// Test for and give an error if the node can't be read from.
void TParseContextBase::rValueErrorCheck(const TSourceLoc& loc, const char* op, TIntermTyped* node)
{
    if (! node)
        return;

    TIntermBinary* binaryNode = node->getAsBinaryNode();
    if (binaryNode) {
        switch(binaryNode->getOp()) {
        case EOpIndexDirect:
        case EOpIndexIndirect:
        case EOpIndexDirectStruct:
        case EOpVectorSwizzle:
        case EOpMatrixSwizzle:
            rValueErrorCheck(loc, op, binaryNode->getLeft());
        default:
            break;
        }

        return;
    }

    TIntermSymbol* symNode = node->getAsSymbolNode();
    if (symNode && symNode->getQualifier().writeonly)
        error(loc, "can't read from writeonly object: ", op, symNode->getName().c_str());
}

TIntermBinary *MakeNewBinary(TOperator op, TIntermTyped *left, TIntermTyped *right, const TType &resultType)
{
    TIntermBinary *binary = new TIntermBinary(op);
    binary->setLeft(left);
    binary->setRight(right);
    binary->setType(resultType);
    return binary;
}

TIntermBinary *TIntermTraverser::createTempAssignment(TIntermTyped *rightNode)
{
    ASSERT(rightNode != nullptr);
    TIntermSymbol *tempSymbol = createTempSymbol(rightNode->getType());
    TIntermBinary *assignment = new TIntermBinary(EOpAssign);
    assignment->setLeft(tempSymbol);
    assignment->setRight(rightNode);
    assignment->setType(tempSymbol->getType());
    return assignment;
}

int ForLoopUnroll::getLoopIncrement(TIntermLoop* node)
{
    TIntermNode* expr = node->getExpression();
    ASSERT(expr != NULL);
    // for expression has one of the following forms:
    //     loop_index++
    //     loop_index--
    //     loop_index += constant_expression
    //     loop_index -= constant_expression
    //     ++loop_index
    //     --loop_index
    // The last two forms are not specified in the spec, but I am assuming
    // its an oversight.
    TIntermUnary* unOp = expr->getAsUnaryNode();
    TIntermBinary* binOp = unOp ? NULL : expr->getAsBinaryNode();

    TOperator op = EOpNull;
    TIntermConstantUnion* incrementNode = NULL;
    if (unOp != NULL) {
        op = unOp->getOp();
    } else if (binOp != NULL) {
        op = binOp->getOp();
        ASSERT(binOp->getRight() != NULL);
        incrementNode = binOp->getRight()->getAsConstantUnion();
        ASSERT(incrementNode != NULL);
    }

    int increment = 0;
    // The operator is one of: ++ -- += -=.
    switch (op) {
        case EOpPostIncrement:
        case EOpPreIncrement:
            ASSERT((unOp != NULL) && (binOp == NULL));
            increment = 1;
            break;
        case EOpPostDecrement:
        case EOpPreDecrement:
            ASSERT((unOp != NULL) && (binOp == NULL));
            increment = -1;
            break;
        case EOpAddAssign:
            ASSERT((unOp == NULL) && (binOp != NULL));
            increment = evaluateIntConstant(incrementNode);
            break;
        case EOpSubAssign:
            ASSERT((unOp == NULL) && (binOp != NULL));
            increment = - evaluateIntConstant(incrementNode);
            break;
        default:
            ASSERT(false);
    }

    return increment;
}

//
// Connect two nodes through an index operator, where the left node is the base
// of an array or struct, and the right node is a direct or indirect offset.
//
// Returns the added node.
// The caller should set the type of the returned node.
//
TIntermTyped* TIntermediate::addIndex(TOperator op, TIntermTyped* base, TIntermTyped* index, const TSourceLoc& line)
{
    TIntermBinary* node = new TIntermBinary(op);
    node->setLine(line);
    node->setLeft(base);
    node->setRight(index);

    // caller should set the type

    return node;
}

// Connect two nodes through an index operator, where the left node is the base
// of an array or struct, and the right node is a direct or indirect offset.
//
// The caller should set the type of the returned node.
TIntermTyped* ir_add_index(TOperator op, TIntermTyped* base, TIntermTyped* index, TSourceLoc line)
{
	TIntermBinary* node = new TIntermBinary(op);
	if (line.line == 0)
		line = index->getLine();
	node->setLine(line);
	node->setLeft(base);
	node->setRight(index);

