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// Copyright 2012 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.
use driver::session;
use driver::session::Session;
use syntax::parse::token::special_idents;
use syntax::ast::{crate, node_id, item, item_fn};
use syntax::codemap::span;
use syntax::visit::{default_visitor, mk_vt, vt, Visitor, visit_crate, visit_item};
use syntax::attr::{attrs_contains_name};
use syntax::ast_map;
use std::util;
struct EntryContext {
session: Session,
ast_map: ast_map::map,
// The top-level function called 'main'
main_fn: Option<(node_id, span)>,
// The function that has attribute named 'main'
attr_main_fn: Option<(node_id, span)>,
// The function that has the attribute 'start' on it
start_fn: Option<(node_id, span)>,
// The functions that one might think are 'main' but aren't, e.g.
// main functions not defined at the top level. For diagnostics.
non_main_fns: ~[(node_id, span)],
}
type EntryVisitor = vt<@mut EntryContext>;
pub fn find_entry_point(session: Session, crate: &crate, ast_map: ast_map::map) {
// FIXME #4404 android JNI hacks
if *session.building_library &&
session.targ_cfg.os != session::os_android {
// No need to find a main function
return;
}
let ctxt = @mut EntryContext {
session: session,
ast_map: ast_map,
main_fn: None,
attr_main_fn: None,
start_fn: None,
non_main_fns: ~[],
};
visit_crate(crate, (ctxt, mk_vt(@Visitor {
visit_item: |item, (ctxt, visitor)| find_item(item, ctxt, visitor),
.. *default_visitor()
})));
configure_main(ctxt);
}
fn find_item(item: @item, ctxt: @mut EntryContext, visitor: EntryVisitor) {
match item.node {
item_fn(*) => {
if item.ident == special_idents::main {
match ctxt.ast_map.find(&item.id) {
Some(&ast_map::node_item(_, path)) => {
if path.len() == 0 {
// This is a top-level function so can be 'main'
if ctxt.main_fn.is_none() {
ctxt.main_fn = Some((item.id, item.span));
} else {
ctxt.session.span_err(
item.span,
"multiple 'main' functions");
}
} else {
// This isn't main
ctxt.non_main_fns.push((item.id, item.span));
}
}
_ => util::unreachable()
}
}
if attrs_contains_name(item.attrs, "main") {
if ctxt.attr_main_fn.is_none() {
ctxt.attr_main_fn = Some((item.id, item.span));
} else {
ctxt.session.span_err(
item.span,
"multiple 'main' functions");
}
}
if attrs_contains_name(item.attrs, "start") {
if ctxt.start_fn.is_none() {
ctxt.start_fn = Some((item.id, item.span));
} else {
ctxt.session.span_err(
item.span,
"multiple 'start' functions");
}
}
}
_ => ()
}
visit_item(item, (ctxt, visitor));
}
fn configure_main(ctxt: @mut EntryContext) {
let this = &mut *ctxt;
if this.start_fn.is_some() {
*this.session.entry_fn = this.start_fn;
*this.session.entry_type = Some(session::EntryStart);
} else if this.attr_main_fn.is_some() {
*this.session.entry_fn = this.attr_main_fn;
*this.session.entry_type = Some(session::EntryMain);
} else if this.main_fn.is_some() {
*this.session.entry_fn = this.main_fn;
*this.session.entry_type = Some(session::EntryMain);
} else {
if !*this.session.building_library {
// No main function
this.session.err("main function not found");
if !this.non_main_fns.is_empty() {
// There were some functions named 'main' though. Try to give the user a hint.
this.session.note("the main function must be defined at the crate level \
but you have one or more functions named 'main' that are not \
defined at the crate level. Either move the definition or \
attach the `#[main]` attribute to override this behavior.");
for this.non_main_fns.iter().advance |&(_, span)| {
this.session.span_note(span, "here is a function named 'main'");
}
}
this.session.abort_if_errors();
} else {
// If we *are* building a library, then we're on android where we still might
// optionally want to translate main $4404
assert_eq!(this.session.targ_cfg.os, session::os_android);
}
}
}
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