
209 }
210 
211 void MachineFunction::clear() {
212   Properties.reset();
213   // Don't call destructors on MachineInstr and MachineOperand. All of their
214   // memory comes from the BumpPtrAllocator which is about to be purged.
215   //
216   // Do call MachineBasicBlock destructors, it contains std::vectors.
217   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
218     I->Insts.clearAndLeakNodesUnsafely();
219   MBBNumbering.clear();
220 
221   InstructionRecycler.clear(Allocator);
222   OperandRecycler.clear(Allocator);
223   BasicBlockRecycler.clear(Allocator);
224   CodeViewAnnotations.clear();
225   VariableDbgInfos.clear();
226   if (RegInfo) {
227     RegInfo->~MachineRegisterInfo();
228     Allocator.Deallocate(RegInfo);
229   }
230   if (MFInfo) {
231     MFInfo->~MachineFunctionInfo();
232     Allocator.Deallocate(MFInfo);
233   }
234 
235   FrameInfo->~MachineFrameInfo();
236   Allocator.Deallocate(FrameInfo);
237 
238   ConstantPool->~MachineConstantPool();
239   Allocator.Deallocate(ConstantPool);
240 
241   if (JumpTableInfo) {
242     JumpTableInfo->~MachineJumpTableInfo();
243     Allocator.Deallocate(JumpTableInfo);
244   }
245 
246   if (WinEHInfo) {
247     WinEHInfo->~WinEHFuncInfo();
248     Allocator.Deallocate(WinEHInfo);
249   }
250 
251   if (WasmEHInfo) {
252     WasmEHInfo->~WasmEHFuncInfo();
253     Allocator.Deallocate(WasmEHInfo);
254   }
255 }
256 
257 const DataLayout &MachineFunction::getDataLayout() const {
258   return F.getParent()->getDataLayout();
259 }
260 
261 /// Get the JumpTableInfo for this function.
262 /// If it does not already exist, allocate one.
263 MachineJumpTableInfo *MachineFunction::
264 getOrCreateJumpTableInfo(unsigned EntryKind) {
265   if (JumpTableInfo) return JumpTableInfo;
266 
267   JumpTableInfo = new (Allocator)
268     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
269   return JumpTableInfo;
270 }
271 
272 /// Should we be emitting segmented stack stuff for the function
273 bool MachineFunction::shouldSplitStack() const {
274   return getFunction().hasFnAttribute("split-stack");
275 }
276 
277 LLVM_NODISCARD unsigned
278 MachineFunction::addFrameInst(const MCCFIInstruction &Inst) {
279   FrameInstructions.push_back(Inst);
280   return FrameInstructions.size() - 1;
281 }
282 
283 /// This discards all of the MachineBasicBlock numbers and recomputes them.
284 /// This guarantees that the MBB numbers are sequential, dense, and match the
285 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
286 /// is specified, only that block and those after it are renumbered.
287 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
288   if (empty()) { MBBNumbering.clear(); return; }
289   MachineFunction::iterator MBBI, E = end();
290   if (MBB == nullptr)
291     MBBI = begin();
292   else
293     MBBI = MBB->getIterator();
294 
295   // Figure out the block number this should have.
296   unsigned BlockNo = 0;
297   if (MBBI != begin())
298     BlockNo = std::prev(MBBI)->getNumber() + 1;
299 
300   for (; MBBI != E; ++MBBI, ++BlockNo) {
301     if (MBBI->getNumber() != (int)BlockNo) {
302       // Remove use of the old number.
303       if (MBBI->getNumber() != -1) {
304         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
305                "MBB number mismatch!");
306         MBBNumbering[MBBI->getNumber()] = nullptr;
307       }
308 
309       // If BlockNo is already taken, set that block's number to -1.
310       if (MBBNumbering[BlockNo])
311         MBBNumbering[BlockNo]->setNumber(-1);
312 
313       MBBNumbering[BlockNo] = &*MBBI;
314       MBBI->setNumber(BlockNo);
315     }
316   }
317 
318   // Okay, all the blocks are renumbered.  If we have compactified the block
319   // numbering, shrink MBBNumbering now.
