1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT 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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 -- This package deals with the implementation of the Restrictions pragma
29 with Namet; use Namet;
30 with Rident; use Rident;
32 with Types; use Types;
33 with Uintp; use Uintp;
37 Restrictions : Restrictions_Info := No_Restrictions;
38 -- This variable records restrictions found in any units in the main
39 -- extended unit, and in the case of restrictions checked for partition
40 -- consistency, restrictions found in any with'ed units, parent specs
41 -- etc, since we may as well check as much as we can at compile time.
42 -- These variables should not be referenced directly by clients. Instead
43 -- use Check_Restrictions to record a violation of a restriction, and
44 -- Restriction_Active to test if a given restriction is active.
46 Restrictions_Loc : array (All_Restrictions) of Source_Ptr :=
47 (others => No_Location);
48 -- Locations of Restrictions pragmas for error message purposes.
49 -- Valid only if corresponding entry in Restrictions is set. A value
50 -- of No_Location is used for implicit restrictions set by another
51 -- pragma, and a value of System_Location is used for restrictions
52 -- set from package Standard by the processing in Targparm.
54 Main_Restrictions : Restrictions_Info := No_Restrictions;
55 -- This variable records only restrictions found in any units of the
56 -- main extended unit. These are the variables used for ali file output,
57 -- since we want the binder to be able to accurately diagnose inter-unit
58 -- restriction violations.
60 Restriction_Warnings : Rident.Restriction_Flags;
61 -- If one of these flags is set, then it means that violation of the
62 -- corresponding restriction results only in a warning message, not
63 -- in an error message, and the restriction is not otherwise enforced.
64 -- Note that the flags in Restrictions are set to indicate that the
65 -- restriction is set in this case, but Main_Restrictions is never
66 -- set if Restriction_Warnings is set, so this does not look like a
67 -- restriction to the binder.
69 type Save_Cunit_Boolean_Restrictions is private;
70 -- Type used for saving and restoring compilation unit restrictions.
71 -- See Cunit_Boolean_Restrictions_[Save|Restore] subprograms.
73 -- The following declarations establish a mapping between restriction
74 -- identifiers, and the names of corresponding restriction library units.
76 type Unit_Entry is record
77 Res_Id : Restriction_Id;
78 Filenm : String (1 .. 8);
81 Unit_Array : constant array (Positive range <>) of Unit_Entry := (
82 (No_Asynchronous_Control, "a-astaco"),
83 (No_Calendar, "a-calend"),
84 (No_Calendar, "calendar"),
85 (No_Delay, "a-calend"),
86 (No_Delay, "calendar"),
87 (No_Dynamic_Priorities, "a-dynpri"),
88 (No_Finalization, "a-finali"),
97 (No_Task_Attributes_Package, "a-tasatt"),
98 (No_Unchecked_Conversion, "a-unccon"),
99 (No_Unchecked_Conversion, "unchconv"),
100 (No_Unchecked_Deallocation, "a-uncdea"),
101 (No_Unchecked_Deallocation, "unchdeal"));
103 -- The following map has True for all GNAT pragmas. It is used to
104 -- implement pragma Restrictions (No_Implementation_Restrictions)
105 -- (which is why this restriction itself is excluded from the list).
