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: Linemap()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 ~Linemap()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 predeclared_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 unknown_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 is_predeclared_location(Location loc)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 is_unknown_location(Location loc)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 location_to_string(Location loc)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 location_to_file(Location loc)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 location_to_line(Location loc)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) 165