* Makefile.in:

	(GNAT_ADA_OBJS): add g-crc32.o, a-tags.o, a-stream.o
	(GNATBIND_OBJS): add g-crc32.o, a-tags.o, a-stream.o
	(GNATLS_RTL_OBJS): add g-crc32.o
	(GNATMAKE_RTL_OBJS): add g-crc32.o

	* ali-util.adb:
	(CRC_Match): new function.
	(Get_File_Checksum): renamed Get_File_CRC. Use the GNAT.CRC32 unit
	instead of the previous simple checksum algorithm.
	(Time_Stamp_Mismatch): use CRC_Match for comparison.
	(Set_Source_Table): idem.

	* ali-util.ads:
	(Get_File_Checksum): renamed Get_File_CRC as now we compute CRC
	instead of simple checksum.
	(CRC_Match): new function.
	(CRC_Error): new constant.

	* ali.adb (Scan_ALI): rename variable Chk to CRC as we are handling
	a CRC now and not a simple checksum. A CRC uses lower-case hex
	letters, fixes ambiguity in parsing.

	* ali.ads (Sdep_Record.Checksum): renamed Sdep_Record.CRC as this
	is what this variable will store.

	* bcheck.adb: Change reference to chechsum in comments by CRC.
	(Check_Consistency): Rename Get_File_Checksum to Get_File_CRC.
	rename All_Checksum_Match to All_CRC_Match. Change due to API
	renaming since now GNAT does not use a simple checksum but a
	CRC using GNAT.CRC32.

	* gnatls.adb: Rename Checksum to CRC in many places, we use a CRC
	now and not anymore a simple checksum.

	* lib-load.adb: Use Source_CRC instead of Source_Checksum in many
	places.

	* lib-writ.adb (Write_ALI): Use Source_CRC instead of Source_Checksum.

	* scans.adb:
	(Restore_Scan_State): rename Checksum to CRC.
	(Save_Scan_State): idem.

	* scans.ads:
	With GNAT.CRC32.
	(Checksum): rename to CRC.
	(Saved_Scan_State): Save_Checksum field renamed to Save_CRC

	* scn-nlit.adb: Rename many Accumulate_Checksum to Update (from
	GNAT.CRC32).  Update copyright notice.

	* scn-slit.adb: Rename many Accumulate_Checksum to Update (from
	GNAT.CRC32).  Update copyright notice.

	* scn.adb:
	(Accumulate_Checksum): removed.
	(Update): new procedure. Add a wide-character into the CRC.

	* sinput-l.adb:
	(Complete_Source_File_Entry): use CRC32 instead of simple checksum.
	(Load_File): fix initialization of S (change Source_Checksum to
	Source_CRC)

	* sinput-p.adb (Load_Project_File): rename Source_Checksum to
	Source_CRC in S initialization.

	* sinput.adb (Source_Checksum): renamed to Source_CRC.

	* sinput.ads (Source_Checksum): renamed to Source_CRC.
	Update comments for the CRC.

	* types.adb (Hex): Use lowercase for the letter part.

	* types.ads (Get_Hex_String): Returns the hexadecimal representation
	for a word. This is currently used only for CRC. In previous version,
	the checksum was using a representation with all letter being
	upper-case. With the new implementation (using CRC) we do not remove
	the 32th bit of the CRC, so we can have an upper-case starting letter
	in the CRC. This is not possible to parse in Scan_ALI (ali.adb).
	It is ambigous since the CRC was optional and could be followed by
	options like EB, EE. So now this routines uses lower-case letter for
	the hexadecimal representation. Strange enough only lower case letters
	where checked in Scan_ALI (even if this was not a possible case).

	* gnatvsn.ads (Library_Version): changed to 3.15a.

	* s-crc32.ads: Initial version from GNAT.CRC32. This is the version
	for the compiler.

	* s-crc32.adb: Initial version from GNAT.CRC32. This is the version
	for the compiler.

	* ali-util.adb: Redo previous change to avoid using word CRC everywhere
	Add 2001 to copyright notice
	(Accumulate_Checksum): Modify to use System.CRC32.

	* ali-util.ads: Redo changes of previous revision to continue to use
	the word Checksum. Add 2001 to copyright notice.

	* ali.adb: Undo some of previous changes, not needed.
	Keep the change for lower case letters in the checksum.

	* ali.ads: Undo previous change not needed.

	* bcheck.adb: Undo most of previous change, not needed.
	But do use Checksums_Match for checksum comparison.

