/// takeName - transfer the name from V to this value, setting V's name to
/// empty.  It is an error to call V->takeName(V).
void Value::takeName(Value *V) {
  ValueSymbolTable *ST = 0;
  // If this value has a name, drop it.
  if (hasName()) {
    // Get the symtab this is in.
    if (getSymTab(this, ST)) {
      // We can't set a name on this value, but we need to clear V's name if
      // it has one.
      if (V->hasName()) V->setName("");
      return;  // Cannot set a name on this value (e.g. constant).
    }

    // Remove old name.
    if (ST)
      ST->removeValueName(Name);
    Name->Destroy();
    Name = 0;
  }

  // Now we know that this has no name.

  // If V has no name either, we're done.
  if (!V->hasName()) return;

  // Get this's symtab if we didn't before.
  if (!ST) {
    if (getSymTab(this, ST)) {
      // Clear V's name.
      V->setName("");
      return;  // Cannot set a name on this value (e.g. constant).
    }
  }

  // Get V's ST, this should always succed, because V has a name.
  ValueSymbolTable *VST;
  bool Failure = getSymTab(V, VST);
  assert(!Failure && "V has a name, so it should have a ST!"); Failure=Failure;

  // If these values are both in the same symtab, we can do this very fast.
  // This works even if both values have no symtab yet.
  if (ST == VST) {
    // Take the name!
    Name = V->Name;
    V->Name = 0;
    Name->setValue(this);
    return;
  }

  // Otherwise, things are slightly more complex.  Remove V's name from VST and
  // then reinsert it into ST.

  if (VST)
    VST->removeValueName(V->Name);
  Name = V->Name;
  V->Name = 0;
  Name->setValue(this);

  if (ST)
    ST->reinsertValue(this);
}

void Value::setName(const Twine &NewName) {
  // Fast path for common IRBuilder case of setName("") when there is no name.
  if (NewName.isTriviallyEmpty() && !hasName())
    return;

  SmallString<256> NameData;
  NewName.toVector(NameData);

  const char *NameStr = NameData.data();
  unsigned NameLen = NameData.size();

  // Name isn't changing?
  if (getName() == StringRef(NameStr, NameLen))
    return;

  assert(getType() != Type::getVoidTy(getContext()) &&
         "Cannot assign a name to void values!");

  // Get the symbol table to update for this object.
  ValueSymbolTable *ST;
  if (getSymTab(this, ST))
    return;  // Cannot set a name on this value (e.g. constant).

  if (!ST) { // No symbol table to update?  Just do the change.
    if (NameLen == 0) {
      // Free the name for this value.
      Name->Destroy();
      Name = 0;
      return;
    }

    if (Name)
      Name->Destroy();

    // NOTE: Could optimize for the case the name is shrinking to not deallocate
    // then reallocated.

    // Create the new name.
    Name = ValueName::Create(NameStr, NameStr+NameLen);
    Name->setValue(this);
    return;
  }

  // NOTE: Could optimize for the case the name is shrinking to not deallocate
  // then reallocated.
  if (hasName()) {
    // Remove old name.
    ST->removeValueName(Name);
    Name->Destroy();
    Name = 0;

    if (NameLen == 0)
      return;
  }

  // Name is changing to something new.
  Name = ST->createValueName(StringRef(NameStr, NameLen), this);
}

// Emit names for globals/functions etc.
static void WriteValueSymbolTable(const ValueSymbolTable &VST,
                                  const NaClValueEnumerator &VE,
                                  NaClBitstreamWriter &Stream) {
  if (VST.empty()) return;
  Stream.EnterSubblock(naclbitc::VALUE_SYMTAB_BLOCK_ID);

  // FIXME: Set up the abbrev, we know how many values there are!
  // FIXME: We know if the type names can use 7-bit ascii.
  SmallVector<unsigned, 64> NameVals;

  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
       SI != SE; ++SI) {
    if (VE.IsElidedCast(SI->getValue())) continue;

    const ValueName &Name = *SI;

    // Figure out the encoding to use for the name.
    bool is7Bit = true;
    bool isChar6 = true;
    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
         C != E; ++C) {
      if (isChar6)
        isChar6 = NaClBitCodeAbbrevOp::isChar6(*C);
      if ((unsigned char)*C & 128) {
        is7Bit = false;
        break;  // don't bother scanning the rest.
      }
    }

