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 "common/debug.h"

#include <cfloat>

namespace sh
{

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

bool isSingleStatement(TIntermNode *node)
{
    if (node->getAsFunctionDefinition())
    {
        return false;
    }
    else if (node->getAsBlock())
    {
        return false;
    }
    else if (node->getAsIfElseNode())
    {
        return false;
    }
    else if (node->getAsLoopNode())
    {
        return false;
    }
    else if (node->getAsSwitchNode())
    {
        return false;
    }
    else if (node->getAsCaseNode())
    {
        return false;
    }
    return true;
}

// If SH_SCALARIZE_VEC_AND_MAT_CONSTRUCTOR_ARGS is enabled, layout qualifiers are spilled whenever
// variables with specified layout qualifiers are copied. Additional checks are needed against the
// type and storage qualifier of the variable to verify that layout qualifiers have to be outputted.
// TODO (mradev): Fix layout qualifier spilling in ScalarizeVecAndMatConstructorArgs and remove
// NeedsToWriteLayoutQualifier.
bool NeedsToWriteLayoutQualifier(const TType &type)
{
    if (type.getBasicType() == EbtInterfaceBlock)
    {
        return false;
    }

    const TLayoutQualifier &layoutQualifier = type.getLayoutQualifier();

    if ((type.getQualifier() == EvqFragmentOut || type.getQualifier() == EvqVertexIn) &&
        layoutQualifier.location >= 0)
    {
        return true;
    }
    if (IsImage(type.getBasicType()) && layoutQualifier.imageInternalFormat != EiifUnspecified)
    {
        return true;
    }
    return false;
}

}  // namespace

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

void TOutputGLSLBase::writeInvariantQualifier(const TType &type)
{
    bool removeInvariant = ((type.getQualifier() == EvqVaryingIn && sh::IsGLSL420OrNewer(mOutput) &&
                             !(mCompileOptions & SH_DONT_REMOVE_INVARIANT_FOR_FRAGMENT_INPUT)) ||
                            (sh::IsGLSL410OrOlder(mOutput) && mShaderVersion >= 300 &&
                             !!(mCompileOptions & SH_REMOVE_INVARIANT_FOR_ESSL3)));
    if (!removeInvariant)
    {
        TInfoSinkBase &out = objSink();
        out << "invariant ";
    }
}

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::writeLayoutQualifier(const TType &type)
{
    if (!NeedsToWriteLayoutQualifier(type))
    {
        return;
    }

    TInfoSinkBase &out                      = objSink();
    const TLayoutQualifier &layoutQualifier = type.getLayoutQualifier();
    out << "layout(";

    if (type.getQualifier() == EvqFragmentOut || type.getQualifier() == EvqVertexIn)
    {
        if (layoutQualifier.location >= 0)
        {
            out << "location = " << layoutQualifier.location;
        }
    }

    if (IsImage(type.getBasicType()) && layoutQualifier.imageInternalFormat != EiifUnspecified)
    {
        ASSERT(type.getQualifier() == EvqTemporary || type.getQualifier() == EvqUniform);
        out << getImageInternalFormatString(layoutQualifier.imageInternalFormat);
    }

    out << ") ";
}

const char *TOutputGLSLBase::mapQualifierToString(TQualifier qualifier)
{
    if (sh::IsGLSL410OrOlder(mOutput) && mShaderVersion >= 300 &&
        !!(mCompileOptions & SH_REMOVE_CENTROID_FOR_ESSL3))
    {
        switch (qualifier)
        {
            // The return string is consistent with sh::getQualifierString() from
            // BaseTypes.h minus the "centroid" keyword.
            case EvqCentroid:
                return "";
            case EvqCentroidIn:
                return "smooth in";
            case EvqCentroidOut:
                return "smooth out";
            default:
                break;
        }
    }
    if (sh::IsGLSL130OrNewer(mOutput))
    {
        switch (qualifier)
        {
            case EvqAttribute:
                return "in";
            case EvqVaryingIn:
                return "in";
            case EvqVaryingOut:
                return "out";
            default:
                break;
        }
    }
    return sh::getQualifierString(qualifier);
}

