src/compiler/translator/OutputGLSLBase.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/OutputGLSLBase.h"
#include "compiler/translator/compilerdebug.h"

#include <cfloat>

namespace
{
TString arrayBrackets(const TType &type)
{
    ASSERT(type.isArray());
    TInfoSinkBase out;
    out << "[" << type.getArraySize() << "]";
    return TString(out.c_str());
}

bool isSingleStatement(TIntermNode *node)
{
    if (const TIntermAggregate *aggregate = node->getAsAggregate())
    {
        return (aggregate->getOp() != EOpFunction) &&
               (aggregate->getOp() != EOpSequence);
    }
    else if (const TIntermSelection *selection = node->getAsSelectionNode())
    {
        // Ternary operators are usually part of an assignment operator.
        // This handles those rare cases in which they are all by themselves.
        return selection->usesTernaryOperator();
    }
    else if (node->getAsLoopNode())
    {
        return false;
    }
    return true;
}
}  // namespace

TOutputGLSLBase::TOutputGLSLBase(TInfoSinkBase &objSink,
                                 ShArrayIndexClampingStrategy clampingStrategy,
                                 ShHashFunction64 hashFunction,
                                 NameMap &nameMap,
                                 TSymbolTable &symbolTable,
                                 int shaderVersion)
    : TIntermTraverser(true, true, true),
      mObjSink(objSink),
      mDeclaringVariables(false),
      mClampingStrategy(clampingStrategy),
      mHashFunction(hashFunction),
      mNameMap(nameMap),
      mSymbolTable(symbolTable),
      mShaderVersion(shaderVersion)
{
}

void TOutputGLSLBase::writeTriplet(
    Visit visit, const char *preStr, const char *inStr, const char *postStr)
{
    TInfoSinkBase &out = objSink();
    if (visit == PreVisit && preStr)
        out << preStr;
    else if (visit == InVisit && inStr)
        out << inStr;
    else if (visit == PostVisit && postStr)
        out << postStr;
}

void TOutputGLSLBase::writeBuiltInFunctionTriplet(
    Visit visit, const char *preStr, bool useEmulatedFunction)
{
    TString preString = useEmulatedFunction ?
        BuiltInFunctionEmulator::GetEmulatedFunctionName(preStr) : preStr;
    writeTriplet(visit, preString.c_str(), ", ", ")");
}

void TOutputGLSLBase::writeVariableType(const TType &type)
{
    TInfoSinkBase &out = objSink();
    TQualifier qualifier = type.getQualifier();
    if (qualifier != EvqTemporary && qualifier != EvqGlobal)
    {
        out << type.getQualifierString() << " ";
    }
    // Declare the struct if we have not done so already.
    if (type.getBasicType() == EbtStruct && !structDeclared(type.getStruct()))
    {
        TStructure *structure = type.getStruct();

        declareStruct(structure);

        if (!structure->name().empty())
        {
            mDeclaredStructs.insert(structure->uniqueId());
        }
    }
    else
    {
        if (writeVariablePrecision(type.getPrecision()))
            out << " ";
        out << getTypeName(type);
    }
}

void TOutputGLSLBase::writeFunctionParameters(const TIntermSequence &args)
{
    TInfoSinkBase &out = objSink();
    for (TIntermSequence::const_iterator iter = args.begin();
         iter != args.end(); ++iter)
    {
        const TIntermSymbol *arg = (*iter)->getAsSymbolNode();
        ASSERT(arg != NULL);

        const TType &type = arg->getType();
        writeVariableType(type);

        const TString &name = arg->getSymbol();
        if (!name.empty())
            out << " " << hashName(name);
        if (type.isArray())
            out << arrayBrackets(type);