	* gnatls.adb: Undo most of previous change, not needed.
	But do use Checksums_Match for comparing checksums.

	* lib-load.adb: Undo previous change, not needed.

	* lib-writ.adb: Undo previous change, not needed.

	* lib-writ.ads: Document that checksums use lower case,
	not upper case letters.

	* scans.adb: Undo previous change, not needed

	* scans.ads: Undo previous change, not needed.

	* scn-nlit.adb: Undo previous changes, not needed.

	* scn-slit.adb: Undo previous change, not needed.  Fix header format.

	* scn.adb:
	(Accumulate_Checksum): Use System.CRC32.
	(Initialize_Checksum): New procedure.
	Remove other changes of previous revision.

	* sinput-p.adb: Undo previous change, not needed.

	* sinput.adb: Undo previous change, not needed.

	* sinput-l.adb: Undo previous change, not needed.

	* sinput.ads: Undo previous change, not needed.  Keep only comment
	on new checksum algorithm

	* Makefile.in: Add s-crc32 as needed, remove g-crc32.
	Also remove a-tags and a-stream from GNAT sources.

	* ali.adb (Scan_ALI): fix typo introduce in latest check-in.

	* Makefile.in (GNATRTL_NONTASKING_OBJS): Add g-crc32.o.

From-SVN: r46206

20 files changed, 702 insertions, 85 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 8d79567..889ac48 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,152 @@
+2001-10-11  Pascal Obry <obry@gnat.com>
+
+	* Makefile.in:
+	(GNAT_ADA_OBJS): add g-crc32.o, a-tags.o, a-stream.o
+	(GNATBIND_OBJS): add g-crc32.o, a-tags.o, a-stream.o
+	(GNATLS_RTL_OBJS): add g-crc32.o
+	(GNATMAKE_RTL_OBJS): add g-crc32.o
+	
+	* ali-util.adb:
+	(CRC_Match): new function.
+	(Get_File_Checksum): renamed Get_File_CRC. Use the GNAT.CRC32 unit 
+	instead of the previous simple checksum algorithm.
+	(Time_Stamp_Mismatch): use CRC_Match for comparison.
+	(Set_Source_Table): idem.
+	
+	* ali-util.ads:
+	(Get_File_Checksum): renamed Get_File_CRC as now we compute CRC 
+	instead of simple checksum.
+	(CRC_Match): new function.
+	(CRC_Error): new constant.
+	
+	* ali.adb (Scan_ALI): rename variable Chk to CRC as we are handling 
+	a CRC now and not a simple checksum. A CRC uses lower-case hex 
+	letters, fixes ambiguity in parsing.
+	
+	* ali.ads (Sdep_Record.Checksum): renamed Sdep_Record.CRC as this 
+	is what this variable will store.
+	
+	* bcheck.adb: Change reference to chechsum in comments by CRC.
+	(Check_Consistency): Rename Get_File_Checksum to Get_File_CRC. 
+	rename All_Checksum_Match to All_CRC_Match. Change due to API 
+	renaming since now GNAT does not use a simple checksum but a 
+	CRC using GNAT.CRC32.
+	
+	* gnatls.adb: Rename Checksum to CRC in many places, we use a CRC 
+	now and not anymore a simple checksum.
+	
+	* lib-load.adb: Use Source_CRC instead of Source_Checksum in many 
+	places.
+	
+	* lib-writ.adb (Write_ALI): Use Source_CRC instead of Source_Checksum.
+	
+	* scans.adb:
+	(Restore_Scan_State): rename Checksum to CRC.
+	(Save_Scan_State): idem.
+	
+	* scans.ads:
+	With GNAT.CRC32.
+	(Checksum): rename to CRC.
+	(Saved_Scan_State): Save_Checksum field renamed to Save_CRC
+	
+	* scn-nlit.adb: Rename many Accumulate_Checksum to Update (from 
+	GNAT.CRC32).  Update copyright notice.
+	
+	* scn-slit.adb: Rename many Accumulate_Checksum to Update (from 
+	GNAT.CRC32).  Update copyright notice.
+	
+	* scn.adb:
+	(Accumulate_Checksum): removed.
+	(Update): new procedure. Add a wide-character into the CRC.
+	
+	* sinput-l.adb:
+	(Complete_Source_File_Entry): use CRC32 instead of simple checksum.
