diff options
Diffstat (limited to 'library/panic_unwind/src/gcc.rs')
| -rw-r--r-- | library/panic_unwind/src/gcc.rs | 262 |
1 files changed, 0 insertions, 262 deletions
diff --git a/library/panic_unwind/src/gcc.rs b/library/panic_unwind/src/gcc.rs index a59659231..261404e87 100644 --- a/library/panic_unwind/src/gcc.rs +++ b/library/panic_unwind/src/gcc.rs @@ -39,8 +39,6 @@ use alloc::boxed::Box; use core::any::Any; -use crate::dwarf::eh::{self, EHAction, EHContext}; -use libc::{c_int, uintptr_t}; use unwind as uw; #[repr(C)] @@ -89,263 +87,3 @@ fn rust_exception_class() -> uw::_Unwind_Exception_Class { // M O Z \0 R U S T -- vendor, language 0x4d4f5a_00_52555354 } - -// Register ids were lifted from LLVM's TargetLowering::getExceptionPointerRegister() -// and TargetLowering::getExceptionSelectorRegister() for each architecture, -// then mapped to DWARF register numbers via register definition tables -// (typically <arch>RegisterInfo.td, search for "DwarfRegNum"). -// See also https://llvm.org/docs/WritingAnLLVMBackend.html#defining-a-register. - -#[cfg(target_arch = "x86")] -const UNWIND_DATA_REG: (i32, i32) = (0, 2); // EAX, EDX - -#[cfg(target_arch = "x86_64")] -const UNWIND_DATA_REG: (i32, i32) = (0, 1); // RAX, RDX - -#[cfg(any(target_arch = "arm", target_arch = "aarch64"))] -const UNWIND_DATA_REG: (i32, i32) = (0, 1); // R0, R1 / X0, X1 - -#[cfg(target_arch = "m68k")] -const UNWIND_DATA_REG: (i32, i32) = (0, 1); // D0, D1 - -#[cfg(any(target_arch = "mips", target_arch = "mips64"))] -const UNWIND_DATA_REG: (i32, i32) = (4, 5); // A0, A1 - -#[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))] -const UNWIND_DATA_REG: (i32, i32) = (3, 4); // R3, R4 / X3, X4 - -#[cfg(target_arch = "s390x")] -const UNWIND_DATA_REG: (i32, i32) = (6, 7); // R6, R7 - -#[cfg(any(target_arch = "sparc", target_arch = "sparc64"))] -const UNWIND_DATA_REG: (i32, i32) = (24, 25); // I0, I1 - -#[cfg(target_arch = "hexagon")] -const UNWIND_DATA_REG: (i32, i32) = (0, 1); // R0, R1 - -#[cfg(any(target_arch = "riscv64", target_arch = "riscv32"))] -const UNWIND_DATA_REG: (i32, i32) = (10, 11); // x10, x11 - -// The following code is based on GCC's C and C++ personality routines. For reference, see: -// https://github.com/gcc-mirror/gcc/blob/master/libstdc++-v3/libsupc++/eh_personality.cc -// https://github.com/gcc-mirror/gcc/blob/trunk/libgcc/unwind-c.c - -cfg_if::cfg_if! { - if #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(target_os = "watchos"), not(target_os = "netbsd")))] { - // ARM EHABI personality routine. - // https://infocenter.arm.com/help/topic/com.arm.doc.ihi0038b/IHI0038B_ehabi.pdf - // - // iOS uses the default routine instead since it uses SjLj unwinding. - #[lang = "eh_personality"] - unsafe extern "C" fn rust_eh_personality(state: uw::_Unwind_State, - 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 { - 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; - }; - - // 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), - EHAction::Catch(_) => { - // 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::Cleanup(lpad) | - EHAction::Catch(lpad) => { - uw::_Unwind_SetGR(context, UNWIND_DATA_REG.0, - exception_object as uintptr_t); - uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, 0); - uw::_Unwind_SetIP(context, lpad); - return uw::_URC_INSTALL_CONTEXT; - } - 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(exception_object: *mut uw::_Unwind_Exception, - context: *mut