// Copyright 2015 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![allow(private_no_mangle_fns)] use prelude::v1::*; use any::Any; use sys_common::libunwind as uw; struct Exception { uwe: uw::_Unwind_Exception, cause: Option>, } pub unsafe fn panic(data: Box) -> ! { let exception: Box<_> = box Exception { uwe: uw::_Unwind_Exception { exception_class: rust_exception_class(), exception_cleanup: exception_cleanup, private: [0; uw::unwinder_private_data_size], }, cause: Some(data), }; let exception_param = Box::into_raw(exception) as *mut uw::_Unwind_Exception; let error = uw::_Unwind_RaiseException(exception_param); rtabort!("Could not unwind stack, error = {}", error as isize); extern fn exception_cleanup(_unwind_code: uw::_Unwind_Reason_Code, exception: *mut uw::_Unwind_Exception) { unsafe { let _: Box = Box::from_raw(exception as *mut Exception); } } } pub fn payload() -> *mut u8 { 0 as *mut u8 } pub unsafe fn cleanup(ptr: *mut u8) -> Box { let my_ep = ptr as *mut Exception; let cause = (*my_ep).cause.take(); uw::_Unwind_DeleteException(ptr as *mut _); cause.unwrap() } // Rust's exception class identifier. This is used by personality routines to // determine whether the exception was thrown by their own runtime. fn rust_exception_class() -> uw::_Unwind_Exception_Class { // M O Z \0 R U S T -- vendor, language 0x4d4f5a_00_52555354 } // We could implement our personality routine in pure Rust, however exception // info decoding is tedious. More importantly, personality routines have to // handle various platform quirks, which are not fun to maintain. For this // reason, we attempt to reuse personality routine of the C language: // __gcc_personality_v0. // // Since C does not support exception catching, __gcc_personality_v0 simply // always returns _URC_CONTINUE_UNWIND in search phase, and always returns // _URC_INSTALL_CONTEXT (i.e. "invoke cleanup code") in cleanup phase. // // This is pretty close to Rust's exception handling approach, except that Rust // does have a single "catch-all" handler at the bottom of each thread's stack. // So we have two versions of the personality routine: // - rust_eh_personality, used by all cleanup landing pads, which never catches, // so the behavior of __gcc_personality_v0 is perfectly adequate there, and // - rust_eh_personality_catch, used only by rust_try(), which always catches. // // See also: rustc_trans::trans::intrinsic::trans_gnu_try #[cfg(all(not(target_arch = "arm"), not(all(windows, target_arch = "x86_64")), not(test)))] pub mod eabi { use sys_common::libunwind as uw; use libc::c_int; extern { fn __gcc_personality_v0(version: c_int, actions: uw::_Unwind_Action, exception_class: uw::_Unwind_Exception_Class, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context) -> uw::_Unwind_Reason_Code; } #[lang = "eh_personality"] #[no_mangle] extern fn rust_eh_personality( version: c_int, actions: uw::_Unwind_Action, exception_class: uw::_Unwind_Exception_Class, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context ) -> uw::_Unwind_Reason_Code { unsafe { __gcc_personality_v0(version, actions, exception_class, ue_header, context) } } #[lang = "eh_personality_catch"] #[no_mangle] pub extern fn rust_eh_personality_catch( version: c_int, actions: uw::_Unwind_Action, exception_class: uw::_Unwind_Exception_Class, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context ) -> uw::_Unwind_Reason_Code { if (actions as c_int & uw::_UA_SEARCH_PHASE as c_int) != 0 { // search phase uw::_URC_HANDLER_FOUND // catch! } else { // cleanup phase unsafe { __gcc_personality_v0(version, actions, exception_class, ue_header, context) } } } } // iOS on armv7 is using SjLj exceptions and therefore requires to use // a specialized personality routine: __gcc_personality_sj0 #[cfg(all(target_os = "ios", target_arch = "arm", not(test)))] pub mod eabi { use sys_common::libunwind as uw; use libc::c_int; extern { fn __gcc_personality_sj0(version: c_int, actions: uw::_Unwind_Action, exception_class: uw::_Unwind_Exception_Class, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context) -> uw::_Unwind_Reason_Code; } #[lang = "eh_personality"] #[no_mangle] pub extern fn rust_eh_personality( version: c_int, actions: uw::_Unwind_Action, exception_class: uw::_Unwind_Exception_Class, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context ) -> uw::_Unwind_Reason_Code { unsafe { __gcc_personality_sj0(version, actions, exception_class, ue_header, context) } } #[lang = "eh_personality_catch"] #[no_mangle] pub extern fn rust_eh_personality_catch( version: c_int, actions: uw::_Unwind_Action, exception_class: uw::_Unwind_Exception_Class, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context ) -> uw::_Unwind_Reason_Code { if (actions as c_int & uw::_UA_SEARCH_PHASE as c_int) != 0 { // search phase uw::_URC_HANDLER_FOUND // catch! } else { // cleanup phase unsafe { __gcc_personality_sj0(version, actions, exception_class, ue_header, context) } } } } // ARM EHABI uses a slightly different personality routine signature, // but otherwise works the same. #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(test)))] pub mod eabi { use sys_common::libunwind as uw; use libc::c_int; extern { fn __gcc_personality_v0(state: uw::_Unwind_State, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context) -> uw::_Unwind_Reason_Code; } #[lang = "eh_personality"] #[no_mangle] extern fn rust_eh_personality( state: uw::_Unwind_State, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context ) -> uw::_Unwind_Reason_Code { unsafe { __gcc_personality_v0(state, ue_header, context) } } #[lang = "eh_personality_catch"] #[no_mangle] pub extern fn rust_eh_personality_catch( state: uw::_Unwind_State, ue_header: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context ) -> uw::_Unwind_Reason_Code { if (state as c_int & uw::_US_ACTION_MASK as c_int) == uw::_US_VIRTUAL_UNWIND_FRAME as c_int { // search phase uw::_URC_HANDLER_FOUND // catch! } else { // cleanup phase unsafe { __gcc_personality_v0(state, ue_header, context) } } } } // See docs in the `unwind` module. #[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu", not(test)))] #[lang = "eh_unwind_resume"] #[unwind] unsafe extern fn rust_eh_unwind_resume(panic_ctx: *mut u8) -> ! { uw::_Unwind_Resume(panic_ctx as *mut uw::_Unwind_Exception); } #[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))] pub mod eh_frame_registry { // The implementation of stack unwinding is (for now) deferred to libgcc_eh, however Rust // crates use these Rust-specific entry points to avoid potential clashes with GCC runtime. // See also: rtbegin.rs, `unwind` module. #[link(name = "gcc_eh")] #[cfg(not(cargobuild))] extern {} extern { fn __register_frame_info(eh_frame_begin: *const u8, object: *mut u8); fn __deregister_frame_info(eh_frame_begin: *const u8, object: *mut u8); } #[cfg(not(test))] #[no_mangle] #[unstable(feature = "libstd_sys_internals", issue = "0")] pub unsafe extern fn rust_eh_register_frames(eh_frame_begin: *const u8, object: *mut u8) { __register_frame_info(eh_frame_begin, object); } #[cfg(not(test))] #[no_mangle] #[unstable(feature = "libstd_sys_internals", issue = "0")] pub unsafe extern fn rust_eh_unregister_frames(eh_frame_begin: *const u8, object: *mut u8) { __deregister_frame_info(eh_frame_begin, object); } }