107 Implementation_Restriction : array (All_Restrictions) of Boolean :=
108 (Simple_Barriers => True,
110 No_Dispatching_Calls => True,
111 No_Dynamic_Attachment => True,
112 No_Enumeration_Maps => True,
113 No_Entry_Calls_In_Elaboration_Code => True,
114 No_Entry_Queue => True,
115 No_Exception_Handlers => True,
116 No_Exception_Registration => True,
117 No_Implicit_Conditionals => True,
118 No_Implicit_Dynamic_Code => True,
119 No_Implicit_Loops => True,
120 No_Local_Protected_Objects => True,
121 No_Protected_Type_Allocators => True,
122 No_Relative_Delay => True,
123 No_Requeue_Statements => True,
124 No_Secondary_Stack => True,
125 No_Select_Statements => True,
126 No_Standard_Storage_Pools => True,
128 No_Task_Attributes_Package => True,
129 No_Task_Termination => True,
130 No_Wide_Characters => True,
131 Static_Priorities => True,
132 Static_Storage_Size => True,
133 No_Implementation_Attributes => True,
134 No_Implementation_Pragmas => True,
135 No_Elaboration_Code => True,
138 -- The following table records entries made by Restrictions pragmas
139 -- that specify a parameter for No_Dependence. Each such pragma makes
140 -- an entry in this table.
142 -- Note: we have chosen to implement this restriction in the "syntactic"
143 -- form, where we do not check that the named package is a language defined
144 -- package, but instead we allow arbitrary package names. The discussion of
145 -- this issue is not complete in the ARG, but the sense seems to be leaning
146 -- in this direction, which makes more sense to us, since it is much more
147 -- useful, and much easier to implement.
149 type ND_Entry is record
151 -- The unit parameter from the No_Dependence pragma
154 -- True if from Restriction_Warnings, False if from Restrictions
157 package No_Dependence is new Table.Table (
158 Table_Component_Type => ND_Entry,
159 Table_Index_Type => Int,
160 Table_Low_Bound => 0,
161 Table_Initial => 200,
162 Table_Increment => 200,
163 Table_Name => "Name_No_Dependence");
169 function Abort_Allowed return Boolean;
170 pragma Inline (Abort_Allowed);
171 -- Tests to see if abort is allowed by the current restrictions settings.
172 -- For abort to be allowed, either No_Abort_Statements must be False,
173 -- or Max_Asynchronous_Select_Nesting must be non-zero.
175 procedure Check_Restricted_Unit (U : Unit_Name_Type; N : Node_Id);
176 -- Checks if loading of unit U is prohibited by the setting of some
177 -- restriction (e.g. No_IO restricts the loading of unit Ada.Text_IO).
178 -- If a restriction exists post error message at the given node.
180 procedure Check_Restriction
183 V : Uint := Uint_Minus_1);
184 -- Checks that the given restriction is not set, and if it is set, an
185 -- appropriate message is posted on the given node. Also records the
186 -- violation in the appropriate internal arrays. Note that it is
187 -- mandatory to always use this routine to check if a restriction
188 -- is violated. Such checks must never be done directly by the caller,
189 -- since otherwise violations in the absence of restrictions are not
190 -- properly recorded. The value of V is relevant only for parameter
191 -- restrictions, and in this case indicates the exact count for the
192 -- violation. If the exact count is not known, V is left at its
193 -- default value of -1 which indicates an unknown count.
195 procedure Check_Restriction_No_Dependence (U : Node_Id; Err : Node_Id);
196 -- Called when a dependence on a unit is created (either implicitly, or by
197 -- an explicit WITH clause). U is a node for the unit involved, and Err
198 -- is the node to which an error will be attached if necessary.
200 procedure Check_Elaboration_Code_Allowed (N : Node_Id);
201 -- Tests to see if elaboration code is allowed by the current restrictions
202 -- settings. This function is called by Gigi when it needs to define
203 -- an elaboration routine. If elaboration code is not allowed, an error
204 -- message is posted on the node given as argument.
206 procedure Check_No_Implicit_Heap_Alloc (N : Node_Id);
207 -- Equivalent to Check_Restriction (No_Implicit_Heap_Allocations, N).
208 -- Provided for easy use by back end, which has to check this restriction.