    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;

    // VST_ENTRY:   [valueid, namechar x N]
    // VST_BBENTRY: [bbid, namechar x N]
    unsigned Code;
    if (isa<BasicBlock>(SI->getValue())) {
      Code = naclbitc::VST_CODE_BBENTRY;
      if (isChar6)
        AbbrevToUse = VST_BBENTRY_6_ABBREV;
    } else {
      Code = naclbitc::VST_CODE_ENTRY;
      if (isChar6)
        AbbrevToUse = VST_ENTRY_6_ABBREV;
      else if (is7Bit)
        AbbrevToUse = VST_ENTRY_7_ABBREV;
    }

    NameVals.push_back(VE.getValueID(SI->getValue()));
    for (const char *P = Name.getKeyData(),
         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
      NameVals.push_back((unsigned char)*P);

    // Emit the finished record.
    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
    NameVals.clear();
  }
  Stream.ExitBlock();
}

void Value::setName(const Twine &NewName) {
  assert(SubclassID != MDStringVal &&
         "Cannot set the name of MDString with this method!");

  // Fast path for common IRBuilder case of setName("") when there is no name.
  if (NewName.isTriviallyEmpty() && !hasName())
    return;

  SmallString<256> NameData;
  StringRef NameRef = NewName.toStringRef(NameData);

  // Name isn't changing?
  if (getName() == NameRef)
    return;

  assert(!getType()->isVoidTy() && "Cannot assign a name to void values!");

  // Get the symbol table to update for this object.
  ValueSymbolTable *ST;
  if (getSymTab(this, ST))
    return;  // Cannot set a name on this value (e.g. constant).

  if (!ST) { // No symbol table to update?  Just do the change.
    if (NameRef.empty()) {
      // Free the name for this value.
      Name->Destroy();
      Name = 0;
      return;
    }

    if (Name)
      Name->Destroy();

    // NOTE: Could optimize for the case the name is shrinking to not deallocate
    // then reallocated.

    // Create the new name.
    Name = ValueName::Create(NameRef.begin(), NameRef.end());
    Name->setValue(this);
    return;
  }

  // NOTE: Could optimize for the case the name is shrinking to not deallocate
  // then reallocated.
  if (hasName()) {
    // Remove old name.
    ST->removeValueName(Name);
    Name->Destroy();
    Name = 0;

    if (NameRef.empty())
      return;
  }

  // Name is changing to something new.
  Name = ST->createValueName(NameRef, this);
}

void Value::setNameImpl(const Twine &NewName) {
  // Fast-path: LLVMContext can be set to strip out non-GlobalValue names
  if (getContext().shouldDiscardValueNames() && !isa<GlobalValue>(this))
    return;

  // Fast path for common IRBuilder case of setName("") when there is no name.
  if (NewName.isTriviallyEmpty() && !hasName())
    return;

  SmallString<256> NameData;
  StringRef NameRef = NewName.toStringRef(NameData);
  assert(NameRef.find_first_of(0) == StringRef::npos &&
         "Null bytes are not allowed in names");

  // Name isn't changing?
  if (getName() == NameRef)
    return;

  assert(!getType()->isVoidTy() && "Cannot assign a name to void values!");

  // Get the symbol table to update for this object.
  ValueSymbolTable *ST;
  if (getSymTab(this, ST))
    return;  // Cannot set a name on this value (e.g. constant).

  if (!ST) { // No symbol table to update?  Just do the change.
    if (NameRef.empty()) {
      // Free the name for this value.
      destroyValueName();
      return;
    }

    // NOTE: Could optimize for the case the name is shrinking to not deallocate
    // then reallocated.
    destroyValueName();

    // Create the new name.
    setValueName(ValueName::Create(NameRef));
    getValueName()->setValue(this);
    return;
  }

  // NOTE: Could optimize for the case the name is shrinking to not deallocate
  // then reallocated.
  if (hasName()) {
    // Remove old name.
    ST->removeValueName(getValueName());
    destroyValueName();

    if (NameRef.empty())
      return;
  }

  // Name is changing to something new.
  setValueName(ST->createValueName(NameRef, this));
}

