1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- L I B . L O A D -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2018, 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-- This child package contains the function used to load a separately 27-- compiled unit, as well as the routine used to initialize the unit 28-- table and load the main source file. 29 30package Lib.Load is 31 32 ------------------------------- 33 -- Handling of Renamed Units -- 34 ------------------------------- 35 36 -- A compilation unit can be a renaming of another compilation unit. 37 -- Such renamed units are not allowed as parent units, that is you 38 -- cannot declare a unit: 39 40 -- with x; 41 -- package x.y is end; 42 43 -- where x is a renaming of some other package. However you can refer 44 -- to a renamed unit in a with clause: 45 46 -- package p is end; 47 48 -- package p.q is end; 49 50 -- with p; 51 -- package pr renames p; 52 53 -- with pr.q .... 54 55 -- This means that in the context of a with clause, the normal fixed 56 -- correspondence between unit and file names is broken. In the above 57 -- example, there is no file named pr-q.ads, since the actual child 58 -- unit is p.q, and it will be found in file p-q.ads. 59 60 -- In order to deal with this case, we have to first load pr.ads, and 61 -- then discover that it is a renaming of p, so that we know that pr.q 62 -- really refers to p.q. Furthermore this can happen at any level: 63 64 -- with p.q; 65 -- package p.r renames p.q; 66 67 -- with p.q; 68 -- package p.q.s is end; 69 70 -- with p.r.s ... 71 72 -- Now we have a case where the parent p.r is a child unit and is 73 -- a renaming. This shows that renaming can occur at any level. 74 75 -- Finally, consider: 76 77 -- with pr.q.s ... 78 79 -- Here the parent pr.q is not itself a renaming, but it really refers 80 -- to the unit p.q, and again we cannot know this without loading the 81 -- parent. The bottom line here is that while the file name of a unit 82 -- always corresponds to the unit name, the unit name as given to the 83 -- Load_Unit function may not be the real unit. 84 85 ----------------- 86 -- Subprograms -- 87 ----------------- 88 89 procedure Initialize; 90 -- Initialize internal tables 91 92 procedure Initialize_Version (U : Unit_Number_Type); 93 -- This is called once the source file corresponding to unit U has been 94 -- fully scanned. At that point the checksum is computed, and can be used 95 -- to initialize the version number. 96 97 procedure Load_Main_Source; 98 -- Called at the start of compiling a new main source unit to initialize 99 -- the library processing for the new main source. Establishes and 100 -- initializes the units table entry for the new main unit (leaving 101 -- the Unit_File_Name entry of Main_Unit set to No_File if there are no 102 -- more files. Otherwise the main source file has been opened and read 103 -- and then closed on return. 104 105 function Load_Unit 106 (Load_Name : Unit_Name_Type; 107 Required : Boolean; 108 Error_Node : Node_Id; 109 Subunit : Boolean; 110 Corr_Body : Unit_Number_Type := No_Unit; 111 Renamings : Boolean := False; 112 With_Node : Node_Id := Empty; 113 PMES : Boolean := False) return Unit_Number_Type; 114 -- This function loads and parses the unit specified by Load_Name (or 115 -- returns the unit number for the previously constructed units table 116 -- entry if this is not the first call for this unit). Required indicates 117 -- the behavior on a file not found condition, as further described below, 118 -- and Error_Node is the node in the calling program to which error 119 -- messages are to be attached. 120 -- 121 -- If the corresponding file is found, the value returned by Load is the 122 -- unit number that indexes the corresponding entry in the units table. If 123 -- a serious enough parser error occurs to prevent subsequent semantic 124 -- analysis, then the Fatal_Error flag of the returned entry is set and 125 -- in addition, the fatal error flag of the calling unit is also set. 126 -- 127 -- If the corresponding file is not found, then the behavior depends on 128 -- the setting of Required. If Required is False, then No_Unit is returned 129 -- and no error messages are issued. If Required is True, then an error 130 -- message is posted, and No_Unit is returned. 