mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Auto merge of #132200 - Mark-Simulacrum:strengthen-cross-lang, r=RalfJung

Browse Source 
Make clearer that guarantees in ABI compatibility are for Rust only

cc https://github.com/rust-lang/rust/pull/132136#issuecomment-2439737631 -- it looks like we already had a note that I missed in my initial look here, but this goes further to emphasize the guarantees, including uplifting it to the top of the general documentation.

r? `@RalfJung`
This commit is contained in:
bors 2024-10-28 04:47:06 +00:00
commit 6929a48275
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
library/core/src/primitive_docs.rs
View File

@ -1612,6 +1612,9 @@ mod prim_ref {}
/// pointers, make your type [`Option<fn()>`](core::option#options-and-pointers-nullable-pointers)
/// with your required signature.
///
/// Note that FFI requires additional care to ensure that the ABI for both sides of the call match.
/// The exact requirements are not currently documented.
///
/// ### Safety
///
/// Plain function pointers are obtained by casting either plain functions, or closures that don't
@ -1750,8 +1753,13 @@ mod prim_ref {}
/// is also used rarely. So, most likely you do not have to worry about ABI compatibility.
///
/// But assuming such circumstances, what are the rules? For this section, we are only considering
/// the ABI of direct Rust-to-Rust calls, not linking in general -- once functions are imported via
/// `extern` blocks, there are more things to consider that we do not go into here.
/// the ABI of direct Rust-to-Rust calls (with both definition and callsite visible to the
/// Rust compiler), not linking in general -- once functions are imported via `extern` blocks, there
/// are more things to consider that we do not go into here. Note that this also applies to
/// passing/calling functions across language boundaries via function pointers.
///
/// **Nothing in this section should be taken as a guarantee for non-Rust-to-Rust calls, even with
/// types from `core::ffi` or `libc`**.
///
/// For two signatures to be considered *ABI-compatible*, they must use a compatible ABI string,
/// must take the same number of arguments, the individual argument types and the return types must