ShTransformer.hpp

// Sh: A GPU metaprogramming language.
//
// Copyright 2003-2006 Serious Hack Inc.
// 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
// MA  02110-1301, USA
#ifndef SHTRANSFORMER_HPP
#define SHTRANSFORMER_HPP

#include "ShDllExport.hpp"
#include "ShBackend.hpp"
#include "ShProgram.hpp"
#include "ShCtrlGraph.hpp"
#include "ShInternals.hpp"
#include "ShVariableType.hpp"

namespace SH {

class 
SH_DLLEXPORT ShTransformer {
public:
  ShTransformer(const ShProgramNodePtr& program);
  ~ShTransformer();
  bool changed(); //< returns true iff one of the transformations changed the shader

  typedef std::vector<ShVariableNodePtr> VarNodeVec;
  typedef std::map<ShVariableNodePtr, VarNodeVec> VarSplitMap;
  friend struct VariableSplitter;
  friend struct StatementSplitter;
  void splitTuples(int maxTuple, VarSplitMap &splits);
  
  friend struct InputOutputConvertor;
  void convertInputOutput(ShVarTransformMap *varTransMap = 0);
  
  void convertTextureLookups();

  typedef std::map<ShValueType, ShValueType> ValueTypeMap;  
  void convertToFloat(ValueTypeMap &typeMap);

  //@todo  use dependent uniforms in conversion and spliting functions
  //instead of separate VarSplitMaps and ShVarMaps

  void stripDummyOps();

  void expand_atan2();

  void expand_inverse_hyperbolic();

  void texd_to_texlod();

private:
  ShTransformer(const ShTransformer& other);
  ShTransformer& operator=(const ShTransformer& other);

  ShProgramNodePtr m_program;
  bool m_changed;
};

/* A default transformer.
 * T can overload any of the methods in ShTransformerParent 
 *
 * - void start(const ShProgramNodePtr&)
 *   Does whatever initialization may be necessary.  Initializes changed() to
 *   false.
 *
 * - void handleVarList(ShProgramNode::VarList &varlist, ShBindingType type); 
 *   This is called first and fixes anything that needs to be fixed in the
 *   variable lists. 
 * - handleTexList, handleChannelList, handlePaletteList are similar
 *
 * - bool handleStmt(ShBasicBlock::ShStmtList::iterator &I, const ShCtrlGraphNodePtr& node);
 *   This performs some kind of per-statement transformation during a dfs
 *   through the cfg.  Returns true iff the transformation has already
 *   incremented I (or deleted I and moved I to the next element). 
 *
 * - void finish();
 *   Does any cleanup necessary afterwards, any other transformations to wrap
 *   things up. 
 *
 *   Note - this allows you to split a set of multipass transformations into 
 *   smaller chunks by chaining transformers together.  Have one transformer's
 *   finish call the next transformer's transform()...
 *
 * It must also implement this method:
 * - bool changed()
 *   Returns whether this transformer changed anything
 *
 * @todo range - this sequence of transformations (varlist, statements, finish),
 * might not be the right abstraction...it's just matches most of what we have
 * used so far - first pass identifies something about the variables,
 * second actually fixes the cfg, and final pass does any general stuff
 * that doesn't fit in.
 */ 
template<typename T>
struct ShDefaultTransformer: public T {
  // Applies transformation to the given ctrl graph node. 
  void operator()(const ShCtrlGraphNodePtr& node); 

  // Applies transformation to the given ShProgram 
  bool transform(const ShProgramNodePtr& p); 
};

struct ShTransformerParent {
 ShTransformerParent() : m_changed(false) {}
 void start(const ShProgramNodePtr& program) { m_program = program; }
 void handleVarList(ShProgramNode::VarList &varlist, ShBindingType type) {}
 void handleTexList(ShProgramNode::TexList &texlist) {}
 void handleChannelList(ShProgramNode::ChannelList &chanlist) {}
 void handlePaletteList(ShProgramNode::PaletteList &palettelist) {}

 bool handleStmt(ShBasicBlock::ShStmtList::iterator &I, const ShCtrlGraphNodePtr& node) { return false; }
 void finish() {}
 bool changed() 
 { return m_changed; }

 protected:
   ShProgramNodePtr m_program;
   bool m_changed;
};

}

#include "ShTransformerImpl.hpp"

#endif

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