lib/IR/Metadata.cpp

   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 "LLVMContextImpl.h"
  15 #include "MetadataImpl.h"
  16 #include "SymbolTableListTraitsImpl.h"
  17 #include "llvm/ADT/APFloat.h"
  18 #include "llvm/ADT/APInt.h"
  19 #include "llvm/ADT/ArrayRef.h"
  20 #include "llvm/ADT/DenseSet.h"
  21 #include "llvm/ADT/None.h"
  22 #include "llvm/ADT/STLExtras.h"
  23 #include "llvm/ADT/SetVector.h"
  24 #include "llvm/ADT/SmallPtrSet.h"
  25 #include "llvm/ADT/SmallSet.h"
  26 #include "llvm/ADT/SmallVector.h"
  27 #include "llvm/ADT/StringMap.h"
  28 #include "llvm/ADT/StringRef.h"
  29 #include "llvm/ADT/Twine.h"
  30 #include "llvm/IR/Argument.h"
  31 #include "llvm/IR/BasicBlock.h"
  32 #include "llvm/IR/Constant.h"
  33 #include "llvm/IR/ConstantRange.h"
  34 #include "llvm/IR/Constants.h"
  35 #include "llvm/IR/DebugInfoMetadata.h"
  36 #include "llvm/IR/DebugLoc.h"
  37 #include "llvm/IR/Function.h"
  38 #include "llvm/IR/GlobalObject.h"
  39 #include "llvm/IR/GlobalVariable.h"
  40 #include "llvm/IR/Instruction.h"
  41 #include "llvm/IR/LLVMContext.h"
  42 #include "llvm/IR/Metadata.h"
  43 #include "llvm/IR/Module.h"
  44 #include "llvm/IR/TrackingMDRef.h"
  45 #include "llvm/IR/Type.h"
  46 #include "llvm/IR/Value.h"
  47 #include "llvm/IR/ValueHandle.h"
  48 #include "llvm/Support/Casting.h"
  49 #include "llvm/Support/ErrorHandling.h"
  50 #include "llvm/Support/MathExtras.h"
  51 #include <algorithm>
  52 #include <cassert>
  53 #include <cstddef>
  54 #include <cstdint>
  55 #include <iterator>
  56 #include <tuple>
  57 #include <type_traits>
  58 #include <utility>
  59 #include <vector>
  60
  61 using namespace llvm;
  62
  63 MetadataAsValue::MetadataAsValue(Type *Ty, Metadata *MD)
  64     : Value(Ty, MetadataAsValueVal), MD(MD) {
  65   track();
  66 }
  67
  68 MetadataAsValue::~MetadataAsValue() {
  69   getType()->getContext().pImpl->MetadataAsValues.erase(MD);
  70   untrack();
  71 }
  72
  73 /// Canonicalize metadata arguments to intrinsics.
  74 ///
  75 /// To support bitcode upgrades (and assembly semantic sugar) for \a
  76 /// MetadataAsValue, we need to canonicalize certain metadata.
  77 ///
  78 ///   - nullptr is replaced by an empty MDNode.
  79 ///   - An MDNode with a single null operand is replaced by an empty MDNode.
  80 ///   - An MDNode whose only operand is a \a ConstantAsMetadata gets skipped.
  81 ///
  82 /// This maintains readability of bitcode from when metadata was a type of
  83 /// value, and these bridges were unnecessary.
  84 static Metadata *canonicalizeMetadataForValue(LLVMContext &Context,
  85                                               Metadata *MD) {
  86   if (!MD)
  87     // !{}
  88     return MDNode::get(Context, None);
  89
  90   // Return early if this isn't a single-operand MDNode.
  91   auto *N = dyn_cast<MDNode>(MD);
  92   if (!N || N->getNumOperands() != 1)
  93     return MD;
  94
  95   if (!N->getOperand(0))
  96     // !{}
  97     return MDNode::get(Context, None);
  98
  99   if (auto *C = dyn_cast<ConstantAsMetadata>(N->getOperand(0)))
 100     // Look through the MDNode.
 101     return C;
 102
 103   return MD;
 104 }
 105
 106 MetadataAsValue *MetadataAsValue::get(LLVMContext &Context, Metadata *MD) {
 107   MD = canonicalizeMetadataForValue(Context, MD);
 108   auto *&Entry = Context.pImpl->MetadataAsValues[MD];
 109   if (!Entry)
 110     Entry = new MetadataAsValue(Type::getMetadataTy(Context), MD);
 111   return Entry;
 112 }
 113
 114 MetadataAsValue *MetadataAsValue::getIfExists(LLVMContext &Context,
 115                                               Metadata *MD) {
 116   MD = canonicalizeMetadataForValue(Context, MD);
 117   auto &Store = Context.pImpl->MetadataAsValues;
 118   return Store.lookup(MD);
 119 }
 120
 121 void MetadataAsValue::handleChangedMetadata(Metadata *MD) {
 122   LLVMContext &Context = getContext();
 123   MD = canonicalizeMetadataForValue(Context, MD);
 124   auto &Store = Context.pImpl->MetadataAsValues;
 125
 126   // Stop tracking the old metadata.
 127   Store.erase(this->MD);
 128   untrack();
 129   this->MD = nullptr;
 130
 131   // Start tracking MD, or RAUW if necessary.
 132   auto *&Entry = Store[MD];
 133   if (Entry) {
 134     replaceAllUsesWith(Entry);
 135     delete this;
 136     return;
 137   }
 138
 139   this->MD = MD;
 140   track();
 141   Entry = this;
 142 }
 143
 144 void MetadataAsValue::track() {
 145   if (MD)
 146     MetadataTracking::track(&MD, *MD, *this);
 147 }
 148
 149 void MetadataAsValue::untrack() {
 150   if (MD)
 151     MetadataTracking::untrack(MD);
 152 }
 153
 154 bool MetadataTracking::track(void *Ref, Metadata &MD, OwnerTy Owner) {
 155   assert(Ref && "Expected live reference");
 156   assert((Owner || *static_cast<Metadata **>(Ref) == &MD) &&
 157          "Reference without owner must be direct");
 158   if (auto *R = ReplaceableMetadataImpl::getOrCreate(MD)) {
 159     R->addRef(Ref, Owner);
 160     return true;
 161   }
 162   if (auto *PH = dyn_cast<DistinctMDOperandPlaceholder>(&MD)) {
 163     assert(!PH->Use && "Placeholders can only be used once");
 164     assert(!Owner && "Unexpected callback to owner");
 165     PH->Use = static_cast<Metadata **>(Ref);
 166     return true;
 167   }
 168   return false;
 169 }
 170
 171 void MetadataTracking::untrack(void *Ref, Metadata &MD) {
 172   assert(Ref && "Expected live reference");
 173   if (auto *R = ReplaceableMetadataImpl::getIfExists(MD))
 174     R->dropRef(Ref);
 175   else if (auto *PH = dyn_cast<DistinctMDOperandPlaceholder>(&MD))
 176     PH->Use = nullptr;
 177 }
 178
 179 bool MetadataTracking::retrack(void *Ref, Metadata &MD, void *New) {
 180   assert(Ref && "Expected live reference");
 181   assert(New && "Expected live reference");
 182   assert(Ref != New && "Expected change");
 183   if (auto *R = ReplaceableMetadataImpl::getIfExists(MD)) {
 184     R->moveRef(Ref, New, MD);
 185     return true;
 186   }
 187   assert(!isa<DistinctMDOperandPlaceholder>(MD) &&
 188          "Unexpected move of an MDOperand");
 189   assert(!isReplaceable(MD) &&
 190          "Expected un-replaceable metadata, since we didn't move a reference");
 191   return false;
 192 }
 193
 194 bool MetadataTracking::isReplaceable(const Metadata &MD) {
 195   return ReplaceableMetadataImpl::isReplaceable(MD);
 196 }
 197
 198 void ReplaceableMetadataImpl::addRef(void *Ref, OwnerTy Owner) {
 199   bool WasInserted =
 200       UseMap.insert(std::make_pair(Ref, std::make_pair(Owner, NextIndex)))
 201           .second;
 202   (void)WasInserted;
 203   assert(WasInserted && "Expected to add a reference");
 204
 205   ++NextIndex;
 206   assert(NextIndex != 0 && "Unexpected overflow");
 207 }
 208
 209 void ReplaceableMetadataImpl::dropRef(void *Ref) {
 210   bool WasErased = UseMap.erase(Ref);
 211   (void)WasErased;
 212   assert(WasErased && "Expected to drop a reference");
 213 }
 214
 215 void ReplaceableMetadataImpl::moveRef(void *Ref, void *New,
 216                                       const Metadata &MD) {
 217   auto I = UseMap.find(Ref);
 218   assert(I != UseMap.end() && "Expected to move a reference");
 219   auto OwnerAndIndex = I->second;
 220   UseMap.erase(I);
 221   bool WasInserted = UseMap.insert(std::make_pair(New, OwnerAndIndex)).second;
 222   (void)WasInserted;
 223   assert(WasInserted && "Expected to add a reference");
 224
 225   // Check that the references are direct if there's no owner.
