lib/VMCore/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 "llvm/Metadata.h"
  15 #include "LLVMContextImpl.h"
  16 #include "llvm/LLVMContext.h"
  17 #include "llvm/Module.h"
  18 #include "llvm/Instruction.h"
  19 #include "llvm/ADT/DenseMap.h"
  20 #include "llvm/ADT/StringMap.h"
  21 #include "llvm/ADT/SmallString.h"
  22 #include "SymbolTableListTraitsImpl.h"
  23 #include "llvm/Support/LeakDetector.h"
  24 #include "llvm/Support/ValueHandle.h"
  25 using namespace llvm;
  26
  27 //===----------------------------------------------------------------------===//
  28 // MDString implementation.
  29 //
  30
  31 MDString::MDString(LLVMContext &C, StringRef S)
  32   : Value(Type::getMetadataTy(C), Value::MDStringVal), Str(S) {}
  33
  34 MDString *MDString::get(LLVMContext &Context, StringRef Str) {
  35   LLVMContextImpl *pImpl = Context.pImpl;
  36   StringMapEntry<MDString *> &Entry =
  37     pImpl->MDStringCache.GetOrCreateValue(Str);
  38   MDString *&S = Entry.getValue();
  39   if (!S) S = new MDString(Context, Entry.getKey());
  40   return S;
  41 }
  42
  43 //===----------------------------------------------------------------------===//
  44 // MDNodeOperand implementation.
  45 //
  46
  47 // Use CallbackVH to hold MDNode operands.
  48 namespace llvm {
  49 class MDNodeOperand : public CallbackVH {
  50   MDNode *Parent;
  51 public:
  52   MDNodeOperand(Value *V, MDNode *P) : CallbackVH(V), Parent(P) {}
  53   ~MDNodeOperand() {}
  54
  55   void set(Value *V) {
  56     setValPtr(V);
  57   }
  58
  59   virtual void deleted();
  60   virtual void allUsesReplacedWith(Value *NV);
  61 };
  62 } // end namespace llvm.
  63
  64
  65 void MDNodeOperand::deleted() {
  66   Parent->replaceOperand(this, 0);
  67 }
  68
  69 void MDNodeOperand::allUsesReplacedWith(Value *NV) {
  70   Parent->replaceOperand(this, NV);
  71 }
  72
  73
  74
  75 //===----------------------------------------------------------------------===//
  76 // MDNode implementation.
  77 //
  78
  79 /// getOperandPtr - Helper function to get the MDNodeOperand's coallocated on
  80 /// the end of the MDNode.
  81 static MDNodeOperand *getOperandPtr(MDNode *N, unsigned Op) {
  82   // Use <= instead of < to permit a one-past-the-end address.
  83   assert(Op <= N->getNumOperands() && "Invalid operand number");
  84   return reinterpret_cast<MDNodeOperand*>(N+1)+Op;
  85 }
  86
  87 MDNode::MDNode(LLVMContext &C, Value *const *Vals, unsigned NumVals,
  88                bool isFunctionLocal)
  89 : Value(Type::getMetadataTy(C), Value::MDNodeVal) {
  90   NumOperands = NumVals;
  91
  92   if (isFunctionLocal)
  93     setValueSubclassData(getSubclassDataFromValue() | FunctionLocalBit);
  94
  95   // Initialize the operand list, which is co-allocated on the end of the node.
  96   for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
  97        Op != E; ++Op, ++Vals)
  98     new (Op) MDNodeOperand(*Vals, this);
  99 }
 100
 101
 102 /// ~MDNode - Destroy MDNode.
 103 MDNode::~MDNode() {
 104   assert((getSubclassDataFromValue() & DestroyFlag) != 0 &&
 105          "Not being destroyed through destroy()?");
 106   LLVMContextImpl *pImpl = getType()->getContext().pImpl;
 107   if (isNotUniqued()) {
 108     pImpl->NonUniquedMDNodes.erase(this);
 109   } else {
 110     pImpl->MDNodeSet.RemoveNode(this);
 111   }
 112
 113   // Destroy the operands.
