1//===- Metadata.cpp - Implement Metadata classes --------------------------===//
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// This file implements the Metadata classes.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/IR/Metadata.h"
15#include "LLVMContextImpl.h"
16#include "MetadataImpl.h"
17#include "SymbolTableListTraitsImpl.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SmallSet.h"
21#include "llvm/ADT/SmallString.h"
22#include "llvm/ADT/StringMap.h"
23#include "llvm/IR/ConstantRange.h"
24#include "llvm/IR/DebugInfoMetadata.h"
25#include "llvm/IR/Instruction.h"
26#include "llvm/IR/LLVMContext.h"
27#include "llvm/IR/Module.h"
28#include "llvm/IR/ValueHandle.h"
29
30using namespace llvm;
31
32MetadataAsValue::MetadataAsValue(Type *Ty, Metadata *MD)
33    : Value(Ty, MetadataAsValueVal), MD(MD) {
34  track();
35}
36
37MetadataAsValue::~MetadataAsValue() {
38  getType()->getContext().pImpl->MetadataAsValues.erase(MD);
39  untrack();
40}
41
42/// \brief Canonicalize metadata arguments to intrinsics.
43///
44/// To support bitcode upgrades (and assembly semantic sugar) for \a
45/// MetadataAsValue, we need to canonicalize certain metadata.
46///
47///   - nullptr is replaced by an empty MDNode.
48///   - An MDNode with a single null operand is replaced by an empty MDNode.
49///   - An MDNode whose only operand is a \a ConstantAsMetadata gets skipped.
50///
51/// This maintains readability of bitcode from when metadata was a type of
52/// value, and these bridges were unnecessary.
53static Metadata *canonicalizeMetadataForValue(LLVMContext &Context,
54                                              Metadata *MD) {
55  if (!MD)
56    // !{}
57    return MDNode::get(Context, None);
58
59  // Return early if this isn't a single-operand MDNode.
60  auto *N = dyn_cast<MDNode>(MD);
61  if (!N || N->getNumOperands() != 1)
62    return MD;
63
64  if (!N->getOperand(0))
65    // !{}
66    return MDNode::get(Context, None);
67
68  if (auto *C = dyn_cast<ConstantAsMetadata>(N->getOperand(0)))
69    // Look through the MDNode.
70    return C;
71
72  return MD;
73}
74
75MetadataAsValue *MetadataAsValue::get(LLVMContext &Context, Metadata *MD) {
76  MD = canonicalizeMetadataForValue(Context, MD);
77  auto *&Entry = Context.pImpl->MetadataAsValues[MD];
78  if (!Entry)
79    Entry = new MetadataAsValue(Type::getMetadataTy(Context), MD);
80  return Entry;
81}
82
83MetadataAsValue *MetadataAsValue::getIfExists(LLVMContext &Context,
84                                              Metadata *MD) {
85  MD = canonicalizeMetadataForValue(Context, MD);
86  auto &Store = Context.pImpl->MetadataAsValues;
87  return Store.lookup(MD);
88}
89
90void MetadataAsValue::handleChangedMetadata(Metadata *MD) {
91  LLVMContext &Context = getContext();
92  MD = canonicalizeMetadataForValue(Context, MD);
93  auto &Store = Context.pImpl->MetadataAsValues;
94
95  // Stop tracking the old metadata.
96  Store.erase(this->MD);
97  untrack();
98  this->MD = nullptr;
99
100  // Start tracking MD, or RAUW if necessary.
101  auto *&Entry = Store[MD];
102  if (Entry) {
103    replaceAllUsesWith(Entry);
104    delete this;
105    return;
106  }
107
108  this->MD = MD;
109  track();
110  Entry = this;
111}
112
113void MetadataAsValue::track() {
114  if (MD)
115    MetadataTracking::track(&MD, *MD, *this);
116}
117
118void MetadataAsValue::untrack() {
119  if (MD)
120    MetadataTracking::untrack(MD);
121}
122
123void ReplaceableMetadataImpl::addRef(void *Ref, OwnerTy Owner) {
124  bool WasInserted =
125      UseMap.insert(std::make_pair(Ref, std::make_pair(Owner, NextIndex)))
126          .second;
127  (void)WasInserted;
128  assert(WasInserted && "Expected to add a reference");
129
130  ++NextIndex;
131  assert(NextIndex != 0 && "Unexpected overflow");
132}
133
134void ReplaceableMetadataImpl::dropRef(void *Ref) {
135  bool WasErased = UseMap.erase(Ref);
136  (void)WasErased;
137  assert(WasErased && "Expected to drop a reference");
138}
139
140void ReplaceableMetadataImpl::moveRef(void *Ref, void *New,
141                                      const Metadata &MD) {
142  auto I = UseMap.find(Ref);
143  assert(I != UseMap.end() && "Expected to move a reference");
144  auto OwnerAndIndex = I->second;
145  UseMap.erase(I);
146  bool WasInserted = UseMap.insert(std::make_pair(New, OwnerAndIndex)).second;
147  (void)WasInserted;
148  assert(WasInserted && "Expected to add a reference");
149
150  // Check that the references are direct if there's no owner.
151  (void)MD;
152  assert((OwnerAndIndex.first || *static_cast<Metadata **>(Ref) == &MD) &&
153         "Reference without owner must be direct");
154  assert((OwnerAndIndex.first || *static_cast<Metadata **>(New) == &MD) &&
155         "Reference without owner must be direct");
156}
157
158void ReplaceableMetadataImpl::replaceAllUsesWith(Metadata *MD) {
159  assert(!(MD && isa<MDNode>(MD) && cast<MDNode>(MD)->isTemporary()) &&
160         "Expected non-temp node");
161
162  if (UseMap.empty())
163    return;
164
165  // Copy out uses since UseMap will get touched below.
