//
// Copyright (c) 2002-2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#include "compiler/translator/ParseContext.h"

#include <stdarg.h>
#include <stdio.h>

#include "compiler/preprocessor/SourceLocation.h"
#include "compiler/translator/Cache.h"
#include "compiler/translator/glslang.h"
#include "compiler/translator/ValidateSwitch.h"
#include "compiler/translator/ValidateGlobalInitializer.h"
#include "compiler/translator/util.h"

///////////////////////////////////////////////////////////////////////
//
// Sub- vector and matrix fields
//
////////////////////////////////////////////////////////////////////////

//
// Look at a '.' field selector string and change it into offsets
// for a vector.
//
bool TParseContext::parseVectorFields(const TString &compString,
                                      int vecSize,
                                      TVectorFields &fields,
                                      const TSourceLoc &line)
{
    fields.num = (int)compString.size();
    if (fields.num > 4)
    {
        error(line, "illegal vector field selection", compString.c_str());
        return false;
    }

    enum
    {
        exyzw,
        ergba,
        estpq
    } fieldSet[4];

    for (int i = 0; i < fields.num; ++i)
    {
        switch (compString[i])
        {
            case 'x':
                fields.offsets[i] = 0;
                fieldSet[i]       = exyzw;
                break;
            case 'r':
                fields.offsets[i] = 0;
                fieldSet[i]       = ergba;
                break;
            case 's':
                fields.offsets[i] = 0;
                fieldSet[i]       = estpq;
                break;
            case 'y':
                fields.offsets[i] = 1;
                fieldSet[i]       = exyzw;
                break;
            case 'g':
                fields.offsets[i] = 1;
                fieldSet[i]       = ergba;
                break;
            case 't':
                fields.offsets[i] = 1;
                fieldSet[i]       = estpq;
                break;
            case 'z':
                fields.offsets[i] = 2;
                fieldSet[i]       = exyzw;
                break;
            case 'b':
                fields.offsets[i] = 2;
                fieldSet[i]       = ergba;
                break;
            case 'p':
                fields.offsets[i] = 2;
                fieldSet[i]       = estpq;
                break;

            case 'w':
                fields.offsets[i] = 3;
                fieldSet[i]       = exyzw;
                break;
            case 'a':
                fields.offsets[i] = 3;
                fieldSet[i]       = ergba;
                break;
            case 'q':
                fields.offsets[i] = 3;
                fieldSet[i]       = estpq;
                break;
            default:
                error(line, "illegal vector field selection", compString.c_str());
                return false;
        }
    }

    for (int i = 0; i < fields.num; ++i)
    {
        if (fields.offsets[i] >= vecSize)
        {
            error(line, "vector field selection out of range", compString.c_str());
            return false;
        }

        if (i > 0)
        {
            if (fieldSet[i] != fieldSet[i - 1])
            {
                error(line, "illegal - vector component fields not from the same set",
                      compString.c_str());
                return false;
            }
        }
    }

    return true;
}

///////////////////////////////////////////////////////////////////////
//
// Errors
//
////////////////////////////////////////////////////////////////////////

//
// Track whether errors have occurred.
//
void TParseContext::recover()
{
}

//
// Used by flex/bison to output all syntax and parsing errors.
//
void TParseContext::error(const TSourceLoc &loc,
                          const char *reason,
                          const char *token,
                          const char *extraInfo)
{
    pp::SourceLocation srcLoc;
    srcLoc.file = loc.first_file;
    srcLoc.line = loc.first_line;
    mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, srcLoc, reason, token, extraInfo);
}

void TParseContext::warning(const TSourceLoc &loc,
                            const char *reason,
                            const char *token,
                            const char *extraInfo)
{
    pp::SourceLocation srcLoc;
    srcLoc.file = loc.first_file;
    srcLoc.line = loc.first_line;
    mDiagnostics.writeInfo(pp::Diagnostics::PP_WARNING, srcLoc, reason, token, extraInfo);
}

void TParseContext::outOfRangeError(bool isError,
                                    const TSourceLoc &loc,
                                    const char *reason,
                                    const char *token,
                                    const char *extraInfo)
{
    if (isError)
    {
        error(loc, reason, token, extraInfo);
        recover();
    }
    else
    {
        warning(loc, reason, token, extraInfo);
    }
}

//
// Same error message for all places assignments don't work.
//
void TParseContext::assignError(const TSourceLoc &line, const char *op, TString left, TString right)
{
    std::stringstream extraInfoStream;
    extraInfoStream << "cannot convert from '" << right << "' to '" << left << "'";
    std::string extraInfo = extraInfoStream.str();
    error(line, "", op, extraInfo.c_str());
}

//
// Same error message for all places unary operations don't work.
//
void TParseContext::unaryOpError(const TSourceLoc &line, const char *op, TString operand)
{
    std::stringstream extraInfoStream;
    extraInfoStream << "no operation '" << op << "' exists that takes an operand of type "
                    << operand << " (or there is no acceptable conversion)";
    std::string extraInfo = extraInfoStream.str();
    error(line, " wrong operand type", op, extraInfo.c_str());
}

//
// Same error message for all binary operations don't work.
//
void TParseContext::binaryOpError(const TSourceLoc &line,
                                  const char *op,
                                  TString left,
                                  TString right)
{
    std::stringstream extraInfoStream;
    extraInfoStream << "no operation '" << op << "' exists that takes a left-hand operand of type '"
                    << left << "' and a right operand of type '" << right
                    << "' (or there is no acceptable conversion)";
    std::string extraInfo = extraInfoStream.str();
    error(line, " wrong operand types ", op, extraInfo.c_str());
}

bool TParseContext::precisionErrorCheck(const TSourceLoc &line,
                                        TPrecision precision,
                                        TBasicType type)
{
    if (!mChecksPrecisionErrors)
        return false;
    if (precision == EbpUndefined)
    {
        switch (type)
        {
            case EbtFloat:
                error(line, "No precision specified for (float)", "");
                return true;
            case EbtInt:
            case EbtUInt:
                UNREACHABLE();  // there's always a predeclared qualifier
                error(line, "No precision specified (int)", "");
                return true;
            default:
                if (IsSampler(type))
                {
                    error(line, "No precision specified (sampler)", "");
                    return true;
                }
        }
    }
    return false;
}

//
// Both test and if necessary, spit out an error, to see if the node is really
// an l-value that can be operated on this way.
//
// Returns true if the was an error.
//
bool TParseContext::lValueErrorCheck(const TSourceLoc &line, const char *op, TIntermTyped *node)
{
    TIntermSymbol *symNode    = node->getAsSymbolNode();
    TIntermBinary *binaryNode = node->getAsBinaryNode();

    if (binaryNode)
    {
        bool errorReturn;

        switch (binaryNode->getOp())
        {
            case EOpIndexDirect:
            case EOpIndexIndirect:
            case EOpIndexDirectStruct:
            case EOpIndexDirectInterfaceBlock:
                return lValueErrorCheck(line, op, binaryNode->getLeft());
            case EOpVectorSwizzle:
                errorReturn = lValueErrorCheck(line, op, binaryNode->getLeft());
                if (!errorReturn)
                {
                    int offset[4] = {0, 0, 0, 0};

                    TIntermTyped *rightNode    = binaryNode->getRight();
                    TIntermAggregate *aggrNode = rightNode->getAsAggregate();

                    for (TIntermSequence::iterator p = aggrNode->getSequence()->begin();
                         p != aggrNode->getSequence()->end(); p++)
                    {
                        int value = (*p)->getAsTyped()->getAsConstantUnion()->getIConst(0);
                        offset[value]++;
                        if (offset[value] > 1)
                        {
                            error(line, " l-value of swizzle cannot have duplicate components", op);

                            return true;
                        }
                    }
                }

                return errorReturn;
            default:
                break;
        }
        error(line, " l-value required", op);

        return true;
    }

    const char *symbol = 0;
    if (symNode != 0)
        symbol = symNode->getSymbol().c_str();

    const char *message = 0;
    switch (node->getQualifier())
    {
        case EvqConst:
            message = "can't modify a const";
            break;
        case EvqConstReadOnly:
            message = "can't modify a const";
            break;
        case EvqAttribute:
            message = "can't modify an attribute";
            break;
        case EvqFragmentIn:
            message = "can't modify an input";
            break;
        case EvqVertexIn:
            message = "can't modify an input";
            break;
        case EvqUniform:
            message = "can't modify a uniform";
            break;
        case EvqVaryingIn:
            message = "can't modify a varying";
            break;
        case EvqFragCoord:
            message = "can't modify gl_FragCoord";
            break;
        case EvqFrontFacing:
            message = "can't modify gl_FrontFacing";
            break;
        case EvqPointCoord:
            message = "can't modify gl_PointCoord";
            break;
        default:
            //
            // Type that can't be written to?
            //
            if (node->getBasicType() == EbtVoid)
            {
                message = "can't modify void";
            }
            if (IsSampler(node->getBasicType()))
            {
                message = "can't modify a sampler";
            }
    }

    if (message == 0 && binaryNode == 0 && symNode == 0)
    {
        error(line, " l-value required", op);

        return true;
    }

    //
    // Everything else is okay, no error.
    //
    if (message == 0)
        return false;

    //
    // If we get here, we have an error and a message.
    //
    if (symNode)
    {
        std::stringstream extraInfoStream;
        extraInfoStream << "\"" << symbol << "\" (" << message << ")";
        std::string extraInfo = extraInfoStream.str();
        error(line, " l-value required", op, extraInfo.c_str());
    }
    else
    {
        std::stringstream extraInfoStream;
        extraInfoStream << "(" << message << ")";
        std::string extraInfo = extraInfoStream.str();
        error(line, " l-value required", op, extraInfo.c_str());
    }

    return true;
}

//
// Both test, and if necessary spit out an error, to see if the node is really
// a constant.
//
// Returns true if the was an error.
//
bool TParseContext::constErrorCheck(TIntermTyped *node)
{
    if (node->getQualifier() == EvqConst)
        return false;

    error(node->getLine(), "constant expression required", "");

    return true;
}

//
// Both test, and if necessary spit out an error, to see if the node is really
// an integer.
//
// Returns true if the was an error.
//
bool TParseContext::integerErrorCheck(TIntermTyped *node, const char *token)
{
    if (node->isScalarInt())
        return false;

    error(node->getLine(), "integer expression required", token);

    return true;
}

//
// Both test, and if necessary spit out an error, to see if we are currently
// globally scoped.
//
// Returns true if the was an error.
//
bool TParseContext::globalErrorCheck(const TSourceLoc &line, bool global, const char *token)
{
    if (global)
        return false;

    error(line, "only allowed at global scope", token);

    return true;
}

//
// For now, keep it simple:  if it starts "gl_", it's reserved, independent
// of scope.  Except, if the symbol table is at the built-in push-level,
// which is when we are parsing built-ins.
// Also checks for "webgl_" and "_webgl_" reserved identifiers if parsing a
// webgl shader.
//
// Returns true if there was an error.
//
bool TParseContext::reservedErrorCheck(const TSourceLoc &line, const TString &identifier)
{
    static const char *reservedErrMsg = "reserved built-in name";
    if (!symbolTable.atBuiltInLevel())
    {
        if (identifier.compare(0, 3, "gl_") == 0)
        {
            error(line, reservedErrMsg, "gl_");
            return true;
        }
        if (IsWebGLBasedSpec(mShaderSpec))
        {
            if (identifier.compare(0, 6, "webgl_") == 0)
            {
                error(line, reservedErrMsg, "webgl_");
                return true;
            }
            if (identifier.compare(0, 7, "_webgl_") == 0)
            {
                error(line, reservedErrMsg, "_webgl_");
                return true;
            }
            if (mShaderSpec == SH_CSS_SHADERS_SPEC && identifier.compare(0, 4, "css_") == 0)
            {
                error(line, reservedErrMsg, "css_");
                return true;
            }
        }
        if (identifier.find("__") != TString::npos)
        {
            error(line,
                  "identifiers containing two consecutive underscores (__) are reserved as "
                  "possible future keywords",
                  identifier.c_str());
            return true;
        }
    }

    return false;
}

//
// Make sure there is enough data provided to the constructor to build
// something of the type of the constructor.  Also returns the type of
// the constructor.
//
// Returns true if there was an error in construction.
//
bool TParseContext::constructorErrorCheck(const TSourceLoc &line,
                                          TIntermNode *argumentsNode,
                                          TFunction &function,
                                          TOperator op,
                                          TType *type)
{
    *type = function.getReturnType();

    bool constructingMatrix = false;
    switch (op)
    {
        case EOpConstructMat2:
        case EOpConstructMat2x3:
        case EOpConstructMat2x4:
        case EOpConstructMat3x2:
        case EOpConstructMat3:
        case EOpConstructMat3x4:
        case EOpConstructMat4x2:
        case EOpConstructMat4x3:
        case EOpConstructMat4:
            constructingMatrix = true;
            break;
        default:
            break;
    }

    //
    // Note: It's okay to have too many components available, but not okay to have unused
    // arguments.  'full' will go to true when enough args have been seen.  If we loop
    // again, there is an extra argument, so 'overfull' will become true.
    //

    size_t size         = 0;
    bool constType      = true;
    bool full           = false;
    bool overFull       = false;
    bool matrixInMatrix = false;
    bool arrayArg = false;
    for (size_t i = 0; i < function.getParamCount(); ++i)
    {
        const TConstParameter &param = function.getParam(i);
        size += param.type->getObjectSize();

        if (constructingMatrix && param.type->isMatrix())
            matrixInMatrix = true;
        if (full)
            overFull = true;
        if (op != EOpConstructStruct && !type->isArray() && size >= type->getObjectSize())
            full = true;
        if (param.type->getQualifier() != EvqConst)
            constType = false;
        if (param.type->isArray())
            arrayArg = true;
    }

    if (constType)
        type->setQualifier(EvqConst);

    if (type->isArray())
    {
        if (type->isUnsizedArray())
        {
            type->setArraySize(static_cast<int>(function.getParamCount()));
        }
        else if (static_cast<size_t>(type->getArraySize()) != function.getParamCount())
        {
            error(line, "array constructor needs one argument per array element", "constructor");
            return true;
        }
    }

    if (arrayArg && op != EOpConstructStruct)
    {
        error(line, "constructing from a non-dereferenced array", "constructor");
        return true;
    }

    if (matrixInMatrix && !type->isArray())
    {
        if (function.getParamCount() != 1)
        {
            error(line, "constructing matrix from matrix can only take one argument",
                  "constructor");
            return true;
        }
    }

    if (overFull)
    {
        error(line, "too many arguments", "constructor");
        return true;
    }

    if (op == EOpConstructStruct && !type->isArray() &&
        type->getStruct()->fields().size() != function.getParamCount())
    {
        error(line,
              "Number of constructor parameters does not match the number of structure fields",
              "constructor");
        return true;
    }

    if (!type->isMatrix() || !matrixInMatrix)
    {
        if ((op != EOpConstructStruct && size != 1 && size < type->getObjectSize()) ||
            (op == EOpConstructStruct && size < type->getObjectSize()))
        {
            error(line, "not enough data provided for construction", "constructor");
            return true;
        }
    }

    if (argumentsNode == nullptr)
    {
        error(line, "constructor does not have any arguments", "constructor");
        return true;
    }