        // Put a comma if this is not the last argument.
        if (iter != args.end() - 1)
            out << ", ";
    }
}

const ConstantUnion *TOutputGLSLBase::writeConstantUnion(
    const TType &type, const ConstantUnion *pConstUnion)
{
    TInfoSinkBase &out = objSink();

    if (type.getBasicType() == EbtStruct)
    {
        const TStructure *structure = type.getStruct();
        out << hashName(structure->name()) << "(";

        const TFieldList &fields = structure->fields();
        for (size_t i = 0; i < fields.size(); ++i)
        {
            const TType *fieldType = fields[i]->type();
            ASSERT(fieldType != NULL);
            pConstUnion = writeConstantUnion(*fieldType, pConstUnion);
            if (i != fields.size() - 1)
                out << ", ";
        }
        out << ")";
    }
    else
    {
        size_t size = type.getObjectSize();
        bool writeType = size > 1;
        if (writeType)
            out << getTypeName(type) << "(";
        for (size_t i = 0; i < size; ++i, ++pConstUnion)
        {
            switch (pConstUnion->getType())
            {
              case EbtFloat:
                out << std::min(FLT_MAX, std::max(-FLT_MAX, pConstUnion->getFConst()));
                break;
              case EbtInt:
                out << pConstUnion->getIConst();
                break;
              case EbtBool:
                out << pConstUnion->getBConst();
                break;
              default: UNREACHABLE();
            }
            if (i != size - 1)
                out << ", ";
        }
        if (writeType)
            out << ")";
    }
    return pConstUnion;
}

void TOutputGLSLBase::visitSymbol(TIntermSymbol *node)
{
    TInfoSinkBase &out = objSink();
    if (mLoopUnrollStack.needsToReplaceSymbolWithValue(node))
        out << mLoopUnrollStack.getLoopIndexValue(node);
    else
        out << hashVariableName(node->getSymbol());

    if (mDeclaringVariables && node->getType().isArray())
        out << arrayBrackets(node->getType());
}

void TOutputGLSLBase::visitConstantUnion(TIntermConstantUnion *node)
{
    writeConstantUnion(node->getType(), node->getUnionArrayPointer());
}

bool TOutputGLSLBase::visitBinary(Visit visit, TIntermBinary *node)
{
    bool visitChildren = true;
    TInfoSinkBase &out = objSink();
    switch (node->getOp())
    {
      case EOpInitialize:
        if (visit == InVisit)
        {
            out << " = ";
            // RHS of initialize is not being declared.
            mDeclaringVariables = false;
        }
        break;
      case EOpAssign:
        writeTriplet(visit, "(", " = ", ")");
        break;
      case EOpAddAssign:
        writeTriplet(visit, "(", " += ", ")");
        break;
      case EOpSubAssign:
        writeTriplet(visit, "(", " -= ", ")");
        break;
      case EOpDivAssign:
        writeTriplet(visit, "(", " /= ", ")");
        break;
      case EOpIModAssign:
        writeTriplet(visit, "(", " %= ", ")");
        break;
      // Notice the fall-through.
      case EOpMulAssign:
      case EOpVectorTimesMatrixAssign:
      case EOpVectorTimesScalarAssign:
      case EOpMatrixTimesScalarAssign:
      case EOpMatrixTimesMatrixAssign:
        writeTriplet(visit, "(", " *= ", ")");
        break;
      case EOpBitShiftLeftAssign:
        writeTriplet(visit, "(", " <<= ", ")");
        break;
      case EOpBitShiftRightAssign:
        writeTriplet(visit, "(", " >>= ", ")");
        break;
      case EOpBitwiseAndAssign:
        writeTriplet(visit, "(", " &= ", ")");
        break;
      case EOpBitwiseXorAssign:
        writeTriplet(visit, "(", " ^= ", ")");
        break;
      case EOpBitwiseOrAssign:
        writeTriplet(visit, "(", " |= ", ")");
        break;

      case EOpIndexDirect:
        writeTriplet(visit, NULL, "[", "]");
        break;
      case EOpIndexIndirect:
        if (node->getAddIndexClamp())
        {
            if (visit == InVisit)
            {
                if (mClampingStrategy == SH_CLAMP_WITH_CLAMP_INTRINSIC)
                    out << "[int(clamp(float(";
                else
                    out << "[webgl_int_clamp(";
            }
            else if (visit == PostVisit)
            {
                int maxSize;
                TIntermTyped *left = node->getLeft();
                TType leftType = left->getType();

                if (left->isArray())
                {
                    // The shader will fail validation if the array length is not > 0.
                    maxSize = leftType.getArraySize() - 1;
                }
                else
                {
                    maxSize = leftType.getNominalSize() - 1;
                }