166  typedef std::pair<void *, std::pair<OwnerTy, uint64_t>> UseTy;
167  SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
168  std::sort(Uses.begin(), Uses.end(), [](const UseTy &L, const UseTy &R) {
169    return L.second.second < R.second.second;
170  });
171  for (const auto &Pair : Uses) {
172    // Check that this Ref hasn't disappeared after RAUW (when updating a
173    // previous Ref).
174    if (!UseMap.count(Pair.first))
175      continue;
176
177    OwnerTy Owner = Pair.second.first;
178    if (!Owner) {
179      // Update unowned tracking references directly.
180      Metadata *&Ref = *static_cast<Metadata **>(Pair.first);
181      Ref = MD;
182      if (MD)
183        MetadataTracking::track(Ref);
184      UseMap.erase(Pair.first);
185      continue;
186    }
187
188    // Check for MetadataAsValue.
189    if (Owner.is<MetadataAsValue *>()) {
190      Owner.get<MetadataAsValue *>()->handleChangedMetadata(MD);
191      continue;
192    }
193
194    // There's a Metadata owner -- dispatch.
195    Metadata *OwnerMD = Owner.get<Metadata *>();
196    switch (OwnerMD->getMetadataID()) {
197#define HANDLE_METADATA_LEAF(CLASS)                                            \
198  case Metadata::CLASS##Kind:                                                  \
199    cast<CLASS>(OwnerMD)->handleChangedOperand(Pair.first, MD);                \
200    continue;
201#include "llvm/IR/Metadata.def"
202    default:
203      llvm_unreachable("Invalid metadata subclass");
204    }
205  }
206  assert(UseMap.empty() && "Expected all uses to be replaced");
207}
208
209void ReplaceableMetadataImpl::resolveAllUses(bool ResolveUsers) {
210  if (UseMap.empty())
211    return;
212
213  if (!ResolveUsers) {
214    UseMap.clear();
215    return;
216  }
217
218  // Copy out uses since UseMap could get touched below.
219  typedef std::pair<void *, std::pair<OwnerTy, uint64_t>> UseTy;
220  SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
221  std::sort(Uses.begin(), Uses.end(), [](const UseTy &L, const UseTy &R) {
222    return L.second.second < R.second.second;
223  });
224  UseMap.clear();
225  for (const auto &Pair : Uses) {
226    auto Owner = Pair.second.first;
227    if (!Owner)
228      continue;
229    if (Owner.is<MetadataAsValue *>())
230      continue;
231
232    // Resolve MDNodes that point at this.
233    auto *OwnerMD = dyn_cast<MDNode>(Owner.get<Metadata *>());
234    if (!OwnerMD)
235      continue;
236    if (OwnerMD->isResolved())
237      continue;
238    OwnerMD->decrementUnresolvedOperandCount();
239  }
240}
241
242static Function *getLocalFunction(Value *V) {
243  assert(V && "Expected value");
244  if (auto *A = dyn_cast<Argument>(V))
245    return A->getParent();
246  if (BasicBlock *BB = cast<Instruction>(V)->getParent())
247    return BB->getParent();
248  return nullptr;
249}
250
251ValueAsMetadata *ValueAsMetadata::get(Value *V) {
252  assert(V && "Unexpected null Value");
253
254  auto &Context = V->getContext();
255  auto *&Entry = Context.pImpl->ValuesAsMetadata[V];
256  if (!Entry) {
257    assert((isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) &&
258           "Expected constant or function-local value");
259    assert(!V->IsUsedByMD &&
260           "Expected this to be the only metadata use");
261    V->IsUsedByMD = true;
262    if (auto *C = dyn_cast<Constant>(V))
263      Entry = new ConstantAsMetadata(C);
264    else
265      Entry = new LocalAsMetadata(V);
266  }
267
268  return Entry;
269}
270
271ValueAsMetadata *ValueAsMetadata::getIfExists(Value *V) {
272  assert(V && "Unexpected null Value");
273  return V->getContext().pImpl->ValuesAsMetadata.lookup(V);
274}
275
276void ValueAsMetadata::handleDeletion(Value *V) {
277  assert(V && "Expected valid value");
278
279  auto &Store = V->getType()->getContext().pImpl->ValuesAsMetadata;
280  auto I = Store.find(V);
281  if (I == Store.end())
282    return;
283
284  // Remove old entry from the map.
285  ValueAsMetadata *MD = I->second;
286  assert(MD && "Expected valid metadata");
287  assert(MD->getValue() == V && "Expected valid mapping");
288  Store.erase(I);
289
290  // Delete the metadata.
291  MD->replaceAllUsesWith(nullptr);
292  delete MD;
293}
294
295void ValueAsMetadata::handleRAUW(Value *From, Value *To) {
296  assert(From && "Expected valid value");
297  assert(To && "Expected valid value");
298  assert(From != To && "Expected changed value");
299  assert(From->getType() == To->getType() && "Unexpected type change");
300
301  LLVMContext &Context = From->getType()->getContext();
302  auto &Store = Context.pImpl->ValuesAsMetadata;
303  auto I = Store.find(From);
304  if (I == Store.end()) {
305    assert(!From->IsUsedByMD &&
306           "Expected From not to be used by metadata");
307    return;
308  }
309
310  // Remove old entry from the map.
311  assert(From->IsUsedByMD &&
312         "Expected From to be used by metadata");
313  From->IsUsedByMD = false;
314  ValueAsMetadata *MD = I->second;
315  assert(MD && "Expected valid metadata");
316  assert(MD->getValue() == From && "Expected valid mapping");
317  Store.erase(I);
318
319  if (isa<LocalAsMetadata>(MD)) {
320    if (auto *C = dyn_cast<Constant>(To)) {
321      // Local became a constant.
