| /* Exception handling and frame unwind runtime interface routines. -*- C -*- |
| Copyright (C) 2001-2023 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3, or (at your option) |
| any later version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public |
| License for more details. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* This is derived from the C++ ABI for IA-64. Where we diverge |
| for cross-architecture compatibility are noted with "@@@". |
| This file is included from unwind-dw2.c, unwind-sjlj.c or |
| unwind-ia64.c. */ |
| |
| /* Subroutine of _Unwind_RaiseException also invoked from _Unwind_Resume. |
| |
| Unwind the stack calling the personality routine to find both the |
| exception handler and intermediary cleanup code. We'll only locate |
| the first such frame here. Cleanup code will call back into |
| _Unwind_Resume and we'll continue Phase 2 there. */ |
| |
| static _Unwind_Reason_Code |
| _Unwind_RaiseException_Phase2(struct _Unwind_Exception *exc, |
| struct _Unwind_Context *context, |
| unsigned long *frames_p) |
| { |
| _Unwind_Reason_Code code; |
| unsigned long frames = 1; |
| |
| while (1) |
| { |
| _Unwind_FrameState fs; |
| int match_handler; |
| |
| code = uw_frame_state_for (context, &fs); |
| |
| /* Identify when we've reached the designated handler context. */ |
| match_handler = (uw_identify_context (context) == exc->private_2 |
| ? _UA_HANDLER_FRAME : 0); |
| |
| if (code != _URC_NO_REASON) |
| /* Some error encountered. Usually the unwinder doesn't |
| diagnose these and merely crashes. */ |
| return _URC_FATAL_PHASE2_ERROR; |
| |
| /* Unwind successful. Run the personality routine, if any. */ |
| if (fs.personality) |
| { |
| code = (*fs.personality) (1, _UA_CLEANUP_PHASE | match_handler, |
| exc->exception_class, exc, context); |
| if (code == _URC_INSTALL_CONTEXT) |
| break; |
| if (code != _URC_CONTINUE_UNWIND) |
| return _URC_FATAL_PHASE2_ERROR; |
| } |
| |
| /* Don't let us unwind past the handler context. */ |
| gcc_assert (!match_handler); |
| |
| uw_update_context (context, &fs); |
| _Unwind_Frames_Increment (exc, context, frames); |
| } |
| |
| *frames_p = frames; |
| return code; |
| } |
| |
| /* Raise an exception, passing along the given exception object. */ |
| |
| _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
| _Unwind_RaiseException(struct _Unwind_Exception *exc) |
| { |
| struct _Unwind_Context this_context, cur_context; |
| _Unwind_Reason_Code code; |
| unsigned long frames; |
| |
| /* Set up this_context to describe the current stack frame. */ |
| uw_init_context (&this_context); |
| cur_context = this_context; |
| |
| /* Phase 1: Search. Unwind the stack, calling the personality routine |
| with the _UA_SEARCH_PHASE flag set. Do not modify the stack yet. */ |
| while (1) |
| { |
| _Unwind_FrameState fs; |
| |
| /* Set up fs to describe the FDE for the caller of cur_context. The |
| first time through the loop, that means __cxa_throw. */ |
| code = uw_frame_state_for (&cur_context, &fs); |
| |
| if (code == _URC_END_OF_STACK) |
| /* Hit end of stack with no handler found. */ |
| return _URC_END_OF_STACK; |
| |
| if (code != _URC_NO_REASON) |
| /* Some error encountered. Usually the unwinder doesn't |
| diagnose these and merely crashes. */ |
| return _URC_FATAL_PHASE1_ERROR; |
| |
| /* Unwind successful. Run the personality routine, if any. */ |
| if (fs.personality) |
| { |
| code = (*fs.personality) (1, _UA_SEARCH_PHASE, exc->exception_class, |
| exc, &cur_context); |
| if (code == _URC_HANDLER_FOUND) |
| break; |
| else if (code != _URC_CONTINUE_UNWIND) |
| return _URC_FATAL_PHASE1_ERROR; |
| } |
| |
| /* Update cur_context to describe the same frame as fs. */ |
| uw_update_context (&cur_context, &fs); |
| } |
| |
| /* Indicate to _Unwind_Resume and associated subroutines that this |
| is not a forced unwind. Further, note where we found a handler. */ |
| exc->private_1 = 0; |
| exc->private_2 = uw_identify_context (&cur_context); |
| |
| cur_context = this_context; |
| code = _Unwind_RaiseException_Phase2 (exc, &cur_context, &frames); |
| if (code != _URC_INSTALL_CONTEXT) |
| return code; |
| |
| uw_install_context (&this_context, &cur_context, frames); |
| } |
| |
| |
| /* Subroutine of _Unwind_ForcedUnwind also invoked from _Unwind_Resume. */ |
| |
| static _Unwind_Reason_Code |
| _Unwind_ForcedUnwind_Phase2 (struct _Unwind_Exception *exc, |
| struct _Unwind_Context *context, |
| unsigned long *frames_p) |
| { |
| _Unwind_Stop_Fn stop = (_Unwind_Stop_Fn) (_Unwind_Ptr) exc->private_1; |
| void *stop_argument = (void *) (_Unwind_Ptr) exc->private_2; |
| _Unwind_Reason_Code code, stop_code; |
| unsigned long frames = 1; |
| |
| while (1) |
| { |
| _Unwind_FrameState fs; |
| int action; |
| |
| /* Set up fs to describe the FDE for the caller of cur_context. */ |
| code = uw_frame_state_for (context, &fs); |
| if (code != _URC_NO_REASON && code != _URC_END_OF_STACK |