 226   (void)MD;
 227   assert((OwnerAndIndex.first || *static_cast<Metadata **>(Ref) == &MD) &&
 228          "Reference without owner must be direct");
 229   assert((OwnerAndIndex.first || *static_cast<Metadata **>(New) == &MD) &&
 230          "Reference without owner must be direct");
 231 }
 232
 233 void ReplaceableMetadataImpl::replaceAllUsesWith(Metadata *MD) {
 234   if (UseMap.empty())
 235     return;
 236
 237   // Copy out uses since UseMap will get touched below.
 238   using UseTy = std::pair<void *, std::pair<OwnerTy, uint64_t>>;
 239   SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
 240   llvm::sort(Uses, [](const UseTy &L, const UseTy &R) {
 241     return L.second.second < R.second.second;
 242   });
 243   for (const auto &Pair : Uses) {
 244     // Check that this Ref hasn't disappeared after RAUW (when updating a
 245     // previous Ref).
 246     if (!UseMap.count(Pair.first))
 247       continue;
 248
 249     OwnerTy Owner = Pair.second.first;
 250     if (!Owner) {
 251       // Update unowned tracking references directly.
 252       Metadata *&Ref = *static_cast<Metadata **>(Pair.first);
 253       Ref = MD;
 254       if (MD)
 255         MetadataTracking::track(Ref);
 256       UseMap.erase(Pair.first);
 257       continue;
 258     }
 259
 260     // Check for MetadataAsValue.
 261     if (Owner.is<MetadataAsValue *>()) {
 262       Owner.get<MetadataAsValue *>()->handleChangedMetadata(MD);
 263       continue;
 264     }
 265
 266     // There's a Metadata owner -- dispatch.
 267     Metadata *OwnerMD = Owner.get<Metadata *>();
 268     switch (OwnerMD->getMetadataID()) {
 269 #define HANDLE_METADATA_LEAF(CLASS)                                            \
 270   case Metadata::CLASS##Kind:                                                  \
 271     cast<CLASS>(OwnerMD)->handleChangedOperand(Pair.first, MD);                \
 272     continue;
 273 #include "llvm/IR/Metadata.def"
 274     default:
 275       llvm_unreachable("Invalid metadata subclass");
 276     }
 277   }
 278   assert(UseMap.empty() && "Expected all uses to be replaced");
 279 }
 280
 281 void ReplaceableMetadataImpl::resolveAllUses(bool ResolveUsers) {
 282   if (UseMap.empty())
 283     return;
 284
 285   if (!ResolveUsers) {
 286     UseMap.clear();
 287     return;
 288   }
 289
 290   // Copy out uses since UseMap could get touched below.
 291   using UseTy = std::pair<void *, std::pair<OwnerTy, uint64_t>>;
 292   SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
 293   llvm::sort(Uses, [](const UseTy &L, const UseTy &R) {
 294     return L.second.second < R.second.second;
 295   });
 296   UseMap.clear();
 297   for (const auto &Pair : Uses) {
 298     auto Owner = Pair.second.first;
 299     if (!Owner)
 300       continue;
 301     if (Owner.is<MetadataAsValue *>())
 302       continue;
 303
 304     // Resolve MDNodes that point at this.
 305     auto *OwnerMD = dyn_cast<MDNode>(Owner.get<Metadata *>());
 306     if (!OwnerMD)
 307       continue;
 308     if (OwnerMD->isResolved())
 309       continue;
 310     OwnerMD->decrementUnresolvedOperandCount();
 311   }
 312 }
 313
 314 ReplaceableMetadataImpl *ReplaceableMetadataImpl::getOrCreate(Metadata &MD) {
 315   if (auto *N = dyn_cast<MDNode>(&MD))
 316     return N->isResolved() ? nullptr : N->Context.getOrCreateReplaceableUses();
 317   return dyn_cast<ValueAsMetadata>(&MD);
 318 }
 319
 320 ReplaceableMetadataImpl *ReplaceableMetadataImpl::getIfExists(Metadata &MD) {
 321   if (auto *N = dyn_cast<MDNode>(&MD))
 322     return N->isResolved() ? nullptr : N->Context.getReplaceableUses();
 323   return dyn_cast<ValueAsMetadata>(&MD);
 324 }
 325
 326 bool ReplaceableMetadataImpl::isReplaceable(const Metadata &MD) {
 327   if (auto *N = dyn_cast<MDNode>(&MD))
 328     return !N->isResolved();
 329   return dyn_cast<ValueAsMetadata>(&MD);
 330 }
 331
 332 static DISubprogram *getLocalFunctionMetadata(Value *V) {
 333   assert(V && "Expected value");
 334   if (auto *A = dyn_cast<Argument>(V)) {
 335     if (auto *Fn = A->getParent())
 336       return Fn->getSubprogram();
 337     return nullptr;
 338   }
 339
 340   if (BasicBlock *BB = cast<Instruction>(V)->getParent()) {
 341     if (auto *Fn = BB->getParent())
 342       return Fn->getSubprogram();
 343     return nullptr;
 344   }
 345
 346   return nullptr;
 347 }
 348
 349 ValueAsMetadata *ValueAsMetadata::get(Value *V) {
 350   assert(V && "Unexpected null Value");
 351
 352   auto &Context = V->getContext();
 353   auto *&Entry = Context.pImpl->ValuesAsMetadata[V];
 354   if (!Entry) {
 355     assert((isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) &&
 356            "Expected constant or function-local value");
 357     assert(!V->IsUsedByMD && "Expected this to be the only metadata use");
 358     V->IsUsedByMD = true;
 359     if (auto *C = dyn_cast<Constant>(V))
 360       Entry = new ConstantAsMetadata(C);
 361     else
 362       Entry = new LocalAsMetadata(V);
 363   }
 364
 365   return Entry;
 366 }
 367
 368 ValueAsMetadata *ValueAsMetadata::getIfExists(Value *V) {
 369   assert(V && "Unexpected null Value");
 370   return V->getContext().pImpl->ValuesAsMetadata.lookup(V);
 371 }
 372
 373 void ValueAsMetadata::handleDeletion(Value *V) {
 374   assert(V && "Expected valid value");
 375
 376   auto &Store = V->getType()->getContext().pImpl->ValuesAsMetadata;
 377   auto I = Store.find(V);
 378   if (I == Store.end())
 379     return;
 380
 381   // Remove old entry from the map.
