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) 1992-2011, 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 All_Timestamps_Match : Boolean; 61 -- This flag is set only if all files referencing this source file 62 -- have a matching time stamp, and also, if Source_Found is True, 63 -- then the stamp of the source file also matches. If this flag is 64 -- True, then checksums for this file are never referenced. We only 65 -- use checksums if there are time stamp mismatches. 66 67 All_Checksums_Match : Boolean; 68 -- This flag is set only if all files referencing this source file 69 -- have checksums, and if all these checksums match. If this flag 70 -- is set to True, then the binder will ignore a timestamp mismatch. 71 -- An absent checksum causes this flag to be set False, and a mismatch 72 -- of checksums also causes it to be set False. The checksum of the 73 -- actual source file (if Source_Found is True) is included only if 74 -- All_Timestamps_Match is False (since checksums are only interesting 75 -- if we have time stamp mismatches, and we want to avoid computing the 76 -- checksum of the source file if it is not needed.) 77 78 Checksum : Word; 79 -- If no dependency line has a checksum for this source file (i.e. the 80 -- corresponding entries in the source dependency records all have the 81 -- Checksum_Present flag set False), then this field is undefined. If 82 -- at least one dependency entry has a checksum present, then this 83 -- field contains one of the possible checksum values that has been 84 -- seen. This is used to set All_Checksums_Match properly. 85 86 end record; 87 88 package Source is new Table.Table ( 89 Table_Component_Type => Source_Record, 90 Table_Index_Type => Source_Id, 91 Table_Low_Bound => First_Source_Entry, 92 Table_Initial => 1000, 93 Table_Increment => 200, 94 Table_Name => "Source"); 95 96 procedure Initialize_ALI_Source; 97 -- Initialize Source table 98 99 -------------------------------------------------- 100 -- Subprograms for Manipulating ALI Information -- 101 -------------------------------------------------- 102 103 procedure Read_Withed_ALIs 104 (Id : ALI_Id; 105 Ignore_Errors : Boolean := False); 106 -- Process an ALI file which has been read and scanned by looping through 107 -- all withed units in the ALI file, checking if they have been processed. 108 -- Each unit that has not yet been processed will be read, scanned, and 109 -- processed recursively. If Ignore_Errors is True, then failure to read an 110 -- ALI file is not reported as an error, and scanning continues with other 111 -- ALI files. 112 113 procedure Set_Source_Table (A : ALI_Id); 114 -- Build source table entry corresponding to the ALI file whose id is A 115 116 procedure Set_Source_Table; 117 -- Build the entire source table 118 119 function Time_Stamp_Mismatch 120 (A : ALI_Id; 121 Read_Only : Boolean := False) return File_Name_Type; 122 -- Looks in the Source_Table and checks time stamp mismatches between 123 -- the sources there and the sources in the Sdep section of ali file whose 124 -- id is A. If no time stamp mismatches are found No_File is returned. 125 -- Otherwise return the first file for which there is a mismatch. 126 -- Note that in check source files mode (Check_Source_Files = True), the 127 -- time stamp in the Source_Table should be the actual time stamp of the 128 -- source files. In minimal recompilation mode (Minimal_Recompilation set 129 -- to True, no mismatch is found if the file's timestamp has not changed. 130 -- If Read_Only is True, missing sources are not considered. 131 132 -------------------------------------------- 133 -- Subprograms for manipulating checksums -- 134 -------------------------------------------- 135 136 Checksum_Error : constant Word := 16#FFFF_FFFF#; 137 -- This value is used to indicate an error in computing the checksum. 138 -- When comparing checksums for smart recompilation, the CRC_Error 139 -- value is never considered to match. This could possibly result 140 -- in a false negative, but that is never harmful, it just means 141 -- that in unusual cases an unnecessary recompilation occurs. 142 143 function Get_File_Checksum (Fname : File_Name_Type) return Word; 144 -- Compute checksum for the given file. As far as possible, this circuit 145 -- computes exactly the same value computed by the compiler, but it does 146 -- not matter if it gets it wrong in marginal cases, since the only result 147 -- is to miss some smart recompilation cases, correct functioning is not 148 -- affected by a miscomputation. Returns Checksum_Error if the file is 149 -- missing or has an error. 150 151 function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean; 152 pragma Inline (Checksums_Match); 153 -- Returns True if Checksum1 and Checksum2 have the same value and are 154 -- not equal to Checksum_Error, returns False in all other cases. This 155 -- routine must always be used to compare for checksum equality, to 156 -- ensure that the case of Checksum_Error is handled properly. 157 158end ALI.Util; 159