    TIntermAggregate *argumentsAgg = argumentsNode->getAsAggregate();
    for (TIntermNode *&argNode : *argumentsAgg->getSequence())
    {
        TIntermTyped *argTyped = argNode->getAsTyped();
        ASSERT(argTyped != nullptr);
        if (op != EOpConstructStruct && IsSampler(argTyped->getBasicType()))
        {
            error(line, "cannot convert a sampler", "constructor");
            return true;
        }
        if (argTyped->getBasicType() == EbtVoid)
        {
            error(line, "cannot convert a void", "constructor");
            return true;
        }
    }

    return false;
}

// This function checks to see if a void variable has been declared and raise an error message for
// such a case
//
// returns true in case of an error
//
bool TParseContext::voidErrorCheck(const TSourceLoc &line,
                                   const TString &identifier,
                                   const TBasicType &type)
{
    if (type == EbtVoid)
    {
        error(line, "illegal use of type 'void'", identifier.c_str());
        return true;
    }

    return false;
}

// This function checks to see if the node (for the expression) contains a scalar boolean expression
// or not
//
// returns true in case of an error
//
bool TParseContext::boolErrorCheck(const TSourceLoc &line, const TIntermTyped *type)
{
    if (type->getBasicType() != EbtBool || type->isArray() || type->isMatrix() || type->isVector())
    {
        error(line, "boolean expression expected", "");
        return true;
    }

    return false;
}

// This function checks to see if the node (for the expression) contains a scalar boolean expression
// or not
//
// returns true in case of an error
//
bool TParseContext::boolErrorCheck(const TSourceLoc &line, const TPublicType &pType)
{
    if (pType.type != EbtBool || pType.isAggregate())
    {
        error(line, "boolean expression expected", "");
        return true;
    }

    return false;
}

bool TParseContext::samplerErrorCheck(const TSourceLoc &line,
                                      const TPublicType &pType,
                                      const char *reason)
{
    if (pType.type == EbtStruct)
    {
        if (containsSampler(*pType.userDef))
        {
            error(line, reason, getBasicString(pType.type), "(structure contains a sampler)");

            return true;
        }

        return false;
    }
    else if (IsSampler(pType.type))
    {
        error(line, reason, getBasicString(pType.type));

        return true;
    }

    return false;
}

bool TParseContext::locationDeclaratorListCheck(const TSourceLoc &line, const TPublicType &pType)
{
    if (pType.layoutQualifier.location != -1)
    {
        error(line, "location must only be specified for a single input or output variable",
              "location");
        return true;
    }

    return false;
}

bool TParseContext::parameterSamplerErrorCheck(const TSourceLoc &line,
                                               TQualifier qualifier,
                                               const TType &type)
{
    if ((qualifier == EvqOut || qualifier == EvqInOut) && type.getBasicType() != EbtStruct &&
        IsSampler(type.getBasicType()))
    {
        error(line, "samplers cannot be output parameters", type.getBasicString());
        return true;
    }

    return false;
}

bool TParseContext::containsSampler(const TType &type)
{
    if (IsSampler(type.getBasicType()))
        return true;

    if (type.getBasicType() == EbtStruct || type.isInterfaceBlock())
    {
        const TFieldList &fields = type.getStruct()->fields();
        for (unsigned int i = 0; i < fields.size(); ++i)
        {
            if (containsSampler(*fields[i]->type()))
                return true;
        }
    }

    return false;
}

//
// Do size checking for an array type's size.
//
// Returns true if there was an error.
//
bool TParseContext::arraySizeErrorCheck(const TSourceLoc &line, TIntermTyped *expr, int &size)
{
    TIntermConstantUnion *constant = expr->getAsConstantUnion();

    // TODO(oetuaho@nvidia.com): Get rid of the constant == nullptr check here once all constant
    // expressions can be folded. Right now we don't allow constant expressions that ANGLE can't
    // fold as array size.
    if (expr->getQualifier() != EvqConst || constant == nullptr || !constant->isScalarInt())
    {
        error(line, "array size must be a constant integer expression", "");
        size = 1;
        return true;
    }

    unsigned int unsignedSize = 0;

    if (constant->getBasicType() == EbtUInt)
    {
        unsignedSize = constant->getUConst(0);
        size         = static_cast<int>(unsignedSize);
    }
    else
    {
        size = constant->getIConst(0);

        if (size < 0)
        {
            error(line, "array size must be non-negative", "");
            size = 1;
            return true;
        }

        unsignedSize = static_cast<unsigned int>(size);
    }

    if (size == 0)
    {
        error(line, "array size must be greater than zero", "");
        size = 1;
        return true;
    }

    // The size of arrays is restricted here to prevent issues further down the
    // compiler/translator/driver stack. Shader Model 5 generation hardware is limited to
    // 4096 registers so this should be reasonable even for aggressively optimizable code.
    const unsigned int sizeLimit = 65536;

    if (unsignedSize > sizeLimit)
    {
        error(line, "array size too large", "");
        size = 1;
        return true;
    }

    return false;
}

//
// See if this qualifier can be an array.
//
// Returns true if there is an error.
//
bool TParseContext::arrayQualifierErrorCheck(const TSourceLoc &line, const TPublicType &type)
{
    if ((type.qualifier == EvqAttribute) || (type.qualifier == EvqVertexIn) ||
        (type.qualifier == EvqConst && mShaderVersion < 300))
    {
        error(line, "cannot declare arrays of this qualifier",
              TType(type).getCompleteString().c_str());
        return true;
    }

    return false;
}

//
// See if this type can be an array.
//
// Returns true if there is an error.
//
bool TParseContext::arrayTypeErrorCheck(const TSourceLoc &line, const TPublicType &type)
{
    //
    // Can the type be an array?
    //
    if (type.array)
    {
        error(line, "cannot declare arrays of arrays", TType(type).getCompleteString().c_str());
        return true;
    }
    // In ESSL1.00 shaders, structs cannot be varying (section 4.3.5). This is checked elsewhere.
    // In ESSL3.00 shaders, struct inputs/outputs are allowed but not arrays of structs (section
    // 4.3.4).
    if (mShaderVersion >= 300 && type.type == EbtStruct && sh::IsVarying(type.qualifier))
    {
        error(line, "cannot declare arrays of structs of this qualifier",
              TType(type).getCompleteString().c_str());
        return true;
    }

    return false;
}

//
// Enforce non-initializer type/qualifier rules.
//
// Returns true if there was an error.
//
bool TParseContext::nonInitErrorCheck(const TSourceLoc &line,
                                      const TString &identifier,
                                      TPublicType *type)
{
    ASSERT(type != nullptr);
    if (type->qualifier == EvqConst)
    {
        // Make the qualifier make sense.
        type->qualifier = EvqTemporary;

        // Generate informative error messages for ESSL1.
        // In ESSL3 arrays and structures containing arrays can be constant.
        if (mShaderVersion < 300 && type->isStructureContainingArrays())
        {
            error(line,
                  "structures containing arrays may not be declared constant since they cannot be "
                  "initialized",
                  identifier.c_str());
        }
        else
        {
            error(line, "variables with qualifier 'const' must be initialized", identifier.c_str());
        }

        return true;
    }
    if (type->isUnsizedArray())
    {
        error(line, "implicitly sized arrays need to be initialized", identifier.c_str());
        return true;
    }
    return false;
}

// Do some simple checks that are shared between all variable declarations,
// and update the symbol table.
//
// Returns true if declaring the variable succeeded.
//
bool TParseContext::declareVariable(const TSourceLoc &line,
                                    const TString &identifier,
                                    const TType &type,
                                    TVariable **variable)
{
    ASSERT((*variable) == nullptr);

    bool needsReservedErrorCheck = true;

    // gl_LastFragData may be redeclared with a new precision qualifier
    if (type.isArray() && identifier.compare(0, 15, "gl_LastFragData") == 0)
    {
        const TVariable *maxDrawBuffers = static_cast<const TVariable *>(
            symbolTable.findBuiltIn("gl_MaxDrawBuffers", mShaderVersion));
        if (type.getArraySize() == maxDrawBuffers->getConstPointer()->getIConst())
        {
            if (TSymbol *builtInSymbol = symbolTable.findBuiltIn(identifier, mShaderVersion))
            {
                needsReservedErrorCheck = extensionErrorCheck(line, builtInSymbol->getExtension());
            }
        }
        else
        {
            error(line, "redeclaration of gl_LastFragData with size != gl_MaxDrawBuffers",
                  identifier.c_str());
            return false;
        }
    }

    if (needsReservedErrorCheck && reservedErrorCheck(line, identifier))
        return false;

    (*variable) = new TVariable(&identifier, type);
    if (!symbolTable.declare(*variable))
    {
        error(line, "redefinition", identifier.c_str());
        *variable = nullptr;
        return false;
    }

    if (voidErrorCheck(line, identifier, type.getBasicType()))
        return false;

    return true;
}

bool TParseContext::paramErrorCheck(const TSourceLoc &line,
                                    TQualifier qualifier,
                                    TQualifier paramQualifier,
                                    TType *type)
{
    if (qualifier != EvqConst && qualifier != EvqTemporary)
    {
        error(line, "qualifier not allowed on function parameter", getQualifierString(qualifier));
        return true;
    }
    if (qualifier == EvqConst && paramQualifier != EvqIn)
    {
        error(line, "qualifier not allowed with ", getQualifierString(qualifier),
              getQualifierString(paramQualifier));
        return true;
    }

    if (qualifier == EvqConst)
        type->setQualifier(EvqConstReadOnly);
    else
        type->setQualifier(paramQualifier);

    return false;
}

bool TParseContext::extensionErrorCheck(const TSourceLoc &line, const TString &extension)
{
    const TExtensionBehavior &extBehavior   = extensionBehavior();
    TExtensionBehavior::const_iterator iter = extBehavior.find(extension.c_str());
    if (iter == extBehavior.end())
    {
        error(line, "extension", extension.c_str(), "is not supported");
        return true;
    }
    // In GLSL ES, an extension's default behavior is "disable".
    if (iter->second == EBhDisable || iter->second == EBhUndefined)
    {
        error(line, "extension", extension.c_str(), "is disabled");
        return true;
    }
    if (iter->second == EBhWarn)
    {
        warning(line, "extension", extension.c_str(), "is being used");
        return false;
    }

    return false;
}

// These checks are common for all declarations starting a declarator list, and declarators that
// follow an empty declaration.
//
bool TParseContext::singleDeclarationErrorCheck(const TPublicType &publicType,
                                                const TSourceLoc &identifierLocation)
{
    switch (publicType.qualifier)
    {
        case EvqVaryingIn:
        case EvqVaryingOut:
        case EvqAttribute:
        case EvqVertexIn:
        case EvqFragmentOut:
            if (publicType.type == EbtStruct)
            {
                error(identifierLocation, "cannot be used with a structure",
                      getQualifierString(publicType.qualifier));
                return true;
            }

        default:
            break;
    }

    if (publicType.qualifier != EvqUniform &&
        samplerErrorCheck(identifierLocation, publicType, "samplers must be uniform"))
    {
        return true;
    }

    // check for layout qualifier issues
    const TLayoutQualifier layoutQualifier = publicType.layoutQualifier;

    if (layoutQualifier.matrixPacking != EmpUnspecified)
    {
        error(identifierLocation, "layout qualifier",
              getMatrixPackingString(layoutQualifier.matrixPacking),
              "only valid for interface blocks");
        return true;
    }

    if (layoutQualifier.blockStorage != EbsUnspecified)
    {
        error(identifierLocation, "layout qualifier",
              getBlockStorageString(layoutQualifier.blockStorage),
              "only valid for interface blocks");
        return true;
    }

    if (publicType.qualifier != EvqVertexIn && publicType.qualifier != EvqFragmentOut &&
        layoutLocationErrorCheck(identifierLocation, publicType.layoutQualifier))
    {
        return true;
    }

    return false;
}

bool TParseContext::layoutLocationErrorCheck(const TSourceLoc &location,
                                             const TLayoutQualifier &layoutQualifier)
{
    if (layoutQualifier.location != -1)
    {
        error(location, "invalid layout qualifier:", "location",
              "only valid on program inputs and outputs");
        return true;
    }

    return false;
}

bool TParseContext::functionCallLValueErrorCheck(const TFunction *fnCandidate,
                                                 TIntermAggregate *aggregate)
{
    for (size_t i = 0; i < fnCandidate->getParamCount(); ++i)
    {
        TQualifier qual = fnCandidate->getParam(i).type->getQualifier();
        if (qual == EvqOut || qual == EvqInOut)
        {
            TIntermTyped *node = (*(aggregate->getSequence()))[i]->getAsTyped();
            if (lValueErrorCheck(node->getLine(), "assign", node))
            {
                error(node->getLine(),
                      "Constant value cannot be passed for 'out' or 'inout' parameters.", "Error");
                recover();
                return true;
            }
        }
    }
    return false;
}

void TParseContext::es3InvariantErrorCheck(const TQualifier qualifier,
                                           const TSourceLoc &invariantLocation)
{
    if (!sh::IsVaryingOut(qualifier) && qualifier != EvqFragmentOut)
    {
        error(invariantLocation, "Only out variables can be invariant.", "invariant");
        recover();
    }
}

bool TParseContext::supportsExtension(const char *extension)
{
    const TExtensionBehavior &extbehavior   = extensionBehavior();
    TExtensionBehavior::const_iterator iter = extbehavior.find(extension);
    return (iter != extbehavior.end());
}

bool TParseContext::isExtensionEnabled(const char *extension) const
{
    return ::IsExtensionEnabled(extensionBehavior(), extension);
}

void TParseContext::handleExtensionDirective(const TSourceLoc &loc,
                                             const char *extName,
                                             const char *behavior)
{
    pp::SourceLocation srcLoc;
    srcLoc.file = loc.first_file;
    srcLoc.line = loc.first_line;
    mDirectiveHandler.handleExtension(srcLoc, extName, behavior);
}

void TParseContext::handlePragmaDirective(const TSourceLoc &loc,
                                          const char *name,
                                          const char *value,
                                          bool stdgl)
{
    pp::SourceLocation srcLoc;
    srcLoc.file = loc.first_file;
    srcLoc.line = loc.first_line;
    mDirectiveHandler.handlePragma(srcLoc, name, value, stdgl);
}

