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gcc/gcc/ada/restrict.ads
Arnaud Charlet 2cbac6c692 [multiple changes] 
2013-07-08  Robert Dewar  <dewar@adacore.com>

	* sem.ads: Minor comment updates.
	* s-restri.ads, exp_ch6.adb, lib-load.ads, exp_ch3.adb, sem_ch10.adb:
	Minor reformatting.

2013-07-08  Robert Dewar  <dewar@adacore.com>

	* exp_attr.adb (Expand_N_Attribute_Reference): Add dummy entry
	for Restriction_Set.
	* gnat_rm.texi: Add missing menu entry for Attribute Ref Add
	documentation for attribute Restriction_Set.
	* lib-writ.adb (Write_With_Lines): Generate special W lines
	for Restriction_Set.
	* lib-writ.ads: Document special use of W lines for
	Restriction_Set.
	* lib.ads (Restriction_Set_Dependences): New table.
	* par-ch4.adb (Is_Parameterless_Attribute): Add Loop_Entry to
	list (Scan_Name_Extension_Apostrophe): Remove kludge test for
	Loop_Entry (Scan_Name_Extension_Apostrophe): Handle No_Dependence
	for Restricton_Set.
	* restrict.adb (Check_SPARK_Restriction): Put in Alfa order
	(OK_No_Dependence_Unit_Name): New function.
	* restrict.ads (OK_No_Dependence_Unit_Name): New function.
	* rtsfind.adb: Minor reformatting Minor code reorganization.
	* sem_attr.adb (Analyze_Attribute): Add processing for
	Restriction_Set.
	* sem_prag.adb (Process_Restrictions_Or_Restriction_Warnings):
	Remove Check_Unit_Name and use new function
	OK_No_Dependence_Unit_Name instead.
	* sinfo.ads: Minor comment updates.
	* snames.ads-tmpl: Add entry for Restriction_Set attribute.

2013-07-08  Hristian Kirtchev  <kirtchev@adacore.com>

	* exp_ch4.adb (Apply_Accessibility_Check): Remove local constant
	Pool_Id and local variable Free_Stmt. Do not deallocate the faulty
	object as "free" is not available on all targets/profiles.

2013-07-08  Robert Dewar  <dewar@adacore.com>

	* sem_ch13.adb (Analyze_Aspect_Specifications): Handle
	Storage_Size aspect for task type in case discriminant is
	referenced.
	(Analyze_Attribute_Definition_Clause): Do not flag Storage_Size
	attribute definition clause as obsolescent if from aspect.

From-SVN: r200771
2013-07-08 10:15:25 +02:00

498 lines
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Ada
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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- R E S T R I C T --
-- --
-- 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. 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 COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package deals with the implementation of the Restrictions pragma
with Namet; use Namet;
with Rident; use Rident;
with Table;
with Types; use Types;
with Uintp; use Uintp;
package Restrict is
Restrictions : Restrictions_Info := No_Restrictions;
-- This variable records restrictions found in any units in the main
-- extended unit, and in the case of restrictions checked for partition
-- consistency, restrictions found in any with'ed units, parent specs
-- etc., since we may as well check as much as we can at compile time.
-- These variables should not be referenced directly by clients. Instead
-- use Check_Restriction to record a violation of a restriction, and
-- Restriction_Active to test if a given restriction is active.
Restrictions_Loc : array (All_Restrictions) of Source_Ptr :=
(others => No_Location);
-- Locations of Restrictions pragmas for error message purposes.
-- Valid only if corresponding entry in Restrictions is set. A value
-- of No_Location is used for implicit restrictions set by another
-- pragma, and a value of System_Location is used for restrictions
-- set from package Standard by the processing in Targparm.
Restriction_Profile_Name : array (All_Restrictions) of Profile_Name;
-- Entries in this array are valid only if the corresponding restriction
-- in Restrictions set. The value is the corresponding profile name if the
-- restriction was set by a Profile or Profile_Warnings pragma. The value
-- is No_Profile in all other cases.