 114   for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
 115        Op != E; ++Op)
 116     Op->~MDNodeOperand();
 117 }
 118
 119 static const Function *getFunctionForValue(Value *V) {
 120   if (!V) return NULL;
 121   if (Instruction *I = dyn_cast<Instruction>(V)) {
 122     BasicBlock *BB = I->getParent();
 123     return BB ? BB->getParent() : 0;
 124   }
 125   if (Argument *A = dyn_cast<Argument>(V))
 126     return A->getParent();
 127   if (BasicBlock *BB = dyn_cast<BasicBlock>(V))
 128     return BB->getParent();
 129   if (MDNode *MD = dyn_cast<MDNode>(V))
 130     return MD->getFunction();
 131   return NULL;
 132 }
 133
 134 #ifndef NDEBUG
 135 static const Function *assertLocalFunction(const MDNode *N) {
 136   if (!N->isFunctionLocal()) return 0;
 137
 138   // FIXME: This does not handle cyclic function local metadata.
 139   const Function *F = 0, *NewF = 0;
 140   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 141     if (Value *V = N->getOperand(i)) {
 142       if (MDNode *MD = dyn_cast<MDNode>(V))
 143         NewF = assertLocalFunction(MD);
 144       else
 145         NewF = getFunctionForValue(V);
 146     }
 147     if (F == 0)
 148       F = NewF;
 149     else
 150       assert((NewF == 0 || F == NewF) &&"inconsistent function-local metadata");
 151   }
 152   return F;
 153 }
 154 #endif
 155
 156 // getFunction - If this metadata is function-local and recursively has a
 157 // function-local operand, return the first such operand's parent function.
 158 // Otherwise, return null. getFunction() should not be used for performance-
 159 // critical code because it recursively visits all the MDNode's operands.
 160 const Function *MDNode::getFunction() const {
 161 #ifndef NDEBUG
 162   return assertLocalFunction(this);
 163 #endif
 164   if (!isFunctionLocal()) return NULL;
 165   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
 166     if (const Function *F = getFunctionForValue(getOperand(i)))
 167       return F;
 168   return NULL;
 169 }
 170
 171 // destroy - Delete this node.  Only when there are no uses.
 172 void MDNode::destroy() {
 173   setValueSubclassData(getSubclassDataFromValue() | DestroyFlag);
 174   // Placement delete, the free the memory.
 175   this->~MDNode();
 176   free(this);
 177 }
 178
 179 /// isFunctionLocalValue - Return true if this is a value that would require a
 180 /// function-local MDNode.
 181 static bool isFunctionLocalValue(Value *V) {
 182   return isa<Instruction>(V) || isa<Argument>(V) || isa<BasicBlock>(V) ||
 183          (isa<MDNode>(V) && cast<MDNode>(V)->isFunctionLocal());
 184 }
 185
 186 MDNode *MDNode::getMDNode(LLVMContext &Context, Value *const *Vals,
 187                           unsigned NumVals, FunctionLocalness FL,
 188                           bool Insert) {
 189   LLVMContextImpl *pImpl = Context.pImpl;
 190
 191   // Add all the operand pointers. Note that we don't have to add the
 192   // isFunctionLocal bit because that's implied by the operands.
 193   // Note that if the operands are later nulled out, the node will be
 194   // removed from the uniquing map.
 195   FoldingSetNodeID ID;
 196   for (unsigned i = 0; i != NumVals; ++i)
 197     ID.AddPointer(Vals[i]);
 198
 199   void *InsertPoint;
 200   MDNode *N = NULL;
 201
 202   if ((N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint)))
 203     return N;
 204
 205   bool isFunctionLocal = false;
 206   switch (FL) {
 207   case FL_Unknown:
 208     for (unsigned i = 0; i != NumVals; ++i) {
 209       Value *V = Vals[i];
 210       if (!V) continue;
 211       if (isFunctionLocalValue(V)) {
 212         isFunctionLocal = true;
 213         break;
 214       }
 215     }
 216     break;
 217   case FL_No:
 218     isFunctionLocal = false;
 219     break;
 220   case FL_Yes:
 221     isFunctionLocal = true;
 222     break;
 223   }
 224
 225   // Coallocate space for the node and Operands together, then placement new.
 226   void *Ptr = malloc(sizeof(MDNode)+NumVals*sizeof(MDNodeOperand));
 227   N = new (Ptr) MDNode(Context, Vals, NumVals, isFunctionLocal);
 228
 229   // InsertPoint will have been set by the FindNodeOrInsertPos call.