322      MD->replaceAllUsesWith(ConstantAsMetadata::get(C));
323      delete MD;
324      return;
325    }
326    if (getLocalFunction(From) && getLocalFunction(To) &&
327        getLocalFunction(From) != getLocalFunction(To)) {
328      // Function changed.
329      MD->replaceAllUsesWith(nullptr);
330      delete MD;
331      return;
332    }
333  } else if (!isa<Constant>(To)) {
334    // Changed to function-local value.
335    MD->replaceAllUsesWith(nullptr);
336    delete MD;
337    return;
338  }
339
340  auto *&Entry = Store[To];
341  if (Entry) {
342    // The target already exists.
343    MD->replaceAllUsesWith(Entry);
344    delete MD;
345    return;
346  }
347
348  // Update MD in place (and update the map entry).
349  assert(!To->IsUsedByMD &&
350         "Expected this to be the only metadata use");
351  To->IsUsedByMD = true;
352  MD->V = To;
353  Entry = MD;
354}
355
356//===----------------------------------------------------------------------===//
357// MDString implementation.
358//
359
360MDString *MDString::get(LLVMContext &Context, StringRef Str) {
361  auto &Store = Context.pImpl->MDStringCache;
362  auto I = Store.find(Str);
363  if (I != Store.end())
364    return &I->second;
365
366  auto *Entry =
367      StringMapEntry<MDString>::Create(Str, Store.getAllocator(), MDString());
368  bool WasInserted = Store.insert(Entry);
369  (void)WasInserted;
370  assert(WasInserted && "Expected entry to be inserted");
371  Entry->second.Entry = Entry;
372  return &Entry->second;
373}
374
375StringRef MDString::getString() const {
376  assert(Entry && "Expected to find string map entry");
377  return Entry->first();
378}
379
380//===----------------------------------------------------------------------===//
381// MDNode implementation.
382//
383
384// Assert that the MDNode types will not be unaligned by the objects
385// prepended to them.
386#define HANDLE_MDNODE_LEAF(CLASS)                                              \
387  static_assert(                                                               \
388      llvm::AlignOf<uint64_t>::Alignment >= llvm::AlignOf<CLASS>::Alignment,   \
389      "Alignment is insufficient after objects prepended to " #CLASS);
390#include "llvm/IR/Metadata.def"
391
392void *MDNode::operator new(size_t Size, unsigned NumOps) {
393  size_t OpSize = NumOps * sizeof(MDOperand);
394  // uint64_t is the most aligned type we need support (ensured by static_assert
395  // above)
396  OpSize = RoundUpToAlignment(OpSize, llvm::alignOf<uint64_t>());
397  void *Ptr = reinterpret_cast<char *>(::operator new(OpSize + Size)) + OpSize;
398  MDOperand *O = static_cast<MDOperand *>(Ptr);
399  for (MDOperand *E = O - NumOps; O != E; --O)
400    (void)new (O - 1) MDOperand;
401  return Ptr;
402}
403
404void MDNode::operator delete(void *Mem) {
405  MDNode *N = static_cast<MDNode *>(Mem);
406  size_t OpSize = N->NumOperands * sizeof(MDOperand);
407  OpSize = RoundUpToAlignment(OpSize, llvm::alignOf<uint64_t>());
408
409  MDOperand *O = static_cast<MDOperand *>(Mem);
410  for (MDOperand *E = O - N->NumOperands; O != E; --O)
411    (O - 1)->~MDOperand();
412  ::operator delete(reinterpret_cast<char *>(Mem) - OpSize);
413}
414
415MDNode::MDNode(LLVMContext &Context, unsigned ID, StorageType Storage,
416               ArrayRef<Metadata *> Ops1, ArrayRef<Metadata *> Ops2)
417    : Metadata(ID, Storage), NumOperands(Ops1.size() + Ops2.size()),
418      NumUnresolved(0), Context(Context) {
419  unsigned Op = 0;
420  for (Metadata *MD : Ops1)
421    setOperand(Op++, MD);
422  for (Metadata *MD : Ops2)
423    setOperand(Op++, MD);
424
425  if (isDistinct())
426    return;
427
428  if (isUniqued())
429    // Check whether any operands are unresolved, requiring re-uniquing.  If
430    // not, don't support RAUW.
431    if (!countUnresolvedOperands())
432      return;
433
434  this->Context.makeReplaceable(make_unique<ReplaceableMetadataImpl>(Context));
435}
436
437TempMDNode MDNode::clone() const {
438  switch (getMetadataID()) {
439  default:
440    llvm_unreachable("Invalid MDNode subclass");
441#define HANDLE_MDNODE_LEAF(CLASS)                                              \
442  case CLASS##Kind:                                                            \
443    return cast<CLASS>(this)->cloneImpl();
444#include "llvm/IR/Metadata.def"
445  }
446}
447
448static bool isOperandUnresolved(Metadata *Op) {
449  if (auto *N = dyn_cast_or_null<MDNode>(Op))
450    return !N->isResolved();
451  return false;
452}
453
454unsigned MDNode::countUnresolvedOperands() {
455  assert(NumUnresolved == 0 && "Expected unresolved ops to be uncounted");
456  NumUnresolved = std::count_if(op_begin(), op_end(), isOperandUnresolved);
457  return NumUnresolved;
458}
459
460void MDNode::makeUniqued() {
461  assert(isTemporary() && "Expected this to be temporary");
462  assert(!isResolved() && "Expected this to be unresolved");
463
464  // Enable uniquing callbacks.
465  for (auto &Op : mutable_operands())
466    Op.reset(Op.get(), this);
467
468  // Make this 'uniqued'.
469  Storage = Uniqued;
470  if (!countUnresolvedOperands())
471    resolve();
472
473  assert(isUniqued() && "Expected this to be uniqued");
474}
475
476void MDNode::makeDistinct() {
477  assert(isTemporary() && "Expected this to be temporary");
478  assert(!isResolved() && "Expected this to be unresolved");
479
480  // Pretend to be uniqued, resolve the node, and then store in distinct table.
