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kc3-lang/angle/src/compiler/ParseHelper.cpp

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  • Author : alokp@chromium.org
    Date : 2010-09-09 17:30:03
    Hash : 8815d7f2
    Message : Added support for associating functions with extensions and performing validation when those functions are used in a shader. BUG=25 Review URL: http://codereview.appspot.com/2141046 git-svn-id: https://angleproject.googlecode.com/svn/trunk@415 736b8ea6-26fd-11df-bfd4-992fa37f6226

  • src/compiler/ParseHelper.cpp
  • //
    // Copyright (c) 2002-2010 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/ParseHelper.h"
    
    #include <stdarg.h>
    #include <stdio.h>
    
    #include "compiler/osinclude.h"
    #include "compiler/InitializeParseContext.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, int 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;
    }
    
    
    //
    // Look at a '.' field selector string and change it into offsets
    // for a matrix.
    //
    bool TParseContext::parseMatrixFields(const TString& compString, int matSize, TMatrixFields& fields, int line)
    {
        fields.wholeRow = false;
        fields.wholeCol = false;
        fields.row = -1;
        fields.col = -1;
    
        if (compString.size() != 2) {
            error(line, "illegal length of matrix field selection", compString.c_str(), "");
            return false;
        }
    
        if (compString[0] == '_') {
            if (compString[1] < '0' || compString[1] > '3') {
                error(line, "illegal matrix field selection", compString.c_str(), "");
                return false;
            }
            fields.wholeCol = true;
            fields.col = compString[1] - '0';
        } else if (compString[1] == '_') {
            if (compString[0] < '0' || compString[0] > '3') {
                error(line, "illegal matrix field selection", compString.c_str(), "");
                return false;
            }
            fields.wholeRow = true;
            fields.row = compString[0] - '0';
        } else {
            if (compString[0] < '0' || compString[0] > '3' ||
                compString[1] < '0' || compString[1] > '3') {
                error(line, "illegal matrix field selection", compString.c_str(), "");
                return false;
            }
            fields.row = compString[0] - '0';
            fields.col = compString[1] - '0';
        }
    
        if (fields.row >= matSize || fields.col >= matSize) {
            error(line, "matrix field selection out of range", compString.c_str(), "");
            return false;
        }
    
        return true;
    }
    
    ///////////////////////////////////////////////////////////////////////
    //
    // Errors
    //
    ////////////////////////////////////////////////////////////////////////
    
    //
    // Track whether errors have occurred.
    //
    void TParseContext::recover()
    {
        recoveredFromError = true;
    }
    
    //
    // Used by flex/bison to output all syntax and parsing errors.
    //
    void TParseContext::error(TSourceLoc nLine, const char *szReason, const char *szToken, 
                              const char *szExtraInfoFormat, ...)
    {
        char szExtraInfo[400];
        va_list marker;
    
        va_start(marker, szExtraInfoFormat);
    
        vsnprintf(szExtraInfo, sizeof(szExtraInfo), szExtraInfoFormat, marker);
    
        /* VC++ format: file(linenum) : error #: 'token' : extrainfo */
        infoSink.info.prefix(EPrefixError);
        infoSink.info.location(nLine);
        infoSink.info << "'" << szToken <<  "' : " << szReason << " " << szExtraInfo << "\n";
    
        va_end(marker);
    
        ++numErrors;
    }
    
    //
    // Same error message for all places assignments don't work.
    //
    void TParseContext::assignError(int line, const char* op, TString left, TString right)
    {
        error(line, "", op, "cannot convert from '%s' to '%s'",
              right.c_str(), left.c_str());
    }
    
    //
    // Same error message for all places unary operations don't work.
    //
    void TParseContext::unaryOpError(int line, const char* op, TString operand)
    {
       error(line, " wrong operand type", op, 
              "no operation '%s' exists that takes an operand of type %s (or there is no acceptable conversion)",
              op, operand.c_str());
    }
    
    //
    // Same error message for all binary operations don't work.
    //
    void TParseContext::binaryOpError(int line, const char* op, TString left, TString right)
    {
        error(line, " wrong operand types ", op, 
                "no operation '%s' exists that takes a left-hand operand of type '%s' and "
                "a right operand of type '%s' (or there is no acceptable conversion)", 
                op, left.c_str(), right.c_str());
    }
    
    bool TParseContext::precisionErrorCheck(int line, TPrecision precision, TBasicType type){
        switch( type ){
        case EbtFloat:
            if( precision == EbpUndefined ){
                error( line, "No precision specified for (float)", "", "" );
                return true;
            }
            break;
        case EbtInt:
            if( precision == EbpUndefined ){
                error( line, "No precision specified (int)", "", "" );
                return true;
            }
            break;
        }
        return false;
    }
    
    //
    // Both test and if necessary, spit out an error, to see if the node is really
    // an l-value that can be operated on this way.
    //
    // Returns true if the was an error.
    //
    bool TParseContext::lValueErrorCheck(int line, const char* op, TIntermTyped* node)
    {
        TIntermSymbol* symNode = node->getAsSymbolNode();
        TIntermBinary* binaryNode = node->getAsBinaryNode();
    
        if (binaryNode) {
            bool errorReturn;
    
            switch(binaryNode->getOp()) {
            case EOpIndexDirect:
            case EOpIndexIndirect:
            case EOpIndexDirectStruct:
                return lValueErrorCheck(line, op, binaryNode->getLeft());
            case EOpVectorSwizzle:
                errorReturn = lValueErrorCheck(line, op, binaryNode->getLeft());
                if (!errorReturn) {
                    int offset[4] = {0,0,0,0};
    
