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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- A L I . U T I L --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This child unit provides utility data structures and procedures used
-- for manipulation of ALI data by the gnatbind and gnatmake.
package ALI.Util is
-----------------------
-- Source File Table --
-----------------------
-- A table entry is built for every source file that is in the source
-- dependency table of any ALI file that is part of the current program.
No_Source_Id : constant Source_Id := Source_Id'First;
-- Special value indicating no Source table entry
First_Source_Entry : constant Source_Id := No_Source_Id + 1;
-- Id of first actual entry in table
type Source_Record is record
Sfile : File_Name_Type;
-- Name of source file
Stamp : Time_Stamp_Type;
-- Time stamp value. If Check_Source_Files is set and the source
-- file is located, then Stamp is set from the source file. Otherwise
-- Stamp is set from the latest stamp value found in any of the
-- ALI files for the current program.
Source_Found : Boolean;
-- This flag is set to True if the corresponding source file was
-- located and the Stamp value was set from the actual source file.
-- It is always false if Check_Source_Files is not set.
All_Timestamps_Match : Boolean;
-- This flag is set only if all files referencing this source file
-- have a matching time stamp, and also, if Source_Found is True,
-- then the stamp of the source file also matches. If this flag is
-- True, then checksums for this file are never referenced. We only
-- use checksums if there are time stamp mismatches.
All_Checksums_Match : Boolean;
-- This flag is set only if all files referencing this source file
-- have checksums, and if all these checksums match. If this flag
-- is set to True, then the binder will ignore a timestamp mismatch.
-- An absent checksum causes this flag to be set False, and a mismatch
-- of checksums also causes it to be set False. The checksum of the
-- actual source file (if Source_Found is True) is included only if
-- All_Timestamps_Match is False (since checksums are only interesting
-- if we have time stamp mismatches, and we want to avoid computing the
-- checksum of the source file if it is not needed.)
Checksum : Word;
-- If no dependency line has a checksum for this source file (i.e. the
-- corresponding entries in the source dependency records all have the
-- Checksum_Present flag set False), then this field is undefined. If
-- at least one dependency entry has a checksum present, then this
-- field contains one of the possible checksum values that has been
-- seen. This is used to set All_Checksums_Match properly.
end record;
package Source is new Table.Table (
Table_Component_Type => Source_Record,
Table_Index_Type => Source_Id,
Table_Low_Bound => First_Source_Entry,
Table_Initial => 1000,
Table_Increment => 200,
Table_Name => "Source");
procedure Initialize_ALI_Source;
-- Initialize Source table
--------------------------------------------------
-- Subprograms for Manipulating ALI Information --
--------------------------------------------------
procedure Read_Withed_ALIs (Id : ALI_Id);
-- Process an ALI file which has been read and scanned by looping through
-- all withed units in the ALI file, checking if they have been processed.
-- Each unit that has not yet been processed will be read, scanned, and
-- processed recursively.
procedure Set_Source_Table (A : ALI_Id);
-- Build source table entry corresponding to the ALI file whose id is A
procedure Set_Source_Table;
-- Build the entire source table
function Time_Stamp_Mismatch
(A : ALI_Id;
Read_Only : Boolean := False) return File_Name_Type;
-- Looks in the Source_Table and checks time stamp mismatches between
-- the sources there and the sources in the Sdep section of ali file whose
-- id is A. If no time stamp mismatches are found No_File is returned.
-- Otherwise return the first file for which there is a mismatch.
-- Note that in check source files mode (Check_Source_Files = True), the
-- time stamp in the Source_Table should be the actual time stamp of the
-- source files. In minimal recompilation mode (Minimal_Recompilation set
-- to True, no mismatch is found if the file's timestamp has not changed.
-- If Read_Only is True, missing sources are not considered.
--------------------------------------------
-- Subprograms for manipulating checksums --
--------------------------------------------
Checksum_Error : constant Word := 16#FFFF_FFFF#;
-- This value is used to indicate an error in computing the checksum.
-- When comparing checksums for smart recompilation, the CRC_Error
-- value is never considered to match. This could possibly result
-- in a false negative, but that is never harmful, it just means
-- that in unusual cases an unnecessary recompilation occurs.
function Get_File_Checksum (Fname : File_Name_Type) return Word;
-- Compute checksum for the given file. As far as possible, this circuit
-- computes exactly the same value computed by the compiler, but it does
-- not matter if it gets it wrong in marginal cases, since the only result
-- is to miss some smart recompilation cases, correct functioning is not
-- affected by a miscomputation. Returns Checksum_Error if the file is
-- missing or has an error.
function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean;
pragma Inline (Checksums_Match);
-- Returns True if Checksum1 and Checksum2 have the same value and are
-- not equal to Checksum_Error, returns False in all other cases. This
-- routine must always be used to compare for checksum equality, to
-- ensure that the case of Checksum_Error is handled properly.
end ALI.Util;
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