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davidtwcodavidtwco
committedMar 6, 2023
lint/ctypes: check other types for ext. fn-ptr ty
Extend previous checks for external ABI fn-ptrs to use in internal statics, constants, type aliases and algebraic data types. Signed-off-by: David Wood <david.wood@huawei.com>
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4 files changed

+190
-2
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‎compiler/rustc_lint/src/types.rs

+63-1
Original file line numberDiff line numberDiff line change
@@ -1324,7 +1324,11 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
13241324
}
13251325

13261326
let mut visitor = FnPtrFinder { visitor: &*self, spans: Vec::new(), tys: Vec::new() };
1327-
self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty).visit_with(&mut visitor);
1327+
self.cx
1328+
.tcx
1329+
.try_normalize_erasing_regions(self.cx.param_env, ty)
1330+
.unwrap_or(ty)
1331+
.visit_with(&mut visitor);
13281332
hir::intravisit::Visitor::visit_ty(&mut visitor, hir_ty);
13291333

13301334
iter::zip(visitor.tys.drain(..), visitor.spans.drain(..)).collect()
@@ -1348,7 +1352,65 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations {
13481352
}
13491353
}
13501354

1355+
impl ImproperCTypesDefinitions {
1356+
fn check_ty_maybe_containing_foreign_fnptr<'tcx>(
1357+
&mut self,
1358+
cx: &LateContext<'tcx>,
1359+
hir_ty: &'tcx hir::Ty<'_>,
1360+
ty: Ty<'tcx>,
1361+
) {
1362+
let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition };
1363+
for (fn_ptr_ty, span) in vis.find_fn_ptr_ty_with_external_abi(hir_ty, ty) {
1364+
vis.check_type_for_ffi_and_report_errors(span, fn_ptr_ty, true, false);
1365+
}
1366+
}
1367+
}
1368+
1369+
/// `ImproperCTypesDefinitions` checks items outside of foreign items (e.g. stuff that isn't in
1370+
/// `extern "C" { }` blocks):
1371+
///
1372+
/// - `extern "<abi>" fn` definitions are checked in the same way as the
1373+
/// `ImproperCtypesDeclarations` visitor checks functions if `<abi>` is external (e.g. "C").
1374+
/// - All other items which contain types (e.g. other functions, struct definitions, etc) are
1375+
/// checked for extern fn-ptrs with external ABIs.
13511376
impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions {
1377+
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
1378+
match item.kind {
1379+
hir::ItemKind::Static(ty, ..)
1380+
| hir::ItemKind::Const(ty, ..)
1381+
| hir::ItemKind::TyAlias(ty, ..) => {
1382+
self.check_ty_maybe_containing_foreign_fnptr(
1383+
cx,
1384+
ty,
1385+
cx.tcx.type_of(item.owner_id).subst_identity(),
1386+
);
1387+
}
1388+
// See `check_fn`..
1389+
hir::ItemKind::Fn(..) => {}
1390+
// See `check_field_def`..
1391+
hir::ItemKind::Union(..) | hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) => {}
1392+
// Doesn't define something that can contain a external type to be checked.
1393+
hir::ItemKind::Impl(..)
1394+
| hir::ItemKind::TraitAlias(..)
1395+
| hir::ItemKind::Trait(..)
1396+
| hir::ItemKind::OpaqueTy(..)
1397+
| hir::ItemKind::GlobalAsm(..)
1398+
| hir::ItemKind::ForeignMod { .. }
1399+
| hir::ItemKind::Mod(..)
1400+
| hir::ItemKind::Macro(..)
1401+
| hir::ItemKind::Use(..)
1402+
| hir::ItemKind::ExternCrate(..) => {}
1403+
}
1404+
}
1405+
1406+
fn check_field_def(&mut self, cx: &LateContext<'tcx>, field: &'tcx hir::FieldDef<'tcx>) {
1407+
self.check_ty_maybe_containing_foreign_fnptr(
1408+
cx,
1409+
field.ty,
1410+
cx.tcx.type_of(field.def_id).subst_identity(),
1411+
);
1412+
}
1413+
13521414
fn check_fn(
13531415
&mut self,
13541416
cx: &LateContext<'tcx>,

‎tests/ui/hashmap/hashmap-memory.rs

+1
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
// run-pass
22

3+
#![allow(improper_ctypes_definitions)]
34
#![allow(non_camel_case_types)]
45
#![allow(dead_code)]
56
#![allow(unused_mut)]