                    TIntermTyped* rightNode = binaryNode->getRight();
                    TIntermAggregate *aggrNode = rightNode->getAsAggregate();
                    
                    for (TIntermSequence::iterator p = aggrNode->getSequence().begin(); 
                                                   p != aggrNode->getSequence().end(); p++) {
                        int value = (*p)->getAsTyped()->getAsConstantUnion()->getUnionArrayPointer()->getIConst();
                        offset[value]++;     
                        if (offset[value] > 1) {
                            error(line, " l-value of swizzle cannot have duplicate components", op, "", "");
    
                            return true;
                        }
                    }
                } 
    
                return errorReturn;
            default: 
                break;
            }
            error(line, " l-value required", op, "", "");
    
            return true;
        }
    
    
        const char* symbol = 0;
        if (symNode != 0)
            symbol = symNode->getSymbol().c_str();
    
        const char* message = 0;
        switch (node->getQualifier()) {
        case EvqConst:          message = "can't modify a const";        break;
        case EvqConstReadOnly:  message = "can't modify a const";        break;
        case EvqAttribute:      message = "can't modify an attribute";   break;
        case EvqUniform:        message = "can't modify a uniform";      break;
        case EvqVaryingIn:      message = "can't modify a varying";      break;
        case EvqInput:          message = "can't modify an input";       break;
        case EvqFragCoord:      message = "can't modify gl_FragCoord";   break;
        case EvqFrontFacing:    message = "can't modify gl_FrontFacing"; break;
        case EvqPointCoord:     message = "can't modify gl_PointCoord";  break;
        default:
    
            //
            // Type that can't be written to?
            //
            switch (node->getBasicType()) {
            case EbtSampler2D:
            case EbtSamplerCube:
                message = "can't modify a sampler";
                break;
            case EbtVoid:
                message = "can't modify void";
                break;
            default: 
                break;
            }
        }
    
        if (message == 0 && binaryNode == 0 && symNode == 0) {
            error(line, " l-value required", op, "", "");
    
            return true;
        }
    
    
        //
        // Everything else is okay, no error.
        //
        if (message == 0)
            return false;
    
        //
        // If we get here, we have an error and a message.
        //
        if (symNode)
            error(line, " l-value required", op, "\"%s\" (%s)", symbol, message);
        else
            error(line, " l-value required", op, "(%s)", message);
    
        return true;
    }
    
    //
    // Both test, and if necessary spit out an error, to see if the node is really
    // a constant.
    //
    // Returns true if the was an error.
    //
    bool TParseContext::constErrorCheck(TIntermTyped* node)
    {
        if (node->getQualifier() == EvqConst)
            return false;
    
        error(node->getLine(), "constant expression required", "", "");
    
        return true;
    }
    
    //
    // Both test, and if necessary spit out an error, to see if the node is really
    // an integer.
    //
    // Returns true if the was an error.
    //
    bool TParseContext::integerErrorCheck(TIntermTyped* node, const char* token)
    {
        if (node->getBasicType() == EbtInt && node->getNominalSize() == 1)
            return false;
    
        error(node->getLine(), "integer expression required", token, "");
    
        return true;
    }
    
    //
    // Both test, and if necessary spit out an error, to see if we are currently
    // globally scoped.
    //
    // Returns true if the was an error.
    //
    bool TParseContext::globalErrorCheck(int line, bool global, const char* token)
    {
        if (global)
            return false;
    
        error(line, "only allowed at global scope", token, "");
    
        return true;
    }
    
    //
    // For now, keep it simple:  if it starts "gl_", it's reserved, independent
    // of scope.  Except, if the symbol table is at the built-in push-level,
    // which is when we are parsing built-ins.
    // Also checks for "webgl_" and "_webgl_" reserved identifiers if parsing a
    // webgl shader.
    //
    // Returns true if there was an error.
    //
    bool TParseContext::reservedErrorCheck(int line, const TString& identifier)
    {
        static const char* reservedErrMsg = "reserved built-in name";
        if (!symbolTable.atBuiltInLevel()) {
            if (identifier.substr(0, 3) == TString("gl_")) {
                error(line, reservedErrMsg, "gl_", "");
                return true;
            }
            if (spec == EShSpecWebGL) {
                if (identifier.substr(0, 6) == TString("webgl_")) {
                    error(line, reservedErrMsg, "webgl_", "");
                    return true;
                }
                if (identifier.substr(0, 7) == TString("_webgl_")) {
                    error(line, reservedErrMsg, "_webgl_", "");
                    return true;
                }
            }
            if (identifier.find("__") != TString::npos) {
                //error(line, "Two consecutive underscores are reserved for future use.", identifier.c_str(), "", "");
                //return true;
                infoSink.info.message(EPrefixWarning, "Two consecutive underscores are reserved for future use.", line);
                return false;
            }
        }
    
        return false;
    }
    
    //
    // Make sure there is enough data provided to the constructor to build
    // something of the type of the constructor.  Also returns the type of
    // the constructor.
    //
    // Returns true if there was an error in construction.
    //
    bool TParseContext::constructorErrorCheck(int line, TIntermNode* node, TFunction& function, TOperator op, TType* type)
    {
        *type = function.getReturnType();
    
