1 //===-- llvm/CodeGen/MachineModuleInfo.cpp ----------------------*- C++ -*-===//
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 #include "llvm/CodeGen/MachineModuleInfo.h"
11 #include "llvm/ADT/PointerUnion.h"
12 #include "llvm/Analysis/LibCallSemantics.h"
13 #include "llvm/Analysis/ValueTracking.h"
14 #include "llvm/CodeGen/MachineFunction.h"
15 #include "llvm/CodeGen/MachineFunctionPass.h"
16 #include "llvm/CodeGen/Passes.h"
17 #include "llvm/CodeGen/WinEHFuncInfo.h"
18 #include "llvm/IR/Constants.h"
19 #include "llvm/IR/DerivedTypes.h"
20 #include "llvm/IR/GlobalVariable.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/MC/MCObjectFileInfo.h"
23 #include "llvm/MC/MCSymbol.h"
24 #include "llvm/Support/Dwarf.h"
25 #include "llvm/Support/ErrorHandling.h"
26 using namespace llvm;
27 using namespace llvm::dwarf;
28 
29 // Handle the Pass registration stuff necessary to use DataLayout's.
30 INITIALIZE_PASS(MachineModuleInfo, "machinemoduleinfo",
31                 "Machine Module Information", false, false)
32 char MachineModuleInfo::ID = 0;
33 
34 // Out of line virtual method.
~MachineModuleInfoImpl()35 MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
36 
37 namespace llvm {
38 class MMIAddrLabelMapCallbackPtr : CallbackVH {
39   MMIAddrLabelMap *Map;
40 public:
MMIAddrLabelMapCallbackPtr()41   MMIAddrLabelMapCallbackPtr() : Map(nullptr) {}
MMIAddrLabelMapCallbackPtr(Value * V)42   MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V), Map(nullptr) {}
43 
setPtr(BasicBlock * BB)44   void setPtr(BasicBlock *BB) {
45     ValueHandleBase::operator=(BB);
46   }
47 
setMap(MMIAddrLabelMap * map)48   void setMap(MMIAddrLabelMap *map) { Map = map; }
49 
50   void deleted() override;
51   void allUsesReplacedWith(Value *V2) override;
52 };
53 
54 class MMIAddrLabelMap {
55   MCContext &Context;
56   struct AddrLabelSymEntry {
57     /// Symbols - The symbols for the label.  This is a pointer union that is
58     /// either one symbol (the common case) or a list of symbols.
59     PointerUnion<MCSymbol *, std::vector<MCSymbol*>*> Symbols;
60 
61     Function *Fn;   // The containing function of the BasicBlock.
62     unsigned Index; // The index in BBCallbacks for the BasicBlock.
63   };
64 
65   DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
66 
67   /// BBCallbacks - Callbacks for the BasicBlock's that we have entries for.  We
68   /// use this so we get notified if a block is deleted or RAUWd.
69   std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
70 
71   /// DeletedAddrLabelsNeedingEmission - This is a per-function list of symbols
72   /// whose corresponding BasicBlock got deleted.  These symbols need to be
73   /// emitted at some point in the file, so AsmPrinter emits them after the
74   /// function body.
75   DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >
76     DeletedAddrLabelsNeedingEmission;
77 public:
78 
MMIAddrLabelMap(MCContext & context)79   MMIAddrLabelMap(MCContext &context) : Context(context) {}
~MMIAddrLabelMap()80   ~MMIAddrLabelMap() {
81     assert(DeletedAddrLabelsNeedingEmission.empty() &&
82            "Some labels for deleted blocks never got emitted");
83 
84     // Deallocate any of the 'list of symbols' case.
