| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- A D A . E X C E P T I O N S . E X C E P T I O N _ P R O P A G A T I O N -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2013, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| -- -- |
| -- As a special exception 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/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This is the version using the GCC EH mechanism |
| |
| with Ada.Unchecked_Conversion; |
| with Ada.Unchecked_Deallocation; |
| |
| with System.Storage_Elements; use System.Storage_Elements; |
| with System.Exceptions.Machine; use System.Exceptions.Machine; |
| |
| separate (Ada.Exceptions) |
| package body Exception_Propagation is |
| |
| use Exception_Traces; |
| |
| Foreign_Exception : aliased System.Standard_Library.Exception_Data; |
| pragma Import (Ada, Foreign_Exception, |
| "system__exceptions__foreign_exception"); |
| -- Id for foreign exceptions |
| |
| -------------------------------------------------------------- |
| -- GNAT Specific Entities To Deal With The GCC EH Circuitry -- |
| -------------------------------------------------------------- |
| |
| procedure GNAT_GCC_Exception_Cleanup |
| (Reason : Unwind_Reason_Code; |
| Excep : not null GNAT_GCC_Exception_Access); |
| pragma Convention (C, GNAT_GCC_Exception_Cleanup); |
| -- Procedure called when a GNAT GCC exception is free. |
| |
| procedure Propagate_GCC_Exception |
| (GCC_Exception : not null GCC_Exception_Access); |
| pragma No_Return (Propagate_GCC_Exception); |
| -- Propagate a GCC exception |
| |
| procedure Reraise_GCC_Exception |
| (GCC_Exception : not null GCC_Exception_Access); |
| pragma No_Return (Reraise_GCC_Exception); |
| pragma Export (C, Reraise_GCC_Exception, "__gnat_reraise_zcx"); |
| -- Called to implement raise without exception, ie reraise. Called |
| -- directly from gigi. |
| |
| function Setup_Current_Excep |
| (GCC_Exception : not null GCC_Exception_Access) return EOA; |
| pragma Export (C, Setup_Current_Excep, "__gnat_setup_current_excep"); |
| -- Write Get_Current_Excep.all from GCC_Exception. Called by the |
| -- personality routine. |
| |
| procedure Unhandled_Except_Handler |
| (GCC_Exception : not null GCC_Exception_Access); |
| pragma No_Return (Unhandled_Except_Handler); |
| pragma Export (C, Unhandled_Except_Handler, |
| "__gnat_unhandled_except_handler"); |
| -- Called for handle unhandled exceptions, ie the last chance handler |
| -- on platforms (such as SEH) that never returns after throwing an |
| -- exception. Called directly by gigi. |
| |
| function CleanupUnwind_Handler |
| (UW_Version : Integer; |
| UW_Phases : Unwind_Action; |
| UW_Eclass : Exception_Class; |
| UW_Exception : not null GCC_Exception_Access; |
| UW_Context : System.Address; |
| UW_Argument : System.Address) return Unwind_Reason_Code; |
| pragma Import (C, CleanupUnwind_Handler, |
| "__gnat_cleanupunwind_handler"); |
| -- Hook called at each step of the forced unwinding we perform to trigger |
| -- cleanups found during the propagation of an unhandled exception. |
| |
| -- GCC runtime functions used. These are C non-void functions, actually, |
| -- but we ignore the return values. See raise.c as to why we are using |
| -- __gnat stubs for these. |
| |
| procedure Unwind_RaiseException |
| (UW_Exception : not null GCC_Exception_Access); |
| pragma Import (C, Unwind_RaiseException, "__gnat_Unwind_RaiseException"); |
| |
| procedure Unwind_ForcedUnwind |
