lib/IR/Metadata.cpp

   1 //===- Metadata.cpp - Implement Metadata classes --------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the Metadata classes.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "LLVMContextImpl.h"
  14 #include "MetadataImpl.h"
  15 #include "SymbolTableListTraitsImpl.h"
  16 #include "llvm/ADT/APFloat.h"
  17 #include "llvm/ADT/APInt.h"
  18 #include "llvm/ADT/ArrayRef.h"
  19 #include "llvm/ADT/DenseSet.h"
  20 #include "llvm/ADT/None.h"
  21 #include "llvm/ADT/STLExtras.h"
  22 #include "llvm/ADT/SetVector.h"
  23 #include "llvm/ADT/SmallPtrSet.h"
  24 #include "llvm/ADT/SmallSet.h"
  25 #include "llvm/ADT/SmallVector.h"
  26 #include "llvm/ADT/StringMap.h"
  27 #include "llvm/ADT/StringRef.h"
  28 #include "llvm/ADT/Twine.h"
  29 #include "llvm/IR/Argument.h"
  30 #include "llvm/IR/BasicBlock.h"
  31 #include "llvm/IR/Constant.h"
  32 #include "llvm/IR/ConstantRange.h"
  33 #include "llvm/IR/Constants.h"
  34 #include "llvm/IR/DebugInfoMetadata.h"
  35 #include "llvm/IR/DebugLoc.h"
  36 #include "llvm/IR/Function.h"
  37 #include "llvm/IR/GlobalObject.h"
  38 #include "llvm/IR/GlobalVariable.h"
  39 #include "llvm/IR/Instruction.h"
  40 #include "llvm/IR/LLVMContext.h"
  41 #include "llvm/IR/Metadata.h"
  42 #include "llvm/IR/Module.h"
  43 #include "llvm/IR/TrackingMDRef.h"
  44 #include "llvm/IR/Type.h"
  45 #include "llvm/IR/Value.h"
  46 #include "llvm/IR/ValueHandle.h"
  47 #include "llvm/Support/Casting.h"
  48 #include "llvm/Support/ErrorHandling.h"
  49 #include "llvm/Support/MathExtras.h"
  50 #include <algorithm>
  51 #include <cassert>
  52 #include <cstddef>
  53 #include <cstdint>
  54 #include <iterator>
  55 #include <tuple>
  56 #include <type_traits>
  57 #include <utility>
  58 #include <vector>
  59
  60 using namespace llvm;
  61
  62 MetadataAsValue::MetadataAsValue(Type *Ty, Metadata *MD)
  63     : Value(Ty, MetadataAsValueVal), MD(MD) {
  64   track();
  65 }
  66
  67 MetadataAsValue::~MetadataAsValue() {
  68   getType()->getContext().pImpl->MetadataAsValues.erase(MD);
  69   untrack();
  70 }
  71
  72 /// Canonicalize metadata arguments to intrinsics.
  73 ///
  74 /// To support bitcode upgrades (and assembly semantic sugar) for \a
  75 /// MetadataAsValue, we need to canonicalize certain metadata.
  76 ///
  77 ///   - nullptr is replaced by an empty MDNode.
  78 ///   - An MDNode with a single null operand is replaced by an empty MDNode.
  79 ///   - An MDNode whose only operand is a \a ConstantAsMetadata gets skipped.
  80 ///
  81 /// This maintains readability of bitcode from when metadata was a type of
  82 /// value, and these bridges were unnecessary.
  83 static Metadata *canonicalizeMetadataForValue(LLVMContext &Context,
  84                                               Metadata *MD) {
  85   if (!MD)
  86     // !{}
  87     return MDNode::get(Context, None);
  88
  89   // Return early if this isn't a single-operand MDNode.
  90   auto *N = dyn_cast<MDNode>(MD);
  91   if (!N || N->getNumOperands() != 1)
  92     return MD;
  93
  94   if (!N->getOperand(0))
  95     // !{}
  96     return MDNode::get(Context, None);
  97
  98   if (auto *C = dyn_cast<ConstantAsMetadata>(N->getOperand(0)))
  99     // Look through the MDNode.
 100     return C;
 101
 102   return MD;
 103 }
 104
 105 MetadataAsValue *MetadataAsValue::get(LLVMContext &Context, Metadata *MD) {
 106   MD = canonicalizeMetadataForValue(Context, MD);
 107   auto *&Entry = Context.pImpl->MetadataAsValues[MD];
 108   if (!Entry)
 109     Entry = new MetadataAsValue(Type::getMetadataTy(Context), MD);
 110   return Entry;
 111 }
 112
 113 MetadataAsValue *MetadataAsValue::getIfExists(LLVMContext &Context,
 114                                               Metadata *MD) {
 115   MD = canonicalizeMetadataForValue(Context, MD);
 116   auto &Store = Context.pImpl->MetadataAsValues;
 117   return Store.lookup(MD);
 118 }
 119
 120 void MetadataAsValue::handleChangedMetadata(Metadata *MD) {
 121   LLVMContext &Context = getContext();
 122   MD = canonicalizeMetadataForValue(Context, MD);
 123   auto &Store = Context.pImpl->MetadataAsValues;
 124
 125   // Stop tracking the old metadata.
 126   Store.erase(this->MD);
 127   untrack();
 128   this->MD = nullptr;
 129
 130   // Start tracking MD, or RAUW if necessary.
 131   auto *&Entry = Store[MD];
 132   if (Entry) {
 133     replaceAllUsesWith(Entry);
 134     delete this;
 135     return;
 136   }
 137
 138   this->MD = MD;
 139   track();
 140   Entry = this;
 141 }
 142
 143 void MetadataAsValue::track() {
 144   if (MD)
 145     MetadataTracking::track(&MD, *MD, *this);
 146 }
 147
 148 void MetadataAsValue::untrack() {
 149   if (MD)
 150     MetadataTracking::untrack(MD);
 151 }
 152
 153 bool MetadataTracking::track(void *Ref, Metadata &MD, OwnerTy Owner) {
 154   assert(Ref && "Expected live reference");
 155   assert((Owner || *static_cast<Metadata **>(Ref) == &MD) &&
 156          "Reference without owner must be direct");
 157   if (auto *R = ReplaceableMetadataImpl::getOrCreate(MD)) {
 158     R->addRef(Ref, Owner);
 159     return true;
 160   }
 161   if (auto *PH = dyn_cast<DistinctMDOperandPlaceholder>(&MD)) {
 162     assert(!PH->Use && "Placeholders can only be used once");
 163     assert(!Owner && "Unexpected callback to owner");
 164     PH->Use = static_cast<Metadata **>(Ref);
 165     return true;
 166   }
 167   return false;
 168 }
 169
 170 void MetadataTracking::untrack(void *Ref, Metadata &MD) {
 171   assert(Ref && "Expected live reference");
 172   if (auto *R = ReplaceableMetadataImpl::getIfExists(MD))
 173     R->dropRef(Ref);
 174   else if (auto *PH = dyn_cast<DistinctMDOperandPlaceholder>(&MD))
 175     PH->Use = nullptr;
 176 }
 177
 178 bool MetadataTracking::retrack(void *Ref, Metadata &MD, void *New) {
 179   assert(Ref && "Expected live reference");
 180   assert(New && "Expected live reference");
 181   assert(Ref != New && "Expected change");
 182   if (auto *R = ReplaceableMetadataImpl::getIfExists(MD)) {
 183     R->moveRef(Ref, New, MD);
 184     return true;
 185   }
 186   assert(!isa<DistinctMDOperandPlaceholder>(MD) &&
 187          "Unexpected move of an MDOperand");
 188   assert(!isReplaceable(MD) &&
 189          "Expected un-replaceable metadata, since we didn't move a reference");
 190   return false;
 191 }
 192
 193 bool MetadataTracking::isReplaceable(const Metadata &MD) {
 194   return ReplaceableMetadataImpl::isReplaceable(MD);
 195 }
 196
 197 void ReplaceableMetadataImpl::addRef(void *Ref, OwnerTy Owner) {
 198   bool WasInserted =
 199       UseMap.insert(std::make_pair(Ref, std::make_pair(Owner, NextIndex)))
 200           .second;
 201   (void)WasInserted;
 202   assert(WasInserted && "Expected to add a reference");
 203
 204   ++NextIndex;
 205   assert(NextIndex != 0 && "Unexpected overflow");
 206 }
 207
 208 void ReplaceableMetadataImpl::dropRef(void *Ref) {
 209   bool WasErased = UseMap.erase(Ref);
 210   (void)WasErased;
 211   assert(WasErased && "Expected to drop a reference");
 212 }
 213
 214 void ReplaceableMetadataImpl::moveRef(void *Ref, void *New,
 215                                       const Metadata &MD) {
 216   auto I = UseMap.find(Ref);
 217   assert(I != UseMap.end() && "Expected to move a reference");
 218   auto OwnerAndIndex = I->second;
 219   UseMap.erase(I);
 220   bool WasInserted = UseMap.insert(std::make_pair(New, OwnerAndIndex)).second;
 221   (void)WasInserted;
 222   assert(WasInserted && "Expected to add a reference");
 223
 224   // Check that the references are direct if there's no owner.