Main_Restrictions : Restrictions_Info := No_Restrictions;
-- This variable records only restrictions found in any units of the
-- main extended unit. These are the variables used for ali file output,
-- since we want the binder to be able to accurately diagnose inter-unit
-- restriction violations.
Restriction_Warnings : Rident.Restriction_Flags := (others => False);
-- If one of these flags is set, then it means that violation of the
-- corresponding restriction results only in a warning message, not
-- in an error message, and the restriction is not otherwise enforced.
-- Note that the flags in Restrictions are set to indicate that the
-- restriction is set in this case, but Main_Restrictions is never
-- set if Restriction_Warnings is set, so this does not look like a
-- restriction to the binder.
-- The following declarations establish a mapping between restriction
-- identifiers, and the names of corresponding restriction library units.
type Unit_Entry is record
Res_Id : Restriction_Id;
Filenm : String (1 .. 8);
end record;
Unit_Array : constant array (Positive range <>) of Unit_Entry := (
(No_Asynchronous_Control, "a-astaco"),
(No_Calendar, "a-calend"),
(No_Calendar, "calendar"),
(No_Delay, "a-calend"),
(No_Delay, "calendar"),
(No_Dynamic_Priorities, "a-dynpri"),
(No_Finalization, "a-finali"),
(No_IO, "a-direio"),
(No_IO, "directio"),
(No_IO, "a-sequio"),
(No_IO, "sequenio"),
(No_IO, "a-ststio"),
(No_IO, "a-textio"),
(No_IO, "text_io "),
(No_IO, "a-witeio"),
(No_Task_Attributes_Package, "a-tasatt"),
(No_Unchecked_Conversion, "a-unccon"),
(No_Unchecked_Conversion, "unchconv"),
(No_Unchecked_Deallocation, "a-uncdea"),
(No_Unchecked_Deallocation, "unchdeal"));
-- The following map has True for all GNAT-defined Restrictions. It is used
-- to implement pragma Restrictions (No_Implementation_Restrictions) (which
-- is why this restriction itself is excluded from the list).
Implementation_Restriction : array (All_Restrictions) of Boolean :=
(Simple_Barriers => True,
No_Calendar => True,
No_Default_Initialization => True,
No_Direct_Boolean_Operators => True,
No_Dispatching_Calls => True,
No_Dynamic_Attachment => True,
No_Elaboration_Code => True,
No_Enumeration_Maps => True,
No_Entry_Calls_In_Elaboration_Code => True,
No_Entry_Queue => True,
No_Exception_Handlers => True,
No_Exception_Propagation => True,
No_Exception_Registration => True,
No_Finalization => True,
No_Implementation_Attributes => True,
No_Implementation_Pragmas => True,
No_Implicit_Conditionals => True,
No_Implicit_Aliasing => True,
No_Implicit_Dynamic_Code => True,
No_Implicit_Loops => True,
No_Initialize_Scalars => True,
No_Local_Protected_Objects => True,
No_Protected_Type_Allocators => True,
No_Relative_Delay => True,
No_Requeue_Statements => True,
No_Secondary_Stack => True,
No_Select_Statements => True,
No_Standard_Storage_Pools => True,
No_Stream_Optimizations => True,
No_Streams => True,
No_Task_Attributes_Package => True,
No_Task_Termination => True,
No_Tasking => True,
No_Wide_Characters => True,
Static_Priorities => True,
Static_Storage_Size => True,
SPARK_05 => True,
others => False);
-- The following table records entries made by Restrictions pragmas
-- that specify a parameter for No_Dependence. Each such pragma makes
-- an entry in this table.