	// caller should set the type

	return node;
}

bool ValidateLimitations::validateForLoopCond(TIntermLoop *node,
                                              int indexSymbolId)
{
    TIntermNode *cond = node->getCondition();
    if (cond == NULL)
    {
        error(node->getLine(), "Missing condition", "for");
        return false;
    }
    //
    // condition has the form:
    //     loop_index relational_operator constant_expression
    //
    TIntermBinary *binOp = cond->getAsBinaryNode();
    if (binOp == NULL)
    {
        error(node->getLine(), "Invalid condition", "for");
        return false;
    }
    // Loop index should be to the left of relational operator.
    TIntermSymbol *symbol = binOp->getLeft()->getAsSymbolNode();
    if (symbol == NULL)
    {
        error(binOp->getLine(), "Invalid condition", "for");
        return false;
    }
    if (symbol->getId() != indexSymbolId)
    {
        error(symbol->getLine(),
              "Expected loop index", symbol->getSymbol().c_str());
        return false;
    }
    // Relational operator is one of: > >= < <= == or !=.
    switch (binOp->getOp())
    {
      case EOpEqual:
      case EOpNotEqual:
      case EOpLessThan:
      case EOpGreaterThan:
      case EOpLessThanEqual:
      case EOpGreaterThanEqual:
        break;
      default:
        error(binOp->getLine(),
              "Invalid relational operator",
              GetOperatorString(binOp->getOp()));
        break;
    }
    // Loop index must be compared with a constant.
    if (!isConstExpr(binOp->getRight()))
    {
        error(binOp->getLine(),
              "Loop index cannot be compared with non-constant expression",
              symbol->getSymbol().c_str());
        return false;
    }

    return true;
}

TString ScalarizeVecAndMatConstructorArgs::createTempVariable(TIntermTyped *original)
{
    TString tempVarName = "_webgl_tmp_";
    if (original->isScalar())
    {
        tempVarName += "scalar_";
    }
    else if (original->isVector())
    {
        tempVarName += "vec_";
    }
    else
    {
        ASSERT(original->isMatrix());
        tempVarName += "mat_";
    }
    tempVarName += Str(mTempVarCount).c_str();
    mTempVarCount++;

    ASSERT(original);
    TType type = original->getType();
    type.setQualifier(EvqTemporary);

    if (mShaderType == GL_FRAGMENT_SHADER &&
        type.getBasicType() == EbtFloat &&
        type.getPrecision() == EbpUndefined)
    {
        // We use the highest available precision for the temporary variable
        // to avoid computing the actual precision using the rules defined
        // in GLSL ES 1.0 Section 4.5.2.
        type.setPrecision(mFragmentPrecisionHigh ? EbpHigh : EbpMedium);
    }

    TIntermBinary *init = new TIntermBinary(EOpInitialize);
    TIntermSymbol *symbolNode = new TIntermSymbol(-1, tempVarName, type);
    init->setLeft(symbolNode);
    init->setRight(original);
    init->setType(type);

    TIntermAggregate *decl = new TIntermAggregate(EOpDeclaration);
    decl->getSequence()->push_back(init);

    ASSERT(mSequenceStack.size() > 0);
    TIntermSequence &sequence = mSequenceStack.back();
    sequence.push_back(decl);

    return tempVarName;
}

//
// Connect two nodes through an index operator, where the left node is the base
// of an array or struct, and the right node is a direct or indirect offset.
//
// Returns the added node.
// The caller should set the type of the returned node.
//
TIntermTyped *TIntermediate::addIndex(TOperator op,
                                      TIntermTyped *base,
                                      TIntermTyped *index,
                                      const TSourceLoc &line,
                                      TDiagnostics *diagnostics)
{
    TIntermBinary *node = new TIntermBinary(op, base, index);
    node->setLine(line);

    TIntermTyped *folded = node->fold(diagnostics);
    if (folded)
    {
        return folded;
    }

    return node;
}

bool FlagStd140Structs::isInStd140InterfaceBlock(TIntermTyped *node) const
{
    TIntermBinary *binaryNode = node->getAsBinaryNode();

    if (binaryNode)
    {
        return isInStd140InterfaceBlock(binaryNode->getLeft());
    }

    const TType &type = node->getType();

    // determine if we are in the standard layout
    const TInterfaceBlock *interfaceBlock = type.getInterfaceBlock();
    if (interfaceBlock)
    {
        return (interfaceBlock->blockStorage() == EbsStd140);
    }

    return false;
}

//
// Connect two nodes through an assignment.
//
// Returns the added node.
//
TIntermTyped *TIntermediate::addAssign(
    TOperator op, TIntermTyped *left, TIntermTyped *right, const TSourceLoc &line)
{
    if (left->getType().getStruct() || right->getType().getStruct())
    {
        if (left->getType() != right->getType())
        {
            return NULL;
        }
    }

