src/compiler/translator/ParseContext.cpp

//
// 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
//
////////////////////////////////////////////////////////////////////////


//
// 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);
    }
    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());
}

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

// 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.
bool TParseContext::checkCanBeLValue(const TSourceLoc &line, const char *op, TIntermTyped *node)
{
    TIntermSymbol *symNode    = node->getAsSymbolNode();
    TIntermBinary *binaryNode = node->getAsBinaryNode();

    if (binaryNode)
    {
        switch (binaryNode->getOp())
        {
            case EOpIndexDirect:
            case EOpIndexIndirect:
            case EOpIndexDirectStruct:
            case EOpIndexDirectInterfaceBlock:
                return checkCanBeLValue(line, op, binaryNode->getLeft());
            case EOpVectorSwizzle:
            {
                bool ok = checkCanBeLValue(line, op, binaryNode->getLeft());
                if (ok)
                {
                    int offsetCount[4] = {0, 0, 0, 0};

                    TIntermAggregate *swizzleOffsets = binaryNode->getRight()->getAsAggregate();

                    for (const auto &offset : *swizzleOffsets->getSequence())
                    {
                        int value = offset->getAsTyped()->getAsConstantUnion()->getIConst(0);
                        offsetCount[value]++;
                        if (offsetCount[value] > 1)
                        {
                            error(line, " l-value of swizzle cannot have duplicate components", op);
                            return false;
                        }
                    }
                }

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

        return false;
    }

    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;
        case EvqNumWorkGroups:
            message = "can't modify gl_NumWorkGroups";
            break;
        case EvqWorkGroupSize:
            message = "can't modify gl_WorkGroupSize";
            break;
        case EvqWorkGroupID:
            message = "can't modify gl_WorkGroupID";
            break;
        case EvqLocalInvocationID:
            message = "can't modify gl_LocalInvocationID";
            break;
        case EvqGlobalInvocationID:
            message = "can't modify gl_GlobalInvocationID";
            break;
        case EvqLocalInvocationIndex:
            message = "can't modify gl_LocalInvocationIndex";
            break;
        case EvqComputeIn:
            message = "can't modify work group size variable";
            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 false;
    }

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

    //
    // 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 false;
}

// Both test, and if necessary spit out an error, to see if the node is really
// a constant.
void TParseContext::checkIsConst(TIntermTyped *node)
{
    if (node->getQualifier() != EvqConst)
    {
        error(node->getLine(), "constant expression required", "");
    }
}

// Both test, and if necessary spit out an error, to see if the node is really
// an integer.
void TParseContext::checkIsScalarInteger(TIntermTyped *node, const char *token)
{
    if (!node->isScalarInt())
    {
        error(node->getLine(), "integer expression required", token);
    }
}

// Both test, and if necessary spit out an error, to see if we are currently
// globally scoped.
void TParseContext::checkIsAtGlobalLevel(const TSourceLoc &line, const char *token)
{
    if (!symbolTable.atGlobalLevel())
    {
        error(line, "only allowed at global scope", token);
    }
}

// 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.
bool TParseContext::checkIsNotReserved(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 false;
        }
        if (IsWebGLBasedSpec(mShaderSpec))
        {
            if (identifier.compare(0, 6, "webgl_") == 0)
            {
                error(line, reservedErrMsg, "webgl_");
                return false;
            }
            if (identifier.compare(0, 7, "_webgl_") == 0)
            {
                error(line, reservedErrMsg, "_webgl_");
                return false;
            }
            if (mShaderSpec == SH_CSS_SHADERS_SPEC && identifier.compare(0, 4, "css_") == 0)
            {
                error(line, reservedErrMsg, "css_");
                return false;
            }
        }
        if (identifier.find("__") != TString::npos)
        {
            error(line,
                  "identifiers containing two consecutive underscores (__) are reserved as "
                  "possible future keywords",
                  identifier.c_str());
            return false;
        }
    }

    return true;
}

// 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.
bool TParseContext::checkConstructorArguments(const TSourceLoc &line,
                                              TIntermNode *argumentsNode,
                                              const TFunction &function,
                                              TOperator op,
                                              const TType &type)
{
    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 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->isArray())
            arrayArg = true;
    }

    if (type.isArray())
    {
        // The size of an unsized constructor should already have been determined.
        ASSERT(!type.isUnsizedArray());
        if (static_cast<size_t>(type.getArraySize()) != function.getParamCount())
        {
            error(line, "array constructor needs one argument per array element", "constructor");
            return false;
        }
    }

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

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

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

    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 false;
    }

    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 false;
        }
    }

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

    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 false;
        }
        if (argTyped->getBasicType() == EbtVoid)
        {
            error(line, "cannot convert a void", "constructor");
            return false;
        }
    }

    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.
        for (TIntermNode *&argNode : *argumentsAgg->getSequence())
        {
            const TType &argType = argNode->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");
                return false;
            }
        }
    }
    else if (op == EOpConstructStruct)
    {
        const TFieldList &fields = type.getStruct()->fields();
        TIntermSequence *args    = argumentsAgg->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");
                return false;
            }
        }
    }

    return true;
}

// 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::checkIsNonVoid(const TSourceLoc &line,
                                   const TString &identifier,
                                   const TBasicType &type)
{
    if (type == EbtVoid)
    {
        error(line, "illegal use of type 'void'", identifier.c_str());
        return false;
    }

    return true;
}

// This function checks to see if the node (for the expression) contains a scalar boolean expression
// or not.
void TParseContext::checkIsScalarBool(const TSourceLoc &line, const TIntermTyped *type)
{
    if (type->getBasicType() != EbtBool || type->isArray() || type->isMatrix() || type->isVector())
    {
        error(line, "boolean expression expected", "");
    }
}

