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) 1992-2003 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 child unit provides utility data structures and procedures used 28-- for manipulation of ALI data by the gnatbind and gnatmake. 29 30package ALI.Util is 31 32 ----------------------- 33 -- Source File Table -- 34 ----------------------- 35 36 -- A source file table entry is built for every source file that is 37 -- in the source dependency table of any of the ALI files that make 38 -- up the current program. 39 40 No_Source_Id : constant Source_Id := Source_Id'First; 41 -- Special value indicating no Source table entry 42 43 First_Source_Entry : constant Source_Id := No_Source_Id + 1; 44 -- Id of first actual entry in table 45 46 type Source_Record is record 47 48 Sfile : File_Name_Type; 49 -- Name of source file 50 51 Stamp : Time_Stamp_Type; 52 -- Time stamp value. If Check_Source_Files is set and the source 53 -- file is located, then Stamp is set from the source file. Otherwise 54 -- Stamp is set from the latest stamp value found in any of the 55 -- ALI files for the current program. 56 57 Source_Found : Boolean; 58 -- This flag is set to True if the corresponding source file was 59 -- located and the Stamp value was set from the actual source file. 60 -- It is always false if Check_Source_Files is not set. 61 62 All_Timestamps_Match : Boolean; 63 -- This flag is set only if all files referencing this source file 64 -- have a matching time stamp, and also, if Source_Found is True, 65 -- then the stamp of the source file also matches. If this flag is 66 -- True, then checksums for this file are never referenced. We only 67 -- use checksums if there are time stamp mismatches. 68 69 All_Checksums_Match : Boolean; 70 -- This flag is set only if all files referencing this source file 71 -- have checksums, and if all these checksums match. If this flag 72 -- is set to True, then the binder will ignore a timestamp mismatch. 73 -- An absent checksum causes this flag to be set False, and a mismatch 74 -- of checksums also causes it to be set False. The checksum of the 75 -- actual source file (if Source_Found is True) is included only if 76 -- All_Timestamps_Match is False (since checksums are only interesting 77 -- if we have time stamp mismatches, and we want to avoid computing the 78 -- checksum of the source file if it is not needed.) 79 80 Checksum : Word; 81 -- If no dependency line has a checksum for this source file (i.e. the 82 -- corresponding entries in the source dependency records all have the 83 -- Checksum_Present flag set False), then this field is undefined. If 84 -- at least one dependency entry has a checksum present, then this 85 -- field contains one of the possible checksum values that has been 86 -- seen. This is used to set All_Checksums_Match properly. 87 88 end record; 89 90 package Source is new Table.Table ( 91 Table_Component_Type => Source_Record, 92 Table_Index_Type => Source_Id, 93 Table_Low_Bound => First_Source_Entry, 94 Table_Initial => 1000, 95 Table_Increment => 200, 96 Table_Name => "Source"); 97 98 procedure Initialize_ALI_Source; 99 -- Initialize Source table 100 101 -------------------------------------------------- 102 -- Subprograms for Manipulating ALI Information -- 103 -------------------------------------------------- 104 105 procedure Read_ALI (Id : ALI_Id); 106 -- Process an ALI file which has been read and scanned by looping 107 -- through all withed units in the ALI file, checking if they have 108 -- been processed. Each unit that has not yet been processed will 109 -- be read, scanned, and processed recursively. 110 111 procedure Set_Source_Table (A : ALI_Id); 112 -- Build source table entry corresponding to the ALI file whose id is A. 113 114 procedure Set_Source_Table; 115 -- Build the entire source table. 116 117 function Time_Stamp_Mismatch 118 (A : ALI_Id; 119 Read_Only : Boolean := False) 120 return File_Name_Type; 121 -- Looks in the Source_Table and checks time stamp mismatches between 122 -- the sources there and the sources in the Sdep section of ali file whose 123 -- id is A. If no time stamp mismatches are found No_File is returned. 124 -- Otherwise return the first file for which there is a mismatch. 125 -- Note that in check source files mode (Check_Source_Files = True), the 126 -- time stamp in the Source_Table should be the actual time stamp of the 127 -- source files. In minimal recompilation mode (Minimal_Recompilation set 128 -- to True, no mismatch is found if the file's timestamp has not changed. 129 -- If Read_Only is True, missing sources are not considered. 130 131 -------------------------------------------- 132 -- Subprograms for manipulating checksums -- 133 -------------------------------------------- 134 135 Checksum_Error : constant Word := 16#FFFF_FFFF#; 136 -- This value is used to indicate an error in computing the checksum. 137 -- When comparing checksums for smart recompilation, the CRC_Error 138 -- value is never considered to match. This could possibly result 139 -- in a false negative, but that is never harmful, it just means 140 -- that in unusual cases an unnecessary recompilation occurs. 141 142 function Get_File_Checksum (Fname : Name_Id) return Word; 143 -- Compute checksum for the given file. As far as possible, this circuit 144 -- computes exactly the same value computed by the compiler, but it does 145 -- not matter if it gets it wrong in marginal cases, since the only result 146 -- is to miss some smart recompilation cases, correct functioning is not 147 -- affected by a miscomputation. Returns Checksum_Error if the file is 148 -- missing or has an error. 149 150 function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean; 151 pragma Inline (Checksums_Match); 152 -- Returns True if Checksum1 and Checksum2 have the same value and are 153 -- not equal to Checksum_Error, returns False in all other cases. This 154 -- routine must always be used to compare for checksum equality, to 155 -- ensure that the case of Checksum_Error is handled properly. 156 157end ALI.Util; 158