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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 : 4642 : Linemap()
29 : 4642 : {
30 : : // Only one instance of Linemap is allowed to exist.
31 : 4642 : go_assert(Linemap::instance_ == NULL);
32 : 4642 : Linemap::instance_ = this;
33 : 4642 : }
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 : 6009214 : predeclared_location()
108 : : {
109 : 6009214 : go_assert(Linemap::instance_ != NULL);
110 : 6009214 : return Linemap::instance_->get_predeclared_location();
111 : : }
112 : :
113 : : // Return the special Location used when no location is known.
114 : : static Location
115 : 11097819 : unknown_location()
116 : : {
117 : 11097819 : go_assert(Linemap::instance_ != NULL);
118 : 11097819 : 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 : 9161797 : is_predeclared_location(Location loc)
125 : : {
126 : 9161797 : go_assert(Linemap::instance_ != NULL);
127 : 9161797 : 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 : 642937 : is_unknown_location(Location loc)
134 : : {
135 : 642937 : go_assert(Linemap::instance_ != NULL);
136 : 642937 : return Linemap::instance_->is_unknown(loc);
137 : : }
138 : :
139 : : // Produce a human-readable description of a Location.
140 : : static std::string
141 : 0 : location_to_string(Location loc)
142 : : {
143 : 0 : go_assert(Linemap::instance_ != NULL);
144 : 0 : return Linemap::instance_->to_string(loc);
145 : : }
146 : :
147 : : // Return the file name of a location.
148 : : static std::string
149 : 16706 : location_to_file(Location loc)
150 : : {
151 : 16706 : go_assert(Linemap::instance_ != NULL);
152 : 16706 : return Linemap::instance_->location_file(loc);
153 : : }
154 : :
155 : : // Return line number of a location.
156 : : static int
157 : 122746 : location_to_line(Location loc)
158 : : {
159 : 122746 : go_assert(Linemap::instance_ != NULL);
160 : 122746 : return Linemap::instance_->location_line(loc);
161 : : }
162 : : };
163 : :
164 : : #endif // !defined(GO_LINEMAP_H)
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