diff options
Diffstat (limited to 'gcc/ada/ali-util.ads')
| -rw-r--r-- | gcc/ada/ali-util.ads | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/gcc/ada/ali-util.ads b/gcc/ada/ali-util.ads index ace733a4acd..9cfefb70c83 100644 --- a/gcc/ada/ali-util.ads +++ b/gcc/ada/ali-util.ads @@ -6,9 +6,9 @@ -- -- -- S p e c -- -- -- --- $Revision: 1.2 $ -- +-- $Revision$ -- -- --- Copyright (C) 1992-1999 Free Software Foundation, Inc. -- +-- Copyright (C) 1992-2001 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- -- @@ -130,12 +130,26 @@ package ALI.Util is -- 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 : Name_Id) 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 - -- affecte by a mis-computation. Returns an impossible checksum value, - -- with the upper bit set, if the file is missing or has an error. + -- 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; |