diff options
Diffstat (limited to 'compiler/rustc_middle/src/ty/layout.rs')
| -rw-r--r-- | compiler/rustc_middle/src/ty/layout.rs | 36 |
1 files changed, 1 insertions, 35 deletions
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index 3d397b6b37e..f608b02f42c 100644 --- a/compiler/rustc_middle/src/ty/layout.rs +++ b/compiler/rustc_middle/src/ty/layout.rs @@ -1182,37 +1182,6 @@ pub fn fn_can_unwind(tcx: TyCtxt<'_>, fn_def_id: Option<DefId>, abi: SpecAbi) -> // ABIs have such an option. Otherwise the only other thing here is Rust // itself, and those ABIs are determined by the panic strategy configured // for this compilation. - // - // Unfortunately at this time there's also another caveat. Rust [RFC - // 2945][rfc] has been accepted and is in the process of being implemented - // and stabilized. In this interim state we need to deal with historical - // rustc behavior as well as plan for future rustc behavior. - // - // Historically functions declared with `extern "C"` were marked at the - // codegen layer as `nounwind`. This happened regardless of `panic=unwind` - // or not. This is UB for functions in `panic=unwind` mode that then - // actually panic and unwind. Note that this behavior is true for both - // externally declared functions as well as Rust-defined function. - // - // To fix this UB rustc would like to change in the future to catch unwinds - // from function calls that may unwind within a Rust-defined `extern "C"` - // function and forcibly abort the process, thereby respecting the - // `nounwind` attribute emitted for `extern "C"`. This behavior change isn't - // ready to roll out, so determining whether or not the `C` family of ABIs - // unwinds is conditional not only on their definition but also whether the - // `#![feature(c_unwind)]` feature gate is active. - // - // Note that this means that unlike historical compilers rustc now, by - // default, unconditionally thinks that the `C` ABI may unwind. This will - // prevent some optimization opportunities, however, so we try to scope this - // change and only assume that `C` unwinds with `panic=unwind` (as opposed - // to `panic=abort`). - // - // Eventually the check against `c_unwind` here will ideally get removed and - // this'll be a little cleaner as it'll be a straightforward check of the - // ABI. - // - // [rfc]: https://github.com/rust-lang/rfcs/blob/master/text/2945-c-unwind-abi.md use SpecAbi::*; match abi { C { unwind } @@ -1224,10 +1193,7 @@ pub fn fn_can_unwind(tcx: TyCtxt<'_>, fn_def_id: Option<DefId>, abi: SpecAbi) -> | Thiscall { unwind } | Aapcs { unwind } | Win64 { unwind } - | SysV64 { unwind } => { - unwind - || (!tcx.features().c_unwind && tcx.sess.panic_strategy() == PanicStrategy::Unwind) - } + | SysV64 { unwind } => unwind, PtxKernel | Msp430Interrupt | X86Interrupt |