                if (mClampingStrategy == SH_CLAMP_WITH_CLAMP_INTRINSIC)
                    out << "), 0.0, float(" << maxSize << ")))]";
                else
                    out << ", 0, " << maxSize << ")]";
            }
        }
        else
        {
            writeTriplet(visit, NULL, "[", "]");
        }
        break;
      case EOpIndexDirectStruct:
        if (visit == InVisit)
        {
            // Here we are writing out "foo.bar", where "foo" is struct
            // and "bar" is field. In AST, it is represented as a binary
            // node, where left child represents "foo" and right child "bar".
            // The node itself represents ".". The struct field "bar" is
            // actually stored as an index into TStructure::fields.
            out << ".";
            const TStructure *structure = node->getLeft()->getType().getStruct();
            const TIntermConstantUnion *index = node->getRight()->getAsConstantUnion();
            const TField *field = structure->fields()[index->getIConst(0)];

            TString fieldName = field->name();
            if (!mSymbolTable.findBuiltIn(structure->name(), mShaderVersion))
                fieldName = hashName(fieldName);

            out << fieldName;
            visitChildren = false;
        }
        break;
      case EOpVectorSwizzle:
        if (visit == InVisit)
        {
            out << ".";
            TIntermAggregate *rightChild = node->getRight()->getAsAggregate();
            TIntermSequence *sequence = rightChild->getSequence();
            for (TIntermSequence::iterator sit = sequence->begin(); sit != sequence->end(); ++sit)
            {
                TIntermConstantUnion *element = (*sit)->getAsConstantUnion();
                ASSERT(element->getBasicType() == EbtInt);
                ASSERT(element->getNominalSize() == 1);
                const ConstantUnion& data = element->getUnionArrayPointer()[0];
                ASSERT(data.getType() == EbtInt);
                switch (data.getIConst())
                {
                  case 0:
                    out << "x";
                    break;
                  case 1:
                    out << "y";
                    break;
                  case 2:
                    out << "z";
                    break;
                  case 3:
                    out << "w";
                    break;
                  default:
                    UNREACHABLE();
                }
            }
            visitChildren = false;
        }
        break;

      case EOpAdd:
        writeTriplet(visit, "(", " + ", ")");
        break;
      case EOpSub:
        writeTriplet(visit, "(", " - ", ")");
        break;
      case EOpMul:
        writeTriplet(visit, "(", " * ", ")");
        break;
      case EOpDiv:
        writeTriplet(visit, "(", " / ", ")");
        break;
      case EOpIMod:
        writeTriplet(visit, "(", " % ", ")");
        break;
      case EOpBitShiftLeft:
        writeTriplet(visit, "(", " << ", ")");
        break;
      case EOpBitShiftRight:
        writeTriplet(visit, "(", " >> ", ")");
        break;
      case EOpBitwiseAnd:
        writeTriplet(visit, "(", " & ", ")");
        break;
      case EOpBitwiseXor:
        writeTriplet(visit, "(", " ^ ", ")");
        break;
      case EOpBitwiseOr:
        writeTriplet(visit, "(", " | ", ")");
        break;

      case EOpEqual:
        writeTriplet(visit, "(", " == ", ")");
        break;
      case EOpNotEqual:
        writeTriplet(visit, "(", " != ", ")");
        break;
      case EOpLessThan:
        writeTriplet(visit, "(", " < ", ")");
        break;
      case EOpGreaterThan:
        writeTriplet(visit, "(", " > ", ")");
        break;
      case EOpLessThanEqual:
        writeTriplet(visit, "(", " <= ", ")");
        break;
      case EOpGreaterThanEqual:
        writeTriplet(visit, "(", " >= ", ")");
        break;