 225   (void)MD;
 226   assert((OwnerAndIndex.first || *static_cast<Metadata **>(Ref) == &MD) &&
 227          "Reference without owner must be direct");
 228   assert((OwnerAndIndex.first || *static_cast<Metadata **>(New) == &MD) &&
 229          "Reference without owner must be direct");
 230 }
 231
 232 void ReplaceableMetadataImpl::replaceAllUsesWith(Metadata *MD) {
 233   if (UseMap.empty())
 234     return;
 235
 236   // Copy out uses since UseMap will get touched below.
 237   using UseTy = std::pair<void *, std::pair<OwnerTy, uint64_t>>;
 238   SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
 239   llvm::sort(Uses, [](const UseTy &L, const UseTy &R) {
 240     return L.second.second < R.second.second;
 241   });
 242   for (const auto &Pair : Uses) {
 243     // Check that this Ref hasn't disappeared after RAUW (when updating a
 244     // previous Ref).
 245     if (!UseMap.count(Pair.first))
 246       continue;
 247
 248     OwnerTy Owner = Pair.second.first;
 249     if (!Owner) {
 250       // Update unowned tracking references directly.
 251       Metadata *&Ref = *static_cast<Metadata **>(Pair.first);
 252       Ref = MD;
 253       if (MD)
 254         MetadataTracking::track(Ref);
 255       UseMap.erase(Pair.first);
 256       continue;
 257     }
 258
 259     // Check for MetadataAsValue.
 260     if (Owner.is<MetadataAsValue *>()) {
 261       Owner.get<MetadataAsValue *>()->handleChangedMetadata(MD);
 262       continue;
 263     }
 264
 265     // There's a Metadata owner -- dispatch.
 266     Metadata *OwnerMD = Owner.get<Metadata *>();
 267     switch (OwnerMD->getMetadataID()) {
 268 #define HANDLE_METADATA_LEAF(CLASS)                                            \
 269   case Metadata::CLASS##Kind:                                                  \
 270     cast<CLASS>(OwnerMD)->handleChangedOperand(Pair.first, MD);                \
 271     continue;
 272 #include "llvm/IR/Metadata.def"
 273     default:
 274       llvm_unreachable("Invalid metadata subclass");
 275     }
 276   }
 277   assert(UseMap.empty() && "Expected all uses to be replaced");
 278 }
 279
 280 void ReplaceableMetadataImpl::resolveAllUses(bool ResolveUsers) {
 281   if (UseMap.empty())
 282     return;
 283
 284   if (!ResolveUsers) {
 285     UseMap.clear();
 286     return;
 287   }
 288
 289   // Copy out uses since UseMap could get touched below.
 290   using UseTy = std::pair<void *, std::pair<OwnerTy, uint64_t>>;
 291   SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
 292   llvm::sort(Uses, [](const UseTy &L, const UseTy &R) {
 293     return L.second.second < R.second.second;
 294   });
 295   UseMap.clear();
 296   for (const auto &Pair : Uses) {
 297     auto Owner = Pair.second.first;
 298     if (!Owner)
 299       continue;
 300     if (Owner.is<MetadataAsValue *>())
 301       continue;
 302
 303     // Resolve MDNodes that point at this.
 304     auto *OwnerMD = dyn_cast<MDNode>(Owner.get<Metadata *>());
 305     if (!OwnerMD)
 306       continue;
 307     if (OwnerMD->isResolved())
 308       continue;
 309     OwnerMD->decrementUnresolvedOperandCount();
 310   }
 311 }
 312
 313 ReplaceableMetadataImpl *ReplaceableMetadataImpl::getOrCreate(Metadata &MD) {
 314   if (auto *N = dyn_cast<MDNode>(&MD))
 315     return N->isResolved() ? nullptr : N->Context.getOrCreateReplaceableUses();
 316   return dyn_cast<ValueAsMetadata>(&MD);
 317 }
 318
 319 ReplaceableMetadataImpl *ReplaceableMetadataImpl::getIfExists(Metadata &MD) {
 320   if (auto *N = dyn_cast<MDNode>(&MD))
 321     return N->isResolved() ? nullptr : N->Context.getReplaceableUses();
 322   return dyn_cast<ValueAsMetadata>(&MD);
 323 }
 324
 325 bool ReplaceableMetadataImpl::isReplaceable(const Metadata &MD) {
 326   if (auto *N = dyn_cast<MDNode>(&MD))
 327     return !N->isResolved();
 328   return dyn_cast<ValueAsMetadata>(&MD);
 329 }
 330
 331 static DISubprogram *getLocalFunctionMetadata(Value *V) {
 332   assert(V && "Expected value");
 333   if (auto *A = dyn_cast<Argument>(V)) {
 334     if (auto *Fn = A->getParent())
 335       return Fn->getSubprogram();
 336     return nullptr;
 337   }
 338
 339   if (BasicBlock *BB = cast<Instruction>(V)->getParent()) {
 340     if (auto *Fn = BB->getParent())
 341       return Fn->getSubprogram();
 342     return nullptr;
 343   }
 344
 345   return nullptr;
 346 }
 347
 348 ValueAsMetadata *ValueAsMetadata::get(Value *V) {
 349   assert(V && "Unexpected null Value");
 350
 351   auto &Context = V->getContext();
 352   auto *&Entry = Context.pImpl->ValuesAsMetadata[V];
 353   if (!Entry) {
 354     assert((isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) &&
 355            "Expected constant or function-local value");
 356     assert(!V->IsUsedByMD && "Expected this to be the only metadata use");
 357     V->IsUsedByMD = true;
 358     if (auto *C = dyn_cast<Constant>(V))
 359       Entry = new ConstantAsMetadata(C);
 360     else
 361       Entry = new LocalAsMetadata(V);
 362   }
 363
 364   return Entry;
 365 }
 366
 367 ValueAsMetadata *ValueAsMetadata::getIfExists(Value *V) {
 368   assert(V && "Unexpected null Value");
 369   return V->getContext().pImpl->ValuesAsMetadata.lookup(V);
 370 }
 371
 372 void ValueAsMetadata::handleDeletion(Value *V) {
 373   assert(V && "Expected valid value");
 374
 375   auto &Store = V->getType()->getContext().pImpl->ValuesAsMetadata;
 376   auto I = Store.find(V);
 377   if (I == Store.end())
 378     return;
 379
 380   // Remove old entry from the map.
