diff --git a/src/compiler/ValidateLimitations.cpp b/src/compiler/ValidateLimitations.cpp
new file mode 100644
index 0000000..886f693
--- /dev/null
+++ b/src/compiler/ValidateLimitations.cpp
@@ -0,0 +1,468 @@
+//
+// Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+#include "compiler/ValidateLimitations.h"
+#include "compiler/InfoSink.h"
+#include "compiler/ParseHelper.h"
+
+namespace {
+bool IsLoopIndex(const TIntermSymbol* symbol, const TLoopStack& stack) {
+    for (TLoopStack::const_iterator i = stack.begin(); i != stack.end(); ++i) {
+        if (i->index.id == symbol->getId())
+            return true;
+    }
+    return false;
+}
+
+// Traverses a node to check if it represents a constant index expression.
+// Definition:
+// constant-index-expressions are a superset of constant-expressions.
+// Constant-index-expressions can include loop indices as defined in
+// GLSL ES 1.0 spec, Appendix A, section 4.
+// The following are constant-index-expressions:
+// - Constant expressions
+// - Loop indices as defined in section 4
+// - Expressions composed of both of the above
+class ValidateConstIndexExpr : public TIntermTraverser {
+public:
+    ValidateConstIndexExpr(const TLoopStack& stack)
+        : mValid(true), mLoopStack(stack) {}
+
+    // Returns true if the parsed node represents a constant index expression.
+    bool isValid() const { return mValid; }
+
+    virtual void visitSymbol(TIntermSymbol* symbol) {
+        // Only constants and loop indices are allowed in a
+        // constant index expression.
+        if (mValid) {
+            mValid = (symbol->getQualifier() == EvqConst) ||
+                     IsLoopIndex(symbol, mLoopStack);
+        }
+    }
+    virtual void visitConstantUnion(TIntermConstantUnion*) {}
+    virtual bool visitBinary(Visit, TIntermBinary*) { return true; }
+    virtual bool visitUnary(Visit, TIntermUnary*) { return true; }
+    virtual bool visitSelection(Visit, TIntermSelection*) { return true; }
+    virtual bool visitAggregate(Visit, TIntermAggregate*) { return true; }
+    virtual bool visitLoop(Visit, TIntermLoop*) { return true; }
+    virtual bool visitBranch(Visit, TIntermBranch*) { return true; }
+
+private:
+    bool mValid;
+    const TLoopStack& mLoopStack;
+};
+}  // namespace
+
+ValidateLimitations::ValidateLimitations(ShShaderType shaderType,
+                                         TInfoSinkBase& sink)
+    : mShaderType(shaderType),
+      mSink(sink),
+      mNumErrors(0)
+{
+}
+
+void ValidateLimitations::visitSymbol(TIntermSymbol*)
+{
+}
+
+void ValidateLimitations::visitConstantUnion(TIntermConstantUnion*)
+{
+}
+
+bool ValidateLimitations::visitBinary(Visit, TIntermBinary* node)
+{
+    // Check if loop index is modified in the loop body.
+    validateOperation(node, node->getLeft());
+
+    // Check indexing.
+    switch (node->getOp()) {
+      case EOpIndexDirect:
+      case EOpIndexIndirect:
+        validateIndexing(node);
+        break;
+      default: break;
+    }
+    return true;
+}
+
+bool ValidateLimitations::visitUnary(Visit, TIntermUnary* node)
+{
+    // Check if loop index is modified in the loop body.