void TOutputGLSLBase::writeVariableType(const TType &type)
{
    TQualifier qualifier = type.getQualifier();
    TInfoSinkBase &out = objSink();
    if (type.isInvariant())
    {
        writeInvariantQualifier(type);
    }
    if (type.getBasicType() == EbtInterfaceBlock)
    {
        TInterfaceBlock *interfaceBlock = type.getInterfaceBlock();
        declareInterfaceBlockLayout(interfaceBlock);
    }
    if (qualifier != EvqTemporary && qualifier != EvqGlobal)
    {
        const char *qualifierString = mapQualifierToString(qualifier);
        if (qualifierString && qualifierString[0] != '\0')
        {
            out << qualifierString << " ";
        }
    }

    const TMemoryQualifier &memoryQualifier = type.getMemoryQualifier();
    if (memoryQualifier.readonly)
    {
        ASSERT(IsImage(type.getBasicType()));
        out << "readonly ";
    }

    if (memoryQualifier.writeonly)
    {
        ASSERT(IsImage(type.getBasicType()));
        out << "writeonly ";
    }

    // 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 (type.getBasicType() == EbtInterfaceBlock)
    {
        TInterfaceBlock *interfaceBlock = type.getInterfaceBlock();
        declareInterfaceBlock(interfaceBlock);
    }
    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);

        if (!arg->getName().getString().empty())
            out << " " << hashName(arg->getName());
        if (type.isArray())
            out << arrayBrackets(type);

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

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

    if (type.getBasicType() == EbtStruct)
    {
        const TStructure *structure = type.getStruct();
        out << hashName(TName(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 EbtUInt:
                out << pConstUnion->getUConst() << "u";
                break;
              case EbtBool:
                out << pConstUnion->getBConst();
                break;
              default: UNREACHABLE();
            }
            if (i != size - 1)
                out << ", ";
        }
        if (writeType)
            out << ")";
    }
    return pConstUnion;
}

void TOutputGLSLBase::writeConstructorTriplet(Visit visit, const TType &type)
{
    TInfoSinkBase &out = objSink();
    if (visit == PreVisit)
    {
        if (type.isArray())
        {
            out << getTypeName(type);
            out << arrayBrackets(type);
            out << "(";
        }
        else
        {
            out << getTypeName(type) << "(";
        }
    }
    else
    {
        writeTriplet(visit, nullptr, ", ", ")");
    }
}

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

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

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

bool TOutputGLSLBase::visitSwizzle(Visit visit, TIntermSwizzle *node)
{
    TInfoSinkBase &out = objSink();
    if (visit == PostVisit)
    {
        out << ".";
        node->writeOffsetsAsXYZW(&out);
    }
    return true;
}

bool TOutputGLSLBase::visitBinary(Visit visit, TIntermBinary *node)
{
    bool visitChildren = true;
    TInfoSinkBase &out = objSink();
    switch (node->getOp())
    {
        case EOpComma:
            writeTriplet(visit, "(", ", ", ")");
            break;
        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 = static_cast<int>(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(TName(fieldName));

                out << fieldName;
                visitChildren = false;
            }
            break;
        case EOpIndexDirectInterfaceBlock:
            if (visit == InVisit)
            {
                out << ".";
                const TInterfaceBlock *interfaceBlock =
                    node->getLeft()->getType().getInterfaceBlock();
                const TIntermConstantUnion *index = node->getRight()->getAsConstantUnion();
                const TField *field               = interfaceBlock->fields()[index->getIConst(0)];

                TString fieldName = field->name();
                ASSERT(!mSymbolTable.findBuiltIn(interfaceBlock->name(), mShaderVersion));
                fieldName = hashName(TName(fieldName));

                out << fieldName;
                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 EOpTrunc:
        preString = "trunc(";
        break;
      case EOpRound:
        preString = "round(";
        break;
      case EOpRoundEven:
        preString = "roundEven(";
        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::visitTernary(Visit visit, TIntermTernary *node)
{
    TInfoSinkBase &out = objSink();
    // 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->getTrueExpression()->traverse(this);
    out << ") : (";
    node->getFalseExpression()->traverse(this);
    out << "))";
    return false;
}