‎tests/ui/lint/lint-ctypes-94223.rs

+33
Original file line numberDiff line numberDiff line change
@@ -7,3 +7,36 @@ pub fn bad(f: extern "C" fn([u8])) {}
77
pub fn bad_twice(f: Result<extern "C" fn([u8]), extern "C" fn([u8])>) {}
88
//~^ ERROR `extern` fn uses type `[u8]`, which is not FFI-safe
99
//~^^ ERROR `extern` fn uses type `[u8]`, which is not FFI-safe
10+
11+
struct BadStruct(extern "C" fn([u8]));
12+
//~^ ERROR `extern` fn uses type `[u8]`, which is not FFI-safe
13+
14+
enum BadEnum {
15+
A(extern "C" fn([u8])),
16+
//~^ ERROR `extern` fn uses type `[u8]`, which is not FFI-safe
17+
}
18+
19+
enum BadUnion {
20+
A(extern "C" fn([u8])),
21+
//~^ ERROR `extern` fn uses type `[u8]`, which is not FFI-safe
22+
}
23+
24+
type Foo = extern "C" fn([u8]);
25+
//~^ ERROR `extern` fn uses type `[u8]`, which is not FFI-safe
26+
27+
pub struct FfiUnsafe;
28+
29+
#[allow(improper_ctypes_definitions)]
30+
extern "C" fn f(_: FfiUnsafe) {
31+
unimplemented!()
32+
}
33+
34+
pub static BAD: extern "C" fn(FfiUnsafe) = f;
35+
//~^ ERROR `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
36+
37+
pub static BAD_TWICE: Result<extern "C" fn(FfiUnsafe), extern "C" fn(FfiUnsafe)> = Ok(f);
38+
//~^ ERROR `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
39+
//~^^ ERROR `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
40+
41+
pub const BAD_CONST: extern "C" fn(FfiUnsafe) = f;
42+
//~^ ERROR `extern` fn uses type `FfiUnsafe`, which is not FFI-safe

‎tests/ui/lint/lint-ctypes-94223.stderr

+93-1
Original file line numberDiff line numberDiff line change
@@ -30,5 +30,97 @@ LL | pub fn bad_twice(f: Result<extern "C" fn([u8]), extern "C" fn([u8])>) {}
3030
= help: consider using a raw pointer instead
3131
= note: slices have no C equivalent
3232

33-
error: aborting due to 3 previous errors
33+
error: `extern` fn uses type `[u8]`, which is not FFI-safe
34+
--> $DIR/lint-ctypes-94223.rs:11:18
35+
|
36+
LL | struct BadStruct(extern "C" fn([u8]));
37+
| ^^^^^^^^^^^^^^^^^^^ not FFI-safe
38+
|
39+
= help: consider using a raw pointer instead
40+
= note: slices have no C equivalent
41+
42+
error: `extern` fn uses type `[u8]`, which is not FFI-safe
43+
--> $DIR/lint-ctypes-94223.rs:15:7
44+
|
45+
LL | A(extern "C" fn([u8])),
46+
| ^^^^^^^^^^^^^^^^^^^ not FFI-safe
47+
|
48+
= help: consider using a raw pointer instead
49+
= note: slices have no C equivalent
50+
51+
error: `extern` fn uses type `[u8]`, which is not FFI-safe
52+
--> $DIR/lint-ctypes-94223.rs:20:7
53+
|
54+
LL | A(extern "C" fn([u8])),
55+
| ^^^^^^^^^^^^^^^^^^^ not FFI-safe
56+
|
57+
= help: consider using a raw pointer instead
58+
= note: slices have no C equivalent
59+
60+
error: `extern` fn uses type `[u8]`, which is not FFI-safe
61+
--> $DIR/lint-ctypes-94223.rs:24:12
62+
|
63+
LL | type Foo = extern "C" fn([u8]);
64+
| ^^^^^^^^^^^^^^^^^^^ not FFI-safe
65+
|
66+
= help: consider using a raw pointer instead
67+
= note: slices have no C equivalent
68+
69+
error: `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
70+
--> $DIR/lint-ctypes-94223.rs:34:17
71+
|
72+
LL | pub static BAD: extern "C" fn(FfiUnsafe) = f;
73+
| ^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
74+
|
75+
= help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
76+
= note: this struct has unspecified layout
77+
note: the type is defined here
78+
--> $DIR/lint-ctypes-94223.rs:27:1
79+
|
80+
LL | pub struct FfiUnsafe;
81+
| ^^^^^^^^^^^^^^^^^^^^
82+
83+
error: `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
84+
--> $DIR/lint-ctypes-94223.rs:37:30
85+
|
86+
LL | pub static BAD_TWICE: Result<extern "C" fn(FfiUnsafe), extern "C" fn(FfiUnsafe)> = Ok(f);
87+
| ^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
88+
|
89+
= help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
90+
= note: this struct has unspecified layout
91+
note: the type is defined here
92+
--> $DIR/lint-ctypes-94223.rs:27:1
93+
|
94+
LL | pub struct FfiUnsafe;
95+
| ^^^^^^^^^^^^^^^^^^^^
96+
97+
error: `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
98+
--> $DIR/lint-ctypes-94223.rs:37:56
99+
|
100+
LL | pub static BAD_TWICE: Result<extern "C" fn(FfiUnsafe), extern "C" fn(FfiUnsafe)> = Ok(f);
101+
| ^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
102+
|
103+
= help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
104+
= note: this struct has unspecified layout
105+
note: the type is defined here
106+
--> $DIR/lint-ctypes-94223.rs:27:1
107+
|
108+
LL | pub struct FfiUnsafe;
109+
| ^^^^^^^^^^^^^^^^^^^^
110+
111+
error: `extern` fn uses type `FfiUnsafe`, which is not FFI-safe
112+
--> $DIR/lint-ctypes-94223.rs:41:22
113+
|
114+
LL | pub const BAD_CONST: extern "C" fn(FfiUnsafe) = f;
115+
| ^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
116+
|
117+
= help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
118+
= note: this struct has unspecified layout
119+
note: the type is defined here
120+
--> $DIR/lint-ctypes-94223.rs:27:1
121+
|
122+
LL | pub struct FfiUnsafe;
123+
| ^^^^^^^^^^^^^^^^^^^^
124+
125+
error: aborting due to 11 previous errors
34126

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