------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S Y S T E M . R I D E N T -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2012, 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. -- -- -- ------------------------------------------------------------------------------ -- This package defines the set of restriction identifiers. It is a generic -- package that is instantiated by the compiler/binder in package Rident, and -- is instantiated in package System.Restrictions for use at run-time. -- The reason that we make this a generic package is so that in the case of -- the instantiation in Rident for use at compile time and bind time, we can -- generate normal image tables for the enumeration types, which are needed -- for diagnostic and informational messages. At run-time we really do not -- want to waste the space for these image tables, and they are not needed, -- so we can do the instantiation under control of Discard_Names to remove -- the tables. --------------------------------------------------- -- Note On Compile/Run-Time Consistency Checking -- --------------------------------------------------- -- This unit is with'ed by the run-time (to make System.Restrictions which is -- used for run-time access to restriction information), by the compiler (to -- determine what restrictions are implemented and what their category is) and -- by the binder (in processing ali files, and generating the information used -- at run-time to access restriction information). -- Normally the version of System.Rident referenced in all three contexts -- should be the same. However, problems could arise in certain inconsistent -- builds that used inconsistent versions of the compiler and run-time. This -- sort of thing is not strictly correct, but it does arise when short-cuts -- are taken in build procedures. -- Previously, this kind of inconsistency could cause a significant problem. -- If versions of System.Rident accessed by the compiler and binder differed, -- then the binder could fail to recognize the R (restrictions line) in the -- ali file, leading to bind errors when restrictions were added or removed. -- The latest implementation avoids both this problem by using a named -- scheme for recording restrictions, rather than a positional scheme which -- fails completely if restrictions are added or subtracted. Now the worst -- that happens at bind time in incosistent builds is that unrecognized -- restrictions are ignored, and the consistency checking for restrictions -- might be incomplete, which is no big deal. pragma Compiler_Unit; generic package System.Rident is pragma Preelaborate; -- The following enumeration type defines the set of restriction -- identifiers that are implemented in GNAT. -- To add a new restriction identifier, add an entry with the name to be -- used in the pragma, and add calls to the Restrict.Check_Restriction -- routine as appropriate. type Restriction_Id is -- The following cases are checked for consistency in the binder. The -- binder will check that every unit either has the restriction set, or -- does not violate the restriction. (Simple_Barriers, -- GNAT (Ravenscar) No_Abort_Statements, -- (RM D.7(5), H.4(3)) No_Access_Subprograms, -- (RM H.4(17)) No_Allocators, -- (RM H.4(7)) No_Allocators_After_Elaboration, -- Ada 2012 (RM D.7(19.1/2)) No_Anonymous_Allocators, -- Ada 2012 (RM H.4(8/1)) No_Asynchronous_Control, -- (RM J.13(3/2) No_Calendar, -- GNAT No_Default_Stream_Attributes, -- Ada 2012 (RM 13.12.1(4/2)) No_Delay, -- (RM H.4(21)) No_Direct_Boolean_Operators, -- GNAT No_Dispatch, -- (RM H.4(19)) No_Dispatching_Calls, -- GNAT No_Dynamic_Attachment, -- GNAT No_Dynamic_Priorities, -- (RM D.9(9)) No_Enumeration_Maps, -- GNAT No_Entry_Calls_In_Elaboration_Code, -- GNAT No_Entry_Queue, -- GNAT (Ravenscar) No_Exception_Handlers, -- GNAT No_Exception_Propagation, -- GNAT No_Exception_Registration, -- GNAT No_Exceptions, -- (RM H.4(12)) No_Finalization, -- GNAT No_Fixed_Point, -- (RM H.4(15)) No_Floating_Point, -- (RM H.4(14)) No_IO, -- (RM H.4(20)) No_Implicit_Conditionals, -- GNAT No_Implicit_Dynamic_Code, -- GNAT No_Implicit_Heap_Allocations, -- (RM D.8(8), H.4(3)) No_Implicit_Loops, -- GNAT No_Initialize_Scalars, -- GNAT No_Local_Allocators, -- (RM H.4(8)) No_Local_Timing_Events, -- (RM D.7(10.2/2)) No_Local_Protected_Objects, -- GNAT No_Nested_Finalization, -- (RM D.7(4)) No_Protected_Type_Allocators, -- GNAT No_Protected_Types, -- (RM