+    validateOperation(node, node->getOperand());
+
+    return true;
+}
+
+bool ValidateLimitations::visitSelection(Visit, TIntermSelection*)
+{
+    return true;
+}
+
+bool ValidateLimitations::visitAggregate(Visit, TIntermAggregate* node)
+{
+    switch (node->getOp()) {
+      case EOpFunctionCall:
+        validateFunctionCall(node);
+        break;
+      default:
+        break;
+    }
+    return true;
+}
+
+bool ValidateLimitations::visitLoop(Visit, TIntermLoop* node)
+{
+    if (!validateLoopType(node))
+        return false;
+
+    TLoopInfo info;
+    memset(&info, 0, sizeof(TLoopInfo));
+    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 ValidateLimitations::visitBranch(Visit, TIntermBranch*)
+{
+    return true;
+}
+
+void ValidateLimitations::error(TSourceLoc loc,
+                                const char *reason, const char* token)
+{
+    mSink.prefix(EPrefixError);
+    mSink.location(loc);
+    mSink << "'" << token << "' : " << reason << "\n";
+    ++mNumErrors;
+}
+
+bool ValidateLimitations::withinLoopBody() const
+{
+    return !mLoopStack.empty();
+}
+
+bool ValidateLimitations::isLoopIndex(const TIntermSymbol* symbol) const
+{
+    return IsLoopIndex(symbol, mLoopStack);
+}
+
+bool ValidateLimitations::validateLoopType(TIntermLoop* node) {
+    TLoopType type = node->getType();
+    if (type == ELoopFor)
+        return true;
+
+    // Reject while and do-while loops.
+    error(node->getLine(),
+          "This type of loop is not allowed",
+          type == ELoopWhile ? "while" : "do");
+    return false;
+}
+
+bool ValidateLimitations::validateForLoopHeader(TIntermLoop* node,
+                                                TLoopInfo* info)
+{
+    ASSERT(node->getType() == ELoopFor);
+
+    //
+    // The for statement has the form:
+    //    for ( init-declaration ; condition ; expression ) statement
+    //
+    if (!validateForLoopInit(node, info))
+        return false;
+    if (!validateForLoopCond(node, info))
+        return false;
+    if (!validateForLoopExpr(node, info))
+        return false;
+
+    return true;
+}
+
+bool ValidateLimitations::validateForLoopInit(TIntermLoop* node,
+                                              TLoopInfo* info)
+{
+    TIntermNode* init = node->getInit();
+    if (init == NULL) {
+        error(node->getLine(), "Missing init declaration", "for");
+        return false;
+    }
+
+    //
+    // 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 false;
+    }
+    // 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 false;
+    }
+    TIntermBinary* declInit = declSeq[0]->getAsBinaryNode();
+    if ((declInit == NULL) || (declInit->getOp() != EOpInitialize)) {
+        error(decl->getLine(), "Invalid init declaration", "for");
+        return false;
+    }
+    TIntermSymbol* symbol = declInit->getLeft()->getAsSymbolNode();
+    if (symbol == NULL) {
+        error(declInit->getLine(), "Invalid init declaration", "for");
+        return false;
+    }
+    // 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 false;
+    }
+    // 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 false;
+    }
+
+    info->index.id = symbol->getId();
+    return true;
+}
+
+bool ValidateLimitations::validateForLoopCond(TIntermLoop* node,
+                                              TLoopInfo* info)
+{
+    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() != info->index.id) {
+        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;
+}
+
+bool ValidateLimitations::validateForLoopExpr(TIntermLoop* node,
+                                              TLoopInfo* info)
+{
+    TIntermNode* expr = node->getExpression();
+    if (expr == NULL) {
+        error(node->getLine(), "Missing expression", "for");
+        return false;
+    }
+
+    // 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;
+    TIntermSymbol* symbol = NULL;
+    if (unOp != NULL) {
+        op = unOp->getOp();
+        symbol = unOp->getOperand()->getAsSymbolNode();
+    } else if (binOp != NULL) {
+        op = binOp->getOp();
+        symbol = binOp->getLeft()->getAsSymbolNode();
+    }
+
+    // The operand must be loop index.
+    if (symbol == NULL) {
+        error(expr->getLine(), "Invalid expression", "for");
+        return false;
+    }
+    if (symbol->getId() != info->index.id) {
+        error(symbol->getLine(),
+              "Expected loop index", symbol->getSymbol().c_str());
+        return false;
+    }
+
+    // The operator is one of: ++ -- += -=.
+    switch (op) {
+        case EOpPostIncrement:
+        case EOpPostDecrement:
+        case EOpPreIncrement:
+        case EOpPreDecrement:
+            ASSERT((unOp != NULL) && (binOp == NULL));
+            break;
+        case EOpAddAssign:
+        case EOpSubAssign:
+            ASSERT((unOp == NULL) && (binOp != NULL));
+            break;
+        default:
+            error(expr->getLine(), "Invalid operator", getOperatorString(op));
+            return false;
+    }
+
+    // Loop index must be incremented/decremented with a constant.
