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 file name for a given location.
  67   virtual std::string
  68   location_file(Location) = 0;
  69
  70   // Return the line number for a given location.
  71   virtual int
  72   location_line(Location) = 0;
  73
  74  protected:
  75   // Return a special Location used for predeclared identifiers.  This
  76   // Location should be different from that for any actual source
  77   // file.  This location will be used for various different types,
  78   // functions, and objects created by the frontend.
  79   virtual Location
  80   get_predeclared_location() = 0;
  81
  82   // Return a special Location which indicates that no actual location
  83   // is known.  This is used for undefined objects and for errors.
  84   virtual Location
  85   get_unknown_location() = 0;
  86
  87   // Return whether the argument is the Location returned by
  88   // get_predeclared_location.
  89   virtual bool
  90   is_predeclared(Location) = 0;
  91
  92   // Return whether the argument is the Location returned by
  93   // get_unknown_location.
  94   virtual bool
  95   is_unknown(Location) = 0;
  96
  97   // The single existing instance of Linemap.
  98   static Linemap *instance_;
  99
 100  public:
 101   // Following are convenience static functions, which allow us to
 102   // access some virtual functions without explicitly passing around
 103   // an instance of Linemap.
 104
 105   // Return the special Location used for predeclared identifiers.
 106   static Location
 107   predeclared_location()
 108   {
 109     go_assert(Linemap::instance_ != NULL);
 110     return Linemap::instance_->get_predeclared_location();
 111   }
 112
 113   // Return the special Location used when no location is known.
 114   static Location
 115   unknown_location()
 116   {
 117     go_assert(Linemap::instance_ != NULL);
 118     return Linemap::instance_->get_unknown_location();
 119   }
 120
 121   // Return whether the argument is the special location used for
 122   // predeclared identifiers.
 123   static bool
 124   is_predeclared_location(Location loc)
 125   {
 126     go_assert(Linemap::instance_ != NULL);
 127     return Linemap::instance_->is_predeclared(loc);
 128   }
 129
 130   // Return whether the argument is the special location used when no
 131   // location is known.
 132   static bool
 133   is_unknown_location(Location loc)
 134   {
 135     go_assert(Linemap::instance_ != NULL);
 136     return Linemap::instance_->is_unknown(loc);
 137   }
 138
 139   // Produce a human-readable description of a Location.
 140   static std::string
 141   location_to_string(Location loc)
 142   {
 143     go_assert(Linemap::instance_ != NULL);
 144     return Linemap::instance_->to_string(loc);
 145   }
 146
 147   // Return the file name of a location.
 148   static std::string
 149   location_to_file(Location loc)
 150   {
 151     go_assert(Linemap::instance_ != NULL);
 152     return Linemap::instance_->location_file(loc);
 153   }
 154
 155   // Return line number of a location.
 156   static int
 157   location_to_line(Location loc)
 158   {
 159     go_assert(Linemap::instance_ != NULL);
 160     return Linemap::instance_->location_line(loc);
 161   }
 162 };
 163
 164 #endif // !defined(GO_LINEMAP_H)