320   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
321   MBBNumbering.resize(BlockNo);
322 }
323 
324 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
325 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
326                                                   const DebugLoc &DL,
327                                                   bool NoImp) {
328   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
329     MachineInstr(*this, MCID, DL, NoImp);
330 }
331 
332 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
333 /// identical in all ways except the instruction has no parent, prev, or next.
334 MachineInstr *
335 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
336   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
337              MachineInstr(*this, *Orig);
338 }
339 
340 MachineInstr &MachineFunction::CloneMachineInstrBundle(MachineBasicBlock &MBB,
341     MachineBasicBlock::iterator InsertBefore, const MachineInstr &Orig) {
342   MachineInstr *FirstClone = nullptr;
343   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
344   while (true) {
345     MachineInstr *Cloned = CloneMachineInstr(&*I);
346     MBB.insert(InsertBefore, Cloned);
347     if (FirstClone == nullptr) {
348       FirstClone = Cloned;
349     } else {
350       Cloned->bundleWithPred();
351     }
352 
353     if (!I->isBundledWithSucc())
354       break;
355     ++I;
356   }
357   return *FirstClone;
358 }
359 
360 /// Delete the given MachineInstr.
361 ///
362 /// This function also serves as the MachineInstr destructor - the real
363 /// ~MachineInstr() destructor must be empty.
364 void
365 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
366   // Verify that a call site info is at valid state. This assertion should
367   // be triggered during the implementation of support for the
368   // call site info of a new architecture. If the assertion is triggered,
369   // back trace will tell where to insert a call to updateCallSiteInfo().
370   assert((!MI->isCall(MachineInstr::IgnoreBundle) ||
371           CallSitesInfo.find(MI) == CallSitesInfo.end()) &&
372          "Call site info was not updated!");
373   // Strip it for parts. The operand array and the MI object itself are
374   // independently recyclable.
375   if (MI->Operands)
376     deallocateOperandArray(MI->CapOperands, MI->Operands);
377   // Don't call ~MachineInstr() which must be trivial anyway because
378   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
379   // destructors.
380   InstructionRecycler.Deallocate(Allocator, MI);
381 }
382 
383 /// Allocate a new MachineBasicBlock. Use this instead of
384 /// `new MachineBasicBlock'.
385 MachineBasicBlock *
386 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
387   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
388              MachineBasicBlock(*this, bb);
389 }
390 
391 /// Delete the given MachineBasicBlock.
392 void
393 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
394   assert(MBB->getParent() == this && "MBB parent mismatch!");
395   MBB->~MachineBasicBlock();
396   BasicBlockRecycler.Deallocate(Allocator, MBB);
397 }
398 
399 MachineMemOperand *MachineFunction::getMachineMemOperand(
400     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
401     unsigned base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
402     SyncScope::ID SSID, AtomicOrdering Ordering,
403     AtomicOrdering FailureOrdering) {
404   return new (Allocator)
405       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
406                         SSID, Ordering, FailureOrdering);
407 }
408 
409 MachineMemOperand *
410 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
411                                       int64_t Offset, uint64_t Size) {
412   const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
413 
414   // If there is no pointer value, the offset isn't tracked so we need to adjust
415   // the base alignment.
416   unsigned Align = PtrInfo.V.isNull()
417                        ? MinAlign(MMO->getBaseAlignment(), Offset)
418                        : MMO->getBaseAlignment();
419 
420   return new (Allocator)