// This function checks to see if the node (for the expression) contains a scalar boolean expression
// or not.
void TParseContext::checkIsScalarBool(const TSourceLoc &line, const TPublicType &pType)
{
    if (pType.type != EbtBool || pType.isAggregate())
    {
        error(line, "boolean expression expected", "");
    }
}

bool TParseContext::checkIsNotSampler(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 false;
        }

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

    return true;
}

void TParseContext::checkDeclaratorLocationIsNotSpecified(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");
    }
}

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

void TParseContext::checkOutParameterIsNotSampler(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());
    }
}

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.
unsigned int TParseContext::checkIsValidArraySize(const TSourceLoc &line, TIntermTyped *expr)
{
    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", "");
        return 1u;
    }

    unsigned int size = 0u;

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

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

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

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

    // 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 (size > sizeLimit)
    {
        error(line, "array size too large", "");
        return 1u;
    }

    return size;
}

// See if this qualifier can be an array.
bool TParseContext::checkIsValidQualifierForArray(const TSourceLoc &line,
                                                  const TPublicType &elementQualifier)
{
    if ((elementQualifier.qualifier == EvqAttribute) ||
        (elementQualifier.qualifier == EvqVertexIn) ||
        (elementQualifier.qualifier == EvqConst && mShaderVersion < 300))
    {
        error(line, "cannot declare arrays of this qualifier",
              TType(elementQualifier).getQualifierString());
        return false;
    }

    return true;
}

// See if this element type can be formed into an array.
bool TParseContext::checkIsValidTypeForArray(const TSourceLoc &line, const TPublicType &elementType)
{
    //
    // Can the type be an array?
    //
    if (elementType.array)
    {
        error(line, "cannot declare arrays of arrays",
              TType(elementType).getCompleteString().c_str());
        return false;
    }
    // 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 && elementType.type == EbtStruct &&
        sh::IsVarying(elementType.qualifier))
    {
        error(line, "cannot declare arrays of structs of this qualifier",
              TType(elementType).getCompleteString().c_str());
        return false;
    }

    return true;
}

// Check if this qualified element type can be formed into an array.
bool TParseContext::checkIsValidTypeAndQualifierForArray(const TSourceLoc &indexLocation,
                                                         const TPublicType &elementType)
{
    if (checkIsValidTypeForArray(indexLocation, elementType))
    {
        return checkIsValidQualifierForArray(indexLocation, elementType);
    }
    return false;
}

// Enforce non-initializer type/qualifier rules.
void TParseContext::checkCanBeDeclaredWithoutInitializer(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;
    }
    if (type->isUnsizedArray())
    {
        error(line, "implicitly sized arrays need to be initialized", identifier.c_str());
    }
}

// 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 needsReservedCheck = 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 (static_cast<int>(type.getArraySize()) == maxDrawBuffers->getConstPointer()->getIConst())
        {
            if (TSymbol *builtInSymbol = symbolTable.findBuiltIn(identifier, mShaderVersion))
            {
                needsReservedCheck = !checkCanUseExtension(line, builtInSymbol->getExtension());
            }
        }
        else
        {
            error(line, "redeclaration of gl_LastFragData with size != gl_MaxDrawBuffers",
                  identifier.c_str());
            return false;
        }
    }

    if (needsReservedCheck && !checkIsNotReserved(line, identifier))
        return false;

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

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

    return true;
}

void TParseContext::checkIsParameterQualifierValid(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;
    }
    if (qualifier == EvqConst && paramQualifier != EvqIn)
    {
        error(line, "qualifier not allowed with ", getQualifierString(qualifier),
              getQualifierString(paramQualifier));
        return;
    }

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

bool TParseContext::checkCanUseExtension(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 false;
    }
    // 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 false;
    }
    if (iter->second == EBhWarn)
    {
        warning(line, "extension", extension.c_str(), "is being used");
        return true;
    }

    return true;
}

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

        default:
            break;
    }

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

    // 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;
    }

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

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

void TParseContext::checkLayoutQualifierSupported(const TSourceLoc &location,
                                                  const TString &layoutQualifierName,
                                                  int versionRequired)
{

    if (mShaderVersion < versionRequired)
    {
        error(location, "invalid layout qualifier:", layoutQualifierName.c_str(), "not supported");
    }
}

bool TParseContext::checkWorkGroupSizeIsNotSpecified(const TSourceLoc &location,
                                                     const TLayoutQualifier &layoutQualifier)
{
    const TLocalSize &localSize = layoutQualifier.localSize;
    for (size_t i = 0u; i < localSize.size(); ++i)
    {
        if (localSize[i] != -1)
        {
            error(location, "invalid layout qualifier:", getLocalSizeString(i),
                  "only valid when used with 'in' in a compute shader global layout declaration");
            return false;
        }
    }

    return true;
}

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

void TParseContext::checkInvariantIsOutVariableES3(const TQualifier qualifier,
                                                   const TSourceLoc &invariantLocation)
{
    if (!sh::IsVaryingOut(qualifier) && qualifier != EvqFragmentOut)
    {
        error(invariantLocation, "Only out variables can be invariant.", "invariant");
    }
}

