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 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. 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 COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 -- This package deals with the implementation of the Restrictions pragma
28 with Namet; use Namet;
29 with Rident; use Rident;
31 with Types; use Types;
32 with Uintp; use Uintp;
36 Restrictions : Restrictions_Info := No_Restrictions;
37 -- This variable records restrictions found in any units in the main
38 -- extended unit, and in the case of restrictions checked for partition
39 -- consistency, restrictions found in any with'ed units, parent specs
40 -- etc, since we may as well check as much as we can at compile time.
41 -- These variables should not be referenced directly by clients. Instead
42 -- use Check_Restrictions to record a violation of a restriction, and
43 -- Restriction_Active to test if a given restriction is active.
45 Restrictions_Loc : array (All_Restrictions) of Source_Ptr :=
46 (others => No_Location);
47 -- Locations of Restrictions pragmas for error message purposes.
48 -- Valid only if corresponding entry in Restrictions is set. A value
49 -- of No_Location is used for implicit restrictions set by another
50 -- pragma, and a value of System_Location is used for restrictions
51 -- set from package Standard by the processing in Targparm.
53 Main_Restrictions : Restrictions_Info := No_Restrictions;
54 -- This variable records only restrictions found in any units of the
55 -- main extended unit. These are the variables used for ali file output,
56 -- since we want the binder to be able to accurately diagnose inter-unit
57 -- restriction violations.
59 Restriction_Warnings : Rident.Restriction_Flags;
60 -- If one of these flags is set, then it means that violation of the
61 -- corresponding restriction results only in a warning message, not
62 -- in an error message, and the restriction is not otherwise enforced.
63 -- Note that the flags in Restrictions are set to indicate that the
64 -- restriction is set in this case, but Main_Restrictions is never
65 -- set if Restriction_Warnings is set, so this does not look like a
66 -- restriction to the binder.
68 type Save_Cunit_Boolean_Restrictions is private;
69 -- Type used for saving and restoring compilation unit restrictions.
70 -- See Cunit_Boolean_Restrictions_[Save|Restore] subprograms.
72 -- The following declarations establish a mapping between restriction
73 -- identifiers, and the names of corresponding restriction library units.
75 type Unit_Entry is record
76 Res_Id : Restriction_Id;
77 Filenm : String (1 .. 8);
80 Unit_Array : constant array (Positive range <>) of Unit_Entry := (
81 (No_Asynchronous_Control, "a-astaco"),
82 (No_Calendar, "a-calend"),
83 (No_Calendar, "calendar"),
84 (No_Delay, "a-calend"),
85 (No_Delay, "calendar"),
86 (No_Dynamic_Priorities, "a-dynpri"),
87 (No_Finalization, "a-finali"),
96 (No_Task_Attributes_Package, "a-tasatt"),
97 (No_Unchecked_Conversion, "a-unccon"),
98 (No_Unchecked_Conversion, "unchconv"),
99 (No_Unchecked_Deallocation, "a-uncdea"),
100 (No_Unchecked_Deallocation, "unchdeal"));
102 -- The following map has True for all GNAT pragmas. It is used to
103 -- implement pragma Restrictions (No_Implementation_Restrictions)
104 -- (which is why this restriction itself is excluded from the list).
106 Implementation_Restriction : array (All_Restrictions) of Boolean :=
107 (Simple_Barriers => True,
109 No_Dispatching_Calls => True,
110 No_Dynamic_Attachment => True,
111 No_Enumeration_Maps => True,
112 No_Entry_Calls_In_Elaboration_Code => True,
113 No_Entry_Queue => True,
114 No_Exception_Handlers => True,
115 No_Exception_Registration => True,
116 No_Implicit_Conditionals => True,
117 No_Implicit_Dynamic_Code => True,
118 No_Implicit_Loops => True,
119 No_Local_Protected_Objects => True,
120 No_Protected_Type_Allocators => True,
121 No_Relative_Delay => True,
122 No_Requeue_Statements => True,
123 No_Secondary_Stack => True,
124 No_Select_Statements => True,
125 No_Standard_Storage_Pools => True,
127 No_Task_Attributes_Package => True,
128 No_Task_Termination => True,
129 No_Wide_Characters => True,
130 Static_Priorities => True,
131 Static_Storage_Size => True,
132 No_Implementation_Attributes => True,
133 No_Implementation_Pragmas => True,
134 No_Elaboration_Code => True,
137 -- The following table records entries made by Restrictions pragmas
138 -- that specify a parameter for No_Dependence. Each such pragma makes
139 -- an entry in this table.
