1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2008, 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 Restriction_Profile_Name : array (All_Restrictions) of Profile_Name;
54 -- Entries in this array are valid only if the corresponding restriction
55 -- in Restrictions set. The value is the corresponding profile name if the
56 -- restriction was set by a Profile or Profile_Warnings pragma. The value
57 -- is No_Profile in all other cases.
59 Main_Restrictions : Restrictions_Info := No_Restrictions;
60 -- This variable records only restrictions found in any units of the
61 -- main extended unit. These are the variables used for ali file output,
62 -- since we want the binder to be able to accurately diagnose inter-unit
63 -- restriction violations.
65 Restriction_Warnings : Rident.Restriction_Flags;
66 -- If one of these flags is set, then it means that violation of the
67 -- corresponding restriction results only in a warning message, not
68 -- in an error message, and the restriction is not otherwise enforced.
69 -- Note that the flags in Restrictions are set to indicate that the
70 -- restriction is set in this case, but Main_Restrictions is never
71 -- set if Restriction_Warnings is set, so this does not look like a
72 -- restriction to the binder.
74 type Save_Cunit_Boolean_Restrictions is private;
75 -- Type used for saving and restoring compilation unit restrictions.
76 -- See Cunit_Boolean_Restrictions_[Save|Restore] subprograms.
78 -- The following declarations establish a mapping between restriction
79 -- identifiers, and the names of corresponding restriction library units.
81 type Unit_Entry is record
82 Res_Id : Restriction_Id;
83 Filenm : String (1 .. 8);
86 Unit_Array : constant array (Positive range <>) of Unit_Entry := (
87 (No_Asynchronous_Control, "a-astaco"),
88 (No_Calendar, "a-calend"),
89 (No_Calendar, "calendar"),
90 (No_Delay, "a-calend"),
91 (No_Delay, "calendar"),
92 (No_Dynamic_Priorities, "a-dynpri"),
93 (No_Finalization, "a-finali"),
102 (No_Task_Attributes_Package, "a-tasatt"),
103 (No_Unchecked_Conversion, "a-unccon"),
104 (No_Unchecked_Conversion, "unchconv"),
105 (No_Unchecked_Deallocation, "a-uncdea"),
106 (No_Unchecked_Deallocation, "unchdeal"));
108 -- The following map has True for all GNAT pragmas. It is used to
109 -- implement pragma Restrictions (No_Implementation_Restrictions)
110 -- (which is why this restriction itself is excluded from the list).
112 Implementation_Restriction : array (All_Restrictions) of Boolean :=
113 (Simple_Barriers => True,
114 No_Asynchronous_Control => True,
116 No_Dispatching_Calls => True,
117 No_Dynamic_Attachment => True,
118 No_Elaboration_Code => True,
119 No_Enumeration_Maps => True,
120 No_Entry_Calls_In_Elaboration_Code => True,
121 No_Entry_Queue => True,
122 No_Exception_Handlers => True,
123 No_Exception_Registration => True,
124 No_Implementation_Attributes => True,
125 No_Implementation_Pragmas => True,
126 No_Implicit_Conditionals => True,
127 No_Implicit_Dynamic_Code => True,
128 No_Implicit_Loops => True,
129 No_Local_Protected_Objects => True,
130 No_Protected_Type_Allocators => True,
131 No_Relative_Delay => True,
132 No_Requeue_Statements => True,
133 No_Secondary_Stack => True,
134 No_Select_Statements => True,
135 No_Standard_Storage_Pools => True,
137 No_Task_Attributes_Package => True,
138 No_Task_Termination => True,
139 No_Unchecked_Conversion => True,
140 No_Unchecked_Deallocation => True,
141 No_Wide_Characters => True,
142 Static_Priorities => True,
143 Static_Storage_Size => True,
146 -- The following table records entries made by Restrictions pragmas
147 -- that specify a parameter for No_Dependence. Each such pragma makes
148 -- an entry in this table.