/////////////////////////////////////////////////////////////////////////////////
//
// Non-Errors.
//
/////////////////////////////////////////////////////////////////////////////////

const TVariable *TParseContext::getNamedVariable(const TSourceLoc &location,
                                                 const TString *name,
                                                 const TSymbol *symbol)
{
    const TVariable *variable = NULL;

    if (!symbol)
    {
        error(location, "undeclared identifier", name->c_str());
        recover();
    }
    else if (!symbol->isVariable())
    {
        error(location, "variable expected", name->c_str());
        recover();
    }
    else
    {
        variable = static_cast<const TVariable *>(symbol);

        if (symbolTable.findBuiltIn(variable->getName(), mShaderVersion) &&
            !variable->getExtension().empty() &&
            extensionErrorCheck(location, variable->getExtension()))
        {
            recover();
        }

        // Reject shaders using both gl_FragData and gl_FragColor
        TQualifier qualifier = variable->getType().getQualifier();
        if (qualifier == EvqFragData || qualifier == EvqSecondaryFragDataEXT)
        {
            mUsesFragData = true;
        }
        else if (qualifier == EvqFragColor || qualifier == EvqSecondaryFragColorEXT)
        {
            mUsesFragColor = true;
        }
        if (qualifier == EvqSecondaryFragDataEXT || qualifier == EvqSecondaryFragColorEXT)
        {
            mUsesSecondaryOutputs = true;
        }

        // This validation is not quite correct - it's only an error to write to
        // both FragData and FragColor. For simplicity, and because users shouldn't
        // be rewarded for reading from undefined varaibles, return an error
        // if they are both referenced, rather than assigned.
        if (mUsesFragData && mUsesFragColor)
        {
            const char *errorMessage = "cannot use both gl_FragData and gl_FragColor";
            if (mUsesSecondaryOutputs)
            {
                errorMessage =
                    "cannot use both output variable sets (gl_FragData, gl_SecondaryFragDataEXT)"
                    " and (gl_FragColor, gl_SecondaryFragColorEXT)";
            }
            error(location, errorMessage, name->c_str());
            recover();
        }
    }

    if (!variable)
    {
        TType type(EbtFloat, EbpUndefined);
        TVariable *fakeVariable = new TVariable(name, type);
        symbolTable.declare(fakeVariable);
        variable = fakeVariable;
    }

    return variable;
}

TIntermTyped *TParseContext::parseVariableIdentifier(const TSourceLoc &location,
                                                     const TString *name,
                                                     const TSymbol *symbol)
{
    const TVariable *variable = getNamedVariable(location, name, symbol);

    if (variable->getConstPointer())
    {
        const TConstantUnion *constArray = variable->getConstPointer();
        return intermediate.addConstantUnion(constArray, variable->getType(), location);
    }
    else
    {
        return intermediate.addSymbol(variable->getUniqueId(), variable->getName(),
                                      variable->getType(), location);
    }
}

//
// Look up a function name in the symbol table, and make sure it is a function.
//
// Return the function symbol if found, otherwise 0.
//
const TFunction *TParseContext::findFunction(const TSourceLoc &line,
                                             TFunction *call,
                                             int inputShaderVersion,
                                             bool *builtIn)
{
    // First find by unmangled name to check whether the function name has been
    // hidden by a variable name or struct typename.
    // If a function is found, check for one with a matching argument list.
    const TSymbol *symbol = symbolTable.find(call->getName(), inputShaderVersion, builtIn);
    if (symbol == 0 || symbol->isFunction())
    {
        symbol = symbolTable.find(call->getMangledName(), inputShaderVersion, builtIn);
    }

    if (symbol == 0)
    {
        error(line, "no matching overloaded function found", call->getName().c_str());
        return 0;
    }

    if (!symbol->isFunction())
    {
        error(line, "function name expected", call->getName().c_str());
        return 0;
    }

    return static_cast<const TFunction *>(symbol);
}

//
// Initializers show up in several places in the grammar.  Have one set of
// code to handle them here.
//
// Returns true on error, false if no error
//
bool TParseContext::executeInitializer(const TSourceLoc &line,
                                       const TString &identifier,
                                       const TPublicType &pType,
                                       TIntermTyped *initializer,
                                       TIntermNode **intermNode)
{
    ASSERT(intermNode != nullptr);
    TType type = TType(pType);

    TVariable *variable = nullptr;
    if (type.isUnsizedArray())
    {
        type.setArraySize(initializer->getArraySize());
    }
    if (!declareVariable(line, identifier, type, &variable))
    {
        return true;
    }

    bool globalInitWarning = false;
    if (symbolTable.atGlobalLevel() &&
        !ValidateGlobalInitializer(initializer, this, &globalInitWarning))
    {
        // Error message does not completely match behavior with ESSL 1.00, but
        // we want to steer developers towards only using constant expressions.
        error(line, "global variable initializers must be constant expressions", "=");
        return true;
    }
    if (globalInitWarning)
    {
        warning(
            line,
            "global variable initializers should be constant expressions "
            "(uniforms and globals are allowed in global initializers for legacy compatibility)",
            "=");
    }

    //
    // identifier must be of type constant, a global, or a temporary
    //
    TQualifier qualifier = variable->getType().getQualifier();
    if ((qualifier != EvqTemporary) && (qualifier != EvqGlobal) && (qualifier != EvqConst))
    {
        error(line, " cannot initialize this type of qualifier ",
              variable->getType().getQualifierString());
        return true;
    }
    //
    // test for and propagate constant
    //

    if (qualifier == EvqConst)
    {
        if (qualifier != initializer->getType().getQualifier())
        {
            std::stringstream extraInfoStream;
            extraInfoStream << "'" << variable->getType().getCompleteString() << "'";
            std::string extraInfo = extraInfoStream.str();
            error(line, " assigning non-constant to", "=", extraInfo.c_str());
            variable->getType().setQualifier(EvqTemporary);
            return true;
        }
        if (type != initializer->getType())
        {
            error(line, " non-matching types for const initializer ",
                  variable->getType().getQualifierString());
            variable->getType().setQualifier(EvqTemporary);
            return true;
        }

        // Save the constant folded value to the variable if possible. For example array
        // initializers are not folded, since that way copying the array literal to multiple places
        // in the shader is avoided.
        // TODO(oetuaho@nvidia.com): Consider constant folding array initialization in cases where
        // it would be beneficial.
        if (initializer->getAsConstantUnion())
        {
            variable->shareConstPointer(initializer->getAsConstantUnion()->getUnionArrayPointer());
            *intermNode = nullptr;
            return false;
        }
        else if (initializer->getAsSymbolNode())
        {
            const TSymbol *symbol =
                symbolTable.find(initializer->getAsSymbolNode()->getSymbol(), 0);
            const TVariable *tVar = static_cast<const TVariable *>(symbol);

            const TConstantUnion *constArray = tVar->getConstPointer();
            if (constArray)
            {
                variable->shareConstPointer(constArray);
                *intermNode = nullptr;
                return false;
            }
        }
    }

    TIntermSymbol *intermSymbol = intermediate.addSymbol(
        variable->getUniqueId(), variable->getName(), variable->getType(), line);
    *intermNode = createAssign(EOpInitialize, intermSymbol, initializer, line);
    if (*intermNode == nullptr)
    {
        assignError(line, "=", intermSymbol->getCompleteString(), initializer->getCompleteString());
        return true;
    }

    return false;
}

TPublicType TParseContext::addFullySpecifiedType(TQualifier qualifier,
                                                 bool invariant,
                                                 TLayoutQualifier layoutQualifier,
                                                 const TPublicType &typeSpecifier)
{
    TPublicType returnType     = typeSpecifier;
    returnType.qualifier       = qualifier;
    returnType.invariant       = invariant;
    returnType.layoutQualifier = layoutQualifier;

    if (mShaderVersion < 300)
    {
        if (typeSpecifier.array)
        {
            error(typeSpecifier.line, "not supported", "first-class array");
            recover();
            returnType.clearArrayness();
        }

        if (qualifier == EvqAttribute &&
            (typeSpecifier.type == EbtBool || typeSpecifier.type == EbtInt))
        {
            error(typeSpecifier.line, "cannot be bool or int", getQualifierString(qualifier));
            recover();
        }

        if ((qualifier == EvqVaryingIn || qualifier == EvqVaryingOut) &&
            (typeSpecifier.type == EbtBool || typeSpecifier.type == EbtInt))
        {
            error(typeSpecifier.line, "cannot be bool or int", getQualifierString(qualifier));
            recover();
        }
    }
    else
    {
        if (!layoutQualifier.isEmpty())
        {
            if (globalErrorCheck(typeSpecifier.line, symbolTable.atGlobalLevel(), "layout"))
            {
                recover();
            }
        }
        if (sh::IsVarying(qualifier) || qualifier == EvqVertexIn || qualifier == EvqFragmentOut)
        {
            es3InputOutputTypeCheck(qualifier, typeSpecifier, typeSpecifier.line);
        }
    }

    return returnType;
}

void TParseContext::es3InputOutputTypeCheck(const TQualifier qualifier,
                                            const TPublicType &type,
                                            const TSourceLoc &qualifierLocation)
{
    // An input/output variable can never be bool or a sampler. Samplers are checked elsewhere.
    if (type.type == EbtBool)
    {
        error(qualifierLocation, "cannot be bool", getQualifierString(qualifier));
        recover();
    }

    // Specific restrictions apply for vertex shader inputs and fragment shader outputs.
    switch (qualifier)
    {
        case EvqVertexIn:
            // ESSL 3.00 section 4.3.4
            if (type.array)
            {
                error(qualifierLocation, "cannot be array", getQualifierString(qualifier));
                recover();
            }
            // Vertex inputs with a struct type are disallowed in singleDeclarationErrorCheck
            return;
        case EvqFragmentOut:
            // ESSL 3.00 section 4.3.6
            if (type.isMatrix())
            {
                error(qualifierLocation, "cannot be matrix", getQualifierString(qualifier));
                recover();
            }
            // Fragment outputs with a struct type are disallowed in singleDeclarationErrorCheck
            return;
        default:
            break;
    }

    // Vertex shader outputs / fragment shader inputs have a different, slightly more lenient set of
    // restrictions.
    bool typeContainsIntegers =
        (type.type == EbtInt || type.type == EbtUInt || type.isStructureContainingType(EbtInt) ||
         type.isStructureContainingType(EbtUInt));
    if (typeContainsIntegers && qualifier != EvqFlatIn && qualifier != EvqFlatOut)
    {
        error(qualifierLocation, "must use 'flat' interpolation here",
              getQualifierString(qualifier));
        recover();
    }

    if (type.type == EbtStruct)
    {
        // ESSL 3.00 sections 4.3.4 and 4.3.6.
        // These restrictions are only implied by the ESSL 3.00 spec, but
        // the ESSL 3.10 spec lists these restrictions explicitly.
        if (type.array)
        {
            error(qualifierLocation, "cannot be an array of structures",
                  getQualifierString(qualifier));
            recover();
        }
        if (type.isStructureContainingArrays())
        {
            error(qualifierLocation, "cannot be a structure containing an array",
                  getQualifierString(qualifier));
            recover();
        }
        if (type.isStructureContainingType(EbtStruct))
        {
            error(qualifierLocation, "cannot be a structure containing a structure",
                  getQualifierString(qualifier));
            recover();
        }
        if (type.isStructureContainingType(EbtBool))
        {
            error(qualifierLocation, "cannot be a structure containing a bool",
                  getQualifierString(qualifier));
            recover();
        }
    }
}

TIntermAggregate *TParseContext::parseSingleDeclaration(TPublicType &publicType,
                                                        const TSourceLoc &identifierOrTypeLocation,
                                                        const TString &identifier)
{
    TIntermSymbol *symbol =
        intermediate.addSymbol(0, identifier, TType(publicType), identifierOrTypeLocation);

    bool emptyDeclaration = (identifier == "");

    mDeferredSingleDeclarationErrorCheck = emptyDeclaration;

    if (emptyDeclaration)
    {
        if (publicType.isUnsizedArray())
        {
            // ESSL3 spec section 4.1.9: Array declaration which leaves the size unspecified is an
            // error. It is assumed that this applies to empty declarations as well.
            error(identifierOrTypeLocation, "empty array declaration needs to specify a size",
                  identifier.c_str());
        }
    }
    else
    {
        if (singleDeclarationErrorCheck(publicType, identifierOrTypeLocation))
            recover();

        if (nonInitErrorCheck(identifierOrTypeLocation, identifier, &publicType))
            recover();

        TVariable *variable = nullptr;
        if (!declareVariable(identifierOrTypeLocation, identifier, TType(publicType), &variable))
            recover();

        if (variable && symbol)
            symbol->setId(variable->getUniqueId());
    }

    return intermediate.makeAggregate(symbol, identifierOrTypeLocation);
}

TIntermAggregate *TParseContext::parseSingleArrayDeclaration(TPublicType &publicType,
                                                             const TSourceLoc &identifierLocation,
                                                             const TString &identifier,
                                                             const TSourceLoc &indexLocation,
                                                             TIntermTyped *indexExpression)
{
    mDeferredSingleDeclarationErrorCheck = false;

    if (singleDeclarationErrorCheck(publicType, identifierLocation))
        recover();

    if (nonInitErrorCheck(identifierLocation, identifier, &publicType))
        recover();

    if (arrayTypeErrorCheck(indexLocation, publicType) ||
        arrayQualifierErrorCheck(indexLocation, publicType))
    {
        recover();
    }

    TType arrayType(publicType);

    int size;
    if (arraySizeErrorCheck(identifierLocation, indexExpression, size))
    {
        recover();
    }
    // Make the type an array even if size check failed.
    // This ensures useless error messages regarding the variable's non-arrayness won't follow.
    arrayType.setArraySize(size);

    TVariable *variable = nullptr;
    if (!declareVariable(identifierLocation, identifier, arrayType, &variable))
        recover();

    TIntermSymbol *symbol = intermediate.addSymbol(0, identifier, arrayType, identifierLocation);
    if (variable && symbol)
        symbol->setId(variable->getUniqueId());

    return intermediate.makeAggregate(symbol, identifierLocation);
}

TIntermAggregate *TParseContext::parseSingleInitDeclaration(const TPublicType &publicType,
                                                            const TSourceLoc &identifierLocation,
                                                            const TString &identifier,
                                                            const TSourceLoc &initLocation,
                                                            TIntermTyped *initializer)
{
    mDeferredSingleDeclarationErrorCheck = false;

    if (singleDeclarationErrorCheck(publicType, identifierLocation))
        recover();

