forked from M-Labs/artiq
2648b1b7a1
This also updates / is a prerequisite for updating smoltcp.
Rationale for changes made:
* compiler_builtins is now shipped in the rust prefix.
* rustc's libpanic_unwind no longer works for us because it
has a hard dependency on Box (and it's a horrible hack);
fortunately, we only ever needed a personality function
from it.
* panic and oom handlers are now set in a completely different
way.
* allocators are quite different (and finally stable).
* NLL caused internal compiler errors in runtime, so code using
NLL was rewritten to not rely on it and it was turned off.
89 lines
3.8 KiB
Rust
89 lines
3.8 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// This is the Rust personality function, adapted for use in ARTIQ. We never actually panic
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// from Rust or recover from Rust exceptions (there's nothing to catch the panics), but we
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// need a personality function to step back through Rust frames in order to make a backtrace.
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//
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// By design, this personality function is only ever called in the search phase, although
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// to keep things simple and close to upstream, it is not modified
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#![allow(private_no_mangle_fns)]
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use unwind as uw;
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use libc::{c_int, uintptr_t};
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use cslice::AsCSlice;
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use dwarf::{self, EHAction};
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// Register ids were lifted from LLVM's TargetLowering::getExceptionPointerRegister()
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// and TargetLowering::getExceptionSelectorRegister() for each architecture,
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// then mapped to DWARF register numbers via register definition tables
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// (typically <arch>RegisterInfo.td, search for "DwarfRegNum").
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// See also http://llvm.org/docs/WritingAnLLVMBackend.html#defining-a-register.
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#[cfg(target_arch = "x86")]
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const UNWIND_DATA_REG: (i32, i32) = (0, 2); // EAX, EDX
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#[cfg(target_arch = "x86_64")]
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const UNWIND_DATA_REG: (i32, i32) = (0, 1); // RAX, RDX
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#[cfg(any(target_arch = "or1k"))]
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const UNWIND_DATA_REG: (i32, i32) = (3, 4); // R3, R4
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// The following code is based on GCC's C and C++ personality routines. For reference, see:
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// https://github.com/gcc-mirror/gcc/blob/master/libstdc++-v3/libsupc++/eh_personality.cc
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// https://github.com/gcc-mirror/gcc/blob/trunk/libgcc/unwind-c.c
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#[lang = "eh_personality"]
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#[no_mangle]
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#[allow(unused)]
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unsafe extern "C" fn rust_eh_personality(version: c_int,
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actions: uw::_Unwind_Action,
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exception_class: uw::_Unwind_Exception_Class,
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exception_object: *mut uw::_Unwind_Exception,
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context: *mut uw::_Unwind_Context)
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-> uw::_Unwind_Reason_Code {
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if version != 1 {
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return uw::_URC_FATAL_PHASE1_ERROR;
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}
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let eh_action = match find_eh_action(context) {
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Ok(action) => action,
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Err(_) => return uw::_URC_FATAL_PHASE1_ERROR,
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};
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if actions as i32 & uw::_UA_SEARCH_PHASE as i32 != 0 {
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match eh_action {
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EHAction::None |
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EHAction::Cleanup(_) => return uw::_URC_CONTINUE_UNWIND,
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EHAction::Catch(_) => return uw::_URC_HANDLER_FOUND,
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EHAction::Terminate => return uw::_URC_FATAL_PHASE1_ERROR,
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}
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} else {
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match eh_action {
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EHAction::None => return uw::_URC_CONTINUE_UNWIND,
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EHAction::Cleanup(lpad) |
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EHAction::Catch(lpad) => {
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uw::_Unwind_SetGR(context, UNWIND_DATA_REG.0, exception_object as uintptr_t);
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uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, 0);
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uw::_Unwind_SetIP(context, lpad);
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return uw::_URC_INSTALL_CONTEXT;
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}
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EHAction::Terminate => return uw::_URC_FATAL_PHASE2_ERROR,
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}
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}
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}
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unsafe fn find_eh_action(context: *mut uw::_Unwind_Context)
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-> Result<EHAction, ()>
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{
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let lsda = uw::_Unwind_GetLanguageSpecificData(context) as *const u8;
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let func = uw::_Unwind_GetRegionStart(context);
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let ip = uw::_Unwind_GetIP(context);
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Ok(dwarf::find_eh_action(lsda, func, ip, [].as_c_slice()))
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}
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