141 -- Note: we have chosen to implement this restriction in the "syntactic"
142 -- form, where we do not check that the named package is a language defined
143 -- package, but instead we allow arbitrary package names. The discussion of
144 -- this issue is not complete in the ARG, but the sense seems to be leaning
145 -- in this direction, which makes more sense to us, since it is much more
146 -- useful, and much easier to implement.
148 type ND_Entry is record
150 -- The unit parameter from the No_Dependence pragma
153 -- True if from Restriction_Warnings, False if from Restrictions
156 package No_Dependence is new Table.Table (
157 Table_Component_Type => ND_Entry,
158 Table_Index_Type => Int,
159 Table_Low_Bound => 0,
160 Table_Initial => 200,
161 Table_Increment => 200,
162 Table_Name => "Name_No_Dependence");
168 function Abort_Allowed return Boolean;
169 pragma Inline (Abort_Allowed);
170 -- Tests to see if abort is allowed by the current restrictions settings.
171 -- For abort to be allowed, either No_Abort_Statements must be False,
172 -- or Max_Asynchronous_Select_Nesting must be non-zero.
174 procedure Check_Compiler_Unit (N : Node_Id);
175 -- If unit N is in a unit that has a pragma Compiler_Unit, then a message
176 -- is posted on node N noting use of a construct that is not permitted in
179 procedure Check_Restricted_Unit (U : Unit_Name_Type; N : Node_Id);
180 -- Checks if loading of unit U is prohibited by the setting of some
181 -- restriction (e.g. No_IO restricts the loading of unit Ada.Text_IO).
182 -- If a restriction exists post error message at the given node.
184 procedure Check_Restriction
187 V : Uint := Uint_Minus_1);
188 -- Checks that the given restriction is not set, and if it is set, an
189 -- appropriate message is posted on the given node. Also records the
190 -- violation in the appropriate internal arrays. Note that it is
191 -- mandatory to always use this routine to check if a restriction
192 -- is violated. Such checks must never be done directly by the caller,
193 -- since otherwise violations in the absence of restrictions are not
194 -- properly recorded. The value of V is relevant only for parameter
195 -- restrictions, and in this case indicates the exact count for the
196 -- violation. If the exact count is not known, V is left at its
197 -- default value of -1 which indicates an unknown count.
199 procedure Check_Restriction_No_Dependence (U : Node_Id; Err : Node_Id);
200 -- Called when a dependence on a unit is created (either implicitly, or by
201 -- an explicit WITH clause). U is a node for the unit involved, and Err
202 -- is the node to which an error will be attached if necessary.
204 procedure Check_Elaboration_Code_Allowed (N : Node_Id);
205 -- Tests to see if elaboration code is allowed by the current restrictions
206 -- settings. This function is called by Gigi when it needs to define
207 -- an elaboration routine. If elaboration code is not allowed, an error
208 -- message is posted on the node given as argument.
210 procedure Check_No_Implicit_Heap_Alloc (N : Node_Id);
211 -- Equivalent to Check_Restriction (No_Implicit_Heap_Allocations, N).
212 -- Provided for easy use by back end, which has to check this restriction.
