rust/src/librustc_plugin/build.rs
2016-06-23 08:07:35 -04:00

64 lines
2.0 KiB
Rust

// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Used by `rustc` when compiling a plugin crate.
use syntax::ast;
use syntax::attr;
use errors;
use syntax_pos::Span;
use rustc::dep_graph::DepNode;
use rustc::hir::map::Map;
use rustc::hir::intravisit::Visitor;
use rustc::hir;
struct RegistrarFinder {
registrars: Vec<(ast::NodeId, Span)> ,
}
impl<'v> Visitor<'v> for RegistrarFinder {
fn visit_item(&mut self, item: &hir::Item) {
if let hir::ItemFn(..) = item.node {
if attr::contains_name(&item.attrs,
"plugin_registrar") {
self.registrars.push((item.id, item.span));
}
}
}
}
/// Find the function marked with `#[plugin_registrar]`, if any.
pub fn find_plugin_registrar(diagnostic: &errors::Handler,
hir_map: &Map)
-> Option<ast::NodeId> {
let _task = hir_map.dep_graph.in_task(DepNode::PluginRegistrar);
let krate = hir_map.krate();
let mut finder = RegistrarFinder { registrars: Vec::new() };
krate.visit_all_items(&mut finder);
match finder.registrars.len() {
0 => None,
1 => {
let (node_id, _) = finder.registrars.pop().unwrap();
Some(node_id)
},
_ => {
let mut e = diagnostic.struct_err("multiple plugin registration functions found");
for &(_, span) in &finder.registrars {
e.span_note(span, "one is here");
}
e.emit();
diagnostic.abort_if_errors();
unreachable!();
}
}
}