1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . T A S K I N G . R E S T R I C T E D . S T A G E S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2019, Free Software Foundation, Inc. -- 10-- -- 11-- GNARL is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNARL was developed by the GNARL team at Florida State University. -- 28-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This is a simplified version of the System.Tasking.Stages package, 33-- intended to be used in a restricted run time. 34 35-- This package represents the high level tasking interface used by the 36-- compiler to expand Ada 95 tasking constructs into simpler run time calls 37-- (aka GNARLI, GNU Ada Run-time Library Interface) 38 39-- Note: the compiler generates direct calls to this interface, via Rtsfind. 40-- Any changes to this interface may require corresponding compiler changes 41-- in exp_ch9.adb and possibly exp_ch7.adb 42 43-- The restricted GNARLI is also composed of System.Protected_Objects and 44-- System.Protected_Objects.Single_Entry 45 46with System.Parameters; 47with System.Secondary_Stack; 48with System.Task_Info; 49 50package System.Tasking.Restricted.Stages is 51 pragma Elaborate_Body; 52 53 --------------------------------- 54 -- Compiler Interface (GNARLI) -- 55 --------------------------------- 56 57 -- The compiler will expand in the GNAT tree the following construct: 58 59 -- task type T (Discr : Integer); 60 61 -- task body T is 62 -- ...declarations, possibly some controlled... 63 -- begin 64 -- ...B...; 65 -- end T; 66 67 -- T1 : T (1); 68 69 -- as follows: 70 71 -- task type t (discr : integer); 72 -- tE : aliased boolean := false; 73 -- tZ : size_type := unspecified_size; 74 75 -- type tV (discr : integer) is limited record 76 -- _task_id : task_id; 77 -- _atcb : aliased system__tasking__ada_task_control_block (0); 78 -- end record; 79 80 -- procedure tB (_task : access tV); 81 -- freeze tV [ 82 -- procedure tVIP (_init : in out tV; _master : master_id; 83 -- _chain : in out activation_chain; _task_name : in string; 84 -- discr : integer) is 85 -- begin 86 -- _init.discr := discr; 87 -- _init._task_id := null; 88 -- system__tasking__ada_task_control_blockIP (_init._atcb, 0); 89 -- _init._task_id := _init._atcb'unchecked_access; 90 -- create_restricted_task (unspecified_priority, tZ, 91 -- unspecified_task_info, unspecified_cpu, 92 -- task_procedure_access!(tB'address), _init'address, 93 -- tE'unchecked_access, _task_name, _init._task_id); 94 -- return; 95 -- end tVIP; 96 97 -- _chain : aliased activation_chain; 98 -- activation_chainIP (_chain); 99 100 -- procedure tB (_task : access tV) is 101 -- discr : integer renames _task.discr; 102 103 -- procedure _clean is 104 -- begin 105 -- complete_restricted_task; 106 -- finalize_list (F14b); 107 -- return; 108 -- end _clean; 109 110 -- begin 111 -- ...declarations... 112 -- complete_restricted_activation; 113 -- ...B...; 114 -- return; 115 -- at end 116 -- _clean; 117 -- end tB; 118 119 -- tE := true; 120 -- t1 : t (1); 121 -- t1S : constant String := "t1"; 122 -- tIP (t1, 3, _chain, t1S, 1); 123 124 Partition_Elaboration_Policy : Character := 'C'; 125 pragma Export (C, Partition_Elaboration_Policy, 126 "__gnat_partition_elaboration_policy"); 127 -- Partition elaboration policy. Value can be either 'C' for concurrent, 128 -- which is the default or 'S' for sequential. This value can be modified 129 -- by the binder generated code, before calling elaboration code. 130 131 procedure Create_Restricted_Task 132 (Priority : Integer; 133 Stack_Address : System.Address; 134 Stack_Size : System.Parameters.Size_Type; 135 Sec_Stack_Address : System.Secondary_Stack.SS_Stack_Ptr; 136 Sec_Stack_Size : System.Parameters.Size_Type; 137 Task_Info : System.Task_Info.Task_Info_Type; 138 CPU : Integer; 139 State : Task_Procedure_Access; 140 Discriminants : System.Address; 141 Elaborated : Access_Boolean; 142 Chain : in out Activation_Chain; 143 Task_Image : String; 144 Created_Task : Task_Id); 145 -- Compiler interface only. Do not call from within the RTS. 146 -- This must be called to create a new task, when the partition 147 -- elaboration policy is not specified (or is concurrent). 148 -- 149 -- Priority is the task's priority (assumed to be in the 150 -- System.Any_Priority'Range). 151 -- 152 -- Stack_Address is the start address of the stack associated to the task, 153 -- in case it has been preallocated by the compiler; it is equal to 154 -- Null_Address when the stack needs to be allocated by the underlying 155 -- operating system. 156 -- 157 -- Stack_Size is the stack size of the task to create. 158 -- 159 -- Sec_Stack_Address is the pointer to the secondary stack created by the 160 -- compiler. If null, the secondary stack is either allocated by the binder 161 -- or the run-time. 162 -- 163 -- Secondary_Stack_Size is the secondary stack size of the task to create. 