    TIntermNode *intermNode = nullptr;
    if (!executeInitializer(identifierLocation, identifier, publicType, initializer, &intermNode))
    {
        //
        // Build intermediate representation
        //
        return intermNode ? intermediate.makeAggregate(intermNode, initLocation) : nullptr;
    }
    else
    {
        recover();
        return nullptr;
    }
}

TIntermAggregate *TParseContext::parseSingleArrayInitDeclaration(
    TPublicType &publicType,
    const TSourceLoc &identifierLocation,
    const TString &identifier,
    const TSourceLoc &indexLocation,
    TIntermTyped *indexExpression,
    const TSourceLoc &initLocation,
    TIntermTyped *initializer)
{
    mDeferredSingleDeclarationErrorCheck = false;

    if (singleDeclarationErrorCheck(publicType, identifierLocation))
        recover();

    if (arrayTypeErrorCheck(indexLocation, publicType) ||
        arrayQualifierErrorCheck(indexLocation, publicType))
    {
        recover();
    }

    TPublicType arrayType(publicType);

    int size = 0;
    // If indexExpression is nullptr, then the array will eventually get its size implicitly from
    // the initializer.
    if (indexExpression != nullptr &&
        arraySizeErrorCheck(identifierLocation, indexExpression, size))
    {
        recover();
    }
    // Make the type an array even if size check failed.
    // This ensures useless error messages regarding the variable's non-arrayness won't follow.
    arrayType.setArraySize(size);

    // initNode will correspond to the whole of "type b[n] = initializer".
    TIntermNode *initNode = nullptr;
    if (!executeInitializer(identifierLocation, identifier, arrayType, initializer, &initNode))
    {
        return initNode ? intermediate.makeAggregate(initNode, initLocation) : nullptr;
    }
    else
    {
        recover();
        return nullptr;
    }
}

TIntermAggregate *TParseContext::parseInvariantDeclaration(const TSourceLoc &invariantLoc,
                                                           const TSourceLoc &identifierLoc,
                                                           const TString *identifier,
                                                           const TSymbol *symbol)
{
    // invariant declaration
    if (globalErrorCheck(invariantLoc, symbolTable.atGlobalLevel(), "invariant varying"))
    {
        recover();
    }

    if (!symbol)
    {
        error(identifierLoc, "undeclared identifier declared as invariant", identifier->c_str());
        recover();
        return nullptr;
    }
    else
    {
        const TString kGlFrontFacing("gl_FrontFacing");
        if (*identifier == kGlFrontFacing)
        {
            error(identifierLoc, "identifier should not be declared as invariant",
                  identifier->c_str());
            recover();
            return nullptr;
        }
        symbolTable.addInvariantVarying(std::string(identifier->c_str()));
        const TVariable *variable = getNamedVariable(identifierLoc, identifier, symbol);
        ASSERT(variable);
        const TType &type = variable->getType();
        TIntermSymbol *intermSymbol =
            intermediate.addSymbol(variable->getUniqueId(), *identifier, type, identifierLoc);

        TIntermAggregate *aggregate = intermediate.makeAggregate(intermSymbol, identifierLoc);
        aggregate->setOp(EOpInvariantDeclaration);
        return aggregate;
    }
}

TIntermAggregate *TParseContext::parseDeclarator(TPublicType &publicType,
                                                 TIntermAggregate *aggregateDeclaration,
                                                 const TSourceLoc &identifierLocation,
                                                 const TString &identifier)
{
    // If the declaration starting this declarator list was empty (example: int,), some checks were
    // not performed.
    if (mDeferredSingleDeclarationErrorCheck)
    {
        if (singleDeclarationErrorCheck(publicType, identifierLocation))
            recover();
        mDeferredSingleDeclarationErrorCheck = false;
    }

    if (locationDeclaratorListCheck(identifierLocation, publicType))
        recover();

    if (nonInitErrorCheck(identifierLocation, identifier, &publicType))
        recover();

    TVariable *variable = nullptr;
    if (!declareVariable(identifierLocation, identifier, TType(publicType), &variable))
        recover();

    TIntermSymbol *symbol =
        intermediate.addSymbol(0, identifier, TType(publicType), identifierLocation);
    if (variable && symbol)
        symbol->setId(variable->getUniqueId());

    return intermediate.growAggregate(aggregateDeclaration, symbol, identifierLocation);
}

TIntermAggregate *TParseContext::parseArrayDeclarator(TPublicType &publicType,
                                                      TIntermAggregate *aggregateDeclaration,
                                                      const TSourceLoc &identifierLocation,
                                                      const TString &identifier,
                                                      const TSourceLoc &arrayLocation,
                                                      TIntermTyped *indexExpression)
{
    // If the declaration starting this declarator list was empty (example: int,), some checks were
    // not performed.
    if (mDeferredSingleDeclarationErrorCheck)
    {
        if (singleDeclarationErrorCheck(publicType, identifierLocation))
            recover();
        mDeferredSingleDeclarationErrorCheck = false;
    }

    if (locationDeclaratorListCheck(identifierLocation, publicType))
        recover();

    if (nonInitErrorCheck(identifierLocation, identifier, &publicType))
        recover();

    if (arrayTypeErrorCheck(arrayLocation, publicType) ||
        arrayQualifierErrorCheck(arrayLocation, publicType))
    {
        recover();
    }
    else
    {
        TType arrayType = TType(publicType);
        int size;
        if (arraySizeErrorCheck(arrayLocation, indexExpression, size))
        {
            recover();
        }
        arrayType.setArraySize(size);

        TVariable *variable = nullptr;
        if (!declareVariable(identifierLocation, identifier, arrayType, &variable))
            recover();

        TIntermSymbol *symbol =
            intermediate.addSymbol(0, identifier, arrayType, identifierLocation);
        if (variable && symbol)
            symbol->setId(variable->getUniqueId());

        return intermediate.growAggregate(aggregateDeclaration, symbol, identifierLocation);
    }

    return nullptr;
}

TIntermAggregate *TParseContext::parseInitDeclarator(const TPublicType &publicType,
                                                     TIntermAggregate *aggregateDeclaration,
                                                     const TSourceLoc &identifierLocation,
                                                     const TString &identifier,
                                                     const TSourceLoc &initLocation,
                                                     TIntermTyped *initializer)
{
    // If the declaration starting this declarator list was empty (example: int,), some checks were
    // not performed.
    if (mDeferredSingleDeclarationErrorCheck)
    {
        if (singleDeclarationErrorCheck(publicType, identifierLocation))
            recover();
        mDeferredSingleDeclarationErrorCheck = false;
    }

    if (locationDeclaratorListCheck(identifierLocation, publicType))
        recover();

    TIntermNode *intermNode = nullptr;
    if (!executeInitializer(identifierLocation, identifier, publicType, initializer, &intermNode))
    {
        //
        // build the intermediate representation
        //
        if (intermNode)
        {
            return intermediate.growAggregate(aggregateDeclaration, intermNode, initLocation);
        }
        else
        {
            return aggregateDeclaration;
        }
    }
    else
    {
        recover();
        return nullptr;
    }
}

TIntermAggregate *TParseContext::parseArrayInitDeclarator(const TPublicType &publicType,
                                                          TIntermAggregate *aggregateDeclaration,
                                                          const TSourceLoc &identifierLocation,
                                                          const TString &identifier,
                                                          const TSourceLoc &indexLocation,
                                                          TIntermTyped *indexExpression,
                                                          const TSourceLoc &initLocation,
                                                          TIntermTyped *initializer)
{
    // If the declaration starting this declarator list was empty (example: int,), some checks were
    // not performed.
    if (mDeferredSingleDeclarationErrorCheck)
    {
        if (singleDeclarationErrorCheck(publicType, identifierLocation))
            recover();
        mDeferredSingleDeclarationErrorCheck = false;
    }

    if (locationDeclaratorListCheck(identifierLocation, publicType))
        recover();

    if (arrayTypeErrorCheck(indexLocation, publicType) ||
        arrayQualifierErrorCheck(indexLocation, publicType))
    {
        recover();
    }

    TPublicType arrayType(publicType);

    int size = 0;
    // If indexExpression is nullptr, then the array will eventually get its size implicitly from
    // the initializer.
    if (indexExpression != nullptr &&
        arraySizeErrorCheck(identifierLocation, indexExpression, size))
    {
        recover();
    }
    // Make the type an array even if size check failed.
    // This ensures useless error messages regarding the variable's non-arrayness won't follow.
    arrayType.setArraySize(size);

    // initNode will correspond to the whole of "b[n] = initializer".
    TIntermNode *initNode = nullptr;
    if (!executeInitializer(identifierLocation, identifier, arrayType, initializer, &initNode))
    {
        if (initNode)
        {
            return intermediate.growAggregate(aggregateDeclaration, initNode, initLocation);
        }
        else
        {
            return aggregateDeclaration;
        }
    }
    else
    {
        recover();
        return nullptr;
    }
}

void TParseContext::parseGlobalLayoutQualifier(const TPublicType &typeQualifier)
{
    if (typeQualifier.qualifier != EvqUniform)
    {
        error(typeQualifier.line, "invalid qualifier:", getQualifierString(typeQualifier.qualifier),
              "global layout must be uniform");
        recover();
        return;
    }

    const TLayoutQualifier layoutQualifier = typeQualifier.layoutQualifier;
    ASSERT(!layoutQualifier.isEmpty());

    if (mShaderVersion < 300)
    {
        error(typeQualifier.line, "layout qualifiers supported in GLSL ES 3.00 only", "layout");
        recover();
        return;
    }

    if (layoutLocationErrorCheck(typeQualifier.line, typeQualifier.layoutQualifier))
    {
        recover();
        return;
    }

    if (layoutQualifier.matrixPacking != EmpUnspecified)
    {
        mDefaultMatrixPacking = layoutQualifier.matrixPacking;
    }

    if (layoutQualifier.blockStorage != EbsUnspecified)
    {
        mDefaultBlockStorage = layoutQualifier.blockStorage;
    }
}

void TParseContext::parseFunctionPrototype(const TSourceLoc &location,
                                           TFunction *function,
                                           TIntermAggregate **aggregateOut)
{
    const TSymbol *builtIn =
        symbolTable.findBuiltIn(function->getMangledName(), getShaderVersion());

    if (builtIn)
    {
        error(location, "built-in functions cannot be redefined", function->getName().c_str());
        recover();
    }

    TFunction *prevDec =
        static_cast<TFunction *>(symbolTable.find(function->getMangledName(), getShaderVersion()));
    //
    // Note:  'prevDec' could be 'function' if this is the first time we've seen function
    // as it would have just been put in the symbol table.  Otherwise, we're looking up
    // an earlier occurance.
    //
    if (prevDec->isDefined())
    {
        // Then this function already has a body.
        error(location, "function already has a body", function->getName().c_str());
        recover();
    }
    prevDec->setDefined();
    //
    // Overload the unique ID of the definition to be the same unique ID as the declaration.
    // Eventually we will probably want to have only a single definition and just swap the
    // arguments to be the definition's arguments.
    //
    function->setUniqueId(prevDec->getUniqueId());

    // Raise error message if main function takes any parameters or return anything other than void
    if (function->getName() == "main")
    {
        if (function->getParamCount() > 0)
        {
            error(location, "function cannot take any parameter(s)", function->getName().c_str());
            recover();
        }
        if (function->getReturnType().getBasicType() != EbtVoid)
        {
            error(location, "", function->getReturnType().getBasicString(),
                  "main function cannot return a value");
            recover();
        }
    }

    //
    // Remember the return type for later checking for RETURN statements.
    //
    setCurrentFunctionType(&(prevDec->getReturnType()));
    setFunctionReturnsValue(false);

    //
    // Insert parameters into the symbol table.
    // If the parameter has no name, it's not an error, just don't insert it
    // (could be used for unused args).
    //
    // Also, accumulate the list of parameters into the HIL, so lower level code
    // knows where to find parameters.
    //
    TIntermAggregate *paramNodes = new TIntermAggregate;
    for (size_t i = 0; i < function->getParamCount(); i++)
    {
        const TConstParameter &param = function->getParam(i);
        if (param.name != 0)
        {
            TVariable *variable = new TVariable(param.name, *param.type);
            //
            // Insert the parameters with name in the symbol table.
            //
            if (!symbolTable.declare(variable))
            {
                error(location, "redefinition", variable->getName().c_str());
                recover();
                paramNodes = intermediate.growAggregate(
                    paramNodes, intermediate.addSymbol(0, "", *param.type, location), location);
                continue;
            }

            //
            // Add the parameter to the HIL
            //
            TIntermSymbol *symbol = intermediate.addSymbol(
                variable->getUniqueId(), variable->getName(), variable->getType(), location);

            paramNodes = intermediate.growAggregate(paramNodes, symbol, location);
        }
        else
        {
            paramNodes = intermediate.growAggregate(
                paramNodes, intermediate.addSymbol(0, "", *param.type, location), location);
        }
    }
    intermediate.setAggregateOperator(paramNodes, EOpParameters, location);
    *aggregateOut = paramNodes;
    setLoopNestingLevel(0);
}

TFunction *TParseContext::parseFunctionDeclarator(const TSourceLoc &location, TFunction *function)
{
    //
    // Multiple declarations of the same function are allowed.
    //
    // If this is a definition, the definition production code will check for redefinitions
    // (we don't know at this point if it's a definition or not).
    //
    // Redeclarations are allowed.  But, return types and parameter qualifiers must match.
    //
    TFunction *prevDec =
        static_cast<TFunction *>(symbolTable.find(function->getMangledName(), getShaderVersion()));
    if (prevDec)
    {
        if (prevDec->getReturnType() != function->getReturnType())
        {
            error(location, "overloaded functions must have the same return type",
                  function->getReturnType().getBasicString());
            recover();
        }
        for (size_t i = 0; i < prevDec->getParamCount(); ++i)
        {
            if (prevDec->getParam(i).type->getQualifier() !=
                function->getParam(i).type->getQualifier())
            {
                error(location, "overloaded functions must have the same parameter qualifiers",
                      function->getParam(i).type->getQualifierString());
                recover();
            }
        }
    }

    //
    // Check for previously declared variables using the same name.
    //
    TSymbol *prevSym = symbolTable.find(function->getName(), getShaderVersion());
    if (prevSym)
    {
        if (!prevSym->isFunction())
        {
            error(location, "redefinition", function->getName().c_str(), "function");
            recover();
        }
    }
    else
    {
        // Insert the unmangled name to detect potential future redefinition as a variable.
        TFunction *newFunction =
            new TFunction(NewPoolTString(function->getName().c_str()), &function->getReturnType());
        symbolTable.getOuterLevel()->insertUnmangled(newFunction);
    }

    // We're at the inner scope level of the function's arguments and body statement.
    // Add the function prototype to the surrounding scope instead.
    symbolTable.getOuterLevel()->insert(function);