      // Notice the fall-through.
      case EOpVectorTimesScalar:
      case EOpVectorTimesMatrix:
      case EOpMatrixTimesVector:
      case EOpMatrixTimesScalar:
      case EOpMatrixTimesMatrix:
        writeTriplet(visit, "(", " * ", ")");
        break;

      case EOpLogicalOr:
        writeTriplet(visit, "(", " || ", ")");
        break;
      case EOpLogicalXor:
        writeTriplet(visit, "(", " ^^ ", ")");
        break;
      case EOpLogicalAnd:
        writeTriplet(visit, "(", " && ", ")");
        break;
      default:
        UNREACHABLE();
    }

    return visitChildren;
}

bool TOutputGLSLBase::visitUnary(Visit visit, TIntermUnary *node)
{
    TString preString;
    TString postString = ")";

    switch (node->getOp())
    {
      case EOpNegative: preString = "(-"; break;
      case EOpPositive: preString = "(+"; break;
      case EOpVectorLogicalNot: preString = "not("; break;
      case EOpLogicalNot: preString = "(!"; break;
      case EOpBitwiseNot: preString = "(~"; break;

      case EOpPostIncrement: preString = "("; postString = "++)"; break;
      case EOpPostDecrement: preString = "("; postString = "--)"; break;
      case EOpPreIncrement: preString = "(++"; break;
      case EOpPreDecrement: preString = "(--"; break;

      case EOpRadians:
        preString = "radians(";
        break;
      case EOpDegrees:
        preString = "degrees(";
        break;
      case EOpSin:
        preString = "sin(";
        break;
      case EOpCos:
        preString = "cos(";
        break;
      case EOpTan:
        preString = "tan(";
        break;
      case EOpAsin:
        preString = "asin(";
        break;
      case EOpAcos:
        preString = "acos(";
        break;
      case EOpAtan:
        preString = "atan(";
        break;

      case EOpSinh:
        preString = "sinh(";
        break;
      case EOpCosh:
        preString = "cosh(";
        break;
      case EOpTanh:
        preString = "tanh(";
        break;
      case EOpAsinh:
        preString = "asinh(";
        break;
      case EOpAcosh:
        preString = "acosh(";
        break;
      case EOpAtanh:
        preString = "atanh(";
        break;

      case EOpExp:
        preString = "exp(";
        break;
      case EOpLog:
        preString = "log(";
        break;
      case EOpExp2:
        preString = "exp2(";
        break;
      case EOpLog2:
        preString = "log2(";
        break;
      case EOpSqrt:
        preString = "sqrt(";
        break;
      case EOpInverseSqrt:
        preString = "inversesqrt(";
        break;

      case EOpAbs:
        preString = "abs(";
        break;
      case EOpSign:
        preString = "sign(";
        break;
      case EOpFloor:
        preString = "floor(";
        break;
      case EOpCeil:
        preString = "ceil(";
        break;
      case EOpFract:
        preString = "fract(";
        break;
      case EOpIsNan:
        preString = "isnan(";
        break;
      case EOpIsInf:
        preString = "isinf(";
        break;

      case EOpFloatBitsToInt:
        preString = "floatBitsToInt(";
        break;
      case EOpFloatBitsToUint:
        preString = "floatBitsToUint(";
        break;
      case EOpIntBitsToFloat:
        preString = "intBitsToFloat(";
        break;
      case EOpUintBitsToFloat:
        preString = "uintBitsToFloat(";
        break;

      case EOpPackSnorm2x16:
        preString = "packSnorm2x16(";
        break;
      case EOpPackUnorm2x16:
        preString = "packUnorm2x16(";
        break;
      case EOpPackHalf2x16:
        preString = "packHalf2x16(";
        break;
      case EOpUnpackSnorm2x16:
        preString = "unpackSnorm2x16(";
        break;
      case EOpUnpackUnorm2x16:
        preString = "unpackUnorm2x16(";
        break;
      case EOpUnpackHalf2x16:
        preString = "unpackHalf2x16(";
        break;

      case EOpLength:
        preString = "length(";
        break;
      case EOpNormalize:
        preString = "normalize(";
        break;

      case EOpDFdx:
        preString = "dFdx(";
        break;
      case EOpDFdy:
        preString = "dFdy(";
        break;
      case EOpFwidth:
        preString = "fwidth(";
        break;

      case EOpTranspose:
        preString = "transpose(";
        break;
      case EOpDeterminant:
        preString = "determinant(";
        break;
      case EOpInverse:
        preString = "inverse(";
        break;

      case EOpAny:
        preString = "any(";
        break;
      case EOpAll:
        preString = "all(";
        break;

