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

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• Hash : a07b4213
  Author :
  Date : 2018-03-22T16:13:13
  

  Move AST transformations to a subdirectory
  
  Move AST transformations to compiler/translator/tree_ops.
  
  BUG=angleproject:2409
  TEST=angle_unittests
  
  Change-Id: I9c620e98707d22d005da6192fe7d1b4e8030aadd
  Reviewed-on: https://chromium-review.googlesource.com/975550
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

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• src/compiler/translator/tree_ops/RemoveArrayLengthMethod.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.
  //
  // RemoveArrayLengthMethod.cpp:
  //   Fold array length expressions, including cases where the "this" node has side effects.
  //   Example:
  //     int i = (a = b).length();
  //     int j = (func()).length();
  //   becomes:
  //     (a = b);
  //     int i = <constant array length>;
  //     func();
  //     int j = <constant array length>;
  //
  //   Must be run after SplitSequenceOperator, SimplifyLoopConditions and SeparateDeclarations steps
  //   have been done to expressions containing calls of the array length method.
  //
  //   Does nothing to length method calls done on runtime-sized arrays.
  
  #include "compiler/translator/tree_ops/RemoveArrayLengthMethod.h"
  
  #include "compiler/translator/IntermNode.h"
  #include "compiler/translator/tree_util/IntermTraverse.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class RemoveArrayLengthTraverser : public TIntermTraverser
  {
    public:
      RemoveArrayLengthTraverser() : TIntermTraverser(true, false, false), mFoundArrayLength(false) {}
  
      bool visitUnary(Visit visit, TIntermUnary *node) override;
  
      void nextIteration() { mFoundArrayLength = false; }
  
      bool foundArrayLength() const { return mFoundArrayLength; }
  
    private:
      bool mFoundArrayLength;
  };
  
  bool RemoveArrayLengthTraverser::visitUnary(Visit visit, TIntermUnary *node)
  {
      // The only case where we leave array length() in place is for runtime-sized arrays.
      if (node->getOp() == EOpArrayLength && !node->getOperand()->getType().isUnsizedArray())
      {
          mFoundArrayLength = true;
          if (!node->getOperand()->hasSideEffects())
          {
              queueReplacement(node->fold(nullptr), OriginalNode::IS_DROPPED);
              return false;
          }
          insertStatementInParentBlock(node->getOperand()->deepCopy());
          TConstantUnion *constArray = new TConstantUnion[1];
          constArray->setIConst(node->getOperand()->getOutermostArraySize());
          queueReplacement(new TIntermConstantUnion(constArray, node->getType()),
                           OriginalNode::IS_DROPPED);
          return false;
      }
      return true;
  }
  
  }  // anonymous namespace
  
  void RemoveArrayLengthMethod(TIntermBlock *root)
  {
      RemoveArrayLengthTraverser traverser;
      do
      {
          traverser.nextIteration();
          root->traverse(&traverser);
          if (traverser.foundArrayLength())
              traverser.updateTree();
      } while (traverser.foundArrayLength());
  }
  
  }  // namespace sh
  

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