src/compiler/translator/IsASTDepthBelowLimit.cpp

//
// Copyright (c) 2017 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/IsASTDepthBelowLimit.h"

#include "compiler/translator/IntermTraverse.h"

namespace sh
{

namespace
{

// Traverse the tree and compute max depth. Takes a maximum depth limit to prevent stack overflow.
class MaxDepthTraverser : public TIntermTraverser
{
  public:
    MaxDepthTraverser(int depthLimit) : TIntermTraverser(true, true, false), mDepthLimit(depthLimit)
    {
    }

    bool visitBinary(Visit, TIntermBinary *) override { return depthCheck(); }
    bool visitUnary(Visit, TIntermUnary *) override { return depthCheck(); }
    bool visitTernary(Visit, TIntermTernary *) override { return depthCheck(); }
    bool visitSwizzle(Visit, TIntermSwizzle *) override { return depthCheck(); }
    bool visitIfElse(Visit, TIntermIfElse *) override { return depthCheck(); }
    bool visitAggregate(Visit, TIntermAggregate *) override { return depthCheck(); }
    bool visitBlock(Visit, TIntermBlock *) override { return depthCheck(); }
    bool visitLoop(Visit, TIntermLoop *) override { return depthCheck(); }
    bool visitBranch(Visit, TIntermBranch *) override { return depthCheck(); }

  protected:
    bool depthCheck() const { return mMaxDepth < mDepthLimit; }

    int mDepthLimit;
};

}  // anonymous namespace

bool IsASTDepthBelowLimit(TIntermNode *root, int maxDepth)
{
    MaxDepthTraverser traverser(maxDepth + 1);
    root->traverse(&traverser);

    return traverser.getMaxDepth() <= maxDepth;
}

}  // namespace sh