      default:
        UNREACHABLE();
    }

    if (visit == PreVisit && node->getUseEmulatedFunction())
        preString = BuiltInFunctionEmulator::GetEmulatedFunctionName(preString);
    writeTriplet(visit, preString.c_str(), NULL, postString.c_str());

    return true;
}

bool TOutputGLSLBase::visitSelection(Visit visit, TIntermSelection *node)
{
    TInfoSinkBase &out = objSink();

    if (node->usesTernaryOperator())
    {
        // Notice two brackets at the beginning and end. The outer ones
        // encapsulate the whole ternary expression. This preserves the
        // order of precedence when ternary expressions are used in a
        // compound expression, i.e., c = 2 * (a < b ? 1 : 2).
        out << "((";
        node->getCondition()->traverse(this);
        out << ") ? (";
        node->getTrueBlock()->traverse(this);
        out << ") : (";
        node->getFalseBlock()->traverse(this);
        out << "))";
    }
    else
    {
        out << "if (";
        node->getCondition()->traverse(this);
        out << ")\n";

        incrementDepth(node);
        visitCodeBlock(node->getTrueBlock());

        if (node->getFalseBlock())
        {
            out << "else\n";
            visitCodeBlock(node->getFalseBlock());
        }
        decrementDepth();
    }
    return false;
}

bool TOutputGLSLBase::visitSwitch(Visit, TIntermSwitch *)
{
    UNIMPLEMENTED();
    return false;
}

bool TOutputGLSLBase::visitCase(Visit, TIntermCase *)
{
    UNIMPLEMENTED();
    return false;
}

bool TOutputGLSLBase::visitAggregate(Visit visit, TIntermAggregate *node)
{
    bool visitChildren = true;
    TInfoSinkBase &out = objSink();
    TString preString;
    bool useEmulatedFunction = (visit == PreVisit && node->getUseEmulatedFunction());
    switch (node->getOp())
    {
      case EOpSequence:
        // Scope the sequences except when at the global scope.
        if (mDepth > 0)
        {
            out << "{\n";
        }

        incrementDepth(node);
        for (TIntermSequence::const_iterator iter = node->getSequence()->begin();
             iter != node->getSequence()->end(); ++iter)
        {
            TIntermNode *curNode = *iter;
            ASSERT(curNode != NULL);
            curNode->traverse(this);

            if (isSingleStatement(curNode))
                out << ";\n";
        }
        decrementDepth();

        // Scope the sequences except when at the global scope.
        if (mDepth > 0)
        {
            out << "}\n";
        }
        visitChildren = false;
        break;
      case EOpPrototype:
        // Function declaration.
        ASSERT(visit == PreVisit);
        writeVariableType(node->getType());
        out << " " << hashFunctionName(node->getName());

        out << "(";
        writeFunctionParameters(*(node->getSequence()));
        out << ")";

        visitChildren = false;
        break;
      case EOpFunction: {
        // Function definition.
        ASSERT(visit == PreVisit);
        writeVariableType(node->getType());
        out << " " << hashFunctionName(node->getName());

        incrementDepth(node);
        // Function definition node contains one or two children nodes
        // representing function parameters and function body. The latter
        // is not present in case of empty function bodies.
        const TIntermSequence &sequence = *(node->getSequence());
        ASSERT((sequence.size() == 1) || (sequence.size() == 2));
        TIntermSequence::const_iterator seqIter = sequence.begin();

        // Traverse function parameters.
        TIntermAggregate *params = (*seqIter)->getAsAggregate();
        ASSERT(params != NULL);
        ASSERT(params->getOp() == EOpParameters);
        params->traverse(this);

        // Traverse function body.
        TIntermAggregate *body = ++seqIter != sequence.end() ?
            (*seqIter)->getAsAggregate() : NULL;
        visitCodeBlock(body);
        decrementDepth();