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

    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 visit, TIntermSwitch *node)
{
    if (node->getStatementList())
    {
        writeTriplet(visit, "switch (", ") ", nullptr);
        // The curly braces get written when visiting the statementList aggregate
    }
    else
    {
        // No statementList, so it won't output curly braces
        writeTriplet(visit, "switch (", ") {", "}\n");
    }
    return true;
}

bool TOutputGLSLBase::visitCase(Visit visit, TIntermCase *node)
{
    if (node->hasCondition())
    {
        writeTriplet(visit, "case (", nullptr, "):\n");
        return true;
    }
    else
    {
        TInfoSinkBase &out = objSink();
        out << "default:\n";
        return false;
    }
}

bool TOutputGLSLBase::visitBlock(Visit visit, TIntermBlock *node)
{
    TInfoSinkBase &out = objSink();
    // Scope the blocks 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 != nullptr);
        curNode->traverse(this);

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

    // Scope the blocks except when at the global scope.
    if (mDepth > 0)
    {
        out << "}\n";
    }
    return false;
}

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

    ASSERT(visit == PreVisit);
    {
        const TType &type = node->getType();
        writeVariableType(type);
        if (type.isArray())
            out << arrayBrackets(type);
    }

    out << " " << hashFunctionNameIfNeeded(node->getFunctionSymbolInfo()->getNameObj());

    incrementDepth(node);

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

    // Traverse function body.
    visitCodeBlock(node->getBody());
    decrementDepth();

    // Fully processed; no need to visit children.
    return false;
}

bool TOutputGLSLBase::visitAggregate(Visit visit, TIntermAggregate *node)
{
    bool visitChildren = true;
    TInfoSinkBase &out = objSink();
    bool useEmulatedFunction = (visit == PreVisit && node->getUseEmulatedFunction());
    switch (node->getOp())
    {
      case EOpPrototype:
        // Function declaration.
        ASSERT(visit == PreVisit);
        {
            const TType &type = node->getType();
            writeVariableType(type);
            if (type.isArray())
                out << arrayBrackets(type);
        }

        out << " " << hashFunctionNameIfNeeded(node->getFunctionSymbolInfo()->getNameObj());

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

        visitChildren = false;
        break;
      case EOpFunctionCall:
        // Function call.
        if (visit == PreVisit)
            out << hashFunctionNameIfNeeded(node->getFunctionSymbolInfo()->getNameObj()) << "(";
        else if (visit == InVisit)
            out << ", ";
        else
            out << ")";
        break;
      case EOpParameters:
        // Function parameters.
        ASSERT(visit == PreVisit);
        out << "(";
        writeFunctionParameters(*(node->getSequence()));
        out << ")";
        visitChildren = 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);
            writeInvariantQualifier(symbol->getType());
            out << hashVariableName(symbol->getName());
        }
        visitChildren = false;
        break;
      case EOpConstructFloat:
      case EOpConstructVec2:
      case EOpConstructVec3:
      case EOpConstructVec4:
      case EOpConstructBool:
      case EOpConstructBVec2:
      case EOpConstructBVec3:
      case EOpConstructBVec4:
      case EOpConstructInt:
      case EOpConstructIVec2:
      case EOpConstructIVec3:
      case EOpConstructIVec4:
      case EOpConstructUInt:
      case EOpConstructUVec2:
      case EOpConstructUVec3:
      case EOpConstructUVec4:
      case EOpConstructMat2:
      case EOpConstructMat2x3:
      case EOpConstructMat2x4:
      case EOpConstructMat3x2:
      case EOpConstructMat3:
      case EOpConstructMat3x4:
      case EOpConstructMat4x2:
      case EOpConstructMat4x3:
      case EOpConstructMat4:
      case EOpConstructStruct:
          writeConstructorTriplet(visit, node->getType());
          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 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::visitDeclaration(Visit visit, TIntermDeclaration *node)
{
    TInfoSinkBase &out = objSink();

    // Variable declaration.
    if (visit == PreVisit)
    {
        const TIntermSequence &sequence = *(node->getSequence());
        const TIntermTyped *variable    = sequence.front()->getAsTyped();
        writeLayoutQualifier(variable->getType());
        writeVariableType(variable->getType());
        out << " ";
        mDeclaringVariables = true;
    }
    else if (visit == InVisit)
    {
        out << ", ";
        mDeclaringVariables = true;
    }
    else
    {
        mDeclaringVariables = false;
    }
    return true;
}

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

    incrementDepth(node);

    TLoopType loopType = node->getType();

    // Only for loops can be unrolled
    ASSERT(!node->getUnrollFlag() || loopType == ELoopFor);