85     for (DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry>::iterator
86          I = AddrLabelSymbols.begin(), E = AddrLabelSymbols.end(); I != E; ++I)
87       if (I->second.Symbols.is<std::vector<MCSymbol*>*>())
88         delete I->second.Symbols.get<std::vector<MCSymbol*>*>();
89   }
90 
91   MCSymbol *getAddrLabelSymbol(BasicBlock *BB);
92   std::vector<MCSymbol*> getAddrLabelSymbolToEmit(BasicBlock *BB);
93 
94   void takeDeletedSymbolsForFunction(Function *F,
95                                      std::vector<MCSymbol*> &Result);
96 
97   void UpdateForDeletedBlock(BasicBlock *BB);
98   void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
99 };
100 }
101 
getAddrLabelSymbol(BasicBlock * BB)102 MCSymbol *MMIAddrLabelMap::getAddrLabelSymbol(BasicBlock *BB) {
103   assert(BB->hasAddressTaken() &&
104          "Shouldn't get label for block without address taken");
105   AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
106 
107   // If we already had an entry for this block, just return it.
108   if (!Entry.Symbols.isNull()) {
109     assert(BB->getParent() == Entry.Fn && "Parent changed");
110     if (Entry.Symbols.is<MCSymbol*>())
111       return Entry.Symbols.get<MCSymbol*>();
112     return (*Entry.Symbols.get<std::vector<MCSymbol*>*>())[0];
113   }
114 
115   // Otherwise, this is a new entry, create a new symbol for it and add an
116   // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
117   BBCallbacks.push_back(BB);
118   BBCallbacks.back().setMap(this);
119   Entry.Index = BBCallbacks.size()-1;
120   Entry.Fn = BB->getParent();
121   MCSymbol *Result = Context.CreateTempSymbol();
122   Entry.Symbols = Result;
123   return Result;
124 }
125 
126 std::vector<MCSymbol*>
getAddrLabelSymbolToEmit(BasicBlock * BB)127 MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
128   assert(BB->hasAddressTaken() &&
129          "Shouldn't get label for block without address taken");
130   AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
131 
132   std::vector<MCSymbol*> Result;
133 
134   // If we already had an entry for this block, just return it.
135   if (Entry.Symbols.isNull())
136     Result.push_back(getAddrLabelSymbol(BB));
137   else if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>())
138     Result.push_back(Sym);
139   else
140     Result = *Entry.Symbols.get<std::vector<MCSymbol*>*>();
141   return Result;
142 }
143 
144 
145 /// takeDeletedSymbolsForFunction - If we have any deleted symbols for F, return
146 /// them.
147 void MMIAddrLabelMap::
takeDeletedSymbolsForFunction(Function * F,std::vector<MCSymbol * > & Result)148 takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
149   DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >::iterator I =
150     DeletedAddrLabelsNeedingEmission.find(F);
151 
152   // If there are no entries for the function, just return.
153   if (I == DeletedAddrLabelsNeedingEmission.end()) return;
154 
155   // Otherwise, take the list.
156   std::swap(Result, I->second);
157   DeletedAddrLabelsNeedingEmission.erase(I);
158 }
159 
160 
UpdateForDeletedBlock(BasicBlock * BB)161 void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
162   // If the block got deleted, there is no need for the symbol.  If the symbol
163   // was already emitted, we can just forget about it, otherwise we need to
164   // queue it up for later emission when the function is output.
165   AddrLabelSymEntry Entry = AddrLabelSymbols[BB];
166   AddrLabelSymbols.erase(BB);
167   assert(!Entry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
168   BBCallbacks[Entry.Index] = nullptr;  // Clear the callback.
169 
170   assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
171          "Block/parent mismatch");
172 
173   // Handle both the single and the multiple symbols cases.
174   if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>()) {
175     if (Sym->isDefined())
176       return;
177 
178     // If the block is not yet defined, we need to emit it at the end of the
179     // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
180     // for the containing Function.  Since the block is being deleted, its
181     // parent may already be removed, we have to get the function from 'Entry'.
182     DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
183   } else {
184     std::vector<MCSymbol*> *Syms = Entry.Symbols.get<std::vector<MCSymbol*>*>();
185 
186     for (unsigned i = 0, e = Syms->size(); i != e; ++i) {
187       MCSymbol *Sym = (*Syms)[i];
188       if (Sym->isDefined()) continue;  // Ignore already emitted labels.
189 
190       // If the block is not yet defined, we need to emit it at the end of the
191       // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
192       // for the containing Function.  Since the block is being deleted, its
193       // parent may already be removed, we have to get the function from
194       // 'Entry'.
195       DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
196     }
197 
198     // The entry is deleted, free the memory associated with the symbol list.
