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// rust-linemap.h -- interface to location tracking -*- C++ -*-
// Copyright 2011 The Go Authors. All rights reserved.
// Copyright (C) 2020-2025 Free Software Foundation, Inc.
// Use of this source code is governed by a BSD-style
// license that can be found in the '../go/gofrontend/LICENSE' file.
#ifndef RUST_LINEMAP_H
#define RUST_LINEMAP_H
#include "rust-system.h"
// The backend must define a type named Location which holds
// information about a location in a source file. The only thing the
// frontend does with instances of Location is pass them back to the
// backend interface. The Location type must be assignable, and it
// must be comparable: i.e., it must support operator= and operator<.
// The type is normally passed by value rather than by reference, and
// it should support that efficiently. The type should be defined in
// "rust-location.h".
#include "rust-location.h"
// The Linemap class is a pure abstract interface, plus some static
// convenience functions. The backend must implement the interface.
/* TODO: probably better to replace linemap implementation as pure abstract
* interface with some sort of compile-time switch (macros or maybe templates if
* doable without too much extra annoyance) as to the definition of the methods
* or whatever. This is to improve performance, as virtual function calls would
* otherwise have to be made in tight loops like in the lexer. */
class Linemap
{
public:
Linemap () : in_file_ (false)
{
// Only one instance of Linemap is allowed to exist.
rust_assert (Linemap::instance_ == NULL);
Linemap::instance_ = this;
}
~Linemap () { Linemap::instance_ = NULL; }
// Subsequent Location values will come from the file named
// FILE_NAME, starting at LINE_BEGIN. Normally LINE_BEGIN will be
// 0, but it will be non-zero if the Rust source has a //line comment.
void start_file (const char *file_name, unsigned int line_begin);
// Stop generating Location values. This will be called after all
// input files have been read, in case any cleanup is required.
void stop ();
protected:
// The single existing instance of Linemap.
static Linemap *instance_;
public:
// Following are convenience static functions, which allow us to
// access some virtual functions without explicitly passing around
// an instance of Linemap.
// Produce a human-readable description of a Location, e.g.
// "foo.rust:10". Returns an empty string for predeclared, builtin or
// unknown locations.
static std::string location_to_string (location_t loc);
private:
// Whether we are currently reading a file.
bool in_file_;
};
#endif // !defined(RUST_LINEMAP_H)
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