421       MachineMemOperand(PtrInfo.getWithOffset(Offset), MMO->getFlags(), Size,
422                         Align, AAMDNodes(), nullptr, MMO->getSyncScopeID(),
423                         MMO->getOrdering(), MMO->getFailureOrdering());
424 }
425 
426 MachineMemOperand *
427 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
428                                       const AAMDNodes &AAInfo) {
429   MachinePointerInfo MPI = MMO->getValue() ?
430              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
431              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
432 
433   return new (Allocator)
434              MachineMemOperand(MPI, MMO->getFlags(), MMO->getSize(),
435                                MMO->getBaseAlignment(), AAInfo,
436                                MMO->getRanges(), MMO->getSyncScopeID(),
437                                MMO->getOrdering(), MMO->getFailureOrdering());
438 }
439 
440 MachineMemOperand *
441 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
442                                       MachineMemOperand::Flags Flags) {
443   return new (Allocator) MachineMemOperand(
444       MMO->getPointerInfo(), Flags, MMO->getSize(), MMO->getBaseAlignment(),
445       MMO->getAAInfo(), MMO->getRanges(), MMO->getSyncScopeID(),
446       MMO->getOrdering(), MMO->getFailureOrdering());
447 }
448 
449 MachineInstr::ExtraInfo *
450 MachineFunction::createMIExtraInfo(ArrayRef<MachineMemOperand *> MMOs,
451                                    MCSymbol *PreInstrSymbol,
452                                    MCSymbol *PostInstrSymbol) {
453   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
454                                          PostInstrSymbol, nullptr);
455 }
456 
457 MachineInstr::ExtraInfo *MachineFunction::createMIExtraInfoWithMarker(
458     ArrayRef<MachineMemOperand *> MMOs, MCSymbol *PreInstrSymbol,
459     MCSymbol *PostInstrSymbol, MDNode *HeapAllocMarker) {
460   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
461                                          PostInstrSymbol, HeapAllocMarker);
462 }
463 
464 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
465   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
466   llvm::copy(Name, Dest);
467   Dest[Name.size()] = 0;
468   return Dest;
469 }
470 
471 uint32_t *MachineFunction::allocateRegMask() {
472   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
473   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
474   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
475   memset(Mask, 0, Size * sizeof(Mask[0]));
476   return Mask;
477 }
478 
479 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
480 LLVM_DUMP_METHOD void MachineFunction::dump() const {
481   print(dbgs());
482 }
483 #endif
484 
485 StringRef MachineFunction::getName() const {
486   return getFunction().getName();
487 }
488 
489 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
490   OS << "# Machine code for function " << getName() << ": ";
491   getProperties().print(OS);
492   OS << '\n';
493 
494   // Print Frame Information
495   FrameInfo->print(*this, OS);
496 
497   // Print JumpTable Information
498   if (JumpTableInfo)
499     JumpTableInfo->print(OS);
500 
501   // Print Constant Pool
502   ConstantPool->print(OS);
503 
504   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
505 
506   if (RegInfo && !RegInfo->livein_empty()) {
507     OS << "Function Live Ins: ";
508     for (MachineRegisterInfo::livein_iterator
509          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
510       OS << printReg(I->first, TRI);
511       if (I->second)
512         OS << " in " << printReg(I->second, TRI);
513       if (std::next(I) != E)
514         OS << ", ";
515     }
516     OS << '\n';
517   }
518 
519   ModuleSlotTracker MST(getFunction().getParent());
520   MST.incorporateFunction(getFunction());
521   for (const auto &BB : *this) {
522     OS << '\n';
523     // If we print the whole function, print it at its most verbose level.
524     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
525   }
526 
527   OS << "\n# End machine code for function " << getName() << ".\n\n";
528 }
529 
530 namespace llvm {
531 
532   template<>
533   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
534     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
535 
536     static std::string getGraphName(const MachineFunction *F) {
537       return ("CFG for '" + F->getName() + "' function").str();
538     }
539 
540     std::string getNodeLabel(const MachineBasicBlock *Node,
541                              const MachineFunction *Graph) {
542       std::string OutStr;
543       {
544         raw_string_ostream OSS(OutStr);
545 
546         if (isSimple()) {
547           OSS << printMBBReference(*Node);
548           if (const BasicBlock *BB = Node->getBasicBlock())
549             OSS << ": " << BB->getName();
550         } else
551           Node->print(OSS);
552       }
553 
554       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
555 
556       // Process string output to make it nicer...
557       for (unsigned i = 0; i != OutStr.length(); ++i)
558         if (OutStr[i] == '\n') {                            // Left justify
559           OutStr[i] = '\\';
560           OutStr.insert(OutStr.begin()+i+1, 'l');
561         }
562       return OutStr;
563     }
564   };
565 
566 } // end namespace llvm
567 
568 void MachineFunction::viewCFG() const
569 {
570 #ifndef NDEBUG
571   ViewGraph(this, "mf" + getName());
572 #else
573   errs() << "MachineFunction::viewCFG is only available in debug builds on "
574          << "systems with Graphviz or gv!\n";
575 #endif // NDEBUG
576 }
577 
578 void MachineFunction::viewCFGOnly() const
579 {
580 #ifndef NDEBUG
581   ViewGraph(this, "mf" + getName(), true);
582 #else
583   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
584          << "systems with Graphviz or gv!\n";
585 #endif // NDEBUG
586 }
587 
588 /// Add the specified physical register as a live-in value and
589 /// create a corresponding virtual register for it.