481  Storage = Uniqued;
482  resolve();
483  storeDistinctInContext();
484
485  assert(isDistinct() && "Expected this to be distinct");
486  assert(isResolved() && "Expected this to be resolved");
487}
488
489void MDNode::resolve() {
490  assert(isUniqued() && "Expected this to be uniqued");
491  assert(!isResolved() && "Expected this to be unresolved");
492
493  // Move the map, so that this immediately looks resolved.
494  auto Uses = Context.takeReplaceableUses();
495  NumUnresolved = 0;
496  assert(isResolved() && "Expected this to be resolved");
497
498  // Drop RAUW support.
499  Uses->resolveAllUses();
500}
501
502void MDNode::resolveAfterOperandChange(Metadata *Old, Metadata *New) {
503  assert(NumUnresolved != 0 && "Expected unresolved operands");
504
505  // Check if an operand was resolved.
506  if (!isOperandUnresolved(Old)) {
507    if (isOperandUnresolved(New))
508      // An operand was un-resolved!
509      ++NumUnresolved;
510  } else if (!isOperandUnresolved(New))
511    decrementUnresolvedOperandCount();
512}
513
514void MDNode::decrementUnresolvedOperandCount() {
515  if (!--NumUnresolved)
516    // Last unresolved operand has just been resolved.
517    resolve();
518}
519
520void MDNode::resolveCycles(bool MDMaterialized) {
521  if (isResolved())
522    return;
523
524  // Resolve this node immediately.
525  resolve();
526
527  // Resolve all operands.
528  for (const auto &Op : operands()) {
529    auto *N = dyn_cast_or_null<MDNode>(Op);
530    if (!N)
531      continue;
532
533    if (N->isTemporary() && !MDMaterialized)
534      continue;
535    assert(!N->isTemporary() &&
536           "Expected all forward declarations to be resolved");
537    if (!N->isResolved())
538      N->resolveCycles();
539  }
540}
541
542static bool hasSelfReference(MDNode *N) {
543  for (Metadata *MD : N->operands())
544    if (MD == N)
545      return true;
546  return false;
547}
548
549MDNode *MDNode::replaceWithPermanentImpl() {
550  switch (getMetadataID()) {
551  default:
552    // If this type isn't uniquable, replace with a distinct node.
553    return replaceWithDistinctImpl();
554
555#define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
556  case CLASS##Kind:                                                            \
557    break;
558#include "llvm/IR/Metadata.def"
559  }
560
561  // Even if this type is uniquable, self-references have to be distinct.
562  if (hasSelfReference(this))
563    return replaceWithDistinctImpl();
564  return replaceWithUniquedImpl();
565}
566
567MDNode *MDNode::replaceWithUniquedImpl() {
568  // Try to uniquify in place.
569  MDNode *UniquedNode = uniquify();
570
571  if (UniquedNode == this) {
572    makeUniqued();
573    return this;
574  }
575
576  // Collision, so RAUW instead.
577  replaceAllUsesWith(UniquedNode);
578  deleteAsSubclass();
579  return UniquedNode;
580}
581
582MDNode *MDNode::replaceWithDistinctImpl() {
583  makeDistinct();
584  return this;
585}
586
587void MDTuple::recalculateHash() {
588  setHash(MDTupleInfo::KeyTy::calculateHash(this));
589}
590
591void MDNode::dropAllReferences() {
592  for (unsigned I = 0, E = NumOperands; I != E; ++I)
593    setOperand(I, nullptr);
594  if (!isResolved()) {
595    Context.getReplaceableUses()->resolveAllUses(/* ResolveUsers */ false);
596    (void)Context.takeReplaceableUses();
597  }
598}
599
600void MDNode::handleChangedOperand(void *Ref, Metadata *New) {
601  unsigned Op = static_cast<MDOperand *>(Ref) - op_begin();
602  assert(Op < getNumOperands() && "Expected valid operand");
603
604  if (!isUniqued()) {
605    // This node is not uniqued.  Just set the operand and be done with it.
606    setOperand(Op, New);
607    return;
608  }
609
610  // This node is uniqued.
611  eraseFromStore();
612
613  Metadata *Old = getOperand(Op);
614  setOperand(Op, New);
615
616  // Drop uniquing for self-reference cycles.
617  if (New == this) {
618    if (!isResolved())
619      resolve();
620    storeDistinctInContext();
621    return;
622  }
623
624  // Re-unique the node.
625  auto *Uniqued = uniquify();
626  if (Uniqued == this) {
627    if (!isResolved())
628      resolveAfterOperandChange(Old, New);
629    return;
630  }
631
632  // Collision.
633  if (!isResolved()) {
634    // Still unresolved, so RAUW.
635    //
636    // First, clear out all operands to prevent any recursion (similar to
637    // dropAllReferences(), but we still need the use-list).
638    for (unsigned O = 0, E = getNumOperands(); O != E; ++O)
639      setOperand(O, nullptr);
640    Context.getReplaceableUses()->replaceAllUsesWith(Uniqued);
641    deleteAsSubclass();
642    return;
643  }
644
645  // Store in non-uniqued form if RAUW isn't possible.