 382   ValueAsMetadata *MD = I->second;
 383   assert(MD && "Expected valid metadata");
 384   assert(MD->getValue() == V && "Expected valid mapping");
 385   Store.erase(I);
 386
 387   // Delete the metadata.
 388   MD->replaceAllUsesWith(nullptr);
 389   delete MD;
 390 }
 391
 392 void ValueAsMetadata::handleRAUW(Value *From, Value *To) {
 393   assert(From && "Expected valid value");
 394   assert(To && "Expected valid value");
 395   assert(From != To && "Expected changed value");
 396   assert(From->getType() == To->getType() && "Unexpected type change");
 397
 398   LLVMContext &Context = From->getType()->getContext();
 399   auto &Store = Context.pImpl->ValuesAsMetadata;
 400   auto I = Store.find(From);
 401   if (I == Store.end()) {
 402     assert(!From->IsUsedByMD && "Expected From not to be used by metadata");
 403     return;
 404   }
 405
 406   // Remove old entry from the map.
 407   assert(From->IsUsedByMD && "Expected From to be used by metadata");
 408   From->IsUsedByMD = false;
 409   ValueAsMetadata *MD = I->second;
 410   assert(MD && "Expected valid metadata");
 411   assert(MD->getValue() == From && "Expected valid mapping");
 412   Store.erase(I);
 413
 414   if (isa<LocalAsMetadata>(MD)) {
 415     if (auto *C = dyn_cast<Constant>(To)) {
 416       // Local became a constant.
 417       MD->replaceAllUsesWith(ConstantAsMetadata::get(C));
 418       delete MD;
 419       return;
 420     }
 421     if (getLocalFunctionMetadata(From) && getLocalFunctionMetadata(To) &&
 422         getLocalFunctionMetadata(From) != getLocalFunctionMetadata(To)) {
 423       // DISubprogram changed.
 424       MD->replaceAllUsesWith(nullptr);
 425       delete MD;
 426       return;
 427     }
 428   } else if (!isa<Constant>(To)) {
 429     // Changed to function-local value.
 430     MD->replaceAllUsesWith(nullptr);
 431     delete MD;
 432     return;
 433   }
 434
 435   auto *&Entry = Store[To];
 436   if (Entry) {
 437     // The target already exists.
 438     MD->replaceAllUsesWith(Entry);
 439     delete MD;
 440     return;
 441   }
 442
 443   // Update MD in place (and update the map entry).
 444   assert(!To->IsUsedByMD && "Expected this to be the only metadata use");
 445   To->IsUsedByMD = true;
 446   MD->V = To;
 447   Entry = MD;
 448 }
 449
 450 //===----------------------------------------------------------------------===//
 451 // MDString implementation.
 452 //
 453
 454 MDString *MDString::get(LLVMContext &Context, StringRef Str) {
 455   auto &Store = Context.pImpl->MDStringCache;
 456   auto I = Store.try_emplace(Str);
 457   auto &MapEntry = I.first->getValue();
 458   if (!I.second)
 459     return &MapEntry;
 460   MapEntry.Entry = &*I.first;
 461   return &MapEntry;
 462 }
 463
 464 StringRef MDString::getString() const {
 465   assert(Entry && "Expected to find string map entry");
 466   return Entry->first();
 467 }
 468
 469 //===----------------------------------------------------------------------===//
 470 // MDNode implementation.
 471 //
 472
 473 // Assert that the MDNode types will not be unaligned by the objects
 474 // prepended to them.
 475 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 476   static_assert(                                                               \
 477       alignof(uint64_t) >= alignof(CLASS),                                     \
 478       "Alignment is insufficient after objects prepended to " #CLASS);
 479 #include "llvm/IR/Metadata.def"
 480
 481 void *MDNode::operator new(size_t Size, unsigned NumOps) {
 482   size_t OpSize = NumOps * sizeof(MDOperand);
 483   // uint64_t is the most aligned type we need support (ensured by static_assert
 484   // above)
 485   OpSize = alignTo(OpSize, alignof(uint64_t));
 486   void *Ptr = reinterpret_cast<char *>(::operator new(OpSize + Size)) + OpSize;
 487   MDOperand *O = static_cast<MDOperand *>(Ptr);
 488   for (MDOperand *E = O - NumOps; O != E; --O)
 489     (void)new (O - 1) MDOperand;
 490   return Ptr;
 491 }
 492
 493 void MDNode::operator delete(void *Mem) {
 494   MDNode *N = static_cast<MDNode *>(Mem);
 495   size_t OpSize = N->NumOperands * sizeof(MDOperand);
 496   OpSize = alignTo(OpSize, alignof(uint64_t));
 497
 498   MDOperand *O = static_cast<MDOperand *>(Mem);
 499   for (MDOperand *E = O - N->NumOperands; O != E; --O)
 500     (O - 1)->~MDOperand();
 501   ::operator delete(reinterpret_cast<char *>(Mem) - OpSize);
 502 }
 503
 504 MDNode::MDNode(LLVMContext &Context, unsigned ID, StorageType Storage,
 505                ArrayRef<Metadata *> Ops1, ArrayRef<Metadata *> Ops2)
 506     : Metadata(ID, Storage), NumOperands(Ops1.size() + Ops2.size()),
 507       NumUnresolved(0), Context(Context) {
 508   unsigned Op = 0;
 509   for (Metadata *MD : Ops1)
 510     setOperand(Op++, MD);
 511   for (Metadata *MD : Ops2)
 512     setOperand(Op++, MD);
 513
 514   if (!isUniqued())
 515     return;
 516
 517   // Count the unresolved operands.  If there are any, RAUW support will be
 518   // added lazily on first reference.
 519   countUnresolvedOperands();
 520 }
 521
 522 TempMDNode MDNode::clone() const {
 523   switch (getMetadataID()) {
 524   default:
 525     llvm_unreachable("Invalid MDNode subclass");
 526 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 527   case CLASS##Kind:                                                            \
 528     return cast<CLASS>(this)->cloneImpl();
 529 #include "llvm/IR/Metadata.def"
 530   }
 531 }
 532
 533 static bool isOperandUnresolved(Metadata *Op) {
 534   if (auto *N = dyn_cast_or_null<MDNode>(Op))
 535     return !N->isResolved();
 536   return false;
 537 }
 538
 539 void MDNode::countUnresolvedOperands() {
 540   assert(NumUnresolved == 0 && "Expected unresolved ops to be uncounted");
 541   assert(isUniqued() && "Expected this to be uniqued");
 542   NumUnresolved = count_if(operands(), isOperandUnresolved);
 543 }
 544
 545 void MDNode::makeUniqued() {
 546   assert(isTemporary() && "Expected this to be temporary");
 547   assert(!isResolved() && "Expected this to be unresolved");
 548
 549   // Enable uniquing callbacks.
 550   for (auto &Op : mutable_operands())
 551     Op.reset(Op.get(), this);
 552
 553   // Make this 'uniqued'.
 554   Storage = Uniqued;
 555   countUnresolvedOperands();
 556   if (!NumUnresolved) {
 557     dropReplaceableUses();
 558     assert(isResolved() && "Expected this to be resolved");
 559   }
 560
 561   assert(isUniqued() && "Expected this to be uniqued");
 562 }
 563
 564 void MDNode::makeDistinct() {
 565   assert(isTemporary() && "Expected this to be temporary");
 566   assert(!isResolved() && "Expected this to be unresolved");
 567
 568   // Drop RAUW support and store as a distinct node.
