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/ADT/TinyPtrVector.h"
13#include "llvm/Analysis/EHPersonalities.h"
14#include "llvm/Analysis/ValueTracking.h"
15#include "llvm/CodeGen/MachineFunction.h"
16#include "llvm/CodeGen/MachineFunctionPass.h"
17#include "llvm/CodeGen/Passes.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"
26using namespace llvm;
27using namespace llvm::dwarf;
28
29// Handle the Pass registration stuff necessary to use DataLayout's.
30INITIALIZE_PASS(MachineModuleInfo, "machinemoduleinfo",
31                "Machine Module Information", false, false)
32char MachineModuleInfo::ID = 0;
33
34// Out of line virtual method.
35MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
36
37namespace llvm {
38class MMIAddrLabelMapCallbackPtr final : CallbackVH {
39  MMIAddrLabelMap *Map;
40public:
41  MMIAddrLabelMapCallbackPtr() : Map(nullptr) {}
42  MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V), Map(nullptr) {}
43
44  void setPtr(BasicBlock *BB) {
45    ValueHandleBase::operator=(BB);
46  }
47
48  void setMap(MMIAddrLabelMap *map) { Map = map; }
49
50  void deleted() override;
51  void allUsesReplacedWith(Value *V2) override;
52};
53
54class MMIAddrLabelMap {
55  MCContext &Context;
56  struct AddrLabelSymEntry {
57    /// Symbols - The symbols for the label.
58    TinyPtrVector<MCSymbol *> Symbols;
59
60    Function *Fn;   // The containing function of the BasicBlock.
61    unsigned Index; // The index in BBCallbacks for the BasicBlock.
62  };
63
64  DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
65
66  /// BBCallbacks - Callbacks for the BasicBlock's that we have entries for.  We
67  /// use this so we get notified if a block is deleted or RAUWd.
68  std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
69
70  /// DeletedAddrLabelsNeedingEmission - This is a per-function list of symbols
71  /// whose corresponding BasicBlock got deleted.  These symbols need to be
72  /// emitted at some point in the file, so AsmPrinter emits them after the
73  /// function body.
74  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >
75    DeletedAddrLabelsNeedingEmission;
76public:
77
78  MMIAddrLabelMap(MCContext &context) : Context(context) {}
79  ~MMIAddrLabelMap() {
80    assert(DeletedAddrLabelsNeedingEmission.empty() &&
81           "Some labels for deleted blocks never got emitted");
82  }
83
84  ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(BasicBlock *BB);
85
86  void takeDeletedSymbolsForFunction(Function *F,
87                                     std::vector<MCSymbol*> &Result);
88
89  void UpdateForDeletedBlock(BasicBlock *BB);
90  void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
91};
92}
93
94ArrayRef<MCSymbol *> MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
95  assert(BB->hasAddressTaken() &&
96         "Shouldn't get label for block without address taken");
97  AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
98
99  // If we already had an entry for this block, just return it.
100  if (!Entry.Symbols.empty()) {
101    assert(BB->getParent() == Entry.Fn && "Parent changed");
102    return Entry.Symbols;
103  }
104
105  // Otherwise, this is a new entry, create a new symbol for it and add an
106  // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
107  BBCallbacks.emplace_back(BB);
108  BBCallbacks.back().setMap(this);
109  Entry.Index = BBCallbacks.size() - 1;
110  Entry.Fn = BB->getParent();
111  Entry.Symbols.push_back(Context.createTempSymbol());
112  return Entry.Symbols;
113}
114
115/// takeDeletedSymbolsForFunction - If we have any deleted symbols for F, return
116/// them.
117void MMIAddrLabelMap::
118takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
119  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >::iterator I =
120    DeletedAddrLabelsNeedingEmission.find(F);
121
122  // If there are no entries for the function, just return.
123  if (I == DeletedAddrLabelsNeedingEmission.end()) return;
124
125  // Otherwise, take the list.
126  std::swap(Result, I->second);
127  DeletedAddrLabelsNeedingEmission.erase(I);
128}
129
130
131void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
132  // If the block got deleted, there is no need for the symbol.  If the symbol
133  // was already emitted, we can just forget about it, otherwise we need to
134  // queue it up for later emission when the function is output.
135  AddrLabelSymEntry Entry = std::move(AddrLabelSymbols[BB]);
136  AddrLabelSymbols.erase(BB);
137  assert(!Entry.Symbols.empty() && "Didn't have a symbol, why a callback?");
138  BBCallbacks[Entry.Index] = nullptr;  // Clear the callback.
139
140  assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
141         "Block/parent mismatch");
142
143  for (MCSymbol *Sym : Entry.Symbols) {
144    if (Sym->isDefined())
145      return;
146
147    // If the block is not yet defined, we need to emit it at the end of the
148    // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
149    // for the containing Function.  Since the block is being deleted, its
150    // parent may already be removed, we have to get the function from 'Entry'.
151    DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
152  }
153}
154
155void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
156  // Get the entry for the RAUW'd block and remove it from our map.