199     delete Syms;
200   }
201 }
202 
UpdateForRAUWBlock(BasicBlock * Old,BasicBlock * New)203 void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
204   // Get the entry for the RAUW'd block and remove it from our map.
205   AddrLabelSymEntry OldEntry = AddrLabelSymbols[Old];
206   AddrLabelSymbols.erase(Old);
207   assert(!OldEntry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
208 
209   AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
210 
211   // If New is not address taken, just move our symbol over to it.
212   if (NewEntry.Symbols.isNull()) {
213     BBCallbacks[OldEntry.Index].setPtr(New);    // Update the callback.
214     NewEntry = OldEntry;     // Set New's entry.
215     return;
216   }
217 
218   BBCallbacks[OldEntry.Index] = nullptr;    // Update the callback.
219 
220   // Otherwise, we need to add the old symbol to the new block's set.  If it is
221   // just a single entry, upgrade it to a symbol list.
222   if (MCSymbol *PrevSym = NewEntry.Symbols.dyn_cast<MCSymbol*>()) {
223     std::vector<MCSymbol*> *SymList = new std::vector<MCSymbol*>();
224     SymList->push_back(PrevSym);
225     NewEntry.Symbols = SymList;
226   }
227 
228   std::vector<MCSymbol*> *SymList =
229     NewEntry.Symbols.get<std::vector<MCSymbol*>*>();
230 
231   // If the old entry was a single symbol, add it.
232   if (MCSymbol *Sym = OldEntry.Symbols.dyn_cast<MCSymbol*>()) {
233     SymList->push_back(Sym);
234     return;
235   }
236 
237   // Otherwise, concatenate the list.
238   std::vector<MCSymbol*> *Syms =OldEntry.Symbols.get<std::vector<MCSymbol*>*>();
239   SymList->insert(SymList->end(), Syms->begin(), Syms->end());
240   delete Syms;
241 }
242 
243 
deleted()244 void MMIAddrLabelMapCallbackPtr::deleted() {
245   Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
246 }
247 
allUsesReplacedWith(Value * V2)248 void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
249   Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
250 }
251 
252 
253 //===----------------------------------------------------------------------===//
254 
MachineModuleInfo(const MCAsmInfo & MAI,const MCRegisterInfo & MRI,const MCObjectFileInfo * MOFI)255 MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI,
256                                      const MCRegisterInfo &MRI,
257                                      const MCObjectFileInfo *MOFI)
258   : ImmutablePass(ID), Context(&MAI, &MRI, MOFI, nullptr, false) {
259   initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
260 }
261 
MachineModuleInfo()262 MachineModuleInfo::MachineModuleInfo()
263   : ImmutablePass(ID), Context(nullptr, nullptr, nullptr) {
264   llvm_unreachable("This MachineModuleInfo constructor should never be called, "
265                    "MMI should always be explicitly constructed by "
266                    "LLVMTargetMachine");
267 }
268 
~MachineModuleInfo()269 MachineModuleInfo::~MachineModuleInfo() {
270 }
271 
doInitialization(Module & M)272 bool MachineModuleInfo::doInitialization(Module &M) {
273 
274   ObjFileMMI = nullptr;
275   CurCallSite = 0;
276   CallsEHReturn = 0;
277   CallsUnwindInit = 0;
278   DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
279   // Always emit some info, by default "no personality" info.
280   Personalities.push_back(nullptr);
281   PersonalityTypeCache = EHPersonality::Unknown;
282   AddrLabelSymbols = nullptr;
283   TheModule = nullptr;
284 
285   return false;
286 }
287 
doFinalization(Module & M)288 bool MachineModuleInfo::doFinalization(Module &M) {
289 
290   Personalities.clear();
291 
292   delete AddrLabelSymbols;
293   AddrLabelSymbols = nullptr;
294 
295   Context.reset();
296 
297   delete ObjFileMMI;
298   ObjFileMMI = nullptr;
299 
300   return false;
301 }
302 
303 /// EndFunction - Discard function meta information.
304 ///
EndFunction()305 void MachineModuleInfo::EndFunction() {
306   // Clean up frame info.