 569   dropReplaceableUses();
 570   storeDistinctInContext();
 571
 572   assert(isDistinct() && "Expected this to be distinct");
 573   assert(isResolved() && "Expected this to be resolved");
 574 }
 575
 576 void MDNode::resolve() {
 577   assert(isUniqued() && "Expected this to be uniqued");
 578   assert(!isResolved() && "Expected this to be unresolved");
 579
 580   NumUnresolved = 0;
 581   dropReplaceableUses();
 582
 583   assert(isResolved() && "Expected this to be resolved");
 584 }
 585
 586 void MDNode::dropReplaceableUses() {
 587   assert(!NumUnresolved && "Unexpected unresolved operand");
 588
 589   // Drop any RAUW support.
 590   if (Context.hasReplaceableUses())
 591     Context.takeReplaceableUses()->resolveAllUses();
 592 }
 593
 594 void MDNode::resolveAfterOperandChange(Metadata *Old, Metadata *New) {
 595   assert(isUniqued() && "Expected this to be uniqued");
 596   assert(NumUnresolved != 0 && "Expected unresolved operands");
 597
 598   // Check if an operand was resolved.
 599   if (!isOperandUnresolved(Old)) {
 600     if (isOperandUnresolved(New))
 601       // An operand was un-resolved!
 602       ++NumUnresolved;
 603   } else if (!isOperandUnresolved(New))
 604     decrementUnresolvedOperandCount();
 605 }
 606
 607 void MDNode::decrementUnresolvedOperandCount() {
 608   assert(!isResolved() && "Expected this to be unresolved");
 609   if (isTemporary())
 610     return;
 611
 612   assert(isUniqued() && "Expected this to be uniqued");
 613   if (--NumUnresolved)
 614     return;
 615
 616   // Last unresolved operand has just been resolved.
 617   dropReplaceableUses();
 618   assert(isResolved() && "Expected this to become resolved");
 619 }
 620
 621 void MDNode::resolveCycles() {
 622   if (isResolved())
 623     return;
 624
 625   // Resolve this node immediately.
 626   resolve();
 627
 628   // Resolve all operands.
 629   for (const auto &Op : operands()) {
 630     auto *N = dyn_cast_or_null<MDNode>(Op);
 631     if (!N)
 632       continue;
 633
 634     assert(!N->isTemporary() &&
 635            "Expected all forward declarations to be resolved");
 636     if (!N->isResolved())
 637       N->resolveCycles();
 638   }
 639 }
 640
 641 static bool hasSelfReference(MDNode *N) {
 642   for (Metadata *MD : N->operands())
 643     if (MD == N)
 644       return true;
 645   return false;
 646 }
 647
 648 MDNode *MDNode::replaceWithPermanentImpl() {
 649   switch (getMetadataID()) {
 650   default:
 651     // If this type isn't uniquable, replace with a distinct node.
 652     return replaceWithDistinctImpl();
 653
 654 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
 655   case CLASS##Kind:                                                            \
 656     break;
 657 #include "llvm/IR/Metadata.def"
 658   }
 659
 660   // Even if this type is uniquable, self-references have to be distinct.
 661   if (hasSelfReference(this))
 662     return replaceWithDistinctImpl();
 663   return replaceWithUniquedImpl();
 664 }
 665
 666 MDNode *MDNode::replaceWithUniquedImpl() {
 667   // Try to uniquify in place.
 668   MDNode *UniquedNode = uniquify();
 669
 670   if (UniquedNode == this) {
 671     makeUniqued();
 672     return this;
 673   }
 674
 675   // Collision, so RAUW instead.
 676   replaceAllUsesWith(UniquedNode);
 677   deleteAsSubclass();
 678   return UniquedNode;
 679 }
 680
 681 MDNode *MDNode::replaceWithDistinctImpl() {
 682   makeDistinct();
 683   return this;
 684 }
 685
 686 void MDTuple::recalculateHash() {
 687   setHash(MDTupleInfo::KeyTy::calculateHash(this));
 688 }
 689
 690 void MDNode::dropAllReferences() {
 691   for (unsigned I = 0, E = NumOperands; I != E; ++I)
 692     setOperand(I, nullptr);
 693   if (Context.hasReplaceableUses()) {
 694     Context.getReplaceableUses()->resolveAllUses(/* ResolveUsers */ false);
 695     (void)Context.takeReplaceableUses();
 696   }
 697 }
 698
 699 void MDNode::handleChangedOperand(void *Ref, Metadata *New) {
 700   unsigned Op = static_cast<MDOperand *>(Ref) - op_begin();
 701   assert(Op < getNumOperands() && "Expected valid operand");
 702
 703   if (!isUniqued()) {
 704     // This node is not uniqued.  Just set the operand and be done with it.
 705     setOperand(Op, New);
 706     return;
 707   }
 708
 709   // This node is uniqued.
 710   eraseFromStore();
 711
 712   Metadata *Old = getOperand(Op);
 713   setOperand(Op, New);
 714
 715   // Drop uniquing for self-reference cycles and deleted constants.
 716   if (New == this || (!New && Old && isa<ConstantAsMetadata>(Old))) {
 717     if (!isResolved())
 718       resolve();
 719     storeDistinctInContext();
 720     return;
 721   }
 722
 723   // Re-unique the node.
 724   auto *Uniqued = uniquify();
 725   if (Uniqued == this) {
 726     if (!isResolved())
 727       resolveAfterOperandChange(Old, New);
 728     return;
 729   }
 730
 731   // Collision.
 732   if (!isResolved()) {
 733     // Still unresolved, so RAUW.
 734     //
 735     // First, clear out all operands to prevent any recursion (similar to
 736     // dropAllReferences(), but we still need the use-list).
 737     for (unsigned O = 0, E = getNumOperands(); O != E; ++O)
 738       setOperand(O, nullptr);
 739     if (Context.hasReplaceableUses())
 740       Context.getReplaceableUses()->replaceAllUsesWith(Uniqued);
 741     deleteAsSubclass();
 742     return;
 743   }
 744
 745   // Store in non-uniqued form if RAUW isn't possible.
 746   storeDistinctInContext();
 747 }
 748
 749 void MDNode::deleteAsSubclass() {
 750   switch (getMetadataID()) {
 751   default:
 752     llvm_unreachable("Invalid subclass of MDNode");
 753 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 754   case CLASS##Kind:                                                            \
 755     delete cast<CLASS>(this);                                                  \
 756     break;
 757 #include "llvm/IR/Metadata.def"
 758   }
 759 }
 760
 761 template <class T, class InfoT>
 762 static T *uniquifyImpl(T *N, DenseSet<T *, InfoT> &Store) {
 763   if (T *U = getUniqued(Store, N))
 764     return U;
 765
 766   Store.insert(N);
 767   return N;
 768 }
 769
 770 template <class NodeTy> struct MDNode::HasCachedHash {
 771   using Yes = char[1];
 772   using No = char[2];
 773   template <class U, U Val> struct SFINAE {};
 774
 775   template <class U>
 776   static Yes &check(SFINAE<void (U::*)(unsigned), &U::setHash> *);
 777   template <class U> static No &check(...);
 778
 779   static const bool value = sizeof(check<NodeTy>(nullptr)) == sizeof(Yes);
 780 };
 781
 782 MDNode *MDNode::uniquify() {
 783   assert(!hasSelfReference(this) && "Cannot uniquify a self-referencing node");
 784
 785   // Try to insert into uniquing store.