        bool constructingMatrix = false;
        switch(op) {
        case EOpConstructMat2:
        case EOpConstructMat3:
        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.
        //
    
        int size = 0;
        bool constType = true;
        bool full = false;
        bool overFull = false;
        bool matrixInMatrix = false;
        bool arrayArg = false;
        for (int i = 0; i < function.getParamCount(); ++i) {
            const TParameter& param = function.getParam(i);
            size += param.type->getObjectSize();
            
            if (constructingMatrix && param.type->isMatrix())
                matrixInMatrix = true;
            if (full)
                overFull = true;
            if (op != EOpConstructStruct && !type->isArray() && size >= type->getObjectSize())
                full = true;
            if (param.type->getQualifier() != EvqConst)
                constType = false;
            if (param.type->isArray())
                arrayArg = true;
        }
        
        if (constType)
            type->setQualifier(EvqConst);
    
        if (type->isArray() && type->getArraySize() != function.getParamCount()) {
            error(line, "array constructor needs one argument per array element", "constructor", "");
            return true;
        }
    
        if (arrayArg && op != EOpConstructStruct) {
            error(line, "constructing from a non-dereferenced array", "constructor", "");
            return true;
        }
    
        if (matrixInMatrix && !type->isArray()) {
            if (function.getParamCount() != 1) {
              error(line, "constructing matrix from matrix can only take one argument", "constructor", "");
              return true;
            }
        }
    
        if (overFull) {
            error(line, "too many arguments", "constructor", "");
            return true;
        }
        
        if (op == EOpConstructStruct && !type->isArray() && type->getStruct()->size() != function.getParamCount()) {
            error(line, "Number of constructor parameters does not match the number of structure fields", "constructor", "");
            return true;
        }
    
        if (!type->isMatrix()) {
            if ((op != EOpConstructStruct && size != 1 && size < type->getObjectSize()) ||
                (op == EOpConstructStruct && size < type->getObjectSize())) {
                error(line, "not enough data provided for construction", "constructor", "");
                return true;
            }
        }
    
        TIntermTyped* typed = node->getAsTyped();
        if (typed == 0) {
            error(line, "constructor argument does not have a type", "constructor", "");
            return true;
        }
        if (op != EOpConstructStruct && IsSampler(typed->getBasicType())) {
            error(line, "cannot convert a sampler", "constructor", "");
            return true;
        }
        if (typed->getBasicType() == EbtVoid) {
            error(line, "cannot convert a void", "constructor", "");
            return true;
        }
    
        return false;
    }
    
    // This function checks to see if a void variable has been declared and raise an error message for such a case
    //
    // returns true in case of an error
    //
    bool TParseContext::voidErrorCheck(int line, const TString& identifier, const TPublicType& pubType)
    {
        if (pubType.type == EbtVoid) {
            error(line, "illegal use of type 'void'", identifier.c_str(), "");
            return true;
        } 
    
        return false;
    }
    
    // This function checks to see if the node (for the expression) contains a scalar boolean expression or not
    //
    // returns true in case of an error
    //
    bool TParseContext::boolErrorCheck(int line, const TIntermTyped* type)
    {
        if (type->getBasicType() != EbtBool || type->isArray() || type->isMatrix() || type->isVector()) {
            error(line, "boolean expression expected", "", "");
            return true;
        } 
    
        return false;
    }
    
    // This function checks to see if the node (for the expression) contains a scalar boolean expression or not
    //
    // returns true in case of an error
    //
    bool TParseContext::boolErrorCheck(int line, const TPublicType& pType)
    {
        if (pType.type != EbtBool || pType.array || pType.matrix || (pType.size > 1)) {
            error(line, "boolean expression expected", "", "");
            return true;
        } 
    
        return false;
    }
    
    bool TParseContext::samplerErrorCheck(int line, const TPublicType& pType, const char* reason)
    {
        if (pType.type == EbtStruct) {
            if (containsSampler(*pType.userDef)) {
                error(line, reason, getBasicString(pType.type), "(structure contains a sampler)");
            
                return true;
            }
            
            return false;
        } else if (IsSampler(pType.type)) {
            error(line, reason, getBasicString(pType.type), "");
    
            return true;
        }
    
        return false;
    }
    
    bool TParseContext::structQualifierErrorCheck(int line, const TPublicType& pType)
    {
        if ((pType.qualifier == EvqVaryingIn || pType.qualifier == EvqVaryingOut || pType.qualifier == EvqAttribute) &&
            pType.type == EbtStruct) {
            error(line, "cannot be used with a structure", getQualifierString(pType.qualifier), "");
            
            return true;
        }
    
        if (pType.qualifier != EvqUniform && samplerErrorCheck(line, pType, "samplers must be uniform"))
            return true;
    
        return false;
    }
    
    bool TParseContext::parameterSamplerErrorCheck(int line, TQualifier qualifier, const TType& type)
    {
        if ((qualifier == EvqOut || qualifier == EvqInOut) && 
                 type.getBasicType() != EbtStruct && IsSampler(type.getBasicType())) {
            error(line, "samplers cannot be output parameters", type.getBasicString(), "");
            return true;
        }
    
