C++ TIntermNode::traverse方法代码示例

// Map I/O variables to provided offsets, and make bindings for
// unbound but live variables.
//
// Returns false if the input is too malformed to do this.
bool TIoMapper::addStage(EShLanguage stage, TIntermediate &intermediate, TInfoSink &infoSink, TIoMapResolver *resolver)
{
    // Trivial return if there is nothing to do.
    if (intermediate.getShiftSamplerBinding() == 0 &&
        intermediate.getShiftTextureBinding() == 0 &&
        intermediate.getShiftImageBinding() == 0 &&
        intermediate.getShiftUboBinding() == 0 &&
        intermediate.getAutoMapBindings() == false &&
        resolver == nullptr)
        return true;

    if (intermediate.getNumEntryPoints() != 1 || intermediate.isRecursive())
        return false;

    TIntermNode* root = intermediate.getTreeRoot();
    if (root == nullptr)
        return false;

    // if no resolver is provided, use the default resolver with the given shifts and auto map settings
    TDefaultIoResolver defaultResolver;
    if (resolver == nullptr) {
        defaultResolver.baseSamplerBinding = intermediate.getShiftSamplerBinding();
        defaultResolver.baseTextureBinding = intermediate.getShiftTextureBinding();
        defaultResolver.baseImageBinding = intermediate.getShiftImageBinding();
        defaultResolver.baseUboBinding = intermediate.getShiftUboBinding();
        defaultResolver.doAutoMapping = intermediate.getAutoMapBindings();

        resolver = &defaultResolver;
    }

    TVarLiveMap varMap;
    TVarGatherTraverser iter_binding_all(intermediate, varMap, true);
    TVarGatherTraverser iter_binding_live(intermediate, varMap, false);

    root->traverse(&iter_binding_all);
    iter_binding_live.pushFunction(intermediate.getEntryPointMangledName().c_str());

    while (!iter_binding_live.functions.empty()) {
        TIntermNode* function = iter_binding_live.functions.back();
        iter_binding_live.functions.pop_back();
        function->traverse(&iter_binding_live);
    }

    // sort entries by priority. see TVarEntryInfo::TOrderByPriority for info.
    std::sort(varMap.begin(), varMap.end(), TVarEntryInfo::TOrderByPriority());

    bool hadError = false;
    TResolverAdaptor doResolve(stage, *resolver, infoSink, hadError);
    std::for_each(varMap.begin(), varMap.end(), doResolve);

    if (!hadError) {
        // sort by id again, so we can use lower bound to find entries
        std::sort(varMap.begin(), varMap.end(), TVarEntryInfo::TOrderById());
        TVarSetTraverser iter_iomap(intermediate, varMap);
        root->traverse(&iter_iomap);
    }

    return !hadError;
}

// Takes an expression like "f(x)" and creates a dependency graph like
// "x -> argument 0 -> function call".
void TDependencyGraphBuilder::visitFunctionCall(TIntermAggregate* intermFunctionCall)
{
    TGraphFunctionCall* functionCall = mGraph->createFunctionCall(intermFunctionCall);

    // Run through the function call arguments.
    int argumentNumber = 0;
    TIntermSequence& intermArguments = intermFunctionCall->getSequence();
    for (TIntermSequence::const_iterator iter = intermArguments.begin();
         iter != intermArguments.end();
         ++iter, ++argumentNumber)
    {
        TNodeSetMaintainer nodeSetMaintainer(this);

        TIntermNode* intermArgument = *iter;
        intermArgument->traverse(this);

        if (TParentNodeSet* argumentNodes = mNodeSets.getTopSet()) {
            TGraphArgument* argument = mGraph->createArgument(intermFunctionCall, argumentNumber);
            connectMultipleNodesToSingleNode(argumentNodes, argument);
            argument->addDependentNode(functionCall);
        }
    }