H.4(5)) No_Recursion, -- (RM H.4(22)) No_Reentrancy, -- (RM H.4(23)) No_Relative_Delay, -- GNAT (Ravenscar) No_Requeue_Statements, -- GNAT No_Secondary_Stack, -- GNAT No_Select_Statements, -- GNAT (Ravenscar) No_Specific_Termination_Handlers, -- (RM D.7(10.7/2)) No_Standard_Storage_Pools, -- GNAT No_Stream_Optimizations, -- GNAT No_Streams, -- GNAT No_Task_Allocators, -- (RM D.7(7)) No_Task_Attributes_Package, -- GNAT No_Task_Hierarchy, -- (RM D.7(3), H.4(3)) No_Task_Termination, -- GNAT (Ravenscar) No_Tasking, -- GNAT No_Terminate_Alternatives, -- (RM D.7(6)) No_Unchecked_Access, -- (RM H.4(18)) No_Unchecked_Conversion, -- (RM J.13(4/2)) No_Unchecked_Deallocation, -- (RM J.13(5/2)) Static_Priorities, -- GNAT Static_Storage_Size, -- GNAT -- The following require consistency checking with special rules. See -- individual routines in unit Bcheck for details of what is required. No_Default_Initialization, -- GNAT -- The following cases do not require consistency checking and if used -- as a configuration pragma within a specific unit, apply only to that -- unit (e.g. if used in the package spec, do not apply to the body) -- Note: No_Elaboration_Code is handled specially. Like the other -- non-partition-wide restrictions, it can only be set in a unit that -- is part of the extended main source unit (body/spec/subunits). But -- it is sticky, in that if it is found anywhere within any of these -- units, it applies to all units in this extended main source. Immediate_Reclamation, -- (RM H.4(10)) No_Implementation_Aspect_Specifications, -- Ada 2012 AI-241 No_Implementation_Attributes, -- Ada 2005 AI-257 No_Implementation_Identifiers, -- Ada 2012 AI-246 No_Implementation_Pragmas, -- Ada 2005 AI-257 No_Implementation_Restrictions, -- GNAT No_Implementation_Units, -- Ada 2012 AI-242 No_Implicit_Aliasing, -- GNAT No_Elaboration_Code, -- GNAT No_Obsolescent_Features, -- Ada 2005 AI-368 No_Wide_Characters, -- GNAT SPARK, -- GNAT -- The following cases require a parameter value -- The following entries are fully checked at compile/bind time, which -- means that the compiler can in general tell the minimum value which -- could be used with a restrictions pragma. The binder can deduce the -- appropriate minimum value for the partition by taking the maximum -- value required by any unit. Max_Protected_Entries, -- (RM D.7(14)) Max_Select_Alternatives, -- (RM D.7(12)) Max_Task_Entries, -- (RM D.7(13), H.4(3)) -- The following entries are also fully checked at compile/bind time, -- and the compiler can also at least in some cases tell the minimum -- value which could be used with a restriction pragma. The difference -- is that the contributions are additive, so the binder deduces this -- value by adding the unit contributions. Max_Tasks, -- (RM D.7(19), H.4(3)) -- The following entries are checked at compile time only for zero/ -- nonzero entries. This means that the compiler can tell at compile -- time if a restriction value of zero is (would be) violated, but that -- the compiler cannot distinguish between different non-zero values. Max_Asynchronous_Select_Nesting, -- (RM D.7(18), H.4(3)) Max_Entry_Queue_Length, -- GNAT -- The remaining entries are not checked at compile/bind time Max_Storage_At_Blocking, -- (RM D.7(17)) Not_A_Restriction_Id); -- Synonyms permitted for historical purposes of compatibility. -- Must be coordinated with Restrict.Process_Restriction_Synonym. Boolean_Entry_Barriers : Restriction_Id renames Simple_Barriers; Max_Entry_Queue_Depth : Restriction_Id renames Max_Entry_Queue_Length; No_Dynamic_Interrupts : Restriction_Id renames No_Dynamic_Attachment; No_Requeue : Restriction_Id renames No_Requeue_Statements; No_Task_Attributes : Restriction_Id renames No_Task_Attributes_Package; subtype All_Restrictions is Restriction_Id range Simple_Barriers .. Max_Storage_At_Blocking; -- All restrictions (excluding only Not_A_Restriction_Id) subtype All_Boolean_Restrictions is Restriction_Id range Simple_Barriers .. SPARK; -- All restrictions which do not take a parameter subtype Partition_Boolean_Restrictions is All_Boolean_Restrictions range Simple_Barriers .. Static_Storage_Size; -- Boolean restrictions that are checked for partition consistency. -- Note that all parameter restrictions are checked for partition -- consistency by default, so this distinction is only needed in the -- case of Boolean restrictions. subtype Cunit_Boolean_Restrictions is All_Boolean_Restrictions