590 unsigned MachineFunction::addLiveIn(unsigned PReg,
591                                     const TargetRegisterClass *RC) {
592   MachineRegisterInfo &MRI = getRegInfo();
593   unsigned VReg = MRI.getLiveInVirtReg(PReg);
594   if (VReg) {
595     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
596     (void)VRegRC;
597     // A physical register can be added several times.
598     // Between two calls, the register class of the related virtual register
599     // may have been constrained to match some operation constraints.
600     // In that case, check that the current register class includes the
601     // physical register and is a sub class of the specified RC.
602     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
603                              RC->hasSubClassEq(VRegRC))) &&
604             "Register class mismatch!");
605     return VReg;
606   }
607   VReg = MRI.createVirtualRegister(RC);
608   MRI.addLiveIn(PReg, VReg);
609   return VReg;
610 }
611 
612 /// Return the MCSymbol for the specified non-empty jump table.
613 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
614 /// normal 'L' label is returned.
615 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
616                                         bool isLinkerPrivate) const {
617   const DataLayout &DL = getDataLayout();
618   assert(JumpTableInfo && "No jump tables");
619   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
620 
621   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
622                                      : DL.getPrivateGlobalPrefix();
623   SmallString<60> Name;
624   raw_svector_ostream(Name)
625     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
626   return Ctx.getOrCreateSymbol(Name);
627 }
628 
629 /// Return a function-local symbol to represent the PIC base.
630 MCSymbol *MachineFunction::getPICBaseSymbol() const {
631   const DataLayout &DL = getDataLayout();
632   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
633                                Twine(getFunctionNumber()) + "$pb");
634 }
635 
636 /// \name Exception Handling
637 /// \{
638 
639 LandingPadInfo &
640 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
641   unsigned N = LandingPads.size();
642   for (unsigned i = 0; i < N; ++i) {
643     LandingPadInfo &LP = LandingPads[i];
644     if (LP.LandingPadBlock == LandingPad)
645       return LP;
646   }
647 
648   LandingPads.push_back(LandingPadInfo(LandingPad));
649   return LandingPads[N];
650 }
651 
652 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
653                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
654   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
655   LP.BeginLabels.push_back(BeginLabel);
656   LP.EndLabels.push_back(EndLabel);
657 }
658 
659 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
660   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
661   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
662   LP.LandingPadLabel = LandingPadLabel;
663 
664   const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
665   if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
666     if (const auto *PF =
667             dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
668       getMMI().addPersonality(PF);
669 
670     if (LPI->isCleanup())
671       addCleanup(LandingPad);
672 
673     // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
674     //        correct, but we need to do it this way because of how the DWARF EH
675     //        emitter processes the clauses.
676     for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
677       Value *Val = LPI->getClause(I - 1);
678       if (LPI->isCatch(I - 1)) {
679         addCatchTypeInfo(LandingPad,
680                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
681       } else {
682         // Add filters in a list.
683         auto *CVal = cast<Constant>(Val);
684         SmallVector<const GlobalValue *, 4> FilterList;
685         for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
686              II != IE; ++II)
687           FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
688 
689         addFilterTypeInfo(LandingPad, FilterList);
690       }
691     }
692 
693   } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
694     for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
695       Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
696       addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
697     }
698 
699   } else {
700     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
701   }
702 
703   return LandingPadLabel;
704 }
705 
706 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
707                                        ArrayRef<const GlobalValue *> TyInfo) {
708   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
709   for (unsigned N = TyInfo.size(); N; --N)
710     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
711 }
712 
713 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
714                                         ArrayRef<const GlobalValue *> TyInfo) {
715   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
716   std::vector<unsigned> IdsInFilter(TyInfo.size());
717   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
718     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
719   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
720 }
721 
722 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
723                                       bool TidyIfNoBeginLabels) {
724   for (unsigned i = 0; i != LandingPads.size(); ) {
725     LandingPadInfo &LandingPad = LandingPads[i];
726     if (LandingPad.LandingPadLabel &&
727         !LandingPad.LandingPadLabel->isDefined() &&
728         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
729       LandingPad.LandingPadLabel = nullptr;
730 
731     // Special case: we *should* emit LPs with null LP MBB. This indicates
732     // "nounwind" case.
