llvm/lib/VMCore/Metadata.cpp

//===-- Metadata.cpp - Implement Metadata classes -------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Metadata classes.
//
//===----------------------------------------------------------------------===//

#include "LLVMContextImpl.h"
#include "llvm/Metadata.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Instruction.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "SymbolTableListTraitsImpl.h"
using namespace llvm;

//===----------------------------------------------------------------------===//
// MetadataBase implementation.
//

//===----------------------------------------------------------------------===//
// MDString implementation.
//
MDString *MDString::get(LLVMContext &Context, StringRef Str) {
  LLVMContextImpl *pImpl = Context.pImpl;
  StringMapEntry<MDString *> &Entry = 
    pImpl->MDStringCache.GetOrCreateValue(Str);
  MDString *&S = Entry.getValue();
  if (!S) S = new MDString(Context, Entry.getKey());
  return S;
}

MDString *MDString::get(LLVMContext &Context, const char *Str) {
  LLVMContextImpl *pImpl = Context.pImpl;
  StringMapEntry<MDString *> &Entry = 
    pImpl->MDStringCache.GetOrCreateValue(Str ? StringRef(Str) : StringRef());
  MDString *&S = Entry.getValue();
  if (!S) S = new MDString(Context, Entry.getKey());
  return S;
}

//===----------------------------------------------------------------------===//
// MDNode implementation.
//
MDNode::MDNode(LLVMContext &C, Value *const *Vals, unsigned NumVals,
               bool isFunctionLocal)
  : MetadataBase(Type::getMetadataTy(C), Value::MDNodeVal) {
  NodeSize = NumVals;
  Node = new ElementVH[NodeSize];
  ElementVH *Ptr = Node;
  for (unsigned i = 0; i != NumVals; ++i) 
    *Ptr++ = ElementVH(Vals[i], this);
  if (isFunctionLocal)
    SubclassData |= FunctionLocalBit;
}

void MDNode::Profile(FoldingSetNodeID &ID) const {
  for (unsigned i = 0, e = getNumElements(); i != e; ++i)
    ID.AddPointer(getElement(i));
}

MDNode *MDNode::get(LLVMContext &Context, Value*const* Vals, unsigned NumVals,
                    bool isFunctionLocal) {
  LLVMContextImpl *pImpl = Context.pImpl;
  FoldingSetNodeID ID;
  for (unsigned i = 0; i != NumVals; ++i)
    ID.AddPointer(Vals[i]);

  void *InsertPoint;
  MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
  if (!N) {
    // InsertPoint will have been set by the FindNodeOrInsertPos call.
    N = new MDNode(Context, Vals, NumVals, isFunctionLocal);
    pImpl->MDNodeSet.InsertNode(N, InsertPoint);
  }
  return N;
}

/// ~MDNode - Destroy MDNode.
MDNode::~MDNode() {
  LLVMContextImpl *pImpl = getType()->getContext().pImpl;
  pImpl->MDNodeSet.RemoveNode(this);
  delete [] Node;
  Node = NULL;
}

// Replace value from this node's element list.
void MDNode::replaceElement(Value *From, Value *To) {
  if (From == To || !getType())
    return;
  LLVMContext &Context = getType()->getContext();
  LLVMContextImpl *pImpl = Context.pImpl;

  // Find value. This is a linear search, do something if it consumes 
  // lot of time. It is possible that to have multiple instances of
  // From in this MDNode's element list.
  SmallVector<unsigned, 4> Indexes;
  unsigned Index = 0;
  for (unsigned i = 0, e = getNumElements(); i != e; ++i, ++Index) {
    Value *V = getElement(i);
    if (V && V == From) 
      Indexes.push_back(Index);
  }

  if (Indexes.empty())
    return;

  // Remove "this" from the context map. 
  pImpl->MDNodeSet.RemoveNode(this);

  // Replace From element(s) in place.
  for (SmallVector<unsigned, 4>::iterator I = Indexes.begin(), E = Indexes.end(); 
       I != E; ++I) {
    unsigned Index = *I;
    Node[Index] = ElementVH(To, this);
  }

  // Insert updated "this" into the context's folding node set.
  // If a node with same element list already exist then before inserting 
  // updated "this" into the folding node set, replace all uses of existing 
  // node with updated "this" node.
  FoldingSetNodeID ID;
  Profile(ID);
  void *InsertPoint;
  MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);

  if (N) {
    N->replaceAllUsesWith(this);
    delete N;
    N = 0;
  }

  N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
  if (!N) {
    // InsertPoint will have been set by the FindNodeOrInsertPos call.
    N = this;
    pImpl->MDNodeSet.InsertNode(N, InsertPoint);
  }
}