        return false;
    }
    
    bool TParseContext::containsSampler(TType& type)
    {
        if (IsSampler(type.getBasicType()))
            return true;
    
        if (type.getBasicType() == EbtStruct) {
            TTypeList& structure = *type.getStruct();
            for (unsigned int i = 0; i < structure.size(); ++i) {
                if (containsSampler(*structure[i].type))
                    return true;
            }
        }
    
        return false;
    }
    
    //
    // Do size checking for an array type's size.
    //
    // Returns true if there was an error.
    //
    bool TParseContext::arraySizeErrorCheck(int line, TIntermTyped* expr, int& size)
    {
        TIntermConstantUnion* constant = expr->getAsConstantUnion();
        if (constant == 0 || constant->getBasicType() != EbtInt) {
            error(line, "array size must be a constant integer expression", "", "");
            return true;
        }
    
        size = constant->getUnionArrayPointer()->getIConst();
    
        if (size <= 0) {
            error(line, "array size must be a positive integer", "", "");
            size = 1;
            return true;
        }
    
        return false;
    }
    
    //
    // See if this qualifier can be an array.
    //
    // Returns true if there is an error.
    //
    bool TParseContext::arrayQualifierErrorCheck(int line, TPublicType type)
    {
        if ((type.qualifier == EvqAttribute) || (type.qualifier == EvqConst)) {
            error(line, "cannot declare arrays of this qualifier", TType(type).getCompleteString().c_str(), "");
            return true;
        }
    
        return false;
    }
    
    //
    // See if this type can be an array.
    //
    // Returns true if there is an error.
    //
    bool TParseContext::arrayTypeErrorCheck(int line, TPublicType type)
    {
        //
        // Can the type be an array?
        //
        if (type.array) {
            error(line, "cannot declare arrays of arrays", TType(type).getCompleteString().c_str(), "");
            return true;
        }
    
        return false;
    }
    
    //
    // Do all the semantic checking for declaring an array, with and 
    // without a size, and make the right changes to the symbol table.
    //
    // size == 0 means no specified size.
    //
    // Returns true if there was an error.
    //
    bool TParseContext::arrayErrorCheck(int line, TString& identifier, TPublicType type, TVariable*& variable)
    {
        //
        // Don't check for reserved word use until after we know it's not in the symbol table,
        // because reserved arrays can be redeclared.
        //
    
        bool builtIn = false; 
        bool sameScope = false;
        TSymbol* symbol = symbolTable.find(identifier, &builtIn, &sameScope);
        if (symbol == 0 || !sameScope) {
            if (reservedErrorCheck(line, identifier))
                return true;
            
            variable = new TVariable(&identifier, TType(type));
    
            if (type.arraySize)
                variable->getType().setArraySize(type.arraySize);
    
            if (! symbolTable.insert(*variable)) {
                delete variable;
                error(line, "INTERNAL ERROR inserting new symbol", identifier.c_str(), "");
                return true;
            }
        } else {
            if (! symbol->isVariable()) {
                error(line, "variable expected", identifier.c_str(), "");
                return true;
            }
    
            variable = static_cast<TVariable*>(symbol);
            if (! variable->getType().isArray()) {
                error(line, "redeclaring non-array as array", identifier.c_str(), "");
                return true;
            }
            if (variable->getType().getArraySize() > 0) {
                error(line, "redeclaration of array with size", identifier.c_str(), "");
                return true;
            }
            
            if (! variable->getType().sameElementType(TType(type))) {
                error(line, "redeclaration of array with a different type", identifier.c_str(), "");
                return true;
            }
    
            TType* t = variable->getArrayInformationType();
            while (t != 0) {
                if (t->getMaxArraySize() > type.arraySize) {
                    error(line, "higher index value already used for the array", identifier.c_str(), "");
                    return true;
                }
                t->setArraySize(type.arraySize);
                t = t->getArrayInformationType();
            }
    
            if (type.arraySize)
                variable->getType().setArraySize(type.arraySize);
        } 
    
        if (voidErrorCheck(line, identifier, type))
            return true;
    
        return false;
    }
    
    bool TParseContext::arraySetMaxSize(TIntermSymbol *node, TType* type, int size, bool updateFlag, TSourceLoc line)
    {
        bool builtIn = false;
        TSymbol* symbol = symbolTable.find(node->getSymbol(), &builtIn);
        if (symbol == 0) {
            error(line, " undeclared identifier", node->getSymbol().c_str(), "");
            return true;
        }
        TVariable* variable = static_cast<TVariable*>(symbol);
    
        type->setArrayInformationType(variable->getArrayInformationType());
        variable->updateArrayInformationType(type);
    
        // special casing to test index value of gl_FragData. If the accessed index is >= gl_MaxDrawBuffers
        // its an error
        if (node->getSymbol() == "gl_FragData") {
            TSymbol* fragData = symbolTable.find("gl_MaxDrawBuffers", &builtIn);
            if (fragData == 0) {
                infoSink.info.message(EPrefixInternalError, "gl_MaxDrawBuffers not defined", line);
                return true;
            }
    
            int fragDataValue = static_cast<TVariable*>(fragData)->getConstPointer()[0].getIConst();
            if (fragDataValue <= size) {
                error(line, "", "[", "gl_FragData can only have a max array size of up to gl_MaxDrawBuffers", "");
                return true;
            }
        }
    