    //
    // If this is a redeclaration, it could also be a definition, in which case, we want to use the
    // variable names from this one, and not the one that's
    // being redeclared.  So, pass back up this declaration, not the one in the symbol table.
    //
    return function;
}

TFunction *TParseContext::addConstructorFunc(const TPublicType &publicTypeIn)
{
    TPublicType publicType = publicTypeIn;
    if (publicType.isStructSpecifier)
    {
        error(publicType.line, "constructor can't be a structure definition",
              getBasicString(publicType.type));
        recover();
    }

    TOperator op = EOpNull;
    if (publicType.userDef)
    {
        op = EOpConstructStruct;
    }
    else
    {
        switch (publicType.type)
        {
            case EbtFloat:
                if (publicType.isMatrix())
                {
                    switch (publicType.getCols())
                    {
                        case 2:
                            switch (publicType.getRows())
                            {
                                case 2:
                                    op = EOpConstructMat2;
                                    break;
                                case 3:
                                    op = EOpConstructMat2x3;
                                    break;
                                case 4:
                                    op = EOpConstructMat2x4;
                                    break;
                            }
                            break;
                        case 3:
                            switch (publicType.getRows())
                            {
                                case 2:
                                    op = EOpConstructMat3x2;
                                    break;
                                case 3:
                                    op = EOpConstructMat3;
                                    break;
                                case 4:
                                    op = EOpConstructMat3x4;
                                    break;
                            }
                            break;
                        case 4:
                            switch (publicType.getRows())
                            {
                                case 2:
                                    op = EOpConstructMat4x2;
                                    break;
                                case 3:
                                    op = EOpConstructMat4x3;
                                    break;
                                case 4:
                                    op = EOpConstructMat4;
                                    break;
                            }
                            break;
                    }
                }
                else
                {
                    switch (publicType.getNominalSize())
                    {
                        case 1:
                            op = EOpConstructFloat;
                            break;
                        case 2:
                            op = EOpConstructVec2;
                            break;
                        case 3:
                            op = EOpConstructVec3;
                            break;
                        case 4:
                            op = EOpConstructVec4;
                            break;
                    }
                }
                break;

            case EbtInt:
                switch (publicType.getNominalSize())
                {
                    case 1:
                        op = EOpConstructInt;
                        break;
                    case 2:
                        op = EOpConstructIVec2;
                        break;
                    case 3:
                        op = EOpConstructIVec3;
                        break;
                    case 4:
                        op = EOpConstructIVec4;
                        break;
                }
                break;

            case EbtUInt:
                switch (publicType.getNominalSize())
                {
                    case 1:
                        op = EOpConstructUInt;
                        break;
                    case 2:
                        op = EOpConstructUVec2;
                        break;
                    case 3:
                        op = EOpConstructUVec3;
                        break;
                    case 4:
                        op = EOpConstructUVec4;
                        break;
                }
                break;

            case EbtBool:
                switch (publicType.getNominalSize())
                {
                    case 1:
                        op = EOpConstructBool;
                        break;
                    case 2:
                        op = EOpConstructBVec2;
                        break;
                    case 3:
                        op = EOpConstructBVec3;
                        break;
                    case 4:
                        op = EOpConstructBVec4;
                        break;
                }
                break;

            default:
                break;
        }

        if (op == EOpNull)
        {
            error(publicType.line, "cannot construct this type", getBasicString(publicType.type));
            recover();
            publicType.type = EbtFloat;
            op              = EOpConstructFloat;
        }
    }

    TString tempString;
    const TType *type = new TType(publicType);
    return new TFunction(&tempString, type, op);
}

// This function is used to test for the correctness of the parameters passed to various constructor
// functions and also convert them to the right datatype if it is allowed and required.
//
// Returns 0 for an error or the constructed node (aggregate or typed) for no error.
//
TIntermTyped *TParseContext::addConstructor(TIntermNode *arguments,
                                            TType *type,
                                            TOperator op,
                                            TFunction *fnCall,
                                            const TSourceLoc &line)
{
    TIntermAggregate *constructor = arguments->getAsAggregate();
    ASSERT(constructor != nullptr);

    if (type->isArray())
    {
        // GLSL ES 3.00 section 5.4.4: Each argument must be the same type as the element type of
        // the array.
        TIntermSequence *args = constructor->getSequence();
        for (size_t i = 0; i < args->size(); i++)
        {
            const TType &argType = (*args)[i]->getAsTyped()->getType();
            // It has already been checked that the argument is not an array.
            ASSERT(!argType.isArray());
            if (!argType.sameElementType(*type))
            {
                error(line, "Array constructor argument has an incorrect type", "Error");
                recover();
                return nullptr;
            }
        }
    }
    else if (op == EOpConstructStruct)
    {
        const TFieldList &fields = type->getStruct()->fields();
        TIntermSequence *args    = constructor->getSequence();

        for (size_t i = 0; i < fields.size(); i++)
        {
            if (i >= args->size() || (*args)[i]->getAsTyped()->getType() != *fields[i]->type())
            {
                error(line, "Structure constructor arguments do not match structure fields",
                      "Error");
                recover();

                return 0;
            }
        }
    }

    // Turn the argument list itself into a constructor
    constructor->setOp(op);
    constructor->setLine(line);
    ASSERT(constructor->isConstructor());

    // Need to set type before setPrecisionFromChildren() because bool doesn't have precision.
    constructor->setType(*type);

    // Structs should not be precision qualified, the individual members may be.
    // Built-in types on the other hand should be precision qualified.
    if (op != EOpConstructStruct)
    {
        constructor->setPrecisionFromChildren();
        type->setPrecision(constructor->getPrecision());
    }

    TIntermTyped *constConstructor = intermediate.foldAggregateBuiltIn(constructor);
    if (constConstructor)
    {
        return constConstructor;
    }

    return constructor;
}

//
// This function returns the tree representation for the vector field(s) being accessed from contant
// vector.
// If only one component of vector is accessed (v.x or v[0] where v is a contant vector), then a
// contant node is returned, else an aggregate node is returned (for v.xy). The input to this
// function could either be the symbol node or it could be the intermediate tree representation of
// accessing fields in a constant structure or column of a constant matrix.
//
TIntermTyped *TParseContext::addConstVectorNode(TVectorFields &fields,
                                                TIntermConstantUnion *node,
                                                const TSourceLoc &line,
                                                bool outOfRangeIndexIsError)
{
    const TConstantUnion *unionArray = node->getUnionArrayPointer();
    ASSERT(unionArray);

    TConstantUnion *constArray = new TConstantUnion[fields.num];

    for (int i = 0; i < fields.num; i++)
    {
        if (fields.offsets[i] >= node->getType().getNominalSize())
        {
            std::stringstream extraInfoStream;
            extraInfoStream << "vector field selection out of range '" << fields.offsets[i] << "'";
            std::string extraInfo = extraInfoStream.str();
            outOfRangeError(outOfRangeIndexIsError, line, "", "[", extraInfo.c_str());
            fields.offsets[i] = node->getType().getNominalSize() - 1;
        }

        constArray[i] = unionArray[fields.offsets[i]];
    }
    return intermediate.addConstantUnion(constArray, node->getType(), line);
}

//
// This function returns the column being accessed from a constant matrix. The values are retrieved
// from the symbol table and parse-tree is built for a vector (each column of a matrix is a vector).
// The input to the function could either be a symbol node (m[0] where m is a constant matrix)that
// represents a constant matrix or it could be the tree representation of the constant matrix
// (s.m1[0] where s is a constant structure)
//
TIntermTyped *TParseContext::addConstMatrixNode(int index,
                                                TIntermConstantUnion *node,
                                                const TSourceLoc &line,
                                                bool outOfRangeIndexIsError)
{
    if (index >= node->getType().getCols())
    {
        std::stringstream extraInfoStream;
        extraInfoStream << "matrix field selection out of range '" << index << "'";
        std::string extraInfo = extraInfoStream.str();
        outOfRangeError(outOfRangeIndexIsError, line, "", "[", extraInfo.c_str());
        index = node->getType().getCols() - 1;
    }

    const TConstantUnion *unionArray = node->getUnionArrayPointer();
    int size = node->getType().getCols();
    return intermediate.addConstantUnion(&unionArray[size * index], node->getType(), line);
}

//
// This function returns an element of an array accessed from a constant array. The values are
// retrieved from the symbol table and parse-tree is built for the type of the element. The input
// to the function could either be a symbol node (a[0] where a is a constant array)that represents a
// constant array or it could be the tree representation of the constant array (s.a1[0] where s is a
// constant structure)
//
TIntermTyped *TParseContext::addConstArrayNode(int index,
                                               TIntermConstantUnion *node,
                                               const TSourceLoc &line,
                                               bool outOfRangeIndexIsError)
{
    TType arrayElementType = node->getType();
    arrayElementType.clearArrayness();

    if (index >= node->getType().getArraySize())
    {
        std::stringstream extraInfoStream;
        extraInfoStream << "array field selection out of range '" << index << "'";
        std::string extraInfo = extraInfoStream.str();
        outOfRangeError(outOfRangeIndexIsError, line, "", "[", extraInfo.c_str());
        index = node->getType().getArraySize() - 1;
    }
    size_t arrayElementSize          = arrayElementType.getObjectSize();
    const TConstantUnion *unionArray = node->getUnionArrayPointer();
    return intermediate.addConstantUnion(&unionArray[arrayElementSize * index], node->getType(),
                                         line);
}

//
// This function returns the value of a particular field inside a constant structure from the symbol
// table.
// If there is an embedded/nested struct, it appropriately calls addConstStructNested or
// addConstStructFromAggr function and returns the parse-tree with the values of the embedded/nested
// struct.
//
TIntermTyped *TParseContext::addConstStruct(const TString &identifier,
                                            TIntermTyped *node,
                                            const TSourceLoc &line)
{
    const TFieldList &fields = node->getType().getStruct()->fields();
    size_t instanceSize      = 0;

    for (size_t index = 0; index < fields.size(); ++index)
    {
        if (fields[index]->name() == identifier)
        {
            break;
        }
        else
        {
            instanceSize += fields[index]->type()->getObjectSize();
        }
    }

    TIntermTyped *typedNode;
    TIntermConstantUnion *tempConstantNode = node->getAsConstantUnion();
    if (tempConstantNode)
    {
        const TConstantUnion *constArray = tempConstantNode->getUnionArrayPointer();

        // type will be changed in the calling function
        typedNode = intermediate.addConstantUnion(constArray + instanceSize,
                                                  tempConstantNode->getType(), line);
    }
    else
    {
        error(line, "Cannot offset into the structure", "Error");
        recover();

        return 0;
    }

    return typedNode;
}

//
// Interface/uniform blocks
//
TIntermAggregate *TParseContext::addInterfaceBlock(const TPublicType &typeQualifier,
                                                   const TSourceLoc &nameLine,
                                                   const TString &blockName,
                                                   TFieldList *fieldList,
                                                   const TString *instanceName,
                                                   const TSourceLoc &instanceLine,
                                                   TIntermTyped *arrayIndex,
                                                   const TSourceLoc &arrayIndexLine)
{
    if (reservedErrorCheck(nameLine, blockName))
        recover();

    if (typeQualifier.qualifier != EvqUniform)
    {
        error(typeQualifier.line, "invalid qualifier:", getQualifierString(typeQualifier.qualifier),
              "interface blocks must be uniform");
        recover();
    }

    TLayoutQualifier blockLayoutQualifier = typeQualifier.layoutQualifier;
    if (layoutLocationErrorCheck(typeQualifier.line, blockLayoutQualifier))
    {
        recover();
    }

    if (blockLayoutQualifier.matrixPacking == EmpUnspecified)
    {
        blockLayoutQualifier.matrixPacking = mDefaultMatrixPacking;
    }

    if (blockLayoutQualifier.blockStorage == EbsUnspecified)
    {
        blockLayoutQualifier.blockStorage = mDefaultBlockStorage;
    }

    TSymbol *blockNameSymbol = new TInterfaceBlockName(&blockName);
    if (!symbolTable.declare(blockNameSymbol))
    {
        error(nameLine, "redefinition", blockName.c_str(), "interface block name");
        recover();
    }

    // check for sampler types and apply layout qualifiers
    for (size_t memberIndex = 0; memberIndex < fieldList->size(); ++memberIndex)
    {
        TField *field    = (*fieldList)[memberIndex];
        TType *fieldType = field->type();
        if (IsSampler(fieldType->getBasicType()))
        {
            error(field->line(), "unsupported type", fieldType->getBasicString(),
                  "sampler types are not allowed in interface blocks");
            recover();
        }

        const TQualifier qualifier = fieldType->getQualifier();
        switch (qualifier)
        {
            case EvqGlobal:
            case EvqUniform:
                break;
            default:
                error(field->line(), "invalid qualifier on interface block member",
                      getQualifierString(qualifier));
                recover();
                break;
        }

        // check layout qualifiers
        TLayoutQualifier fieldLayoutQualifier = fieldType->getLayoutQualifier();
        if (layoutLocationErrorCheck(field->line(), fieldLayoutQualifier))
        {
            recover();
        }

        if (fieldLayoutQualifier.blockStorage != EbsUnspecified)
        {
            error(field->line(), "invalid layout qualifier:",
                  getBlockStorageString(fieldLayoutQualifier.blockStorage), "cannot be used here");
            recover();
        }

        if (fieldLayoutQualifier.matrixPacking == EmpUnspecified)
        {
            fieldLayoutQualifier.matrixPacking = blockLayoutQualifier.matrixPacking;
        }
        else if (!fieldType->isMatrix() && fieldType->getBasicType() != EbtStruct)
        {
            warning(field->line(), "extraneous layout qualifier:",
                    getMatrixPackingString(fieldLayoutQualifier.matrixPacking),
                    "only has an effect on matrix types");
        }

        fieldType->setLayoutQualifier(fieldLayoutQualifier);
    }

    // add array index
    int arraySize = 0;
    if (arrayIndex != NULL)
    {
        if (arraySizeErrorCheck(arrayIndexLine, arrayIndex, arraySize))
            recover();
    }

    TInterfaceBlock *interfaceBlock =
        new TInterfaceBlock(&blockName, fieldList, instanceName, arraySize, blockLayoutQualifier);
    TType interfaceBlockType(interfaceBlock, typeQualifier.qualifier, blockLayoutQualifier,
                             arraySize);

    TString symbolName = "";
    int symbolId       = 0;

    if (!instanceName)
    {
        // define symbols for the members of the interface block
        for (size_t memberIndex = 0; memberIndex < fieldList->size(); ++memberIndex)
        {
            TField *field    = (*fieldList)[memberIndex];
            TType *fieldType = field->type();

            // set parent pointer of the field variable
            fieldType->setInterfaceBlock(interfaceBlock);