150 -- Note: we have chosen to implement this restriction in the "syntactic"
151 -- form, where we do not check that the named package is a language defined
152 -- package, but instead we allow arbitrary package names. The discussion of
153 -- this issue is not complete in the ARG, but the sense seems to be leaning
154 -- in this direction, which makes more sense to us, since it is much more
155 -- useful, and much easier to implement.
157 type ND_Entry is record
159 -- The unit parameter from the No_Dependence pragma
162 -- True if from Restriction_Warnings, False if from Restrictions
164 Profile : Profile_Name;
165 -- Set to name of profile from which No_Dependence entry came, or to
166 -- No_Profile if a pragma Restriction set the No_Dependence entry.
169 package No_Dependence is new Table.Table (
170 Table_Component_Type => ND_Entry,
171 Table_Index_Type => Int,
172 Table_Low_Bound => 0,
173 Table_Initial => 200,
174 Table_Increment => 200,
175 Table_Name => "Name_No_Dependence");
181 function Abort_Allowed return Boolean;
182 pragma Inline (Abort_Allowed);
183 -- Tests to see if abort is allowed by the current restrictions settings.
184 -- For abort to be allowed, either No_Abort_Statements must be False,
185 -- or Max_Asynchronous_Select_Nesting must be non-zero.
187 procedure Check_Compiler_Unit (N : Node_Id);
188 -- If unit N is in a unit that has a pragma Compiler_Unit, then a message
189 -- is posted on node N noting use of a construct that is not permitted in
192 procedure Check_Restricted_Unit (U : Unit_Name_Type; N : Node_Id);
193 -- Checks if loading of unit U is prohibited by the setting of some
194 -- restriction (e.g. No_IO restricts the loading of unit Ada.Text_IO).
195 -- If a restriction exists post error message at the given node.
197 procedure Check_Restriction
200 V : Uint := Uint_Minus_1);
201 -- Checks that the given restriction is not set, and if it is set, an
202 -- appropriate message is posted on the given node. Also records the
203 -- violation in the appropriate internal arrays. Note that it is mandatory
204 -- to always use this routine to check if a restriction is violated. Such
205 -- checks must never be done directly by the caller, since otherwise
206 -- violations in the absence of restrictions are not properly recorded. The
207 -- value of V is relevant only for parameter restrictions, and in this case
208 -- indicates the exact count for the violation. If the exact count is not
209 -- known, V is left at its default of -1 which indicates an unknown count.
211 procedure Check_Restriction_No_Dependence (U : Node_Id; Err : Node_Id);
212 -- Called when a dependence on a unit is created (either implicitly, or by
213 -- an explicit WITH clause). U is a node for the unit involved, and Err
214 -- is the node to which an error will be attached if necessary.
216 procedure Check_Elaboration_Code_Allowed (N : Node_Id);
217 -- Tests to see if elaboration code is allowed by the current restrictions
218 -- settings. This function is called by Gigi when it needs to define
219 -- an elaboration routine. If elaboration code is not allowed, an error
220 -- message is posted on the node given as argument.
222 procedure Check_Implicit_Dynamic_Code_Allowed (N : Node_Id);
223 -- Tests to see if dynamic code generation (dynamically generated
224 -- trampolines, in particular) is allowed by the current restrictions
225 -- settings. This function is called by Gigi when it needs to generate code
226 -- that generates a trampoline. If not allowed, an error message is posted
227 -- on the node given as argument.
229 procedure Check_No_Implicit_Heap_Alloc (N : Node_Id);
230 -- Equivalent to Check_Restriction (No_Implicit_Heap_Allocations, N).
231 -- Provided for easy use by back end, which has to check this restriction.
233 function Cunit_Boolean_Restrictions_Save
234 return Save_Cunit_Boolean_Restrictions;
235 -- This function saves the compilation unit restriction settings, and
236 -- resets them to False. This is used e.g. when compiling a with'ed
237 -- unit to avoid incorrectly propagating restrictions. Note that it
238 -- would not be wrong to also save and reset the partition restrictions,
239 -- since the binder would catch inconsistencies, but actually it is a
240 -- good thing to acquire restrictions from with'ed units if they are
241 -- required to be partition wide, because it allows the restriction
242 -- violation message to be given at compile time instead of link time.