        // Fully processed; no need to visit children.
        visitChildren = false;
        break;
      }
      case EOpFunctionCall:
        // Function call.
        if (visit == PreVisit)
            out << hashFunctionName(node->getName()) << "(";
        else if (visit == InVisit)
            out << ", ";
        else
            out << ")";
        break;
      case EOpInternalFunctionCall:
        // Function call to an internal helper function.
        if (visit == PreVisit)
            out << node->getName() << "(";
        else if (visit == InVisit)
            out << ", ";
        else
            out << ")";
        break;
      case EOpParameters:
        // Function parameters.
        ASSERT(visit == PreVisit);
        out << "(";
        writeFunctionParameters(*(node->getSequence()));
        out << ")";
        visitChildren = false;
        break;
      case EOpDeclaration:
        // Variable declaration.
        if (visit == PreVisit)
        {
            const TIntermSequence &sequence = *(node->getSequence());
            const TIntermTyped *variable = sequence.front()->getAsTyped();
            writeVariableType(variable->getType());
            out << " ";
            mDeclaringVariables = true;
        }
        else if (visit == InVisit)
        {
            out << ", ";
            mDeclaringVariables = true;
        }
        else
        {
            mDeclaringVariables = false;
        }
        break;
      case EOpInvariantDeclaration:
        // Invariant declaration.
        ASSERT(visit == PreVisit);
        {
            const TIntermSequence *sequence = node->getSequence();
            ASSERT(sequence && sequence->size() == 1);
            const TIntermSymbol *symbol = sequence->front()->getAsSymbolNode();
            ASSERT(symbol);
            out << "invariant " << hashVariableName(symbol->getSymbol());
        }
        visitChildren = false;
        break;
      case EOpConstructFloat:
        writeTriplet(visit, "float(", NULL, ")");
        break;
      case EOpConstructVec2:
        writeBuiltInFunctionTriplet(visit, "vec2(", false);
        break;
      case EOpConstructVec3:
        writeBuiltInFunctionTriplet(visit, "vec3(", false);
        break;
      case EOpConstructVec4:
        writeBuiltInFunctionTriplet(visit, "vec4(", false);
        break;
      case EOpConstructBool:
        writeTriplet(visit, "bool(", NULL, ")");
        break;
      case EOpConstructBVec2:
        writeBuiltInFunctionTriplet(visit, "bvec2(", false);
        break;
      case EOpConstructBVec3:
        writeBuiltInFunctionTriplet(visit, "bvec3(", false);
        break;
      case EOpConstructBVec4:
        writeBuiltInFunctionTriplet(visit, "bvec4(", false);
        break;
      case EOpConstructInt:
        writeTriplet(visit, "int(", NULL, ")");
        break;
      case EOpConstructIVec2:
        writeBuiltInFunctionTriplet(visit, "ivec2(", false);
        break;
      case EOpConstructIVec3:
        writeBuiltInFunctionTriplet(visit, "ivec3(", false);
        break;
      case EOpConstructIVec4:
        writeBuiltInFunctionTriplet(visit, "ivec4(", false);
        break;
      case EOpConstructMat2:
        writeBuiltInFunctionTriplet(visit, "mat2(", false);
        break;
      case EOpConstructMat3:
        writeBuiltInFunctionTriplet(visit, "mat3(", false);
        break;
      case EOpConstructMat4:
        writeBuiltInFunctionTriplet(visit, "mat4(", false);
        break;
      case EOpConstructStruct:
        if (visit == PreVisit)
        {
            const TType &type = node->getType();
            ASSERT(type.getBasicType() == EbtStruct);
            out << hashName(type.getStruct()->name()) << "(";
        }
        else if (visit == InVisit)
        {
            out << ", ";
        }
        else
        {
            out << ")";
        }
        break;

      case EOpOuterProduct:
        writeBuiltInFunctionTriplet(visit, "outerProduct(", useEmulatedFunction);
        break;

      case EOpLessThan:
        writeBuiltInFunctionTriplet(visit, "lessThan(", useEmulatedFunction);
        break;
      case EOpGreaterThan:
        writeBuiltInFunctionTriplet(visit, "greaterThan(", useEmulatedFunction);
        break;
      case EOpLessThanEqual:
        writeBuiltInFunctionTriplet(visit, "lessThanEqual(", useEmulatedFunction);
        break;
      case EOpGreaterThanEqual:
        writeBuiltInFunctionTriplet(visit, "greaterThanEqual(", useEmulatedFunction);
        break;
      case EOpVectorEqual:
        writeBuiltInFunctionTriplet(visit, "equal(", useEmulatedFunction);
        break;
      case EOpVectorNotEqual:
        writeBuiltInFunctionTriplet(visit, "notEqual(", useEmulatedFunction);
        break;
      case EOpComma:
        writeTriplet(visit, "(", ", ", ")");
        break;

