------------------------------------------------------------------------------ -- -- -- 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) 1992-2013, 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 -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ pragma Compiler_Unit_Warning; 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;