From 26ac3194d155884f3a97f4d8295825ec6705b6ff Mon Sep 17 00:00:00 2001 From: pca006132 Date: Thu, 2 Jul 2020 10:08:16 +0800 Subject: [PATCH] Exception handling: copied eh_artiq from current artiq firmware. --- src/runtime/src/eh_artiq.rs | 203 ++++++++++++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 src/runtime/src/eh_artiq.rs diff --git a/src/runtime/src/eh_artiq.rs b/src/runtime/src/eh_artiq.rs new file mode 100644 index 0000000..8bfc171 --- /dev/null +++ b/src/runtime/src/eh_artiq.rs @@ -0,0 +1,203 @@ +// Portions of the code in this file are derived from code by: +// +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file 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, non_camel_case_types)] + +use core::{ptr, mem}; +use cslice::CSlice; +use unwind as uw; +use libc::{c_int, c_void}; + +use eh::dwarf::{self, EHAction}; + +type _Unwind_Stop_Fn = extern "C" fn(version: c_int, + actions: uw::_Unwind_Action, + exception_class: uw::_Unwind_Exception_Class, + exception_object: *mut uw::_Unwind_Exception, + context: *mut uw::_Unwind_Context, + stop_parameter: *mut c_void) + -> uw::_Unwind_Reason_Code; +extern { + fn _Unwind_ForcedUnwind(exception: *mut uw::_Unwind_Exception, + stop_fn: _Unwind_Stop_Fn, + stop_parameter: *mut c_void) -> uw::_Unwind_Reason_Code; +} + +#[repr(C)] +#[derive(Clone, Copy)] +pub struct Exception<'a> { + pub name: CSlice<'a, u8>, + pub file: CSlice<'a, u8>, + pub line: u32, + pub column: u32, + pub function: CSlice<'a, u8>, + pub message: CSlice<'a, u8>, + pub param: [i64; 3] +} + +const EXCEPTION_CLASS: uw::_Unwind_Exception_Class = 0x4d_4c_42_53_41_52_54_51; /* 'MLBSARTQ' */ + +const MAX_BACKTRACE_SIZE: usize = 128; + +#[repr(C)] +struct ExceptionInfo { + uw_exception: uw::_Unwind_Exception, + exception: Option>, + handled: bool, + backtrace: [usize; MAX_BACKTRACE_SIZE], + backtrace_size: usize +} + +#[cfg(target_arch = "x86_64")] +const UNWIND_DATA_REG: (i32, i32) = (0, 1); // RAX, RDX + +#[cfg(any(target_arch = "or1k"))] +const UNWIND_DATA_REG: (i32, i32) = (3, 4); // R3, R4 + +#[export_name="__artiq_personality"] +pub extern fn personality(version: c_int, + actions: uw::_Unwind_Action, + uw_exception_class: uw::_Unwind_Exception_Class, + uw_exception: *mut uw::_Unwind_Exception, + context: *mut uw::_Unwind_Context) + -> uw::_Unwind_Reason_Code { + unsafe { + if version != 1 || uw_exception_class != EXCEPTION_CLASS { + return uw::_URC_FATAL_PHASE1_ERROR + } + + let lsda = uw::_Unwind_GetLanguageSpecificData(context) as *const u8; + let ip = uw::_Unwind_GetIP(context) - 1; + let func_start = uw::_Unwind_GetRegionStart(context); + + let exception_info = &mut *(uw_exception as *mut ExceptionInfo); + let exception = &exception_info.exception.unwrap(); + + let eh_action = dwarf::find_eh_action(lsda, func_start, ip, exception.name); + if actions as u32 & uw::_UA_SEARCH_PHASE as u32 != 0 { + match eh_action { + EHAction::None | + EHAction::Cleanup(_) => return uw::_URC_CONTINUE_UNWIND, + EHAction::Catch(_) => return uw::_URC_HANDLER_FOUND, + EHAction::Terminate => return uw::_URC_FATAL_PHASE1_ERROR, + } + } else { + match eh_action { + EHAction::None => return uw::_URC_CONTINUE_UNWIND, + EHAction::Cleanup(lpad) | + EHAction::Catch(lpad) => { + if actions as u32 & uw::_UA_HANDLER_FRAME as u32 != 0 { + exception_info.handled = true + } + + // Pass a pair of the unwinder exception and ARTIQ exception + // (which immediately follows). + uw::_Unwind_SetGR(context, UNWIND_DATA_REG.0, + uw_exception as uw::_Unwind_Word); + uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, + exception as *const _ as uw::_Unwind_Word); + uw::_Unwind_SetIP(context, lpad); + return uw::_URC_INSTALL_CONTEXT; + } + EHAction::Terminate => return uw::_URC_FATAL_PHASE2_ERROR, + } + } + } +} + +extern fn cleanup(_unwind_code: uw::_Unwind_Reason_Code, + uw_exception: *mut uw::_Unwind_Exception) { + unsafe { + let exception_info = &mut *(uw_exception as *mut ExceptionInfo); + + exception_info.exception = None; + } +} + +extern fn uncaught_exception(_version: c_int, + actions: uw::_Unwind_Action, + _uw_exception_class: uw::_Unwind_Exception_Class, + uw_exception: *mut uw::_Unwind_Exception, + context: *mut uw::_Unwind_Context, + _stop_parameter: *mut c_void) + -> uw::_Unwind_Reason_Code { + unsafe { + let exception_info = &mut *(uw_exception as *mut ExceptionInfo); + + if exception_info.backtrace_size < exception_info.backtrace.len() { + let ip = uw::_Unwind_GetIP(context); + exception_info.backtrace[exception_info.backtrace_size] = ip; + exception_info.backtrace_size += 1; + } + + if actions as u32 & uw::_UA_END_OF_STACK as u32 != 0 { + ::terminate(&exception_info.exception.unwrap(), + exception_info.backtrace[..exception_info.backtrace_size].as_mut()) + } else { + uw::_URC_NO_REASON + } + } +} + +// We can unfortunately not use mem::zeroed in a static, so Option<> is used as a workaround. +// See https://github.com/rust-lang/rust/issues/39498. +static mut INFLIGHT: ExceptionInfo = ExceptionInfo { + uw_exception: uw::_Unwind_Exception { + exception_class: EXCEPTION_CLASS, + exception_cleanup: cleanup, + private: [0; uw::unwinder_private_data_size], + }, + exception: None, + handled: true, + backtrace: [0; MAX_BACKTRACE_SIZE], + backtrace_size: 0 +}; + +#[export_name="__artiq_raise"] +#[unwind(allowed)] +pub unsafe extern fn raise(exception: *const Exception) -> ! { + // Zing! The Exception<'a> to Exception<'static> transmute is not really sound in case + // the exception is ever captured. Fortunately, they currently aren't, and we save + // on the hassle of having to allocate exceptions somewhere except on stack. + INFLIGHT.exception = Some(mem::transmute::>(*exception)); + INFLIGHT.handled = false; + + let result = uw::_Unwind_RaiseException(&mut INFLIGHT.uw_exception); + assert!(result == uw::_URC_END_OF_STACK); + + INFLIGHT.backtrace_size = 0; + let _result = _Unwind_ForcedUnwind(&mut INFLIGHT.uw_exception, + uncaught_exception, ptr::null_mut()); + unreachable!() +} + +#[export_name="__artiq_reraise"] +#[unwind(allowed)] +pub unsafe extern fn reraise() -> ! { + use cslice::AsCSlice; + + if INFLIGHT.handled { + match INFLIGHT.exception { + Some(ref exception) => raise(exception), + None => raise(&Exception { + name: "0:artiq.coredevice.exceptions.RuntimeError".as_c_slice(), + file: file!().as_c_slice(), + line: line!(), + column: column!(), + // https://github.com/rust-lang/rfcs/pull/1719 + function: "__artiq_reraise".as_c_slice(), + message: "No active exception to reraise".as_c_slice(), + param: [0, 0, 0] + }) + } + } else { + uw::_Unwind_Resume(&mut INFLIGHT.uw_exception) + } +}