1 files changed, 110 insertions, 0 deletions
diff --git a/library/panic_unwind/src/lib.rs b/library/panic_unwind/src/lib.rs
new file mode 100644
index 000000000..f9acb42c4
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+++ b/library/panic_unwind/src/lib.rs
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+//! Implementation of panics via stack unwinding
+//!
+//! This crate is an implementation of panics in Rust using "most native" stack
+//! unwinding mechanism of the platform this is being compiled for. This
+//! essentially gets categorized into three buckets currently:
+//!
+//! 1. MSVC targets use SEH in the `seh.rs` file.
+//! 2. Emscripten uses C++ exceptions in the `emcc.rs` file.
+//! 3. All other targets use libunwind/libgcc in the `gcc.rs` file.
+//!
+//! More documentation about each implementation can be found in the respective
+//! module.
+
+#![no_std]
+#![unstable(feature = "panic_unwind", issue = "32837")]
+#![doc(issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
+#![feature(core_intrinsics)]
+#![feature(lang_items)]
+#![feature(panic_unwind)]
+#![feature(staged_api)]
+#![feature(std_internals)]
+#![feature(abi_thiscall)]
+#![feature(rustc_attrs)]
+#![panic_runtime]
+#![feature(panic_runtime)]
+#![feature(c_unwind)]
+// `real_imp` is unused with Miri, so silence warnings.
+#![cfg_attr(miri, allow(dead_code))]
+
+use alloc::boxed::Box;
+use core::any::Any;
+use core::panic::BoxMeUp;
+
+cfg_if::cfg_if! {
+    if #[cfg(target_os = "emscripten")] {
+        #[path = "emcc.rs"]
+        mod real_imp;
+    } else if #[cfg(target_os = "hermit")] {
+        #[path = "hermit.rs"]
+        mod real_imp;
+    } else if #[cfg(target_os = "l4re")] {
+        // L4Re is unix family but does not yet support unwinding.
+        #[path = "dummy.rs"]
+        mod real_imp;
+    } else if #[cfg(target_env = "msvc")] {
+        #[path = "seh.rs"]
+        mod real_imp;
+    } else if #[cfg(any(
+        all(target_family = "windows", target_env = "gnu"),
+        target_os = "psp",
+        target_os = "solid_asp3",
+        all(target_family = "unix", not(target_os = "espidf")),
+        all(target_vendor = "fortanix", target_env = "sgx"),
+    ))] {
+        // Rust runtime's startup objects depend on these symbols, so make them public.
+        #[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
+        pub use real_imp::eh_frame_registry::*;
+        #[path = "gcc.rs"]
+        mod real_imp;
+    } else {
+        // Targets that don't support unwinding.
+        // - family=wasm
+        // - os=none ("bare metal" targets)
+        // - os=uefi
+        // - os=espidf
+        // - nvptx64-nvidia-cuda
+        // - arch=avr
+        #[path = "dummy.rs"]
+        mod real_imp;
+    }
+}
+
+cfg_if::cfg_if! {
+    if #[cfg(miri)] {
+        // Use the Miri runtime.
+        // We still need to also load the normal runtime above, as rustc expects certain lang
+        // items from there to be defined.
+        #[path = "miri.rs"]
+        mod imp;
+    } else {
+        // Use the real runtime.
+        use real_imp as imp;
+    }
+}
+
+extern "C" {
+    /// Handler in libstd called when a panic object is dropped outside of
+    /// `catch_unwind`.
+    fn __rust_drop_panic() -> !;
+
+    /// Handler in libstd called when a foreign exception is caught.
+    fn __rust_foreign_exception() -> !;
+}
+
+mod dwarf;
+
+#[rustc_std_internal_symbol]
+#[allow(improper_ctypes_definitions)]
+pub unsafe extern "C" fn __rust_panic_cleanup(payload: *mut u8) -> *mut (dyn Any + Send + 'static) {
+    Box::into_raw(imp::cleanup(payload))
+}
+
+// Entry point for raising an exception, just delegates to the platform-specific
+// implementation.
+#[rustc_std_internal_symbol]
+pub unsafe fn __rust_start_panic(payload: *mut &mut dyn BoxMeUp) -> u32 {
+    let payload = Box::from_raw((*payload).take_box());
+
+    imp::panic(payload)
+}