-- Note: we have chosen to implement this restriction in the "syntactic"
-- form, where we do not check that the named package is a language defined
-- package, but instead we allow arbitrary package names. The discussion of
-- this issue is not complete in the ARG, but the sense seems to be leaning
-- in this direction, which makes more sense to us, since it is much more
-- useful, and much easier to implement.
type ND_Entry is record
Unit : Node_Id;
-- The unit parameter from the No_Dependence pragma
Warn : Boolean;
-- True if from Restriction_Warnings, False if from Restrictions
Profile : Profile_Name;
-- Set to name of profile from which No_Dependence entry came, or to
-- No_Profile if a pragma Restriction set the No_Dependence entry.
end record;
package No_Dependences is new Table.Table (
Table_Component_Type => ND_Entry,
Table_Index_Type => Int,
Table_Low_Bound => 0,
Table_Initial => 200,
Table_Increment => 200,
Table_Name => "Name_No_Dependences");
-----------------
-- Subprograms --
-----------------
-- Note: several of these subprograms can generate error messages (e.g.
-- Check_Restriction). These routines should be called in the analyzer
-- rather than the expander, so that the associated error messages are
-- correctly generated in semantics only (-gnatc) mode.
function Abort_Allowed return Boolean;
pragma Inline (Abort_Allowed);
-- Tests to see if abort is allowed by the current restrictions settings.
-- For abort to be allowed, either No_Abort_Statements must be False,
-- or Max_Asynchronous_Select_Nesting must be non-zero.
procedure Check_Compiler_Unit (N : Node_Id);
-- If unit N is in a unit that has a pragma Compiler_Unit, then a message
-- is posted on node N noting use of a construct that is not permitted in
-- the compiler.
procedure Check_Restricted_Unit (U : Unit_Name_Type; N : Node_Id);
-- Checks if loading of unit U is prohibited by the setting of some
-- restriction (e.g. No_IO restricts the loading of unit Ada.Text_IO).
-- If a restriction exists post error message at the given node.
procedure Check_Restriction
(Msg_Issued : out Boolean;
R : Restriction_Id;
N : Node_Id;
V : Uint := Uint_Minus_1);
-- Checks that the given restriction is not set, and if it is set, an
-- appropriate message is posted on the given node, in which case
-- Msg_Issued is set to True (and False otherwise). Also records the
-- violation in the appropriate internal arrays. Note that it is mandatory
-- to always use this routine to check if a restriction is violated. Such
-- checks must never be done directly by the caller, since otherwise
-- violations in the absence of restrictions are not properly recorded. The
-- value of V is relevant only for parameter restrictions, and in this case
-- indicates the exact count for the violation. If the exact count is not
-- known, V is left at its default of -1 which indicates an unknown count.
procedure Check_Restriction
(R : Restriction_Id;
N : Node_Id;
V : Uint := Uint_Minus_1);
-- Wrapper on Check_Restriction with Msg_Issued, with the out-parameter
-- being ignored here.
procedure Check_Restriction_No_Use_Of_Attribute (N : Node_Id);
-- N is the node of an attribute definition clause. An error message
-- (warning) will be issued if a restriction (warning) was previously set
-- for this attribute using Set_No_Use_Of_Attribute.
procedure Check_Restriction_No_Use_Of_Pragma (N : Node_Id);
-- N is the node of a pragma. An error message (warning) will be issued
-- if a restriction (warning) was previously set for this pragma using
-- Set_No_Use_Of_Pragma.
procedure Check_Restriction_No_Dependence (U : Node_Id; Err : Node_Id);
-- Called when a dependence on a unit is created (either implicitly, or by
-- an explicit WITH clause). U is a node for the unit involved, and Err is
-- the node to which an error will be attached if necessary.
procedure Check_Restriction_No_Specification_Of_Aspect (N : Node_Id);
-- N is the node id for an N_Aspect_Specification. An error message
-- (warning) will be issued if a restriction (warning) was previous set
-- for this aspect using Set_No_Specification_Of_Aspect.