    // Push the leftmost symbol of this function call into the current set of dependent symbols to
    // represent the result of this function call.
    // Thus, an expression like "y = f(x)" will yield a dependency graph like
    // "x -> argument 0 -> function call -> y".
    // This line essentially passes the function call node back up to an earlier visitAssignment
    // call, which will create the connection "function call -> y".
    mNodeSets.insertIntoTopSet(functionCall);
}

void TDependencyGraphBuilder::visitAggregateChildren(TIntermAggregate* intermAggregate)
{
    TIntermSequence& sequence = intermAggregate->getSequence();
    for(TIntermSequence::const_iterator iter = sequence.begin(); iter != sequence.end(); ++iter)
    {
        TIntermNode* intermChild = *iter;
        intermChild->traverse(this);
    }
}

bool ScalarizeVecAndMatConstructorArgs::visitAggregate(Visit visit, TIntermAggregate *node)
{
    if (visit == PreVisit)
    {
        switch (node->getOp())
        {
          case EOpSequence:
            mSequenceStack.push_back(TIntermSequence());
            {
                for (TIntermSequence::const_iterator iter = node->getSequence()->begin();
                     iter != node->getSequence()->end(); ++iter)
                {
                    TIntermNode *child = *iter;
                    ASSERT(child != NULL);
                    child->traverse(this);
                    mSequenceStack.back().push_back(child);
                }
            }
            if (mSequenceStack.back().size() > node->getSequence()->size())
            {
                node->getSequence()->clear();
                *(node->getSequence()) = mSequenceStack.back();
            }
            mSequenceStack.pop_back();
            return false;
          case EOpConstructVec2:
          case EOpConstructVec3:
          case EOpConstructVec4:
          case EOpConstructBVec2:
          case EOpConstructBVec3:
          case EOpConstructBVec4:
          case EOpConstructIVec2:
          case EOpConstructIVec3:
          case EOpConstructIVec4:
            if (ContainsMatrixNode(*(node->getSequence())))
                scalarizeArgs(node, false, true);
            break;
          case EOpConstructMat2:
          case EOpConstructMat3:
          case EOpConstructMat4:
            if (ContainsVectorNode(*(node->getSequence())))
                scalarizeArgs(node, true, false);
            break;
          default:
            break;
        }
    }
    return true;
}

bool ValidateLimitations::visitLoop(Visit, TIntermLoop *node)
{
    if (!validateLoopType(node))
        return false;

    if (!validateForLoopHeader(node))
        return false;

    TIntermNode *body = node->getBody();
    if (body != NULL)
    {
        mLoopStack.push(node);
        body->traverse(this);
        mLoopStack.pop();
    }

    // The loop is fully processed - no need to visit children.
    return false;
}

// static
bool ValidateLimitations::IsLimitedForLoop(TIntermLoop *loop)
{
    // The shader type doesn't matter in this case.
    ValidateLimitations validate(GL_FRAGMENT_SHADER, nullptr);
    validate.mValidateIndexing   = false;
    validate.mValidateInnerLoops = false;
    if (!validate.validateLoopType(loop))
        return false;
    if (!validate.validateForLoopHeader(loop))
        return false;
    TIntermNode *body = loop->getBody();
    if (body != nullptr)
    {
        validate.mLoopStack.push(loop);
        body->traverse(&validate);
        validate.mLoopStack.pop();
    }
    return (validate.mNumErrors == 0);
}

bool ValidateLimitations::visitLoop(Visit, TIntermLoop* node)
{
    if (!validateLoopType(node))
        return false;

    TLoopInfo info;
    memset(&info, 0, sizeof(TLoopInfo));
    info.loop = node;
    if (!validateForLoopHeader(node, &info))
        return false;

    TIntermNode* body = node->getBody();
    if (body != NULL) {
        mLoopStack.push_back(info);
        body->traverse(this);
        mLoopStack.pop_back();
    }