        // we dont want to update the maxArraySize when this flag is not set, we just want to include this 
        // node type in the chain of node types so that its updated when a higher maxArraySize comes in.
        if (!updateFlag)
            return false;
    
        size++;
        variable->getType().setMaxArraySize(size);
        type->setMaxArraySize(size);
        TType* tt = type;
    
        while(tt->getArrayInformationType() != 0) {
            tt = tt->getArrayInformationType();
            tt->setMaxArraySize(size);
        }
    
        return false;
    }
    
    //
    // Enforce non-initializer type/qualifier rules.
    //
    // Returns true if there was an error.
    //
    bool TParseContext::nonInitConstErrorCheck(int line, TString& identifier, TPublicType& type)
    {
        //
        // Make the qualifier make sense.
        //
        if (type.qualifier == EvqConst) {
            type.qualifier = EvqTemporary;
            error(line, "variables with qualifier 'const' must be initialized", identifier.c_str(), "");
            return true;
        }
    
        return false;
    }
    
    //
    // Do semantic checking for a variable declaration that has no initializer,
    // and update the symbol table.
    //
    // Returns true if there was an error.
    //
    bool TParseContext::nonInitErrorCheck(int line, TString& identifier, TPublicType& type)
    {
        if (reservedErrorCheck(line, identifier))
            recover();
    
        TVariable* variable = new TVariable(&identifier, TType(type));
    
        if (! symbolTable.insert(*variable)) {
            error(line, "redefinition", variable->getName().c_str(), "");
            delete variable;
            return true;
        }
    
        if (voidErrorCheck(line, identifier, type))
            return true;
    
        return false;
    }
    
    bool TParseContext::paramErrorCheck(int line, TQualifier qualifier, TQualifier paramQualifier, TType* type)
    {    
        if (qualifier != EvqConst && qualifier != EvqTemporary) {
            error(line, "qualifier not allowed on function parameter", getQualifierString(qualifier), "");
            return true;
        }
        if (qualifier == EvqConst && paramQualifier != EvqIn) {
            error(line, "qualifier not allowed with ", getQualifierString(qualifier), getQualifierString(paramQualifier));
            return true;
        }
    
        if (qualifier == EvqConst)
            type->setQualifier(EvqConstReadOnly);
        else
            type->setQualifier(paramQualifier);
    
        return false;
    }
    
    bool TParseContext::extensionErrorCheck(int line, const TString& extension)
    {
        TExtensionBehavior::const_iterator iter = extensionBehavior.find(extension);
        if (iter == extensionBehavior.end()) {
            error(line, "extension", extension.c_str(), "is not supported");
            return true;
        }
        if (iter->second == EBhDisable) {
            error(line, "extension", extension.c_str(), "is disabled");
            return true;
        }
        if (iter->second == EBhWarn) {
            TString msg = "extension " + extension + " is being used";
            infoSink.info.message(EPrefixWarning, msg.c_str(), line);
            return false;
        }
    
        return false;
    }
    
    /////////////////////////////////////////////////////////////////////////////////
    //
    // Non-Errors.
    //
    /////////////////////////////////////////////////////////////////////////////////
    
    //
    // 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(int line, TFunction* call, bool *builtIn)
    {
        // First find by unmangled name to check whether the function name has been
        // hidden by a variable name or struct typename.
        const TSymbol* symbol = symbolTable.find(call->getName(), builtIn);
        if (symbol == 0) {
            symbol = symbolTable.find(call->getMangledName(), 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.
    //
    bool TParseContext::executeInitializer(TSourceLoc line, TString& identifier, TPublicType& pType, 
                                           TIntermTyped* initializer, TIntermNode*& intermNode, TVariable* variable)
    {
        TType type = TType(pType);
    
        if (variable == 0) {
            if (reservedErrorCheck(line, identifier))
                return true;
    
            if (voidErrorCheck(line, identifier, pType))
                return true;
    
            //
            // add variable to symbol table
            //
            variable = new TVariable(&identifier, type);
            if (! symbolTable.insert(*variable)) {
                error(line, "redefinition", variable->getName().c_str(), "");
                return true;
                // don't delete variable, it's used by error recovery, and the pool 
                // pop will take care of the memory
            }
        }
    
        //
        // 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()) {
                error(line, " assigning non-constant to", "=", "'%s'", variable->getType().getCompleteString().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;
            }
            if (initializer->getAsConstantUnion()) { 
                ConstantUnion* unionArray = variable->getConstPointer();
    
                if (type.getObjectSize() == 1 && type.getBasicType() != EbtStruct) {
                    *unionArray = (initializer->getAsConstantUnion()->getUnionArrayPointer())[0];
                } else {
                    variable->shareConstPointer(initializer->getAsConstantUnion()->getUnionArrayPointer());
                }
            } else if (initializer->getAsSymbolNode()) {
                const TSymbol* symbol = symbolTable.find(initializer->getAsSymbolNode()->getSymbol());
                const TVariable* tVar = static_cast<const TVariable*>(symbol);
    