 381   ValueAsMetadata *MD = I->second;
 382   assert(MD && "Expected valid metadata");
 383   assert(MD->getValue() == V && "Expected valid mapping");
 384   Store.erase(I);
 385
 386   // Delete the metadata.
 387   MD->replaceAllUsesWith(nullptr);
 388   delete MD;
 389 }
 390
 391 void ValueAsMetadata::handleRAUW(Value *From, Value *To) {
 392   assert(From && "Expected valid value");
 393   assert(To && "Expected valid value");
 394   assert(From != To && "Expected changed value");
 395   assert(From->getType() == To->getType() && "Unexpected type change");
 396
 397   LLVMContext &Context = From->getType()->getContext();
 398   auto &Store = Context.pImpl->ValuesAsMetadata;
 399   auto I = Store.find(From);
 400   if (I == Store.end()) {
 401     assert(!From->IsUsedByMD && "Expected From not to be used by metadata");
 402     return;
 403   }
 404
 405   // Remove old entry from the map.
 406   assert(From->IsUsedByMD && "Expected From to be used by metadata");
 407   From->IsUsedByMD = false;
 408   ValueAsMetadata *MD = I->second;
 409   assert(MD && "Expected valid metadata");
 410   assert(MD->getValue() == From && "Expected valid mapping");
 411   Store.erase(I);
 412
 413   if (isa<LocalAsMetadata>(MD)) {
 414     if (auto *C = dyn_cast<Constant>(To)) {
 415       // Local became a constant.
 416       MD->replaceAllUsesWith(ConstantAsMetadata::get(C));
 417       delete MD;
 418       return;
 419     }
 420     if (getLocalFunctionMetadata(From) && getLocalFunctionMetadata(To) &&
 421         getLocalFunctionMetadata(From) != getLocalFunctionMetadata(To)) {
 422       // DISubprogram changed.
 423       MD->replaceAllUsesWith(nullptr);
 424       delete MD;
 425       return;
 426     }
 427   } else if (!isa<Constant>(To)) {
 428     // Changed to function-local value.
 429     MD->replaceAllUsesWith(nullptr);
 430     delete MD;
 431     return;
 432   }
 433
 434   auto *&Entry = Store[To];
 435   if (Entry) {
 436     // The target already exists.
 437     MD->replaceAllUsesWith(Entry);
 438     delete MD;
 439     return;
 440   }
 441
 442   // Update MD in place (and update the map entry).
 443   assert(!To->IsUsedByMD && "Expected this to be the only metadata use");
 444   To->IsUsedByMD = true;
 445   MD->V = To;
 446   Entry = MD;
 447 }
 448
 449 //===----------------------------------------------------------------------===//
 450 // MDString implementation.
 451 //
 452
 453 MDString *MDString::get(LLVMContext &Context, StringRef Str) {
 454   auto &Store = Context.pImpl->MDStringCache;
 455   auto I = Store.try_emplace(Str);
 456   auto &MapEntry = I.first->getValue();
 457   if (!I.second)
 458     return &MapEntry;
 459   MapEntry.Entry = &*I.first;
 460   return &MapEntry;
 461 }
 462
 463 StringRef MDString::getString() const {
 464   assert(Entry && "Expected to find string map entry");
 465   return Entry->first();
 466 }
 467
 468 //===----------------------------------------------------------------------===//
 469 // MDNode implementation.
 470 //
 471
 472 // Assert that the MDNode types will not be unaligned by the objects
 473 // prepended to them.
 474 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 475   static_assert(                                                               \
 476       alignof(uint64_t) >= alignof(CLASS),                                     \
 477       "Alignment is insufficient after objects prepended to " #CLASS);
 478 #include "llvm/IR/Metadata.def"
 479
 480 void *MDNode::operator new(size_t Size, unsigned NumOps) {
 481   size_t OpSize = NumOps * sizeof(MDOperand);
 482   // uint64_t is the most aligned type we need support (ensured by static_assert
 483   // above)
 484   OpSize = alignTo(OpSize, alignof(uint64_t));
 485   void *Ptr = reinterpret_cast<char *>(::operator new(OpSize + Size)) + OpSize;
 486   MDOperand *O = static_cast<MDOperand *>(Ptr);
 487   for (MDOperand *E = O - NumOps; O != E; --O)
 488     (void)new (O - 1) MDOperand;
 489   return Ptr;
 490 }
 491
 492 void MDNode::operator delete(void *Mem) {
 493   MDNode *N = static_cast<MDNode *>(Mem);
 494   size_t OpSize = N->NumOperands * sizeof(MDOperand);
 495   OpSize = alignTo(OpSize, alignof(uint64_t));
 496
 497   MDOperand *O = static_cast<MDOperand *>(Mem);
 498   for (MDOperand *E = O - N->NumOperands; O != E; --O)
 499     (O - 1)->~MDOperand();
 500   ::operator delete(reinterpret_cast<char *>(Mem) - OpSize);
 501 }
 502
 503 MDNode::MDNode(LLVMContext &Context, unsigned ID, StorageType Storage,
 504                ArrayRef<Metadata *> Ops1, ArrayRef<Metadata *> Ops2)
 505     : Metadata(ID, Storage), NumOperands(Ops1.size() + Ops2.size()),
 506       NumUnresolved(0), Context(Context) {
 507   unsigned Op = 0;
 508   for (Metadata *MD : Ops1)
 509     setOperand(Op++, MD);
 510   for (Metadata *MD : Ops2)
 511     setOperand(Op++, MD);
 512
 513   if (!isUniqued())
 514     return;
 515
 516   // Count the unresolved operands.  If there are any, RAUW support will be
 517   // added lazily on first reference.
 518   countUnresolvedOperands();
 519 }
 520
 521 TempMDNode MDNode::clone() const {
 522   switch (getMetadataID()) {
 523   default:
 524     llvm_unreachable("Invalid MDNode subclass");
 525 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 526   case CLASS##Kind:                                                            \
 527     return cast<CLASS>(this)->cloneImpl();
 528 #include "llvm/IR/Metadata.def"
 529   }
 530 }
 531
 532 static bool isOperandUnresolved(Metadata *Op) {
 533   if (auto *N = dyn_cast_or_null<MDNode>(Op))
 534     return !N->isResolved();
 535   return false;
 536 }
 537
 538 void MDNode::countUnresolvedOperands() {
 539   assert(NumUnresolved == 0 && "Expected unresolved ops to be uncounted");
 540   assert(isUniqued() && "Expected this to be uniqued");
 541   NumUnresolved = count_if(operands(), isOperandUnresolved);
 542 }
 543
 544 void MDNode::makeUniqued() {
 545   assert(isTemporary() && "Expected this to be temporary");
 546   assert(!isResolved() && "Expected this to be unresolved");
 547
 548   // Enable uniquing callbacks.
 549   for (auto &Op : mutable_operands())
 550     Op.reset(Op.get(), this);
 551
 552   // Make this 'uniqued'.
 553   Storage = Uniqued;
 554   countUnresolvedOperands();
 555   if (!NumUnresolved) {
 556     dropReplaceableUses();
 557     assert(isResolved() && "Expected this to be resolved");
 558   }
 559
 560   assert(isUniqued() && "Expected this to be uniqued");
 561 }
 562
 563 void MDNode::makeDistinct() {
 564   assert(isTemporary() && "Expected this to be temporary");
 565   assert(!isResolved() && "Expected this to be unresolved");
 566
 567   // Drop RAUW support and store as a distinct node.
