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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
// 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.
//! Enforces the Rust effect system. Currently there is just one effect,
/// `unsafe`.
use middle::ty::{ty_bare_fn, ty_closure, ty_ptr};
use middle::ty;
use middle::typeck::method_map;
use util::ppaux;
use syntax::ast::{deref, expr_call, expr_inline_asm, expr_method_call};
use syntax::ast::{expr_unary, node_id, unsafe_blk, unsafe_fn, expr_path};
use syntax::ast;
use syntax::codemap::span;
use syntax::visit::{fk_item_fn, fk_method};
use syntax::visit;
#[deriving(Eq)]
enum UnsafeContext {
SafeContext,
UnsafeFn,
UnsafeBlock(node_id),
}
struct Context {
/// The method map.
method_map: method_map,
/// Whether we're in an unsafe context.
unsafe_context: UnsafeContext,
}
fn type_is_unsafe_function(ty: ty::t) -> bool {
match ty::get(ty).sty {
ty_bare_fn(ref f) => f.purity == unsafe_fn,
ty_closure(ref f) => f.purity == unsafe_fn,
_ => false,
}
}
pub fn check_crate(tcx: ty::ctxt,
method_map: method_map,
crate: &ast::crate) {
let context = @mut Context {
method_map: method_map,
unsafe_context: SafeContext,
};
let require_unsafe: @fn(span: span,
description: &str) = |span, description| {
match context.unsafe_context {
SafeContext => {
// Report an error.
tcx.sess.span_err(span,
fmt!("%s requires unsafe function or block",
description))
}
UnsafeBlock(block_id) => {
// OK, but record this.
debug!("effect: recording unsafe block as used: %?", block_id);
let _ = tcx.used_unsafe.insert(block_id);
}
UnsafeFn => {}
}
};
let visitor = visit::mk_vt(@visit::Visitor {
visit_fn: |fn_kind, fn_decl, block, span, node_id, (_, visitor)| {
let (is_item_fn, is_unsafe_fn) = match *fn_kind {
fk_item_fn(_, _, purity, _) => (true, purity == unsafe_fn),
fk_method(_, _, method) => (true, method.purity == unsafe_fn),
_ => (false, false),
};
let old_unsafe_context = context.unsafe_context;
if is_unsafe_fn {
context.unsafe_context = UnsafeFn
} else if is_item_fn {
context.unsafe_context = SafeContext
}
visit::visit_fn(fn_kind,
fn_decl,
block,
span,
node_id,
((),
visitor));
context.unsafe_context = old_unsafe_context
},
visit_block: |block, (_, visitor)| {
let old_unsafe_context = context.unsafe_context;
if block.node.rules == unsafe_blk &&
context.unsafe_context == SafeContext {
context.unsafe_context = UnsafeBlock(block.node.id)
}
visit::visit_block(block, ((), visitor));
context.unsafe_context = old_unsafe_context
},
visit_expr: |expr, (_, visitor)| {
match expr.node {
expr_method_call(callee_id, _, _, _, _, _) => {
let base_type = ty::node_id_to_type(tcx, callee_id);
debug!("effect: method call case, base type is %s",
ppaux::ty_to_str(tcx, base_type));
if type_is_unsafe_function(base_type) {
require_unsafe(expr.span,
"invocation of unsafe method")
}
}
expr_call(base, _, _) => {
let base_type = ty::node_id_to_type(tcx, base.id);
debug!("effect: call case, base type is %s",
ppaux::ty_to_str(tcx, base_type));
if type_is_unsafe_function(base_type) {
require_unsafe(expr.span, "call to unsafe function")
}
}
expr_unary(_, deref, base) => {
let base_type = ty::node_id_to_type(tcx, base.id);
debug!("effect: unary case, base type is %s",
ppaux::ty_to_str(tcx, base_type));
match ty::get(base_type).sty {
ty_ptr(_) => {
require_unsafe(expr.span,
"dereference of unsafe pointer")
}
_ => {}
}
}
expr_inline_asm(*) => {
require_unsafe(expr.span, "use of inline assembly")
}
expr_path(*) => {
match ty::resolve_expr(tcx, expr) {
ast::def_static(_, true) => {
require_unsafe(expr.span, "use of mutable static")
}
_ => {}
}
}
_ => {}
}
visit::visit_expr(expr, ((), visitor))
},
.. *visit::default_visitor()
});
visit::visit_crate(crate, ((), visitor))
}
|