+    if (binOp != NULL) {
+        if (!isConstExpr(binOp->getRight())) {
+            error(binOp->getLine(),
+                  "Loop index cannot be modified by non-constant expression",
+                  symbol->getSymbol().c_str());
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool ValidateLimitations::validateFunctionCall(TIntermAggregate* node)
+{
+    ASSERT(node->getOp() == EOpFunctionCall);
+
+    // If not within loop body, there is nothing to check.
+    if (!withinLoopBody())
+        return true;
+
+    // List of param indices for which loop indices are used as argument.
+    typedef std::vector<int> ParamIndex;
+    ParamIndex pIndex;
+    TIntermSequence& params = node->getSequence();
+    for (TIntermSequence::size_type i = 0; i < params.size(); ++i) {
+        TIntermSymbol* symbol = params[i]->getAsSymbolNode();
+        if (symbol && isLoopIndex(symbol))
+            pIndex.push_back(i);
+    }
+    // If none of the loop indices are used as arguments,
+    // there is nothing to check.
+    if (pIndex.empty())
+        return true;
+
+    bool valid = true;
+    TSymbolTable& symbolTable = GlobalParseContext->symbolTable;
+    TSymbol* symbol = symbolTable.find(node->getName());
+    ASSERT(symbol && symbol->isFunction());
+    TFunction* function = static_cast<TFunction*>(symbol);
+    for (ParamIndex::const_iterator i = pIndex.begin();
+         i != pIndex.end(); ++i) {
+        const TParameter& param = function->getParam(*i);
+        TQualifier qual = param.type->getQualifier();
+        if ((qual == EvqOut) || (qual == EvqInOut)) {
+            error(params[*i]->getLine(),
+                  "Loop index cannot be used as argument to a function out or inout parameter",
+                  params[*i]->getAsSymbolNode()->getSymbol().c_str());
+            valid = false;
+        }
+    }
+
+    return valid;
+}
+
+bool ValidateLimitations::validateOperation(TIntermOperator* node,
+                                            TIntermNode* operand) {
+    // Check if loop index is modified in the loop body.
+    if (!withinLoopBody() || !node->modifiesState())
+        return true;
+
+    const TIntermSymbol* symbol = operand->getAsSymbolNode();
+    if (symbol && isLoopIndex(symbol)) {
+        error(node->getLine(),
+              "Loop index cannot be statically assigned to within the body of the loop",
+              symbol->getSymbol().c_str());
+    }
+    return true;
+}
+
+bool ValidateLimitations::isConstExpr(TIntermNode* node)
+{
+    ASSERT(node != NULL);
+    return node->getAsConstantUnion() != NULL;
+}
+
+bool ValidateLimitations::isConstIndexExpr(TIntermNode* node)
+{
+    ASSERT(node != NULL);
+
+    ValidateConstIndexExpr validate(mLoopStack);
+    node->traverse(&validate);
+    return validate.isValid();
+}
+
+bool ValidateLimitations::validateIndexing(TIntermBinary* node)
+{
+    ASSERT((node->getOp() == EOpIndexDirect) ||
+           (node->getOp() == EOpIndexIndirect));
+
+    bool valid = true;
+    TIntermTyped* index = node->getRight();
+    // The index expression must have integral type.
+    if (!index->isScalar() || (index->getBasicType() != EbtInt)) {
+        error(index->getLine(),
+              "Index expression must have integral type",
+              index->getCompleteString().c_str());
+        valid = false;
+    }
+    // The index expession must be a constant-index-expression unless
+    // the operand is a uniform in a vertex shader.
+    TIntermTyped* operand = node->getLeft();
+    bool skip = (mShaderType == SH_VERTEX_SHADER) &&
+                (operand->getQualifier() == EvqUniform);
+    if (!skip && !isConstIndexExpr(index)) {
+        error(index->getLine(), "Index expression must be constant", "[]");
+        valid = false;
+    }
+    return valid;
+}
+