307   FrameInstructions.clear();
308 
309   // Clean up exception info.
310   LandingPads.clear();
311   CallSiteMap.clear();
312   TypeInfos.clear();
313   FilterIds.clear();
314   FilterEnds.clear();
315   CallsEHReturn = 0;
316   CallsUnwindInit = 0;
317   VariableDbgInfos.clear();
318 }
319 
320 /// AnalyzeModule - Scan the module for global debug information.
321 ///
AnalyzeModule(const Module & M)322 void MachineModuleInfo::AnalyzeModule(const Module &M) {
323   // Insert functions in the llvm.used array (but not llvm.compiler.used) into
324   // UsedFunctions.
325   const GlobalVariable *GV = M.getGlobalVariable("llvm.used");
326   if (!GV || !GV->hasInitializer()) return;
327 
328   // Should be an array of 'i8*'.
329   const ConstantArray *InitList = cast<ConstantArray>(GV->getInitializer());
330 
331   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
332     if (const Function *F =
333           dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
334       UsedFunctions.insert(F);
335 }
336 
337 //===- Address of Block Management ----------------------------------------===//
338 
339 
340 /// getAddrLabelSymbol - Return the symbol to be used for the specified basic
341 /// block when its address is taken.  This cannot be its normal LBB label
342 /// because the block may be accessed outside its containing function.
getAddrLabelSymbol(const BasicBlock * BB)343 MCSymbol *MachineModuleInfo::getAddrLabelSymbol(const BasicBlock *BB) {
344   // Lazily create AddrLabelSymbols.
345   if (!AddrLabelSymbols)
346     AddrLabelSymbols = new MMIAddrLabelMap(Context);
347   return AddrLabelSymbols->getAddrLabelSymbol(const_cast<BasicBlock*>(BB));
348 }
349 
350 /// getAddrLabelSymbolToEmit - Return the symbol to be used for the specified
351 /// basic block when its address is taken.  If other blocks were RAUW'd to
352 /// this one, we may have to emit them as well, return the whole set.
353 std::vector<MCSymbol*> MachineModuleInfo::
getAddrLabelSymbolToEmit(const BasicBlock * BB)354 getAddrLabelSymbolToEmit(const BasicBlock *BB) {
355   // Lazily create AddrLabelSymbols.
356   if (!AddrLabelSymbols)
357     AddrLabelSymbols = new MMIAddrLabelMap(Context);
358  return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
359 }
360 
361 
362 /// takeDeletedSymbolsForFunction - If the specified function has had any
363 /// references to address-taken blocks generated, but the block got deleted,
364 /// return the symbol now so we can emit it.  This prevents emitting a
365 /// reference to a symbol that has no definition.
366 void MachineModuleInfo::
takeDeletedSymbolsForFunction(const Function * F,std::vector<MCSymbol * > & Result)367 takeDeletedSymbolsForFunction(const Function *F,
368                               std::vector<MCSymbol*> &Result) {
369   // If no blocks have had their addresses taken, we're done.
370   if (!AddrLabelSymbols) return;
371   return AddrLabelSymbols->
372      takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);
373 }
374 
375 //===- EH -----------------------------------------------------------------===//
376 
377 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
378 /// specified MachineBasicBlock.
getOrCreateLandingPadInfo(MachineBasicBlock * LandingPad)379 LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
380     (MachineBasicBlock *LandingPad) {
381   unsigned N = LandingPads.size();
382   for (unsigned i = 0; i < N; ++i) {
383     LandingPadInfo &LP = LandingPads[i];
384     if (LP.LandingPadBlock == LandingPad)
385       return LP;
386   }
387 
388   LandingPads.push_back(LandingPadInfo(LandingPad));
389   return LandingPads[N];
390 }
391 
392 /// addInvoke - Provide the begin and end labels of an invoke style call and
393 /// associate it with a try landing pad block.
addInvoke(MachineBasicBlock * LandingPad,MCSymbol * BeginLabel,MCSymbol * EndLabel)394 void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
395                                   MCSymbol *BeginLabel, MCSymbol *EndLabel) {
396   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
397   LP.BeginLabels.push_back(BeginLabel);
398   LP.EndLabels.push_back(EndLabel);
399 }
400 
401 /// addLandingPad - Provide the label of a try LandingPad block.