    // The loop is fully processed - no need to visit children.
    return false;
}

bool RegenerateStructNames::visitAggregate(Visit, TIntermAggregate *aggregate)
{
    ASSERT(aggregate);
    switch (aggregate->getOp())
    {
      case EOpSequence:
        ++mScopeDepth;
        {
            TIntermSequence &sequence = *(aggregate->getSequence());
            for (size_t ii = 0; ii < sequence.size(); ++ii)
            {
                TIntermNode *node = sequence[ii];
                ASSERT(node != NULL);
                node->traverse(this);
            }
        }
        --mScopeDepth;
        return false;
      default:
        return true;
    }
}

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

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

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

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

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

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

            incrementDepth();
            // 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)
            {
                TString functionName = TFunction::unmangleName(node->getName());
                out << functionName << "(";
            }
            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: {
//.........这里部分代码省略.........

//.........这里部分代码省略.........

        // Checks which functions are used and if "main" exists
        if (success)
        {
            functionMetadata.clear();
            functionMetadata.resize(mCallDag.size());
            success = tagUsedFunctions();
        }

        if (success && !(compileOptions & SH_DONT_PRUNE_UNUSED_FUNCTIONS))
            success = pruneUnusedFunctions(root);

        // Prune empty declarations to work around driver bugs and to keep declaration output simple.
        if (success)
            PruneEmptyDeclarations(root);

        if (success && shaderVersion == 300 && shaderType == GL_FRAGMENT_SHADER)
            success = validateOutputs(root);

        if (success && shouldRunLoopAndIndexingValidation(compileOptions))
            success = validateLimitations(root);

        if (success && (compileOptions & SH_TIMING_RESTRICTIONS))
            success = enforceTimingRestrictions(root, (compileOptions & SH_DEPENDENCY_GRAPH) != 0);

        if (success && shaderSpec == SH_CSS_SHADERS_SPEC)
            rewriteCSSShader(root);

        // Unroll for-loop markup needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_INTEGER_INDEX))
        {
            ForLoopUnrollMarker marker(ForLoopUnrollMarker::kIntegerIndex,
                                       shouldRunLoopAndIndexingValidation(compileOptions));
            root->traverse(&marker);
        }
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_SAMPLER_ARRAY_INDEX))
        {
            ForLoopUnrollMarker marker(ForLoopUnrollMarker::kSamplerArrayIndex,
                                       shouldRunLoopAndIndexingValidation(compileOptions));
            root->traverse(&marker);
            if (marker.samplerArrayIndexIsFloatLoopIndex())
            {
                infoSink.info.prefix(EPrefixError);
                infoSink.info << "sampler array index is float loop index";
                success = false;
            }
        }

        // Built-in function emulation needs to happen after validateLimitations pass.
        if (success)
        {
            initBuiltInFunctionEmulator(&builtInFunctionEmulator, compileOptions);
            builtInFunctionEmulator.MarkBuiltInFunctionsForEmulation(root);
        }

        // Clamping uniform array bounds needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_CLAMP_INDIRECT_ARRAY_BOUNDS))
            arrayBoundsClamper.MarkIndirectArrayBoundsForClamping(root);

        // gl_Position is always written in compatibility output mode
        if (success && shaderType == GL_VERTEX_SHADER &&
            ((compileOptions & SH_INIT_GL_POSITION) ||
             (outputType == SH_GLSL_COMPATIBILITY_OUTPUT)))
            initializeGLPosition(root);

        // This pass might emit short circuits so keep it before the short circuit unfolding

bool TOutputGLSLBase::visitAggregate(Visit visit, TIntermAggregate *node)
{
    bool visitChildren = true;
    TInfoSinkBase &out = objSink();
    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);
        {
            const TType &type = node->getType();
            writeVariableType(type);
            if (type.isArray())
                out << arrayBrackets(type);
        }

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

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

        visitChildren = false;
        break;
      case EOpFunction: {
        // Function definition.
        ASSERT(visit == PreVisit);
        {
            const TType &type = node->getType();
            writeVariableType(type);
            if (type.isArray())
                out << arrayBrackets(type);
        }

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

        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 << hashFunctionNameIfNeeded(node->getNameObj()) << "(";
        else if (visit == InVisit)
            out << ", ";
        else
            out << ")";
        break;
      case EOpParameters:
        // Function parameters.
        ASSERT(visit == PreVisit);
//.........这里部分代码省略.........

