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Diffstat (limited to 'gcc/ada/a-exextr.adb')
| -rw-r--r-- | gcc/ada/a-exextr.adb | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/gcc/ada/a-exextr.adb b/gcc/ada/a-exextr.adb new file mode 100644 index 00000000000..0ddb2934885 --- /dev/null +++ b/gcc/ada/a-exextr.adb @@ -0,0 +1,327 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- ADA.EXCEPTIONS.EXCEPTION_TRACES -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2003 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 2, 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. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- +-- MA 02111-1307, USA. -- +-- -- +-- As a special exception, if other files instantiate generics from this -- +-- unit, or you link this unit with other files to produce an executable, -- +-- this unit does not by itself cause the resulting executable to be -- +-- covered by the GNU General Public License. This exception does not -- +-- however invalidate any other reasons why the executable file might be -- +-- covered by the GNU Public License. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Unchecked_Conversion; + +separate (Ada.Exceptions) +package body Exception_Traces is + + Nline : constant String := String'(1 => ASCII.LF); + -- Convenient shortcut + + type Exception_Action is access procedure (E : Exception_Occurrence); + Global_Action : Exception_Action := null; + pragma Export + (Ada, Global_Action, "__gnat_exception_actions_global_action"); + -- Global action, executed whenever an exception is raised. Changing the + -- export name must be coordinated with code in g-excact.adb. + + Raise_Hook_Initialized : Boolean := False; + pragma Export + (Ada, Raise_Hook_Initialized, "__gnat_exception_actions_initialized"); + + function To_Action is new Unchecked_Conversion + (Raise_Action, Exception_Action); + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Notify_Exception (Excep : EOA; Is_Unhandled : Boolean); + -- Factorizes the common processing for Notify_Handled_Exception and + -- Notify_Unhandled_Exception. Is_Unhandled is set to True only in the + -- latter case because Notify_Handled_Exception may be called for an + -- actually unhandled occurrence in the Front-End-SJLJ case. + + procedure To_Stderr (S : String); + pragma Export (Ada, To_Stderr, "__gnat_to_stderr"); + -- Little routine to output string to stderr that is also used + -- in the tasking run time. + + --------------------------------- + -- Debugger Interface Routines -- + --------------------------------- + + -- The routines here are null routines that normally have no effect. + -- They are provided for the debugger to place breakpoints on their + -- entry points to get control on an exception. + + procedure Unhandled_Exception; + pragma Export (C, Unhandled_Exception, "__gnat_unhandled_exception"); + -- Hook for GDB to support "break exception unhandled". + + -- For "break exception", GDB uses __gnat_raise_nodefer_with_msg, which + -- is not in this section because it fullfills other purposes than a mere + -- debugger interface. + + -------------------------------- + -- Import Run-Time C Routines -- + -------------------------------- + + -- The purpose of the following pragma Import is to ensure that we + -- generate appropriate subprogram descriptors for all C routines in + -- the standard GNAT library that can raise exceptions. This ensures + -- that the exception propagation can properly find these routines + + pragma Propagate_Exceptions; + + procedure Unhandled_Terminate; + pragma No_Return (Unhandled_Terminate); + pragma Import (C, Unhandled_Terminate, "__gnat_unhandled_terminate"); + -- Perform system dependent shutdown code + + ---------------------- + -- Notify_Exception -- + ---------------------- + + procedure Notify_Exception (Excep : EOA; Is_Unhandled : Boolean) is + begin + -- Output the exception information required by the Exception_Trace + -- configuration. Take care not to output information about internal + -- exceptions. + + -- ??? In the Front-End ZCX case, the traceback entries we have at this + -- point only include the ones we stored while walking up the stack *up + -- to the handler*. All the frames above the subprogram in which the + -- handler is found are missing. + + if not Excep.Id.Not_Handled_By_Others + and then + (Exception_Trace = Every_Raise + or else (Exception_Trace = Unhandled_Raise and then Is_Unhandled)) + then + To_Stderr (Nline); + + if Is_Unhandled then + To_Stderr ("Unhandled "); + end if; + + To_Stderr ("Exception raised"); + To_Stderr (Nline); + To_Stderr (Tailored_Exception_Information (Excep.all)); + end if; + + -- Call the user-specific actions + -- ??? We should presumably look at the reraise status here. + + if Raise_Hook_Initialized + and then Exception_Data_Ptr (Excep.Id).Raise_Hook /= null + then + To_Action (Exception_Data_Ptr (Excep.Id).Raise_Hook) (Excep.all); + end if; + + if Global_Action /= null then + Global_Action (Excep.all); + end if; + end Notify_Exception; + + ------------------------------ + -- Notify_Handled_Exception -- + ------------------------------ + + procedure Notify_Handled_Exception is + begin + Notify_Exception (Get_Current_Excep.all, Is_Unhandled => False); + end Notify_Handled_Exception; + + -------------------------------- + -- Notify_Unhandled_Exception -- + -------------------------------- + + procedure Notify_Unhandled_Exception is + begin + Notify_Exception (Get_Current_Excep.all, Is_Unhandled => True); + Unhandled_Exception; + end Notify_Unhandled_Exception; + + ------------------------- + -- Unhandled_Exception -- + ------------------------- + + procedure