kc3-lang/angle/src/third_party/compiler/ArrayBoundsClamper.cpp

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• Hash : cccf2b00
  Author :
  Date : 2017-07-05T14:50:54
  

  Reorganize AST traversal utility code
  
  Define TIntermTraverser and TIntermLValueTrackingTraverser in a
  separate header file. hash() function is moved out from
  TIntermTraverser as it is not related to the core functionality
  of traversing and transforming ASTs.
  
  Also reorganize some traversers to follow common conventions:
  
  - Intermediate output is now in OutputTree.h/.cpp
  - Max tree depth check is now in IsASTDepthBelowLimit.h/.cpp
  
  BUG=angleproject:1490
  TEST=angle_unittests
  
  Change-Id: Id4968aa9d4e24d0c5bac90dc147fc9f310de0184
  Reviewed-on: https://chromium-review.googlesource.com/559531
  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/third_party/compiler/ArrayBoundsClamper.cpp

• /*
   * Copyright (C) 2012 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE, INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE, INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "third_party/compiler/ArrayBoundsClamper.h"
  
  #include "compiler/translator/IntermTraverse.h"
  
  // The built-in 'clamp' instruction only accepts floats and returns a float.  I
  // iterated a few times with our driver team who examined the output from our
  // compiler - they said the multiple casts generates more code than a single
  // function call.  An inline ternary operator might have been better, but since
  // the index value might be an expression itself, we'd have to make temporary
  // variables to avoid evaluating the expression multiple times.  And making
  // temporary variables was difficult because ANGLE would then need to make more
  // brutal changes to the expression tree.
  
  const char* kIntClampBegin = "// BEGIN: Generated code for array bounds clamping\n\n";
  const char* kIntClampEnd = "// END: Generated code for array bounds clamping\n\n";
  const char* kIntClampDefinition = "int webgl_int_clamp(int value, int minValue, int maxValue) { return ((value < minValue) ? minValue : ((value > maxValue) ? maxValue : value)); }\n\n";
  
  namespace sh
  {
  
  namespace
  {
  
  class ArrayBoundsClamperMarker : public TIntermTraverser {
  public:
      ArrayBoundsClamperMarker()
          : TIntermTraverser(true, false, false),
            mNeedsClamp(false)
     {
     }
  
      bool visitBinary(Visit visit, TIntermBinary *node) override
     {
         if (node->getOp() == EOpIndexIndirect)
         {
             TIntermTyped* left = node->getLeft();
             if (left->isArray() || left->isVector() || left->isMatrix())
             {
                 node->setAddIndexClamp();
                 mNeedsClamp = true;
             }
         }
         return true;
     }
  
      bool GetNeedsClamp() { return mNeedsClamp; }
  
  private:
      bool mNeedsClamp;
  };
  
  }  // anonymous namespace
  
  ArrayBoundsClamper::ArrayBoundsClamper()
      : mClampingStrategy(SH_CLAMP_WITH_CLAMP_INTRINSIC)
      , mArrayBoundsClampDefinitionNeeded(false)
  {
  }
  
  void ArrayBoundsClamper::SetClampingStrategy(ShArrayIndexClampingStrategy clampingStrategy)
  {
      mClampingStrategy = clampingStrategy;
  }
  
  void ArrayBoundsClamper::MarkIndirectArrayBoundsForClamping(TIntermNode* root)
  {
      ASSERT(root);
  
      ArrayBoundsClamperMarker clamper;
      root->traverse(&clamper);
      if (clamper.GetNeedsClamp())
      {
          SetArrayBoundsClampDefinitionNeeded();
      }
  }
  
  void ArrayBoundsClamper::OutputClampingFunctionDefinition(TInfoSinkBase& out) const
  {
      if (!mArrayBoundsClampDefinitionNeeded)
      {
          return;
      }
      if (mClampingStrategy != SH_CLAMP_WITH_USER_DEFINED_INT_CLAMP_FUNCTION)
      {
          return;
      }
      out << kIntClampBegin << kIntClampDefinition << kIntClampEnd;
  }
  
  }  // namespace sh
  

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