rust/tests/ui/lint/clashing-extern-fn.rs
2024-04-22 18:48:47 +02:00

439 lines
11 KiB
Rust

//@ check-pass
//@ aux-build:external_extern_fn.rs
#![crate_type = "lib"]
#![warn(clashing_extern_declarations)]
mod redeclared_different_signature {
mod a {
extern "C" {
fn clash(x: u8);
}
}
mod b {
extern "C" {
fn clash(x: u64); //~ WARN `clash` redeclared with a different signature
}
}
}
mod redeclared_same_signature {
mod a {
extern "C" {
fn no_clash(x: u8);
}
}
mod b {
extern "C" {
fn no_clash(x: u8);
}
}
}
extern crate external_extern_fn;
mod extern_no_clash {
// Should not clash with external_extern_fn::extern_fn.
extern "C" {
fn extern_fn(x: u8);
}
}
extern "C" {
fn some_other_new_name(x: i16);
#[link_name = "extern_link_name"]
fn some_new_name(x: i16);
#[link_name = "link_name_same"]
fn both_names_different(x: i16);
}
fn link_name_clash() {
extern "C" {
fn extern_link_name(x: u32);
//~^ WARN `extern_link_name` redeclared with a different signature
#[link_name = "some_other_new_name"]
//~^ WARN `some_other_extern_link_name` redeclares `some_other_new_name` with a different
fn some_other_extern_link_name(x: u32);
#[link_name = "link_name_same"]
//~^ WARN `other_both_names_different` redeclares `link_name_same` with a different
fn other_both_names_different(x: u32);
}
}
mod a {
extern "C" {
fn different_mod(x: u8);
}
}
mod b {
extern "C" {
fn different_mod(x: u64); //~ WARN `different_mod` redeclared with a different signature
}
}
extern "C" {
fn variadic_decl(x: u8, ...);
}
fn variadic_clash() {
extern "C" {
fn variadic_decl(x: u8); //~ WARN `variadic_decl` redeclared with a different signature
}
}
#[no_mangle]
fn no_mangle_name(x: u8) {}
extern "C" {
#[link_name = "unique_link_name"]
fn link_name_specified(x: u8);
}
fn tricky_no_clash() {
extern "C" {
// Shouldn't warn, because the declaration above actually declares a different symbol (and
// Rust's name resolution rules around shadowing will handle this gracefully).
fn link_name_specified() -> u32;
// The case of a no_mangle name colliding with an extern decl (see #28179) is related but
// shouldn't be reported by ClashingExternDeclarations, because this is an example of
// unmangled name clash causing bad behaviour in functions with a defined body.
fn no_mangle_name() -> u32;
}
}
mod banana {
mod one {
#[repr(C)]
struct Banana {
weight: u32,
length: u16,
}
extern "C" {
fn weigh_banana(count: *const Banana) -> u64;
}
}
mod two {
#[repr(C)]
struct Banana {
weight: u32,
length: u16,
} // note: distinct type
// This should not trigger the lint because two::Banana is structurally equivalent to
// one::Banana.
extern "C" {
fn weigh_banana(count: *const Banana) -> u64;
}
}
mod three {
// This _should_ trigger the lint, because repr(packed) should generate a struct that has a
// different layout.
#[repr(packed)]
struct Banana {
weight: u32,
length: u16,
}
#[allow(improper_ctypes)]
extern "C" {
fn weigh_banana(count: *const Banana) -> u64;
//~^ WARN `weigh_banana` redeclared with a different signature
}
}
}
mod sameish_members {
mod a {
#[repr(C)]
struct Point {
x: i16,
y: i16,
}
extern "C" {
fn draw_point(p: Point);
}
}
mod b {
#[repr(C)]
struct Point {
coordinates: [i16; 2],
}
// It's possible we are overconservative for this case, as accessing the elements of the
// coordinates array might end up correctly accessing `.x` and `.y`. However, this may not
// always be the case, for every architecture and situation. This is also a really odd
// thing to do anyway.
extern "C" {
fn draw_point(p: Point);
//~^ WARN `draw_point` redeclared with a different signature
}
}
}
mod same_sized_members_clash {
mod a {
#[repr(C)]
struct Point3 {
x: f32,
y: f32,
z: f32,
}
extern "C" {
fn origin() -> Point3;
}
}
mod b {
#[repr(C)]
struct Point3 {
x: i32,
y: i32,
z: i32, // NOTE: Incorrectly redeclared as i32
}
extern "C" {
fn origin() -> Point3; //~ WARN `origin` redeclared with a different signature
}
}
}
mod transparent {
#[repr(transparent)]
struct T(usize);
mod a {
use super::T;
extern "C" {
fn transparent() -> T;
fn transparent_incorrect() -> T;
}
}
mod b {
extern "C" {
// Shouldn't warn here, because repr(transparent) guarantees that T's layout is the
// same as just the usize.