164 -- 165 -- Task_Info is the task info associated with the created task, or 166 -- Unspecified_Task_Info if none. 167 -- 168 -- CPU is the task affinity. We pass it as an Integer to avoid an explicit 169 -- dependency from System.Multiprocessors when not needed. Static range 170 -- checks are performed when analyzing the pragma, and dynamic ones are 171 -- performed before setting the affinity at run time. 172 -- 173 -- State is the compiler generated task's procedure body. 174 -- 175 -- Discriminants is a pointer to a limited record whose discriminants are 176 -- those of the task to create. This parameter should be passed as the 177 -- single argument to State. 178 -- 179 -- Elaborated is a pointer to a Boolean that must be set to true on exit 180 -- if the task could be successfully elaborated. 181 -- 182 -- Chain is a linked list of task that needs to be created. On exit, 183 -- Created_Task.Activation_Link will be Chain.T_ID, and Chain.T_ID will be 184 -- Created_Task (the created task will be linked at the front of Chain). 185 -- 186 -- Task_Image is a string created by the compiler that the run time can 187 -- store to ease the debugging and the Ada.Task_Identification facility. 188 -- 189 -- Created_Task is the resulting task. 190 -- 191 -- This procedure can raise Storage_Error if the task creation fails. 192 193 procedure Create_Restricted_Task_Sequential 194 (Priority : Integer; 195 Stack_Address : System.Address; 196 Stack_Size : System.Parameters.Size_Type; 197 Sec_Stack_Address : System.Secondary_Stack.SS_Stack_Ptr; 198 Sec_Stack_Size : System.Parameters.Size_Type; 199 Task_Info : System.Task_Info.Task_Info_Type; 200 CPU : Integer; 201 State : Task_Procedure_Access; 202 Discriminants : System.Address; 203 Elaborated : Access_Boolean; 204 Task_Image : String; 205 Created_Task : Task_Id); 206 -- Compiler interface only. Do not call from within the RTS. 207 -- This must be called to create a new task, when the sequential partition 208 -- elaboration policy is used. 209 -- 210 -- The parameters are the same as Create_Restricted_Task except there is 211 -- no Chain parameter (for the activation chain), as there is only one 212 -- global activation chain, which is declared in the body of this package. 213 214 procedure Activate_Restricted_Tasks 215 (Chain_Access : Activation_Chain_Access); 216 -- Compiler interface only. Do not call from within the RTS. 217 -- This must be called by the creator of a chain of one or more new tasks, 218 -- to activate them. The chain is a linked list that up to this point is 219 -- only known to the task that created them, though the individual tasks 220 -- are already in the All_Tasks_List. 221 -- 222 -- The compiler builds the chain in LIFO order (as a stack). Another 223 -- version of this procedure had code to reverse the chain, so as to 224 -- activate the tasks in the order of declaration. This might be nice, but 225 -- it is not needed if priority-based scheduling is supported, since all 226 -- the activated tasks synchronize on the activators lock before they start 227 -- activating and so they should start activating in priority order. 228 -- 229 -- When the partition elaboration policy is sequential, this procedure 230 -- does nothing, tasks will be activated at end of elaboration. 231 232 procedure Activate_All_Tasks_Sequential; 233 pragma Export (C, Activate_All_Tasks_Sequential, 234 "__gnat_activate_all_tasks"); 235 -- Binder interface only. Do not call from within the RTS. This must be 236 -- called an the end of the elaboration to activate all tasks, in order 237 -- to implement the sequential elaboration policy. 238 239 procedure Complete_Restricted_Activation; 240 -- Compiler interface only. Do not call from within the RTS. This should be 241 -- called from the task body at the end of the elaboration code for its 242 -- declarative part. Decrement the count of tasks to be activated by the 243 -- activator and wake it up so it can check to see if all tasks have been 244 -- activated. Except for the environment task, which should never call this 245 -- procedure, T.Activator should only be null iff T has completed 246 -- activation. 247 248 procedure Complete_Restricted_Task; 249 -- Compiler interface only. Do not call from within the RTS. This should be 250 -- called from an implicit at-end handler associated with the task body, 251 -- when it completes. From this point, the current task will become not 252 -- callable. If the current task have not completed activation, this should 253 -- be done now in order to wake up the activator (the environment task). 254 255 function Restricted_Terminated (T : Task_Id) return Boolean; 256 -- Compiler interface only. Do not call from within the RTS. This is called 257 -- by the compiler to implement the 'Terminated attribute. 258 -- 259 -- source code: 260 -- T1'Terminated 261 -- 262 -- code expansion: 263 -- restricted_terminated (t1._task_id) 264 265 procedure Finalize_Global_Tasks; 266 -- This is needed to support the compiler interface. It will only be called 267 -- by the Environment task in the binder generated file (by adafinal). 268 -- Instead, it will cause the Environment to block forever, since none of 269 -- the dependent tasks are expected to terminate 270 271end System.Tasking.Restricted.Stages; 272