 568   dropReplaceableUses();
 569   storeDistinctInContext();
 570
 571   assert(isDistinct() && "Expected this to be distinct");
 572   assert(isResolved() && "Expected this to be resolved");
 573 }
 574
 575 void MDNode::resolve() {
 576   assert(isUniqued() && "Expected this to be uniqued");
 577   assert(!isResolved() && "Expected this to be unresolved");
 578
 579   NumUnresolved = 0;
 580   dropReplaceableUses();
 581
 582   assert(isResolved() && "Expected this to be resolved");
 583 }
 584
 585 void MDNode::dropReplaceableUses() {
 586   assert(!NumUnresolved && "Unexpected unresolved operand");
 587
 588   // Drop any RAUW support.
 589   if (Context.hasReplaceableUses())
 590     Context.takeReplaceableUses()->resolveAllUses();
 591 }
 592
 593 void MDNode::resolveAfterOperandChange(Metadata *Old, Metadata *New) {
 594   assert(isUniqued() && "Expected this to be uniqued");
 595   assert(NumUnresolved != 0 && "Expected unresolved operands");
 596
 597   // Check if an operand was resolved.
 598   if (!isOperandUnresolved(Old)) {
 599     if (isOperandUnresolved(New))
 600       // An operand was un-resolved!
 601       ++NumUnresolved;
 602   } else if (!isOperandUnresolved(New))
 603     decrementUnresolvedOperandCount();
 604 }
 605
 606 void MDNode::decrementUnresolvedOperandCount() {
 607   assert(!isResolved() && "Expected this to be unresolved");
 608   if (isTemporary())
 609     return;
 610
 611   assert(isUniqued() && "Expected this to be uniqued");
 612   if (--NumUnresolved)
 613     return;
 614
 615   // Last unresolved operand has just been resolved.
 616   dropReplaceableUses();
 617   assert(isResolved() && "Expected this to become resolved");
 618 }
 619
 620 void MDNode::resolveCycles() {
 621   if (isResolved())
 622     return;
 623
 624   // Resolve this node immediately.
 625   resolve();
 626
 627   // Resolve all operands.
 628   for (const auto &Op : operands()) {
 629     auto *N = dyn_cast_or_null<MDNode>(Op);
 630     if (!N)
 631       continue;
 632
 633     assert(!N->isTemporary() &&
 634            "Expected all forward declarations to be resolved");
 635     if (!N->isResolved())
 636       N->resolveCycles();
 637   }
 638 }
 639
 640 static bool hasSelfReference(MDNode *N) {
 641   for (Metadata *MD : N->operands())
 642     if (MD == N)
 643       return true;
 644   return false;
 645 }
 646
 647 MDNode *MDNode::replaceWithPermanentImpl() {
 648   switch (getMetadataID()) {
 649   default:
 650     // If this type isn't uniquable, replace with a distinct node.
 651     return replaceWithDistinctImpl();
 652
 653 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
 654   case CLASS##Kind:                                                            \
 655     break;
 656 #include "llvm/IR/Metadata.def"
 657   }
 658
 659   // Even if this type is uniquable, self-references have to be distinct.
 660   if (hasSelfReference(this))
 661     return replaceWithDistinctImpl();
 662   return replaceWithUniquedImpl();
 663 }
 664
 665 MDNode *MDNode::replaceWithUniquedImpl() {
 666   // Try to uniquify in place.
 667   MDNode *UniquedNode = uniquify();
 668
 669   if (UniquedNode == this) {
 670     makeUniqued();
 671     return this;
 672   }
 673
 674   // Collision, so RAUW instead.
 675   replaceAllUsesWith(UniquedNode);
 676   deleteAsSubclass();
 677   return UniquedNode;
 678 }
 679
 680 MDNode *MDNode::replaceWithDistinctImpl() {
 681   makeDistinct();
 682   return this;
 683 }
 684
 685 void MDTuple::recalculateHash() {
 686   setHash(MDTupleInfo::KeyTy::calculateHash(this));
 687 }
 688
 689 void MDNode::dropAllReferences() {
 690   for (unsigned I = 0, E = NumOperands; I != E; ++I)
 691     setOperand(I, nullptr);
 692   if (Context.hasReplaceableUses()) {
 693     Context.getReplaceableUses()->resolveAllUses(/* ResolveUsers */ false);
 694     (void)Context.takeReplaceableUses();
 695   }
 696 }
 697
 698 void MDNode::handleChangedOperand(void *Ref, Metadata *New) {
 699   unsigned Op = static_cast<MDOperand *>(Ref) - op_begin();
 700   assert(Op < getNumOperands() && "Expected valid operand");
 701
 702   if (!isUniqued()) {
 703     // This node is not uniqued.  Just set the operand and be done with it.
 704     setOperand(Op, New);
 705     return;
 706   }
 707
 708   // This node is uniqued.
 709   eraseFromStore();
 710
 711   Metadata *Old = getOperand(Op);
 712   setOperand(Op, New);
 713
 714   // Drop uniquing for self-reference cycles and deleted constants.
 715   if (New == this || (!New && Old && isa<ConstantAsMetadata>(Old))) {
 716     if (!isResolved())
 717       resolve();
 718     storeDistinctInContext();
 719     return;
 720   }
 721
 722   // Re-unique the node.
 723   auto *Uniqued = uniquify();
 724   if (Uniqued == this) {
 725     if (!isResolved())
 726       resolveAfterOperandChange(Old, New);
 727     return;
 728   }
 729
 730   // Collision.
 731   if (!isResolved()) {
 732     // Still unresolved, so RAUW.
 733     //
 734     // First, clear out all operands to prevent any recursion (similar to
 735     // dropAllReferences(), but we still need the use-list).
 736     for (unsigned O = 0, E = getNumOperands(); O != E; ++O)
 737       setOperand(O, nullptr);
 738     if (Context.hasReplaceableUses())
 739       Context.getReplaceableUses()->replaceAllUsesWith(Uniqued);
 740     deleteAsSubclass();
 741     return;
 742   }
 743
 744   // Store in non-uniqued form if RAUW isn't possible.
 745   storeDistinctInContext();
 746 }
 747
 748 void MDNode::deleteAsSubclass() {
 749   switch (getMetadataID()) {
 750   default:
 751     llvm_unreachable("Invalid subclass of MDNode");
 752 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 753   case CLASS##Kind:                                                            \
 754     delete cast<CLASS>(this);                                                  \
 755     break;
 756 #include "llvm/IR/Metadata.def"
 757   }
 758 }
 759
 760 template <class T, class InfoT>
 761 static T *uniquifyImpl(T *N, DenseSet<T *, InfoT> &Store) {
 762   if (T *U = getUniqued(Store, N))
 763     return U;
 764
 765   Store.insert(N);
 766   return N;
 767 }
 768
 769 template <class NodeTy> struct MDNode::HasCachedHash {
 770   using Yes = char[1];
 771   using No = char[2];
 772   template <class U, U Val> struct SFINAE {};
 773
 774   template <class U>
 775   static Yes &check(SFINAE<void (U::*)(unsigned), &U::setHash> *);
 776   template <class U> static No &check(...);
 777
 778   static const bool value = sizeof(check<NodeTy>(nullptr)) == sizeof(Yes);
 779 };
 780
 781 MDNode *MDNode::uniquify() {
 782   assert(!hasSelfReference(this) && "Cannot uniquify a self-referencing node");
 783
 784   // Try to insert into uniquing store.