range Immediate_Reclamation .. SPARK; -- Boolean restrictions that are not checked for partition consistency -- and that thus apply only to the current unit. Note that for these -- restrictions, the compiler does not apply restrictions found in -- with'ed units, parent specs etc. to the main unit, and vice versa. subtype All_Parameter_Restrictions is Restriction_Id range Max_Protected_Entries .. Max_Storage_At_Blocking; -- All restrictions that take a parameter subtype Checked_Parameter_Restrictions is All_Parameter_Restrictions range Max_Protected_Entries .. Max_Entry_Queue_Length; -- These are the parameter restrictions that can be at least partially -- checked at compile/binder time. Minimally, the compiler can detect -- violations of a restriction pragma with a value of zero reliably. subtype Checked_Max_Parameter_Restrictions is Checked_Parameter_Restrictions range Max_Protected_Entries .. Max_Task_Entries; -- Restrictions with parameters that can be checked in some cases by -- maximizing among statically detected instances where the compiler -- can determine the count. subtype Checked_Add_Parameter_Restrictions is Checked_Parameter_Restrictions range Max_Tasks .. Max_Tasks; -- Restrictions with parameters that can be checked in some cases by -- summing the statically detected instances where the compiler can -- determine the count. subtype Checked_Val_Parameter_Restrictions is Checked_Parameter_Restrictions range Max_Protected_Entries .. Max_Tasks; -- Restrictions with parameter where the count is known at least in some -- cases by the compiler/binder. subtype Checked_Zero_Parameter_Restrictions is Checked_Parameter_Restrictions range Max_Asynchronous_Select_Nesting .. Max_Entry_Queue_Length; -- Restrictions with parameters where the compiler can detect the use of -- the feature, and hence violations of a restriction specifying a value -- of zero, but cannot detect specific values other than zero/nonzero. subtype Unchecked_Parameter_Restrictions is All_Parameter_Restrictions range Max_Storage_At_Blocking .. Max_Storage_At_Blocking; -- Restrictions with parameters where the compiler cannot ever detect -- corresponding compile time usage, so the binder and compiler never -- detect violations of any restriction. ------------------------------------- -- Restriction Status Declarations -- ------------------------------------- -- The following declarations are used to record the current status or -- restrictions (for the current unit, or related units, at compile time, -- and for all units in a partition at bind time or run time). type Restriction_Flags is array (All_Restrictions) of Boolean; type Restriction_Values is array (All_Parameter_Restrictions) of Natural; type Parameter_Flags is array (All_Parameter_Restrictions) of Boolean; type Restrictions_Info is record Set : Restriction_Flags; -- An entry is True in the Set array if a restrictions pragma has been -- encountered for the given restriction. If the value is True for a -- parameter restriction, then the corresponding entry in the Value -- array gives the minimum value encountered for any such restriction. Value : Restriction_Values; -- If the entry for a parameter restriction in Set is True (i.e. a -- restrictions pragma for the restriction has been encountered), then -- the corresponding entry in the Value array is the minimum value -- specified by any such restrictions pragma. Note that a restrictions -- pragma specifying a value greater than Int'Last is simply ignored. Violated : Restriction_Flags; -- An entry is True in the violations array if the compiler has detected -- a violation of the restriction. For a parameter restriction, the -- Count and Unknown arrays have additional information. Count : Restriction_Values; -- If an entry for a parameter restriction is True in Violated, the -- corresponding entry in the Count array may record additional -- information. If the actual minimum count is known (by taking -- maximums, or sums, depending on the restriction), it will be -- recorded in this array. If not, then the value will remain zero. -- The value is also zero for a non-violated restriction. Unknown : Parameter_Flags; -- If an entry for a parameter restriction is True in Violated, the -- corresponding entry in the Unknown array may record additional -- information. If the actual count is not known by the compiler (but -- is known to be non-zero), then the entry in Unknown will be True. -- This indicates