646  storeDistinctInContext();
647}
648
649void MDNode::deleteAsSubclass() {
650  switch (getMetadataID()) {
651  default:
652    llvm_unreachable("Invalid subclass of MDNode");
653#define HANDLE_MDNODE_LEAF(CLASS)                                              \
654  case CLASS##Kind:                                                            \
655    delete cast<CLASS>(this);                                                  \
656    break;
657#include "llvm/IR/Metadata.def"
658  }
659}
660
661template <class T, class InfoT>
662static T *uniquifyImpl(T *N, DenseSet<T *, InfoT> &Store) {
663  if (T *U = getUniqued(Store, N))
664    return U;
665
666  Store.insert(N);
667  return N;
668}
669
670template <class NodeTy> struct MDNode::HasCachedHash {
671  typedef char Yes[1];
672  typedef char No[2];
673  template <class U, U Val> struct SFINAE {};
674
675  template <class U>
676  static Yes &check(SFINAE<void (U::*)(unsigned), &U::setHash> *);
677  template <class U> static No &check(...);
678
679  static const bool value = sizeof(check<NodeTy>(nullptr)) == sizeof(Yes);
680};
681
682MDNode *MDNode::uniquify() {
683  assert(!hasSelfReference(this) && "Cannot uniquify a self-referencing node");
684
685  // Try to insert into uniquing store.
686  switch (getMetadataID()) {
687  default:
688    llvm_unreachable("Invalid or non-uniquable subclass of MDNode");
689#define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
690  case CLASS##Kind: {                                                          \
691    CLASS *SubclassThis = cast<CLASS>(this);                                   \
692    std::integral_constant<bool, HasCachedHash<CLASS>::value>                  \
693        ShouldRecalculateHash;                                                 \
694    dispatchRecalculateHash(SubclassThis, ShouldRecalculateHash);              \
695    return uniquifyImpl(SubclassThis, getContext().pImpl->CLASS##s);           \
696  }
697#include "llvm/IR/Metadata.def"
698  }
699}
700
701void MDNode::eraseFromStore() {
702  switch (getMetadataID()) {
703  default:
704    llvm_unreachable("Invalid or non-uniquable subclass of MDNode");
705#define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
706  case CLASS##Kind:                                                            \
707    getContext().pImpl->CLASS##s.erase(cast<CLASS>(this));                     \
708    break;
709#include "llvm/IR/Metadata.def"
710  }
711}
712
713MDTuple *MDTuple::getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
714                          StorageType Storage, bool ShouldCreate) {
715  unsigned Hash = 0;
716  if (Storage == Uniqued) {
717    MDTupleInfo::KeyTy Key(MDs);
718    if (auto *N = getUniqued(Context.pImpl->MDTuples, Key))
719      return N;
720    if (!ShouldCreate)
721      return nullptr;
722    Hash = Key.getHash();
723  } else {
724    assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
725  }
726
727  return storeImpl(new (MDs.size()) MDTuple(Context, Storage, Hash, MDs),
728                   Storage, Context.pImpl->MDTuples);
729}
730
731void MDNode::deleteTemporary(MDNode *N) {
732  assert(N->isTemporary() && "Expected temporary node");
733  N->replaceAllUsesWith(nullptr);
734  N->deleteAsSubclass();
735}
736
737void MDNode::storeDistinctInContext() {
738  assert(isResolved() && "Expected resolved nodes");
739  Storage = Distinct;
740
741  // Reset the hash.
742  switch (getMetadataID()) {
743  default:
744    llvm_unreachable("Invalid subclass of MDNode");
745#define HANDLE_MDNODE_LEAF(CLASS)                                              \
746  case CLASS##Kind: {                                                          \
747    std::integral_constant<bool, HasCachedHash<CLASS>::value> ShouldResetHash; \
748    dispatchResetHash(cast<CLASS>(this), ShouldResetHash);                     \
749    break;                                                                     \
750  }
751#include "llvm/IR/Metadata.def"
752  }
753
754  getContext().pImpl->DistinctMDNodes.insert(this);
755}
756
757void MDNode::replaceOperandWith(unsigned I, Metadata *New) {
758  if (getOperand(I) == New)
759    return;
760
761  if (!isUniqued()) {
762    setOperand(I, New);
763    return;
764  }
765
766  handleChangedOperand(mutable_begin() + I, New);
767}
768
769void MDNode::setOperand(unsigned I, Metadata *New) {
770  assert(I < NumOperands);
771  mutable_begin()[I].reset(New, isUniqued() ? this : nullptr);
772}
773
774/// \brief Get a node, or a self-reference that looks like it.
775///
776/// Special handling for finding self-references, for use by \a
777/// MDNode::concatenate() and \a MDNode::intersect() to maintain behaviour from
778/// when self-referencing nodes were still uniqued.  If the first operand has
779/// the same operands as \c Ops, return the first operand instead.
780static MDNode *getOrSelfReference(LLVMContext &Context,
781                                  ArrayRef<Metadata *> Ops) {
782  if (!Ops.empty())
783    if (MDNode *N = dyn_cast_or_null<MDNode>(Ops[0]))
784      if (N->getNumOperands() == Ops.size() && N == N->getOperand(0)) {
785        for (unsigned I = 1, E = Ops.size(); I != E; ++I)
786          if (Ops[I] != N->getOperand(I))
787            return MDNode::get(Context, Ops);
788        return N;
789      }
790
791  return MDNode::get(Context, Ops);
792}
793
794MDNode *MDNode::concatenate(MDNode *A, MDNode *B) {
795  if (!A)
796    return B;
797  if (!B)
798    return A;
799
800  SmallVector<Metadata *, 4> MDs;
801  MDs.reserve(A->getNumOperands() + B->getNumOperands());
802  MDs.append(A->op_begin(), A->op_end());
803  MDs.append(B->op_begin(), B->op_end());
804
805  // FIXME: This preserves long-standing behaviour, but is it really the right
806  // behaviour?  Or was that an unintended side-effect of node uniquing?
807  return getOrSelfReference(A->getContext(), MDs);
808}
809
810MDNode *MDNode::intersect(MDNode *A, MDNode *B) {
811  if (!A || !B)
812    return nullptr;
813
814  SmallVector<Metadata *, 4> MDs;
815  for (Metadata *MD : A->operands())
816    if (std::find(B->op_begin(), B->op_end(), MD) != B->op_end())
817      MDs.push_back(MD);
818
819  // FIXME: This preserves long-standing behaviour, but is it really the right
820  // behaviour?  Or was that an unintended side-effect of node uniquing?
