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
  21 #include "go-location.h"
  22
  23 // The Linemap class is a pure abstract interface, plus some static
  24 // convenience functions.  The backend must implement the interface.
  25
  26 class Linemap
  27 {
  28  public:
  29   Linemap()
  30   {
  31     // Only one instance of Linemap is allowed to exist.
  32     go_assert(Linemap::instance_ == NULL);
  33     Linemap::instance_ = this;
  34   }
  35
  36   virtual
  37   ~Linemap() { Linemap::instance_ = NULL; }
  38
  39   // Subsequent Location values will come from the file named
  40   // FILE_NAME, starting at LINE_BEGIN.  Normally LINE_BEGIN will be
  41   // 0, but it will be non-zero if the Go source has a //line comment.
  42   virtual void
  43   start_file(const char* file_name, unsigned int line_begin) = 0;
  44
  45   // Subsequent Location values will come from the line LINE_NUMBER,
  46   // in the current file.  LINE_SIZE is the size of the line in bytes.
  47   // This will normally be called for every line in a source file.
  48   virtual void
  49   start_line(unsigned int line_number, unsigned int line_size) = 0;
  50
  51   // Get a Location representing column position COLUMN on the current
  52   // line in the current file.
  53   virtual Location
  54   get_location(unsigned int column) = 0;
  55
  56   // Stop generating Location values.  This will be called after all
  57   // input files have been read, in case any cleanup is required.
  58   virtual void
  59   stop() = 0;
  60
  61  protected:
  62   // Return a special Location used for predeclared identifiers.  This
  63   // Location should be different from that for any actual source
  64   // file.  This location will be used for various different types,
  65   // functions, and objects created by the frontend.
  66   virtual Location
  67   get_predeclared_location() = 0;
  68
  69   // Return a special Location which indicates that no actual location
  70   // is known.  This is used for undefined objects and for errors.
  71   virtual Location
  72   get_unknown_location() = 0;
  73
  74   // Return whether the argument is the Location returned by
  75   // get_predeclared_location.
  76   virtual bool
  77   is_predeclared(Location) = 0;
  78
  79   // Return whether the argument is the Location returned by
  80   // get_unknown_location.
  81   virtual bool
  82   is_unknown(Location) = 0;
  83
  84   // The single existing instance of Linemap.
  85   static Linemap *instance_;
  86
  87  public:
  88   // Following are convenience static functions, which allow us to
  89   // access some virtual functions without explicitly passing around
  90   // an instance of Linemap.
  91
  92   // Return the special Location used for predeclared identifiers.
  93   static Location
  94   predeclared_location()
  95   {
  96     go_assert(Linemap::instance_ != NULL);
  97     return Linemap::instance_->get_predeclared_location();
  98   }
  99
 100   // Return the special Location used when no location is known.
 101   static Location
 102   unknown_location()
 103   {
 104     go_assert(Linemap::instance_ != NULL);
 105     return Linemap::instance_->get_unknown_location();
 106   }
 107
 108   // Return whether the argument is the special location used for
 109   // predeclared identifiers.
 110   static bool
 111   is_predeclared_location(Location loc)
 112   {
 113     go_assert(Linemap::instance_ != NULL);
 114     return Linemap::instance_->is_predeclared(loc);
 115   }
 116
 117   // Return whether the argument is the special location used when no
 118   // location is known.
 119   static bool
 120   is_unknown_location(Location loc)
 121   {
 122     go_assert(Linemap::instance_ != NULL);
 123     return Linemap::instance_->is_unknown(loc);
 124   }
 125 };
 126
 127 // The backend interface must define this function.  It should return
 128 // a fully implemented instance of Linemap.
 129 extern Linemap* go_get_linemap();
 130
 131 #endif // !defined(GO_LINEMAP_H)