 786   switch (getMetadataID()) {
 787   default:
 788     llvm_unreachable("Invalid or non-uniquable subclass of MDNode");
 789 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
 790   case CLASS##Kind: {                                                          \
 791     CLASS *SubclassThis = cast<CLASS>(this);                                   \
 792     std::integral_constant<bool, HasCachedHash<CLASS>::value>                  \
 793         ShouldRecalculateHash;                                                 \
 794     dispatchRecalculateHash(SubclassThis, ShouldRecalculateHash);              \
 795     return uniquifyImpl(SubclassThis, getContext().pImpl->CLASS##s);           \
 796   }
 797 #include "llvm/IR/Metadata.def"
 798   }
 799 }
 800
 801 void MDNode::eraseFromStore() {
 802   switch (getMetadataID()) {
 803   default:
 804     llvm_unreachable("Invalid or non-uniquable subclass of MDNode");
 805 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
 806   case CLASS##Kind:                                                            \
 807     getContext().pImpl->CLASS##s.erase(cast<CLASS>(this));                     \
 808     break;
 809 #include "llvm/IR/Metadata.def"
 810   }
 811 }
 812
 813 MDTuple *MDTuple::getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
 814                           StorageType Storage, bool ShouldCreate) {
 815   unsigned Hash = 0;
 816   if (Storage == Uniqued) {
 817     MDTupleInfo::KeyTy Key(MDs);
 818     if (auto *N = getUniqued(Context.pImpl->MDTuples, Key))
 819       return N;
 820     if (!ShouldCreate)
 821       return nullptr;
 822     Hash = Key.getHash();
 823   } else {
 824     assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
 825   }
 826
 827   return storeImpl(new (MDs.size()) MDTuple(Context, Storage, Hash, MDs),
 828                    Storage, Context.pImpl->MDTuples);
 829 }
 830
 831 void MDNode::deleteTemporary(MDNode *N) {
 832   assert(N->isTemporary() && "Expected temporary node");
 833   N->replaceAllUsesWith(nullptr);
 834   N->deleteAsSubclass();
 835 }
 836
 837 void MDNode::storeDistinctInContext() {
 838   assert(!Context.hasReplaceableUses() && "Unexpected replaceable uses");
 839   assert(!NumUnresolved && "Unexpected unresolved nodes");
 840   Storage = Distinct;
 841   assert(isResolved() && "Expected this to be resolved");
 842
 843   // Reset the hash.
 844   switch (getMetadataID()) {
 845   default:
 846     llvm_unreachable("Invalid subclass of MDNode");
 847 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 848   case CLASS##Kind: {                                                          \
 849     std::integral_constant<bool, HasCachedHash<CLASS>::value> ShouldResetHash; \
 850     dispatchResetHash(cast<CLASS>(this), ShouldResetHash);                     \
 851     break;                                                                     \
 852   }
 853 #include "llvm/IR/Metadata.def"
 854   }
 855
 856   getContext().pImpl->DistinctMDNodes.push_back(this);
 857 }
 858
 859 void MDNode::replaceOperandWith(unsigned I, Metadata *New) {
 860   if (getOperand(I) == New)
 861     return;
 862
 863   if (!isUniqued()) {
 864     setOperand(I, New);
 865     return;
 866   }
 867
 868   handleChangedOperand(mutable_begin() + I, New);
 869 }
 870
 871 void MDNode::setOperand(unsigned I, Metadata *New) {
 872   assert(I < NumOperands);
 873   mutable_begin()[I].reset(New, isUniqued() ? this : nullptr);
 874 }
 875
 876 /// Get a node or a self-reference that looks like it.
 877 ///
 878 /// Special handling for finding self-references, for use by \a
 879 /// MDNode::concatenate() and \a MDNode::intersect() to maintain behaviour from
 880 /// when self-referencing nodes were still uniqued.  If the first operand has
 881 /// the same operands as \c Ops, return the first operand instead.
 882 static MDNode *getOrSelfReference(LLVMContext &Context,
 883                                   ArrayRef<Metadata *> Ops) {
 884   if (!Ops.empty())
 885     if (MDNode *N = dyn_cast_or_null<MDNode>(Ops[0]))
 886       if (N->getNumOperands() == Ops.size() && N == N->getOperand(0)) {
 887         for (unsigned I = 1, E = Ops.size(); I != E; ++I)
 888           if (Ops[I] != N->getOperand(I))
 889             return MDNode::get(Context, Ops);
 890         return N;
 891       }
 892
 893   return MDNode::get(Context, Ops);
 894 }
 895
 896 MDNode *MDNode::concatenate(MDNode *A, MDNode *B) {
 897   if (!A)
 898     return B;
 899   if (!B)
 900     return A;
 901
 902   SmallSetVector<Metadata *, 4> MDs(A->op_begin(), A->op_end());
 903   MDs.insert(B->op_begin(), B->op_end());
 904
 905   // FIXME: This preserves long-standing behaviour, but is it really the right
 906   // behaviour?  Or was that an unintended side-effect of node uniquing?
 907   return getOrSelfReference(A->getContext(), MDs.getArrayRef());
 908 }
 909
 910 MDNode *MDNode::intersect(MDNode *A, MDNode *B) {
 911   if (!A || !B)
 912     return nullptr;
 913
 914   SmallSetVector<Metadata *, 4> MDs(A->op_begin(), A->op_end());
 915   SmallPtrSet<Metadata *, 4> BSet(B->op_begin(), B->op_end());
 916   MDs.remove_if([&](Metadata *MD) { return !is_contained(BSet, MD); });
 917
 918   // FIXME: This preserves long-standing behaviour, but is it really the right
 919   // behaviour?  Or was that an unintended side-effect of node uniquing?
 920   return getOrSelfReference(A->getContext(), MDs.getArrayRef());
 921 }
 922
 923 MDNode *MDNode::getMostGenericAliasScope(MDNode *A, MDNode *B) {
 924   if (!A || !B)
 925     return nullptr;
 926
 927   return concatenate(A, B);
 928 }
 929
 930 MDNode *MDNode::getMostGenericFPMath(MDNode *A, MDNode *B) {
 931   if (!A || !B)
 932     return nullptr;
 933
 934   APFloat AVal = mdconst::extract<ConstantFP>(A->getOperand(0))->getValueAPF();
 935   APFloat BVal = mdconst::extract<ConstantFP>(B->getOperand(0))->getValueAPF();
 936   if (AVal.compare(BVal) == APFloat::cmpLessThan)
 937     return A;
 938   return B;
 939 }
 940
 941 static bool isContiguous(const ConstantRange &A, const ConstantRange &B) {
 942   return A.getUpper() == B.getLower() || A.getLower() == B.getUpper();
 943 }
 944
 945 static bool canBeMerged(const ConstantRange &A, const ConstantRange &B) {
 946   return !A.intersectWith(B).isEmptySet() || isContiguous(A, B);
 947 }
 948
 949 static bool tryMergeRange(SmallVectorImpl<ConstantInt *> &EndPoints,
 950                           ConstantInt *Low, ConstantInt *High) {
 951   ConstantRange NewRange(Low->getValue(), High->getValue());
 952   unsigned Size = EndPoints.size();
 953   APInt LB = EndPoints[Size - 2]->getValue();
 954   APInt LE = EndPoints[Size - 1]->getValue();
 955   ConstantRange LastRange(LB, LE);
 956   if (canBeMerged(NewRange, LastRange)) {
 957     ConstantRange Union = LastRange.unionWith(NewRange);
 958     Type *Ty = High->getType();
 959     EndPoints[Size - 2] =
 960         cast<ConstantInt>(ConstantInt::get(Ty, Union.getLower()));
 961     EndPoints[Size - 1] =
 962         cast<ConstantInt>(ConstantInt::get(Ty, Union.getUpper()));
 963     return true;
 964   }
 965   return false;
 966 }
 967
 968 static void addRange(SmallVectorImpl<ConstantInt *> &EndPoints,
 969                      ConstantInt *Low, ConstantInt *High) {
 970   if (!EndPoints.empty())
 971     if (tryMergeRange(EndPoints, Low, High))
 972       return;
 973
 974   EndPoints.push_back(Low);
 975   EndPoints.push_back(High);
 976 }
 977
 978 MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
 979   // Given two ranges, we want to compute the union of the ranges. This
 980   // is slightly complicated by having to combine the intervals and merge
 981   // the ones that overlap.
