Line data    Source code

       1             : /*
       2             :  * Copyright (C) 2012 Apple Inc. All rights reserved.
       3             :  *
       4             :  * Redistribution and use in source and binary forms, with or without
       5             :  * modification, are permitted provided that the following conditions
       6             :  * are met:
       7             :  * 1. Redistributions of source code must retain the above copyright
       8             :  *    notice, this list of conditions and the following disclaimer.
       9             :  * 2. Redistributions in binary form must reproduce the above copyright
      10             :  *    notice, this list of conditions and the following disclaimer in the
      11             :  *    documentation and/or other materials provided with the distribution.
      12             :  *
      13             :  * THIS SOFTWARE IS PROVIDED BY APPLE, INC. ``AS IS'' AND ANY
      14             :  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      15             :  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
      16             :  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE, INC. OR
      17             :  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
      18             :  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
      19             :  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
      20             :  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
      21             :  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      22             :  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      23             :  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      24             :  */
      25             : 
      26             : #include "third_party/compiler/ArrayBoundsClamper.h"
      27             : 
      28             : // The built-in 'clamp' instruction only accepts floats and returns a float.  I
      29             : // iterated a few times with our driver team who examined the output from our
      30             : // compiler - they said the multiple casts generates more code than a single
      31             : // function call.  An inline ternary operator might have been better, but since
      32             : // the index value might be an expression itself, we'd have to make temporary
      33             : // variables to avoid evaluating the expression multiple times.  And making
      34             : // temporary variables was difficult because ANGLE would then need to make more
      35             : // brutal changes to the expression tree.
      36             : 
      37             : const char* kIntClampBegin = "// BEGIN: Generated code for array bounds clamping\n\n";
      38             : const char* kIntClampEnd = "// END: Generated code for array bounds clamping\n\n";
      39             : const char* kIntClampDefinition = "int webgl_int_clamp(int value, int minValue, int maxValue) { return ((value < minValue) ? minValue : ((value > maxValue) ? maxValue : value)); }\n\n";
      40             : 
      41             : namespace sh
      42             : {
      43             : 
      44             : namespace
      45             : {
      46             : 
      47           0 : class ArrayBoundsClamperMarker : public TIntermTraverser {
      48             : public:
      49           0 :     ArrayBoundsClamperMarker()
      50           0 :         : TIntermTraverser(true, false, false),
      51           0 :           mNeedsClamp(false)
      52             :    {
      53           0 :    }
      54             : 
      55           0 :     bool visitBinary(Visit visit, TIntermBinary *node) override
      56             :    {
      57           0 :        if (node->getOp() == EOpIndexIndirect)
      58             :        {
      59           0 :            TIntermTyped* left = node->getLeft();
      60           0 :            if (left->isArray() || left->isVector() || left->isMatrix())
      61             :            {
      62           0 :                node->setAddIndexClamp();
      63           0 :                mNeedsClamp = true;
      64             :            }
      65             :        }
      66           0 :        return true;
      67             :    }
      68             : 
      69           0 :     bool GetNeedsClamp() { return mNeedsClamp; }
      70             : 
      71             : private:
      72             :     bool mNeedsClamp;
      73             : };
      74             : 
      75             : }  // anonymous namespace
      76             : 
      77           0 : ArrayBoundsClamper::ArrayBoundsClamper()
      78             :     : mClampingStrategy(SH_CLAMP_WITH_CLAMP_INTRINSIC)
      79           0 :     , mArrayBoundsClampDefinitionNeeded(false)
      80             : {
      81           0 : }
      82             : 
      83           0 : void ArrayBoundsClamper::SetClampingStrategy(ShArrayIndexClampingStrategy clampingStrategy)
      84             : {
      85           0 :     mClampingStrategy = clampingStrategy;
      86           0 : }
      87             : 
      88           0 : void ArrayBoundsClamper::MarkIndirectArrayBoundsForClamping(TIntermNode* root)
      89             : {
      90           0 :     ASSERT(root);
      91             : 
      92           0 :     ArrayBoundsClamperMarker clamper;
      93           0 :     root->traverse(&clamper);
      94           0 :     if (clamper.GetNeedsClamp())
      95             :     {
      96           0 :         SetArrayBoundsClampDefinitionNeeded();
      97             :     }
      98           0 : }
      99             : 
     100           0 : void ArrayBoundsClamper::OutputClampingFunctionDefinition(TInfoSinkBase& out) const
     101             : {
     102           0 :     if (!mArrayBoundsClampDefinitionNeeded)
     103             :     {
     104           0 :         return;
     105             :     }
     106           0 :     if (mClampingStrategy != SH_CLAMP_WITH_USER_DEFINED_INT_CLAMP_FUNCTION)
     107             :     {
     108           0 :         return;
     109             :     }
     110           0 :     out << kIntClampBegin << kIntClampDefinition << kIntClampEnd;
     111             : }
     112             : 
     113             : }  // namespace sh