rust/compiler/rustc_hir_analysis
bors dfa88b328f Auto merge of #120500 - oli-obk:intrinsics2.0, r=WaffleLapkin
Implement intrinsics with fallback bodies

fixes #93145 (though we can port many more intrinsics)
cc #63585

The way this works is that the backend logic for generating custom code for intrinsics has been made fallible. The only failure path is "this intrinsic is unknown". The `Instance` (that was `InstanceDef::Intrinsic`) then gets converted to `InstanceDef::Item`, which represents the fallback body. A regular function call to that body is then codegenned. This is currently implemented for

* codegen_ssa (so llvm and gcc)
* codegen_cranelift

other backends will need to adjust, but they can just keep doing what they were doing if they prefer (though adding new intrinsics to the compiler will then require them to implement them, instead of getting the fallback body).

cc `@scottmcm` `@WaffleLapkin`

### todo

* [ ] miri support
* [x] default intrinsic name to name of function instead of requiring it to be specified in attribute
* [x] make sure that the bodies are always available (must be collected for metadata)
2024-02-16 09:53:01 +00:00
..
src Auto merge of #120500 - oli-obk:intrinsics2.0, r=WaffleLapkin 2024-02-16 09:53:01 +00:00
Cargo.toml Use zip_eq to enforce that things being zipped have equal sizes 2024-01-14 20:01:12 +00:00
messages.ftl Rollup merge of #120958 - ShoyuVanilla:remove-subst, r=oli-obk 2024-02-12 23:18:54 +01:00
README.md rustc_typeck to rustc_hir_analysis 2022-09-27 10:37:23 +02:00

For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.