1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- A L I . U T I L -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2013, 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 unit provides utility data structures and procedures used 27-- for manipulation of ALI data by the gnatbind and gnatmake. 28 29package ALI.Util is 30 31 ----------------------- 32 -- Source File Table -- 33 ----------------------- 34 35 -- A table entry is built for every source file that is in the source 36 -- dependency table of any ALI file that is part of the current program. 37 38 No_Source_Id : constant Source_Id := Source_Id'First; 39 -- Special value indicating no Source table entry 40 41 First_Source_Entry : constant Source_Id := No_Source_Id + 1; 42 -- Id of first actual entry in table 43 44 type Source_Record is record 45 46 Sfile : File_Name_Type; 47 -- Name of source file 48 49 Stamp : Time_Stamp_Type; 50 -- Time stamp value. If Check_Source_Files is set and the source 51 -- file is located, then Stamp is set from the source file. Otherwise 52 -- Stamp is set from the latest stamp value found in any of the 53 -- ALI files for the current program. 54 55 Source_Found : Boolean; 56 -- This flag is set to True if the corresponding source file was 57 -- located and the Stamp value was set from the actual source file. 58 -- It is always false if Check_Source_Files is not set. 59 60 Stamp_File : File_Name_Type; 61 -- File that Stamp came from. If Source_Found is True, then Stamp is the 62 -- timestamp of the source file, and this is the name of the source 63 -- file. If Source_Found is False, then Stamp comes from a dependency 64 -- line in an ALI file, this is the name of that ALI file. Used only in 65 -- verbose mode, for messages. 66 67 All_Timestamps_Match : Boolean; 68 -- This flag is set only if all files referencing this source file 69 -- have a matching time stamp, and also, if Source_Found is True, 70 -- then the stamp of the source file also matches. If this flag is 71 -- True, then checksums for this file are never referenced. We only 72 -- use checksums if there are time stamp mismatches. 73 74 All_Checksums_Match : Boolean; 75 -- This flag is set only if all files referencing this source file 76 -- have checksums, and if all these checksums match. If this flag 77 -- is set to True, then the binder will ignore a timestamp mismatch. 78 -- An absent checksum causes this flag to be set False, and a mismatch 79 -- of checksums also causes it to be set False. The checksum of the 80 -- actual source file (if Source_Found is True) is included only if 81 -- All_Timestamps_Match is False (since checksums are only interesting 82 -- if we have time stamp mismatches, and we want to avoid computing the 83 -- checksum of the source file if it is not needed.) 84 85 Checksum : Word; 86 -- If no dependency line has a checksum for this source file (i.e. the 87 -- corresponding entries in the source dependency records all have the 88 -- Checksum_Present flag set False), then this field is undefined. If 89 -- at least one dependency entry has a checksum present, then this 90 -- field contains one of the possible checksum values that has been 91 -- seen. This is used to set All_Checksums_Match properly. 92 93 end record; 94 95 package Source is new Table.Table ( 96 Table_Component_Type => Source_Record, 97 Table_Index_Type => Source_Id, 98 Table_Low_Bound => First_Source_Entry, 99 Table_Initial => 1000, 100 Table_Increment => 200, 101 Table_Name => "Source"); 102 103 procedure Initialize_ALI_Source; 104 -- Initialize Source table 105 106 -------------------------------------------------- 107 -- Subprograms for Manipulating ALI Information -- 108 -------------------------------------------------- 109 110 procedure Read_Withed_ALIs 111 (Id : ALI_Id; 112 Ignore_Errors : Boolean := False); 113 -- Process an ALI file which has been read and scanned by looping through 114 -- all withed units in the ALI file, checking if they have been processed. 115 -- Each unit that has not yet been processed will be read, scanned, and 116 -- processed recursively. If Ignore_Errors is True, then failure to read an 117 -- ALI file is not reported as an error, and scanning continues with other 118 -- ALI files. 119 120 procedure Set_Source_Table (A : ALI_Id); 121 -- Build source table entry corresponding to the ALI file whose id is A 122 123 procedure Set_Source_Table; 124 -- Build the entire source table 125 126 function Time_Stamp_Mismatch 127 (A : ALI_Id; 128 Read_Only : Boolean := False) return File_Name_Type; 129 -- Looks in the Source_Table and checks time stamp mismatches between 130 -- the sources there and the sources in the Sdep section of ali file whose 131 -- id is A. If no time stamp mismatches are found No_File is returned. 132 -- Otherwise return the first file for which there is a mismatch. 133 -- Note that in check source files mode (Check_Source_Files = True), the 134 -- time stamp in the Source_Table should be the actual time stamp of the 135 -- source files. In minimal recompilation mode (Minimal_Recompilation set 136 -- to True, no mismatch is found if the file's timestamp has not changed. 137 -- If Read_Only is True, missing sources are not considered. 138 139 -------------------------------------------- 140 -- Subprograms for manipulating checksums -- 141 -------------------------------------------- 142 143 Checksum_Error : constant Word := 16#FFFF_FFFF#; 144 -- This value is used to indicate an error in computing the checksum. 145 -- When comparing checksums for smart recompilation, the CRC_Error 146 -- value is never considered to match. This could possibly result 147 -- in a false negative, but that is never harmful, it just means 148 -- that in unusual cases an unnecessary recompilation occurs. 149 150 function Get_File_Checksum (Fname : File_Name_Type) return Word; 151 -- Compute checksum for the given file. As far as possible, this circuit 152 -- computes exactly the same value computed by the compiler, but it does 153 -- not matter if it gets it wrong in marginal cases, since the only result 154 -- is to miss some smart recompilation cases, correct functioning is not 155 -- affected by a miscomputation. Returns Checksum_Error if the file is 156 -- missing or has an error. 157 158 function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean; 159 pragma Inline (Checksums_Match); 160 -- Returns True if Checksum1 and Checksum2 have the same value and are 161 -- not equal to Checksum_Error, returns False in all other cases. This 162 -- routine must always be used to compare for checksum equality, to 163 -- ensure that the case of Checksum_Error is handled properly. 164 165end ALI.Util; 166