 982
 983   if (!A || !B)
 984     return nullptr;
 985
 986   if (A == B)
 987     return A;
 988
 989   // First, walk both lists in order of the lower boundary of each interval.
 990   // At each step, try to merge the new interval to the last one we adedd.
 991   SmallVector<ConstantInt *, 4> EndPoints;
 992   int AI = 0;
 993   int BI = 0;
 994   int AN = A->getNumOperands() / 2;
 995   int BN = B->getNumOperands() / 2;
 996   while (AI < AN && BI < BN) {
 997     ConstantInt *ALow = mdconst::extract<ConstantInt>(A->getOperand(2 * AI));
 998     ConstantInt *BLow = mdconst::extract<ConstantInt>(B->getOperand(2 * BI));
 999
1000     if (ALow->getValue().slt(BLow->getValue())) {
1001       addRange(EndPoints, ALow,
1002                mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
1003       ++AI;
1004     } else {
1005       addRange(EndPoints, BLow,
1006                mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
1007       ++BI;
1008     }
1009   }
1010   while (AI < AN) {
1011     addRange(EndPoints, mdconst::extract<ConstantInt>(A->getOperand(2 * AI)),
1012              mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
1013     ++AI;
1014   }
1015   while (BI < BN) {
1016     addRange(EndPoints, mdconst::extract<ConstantInt>(B->getOperand(2 * BI)),
1017              mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
1018     ++BI;
1019   }
1020
1021   // If we have more than 2 ranges (4 endpoints) we have to try to merge
1022   // the last and first ones.
1023   unsigned Size = EndPoints.size();
1024   if (Size > 4) {
1025     ConstantInt *FB = EndPoints[0];
1026     ConstantInt *FE = EndPoints[1];
1027     if (tryMergeRange(EndPoints, FB, FE)) {
1028       for (unsigned i = 0; i < Size - 2; ++i) {
1029         EndPoints[i] = EndPoints[i + 2];
1030       }
1031       EndPoints.resize(Size - 2);
1032     }
1033   }
1034
1035   // If in the end we have a single range, it is possible that it is now the
1036   // full range. Just drop the metadata in that case.
1037   if (EndPoints.size() == 2) {
1038     ConstantRange Range(EndPoints[0]->getValue(), EndPoints[1]->getValue());
1039     if (Range.isFullSet())
1040       return nullptr;
1041   }
1042
1043   SmallVector<Metadata *, 4> MDs;
1044   MDs.reserve(EndPoints.size());
1045   for (auto *I : EndPoints)
1046     MDs.push_back(ConstantAsMetadata::get(I));
1047   return MDNode::get(A->getContext(), MDs);
1048 }
1049
1050 MDNode *MDNode::getMostGenericAlignmentOrDereferenceable(MDNode *A, MDNode *B) {
1051   if (!A || !B)
1052     return nullptr;
1053
1054   ConstantInt *AVal = mdconst::extract<ConstantInt>(A->getOperand(0));
1055   ConstantInt *BVal = mdconst::extract<ConstantInt>(B->getOperand(0));
1056   if (AVal->getZExtValue() < BVal->getZExtValue())
1057     return A;
1058   return B;
1059 }
1060
1061 //===----------------------------------------------------------------------===//
1062 // NamedMDNode implementation.
1063 //
1064
1065 static SmallVector<TrackingMDRef, 4> &getNMDOps(void *Operands) {
1066   return *(SmallVector<TrackingMDRef, 4> *)Operands;
1067 }
1068
1069 NamedMDNode::NamedMDNode(const Twine &N)
1070     : Name(N.str()), Operands(new SmallVector<TrackingMDRef, 4>()) {}
1071
1072 NamedMDNode::~NamedMDNode() {
1073   dropAllReferences();
1074   delete &getNMDOps(Operands);
1075 }
1076
1077 unsigned NamedMDNode::getNumOperands() const {
1078   return (unsigned)getNMDOps(Operands).size();
1079 }
1080
1081 MDNode *NamedMDNode::getOperand(unsigned i) const {
1082   assert(i < getNumOperands() && "Invalid Operand number!");
1083   auto *N = getNMDOps(Operands)[i].get();
1084   return cast_or_null<MDNode>(N);
1085 }
1086
1087 void NamedMDNode::addOperand(MDNode *M) { getNMDOps(Operands).emplace_back(M); }
1088
1089 void NamedMDNode::setOperand(unsigned I, MDNode *New) {
1090   assert(I < getNumOperands() && "Invalid operand number");
1091   getNMDOps(Operands)[I].reset(New);
1092 }
1093
1094 void NamedMDNode::eraseFromParent() { getParent()->eraseNamedMetadata(this); }
1095
1096 void NamedMDNode::clearOperands() { getNMDOps(Operands).clear(); }
1097
1098 StringRef NamedMDNode::getName() const { return StringRef(Name); }
1099
1100 //===----------------------------------------------------------------------===//
1101 // Instruction Metadata method implementations.
1102 //
1103 void MDAttachmentMap::set(unsigned ID, MDNode &MD) {
1104   for (auto &I : Attachments)
1105     if (I.first == ID) {
1106       I.second.reset(&MD);
1107       return;
1108     }
1109   Attachments.emplace_back(std::piecewise_construct, std::make_tuple(ID),
1110                            std::make_tuple(&MD));
1111 }
1112
1113 bool MDAttachmentMap::erase(unsigned ID) {
1114   if (empty())
1115     return false;
1116
1117   // Common case is one/last value.
1118   if (Attachments.back().first == ID) {
1119     Attachments.pop_back();
1120     return true;
1121   }
1122
1123   for (auto I = Attachments.begin(), E = std::prev(Attachments.end()); I != E;
1124        ++I)
1125     if (I->first == ID) {
1126       *I = std::move(Attachments.back());
1127       Attachments.pop_back();
1128       return true;
1129     }
1130
1131   return false;
1132 }
1133
1134 MDNode *MDAttachmentMap::lookup(unsigned ID) const {
1135   for (const auto &I : Attachments)
1136     if (I.first == ID)
1137       return I.second;
1138   return nullptr;
1139 }
1140
1141 void MDAttachmentMap::getAll(
1142     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1143   Result.append(Attachments.begin(), Attachments.end());
1144
1145   // Sort the resulting array so it is stable.