      case EOpMod:
        writeBuiltInFunctionTriplet(visit, "mod(", useEmulatedFunction);
        break;
      case EOpModf:
        writeBuiltInFunctionTriplet(visit, "modf(", useEmulatedFunction);
        break;
      case EOpPow:
        writeBuiltInFunctionTriplet(visit, "pow(", useEmulatedFunction);
        break;
      case EOpAtan:
        writeBuiltInFunctionTriplet(visit, "atan(", useEmulatedFunction);
        break;
      case EOpMin:
        writeBuiltInFunctionTriplet(visit, "min(", useEmulatedFunction);
        break;
      case EOpMax:
        writeBuiltInFunctionTriplet(visit, "max(", useEmulatedFunction);
        break;
      case EOpClamp:
        writeBuiltInFunctionTriplet(visit, "clamp(", useEmulatedFunction);
        break;
      case EOpMix:
        writeBuiltInFunctionTriplet(visit, "mix(", useEmulatedFunction);
        break;
      case EOpStep:
        writeBuiltInFunctionTriplet(visit, "step(", useEmulatedFunction);
        break;
      case EOpSmoothStep:
        writeBuiltInFunctionTriplet(visit, "smoothstep(", useEmulatedFunction);
        break;
      case EOpDistance:
        writeBuiltInFunctionTriplet(visit, "distance(", useEmulatedFunction);
        break;
      case EOpDot:
        writeBuiltInFunctionTriplet(visit, "dot(", useEmulatedFunction);
        break;
      case EOpCross:
        writeBuiltInFunctionTriplet(visit, "cross(", useEmulatedFunction);
        break;
      case EOpFaceForward:
        writeBuiltInFunctionTriplet(visit, "faceforward(", useEmulatedFunction);
        break;
      case EOpReflect:
        writeBuiltInFunctionTriplet(visit, "reflect(", useEmulatedFunction);
        break;
      case EOpRefract:
        writeBuiltInFunctionTriplet(visit, "refract(", useEmulatedFunction);
        break;
      case EOpMul:
        writeBuiltInFunctionTriplet(visit, "matrixCompMult(", useEmulatedFunction);
        break;

      default:
        UNREACHABLE();
    }
    return visitChildren;
}

bool TOutputGLSLBase::visitLoop(Visit visit, TIntermLoop *node)
{
    TInfoSinkBase &out = objSink();

    incrementDepth(node);
    // Loop header.
    TLoopType loopType = node->getType();
    if (loopType == ELoopFor)  // for loop
    {
        if (!node->getUnrollFlag())
        {
            out << "for (";
            if (node->getInit())
                node->getInit()->traverse(this);
            out << "; ";

            if (node->getCondition())
                node->getCondition()->traverse(this);
            out << "; ";

            if (node->getExpression())
                node->getExpression()->traverse(this);
            out << ")\n";
        }
        else
        {
            // Need to put a one-iteration loop here to handle break.
            TIntermSequence *declSeq =
                node->getInit()->getAsAggregate()->getSequence();
            TIntermSymbol *indexSymbol =
                (*declSeq)[0]->getAsBinaryNode()->getLeft()->getAsSymbolNode();
            TString name = hashVariableName(indexSymbol->getSymbol());
            out << "for (int " << name << " = 0; "
                << name << " < 1; "
                << "++" << name << ")\n";
        }
    }
    else if (loopType == ELoopWhile)  // while loop
    {
        out << "while (";
        ASSERT(node->getCondition() != NULL);
        node->getCondition()->traverse(this);
        out << ")\n";
    }
    else  // do-while loop
    {
        ASSERT(loopType == ELoopDoWhile);
        out << "do\n";
    }