821  return getOrSelfReference(A->getContext(), MDs);
822}
823
824MDNode *MDNode::getMostGenericAliasScope(MDNode *A, MDNode *B) {
825  if (!A || !B)
826    return nullptr;
827
828  SmallVector<Metadata *, 4> MDs(B->op_begin(), B->op_end());
829  for (Metadata *MD : A->operands())
830    if (std::find(B->op_begin(), B->op_end(), MD) == B->op_end())
831      MDs.push_back(MD);
832
833  // FIXME: This preserves long-standing behaviour, but is it really the right
834  // behaviour?  Or was that an unintended side-effect of node uniquing?
835  return getOrSelfReference(A->getContext(), MDs);
836}
837
838MDNode *MDNode::getMostGenericFPMath(MDNode *A, MDNode *B) {
839  if (!A || !B)
840    return nullptr;
841
842  APFloat AVal = mdconst::extract<ConstantFP>(A->getOperand(0))->getValueAPF();
843  APFloat BVal = mdconst::extract<ConstantFP>(B->getOperand(0))->getValueAPF();
844  if (AVal.compare(BVal) == APFloat::cmpLessThan)
845    return A;
846  return B;
847}
848
849static bool isContiguous(const ConstantRange &A, const ConstantRange &B) {
850  return A.getUpper() == B.getLower() || A.getLower() == B.getUpper();
851}
852
853static bool canBeMerged(const ConstantRange &A, const ConstantRange &B) {
854  return !A.intersectWith(B).isEmptySet() || isContiguous(A, B);
855}
856
857static bool tryMergeRange(SmallVectorImpl<ConstantInt *> &EndPoints,
858                          ConstantInt *Low, ConstantInt *High) {
859  ConstantRange NewRange(Low->getValue(), High->getValue());
860  unsigned Size = EndPoints.size();
861  APInt LB = EndPoints[Size - 2]->getValue();
862  APInt LE = EndPoints[Size - 1]->getValue();
863  ConstantRange LastRange(LB, LE);
864  if (canBeMerged(NewRange, LastRange)) {
865    ConstantRange Union = LastRange.unionWith(NewRange);
866    Type *Ty = High->getType();
867    EndPoints[Size - 2] =
868        cast<ConstantInt>(ConstantInt::get(Ty, Union.getLower()));
869    EndPoints[Size - 1] =
870        cast<ConstantInt>(ConstantInt::get(Ty, Union.getUpper()));
871    return true;
872  }
873  return false;
874}
875
876static void addRange(SmallVectorImpl<ConstantInt *> &EndPoints,
877                     ConstantInt *Low, ConstantInt *High) {
878  if (!EndPoints.empty())
879    if (tryMergeRange(EndPoints, Low, High))
880      return;
881
882  EndPoints.push_back(Low);
883  EndPoints.push_back(High);
884}
885
886MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
887  // Given two ranges, we want to compute the union of the ranges. This
888  // is slightly complitade by having to combine the intervals and merge
889  // the ones that overlap.
890
891  if (!A || !B)
892    return nullptr;
893
894  if (A == B)
895    return A;
896
897  // First, walk both lists in older of the lower boundary of each interval.
898  // At each step, try to merge the new interval to the last one we adedd.
899  SmallVector<ConstantInt *, 4> EndPoints;
900  int AI = 0;
901  int BI = 0;
902  int AN = A->getNumOperands() / 2;
903  int BN = B->getNumOperands() / 2;
904  while (AI < AN && BI < BN) {
905    ConstantInt *ALow = mdconst::extract<ConstantInt>(A->getOperand(2 * AI));
906    ConstantInt *BLow = mdconst::extract<ConstantInt>(B->getOperand(2 * BI));
907
908    if (ALow->getValue().slt(BLow->getValue())) {
909      addRange(EndPoints, ALow,
910               mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
911      ++AI;
912    } else {
913      addRange(EndPoints, BLow,
914               mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
915      ++BI;
916    }
917  }
918  while (AI < AN) {
919    addRange(EndPoints, mdconst::extract<ConstantInt>(A->getOperand(2 * AI)),
920             mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
921    ++AI;
922  }
923  while (BI < BN) {
924    addRange(EndPoints, mdconst::extract<ConstantInt>(B->getOperand(2 * BI)),
925             mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
926    ++BI;
927  }
928
929  // If we have more than 2 ranges (4 endpoints) we have to try to merge
930  // the last and first ones.
931  unsigned Size = EndPoints.size();
932  if (Size > 4) {
933    ConstantInt *FB = EndPoints[0];
934    ConstantInt *FE = EndPoints[1];
935    if (tryMergeRange(EndPoints, FB, FE)) {
936      for (unsigned i = 0; i < Size - 2; ++i) {
937        EndPoints[i] = EndPoints[i + 2];
938      }
939      EndPoints.resize(Size - 2);
940    }
941  }
942
943  // If in the end we have a single range, it is possible that it is now the
944  // full range. Just drop the metadata in that case.
945  if (EndPoints.size() == 2) {
946    ConstantRange Range(EndPoints[0]->getValue(), EndPoints[1]->getValue());
947    if (Range.isFullSet())
948      return nullptr;
949  }
950
951  SmallVector<Metadata *, 4> MDs;
952  MDs.reserve(EndPoints.size());
953  for (auto *I : EndPoints)
954    MDs.push_back(ConstantAsMetadata::get(I));
955  return MDNode::get(A->getContext(), MDs);
956}
957
958MDNode *MDNode::getMostGenericAlignmentOrDereferenceable(MDNode *A, MDNode *B) {
959  if (!A || !B)
960    return nullptr;
961
962  ConstantInt *AVal = mdconst::extract<ConstantInt>(A->getOperand(0));
963  ConstantInt *BVal = mdconst::extract<ConstantInt>(B->getOperand(0));
964  if (AVal->getZExtValue() < BVal->getZExtValue())
965    return A;
966  return B;
967}
968
969//===----------------------------------------------------------------------===//
970// NamedMDNode implementation.