 230   pImpl->MDNodeSet.InsertNode(N, InsertPoint);
 231
 232   return N;
 233 }
 234
 235 MDNode *MDNode::get(LLVMContext &Context, ArrayRef<Value*> Vals) {
 236   return getMDNode(Context, Vals.data(), Vals.size(), FL_Unknown);
 237 }
 238 MDNode *MDNode::get(LLVMContext &Context, Value*const* Vals, unsigned NumVals) {
 239   return getMDNode(Context, Vals, NumVals, FL_Unknown);
 240 }
 241
 242 MDNode *MDNode::getWhenValsUnresolved(LLVMContext &Context, Value *const *Vals,
 243                                       unsigned NumVals, bool isFunctionLocal) {
 244   return getMDNode(Context, Vals, NumVals, isFunctionLocal ? FL_Yes : FL_No);
 245 }
 246
 247 MDNode *MDNode::getIfExists(LLVMContext &Context, Value *const *Vals,
 248                             unsigned NumVals) {
 249   return getMDNode(Context, Vals, NumVals, FL_Unknown, false);
 250 }
 251
 252 MDNode *MDNode::getTemporary(LLVMContext &Context, Value *const *Vals,
 253                              unsigned NumVals) {
 254   MDNode *N = (MDNode *)malloc(sizeof(MDNode)+NumVals*sizeof(MDNodeOperand));
 255   N = new (N) MDNode(Context, Vals, NumVals, FL_No);
 256   N->setValueSubclassData(N->getSubclassDataFromValue() |
 257                           NotUniquedBit);
 258   LeakDetector::addGarbageObject(N);
 259   return N;
 260 }
 261
 262 void MDNode::deleteTemporary(MDNode *N) {
 263   assert(N->use_empty() && "Temporary MDNode has uses!");
 264   assert(!N->getContext().pImpl->MDNodeSet.RemoveNode(N) &&
 265          "Deleting a non-temporary uniqued node!");
 266   assert(!N->getContext().pImpl->NonUniquedMDNodes.erase(N) &&
 267          "Deleting a non-temporary non-uniqued node!");
 268   assert((N->getSubclassDataFromValue() & NotUniquedBit) &&
 269          "Temporary MDNode does not have NotUniquedBit set!");
 270   assert((N->getSubclassDataFromValue() & DestroyFlag) == 0 &&
 271          "Temporary MDNode has DestroyFlag set!");
 272   LeakDetector::removeGarbageObject(N);
 273   N->destroy();
 274 }
 275
 276 /// getOperand - Return specified operand.
 277 Value *MDNode::getOperand(unsigned i) const {
 278   return *getOperandPtr(const_cast<MDNode*>(this), i);
 279 }
 280
 281 void MDNode::Profile(FoldingSetNodeID &ID) const {
 282   // Add all the operand pointers. Note that we don't have to add the
 283   // isFunctionLocal bit because that's implied by the operands.
 284   // Note that if the operands are later nulled out, the node will be
 285   // removed from the uniquing map.
 286   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
 287     ID.AddPointer(getOperand(i));
 288 }
 289
 290 void MDNode::setIsNotUniqued() {
 291   setValueSubclassData(getSubclassDataFromValue() | NotUniquedBit);
 292   LLVMContextImpl *pImpl = getType()->getContext().pImpl;
 293   pImpl->NonUniquedMDNodes.insert(this);
 294 }
 295
 296 // Replace value from this node's operand list.
 297 void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
 298   Value *From = *Op;
 299
 300   // If is possible that someone did GV->RAUW(inst), replacing a global variable
 301   // with an instruction or some other function-local object.  If this is a
 302   // non-function-local MDNode, it can't point to a function-local object.
 303   // Handle this case by implicitly dropping the MDNode reference to null.
 304   // Likewise if the MDNode is function-local but for a different function.
 305   if (To && isFunctionLocalValue(To)) {
 306     if (!isFunctionLocal())
 307       To = 0;
 308     else {
 309       const Function *F = getFunction();
 310       const Function *FV = getFunctionForValue(To);
 311       // Metadata can be function-local without having an associated function.
 312       // So only consider functions to have changed if non-null.
 313       if (F && FV && F != FV)
 314         To = 0;
 315     }
 316   }
 317
 318   if (From == To)
 319     return;
 320
 321   // Update the operand.
 322   Op->set(To);
 323
 324   // If this node is already not being uniqued (because one of the operands
 325   // already went to null), then there is nothing else to do here.
 326   if (isNotUniqued()) return;
 327
 328   LLVMContextImpl *pImpl = getType()->getContext().pImpl;
 329
 330   // Remove "this" from the context map.  FoldingSet doesn't have to reprofile
 331   // this node to remove it, so we don't care what state the operands are in.
 332   pImpl->MDNodeSet.RemoveNode(this);
 333
 334   // If we are dropping an argument to null, we choose to not unique the MDNode
 335   // anymore.  This commonly occurs during destruction, and uniquing these
 336   // brings little reuse.  Also, this means we don't need to include
 337   // isFunctionLocal bits in FoldingSetNodeIDs for MDNodes.