| && code != _URC_NORMAL_STOP) |
| return _URC_FATAL_PHASE2_ERROR; |
| |
| /* Unwind successful. */ |
| action = _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE; |
| if (code == _URC_END_OF_STACK || code == _URC_NORMAL_STOP) |
| action |= _UA_END_OF_STACK; |
| stop_code = (*stop) (1, action, exc->exception_class, exc, |
| context, stop_argument); |
| if (stop_code != _URC_NO_REASON) |
| return _URC_FATAL_PHASE2_ERROR; |
| |
| /* Stop didn't want to do anything. Invoke the personality |
| handler, if applicable, to run cleanups. */ |
| if (code == _URC_END_OF_STACK) |
| break; |
| |
| if (fs.personality) |
| { |
| code = (*fs.personality) (1, _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE, |
| exc->exception_class, exc, context); |
| if (code == _URC_INSTALL_CONTEXT) |
| break; |
| if (code != _URC_CONTINUE_UNWIND) |
| return _URC_FATAL_PHASE2_ERROR; |
| } |
| |
| /* Update cur_context to describe the same frame as fs, and discard |
| the previous context if necessary. */ |
| uw_advance_context (context, &fs); |
| _Unwind_Frames_Increment (exc, context, frames); |
| } |
| |
| *frames_p = frames; |
| return code; |
| } |
| |
| |
| /* Raise an exception for forced unwinding. */ |
| |
| _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
| _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, |
| _Unwind_Stop_Fn stop, void * stop_argument) |
| { |
| struct _Unwind_Context this_context, cur_context; |
| _Unwind_Reason_Code code; |
| unsigned long frames; |
| |
| uw_init_context (&this_context); |
| cur_context = this_context; |
| |
| exc->private_1 = (_Unwind_Ptr) stop; |
| exc->private_2 = (_Unwind_Ptr) stop_argument; |
| |
| code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context, &frames); |
| if (code != _URC_INSTALL_CONTEXT) |
| return code; |
| |
| uw_install_context (&this_context, &cur_context, frames); |
| } |
| |
| |
| /* Resume propagation of an existing exception. This is used after |
| e.g. executing cleanup code, and not to implement rethrowing. */ |
| |
| void LIBGCC2_UNWIND_ATTRIBUTE |
| _Unwind_Resume (struct _Unwind_Exception *exc) |
| { |
| struct _Unwind_Context this_context, cur_context; |
| _Unwind_Reason_Code code; |
| unsigned long frames; |
| |
| uw_init_context (&this_context); |
| cur_context = this_context; |
| |
| /* Choose between continuing to process _Unwind_RaiseException |
| or _Unwind_ForcedUnwind. */ |
| if (exc->private_1 == 0) |
| code = _Unwind_RaiseException_Phase2 (exc, &cur_context, &frames); |
| else |
| code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context, &frames); |
| |
| gcc_assert (code == _URC_INSTALL_CONTEXT); |
| |
| uw_install_context (&this_context, &cur_context, frames); |
| } |
| |
| |
| /* Resume propagation of an FORCE_UNWIND exception, or to rethrow |
| a normal exception that was handled. */ |
| |
| _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
| _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *exc) |
| { |
| struct _Unwind_Context this_context, cur_context; |
| _Unwind_Reason_Code code; |
| unsigned long frames; |
| |
| /* Choose between continuing to process _Unwind_RaiseException |
| or _Unwind_ForcedUnwind. */ |
| if (exc->private_1 == 0) |
| return _Unwind_RaiseException (exc); |
| |
| uw_init_context (&this_context); |
| cur_context = this_context; |
| |
| code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context, &frames); |
| |
| gcc_assert (code == _URC_INSTALL_CONTEXT); |
| |
| uw_install_context (&this_context, &cur_context, frames); |
| } |
| |
| |
| /* A convenience function that calls the exception_cleanup field. */ |
| |
| void |
| _Unwind_DeleteException (struct _Unwind_Exception *exc) |
| { |
| if (exc->exception_cleanup) |
| (*exc->exception_cleanup) (_URC_FOREIGN_EXCEPTION_CAUGHT, exc); |
| } |
| |
| |
| /* Perform stack backtrace through unwind data. */ |
| |
| _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
| _Unwind_Backtrace(_Unwind_Trace_Fn trace, void * trace_argument) |
| { |
| struct _Unwind_Context context; |
| _Unwind_Reason_Code code; |
| |
| uw_init_context (&context); |
| |
| while (1) |
| { |
| _Unwind_FrameState fs; |
| |
| /* Set up fs to describe the FDE for the caller of context. */ |
| code = uw_frame_state_for (&context, &fs); |
| if (code != _URC_NO_REASON && code != _URC_END_OF_STACK |
| && code != _URC_NORMAL_STOP) |
| return _URC_FATAL_PHASE1_ERROR; |
| |
| /* Call trace function. */ |
| if ((*trace) (&context, trace_argument) != _URC_NO_REASON) |
| return _URC_FATAL_PHASE1_ERROR; |
| |
| #ifdef MD_BACKCHAIN_FALLBACK |
| /* Do a backchain if there is no DWARF data. */ |
| if (code == _URC_NORMAL_STOP) |
| { |
| MD_BACKCHAIN_FALLBACK(&context, trace_argument); |
| break; |
| } |
| #endif |
| |
| /* We're done at end of stack. */ |
| if (code == _URC_END_OF_STACK) |
| break; |
| |
| /* Update context to describe the same frame as fs. */ |
| uw_update_context (&context, &fs); |
| } |
| |
| return code; |
| } |