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improper_ctypes lint: allow 128 bit integers for the sysv64 ABI #78481

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improper_ctypes lint: allow 128 bit integers for the sysv64 ABI #78481

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67 changes: 42 additions & 25 deletions compiler/rustc_lint/src/types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -808,22 +808,24 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
fn check_field_type_for_ffi(
&self,
cache: &mut FxHashSet<Ty<'tcx>>,
abi: SpecAbi,
field: &ty::FieldDef,
substs: SubstsRef<'tcx>,
) -> FfiResult<'tcx> {
let field_ty = field.ty(self.cx.tcx, substs);
if field_ty.has_opaque_types() {
self.check_type_for_ffi(cache, field_ty)
self.check_type_for_ffi(cache, abi, field_ty)
} else {
let field_ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, field_ty);
self.check_type_for_ffi(cache, field_ty)
self.check_type_for_ffi(cache, abi, field_ty)
}
}

/// Checks if the given `VariantDef`'s field types are "ffi-safe".
fn check_variant_for_ffi(
&self,
cache: &mut FxHashSet<Ty<'tcx>>,
abi: SpecAbi,
ty: Ty<'tcx>,
def: &ty::AdtDef,
variant: &ty::VariantDef,
Expand All @@ -835,7 +837,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
// Can assume that only one field is not a ZST, so only check
// that field's type for FFI-safety.
if let Some(field) = transparent_newtype_field(self.cx.tcx, variant) {
self.check_field_type_for_ffi(cache, field, substs)
self.check_field_type_for_ffi(cache, abi, field, substs)
} else {
bug!("malformed transparent type");
}
Expand All @@ -844,7 +846,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
// actually safe.
let mut all_phantom = !variant.fields.is_empty();
for field in &variant.fields {
match self.check_field_type_for_ffi(cache, &field, substs) {
match self.check_field_type_for_ffi(cache, abi, &field, substs) {
FfiSafe => {
all_phantom = false;
}
Expand All @@ -866,7 +868,12 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {

/// Checks if the given type is "ffi-safe" (has a stable, well-defined
/// representation which can be exported to C code).
fn check_type_for_ffi(&self, cache: &mut FxHashSet<Ty<'tcx>>, ty: Ty<'tcx>) -> FfiResult<'tcx> {
fn check_type_for_ffi(
&self,
cache: &mut FxHashSet<Ty<'tcx>>,
abi: SpecAbi,
ty: Ty<'tcx>,
) -> FfiResult<'tcx> {
use FfiResult::*;

let tcx = self.cx.tcx;
Expand Down Expand Up @@ -922,7 +929,14 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
};
}

self.check_variant_for_ffi(cache, ty, def, def.non_enum_variant(), substs)
self.check_variant_for_ffi(
cache,
abi,
ty,
def,
def.non_enum_variant(),
substs,
)
}
AdtKind::Enum => {
if def.variants.is_empty() {
Expand Down Expand Up @@ -967,7 +981,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
};
}

match self.check_variant_for_ffi(cache, ty, def, variant, substs) {
match self.check_variant_for_ffi(cache, abi, ty, def, variant, substs) {
FfiSafe => (),
r => return r,
}
Expand All @@ -984,11 +998,13 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
help: Some("consider using `u32` or `libc::wchar_t` instead".into()),
},

ty::Int(ast::IntTy::I128) | ty::Uint(ast::UintTy::U128) => FfiUnsafe {
ty,
reason: "128-bit integers don't currently have a known stable ABI".into(),
help: None,
},
ty::Int(ast::IntTy::I128) | ty::Uint(ast::UintTy::U128) if abi != SpecAbi::SysV64 => {
FfiUnsafe {
ty,
reason: "128-bit integers don't currently have a known stable ABI".into(),
help: None,
}
}

// Primitive types with a stable representation.
ty::Bool | ty::Int(..) | ty::Uint(..) | ty::Float(..) | ty::Never => FfiSafe,
Expand Down Expand Up @@ -1025,10 +1041,10 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
}

ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) => {
self.check_type_for_ffi(cache, ty)
self.check_type_for_ffi(cache, abi, ty)
}

ty::Array(inner_ty, _) => self.check_type_for_ffi(cache, inner_ty),
ty::Array(inner_ty, _) => self.check_type_for_ffi(cache, abi, inner_ty),

ty::FnPtr(sig) => {
if self.is_internal_abi(sig.abi()) {
Expand All @@ -1045,7 +1061,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {

let sig = tcx.erase_late_bound_regions(&sig);
if !sig.output().is_unit() {
let r = self.check_type_for_ffi(cache, sig.output());
let r = self.check_type_for_ffi(cache, abi, sig.output());
match r {
FfiSafe => {}
_ => {
Expand All @@ -1054,7 +1070,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
}
}
for arg in sig.inputs() {
let r = self.check_type_for_ffi(cache, arg);
let r = self.check_type_for_ffi(cache, abi, arg);
match r {
FfiSafe => {}
_ => {
Expand Down Expand Up @@ -1166,6 +1182,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {

fn check_type_for_ffi_and_report_errors(
&mut self,
abi: SpecAbi,
sp: Span,
ty: Ty<'tcx>,
is_static: bool,
Expand Down Expand Up @@ -1196,7 +1213,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
return;
}

match self.check_type_for_ffi(&mut FxHashSet::default(), ty) {
match self.check_type_for_ffi(&mut FxHashSet::default(), abi, ty) {
FfiResult::FfiSafe => {}
FfiResult::FfiPhantom(ty) => {
self.emit_ffi_unsafe_type_lint(ty, sp, "composed only of `PhantomData`", None);
Expand All @@ -1210,25 +1227,25 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
}
}

fn check_foreign_fn(&mut self, id: hir::HirId, decl: &hir::FnDecl<'_>) {
fn check_foreign_fn(&mut self, abi: SpecAbi, id: hir::HirId, decl: &hir::FnDecl<'_>) {
let def_id = self.cx.tcx.hir().local_def_id(id);
let sig = self.cx.tcx.fn_sig(def_id);
let sig = self.cx.tcx.erase_late_bound_regions(&sig);

for (input_ty, input_hir) in sig.inputs().iter().zip(decl.inputs) {
self.check_type_for_ffi_and_report_errors(input_hir.span, input_ty, false, false);
self.check_type_for_ffi_and_report_errors(abi, input_hir.span, input_ty, false, false);
}

if let hir::FnRetTy::Return(ref ret_hir) = decl.output {
let ret_ty = sig.output();
self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty, false, true);
self.check_type_for_ffi_and_report_errors(abi, ret_hir.span, ret_ty, false, true);
}
}

fn check_foreign_static(&mut self, id: hir::HirId, span: Span) {
fn check_foreign_static(&mut self, abi: SpecAbi, id: hir::HirId, span: Span) {
let def_id = self.cx.tcx.hir().local_def_id(id);
let ty = self.cx.tcx.type_of(def_id);
self.check_type_for_ffi_and_report_errors(span, ty, true, false);
self.check_type_for_ffi_and_report_errors(abi, span, ty, true, false);
}

fn is_internal_abi(&self, abi: SpecAbi) -> bool {
Expand All @@ -1252,10 +1269,10 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations {
if !vis.is_internal_abi(abi) {
match it.kind {
hir::ForeignItemKind::Fn(ref decl, _, _) => {
vis.check_foreign_fn(it.hir_id, decl);
vis.check_foreign_fn(abi, it.hir_id, decl);
}
hir::ForeignItemKind::Static(ref ty, _) => {
vis.check_foreign_static(it.hir_id, ty.span);
vis.check_foreign_static(abi, it.hir_id, ty.span);
}
hir::ForeignItemKind::Type => (),
}
Expand Down Expand Up @@ -1283,7 +1300,7 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions {

let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition };
if !vis.is_internal_abi(abi) {
vis.check_foreign_fn(hir_id, decl);
vis.check_foreign_fn(abi, hir_id, decl);
}
}
}
Expand Down
6 changes: 6 additions & 0 deletions src/test/ui/lint/lint-ctypes-enum.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -69,4 +69,10 @@ extern {
fn no_result(x: Result<(), num::NonZeroI32>); //~ ERROR `extern` block uses type
}

// The u128/i128 is well defined for the SystemV ABI
extern "sysv64" {
fn good_nonzero_u128(x: Option<num::NonZeroU128>);
fn good_nonzero_i128(x: Option<num::NonZeroI128>);
}

pub fn main() {}
4 changes: 4 additions & 0 deletions src/test/ui/lint/lint-ctypes-fn.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,10 @@ pub extern "C" fn i128_type(p: i128) { }
pub extern "C" fn u128_type(p: u128) { }
//~^ ERROR uses type `u128`

pub extern "sysv64" fn good_i128_type(p: i128) { }

pub extern "sysv64" fn good_u128_type(p: u128) { }

pub extern "C" fn tuple_type(p: (i32, i32)) { }
//~^ ERROR uses type `(i32, i32)`