131 -- 132 -- A special case arises in the call from Rtsfind, where Error_Node is set 133 -- to Empty. In this case Required is False, and the caller in any case 134 -- treats any error as fatal. 135 -- 136 -- The Subunit parameter is True to load a subunit, and False to load 137 -- any other kind of unit (including all specs, package bodies, and 138 -- subprogram bodies). 139 -- 140 -- The Corr_Body argument is normally defaulted. It is set only in the 141 -- case of loading the corresponding spec when the main unit is a body. 142 -- In this case, Corr_Body is the unit number of this corresponding 143 -- body. This is used to set the Serial_Ref_Unit field of the unit 144 -- table entry. It is also used to deal with the special processing 145 -- required by RM 10.1.4(4). See description in lib.ads. 146 -- 147 -- Renamings activates the handling of renamed units as separately 148 -- described in the documentation of this unit. If this parameter is 149 -- set to True, then Load_Name may not be the real unit name and it 150 -- is necessary to load parents to find the real name. 151 -- 152 -- With_Node is set to the with_clause or limited_with_clause causing 153 -- the unit to be loaded, and is used to bypass the circular dependency 154 -- check in the case of a limited_with_clause (Ada 2005, AI-50217). 155 -- 156 -- PMES indicates the required setting of Parsing_Main_Extended_Unit during 157 -- loading of the unit. This flag is saved and restored over the call. 158 -- Note: PMES is false for the subunit case, which seems wrong??? 159 160 procedure Change_Main_Unit_To_Spec; 161 -- This procedure is called if the main unit file contains a No_Body pragma 162 -- and no other tokens. The effect is, if possible, to change the main unit 163 -- from the body it references now, to the corresponding spec. This has the 164 -- effect of ignoring the body, which is what we want. If it is impossible 165 -- to successfully make the change, then the call has no effect, and the 166 -- file is unchanged (this will lead to an error complaining about the 167 -- inappropriate No_Body spec). 168 169 function Create_Dummy_Package_Unit 170 (With_Node : Node_Id; 171 Spec_Name : Unit_Name_Type) return Unit_Number_Type; 172 -- With_Node is the Node_Id of a with statement for which the file could 173 -- not be found, and Spec_Name is the corresponding unit name. This call 174 -- creates a dummy package unit so that compilation can continue without 175 -- blowing up when the missing unit is referenced. 176 177 procedure Make_Child_Decl_Unit (N : Node_Id); 178 -- For a child subprogram body without a spec, we create a subprogram 179 -- declaration in order to attach the required parent link. We create 180 -- a Units_Table entry for this declaration, in order to maintain a 181 -- one-to-one correspondence between compilation units and table entries. 182 183 procedure Make_Instance_Unit (N : Node_Id; In_Main : Boolean); 184 -- When a compilation unit is an instantiation, it contains both the 185 -- declaration and the body of the instance, each of which can have its 186 -- own elaboration routine. The file itself corresponds to the declaration. 187 -- We create an additional entry for the body, so that the binder can 188 -- generate the proper elaboration calls to both. The argument N is the 189 -- compilation unit node created for the body. 190 -- 191 -- If the instance is not the main program, we still generate the instance 192 -- body even though we do not generate code for it. In that case we still 193 -- generate a compilation unit node for it, and we need to make an entry 194 -- for it in the units table, so as to maintain a one-to-one mapping 195 -- between table and nodes. The table entry is used among other things to 196 -- provide a canonical traversal order for context units for CodePeer. 197 -- The flag In_Main indicates whether the instance is the main unit. 198 199 procedure Version_Update (U : Node_Id; From : Node_Id); 200 -- This routine is called when unit U is found to be semantically 201 -- dependent on unit From. It updates the version of U to register 202 -- dependence on the version of From. The arguments are compilation 203 -- unit nodes for the relevant library nodes. 204 205end Lib.Load; 206