157  AddrLabelSymEntry OldEntry = std::move(AddrLabelSymbols[Old]);
158  AddrLabelSymbols.erase(Old);
159  assert(!OldEntry.Symbols.empty() && "Didn't have a symbol, why a callback?");
160
161  AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
162
163  // If New is not address taken, just move our symbol over to it.
164  if (NewEntry.Symbols.empty()) {
165    BBCallbacks[OldEntry.Index].setPtr(New);    // Update the callback.
166    NewEntry = std::move(OldEntry);             // Set New's entry.
167    return;
168  }
169
170  BBCallbacks[OldEntry.Index] = nullptr;    // Update the callback.
171
172  // Otherwise, we need to add the old symbols to the new block's set.
173  NewEntry.Symbols.insert(NewEntry.Symbols.end(), OldEntry.Symbols.begin(),
174                          OldEntry.Symbols.end());
175}
176
177
178void MMIAddrLabelMapCallbackPtr::deleted() {
179  Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
180}
181
182void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
183  Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
184}
185
186
187//===----------------------------------------------------------------------===//
188
189MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI,
190                                     const MCRegisterInfo &MRI,
191                                     const MCObjectFileInfo *MOFI)
192  : ImmutablePass(ID), Context(&MAI, &MRI, MOFI, nullptr, false) {
193  initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
194}
195
196MachineModuleInfo::MachineModuleInfo()
197  : ImmutablePass(ID), Context(nullptr, nullptr, nullptr) {
198  llvm_unreachable("This MachineModuleInfo constructor should never be called, "
199                   "MMI should always be explicitly constructed by "
200                   "LLVMTargetMachine");
201}
202
203MachineModuleInfo::~MachineModuleInfo() {
204}
205
206bool MachineModuleInfo::doInitialization(Module &M) {
207
208  ObjFileMMI = nullptr;
209  CurCallSite = 0;
210  CallsEHReturn = false;
211  CallsUnwindInit = false;
212  HasEHFunclets = false;
213  DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
214  PersonalityTypeCache = EHPersonality::Unknown;
215  AddrLabelSymbols = nullptr;
216  TheModule = nullptr;
217
218  return false;
219}
220
221bool MachineModuleInfo::doFinalization(Module &M) {
222
223  Personalities.clear();
224
225  delete AddrLabelSymbols;
226  AddrLabelSymbols = nullptr;
227
228  Context.reset();
229
230  delete ObjFileMMI;
231  ObjFileMMI = nullptr;
232
233  return false;
234}
235
236/// EndFunction - Discard function meta information.
237///
238void MachineModuleInfo::EndFunction() {
239  // Clean up frame info.
240  FrameInstructions.clear();
241
242  // Clean up exception info.
243  LandingPads.clear();
244  PersonalityTypeCache = EHPersonality::Unknown;
245  CallSiteMap.clear();
246  TypeInfos.clear();
247  FilterIds.clear();
248  FilterEnds.clear();
249  CallsEHReturn = false;
250  CallsUnwindInit = false;
251  HasEHFunclets = false;
252  VariableDbgInfos.clear();
253}
254
255//===- Address of Block Management ----------------------------------------===//
256
257/// getAddrLabelSymbolToEmit - Return the symbol to be used for the specified
258/// basic block when its address is taken.  If other blocks were RAUW'd to
259/// this one, we may have to emit them as well, return the whole set.
260ArrayRef<MCSymbol *>
261MachineModuleInfo::getAddrLabelSymbolToEmit(const BasicBlock *BB) {
262  // Lazily create AddrLabelSymbols.
263  if (!AddrLabelSymbols)
264    AddrLabelSymbols = new MMIAddrLabelMap(Context);
265 return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
266}
267
268
269/// takeDeletedSymbolsForFunction - If the specified function has had any
270/// references to address-taken blocks generated, but the block got deleted,
271/// return the symbol now so we can emit it.  This prevents emitting a
272/// reference to a symbol that has no definition.
273void MachineModuleInfo::
274takeDeletedSymbolsForFunction(const Function *F,
275                              std::vector<MCSymbol*> &Result) {
276  // If no blocks have had their addresses taken, we're done.
277  if (!AddrLabelSymbols) return;
278  return AddrLabelSymbols->
279     takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);
280}
281
282//===- EH -----------------------------------------------------------------===//
283
284/// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
285/// specified MachineBasicBlock.
286LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
287    (MachineBasicBlock *LandingPad) {
288  unsigned N = LandingPads.size();
289  for (unsigned i = 0; i < N; ++i) {
290    LandingPadInfo &LP = LandingPads[i];
291    if (LP.LandingPadBlock == LandingPad)
292      return LP;
293  }
294
295  LandingPads.push_back(LandingPadInfo(LandingPad));
296  return LandingPads[N];
297}
298
299/// addInvoke - Provide the begin and end labels of an invoke style call and
300/// associate it with a try landing pad block.
301void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
302                                  MCSymbol *BeginLabel, MCSymbol *EndLabel) {
303  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
304  LP.BeginLabels.push_back(BeginLabel);
305  LP.EndLabels.push_back(EndLabel);
306}
307
308/// addLandingPad - Provide the label of a try LandingPad block.