 785   switch (getMetadataID()) {
 786   default:
 787     llvm_unreachable("Invalid or non-uniquable subclass of MDNode");
 788 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
 789   case CLASS##Kind: {                                                          \
 790     CLASS *SubclassThis = cast<CLASS>(this);                                   \
 791     std::integral_constant<bool, HasCachedHash<CLASS>::value>                  \
 792         ShouldRecalculateHash;                                                 \
 793     dispatchRecalculateHash(SubclassThis, ShouldRecalculateHash);              \
 794     return uniquifyImpl(SubclassThis, getContext().pImpl->CLASS##s);           \
 795   }
 796 #include "llvm/IR/Metadata.def"
 797   }
 798 }
 799
 800 void MDNode::eraseFromStore() {
 801   switch (getMetadataID()) {
 802   default:
 803     llvm_unreachable("Invalid or non-uniquable subclass of MDNode");
 804 #define HANDLE_MDNODE_LEAF_UNIQUABLE(CLASS)                                    \
 805   case CLASS##Kind:                                                            \
 806     getContext().pImpl->CLASS##s.erase(cast<CLASS>(this));                     \
 807     break;
 808 #include "llvm/IR/Metadata.def"
 809   }
 810 }
 811
 812 MDTuple *MDTuple::getImpl(LLVMContext &Context, ArrayRef<Metadata *> MDs,
 813                           StorageType Storage, bool ShouldCreate) {
 814   unsigned Hash = 0;
 815   if (Storage == Uniqued) {
 816     MDTupleInfo::KeyTy Key(MDs);
 817     if (auto *N = getUniqued(Context.pImpl->MDTuples, Key))
 818       return N;
 819     if (!ShouldCreate)
 820       return nullptr;
 821     Hash = Key.getHash();
 822   } else {
 823     assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
 824   }
 825
 826   return storeImpl(new (MDs.size()) MDTuple(Context, Storage, Hash, MDs),
 827                    Storage, Context.pImpl->MDTuples);
 828 }
 829
 830 void MDNode::deleteTemporary(MDNode *N) {
 831   assert(N->isTemporary() && "Expected temporary node");
 832   N->replaceAllUsesWith(nullptr);
 833   N->deleteAsSubclass();
 834 }
 835
 836 void MDNode::storeDistinctInContext() {
 837   assert(!Context.hasReplaceableUses() && "Unexpected replaceable uses");
 838   assert(!NumUnresolved && "Unexpected unresolved nodes");
 839   Storage = Distinct;
 840   assert(isResolved() && "Expected this to be resolved");
 841
 842   // Reset the hash.
 843   switch (getMetadataID()) {
 844   default:
 845     llvm_unreachable("Invalid subclass of MDNode");
 846 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 847   case CLASS##Kind: {                                                          \
 848     std::integral_constant<bool, HasCachedHash<CLASS>::value> ShouldResetHash; \
 849     dispatchResetHash(cast<CLASS>(this), ShouldResetHash);                     \
 850     break;                                                                     \
 851   }
 852 #include "llvm/IR/Metadata.def"
 853   }
 854
 855   getContext().pImpl->DistinctMDNodes.push_back(this);
 856 }
 857
 858 void MDNode::replaceOperandWith(unsigned I, Metadata *New) {
 859   if (getOperand(I) == New)
 860     return;
 861
 862   if (!isUniqued()) {
 863     setOperand(I, New);
 864     return;
 865   }
 866
 867   handleChangedOperand(mutable_begin() + I, New);
 868 }
 869
 870 void MDNode::setOperand(unsigned I, Metadata *New) {
 871   assert(I < NumOperands);
 872   mutable_begin()[I].reset(New, isUniqued() ? this : nullptr);
 873 }
 874
 875 /// Get a node or a self-reference that looks like it.
 876 ///
 877 /// Special handling for finding self-references, for use by \a
 878 /// MDNode::concatenate() and \a MDNode::intersect() to maintain behaviour from
 879 /// when self-referencing nodes were still uniqued.  If the first operand has
 880 /// the same operands as \c Ops, return the first operand instead.
 881 static MDNode *getOrSelfReference(LLVMContext &Context,
 882                                   ArrayRef<Metadata *> Ops) {
 883   if (!Ops.empty())
 884     if (MDNode *N = dyn_cast_or_null<MDNode>(Ops[0]))
 885       if (N->getNumOperands() == Ops.size() && N == N->getOperand(0)) {
 886         for (unsigned I = 1, E = Ops.size(); I != E; ++I)
 887           if (Ops[I] != N->getOperand(I))
 888             return MDNode::get(Context, Ops);
 889         return N;
 890       }
 891
 892   return MDNode::get(Context, Ops);
 893 }
 894
 895 MDNode *MDNode::concatenate(MDNode *A, MDNode *B) {
 896   if (!A)
 897     return B;
 898   if (!B)
 899     return A;
 900
 901   SmallSetVector<Metadata *, 4> MDs(A->op_begin(), A->op_end());
 902   MDs.insert(B->op_begin(), B->op_end());
 903
 904   // FIXME: This preserves long-standing behaviour, but is it really the right
 905   // behaviour?  Or was that an unintended side-effect of node uniquing?
 906   return getOrSelfReference(A->getContext(), MDs.getArrayRef());
 907 }
 908
 909 MDNode *MDNode::intersect(MDNode *A, MDNode *B) {
 910   if (!A || !B)
 911     return nullptr;
 912
 913   SmallSetVector<Metadata *, 4> MDs(A->op_begin(), A->op_end());
 914   SmallPtrSet<Metadata *, 4> BSet(B->op_begin(), B->op_end());
 915   MDs.remove_if([&](Metadata *MD) { return !is_contained(BSet, MD); });
 916
 917   // FIXME: This preserves long-standing behaviour, but is it really the right
 918   // behaviour?  Or was that an unintended side-effect of node uniquing?
 919   return getOrSelfReference(A->getContext(), MDs.getArrayRef());
 920 }
 921
 922 MDNode *MDNode::getMostGenericAliasScope(MDNode *A, MDNode *B) {
 923   if (!A || !B)
 924     return nullptr;
 925
 926   return concatenate(A, B);
 927 }
 928
 929 MDNode *MDNode::getMostGenericFPMath(MDNode *A, MDNode *B) {
 930   if (!A || !B)
 931     return nullptr;
 932
 933   APFloat AVal = mdconst::extract<ConstantFP>(A->getOperand(0))->getValueAPF();
 934   APFloat BVal = mdconst::extract<ConstantFP>(B->getOperand(0))->getValueAPF();
 935   if (AVal.compare(BVal) == APFloat::cmpLessThan)
 936     return A;
 937   return B;
 938 }
 939
 940 static bool isContiguous(const ConstantRange &A, const ConstantRange &B) {
 941   return A.getUpper() == B.getLower() || A.getLower() == B.getUpper();
 942 }
 943
 944 static bool canBeMerged(const ConstantRange &A, const ConstantRange &B) {
 945   return !A.intersectWith(B).isEmptySet() || isContiguous(A, B);
 946 }
 947
 948 static bool tryMergeRange(SmallVectorImpl<ConstantInt *> &EndPoints,
 949                           ConstantInt *Low, ConstantInt *High) {
 950   ConstantRange NewRange(Low->getValue(), High->getValue());
 951   unsigned Size = EndPoints.size();
 952   APInt LB = EndPoints[Size - 2]->getValue();
 953   APInt LE = EndPoints[Size - 1]->getValue();
 954   ConstantRange LastRange(LB, LE);
 955   if (canBeMerged(NewRange, LastRange)) {
 956     ConstantRange Union = LastRange.unionWith(NewRange);
 957     Type *Ty = High->getType();
 958     EndPoints[Size - 2] =
 959         cast<ConstantInt>(ConstantInt::get(Ty, Union.getLower()));
 960     EndPoints[Size - 1] =
 961         cast<ConstantInt>(ConstantInt::get(Ty, Union.getUpper()));
 962     return true;
 963   }
 964   return false;
 965 }
 966
 967 static void addRange(SmallVectorImpl<ConstantInt *> &EndPoints,
 968                      ConstantInt *Low, ConstantInt *High) {
 969   if (!EndPoints.empty())
 970     if (tryMergeRange(EndPoints, Low, High))
 971       return;
 972
 973   EndPoints.push_back(Low);
 974   EndPoints.push_back(High);
 975 }
 976
 977 MDNode *MDNode::getMostGenericRange(MDNode *A, MDNode *B) {
 978   // Given two ranges, we want to compute the union of the ranges. This
 979   // is slightly complicated by having to combine the intervals and merge
 980   // the ones that overlap.
