| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- SYSTEM.MACHINE_STATE_OPERATIONS -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1999-2005 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, 51 Franklin Street, Fifth Floor, -- |
| -- Boston, MA 02110-1301, 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| pragma Polling (Off); |
| -- We must turn polling off for this unit, because otherwise we get |
| -- elaboration circularities with System.Exception_Tables. |
| |
| with System.Storage_Elements; |
| |
| package System.Machine_State_Operations is |
| |
| subtype Code_Loc is System.Address; |
| -- Code location used in building exception tables and for call |
| -- addresses when propagating an exception (also traceback table) |
| -- Values of this type are created by using Label'Address or |
| -- extracted from machine states using Get_Code_Loc. |
| |
| type Machine_State is new System.Address; |
| -- The table based exception handling approach (see a-except.adb) isolates |
| -- the target dependent aspects using an abstract data type interface |
| -- to the type Machine_State, which is represented as a System.Address |
| -- value (presumably implemented as a pointer to an appropriate record |
| -- structure). |
| |
| function Machine_State_Length return System.Storage_Elements.Storage_Offset; |
| -- Function to determine the length of the Storage_Array needed to hold |
| -- a machine state. The machine state will always be maximally aligned. |
| -- The value returned is a constant that will be used to allocate space |
| -- for a machine state value. |
| |
| function Allocate_Machine_State return Machine_State; |
| -- Allocate the required space for a Machine_State |
| |
| procedure Free_Machine_State (M : in out Machine_State); |
| -- Free the dynamic memory taken by Machine_State |
| |
| -- The initial value of type Machine_State is created by the low level |
| -- routine that actually raises an exception using the special builtin |
| -- _builtin_machine_state. This value will typically encode the value |
| -- of the program counter, and relevant registers. The following |
| -- operations are defined on Machine_State values: |
| |
| function Get_Code_Loc (M : Machine_State) return Code_Loc; |
| -- This function extracts the program counter value from a machine |
| -- state, which the caller uses for searching the exception tables, |
| -- and also for recording entries in the traceback table. The call |
| -- returns a value of Null_Loc if the machine state represents the |
| -- outer level, or some other frame for which no information can be |
| -- provided. |
| |
| procedure Pop_Frame (M : Machine_State); |
| -- This procedure pops the machine state M so that it represents the |
| -- call point, as though the current subprogram had returned. It |
| -- changes only the value referenced by M, and does not affect |
| -- the current stack environment. |
| |
| function Fetch_Code (Loc : Code_Loc) return Code_Loc; |
| -- Some architectures (notably VMS) use a descriptor to describe |
| -- a subprogram address. This function computes the actual starting |
| -- address of the code from Loc. |
| -- Do not add pragma Inline, see 9116-002. |
| -- ??? This function will go away when 'Code_Address is fixed on VMS. |
| |
| procedure Set_Machine_State (M : Machine_State); |
| -- This routine sets M from the current machine state. It is called |
| -- when an exception is initially signalled to initialize the state. |
| |
| end System.Machine_State_Operations; |