Expand Down
24 changes: 12 additions & 12 deletions src/test/ui/lint/lint-ctypes-fn.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ LL | pub extern "C" fn u128_type(p: u128) { }
= note: 128-bit integers don't currently have a known stable ABI

error: `extern` fn uses type `(i32, i32)`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:86:33
--> $DIR/lint-ctypes-fn.rs:90:33
|
LL | pub extern "C" fn tuple_type(p: (i32, i32)) { }
| ^^^^^^^^^^ not FFI-safe
Expand All @@ -56,7 +56,7 @@ LL | pub extern "C" fn tuple_type(p: (i32, i32)) { }
= note: tuples have unspecified layout

error: `extern` fn uses type `(i32, i32)`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:89:34
--> $DIR/lint-ctypes-fn.rs:93:34
|
LL | pub extern "C" fn tuple_type2(p: I32Pair) { }
| ^^^^^^^ not FFI-safe
Expand All @@ -65,7 +65,7 @@ LL | pub extern "C" fn tuple_type2(p: I32Pair) { }
= note: tuples have unspecified layout

error: `extern` fn uses type `ZeroSize`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:92:32
--> $DIR/lint-ctypes-fn.rs:96:32
|
LL | pub extern "C" fn zero_size(p: ZeroSize) { }
| ^^^^^^^^ not FFI-safe
Expand All @@ -79,7 +79,7 @@ LL | pub struct ZeroSize;
| ^^^^^^^^^^^^^^^^^^^^

error: `extern` fn uses type `ZeroSizeWithPhantomData`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:95:40
--> $DIR/lint-ctypes-fn.rs:99:40
|
LL | pub extern "C" fn zero_size_phantom(p: ZeroSizeWithPhantomData) { }
| ^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
Expand All @@ -92,15 +92,15 @@ LL | pub struct ZeroSizeWithPhantomData(PhantomData<i32>);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: `extern` fn uses type `PhantomData<bool>`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:98:51
--> $DIR/lint-ctypes-fn.rs:102:51
|
LL | pub extern "C" fn zero_size_phantom_toplevel() -> PhantomData<bool> {
| ^^^^^^^^^^^^^^^^^ not FFI-safe
|
= note: composed only of `PhantomData`

error: `extern` fn uses type `fn()`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:103:30
--> $DIR/lint-ctypes-fn.rs:107:30
|
LL | pub extern "C" fn fn_type(p: RustFn) { }
| ^^^^^^ not FFI-safe
Expand All @@ -109,7 +109,7 @@ LL | pub extern "C" fn fn_type(p: RustFn) { }
= note: this function pointer has Rust-specific calling convention

error: `extern` fn uses type `fn()`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:106:31
--> $DIR/lint-ctypes-fn.rs:110:31
|
LL | pub extern "C" fn fn_type2(p: fn()) { }
| ^^^^ not FFI-safe
Expand All @@ -118,15 +118,15 @@ LL | pub extern "C" fn fn_type2(p: fn()) { }
= note: this function pointer has Rust-specific calling convention

error: `extern` fn uses type `i128`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:111:39
--> $DIR/lint-ctypes-fn.rs:115:39
|
LL | pub extern "C" fn transparent_i128(p: TransparentI128) { }
| ^^^^^^^^^^^^^^^ not FFI-safe
|
= note: 128-bit integers don't currently have a known stable ABI

error: `extern` fn uses type `str`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:114:38
--> $DIR/lint-ctypes-fn.rs:118:38
|
LL | pub extern "C" fn transparent_str(p: TransparentStr) { }
| ^^^^^^^^^^^^^^ not FFI-safe
Expand All @@ -135,15 +135,15 @@ LL | pub extern "C" fn transparent_str(p: TransparentStr) { }
= note: string slices have no C equivalent

error: `extern` fn uses type `PhantomData<bool>`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:160:43
--> $DIR/lint-ctypes-fn.rs:164:43
|
LL | pub extern "C" fn unused_generic2<T>() -> PhantomData<bool> {
| ^^^^^^^^^^^^^^^^^ not FFI-safe
|
= note: composed only of `PhantomData`

error: `extern` fn uses type `Vec<T>`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:173:39
--> $DIR/lint-ctypes-fn.rs:177:39
|
LL | pub extern "C" fn used_generic4<T>(x: Vec<T>) { }
| ^^^^^^ not FFI-safe
Expand All @@ -152,7 +152,7 @@ LL | pub extern "C" fn used_generic4<T>(x: Vec<T>) { }
= note: this struct has unspecified layout

error: `extern` fn uses type `Vec<T>`, which is not FFI-safe
--> $DIR/lint-ctypes-fn.rs:176:41
--> $DIR/lint-ctypes-fn.rs:180:41
|
LL | pub extern "C" fn used_generic5<T>() -> Vec<T> {
| ^^^^^^ not FFI-safe
Expand Down
9 changes: 9 additions & 0 deletions src/test/ui/lint/lint-ctypes.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,15 @@ extern {

}

// The u128/i128 is well defined for the SystemV ABI
extern "sysv64" {
pub fn good_i128_type(p: i128);
pub fn good_u128_type(p: u128);

pub static good_static_u128_type: u128;
pub static good_static_u128_array_type: [u128; 16];
}

#[allow(improper_ctypes)]
extern {
pub fn good19(_: &String);
Expand Down