8eb7f36a3b
This is duplicated in a few locations throughout the sysroot to work around issues with not exporting a macro in libstd but still wanting it available to sysroot crates to define blocks. Nowadays though we can simply depend on the `cfg-if` crate on crates.io, allowing us to use it from there!
100 lines
3.2 KiB
Rust
100 lines
3.2 KiB
Rust
//! Implementation of panics via stack unwinding
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//!
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//! This crate is an implementation of panics in Rust using "most native" stack
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//! unwinding mechanism of the platform this is being compiled for. This
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//! essentially gets categorized into three buckets currently:
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//!
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//! 1. MSVC targets use SEH in the `seh.rs` file.
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//! 2. The 64-bit MinGW target half-uses SEH and half-use gcc-like information
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//! in the `seh64_gnu.rs` module.
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//! 3. All other targets use libunwind/libgcc in the `gcc/mod.rs` module.
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//!
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//! More documentation about each implementation can be found in the respective
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//! module.
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#![no_std]
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#![unstable(feature = "panic_unwind", issue = "32837")]
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#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
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issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
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#![deny(rust_2018_idioms)]
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#![feature(core_intrinsics)]
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#![feature(lang_items)]
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#![feature(libc)]
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#![feature(nll)]
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#![feature(panic_unwind)]
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#![feature(raw)]
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#![feature(staged_api)]
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#![feature(std_internals)]
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#![feature(unwind_attributes)]
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#![panic_runtime]
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#![feature(panic_runtime)]
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use alloc::boxed::Box;
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use core::intrinsics;
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use core::mem;
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use core::raw;
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use core::panic::BoxMeUp;
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cfg_if::cfg_if! {
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if #[cfg(target_os = "emscripten")] {
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#[path = "emcc.rs"]
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mod imp;
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} else if #[cfg(target_arch = "wasm32")] {
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#[path = "dummy.rs"]
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mod imp;
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} else if #[cfg(all(target_env = "msvc", target_arch = "aarch64"))] {
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#[path = "dummy.rs"]
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mod imp;
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} else if #[cfg(target_env = "msvc")] {
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#[path = "seh.rs"]
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mod imp;
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} else if #[cfg(all(windows, target_arch = "x86_64", target_env = "gnu"))] {
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#[path = "seh64_gnu.rs"]
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mod imp;
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} else {
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// Rust runtime's startup objects depend on these symbols, so make them public.
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#[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
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pub use imp::eh_frame_registry::*;
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#[path = "gcc.rs"]
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mod imp;
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}
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}
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mod dwarf;
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mod windows;
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// Entry point for catching an exception, implemented using the `try` intrinsic
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// in the compiler.
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//
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// The interaction between the `payload` function and the compiler is pretty
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// hairy and tightly coupled, for more information see the compiler's
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// implementation of this.
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#[no_mangle]
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pub unsafe extern "C" fn __rust_maybe_catch_panic(f: fn(*mut u8),
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data: *mut u8,
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data_ptr: *mut usize,
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vtable_ptr: *mut usize)
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-> u32 {
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let mut payload = imp::payload();
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if intrinsics::r#try(f, data, &mut payload as *mut _ as *mut _) == 0 {
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0
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} else {
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let obj = mem::transmute::<_, raw::TraitObject>(imp::cleanup(payload));
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*data_ptr = obj.data as usize;
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*vtable_ptr = obj.vtable as usize;
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1
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}
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}
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// Entry point for raising an exception, just delegates to the platform-specific
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// implementation.
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#[no_mangle]
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#[unwind(allowed)]
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pub unsafe extern "C" fn __rust_start_panic(payload: usize) -> u32 {
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let payload = payload as *mut &mut dyn BoxMeUp;
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imp::panic(Box::from_raw((*payload).box_me_up()))
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}
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