| (UW_Exception : not null GCC_Exception_Access; |
| UW_Handler : System.Address; |
| UW_Argument : System.Address); |
| pragma Import (C, Unwind_ForcedUnwind, "__gnat_Unwind_ForcedUnwind"); |
| |
| procedure Set_Exception_Parameter |
| (Excep : EOA; |
| GCC_Exception : not null GCC_Exception_Access); |
| pragma Export |
| (C, Set_Exception_Parameter, "__gnat_set_exception_parameter"); |
| -- Called inserted by gigi to initialize the exception parameter |
| |
| procedure Set_Foreign_Occurrence (Excep : EOA; Mo : System.Address); |
| -- Utility routine to initialize occurrence Excep from a foreign exception |
| -- whose machine occurrence is Mo. The message is empty, the backtrace |
| -- is empty too and the exception identity is Foreign_Exception. |
| |
| -- Hooks called when entering/leaving an exception handler for a given |
| -- occurrence, aimed at handling the stack of active occurrences. The |
| -- calls are generated by gigi in tree_transform/N_Exception_Handler. |
| |
| procedure Begin_Handler (GCC_Exception : not null GCC_Exception_Access); |
| pragma Export (C, Begin_Handler, "__gnat_begin_handler"); |
| |
| procedure End_Handler (GCC_Exception : GCC_Exception_Access); |
| pragma Export (C, End_Handler, "__gnat_end_handler"); |
| |
| -------------------------------------------------------------------- |
| -- Accessors to Basic Components of a GNAT Exception Data Pointer -- |
| -------------------------------------------------------------------- |
| |
| -- As of today, these are only used by the C implementation of the GCC |
| -- propagation personality routine to avoid having to rely on a C |
| -- counterpart of the whole exception_data structure, which is both |
| -- painful and error prone. These subprograms could be moved to a more |
| -- widely visible location if need be. |
| |
| function Is_Handled_By_Others (E : Exception_Data_Ptr) return Boolean; |
| pragma Export (C, Is_Handled_By_Others, "__gnat_is_handled_by_others"); |
| pragma Warnings (Off, Is_Handled_By_Others); |
| |
| function Language_For (E : Exception_Data_Ptr) return Character; |
| pragma Export (C, Language_For, "__gnat_language_for"); |
| |
| function Foreign_Data_For (E : Exception_Data_Ptr) return Address; |
| pragma Export (C, Foreign_Data_For, "__gnat_foreign_data_for"); |
| |
| function EID_For (GNAT_Exception : not null GNAT_GCC_Exception_Access) |
| return Exception_Id; |
| pragma Export (C, EID_For, "__gnat_eid_for"); |
| |
| --------------------------------------------------------------------------- |
| -- Objects to materialize "others" and "all others" in the GCC EH tables -- |
| --------------------------------------------------------------------------- |
| |
| -- Currently, these only have their address taken and compared so there is |
| -- no real point having whole exception data blocks allocated. Note that |
| -- there are corresponding declarations in gigi (trans.c) which must be |
| -- kept properly synchronized. |
| |
| Others_Value : constant Character := 'O'; |
| pragma Export (C, Others_Value, "__gnat_others_value"); |
| |
| All_Others_Value : constant Character := 'A'; |
| pragma Export (C, All_Others_Value, "__gnat_all_others_value"); |
| |
| Unhandled_Others_Value : constant Character := 'U'; |
| pragma Export (C, Unhandled_Others_Value, "__gnat_unhandled_others_value"); |
| -- Special choice (emitted by gigi) to catch and notify unhandled |
| -- exceptions on targets which always handle exceptions (such as SEH). |
