1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ P R A G -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2015, 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 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. -- 20-- -- 21-- GNAT was originally developed by the GNAT team at New York University. -- 22-- Extensive contributions were provided by Ada Core Technologies Inc. -- 23-- -- 24------------------------------------------------------------------------------ 25 26-- Pragma handling is isolated in a separate package 27-- (logically this processing belongs in chapter 4) 28 29with Namet; use Namet; 30with Opt; use Opt; 31with Snames; use Snames; 32with Types; use Types; 33 34package Sem_Prag is 35 36 -- The following table lists all pragmas that act as an assertion 37 -- expression. 38 39 Assertion_Expression_Pragma : constant array (Pragma_Id) of Boolean := 40 (Pragma_Assert => True, 41 Pragma_Assert_And_Cut => True, 42 Pragma_Assume => True, 43 Pragma_Check => True, 44 Pragma_Contract_Cases => True, 45 Pragma_Initial_Condition => True, 46 Pragma_Invariant => True, 47 Pragma_Loop_Invariant => True, 48 Pragma_Loop_Variant => True, 49 Pragma_Post => True, 50 Pragma_Post_Class => True, 51 Pragma_Postcondition => True, 52 Pragma_Pre => True, 53 Pragma_Pre_Class => True, 54 Pragma_Precondition => True, 55 Pragma_Predicate => True, 56 Pragma_Refined_Post => True, 57 Pragma_Test_Case => True, 58 Pragma_Type_Invariant => True, 59 Pragma_Type_Invariant_Class => True, 60 others => False); 61 62 -- The following table lists all the implementation-defined pragmas that 63 -- may apply to a body stub (no language defined pragmas apply). The table 64 -- should be synchronized with Aspect_On_Body_Or_Stub_OK in unit Aspects if 65 -- the pragmas below implement an aspect. 66 67 Pragma_On_Body_Or_Stub_OK : constant array (Pragma_Id) of Boolean := 68 (Pragma_Refined_Depends => True, 69 Pragma_Refined_Global => True, 70 Pragma_Refined_Post => True, 71 Pragma_SPARK_Mode => True, 72 Pragma_Warnings => True, 73 others => False); 74 75 ----------------- 76 -- Subprograms -- 77 ----------------- 78 79 procedure Analyze_Pragma (N : Node_Id); 80 -- Analyze procedure for pragma reference node N 81 82 procedure Analyze_Contract_Cases_In_Decl_Part (N : Node_Id); 83 -- Perform full analysis and expansion of delayed pragma Contract_Cases 84 85 procedure Analyze_Depends_In_Decl_Part (N : Node_Id); 86 -- Perform full analysis of delayed pragma Depends. This routine is also 87 -- capable of performing basic analysis of pragma Refined_Depends. 88 89 procedure Analyze_External_Property_In_Decl_Part 90 (N : Node_Id; 91 Expr_Val : out Boolean); 92 -- Perform full analysis of delayed pragmas Async_Readers, Async_Writers, 93 -- Effective_Reads and Effective_Writes. Flag Expr_Val contains the Boolean 94 -- argument of the pragma or a default True if no argument is present. 95 96 procedure Analyze_Global_In_Decl_Part (N : Node_Id); 97 -- Perform full analysis of delayed pragma Global. This routine is also 98 -- capable of performing basic analysis of pragma Refind_Global. 99 100 procedure Analyze_Initial_Condition_In_Decl_Part (N : Node_Id); 101 -- Perform full analysis of delayed pragma Initial_Condition 102 103 procedure Analyze_Initializes_In_Decl_Part (N : Node_Id); 104 -- Perform full analysis of delayed pragma Initializes 105 106 procedure Analyze_Pre_Post_Condition_In_Decl_Part (N : Node_Id); 107 -- Perform preanalysis of [refined] precondition or postcondition pragma 108 -- N that appears on a subprogram declaration or body [stub]. 109 110 procedure Analyze_Refined_Depends_In_Decl_Part (N : Node_Id); 111 -- Preform full analysis of delayed pragma Refined_Depends. This routine 112 -- uses Analyze_Depends_In_Decl_Part as a starting point, then performs 113 -- various consistency checks between Depends and Refined_Depends. 114 115 procedure Analyze_Refined_Global_In_Decl_Part (N : Node_Id); 116 -- Perform full analysis of delayed pragma Refined_Global. This routine 117 -- uses Analyze_Global_In_Decl_Part as a starting point, then performs 118 -- various consistency checks between Global and Refined_Global. 119 120 procedure Analyze_Refined_State_In_Decl_Part (N : Node_Id); 121 -- Perform full analysis of delayed pragma Refined_State 122 123 procedure Analyze_Test_Case_In_Decl_Part (N : Node_Id); 124 -- Perform preanalysis of pragma Test_Case 125 126 procedure Check_Applicable_Policy (N : Node_Id); 127 -- N is either an N_Aspect or an N_Pragma node. There are two cases. If 128 -- the name of the aspect or pragma is not one of those recognized as 129 -- an assertion kind by an Assertion_Policy pragma, then the call has 130 -- no effect. Note that in the case of a pragma derived from an aspect, 131 -- the name we use for the purpose of this procedure is the aspect name, 132 -- which may be different from the pragma name (e.g. Precondition for 133 -- Pre aspect). In addition, 'Class aspects are recognized (and the 134 -- corresponding special names used in the processing). 