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

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• Hash : d7b1ab58
  Author :
  Date : 2016-12-12T14:42:19
  

  Fix up translator style.
  
  Using git cl format.
  
  BUG=angleproject:650
  
  Change-Id: I7d3f98d2b0dcfb0a8de6c35327db74e55c28d761
  Reviewed-on: https://chromium-review.googlesource.com/419059
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  

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• src/compiler/translator/RemovePow.cpp

• //
  // Copyright (c) 2002-2015 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.
  //
  // RemovePow is an AST traverser to convert pow(x, y) built-in calls where y is a
  // constant to exp2(y * log2(x)). This works around an issue in NVIDIA 311 series
  // OpenGL drivers.
  //
  
  #include "compiler/translator/RemovePow.h"
  
  #include "compiler/translator/InfoSink.h"
  #include "compiler/translator/IntermNode.h"
  
  namespace sh
  {
  
  namespace
  {
  
  bool IsProblematicPow(TIntermTyped *node)
  {
      TIntermAggregate *agg = node->getAsAggregate();
      if (agg != nullptr && agg->getOp() == EOpPow)
      {
          ASSERT(agg->getSequence()->size() == 2);
          return agg->getSequence()->at(1)->getAsConstantUnion() != nullptr;
      }
      return false;
  }
  
  // Traverser that converts all pow operations simultaneously.
  class RemovePowTraverser : public TIntermTraverser
  {
    public:
      RemovePowTraverser();
  
      bool visitAggregate(Visit visit, TIntermAggregate *node) override;
  
      void nextIteration() { mNeedAnotherIteration = false; }
      bool needAnotherIteration() const { return mNeedAnotherIteration; }
  
    protected:
      bool mNeedAnotherIteration;
  };
  
  RemovePowTraverser::RemovePowTraverser()
      : TIntermTraverser(true, false, false), mNeedAnotherIteration(false)
  {
  }
  
  bool RemovePowTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
  {
      if (IsProblematicPow(node))
      {
          TIntermTyped *x = node->getSequence()->at(0)->getAsTyped();
          TIntermTyped *y = node->getSequence()->at(1)->getAsTyped();
  
          TIntermUnary *log = new TIntermUnary(EOpLog2, x);
          log->setLine(node->getLine());
  
          TOperator op       = TIntermBinary::GetMulOpBasedOnOperands(y->getType(), log->getType());
          TIntermBinary *mul = new TIntermBinary(op, y, log);
          mul->setLine(node->getLine());
  
          TIntermUnary *exp = new TIntermUnary(EOpExp2, mul);
          exp->setLine(node->getLine());
  
          queueReplacement(node, exp, OriginalNode::IS_DROPPED);
  
          // If the x parameter also needs to be replaced, we need to do that in another traversal,
          // since it's parent node will change in a way that's not handled correctly by updateTree().
          if (IsProblematicPow(x))
          {
              mNeedAnotherIteration = true;
              return false;
          }
      }
      return true;
  }
  
  }  // namespace
  
  void RemovePow(TIntermNode *root)
  {
      RemovePowTraverser traverser;
      // Iterate as necessary, and reset the traverser between iterations.
      do
      {
          traverser.nextIteration();
          root->traverse(&traverser);
          traverser.updateTree();
      } while (traverser.needAnotherIteration());
  }
  
  }  // namespace sh
  

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