| -- The handler will simply call Unhandled_Except_Handler. |
| |
| ------------------------- |
| -- Allocate_Occurrence -- |
| ------------------------- |
| |
| function Allocate_Occurrence return EOA is |
| Res : GNAT_GCC_Exception_Access; |
| |
| begin |
| Res := New_Occurrence; |
| Res.Header.Cleanup := GNAT_GCC_Exception_Cleanup'Address; |
| Res.Occurrence.Machine_Occurrence := Res.all'Address; |
| |
| return Res.Occurrence'Access; |
| end Allocate_Occurrence; |
| |
| -------------------------------- |
| -- GNAT_GCC_Exception_Cleanup -- |
| -------------------------------- |
| |
| procedure GNAT_GCC_Exception_Cleanup |
| (Reason : Unwind_Reason_Code; |
| Excep : not null GNAT_GCC_Exception_Access) |
| is |
| pragma Unreferenced (Reason); |
| |
| procedure Free is new Unchecked_Deallocation |
| (GNAT_GCC_Exception, GNAT_GCC_Exception_Access); |
| |
| Copy : GNAT_GCC_Exception_Access := Excep; |
| |
| begin |
| -- Simply free the memory |
| |
| Free (Copy); |
| end GNAT_GCC_Exception_Cleanup; |
| |
| ---------------------------- |
| -- Set_Foreign_Occurrence -- |
| ---------------------------- |
| |
| procedure Set_Foreign_Occurrence (Excep : EOA; Mo : System.Address) is |
| begin |
| Excep.all := ( |
| Id => Foreign_Exception'Access, |
| Machine_Occurrence => Mo, |
| Msg => <>, |
| Msg_Length => 0, |
| Exception_Raised => True, |
| Pid => Local_Partition_ID, |
| Num_Tracebacks => 0, |
| Tracebacks => <>); |
| end Set_Foreign_Occurrence; |
| |
| ------------------------- |
| -- Setup_Current_Excep -- |
| ------------------------- |
| |
| function Setup_Current_Excep |
| (GCC_Exception : not null GCC_Exception_Access) return EOA |
| is |
| Excep : constant EOA := Get_Current_Excep.all; |
| |
| begin |
| -- Setup the exception occurrence |
| |
| if GCC_Exception.Class = GNAT_Exception_Class then |
| |
| -- From the GCC exception |
| |
| declare |
| GNAT_Occurrence : constant GNAT_GCC_Exception_Access := |
| To_GNAT_GCC_Exception (GCC_Exception); |
| begin |
| Excep.all := GNAT_Occurrence.Occurrence; |
| return GNAT_Occurrence.Occurrence'Access; |
| end; |
| |
| else |
| -- A default one |
| |
| Set_Foreign_Occurrence (Excep, GCC_Exception.all'Address); |
| |
| return Excep; |
| end if; |
| end Setup_Current_Excep; |
| |
| ------------------- |
| -- Begin_Handler -- |
| ------------------- |
| |
| procedure Begin_Handler (GCC_Exception : not null GCC_Exception_Access) is |
| pragma Unreferenced (GCC_Exception); |
| begin |
| null; |
| end Begin_Handler; |
| |
| ----------------- |
| -- End_Handler -- |
| ----------------- |
| |
| procedure End_Handler (GCC_Exception : GCC_Exception_Access) is |
| begin |
| if GCC_Exception /= null then |
| |
| -- The exception might have been reraised, in this case the cleanup |
| -- mustn't be called. |
| |
| Unwind_DeleteException (GCC_Exception); |
| end if; |
| end End_Handler; |
| |
| ----------------------------- |
| -- Reraise_GCC_Exception -- |
| ----------------------------- |
| |
| procedure Reraise_GCC_Exception |
| (GCC_Exception : not null GCC_Exception_Access) |
| is |
| begin |
| -- Simply propagate it |
| |
| Propagate_GCC_Exception (GCC_Exception); |
| end Reraise_GCC_Exception; |
| |
| ----------------------------- |
| -- Propagate_GCC_Exception -- |
| ----------------------------- |
| |
| -- Call Unwind_RaiseException to actually throw, taking care of handling |
| -- the two phase scheme it implements. |
| |
| procedure Propagate_GCC_Exception |
| (GCC_Exception : not null GCC_Exception_Access) |
