UnfoldShortCircuitAST.cpp

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//

// Copyright 2002 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/tree_ops/apple/UnfoldShortCircuitAST.h"

#include "compiler/translator/IntermNode.h"

#include "compiler/translator/tree_util/IntermNode_util.h"

#include "compiler/translator/tree_util/IntermTraverse.h"

namespace sh

namespace

// "x || y" is equivalent to "x ? true : y".

TIntermTernary *UnfoldOR(TIntermTyped *x, TIntermTyped *y)

    return new TIntermTernary(x, CreateBoolNode(true), y);

// "x && y" is equivalent to "x ? y : false".

TIntermTernary *UnfoldAND(TIntermTyped *x, TIntermTyped *y)

    return new TIntermTernary(x, y, CreateBoolNode(false));

// This traverser identifies all the short circuit binary  nodes that need to

// be replaced, and creates the corresponding replacement nodes. However,

// the actual replacements happen after the traverse through updateTree().

class UnfoldShortCircuitASTTraverser : public TIntermTraverser

  public:

    UnfoldShortCircuitASTTraverser() : TIntermTraverser(true, false, false) {}

    bool visitBinary(Visit visit, TIntermBinary *) override;

};

bool UnfoldShortCircuitASTTraverser::visitBinary(Visit visit, TIntermBinary *node)

    TIntermTernary *replacement = nullptr;

    switch (node->getOp())

        case EOpLogicalOr:

            replacement = UnfoldOR(node->getLeft(), node->getRight());

            break;

        case EOpLogicalAnd:

            replacement = UnfoldAND(node->getLeft(), node->getRight());

            break;

        default:

            break;

    if (replacement)

        queueReplacement(replacement, OriginalNode::IS_DROPPED);

    return true;

}  // anonymous namespace

bool UnfoldShortCircuitAST(TCompiler *compiler, TIntermBlock *root)

    UnfoldShortCircuitASTTraverser traverser;

    root->traverse(&traverser);

    return traverser.updateTree(compiler, root);

}  // namespace sh