733     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
734       LandingPads.erase(LandingPads.begin() + i);
735       continue;
736     }
737 
738     if (TidyIfNoBeginLabels) {
739       for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
740         MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
741         MCSymbol *EndLabel = LandingPad.EndLabels[j];
742         if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
743             (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
744           continue;
745 
746         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
747         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
748         --j;
749         --e;
750       }
751 
752       // Remove landing pads with no try-ranges.
753       if (LandingPads[i].BeginLabels.empty()) {
754         LandingPads.erase(LandingPads.begin() + i);
755         continue;
756       }
757     }
758 
759     // If there is no landing pad, ensure that the list of typeids is empty.
760     // If the only typeid is a cleanup, this is the same as having no typeids.
761     if (!LandingPad.LandingPadBlock ||
762         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
763       LandingPad.TypeIds.clear();
764     ++i;
765   }
766 }
767 
768 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
769   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
770   LP.TypeIds.push_back(0);
771 }
772 
773 void MachineFunction::addSEHCatchHandler(MachineBasicBlock *LandingPad,
774                                          const Function *Filter,
775                                          const BlockAddress *RecoverBA) {
776   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
777   SEHHandler Handler;
778   Handler.FilterOrFinally = Filter;
779   Handler.RecoverBA = RecoverBA;
780   LP.SEHHandlers.push_back(Handler);
781 }
782 
783 void MachineFunction::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
784                                            const Function *Cleanup) {
785   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
786   SEHHandler Handler;
787   Handler.FilterOrFinally = Cleanup;
788   Handler.RecoverBA = nullptr;
789   LP.SEHHandlers.push_back(Handler);
790 }
791 
792 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym,
793                                             ArrayRef<unsigned> Sites) {
794   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
795 }
796 
797 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) {
798   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
799     if (TypeInfos[i] == TI) return i + 1;
800 
801   TypeInfos.push_back(TI);
802   return TypeInfos.size();
803 }
804 
805 int MachineFunction::getFilterIDFor(std::vector<unsigned> &TyIds) {
806   // If the new filter coincides with the tail of an existing filter, then
807   // re-use the existing filter.  Folding filters more than this requires
808   // re-ordering filters and/or their elements - probably not worth it.
809   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
810        E = FilterEnds.end(); I != E; ++I) {
811     unsigned i = *I, j = TyIds.size();
812 
813     while (i && j)
814       if (FilterIds[--i] != TyIds[--j])
815         goto try_next;
816 
817     if (!j)
818       // The new filter coincides with range [i, end) of the existing filter.
819       return -(1 + i);
820 
821 try_next:;
822   }
823 
824   // Add the new filter.
825   int FilterID = -(1 + FilterIds.size());
826   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
827   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
828   FilterEnds.push_back(FilterIds.size());
829   FilterIds.push_back(0); // terminator
830   return FilterID;
831 }
832 
833 void MachineFunction::addCodeViewHeapAllocSite(MachineInstr *I, MDNode *MD) {
834   MCSymbol *BeginLabel = Ctx.createTempSymbol("heapallocsite", true);
835   MCSymbol *EndLabel = Ctx.createTempSymbol("heapallocsite", true);
836   I->setPreInstrSymbol(*this, BeginLabel);
837   I->setPostInstrSymbol(*this, EndLabel);
838 
839   DIType *DI = dyn_cast<DIType>(MD);
840   CodeViewHeapAllocSites.push_back(std::make_tuple(BeginLabel, EndLabel, DI));
841 }
842 
843 void MachineFunction::updateCallSiteInfo(const MachineInstr *Old,
844                                          const MachineInstr *New) {
845   if (!Target.Options.EnableDebugEntryValues || Old == New)
846     return;
847 
848   assert(Old->isCall() && (!New || New->isCall()) &&
849          "Call site info referes only to call instructions!");
850   CallSiteInfoMap::iterator CSIt = CallSitesInfo.find(Old);
851   if (CSIt == CallSitesInfo.end())
852     return;
853   CallSiteInfo CSInfo = std::move(CSIt->second);
854   CallSitesInfo.erase(CSIt);
855   if (New)
856     CallSitesInfo[New] = CSInfo;
857 }
858 
859 /// \}
860 
861 //===----------------------------------------------------------------------===//
862 //  MachineJumpTableInfo implementation
863 //===----------------------------------------------------------------------===//
864 
865 /// Return the size of each entry in the jump table.