| is |
| Excep : EOA; |
| |
| begin |
| -- Perform a standard raise first. If a regular handler is found, it |
| -- will be entered after all the intermediate cleanups have run. If |
| -- there is no regular handler, it will return. |
| |
| Unwind_RaiseException (GCC_Exception); |
| |
| -- If we get here we know the exception is not handled, as otherwise |
| -- Unwind_RaiseException arranges for the handler to be entered. Take |
| -- the necessary steps to enable the debugger to gain control while the |
| -- stack is still intact. |
| |
| Excep := Setup_Current_Excep (GCC_Exception); |
| Notify_Unhandled_Exception (Excep); |
| |
| -- Now, un a forced unwind to trigger cleanups. Control should not |
| -- resume there, if there are cleanups and in any cases as the |
| -- unwinding hook calls Unhandled_Exception_Terminate when end of |
| -- stack is reached. |
| |
| Unwind_ForcedUnwind |
| (GCC_Exception, |
| CleanupUnwind_Handler'Address, |
| System.Null_Address); |
| |
| -- We get here in case of error. The debugger has been notified before |
| -- the second step above. |
| |
| Unhandled_Except_Handler (GCC_Exception); |
| end Propagate_GCC_Exception; |
| |
| ------------------------- |
| -- Propagate_Exception -- |
| ------------------------- |
| |
| procedure Propagate_Exception (Excep : EOA) is |
| begin |
| Propagate_GCC_Exception (To_GCC_Exception (Excep.Machine_Occurrence)); |
| end Propagate_Exception; |
| |
| ----------------------------- |
| -- Set_Exception_Parameter -- |
| ----------------------------- |
| |
| procedure Set_Exception_Parameter |
| (Excep : EOA; |
| GCC_Exception : not null GCC_Exception_Access) |
| is |
| begin |
| -- Setup the exception occurrence |
| |
| if GCC_Exception.Class = GNAT_Exception_Class then |
| |
| -- From the GCC exception |
| |
| declare |
| GNAT_Occurrence : constant GNAT_GCC_Exception_Access := |
| To_GNAT_GCC_Exception (GCC_Exception); |
| begin |
| Save_Occurrence (Excep.all, GNAT_Occurrence.Occurrence); |
| end; |
| |
| else |
| -- A default one |
| |
| Set_Foreign_Occurrence (Excep, GCC_Exception.all'Address); |
| end if; |
| end Set_Exception_Parameter; |
| |
| ------------------------------ |
| -- Unhandled_Except_Handler -- |
| ------------------------------ |
| |
| procedure Unhandled_Except_Handler |
| (GCC_Exception : not null GCC_Exception_Access) |
| is |
| Excep : EOA; |
| begin |
| Excep := Setup_Current_Excep (GCC_Exception); |
| Unhandled_Exception_Terminate (Excep); |
| end Unhandled_Except_Handler; |
| |
| ------------- |
| -- EID_For -- |
| ------------- |
| |
| function EID_For |
| (GNAT_Exception : not null GNAT_GCC_Exception_Access) return Exception_Id |
| is |
| begin |
| return GNAT_Exception.Occurrence.Id; |
| end EID_For; |
| |
| ---------------------- |
| -- Foreign_Data_For -- |
| ---------------------- |
| |
| function Foreign_Data_For |
| (E : SSL.Exception_Data_Ptr) return Address |
| is |
| begin |
| return E.Foreign_Data; |
| end Foreign_Data_For; |
| |
| -------------------------- |
| -- Is_Handled_By_Others -- |
| -------------------------- |
| |
| function Is_Handled_By_Others (E : SSL.Exception_Data_Ptr) return Boolean is |
| begin |
| return not E.all.Not_Handled_By_Others; |
| end Is_Handled_By_Others; |
| |
| ------------------ |
| -- Language_For -- |
| ------------------ |
| |
| function Language_For (E : SSL.Exception_Data_Ptr) return Character is |
| begin |
| return E.all.Lang; |
| end Language_For; |
| |
| end Exception_Propagation; |