135 -- 136 -- If the name is a valid assertion kind name, then the Check_Policy pragma 137 -- chain is checked for a matching entry (or for an Assertion entry which 138 -- matches all possibilities). If a matching entry is found then the policy 139 -- is checked. If it is On or Check, then the Is_Checked flag is set in 140 -- the aspect or pragma node. If it is Off, Ignore, or Disable, then the 141 -- Is_Ignored flag is set in the aspect or pragma node. Additionally for 142 -- policy Disable, the Is_Disabled flag is set. 143 -- 144 -- If no matching Check_Policy pragma is found then the effect depends on 145 -- whether -gnata was used, if so, then the call has no effect, otherwise 146 -- Is_Ignored (but not Is_Disabled) is set True. 147 148 procedure Check_External_Properties 149 (Item : Node_Id; 150 AR : Boolean; 151 AW : Boolean; 152 ER : Boolean; 153 EW : Boolean); 154 -- Flags AR, AW, ER and EW denote the static values of external properties 155 -- Async_Readers, Async_Writers, Effective_Reads and Effective_Writes. Item 156 -- is the related variable or state. Ensure legality of the combination and 157 -- issue an error for an illegal combination. 158 159 procedure Check_Missing_Part_Of (Item_Id : Entity_Id); 160 -- Determine whether the placement within the state space of an abstract 161 -- state, variable or package instantiation denoted by Item_Id requires the 162 -- use of indicator/option Part_Of. If this is the case, emit an error. 163 164 procedure Collect_Subprogram_Inputs_Outputs 165 (Subp_Id : Entity_Id; 166 Synthesize : Boolean := False; 167 Subp_Inputs : in out Elist_Id; 168 Subp_Outputs : in out Elist_Id; 169 Global_Seen : out Boolean); 170 -- Subsidiary to the analysis of pragmas Depends, Global, Refined_Depends 171 -- and Refined_Global. The routine is also used by GNATprove. Collect all 172 -- inputs and outputs of subprogram Subp_Id in lists Subp_Inputs (inputs) 173 -- and Subp_Outputs (outputs). The inputs and outputs are gathered from: 174 -- 1) The formal parameters of the subprogram 175 -- 2) The items of pragma [Refined_]Global 176 -- or 177 -- 3) The items of pragma [Refined_]Depends if there is no pragma 178 -- [Refined_]Global present and flag Synthesize is set to True. 179 -- If the subprogram has no inputs and/or outputs, then the returned list 180 -- is No_Elist. Flag Global_Seen is set when the related subprogram has 181 -- pragma [Refined_]Global. 182 183 function Delay_Config_Pragma_Analyze (N : Node_Id) return Boolean; 184 -- N is a pragma appearing in a configuration pragma file. Most such 185 -- pragmas are analyzed when the file is read, before parsing and analyzing 186 -- the main unit. However, the analysis of certain pragmas results in 187 -- adding information to the compiled main unit, and this cannot be done 188 -- till the main unit is processed. Such pragmas return True from this 189 -- function and in Frontend pragmas where Delay_Config_Pragma_Analyze is 190 -- True have their analysis delayed until after the main program is parsed 191 -- and analyzed. 192 193 function Find_Related_Subprogram_Or_Body 194 (Prag : Node_Id; 195 Do_Checks : Boolean := False) return Node_Id; 196 -- Subsidiary to the analysis of pragmas Contract_Cases, Depends, Global, 197 -- Refined_Depends, Refined_Global and Refined_Post and attribute 'Result. 198 -- Find the declaration of the related subprogram [body or stub] subject 199 -- to pragma Prag. If flag Do_Checks is set, the routine reports duplicate 200 -- pragmas and detects improper use of refinement pragmas in stand alone 201 -- expression functions. The returned value depends on the related pragma 202 -- as follows: 203 -- 1) Pragmas Contract_Cases, Depends and Global yield the corresponding 204 -- N_Subprogram_Declaration node or if the pragma applies to a stand 205 -- alone body, the N_Subprogram_Body node or Empty if illegal. 206 -- 2) Pragmas Refined_Depends, Refined_Global and Refined_Post yield 207 -- N_Subprogram_Body or N_Subprogram_Body_Stub nodes or Empty if 208 -- illegal. 209 210 function Get_SPARK_Mode_From_Pragma (N : Node_Id) return SPARK_Mode_Type; 211 -- Given a pragma SPARK_Mode node, return corresponding mode id 212 213 procedure Initialize; 214 -- Initializes data structures used for pragma processing. Must be called 215 -- before analyzing each new main source program. 