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);
}

TLocalSize TParseContext::getComputeShaderLocalSize() const
{
    TLocalSize result;
    for (size_t i = 0u; i < result.size(); ++i)
    {
        if (mComputeShaderLocalSizeDeclared && mComputeShaderLocalSize[i] == -1)
        {
            result[i] = 1;
        }
        else
        {
            result[i] = mComputeShaderLocalSize[i];
        }
    }
    return result;
}

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

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

        // 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());
        }

        // GLSL ES 3.1 Revision 4, 7.1.3 Compute Shader Special Variables
        if (getShaderType() == GL_COMPUTE_SHADER && !mComputeShaderLocalSizeDeclared &&
            qualifier == EvqWorkGroupSize)
        {
            error(location,
                  "It is an error to use gl_WorkGroupSize before declaring the local group size",
                  "gl_WorkGroupSize");
        }
    }

    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;

    checkWorkGroupSizeIsNotSpecified(typeSpecifier.line, layoutQualifier);

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

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

        if ((qualifier == EvqVaryingIn || qualifier == EvqVaryingOut) &&
            (typeSpecifier.type == EbtBool || typeSpecifier.type == EbtInt))
        {
            error(typeSpecifier.line, "cannot be bool or int", getQualifierString(qualifier));
        }
    }
    else
    {
        if (!layoutQualifier.isEmpty())
        {
            checkIsAtGlobalLevel(typeSpecifier.line, "layout");
        }
        if (sh::IsVarying(qualifier) || qualifier == EvqVertexIn || qualifier == EvqFragmentOut)
        {
            checkInputOutputTypeIsValidES3(qualifier, typeSpecifier, typeSpecifier.line);
        }
        if (qualifier == EvqComputeIn)
        {
            error(typeSpecifier.line, "'in' can be only used to specify the local group size",
                  "in");
        }
    }

    return returnType;
}

void TParseContext::checkInputOutputTypeIsValidES3(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));
    }

    // 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));
            }
            // 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));
            }
            // 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));
    }

    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));
        }
        if (type.isStructureContainingArrays())
        {
            error(qualifierLocation, "cannot be a structure containing an array",
                  getQualifierString(qualifier));
        }
        if (type.isStructureContainingType(EbtStruct))
        {
            error(qualifierLocation, "cannot be a structure containing a structure",
                  getQualifierString(qualifier));
        }
        if (type.isStructureContainingType(EbtBool))
        {
            error(qualifierLocation, "cannot be a structure containing a bool",
                  getQualifierString(qualifier));
        }
    }
}

TIntermAggregate *TParseContext::parseSingleDeclaration(TPublicType &publicType,
                                                        const TSourceLoc &identifierOrTypeLocation,
                                                        const TString &identifier)
{
    TType type(publicType);
    if ((mCompileOptions & SH_FLATTEN_PRAGMA_STDGL_INVARIANT_ALL) &&
        mDirectiveHandler.pragma().stdgl.invariantAll)
    {
        TQualifier qualifier = type.getQualifier();

        // The directive handler has already taken care of rejecting invalid uses of this pragma
        // (for example, in ESSL 3.00 fragment shaders), so at this point, flatten it into all
        // affected variable declarations:
        //
        // 1. Built-in special variables which are inputs to the fragment shader. (These are handled
        // elsewhere, in TranslatorGLSL.)
        //
        // 2. Outputs from vertex shaders in ESSL 1.00 and 3.00 (EvqVaryingOut and EvqVertexOut). It
        // is actually less likely that there will be bugs in the handling of ESSL 3.00 shaders, but
        // the way this is currently implemented we have to enable this compiler option before
        // parsing the shader and determining the shading language version it uses. If this were
        // implemented as a post-pass, the workaround could be more targeted.
        //
        // 3. Inputs in ESSL 1.00 fragment shaders (EvqVaryingIn). This is somewhat in violation of
        // the specification, but there are desktop OpenGL drivers that expect that this is the
        // behavior of the #pragma when specified in ESSL 1.00 fragment shaders.
        if (qualifier == EvqVaryingOut || qualifier == EvqVertexOut || qualifier == EvqVaryingIn)
        {
            type.setInvariant(true);
        }
    }

    TIntermSymbol *symbol = intermediate.addSymbol(0, identifier, type, 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
    {
        singleDeclarationErrorCheck(publicType, identifierOrTypeLocation);

        checkCanBeDeclaredWithoutInitializer(identifierOrTypeLocation, identifier, &publicType);

        TVariable *variable = nullptr;
        declareVariable(identifierOrTypeLocation, identifier, type, &variable);

        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;

    singleDeclarationErrorCheck(publicType, identifierLocation);

    checkCanBeDeclaredWithoutInitializer(identifierLocation, identifier, &publicType);

    checkIsValidTypeAndQualifierForArray(indexLocation, publicType);

