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, ArrayRef<Value*> Vals, bool isFunctionLocal)
  88 : Value(Type::getMetadataTy(C), Value::MDNodeVal) {
  89   NumOperands = Vals.size();
  90
  91   if (isFunctionLocal)
  92     setValueSubclassData(getSubclassDataFromValue() | FunctionLocalBit);
  93
  94   // Initialize the operand list, which is co-allocated on the end of the node.
  95   unsigned i = 0;
  96   for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
  97        Op != E; ++Op, ++i)
  98     new (Op) MDNodeOperand(Vals[i], 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, ArrayRef<Value*> Vals,
 187                           FunctionLocalness FL, bool Insert) {
 188   LLVMContextImpl *pImpl = Context.pImpl;
 189
 190   // Add all the operand pointers. Note that we don't have to add the
 191   // isFunctionLocal bit because that's implied by the operands.
 192   // Note that if the operands are later nulled out, the node will be
 193   // removed from the uniquing map.
 194   FoldingSetNodeID ID;
 195   for (unsigned i = 0; i != Vals.size(); ++i)
 196     ID.AddPointer(Vals[i]);
 197
 198   void *InsertPoint;
 199   MDNode *N = NULL;
 200
 201   if ((N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint)))
 202     return N;
 203
 204   bool isFunctionLocal = false;
 205   switch (FL) {
 206   case FL_Unknown:
 207     for (unsigned i = 0; i != Vals.size(); ++i) {
 208       Value *V = Vals[i];
 209       if (!V) continue;
 210       if (isFunctionLocalValue(V)) {
 211         isFunctionLocal = true;
 212         break;
 213       }
 214     }
 215     break;
 216   case FL_No:
 217     isFunctionLocal = false;
 218     break;
 219   case FL_Yes:
 220     isFunctionLocal = true;
 221     break;
 222   }
 223
 224   // Coallocate space for the node and Operands together, then placement new.
 225   void *Ptr = malloc(sizeof(MDNode)+Vals.size()*sizeof(MDNodeOperand));
 226   N = new (Ptr) MDNode(Context, Vals, isFunctionLocal);
 227
 228   // InsertPoint will have been set by the FindNodeOrInsertPos call.
 229   pImpl->MDNodeSet.InsertNode(N, InsertPoint);
 230
 231   return N;
 232 }
 233
 234 MDNode *MDNode::get(LLVMContext &Context, ArrayRef<Value*> Vals) {
 235   return getMDNode(Context, Vals, FL_Unknown);
 236 }
 237
 238 MDNode *MDNode::getWhenValsUnresolved(LLVMContext &Context,
 239                                       ArrayRef<Value*> Vals,
 240                                       bool isFunctionLocal) {
 241   return getMDNode(Context, Vals, isFunctionLocal ? FL_Yes : FL_No);
 242 }
 243
 244 MDNode *MDNode::getIfExists(LLVMContext &Context, ArrayRef<Value*> Vals) {
 245   return getMDNode(Context, Vals, FL_Unknown, false);
 246 }
 247
 248 MDNode *MDNode::getTemporary(LLVMContext &Context, ArrayRef<Value*> Vals) {
 249   MDNode *N =
 250     (MDNode *)malloc(sizeof(MDNode)+Vals.size()*sizeof(MDNodeOperand));
 251   N = new (N) MDNode(Context, Vals, FL_No);
 252   N->setValueSubclassData(N->getSubclassDataFromValue() |
 253                           NotUniquedBit);
 254   LeakDetector::addGarbageObject(N);
 255   return N;
 256 }
 257
 258 void MDNode::deleteTemporary(MDNode *N) {
 259   assert(N->use_empty() && "Temporary MDNode has uses!");
 260   assert(!N->getContext().pImpl->MDNodeSet.RemoveNode(N) &&
 261          "Deleting a non-temporary uniqued node!");
 262   assert(!N->getContext().pImpl->NonUniquedMDNodes.erase(N) &&
 263          "Deleting a non-temporary non-uniqued node!");
 264   assert((N->getSubclassDataFromValue() & NotUniquedBit) &&
 265          "Temporary MDNode does not have NotUniquedBit set!");
 266   assert((N->getSubclassDataFromValue() & DestroyFlag) == 0 &&
 267          "Temporary MDNode has DestroyFlag set!");
 268   LeakDetector::removeGarbageObject(N);
 269   N->destroy();
 270 }
 271
 272 /// getOperand - Return specified operand.
