| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S Y S T E M . S E C O N D A R Y _ S T A C K -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2011, 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| pragma Compiler_Unit; |
| |
| with System.Storage_Elements; |
| |
| package System.Secondary_Stack is |
| |
| package SSE renames System.Storage_Elements; |
| |
| Default_Secondary_Stack_Size : Natural := 10 * 1024; |
| -- Default size of a secondary stack. May be modified by binder -D switch |
| -- which causes the binder to generate an appropriate assignment in the |
| -- binder generated file. |
| |
| procedure SS_Init |
| (Stk : in out Address; |
| Size : Natural := Default_Secondary_Stack_Size); |
| -- Initialize the secondary stack with a main stack of the given Size. |
| -- |
| -- If System.Parameters.Sec_Stack_Percentage equals Dynamic, Stk is really |
| -- an OUT parameter that will be allocated on the heap. Then all further |
| -- allocations which do not overflow the main stack will not generate |
| -- dynamic (de)allocation calls. If the main Stack overflows, a new |
| -- chuck of at least the same size will be allocated and linked to the |
| -- previous chunk. |
| -- |
| -- Otherwise (Sec_Stack_Percentage between 0 and 100), Stk is an IN |
| -- parameter that is already pointing to a Stack_Id. The secondary stack |
| -- in this case is fixed, and any attempt to allocate more than the initial |
| -- size will result in a Storage_Error being raised. |
| -- |
| -- Note: the reason that Stk is passed is that SS_Init is called before |
| -- the proper interface is established to obtain the address of the |
| -- stack using System.Soft_Links.Get_Sec_Stack_Addr. |
| |
| procedure SS_Allocate |
| (Addr : out Address; |
| Storage_Size : SSE.Storage_Count); |
| -- Allocate enough space for a 'Storage_Size' bytes object with Maximum |
| -- alignment. The address of the allocated space is returned in Addr. |
| |
| procedure SS_Free (Stk : in out Address); |
| -- Release the memory allocated for the Secondary Stack. That is |
| -- to say, all the allocated chunks. Upon return, Stk will be set |
| -- to System.Null_Address. |
| |
| type Mark_Id is private; |
| -- Type used to mark the stack for mark/release processing |
| |
| function SS_Mark return Mark_Id; |
| -- Return the Mark corresponding to the current state of the stack |
| |
| procedure SS_Release (M : Mark_Id); |
| -- Restore the state of the stack corresponding to the mark M. If an |
| -- additional chunk have been allocated, it will never be freed during a |
| -- ??? missing comment here |
| |
| function SS_Get_Max return Long_Long_Integer; |
| -- Return maximum used space in storage units for the current secondary |
| -- stack. For a dynamically allocated secondary stack, the returned |
| -- result is always -1. For a statically allocated secondary stack, |
| -- the returned value shows the largest amount of space allocated so |
| -- far during execution of the program to the current secondary stack, |
| -- i.e. the secondary stack for the current task. |
| |
| generic |
| with procedure Put_Line (S : String); |
| procedure SS_Info; |
| -- Debugging procedure used to print out secondary Stack allocation |
| -- information. This procedure is generic in order to avoid a direct |
| -- dependance on a particular IO package. |
| |
| private |
| SS_Pool : Integer; |
| -- Unused entity that is just present to ease the sharing of the pool |
| -- mechanism for specific allocation/deallocation in the compiler |
| |
| type SS_Ptr is new SSE.Integer_Address; |
| -- Stack pointer value for secondary stack |
| |
| type Mark_Id is record |
| Sstk : System.Address; |
| Sptr : SS_Ptr; |
| end record; |
| -- A mark value contains the address of the secondary stack structure, |
| -- as returned by System.Soft_Links.Get_Sec_Stack_Addr, and a stack |
| -- pointer value corresponding to the point of the mark call. |
| |
| end System.Secondary_Stack; |