    TIntermBinary *node = new TIntermBinary(op);
    node->setLine(line);

    node->setLeft(left);
    node->setRight(right);
    if (!node->promote(mInfoSink))
        return NULL;

    return node;
}

void TLoopIndexInfo::fillInfo(TIntermLoop *node)
{
    if (node == NULL)
        return;

    // Here we assume all the operations are valid, because the loop node is
    // already validated in ValidateLimitations.
    TIntermSequence *declSeq =
        node->getInit()->getAsAggregate()->getSequence();
    TIntermBinary *declInit = (*declSeq)[0]->getAsBinaryNode();
    TIntermSymbol *symbol = declInit->getLeft()->getAsSymbolNode();

    mId = symbol->getId();
    mType = symbol->getBasicType();

    if (mType == EbtInt)
    {
        TIntermConstantUnion* initNode = declInit->getRight()->getAsConstantUnion();
        mInitValue = EvaluateIntConstant(initNode);
        mCurrentValue = mInitValue;
        mIncrementValue = GetLoopIntIncrement(node);

        TIntermBinary* binOp = node->getCondition()->getAsBinaryNode();
        mStopValue = EvaluateIntConstant(
            binOp->getRight()->getAsConstantUnion());
        mOp = binOp->getOp();
    }
}

//
// Connect two nodes with a new parent that does a binary operation on the nodes.
//
// Returns the added node.
//
TIntermTyped *TIntermediate::addBinaryMath(
    TOperator op, TIntermTyped *left, TIntermTyped *right, const TSourceLoc &line)
{
    //
    // Need a new node holding things together then.  Make
    // one and promote it to the right type.
    //
    TIntermBinary *node = new TIntermBinary(op);
    node->setLine(line);

    node->setLeft(left);
    node->setRight(right);
    if (!node->promote(mInfoSink))
        return NULL;

    //
    // See if we can fold constants.
    //
    TIntermConstantUnion *leftTempConstant = left->getAsConstantUnion();
    TIntermConstantUnion *rightTempConstant = right->getAsConstantUnion();
    if (leftTempConstant && rightTempConstant)
    {
        TIntermTyped *typedReturnNode =
            leftTempConstant->fold(node->getOp(), rightTempConstant, mInfoSink);

        if (typedReturnNode)
            return typedReturnNode;
    }

    return node;
}

// Check if the tree starting at node corresponds to exp2(y * log2(x))
// If the tree matches, set base to the node corresponding to x.
bool IsPowWorkaround(TIntermNode *node, TIntermNode **base)
{
    TIntermUnary *exp = node->getAsUnaryNode();
    if (exp != nullptr && exp->getOp() == EOpExp2)
    {
        TIntermBinary *mul = exp->getOperand()->getAsBinaryNode();
        if (mul != nullptr && mul->isMultiplication())
        {
            TIntermUnary *log = mul->getRight()->getAsUnaryNode();
            if (mul->getLeft()->getAsConstantUnion() && log != nullptr)
            {
                if (log->getOp() == EOpLog2)
                {
                    if (base)
                        *base = log->getOperand();
                    return true;
                }
            }
        }
    }
    return false;
}

// Connect two nodes through an assignment.
TIntermTyped* ir_add_assign(TOperator op, TIntermTyped* left, TIntermTyped* right, TSourceLoc line, TParseContext& ctx)
{
   //
   // Like adding binary math, except the conversion can only go
   // from right to left.
   //
   TIntermBinary* node = new TIntermBinary(op);
   if (line.line == 0)
      line = left->getLine();
   node->setLine(line);

   TIntermTyped* child = ir_add_conversion(op, left->getType(), right, ctx.infoSink);
   if (child == 0)
      return 0;

   node->setLeft(left);
   node->setRight(child);
   if (! node->promote(ctx))
      return 0;

   return node;
}

void TSamplerTraverser::typeSampler( TIntermTyped *node, TBasicType samp )
{
   TIntermSymbol *symNode = node->getAsSymbolNode();

   if ( !symNode)
   {
      //TODO: add logic to handle sampler arrays and samplers as struct members

      //Don't try typing this one, it is a complex expression
      TIntermBinary *biNode = node->getAsBinaryNode();

      if ( biNode )
      {
         switch (biNode->getOp())
         {
         case EOpIndexDirect:
         case EOpIndexIndirect:
            infoSink.info << "Warning: " << node->getLine() <<  ": typing of sampler arrays presently unsupported\n";
            break;

         case EOpIndexDirectStruct:
            infoSink.info << "Warning: " << node->getLine() <<  ": typing of samplers as struct members presently unsupported\n";
            break;
         }
      }
      else
      {
         infoSink.info << "Warning: " << node->getLine() <<  ": unexpected expression type for sampler, cannot type\n";
      }
      abort = false;
   }
   else
   {
      // We really have something to type, abort this traverse and activate typing
      abort = true;
      id = symNode->getId();
      sampType = samp;
   }
}