 981
 982   if (!A || !B)
 983     return nullptr;
 984
 985   if (A == B)
 986     return A;
 987
 988   // First, walk both lists in order of the lower boundary of each interval.
 989   // At each step, try to merge the new interval to the last one we adedd.
 990   SmallVector<ConstantInt *, 4> EndPoints;
 991   int AI = 0;
 992   int BI = 0;
 993   int AN = A->getNumOperands() / 2;
 994   int BN = B->getNumOperands() / 2;
 995   while (AI < AN && BI < BN) {
 996     ConstantInt *ALow = mdconst::extract<ConstantInt>(A->getOperand(2 * AI));
 997     ConstantInt *BLow = mdconst::extract<ConstantInt>(B->getOperand(2 * BI));
 998
 999     if (ALow->getValue().slt(BLow->getValue())) {
1000       addRange(EndPoints, ALow,
1001                mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
1002       ++AI;
1003     } else {
1004       addRange(EndPoints, BLow,
1005                mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
1006       ++BI;
1007     }
1008   }
1009   while (AI < AN) {
1010     addRange(EndPoints, mdconst::extract<ConstantInt>(A->getOperand(2 * AI)),
1011              mdconst::extract<ConstantInt>(A->getOperand(2 * AI + 1)));
1012     ++AI;
1013   }
1014   while (BI < BN) {
1015     addRange(EndPoints, mdconst::extract<ConstantInt>(B->getOperand(2 * BI)),
1016              mdconst::extract<ConstantInt>(B->getOperand(2 * BI + 1)));
1017     ++BI;
1018   }
1019
1020   // If we have more than 2 ranges (4 endpoints) we have to try to merge
1021   // the last and first ones.
1022   unsigned Size = EndPoints.size();
1023   if (Size > 4) {
1024     ConstantInt *FB = EndPoints[0];
1025     ConstantInt *FE = EndPoints[1];
1026     if (tryMergeRange(EndPoints, FB, FE)) {
1027       for (unsigned i = 0; i < Size - 2; ++i) {
1028         EndPoints[i] = EndPoints[i + 2];
1029       }
1030       EndPoints.resize(Size - 2);
1031     }
1032   }
1033
1034   // If in the end we have a single range, it is possible that it is now the
1035   // full range. Just drop the metadata in that case.
1036   if (EndPoints.size() == 2) {
1037     ConstantRange Range(EndPoints[0]->getValue(), EndPoints[1]->getValue());
1038     if (Range.isFullSet())
1039       return nullptr;
1040   }
1041
1042   SmallVector<Metadata *, 4> MDs;
1043   MDs.reserve(EndPoints.size());
1044   for (auto *I : EndPoints)
1045     MDs.push_back(ConstantAsMetadata::get(I));
1046   return MDNode::get(A->getContext(), MDs);
1047 }
1048
1049 MDNode *MDNode::getMostGenericAlignmentOrDereferenceable(MDNode *A, MDNode *B) {
1050   if (!A || !B)
1051     return nullptr;
1052
1053   ConstantInt *AVal = mdconst::extract<ConstantInt>(A->getOperand(0));
1054   ConstantInt *BVal = mdconst::extract<ConstantInt>(B->getOperand(0));
1055   if (AVal->getZExtValue() < BVal->getZExtValue())
1056     return A;
1057   return B;
1058 }
1059
1060 //===----------------------------------------------------------------------===//
1061 // NamedMDNode implementation.
1062 //
1063
1064 static SmallVector<TrackingMDRef, 4> &getNMDOps(void *Operands) {
1065   return *(SmallVector<TrackingMDRef, 4> *)Operands;
1066 }
1067
1068 NamedMDNode::NamedMDNode(const Twine &N)
1069     : Name(N.str()), Operands(new SmallVector<TrackingMDRef, 4>()) {}
1070
1071 NamedMDNode::~NamedMDNode() {
1072   dropAllReferences();
1073   delete &getNMDOps(Operands);
1074 }
1075
1076 unsigned NamedMDNode::getNumOperands() const {
1077   return (unsigned)getNMDOps(Operands).size();
1078 }
1079
1080 MDNode *NamedMDNode::getOperand(unsigned i) const {
1081   assert(i < getNumOperands() && "Invalid Operand number!");
1082   auto *N = getNMDOps(Operands)[i].get();
1083   return cast_or_null<MDNode>(N);
1084 }
1085
1086 void NamedMDNode::addOperand(MDNode *M) { getNMDOps(Operands).emplace_back(M); }
1087
1088 void NamedMDNode::setOperand(unsigned I, MDNode *New) {
1089   assert(I < getNumOperands() && "Invalid operand number");
1090   getNMDOps(Operands)[I].reset(New);
1091 }
1092
1093 void NamedMDNode::eraseFromParent() { getParent()->eraseNamedMetadata(this); }
1094
1095 void NamedMDNode::clearOperands() { getNMDOps(Operands).clear(); }
1096
1097 StringRef NamedMDNode::getName() const { return StringRef(Name); }
1098
1099 //===----------------------------------------------------------------------===//
1100 // Instruction Metadata method implementations.
1101 //
1102 void MDAttachmentMap::set(unsigned ID, MDNode &MD) {
1103   for (auto &I : Attachments)
1104     if (I.first == ID) {
1105       I.second.reset(&MD);
1106       return;
1107     }
1108   Attachments.emplace_back(std::piecewise_construct, std::make_tuple(ID),
1109                            std::make_tuple(&MD));
1110 }
1111
1112 bool MDAttachmentMap::erase(unsigned ID) {
1113   if (empty())
1114     return false;
1115
1116   // Common case is one/last value.
1117   if (Attachments.back().first == ID) {
1118     Attachments.pop_back();
1119     return true;
1120   }
1121
1122   for (auto I = Attachments.begin(), E = std::prev(Attachments.end()); I != E;
1123        ++I)
1124     if (I->first == ID) {
1125       *I = std::move(Attachments.back());
1126       Attachments.pop_back();
1127       return true;
1128     }
1129
1130   return false;
1131 }
1132
1133 MDNode *MDAttachmentMap::lookup(unsigned ID) const {
1134   for (const auto &I : Attachments)
1135     if (I.first == ID)
1136       return I.second;
1137   return nullptr;
1138 }
1139
1140 void MDAttachmentMap::getAll(
1141     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1142   Result.append(Attachments.begin(), Attachments.end());
1143
1144   // Sort the resulting array so it is stable.