    // Loop body.
    if (node->getUnrollFlag())
    {
        out << "{\n";
        mLoopUnrollStack.push(node);
        while (mLoopUnrollStack.satisfiesLoopCondition())
        {
            visitCodeBlock(node->getBody());
            mLoopUnrollStack.step();
        }
        mLoopUnrollStack.pop();
        out << "}\n";
    }
    else
    {
        visitCodeBlock(node->getBody());
    }

    // Loop footer.
    if (loopType == ELoopDoWhile)  // do-while loop
    {
        out << "while (";
        ASSERT(node->getCondition() != NULL);
        node->getCondition()->traverse(this);
        out << ");\n";
    }
    decrementDepth();

    // No need to visit children. They have been already processed in
    // this function.
    return false;
}

bool TOutputGLSLBase::visitBranch(Visit visit, TIntermBranch *node)
{
    switch (node->getFlowOp())
    {
      case EOpKill:
        writeTriplet(visit, "discard", NULL, NULL);
        break;
      case EOpBreak:
        writeTriplet(visit, "break", NULL, NULL);
        break;
      case EOpContinue:
        writeTriplet(visit, "continue", NULL, NULL);
        break;
      case EOpReturn:
        writeTriplet(visit, "return ", NULL, NULL);
        break;
      default:
        UNREACHABLE();
    }

    return true;
}

void TOutputGLSLBase::visitCodeBlock(TIntermNode *node)
{
    TInfoSinkBase &out = objSink();
    if (node != NULL)
    {
        node->traverse(this);
        // Single statements not part of a sequence need to be terminated
        // with semi-colon.
        if (isSingleStatement(node))
            out << ";\n";
    }
    else
    {
        out << "{\n}\n";  // Empty code block.
    }
}

TString TOutputGLSLBase::getTypeName(const TType &type)
{
    TInfoSinkBase out;
    if (type.isMatrix())
    {
        out << "mat";
        out << type.getNominalSize();
    }
    else if (type.isVector())
    {
        switch (type.getBasicType())
        {
          case EbtFloat:
            out << "vec";
            break;
          case EbtInt:
            out << "ivec";
            break;
          case EbtBool:
            out << "bvec";
            break;
          default:
            UNREACHABLE();
        }
        out << type.getNominalSize();
    }
    else
    {
        if (type.getBasicType() == EbtStruct)
            out << hashName(type.getStruct()->name());
        else
            out << type.getBasicString();
    }
    return TString(out.c_str());
}

TString TOutputGLSLBase::hashName(const TString &name)
{
    if (mHashFunction == NULL || name.empty())
        return name;
    NameMap::const_iterator it = mNameMap.find(name.c_str());
    if (it != mNameMap.end())
        return it->second.c_str();
    TString hashedName = TIntermTraverser::hash(name, mHashFunction);
    mNameMap[name.c_str()] = hashedName.c_str();
    return hashedName;
}

TString TOutputGLSLBase::hashVariableName(const TString &name)
{
    if (mSymbolTable.findBuiltIn(name, mShaderVersion) != NULL)
        return name;
    return hashName(name);
}

TString TOutputGLSLBase::hashFunctionName(const TString &mangled_name)
{
    TString name = TFunction::unmangleName(mangled_name);
    if (mSymbolTable.findBuiltIn(mangled_name, mShaderVersion) != NULL || name == "main")
        return translateTextureFunction(name);
    return hashName(name);
}

bool TOutputGLSLBase::structDeclared(const TStructure *structure) const
{
    ASSERT(structure);
    if (structure->name().empty())
    {
        return false;
    }

    return (mDeclaredStructs.count(structure->uniqueId()) > 0);
}

void TOutputGLSLBase::declareStruct(const TStructure *structure)
{
    TInfoSinkBase &out = objSink();

    out << "struct " << hashName(structure->name()) << "{\n";
    const TFieldList &fields = structure->fields();
    for (size_t i = 0; i < fields.size(); ++i)
    {
        const TField *field = fields[i];
        if (writeVariablePrecision(field->type()->getPrecision()))
            out << " ";
        out << getTypeName(*field->type()) << " " << hashName(field->name());
        if (field->type()->isArray())
            out << arrayBrackets(*field->type());
        out << ";\n";
    }
    out << "}";
}