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Exception handling: copied eh_artiq from current artiq firmware.

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pca006132 2020-07-02 10:08:16 +08:00
parent 0a35f68562
commit 26ac3194d1
1 changed files with 203 additions and 0 deletions
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src/runtime/src/eh_artiq.rs Normal file
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// 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 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, 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<Exception<'static>>,
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, Exception<'static>>(*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)
}
}