 273 Value *MDNode::getOperand(unsigned i) const {
 274   return *getOperandPtr(const_cast<MDNode*>(this), i);
 275 }
 276
 277 void MDNode::Profile(FoldingSetNodeID &ID) const {
 278   // Add all the operand pointers. Note that we don't have to add the
 279   // isFunctionLocal bit because that's implied by the operands.
 280   // Note that if the operands are later nulled out, the node will be
 281   // removed from the uniquing map.
 282   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
 283     ID.AddPointer(getOperand(i));
 284 }
 285
 286 void MDNode::setIsNotUniqued() {
 287   setValueSubclassData(getSubclassDataFromValue() | NotUniquedBit);
 288   LLVMContextImpl *pImpl = getType()->getContext().pImpl;
 289   pImpl->NonUniquedMDNodes.insert(this);
 290 }
 291
 292 // Replace value from this node's operand list.
 293 void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
 294   Value *From = *Op;
 295
 296   // If is possible that someone did GV->RAUW(inst), replacing a global variable
 297   // with an instruction or some other function-local object.  If this is a
 298   // non-function-local MDNode, it can't point to a function-local object.
 299   // Handle this case by implicitly dropping the MDNode reference to null.
 300   // Likewise if the MDNode is function-local but for a different function.
 301   if (To && isFunctionLocalValue(To)) {
 302     if (!isFunctionLocal())
 303       To = 0;
 304     else {
 305       const Function *F = getFunction();
 306       const Function *FV = getFunctionForValue(To);
 307       // Metadata can be function-local without having an associated function.
 308       // So only consider functions to have changed if non-null.
 309       if (F && FV && F != FV)
 310         To = 0;
 311     }
 312   }
 313
 314   if (From == To)
 315     return;
 316
 317   // Update the operand.
 318   Op->set(To);
 319
 320   // If this node is already not being uniqued (because one of the operands
 321   // already went to null), then there is nothing else to do here.
 322   if (isNotUniqued()) return;
 323
 324   LLVMContextImpl *pImpl = getType()->getContext().pImpl;
 325
 326   // Remove "this" from the context map.  FoldingSet doesn't have to reprofile
 327   // this node to remove it, so we don't care what state the operands are in.
 328   pImpl->MDNodeSet.RemoveNode(this);
 329
 330   // If we are dropping an argument to null, we choose to not unique the MDNode
 331   // anymore.  This commonly occurs during destruction, and uniquing these
 332   // brings little reuse.  Also, this means we don't need to include
 333   // isFunctionLocal bits in FoldingSetNodeIDs for MDNodes.
 334   if (To == 0) {
 335     setIsNotUniqued();
 336     return;
 337   }
 338
 339   // Now that the node is out of the folding set, get ready to reinsert it.
 340   // First, check to see if another node with the same operands already exists
 341   // in the set.  If so, then this node is redundant.
 342   FoldingSetNodeID ID;
 343   Profile(ID);
 344   void *InsertPoint;
 345   if (MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint)) {
 346     replaceAllUsesWith(N);
 347     destroy();
 348     return;
 349   }
 350
 351   // InsertPoint will have been set by the FindNodeOrInsertPos call.
 352   pImpl->MDNodeSet.InsertNode(this, InsertPoint);
 353
 354   // If this MDValue was previously function-local but no longer is, clear
 355   // its function-local flag.