fn transparent() -> usize;
// Should warn, because there's a signedness conversion here:
fn transparent_incorrect() -> isize;
//~^ WARN `transparent_incorrect` redeclared with a different signature
}
}
}
#[allow(improper_ctypes)]
mod zst {
mod transparent {
#[repr(transparent)]
struct TransparentZst(());
extern "C" {
fn zst() -> ();
fn transparent_zst() -> TransparentZst;
}
}
mod not_transparent {
struct NotTransparentZst(());
extern "C" {
// These shouldn't warn since all return types are zero sized
fn zst() -> NotTransparentZst;
fn transparent_zst() -> NotTransparentZst;
}
}
}
mod missing_return_type {
mod a {
extern "C" {
fn missing_return_type() -> usize;
}
}
mod b {
extern "C" {
// This should output a warning because we can't assume that the first declaration is
// the correct one -- if this one is the correct one, then calling the usize-returning
// version would allow reads into uninitialised memory.
fn missing_return_type();
//~^ WARN `missing_return_type` redeclared with a different signature
}
}
}
mod non_zero_and_non_null {
mod a {
extern "C" {
fn non_zero_usize() -> core::num::NonZero<usize>;
fn non_null_ptr() -> core::ptr::NonNull<usize>;
}
}
mod b {
extern "C" {
// If there's a clash in either of these cases you're either gaining an incorrect
// invariant that the value is non-zero, or you're missing out on that invariant. Both
// cases are warning for, from both a caller-convenience and optimisation perspective.
fn non_zero_usize() -> usize;
//~^ WARN `non_zero_usize` redeclared with a different signature
fn non_null_ptr() -> *const usize;
//~^ WARN `non_null_ptr` redeclared with a different signature
}
}
}
// See #75739
mod non_zero_transparent {
mod a1 {
extern "C" {
fn f1() -> std::num::NonZero<usize>;
}
}
mod b1 {
#[repr(transparent)]
struct X(std::num::NonZero<usize>);
extern "C" {
fn f1() -> X;
}
}
mod a2 {
extern "C" {
fn f2() -> std::num::NonZero<usize>;
}
}
mod b2 {
#[repr(transparent)]
struct X1(std::num::NonZero<usize>);
#[repr(transparent)]
struct X(X1);
extern "C" {
// Same case as above, but with two layers of newtyping.
fn f2() -> X;
}
}
mod a3 {
#[repr(transparent)]
struct X(core::ptr::NonNull<i32>);
extern "C" {
fn f3() -> X;
}
}
mod b3 {
extern "C" {
fn f3() -> core::ptr::NonNull<i32>;
}
}
mod a4 {
#[repr(transparent)]
enum E {
X(std::num::NonZero<usize>),
}
extern "C" {
fn f4() -> E;
}
}
mod b4 {
extern "C" {
fn f4() -> std::num::NonZero<usize>;
}
}
}
mod null_optimised_enums {
mod a {
extern "C" {
fn option_non_zero_usize() -> usize;
fn option_non_zero_isize() -> isize;
fn option_non_null_ptr() -> *const usize;
fn option_non_zero_usize_incorrect() -> usize;
fn option_non_null_ptr_incorrect() -> *const usize;
}
}
mod b {
extern "C" {
// This should be allowed, because these conversions are guaranteed to be FFI-safe (see
// #60300)
fn option_non_zero_usize() -> Option<core::num::NonZero<usize>>;
fn option_non_zero_isize() -> Option<core::num::NonZero<isize>>;
fn option_non_null_ptr() -> Option<core::ptr::NonNull<usize>>;
// However, these should be incorrect (note isize instead of usize)
fn option_non_zero_usize_incorrect() -> isize;
//~^ WARN `option_non_zero_usize_incorrect` redeclared with a different signature
fn option_non_null_ptr_incorrect() -> *const isize;
//~^ WARN `option_non_null_ptr_incorrect` redeclared with a different signature
}
}
}
#[allow(improper_ctypes)]
mod unknown_layout {
mod a {
extern "C" {
pub fn generic(l: Link<u32>);
}
pub struct Link<T> {
pub item: T,
pub next: *const Link<T>,
}
}
mod b {
extern "C" {
pub fn generic(l: Link<u32>);
}
pub struct Link<T> {
pub item: T,
pub next: *const Link<T>,
}
}
}
mod hidden_niche {
mod a {
extern "C" {
fn hidden_niche_transparent() -> usize;
fn hidden_niche_transparent_no_niche() -> usize;
fn hidden_niche_unsafe_cell() -> usize;
}
}
mod b {
use std::cell::UnsafeCell;
use std::num::NonZero;
#[repr(transparent)]
struct Transparent {
x: NonZero<usize>,
}
#[repr(transparent)]
struct TransparentNoNiche {
y: UnsafeCell<NonZero<usize>>,
}
extern "C" {
fn hidden_niche_transparent() -> Option<Transparent>;
fn hidden_niche_transparent_no_niche() -> Option<TransparentNoNiche>;
//~^ WARN redeclared with a different signature
//~| WARN block uses type `Option<TransparentNoNiche>`, which is not FFI-safe
fn hidden_niche_unsafe_cell() -> Option<UnsafeCell<NonZero<usize>>>;
//~^ WARN redeclared with a different signature
//~| WARN block uses type `Option<UnsafeCell<NonZero<usize>>>`, which is not FFI-safe
}
}
}