//
// Create loop nodes.
//
TIntermNode* TIntermediate::addLoop(TIntermNode* body, TIntermTyped* test, TIntermTyped* terminal, bool testFirst, TSourceLoc line)
{
    TIntermNode* node = new TIntermLoop(body, test, terminal, testFirst);
    node->setLine(line);
    
    return node;
}

// 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);
}

//
// Create loop nodes.
//
TIntermNode* TIntermediate::addLoop(TLoopType type, TIntermNode* init, TIntermTyped* cond, TIntermTyped* expr, TIntermNode* body, TSourceLoc line)
{
    TIntermNode* node = new TIntermLoop(type, init, cond, expr, body);
    node->setLine(line);

    return node;
}

bool isChildofMain(TIntermNode *node, TIntermNode *root)
{
    TIntermNode *main = getFunctionBySignature(MAIN_FUNC_SIGNATURE, root);

    if (!main) {
        dbgPrint(DBGLVL_ERROR, "CodeTools - could not find main function\n");
        exit(1);
    }

    TIntermAggregate *aggregate;

    if (!(aggregate = main->getAsAggregate())) {
        dbgPrint(DBGLVL_ERROR, "CodeTools - main is not Aggregate\n");
        exit(1);
    }
    
    TIntermSequence sequence = aggregate->getSequence();
    TIntermSequence::iterator sit;

    for(sit = sequence.begin(); sit != sequence.end(); sit++) {
        if (*sit == node) {
            return true;
        }
    }

    return false;
}

// 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;
}

bool ValidateLimitations::validateForLoopCond(TIntermLoop *node,
                                              int indexSymbolId)
{
    TIntermNode *cond = node->getCondition();
    if (cond == NULL)
    {
        error(node->getLine(), "Missing condition", "for");
        return false;
    }
    //
    // condition has the form:
    //     loop_index relational_operator constant_expression
    //
    TIntermBinary *binOp = cond->getAsBinaryNode();
    if (binOp == NULL)
    {
        error(node->getLine(), "Invalid condition", "for");
        return false;
    }
    // Loop index should be to the left of relational operator.
    TIntermSymbol *symbol = binOp->getLeft()->getAsSymbolNode();
    if (symbol == NULL)
    {
        error(binOp->getLine(), "Invalid condition", "for");
        return false;
    }
    if (symbol->getId() != indexSymbolId)
    {
        error(symbol->getLine(),
              "Expected loop index", symbol->getSymbol().c_str());
        return false;
    }
    // Relational operator is one of: > >= < <= == or !=.
    switch (binOp->getOp())
    {
      case EOpEqual:
      case EOpNotEqual:
      case EOpLessThan:
      case EOpGreaterThan:
      case EOpLessThanEqual:
      case EOpGreaterThanEqual:
        break;
      default:
        error(binOp->getLine(),
              "Invalid relational operator",
              GetOperatorString(binOp->getOp()));
        break;
    }
    // Loop index must be compared with a constant.
    if (!isConstExpr(binOp->getRight()))
    {
        error(binOp->getLine(),
              "Loop index cannot be compared with non-constant expression",
              symbol->getSymbol().c_str());
        return false;
    }

    return true;
}

int ValidateLimitations::validateForLoopInit(TIntermLoop *node)
{
    TIntermNode *init = node->getInit();
    if (init == NULL)
    {
        error(node->getLine(), "Missing init declaration", "for");
        return -1;
    }

    //
    // init-declaration has the form:
    //     type-specifier identifier = constant-expression
    //
    TIntermAggregate *decl = init->getAsAggregate();
    if ((decl == NULL) || (decl->getOp() != EOpDeclaration))
    {
        error(init->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    // To keep things simple do not allow declaration list.
    TIntermSequence &declSeq = decl->getSequence();
    if (declSeq.size() != 1)
    {
        error(decl->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    TIntermBinary *declInit = declSeq[0]->getAsBinaryNode();
    if ((declInit == NULL) || (declInit->getOp() != EOpInitialize))
    {
        error(decl->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    TIntermSymbol *symbol = declInit->getLeft()->getAsSymbolNode();
    if (symbol == NULL)
    {
        error(declInit->getLine(), "Invalid init declaration", "for");
        return -1;
    }
    // The loop index has type int or float.
    TBasicType type = symbol->getBasicType();
    if ((type != EbtInt) && (type != EbtFloat))
    {
        error(symbol->getLine(),
              "Invalid type for loop index", getBasicString(type));
        return -1;
    }
    // The loop index is initialized with constant expression.
    if (!isConstExpr(declInit->getRight()))
    {
        error(declInit->getLine(),
              "Loop index cannot be initialized with non-constant expression",
              symbol->getSymbol().c_str());
        return -1;
    }

    return symbol->getId();
}

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);
    }
}

//
// Create loop nodes.
//
TIntermNode *TIntermediate::addLoop(
    TLoopType type, TIntermNode *init, TIntermTyped *cond, TIntermTyped *expr,
    TIntermNode *body, const TSourceLoc &line)
{
    TIntermNode *node = new TIntermLoop(type, init, cond, expr, ensureSequence(body));
    node->setLine(line);

    return node;
}

int ForLoopUnroll::getLoopIncrement(TIntermLoop* node)
{
    TIntermNode* expr = node->getExpression();
    ASSERT(expr != NULL);
    // for expression has one of the following forms:
    //     loop_index++
    //     loop_index--
    //     loop_index += constant_expression
    //     loop_index -= constant_expression
    //     ++loop_index
    //     --loop_index
    // The last two forms are not specified in the spec, but I am assuming
    // its an oversight.
    TIntermUnary* unOp = expr->getAsUnaryNode();
    TIntermBinary* binOp = unOp ? NULL : expr->getAsBinaryNode();