 356   if (isFunctionLocal() && !isFunctionLocalValue(To)) {
 357     bool isStillFunctionLocal = false;
 358     for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
 359       Value *V = getOperand(i);
 360       if (!V) continue;
 361       if (isFunctionLocalValue(V)) {
 362         isStillFunctionLocal = true;
 363         break;
 364       }
 365     }
 366     if (!isStillFunctionLocal)
 367       setValueSubclassData(getSubclassDataFromValue() & ~FunctionLocalBit);
 368   }
 369 }
 370
 371 //===----------------------------------------------------------------------===//
 372 // NamedMDNode implementation.
 373 //
 374
 375 static SmallVector<TrackingVH<MDNode>, 4> &getNMDOps(void *Operands) {
 376   return *(SmallVector<TrackingVH<MDNode>, 4>*)Operands;
 377 }
 378
 379 NamedMDNode::NamedMDNode(const Twine &N)
 380   : Name(N.str()), Parent(0),
 381     Operands(new SmallVector<TrackingVH<MDNode>, 4>()) {
 382 }
 383
 384 NamedMDNode::~NamedMDNode() {
 385   dropAllReferences();
 386   delete &getNMDOps(Operands);
 387 }
 388
 389 /// getNumOperands - Return number of NamedMDNode operands.
 390 unsigned NamedMDNode::getNumOperands() const {
 391   return (unsigned)getNMDOps(Operands).size();
 392 }
 393
 394 /// getOperand - Return specified operand.
 395 MDNode *NamedMDNode::getOperand(unsigned i) const {
 396   assert(i < getNumOperands() && "Invalid Operand number!");
 397   return dyn_cast<MDNode>(&*getNMDOps(Operands)[i]);
 398 }
 399
 400 /// addOperand - Add metadata Operand.
 401 void NamedMDNode::addOperand(MDNode *M) {
 402   assert(!M->isFunctionLocal() &&
 403          "NamedMDNode operands must not be function-local!");
 404   getNMDOps(Operands).push_back(TrackingVH<MDNode>(M));
 405 }
 406
 407 /// eraseFromParent - Drop all references and remove the node from parent
 408 /// module.
 409 void NamedMDNode::eraseFromParent() {
 410   getParent()->eraseNamedMetadata(this);
 411 }
 412
 413 /// dropAllReferences - Remove all uses and clear node vector.
 414 void NamedMDNode::dropAllReferences() {
 415   getNMDOps(Operands).clear();
 416 }
 417
 418 /// getName - Return a constant reference to this named metadata's name.
 419 StringRef NamedMDNode::getName() const {
 420   return StringRef(Name);
 421 }
 422
 423 //===----------------------------------------------------------------------===//
 424 // Instruction Metadata method implementations.
 425 //
 426
 427 void Instruction::setMetadata(const char *Kind, MDNode *Node) {
 428   if (Node == 0 && !hasMetadata()) return;
 429   setMetadata(getContext().getMDKindID(Kind), Node);
 430 }
 431
 432 MDNode *Instruction::getMetadataImpl(const char *Kind) const {
 433   return getMetadataImpl(getContext().getMDKindID(Kind));
 434 }
 435
 436 /// setMetadata - Set the metadata of of the specified kind to the specified
 437 /// node.  This updates/replaces metadata if already present, or removes it if
 438 /// Node is null.
 439 void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
 440   if (Node == 0 && !hasMetadata()) return;
 441
 442   // Handle 'dbg' as a special case since it is not stored in the hash table.
 443   if (KindID == LLVMContext::MD_dbg) {
 444     DbgLoc = DebugLoc::getFromDILocation(Node);
 445     return;
 446   }
 447
 448   // Handle the case when we're adding/updating metadata on an instruction.
 449   if (Node) {
 450     LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
 451     assert(!Info.empty() == hasMetadataHashEntry() &&
 452            "HasMetadata bit is wonked");
 453     if (Info.empty()) {
 454       setHasMetadataHashEntry(true);
 455     } else {
 456       // Handle replacement of an existing value.
 457       for (unsigned i = 0, e = Info.size(); i != e; ++i)
 458         if (Info[i].first == KindID) {
 459           Info[i].second = Node;
 460           return;
 461         }
 462     }
 463
 464     // No replacement, just add it to the list.