244 procedure Cunit_Boolean_Restrictions_Restore
245 (R : Save_Cunit_Boolean_Restrictions);
246 -- This is the corresponding restore procedure to restore restrictions
247 -- previously saved by Cunit_Boolean_Restrictions_Save.
249 function Get_Restriction_Id
250 (N : Name_Id) return Restriction_Id;
251 -- Given an identifier name, determines if it is a valid restriction
252 -- identifier, and if so returns the corresponding Restriction_Id
253 -- value, otherwise returns Not_A_Restriction_Id.
255 function No_Exception_Handlers_Set return Boolean;
256 -- Test to see if current restrictions settings specify that no exception
257 -- handlers are present. This function is called by Gigi when it needs to
258 -- expand an AT END clean up identifier with no exception handler. True
259 -- will be returned if the configurable run-time is activated, and either
260 -- of the restrictions No_Exception_Handlers or No_Exception_Propagation is
261 -- set. In the latter case, the source may contain handlers but they either
262 -- get converted using the local goto transformation or deleted.
264 function No_Exception_Propagation_Active return Boolean;
265 -- Test to see if current restrictions settings specify that no
266 -- exception propagation is activated.
268 function Process_Restriction_Synonyms (N : Node_Id) return Name_Id;
269 -- Id is a node whose Chars field contains the name of a restriction.
270 -- If it is one of synonyms that we allow for historical purposes (for
271 -- list see System.Rident), then the proper official name is returned.
272 -- Otherwise the Chars field of the argument is returned unchanged.
274 function Restriction_Active (R : All_Restrictions) return Boolean;
275 pragma Inline (Restriction_Active);
276 -- Determines if a given restriction is active. This call should only be
277 -- used where the compiled code depends on whether the restriction is
278 -- active. Always use Check_Restriction to record a violation. Note that
279 -- this returns False if we only have a Restriction_Warnings set, since
280 -- restriction warnings should never affect generated code.
282 function Restricted_Profile return Boolean;
283 -- Tests if set of restrictions corresponding to Profile (Restricted) is
284 -- currently in effect (set by pragma Profile, or by an appropriate set
285 -- of individual Restrictions pragmas). Returns True only if all the
286 -- required restrictions are set.
288 procedure Set_Profile_Restrictions
292 -- Sets the set of restrictions associated with the given profile name. N
293 -- is the node of the construct to which error messages are to be attached
294 -- as required. Warn is set True for the case of Profile_Warnings where the
295 -- restrictions are set as warnings rather than legality requirements, and
296 -- is also True for Profile if the Treat_Restrictions_As_Warnings flag is
297 -- set. It is false for Profile if this flag is not set.
299 procedure Set_Restriction
300 (R : All_Boolean_Restrictions;
302 -- N is a node (typically a pragma node) that has the effect of setting
303 -- Boolean restriction R. The restriction is set in Restrictions, and
304 -- also in Main_Restrictions if this is the main unit.
306 procedure Set_Restriction
307 (R : All_Parameter_Restrictions;
310 -- Similar to the above, except that this is used for the case of a
311 -- parameter restriction, and the corresponding value V is given.
313 procedure Set_Restriction_No_Dependence
316 Profile : Profile_Name := No_Profile);
317 -- Sets given No_Dependence restriction in table if not there already.
318 -- Warn is True if from Restriction_Warnings, or for Restrictions if flag
319 -- Treat_Restrictions_As_Warnings is set. False if from Restrictions and
320 -- this flag is not set. Profile is set to a non-default value if the
321 -- No_Dependence restriction comes from a Profile pragma.
323 function Tasking_Allowed return Boolean;
324 pragma Inline (Tasking_Allowed);
325 -- Tests if tasking operations are allowed by the current restrictions
326 -- settings. For tasking to be allowed Max_Tasks must be non-zero.
329 type Save_Cunit_Boolean_Restrictions is
330 array (Cunit_Boolean_Restrictions) of Boolean;
331 -- Type used for saving and restoring compilation unit restrictions.
332 -- See Compilation_Unit_Restrictions_[Save|Restore] subprograms.
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