 338   if (To == 0) {
 339     setIsNotUniqued();
 340     return;
 341   }
 342
 343   // Now that the node is out of the folding set, get ready to reinsert it.
 344   // First, check to see if another node with the same operands already exists
 345   // in the set.  If so, then this node is redundant.
 346   FoldingSetNodeID ID;
 347   Profile(ID);
 348   void *InsertPoint;
 349   if (MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint)) {
 350     replaceAllUsesWith(N);
 351     destroy();
 352     return;
 353   }
 354
 355   // InsertPoint will have been set by the FindNodeOrInsertPos call.
 356   pImpl->MDNodeSet.InsertNode(this, InsertPoint);
 357
 358   // If this MDValue was previously function-local but no longer is, clear
 359   // its function-local flag.
 360   if (isFunctionLocal() && !isFunctionLocalValue(To)) {
 361     bool isStillFunctionLocal = false;
 362     for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
 363       Value *V = getOperand(i);
 364       if (!V) continue;
 365       if (isFunctionLocalValue(V)) {
 366         isStillFunctionLocal = true;
 367         break;
 368       }
 369     }
 370     if (!isStillFunctionLocal)
 371       setValueSubclassData(getSubclassDataFromValue() & ~FunctionLocalBit);
 372   }
 373 }
 374
 375 //===----------------------------------------------------------------------===//
 376 // NamedMDNode implementation.
 377 //
 378
 379 static SmallVector<TrackingVH<MDNode>, 4> &getNMDOps(void *Operands) {
 380   return *(SmallVector<TrackingVH<MDNode>, 4>*)Operands;
 381 }
 382
 383 NamedMDNode::NamedMDNode(const Twine &N)
 384   : Name(N.str()), Parent(0),
 385     Operands(new SmallVector<TrackingVH<MDNode>, 4>()) {
 386 }
 387
 388 NamedMDNode::~NamedMDNode() {
 389   dropAllReferences();
 390   delete &getNMDOps(Operands);
 391 }
 392
 393 /// getNumOperands - Return number of NamedMDNode operands.
 394 unsigned NamedMDNode::getNumOperands() const {
 395   return (unsigned)getNMDOps(Operands).size();
 396 }
 397
 398 /// getOperand - Return specified operand.
 399 MDNode *NamedMDNode::getOperand(unsigned i) const {
 400   assert(i < getNumOperands() && "Invalid Operand number!");
 401   return dyn_cast<MDNode>(&*getNMDOps(Operands)[i]);
 402 }
 403
 404 /// addOperand - Add metadata Operand.
 405 void NamedMDNode::addOperand(MDNode *M) {
 406   assert(!M->isFunctionLocal() &&
 407          "NamedMDNode operands must not be function-local!");
 408   getNMDOps(Operands).push_back(TrackingVH<MDNode>(M));
 409 }
 410
 411 /// eraseFromParent - Drop all references and remove the node from parent
 412 /// module.
 413 void NamedMDNode::eraseFromParent() {
 414   getParent()->eraseNamedMetadata(this);
 415 }
 416
 417 /// dropAllReferences - Remove all uses and clear node vector.
 418 void NamedMDNode::dropAllReferences() {
 419   getNMDOps(Operands).clear();
 420 }
 421
 422 /// getName - Return a constant reference to this named metadata's name.
 423 StringRef NamedMDNode::getName() const {
 424   return StringRef(Name);
 425 }
 426
 427 //===----------------------------------------------------------------------===//
 428 // Instruction Metadata method implementations.
 429 //
 430
 431 void Instruction::setMetadata(const char *Kind, MDNode *Node) {
 432   if (Node == 0 && !hasMetadata()) return;
 433   setMetadata(getContext().getMDKindID(Kind), Node);
 434 }
 435
 436 MDNode *Instruction::getMetadataImpl(const char *Kind) const {
 437   return getMetadataImpl(getContext().getMDKindID(Kind));
 438 }
 439
 440 /// setMetadata - Set the metadata of of the specified kind to the specified
 441 /// node.  This updates/replaces metadata if already present, or removes it if
 442 /// Node is null.
 443 void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
 444   if (Node == 0 && !hasMetadata()) return;
 445
 446   // Handle 'dbg' as a special case since it is not stored in the hash table.
 447   if (KindID == LLVMContext::MD_dbg) {
 448     DbgLoc = DebugLoc::getFromDILocation(Node);
 449     return;
 450   }
 451
 452   // Handle the case when we're adding/updating metadata on an instruction.
