kc3-lang/angle/src/compiler/ForLoopUnroll.h

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• Author : zmo@google.com
  Date : 2011-04-04 19:17:11
  Hash : 0b8d4eb2
  Message : Unroll for-loop if sampler array uses loop index as its index. If inside a for-loop, sampler array index is the loop index, Mac cg compiler will crash. This CL unroll the loop in such situation. The behavior is: 1) If the for-loop index is a float, we reject the shader. 2) If it is an integer, we unroll the for-loop. Things that should be done in the future are: 1) Add line number macros. 2) Add a limit to unroll iteration count. anglebug=94 Review URL: http://codereview.appspot.com/4331048 git-svn-id: https://angleproject.googlecode.com/svn/trunk@606 736b8ea6-26fd-11df-bfd4-992fa37f6226

• src/compiler/ForLoopUnroll.h

• //
  // Copyright (c) 2011 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.
  //
  
  #include "compiler/intermediate.h"
  
  struct TLoopIndexInfo {
      int id;
      int initValue;
      int stopValue;
      int incrementValue;
      TOperator op;
      int currentValue;
  };
  
  class ForLoopUnroll {
  public:
      ForLoopUnroll() { }
  
      void FillLoopIndexInfo(TIntermLoop* node, TLoopIndexInfo& info);
  
      // Update the info.currentValue for the next loop iteration.
      void Step();
  
      // Return false if loop condition is no longer satisfied.
      bool SatisfiesLoopCondition();
  
      // Check if the symbol is the index of a loop that's unrolled.
      bool NeedsToReplaceSymbolWithValue(TIntermSymbol* symbol);
  
      // Return the current value of a given loop index symbol.
      int GetLoopIndexValue(TIntermSymbol* symbol);
  
      void Push(TLoopIndexInfo& info);
      void Pop();
  
  private:
      int getLoopIncrement(TIntermLoop* node);
  
      int evaluateIntConstant(TIntermConstantUnion* node);
  
      TVector<TLoopIndexInfo> mLoopIndexStack;
  };