1146   if (Result.size() > 1)
1147     array_pod_sort(Result.begin(), Result.end());
1148 }
1149
1150 void MDGlobalAttachmentMap::insert(unsigned ID, MDNode &MD) {
1151   Attachments.push_back({ID, TrackingMDNodeRef(&MD)});
1152 }
1153
1154 MDNode *MDGlobalAttachmentMap::lookup(unsigned ID) const {
1155   for (const auto &A : Attachments)
1156     if (A.MDKind == ID)
1157       return A.Node;
1158   return nullptr;
1159 }
1160
1161 void MDGlobalAttachmentMap::get(unsigned ID,
1162                                 SmallVectorImpl<MDNode *> &Result) const {
1163   for (const auto &A : Attachments)
1164     if (A.MDKind == ID)
1165       Result.push_back(A.Node);
1166 }
1167
1168 bool MDGlobalAttachmentMap::erase(unsigned ID) {
1169   auto I = std::remove_if(Attachments.begin(), Attachments.end(),
1170                           [ID](const Attachment &A) { return A.MDKind == ID; });
1171   bool Changed = I != Attachments.end();
1172   Attachments.erase(I, Attachments.end());
1173   return Changed;
1174 }
1175
1176 void MDGlobalAttachmentMap::getAll(
1177     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1178   for (const auto &A : Attachments)
1179     Result.emplace_back(A.MDKind, A.Node);
1180
1181   // Sort the resulting array so it is stable with respect to metadata IDs. We
1182   // need to preserve the original insertion order though.
1183   std::stable_sort(
1184       Result.begin(), Result.end(),
1185       [](const std::pair<unsigned, MDNode *> &A,
1186          const std::pair<unsigned, MDNode *> &B) { return A.first < B.first; });
1187 }
1188
1189 void Instruction::setMetadata(StringRef Kind, MDNode *Node) {
1190   if (!Node && !hasMetadata())
1191     return;
1192   setMetadata(getContext().getMDKindID(Kind), Node);
1193 }
1194
1195 MDNode *Instruction::getMetadataImpl(StringRef Kind) const {
1196   return getMetadataImpl(getContext().getMDKindID(Kind));
1197 }
1198
1199 void Instruction::dropUnknownNonDebugMetadata(ArrayRef<unsigned> KnownIDs) {
1200   if (!hasMetadataHashEntry())
1201     return; // Nothing to remove!
1202
1203   auto &InstructionMetadata = getContext().pImpl->InstructionMetadata;
1204
1205   SmallSet<unsigned, 4> KnownSet;
1206   KnownSet.insert(KnownIDs.begin(), KnownIDs.end());
1207   if (KnownSet.empty()) {
1208     // Just drop our entry at the store.
1209     InstructionMetadata.erase(this);
1210     setHasMetadataHashEntry(false);
1211     return;
1212   }
1213
1214   auto &Info = InstructionMetadata[this];
1215   Info.remove_if([&KnownSet](const std::pair<unsigned, TrackingMDNodeRef> &I) {
1216     return !KnownSet.count(I.first);
1217   });
1218
1219   if (Info.empty()) {
1220     // Drop our entry at the store.
1221     InstructionMetadata.erase(this);
1222     setHasMetadataHashEntry(false);
1223   }
1224 }
1225
1226 void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
1227   if (!Node && !hasMetadata())
1228     return;
1229
1230   // Handle 'dbg' as a special case since it is not stored in the hash table.
1231   if (KindID == LLVMContext::MD_dbg) {
1232     DbgLoc = DebugLoc(Node);
1233     return;
1234   }
1235
1236   // Handle the case when we're adding/updating metadata on an instruction.
1237   if (Node) {
1238     auto &Info = getContext().pImpl->InstructionMetadata[this];
1239     assert(!Info.empty() == hasMetadataHashEntry() &&
1240            "HasMetadata bit is wonked");
1241     if (Info.empty())
1242       setHasMetadataHashEntry(true);
1243     Info.set(KindID, *Node);
1244     return;
1245   }
1246
1247   // Otherwise, we're removing metadata from an instruction.
1248   assert((hasMetadataHashEntry() ==
1249           (getContext().pImpl->InstructionMetadata.count(this) > 0)) &&
1250          "HasMetadata bit out of date!");
1251   if (!hasMetadataHashEntry())
1252     return; // Nothing to remove!
1253   auto &Info = getContext().pImpl->InstructionMetadata[this];
1254
1255   // Handle removal of an existing value.
1256   Info.erase(KindID);
1257
1258   if (!Info.empty())
1259     return;
1260
1261   getContext().pImpl->InstructionMetadata.erase(this);
1262   setHasMetadataHashEntry(false);
1263 }
1264
1265 void Instruction::setAAMetadata(const AAMDNodes &N) {
1266   setMetadata(LLVMContext::MD_tbaa, N.TBAA);
1267   setMetadata(LLVMContext::MD_alias_scope, N.Scope);
1268   setMetadata(LLVMContext::MD_noalias, N.NoAlias);
1269 }
1270
1271 MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
1272   // Handle 'dbg' as a special case since it is not stored in the hash table.
1273   if (KindID == LLVMContext::MD_dbg)
1274     return DbgLoc.getAsMDNode();
1275
1276   if (!hasMetadataHashEntry())
1277     return nullptr;
1278   auto &Info = getContext().pImpl->InstructionMetadata[this];
1279   assert(!Info.empty() && "bit out of sync with hash table");
1280
1281   return Info.lookup(KindID);
1282 }
1283
1284 void Instruction::getAllMetadataImpl(
1285     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1286   Result.clear();
1287
1288   // Handle 'dbg' as a special case since it is not stored in the hash table.
1289   if (DbgLoc) {
1290     Result.push_back(
1291         std::make_pair((unsigned)LLVMContext::MD_dbg, DbgLoc.getAsMDNode()));
1292     if (!hasMetadataHashEntry())
1293       return;
1294   }
1295
1296   assert(hasMetadataHashEntry() &&
1297          getContext().pImpl->InstructionMetadata.count(this) &&
1298          "Shouldn't have called this");
1299   const auto &Info = getContext().pImpl->InstructionMetadata.find(this)->second;
1300   assert(!Info.empty() && "Shouldn't have called this");
1301   Info.getAll(Result);
1302 }
1303
1304 void Instruction::getAllMetadataOtherThanDebugLocImpl(
1305     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1306   Result.clear();
1307   assert(hasMetadataHashEntry() &&
1308          getContext().pImpl->InstructionMetadata.count(this) &&
1309          "Shouldn't have called this");
1310   const auto &Info = getContext().pImpl->InstructionMetadata.find(this)->second;
1311   assert(!Info.empty() && "Shouldn't have called this");
1312   Info.getAll(Result);
1313 }
1314
1315 bool Instruction::extractProfMetadata(uint64_t &TrueVal,
1316                                       uint64_t &FalseVal) const {
1317   assert(
1318       (getOpcode() == Instruction::Br || getOpcode() == Instruction::Select) &&
1319       "Looking for branch weights on something besides branch or select");
1320
1321   auto *ProfileData = getMetadata(LLVMContext::MD_prof);
1322   if (!ProfileData || ProfileData->getNumOperands() != 3)
1323     return false;
1324
1325   auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
1326   if (!ProfDataName || !ProfDataName->getString().equals("branch_weights"))
1327     return false;
1328
1329   auto *CITrue = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1));
1330   auto *CIFalse = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2));
1331   if (!CITrue || !CIFalse)
1332     return false;
1333
1334   TrueVal = CITrue->getValue().getZExtValue();
1335   FalseVal = CIFalse->getValue().getZExtValue();
1336
1337   return true;
1338 }
1339
1340 bool Instruction::extractProfTotalWeight(uint64_t &TotalVal) const {
1341   assert((getOpcode() == Instruction::Br ||
1342           getOpcode() == Instruction::Select ||
1343           getOpcode() == Instruction::Call ||
1344           getOpcode() == Instruction::Invoke ||
1345           getOpcode() == Instruction::Switch) &&
1346          "Looking for branch weights on something besides branch");
1347
1348   TotalVal = 0;
1349   auto *ProfileData = getMetadata(LLVMContext::MD_prof);
1350   if (!ProfileData)
1351     return false;
1352
1353   auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
1354   if (!ProfDataName)
1355     return false;
1356
1357   if (ProfDataName->getString().equals("branch_weights")) {
1358     TotalVal = 0;
1359     for (unsigned i = 1; i < ProfileData->getNumOperands(); i++) {
1360       auto *V = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i));
1361       if (!V)
1362         return false;
1363       TotalVal += V->getValue().getZExtValue();
1364     }
1365     return true;
1366   } else if (ProfDataName->getString().equals("VP") &&
1367              ProfileData->getNumOperands() > 3) {
1368     TotalVal = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2))
1369                    ->getValue()
1370                    .getZExtValue();
1371     return true;
1372   }
1373   return false;
1374 }
1375
1376 void Instruction::clearMetadataHashEntries() {
1377   assert(hasMetadataHashEntry() && "Caller should check");
1378   getContext().pImpl->InstructionMetadata.erase(this);
1379   setHasMetadataHashEntry(false);
1380 }
1381
1382 void GlobalObject::getMetadata(unsigned KindID,
1383                                SmallVectorImpl<MDNode *> &MDs) const {
1384   if (hasMetadata())
1385     getContext().pImpl->GlobalObjectMetadata[this].get(KindID, MDs);
1386 }
1387
1388 void GlobalObject::getMetadata(StringRef Kind,
1389                                SmallVectorImpl<MDNode *> &MDs) const {
1390   if (hasMetadata())
1391     getMetadata(getContext().getMDKindID(Kind), MDs);
1392 }
1393
1394 void GlobalObject::addMetadata(unsigned KindID, MDNode &MD) {
1395   if (!hasMetadata())
1396     setHasMetadataHashEntry(true);
1397
1398   getContext().pImpl->GlobalObjectMetadata[this].insert(KindID, MD);
1399 }
1400
1401 void GlobalObject::addMetadata(StringRef Kind, MDNode &MD) {
1402   addMetadata(getContext().getMDKindID(Kind), MD);
1403 }
1404
1405 bool GlobalObject::eraseMetadata(unsigned KindID) {
1406   // Nothing to unset.
