1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- R E S T R I C T -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2003 Free Software Foundation, Inc. -- 10-- -- 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, 59 Temple Place - Suite 330, Boston, -- 20-- MA 02111-1307, USA. -- 21-- -- 22-- GNAT was originally developed by the GNAT team at New York University. -- 23-- Extensive contributions were provided by Ada Core Technologies Inc. -- 24-- -- 25------------------------------------------------------------------------------ 26 27-- This package deals with the implementation of the Restrictions pragma 28 29with Rident; 30with Types; use Types; 31with Uintp; use Uintp; 32 33package Restrict is 34 35 type Restriction_Id is new Rident.Restriction_Id; 36 -- The type Restriction_Id defines the set of restriction identifiers, 37 -- which take no parameter (i.e. they are either present or not present). 38 -- The actual definition is in the separate package Rident, so that 39 -- it can easily be accessed by the binder without dragging in lots 40 -- of stuff. 41 42 subtype All_Restrictions is 43 Restriction_Id range 44 Restriction_Id (Rident.All_Restrictions'First) .. 45 Restriction_Id (Rident.All_Restrictions'Last); 46 -- All restriction identifiers 47 48 subtype Partition_Restrictions is 49 Restriction_Id range 50 Restriction_Id (Rident.Partition_Restrictions'First) .. 51 Restriction_Id (Rident.Partition_Restrictions'Last); 52 -- Range of restriction identifiers that are checked by the binder 53 54 subtype Compilation_Unit_Restrictions is 55 Restriction_Id range 56 Restriction_Id (Rident.Compilation_Unit_Restrictions'First) .. 57 Restriction_Id (Rident.Compilation_Unit_Restrictions'Last); 58 -- Range of restriction identifiers not checked by binder 59 60 type Restriction_Parameter_Id is new Rident.Restriction_Parameter_Id; 61 -- The type Restriction_Parameter_Id records cases where a parameter is 62 -- present in the corresponding pragma. The actual definition is in the 63 -- separate package Rident for consistency. 64 65 type Restrictions_Flags is array (Restriction_Id) of Boolean; 66 -- Type used for arrays indexed by Restriction_Id. 67 68 Restrictions : Restrictions_Flags := (others => False); 69 -- Corresponding entry is False if restriction is not active, and 70 -- True if the restriction is active, i.e. if a pragma Restrictions 71 -- has been seen anywhere. Note that we are happy to pick up any 72 -- restrictions pragmas in with'ed units, since we are required to 73 -- be consistent at link time, and we might as well find the error 74 -- at compile time. Clients must NOT use this array for checking to 75 -- see if a restriction is violated, instead it is required that the 76 -- Check_Restriction subprograms be used for this purpose. The only 77 -- legitimate direct use of this array is when the code is modified 78 -- as a result of the restriction in some way. 79 80 Restrictions_Loc : array (Restriction_Id) of Source_Ptr := 81 (others => No_Location); 82 -- Locations of Restrictions pragmas for error message purposes. 83 -- Valid only if corresponding entry in Restrictions is set. A value 84 -- of No_Location is used for implicit restrictions set by another 85 -- pragma, and a value of System_Location is used for restrictions 86 -- set from package Standard by the processing in Targparm. 87 88 Main_Restrictions : Restrictions_Flags := (others => False); 89 -- This variable saves the cumulative restrictions in effect compiling 90 -- any unit that is part of the extended main unit (i.e. the compiled 91 -- unit, its spec if any, and its subunits if any). The reason we keep 92 -- track of this is for the information that goes to the binder about 93 -- restrictions that are set. The binder will identify a unit that has 94 -- a restrictions pragma for error message purposes, and we do not want 95 -- to pick up a restrictions pragma in a with'ed unit for this purpose. 96 97 Violations : Restrictions_Flags := (others => False); 98 -- Corresponding entry is False if the restriction has not been 99 -- violated in the current main unit, and True if it has been violated. 100 101 Restriction_Warnings : Restrictions_Flags := (others => False); 102 -- If one of these flags is set, then it means that violation of the 103 -- corresponding restriction results only in a warning message, not 104 -- in an error message, and the restriction is not otherwise enforced. 