+	(Load_File): fix initialization of S (change Source_Checksum to 
+	Source_CRC)
+	
+	* sinput-p.adb (Load_Project_File): rename Source_Checksum to 
+	Source_CRC in S initialization.
+	
+	* sinput.adb (Source_Checksum): renamed to Source_CRC.
+	
+	* sinput.ads (Source_Checksum): renamed to Source_CRC.
+	Update comments for the CRC.
+	
+	* types.adb (Hex): Use lowercase for the letter part.
+	
+	* types.ads (Get_Hex_String): Returns the hexadecimal representation 
+	for a word. This is currently used only for CRC. In previous version, 
+	the checksum was using a representation with all letter being 
+	upper-case. With the new implementation (using CRC) we do not remove 
+	the 32th bit of the CRC, so we can have an upper-case starting letter 
+	in the CRC. This is not possible to parse in Scan_ALI (ali.adb). 
+	It is ambigous since the CRC was optional and could be followed by 
+	options like EB, EE. So now this routines uses lower-case letter for 
+	the hexadecimal representation. Strange enough only lower case letters 
+	where checked in Scan_ALI (even if this was not a possible case).
+	
+	* gnatvsn.ads (Library_Version): changed to 3.15a.
+	
+	* s-crc32.ads: Initial version from GNAT.CRC32. This is the version 
+	for the compiler.
+	
+	* s-crc32.adb: Initial version from GNAT.CRC32. This is the version 
+	for the compiler.
+	
+	* ali-util.adb: Redo previous change to avoid using word CRC everywhere
+	Add 2001 to copyright notice
+	(Accumulate_Checksum): Modify to use System.CRC32.
+	
+	* ali-util.ads: Redo changes of previous revision to continue to use 
+	the word Checksum. Add 2001 to copyright notice.
+	
+	* ali.adb: Undo some of previous changes, not needed.
+	Keep the change for lower case letters in the checksum.
+	
+	* ali.ads: Undo previous change not needed.
+
+	* bcheck.adb: Undo most of previous change, not needed.
+	But do use Checksums_Match for checksum comparison.
+	
+	* gnatls.adb: Undo most of previous change, not needed.
+	But do use Checksums_Match for comparing checksums.
+	
+	* lib-load.adb: Undo previous change, not needed.
+	
+	* lib-writ.adb: Undo previous change, not needed.
+	
+	* lib-writ.ads: Document that checksums use lower case, 
+	not upper case letters.
+	
+	* scans.adb: Undo previous change, not needed
+	
+	* scans.ads: Undo previous change, not needed.
+	
+	* scn-nlit.adb: Undo previous changes, not needed.
+	
+	* scn-slit.adb: Undo previous change, not needed.  Fix header format.
+	
+	* scn.adb:
+	(Accumulate_Checksum): Use System.CRC32.
+	(Initialize_Checksum): New procedure.
+	Remove other changes of previous revision.
+	
+	* sinput-p.adb: Undo previous change, not needed.
+	
+	* sinput.adb: Undo previous change, not needed.
+
+	* sinput-l.adb: Undo previous change, not needed.
+	
+	* sinput.ads: Undo previous change, not needed.  Keep only comment 
+	on new checksum algorithm
+	
+	* Makefile.in: Add s-crc32 as needed, remove g-crc32.
+	Also remove a-tags and a-stream from GNAT sources.
+	
+	* ali.adb (Scan_ALI): fix typo introduce in latest check-in.
+	
+	* Makefile.in (GNATRTL_NONTASKING_OBJS): Add g-crc32.o.
+
 2001-10-11  Geert Bosch  <bosch@gnat.com>
 
 	* einfo.h: Regenerate.
diff --git a/gcc/ada/Makefile.in b/gcc/ada/Makefile.in
index 75a56d2..df2a68c 100644
--- a/gcc/ada/Makefile.in
+++ b/gcc/ada/Makefile.in
@@ -299,16 +299,16 @@ GNAT1_C_OBJS = b_gnat1.o adaint.o cstreams.o cio.o targtyps.o decl.o \
 # Object files from Ada sources that are used by gnat1
 