    TType arrayType(publicType);

    unsigned int size = checkIsValidArraySize(identifierLocation, indexExpression);
    // 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;
    declareVariable(identifierLocation, identifier, arrayType, &variable);

    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;

    singleDeclarationErrorCheck(publicType, identifierLocation);

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

    singleDeclarationErrorCheck(publicType, identifierLocation);

    checkIsValidTypeAndQualifierForArray(indexLocation, publicType);

    TPublicType arrayType(publicType);

    unsigned int size = 0u;
    // If indexExpression is nullptr, then the array will eventually get its size implicitly from
    // the initializer.
    if (indexExpression != nullptr)
    {
        size = checkIsValidArraySize(identifierLocation, indexExpression);
    }
    // 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
    {
        return nullptr;
    }
}

TIntermAggregate *TParseContext::parseInvariantDeclaration(const TSourceLoc &invariantLoc,
                                                           const TSourceLoc &identifierLoc,
                                                           const TString *identifier,
                                                           const TSymbol *symbol)
{
    // invariant declaration
    checkIsAtGlobalLevel(invariantLoc, "invariant varying");

    if (!symbol)
    {
        error(identifierLoc, "undeclared identifier declared as invariant", identifier->c_str());
        return nullptr;
    }
    else
    {
        const TString kGlFrontFacing("gl_FrontFacing");
        if (*identifier == kGlFrontFacing)
        {
            error(identifierLoc, "identifier should not be declared as invariant",
                  identifier->c_str());
            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)
    {
        singleDeclarationErrorCheck(publicType, identifierLocation);
        mDeferredSingleDeclarationErrorCheck = false;
    }

    checkDeclaratorLocationIsNotSpecified(identifierLocation, publicType);

    checkCanBeDeclaredWithoutInitializer(identifierLocation, identifier, &publicType);

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

    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)
    {
        singleDeclarationErrorCheck(publicType, identifierLocation);
        mDeferredSingleDeclarationErrorCheck = false;
    }

    checkDeclaratorLocationIsNotSpecified(identifierLocation, publicType);

    checkCanBeDeclaredWithoutInitializer(identifierLocation, identifier, &publicType);

    if (checkIsValidTypeAndQualifierForArray(arrayLocation, publicType))
    {
        TType arrayType = TType(publicType);
        unsigned int size = checkIsValidArraySize(arrayLocation, indexExpression);
        arrayType.setArraySize(size);

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

        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)
    {
        singleDeclarationErrorCheck(publicType, identifierLocation);
        mDeferredSingleDeclarationErrorCheck = false;
    }

    checkDeclaratorLocationIsNotSpecified(identifierLocation, publicType);

    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
    {
        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)
    {
        singleDeclarationErrorCheck(publicType, identifierLocation);
        mDeferredSingleDeclarationErrorCheck = false;
    }

    checkDeclaratorLocationIsNotSpecified(identifierLocation, publicType);

    checkIsValidTypeAndQualifierForArray(indexLocation, publicType);

    TPublicType arrayType(publicType);

    unsigned int size = 0u;
    // If indexExpression is nullptr, then the array will eventually get its size implicitly from
    // the initializer.
    if (indexExpression != nullptr)
    {
        size = checkIsValidArraySize(identifierLocation, indexExpression);
    }
    // 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
    {
        return nullptr;
    }
}

void TParseContext::parseGlobalLayoutQualifier(const TPublicType &typeQualifier)
{
    const TLayoutQualifier layoutQualifier = typeQualifier.layoutQualifier;

    // It should never be the case, but some strange parser errors can send us here.
    if (layoutQualifier.isEmpty())
    {
        error(typeQualifier.line, "Error during layout qualifier parsing.", "?");
        return;
    }

    if (!layoutQualifier.isCombinationValid())
    {
        error(typeQualifier.line, "invalid combination:", "layout");
        return;
    }

    if (typeQualifier.qualifier == EvqComputeIn)
    {
        if (mComputeShaderLocalSizeDeclared &&
            !layoutQualifier.isLocalSizeEqual(mComputeShaderLocalSize))
        {
            error(typeQualifier.line, "Work group size does not match the previous declaration",
                  "layout");
            return;
        }

        if (mShaderVersion < 310)
        {
            error(typeQualifier.line, "in type qualifier supported in GLSL ES 3.10 only", "layout");
            return;
        }

        if (!layoutQualifier.isGroupSizeSpecified())
        {
            error(typeQualifier.line, "No local work group size specified", "layout");
            return;
        }

        const TVariable *maxComputeWorkGroupSize = static_cast<const TVariable *>(
            symbolTable.findBuiltIn("gl_MaxComputeWorkGroupSize", mShaderVersion));

        const TConstantUnion *maxComputeWorkGroupSizeData =
            maxComputeWorkGroupSize->getConstPointer();

        for (size_t i = 0u; i < layoutQualifier.localSize.size(); ++i)
        {
            if (layoutQualifier.localSize[i] != -1)
            {
                mComputeShaderLocalSize[i]             = layoutQualifier.localSize[i];
                const int maxComputeWorkGroupSizeValue = maxComputeWorkGroupSizeData[i].getIConst();
                if (mComputeShaderLocalSize[i] < 1 ||
                    mComputeShaderLocalSize[i] > maxComputeWorkGroupSizeValue)
                {
                    std::stringstream errorMessageStream;
                    errorMessageStream << "Value must be at least 1 and no greater than "
                                       << maxComputeWorkGroupSizeValue;
                    const std::string &errorMessage = errorMessageStream.str();