TIntermNode *TCompiler::compileTreeImpl(const char* const shaderStrings[],
    size_t numStrings, int compileOptions)
{
    clearResults();

    ASSERT(numStrings > 0);
    ASSERT(GetGlobalPoolAllocator());

    // Reset the extension behavior for each compilation unit.
    ResetExtensionBehavior(extensionBehavior);

    // If compiling for WebGL, validate loop and indexing as well.
    if (IsWebGLBasedSpec(shaderSpec))
        compileOptions |= SH_VALIDATE_LOOP_INDEXING;

    // First string is path of source file if flag is set. The actual source follows.
    size_t firstSource = 0;
    if (compileOptions & SH_SOURCE_PATH)
    {
        mSourcePath = shaderStrings[0];
        ++firstSource;
    }

    bool debugShaderPrecision = getResources().WEBGL_debug_shader_precision == 1;
    TIntermediate intermediate(infoSink);
    TParseContext parseContext(symbolTable, extensionBehavior, intermediate,
                               shaderType, shaderSpec, compileOptions, true,
                               infoSink, debugShaderPrecision);

    parseContext.fragmentPrecisionHigh = fragmentPrecisionHigh;
    SetGlobalParseContext(&parseContext);

    // We preserve symbols at the built-in level from compile-to-compile.
    // Start pushing the user-defined symbols at global level.
    TScopedSymbolTableLevel scopedSymbolLevel(&symbolTable);

    // Parse shader.
    bool success =
        (PaParseStrings(numStrings - firstSource, &shaderStrings[firstSource], NULL, &parseContext) == 0) &&
        (parseContext.treeRoot != NULL);

    shaderVersion = parseContext.getShaderVersion();
    if (success && MapSpecToShaderVersion(shaderSpec) < shaderVersion)
    {
        infoSink.info.prefix(EPrefixError);
        infoSink.info << "unsupported shader version";
        success = false;
    }

    TIntermNode *root = NULL;

    if (success)
    {
        mPragma = parseContext.pragma();
        if (mPragma.stdgl.invariantAll)
        {
            symbolTable.setGlobalInvariant();
        }

        root = parseContext.treeRoot;
        success = intermediate.postProcess(root);

        // Disallow expressions deemed too complex.
        if (success && (compileOptions & SH_LIMIT_EXPRESSION_COMPLEXITY))
            success = limitExpressionComplexity(root);

        if (success)
            success = detectCallDepth(root, infoSink, (compileOptions & SH_LIMIT_CALL_STACK_DEPTH) != 0);

        if (success && shaderVersion == 300 && shaderType == GL_FRAGMENT_SHADER)
            success = validateOutputs(root);

        if (success && (compileOptions & SH_VALIDATE_LOOP_INDEXING))
            success = validateLimitations(root);

        if (success && (compileOptions & SH_TIMING_RESTRICTIONS))
            success = enforceTimingRestrictions(root, (compileOptions & SH_DEPENDENCY_GRAPH) != 0);

        if (success && shaderSpec == SH_CSS_SHADERS_SPEC)
            rewriteCSSShader(root);

        // Unroll for-loop markup needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_INTEGER_INDEX))
        {
            ForLoopUnrollMarker marker(ForLoopUnrollMarker::kIntegerIndex);
            root->traverse(&marker);
        }
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_SAMPLER_ARRAY_INDEX))
        {
            ForLoopUnrollMarker marker(ForLoopUnrollMarker::kSamplerArrayIndex);
            root->traverse(&marker);
            if (marker.samplerArrayIndexIsFloatLoopIndex())
            {
                infoSink.info.prefix(EPrefixError);
                infoSink.info << "sampler array index is float loop index";
                success = false;
            }
        }

        // Built-in function emulation needs to happen after validateLimitations pass.
//.........这里部分代码省略.........