309///
310MCSymbol *MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
311  MCSymbol *LandingPadLabel = Context.createTempSymbol();
312  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
313  LP.LandingPadLabel = LandingPadLabel;
314  return LandingPadLabel;
315}
316
317void MachineModuleInfo::addPersonality(const Function *Personality) {
318  for (unsigned i = 0; i < Personalities.size(); ++i)
319    if (Personalities[i] == Personality)
320      return;
321  Personalities.push_back(Personality);
322}
323
324/// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
325///
326void MachineModuleInfo::
327addCatchTypeInfo(MachineBasicBlock *LandingPad,
328                 ArrayRef<const GlobalValue *> TyInfo) {
329  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
330  for (unsigned N = TyInfo.size(); N; --N)
331    LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
332}
333
334/// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
335///
336void MachineModuleInfo::
337addFilterTypeInfo(MachineBasicBlock *LandingPad,
338                  ArrayRef<const GlobalValue *> TyInfo) {
339  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
340  std::vector<unsigned> IdsInFilter(TyInfo.size());
341  for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
342    IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
343  LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
344}
345
346/// addCleanup - Add a cleanup action for a landing pad.
347///
348void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
349  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
350  LP.TypeIds.push_back(0);
351}
352
353void MachineModuleInfo::addSEHCatchHandler(MachineBasicBlock *LandingPad,
354                                           const Function *Filter,
355                                           const BlockAddress *RecoverBA) {
356  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
357  SEHHandler Handler;
358  Handler.FilterOrFinally = Filter;
359  Handler.RecoverBA = RecoverBA;
360  LP.SEHHandlers.push_back(Handler);
361}
362
363void MachineModuleInfo::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
364                                             const Function *Cleanup) {
365  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
366  SEHHandler Handler;
367  Handler.FilterOrFinally = Cleanup;
368  Handler.RecoverBA = nullptr;
369  LP.SEHHandlers.push_back(Handler);
370}
371
372/// TidyLandingPads - Remap landing pad labels and remove any deleted landing
373/// pads.
374void MachineModuleInfo::TidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
375  for (unsigned i = 0; i != LandingPads.size(); ) {
376    LandingPadInfo &LandingPad = LandingPads[i];
377    if (LandingPad.LandingPadLabel &&
378        !LandingPad.LandingPadLabel->isDefined() &&
379        (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
380      LandingPad.LandingPadLabel = nullptr;
381
382    // Special case: we *should* emit LPs with null LP MBB. This indicates
383    // "nounwind" case.
384    if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
385      LandingPads.erase(LandingPads.begin() + i);
386      continue;
387    }
388
389    for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
390      MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
391      MCSymbol *EndLabel = LandingPad.EndLabels[j];
392      if ((BeginLabel->isDefined() ||
393           (LPMap && (*LPMap)[BeginLabel] != 0)) &&
394          (EndLabel->isDefined() ||
395           (LPMap && (*LPMap)[EndLabel] != 0))) continue;
396
397      LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
398      LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
399      --j, --e;
400    }
401
402    // Remove landing pads with no try-ranges.
403    if (LandingPads[i].BeginLabels.empty()) {
404      LandingPads.erase(LandingPads.begin() + i);
405      continue;
406    }
407
408    // If there is no landing pad, ensure that the list of typeids is empty.
409    // If the only typeid is a cleanup, this is the same as having no typeids.
410    if (!LandingPad.LandingPadBlock ||
411        (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
412      LandingPad.TypeIds.clear();
413    ++i;
414  }
415}
416
417/// setCallSiteLandingPad - Map the landing pad's EH symbol to the call site
418/// indexes.
419void MachineModuleInfo::setCallSiteLandingPad(MCSymbol *Sym,
420                                              ArrayRef<unsigned> Sites) {
421  LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
422}
423
424/// getTypeIDFor - Return the type id for the specified typeinfo.  This is
425/// function wide.
426unsigned MachineModuleInfo::getTypeIDFor(const GlobalValue *TI) {
427  for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
428    if (TypeInfos[i] == TI) return i + 1;
429
430  TypeInfos.push_back(TI);
431  return TypeInfos.size();
432}
433
434/// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
435/// function wide.
436int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
437  // If the new filter coincides with the tail of an existing filter, then
438  // re-use the existing filter.  Folding filters more than this requires
439  // re-ordering filters and/or their elements - probably not worth it.
440  for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
441       E = FilterEnds.end(); I != E; ++I) {
442    unsigned i = *I, j = TyIds.size();
443
444    while (i && j)
445      if (FilterIds[--i] != TyIds[--j])
446        goto try_next;
447
448    if (!j)
449      // The new filter coincides with range [i, end) of the existing filter.
450      return -(1 + i);
451
452try_next:;
453  }
454
455  // Add the new filter.
456  int FilterID = -(1 + FilterIds.size());
457  FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
458  FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
459  FilterEnds.push_back(FilterIds.size());
460  FilterIds.push_back(0); // terminator
461  return FilterID;
462}
463