    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";

            visitCodeBlock(node->getBody());
        }
        else
        {
            // Need to put a one-iteration loop here to handle break.
            TIntermSequence *declSeq = node->getInit()->getAsDeclarationNode()->getSequence();
            TIntermSymbol *indexSymbol =
                (*declSeq)[0]->getAsBinaryNode()->getLeft()->getAsSymbolNode();
            TString name = hashVariableName(indexSymbol->getName());
            out << "for (int " << name << " = 0; "
                << name << " < 1; "
                << "++" << name << ")\n";

            out << "{\n";
            mLoopUnrollStack.push(node);
            while (mLoopUnrollStack.satisfiesLoopCondition())
            {
                visitCodeBlock(node->getBody());
                mLoopUnrollStack.step();
            }
            mLoopUnrollStack.pop();
            out << "}\n";
        }
    }
    else if (loopType == ELoopWhile)  // while loop
    {
        out << "while (";
        ASSERT(node->getCondition() != NULL);
        node->getCondition()->traverse(this);
        out << ")\n";

        visitCodeBlock(node->getBody());
    }
    else  // do-while loop
    {
        ASSERT(loopType == ELoopDoWhile);
        out << "do\n";

        visitCodeBlock(node->getBody());

        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(TIntermBlock *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)
{
    if (type.getBasicType() == EbtStruct)
        return hashName(TName(type.getStruct()->name()));
    else
        return type.getBuiltInTypeNameString();
}

TString TOutputGLSLBase::hashName(const TName &name)
{
    if (name.getString().empty())
    {
        ASSERT(!name.isInternal());
        return name.getString();
    }
    if (name.isInternal())
    {
        // TODO(oetuaho): Would be nicer to prefix non-internal names with "_" instead, like is
        // done in the HLSL output, but that requires fairly complex changes elsewhere in the code
        // as well.
        // We need to use a prefix that is reserved in WebGL in order to guarantee that the internal
        // names don't conflict with user-defined names from WebGL.
        return "webgl_angle_" + name.getString();
    }
    if (mHashFunction == nullptr)
    {
        return name.getString();
    }
    NameMap::const_iterator it = mNameMap.find(name.getString().c_str());
    if (it != mNameMap.end())
        return it->second.c_str();
    TString hashedName                 = TIntermTraverser::hash(name.getString(), mHashFunction);
    mNameMap[name.getString().c_str()] = hashedName.c_str();
    return hashedName;
}

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

TString TOutputGLSLBase::hashFunctionNameIfNeeded(const TName &mangledName)
{
    TString mangledStr = mangledName.getString();
    TString name = TFunction::unmangleName(mangledStr);
    if (mSymbolTable.findBuiltIn(mangledStr, mShaderVersion) != nullptr || name == "main")
        return translateTextureFunction(name);
    if (mangledName.isInternal())
    {
        // Internal function names are outputted as-is - they may refer to functions manually added
        // to the output shader source that are not included in the AST at all.
        return name;
    }
    else
    {
        TName nameObj(name);
        return hashName(nameObj);
    }
}

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(TName(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(TName(field->name()));
        if (field->type()->isArray())
            out << arrayBrackets(*field->type());
        out << ";\n";
    }
    out << "}";
}

void TOutputGLSLBase::declareInterfaceBlockLayout(const TInterfaceBlock *interfaceBlock)
{
    TInfoSinkBase &out = objSink();

    out << "layout(";

    switch (interfaceBlock->blockStorage())
    {
        case EbsUnspecified:
        case EbsShared:
            // Default block storage is shared.
            out << "shared";
            break;

        case EbsPacked:
            out << "packed";
            break;

        case EbsStd140:
            out << "std140";
            break;

        default:
            UNREACHABLE();
            break;
    }

    out << ", ";

    switch (interfaceBlock->matrixPacking())
    {
        case EmpUnspecified:
        case EmpColumnMajor:
            // Default matrix packing is column major.
            out << "column_major";
            break;

        case EmpRowMajor:
            out << "row_major";
            break;

        default:
            UNREACHABLE();
            break;
    }

    out << ") ";
}

void TOutputGLSLBase::declareInterfaceBlock(const TInterfaceBlock *interfaceBlock)
{
    TInfoSinkBase &out = objSink();

    out << hashName(TName(interfaceBlock->name())) << "{\n";
    const TFieldList &fields = interfaceBlock->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(TName(field->name()));
        if (field->type()->isArray())
            out << arrayBrackets(*field->type());
        out << ";\n";
    }
    out << "}";
}

}  // namespace sh