Unhandled_Exception is + begin + null; + end Unhandled_Exception; + + ----------------------------------- + -- Unhandled_Exception_Terminate -- + ----------------------------------- + + type int is new Integer; + + procedure Unhandled_Exception_Terminate is + Excep : constant EOA := Save_Occurrence (Get_Current_Excep.all.all); + -- This occurrence will be used to display a message after finalization. + -- It is necessary to save a copy here, or else the designated value + -- could be overwritten if an exception is raised during finalization + -- (even if that exception is caught). + + Msg : constant String := Excep.Msg (1 .. Excep.Msg_Length); + + Max_Static_Exc_Info : constant := 1024; + -- That should be enough for most exception information cases + -- eventhough tailorising introduces some uncertainty. the + -- name+message should not exceed 320 chars, so that leaves at + -- least 35 backtrace slots (each slot needs 19 chars for + -- representing a 64 bit address). + -- And what happens on overflow ??? + + subtype Exc_Info_Type is String (1 .. Max_Static_Exc_Info); + type Str_Ptr is access Exc_Info_Type; + Exc_Info : Str_Ptr; + Exc_Info_Last : Natural := 0; + -- Buffer that is allocated to store the tailored exception + -- information while Adafinal is run. This buffer is allocated + -- on the heap only when it is needed. It is better to allocate + -- on the heap than on the stack since stack overflows are more + -- common that heap overflows. + + -- Start of processing for Unhandled_Exception_Terminate + + begin + -- First allocate & store the exception info in a buffer when + -- we know it will be needed. This needs to be done before + -- Adafinal because it implicitly uses the secondary stack. + + if Excep.Id.Full_Name.all (1) /= '_' + and then Excep.Num_Tracebacks /= 0 + then + Exc_Info := new Exc_Info_Type; + if Exc_Info /= null then + Tailored_Exception_Information + (Excep.all, Exc_Info.all, Exc_Info_Last); + end if; + end if; + + -- Let's shutdown the runtime now. The rest of the procedure + -- needs to be careful not to use anything that would require + -- runtime support. In particular, function returing strings + -- are banned since the sec stack is not functional anymore + + System.Standard_Library.Adafinal; + + -- Check for special case of raising _ABORT_SIGNAL, which is not + -- really an exception at all. We recognize this by the fact that + -- it is the only exception whose name starts with underscore. + + if Excep.Id.Full_Name.all (1) = '_' then + To_Stderr (Nline); + To_Stderr ("Execution terminated by abort of environment task"); + To_Stderr (Nline); + + -- If no tracebacks, we print the unhandled exception in the old style + -- (i.e. the style used before ZCX was implemented). We do this to + -- retain compatibility, especially with the nightly scripts, but + -- this can be removed at some point ??? + + elsif Excep.Num_Tracebacks = 0 then + To_Stderr (Nline); + To_Stderr ("raised "); + To_Stderr (Excep.Id.Full_Name.all (1 .. Excep.Id.Name_Length - 1)); + + if Msg'Length /= 0 then + To_Stderr (" : "); + To_Stderr (Msg); + end if; + + To_Stderr (Nline); + + else + -- Traceback exists + + -- Note we can have this whole information output twice if + -- this occurrence gets reraised up to here. + + To_Stderr (Nline); + To_Stderr ("Execution terminated by unhandled exception"); + To_Stderr (Nline); + To_Stderr (Exc_Info (1 .. Exc_Info_Last)); + end if; + + Unhandled_Terminate; + end Unhandled_Exception_Terminate; + + --------------- + -- To_Stderr -- + --------------- + + procedure To_Stderr (S : String) is + procedure put_char_stderr (C : int); + pragma Import (C, put_char_stderr, "put_char_stderr"); + + begin + for J in 1 .. S'Length loop + if S (J) /= ASCII.CR then + put_char_stderr (Character'Pos (S (J))); + end if; + end loop; + end To_Stderr; + + + ------------------------------------ + -- Handling GNAT.Exception_Traces -- + ------------------------------------ + + -- The bulk of exception traces output is centralized in Notify_Exception, + -- for both the Handled and Unhandled cases. Extra task specific output is + -- triggered in the task wrapper for unhandled occurrences in tasks. It is + -- not performed in this unit to avoid dragging dependencies against the + -- tasking units here. + + -- We used to rely on the output performed by Unhanded_Exception_Terminate + -- for the case of an unhandled occurrence in the environment thread, and + -- the task wrapper was responsible for the whole output in the tasking + -- case. + + -- This initial scheme had a drawback: the output from Terminate only + -- occurs after finalization is done, which means possibly never if some + -- tasks keep hanging around. + + -- The first "presumably obvious" fix consists in moving the Terminate + -- output before the finalization. It has not been retained because it + -- introduces annoying changes in output orders when the finalization + -- itself issues outputs, this also in "regular" cases not resorting to + -- Exception_Traces. + + -- Today's solution has the advantage of simplicity and better isolates + -- the Exception_Traces machinery. + + -- It currently outputs the information about unhandled exceptions twice + -- in the environment thread, once in the notification routine and once in + -- the termination routine. Avoiding the second output is possible but so + -- far has been considered undesirable. It would mean changing the order + -- of outputs between the two runs with or without exception traces, while + -- it seems preferrable to only have additional outputs in the former + -- case. + +end Exception_Traces; |