SplitSequenceOperator.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>

src/compiler/translator/tree_ops/SplitSequenceOperator.cpp

//
// Copyright 2016 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.
//
// SplitSequenceOperator is an AST traverser that detects sequence operator expressions that
// go through further AST transformations that generate statements, and splits them so that
// possible side effects of earlier parts of the sequence operator expression are guaranteed to be
// evaluated before the latter parts of the sequence operator expression are evaluated.
//

#include "compiler/translator/tree_ops/SplitSequenceOperator.h"

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

namespace sh
{

namespace
{

class SplitSequenceOperatorTraverser : public TLValueTrackingTraverser
{
  public:
    SplitSequenceOperatorTraverser(unsigned int patternsToSplitMask, TSymbolTable *symbolTable);

    bool visitUnary(Visit visit, TIntermUnary *node) override;
    bool visitBinary(Visit visit, TIntermBinary *node) override;
    bool visitAggregate(Visit visit, TIntermAggregate *node) override;
    bool visitTernary(Visit visit, TIntermTernary *node) override;

    void nextIteration();
    bool foundExpressionToSplit() const { return mFoundExpressionToSplit; }

  protected:
    // Marked to true once an operation that needs to be hoisted out of the expression has been
    // found. After that, no more AST updates are performed on that traversal.
    bool mFoundExpressionToSplit;
    int mInsideSequenceOperator;

    IntermNodePatternMatcher mPatternToSplitMatcher;
};

SplitSequenceOperatorTraverser::SplitSequenceOperatorTraverser(unsigned int patternsToSplitMask,
                                                               TSymbolTable *symbolTable)
    : TLValueTrackingTraverser(true, false, true, symbolTable),
      mFoundExpressionToSplit(false),
      mInsideSequenceOperator(0),
      mPatternToSplitMatcher(patternsToSplitMask)
{}

void SplitSequenceOperatorTraverser::nextIteration()
{
    mFoundExpressionToSplit = false;
    mInsideSequenceOperator = 0;
}

bool SplitSequenceOperatorTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
{
    if (mFoundExpressionToSplit)
        return false;

    if (mInsideSequenceOperator > 0 && visit == PreVisit)
    {
        // Detect expressions that need to be simplified
        mFoundExpressionToSplit = mPatternToSplitMatcher.match(node, getParentNode());
        return !mFoundExpressionToSplit;
    }

    return true;
}

bool SplitSequenceOperatorTraverser::visitUnary(Visit visit, TIntermUnary *node)
{
    if (mFoundExpressionToSplit)
        return false;

    if (mInsideSequenceOperator > 0 && visit == PreVisit)
    {
        // Detect expressions that need to be simplified
        mFoundExpressionToSplit = mPatternToSplitMatcher.match(node);
        return !mFoundExpressionToSplit;
    }

    return true;
}

bool SplitSequenceOperatorTraverser::visitBinary(Visit visit, TIntermBinary *node)
{
    if (node->getOp() == EOpComma)
    {
        if (visit == PreVisit)
        {
            if (mFoundExpressionToSplit)
            {
                return false;
            }
            mInsideSequenceOperator++;
        }
        else if (visit == PostVisit)
        {
            // Split sequence operators starting from the outermost one to preserve correct
            // execution order.
            if (mFoundExpressionToSplit && mInsideSequenceOperator == 1)
            {
                // Move the left side operand into a separate statement in the parent block.
                TIntermSequence insertions;
                insertions.push_back(node->getLeft());
                insertStatementsInParentBlock(insertions);
                // Replace the comma node with its right side operand.
                queueReplacement(node->getRight(), OriginalNode::IS_DROPPED);
            }
            mInsideSequenceOperator--;
        }
        return true;
    }

    if (mFoundExpressionToSplit)
        return false;

    if (mInsideSequenceOperator > 0 && visit == PreVisit)
    {
        // Detect expressions that need to be simplified
        mFoundExpressionToSplit =
            mPatternToSplitMatcher.match(node, getParentNode(), isLValueRequiredHere());
        return !mFoundExpressionToSplit;
    }

    return true;
}

bool SplitSequenceOperatorTraverser::visitTernary(Visit visit, TIntermTernary *node)
{
    if (mFoundExpressionToSplit)
        return false;

    if (mInsideSequenceOperator > 0 && visit == PreVisit)
    {
        // Detect expressions that need to be simplified
        mFoundExpressionToSplit = mPatternToSplitMatcher.match(node);
        return !mFoundExpressionToSplit;
    }

    return true;
}

}  // namespace

void SplitSequenceOperator(TIntermNode *root, int patternsToSplitMask, TSymbolTable *symbolTable)
{
    SplitSequenceOperatorTraverser traverser(patternsToSplitMask, symbolTable);
    // Separate one expression at a time, and reset the traverser between iterations.
    do
    {
        traverser.nextIteration();
        root->traverse(&traverser);
        if (traverser.foundExpressionToSplit())
            traverser.updateTree();
    } while (traverser.foundExpressionToSplit());
}

}  // namespace sh

kc3-lang/angle/src/compiler/translator/tree_ops/SplitSequenceOperator.cpp

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kc3-lang/angle /src/compiler/translator/tree_ops/SplitSequenceOperator.cpp