971//
972
973static SmallVector<TrackingMDRef, 4> &getNMDOps(void *Operands) {
974  return *(SmallVector<TrackingMDRef, 4> *)Operands;
975}
976
977NamedMDNode::NamedMDNode(const Twine &N)
978    : Name(N.str()), Parent(nullptr),
979      Operands(new SmallVector<TrackingMDRef, 4>()) {}
980
981NamedMDNode::~NamedMDNode() {
982  dropAllReferences();
983  delete &getNMDOps(Operands);
984}
985
986unsigned NamedMDNode::getNumOperands() const {
987  return (unsigned)getNMDOps(Operands).size();
988}
989
990MDNode *NamedMDNode::getOperand(unsigned i) const {
991  assert(i < getNumOperands() && "Invalid Operand number!");
992  auto *N = getNMDOps(Operands)[i].get();
993  return cast_or_null<MDNode>(N);
994}
995
996void NamedMDNode::addOperand(MDNode *M) { getNMDOps(Operands).emplace_back(M); }
997
998void NamedMDNode::setOperand(unsigned I, MDNode *New) {
999  assert(I < getNumOperands() && "Invalid operand number");
1000  getNMDOps(Operands)[I].reset(New);
1001}
1002
1003void NamedMDNode::eraseFromParent() {
1004  getParent()->eraseNamedMetadata(this);
1005}
1006
1007void NamedMDNode::dropAllReferences() {
1008  getNMDOps(Operands).clear();
1009}
1010
1011StringRef NamedMDNode::getName() const {
1012  return StringRef(Name);
1013}
1014
1015//===----------------------------------------------------------------------===//
1016// Instruction Metadata method implementations.
1017//
1018void MDAttachmentMap::set(unsigned ID, MDNode &MD) {
1019  for (auto &I : Attachments)
1020    if (I.first == ID) {
1021      I.second.reset(&MD);
1022      return;
1023    }
1024  Attachments.emplace_back(std::piecewise_construct, std::make_tuple(ID),
1025                           std::make_tuple(&MD));
1026}
1027
1028void MDAttachmentMap::erase(unsigned ID) {
1029  if (empty())
1030    return;
1031
1032  // Common case is one/last value.
1033  if (Attachments.back().first == ID) {
1034    Attachments.pop_back();
1035    return;
1036  }
1037
1038  for (auto I = Attachments.begin(), E = std::prev(Attachments.end()); I != E;
1039       ++I)
1040    if (I->first == ID) {
1041      *I = std::move(Attachments.back());
1042      Attachments.pop_back();
1043      return;
1044    }
1045}
1046
1047MDNode *MDAttachmentMap::lookup(unsigned ID) const {
1048  for (const auto &I : Attachments)
1049    if (I.first == ID)
1050      return I.second;
1051  return nullptr;
1052}
1053
1054void MDAttachmentMap::getAll(
1055    SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1056  Result.append(Attachments.begin(), Attachments.end());
1057
1058  // Sort the resulting array so it is stable.
1059  if (Result.size() > 1)
1060    array_pod_sort(Result.begin(), Result.end());
1061}
1062
1063void Instruction::setMetadata(StringRef Kind, MDNode *Node) {
1064  if (!Node && !hasMetadata())
1065    return;
1066  setMetadata(getContext().getMDKindID(Kind), Node);
1067}
1068
1069MDNode *Instruction::getMetadataImpl(StringRef Kind) const {
1070  return getMetadataImpl(getContext().getMDKindID(Kind));
1071}
1072
1073void Instruction::dropUnknownNonDebugMetadata(ArrayRef<unsigned> KnownIDs) {
1074  SmallSet<unsigned, 5> KnownSet;
1075  KnownSet.insert(KnownIDs.begin(), KnownIDs.end());
1076
1077  if (!hasMetadataHashEntry())
1078    return; // Nothing to remove!
1079
1080  auto &InstructionMetadata = getContext().pImpl->InstructionMetadata;
1081
1082  if (KnownSet.empty()) {
1083    // Just drop our entry at the store.
1084    InstructionMetadata.erase(this);
1085    setHasMetadataHashEntry(false);
1086    return;
1087  }
1088
1089  auto &Info = InstructionMetadata[this];
1090  Info.remove_if([&KnownSet](const std::pair<unsigned, TrackingMDNodeRef> &I) {
1091    return !KnownSet.count(I.first);
1092  });
1093
1094  if (Info.empty()) {
1095    // Drop our entry at the store.
1096    InstructionMetadata.erase(this);
1097    setHasMetadataHashEntry(false);
1098  }
1099}
1100
1101/// setMetadata - Set the metadata of the specified kind to the specified
1102/// node.  This updates/replaces metadata if already present, or removes it if
1103/// Node is null.
1104void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
1105  if (!Node && !hasMetadata())
1106    return;
1107
1108  // Handle 'dbg' as a special case since it is not stored in the hash table.
1109  if (KindID == LLVMContext::MD_dbg) {
1110    DbgLoc = DebugLoc(Node);
1111    return;
1112  }
1113
1114  // Handle the case when we're adding/updating metadata on an instruction.
1115  if (Node) {
1116    auto &Info = getContext().pImpl->InstructionMetadata[this];
1117    assert(!Info.empty() == hasMetadataHashEntry() &&
1118           "HasMetadata bit is wonked");
1119    if (Info.empty())
1120      setHasMetadataHashEntry(true);
1121    Info.set(KindID, *Node);
1122    return;
1123  }
1124
1125  // Otherwise, we're removing metadata from an instruction.