                    error(typeQualifier.line, "invalid value:", getLocalSizeString(i),
                          errorMessage.c_str());
                    return;
                }
            }
        }

        mComputeShaderLocalSizeDeclared = true;
    }
    else
    {

        if (!checkWorkGroupSizeIsNotSpecified(typeQualifier.line, typeQualifier.layoutQualifier))
        {
            return;
        }

        if (typeQualifier.qualifier != EvqUniform)
        {
            error(typeQualifier.line, "invalid qualifier:",
                  getQualifierString(typeQualifier.qualifier), "global layout must be uniform");
            return;
        }

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

        checkLocationIsNotSpecified(typeQualifier.line, typeQualifier.layoutQualifier);

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

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

TIntermAggregate *TParseContext::addFunctionPrototypeDeclaration(const TFunction &function,
                                                                 const TSourceLoc &location)
{
    // Note: symbolTableFunction could be the same as function if this is the first declaration.
    // Either way the instance in the symbol table is used to track whether the function is declared
    // multiple times.
    TFunction *symbolTableFunction =
        static_cast<TFunction *>(symbolTable.find(function.getMangledName(), getShaderVersion()));
    if (symbolTableFunction->hasPrototypeDeclaration() && mShaderVersion == 100)
    {
        // ESSL 1.00.17 section 4.2.7.
        // Doesn't apply to ESSL 3.00.4: see section 4.2.3.
        error(location, "duplicate function prototype declarations are not allowed", "function");
    }
    symbolTableFunction->setHasPrototypeDeclaration();

    TIntermAggregate *prototype = new TIntermAggregate;
    prototype->setType(function.getReturnType());
    prototype->setName(function.getMangledName());
    prototype->setFunctionId(function.getUniqueId());

    for (size_t i = 0; i < function.getParamCount(); i++)
    {
        const TConstParameter &param = function.getParam(i);
        if (param.name != 0)
        {
            TVariable variable(param.name, *param.type);

            TIntermSymbol *paramSymbol = intermediate.addSymbol(
                variable.getUniqueId(), variable.getName(), variable.getType(), location);
            prototype = intermediate.growAggregate(prototype, paramSymbol, location);
        }
        else
        {
            TIntermSymbol *paramSymbol = intermediate.addSymbol(0, "", *param.type, location);
            prototype                  = intermediate.growAggregate(prototype, paramSymbol, location);
        }
    }

    prototype->setOp(EOpPrototype);

    symbolTable.pop();

    if (!symbolTable.atGlobalLevel())
    {
        // ESSL 3.00.4 section 4.2.4.
        error(location, "local function prototype declarations are not allowed", "function");
    }

    return prototype;
}

TIntermAggregate *TParseContext::addFunctionDefinition(const TFunction &function,
                                                       TIntermAggregate *functionPrototype,
                                                       TIntermAggregate *functionBody,
                                                       const TSourceLoc &location)
{
    //?? Check that all paths return a value if return type != void ?
    //   May be best done as post process phase on intermediate code
    if (mCurrentFunctionType->getBasicType() != EbtVoid && !mFunctionReturnsValue)
    {
        error(location, "function does not return a value:", "", function.getName().c_str());
    }

    TIntermAggregate *aggregate =
        intermediate.growAggregate(functionPrototype, functionBody, location);
    intermediate.setAggregateOperator(aggregate, EOpFunction, location);
    aggregate->setName(function.getMangledName().c_str());
    aggregate->setType(function.getReturnType());
    aggregate->setFunctionId(function.getUniqueId());

    symbolTable.pop();
    return aggregate;
}

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());
    }

    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());
    }
    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());
        }
        if (function->getReturnType().getBasicType() != EbtVoid)
        {
            error(location, "", function->getReturnType().getBasicString(),
                  "main function cannot return a value");
        }
    }

    //
    // Remember the return type for later checking for RETURN statements.
    //
    mCurrentFunctionType  = &(prevDec->getReturnType());
    mFunctionReturnsValue = 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());
                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)
{
    //
    // We don't know at this point whether this is a function definition or a prototype.
    // The definition production code will check for redefinitions.
    // In the case of ESSL 1.00 the prototype production code will also check for redeclarations.
    //
    // Return types and parameter qualifiers must match in all redeclarations, so those are checked
    // here.
    //
    TFunction *prevDec =
        static_cast<TFunction *>(symbolTable.find(function->getMangledName(), getShaderVersion()));

    if (getShaderVersion() >= 300 && symbolTable.hasUnmangledBuiltIn(function->getName().c_str()))
    {
        // With ESSL 3.00, names of built-in functions cannot be redeclared as functions.
        // Therefore overloading or redefining builtin functions is an error.
        error(location, "Name of a built-in function cannot be redeclared as function",
              function->getName().c_str());
    }
    else if (prevDec)
    {
        if (prevDec->getReturnType() != function->getReturnType())
        {
            error(location, "overloaded functions must have the same return type",
                  function->getReturnType().getBasicString());
        }
        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());
            }
        }
    }

