loopvars.h

#ifndef LOOPVARS_H
#define LOOPVARS_H
 
#include <utility>
#include <map>
#include <vector>
#include "ast_visitor.h"
class Symbol;
 
// Produce a ranking of local variables in a function definition by estimating
// how frequently they are used, with the idea that the more deeply nested
// the loop, the more run-time use can be expected.  This visitor should
// be applied to a single function-definition node.
//
// This ranking can be used later to assign callee-saved registers to
// some local variables
class LoopVars : public ASTVisitor {
public:
  typedef std::pair<int, Symbol *> RankedVar;
 
private:
  int m_depth;
  std::map<Symbol *, RankedVar> m_ranked_var_map;
 
public:
  LoopVars();
  virtual ~LoopVars();
 
  std::vector<RankedVar> get_ranked_vars() const;
 
  virtual void visit_while_statement(Node *n);
  virtual void visit_do_while_statement(Node *n);
  virtual void visit_for_statement(Node *n);
  virtual void visit_variable_ref(Node *n);
};
 
#endif // LOOPVARS_H