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

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• Hash : d0bad2c7
  Author :
  Date : 2016-09-09T18:01:16
  

  Split ternary node class from TIntermSelection
  
  Ternary operator nodes are typed parts of expressions, they always
  have two children and the children are also guaranteed to be
  TIntermTyped. "If" selection nodes can't be a part of an expression,
  they can have either one or two children and the children are code
  blocks. Due to all of these differences it makes sense to store these
  using two different AST node classes.
  
  BUG=angleproject:1490
  TEST=angle_unittests
  
  Change-Id: I913ab1d806e3cdb5c21106f078cc9c0b6c72ac54
  Reviewed-on: https://chromium-review.googlesource.com/384512
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  

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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::visitBinary(Visit visit, TIntermBinary *node)
  {
      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::visitAggregate(Visit visit, TIntermAggregate *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 all operands of the sequence operation except the last one into separate
                  // statements in the parent block.
                  TIntermSequence insertions;
                  for (auto *sequenceChild : *node->getSequence())
                  {
                      if (sequenceChild != node->getSequence()->back())
                      {
                          insertions.push_back(sequenceChild);
                      }
                  }
                  insertStatementsInParentBlock(insertions);
                  // Replace the sequence with its last operand
                  queueReplacement(node, node->getSequence()->back(), 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());
          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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