1145   if (Result.size() > 1)
1146     array_pod_sort(Result.begin(), Result.end());
1147 }
1148
1149 void MDGlobalAttachmentMap::insert(unsigned ID, MDNode &MD) {
1150   Attachments.push_back({ID, TrackingMDNodeRef(&MD)});
1151 }
1152
1153 MDNode *MDGlobalAttachmentMap::lookup(unsigned ID) const {
1154   for (const auto &A : Attachments)
1155     if (A.MDKind == ID)
1156       return A.Node;
1157   return nullptr;
1158 }
1159
1160 void MDGlobalAttachmentMap::get(unsigned ID,
1161                                 SmallVectorImpl<MDNode *> &Result) const {
1162   for (const auto &A : Attachments)
1163     if (A.MDKind == ID)
1164       Result.push_back(A.Node);
1165 }
1166
1167 bool MDGlobalAttachmentMap::erase(unsigned ID) {
1168   auto I = std::remove_if(Attachments.begin(), Attachments.end(),
1169                           [ID](const Attachment &A) { return A.MDKind == ID; });
1170   bool Changed = I != Attachments.end();
1171   Attachments.erase(I, Attachments.end());
1172   return Changed;
1173 }
1174
1175 void MDGlobalAttachmentMap::getAll(
1176     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1177   for (const auto &A : Attachments)
1178     Result.emplace_back(A.MDKind, A.Node);
1179
1180   // Sort the resulting array so it is stable with respect to metadata IDs. We
1181   // need to preserve the original insertion order though.
1182   llvm::stable_sort(Result, less_first());
1183 }
1184
1185 void Instruction::setMetadata(StringRef Kind, MDNode *Node) {
1186   if (!Node && !hasMetadata())
1187     return;
1188   setMetadata(getContext().getMDKindID(Kind), Node);
1189 }
1190
1191 MDNode *Instruction::getMetadataImpl(StringRef Kind) const {
1192   return getMetadataImpl(getContext().getMDKindID(Kind));
1193 }
1194
1195 void Instruction::dropUnknownNonDebugMetadata(ArrayRef<unsigned> KnownIDs) {
1196   if (!hasMetadataHashEntry())
1197     return; // Nothing to remove!
1198
1199   auto &InstructionMetadata = getContext().pImpl->InstructionMetadata;
1200
1201   SmallSet<unsigned, 4> KnownSet;
1202   KnownSet.insert(KnownIDs.begin(), KnownIDs.end());
1203   if (KnownSet.empty()) {
1204     // Just drop our entry at the store.
1205     InstructionMetadata.erase(this);
1206     setHasMetadataHashEntry(false);
1207     return;
1208   }
1209
1210   auto &Info = InstructionMetadata[this];
1211   Info.remove_if([&KnownSet](const std::pair<unsigned, TrackingMDNodeRef> &I) {
1212     return !KnownSet.count(I.first);
1213   });
1214
1215   if (Info.empty()) {
1216     // Drop our entry at the store.
1217     InstructionMetadata.erase(this);
1218     setHasMetadataHashEntry(false);
1219   }
1220 }
1221
1222 void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
1223   if (!Node && !hasMetadata())
1224     return;
1225
1226   // Handle 'dbg' as a special case since it is not stored in the hash table.
1227   if (KindID == LLVMContext::MD_dbg) {
1228     DbgLoc = DebugLoc(Node);
1229     return;
1230   }
1231
1232   // Handle the case when we're adding/updating metadata on an instruction.
1233   if (Node) {
1234     auto &Info = getContext().pImpl->InstructionMetadata[this];
1235     assert(!Info.empty() == hasMetadataHashEntry() &&
1236            "HasMetadata bit is wonked");
1237     if (Info.empty())
1238       setHasMetadataHashEntry(true);
1239     Info.set(KindID, *Node);
1240     return;
1241   }
1242
1243   // Otherwise, we're removing metadata from an instruction.
1244   assert((hasMetadataHashEntry() ==
1245           (getContext().pImpl->InstructionMetadata.count(this) > 0)) &&
1246          "HasMetadata bit out of date!");
1247   if (!hasMetadataHashEntry())
1248     return; // Nothing to remove!
1249   auto &Info = getContext().pImpl->InstructionMetadata[this];
1250
1251   // Handle removal of an existing value.
1252   Info.erase(KindID);
1253
1254   if (!Info.empty())
1255     return;
1256
1257   getContext().pImpl->InstructionMetadata.erase(this);
1258   setHasMetadataHashEntry(false);
1259 }
1260
1261 void Instruction::setAAMetadata(const AAMDNodes &N) {
1262   setMetadata(LLVMContext::MD_tbaa, N.TBAA);
1263   setMetadata(LLVMContext::MD_alias_scope, N.Scope);
1264   setMetadata(LLVMContext::MD_noalias, N.NoAlias);
1265 }
1266
1267 MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
1268   // Handle 'dbg' as a special case since it is not stored in the hash table.
1269   if (KindID == LLVMContext::MD_dbg)
1270     return DbgLoc.getAsMDNode();
1271
1272   if (!hasMetadataHashEntry())
1273     return nullptr;
1274   auto &Info = getContext().pImpl->InstructionMetadata[this];
1275   assert(!Info.empty() && "bit out of sync with hash table");
1276
1277   return Info.lookup(KindID);
1278 }
1279
1280 void Instruction::getAllMetadataImpl(
1281     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1282   Result.clear();
1283
1284   // Handle 'dbg' as a special case since it is not stored in the hash table.
1285   if (DbgLoc) {
1286     Result.push_back(
1287         std::make_pair((unsigned)LLVMContext::MD_dbg, DbgLoc.getAsMDNode()));
1288     if (!hasMetadataHashEntry())
1289       return;
1290   }
1291
1292   assert(hasMetadataHashEntry() &&
1293          getContext().pImpl->InstructionMetadata.count(this) &&
1294          "Shouldn't have called this");
1295   const auto &Info = getContext().pImpl->InstructionMetadata.find(this)->second;
1296   assert(!Info.empty() && "Shouldn't have called this");
1297   Info.getAll(Result);
1298 }
1299
1300 void Instruction::getAllMetadataOtherThanDebugLocImpl(
1301     SmallVectorImpl<std::pair<unsigned, MDNode *>> &Result) const {
1302   Result.clear();
1303   assert(hasMetadataHashEntry() &&
1304          getContext().pImpl->InstructionMetadata.count(this) &&
1305          "Shouldn't have called this");
1306   const auto &Info = getContext().pImpl->InstructionMetadata.find(this)->second;
1307   assert(!Info.empty() && "Shouldn't have called this");
1308   Info.getAll(Result);
1309 }
1310
1311 bool Instruction::extractProfMetadata(uint64_t &TrueVal,
1312                                       uint64_t &FalseVal) const {
1313   assert(
1314       (getOpcode() == Instruction::Br || getOpcode() == Instruction::Select) &&
1315       "Looking for branch weights on something besides branch or select");
1316
1317   auto *ProfileData = getMetadata(LLVMContext::MD_prof);
1318   if (!ProfileData || ProfileData->getNumOperands() != 3)
1319     return false;
1320
1321   auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
1322   if (!ProfDataName || !ProfDataName->getString().equals("branch_weights"))
1323     return false;
1324
1325   auto *CITrue = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1));
1326   auto *CIFalse = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2));
1327   if (!CITrue || !CIFalse)
1328     return false;
1329
1330   TrueVal = CITrue->getValue().getZExtValue();
1331   FalseVal = CIFalse->getValue().getZExtValue();
1332
1333   return true;
1334 }
1335
1336 bool Instruction::extractProfTotalWeight(uint64_t &TotalVal) const {