            TVariable *fieldVariable = new TVariable(&field->name(), *fieldType);
            fieldVariable->setQualifier(typeQualifier.qualifier);

            if (!symbolTable.declare(fieldVariable))
            {
                error(field->line(), "redefinition", field->name().c_str(),
                      "interface block member name");
                recover();
            }
        }
    }
    else
    {
        if (reservedErrorCheck(instanceLine, *instanceName))
            recover();

        // add a symbol for this interface block
        TVariable *instanceTypeDef = new TVariable(instanceName, interfaceBlockType, false);
        instanceTypeDef->setQualifier(typeQualifier.qualifier);

        if (!symbolTable.declare(instanceTypeDef))
        {
            error(instanceLine, "redefinition", instanceName->c_str(),
                  "interface block instance name");
            recover();
        }

        symbolId   = instanceTypeDef->getUniqueId();
        symbolName = instanceTypeDef->getName();
    }

    TIntermAggregate *aggregate = intermediate.makeAggregate(
        intermediate.addSymbol(symbolId, symbolName, interfaceBlockType, typeQualifier.line),
        nameLine);
    aggregate->setOp(EOpDeclaration);

    exitStructDeclaration();
    return aggregate;
}

bool TParseContext::enterStructDeclaration(const TSourceLoc &line, const TString &identifier)
{
    ++mStructNestingLevel;

    // Embedded structure definitions are not supported per GLSL ES spec.
    // They aren't allowed in GLSL either, but we need to detect this here
    // so we don't rely on the GLSL compiler to catch it.
    if (mStructNestingLevel > 1)
    {
        error(line, "", "Embedded struct definitions are not allowed");
        return true;
    }

    return false;
}

void TParseContext::exitStructDeclaration()
{
    --mStructNestingLevel;
}

namespace
{
const int kWebGLMaxStructNesting = 4;

}  // namespace

bool TParseContext::structNestingErrorCheck(const TSourceLoc &line, const TField &field)
{
    if (!IsWebGLBasedSpec(mShaderSpec))
    {
        return false;
    }

    if (field.type()->getBasicType() != EbtStruct)
    {
        return false;
    }

    // We're already inside a structure definition at this point, so add
    // one to the field's struct nesting.
    if (1 + field.type()->getDeepestStructNesting() > kWebGLMaxStructNesting)
    {
        std::stringstream reasonStream;
        reasonStream << "Reference of struct type " << field.type()->getStruct()->name().c_str()
                     << " exceeds maximum allowed nesting level of " << kWebGLMaxStructNesting;
        std::string reason = reasonStream.str();
        error(line, reason.c_str(), field.name().c_str(), "");
        return true;
    }

    return false;
}

//
// Parse an array index expression
//
TIntermTyped *TParseContext::addIndexExpression(TIntermTyped *baseExpression,
                                                const TSourceLoc &location,
                                                TIntermTyped *indexExpression)
{
    TIntermTyped *indexedExpression = NULL;

    if (!baseExpression->isArray() && !baseExpression->isMatrix() && !baseExpression->isVector())
    {
        if (baseExpression->getAsSymbolNode())
        {
            error(location, " left of '[' is not of type array, matrix, or vector ",
                  baseExpression->getAsSymbolNode()->getSymbol().c_str());
        }
        else
        {
            error(location, " left of '[' is not of type array, matrix, or vector ", "expression");
        }
        recover();
    }

    TIntermConstantUnion *indexConstantUnion = indexExpression->getAsConstantUnion();

    // TODO(oetuaho@nvidia.com): Get rid of indexConstantUnion == nullptr below once ANGLE is able
    // to constant fold all constant expressions. Right now we don't allow indexing interface blocks
    // or fragment outputs with expressions that ANGLE is not able to constant fold, even if the
    // index is a constant expression.
    if (indexExpression->getQualifier() != EvqConst || indexConstantUnion == nullptr)
    {
        if (baseExpression->isInterfaceBlock())
        {
            error(
                location, "", "[",
                "array indexes for interface blocks arrays must be constant integral expressions");
            recover();
        }
        else if (baseExpression->getQualifier() == EvqFragmentOut)
        {
            error(location, "", "[",
                  "array indexes for fragment outputs must be constant integral expressions");
            recover();
        }
        else if (mShaderSpec == SH_WEBGL2_SPEC && baseExpression->getQualifier() == EvqFragData)
        {
            error(location, "", "[", "array index for gl_FragData must be constant zero");
            recover();
        }
    }

    if (indexConstantUnion)
    {
        // If the index is not qualified as constant, the behavior in the spec is undefined. This
        // applies even if ANGLE has been able to constant fold it (ANGLE may constant fold
        // expressions that are not constant expressions). The most compatible way to handle this
        // case is to report a warning instead of an error and force the index to be in the
        // correct range.
        bool outOfRangeIndexIsError = indexExpression->getQualifier() == EvqConst;
        int index = indexConstantUnion->getIConst(0);
        if (index < 0)
        {
            std::stringstream infoStream;
            infoStream << index;
            std::string info = infoStream.str();
            outOfRangeError(outOfRangeIndexIsError, location, "negative index", info.c_str());
            index = 0;
        }
        TIntermConstantUnion *baseConstantUnion = baseExpression->getAsConstantUnion();
        if (baseConstantUnion)
        {
            if (baseExpression->isArray())
            {
                // constant folding for array indexing
                indexedExpression =
                    addConstArrayNode(index, baseConstantUnion, location, outOfRangeIndexIsError);
            }
            else if (baseExpression->isVector())
            {
                // constant folding for vector indexing
                TVectorFields fields;
                fields.num = 1;
                fields.offsets[0] =
                    index;  // need to do it this way because v.xy sends fields integer array
                indexedExpression =
                    addConstVectorNode(fields, baseConstantUnion, location, outOfRangeIndexIsError);
            }
            else if (baseExpression->isMatrix())
            {
                // constant folding for matrix indexing
                indexedExpression =
                    addConstMatrixNode(index, baseConstantUnion, location, outOfRangeIndexIsError);
            }
        }
        else
        {
            int safeIndex = -1;

            if (baseExpression->isArray())
            {
                if (baseExpression->getQualifier() == EvqFragData && index > 0)
                {
                    if (mShaderSpec == SH_WEBGL2_SPEC)
                    {
                        // Error has been already generated if index is not const.
                        if (indexExpression->getQualifier() == EvqConst)
                        {
                            error(location, "", "[",
                                  "array index for gl_FragData must be constant zero");
                            recover();
                        }
                        safeIndex = 0;
                    }
                    else if (!isExtensionEnabled("GL_EXT_draw_buffers"))
                    {
                        outOfRangeError(outOfRangeIndexIsError, location, "", "[",
                                        "array index for gl_FragData must be zero when "
                                        "GL_EXT_draw_buffers is disabled");
                        safeIndex = 0;
                    }
                }
                // Only do generic out-of-range check if similar error hasn't already been reported.
                if (safeIndex < 0 && index >= baseExpression->getType().getArraySize())
                {
                    std::stringstream extraInfoStream;
                    extraInfoStream << "array index out of range '" << index << "'";
                    std::string extraInfo = extraInfoStream.str();
                    outOfRangeError(outOfRangeIndexIsError, location, "", "[", extraInfo.c_str());
                    safeIndex = baseExpression->getType().getArraySize() - 1;
                }
            }
            else if ((baseExpression->isVector() || baseExpression->isMatrix()) &&
                     baseExpression->getType().getNominalSize() <= index)
            {
                std::stringstream extraInfoStream;
                extraInfoStream << "field selection out of range '" << index << "'";
                std::string extraInfo = extraInfoStream.str();
                outOfRangeError(outOfRangeIndexIsError, location, "", "[", extraInfo.c_str());
                safeIndex = baseExpression->getType().getNominalSize() - 1;
            }

            // Data of constant unions can't be changed, because it may be shared with other
            // constant unions or even builtins, like gl_MaxDrawBuffers. Instead use a new
            // sanitized object.
            if (safeIndex != -1)
            {
                TConstantUnion *safeConstantUnion = new TConstantUnion();
                safeConstantUnion->setIConst(safeIndex);
                indexConstantUnion->replaceConstantUnion(safeConstantUnion);
            }

            indexedExpression =
                intermediate.addIndex(EOpIndexDirect, baseExpression, indexExpression, location);
        }
    }
    else
    {
        indexedExpression =
            intermediate.addIndex(EOpIndexIndirect, baseExpression, indexExpression, location);
    }

    if (indexedExpression == 0)
    {
        TConstantUnion *unionArray = new TConstantUnion[1];
        unionArray->setFConst(0.0f);
        indexedExpression =
            intermediate.addConstantUnion(unionArray, TType(EbtFloat, EbpHigh, EvqConst), location);
    }
    else if (baseExpression->isArray())
    {
        TType indexedType = baseExpression->getType();
        indexedType.clearArrayness();
        indexedExpression->setType(indexedType);
    }
    else if (baseExpression->isMatrix())
    {
        indexedExpression->setType(TType(baseExpression->getBasicType(),
                                         baseExpression->getPrecision(), EvqTemporary,
                                         static_cast<unsigned char>(baseExpression->getRows())));
    }
    else if (baseExpression->isVector())
    {
        indexedExpression->setType(
            TType(baseExpression->getBasicType(), baseExpression->getPrecision(), EvqTemporary));
    }
    else
    {
        indexedExpression->setType(baseExpression->getType());
    }

    if (baseExpression->getType().getQualifier() == EvqConst &&
        indexExpression->getType().getQualifier() == EvqConst)
    {
        indexedExpression->getTypePointer()->setQualifier(EvqConst);
    }
    else
    {
        indexedExpression->getTypePointer()->setQualifier(EvqTemporary);
    }

    return indexedExpression;
}

TIntermTyped *TParseContext::addFieldSelectionExpression(TIntermTyped *baseExpression,
                                                         const TSourceLoc &dotLocation,
                                                         const TString &fieldString,
                                                         const TSourceLoc &fieldLocation)
{
    TIntermTyped *indexedExpression = NULL;

    if (baseExpression->isArray())
    {
        error(fieldLocation, "cannot apply dot operator to an array", ".");
        recover();
    }

    if (baseExpression->isVector())
    {
        TVectorFields fields;
        if (!parseVectorFields(fieldString, baseExpression->getNominalSize(), fields,
                               fieldLocation))
        {
            fields.num        = 1;
            fields.offsets[0] = 0;
            recover();
        }

        if (baseExpression->getAsConstantUnion())
        {
            // constant folding for vector fields
            indexedExpression = addConstVectorNode(fields, baseExpression->getAsConstantUnion(),
                                                   fieldLocation, true);
        }
        else
        {
            TIntermTyped *index = intermediate.addSwizzle(fields, fieldLocation);
            indexedExpression =
                intermediate.addIndex(EOpVectorSwizzle, baseExpression, index, dotLocation);
        }
        if (indexedExpression == nullptr)
        {
            recover();
            indexedExpression = baseExpression;
        }
        else
        {
            // Note that the qualifier set here will be corrected later.
            indexedExpression->setType(TType(baseExpression->getBasicType(),
                                             baseExpression->getPrecision(), EvqTemporary,
                                             (unsigned char)(fieldString).size()));
        }
    }
    else if (baseExpression->getBasicType() == EbtStruct)
    {
        bool fieldFound          = false;
        const TFieldList &fields = baseExpression->getType().getStruct()->fields();
        if (fields.empty())
        {
            error(dotLocation, "structure has no fields", "Internal Error");
            recover();
            indexedExpression = baseExpression;
        }
        else
        {
            unsigned int i;
            for (i = 0; i < fields.size(); ++i)
            {
                if (fields[i]->name() == fieldString)
                {
                    fieldFound = true;
                    break;
                }
            }
            if (fieldFound)
            {
                if (baseExpression->getAsConstantUnion())
                {
                    indexedExpression = addConstStruct(fieldString, baseExpression, dotLocation);
                    if (indexedExpression == 0)
                    {
                        recover();
                        indexedExpression = baseExpression;
                    }
                    else
                    {
                        indexedExpression->setType(*fields[i]->type());
                    }
                }
                else
                {
                    TConstantUnion *unionArray = new TConstantUnion[1];
                    unionArray->setIConst(i);
                    TIntermTyped *index = intermediate.addConstantUnion(
                        unionArray, *fields[i]->type(), fieldLocation);
                    indexedExpression = intermediate.addIndex(EOpIndexDirectStruct, baseExpression,
                                                              index, dotLocation);
                    indexedExpression->setType(*fields[i]->type());
                }
            }
            else
            {
                error(dotLocation, " no such field in structure", fieldString.c_str());
                recover();
                indexedExpression = baseExpression;
            }
        }
    }
    else if (baseExpression->isInterfaceBlock())
    {
        bool fieldFound          = false;
        const TFieldList &fields = baseExpression->getType().getInterfaceBlock()->fields();
        if (fields.empty())
        {
            error(dotLocation, "interface block has no fields", "Internal Error");
            recover();
            indexedExpression = baseExpression;
        }
        else
        {
            unsigned int i;
            for (i = 0; i < fields.size(); ++i)
            {
                if (fields[i]->name() == fieldString)
                {
                    fieldFound = true;
                    break;
                }
            }
            if (fieldFound)
            {
                TConstantUnion *unionArray = new TConstantUnion[1];
                unionArray->setIConst(i);
                TIntermTyped *index =
                    intermediate.addConstantUnion(unionArray, *fields[i]->type(), fieldLocation);
                indexedExpression = intermediate.addIndex(EOpIndexDirectInterfaceBlock,
                                                          baseExpression, index, dotLocation);
                indexedExpression->setType(*fields[i]->type());
            }
            else
            {
                error(dotLocation, " no such field in interface block", fieldString.c_str());
                recover();
                indexedExpression = baseExpression;
            }
        }
    }
    else
    {
        if (mShaderVersion < 300)
        {
            error(dotLocation, " field selection requires structure or vector on left hand side",
                  fieldString.c_str());
        }
        else
        {
            error(dotLocation,
                  " field selection requires structure, vector, or interface block on left hand "
                  "side",
                  fieldString.c_str());
        }
        recover();
        indexedExpression = baseExpression;
    }

    if (baseExpression->getQualifier() == EvqConst)
    {
        indexedExpression->getTypePointer()->setQualifier(EvqConst);
    }
    else
    {
        indexedExpression->getTypePointer()->setQualifier(EvqTemporary);
    }

    return indexedExpression;
}

TLayoutQualifier TParseContext::parseLayoutQualifier(const TString &qualifierType,
                                                     const TSourceLoc &qualifierTypeLine)
{
    TLayoutQualifier qualifier;

    qualifier.location      = -1;
    qualifier.matrixPacking = EmpUnspecified;
    qualifier.blockStorage  = EbsUnspecified;