    //
    // 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");
        }
    }
    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::parseFunctionHeader(const TPublicType &type,
                                              const TString *name,
                                              const TSourceLoc &location)
{
    if (type.qualifier != EvqGlobal && type.qualifier != EvqTemporary)
    {
        error(location, "no qualifiers allowed for function return",
              getQualifierString(type.qualifier));
    }
    if (!type.layoutQualifier.isEmpty())
    {
        error(location, "no qualifiers allowed for function return", "layout");
    }
    // make sure a sampler is not involved as well...
    checkIsNotSampler(location, type, "samplers can't be function return values");
    if (mShaderVersion < 300)
    {
        // Array return values are forbidden, but there's also no valid syntax for declaring array
        // return values in ESSL 1.00.
        ASSERT(type.arraySize == 0 || mDiagnostics.numErrors() > 0);

        if (type.isStructureContainingArrays())
        {
            // ESSL 1.00.17 section 6.1 Function Definitions
            error(location, "structures containing arrays can't be function return values",
                  TType(type).getCompleteString().c_str());
        }
    }

    // Add the function as a prototype after parsing it (we do not support recursion)
    return new TFunction(name, new TType(type));
}

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));
    }

    TOperator op = EOpNull;
    if (publicType.userDef)
    {
        op = EOpConstructStruct;
    }
    else
    {
        op = sh::TypeToConstructorOperator(TType(publicType));
        if (op == EOpNull)
        {
            error(publicType.line, "cannot construct this type", getBasicString(publicType.type));
            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 a node to add to the tree regardless of if an error was generated or not.
//
TIntermTyped *TParseContext::addConstructor(TIntermNode *arguments,
                                            TOperator op,
                                            TFunction *fnCall,
                                            const TSourceLoc &line)
{
    TType type = fnCall->getReturnType();
    if (type.isUnsizedArray())
    {
        type.setArraySize(static_cast<unsigned int>(fnCall->getParamCount()));
    }
    bool constType = true;
    for (size_t i = 0; i < fnCall->getParamCount(); ++i)
    {
        const TConstParameter &param = fnCall->getParam(i);
        if (param.type->getQualifier() != EvqConst)
            constType = false;
    }
    if (constType)
        type.setQualifier(EvqConst);

    if (!checkConstructorArguments(line, arguments, *fnCall, op, type))
    {
        TIntermTyped *dummyNode = intermediate.setAggregateOperator(nullptr, op, line);
        dummyNode->setType(type);
        return dummyNode;
    }
    TIntermAggregate *constructor = arguments->getAsAggregate();
    ASSERT(constructor != nullptr);

    // 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());
    }

    constructor->setType(type);

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

    return constructor;
}

// This function returns vector field(s) being accessed from a constant vector.
TIntermConstantUnion *TParseContext::foldVectorSwizzle(TVectorFields &fields,
                                                       TIntermConstantUnion *baseNode,
                                                       const TSourceLoc &location)
{
    const TConstantUnion *unionArray = baseNode->getUnionArrayPointer();
    ASSERT(unionArray);

    TConstantUnion *constArray = new TConstantUnion[fields.num];
    const auto &type           = baseNode->getType();

    for (int i = 0; i < fields.num; i++)
    {
        // Out-of-range indices should already be checked.
        ASSERT(fields.offsets[i] < type.getNominalSize());
        constArray[i] = unionArray[fields.offsets[i]];
    }
    return intermediate.addConstantUnion(constArray, type, location);
}

// This function returns the column vector being accessed from a constant matrix.
TIntermConstantUnion *TParseContext::foldMatrixSubscript(int index,
                                                         TIntermConstantUnion *baseNode,
                                                         const TSourceLoc &location)
{
    ASSERT(index < baseNode->getType().getCols());

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

// This function returns an element of an array accessed from a constant array.
TIntermConstantUnion *TParseContext::foldArraySubscript(int index,
                                                        TIntermConstantUnion *baseNode,
                                                        const TSourceLoc &location)
{
    ASSERT(index < static_cast<int>(baseNode->getArraySize()));

    TType arrayElementType = baseNode->getType();
    arrayElementType.clearArrayness();
    size_t arrayElementSize          = arrayElementType.getObjectSize();
    const TConstantUnion *unionArray = baseNode->getUnionArrayPointer();
    return intermediate.addConstantUnion(&unionArray[arrayElementSize * index], baseNode->getType(),
                                         location);
}

//
// 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");
        return nullptr;
    }

    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)
{
    checkIsNotReserved(nameLine, blockName);

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

    TLayoutQualifier blockLayoutQualifier = typeQualifier.layoutQualifier;
    checkLocationIsNotSpecified(typeQualifier.line, blockLayoutQualifier);

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

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

    checkWorkGroupSizeIsNotSpecified(nameLine, blockLayoutQualifier);

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

    // 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");
        }

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

        // check layout qualifiers
        TLayoutQualifier fieldLayoutQualifier = fieldType->getLayoutQualifier();
        checkLocationIsNotSpecified(field->line(), fieldLayoutQualifier);

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

        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
    unsigned int arraySize = 0;
    if (arrayIndex != nullptr)
    {
        arraySize = checkIsValidArraySize(arrayIndexLine, arrayIndex);
    }

    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");
            }
        }
    }
    else
    {
        checkIsNotReserved(instanceLine, *instanceName);