    TOperator op = EOpNull;
    TIntermConstantUnion* incrementNode = NULL;
    if (unOp != NULL) {
        op = unOp->getOp();
    } else if (binOp != NULL) {
        op = binOp->getOp();
        ASSERT(binOp->getRight() != NULL);
        incrementNode = binOp->getRight()->getAsConstantUnion();
        ASSERT(incrementNode != NULL);
    }

    int increment = 0;
    // The operator is one of: ++ -- += -=.
    switch (op) {
        case EOpPostIncrement:
        case EOpPreIncrement:
            ASSERT((unOp != NULL) && (binOp == NULL));
            increment = 1;
            break;
        case EOpPostDecrement:
        case EOpPreDecrement:
            ASSERT((unOp != NULL) && (binOp == NULL));
            increment = -1;
            break;
        case EOpAddAssign:
            ASSERT((unOp == NULL) && (binOp != NULL));
            increment = evaluateIntConstant(incrementNode);
            break;
        case EOpSubAssign:
            ASSERT((unOp == NULL) && (binOp != NULL));
            increment = - evaluateIntConstant(incrementNode);
            break;
        default:
            ASSERT(false);
    }

    return increment;
}

size_t FindMainIndex(TIntermBlock *root)
{
    const TIntermSequence &sequence = *root->getSequence();
    for (size_t index = 0; index < sequence.size(); ++index)
    {
        TIntermNode *node                       = sequence[index];
        TIntermFunctionDefinition *nodeFunction = node->getAsFunctionDefinition();
        if (nodeFunction != nullptr && nodeFunction->getFunction()->isMain())
        {
            return index;
        }
    }
    return std::numeric_limits<size_t>::max();
}

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;
    }
}

void ForLoopUnroll::FillLoopIndexInfo(TIntermLoop* node, TLoopIndexInfo& info)
{
    ASSERT(node->getType() == ELoopFor);
    ASSERT(node->getUnrollFlag());

    TIntermNode* init = node->getInit();
    ASSERT(init != NULL);
    TIntermAggregate* decl = init->getAsAggregate();
    ASSERT((decl != NULL) && (decl->getOp() == EOpDeclaration));
    TIntermSequence& declSeq = decl->getSequence();
    ASSERT(declSeq.size() == 1);
    TIntermBinary* declInit = declSeq[0]->getAsBinaryNode();
    ASSERT((declInit != NULL) && (declInit->getOp() == EOpInitialize));
    TIntermSymbol* symbol = declInit->getLeft()->getAsSymbolNode();
    ASSERT(symbol != NULL);
    ASSERT(symbol->getBasicType() == EbtInt);

    info.id = symbol->getId();

    ASSERT(declInit->getRight() != NULL);
    TIntermConstantUnion* initNode = declInit->getRight()->getAsConstantUnion();
    ASSERT(initNode != NULL);

    info.initValue = evaluateIntConstant(initNode);
    info.currentValue = info.initValue;

    TIntermNode* cond = node->getCondition();
    ASSERT(cond != NULL);
    TIntermBinary* binOp = cond->getAsBinaryNode();
    ASSERT(binOp != NULL);
    ASSERT(binOp->getRight() != NULL);
    ASSERT(binOp->getRight()->getAsConstantUnion() != NULL);

    info.incrementValue = getLoopIncrement(node);
    info.stopValue = evaluateIntConstant(
        binOp->getRight()->getAsConstantUnion());
    info.op = binOp->getOp();
}

bool ElseBlockRewriter::visitAggregate(Visit visit, TIntermAggregate *node)
{
    switch (node->getOp())
    {
      case EOpSequence:
        {
            for (size_t statementIndex = 0; statementIndex != node->getSequence().size(); statementIndex++)
            {
                TIntermNode *statement = node->getSequence()[statementIndex];
                TIntermSelection *selection = statement->getAsSelectionNode();
                if (selection && selection->getFalseBlock() != NULL)
                {
                    node->getSequence()[statementIndex] = rewriteSelection(selection);
                    delete selection;
                }
            }
        }
        break;

      default: break;
    }

    return true;
}

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

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

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

    // 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;
    }

    TIntermediate intermediate(infoSink);
    TParseContext parseContext(symbolTable, extensionBehavior, intermediate, shaderType, shaderSpec,
                               compileOptions, true, infoSink, getResources());

    parseContext.setFragmentPrecisionHighOnESSL1(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], nullptr, &parseContext) == 0) &&
        (parseContext.getTreeRoot() != nullptr);

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

    TIntermNode *root = nullptr;

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

        root = parseContext.getTreeRoot();
        root = intermediate.postProcess(root);

        // Highp might have been auto-enabled based on shader version
        fragmentPrecisionHigh = parseContext.getFragmentPrecisionHigh();

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

        // Create the function DAG and check there is no recursion
        if (success)
            success = initCallDag(root);

        if (success && (compileOptions & SH_LIMIT_CALL_STACK_DEPTH))
            success = checkCallDepth();

        // 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))
//.........这里部分代码省略.........

// Create loop nodes
TIntermNode* ir_add_loop(TLoopType type, TIntermTyped* cond, TIntermTyped* expr, TIntermNode* body, TSourceLoc line)
{
	TIntermNode* node = new TIntermLoop(type, cond, expr, body);
	node->setLine(line);
	return node;
}