    if (qualifierType == "shared")
    {
        qualifier.blockStorage = EbsShared;
    }
    else if (qualifierType == "packed")
    {
        qualifier.blockStorage = EbsPacked;
    }
    else if (qualifierType == "std140")
    {
        qualifier.blockStorage = EbsStd140;
    }
    else if (qualifierType == "row_major")
    {
        qualifier.matrixPacking = EmpRowMajor;
    }
    else if (qualifierType == "column_major")
    {
        qualifier.matrixPacking = EmpColumnMajor;
    }
    else if (qualifierType == "location")
    {
        error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str(),
              "location requires an argument");
        recover();
    }
    else
    {
        error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str());
        recover();
    }

    return qualifier;
}

TLayoutQualifier TParseContext::parseLayoutQualifier(const TString &qualifierType,
                                                     const TSourceLoc &qualifierTypeLine,
                                                     const TString &intValueString,
                                                     int intValue,
                                                     const TSourceLoc &intValueLine)
{
    TLayoutQualifier qualifier;

    qualifier.location      = -1;
    qualifier.matrixPacking = EmpUnspecified;
    qualifier.blockStorage  = EbsUnspecified;

    if (qualifierType != "location")
    {
        error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str(),
              "only location may have arguments");
        recover();
    }
    else
    {
        // must check that location is non-negative
        if (intValue < 0)
        {
            error(intValueLine, "out of range:", intValueString.c_str(),
                  "location must be non-negative");
            recover();
        }
        else
        {
            qualifier.location = intValue;
        }
    }

    return qualifier;
}

TLayoutQualifier TParseContext::joinLayoutQualifiers(TLayoutQualifier leftQualifier,
                                                     TLayoutQualifier rightQualifier)
{
    TLayoutQualifier joinedQualifier = leftQualifier;

    if (rightQualifier.location != -1)
    {
        joinedQualifier.location = rightQualifier.location;
    }
    if (rightQualifier.matrixPacking != EmpUnspecified)
    {
        joinedQualifier.matrixPacking = rightQualifier.matrixPacking;
    }
    if (rightQualifier.blockStorage != EbsUnspecified)
    {
        joinedQualifier.blockStorage = rightQualifier.blockStorage;
    }

    return joinedQualifier;
}

TPublicType TParseContext::joinInterpolationQualifiers(const TSourceLoc &interpolationLoc,
                                                       TQualifier interpolationQualifier,
                                                       const TSourceLoc &storageLoc,
                                                       TQualifier storageQualifier)
{
    TQualifier mergedQualifier = EvqSmoothIn;

    if (storageQualifier == EvqFragmentIn)
    {
        if (interpolationQualifier == EvqSmooth)
            mergedQualifier = EvqSmoothIn;
        else if (interpolationQualifier == EvqFlat)
            mergedQualifier = EvqFlatIn;
        else
            UNREACHABLE();
    }
    else if (storageQualifier == EvqCentroidIn)
    {
        if (interpolationQualifier == EvqSmooth)
            mergedQualifier = EvqCentroidIn;
        else if (interpolationQualifier == EvqFlat)
            mergedQualifier = EvqFlatIn;
        else
            UNREACHABLE();
    }
    else if (storageQualifier == EvqVertexOut)
    {
        if (interpolationQualifier == EvqSmooth)
            mergedQualifier = EvqSmoothOut;
        else if (interpolationQualifier == EvqFlat)
            mergedQualifier = EvqFlatOut;
        else
            UNREACHABLE();
    }
    else if (storageQualifier == EvqCentroidOut)
    {
        if (interpolationQualifier == EvqSmooth)
            mergedQualifier = EvqCentroidOut;
        else if (interpolationQualifier == EvqFlat)
            mergedQualifier = EvqFlatOut;
        else
            UNREACHABLE();
    }
    else
    {
        error(interpolationLoc,
              "interpolation qualifier requires a fragment 'in' or vertex 'out' storage qualifier",
              getInterpolationString(interpolationQualifier));
        recover();

        mergedQualifier = storageQualifier;
    }

    TPublicType type;
    type.setBasic(EbtVoid, mergedQualifier, storageLoc);
    return type;
}

TFieldList *TParseContext::addStructDeclaratorList(const TPublicType &typeSpecifier,
                                                   TFieldList *fieldList)
{
    if (voidErrorCheck(typeSpecifier.line, (*fieldList)[0]->name(), typeSpecifier.type))
    {
        recover();
    }

    for (unsigned int i = 0; i < fieldList->size(); ++i)
    {
        //
        // Careful not to replace already known aspects of type, like array-ness
        //
        TType *type = (*fieldList)[i]->type();
        type->setBasicType(typeSpecifier.type);
        type->setPrimarySize(typeSpecifier.primarySize);
        type->setSecondarySize(typeSpecifier.secondarySize);
        type->setPrecision(typeSpecifier.precision);
        type->setQualifier(typeSpecifier.qualifier);
        type->setLayoutQualifier(typeSpecifier.layoutQualifier);

        // don't allow arrays of arrays
        if (type->isArray())
        {
            if (arrayTypeErrorCheck(typeSpecifier.line, typeSpecifier))
                recover();
        }
        if (typeSpecifier.array)
            type->setArraySize(typeSpecifier.arraySize);
        if (typeSpecifier.userDef)
        {
            type->setStruct(typeSpecifier.userDef->getStruct());
        }

        if (structNestingErrorCheck(typeSpecifier.line, *(*fieldList)[i]))
        {
            recover();
        }
    }

    return fieldList;
}

TPublicType TParseContext::addStructure(const TSourceLoc &structLine,
                                        const TSourceLoc &nameLine,
                                        const TString *structName,
                                        TFieldList *fieldList)
{
    TStructure *structure = new TStructure(structName, fieldList);
    TType *structureType  = new TType(structure);

    // Store a bool in the struct if we're at global scope, to allow us to
    // skip the local struct scoping workaround in HLSL.
    structure->setUniqueId(TSymbolTable::nextUniqueId());
    structure->setAtGlobalScope(symbolTable.atGlobalLevel());

    if (!structName->empty())
    {
        if (reservedErrorCheck(nameLine, *structName))
        {
            recover();
        }
        TVariable *userTypeDef = new TVariable(structName, *structureType, true);
        if (!symbolTable.declare(userTypeDef))
        {
            error(nameLine, "redefinition", structName->c_str(), "struct");
            recover();
        }
    }

    // ensure we do not specify any storage qualifiers on the struct members
    for (unsigned int typeListIndex = 0; typeListIndex < fieldList->size(); typeListIndex++)
    {
        const TField &field        = *(*fieldList)[typeListIndex];
        const TQualifier qualifier = field.type()->getQualifier();
        switch (qualifier)
        {
            case EvqGlobal:
            case EvqTemporary:
                break;
            default:
                error(field.line(), "invalid qualifier on struct member",
                      getQualifierString(qualifier));
                recover();
                break;
        }
    }

    TPublicType publicType;
    publicType.setBasic(EbtStruct, EvqTemporary, structLine);
    publicType.userDef = structureType;
    publicType.isStructSpecifier = true;
    exitStructDeclaration();

    return publicType;
}

TIntermSwitch *TParseContext::addSwitch(TIntermTyped *init,
                                        TIntermAggregate *statementList,
                                        const TSourceLoc &loc)
{
    TBasicType switchType = init->getBasicType();
    if ((switchType != EbtInt && switchType != EbtUInt) || init->isMatrix() || init->isArray() ||
        init->isVector())
    {
        error(init->getLine(), "init-expression in a switch statement must be a scalar integer",
              "switch");
        recover();
        return nullptr;
    }

    if (statementList)
    {
        if (!ValidateSwitch::validate(switchType, this, statementList, loc))
        {
            recover();
            return nullptr;
        }
    }

    TIntermSwitch *node = intermediate.addSwitch(init, statementList, loc);
    if (node == nullptr)
    {
        error(loc, "erroneous switch statement", "switch");
        recover();
        return nullptr;
    }
    return node;
}

TIntermCase *TParseContext::addCase(TIntermTyped *condition, const TSourceLoc &loc)
{
    if (mSwitchNestingLevel == 0)
    {
        error(loc, "case labels need to be inside switch statements", "case");
        recover();
        return nullptr;
    }
    if (condition == nullptr)
    {
        error(loc, "case label must have a condition", "case");
        recover();
        return nullptr;
    }
    if ((condition->getBasicType() != EbtInt && condition->getBasicType() != EbtUInt) ||
        condition->isMatrix() || condition->isArray() || condition->isVector())
    {
        error(condition->getLine(), "case label must be a scalar integer", "case");
        recover();
    }
    TIntermConstantUnion *conditionConst = condition->getAsConstantUnion();
    // TODO(oetuaho@nvidia.com): Get rid of the conditionConst == nullptr check once all constant
    // expressions can be folded. Right now we don't allow constant expressions that ANGLE can't
    // fold in case labels.
    if (condition->getQualifier() != EvqConst || conditionConst == nullptr)
    {
        error(condition->getLine(), "case label must be constant", "case");
        recover();
    }
    TIntermCase *node = intermediate.addCase(condition, loc);
    if (node == nullptr)
    {
        error(loc, "erroneous case statement", "case");
        recover();
        return nullptr;
    }
    return node;
}

TIntermCase *TParseContext::addDefault(const TSourceLoc &loc)
{
    if (mSwitchNestingLevel == 0)
    {
        error(loc, "default labels need to be inside switch statements", "default");
        recover();
        return nullptr;
    }
    TIntermCase *node = intermediate.addCase(nullptr, loc);
    if (node == nullptr)
    {
        error(loc, "erroneous default statement", "default");
        recover();
        return nullptr;
    }
    return node;
}

TIntermTyped *TParseContext::createUnaryMath(TOperator op,
                                             TIntermTyped *child,
                                             const TSourceLoc &loc,
                                             const TType *funcReturnType)
{
    if (child == nullptr)
    {
        return nullptr;
    }

    switch (op)
    {
        case EOpLogicalNot:
            if (child->getBasicType() != EbtBool || child->isMatrix() || child->isArray() ||
                child->isVector())
            {
                return nullptr;
            }
            break;
        case EOpBitwiseNot:
            if ((child->getBasicType() != EbtInt && child->getBasicType() != EbtUInt) ||
                child->isMatrix() || child->isArray())
            {
                return nullptr;
            }
            break;
        case EOpPostIncrement:
        case EOpPreIncrement:
        case EOpPostDecrement:
        case EOpPreDecrement:
        case EOpNegative:
        case EOpPositive:
            if (child->getBasicType() == EbtStruct || child->getBasicType() == EbtBool ||
                child->isArray())
            {
                return nullptr;
            }
        // Operators for built-ins are already type checked against their prototype.
        default:
            break;
    }

    return intermediate.addUnaryMath(op, child, loc, funcReturnType);
}

TIntermTyped *TParseContext::addUnaryMath(TOperator op, TIntermTyped *child, const TSourceLoc &loc)
{
    TIntermTyped *node = createUnaryMath(op, child, loc, nullptr);
    if (node == nullptr)
    {
        unaryOpError(loc, GetOperatorString(op), child->getCompleteString());
        recover();
        return child;
    }
    return node;
}

TIntermTyped *TParseContext::addUnaryMathLValue(TOperator op,
                                                TIntermTyped *child,
                                                const TSourceLoc &loc)
{
    if (lValueErrorCheck(loc, GetOperatorString(op), child))
        recover();
    return addUnaryMath(op, child, loc);
}

bool TParseContext::binaryOpCommonCheck(TOperator op,
                                        TIntermTyped *left,
                                        TIntermTyped *right,
                                        const TSourceLoc &loc)
{
    if (left->isArray() || right->isArray())
    {
        if (mShaderVersion < 300)
        {
            error(loc, "Invalid operation for arrays", GetOperatorString(op));
            return false;
        }

        if (left->isArray() != right->isArray())
        {
            error(loc, "array / non-array mismatch", GetOperatorString(op));
            return false;
        }

        switch (op)
        {
            case EOpEqual:
            case EOpNotEqual:
            case EOpAssign:
            case EOpInitialize:
                break;
            default:
                error(loc, "Invalid operation for arrays", GetOperatorString(op));
                return false;
        }
        // At this point, size of implicitly sized arrays should be resolved.
        if (left->getArraySize() != right->getArraySize())
        {
            error(loc, "array size mismatch", GetOperatorString(op));
            return false;
        }
    }

    // Check ops which require integer / ivec parameters
    bool isBitShift = false;
    switch (op)
    {
        case EOpBitShiftLeft:
        case EOpBitShiftRight:
        case EOpBitShiftLeftAssign:
        case EOpBitShiftRightAssign:
            // Unsigned can be bit-shifted by signed and vice versa, but we need to
            // check that the basic type is an integer type.
            isBitShift = true;
            if (!IsInteger(left->getBasicType()) || !IsInteger(right->getBasicType()))
            {
                return false;
            }
            break;
        case EOpBitwiseAnd:
        case EOpBitwiseXor:
        case EOpBitwiseOr:
        case EOpBitwiseAndAssign:
        case EOpBitwiseXorAssign:
        case EOpBitwiseOrAssign:
            // It is enough to check the type of only one operand, since later it
            // is checked that the operand types match.
            if (!IsInteger(left->getBasicType()))
            {
                return false;
            }
            break;
        default:
            break;
    }

    // GLSL ES 1.00 and 3.00 do not support implicit type casting.
    // So the basic type should usually match.
    if (!isBitShift && left->getBasicType() != right->getBasicType())
    {
        return false;
    }