bool TCompiler::compile(const char* const shaderStrings[],
                        size_t numStrings,
                        int compileOptions)
{
    TScopedPoolAllocator scopedAlloc(&allocator);
    clearResults();

    if (numStrings == 0)
        return true;

    // If compiling for WebGL, validate loop and indexing as well.
    if (IsWebGLBasedSpec(shaderSpec))
        compileOptions |= SH_VALIDATE_LOOP_INDEXING;

    // First string is path of source file if flag is set. The actual source follows.
    const char* sourcePath = NULL;
    size_t firstSource = 0;
    if (compileOptions & SH_SOURCE_PATH)
    {
        sourcePath = shaderStrings[0];
        ++firstSource;
    }

    TIntermediate intermediate(infoSink);
    TParseContext parseContext(symbolTable, extensionBehavior, intermediate,
                               shaderType, shaderSpec, compileOptions, true,
                               sourcePath, infoSink);
    parseContext.fragmentPrecisionHigh = fragmentPrecisionHigh;
    SetGlobalParseContext(&parseContext);

    // We preserve symbols at the built-in level from compile-to-compile.
    // Start pushing the user-defined symbols at global level.
    TScopedSymbolTableLevel scopedSymbolLevel(&symbolTable);

    // Parse shader.
    bool success =
        (PaParseStrings(numStrings - firstSource, &shaderStrings[firstSource], NULL, &parseContext) == 0) &&
        (parseContext.treeRoot != NULL);

    shaderVersion = parseContext.getShaderVersion();

    if (success)
    {
        TIntermNode* root = parseContext.treeRoot;
        success = intermediate.postProcess(root);

        // Disallow expressions deemed too complex.
        if (success && (compileOptions & SH_LIMIT_EXPRESSION_COMPLEXITY))
            success = limitExpressionComplexity(root);

        if (success)
            success = detectCallDepth(root, infoSink, (compileOptions & SH_LIMIT_CALL_STACK_DEPTH) != 0);

        if (success && shaderVersion == 300 && shaderType == GL_FRAGMENT_SHADER)
            success = validateOutputs(root);

        if (success && (compileOptions & SH_VALIDATE_LOOP_INDEXING))
            success = validateLimitations(root);

        if (success && (compileOptions & SH_TIMING_RESTRICTIONS))
            success = enforceTimingRestrictions(root, (compileOptions & SH_DEPENDENCY_GRAPH) != 0);

        if (success && shaderSpec == SH_CSS_SHADERS_SPEC)
            rewriteCSSShader(root);

        // Unroll for-loop markup needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_INTEGER_INDEX))
        {
            ForLoopUnrollMarker marker(ForLoopUnrollMarker::kIntegerIndex);
            root->traverse(&marker);
        }
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_SAMPLER_ARRAY_INDEX))
        {
            ForLoopUnrollMarker marker(ForLoopUnrollMarker::kSamplerArrayIndex);
            root->traverse(&marker);
            if (marker.samplerArrayIndexIsFloatLoopIndex())
            {
                infoSink.info.prefix(EPrefixError);
                infoSink.info << "sampler array index is float loop index";
                success = false;
            }
        }

        // Built-in function emulation needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_EMULATE_BUILT_IN_FUNCTIONS))
            builtInFunctionEmulator.MarkBuiltInFunctionsForEmulation(root);

        // Clamping uniform array bounds needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_CLAMP_INDIRECT_ARRAY_BOUNDS))
            arrayBoundsClamper.MarkIndirectArrayBoundsForClamping(root);

        if (success && shaderType == GL_VERTEX_SHADER && (compileOptions & SH_INIT_GL_POSITION))
            initializeGLPosition(root);

        if (success && (compileOptions & SH_UNFOLD_SHORT_CIRCUIT))
        {
            UnfoldShortCircuitAST unfoldShortCircuit;
            root->traverse(&unfoldShortCircuit);
            unfoldShortCircuit.updateTree();
        }
//.........这里部分代码省略.........