// getLocalFunction - Return false if MDNode's recursive function-localness is
// invalid (local to more than one function).  Return true otherwise. If MDNode
// has one function to which it is local, set LocalFunction to that function.
bool MDNode::getLocalFunction(Function *LocalFunction,
                              SmallPtrSet<MDNode *, 32> *VisitedMDNodes) {
  if (!isFunctionLocal())
    return true;
    
  if (!VisitedMDNodes)
    VisitedMDNodes = new SmallPtrSet<MDNode *, 32>();
    
  if (!VisitedMDNodes->insert(this))
    // MDNode has already been visited, nothing to do.
    return true;

  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
    Value *V = getElement(i);
    if (!V) continue;

    Function *LocalFunctionTemp = NULL;
    if (Instruction *I = dyn_cast<Instruction>(V))
      LocalFunctionTemp = I->getParent()->getParent();
    else if (MDNode *MD = dyn_cast<MDNode>(V))
      if (!MD->getLocalFunction(LocalFunctionTemp, VisitedMDNodes))
        // This MDNode's operand is function-locally invalid or local to a
        // different function.
        return false;

    if (LocalFunctionTemp)
      if (!LocalFunction)
        LocalFunction = LocalFunctionTemp;
      else if (LocalFunction != LocalFunctionTemp)
        // This MDNode contains operands that are local to different functions.
        return false;
  }
    
  return true;
}

//===----------------------------------------------------------------------===//
// NamedMDNode implementation.
//
NamedMDNode::NamedMDNode(LLVMContext &C, const Twine &N,
                         MetadataBase *const *MDs, 
                         unsigned NumMDs, Module *ParentModule)
  : MetadataBase(Type::getMetadataTy(C), Value::NamedMDNodeVal), Parent(0) {
  setName(N);

  for (unsigned i = 0; i != NumMDs; ++i)
    Node.push_back(TrackingVH<MetadataBase>(MDs[i]));

  if (ParentModule)
    ParentModule->getNamedMDList().push_back(this);
}

NamedMDNode *NamedMDNode::Create(const NamedMDNode *NMD, Module *M) {
  assert(NMD && "Invalid source NamedMDNode!");
  SmallVector<MetadataBase *, 4> Elems;
  for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i)
    Elems.push_back(NMD->getElement(i));
  return new NamedMDNode(NMD->getContext(), NMD->getName().data(),
                         Elems.data(), Elems.size(), M);
}

/// eraseFromParent - Drop all references and remove the node from parent
/// module.
void NamedMDNode::eraseFromParent() {
  getParent()->getNamedMDList().erase(this);
}

/// dropAllReferences - Remove all uses and clear node vector.
void NamedMDNode::dropAllReferences() {
  Node.clear();
}

NamedMDNode::~NamedMDNode() {
  dropAllReferences();
}

//===----------------------------------------------------------------------===//
// MetadataContextImpl implementation.
//
namespace llvm {
class MetadataContextImpl {
public:
  typedef std::pair<unsigned, TrackingVH<MDNode> > MDPairTy;
  typedef SmallVector<MDPairTy, 2> MDMapTy;
  typedef DenseMap<const Instruction *, MDMapTy> MDStoreTy;
  friend class BitcodeReader;
private:

  /// MetadataStore - Collection of metadata used in this context.
  MDStoreTy MetadataStore;

  /// MDHandlerNames - Map to hold metadata handler names.
  StringMap<unsigned> MDHandlerNames;

public:
  /// registerMDKind - Register a new metadata kind and return its ID.
  /// A metadata kind can be registered only once. 
  unsigned registerMDKind(StringRef Name);

  /// getMDKind - Return metadata kind. If the requested metadata kind
  /// is not registered then return 0.
  unsigned getMDKind(StringRef Name) const;

  /// getMD - Get the metadata of given kind attached to an Instruction.
  /// If the metadata is not found then return 0.
  MDNode *getMD(unsigned Kind, const Instruction *Inst);

  /// getMDs - Get the metadata attached to an Instruction.
  void getMDs(const Instruction *Inst, SmallVectorImpl<MDPairTy> &MDs) const;

  /// addMD - Attach the metadata of given kind to an Instruction.
  void addMD(unsigned Kind, MDNode *Node, Instruction *Inst);
  
  /// removeMD - Remove metadata of given kind attached with an instruction.
  void removeMD(unsigned Kind, Instruction *Inst);
  
  /// removeAllMetadata - Remove all metadata attached with an instruction.
  void removeAllMetadata(Instruction *Inst);

  /// copyMD - If metadata is attached with Instruction In1 then attach
  /// the same metadata to In2.
  void copyMD(Instruction *In1, Instruction *In2);

  /// getHandlerNames - Populate client-supplied smallvector using custom
  /// metadata name and ID.
  void getHandlerNames(SmallVectorImpl<std::pair<unsigned, StringRef> >&) const;

