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

• Show log

  Commit

• Hash : ea39a223
  Author :
  Date : 2017-07-06T12:47:59
  

  Simplify queueReplacement AST transform helper
  
  queueReplacement is always called to replace the node that's currently
  being visited in the traverser. The currently visited node can be
  fetched automatically from the traversal path so it can be removed
  from parameters of queueReplacement.
  
  BUG=angleproject:2100
  TEST=angle_unittests
  
  Change-Id: I62ab6d1cd9c0d2b4c260af9f7c85bc156fb3f349
  Reviewed-on: https://chromium-review.googlesource.com/562336
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

Download

• 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/IntermTraverse.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(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
  

Download