105 106 Restriction_Parameters : 107 array (Restriction_Parameter_Id) of Uint := (others => No_Uint); 108 -- This array indicates the setting of restriction parameter identifier 109 -- values. All values are initially set to No_Uint indicating that the 110 -- parameter is not set, and are set to the appropriate non-negative 111 -- value if a Restrictions pragma specifies the corresponding 112 -- restriction parameter identifier with an appropriate value. 113 114 Restriction_Parameters_Loc : 115 array (Restriction_Parameter_Id) of Source_Ptr; 116 -- Locations of Restrictions pragmas for error message purposes. 117 -- Valid only if corresponding entry in Restriction_Parameters is 118 -- set to a value other than No_Uint. 119 120 type Unit_Entry is record 121 Res_Id : Restriction_Id; 122 Filenm : String (1 .. 8); 123 end record; 124 125 type Unit_Array_Type is array (Positive range <>) of Unit_Entry; 126 127 Unit_Array : constant Unit_Array_Type := ( 128 (No_Asynchronous_Control, "a-astaco"), 129 (No_Calendar, "a-calend"), 130 (No_Calendar, "calendar"), 131 (No_Delay, "a-calend"), 132 (No_Delay, "calendar"), 133 (No_Dynamic_Priorities, "a-dynpri"), 134 (No_Finalization, "a-finali"), 135 (No_IO, "a-direio"), 136 (No_IO, "directio"), 137 (No_IO, "a-sequio"), 138 (No_IO, "sequenio"), 139 (No_IO, "a-ststio"), 140 (No_IO, "a-textio"), 141 (No_IO, "text_io "), 142 (No_IO, "a-witeio"), 143 (No_Task_Attributes, "a-tasatt"), 144 (No_Streams, "a-stream"), 145 (No_Unchecked_Conversion, "a-unccon"), 146 (No_Unchecked_Conversion, "unchconv"), 147 (No_Unchecked_Deallocation, "a-uncdea"), 148 (No_Unchecked_Deallocation, "unchdeal")); 149 -- This array defines the mapping between restriction identifiers and 150 -- predefined language files containing units for which the identifier 151 -- forbids semantic dependence. 152 153 type Save_Compilation_Unit_Restrictions is private; 154 -- Type used for saving and restoring compilation unit restrictions. 155 -- See Compilation_Unit_Restrictions_[Save|Restore] subprograms. 156 157 -- The following map has True for all GNAT pragmas. It is used to 158 -- implement pragma Restrictions (No_Implementation_Restrictions) 159 -- (which is why this restriction itself is excluded from the list). 160 161 Implementation_Restriction : Restrictions_Flags := 162 (Boolean_Entry_Barriers => True, 163 No_Calendar => True, 164 No_Dynamic_Interrupts => True, 165 No_Enumeration_Maps => True, 166 No_Entry_Calls_In_Elaboration_Code => True, 167 No_Entry_Queue => True, 168 No_Exception_Handlers => True, 169 No_Exception_Registration => True, 170 No_Implicit_Conditionals => True, 171 No_Implicit_Dynamic_Code => True, 172 No_Implicit_Loops => True, 173 No_Local_Protected_Objects => True, 174 No_Protected_Type_Allocators => True, 175 No_Relative_Delay => True, 176 No_Requeue => True, 177 No_Secondary_Stack => True, 178 No_Select_Statements => True, 179 No_Standard_Storage_Pools => True, 180 No_Streams => True, 181 No_Task_Attributes => True, 182 No_Task_Termination => True, 183 No_Wide_Characters => True, 184 Static_Priorities => True, 185 Static_Storage_Size => True, 186 No_Implementation_Attributes => True, 187 No_Implementation_Pragmas => True, 188 No_Elaboration_Code => True, 189 others => False); 190 191 ----------------- 192 -- Subprograms -- 193 ----------------- 194 195 function Abort_Allowed return Boolean; 196 pragma Inline (Abort_Allowed); 197 -- Tests to see if abort is allowed by the current restrictions settings. 198 -- For abort to be allowed, either No_Abort_Statements must be False, 199 -- or Max_Asynchronous_Select_Nesting must be non-zero. 200 201 procedure Check_Restricted_Unit (U : Unit_Name_Type; N : Node_Id); 202 -- Checks if loading of unit U is prohibited by the setting of some 203 -- restriction (e.g. No_IO restricts the loading of unit Ada.Text_IO). 204 -- If a restriction exists post error message at the given node. 205 206 procedure Check_Restriction (R : Restriction_Id; N : Node_Id); 207 -- Checks that the given restriction is not set, and if it is set, an 208 -- appropriate message is posted on the given node. Also records the 209 -- violation in the violations array. Note that it is mandatory to 210 -- always use this routine to check if a restriction is violated. Such 211 -- checks must never be done directly by the caller, since otherwise 212 -- they are not properly recorded in the violations array. 