1126  assert((hasMetadataHashEntry() ==
1127          (getContext().pImpl->InstructionMetadata.count(this) > 0)) &&
1128         "HasMetadata bit out of date!");
1129  if (!hasMetadataHashEntry())
1130    return;  // Nothing to remove!
1131  auto &Info = getContext().pImpl->InstructionMetadata[this];
1132
1133  // Handle removal of an existing value.
1134  Info.erase(KindID);
1135
1136  if (!Info.empty())
1137    return;
1138
1139  getContext().pImpl->InstructionMetadata.erase(this);
1140  setHasMetadataHashEntry(false);
1141}
1142
1143void Instruction::setAAMetadata(const AAMDNodes &N) {
1144  setMetadata(LLVMContext::MD_tbaa, N.TBAA);
1145  setMetadata(LLVMContext::MD_alias_scope, N.Scope);
1146  setMetadata(LLVMContext::MD_noalias, N.NoAlias);
1147}
1148
1149MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
1150  // Handle 'dbg' as a special case since it is not stored in the hash table.
1151  if (KindID == LLVMContext::MD_dbg)
1152    return DbgLoc.getAsMDNode();
1153
1154  if (!hasMetadataHashEntry())
1155    return nullptr;
1156  auto &Info = getContext().pImpl->InstructionMetadata[this];
1157  assert(!Info.empty() && "bit out of sync with hash table");
1158
1159  return Info.lookup(KindID);
1160}
1161
1162void Instruction::getAllMetadataImpl(
1163    SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1164  Result.clear();
1165
1166  // Handle 'dbg' as a special case since it is not stored in the hash table.
1167  if (DbgLoc) {
1168    Result.push_back(
1169        std::make_pair((unsigned)LLVMContext::MD_dbg, DbgLoc.getAsMDNode()));
1170    if (!hasMetadataHashEntry()) return;
1171  }
1172
1173  assert(hasMetadataHashEntry() &&
1174         getContext().pImpl->InstructionMetadata.count(this) &&
1175         "Shouldn't have called this");
1176  const auto &Info = getContext().pImpl->InstructionMetadata.find(this)->second;
1177  assert(!Info.empty() && "Shouldn't have called this");
1178  Info.getAll(Result);
1179}
1180
1181void Instruction::getAllMetadataOtherThanDebugLocImpl(
1182    SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1183  Result.clear();
1184  assert(hasMetadataHashEntry() &&
1185         getContext().pImpl->InstructionMetadata.count(this) &&
1186         "Shouldn't have called this");
1187  const auto &Info = getContext().pImpl->InstructionMetadata.find(this)->second;
1188  assert(!Info.empty() && "Shouldn't have called this");
1189  Info.getAll(Result);
1190}
1191
1192/// clearMetadataHashEntries - Clear all hashtable-based metadata from
1193/// this instruction.
1194void Instruction::clearMetadataHashEntries() {
1195  assert(hasMetadataHashEntry() && "Caller should check");
1196  getContext().pImpl->InstructionMetadata.erase(this);
1197  setHasMetadataHashEntry(false);
1198}
1199
1200MDNode *Function::getMetadata(unsigned KindID) const {
1201  if (!hasMetadata())
1202    return nullptr;
1203  return getContext().pImpl->FunctionMetadata[this].lookup(KindID);
1204}
1205
1206MDNode *Function::getMetadata(StringRef Kind) const {
1207  if (!hasMetadata())
1208    return nullptr;
1209  return getMetadata(getContext().getMDKindID(Kind));
1210}
1211
1212void Function::setMetadata(unsigned KindID, MDNode *MD) {
1213  if (MD) {
1214    if (!hasMetadata())
1215      setHasMetadataHashEntry(true);
1216
1217    getContext().pImpl->FunctionMetadata[this].set(KindID, *MD);
1218    return;
1219  }
1220
1221  // Nothing to unset.
1222  if (!hasMetadata())
1223    return;
1224
1225  auto &Store = getContext().pImpl->FunctionMetadata[this];
1226  Store.erase(KindID);
1227  if (Store.empty())
1228    clearMetadata();
1229}
1230
1231void Function::setMetadata(StringRef Kind, MDNode *MD) {
1232  if (!MD && !hasMetadata())
1233    return;
1234  setMetadata(getContext().getMDKindID(Kind), MD);
1235}
1236
1237void Function::getAllMetadata(
1238    SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const {
1239  MDs.clear();
1240
1241  if (!hasMetadata())
1242    return;
1243
1244  getContext().pImpl->FunctionMetadata[this].getAll(MDs);
1245}
1246
1247void Function::dropUnknownMetadata(ArrayRef<unsigned> KnownIDs) {
1248  if (!hasMetadata())
1249    return;
1250  if (KnownIDs.empty()) {
1251    clearMetadata();
1252    return;
1253  }
1254
1255  SmallSet<unsigned, 5> KnownSet;
1256  KnownSet.insert(KnownIDs.begin(), KnownIDs.end());
1257
1258  auto &Store = getContext().pImpl->FunctionMetadata[this];
1259  assert(!Store.empty());
1260
1261  Store.remove_if([&KnownSet](const std::pair<unsigned, TrackingMDNodeRef> &I) {
1262    return !KnownSet.count(I.first);
1263  });
1264
1265  if (Store.empty())
1266    clearMetadata();
1267}
1268
1269void Function::clearMetadata() {
1270  if (!hasMetadata())
1271    return;
1272  getContext().pImpl->FunctionMetadata.erase(this);
1273  setHasMetadataHashEntry(false);
1274}
1275
1276void Function::setSubprogram(DISubprogram *SP) {
1277  setMetadata(LLVMContext::MD_dbg, SP);
1278}
1279
1280DISubprogram *Function::getSubprogram() const {
1281  return cast_or_null<DISubprogram>(getMetadata(LLVMContext::MD_dbg));
1282}
1283