// Special case for matrix[idx1][idx2]: output as matrix[idx2][idx1]
static bool Check2DMatrixIndex (TGlslOutputTraverser* goit, std::stringstream& out, TIntermTyped* left, TIntermTyped* right)
{
	if (left->isVector() && !left->isArray())
	{
		TIntermBinary* leftBin = left->getAsBinaryNode();
		if (leftBin && (leftBin->getOp() == EOpIndexDirect || leftBin->getOp() == EOpIndexIndirect))
		{
			TIntermTyped* superLeft = leftBin->getLeft();
			TIntermTyped* superRight = leftBin->getRight();
			if (superLeft->isMatrix() && !superLeft->isArray())
			{
				superLeft->traverse (goit);
				out << "[";
				right->traverse(goit);
				out << "][";
				superRight->traverse(goit);
				out << "]";
				return true;
			}
		}
	}
	return false;
}

int ValidateLimitations::validateForLoopInit(TIntermLoop *node)
{
    TIntermNode *init = node->getInit();
    if (init == NULL)
    {
        error(node->getLine(), "Missing init declaration", "for");
        return -1;
    }

    //
    // init-declaration has the form:
    //     type-specifier identifier = constant-expression
    //
    TIntermAggregate *decl = init->getAsAggregate();
    if ((decl == NULL) || (decl->getOp() != EOpDeclaration))
    {
        error(init->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    // To keep things simple do not allow declaration list.
    TIntermSequence &declSeq = decl->getSequence();
    if (declSeq.size() != 1)
    {
        error(decl->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    TIntermBinary *declInit = declSeq[0]->getAsBinaryNode();
    if ((declInit == NULL) || (declInit->getOp() != EOpInitialize))
    {
        error(decl->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    TIntermSymbol *symbol = declInit->getLeft()->getAsSymbolNode();
    if (symbol == NULL)
    {
        error(declInit->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    // The loop index has type int or float.
    TBasicType type = symbol->getBasicType();
    if ((type != EbtInt) && (type != EbtFloat))
    {
        error(symbol->getLine(),
              "Invalid type for loop index", getBasicString(type));
        return -1;
    }
    // The loop index is initialized with constant expression.
    if (!isConstExpr(declInit->getRight()))
    {
        error(declInit->getLine(),
              "Loop index cannot be initialized with non-constant expression",
              symbol->getSymbol().c_str());
        return -1;
    }

    return symbol->getId();
}

void InitializeVariables::insertInitCode(TIntermSequence *sequence)
{
    for (size_t ii = 0; ii < mVariables.size(); ++ii)
    {
        const InitVariableInfo &varInfo = mVariables[ii];

        if (varInfo.type.isArray())
        {
            for (int index = varInfo.type.getArraySize() - 1; index >= 0; --index)
            {
                TIntermBinary *assign = new TIntermBinary(EOpAssign);
                sequence->insert(sequence->begin(), assign);

                TIntermBinary *indexDirect = new TIntermBinary(EOpIndexDirect);
                TIntermSymbol *symbol = new TIntermSymbol(0, varInfo.name, varInfo.type);
                indexDirect->setLeft(symbol);
                TIntermConstantUnion *indexNode = constructIndexNode(index);
                indexDirect->setRight(indexNode);

                assign->setLeft(indexDirect);

                TIntermConstantUnion *zeroConst = constructFloatConstUnionNode(varInfo.type);
                assign->setRight(zeroConst);
            }
        }
        else
        {
            TIntermBinary *assign = new TIntermBinary(EOpAssign);
            sequence->insert(sequence->begin(), assign);
            TIntermSymbol *symbol = new TIntermSymbol(0, varInfo.name, varInfo.type);
            assign->setLeft(symbol);
            TIntermConstantUnion *zeroConst = constructFloatConstUnionNode(varInfo.type);
            assign->setRight(zeroConst);
        }

    }
}

//
// Connect two nodes with a new parent that does a binary operation on the nodes.
//
// Returns the added node.
//
TIntermTyped *TIntermediate::addBinaryMath(
    TOperator op, TIntermTyped *left, TIntermTyped *right, const TSourceLoc &line)
{
    //
    // Need a new node holding things together then.  Make
    // one and promote it to the right type.
    //
    TIntermBinary *node = new TIntermBinary(op);
    node->setLine(line);

    node->setLeft(left);
    node->setRight(right);
    if (!node->promote(mInfoSink))
        return NULL;

    // See if we can fold constants.
    TIntermTyped *foldedNode = node->fold(mInfoSink);
    if (foldedNode)
        return foldedNode;

    return node;
}