procedure Check_Elaboration_Code_Allowed (N : Node_Id);
-- Tests to see if elaboration code is allowed by the current restrictions
-- settings. This function is called by Gigi when it needs to define an
-- elaboration routine. If elaboration code is not allowed, an error
-- message is posted on the node given as argument.
procedure Check_SPARK_Restriction
(Msg : String;
N : Node_Id;
Force : Boolean := False);
-- Node N represents a construct not allowed in formal mode. If this is
-- a source node, or if the restriction is forced (Force = True), and
-- the SPARK_05 restriction is set, then an error is issued on N. Msg
-- is appended to the restriction failure message.
procedure Check_SPARK_Restriction (Msg1, Msg2 : String; N : Node_Id);
-- Same as Check_SPARK_Restriction except there is a continuation message
-- Msg2 following the initial message Msg1.
procedure Check_No_Implicit_Aliasing (Obj : Node_Id);
-- Obj is a node for which Is_Aliased_View is True, which is being used in
-- a context (e.g. 'Access) where no implicit aliasing is allowed if the
-- restriction No_Implicit_Aliasing is set. This procedure checks for the
-- case where the restriction is active and Obj does not meet the required
-- rules for avoiding implicit aliases, and issues a restriction message.
procedure Check_Implicit_Dynamic_Code_Allowed (N : Node_Id);
-- Tests to see if dynamic code generation (dynamically generated
-- trampolines, in particular) is allowed by the current restrictions
-- settings. This function is called by Gigi when it needs to generate code
-- that generates a trampoline. If not allowed, an error message is posted
-- on the node given as argument.
procedure Check_No_Implicit_Heap_Alloc (N : Node_Id);
-- Equivalent to Check_Restriction (No_Implicit_Heap_Allocations, N).
-- Provided for easy use by back end, which has to check this restriction.
procedure Check_Obsolescent_2005_Entity (E : Entity_Id; N : Node_Id);
-- This routine checks if the entity E is one of the obsolescent entries
-- in Ada.Characters.Handling in Ada 2005 and No_Obsolescent_Features
-- restriction is active. If so an appropriate message is given. N is
-- the node on which the message is to be placed. It's a bit kludgy to
-- have this highly specialized routine rather than some wonderful general
-- mechanism (e.g. a special pragma) to handle this case, but there are
-- only six cases, and it is not worth the effort to do something general.
procedure Check_Wide_Character_Restriction (E : Entity_Id; N : Node_Id);
-- This procedure checks if the No_Wide_Character restriction is active,
-- and if so, if N Comes_From_Source, and the root type of E is one of
-- [Wide_]Wide_Character or [Wide_]Wide_String, then the restriction
-- violation is recorded, and an appropriate message given.
function Get_Restriction_Id
(N : Name_Id) return Restriction_Id;
-- Given an identifier name, determines if it is a valid restriction
-- identifier, and if so returns the corresponding Restriction_Id value,
-- otherwise returns Not_A_Restriction_Id.
function OK_No_Dependence_Unit_Name (N : Node_Id) return Boolean;
-- Used in checking No_Dependence argument of pragma Restrictions or
-- pragma Restrictions_Warning, or attribute Restriction_Set. Returns
-- True if N has the proper form for a unit name, False otherwise.
function Is_In_Hidden_Part_In_SPARK (Loc : Source_Ptr) return Boolean;
-- Determine if given location is covered by a hidden region range in the
-- SPARK hides table.
function No_Exception_Handlers_Set return Boolean;
-- Test to see if current restrictions settings specify that no exception
-- handlers are present. This function is called by Gigi when it needs to
-- expand an AT END clean up identifier with no exception handler. True
-- will be returned if the configurable run-time is activated, and either
-- of the restrictions No_Exception_Handlers or No_Exception_Propagation is
-- set. In the latter case, the source may contain handlers but they either
-- get converted using the local goto transformation or deleted.
function No_Exception_Propagation_Active return Boolean;
-- Test to see if current restrictions settings specify that no
-- exception propagation is activated.
function Process_Restriction_Synonyms (N : Node_Id) return Name_Id;
-- Id is a node whose Chars field contains the name of a restriction.