216 217 function Is_Config_Static_String (Arg : Node_Id) return Boolean; 218 -- This is called for a configuration pragma that requires either string 219 -- literal or a concatenation of string literals. We cannot use normal 220 -- static string processing because it is too early in the case of the 221 -- pragma appearing in a configuration pragmas file. If Arg is of an 222 -- appropriate form, then this call obtains the string (doing any necessary 223 -- concatenations) and places it in Name_Buffer, setting Name_Len to its 224 -- length, and then returns True. If it is not of the correct form, then an 225 -- appropriate error message is posted, and False is returned. 226 227 function Is_Elaboration_SPARK_Mode (N : Node_Id) return Boolean; 228 -- Determine whether pragma SPARK_Mode appears in the statement part of a 229 -- package body. 230 231 function Is_Non_Significant_Pragma_Reference (N : Node_Id) return Boolean; 232 -- The node N is a node for an entity and the issue is whether the 233 -- occurrence is a reference for the purposes of giving warnings about 234 -- unreferenced variables. This function returns True if the reference is 235 -- not a reference from this point of view (e.g. the occurrence in a pragma 236 -- Pack) and False if it is a real reference (e.g. the occurrence in a 237 -- pragma Export); 238 239 function Is_Pragma_String_Literal (Par : Node_Id) return Boolean; 240 -- Given an N_Pragma_Argument_Association node, Par, which has the form of 241 -- an operator symbol, determines whether or not it should be treated as an 242 -- string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol. If 243 -- True is returned, the argument is converted to a string literal. If 244 -- False is returned, then the argument is treated as an entity reference 245 -- to the operator. 246 247 function Is_Private_SPARK_Mode (N : Node_Id) return Boolean; 248 -- Determine whether pragma SPARK_Mode appears in the private part of a 249 -- package. 250 251 function Is_Valid_Assertion_Kind (Nam : Name_Id) return Boolean; 252 -- Returns True if Nam is one of the names recognized as a valid assertion 253 -- kind by the Assertion_Policy pragma. Note that the 'Class cases are 254 -- represented by the corresponding special names Name_uPre, Name_uPost, 255 -- Name_uInvariant, and Name_uType_Invariant (_Pre, _Post, _Invariant, 256 -- and _Type_Invariant). 257 258 procedure Process_Compilation_Unit_Pragmas (N : Node_Id); 259 -- Called at the start of processing compilation unit N to deal with any 260 -- special issues regarding pragmas. In particular, we have to deal with 261 -- Suppress_All at this stage, since it can appear after the unit instead 262 -- of before (actually we allow it to appear anywhere). 263 264 procedure Relocate_Pragmas_To_Body 265 (Subp_Body : Node_Id; 266 Target_Body : Node_Id := Empty); 267 -- Resocate all pragmas that follow and apply to subprogram body Subp_Body 268 -- to its own declaration list. Candidate pragmas are classified in table 269 -- Pragma_On_Body_Or_Stub_OK. If Target_Body is set, the pragma are moved 270 -- to the declarations of Target_Body. This formal should be set when 271 -- dealing with subprogram body stubs or expression functions. 272 273 procedure Set_Encoded_Interface_Name (E : Entity_Id; S : Node_Id); 274 -- This routine is used to set an encoded interface name. The node S is 275 -- an N_String_Literal node for the external name to be set, and E is an 276 -- entity whose Interface_Name field is to be set. In the normal case where 277 -- S contains a name that is a valid C identifier, then S is simply set as 278 -- the value of the Interface_Name. Otherwise it is encoded as needed by 279 -- particular operating systems. See the body for details of the encoding. 280 281 function Test_Case_Arg 282 (Prag : Node_Id; 283 Arg_Nam : Name_Id; 284 From_Aspect : Boolean := False) return Node_Id; 285 -- Obtain argument "Name", "Mode", "Ensures" or "Requires" from Test_Case 286 -- pragma Prag as denoted by Arg_Nam. When From_Aspect is set, an attempt 287 -- is made to retrieve the argument from the corresponding aspect if there 288 -- is one. The returned argument has several formats: 289 -- 290 -- N_Pragma_Argument_Association if retrieved directly from the pragma 291 -- 292 -- N_Component_Association if retrieved from the corresponding aspect and 293 -- the argument appears in a named association form. 294 -- 295 -- An arbitrary expression if retrieved from the corresponding aspect and 296 -- the argument appears in positional form. 297 -- 298 -- Empty if there is no such argument 299 300end Sem_Prag; 301