diff --git a/std/src/sys/personality/gcc.rs b/std/src/sys/personality/gcc.rs index 0dc53550ca943..5542cf03d20c1 100644 --- a/std/src/sys/personality/gcc.rs +++ b/std/src/sys/personality/gcc.rs @@ -35,6 +35,7 @@ //! //! Once stack has been unwound down to the handler frame level, unwinding stops //! and the last personality routine transfers control to the catch block. +#![forbid(unsafe_op_in_unsafe_fn)] use super::dwarf::eh::{self, EHAction, EHContext}; use crate::ffi::c_int; @@ -92,7 +93,11 @@ const UNWIND_DATA_REG: (i32, i32) = (4, 5); // a0, a1 // https://github.com/gcc-mirror/gcc/blob/trunk/libgcc/unwind-c.c cfg_if::cfg_if! { - if #[cfg(all(not(all(target_vendor = "apple", not(target_os = "watchos"))), target_arch = "arm", not(target_os = "netbsd")))] { + if #[cfg(all( + target_arch = "arm", + not(all(target_vendor = "apple", not(target_os = "watchos"))), + not(target_os = "netbsd"), + ))] { // ARM EHABI personality routine. // https://web.archive.org/web/20190728160938/https://infocenter.arm.com/help/topic/com.arm.doc.ihi0038b/IHI0038B_ehabi.pdf // @@ -104,90 +109,94 @@ cfg_if::cfg_if! { exception_object: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context, ) -> uw::_Unwind_Reason_Code { - let state = state as c_int; - let action = state & uw::_US_ACTION_MASK as c_int; - let search_phase = if action == uw::_US_VIRTUAL_UNWIND_FRAME as c_int { - // Backtraces on ARM will call the personality routine with - // state == _US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND. In those cases - // we want to continue unwinding the stack, otherwise all our backtraces - // would end at __rust_try - if state & uw::_US_FORCE_UNWIND as c_int != 0 { + unsafe { + let state = state as c_int; + let action = state & uw::_US_ACTION_MASK as c_int; + let search_phase = if action == uw::_US_VIRTUAL_UNWIND_FRAME as c_int { + // Backtraces on ARM will call the personality routine with + // state == _US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND. In those cases + // we want to continue unwinding the stack, otherwise all our backtraces + // would end at __rust_try + if state & uw::_US_FORCE_UNWIND as c_int != 0 { + return continue_unwind(exception_object, context); + } + true + } else if action == uw::_US_UNWIND_FRAME_STARTING as c_int { + false + } else if action == uw::_US_UNWIND_FRAME_RESUME as c_int { return continue_unwind(exception_object, context); - } - true - } else if action == uw::_US_UNWIND_FRAME_STARTING as c_int { - false - } else if action == uw::_US_UNWIND_FRAME_RESUME as c_int { - return continue_unwind(exception_object, context); - } else { - return uw::_URC_FAILURE; - }; + } else { + return uw::_URC_FAILURE; + }; - // The DWARF unwinder assumes that _Unwind_Context holds things like the function - // and LSDA pointers, however ARM EHABI places them into the exception object. - // To preserve signatures of functions like _Unwind_GetLanguageSpecificData(), which - // take only the context pointer, GCC personality routines stash a pointer to - // exception_object in the context, using location reserved for ARM's - // "scratch register" (r12). - uw::_Unwind_SetGR(context, uw::UNWIND_POINTER_REG, exception_object as uw::_Unwind_Ptr); - // ...A more principled approach would be to provide the full definition of ARM's - // _Unwind_Context in our libunwind bindings and fetch the required data from there - // directly, bypassing DWARF compatibility functions. + // The DWARF unwinder assumes that _Unwind_Context holds things like the function + // and LSDA pointers, however ARM EHABI places them into the exception object. + // To preserve signatures of functions like _Unwind_GetLanguageSpecificData(), which + // take only the context pointer, GCC personality routines stash a pointer to + // exception_object in the context, using location reserved for ARM's + // "scratch register" (r12). + uw::_Unwind_SetGR(context, uw::UNWIND_POINTER_REG, exception_object as uw::_Unwind_Ptr); + // ...A more principled approach would be to provide the full definition of ARM's + // _Unwind_Context in our libunwind bindings and fetch the required data from there + // directly, bypassing DWARF compatibility functions. - let eh_action = match find_eh_action(context) { - Ok(action) => action, - Err(_) => return uw::_URC_FAILURE, - }; - if search_phase { - match eh_action { - EHAction::None | EHAction::Cleanup(_) => { - return continue_unwind(exception_object, context); + let eh_action = match find_eh_action(context) { + Ok(action) => action, + Err(_) => return uw::_URC_FAILURE, + }; + if search_phase { + match eh_action { + EHAction::None | EHAction::Cleanup(_) => { + return continue_unwind(exception_object, context); + } + EHAction::Catch(_) | EHAction::Filter(_) => { + // EHABI requires the personality routine to update the + // SP value in the barrier cache of the exception object. + (*exception_object).private[5] = + uw::_Unwind_GetGR(context, uw::UNWIND_SP_REG); + return uw::_URC_HANDLER_FOUND; + } + EHAction::Terminate => return uw::_URC_FAILURE, } - EHAction::Catch(_) | EHAction::Filter(_) => { - // EHABI requires the personality routine to update the - // SP value in the barrier cache of the exception object. - (*exception_object).private[5] = - uw::_Unwind_GetGR(context, uw::UNWIND_SP_REG); - return uw::_URC_HANDLER_FOUND; - } - EHAction::Terminate => return uw::_URC_FAILURE, - } - } else { - match eh_action { - EHAction::None => return continue_unwind(exception_object, context), - EHAction::Filter(_) if state & uw::_US_FORCE_UNWIND as c_int != 0 => return continue_unwind(exception_object, context), - EHAction::Cleanup(lpad) | EHAction::Catch(lpad) | EHAction::Filter(lpad) => { - uw::_Unwind_SetGR( - context, - UNWIND_DATA_REG.0, - exception_object as uw::_Unwind_Ptr, - ); - uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, core::ptr::null()); - uw::_Unwind_SetIP(context, lpad); - return uw::_URC_INSTALL_CONTEXT; + } else { + match eh_action { + EHAction::None => return continue_unwind(exception_object, context), + EHAction::Filter(_) if state & uw::_US_FORCE_UNWIND as c_int != 0 => return continue_unwind(exception_object, context), + EHAction::Cleanup(lpad) | EHAction::Catch(lpad) | EHAction::Filter(lpad) => { + uw::_Unwind_SetGR( + context, + UNWIND_DATA_REG.0, + exception_object as uw::_Unwind_Ptr, + ); + uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, core::ptr::null()); + uw::_Unwind_SetIP(context, lpad); + return uw::_URC_INSTALL_CONTEXT; + } + EHAction::Terminate => return uw::_URC_FAILURE, } - EHAction::Terminate => return uw::_URC_FAILURE, } - } - // On ARM EHABI the personality routine is responsible for actually - // unwinding a single stack frame before returning (ARM EHABI Sec. 6.1). - unsafe fn continue_unwind( - exception_object: *mut uw::_Unwind_Exception, - context: *mut uw::_Unwind_Context, - ) -> uw::_Unwind_Reason_Code { - if __gnu_unwind_frame(exception_object, context) == uw::_URC_NO_REASON { - uw::_URC_CONTINUE_UNWIND - } else { - uw::_URC_FAILURE - } - } - // defined in libgcc - extern "C" { - fn __gnu_unwind_frame( + // On ARM EHABI the personality routine is responsible for actually + // unwinding a single stack frame before returning (ARM EHABI Sec. 6.1). + unsafe fn continue_unwind( exception_object: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context, - ) -> uw::_Unwind_Reason_Code; + ) -> uw::_Unwind_Reason_Code { + unsafe { + if __gnu_unwind_frame(exception_object, context) == uw::_URC_NO_REASON { + uw::_URC_CONTINUE_UNWIND + } else { + uw::_URC_FAILURE + } + } + } + // defined in libgcc + extern "C" { + fn __gnu_unwind_frame( + exception_object: *mut uw::_Unwind_Exception, + context: *mut uw::_Unwind_Context, + ) -> uw::_Unwind_Reason_Code; + } } } } else { @@ -200,35 +209,37 @@ cfg_if::cfg_if! { exception_object: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context, ) -> uw::_Unwind_Reason_Code { - if version != 1 { - return uw::_URC_FATAL_PHASE1_ERROR; - } - let eh_action = match find_eh_action(context) { - Ok(action) => action, - Err(_) => return uw::_URC_FATAL_PHASE1_ERROR, - }; - if actions as i32 & uw::_UA_SEARCH_PHASE as i32 != 0 { - match eh_action { - EHAction::None | EHAction::Cleanup(_) => uw::_URC_CONTINUE_UNWIND, - EHAction::Catch(_) | EHAction::Filter(_) => uw::_URC_HANDLER_FOUND, - EHAction::Terminate => uw::_URC_FATAL_PHASE1_ERROR, + unsafe { + if version != 1 { + return uw::_URC_FATAL_PHASE1_ERROR; } - } else { - match eh_action { - EHAction::None => uw::_URC_CONTINUE_UNWIND, - // Forced unwinding hits a terminate action. - EHAction::Filter(_) if actions as i32 & uw::_UA_FORCE_UNWIND as i32 != 0 => uw::_URC_CONTINUE_UNWIND, - EHAction::Cleanup(lpad) | EHAction::Catch(lpad) | EHAction::Filter(lpad) => { - uw::_Unwind_SetGR( - context, - UNWIND_DATA_REG.0, - exception_object.cast(), - ); - uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, core::ptr::null()); - uw::_Unwind_SetIP(context, lpad); - uw::_URC_INSTALL_CONTEXT + let eh_action = match find_eh_action(context) { + Ok(action) => action, + Err(_) => return uw::_URC_FATAL_PHASE1_ERROR, + }; + if actions as i32 & uw::_UA_SEARCH_PHASE as i32 != 0 { + match eh_action { + EHAction::None | EHAction::Cleanup(_) => uw::_URC_CONTINUE_UNWIND, + EHAction::Catch(_) | EHAction::Filter(_) => uw::_URC_HANDLER_FOUND, + EHAction::Terminate => uw::_URC_FATAL_PHASE1_ERROR, + } + } else { + match eh_action { + EHAction::None => uw::_URC_CONTINUE_UNWIND, + // Forced unwinding hits a terminate action. + EHAction::Filter(_) if actions as i32 & uw::_UA_FORCE_UNWIND as i32 != 0 => uw::_URC_CONTINUE_UNWIND, + EHAction::Cleanup(lpad) | EHAction::Catch(lpad) | EHAction::Filter(lpad) => { + uw::_Unwind_SetGR( + context, + UNWIND_DATA_REG.0, + exception_object.cast(), + ); + uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, core::ptr::null()); + uw::_Unwind_SetIP(context, lpad); + uw::_URC_INSTALL_CONTEXT + } + EHAction::Terminate => uw::_URC_FATAL_PHASE2_ERROR, } - EHAction::Terminate => uw::_URC_FATAL_PHASE2_ERROR, } } } @@ -245,13 +256,15 @@ cfg_if::cfg_if! { contextRecord: *mut uw::CONTEXT, dispatcherContext: *mut uw::DISPATCHER_CONTEXT, ) -> uw::EXCEPTION_DISPOSITION { - uw::_GCC_specific_handler( - exceptionRecord, - establisherFrame, - contextRecord, - dispatcherContext, - rust_eh_personality_impl, - ) + unsafe { + uw::_GCC_specific_handler( + exceptionRecord, + establisherFrame, + contextRecord, + dispatcherContext, + rust_eh_personality_impl, + ) + } } } else { // The personality routine for most of our targets. @@ -263,13 +276,15 @@ cfg_if::cfg_if! { exception_object: *mut uw::_Unwind_Exception, context: *mut uw::_Unwind_Context, ) -> uw::_Unwind_Reason_Code { - rust_eh_personality_impl( - version, - actions, - exception_class, - exception_object, - context, - ) + unsafe { + rust_eh_personality_impl( + version, + actions, + exception_class, + exception_object, + context, + ) + } } } } @@ -277,18 +292,20 @@ cfg_if::cfg_if! { } unsafe fn find_eh_action(context: *mut uw::_Unwind_Context) -> Result { - let lsda = uw::_Unwind_GetLanguageSpecificData(context) as *const u8; - let mut ip_before_instr: c_int = 0; - let ip = uw::_Unwind_GetIPInfo(context, &mut ip_before_instr); - let eh_context = EHContext { - // The return address points 1 byte past the call instruction, - // which could be in the next IP range in LSDA range table. - // - // `ip = -1` has special meaning, so use wrapping sub to allow for that - ip: if ip_before_instr != 0 { ip } else { ip.wrapping_sub(1) }, - func_start: uw::_Unwind_GetRegionStart(context), - get_text_start: &|| uw::_Unwind_GetTextRelBase(context), - get_data_start: &|| uw::_Unwind_GetDataRelBase(context), - }; - eh::find_eh_action(lsda, &eh_context) + unsafe { + let lsda = uw::_Unwind_GetLanguageSpecificData(context) as *const u8; + let mut ip_before_instr: c_int = 0; + let ip = uw::_Unwind_GetIPInfo(context, &mut ip_before_instr); + let eh_context = EHContext { + // The return address points 1 byte past the call instruction, + // which could be in the next IP range in LSDA range table. + // + // `ip = -1` has special meaning, so use wrapping sub to allow for that + ip: if ip_before_instr != 0 { ip } else { ip.wrapping_sub(1) }, + func_start: uw::_Unwind_GetRegionStart(context), + get_text_start: &|| uw::_Unwind_GetTextRelBase(context), + get_data_start: &|| uw::_Unwind_GetDataRelBase(context), + }; + eh::find_eh_action(lsda, &eh_context) + } }