-- If it is one of synonyms that we allow for historical purposes (for
-- list see System.Rident), then the proper official name is returned.
-- Otherwise the Chars field of the argument is returned unchanged.
function Restriction_Active (R : All_Restrictions) return Boolean;
pragma Inline (Restriction_Active);
-- Determines if a given restriction is active. This call should only be
-- used where the compiled code depends on whether the restriction is
-- active. Always use Check_Restriction to record a violation. Note that
-- this returns False if we only have a Restriction_Warnings set, since
-- restriction warnings should never affect generated code. If you want
-- to know if a call to Check_Restriction is needed then use the function
-- Restriction_Check_Required instead.
function Restriction_Check_Required (R : All_Restrictions) return Boolean;
pragma Inline (Restriction_Check_Required);
-- Determines if either a Restriction_Warnings or Restrictions pragma has
-- been given for the specified restriction. If true, then a subsequent
-- call to Check_Restriction is required if the restriction is violated.
-- This must not be used to guard code generation that depends on whether
-- a restriction is active (see Restriction_Active above). Typically it
-- is used to avoid complex code to determine if a restriction is violated,
-- executing this code only if needed.
function Restricted_Profile return Boolean;
-- Tests if set of restrictions corresponding to Profile (Restricted) is
-- currently in effect (set by pragma Profile, or by an appropriate set of
-- individual Restrictions pragmas). Returns True only if all the required
-- restrictions are set.
procedure Set_Hidden_Part_In_SPARK (Loc1, Loc2 : Source_Ptr);
-- Insert a new hidden region range in the SPARK hides table. The effect
-- is to hide any SPARK violation messages which are in the range Loc1 to
-- Loc2-1 (i.e. Loc2 is the first location for reenabling checks).
procedure Set_Profile_Restrictions
(P : Profile_Name;
N : Node_Id;
Warn : Boolean);
-- Sets the set of restrictions associated with the given profile name. N
-- is the node of the construct to which error messages are to be attached
-- as required. Warn is set True for the case of Profile_Warnings where the
-- restrictions are set as warnings rather than legality requirements, and
-- is also True for Profile if the Treat_Restrictions_As_Warnings flag is
-- set. It is false for Profile if this flag is not set.
procedure Set_Restriction
(R : All_Boolean_Restrictions;
N : Node_Id);
-- N is a node (typically a pragma node) that has the effect of setting
-- Boolean restriction R. The restriction is set in Restrictions, and
-- also in Main_Restrictions if this is the main unit.
procedure Set_Restriction
(R : All_Parameter_Restrictions;
N : Node_Id;
V : Integer);
-- Similar to the above, except that this is used for the case of a
-- parameter restriction, and the corresponding value V is given.
procedure Set_Restriction_No_Dependence
(Unit : Node_Id;
Warn : Boolean;
Profile : Profile_Name := No_Profile);
-- Sets given No_Dependence restriction in table if not there already. Warn
-- is True if from Restriction_Warnings, or for Restrictions if the flag
-- Treat_Restrictions_As_Warnings is set. False if from Restrictions and
-- this flag is not set. Profile is set to a non-default value if the
-- No_Dependence restriction comes from a Profile pragma.
procedure Set_Restriction_No_Specification_Of_Aspect
(N : Node_Id;
Warning : Boolean);
-- N is the node id for an identifier from a pragma Restrictions for the
-- No_Specification_Of_Aspect pragma. An error message will be issued if
-- the identifier is not a valid aspect name. Warning is set True for the
-- case of a Restriction_Warnings pragma specifying this restriction and
-- False for a Restrictions pragma specifying this restriction.