 453   if (Node) {
 454     LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
 455     assert(!Info.empty() == hasMetadataHashEntry() &&
 456            "HasMetadata bit is wonked");
 457     if (Info.empty()) {
 458       setHasMetadataHashEntry(true);
 459     } else {
 460       // Handle replacement of an existing value.
 461       for (unsigned i = 0, e = Info.size(); i != e; ++i)
 462         if (Info[i].first == KindID) {
 463           Info[i].second = Node;
 464           return;
 465         }
 466     }
 467
 468     // No replacement, just add it to the list.
 469     Info.push_back(std::make_pair(KindID, Node));
 470     return;
 471   }
 472
 473   // Otherwise, we're removing metadata from an instruction.
 474   assert(hasMetadataHashEntry() &&
 475          getContext().pImpl->MetadataStore.count(this) &&
 476          "HasMetadata bit out of date!");
 477   LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
 478
 479   // Common case is removing the only entry.
 480   if (Info.size() == 1 && Info[0].first == KindID) {
 481     getContext().pImpl->MetadataStore.erase(this);
 482     setHasMetadataHashEntry(false);
 483     return;
 484   }
 485
 486   // Handle removal of an existing value.
 487   for (unsigned i = 0, e = Info.size(); i != e; ++i)
 488     if (Info[i].first == KindID) {
 489       Info[i] = Info.back();
 490       Info.pop_back();
 491       assert(!Info.empty() && "Removing last entry should be handled above");
 492       return;
 493     }
 494   // Otherwise, removing an entry that doesn't exist on the instruction.
 495 }
 496
 497 MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
 498   // Handle 'dbg' as a special case since it is not stored in the hash table.
 499   if (KindID == LLVMContext::MD_dbg)
 500     return DbgLoc.getAsMDNode(getContext());
 501
 502   if (!hasMetadataHashEntry()) return 0;
 503
 504   LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
 505   assert(!Info.empty() && "bit out of sync with hash table");
 506
 507   for (LLVMContextImpl::MDMapTy::iterator I = Info.begin(), E = Info.end();
 508        I != E; ++I)
 509     if (I->first == KindID)
 510       return I->second;
 511   return 0;
 512 }
 513
 514 void Instruction::getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,
 515                                        MDNode*> > &Result) const {
 516   Result.clear();
 517
 518   // Handle 'dbg' as a special case since it is not stored in the hash table.
 519   if (!DbgLoc.isUnknown()) {
 520     Result.push_back(std::make_pair((unsigned)LLVMContext::MD_dbg,
 521                                     DbgLoc.getAsMDNode(getContext())));
 522     if (!hasMetadataHashEntry()) return;
 523   }
 524
 525   assert(hasMetadataHashEntry() &&
 526          getContext().pImpl->MetadataStore.count(this) &&
 527          "Shouldn't have called this");
 528   const LLVMContextImpl::MDMapTy &Info =
 529     getContext().pImpl->MetadataStore.find(this)->second;
 530   assert(!Info.empty() && "Shouldn't have called this");
 531
 532   Result.append(Info.begin(), Info.end());
 533
 534   // Sort the resulting array so it is stable.
 535   if (Result.size() > 1)
 536     array_pod_sort(Result.begin(), Result.end());
 537 }
 538
 539 void Instruction::
 540 getAllMetadataOtherThanDebugLocImpl(SmallVectorImpl<std::pair<unsigned,
 541                                     MDNode*> > &Result) const {
 542   Result.clear();
 543   assert(hasMetadataHashEntry() &&
 544          getContext().pImpl->MetadataStore.count(this) &&
 545          "Shouldn't have called this");
 546   const LLVMContextImpl::MDMapTy &Info =
 547   getContext().pImpl->MetadataStore.find(this)->second;
 548   assert(!Info.empty() && "Shouldn't have called this");
 549
 550   Result.append(Info.begin(), Info.end());
 551
 552   // Sort the resulting array so it is stable.
 553   if (Result.size() > 1)
 554     array_pod_sort(Result.begin(), Result.end());
 555 }
 556
 557
 558 /// clearMetadataHashEntries - Clear all hashtable-based metadata from
 559 /// this instruction.
 560 void Instruction::clearMetadataHashEntries() {
 561   assert(hasMetadataHashEntry() && "Caller should check");
 562   getContext().pImpl->MetadataStore.erase(this);
 563   setHasMetadataHashEntry(false);
 564 }
 565