866 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
867   // The size of a jump table entry is 4 bytes unless the entry is just the
868   // address of a block, in which case it is the pointer size.
869   switch (getEntryKind()) {
870   case MachineJumpTableInfo::EK_BlockAddress:
871     return TD.getPointerSize();
872   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
873     return 8;
874   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
875   case MachineJumpTableInfo::EK_LabelDifference32:
876   case MachineJumpTableInfo::EK_Custom32:
877     return 4;
878   case MachineJumpTableInfo::EK_Inline:
879     return 0;
880   }
881   llvm_unreachable("Unknown jump table encoding!");
882 }
883 
884 /// Return the alignment of each entry in the jump table.
885 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
886   // The alignment of a jump table entry is the alignment of int32 unless the
887   // entry is just the address of a block, in which case it is the pointer
888   // alignment.
889   switch (getEntryKind()) {
890   case MachineJumpTableInfo::EK_BlockAddress:
891     return TD.getPointerABIAlignment(0);
892   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
893     return TD.getABIIntegerTypeAlignment(64);
894   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
895   case MachineJumpTableInfo::EK_LabelDifference32:
896   case MachineJumpTableInfo::EK_Custom32:
897     return TD.getABIIntegerTypeAlignment(32);
898   case MachineJumpTableInfo::EK_Inline:
899     return 1;
900   }
901   llvm_unreachable("Unknown jump table encoding!");
902 }
903 
904 /// Create a new jump table entry in the jump table info.
905 unsigned MachineJumpTableInfo::createJumpTableIndex(
906                                const std::vector<MachineBasicBlock*> &DestBBs) {
907   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
908   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
909   return JumpTables.size()-1;
910 }
911 
912 /// If Old is the target of any jump tables, update the jump tables to branch
913 /// to New instead.
914 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
915                                                   MachineBasicBlock *New) {
916   assert(Old != New && "Not making a change?");
917   bool MadeChange = false;
918   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
919     ReplaceMBBInJumpTable(i, Old, New);
920   return MadeChange;
921 }
922 
923 /// If Old is a target of the jump tables, update the jump table to branch to
924 /// New instead.
925 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
926                                                  MachineBasicBlock *Old,
927                                                  MachineBasicBlock *New) {
928   assert(Old != New && "Not making a change?");
929   bool MadeChange = false;
930   MachineJumpTableEntry &JTE = JumpTables[Idx];
931   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
932     if (JTE.MBBs[j] == Old) {
933       JTE.MBBs[j] = New;
934       MadeChange = true;
935     }
936   return MadeChange;
937 }
938 
939 void MachineJumpTableInfo::print(raw_ostream &OS) const {
940   if (JumpTables.empty()) return;
941 
942   OS << "Jump Tables:\n";
943 
944   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
945     OS << printJumpTableEntryReference(i) << ':';
946     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
947       OS << ' ' << printMBBReference(*JumpTables[i].MBBs[j]);
948     if (i != e)
949       OS << '\n';
950   }
951 
952   OS << '\n';
953 }
954 
955 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
956 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
957 #endif
958 
959 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
960   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
961 }
962 
963 //===----------------------------------------------------------------------===//
964 //  MachineConstantPool implementation
965 //===----------------------------------------------------------------------===//
966 
967 void MachineConstantPoolValue::anchor() {}
968 
969 Type *MachineConstantPoolEntry::getType() const {
970   if (isMachineConstantPoolEntry())
971     return Val.MachineCPVal->getType();
972   return Val.ConstVal->getType();
973 }
974 
975 bool MachineConstantPoolEntry::needsRelocation() const {
976   if (isMachineConstantPoolEntry())
977     return true;
978   return Val.ConstVal->needsRelocation();
979 }
980 
981 SectionKind
982 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
983   if (needsRelocation())
984     return SectionKind::getReadOnlyWithRel();
985   switch (DL->getTypeAllocSize(getType())) {
986   case 4:
987     return SectionKind::getMergeableConst4();
988   case 8:
989     return SectionKind::getMergeableConst8();
990   case 16:
991     return SectionKind::getMergeableConst16();
992   case 32:
993     return SectionKind::getMergeableConst32();
994   default:
995     return SectionKind::getReadOnly();
996   }
997 }
998 
999 MachineConstantPool::~MachineConstantPool() {
1000   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
1001   // so keep track of which we've deleted to avoid double deletions.