402 ///
addLandingPad(MachineBasicBlock * LandingPad)403 MCSymbol *MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
404   MCSymbol *LandingPadLabel = Context.CreateTempSymbol();
405   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
406   LP.LandingPadLabel = LandingPadLabel;
407   return LandingPadLabel;
408 }
409 
410 /// addPersonality - Provide the personality function for the exception
411 /// information.
addPersonality(MachineBasicBlock * LandingPad,const Function * Personality)412 void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
413                                        const Function *Personality) {
414   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
415   LP.Personality = Personality;
416 
417   for (unsigned i = 0; i < Personalities.size(); ++i)
418     if (Personalities[i] == Personality)
419       return;
420 
421   // If this is the first personality we're adding go
422   // ahead and add it at the beginning.
423   if (!Personalities[0])
424     Personalities[0] = Personality;
425   else
426     Personalities.push_back(Personality);
427 }
428 
addWinEHState(MachineBasicBlock * LandingPad,int State)429 void MachineModuleInfo::addWinEHState(MachineBasicBlock *LandingPad,
430                                       int State) {
431   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
432   LP.WinEHState = State;
433 }
434 
435 /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
436 ///
437 void MachineModuleInfo::
addCatchTypeInfo(MachineBasicBlock * LandingPad,ArrayRef<const GlobalValue * > TyInfo)438 addCatchTypeInfo(MachineBasicBlock *LandingPad,
439                  ArrayRef<const GlobalValue *> TyInfo) {
440   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
441   for (unsigned N = TyInfo.size(); N; --N)
442     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
443 }
444 
445 /// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
446 ///
447 void MachineModuleInfo::
addFilterTypeInfo(MachineBasicBlock * LandingPad,ArrayRef<const GlobalValue * > TyInfo)448 addFilterTypeInfo(MachineBasicBlock *LandingPad,
449                   ArrayRef<const GlobalValue *> TyInfo) {
450   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
451   std::vector<unsigned> IdsInFilter(TyInfo.size());
452   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
453     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
454   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
455 }
456 
457 /// addCleanup - Add a cleanup action for a landing pad.
458 ///
addCleanup(MachineBasicBlock * LandingPad)459 void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
460   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
461   LP.TypeIds.push_back(0);
462 }
463 
464 MCSymbol *
addClauseForLandingPad(MachineBasicBlock * LandingPad)465 MachineModuleInfo::addClauseForLandingPad(MachineBasicBlock *LandingPad) {
466   MCSymbol *ClauseLabel = Context.CreateTempSymbol();
467   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
468   LP.ClauseLabels.push_back(ClauseLabel);
469   return ClauseLabel;
470 }
471 
472 /// TidyLandingPads - Remap landing pad labels and remove any deleted landing
473 /// pads.
TidyLandingPads(DenseMap<MCSymbol *,uintptr_t> * LPMap)474 void MachineModuleInfo::TidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
475   for (unsigned i = 0; i != LandingPads.size(); ) {
476     LandingPadInfo &LandingPad = LandingPads[i];
477     if (LandingPad.LandingPadLabel &&
478         !LandingPad.LandingPadLabel->isDefined() &&
479         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
480       LandingPad.LandingPadLabel = nullptr;
481 
482     // Special case: we *should* emit LPs with null LP MBB. This indicates
483     // "nounwind" case.
484     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
485       LandingPads.erase(LandingPads.begin() + i);
486       continue;
487     }
488 
489     for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
490       MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
491       MCSymbol *EndLabel = LandingPad.EndLabels[j];
492       if ((BeginLabel->isDefined() ||
493            (LPMap && (*LPMap)[BeginLabel] != 0)) &&
494           (EndLabel->isDefined() ||
495            (LPMap && (*LPMap)[EndLabel] != 0))) continue;
496 
497       LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
498       LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
499       --j, --e;
500     }
501 
502     // Remove landing pads with no try-ranges.
503     if (LandingPads[i].BeginLabels.empty()) {
504       LandingPads.erase(LandingPads.begin() + i);
505       continue;
506     }
507 
508     // If there is no landing pad, ensure that the list of typeids is empty.
