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

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• Hash : 4db7ded5
  Author :
  Date : 2016-10-13T12:23:11
  

  Change comma nodes to TIntermBinary
  
  Comma nodes always have just two parameters. If there's an expression
  with several commas in the middle, it's parsed as a tree of comma
  operations. It makes more sense to represent it as a binary node
  rather than an aggregate node.
  
  After this patch, TIntermAggregate is still used for function
  prototypes, function parameter lists, function calls, and variable and
  invariant declarations.
  
  BUG=angleproject:1490
  TEST=angle_unittests, angle_end2end_tests
  
  Change-Id: I66be10624bf27bcf25987b4d93958d4a07600771
  Reviewed-on: https://chromium-review.googlesource.com/397320
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

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• src/compiler/translator/SplitSequenceOperator.cpp

• //
  // Copyright (c) 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/SplitSequenceOperator.h"
  
  #include "compiler/translator/IntermNode.h"
  #include "compiler/translator/IntermNodePatternMatcher.h"
  
  namespace
  {
  
  class SplitSequenceOperatorTraverser : public TLValueTrackingTraverser
  {
    public:
      SplitSequenceOperatorTraverser(unsigned int patternsToSplitMask,
                                     const TSymbolTable &symbolTable,
                                     int shaderVersion);
  
      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,
                                                                 const TSymbolTable &symbolTable,
                                                                 int shaderVersion)
      : TLValueTrackingTraverser(true, false, true, symbolTable, shaderVersion),
        mFoundExpressionToSplit(false),
        mInsideSequenceOperator(0),
        mPatternToSplitMatcher(patternsToSplitMask)
  {
  }
  
  void SplitSequenceOperatorTraverser::nextIteration()
  {
      mFoundExpressionToSplit = false;
      mInsideSequenceOperator = 0;
      nextTemporaryIndex();
  }
  
  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::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, 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,
                             unsigned int *temporaryIndex,
                             const TSymbolTable &symbolTable,
                             int shaderVersion)
  {
      SplitSequenceOperatorTraverser traverser(patternsToSplitMask, symbolTable, shaderVersion);
      ASSERT(temporaryIndex != nullptr);
      traverser.useTemporaryIndex(temporaryIndex);
      // 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());
  }
  

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