                ConstantUnion* constArray = tVar->getConstPointer();
                variable->shareConstPointer(constArray);
            } else {
                error(line, " cannot assign to", "=", "'%s'", variable->getType().getCompleteString().c_str());
                variable->getType().setQualifier(EvqTemporary);
                return true;
            }
        }
     
        if (qualifier != EvqConst) {
            TIntermSymbol* intermSymbol = intermediate.addSymbol(variable->getUniqueId(), variable->getName(), variable->getType(), line);
            intermNode = intermediate.addAssign(EOpInitialize, intermSymbol, initializer, line);
            if (intermNode == 0) {
                assignError(line, "=", intermSymbol->getCompleteString(), initializer->getCompleteString());
                return true;
            }
        } else 
            intermNode = 0;
    
        return false;
    }
    
    bool TParseContext::areAllChildConst(TIntermAggregate* aggrNode)
    {
        if (!aggrNode->isConstructor())
            return false;
    
        bool allConstant = true;
    
        // check if all the child nodes are constants so that they can be inserted into 
        // the parent node
        if (aggrNode) {
            TIntermSequence &childSequenceVector = aggrNode->getSequence() ;
            for (TIntermSequence::iterator p = childSequenceVector.begin(); 
                                        p != childSequenceVector.end(); p++) {
                if (!(*p)->getAsTyped()->getAsConstantUnion())
                    return false;
            }
        }
    
        return allConstant;
    }
    
    // This function is used to test for the correctness of the parameters passed to various constructor functions
    // and also convert them to the right datatype if it is allowed and required. 
    //
    // Returns 0 for an error or the constructed node (aggregate or typed) for no error.
    //
    TIntermTyped* TParseContext::addConstructor(TIntermNode* node, const TType* type, TOperator op, TFunction* fnCall, TSourceLoc line)
    {
        if (node == 0)
            return 0;
    
        TIntermAggregate* aggrNode = node->getAsAggregate();
        
        TTypeList::const_iterator memberTypes;
        if (op == EOpConstructStruct)
            memberTypes = type->getStruct()->begin();
        
        TType elementType = *type;
        if (type->isArray())
            elementType.clearArrayness();
    
        bool singleArg;
        if (aggrNode) {
            if (aggrNode->getOp() != EOpNull || aggrNode->getSequence().size() == 1)
                singleArg = true;
            else
                singleArg = false;
        } else
            singleArg = true;
    
        TIntermTyped *newNode;
        if (singleArg) {
            // If structure constructor or array constructor is being called 
            // for only one parameter inside the structure, we need to call constructStruct function once.
            if (type->isArray())
                newNode = constructStruct(node, &elementType, 1, node->getLine(), false);
            else if (op == EOpConstructStruct)
                newNode = constructStruct(node, (*memberTypes).type, 1, node->getLine(), false);
            else
                newNode = constructBuiltIn(type, op, node, node->getLine(), false);
    
            if (newNode && newNode->getAsAggregate()) {
                TIntermTyped* constConstructor = foldConstConstructor(newNode->getAsAggregate(), *type);
                if (constConstructor)
                    return constConstructor;
            }
    
            return newNode;
        }
        
        //
        // Handle list of arguments.
        //
        TIntermSequence &sequenceVector = aggrNode->getSequence() ;    // Stores the information about the parameter to the constructor
        // if the structure constructor contains more than one parameter, then construct
        // each parameter
        
        int paramCount = 0;  // keeps a track of the constructor parameter number being checked    
        
        // for each parameter to the constructor call, check to see if the right type is passed or convert them 
        // to the right type if possible (and allowed).
        // for structure constructors, just check if the right type is passed, no conversion is allowed.
        
        for (TIntermSequence::iterator p = sequenceVector.begin(); 
                                       p != sequenceVector.end(); p++, paramCount++) {
            if (type->isArray())
                newNode = constructStruct(*p, &elementType, paramCount+1, node->getLine(), true);
            else if (op == EOpConstructStruct)
                newNode = constructStruct(*p, (memberTypes[paramCount]).type, paramCount+1, node->getLine(), true);
            else
                newNode = constructBuiltIn(type, op, *p, node->getLine(), true);
            
            if (newNode) {
                *p = newNode;
            }
        }
    
        TIntermTyped* constructor = intermediate.setAggregateOperator(aggrNode, op, line);
        TIntermTyped* constConstructor = foldConstConstructor(constructor->getAsAggregate(), *type);
        if (constConstructor)
            return constConstructor;
    
        return constructor;
    }
    
    TIntermTyped* TParseContext::foldConstConstructor(TIntermAggregate* aggrNode, const TType& type)
    {
        bool canBeFolded = areAllChildConst(aggrNode);
        aggrNode->setType(type);
        if (canBeFolded) {
            bool returnVal = false;
            ConstantUnion* unionArray = new ConstantUnion[type.getObjectSize()];
            if (aggrNode->getSequence().size() == 1)  {
                returnVal = intermediate.parseConstTree(aggrNode->getLine(), aggrNode, unionArray, aggrNode->getOp(), symbolTable,  type, true);
            }
            else {
                returnVal = intermediate.parseConstTree(aggrNode->getLine(), aggrNode, unionArray, aggrNode->getOp(), symbolTable,  type);
            }
            if (returnVal)
                return 0;
    
            return intermediate.addConstantUnion(unionArray, type, aggrNode->getLine());
        }
    
        return 0;
    }
    
    // Function for constructor implementation. Calls addUnaryMath with appropriate EOp value
    // for the parameter to the constructor (passed to this function). Essentially, it converts
    // the parameter types correctly. If a constructor expects an int (like ivec2) and is passed a 
    // float, then float is converted to int.
    //
    // Returns 0 for an error or the constructed node.
    //
    TIntermTyped* TParseContext::constructBuiltIn(const TType* type, TOperator op, TIntermNode* node, TSourceLoc line, bool subset)
    {
        TIntermTyped* newNode;
        TOperator basicOp;
    