 465     Info.push_back(std::make_pair(KindID, Node));
 466     return;
 467   }
 468
 469   // Otherwise, we're removing metadata from an instruction.
 470   assert(hasMetadataHashEntry() &&
 471          getContext().pImpl->MetadataStore.count(this) &&
 472          "HasMetadata bit out of date!");
 473   LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
 474
 475   // Common case is removing the only entry.
 476   if (Info.size() == 1 && Info[0].first == KindID) {
 477     getContext().pImpl->MetadataStore.erase(this);
 478     setHasMetadataHashEntry(false);
 479     return;
 480   }
 481
 482   // Handle removal of an existing value.
 483   for (unsigned i = 0, e = Info.size(); i != e; ++i)
 484     if (Info[i].first == KindID) {
 485       Info[i] = Info.back();
 486       Info.pop_back();
 487       assert(!Info.empty() && "Removing last entry should be handled above");
 488       return;
 489     }
 490   // Otherwise, removing an entry that doesn't exist on the instruction.
 491 }
 492
 493 MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
 494   // Handle 'dbg' as a special case since it is not stored in the hash table.
 495   if (KindID == LLVMContext::MD_dbg)
 496     return DbgLoc.getAsMDNode(getContext());
 497
 498   if (!hasMetadataHashEntry()) return 0;
 499
 500   LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
 501   assert(!Info.empty() && "bit out of sync with hash table");
 502
 503   for (LLVMContextImpl::MDMapTy::iterator I = Info.begin(), E = Info.end();
 504        I != E; ++I)
 505     if (I->first == KindID)
 506       return I->second;
 507   return 0;
 508 }
 509
 510 void Instruction::getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,
 511                                        MDNode*> > &Result) const {
 512   Result.clear();
 513
 514   // Handle 'dbg' as a special case since it is not stored in the hash table.
 515   if (!DbgLoc.isUnknown()) {
 516     Result.push_back(std::make_pair((unsigned)LLVMContext::MD_dbg,
 517                                     DbgLoc.getAsMDNode(getContext())));
 518     if (!hasMetadataHashEntry()) return;
 519   }
 520
 521   assert(hasMetadataHashEntry() &&
 522          getContext().pImpl->MetadataStore.count(this) &&
 523          "Shouldn't have called this");
 524   const LLVMContextImpl::MDMapTy &Info =
 525     getContext().pImpl->MetadataStore.find(this)->second;
 526   assert(!Info.empty() && "Shouldn't have called this");
 527
 528   Result.append(Info.begin(), Info.end());
 529
 530   // Sort the resulting array so it is stable.
 531   if (Result.size() > 1)
 532     array_pod_sort(Result.begin(), Result.end());
 533 }
 534
 535 void Instruction::
 536 getAllMetadataOtherThanDebugLocImpl(SmallVectorImpl<std::pair<unsigned,
 537                                     MDNode*> > &Result) const {
 538   Result.clear();
 539   assert(hasMetadataHashEntry() &&
 540          getContext().pImpl->MetadataStore.count(this) &&
 541          "Shouldn't have called this");
 542   const LLVMContextImpl::MDMapTy &Info =
 543   getContext().pImpl->MetadataStore.find(this)->second;
 544   assert(!Info.empty() && "Shouldn't have called this");
 545
 546   Result.append(Info.begin(), Info.end());
 547
 548   // Sort the resulting array so it is stable.
 549   if (Result.size() > 1)
 550     array_pod_sort(Result.begin(), Result.end());
 551 }
 552
 553
 554 /// clearMetadataHashEntries - Clear all hashtable-based metadata from
 555 /// this instruction.
 556 void Instruction::clearMetadataHashEntries() {
 557   assert(hasMetadataHashEntry() && "Caller should check");
 558   getContext().pImpl->MetadataStore.erase(this);
 559   setHasMetadataHashEntry(false);
 560 }
 561