214 function Cunit_Boolean_Restrictions_Save
215 return Save_Cunit_Boolean_Restrictions;
216 -- This function saves the compilation unit restriction settings, and
217 -- resets them to False. This is used e.g. when compiling a with'ed
218 -- unit to avoid incorrectly propagating restrictions. Note that it
219 -- would not be wrong to also save and reset the partition restrictions,
220 -- since the binder would catch inconsistencies, but actually it is a
221 -- good thing to acquire restrictions from with'ed units if they are
222 -- required to be partition wide, because it allows the restriction
223 -- violation message to be given at compile time instead of link time.
225 procedure Cunit_Boolean_Restrictions_Restore
226 (R : Save_Cunit_Boolean_Restrictions);
227 -- This is the corresponding restore procedure to restore restrictions
228 -- previously saved by Cunit_Boolean_Restrictions_Save.
230 function Get_Restriction_Id
231 (N : Name_Id) return Restriction_Id;
232 -- Given an identifier name, determines if it is a valid restriction
233 -- identifier, and if so returns the corresponding Restriction_Id
234 -- value, otherwise returns Not_A_Restriction_Id.
236 function No_Exception_Handlers_Set return Boolean;
237 -- Test to see if current restrictions settings specify that no exception
238 -- handlers are present. This function is called by Gigi when it needs to
239 -- expand an AT END clean up identifier with no exception handler. True
240 -- will be returned if the configurable run-time is activated, and either
241 -- of the restrictions No_Exception_Handlers or No_Exception_Propagation is
242 -- set. In the latter case, the source may contain handlers but they either
243 -- get converted using the local goto transformation or deleted.
245 function Process_Restriction_Synonyms (N : Node_Id) return Name_Id;
246 -- Id is a node whose Chars field contains the name of a restriction.
247 -- If it is one of synonyms that we allow for historical purposes (for
248 -- list see System.Rident), then the proper official name is returned.
249 -- Otherwise the Chars field of the argument is returned unchanged.
251 function Restriction_Active (R : All_Restrictions) return Boolean;
252 pragma Inline (Restriction_Active);
253 -- Determines if a given restriction is active. This call should only be
254 -- used where the compiled code depends on whether the restriction is
255 -- active. Always use Check_Restriction to record a violation. Note that
256 -- this returns False if we only have a Restriction_Warnings set, since
257 -- restriction warnings should never affect generated code.
259 function Restricted_Profile return Boolean;
260 -- Tests if set of restrictions corresponding to Profile (Restricted) is
261 -- currently in effect (set by pragma Profile, or by an appropriate set
262 -- of individual Restrictions pragms). Returns True only if all the
263 -- required restrictions are set.
265 procedure Set_Profile_Restrictions
269 -- Sets the set of restrictions associated with the given profile
270 -- name. N is the node of the construct to which error messages
271 -- are to be attached as required. Warn is set True for the case
272 -- of Profile_Warnings where the restrictions are set as warnings
273 -- rather than legality requirements.
275 procedure Set_Restriction
276 (R : All_Boolean_Restrictions;
278 -- N is a node (typically a pragma node) that has the effect of setting
279 -- Boolean restriction R. The restriction is set in Restrictions, and
280 -- also in Main_Restrictions if this is the main unit.
282 procedure Set_Restriction
283 (R : All_Parameter_Restrictions;
286 -- Similar to the above, except that this is used for the case of a
287 -- parameter restriction, and the corresponding value V is given.
289 procedure Set_Restriction_No_Dependence
292 -- Sets given No_Dependence restriction in table if not there already.
293 -- Warn is True if from Restriction_Warnings, False if from Restrictions.
295 function Tasking_Allowed return Boolean;
296 pragma Inline (Tasking_Allowed);
297 -- Tests to see if tasking operations are allowed by the current
298 -- restrictions settings. For tasking to be allowed Max_Tasks must
302 type Save_Cunit_Boolean_Restrictions is
303 array (Cunit_Boolean_Restrictions) of Boolean;
304 -- Type used for saving and restoring compilation unit restrictions.
305 -- See Compilation_Unit_Restrictions_[Save|Restore] subprograms.
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