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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/structs-enums/enum-clike-ffi-as-int.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/structs-enums/enum-clike-ffi-as-int.rs')
-rw-r--r-- | src/test/ui/structs-enums/enum-clike-ffi-as-int.rs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/test/ui/structs-enums/enum-clike-ffi-as-int.rs b/src/test/ui/structs-enums/enum-clike-ffi-as-int.rs new file mode 100644 index 000000000..e2b2b43de --- /dev/null +++ b/src/test/ui/structs-enums/enum-clike-ffi-as-int.rs @@ -0,0 +1,33 @@ +// run-pass +#![allow(dead_code)] + +/*! + * C-like enums have to be represented as LLVM ints, not wrapped in a + * struct, because it's important for the FFI that they interoperate + * with C integers/enums, and the ABI can treat structs differently. + * For example, on i686-linux-gnu, a struct return value is passed by + * storing to a hidden out parameter, whereas an integer would be + * returned in a register. + * + * This test just checks that the ABIs for the enum and the plain + * integer are compatible, rather than actually calling C code. + * The unused parameter to `foo` is to increase the likelihood of + * crashing if something goes wrong here. + */ + +#[repr(u32)] +enum Foo { + A = 0, + B = 23 +} + +#[inline(never)] +extern "C" fn foo(_x: usize) -> Foo { Foo::B } + +pub fn main() { + unsafe { + let f: extern "C" fn(usize) -> u32 = + ::std::mem::transmute(foo as extern "C" fn(usize) -> Foo); + assert_eq!(f(0xDEADBEEF), Foo::B as u32); + } +} |