1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
//! Used by `rustc` when loading a plugin.
use rustc::middle::cstore::MetadataLoader;
use rustc::session::Session;
use rustc_metadata::locator;
use crate::Registry;
use std::borrow::ToOwned;
use std::env;
use std::mem;
use std::path::PathBuf;
use syntax::ast::{Crate, Ident};
use syntax::struct_span_err;
use syntax::symbol::sym;
use syntax_pos::Span;
use rustc_error_codes::*;
/// Pointer to a registrar function.
type PluginRegistrarFn = fn(&mut Registry<'_>);
fn call_malformed_plugin_attribute(sess: &Session, span: Span) {
struct_span_err!(sess, span, E0498, "malformed `plugin` attribute")
.span_label(span, "malformed attribute")
.emit();
}
/// Read plugin metadata and dynamically load registrar functions.
pub fn load_plugins(sess: &Session,
metadata_loader: &dyn MetadataLoader,
krate: &Crate) -> Vec<PluginRegistrarFn> {
let mut plugins = Vec::new();
for attr in &krate.attrs {
if !attr.check_name(sym::plugin) {
continue;
}
for plugin in attr.meta_item_list().unwrap_or_default() {
match plugin.ident() {
Some(ident) if plugin.is_word() =>
load_plugin(&mut plugins, sess, metadata_loader, ident),
_ => call_malformed_plugin_attribute(sess, plugin.span()),
}
}
}
plugins
}
fn load_plugin(plugins: &mut Vec<PluginRegistrarFn>,
sess: &Session,
metadata_loader: &dyn MetadataLoader,
ident: Ident) {
let registrar = locator::find_plugin_registrar(sess, metadata_loader, ident.span, ident.name);
if let Some((lib, disambiguator)) = registrar {
let symbol = sess.generate_plugin_registrar_symbol(disambiguator);
let fun = dylink_registrar(sess, ident.span, lib, symbol);
plugins.push(fun);
}
}
// Dynamically link a registrar function into the compiler process.
fn dylink_registrar(sess: &Session,
span: Span,
path: PathBuf,
symbol: String) -> PluginRegistrarFn {
use rustc_metadata::dynamic_lib::DynamicLibrary;
// Make sure the path contains a / or the linker will search for it.
let path = env::current_dir().unwrap().join(&path);
let lib = match DynamicLibrary::open(Some(&path)) {
Ok(lib) => lib,
// this is fatal: there are almost certainly macros we need
// inside this crate, so continue would spew "macro undefined"
// errors
Err(err) => {
sess.span_fatal(span, &err)
}
};
unsafe {
let registrar =
match lib.symbol(&symbol) {
Ok(registrar) => {
mem::transmute::<*mut u8, PluginRegistrarFn>(registrar)
}
// again fatal if we can't register macros
Err(err) => {
sess.span_fatal(span, &err)
}
};
// Intentionally leak the dynamic library. We can't ever unload it
// since the library can make things that will live arbitrarily long
// (e.g., an @-box cycle or a thread).
mem::forget(lib);
registrar
}
}
|