// Strip the symbol table of its names.
//
static void StripSymtab(ValueSymbolTable &ST, bool PreserveDbgInfo) {
  for (ValueSymbolTable::iterator VI = ST.begin(), VE = ST.end(); VI != VE; ) {
    Value *V = VI->getValue();
    ++VI;
    if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasLocalLinkage()) {
      if (!PreserveDbgInfo || !V->getName().startswith("llvm.dbg"))
        // Set name to "", removing from symbol table!
        V->setName("");
    }
  }
}

void Value::setName(const char *NameStr, unsigned NameLen) {
  if (NameLen == 0 && !hasName()) return;
  assert(getType() != Type::VoidTy && "Cannot assign a name to void values!");
  
  // Get the symbol table to update for this object.
  ValueSymbolTable *ST;
  if (getSymTab(this, ST))
    return;  // Cannot set a name on this value (e.g. constant).

  if (!ST) { // No symbol table to update?  Just do the change.
    if (NameLen == 0) {
      // Free the name for this value.
      Name->Destroy();
      Name = 0;
      return;
    }
    
    if (Name) {
      // Name isn't changing?
      if (NameLen == Name->getKeyLength() &&
          !memcmp(Name->getKeyData(), NameStr, NameLen))
        return;
      Name->Destroy();
    }
    
    // NOTE: Could optimize for the case the name is shrinking to not deallocate
    // then reallocated.
      
    // Create the new name.
    Name = ValueName::Create(NameStr, NameStr+NameLen);
    Name->setValue(this);
    return;
  }
  
  // NOTE: Could optimize for the case the name is shrinking to not deallocate
  // then reallocated.
  if (hasName()) {
    // Name isn't changing?
    if (NameLen == Name->getKeyLength() &&
        !memcmp(Name->getKeyData(), NameStr, NameLen))
      return;

    // Remove old name.
    ST->removeValueName(Name);
    Name->Destroy();
    Name = 0;

    if (NameLen == 0)
      return;
  }

  // Name is changing to something new.
  Name = ST->createValueName(NameStr, NameLen, this);
}

/// EnumerateValueSymbolTable - Insert all of the values in the specified symbol
/// table into the values table.
void ValueEnumerator::EnumerateValueSymbolTable(const ValueSymbolTable &VST) {
  for (ValueSymbolTable::const_iterator VI = VST.begin(), VE = VST.end();
       VI != VE; ++VI)
    EnumerateValue(VI->getValue());
}

void Value::setName(const Twine &NewName) {
  assert(SubclassID != MDStringVal &&
         "Cannot set the name of MDString with this method!");

  // Fast path for common IRBuilder case of setName("") when there is no name.
  if (NewName.isTriviallyEmpty() && !hasName())
    return;

  SmallString<256> NameData;
  StringRef NameRef = NewName.toStringRef(NameData);
  assert(NameRef.find_first_of(0) == StringRef::npos &&
         "Null bytes are not allowed in names");

  // Name isn't changing?
  if (getName() == NameRef)
    return;

  assert(!getType()->isVoidTy() && "Cannot assign a name to void values!");

  // Get the symbol table to update for this object.
  ValueSymbolTable *ST;
  if (getSymTab(this, ST))
    return;  // Cannot set a name on this value (e.g. constant).

  if (Function *F = dyn_cast<Function>(this))
    getContext().pImpl->IntrinsicIDCache.erase(F);

  if (!ST) { // No symbol table to update?  Just do the change.
    if (NameRef.empty()) {
      // Free the name for this value.
      Name->Destroy();
      Name = nullptr;
      return;
    }

    if (Name)
      Name->Destroy();

    // NOTE: Could optimize for the case the name is shrinking to not deallocate
    // then reallocated.

    // Create the new name.
    Name = ValueName::Create(NameRef);
    Name->setValue(this);
    return;
  }

  // NOTE: Could optimize for the case the name is shrinking to not deallocate
  // then reallocated.
  if (hasName()) {
    // Remove old name.
    ST->removeValueName(Name);
    Name->Destroy();
    Name = nullptr;

    if (NameRef.empty())
      return;
  }

  // Name is changing to something new.
  Name = ST->createValueName(NameRef, this);
}