509     // If the only typeid is a cleanup, this is the same as having no typeids.
510     if (!LandingPad.LandingPadBlock ||
511         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
512       LandingPad.TypeIds.clear();
513     ++i;
514   }
515 }
516 
517 /// setCallSiteLandingPad - Map the landing pad's EH symbol to the call site
518 /// indexes.
setCallSiteLandingPad(MCSymbol * Sym,ArrayRef<unsigned> Sites)519 void MachineModuleInfo::setCallSiteLandingPad(MCSymbol *Sym,
520                                               ArrayRef<unsigned> Sites) {
521   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
522 }
523 
524 /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
525 /// function wide.
getTypeIDFor(const GlobalValue * TI)526 unsigned MachineModuleInfo::getTypeIDFor(const GlobalValue *TI) {
527   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
528     if (TypeInfos[i] == TI) return i + 1;
529 
530   TypeInfos.push_back(TI);
531   return TypeInfos.size();
532 }
533 
534 /// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
535 /// function wide.
getFilterIDFor(std::vector<unsigned> & TyIds)536 int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
537   // If the new filter coincides with the tail of an existing filter, then
538   // re-use the existing filter.  Folding filters more than this requires
539   // re-ordering filters and/or their elements - probably not worth it.
540   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
541        E = FilterEnds.end(); I != E; ++I) {
542     unsigned i = *I, j = TyIds.size();
543 
544     while (i && j)
545       if (FilterIds[--i] != TyIds[--j])
546         goto try_next;
547 
548     if (!j)
549       // The new filter coincides with range [i, end) of the existing filter.
550       return -(1 + i);
551 
552 try_next:;
553   }
554 
555   // Add the new filter.
556   int FilterID = -(1 + FilterIds.size());
557   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
558   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
559   FilterEnds.push_back(FilterIds.size());
560   FilterIds.push_back(0); // terminator
561   return FilterID;
562 }
563 
564 /// getPersonality - Return the personality function for the current function.
getPersonality() const565 const Function *MachineModuleInfo::getPersonality() const {
566   for (const LandingPadInfo &LPI : LandingPads)
567     if (LPI.Personality)
568       return LPI.Personality;
569   return nullptr;
570 }
571 
getPersonalityType()572 EHPersonality MachineModuleInfo::getPersonalityType() {
573   if (PersonalityTypeCache == EHPersonality::Unknown) {
574     if (const Function *F = getPersonality())
575       PersonalityTypeCache = classifyEHPersonality(F);
576   }
577   return PersonalityTypeCache;
578 }
579 
580 /// getPersonalityIndex - Return unique index for current personality
581 /// function. NULL/first personality function should always get zero index.
getPersonalityIndex() const582 unsigned MachineModuleInfo::getPersonalityIndex() const {
583   const Function* Personality = nullptr;
584 
585   // Scan landing pads. If there is at least one non-NULL personality - use it.
586   for (unsigned i = 0, e = LandingPads.size(); i != e; ++i)
587     if (LandingPads[i].Personality) {
588       Personality = LandingPads[i].Personality;
589       break;
590     }
591 
592   for (unsigned i = 0, e = Personalities.size(); i < e; ++i) {
593     if (Personalities[i] == Personality)
594       return i;
595   }
596 
597   // This will happen if the current personality function is
598   // in the zero index.
599   return 0;
600 }
601 
getWinEHParent(const Function * F) const602 const Function *MachineModuleInfo::getWinEHParent(const Function *F) const {
603   StringRef WinEHParentName =
604       F->getFnAttribute("wineh-parent").getValueAsString();
605   if (WinEHParentName.empty() || WinEHParentName == F->getName())
606     return F;
607   return F->getParent()->getFunction(WinEHParentName);
608 }
609 
getWinEHFuncInfo(const Function * F)610 WinEHFuncInfo &MachineModuleInfo::getWinEHFuncInfo(const Function *F) {
611   auto &Ptr = FuncInfoMap[getWinEHParent(F)];
612   if (!Ptr)
613     Ptr.reset(new WinEHFuncInfo);
614   return *Ptr;
615 }
616