210 function Cunit_Boolean_Restrictions_Save
211 return Save_Cunit_Boolean_Restrictions;
212 -- This function saves the compilation unit restriction settings, and
213 -- resets them to False. This is used e.g. when compiling a with'ed
214 -- unit to avoid incorrectly propagating restrictions. Note that it
215 -- would not be wrong to also save and reset the partition restrictions,
216 -- since the binder would catch inconsistencies, but actually it is a
217 -- good thing to acquire restrictions from with'ed units if they are
218 -- required to be partition wide, because it allows the restriction
219 -- violation message to be given at compile time instead of link time.
221 procedure Cunit_Boolean_Restrictions_Restore
222 (R : Save_Cunit_Boolean_Restrictions);
223 -- This is the corresponding restore procedure to restore restrictions
224 -- previously saved by Cunit_Boolean_Restrictions_Save.
226 function Get_Restriction_Id
227 (N : Name_Id) return Restriction_Id;
228 -- Given an identifier name, determines if it is a valid restriction
229 -- identifier, and if so returns the corresponding Restriction_Id
230 -- value, otherwise returns Not_A_Restriction_Id.
232 function No_Exception_Handlers_Set return Boolean;
233 -- Test to see if current restrictions settings specify that no exception
234 -- handlers are present. This function is called by Gigi when it needs to
235 -- expand an AT END clean up identifier with no exception handler. True
236 -- will be returned if the configurable run-time is activated, and either
237 -- of the restrictions No_Exception_Handlers or No_Exception_Propagation is
238 -- set. In the latter case, the source may contain handlers but they either
239 -- get converted using the local goto transformation or deleted.
241 function Process_Restriction_Synonyms (N : Node_Id) return Name_Id;
242 -- Id is a node whose Chars field contains the name of a restriction.
243 -- If it is one of synonyms that we allow for historical purposes (for
244 -- list see System.Rident), then the proper official name is returned.
245 -- Otherwise the Chars field of the argument is returned unchanged.
247 function Restriction_Active (R : All_Restrictions) return Boolean;
248 pragma Inline (Restriction_Active);
249 -- Determines if a given restriction is active. This call should only be
250 -- used where the compiled code depends on whether the restriction is
251 -- active. Always use Check_Restriction to record a violation. Note that
252 -- this returns False if we only have a Restriction_Warnings set, since
253 -- restriction warnings should never affect generated code.
255 function Restricted_Profile return Boolean;
256 -- Tests if set of restrictions corresponding to Profile (Restricted) is
257 -- currently in effect (set by pragma Profile, or by an appropriate set
258 -- of individual Restrictions pragms). Returns True only if all the
259 -- required restrictions are set.
261 procedure Set_Profile_Restrictions
265 -- Sets the set of restrictions associated with the given profile
266 -- name. N is the node of the construct to which error messages
267 -- are to be attached as required. Warn is set True for the case
268 -- of Profile_Warnings where the restrictions are set as warnings
269 -- rather than legality requirements.
271 procedure Set_Restriction
272 (R : All_Boolean_Restrictions;
274 -- N is a node (typically a pragma node) that has the effect of setting
275 -- Boolean restriction R. The restriction is set in Restrictions, and
276 -- also in Main_Restrictions if this is the main unit.
278 procedure Set_Restriction
279 (R : All_Parameter_Restrictions;
282 -- Similar to the above, except that this is used for the case of a
283 -- parameter restriction, and the corresponding value V is given.
285 procedure Set_Restriction_No_Dependence
288 -- Sets given No_Dependence restriction in table if not there already.
289 -- Warn is True if from Restriction_Warnings, False if from Restrictions.
291 function Tasking_Allowed return Boolean;
292 pragma Inline (Tasking_Allowed);
293 -- Tests to see if tasking operations are allowed by the current
294 -- restrictions settings. For tasking to be allowed Max_Tasks must
298 type Save_Cunit_Boolean_Restrictions is
299 array (Cunit_Boolean_Restrictions) of Boolean;
300 -- Type used for saving and restoring compilation unit restrictions.
301 -- See Compilation_Unit_Restrictions_[Save|Restore] subprograms.
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