    // Check that type sizes match exactly on ops that require that.
    // Also check restrictions for structs that contain arrays or samplers.
    switch (op)
    {
        case EOpAssign:
        case EOpInitialize:
        case EOpEqual:
        case EOpNotEqual:
            // ESSL 1.00 sections 5.7, 5.8, 5.9
            if (mShaderVersion < 300 && left->getType().isStructureContainingArrays())
            {
                error(loc, "undefined operation for structs containing arrays",
                      GetOperatorString(op));
                return false;
            }
            // Samplers as l-values are disallowed also in ESSL 3.00, see section 4.1.7,
            // we interpret the spec so that this extends to structs containing samplers,
            // similarly to ESSL 1.00 spec.
            if ((mShaderVersion < 300 || op == EOpAssign || op == EOpInitialize) &&
                left->getType().isStructureContainingSamplers())
            {
                error(loc, "undefined operation for structs containing samplers",
                      GetOperatorString(op));
                return false;
            }
        case EOpLessThan:
        case EOpGreaterThan:
        case EOpLessThanEqual:
        case EOpGreaterThanEqual:
            if ((left->getNominalSize() != right->getNominalSize()) ||
                (left->getSecondarySize() != right->getSecondarySize()))
            {
                return false;
            }
        default:
            break;
    }

    return true;
}

TIntermTyped *TParseContext::addBinaryMathInternal(TOperator op,
                                                   TIntermTyped *left,
                                                   TIntermTyped *right,
                                                   const TSourceLoc &loc)
{
    if (!binaryOpCommonCheck(op, left, right, loc))
        return nullptr;

    switch (op)
    {
        case EOpEqual:
        case EOpNotEqual:
            break;
        case EOpLessThan:
        case EOpGreaterThan:
        case EOpLessThanEqual:
        case EOpGreaterThanEqual:
            ASSERT(!left->isArray() && !right->isArray());
            if (left->isMatrix() || left->isVector() || left->getBasicType() == EbtStruct)
            {
                return nullptr;
            }
            break;
        case EOpLogicalOr:
        case EOpLogicalXor:
        case EOpLogicalAnd:
            ASSERT(!left->isArray() && !right->isArray());
            if (left->getBasicType() != EbtBool || left->isMatrix() || left->isVector())
            {
                return nullptr;
            }
            break;
        case EOpAdd:
        case EOpSub:
        case EOpDiv:
        case EOpMul:
            ASSERT(!left->isArray() && !right->isArray());
            if (left->getBasicType() == EbtStruct || left->getBasicType() == EbtBool)
            {
                return nullptr;
            }
            break;
        case EOpIMod:
            ASSERT(!left->isArray() && !right->isArray());
            // Note that this is only for the % operator, not for mod()
            if (left->getBasicType() == EbtStruct || left->getBasicType() == EbtBool ||
                left->getBasicType() == EbtFloat)
            {
                return nullptr;
            }
            break;
        // Note that for bitwise ops, type checking is done in promote() to
        // share code between ops and compound assignment
        default:
            break;
    }

    return intermediate.addBinaryMath(op, left, right, loc);
}

TIntermTyped *TParseContext::addBinaryMath(TOperator op,
                                           TIntermTyped *left,
                                           TIntermTyped *right,
                                           const TSourceLoc &loc)
{
    TIntermTyped *node = addBinaryMathInternal(op, left, right, loc);
    if (node == 0)
    {
        binaryOpError(loc, GetOperatorString(op), left->getCompleteString(),
                      right->getCompleteString());
        recover();
        return left;
    }
    return node;
}

TIntermTyped *TParseContext::addBinaryMathBooleanResult(TOperator op,
                                                        TIntermTyped *left,
                                                        TIntermTyped *right,
                                                        const TSourceLoc &loc)
{
    TIntermTyped *node = addBinaryMathInternal(op, left, right, loc);
    if (node == 0)
    {
        binaryOpError(loc, GetOperatorString(op), left->getCompleteString(),
                      right->getCompleteString());
        recover();
        TConstantUnion *unionArray = new TConstantUnion[1];
        unionArray->setBConst(false);
        return intermediate.addConstantUnion(unionArray, TType(EbtBool, EbpUndefined, EvqConst),
                                             loc);
    }
    return node;
}

TIntermTyped *TParseContext::createAssign(TOperator op,
                                          TIntermTyped *left,
                                          TIntermTyped *right,
                                          const TSourceLoc &loc)
{
    if (binaryOpCommonCheck(op, left, right, loc))
    {
        return intermediate.addAssign(op, left, right, loc);
    }
    return nullptr;
}

TIntermTyped *TParseContext::addAssign(TOperator op,
                                       TIntermTyped *left,
                                       TIntermTyped *right,
                                       const TSourceLoc &loc)
{
    TIntermTyped *node = createAssign(op, left, right, loc);
    if (node == nullptr)
    {
        assignError(loc, "assign", left->getCompleteString(), right->getCompleteString());
        recover();
        return left;
    }
    return node;
}

TIntermTyped *TParseContext::addComma(TIntermTyped *left,
                                      TIntermTyped *right,
                                      const TSourceLoc &loc)
{
    return intermediate.addComma(left, right, loc, mShaderVersion);
}

TIntermBranch *TParseContext::addBranch(TOperator op, const TSourceLoc &loc)
{
    switch (op)
    {
        case EOpContinue:
            if (mLoopNestingLevel <= 0)
            {
                error(loc, "continue statement only allowed in loops", "");
                recover();
            }
            break;
        case EOpBreak:
            if (mLoopNestingLevel <= 0 && mSwitchNestingLevel <= 0)
            {
                error(loc, "break statement only allowed in loops and switch statements", "");
                recover();
            }
            break;
        case EOpReturn:
            if (mCurrentFunctionType->getBasicType() != EbtVoid)
            {
                error(loc, "non-void function must return a value", "return");
                recover();
            }
            break;
        default:
            // No checks for discard
            break;
    }
    return intermediate.addBranch(op, loc);
}

TIntermBranch *TParseContext::addBranch(TOperator op,
                                        TIntermTyped *returnValue,
                                        const TSourceLoc &loc)
{
    ASSERT(op == EOpReturn);
    mFunctionReturnsValue = true;
    if (mCurrentFunctionType->getBasicType() == EbtVoid)
    {
        error(loc, "void function cannot return a value", "return");
        recover();
    }
    else if (*mCurrentFunctionType != returnValue->getType())
    {
        error(loc, "function return is not matching type:", "return");
        recover();
    }
    return intermediate.addBranch(op, returnValue, loc);
}

void TParseContext::checkTextureOffsetConst(TIntermAggregate *functionCall)
{
    ASSERT(!functionCall->isUserDefined());
    const TString &name        = functionCall->getName();
    TIntermNode *offset        = nullptr;
    TIntermSequence *arguments = functionCall->getSequence();
    if (name.compare(0, 16, "texelFetchOffset") == 0 ||
        name.compare(0, 16, "textureLodOffset") == 0 ||
        name.compare(0, 20, "textureProjLodOffset") == 0 ||
        name.compare(0, 17, "textureGradOffset") == 0 ||
        name.compare(0, 21, "textureProjGradOffset") == 0)
    {
        offset = arguments->back();
    }
    else if (name.compare(0, 13, "textureOffset") == 0 ||
             name.compare(0, 17, "textureProjOffset") == 0)
    {
        // A bias parameter might follow the offset parameter.
        ASSERT(arguments->size() >= 3);
        offset = (*arguments)[2];
    }
    if (offset != nullptr)
    {
        TIntermConstantUnion *offsetConstantUnion = offset->getAsConstantUnion();
        if (offset->getAsTyped()->getQualifier() != EvqConst || !offsetConstantUnion)
        {
            TString unmangledName = TFunction::unmangleName(name);
            error(functionCall->getLine(), "Texture offset must be a constant expression",
                  unmangledName.c_str());
            recover();
        }
        else
        {
            ASSERT(offsetConstantUnion->getBasicType() == EbtInt);
            size_t size                  = offsetConstantUnion->getType().getObjectSize();
            const TConstantUnion *values = offsetConstantUnion->getUnionArrayPointer();
            for (size_t i = 0u; i < size; ++i)
            {
                int offsetValue = values[i].getIConst();
                if (offsetValue > mMaxProgramTexelOffset || offsetValue < mMinProgramTexelOffset)
                {
                    std::stringstream tokenStream;
                    tokenStream << offsetValue;
                    std::string token = tokenStream.str();
                    error(offset->getLine(), "Texture offset value out of valid range",
                          token.c_str());
                    recover();
                }
            }
        }
    }
}

TIntermTyped *TParseContext::addFunctionCallOrMethod(TFunction *fnCall,
                                                     TIntermNode *paramNode,
                                                     TIntermNode *thisNode,
                                                     const TSourceLoc &loc,
                                                     bool *fatalError)
{
    *fatalError            = false;
    TOperator op           = fnCall->getBuiltInOp();
    TIntermTyped *callNode = nullptr;

    if (thisNode != nullptr)
    {
        TConstantUnion *unionArray = new TConstantUnion[1];
        int arraySize              = 0;
        TIntermTyped *typedThis = thisNode->getAsTyped();
        if (fnCall->getName() != "length")
        {
            error(loc, "invalid method", fnCall->getName().c_str());
            recover();
        }
        else if (paramNode != nullptr)
        {
            error(loc, "method takes no parameters", "length");
            recover();
        }
        else if (typedThis == nullptr || !typedThis->isArray())
        {
            error(loc, "length can only be called on arrays", "length");
            recover();
        }
        else
        {
            arraySize = typedThis->getArraySize();
            if (typedThis->getAsSymbolNode() == nullptr)
            {
                // This code path can be hit with expressions like these:
                // (a = b).length()
                // (func()).length()
                // (int[3](0, 1, 2)).length()
                // ESSL 3.00 section 5.9 defines expressions so that this is not actually a valid
                // expression.
                // It allows "An array name with the length method applied" in contrast to GLSL 4.4
                // spec section 5.9 which allows "An array, vector or matrix expression with the
                // length method applied".
                error(loc, "length can only be called on array names, not on array expressions",
                      "length");
                recover();
            }
        }
        unionArray->setIConst(arraySize);
        callNode =
            intermediate.addConstantUnion(unionArray, TType(EbtInt, EbpUndefined, EvqConst), loc);
    }
    else if (op != EOpNull)
    {
        //
        // Then this should be a constructor.
        // Don't go through the symbol table for constructors.
        // Their parameters will be verified algorithmically.
        //
        TType type(EbtVoid, EbpUndefined);  // use this to get the type back
        if (!constructorErrorCheck(loc, paramNode, *fnCall, op, &type))
        {
            //
            // It's a constructor, of type 'type'.
            //
            callNode = addConstructor(paramNode, &type, op, fnCall, loc);
        }

        if (callNode == nullptr)
        {
            recover();
            callNode = intermediate.setAggregateOperator(nullptr, op, loc);
        }
        callNode->setType(type);
    }
    else
    {
        //
        // Not a constructor.  Find it in the symbol table.
        //
        const TFunction *fnCandidate;
        bool builtIn;
        fnCandidate = findFunction(loc, fnCall, mShaderVersion, &builtIn);
        if (fnCandidate)
        {
            //
            // A declared function.
            //
            if (builtIn && !fnCandidate->getExtension().empty() &&
                extensionErrorCheck(loc, fnCandidate->getExtension()))
            {
                recover();
            }
            op = fnCandidate->getBuiltInOp();
            if (builtIn && op != EOpNull)
            {
                //
                // A function call mapped to a built-in operation.
                //
                if (fnCandidate->getParamCount() == 1)
                {
                    //
                    // Treat it like a built-in unary operator.
                    //
                    TIntermAggregate *paramAgg = paramNode->getAsAggregate();
                    paramNode                  = paramAgg->getSequence()->front();
                    callNode = createUnaryMath(op, paramNode->getAsTyped(), loc,
                                               &fnCandidate->getReturnType());
                    if (callNode == nullptr)
                    {
                        std::stringstream extraInfoStream;
                        extraInfoStream
                            << "built in unary operator function.  Type: "
                            << static_cast<TIntermTyped *>(paramNode)->getCompleteString();
                        std::string extraInfo = extraInfoStream.str();
                        error(paramNode->getLine(), " wrong operand type", "Internal Error",
                              extraInfo.c_str());
                        *fatalError = true;
                        return nullptr;
                    }
                }
                else
                {
                    TIntermAggregate *aggregate =
                        intermediate.setAggregateOperator(paramNode, op, loc);
                    aggregate->setType(fnCandidate->getReturnType());
                    aggregate->setPrecisionFromChildren();
                    if (aggregate->areChildrenConstQualified())
                    {
                        aggregate->getTypePointer()->setQualifier(EvqConst);
                    }

                    // Some built-in functions have out parameters too.
                    functionCallLValueErrorCheck(fnCandidate, aggregate);

                    // See if we can constant fold a built-in. Note that this may be possible even
                    // if it is not const-qualified.
                    TIntermTyped *foldedNode = intermediate.foldAggregateBuiltIn(aggregate);
                    if (foldedNode)
                    {
                        callNode = foldedNode;
                    }
                    else
                    {
                        callNode = aggregate;
                    }
                }
            }
            else
            {
                // This is a real function call
                TIntermAggregate *aggregate =
                    intermediate.setAggregateOperator(paramNode, EOpFunctionCall, loc);
                aggregate->setType(fnCandidate->getReturnType());

                // this is how we know whether the given function is a builtIn function or a user
                // defined function
                // if builtIn == false, it's a userDefined -> could be an overloaded
                // builtIn function also
                // if builtIn == true, it's definitely a builtIn function with EOpNull
                if (!builtIn)
                    aggregate->setUserDefined();
                aggregate->setName(fnCandidate->getMangledName());
                aggregate->setFunctionId(fnCandidate->getUniqueId());

                // This needs to happen after the name is set
                if (builtIn)
                {
                    aggregate->setBuiltInFunctionPrecision();

                    checkTextureOffsetConst(aggregate);
                }

                callNode = aggregate;

                functionCallLValueErrorCheck(fnCandidate, aggregate);
            }
        }
        else
        {
            // error message was put out by findFunction()
            // Put on a dummy node for error recovery
            TConstantUnion *unionArray = new TConstantUnion[1];
            unionArray->setFConst(0.0f);
            callNode = intermediate.addConstantUnion(unionArray,
                                                     TType(EbtFloat, EbpUndefined, EvqConst), loc);
            recover();
        }
    }
    return callNode;
}

TIntermTyped *TParseContext::addTernarySelection(TIntermTyped *cond,
                                                 TIntermTyped *trueBlock,
                                                 TIntermTyped *falseBlock,
                                                 const TSourceLoc &loc)
{
    if (boolErrorCheck(loc, cond))
        recover();

    if (trueBlock->getType() != falseBlock->getType())
    {
        binaryOpError(loc, ":", trueBlock->getCompleteString(), falseBlock->getCompleteString());
        recover();
        return falseBlock;
    }
    // ESSL1 sections 5.2 and 5.7:
    // ESSL3 section 5.7:
    // Ternary operator is not among the operators allowed for structures/arrays.
    if (trueBlock->isArray() || trueBlock->getBasicType() == EbtStruct)
    {
        error(loc, "ternary operator is not allowed for structures or arrays", ":");
        recover();
        return falseBlock;
    }
    return intermediate.addSelection(cond, trueBlock, falseBlock, loc);
}

//
// Parse an array of strings using yyparse.
//
// Returns 0 for success.
//
int PaParseStrings(size_t count,
                   const char *const string[],
                   const int length[],
                   TParseContext *context)
{
    if ((count == 0) || (string == NULL))
        return 1;

    if (glslang_initialize(context))
        return 1;

    int error = glslang_scan(count, string, length, context);
    if (!error)
        error = glslang_parse(context);

    glslang_finalize(context);

    return (error == 0) && (context->numErrors() == 0) ? 0 : 1;
}
