gcc/go/gofrontend/dataflow.h

   1 // dataflow.h -- Go frontend dataflow.    -*- C++ -*-
   2
   3 // Copyright 2009 The Go Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style
   5 // license that can be found in the LICENSE file.
   6
   7 #ifndef GO_DATAFLOW_H
   8 #define GO_DATAFLOW_H
   9
  10 class Expression;
  11 class Named_object;
  12 class Statement;
  13
  14 // Dataflow information about the Go program.
  15
  16 class Dataflow
  17 {
  18  public:
  19   // A variable definition.
  20   struct Def
  21   {
  22     // The statement where the variable is defined.
  23     Statement* statement;
  24     // The value to which the variable is set.  This may be NULL.
  25     Expression* val;
  26     // Whether this is an initialization of the variable.
  27     bool is_init;
  28   };
  29
  30   // A variable reference.
  31   struct Ref
  32   {
  33     // The statement where the variable is referenced.
  34     Statement* statement;
  35   };
  36
  37   // A list of defs.
  38   typedef std::vector<Def> Defs;
  39
  40   // A list of refs.
  41   typedef std::vector<Ref> Refs;
  42
  43   Dataflow();
  44
  45   // Initialize the dataflow information.
  46   void
  47   initialize(Gogo*);
  48
  49   // Add a definition of a variable.  STATEMENT assigns a value to
  50   // VAR.  VAL is the value if it is known, NULL otherwise.
  51   void
  52   add_def(Named_object* var, Expression* val, Statement* statement,
  53           bool is_init);
  54
  55   // Add a reference to a variable.  VAR is the variable, and
  56   // STATEMENT is the statement which refers to it.
  57   void
  58   add_ref(Named_object* var, Statement* statement);
  59
  60   // Return the definitions of VAR--the places where it is set.
  61   const Defs*
  62   find_defs(Named_object* var) const;
  63
  64   // Return the references to VAR--the places where it is used.
  65   const Refs*
  66   find_refs(Named_object* var) const;
  67
  68  private:
  69   // Order variables in the map.
  70   struct Compare_vars
  71   {
  72     bool
  73     operator()(const Named_object*, const Named_object*) const;
  74   };
  75
  76   // Map from variables to a list of defs of the variable.  We use a
  77   // map rather than a hash table because the order in which we
  78   // process variables may affect the resulting code.
  79   typedef std::map<Named_object*, Defs*, Compare_vars> Defmap;
  80
  81   // Map from variables to a list of refs to the vairable.
  82   typedef std::map<Named_object*, Refs*, Compare_vars> Refmap;
  83
  84   // Variable defs.
  85   Defmap defs_;
  86   // Variable refs;
  87   Refmap refs_;
  88 };
  89
  90
  91 #endif // !defined(GO_DATAFLOW_H)