        //
        // First, convert types as needed.
        //
        switch (op) {
        case EOpConstructVec2:
        case EOpConstructVec3:
        case EOpConstructVec4:
        case EOpConstructMat2:
        case EOpConstructMat3:
        case EOpConstructMat4:
        case EOpConstructFloat:
            basicOp = EOpConstructFloat;
            break;
    
        case EOpConstructIVec2:
        case EOpConstructIVec3:
        case EOpConstructIVec4:
        case EOpConstructInt:
            basicOp = EOpConstructInt;
            break;
    
        case EOpConstructBVec2:
        case EOpConstructBVec3:
        case EOpConstructBVec4:
        case EOpConstructBool:
            basicOp = EOpConstructBool;
            break;
    
        default:
            error(line, "unsupported construction", "", "");
            recover();
    
            return 0;
        }
        newNode = intermediate.addUnaryMath(basicOp, node, node->getLine(), symbolTable);
        if (newNode == 0) {
            error(line, "can't convert", "constructor", "");
            return 0;
        }
    
        //
        // Now, if there still isn't an operation to do the construction, and we need one, add one.
        //
        
        // Otherwise, skip out early.
        if (subset || (newNode != node && newNode->getType() == *type))
            return newNode;
    
        // setAggregateOperator will insert a new node for the constructor, as needed.
        return intermediate.setAggregateOperator(newNode, op, line);
    }
    
    // This function tests for the type of the parameters to the structures constructors. Raises
    // an error message if the expected type does not match the parameter passed to the constructor.
    //
    // Returns 0 for an error or the input node itself if the expected and the given parameter types match.
    //
    TIntermTyped* TParseContext::constructStruct(TIntermNode* node, TType* type, int paramCount, TSourceLoc line, bool subset)
    {
        if (*type == node->getAsTyped()->getType()) {
            if (subset)
                return node->getAsTyped();
            else
                return intermediate.setAggregateOperator(node->getAsTyped(), EOpConstructStruct, line);
        } else {
            error(line, "", "constructor", "cannot convert parameter %d from '%s' to '%s'", paramCount,
                    node->getAsTyped()->getType().getBasicString(), type->getBasicString());
            recover();
        }
    
        return 0;
    }
    
    //
    // This function returns the tree representation for the vector field(s) being accessed from contant vector.
    // If only one component of vector is accessed (v.x or v[0] where v is a contant vector), then a contant node is
    // returned, else an aggregate node is returned (for v.xy). The input to this function could either be the symbol
    // node or it could be the intermediate tree representation of accessing fields in a constant structure or column of 
    // a constant matrix.
    //
    TIntermTyped* TParseContext::addConstVectorNode(TVectorFields& fields, TIntermTyped* node, TSourceLoc line)
    {
        TIntermTyped* typedNode;
        TIntermConstantUnion* tempConstantNode = node->getAsConstantUnion();
    
        ConstantUnion *unionArray;
        if (tempConstantNode) {
            unionArray = tempConstantNode->getUnionArrayPointer();
    
            if (!unionArray) {  // this error message should never be raised
                infoSink.info.message(EPrefixInternalError, "ConstantUnion not initialized in addConstVectorNode function", line);
                recover();
    
                return node;
            }
        } else { // The node has to be either a symbol node or an aggregate node or a tempConstant node, else, its an error
            error(line, "Cannot offset into the vector", "Error", "");
            recover();
    
            return 0;
        }
    
        ConstantUnion* constArray = new ConstantUnion[fields.num];
    
        for (int i = 0; i < fields.num; i++) {
            if (fields.offsets[i] >= node->getType().getObjectSize()) {
                error(line, "", "[", "vector field selection out of range '%d'", fields.offsets[i]);
                recover();
                fields.offsets[i] = 0;
            }
            
            constArray[i] = unionArray[fields.offsets[i]];
    
        } 
        typedNode = intermediate.addConstantUnion(constArray, node->getType(), line);
        return typedNode;
    }
    
    //
    // This function returns the column being accessed from a constant matrix. The values are retrieved from
    // the symbol table and parse-tree is built for a vector (each column of a matrix is a vector). The input 
    // to the function could either be a symbol node (m[0] where m is a constant matrix)that represents a 
    // constant matrix or it could be the tree representation of the constant matrix (s.m1[0] where s is a constant structure)
    //
    TIntermTyped* TParseContext::addConstMatrixNode(int index, TIntermTyped* node, TSourceLoc line)
    {
        TIntermTyped* typedNode;
        TIntermConstantUnion* tempConstantNode = node->getAsConstantUnion();
    
        if (index >= node->getType().getNominalSize()) {
            error(line, "", "[", "matrix field selection out of range '%d'", index);
            recover();
            index = 0;
        }
    
        if (tempConstantNode) {
             ConstantUnion* unionArray = tempConstantNode->getUnionArrayPointer();
             int size = tempConstantNode->getType().getNominalSize();
             typedNode = intermediate.addConstantUnion(&unionArray[size*index], tempConstantNode->getType(), line);
        } else {
            error(line, "Cannot offset into the matrix", "Error", "");
            recover();
    
