C++ BitsInit::setBit方法代码示例

void CodeEmitterGen::reverseBits(std::vector<Record*> &Insts) {
  for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
       I != E; ++I) {
    Record *R = *I;
    if (R->getName() == "PHI" ||
        R->getName() == "INLINEASM" ||
        R->getName() == "DBG_LABEL" ||
        R->getName() == "EH_LABEL" ||
        R->getName() == "GC_LABEL" ||
        R->getName() == "KILL" ||
        R->getName() == "EXTRACT_SUBREG" ||
        R->getName() == "INSERT_SUBREG" ||
        R->getName() == "IMPLICIT_DEF" ||
        R->getName() == "SUBREG_TO_REG" ||
        R->getName() == "COPY_TO_REGCLASS" ||
        R->getName() == "DBG_VALUE") continue;

    BitsInit *BI = R->getValueAsBitsInit("Inst");

    unsigned numBits = BI->getNumBits();
    BitsInit *NewBI = new BitsInit(numBits);
    for (unsigned bit = 0, end = numBits / 2; bit != end; ++bit) {
      unsigned bitSwapIdx = numBits - bit - 1;
      Init *OrigBit = BI->getBit(bit);
      Init *BitSwap = BI->getBit(bitSwapIdx);
      NewBI->setBit(bit, BitSwap);
      NewBI->setBit(bitSwapIdx, OrigBit);
    }
    if (numBits % 2) {
      unsigned middle = (numBits + 1) / 2;
      NewBI->setBit(middle, BI->getBit(middle));
    }
    
    // Update the bits in reversed order so that emitInstrOpBits will get the
    // correct endianness.
    R->getValue("Inst")->setValue(NewBI);
  }
}

/// SetValue -
/// Return true on error, false on success.
bool TGParser::SetValue(Record *CurRec, TGLoc Loc, const std::string &ValName, 
                        const std::vector<unsigned> &BitList, Init *V) {
  if (!V) return false;

  if (CurRec == 0) CurRec = &CurMultiClass->Rec;

  RecordVal *RV = CurRec->getValue(ValName);
  if (RV == 0)
    return Error(Loc, "Value '" + ValName + "' unknown!");

  // Do not allow assignments like 'X = X'.  This will just cause infinite loops
  // in the resolution machinery.
  if (BitList.empty())
    if (VarInit *VI = dynamic_cast<VarInit*>(V))
      if (VI->getName() == ValName)
        return false;
  
  // If we are assigning to a subset of the bits in the value... then we must be
  // assigning to a field of BitsRecTy, which must have a BitsInit
  // initializer.
  //
  if (!BitList.empty()) {
    BitsInit *CurVal = dynamic_cast<BitsInit*>(RV->getValue());
    if (CurVal == 0)
      return Error(Loc, "Value '" + ValName + "' is not a bits type");

    // Convert the incoming value to a bits type of the appropriate size...
    Init *BI = V->convertInitializerTo(new BitsRecTy(BitList.size()));
    if (BI == 0) {
      V->convertInitializerTo(new BitsRecTy(BitList.size()));
      return Error(Loc, "Initializer is not compatible with bit range");
    }
                   
    // We should have a BitsInit type now.
    BitsInit *BInit = dynamic_cast<BitsInit*>(BI);
    assert(BInit != 0);

    BitsInit *NewVal = new BitsInit(CurVal->getNumBits());

    // Loop over bits, assigning values as appropriate.
    for (unsigned i = 0, e = BitList.size(); i != e; ++i) {
      unsigned Bit = BitList[i];
      if (NewVal->getBit(Bit))
        return Error(Loc, "Cannot set bit #" + utostr(Bit) + " of value '" +
                     ValName + "' more than once");
      NewVal->setBit(Bit, BInit->getBit(i));
    }

    for (unsigned i = 0, e = CurVal->getNumBits(); i != e; ++i)
      if (NewVal->getBit(i) == 0)
        NewVal->setBit(i, CurVal->getBit(i));

    V = NewVal;
  }

  if (RV->setValue(V))
   return Error(Loc, "Value '" + ValName + "' of type '" + 
                RV->getType()->getAsString() + 
                "' is incompatible with initializer '" + V->getAsString() +"'");
  return false;
}

//.........这里部分代码省略.........
    SCRef.TemplateArgs = ValueList;
    // Add info about the subclass to NewRec.
    if (AddSubClass(NewRec, SCRef))
      return 0;
    NewRec->resolveReferences();
    Records.addDef(NewRec);
    
    // The result of the expression is a reference to the new record.
    return new DefInit(NewRec);
  }    
  case tgtok::l_brace: {           // Value ::= '{' ValueList '}'
    TGLoc BraceLoc = Lex.getLoc();
    Lex.Lex(); // eat the '{'
    std::vector<Init*> Vals;
    
    if (Lex.getCode() != tgtok::r_brace) {
      Vals = ParseValueList(CurRec);
      if (Vals.empty()) return 0;
    }
    if (Lex.getCode() != tgtok::r_brace) {
      TokError("expected '}' at end of bit list value");
      return 0;
    }
    Lex.Lex();  // eat the '}'
    
    BitsInit *Result = new BitsInit(Vals.size());
    for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
      Init *Bit = Vals[i]->convertInitializerTo(new BitRecTy());
      if (Bit == 0) {
        Error(BraceLoc, "Element #" + utostr(i) + " (" + Vals[i]->getAsString()+
              ") is not convertable to a bit");
        return 0;
      }
      Result->setBit(Vals.size()-i-1, Bit);
    }
    return Result;
  }
  case tgtok::l_square: {          // Value ::= '[' ValueList ']'
    Lex.Lex(); // eat the '['
    std::vector<Init*> Vals;
    
    if (Lex.getCode() != tgtok::r_square) {
      Vals = ParseValueList(CurRec);
      if (Vals.empty()) return 0;
    }
    if (Lex.getCode() != tgtok::r_square) {
      TokError("expected ']' at end of list value");
      return 0;
    }
    Lex.Lex();  // eat the ']'
    return new ListInit(Vals);
  }
  case tgtok::l_paren: {         // Value ::= '(' IDValue DagArgList ')'
    Lex.Lex();   // eat the '('
    if (Lex.getCode() != tgtok::Id) {
      TokError("expected identifier in dag init");
      return 0;
    }
    
    Init *Operator = ParseIDValue(CurRec);
    if (Operator == 0) return 0;
    
    // If the operator name is present, parse it.
    std::string OperatorName;
    if (Lex.getCode() == tgtok::colon) {
      if (Lex.Lex() != tgtok::VarName) { // eat the ':'