  /// ValueIsDeleted - This handler is used to update metadata store
  /// when a value is deleted.
  void ValueIsDeleted(const Value *) {}
  void ValueIsDeleted(Instruction *Inst) {
    removeAllMetadata(Inst);
  }
  void ValueIsRAUWd(Value *V1, Value *V2);

  /// ValueIsCloned - This handler is used to update metadata store
  /// when In1 is cloned to create In2.
  void ValueIsCloned(const Instruction *In1, Instruction *In2);
};
}

/// registerMDKind - Register a new metadata kind and return its ID.
/// A metadata kind can be registered only once. 
unsigned MetadataContextImpl::registerMDKind(StringRef Name) {
  unsigned Count = MDHandlerNames.size();
  assert(MDHandlerNames.count(Name) == 0 && "Already registered MDKind!");
  return MDHandlerNames[Name] = Count + 1;
}

/// getMDKind - Return metadata kind. If the requested metadata kind
/// is not registered then return 0.
unsigned MetadataContextImpl::getMDKind(StringRef Name) const {
  StringMap<unsigned>::const_iterator I = MDHandlerNames.find(Name);
  if (I == MDHandlerNames.end())
    return 0;

  return I->getValue();
}

/// addMD - Attach the metadata of given kind to an Instruction.
void MetadataContextImpl::addMD(unsigned MDKind, MDNode *Node, 
                                Instruction *Inst) {
  assert(Node && "Invalid null MDNode");
  Inst->HasMetadata = true;
  MDMapTy &Info = MetadataStore[Inst];
  if (Info.empty()) {
    Info.push_back(std::make_pair(MDKind, Node));
    MetadataStore.insert(std::make_pair(Inst, Info));
    return;
  }

  // If there is an entry for this MDKind then replace it.
  for (unsigned i = 0, e = Info.size(); i != e; ++i) {
    MDPairTy &P = Info[i];
    if (P.first == MDKind) {
      Info[i] = std::make_pair(MDKind, Node);
      return;
    }
  }

  // Otherwise add a new entry.
  Info.push_back(std::make_pair(MDKind, Node));
}

/// removeMD - Remove metadata of given kind attached with an instruction.
void MetadataContextImpl::removeMD(unsigned Kind, Instruction *Inst) {
  MDStoreTy::iterator I = MetadataStore.find(Inst);
  if (I == MetadataStore.end())
    return;

  MDMapTy &Info = I->second;
  for (MDMapTy::iterator MI = Info.begin(), ME = Info.end(); MI != ME; ++MI) {
    MDPairTy &P = *MI;
    if (P.first == Kind) {
      Info.erase(MI);
      return;
    }
  }
}

/// removeAllMetadata - Remove all metadata attached with an instruction.
void MetadataContextImpl::removeAllMetadata(Instruction *Inst) {
  MetadataStore.erase(Inst);
  Inst->HasMetadata = false;
}

/// copyMD - If metadata is attached with Instruction In1 then attach
/// the same metadata to In2.
void MetadataContextImpl::copyMD(Instruction *In1, Instruction *In2) {
  assert(In1 && In2 && "Invalid instruction!");
  MDMapTy &In1Info = MetadataStore[In1];
  if (In1Info.empty())
    return;

  for (MDMapTy::iterator I = In1Info.begin(), E = In1Info.end(); I != E; ++I)
    addMD(I->first, I->second, In2);
}

/// getMD - Get the metadata of given kind attached to an Instruction.
/// If the metadata is not found then return 0.
MDNode *MetadataContextImpl::getMD(unsigned MDKind, const Instruction *Inst) {
  MDMapTy &Info = MetadataStore[Inst];
  if (Info.empty())
    return NULL;

  for (MDMapTy::iterator I = Info.begin(), E = Info.end(); I != E; ++I)
    if (I->first == MDKind)
      return I->second;
  return NULL;
}

/// getMDs - Get the metadata attached to an Instruction.
void MetadataContextImpl::
getMDs(const Instruction *Inst, SmallVectorImpl<MDPairTy> &MDs) const {
  MDStoreTy::const_iterator I = MetadataStore.find(Inst);
  if (I == MetadataStore.end())
    return;
  MDs.resize(I->second.size());
  for (MDMapTy::const_iterator MI = I->second.begin(), ME = I->second.end();
       MI != ME; ++MI)
    // MD kinds are numbered from 1.
    MDs[MI->first - 1] = std::make_pair(MI->first, MI->second);
}

/// getHandlerNames - Populate client supplied smallvector using custome
/// metadata name and ID.
void MetadataContextImpl::
getHandlerNames(SmallVectorImpl<std::pair<unsigned, StringRef> >&Names) const {
  Names.resize(MDHandlerNames.size());
  for (StringMap<unsigned>::const_iterator I = MDHandlerNames.begin(),
         E = MDHandlerNames.end(); I != E; ++I) 
    // MD Handlers are numbered from 1.
    Names[I->second - 1] = std::make_pair(I->second, I->first());
}

/// ValueIsCloned - This handler is used to update metadata store
/// when In1 is cloned to create In2.
void MetadataContextImpl::ValueIsCloned(const Instruction *In1, 
                                        Instruction *In2) {
  // Find Metadata handles for In1.
  MDStoreTy::iterator I = MetadataStore.find(In1);
  assert(I != MetadataStore.end() && "Invalid custom metadata info!");

  // FIXME : Give all metadata handlers a chance to adjust.