that the value in Count is not known to be exact, -- and the actual violation count may be higher. -- Note: If Violated (K) is True, then either Count (K) > 0 or -- Unknown (K) = True. It is possible for both these to be set. -- For example, if Count (K) = 3 and Unknown (K) is True, it means -- that the actual violation count is at least 3 but might be higher. end record; No_Restrictions : constant Restrictions_Info := (Set => (others => False), Value => (others => 0), Violated => (others => False), Count => (others => 0), Unknown => (others => False)); -- Used to initialize Restrictions_Info variables ---------------------------------- -- Profile Definitions and Data -- ---------------------------------- -- Note: to add a profile, modify the following declarations appropriately, -- add Name_xxx to Snames, and add a branch to the conditions for pragmas -- Profile and Profile_Warnings in the body of Sem_Prag. type Profile_Name is (No_Profile, No_Implementation_Extensions, Ravenscar, Restricted); -- Names of recognized profiles. No_Profile is used to indicate that a -- restriction came from pragma Restrictions[_Warning], as opposed to -- pragma Profile[_Warning]. subtype Profile_Name_Actual is Profile_Name range No_Implementation_Extensions .. Restricted; -- Actual used profile names type Profile_Data is record Set : Restriction_Flags; -- Set to True if given restriction must be set for the profile, and -- False if it need not be set (False does not mean that it must not be -- set, just that it need not be set). If the flag is True for a -- parameter restriction, then the Value array gives the maximum value -- permitted by the profile. Value : Restriction_Values; -- An entry in this array is meaningful only if the corresponding flag -- in Set is True. In that case, the value in this array is the maximum -- value of the parameter permitted by the profile. end record; Profile_Info : constant array (Profile_Name_Actual) of Profile_Data := (No_Implementation_Extensions => -- Restrictions for Restricted profile (Set => (No_Implementation_Aspect_Specifications => True, No_Implementation_Attributes => True, No_Implementation_Identifiers => True, No_Implementation_Pragmas => True, No_Implementation_Units => True, others => False), -- Value settings for Restricted profile (none Value => (others => 0)), -- Restricted Profile Restricted => -- Restrictions for Restricted profile (Set => (No_Abort_Statements => True, No_Asynchronous_Control => True, No_Dynamic_Attachment => True, No_Dynamic_Priorities => True, No_Entry_Queue => True, No_Local_Protected_Objects => True, No_Protected_Type_Allocators => True, No_Requeue_Statements => True, No_Task_Allocators => True, No_Task_Attributes_Package => True, No_Task_Hierarchy => True, No_Terminate_Alternatives => True, Max_Asynchronous_Select_Nesting => True, Max_Protected_Entries => True, Max_Select_Alternatives => True, Max_Task_Entries => True, others => False), -- Value settings for Restricted profile Value => (Max_Asynchronous_Select_Nesting => 0, Max_Protected_Entries => 1, Max_Select_Alternatives => 0, Max_Task_Entries => 0, others => 0)), -- Ravenscar Profile -- Note: the table entries here only represent the -- required restriction profile for Ravenscar. The -- full Ravenscar profile also requires: -- pragma Dispatching_Policy (FIFO_Within_Priorities); -- pragma Locking_Policy (Ceiling_Locking); -- pragma Detect_Blocking Ravenscar => -- Restrictions for Ravenscar = Restricted profile .. (Set => (No_Abort_Statements => True, No_Asynchronous_Control => True, No_Dynamic_Attachment => True, No_Dynamic_Priorities => True, No_Entry_Queue => True, No_Local_Protected_Objects => True, No_Protected_Type_Allocators => True, No_Requeue_Statements => True, No_Task_Allocators => True, No_Task_Attributes_Package => True, No_Task_Hierarchy => True, No_Terminate_Alternatives => True, Max_Asynchronous_Select_Nesting => True, Max_Protected_Entries => True, Max_Select_Alternatives => True, Max_Task_Entries => True, -- plus these additional restrictions: No_Calendar => True, No_Implicit_Heap_Allocations => True, No_Relative_Delay => True, No_Select_Statements => True, No_Task_Termination => True, Simple_Barriers => True, others => False), -- Value settings for Ravenscar (same as Restricted) Value => (Max_Asynchronous_Select_Nesting => 0, Max_Protected_Entries => 1, Max_Select_Alternatives => 0, Max_Task_Entries => 0, others => 0))); end System.Rident;