procedure Set_Restriction_No_Use_Of_Attribute
(N : Node_Id;
Warning : Boolean);
-- N is the node id for the identifier in a pragma Restrictions for
-- No_Use_Of_Attribute. Caller has verified that this is a valid attribute
-- designator.
procedure Set_Restriction_No_Use_Of_Pragma
(N : Node_Id;
Warning : Boolean);
-- N is the node id for the identifier in a pragma Restrictions for
-- No_Use_Of_Pragma. Caller has verified that this is a valid pragma id.
function Tasking_Allowed return Boolean;
pragma Inline (Tasking_Allowed);
-- Tests if tasking operations are allowed by the current restrictions
-- settings. For tasking to be allowed Max_Tasks must be non-zero.
----------------------------------------------
-- Handling of Boolean Compilation Switches --
----------------------------------------------
-- The following declarations are used for proper saving and restoring of
-- restrictions for separate compilation units. There are two cases:
-- For partition-wide restrictions, we just let the restrictions pragmas
-- pile up, and we never reset them. We might as well detect what we can
-- at compile time. If e.g. a with'ed unit has a restriction for one of
-- the partition-wide restrictions, then the binder will enforce it on
-- all units in the partition, including the unit with the WITH. Although
-- it would not be wrong to leave this till bind time, we might as well
-- flag it earlier at compile time.
-- For non-partition-wide restrictions, we have quite a different state
-- of affairs. Here it would be quite wrong to carry a restriction from
-- a with'ed unit to another with'ed unit, or from a package spec to the
-- package body. This means that we have to reset these non-partition
-- wide restrictions at the start of each separate compilation unit. For
-- units in the extended main program, we need to reset them all to the
-- values set by the configuration pragma file(s). For units not in the
-- extended main program, e.g. with'ed units, we might as well reset all
-- of these restrictions to off (False). The actual initial values will
-- be taken from the config files active when those units are compiled
-- as main units.
type Save_Cunit_Boolean_Restrictions is private;
-- Type used for saving and restoring compilation unit restrictions.
function Cunit_Boolean_Restrictions_Save
return Save_Cunit_Boolean_Restrictions;
-- This function saves the compilation unit restriction settings, leaving
-- then unchanged. This is used e.g. at the start of processing a context
-- clause, so that the main unit restrictions can be restored after all
-- the with'ed units have been processed.
procedure Cunit_Boolean_Restrictions_Restore
(R : Save_Cunit_Boolean_Restrictions);
-- This is the corresponding restore procedure to restore restrictions
-- previously saved by Cunit_Boolean_Restrictions_Save. However it does
-- not reset No_Elaboration_Code, this stays set if it was set before
-- the call, and also if it is set before the call, then the Config
-- setting is also updated to include this restriction. This is what
-- implements the special handling of No_Elaboration_Code.
procedure Save_Config_Cunit_Boolean_Restrictions;
-- This saves the current compilation unit restrictions in an internal
-- variable, and leaves them unchanged. This is called immediately after
-- processing the configuration file pragmas, to record the restrictions
-- set by these configuration file pragmas.
procedure Restore_Config_Cunit_Boolean_Restrictions;
-- This restores the value saved by the previous call to save config values
-- saved by Save_Config_Cunit_Boolean_Restrictions. It is called at the
-- start of processing a new unit that is part of the main sources (e.g.
-- a package spec when the main unit is a package body).
procedure Reset_Cunit_Boolean_Restrictions;
-- Turns off all non-partition-wide boolean restrictions
procedure Add_To_Config_Boolean_Restrictions (R : Restriction_Id);
-- Add specified restriction to stored configuration boolean restrictions.
-- This is used for handling the special case of No_Elaboration_Code.
private
type Save_Cunit_Boolean_Restrictions is
array (Cunit_Boolean_Restrictions) of Boolean;
-- Type used for saving and restoring compilation unit restrictions.
-- See Compilation_Unit_Restrictions_[Save|Restore] subprograms.
end Restrict;
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