uw::_Unwind_Context) - -> uw::_Unwind_Reason_Code; - } - } - } else { - // Default personality routine, which is used directly on most targets - // and indirectly on Windows x86_64 via SEH. - unsafe extern "C" fn rust_eh_personality_impl(version: c_int, - actions: uw::_Unwind_Action, - _exception_class: uw::_Unwind_Exception_Class, - 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(_) => uw::_URC_HANDLER_FOUND, - EHAction::Terminate => uw::_URC_FATAL_PHASE1_ERROR, - } - } else { - match eh_action { - EHAction::None => uw::_URC_CONTINUE_UNWIND, - EHAction::Cleanup(lpad) | - EHAction::Catch(lpad) => { - uw::_Unwind_SetGR(context, UNWIND_DATA_REG.0, - exception_object as uintptr_t); - uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, 0); - uw::_Unwind_SetIP(context, lpad); - uw::_URC_INSTALL_CONTEXT - } - EHAction::Terminate => uw::_URC_FATAL_PHASE2_ERROR, - } - } - } - - cfg_if::cfg_if! { - if #[cfg(all(windows, target_arch = "x86_64", target_env = "gnu"))] { - // On x86_64 MinGW targets, the unwinding mechanism is SEH however the unwind - // handler data (aka LSDA) uses GCC-compatible encoding. - #[lang = "eh_personality"] - #[allow(nonstandard_style)] - unsafe extern "C" fn rust_eh_personality(exceptionRecord: *mut uw::EXCEPTION_RECORD, - establisherFrame: uw::LPVOID, - contextRecord: *mut uw::CONTEXT, - dispatcherContext: *mut uw::DISPATCHER_CONTEXT) - -> uw::EXCEPTION_DISPOSITION { - uw::_GCC_specific_handler(exceptionRecord, - establisherFrame, - contextRecord, - dispatcherContext, - rust_eh_personality_impl) - } - } else { - // The personality routine for most of our targets. - #[lang = "eh_personality"] - unsafe extern "C" fn rust_eh_personality(version: c_int, - actions: uw::_Unwind_Action, - exception_class: uw::_Unwind_Exception_Class, - 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 fn find_eh_action(context: *mut uw::_Unwind_Context) -> Result<EHAction, ()> { - 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) -} - -// Frame unwind info registration -// -// Each module's image contains a frame unwind info section (usually -// ".eh_frame"). When a module is loaded/unloaded into the process, the -// unwinder must be informed about the location of this section in memory. The -// methods of achieving that vary by the platform. On some (e.g., Linux), the -// unwinder can discover unwind info sections on its own (by dynamically -// enumerating currently loaded modules via the dl_iterate_phdr() API and -// finding their ".eh_frame" sections); Others, like Windows, require modules -// to actively register their unwind info sections via unwinder API. -// -// This module defines two symbols which are referenced and called from -// rsbegin.rs to register our information with the GCC runtime. 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 any GCC runtime. -#[cfg(all(target_os = "windows", target_arch = "x86", target_env = "gnu"))] -pub mod eh_frame_registry { - extern "C" { - fn __register_frame_info(eh_frame_begin: *const u8, object: *mut u8); - fn __deregister_frame_info(eh_frame_begin: *const u8, object: *mut u8); - } - - #[rustc_std_internal_symbol] - pub unsafe extern "C" fn rust_eh_register_frames(eh_frame_begin: *const u8, object: *mut u8) { - __register_frame_info(eh_frame_begin, object); - } - - #[rustc_std_internal_symbol] - pub unsafe extern "C" fn rust_eh_unregister_frames(eh_frame_begin: *const u8, object: *mut u8) { - __deregister_frame_info(eh_frame_begin, object); - } -} |