        // 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");
        }

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

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

    exitStructDeclaration();
    return aggregate;
}

void 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");
    }
}

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

namespace
{
const int kWebGLMaxStructNesting = 4;

}  // namespace

void TParseContext::checkIsBelowStructNestingLimit(const TSourceLoc &line, const TField &field)
{
    if (!IsWebGLBasedSpec(mShaderSpec))
    {
        return;
    }

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

    // 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;
    }
}

//
// 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");
        }
    }

    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");
        }
        else if (baseExpression->getQualifier() == EvqFragmentOut)
        {
            error(location, "", "[",
                  "array indexes for fragment outputs must be constant integral expressions");
        }
        else if (mShaderSpec == SH_WEBGL2_SPEC && baseExpression->getQualifier() == EvqFragData)
        {
            error(location, "", "[", "array index for gl_FragData must be constant zero");
        }
    }

    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 (!baseExpression->isArray())
        {
            // Array checks are done later because a different error message might be generated
            // based on the index in some cases.
            if (baseExpression->isVector())
            {
                index = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                             baseExpression->getType().getNominalSize(),
                                             "vector field selection out of range", "[]");
            }
            else if (baseExpression->isMatrix())
            {
                index = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                             baseExpression->getType().getCols(),
                                             "matrix field selection out of range", "[]");
            }
        }

        TIntermConstantUnion *baseConstantUnion = baseExpression->getAsConstantUnion();
        if (baseConstantUnion)
        {
            if (baseExpression->isArray())
            {
                index = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                             baseExpression->getArraySize(),
                                             "array index out of range", "[]");
                // Constant folding for array indexing.
                indexedExpression = foldArraySubscript(index, baseConstantUnion, location);
            }
            else if (baseExpression->isVector())
            {
                // Constant folding for vector indexing - reusing vector swizzle folding.
                TVectorFields fields;
                fields.num = 1;
                fields.offsets[0] = index;
                indexedExpression = foldVectorSwizzle(fields, baseConstantUnion, location);
            }
            else if (baseExpression->isMatrix())
            {
                // Constant folding for matrix indexing.
                indexedExpression = foldMatrixSubscript(index, baseConstantUnion, location);
            }
        }
        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");
                        }
                        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)
                {
                    safeIndex = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                                     baseExpression->getArraySize(),
                                                     "array index out of range", "[]");
                }
            }

            // 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;
}

int TParseContext::checkIndexOutOfRange(bool outOfRangeIndexIsError,
                                        const TSourceLoc &location,
                                        int index,
                                        int arraySize,
                                        const char *reason,
                                        const char *token)
{
    if (index >= arraySize || index < 0)
    {
        std::stringstream extraInfoStream;
        extraInfoStream << "'" << index << "'";
        std::string extraInfo = extraInfoStream.str();
        outOfRangeError(outOfRangeIndexIsError, location, reason, token, extraInfo.c_str());
        if (index < 0)
        {
            return 0;
        }
        else
        {
            return arraySize - 1;
        }
    }
    return index;
}

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", ".");
    }

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

        if (baseExpression->getAsConstantUnion())
        {
            // constant folding for vector fields
            indexedExpression =
                foldVectorSwizzle(fields, baseExpression->getAsConstantUnion(), fieldLocation);
        }
        else
        {
            TIntermTyped *index = intermediate.addSwizzle(fields, fieldLocation);
            indexedExpression =
                intermediate.addIndex(EOpVectorSwizzle, baseExpression, index, dotLocation);
        }
        if (indexedExpression == nullptr)
        {
            indexedExpression = baseExpression;
        }
        else
        {
            // Note that the qualifier set here will be corrected later.
            indexedExpression->setType(TType(baseExpression->getBasicType(),
                                             baseExpression->getPrecision(), EvqTemporary,
                                             static_cast<unsigned char>(fields.num)));
        }
    }
    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");
            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)
                    {
                        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());
                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");
            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());
                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());
        }
        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 = TLayoutQualifier::create();

    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");
    }
    else
    {
        error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str());
    }

    return qualifier;
}

void TParseContext::parseLocalSize(const TString &qualifierType,
                                   const TSourceLoc &qualifierTypeLine,
                                   int intValue,
                                   const TSourceLoc &intValueLine,
                                   const std::string &intValueString,
                                   size_t index,
                                   TLocalSize *localSize)
{
    checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
    if (intValue < 1)
    {
        std::string errorMessage = std::string(getLocalSizeString(index)) + " must be positive";
        error(intValueLine, "out of range:", intValueString.c_str(), errorMessage.c_str());
    }
    (*localSize)[index] = intValue;
}

