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Diffstat (limited to 'gcc/ada/libgnat/a-exexpr.adb')
| -rw-r--r-- | gcc/ada/libgnat/a-exexpr.adb | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/gcc/ada/libgnat/a-exexpr.adb b/gcc/ada/libgnat/a-exexpr.adb new file mode 100644 index 0000000..339582a --- /dev/null +++ b/gcc/ada/libgnat/a-exexpr.adb @@ -0,0 +1,439 @@ +------------------------------------------------------------------------------ +-- -- +-- 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) 1992-2017, 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 set the exception choice parameter from the + -- gcc occurrence. + + 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; |