1337   assert((getOpcode() == Instruction::Br ||
1338           getOpcode() == Instruction::Select ||
1339           getOpcode() == Instruction::Call ||
1340           getOpcode() == Instruction::Invoke ||
1341           getOpcode() == Instruction::Switch) &&
1342          "Looking for branch weights on something besides branch");
1343
1344   TotalVal = 0;
1345   auto *ProfileData = getMetadata(LLVMContext::MD_prof);
1346   if (!ProfileData)
1347     return false;
1348
1349   auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
1350   if (!ProfDataName)
1351     return false;
1352
1353   if (ProfDataName->getString().equals("branch_weights")) {
1354     TotalVal = 0;
1355     for (unsigned i = 1; i < ProfileData->getNumOperands(); i++) {
1356       auto *V = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i));
1357       if (!V)
1358         return false;
1359       TotalVal += V->getValue().getZExtValue();
1360     }
1361     return true;
1362   } else if (ProfDataName->getString().equals("VP") &&
1363              ProfileData->getNumOperands() > 3) {
1364     TotalVal = mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2))
1365                    ->getValue()
1366                    .getZExtValue();
1367     return true;
1368   }
1369   return false;
1370 }
1371
1372 void Instruction::clearMetadataHashEntries() {
1373   assert(hasMetadataHashEntry() && "Caller should check");
1374   getContext().pImpl->InstructionMetadata.erase(this);
1375   setHasMetadataHashEntry(false);
1376 }
1377
1378 void GlobalObject::getMetadata(unsigned KindID,
1379                                SmallVectorImpl<MDNode *> &MDs) const {
1380   if (hasMetadata())
1381     getContext().pImpl->GlobalObjectMetadata[this].get(KindID, MDs);
1382 }
1383
1384 void GlobalObject::getMetadata(StringRef Kind,
1385                                SmallVectorImpl<MDNode *> &MDs) const {
1386   if (hasMetadata())
1387     getMetadata(getContext().getMDKindID(Kind), MDs);
1388 }
1389
1390 void GlobalObject::addMetadata(unsigned KindID, MDNode &MD) {
1391   if (!hasMetadata())
1392     setHasMetadataHashEntry(true);
1393
1394   getContext().pImpl->GlobalObjectMetadata[this].insert(KindID, MD);
1395 }
1396
1397 void GlobalObject::addMetadata(StringRef Kind, MDNode &MD) {
1398   addMetadata(getContext().getMDKindID(Kind), MD);
1399 }
1400
1401 bool GlobalObject::eraseMetadata(unsigned KindID) {
1402   // Nothing to unset.
1403   if (!hasMetadata())
1404     return false;
1405
1406   auto &Store = getContext().pImpl->GlobalObjectMetadata[this];
1407   bool Changed = Store.erase(KindID);
1408   if (Store.empty())
1409     clearMetadata();
1410   return Changed;
1411 }
1412
1413 void GlobalObject::getAllMetadata(
1414     SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const {
1415   MDs.clear();
1416
1417   if (!hasMetadata())
1418     return;
1419
1420   getContext().pImpl->GlobalObjectMetadata[this].getAll(MDs);
1421 }
1422
1423 void GlobalObject::clearMetadata() {
1424   if (!hasMetadata())
1425     return;
1426   getContext().pImpl->GlobalObjectMetadata.erase(this);
1427   setHasMetadataHashEntry(false);
1428 }
1429
1430 void GlobalObject::setMetadata(unsigned KindID, MDNode *N) {
1431   eraseMetadata(KindID);
1432   if (N)
1433     addMetadata(KindID, *N);
1434 }
1435
1436 void GlobalObject::setMetadata(StringRef Kind, MDNode *N) {
1437   setMetadata(getContext().getMDKindID(Kind), N);
1438 }
1439
1440 MDNode *GlobalObject::getMetadata(unsigned KindID) const {
1441   if (hasMetadata())
1442     return getContext().pImpl->GlobalObjectMetadata[this].lookup(KindID);
1443   return nullptr;
1444 }
1445
1446 MDNode *GlobalObject::getMetadata(StringRef Kind) const {
1447   return getMetadata(getContext().getMDKindID(Kind));
1448 }
1449
1450 void GlobalObject::copyMetadata(const GlobalObject *Other, unsigned Offset) {
1451   SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
1452   Other->getAllMetadata(MDs);
1453   for (auto &MD : MDs) {
1454     // We need to adjust the type metadata offset.
1455     if (Offset != 0 && MD.first == LLVMContext::MD_type) {
1456       auto *OffsetConst = cast<ConstantInt>(
1457           cast<ConstantAsMetadata>(MD.second->getOperand(0))->getValue());
1458       Metadata *TypeId = MD.second->getOperand(1);
1459       auto *NewOffsetMD = ConstantAsMetadata::get(ConstantInt::get(
1460           OffsetConst->getType(), OffsetConst->getValue() + Offset));
1461       addMetadata(LLVMContext::MD_type,
1462                   *MDNode::get(getContext(), {NewOffsetMD, TypeId}));
1463       continue;
1464     }
1465     // If an offset adjustment was specified we need to modify the DIExpression
1466     // to prepend the adjustment:
1467     // !DIExpression(DW_OP_plus, Offset, [original expr])
1468     auto *Attachment = MD.second;
1469     if (Offset != 0 && MD.first == LLVMContext::MD_dbg) {
1470       DIGlobalVariable *GV = dyn_cast<DIGlobalVariable>(Attachment);
1471       DIExpression *E = nullptr;
1472       if (!GV) {
1473         auto *GVE = cast<DIGlobalVariableExpression>(Attachment);
1474         GV = GVE->getVariable();
1475         E = GVE->getExpression();
1476       }
1477       ArrayRef<uint64_t> OrigElements;
1478       if (E)
1479         OrigElements = E->getElements();
1480       std::vector<uint64_t> Elements(OrigElements.size() + 2);
1481       Elements[0] = dwarf::DW_OP_plus_uconst;
1482       Elements[1] = Offset;
1483       llvm::copy(OrigElements, Elements.begin() + 2);
1484       E = DIExpression::get(getContext(), Elements);
1485       Attachment = DIGlobalVariableExpression::get(getContext(), GV, E);
1486     }
1487     addMetadata(MD.first, *Attachment);
1488   }
1489 }
1490
1491 void GlobalObject::addTypeMetadata(unsigned Offset, Metadata *TypeID) {
1492   addMetadata(
1493       LLVMContext::MD_type,
1494       *MDTuple::get(getContext(),
1495                     {ConstantAsMetadata::get(ConstantInt::get(
1496                          Type::getInt64Ty(getContext()), Offset)),
1497                      TypeID}));
1498 }
1499
1500 void Function::setSubprogram(DISubprogram *SP) {
1501   setMetadata(LLVMContext::MD_dbg, SP);
1502 }
1503
1504 DISubprogram *Function::getSubprogram() const {
1505   return cast_or_null<DISubprogram>(getMetadata(LLVMContext::MD_dbg));
1506 }
1507
1508 bool Function::isDebugInfoForProfiling() const {
1509   if (DISubprogram *SP = getSubprogram()) {
1510     if (DICompileUnit *CU = SP->getUnit()) {
1511       return CU->getDebugInfoForProfiling();
1512     }
1513   }
1514   return false;
1515 }
1516
1517 void GlobalVariable::addDebugInfo(DIGlobalVariableExpression *GV) {
1518   addMetadata(LLVMContext::MD_dbg, *GV);
1519 }
1520
1521 void GlobalVariable::getDebugInfo(
1522     SmallVectorImpl<DIGlobalVariableExpression *> &GVs) const {
1523   SmallVector<MDNode *, 1> MDs;
1524   getMetadata(LLVMContext::MD_dbg, MDs);
1525   for (MDNode *MD : MDs)
1526     GVs.push_back(cast<DIGlobalVariableExpression>(MD));
1527 }