            return 0;
        }
    
        return typedNode;
    }
    
    
    //
    // This function returns an element of an array accessed from a constant array. The values are retrieved from
    // the symbol table and parse-tree is built for the type of the element. The input 
    // to the function could either be a symbol node (a[0] where a is a constant array)that represents a 
    // constant array or it could be the tree representation of the constant array (s.a1[0] where s is a constant structure)
    //
    TIntermTyped* TParseContext::addConstArrayNode(int index, TIntermTyped* node, TSourceLoc line)
    {
        TIntermTyped* typedNode;
        TIntermConstantUnion* tempConstantNode = node->getAsConstantUnion();
        TType arrayElementType = node->getType();
        arrayElementType.clearArrayness();
    
        if (index >= node->getType().getArraySize()) {
            error(line, "", "[", "array field selection out of range '%d'", index);
            recover();
            index = 0;
        }
    
        int arrayElementSize = arrayElementType.getObjectSize();
    
        if (tempConstantNode) {
             ConstantUnion* unionArray = tempConstantNode->getUnionArrayPointer();
             typedNode = intermediate.addConstantUnion(&unionArray[arrayElementSize * index], tempConstantNode->getType(), line);
        } else {
            error(line, "Cannot offset into the array", "Error", "");
            recover();
    
            return 0;
        }
    
        return typedNode;
    }
    
    
    //
    // 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(TString& identifier, TIntermTyped* node, TSourceLoc line)
    {
        const TTypeList* fields = node->getType().getStruct();
        TIntermTyped *typedNode;
        int instanceSize = 0;
        unsigned int index = 0;
        TIntermConstantUnion *tempConstantNode = node->getAsConstantUnion();
    
        for ( index = 0; index < fields->size(); ++index) {
            if ((*fields)[index].type->getFieldName() == identifier) {
                break;
            } else {
                instanceSize += (*fields)[index].type->getObjectSize();
            }
        }
    
        if (tempConstantNode) {
             ConstantUnion* constArray = tempConstantNode->getUnionArrayPointer();
    
             typedNode = intermediate.addConstantUnion(constArray+instanceSize, tempConstantNode->getType(), line); // type will be changed in the calling function
        } else {
            error(line, "Cannot offset into the structure", "Error", "");
            recover();
    
            return 0;
        }
    
        return typedNode;
    }
    
    OS_TLSIndex GlobalParseContextIndex = OS_INVALID_TLS_INDEX;
    
    bool InitializeParseContextIndex()
    {
        if (GlobalParseContextIndex != OS_INVALID_TLS_INDEX) {
            assert(0 && "InitializeParseContextIndex(): Parse Context already initalised");
            return false;
        }
    
        //
        // Allocate a TLS index.
        //
        GlobalParseContextIndex = OS_AllocTLSIndex();
        
        if (GlobalParseContextIndex == OS_INVALID_TLS_INDEX) {
            assert(0 && "InitializeParseContextIndex(): Parse Context already initalised");
            return false;
        }
    
        return true;
    }
    
    bool FreeParseContextIndex()
    {
        OS_TLSIndex tlsiIndex = GlobalParseContextIndex;
    
        if (GlobalParseContextIndex == OS_INVALID_TLS_INDEX) {
            assert(0 && "FreeParseContextIndex(): Parse Context index not initalised");
            return false;
        }
    
        GlobalParseContextIndex = OS_INVALID_TLS_INDEX;
    
        return OS_FreeTLSIndex(tlsiIndex);
    }
    
    bool InitializeGlobalParseContext()
    {
        if (GlobalParseContextIndex == OS_INVALID_TLS_INDEX) {
            assert(0 && "InitializeGlobalParseContext(): Parse Context index not initalised");
            return false;
        }
    
        TThreadParseContext *lpParseContext = static_cast<TThreadParseContext *>(OS_GetTLSValue(GlobalParseContextIndex));
        if (lpParseContext != 0) {
            assert(0 && "InitializeParseContextIndex(): Parse Context already initalised");
            return false;
        }
    
        TThreadParseContext *lpThreadData = new TThreadParseContext();
        if (lpThreadData == 0) {
            assert(0 && "InitializeGlobalParseContext(): Unable to create thread parse context");
            return false;
        }
    
        lpThreadData->lpGlobalParseContext = 0;
        OS_SetTLSValue(GlobalParseContextIndex, lpThreadData);
    
        return true;
    }
    
    bool FreeParseContext()
    {
        if (GlobalParseContextIndex == OS_INVALID_TLS_INDEX) {
            assert(0 && "FreeParseContext(): Parse Context index not initalised");
            return false;
        }
    
        TThreadParseContext *lpParseContext = static_cast<TThreadParseContext *>(OS_GetTLSValue(GlobalParseContextIndex));
        if (lpParseContext)
            delete lpParseContext;
    
        return true;
    }
    
    TParseContextPointer& GetGlobalParseContext()
    {
        //
        // Minimal error checking for speed
        //
    
        TThreadParseContext *lpParseContext = static_cast<TThreadParseContext *>(OS_GetTLSValue(GlobalParseContextIndex));
    
        return lpParseContext->lpGlobalParseContext;
    }