  MDMapTy &In1Info = I->second;
  MDMapTy In2Info;
  for (MDMapTy::iterator I = In1Info.begin(), E = In1Info.end(); I != E; ++I)
    addMD(I->first, I->second, In2);
}

/// ValueIsRAUWd - This handler is used when V1's all uses are replaced by
/// V2.
void MetadataContextImpl::ValueIsRAUWd(Value *V1, Value *V2) {
  Instruction *I1 = dyn_cast<Instruction>(V1);
  Instruction *I2 = dyn_cast<Instruction>(V2);
  if (!I1 || !I2)
    return;

  // FIXME : Give custom handlers a chance to override this.
  ValueIsCloned(I1, I2);
}

//===----------------------------------------------------------------------===//
// MetadataContext implementation.
//
MetadataContext::MetadataContext() 
  : pImpl(new MetadataContextImpl()) { }
MetadataContext::~MetadataContext() { delete pImpl; }

/// isValidName - Return true if Name is a valid custom metadata handler name.
bool MetadataContext::isValidName(StringRef MDName) {
  if (MDName.empty())
    return false;

  if (!isalpha(MDName[0]))
    return false;

  for (StringRef::iterator I = MDName.begin() + 1, E = MDName.end(); I != E;
       ++I) {
    if (!isalnum(*I) && *I != '_' && *I != '-' && *I != '.')
        return false;
  }
  return true;
}

/// registerMDKind - Register a new metadata kind and return its ID.
/// A metadata kind can be registered only once. 
unsigned MetadataContext::registerMDKind(StringRef Name) {
  assert(isValidName(Name) && "Invalid custome metadata name!");
  return pImpl->registerMDKind(Name);
}

/// getMDKind - Return metadata kind. If the requested metadata kind
/// is not registered then return 0.
unsigned MetadataContext::getMDKind(StringRef Name) const {
  return pImpl->getMDKind(Name);
}

/// getMD - Get the metadata of given kind attached to an Instruction.
/// If the metadata is not found then return 0.
MDNode *MetadataContext::getMD(unsigned Kind, const Instruction *Inst) {
  return pImpl->getMD(Kind, Inst);
}

/// getMDs - Get the metadata attached to an Instruction.
void MetadataContext::
getMDs(const Instruction *Inst, 
       SmallVectorImpl<std::pair<unsigned, TrackingVH<MDNode> > > &MDs) const {
  return pImpl->getMDs(Inst, MDs);
}

/// addMD - Attach the metadata of given kind to an Instruction.
void MetadataContext::addMD(unsigned Kind, MDNode *Node, Instruction *Inst) {
  pImpl->addMD(Kind, Node, Inst);
}

/// removeMD - Remove metadata of given kind attached with an instruction.
void MetadataContext::removeMD(unsigned Kind, Instruction *Inst) {
  pImpl->removeMD(Kind, Inst);
}

/// removeAllMetadata - Remove all metadata attached with an instruction.
void MetadataContext::removeAllMetadata(Instruction *Inst) {
  pImpl->removeAllMetadata(Inst);
}

/// copyMD - If metadata is attached with Instruction In1 then attach
/// the same metadata to In2.
void MetadataContext::copyMD(Instruction *In1, Instruction *In2) {
  pImpl->copyMD(In1, In2);
}

/// getHandlerNames - Populate client supplied smallvector using custome
/// metadata name and ID.
void MetadataContext::
getHandlerNames(SmallVectorImpl<std::pair<unsigned, StringRef> >&N) const {
  pImpl->getHandlerNames(N);
}

/// ValueIsDeleted - This handler is used to update metadata store
/// when a value is deleted.
void MetadataContext::ValueIsDeleted(Instruction *Inst) {
  pImpl->ValueIsDeleted(Inst);
}
void MetadataContext::ValueIsRAUWd(Value *V1, Value *V2) {
  pImpl->ValueIsRAUWd(V1, V2);
}

/// ValueIsCloned - This handler is used to update metadata store
/// when In1 is cloned to create In2.
void MetadataContext::ValueIsCloned(const Instruction *In1, Instruction *In2) {
  pImpl->ValueIsCloned(In1, In2);
}