213 214 procedure Check_Restriction 215 (R : Restriction_Parameter_Id; 216 V : Uint; 217 N : Node_Id); 218 -- Checks that the count in V does not exceed the maximum value of the 219 -- restriction parameter value corresponding to the given restriction 220 -- parameter identifier (if it has been set). If the count in V exceeds 221 -- the maximum, then post an error message on node N. We use this call 222 -- when we can tell the maximum usage at compile time. In other words, 223 -- we guarantee that if a call is made to this routine, then the front 224 -- end will make all necessary calls for the restriction parameter R 225 -- to ensure that we really know the maximum value used anywhere. 226 227 procedure Check_Restriction (R : Restriction_Parameter_Id; N : Node_Id); 228 -- Check that the maximum value of the restriction parameter corresponding 229 -- to the given restriction parameter identifier is not set to zero. If 230 -- it has been set to zero, post an error message on node N. We use this 231 -- call in cases where we can tell at compile time that the count must be 232 -- at least one, but we can't tell anything more. 233 234 procedure Check_Elaboration_Code_Allowed (N : Node_Id); 235 -- Tests to see if elaboration code is allowed by the current restrictions 236 -- settings. This function is called by Gigi when it needs to define 237 -- an elaboration routine. If elaboration code is not allowed, an error 238 -- message is posted on the node given as argument. 239 240 procedure Check_No_Implicit_Heap_Alloc (N : Node_Id); 241 -- Equivalent to Check_Restriction (No_Implicit_Heap_Allocations, N). 242 -- Provided for easy use by back end, which has to check this restriction. 243 244 function Compilation_Unit_Restrictions_Save 245 return Save_Compilation_Unit_Restrictions; 246 -- This function saves the compilation unit restriction settings, and 247 -- resets them to False. This is used e.g. when compiling a with'ed 248 -- unit to avoid incorrectly propagating restrictions. Note that it 249 -- would not be wrong to also save and reset the partition restrictions, 250 -- since the binder would catch inconsistencies, but actually it is a 251 -- good thing to acquire restrictions from with'ed units if they are 252 -- required to be partition wide, because it allows the restriction 253 -- violation message to be given at compile time instead of link time. 254 255 procedure Compilation_Unit_Restrictions_Restore 256 (R : Save_Compilation_Unit_Restrictions); 257 -- This is the corresponding restore procedure to restore restrictions 258 -- previously saved by Compilation_Unit_Restrictions_Save. 259 260 function Get_Restriction_Id 261 (N : Name_Id) 262 return Restriction_Id; 263 -- Given an identifier name, determines if it is a valid restriction 264 -- identifier, and if so returns the corresponding Restriction_Id 265 -- value, otherwise returns Not_A_Restriction_Id. 266 267 function Get_Restriction_Parameter_Id 268 (N : Name_Id) 269 return Restriction_Parameter_Id; 270 -- Given an identifier name, determines if it is a valid restriction 271 -- parameter identifier, and if so returns the corresponding 272 -- Restriction_Parameter_Id value, otherwise returns 273 -- Not_A_Restriction_Parameter_Id. 274 275 function No_Exception_Handlers_Set return Boolean; 276 -- Test to see if current restrictions settings specify that no exception 277 -- handlers are present. This function is called by Gigi when it needs to 278 -- expand an AT END clean up identifier with no exception handler. 279 280 function Restricted_Profile return Boolean; 281 -- Tests to see if tasking operations follow the GNAT restricted run time 282 -- profile. 283 284 procedure Set_Ravenscar (N : Node_Id); 285 -- Enables the set of restrictions for Ravenscar. N is the corresponding 286 -- pragma node, which is used for error messages on any constructs that 287 -- violate the profile. 288 289 procedure Set_Restricted_Profile (N : Node_Id); 290 -- Enables the set of restrictions for pragma Restricted_Run_Time. N is 291 -- the corresponding pragma node, which is used for error messages on 292 -- constructs that violate the profile. 293 294 function Tasking_Allowed return Boolean; 295 pragma Inline (Tasking_Allowed); 296 -- Tests to see if tasking operations are allowed by the current 297 -- restrictions settings. For tasking to be allowed Max_Tasks must 298 -- be non-zero. 299 300private 301 type Save_Compilation_Unit_Restrictions is 302 array (Compilation_Unit_Restrictions) of Boolean; 303 -- Type used for saving and restoring compilation unit restrictions. 304 -- See Compilation_Unit_Restrictions_[Save|Restore] subprograms. 305 306end Restrict; 307