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

    std::string intValueString = Str(intValue);

    if (qualifierType == "location")
    {
        // must check that location is non-negative
        if (intValue < 0)
        {
            error(intValueLine, "out of range:", intValueString.c_str(),
                  "location must be non-negative");
        }
        else
        {
            qualifier.location = intValue;
        }
    }
    else if (qualifierType == "local_size_x")
    {
        parseLocalSize(qualifierType, qualifierTypeLine, intValue, intValueLine, intValueString, 0u,
                       &qualifier.localSize);
    }
    else if (qualifierType == "local_size_y")
    {
        parseLocalSize(qualifierType, qualifierTypeLine, intValue, intValueLine, intValueString, 1u,
                       &qualifier.localSize);
    }
    else if (qualifierType == "local_size_z")
    {
        parseLocalSize(qualifierType, qualifierTypeLine, intValue, intValueLine, intValueString, 2u,
                       &qualifier.localSize);
    }
    else
    {
        error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str());
    }

    return qualifier;
}

TLayoutQualifier TParseContext::joinLayoutQualifiers(TLayoutQualifier leftQualifier,
                                                     TLayoutQualifier rightQualifier,
                                                     const TSourceLoc &rightQualifierLocation)
{
    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;
    }

    for (size_t i = 0u; i < rightQualifier.localSize.size(); ++i)
    {
        if (rightQualifier.localSize[i] != -1)
        {
            if (joinedQualifier.localSize[i] != -1 &&
                joinedQualifier.localSize[i] != rightQualifier.localSize[i])
            {
                error(rightQualifierLocation,
                      "Cannot have multiple different work group size specifiers",
                      getLocalSizeString(i));
            }
            joinedQualifier.localSize[i] = rightQualifier.localSize[i];
        }
    }

    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));

        mergedQualifier = storageQualifier;
    }

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

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

    checkWorkGroupSizeIsNotSpecified(typeSpecifier.line, typeSpecifier.layoutQualifier);

    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())
        {
            checkIsValidTypeForArray(typeSpecifier.line, typeSpecifier);
        }
        if (typeSpecifier.array)
            type->setArraySize(static_cast<unsigned int>(typeSpecifier.arraySize));
        if (typeSpecifier.userDef)
        {
            type->setStruct(typeSpecifier.userDef->getStruct());
        }

        checkIsBelowStructNestingLimit(typeSpecifier.line, *(*fieldList)[i]);
    }

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

    // 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));
                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");
        return nullptr;
    }

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

    TIntermSwitch *node = intermediate.addSwitch(init, statementList, loc);
    if (node == nullptr)
    {
        error(loc, "erroneous switch statement", "switch");
        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");
        return nullptr;
    }
    if (condition == nullptr)
    {
        error(loc, "case label must have a condition", "case");
        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");
    }
    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");
    }
    TIntermCase *node = intermediate.addCase(condition, loc);
    if (node == nullptr)
    {
        error(loc, "erroneous case statement", "case");
        return nullptr;
    }
    return node;
}

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

TIntermTyped *TParseContext::addUnaryMathLValue(TOperator op,
                                                TIntermTyped *child,
                                                const TSourceLoc &loc)
{
    checkCanBeLValue(loc, GetOperatorString(op), child);
    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());
        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());
        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());
        return left;
    }
    return node;
}

TIntermTyped *TParseContext::addComma(TIntermTyped *left,
                                      TIntermTyped *right,
                                      const TSourceLoc &loc)
{
    // WebGL2 section 5.26, the following results in an error:
    // "Sequence operator applied to void, arrays, or structs containing arrays"
    if (mShaderSpec == SH_WEBGL2_SPEC && (left->isArray() || left->getBasicType() == EbtVoid ||
                                          left->getType().isStructureContainingArrays() ||
                                          right->isArray() || right->getBasicType() == EbtVoid ||
                                          right->getType().isStructureContainingArrays()))
    {
        error(loc,
              "sequence operator is not allowed for void, arrays, or structs containing arrays",
              ",");
    }

    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", "");
            }
            break;
        case EOpBreak:
            if (mLoopNestingLevel <= 0 && mSwitchNestingLevel <= 0)
            {
                error(loc, "break statement only allowed in loops and switch statements", "");
            }
            break;
        case EOpReturn:
            if (mCurrentFunctionType->getBasicType() != EbtVoid)
            {
                error(loc, "non-void function must return a value", "return");
            }
            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");
    }
    else if (*mCurrentFunctionType != returnValue->getType())
    {
        error(loc, "function return is not matching type:", "return");
    }
    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());
        }
        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());
                }
            }
        }
    }
}

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());
        }
        else if (paramNode != nullptr)
        {
            error(loc, "method takes no parameters", "length");
        }
        else if (typedThis == nullptr || !typedThis->isArray())
        {
            error(loc, "length can only be called on arrays", "length");
        }
        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");
            }
        }
        unionArray->setIConst(arraySize);
        callNode =
            intermediate.addConstantUnion(unionArray, TType(EbtInt, EbpUndefined, EvqConst), loc);
    }
    else if (op != EOpNull)
    {
        // Then this should be a constructor.
        callNode = addConstructor(paramNode, op, fnCall, loc);
    }
    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())
            {
                checkCanUseExtension(loc, fnCandidate->getExtension());
            }
            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);
        }
    }
    return callNode;
}

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

    if (trueBlock->getType() != falseBlock->getType())
    {
        binaryOpError(loc, ":", trueBlock->getCompleteString(), falseBlock->getCompleteString());
        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", ":");
        return falseBlock;
    }
    // WebGL2 section 5.26, the following results in an error:
    // "Ternary operator applied to void, arrays, or structs containing arrays"
    if (mShaderSpec == SH_WEBGL2_SPEC && trueBlock->getBasicType() == EbtVoid)
    {
        error(loc, "ternary operator is not allowed for void", ":");
        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;
}