1407   if (!hasMetadata())
1408     return false;
1409
1410   auto &Store = getContext().pImpl->GlobalObjectMetadata[this];
1411   bool Changed = Store.erase(KindID);
1412   if (Store.empty())
1413     clearMetadata();
1414   return Changed;
1415 }
1416
1417 void GlobalObject::getAllMetadata(
1418     SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const {
1419   MDs.clear();
1420
1421   if (!hasMetadata())
1422     return;
1423
1424   getContext().pImpl->GlobalObjectMetadata[this].getAll(MDs);
1425 }
1426
1427 void GlobalObject::clearMetadata() {
1428   if (!hasMetadata())
1429     return;
1430   getContext().pImpl->GlobalObjectMetadata.erase(this);
1431   setHasMetadataHashEntry(false);
1432 }
1433
1434 void GlobalObject::setMetadata(unsigned KindID, MDNode *N) {
1435   eraseMetadata(KindID);
1436   if (N)
1437     addMetadata(KindID, *N);
1438 }
1439
1440 void GlobalObject::setMetadata(StringRef Kind, MDNode *N) {
1441   setMetadata(getContext().getMDKindID(Kind), N);
1442 }
1443
1444 MDNode *GlobalObject::getMetadata(unsigned KindID) const {
1445   if (hasMetadata())
1446     return getContext().pImpl->GlobalObjectMetadata[this].lookup(KindID);
1447   return nullptr;
1448 }
1449
1450 MDNode *GlobalObject::getMetadata(StringRef Kind) const {
1451   return getMetadata(getContext().getMDKindID(Kind));
1452 }
1453
1454 void GlobalObject::copyMetadata(const GlobalObject *Other, unsigned Offset) {
1455   SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
1456   Other->getAllMetadata(MDs);
1457   for (auto &MD : MDs) {
1458     // We need to adjust the type metadata offset.
1459     if (Offset != 0 && MD.first == LLVMContext::MD_type) {
1460       auto *OffsetConst = cast<ConstantInt>(
1461           cast<ConstantAsMetadata>(MD.second->getOperand(0))->getValue());
1462       Metadata *TypeId = MD.second->getOperand(1);
1463       auto *NewOffsetMD = ConstantAsMetadata::get(ConstantInt::get(
1464           OffsetConst->getType(), OffsetConst->getValue() + Offset));
1465       addMetadata(LLVMContext::MD_type,
1466                   *MDNode::get(getContext(), {NewOffsetMD, TypeId}));
1467       continue;
1468     }
1469     // If an offset adjustment was specified we need to modify the DIExpression
1470     // to prepend the adjustment:
1471     // !DIExpression(DW_OP_plus, Offset, [original expr])
1472     auto *Attachment = MD.second;
1473     if (Offset != 0 && MD.first == LLVMContext::MD_dbg) {
1474       DIGlobalVariable *GV = dyn_cast<DIGlobalVariable>(Attachment);
1475       DIExpression *E = nullptr;
1476       if (!GV) {
1477         auto *GVE = cast<DIGlobalVariableExpression>(Attachment);
1478         GV = GVE->getVariable();
1479         E = GVE->getExpression();
1480       }
1481       ArrayRef<uint64_t> OrigElements;
1482       if (E)
1483         OrigElements = E->getElements();
1484       std::vector<uint64_t> Elements(OrigElements.size() + 2);
1485       Elements[0] = dwarf::DW_OP_plus_uconst;
1486       Elements[1] = Offset;
1487       std::copy(OrigElements.begin(), OrigElements.end(), Elements.begin() + 2);
1488       E = DIExpression::get(getContext(), Elements);
1489       Attachment = DIGlobalVariableExpression::get(getContext(), GV, E);
1490     }
1491     addMetadata(MD.first, *Attachment);
1492   }
1493 }
1494
1495 void GlobalObject::addTypeMetadata(unsigned Offset, Metadata *TypeID) {
1496   addMetadata(
1497       LLVMContext::MD_type,
1498       *MDTuple::get(getContext(),
1499                     {ConstantAsMetadata::get(ConstantInt::get(
1500                          Type::getInt64Ty(getContext()), Offset)),
1501                      TypeID}));
1502 }
1503
1504 void Function::setSubprogram(DISubprogram *SP) {
1505   setMetadata(LLVMContext::MD_dbg, SP);
1506 }
1507
1508 DISubprogram *Function::getSubprogram() const {
1509   return cast_or_null<DISubprogram>(getMetadata(LLVMContext::MD_dbg));
1510 }
1511
1512 bool Function::isDebugInfoForProfiling() const {
1513   if (DISubprogram *SP = getSubprogram()) {
1514     if (DICompileUnit *CU = SP->getUnit()) {
1515       return CU->getDebugInfoForProfiling();
1516     }
1517   }
1518   return false;
1519 }
1520
1521 void GlobalVariable::addDebugInfo(DIGlobalVariableExpression *GV) {
1522   addMetadata(LLVMContext::MD_dbg, *GV);
1523 }
1524
1525 void GlobalVariable::getDebugInfo(
1526     SmallVectorImpl<DIGlobalVariableExpression *> &GVs) const {
1527   SmallVector<MDNode *, 1> MDs;
1528   getMetadata(LLVMContext::MD_dbg, MDs);
1529   for (MDNode *MD : MDs)
1530     GVs.push_back(cast<DIGlobalVariableExpression>(MD));
1531 }