1002   DenseSet<MachineConstantPoolValue*> Deleted;
1003   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1004     if (Constants[i].isMachineConstantPoolEntry()) {
1005       Deleted.insert(Constants[i].Val.MachineCPVal);
1006       delete Constants[i].Val.MachineCPVal;
1007     }
1008   for (DenseSet<MachineConstantPoolValue*>::iterator I =
1009        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
1010        I != E; ++I) {
1011     if (Deleted.count(*I) == 0)
1012       delete *I;
1013   }
1014 }
1015 
1016 /// Test whether the given two constants can be allocated the same constant pool
1017 /// entry.
1018 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
1019                                       const DataLayout &DL) {
1020   // Handle the trivial case quickly.
1021   if (A == B) return true;
1022 
1023   // If they have the same type but weren't the same constant, quickly
1024   // reject them.
1025   if (A->getType() == B->getType()) return false;
1026 
1027   // We can't handle structs or arrays.
1028   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
1029       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
1030     return false;
1031 
1032   // For now, only support constants with the same size.
1033   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
1034   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
1035     return false;
1036 
1037   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
1038 
1039   // Try constant folding a bitcast of both instructions to an integer.  If we
1040   // get two identical ConstantInt's, then we are good to share them.  We use
1041   // the constant folding APIs to do this so that we get the benefit of
1042   // DataLayout.
1043   if (isa<PointerType>(A->getType()))
1044     A = ConstantFoldCastOperand(Instruction::PtrToInt,
1045                                 const_cast<Constant *>(A), IntTy, DL);
1046   else if (A->getType() != IntTy)
1047     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
1048                                 IntTy, DL);
1049   if (isa<PointerType>(B->getType()))
1050     B = ConstantFoldCastOperand(Instruction::PtrToInt,
1051                                 const_cast<Constant *>(B), IntTy, DL);
1052   else if (B->getType() != IntTy)
1053     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
1054                                 IntTy, DL);
1055 
1056   return A == B;
1057 }
1058 
1059 /// Create a new entry in the constant pool or return an existing one.
1060 /// User must specify the log2 of the minimum required alignment for the object.
1061 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
1062                                                    unsigned Alignment) {
1063   assert(Alignment && "Alignment must be specified!");
1064   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1065 
1066   // Check to see if we already have this constant.
1067   //
1068   // FIXME, this could be made much more efficient for large constant pools.
1069   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1070     if (!Constants[i].isMachineConstantPoolEntry() &&
1071         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
1072       if ((unsigned)Constants[i].getAlignment() < Alignment)
1073         Constants[i].Alignment = Alignment;
1074       return i;
1075     }
1076 
1077   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
1078   return Constants.size()-1;
1079 }
1080 
1081 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
1082                                                    unsigned Alignment) {
1083   assert(Alignment && "Alignment must be specified!");
1084   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1085 
1086   // Check to see if we already have this constant.
1087   //
1088   // FIXME, this could be made much more efficient for large constant pools.
1089   int Idx = V->getExistingMachineCPValue(this, Alignment);
1090   if (Idx != -1) {
1091     MachineCPVsSharingEntries.insert(V);
1092     return (unsigned)Idx;
1093   }
1094 
1095   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1096   return Constants.size()-1;
1097 }
1098 
1099 void MachineConstantPool::print(raw_ostream &OS) const {
1100   if (Constants.empty()) return;
1101 
1102   OS << "Constant Pool:\n";
1103   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1104     OS << "  cp#" << i << ": ";
1105     if (Constants[i].isMachineConstantPoolEntry())
1106       Constants[i].Val.MachineCPVal->print(OS);
1107     else
1108       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1109     OS << ", align=" << Constants[i].getAlignment();
1110     OS << "\n";
1111   }
1112 }
1113 
1114 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1115 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1116 #endif
1117