gcc/go/gofrontend/go-linemap.h

   1 // go-linemap.h -- interface to location tracking   -*- C++ -*-
   2
   3 // Copyright 2011 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_LINEMAP_H
   8 #define GO_LINEMAP_H
   9
  10 #include "go-system.h"
  11
  12 // The backend must define a type named Location which holds
  13 // information about a location in a source file.  The only thing the
  14 // frontend does with instances of Location is pass them back to the
  15 // backend interface.  The Location type must be assignable, and it
  16 // must be comparable: i.e., it must support operator= and operator<.
  17 // The type is normally passed by value rather than by reference, and
  18 // it should support that efficiently.  The type should be defined in
  19 // "go-location.h".
  20 #include "go-location.h"
  21
  22 // The Linemap class is a pure abstract interface, plus some static
  23 // convenience functions.  The backend must implement the interface.
  24
  25 class Linemap
  26 {
  27  public:
  28   Linemap()
  29   {
  30     // Only one instance of Linemap is allowed to exist.
  31     go_assert(Linemap::instance_ == NULL);
  32     Linemap::instance_ = this;
  33   }
  34
  35   virtual
  36   ~Linemap() { Linemap::instance_ = NULL; }
  37
  38   // Subsequent Location values will come from the file named
  39   // FILE_NAME, starting at LINE_BEGIN.  Normally LINE_BEGIN will be
  40   // 0, but it will be non-zero if the Go source has a //line comment.
  41   virtual void
  42   start_file(const char* file_name, unsigned int line_begin) = 0;
  43
  44   // Subsequent Location values will come from the line LINE_NUMBER,
  45   // in the current file.  LINE_SIZE is the size of the line in bytes.
  46   // This will normally be called for every line in a source file.
  47   virtual void
  48   start_line(unsigned int line_number, unsigned int line_size) = 0;
  49
  50   // Get a Location representing column position COLUMN on the current
  51   // line in the current file.
  52   virtual Location
  53   get_location(unsigned int column) = 0;
  54
  55   // Stop generating Location values.  This will be called after all
  56   // input files have been read, in case any cleanup is required.
  57   virtual void
  58   stop() = 0;
  59
  60   // Produce a human-readable description of a Location, e.g.
  61   // "foo.go:10". Returns an empty string for predeclared, builtin or
  62   // unknown locations.
  63   virtual std::string
  64   to_string(Location) = 0;
  65
  66   // Return the line number for a given location (for debugging dumps)
  67   virtual int
  68   location_line(Location) = 0;
  69
  70  protected:
  71   // Return a special Location used for predeclared identifiers.  This
  72   // Location should be different from that for any actual source
  73   // file.  This location will be used for various different types,
  74   // functions, and objects created by the frontend.
  75   virtual Location
  76   get_predeclared_location() = 0;
  77
  78   // Return a special Location which indicates that no actual location
  79   // is known.  This is used for undefined objects and for errors.
  80   virtual Location
  81   get_unknown_location() = 0;
  82
  83   // Return whether the argument is the Location returned by
  84   // get_predeclared_location.
  85   virtual bool
  86   is_predeclared(Location) = 0;
  87
  88   // Return whether the argument is the Location returned by
  89   // get_unknown_location.
  90   virtual bool
  91   is_unknown(Location) = 0;
  92
  93   // The single existing instance of Linemap.
  94   static Linemap *instance_;
  95
  96  public:
  97   // Following are convenience static functions, which allow us to
  98   // access some virtual functions without explicitly passing around
  99   // an instance of Linemap.
 100
 101   // Return the special Location used for predeclared identifiers.
 102   static Location
 103   predeclared_location()
 104   {
 105     go_assert(Linemap::instance_ != NULL);
 106     return Linemap::instance_->get_predeclared_location();
 107   }
 108
 109   // Return the special Location used when no location is known.
 110   static Location
 111   unknown_location()
 112   {
 113     go_assert(Linemap::instance_ != NULL);
 114     return Linemap::instance_->get_unknown_location();
 115   }
 116
 117   // Return whether the argument is the special location used for
 118   // predeclared identifiers.
 119   static bool
 120   is_predeclared_location(Location loc)
 121   {
 122     go_assert(Linemap::instance_ != NULL);
 123     return Linemap::instance_->is_predeclared(loc);
 124   }
 125
 126   // Return whether the argument is the special location used when no
 127   // location is known.
 128   static bool
 129   is_unknown_location(Location loc)
 130   {
 131     go_assert(Linemap::instance_ != NULL);
 132     return Linemap::instance_->is_unknown(loc);
 133   }
 134
 135   // Produce a human-readable description of a Location.
 136   static std::string
 137   location_to_string(Location loc)
 138   {
 139     go_assert(Linemap::instance_ != NULL);
 140     return Linemap::instance_->to_string(loc);
 141   }
 142
 143   // Return line number for location
 144   static int
 145   location_to_line(Location loc)
 146   {
 147     go_assert(Linemap::instance_ != NULL);
 148     return Linemap::instance_->location_line(loc);
 149   }
 150 };
 151
 152 #endif // !defined(GO_LINEMAP_H)