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

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• Author : Stuart Morgan
  Date : 2019-08-14 12:25:12
  Hash : 9d737966
  Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>

• src/compiler/translator/tree_ops/RemovePow.cpp

• //
  // Copyright 2002 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/tree_ops/RemovePow.h"
  
  #include "compiler/translator/InfoSink.h"
  #include "compiler/translator/tree_util/IntermNode_util.h"
  #include "compiler/translator/tree_util/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(TSymbolTable *symbolTable);
  
      bool visitAggregate(Visit visit, TIntermAggregate *node) override;
  
      void nextIteration() { mNeedAnotherIteration = false; }
      bool needAnotherIteration() const { return mNeedAnotherIteration; }
  
    protected:
      bool mNeedAnotherIteration;
  };
  
  RemovePowTraverser::RemovePowTraverser(TSymbolTable *symbolTable)
      : TIntermTraverser(true, false, false, symbolTable), 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();
  
          TIntermSequence *logArgs = new TIntermSequence();
          logArgs->push_back(x);
          TIntermTyped *log = CreateBuiltInFunctionCallNode("log2", logArgs, *mSymbolTable, 100);
          log->setLine(node->getLine());
  
          TOperator op       = TIntermBinary::GetMulOpBasedOnOperands(y->getType(), log->getType());
          TIntermBinary *mul = new TIntermBinary(op, y, log);
          mul->setLine(node->getLine());
  
          TIntermSequence *expArgs = new TIntermSequence();
          expArgs->push_back(mul);
          TIntermTyped *exp = CreateBuiltInFunctionCallNode("exp2", expArgs, *mSymbolTable, 100);
          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, TSymbolTable *symbolTable)
  {
      RemovePowTraverser traverser(symbolTable);
      // Iterate as necessary, and reset the traverser between iterations.
      do
      {
          traverser.nextIteration();
          root->traverse(&traverser);
          traverser.updateTree();
      } while (traverser.needAnotherIteration());
  }
  
  }  // namespace sh