ShTransformer.hpp

// Sh: A GPU metaprogramming language.
//
// Copyright 2003-2005 Serious Hack Inc.
// 
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// 
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 
// 1. The origin of this software must not be misrepresented; you must
// not claim that you wrote the original software. If you use this
// software in a product, an acknowledgment in the product documentation
// would be appreciated but is not required.
// 
// 2. Altered source versions must be plainly marked as such, and must
// not be misrepresented as being the original software.
// 
// 3. This notice may not be removed or altered from any source
// distribution.
#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::~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();
  
  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();

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(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, 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()(ShCtrlGraphNodePtr node); 

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

struct ShTransformerParent {
 ShTransformerParent() : m_changed(false) {}
 void start(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, 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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