 GNAT_ADA_OBJS = \
- ada.o a-charac.o a-chlat1.o a-except.o s-memory.o s-traceb.o s-mastop.o \
- s-except.o ali.o alloc.o atree.o butil.o casing.o checks.o comperr.o     \
- csets.o cstand.o debug.o debug_a.o einfo.o elists.o errout.o eval_fat.o \
- exp_attr.o exp_ch11.o exp_ch12.o exp_ch13.o exp_ch2.o exp_ch3.o exp_ch4.o \
- exp_ch5.o exp_ch6.o exp_ch7.o exp_ch8.o exp_ch9.o exp_code.o exp_dbug.o \
- exp_disp.o exp_dist.o exp_fixd.o exp_aggr.o exp_imgv.o \
+ ada.o a-charac.o a-chlat1.o a-except.o s-memory.o \
+ s-traceb.o s-mastop.o s-except.o ali.o alloc.o atree.o butil.o casing.o \
+ checks.o comperr.o csets.o cstand.o debug.o debug_a.o einfo.o elists.o \
+ errout.o eval_fat.o exp_attr.o exp_ch11.o exp_ch12.o exp_ch13.o exp_ch2.o \
+ exp_ch3.o exp_ch4.o exp_ch5.o exp_ch6.o exp_ch7.o exp_ch8.o exp_ch9.o \
+ exp_code.o exp_dbug.o exp_disp.o exp_dist.o exp_fixd.o exp_aggr.o exp_imgv.o \
  exp_intr.o exp_pakd.o exp_prag.o exp_smem.o \
  exp_strm.o exp_tss.o exp_util.o exp_vfpt.o expander.o fname.o fname-uf.o \
  freeze.o frontend.o gnat.o g-hesora.o g-htable.o g-os_lib.o \
- g-speche.o get_targ.o gnatvsn.o \
+ g-speche.o s-crc32.o get_targ.o gnatvsn.o \
  hlo.o hostparm.o impunit.o \
  interfac.o itypes.o inline.o krunch.o lib.o \
  layout.o lib-load.o lib-util.o lib-xref.o lib-writ.o live.o \
@@ -339,7 +339,7 @@ GNATBIND_OBJS = \
  butil.o casing.o csets.o \
  debug.o fname.o gnat.o g-hesora.o g-htable.o \
  g-os_lib.o gnatbind.o gnatvsn.o hostparm.o \
- krunch.o namet.o opt.o osint.o output.o rident.o s-assert.o \
+ krunch.o namet.o opt.o osint.o output.o rident.o s-crc32.o s-assert.o \
  s-parame.o s-sopco3.o s-sopco4.o s-sopco5.o s-stache.o s-stalib.o \
  s-stoele.o s-imgenu.o s-strops.o s-soflin.o s-wchcon.o s-wchjis.o \
  sdefault.o switch.o stylesw.o validsw.o \
@@ -392,7 +392,7 @@ GNATKR_RTL_OBJS = ada.o a-charac.o a-chahan.o a-chlat1.o a-comlin.o \
   a-filico.o  s-strops.o  s-stratt.o s-imgenu.o a-ioexce.o s-exctab.o
 GNATKR_OBJS = gnatkr.o gnatvsn.o \
   krunch.o hostparm.o $(GNATKR_RTL_OBJS) $(EXTRA_GNATTOOLS_OBJS)
- 
+
 GNATLINK_RTL_OBJS = \
    adaint.o argv.o cio.o cstreams.o \
    exit.o init.o final.o raise.o tracebak.o \
@@ -451,6 +451,7 @@ GNATLS_RTL_OBJS = \
  system.o   \
  s-assert.o \
  s-bitops.o \
+ s-crc32.o  \
  s-except.o \
  s-exctab.o \
  s-finroo.o \
@@ -478,6 +479,7 @@ GNATLS_RTL_OBJS = \
  s-wchcnv.o \
  s-wchcon.o \
  s-wchjis.o
+
 GNATLS_OBJS = \
  ali.o      \
  ali-util.o \
@@ -553,7 +555,7 @@ GNATMAKE_RTL_OBJS = adaint.o argv.o raise.o exit.o a-comlin.o \
  s-imgenu.o s-assert.o s-secsta.o s-stoele.o s-soflin.o s-fileio.o \
  s-valenu.o s-valuti.o g-casuti.o \
  system.o s-exctab.o s-strops.o s-sopco3.o s-sopco4.o s-sopco5.o \
- g-htable.o g-regexp.o s-wchcnv.o
+ g-htable.o g-regexp.o s-crc32.o s-wchcnv.o
 
 GNATMAKE_OBJS = ali.o ali-util.o \
  alloc.o atree.o binderr.o butil.o casing.o csets.o debug.o einfo.o elists.o \
@@ -1666,6 +1668,7 @@ GNATRTL_NONTASKING_OBJS= \
   g-cgicoo.o \
   g-cgideb.o \
   g-comlin.o \
+  g-crc32.o \
   g-curexc.o \
   g-debuti.o \
   g-debpoo.o \
@@ -1715,6 +1718,7 @@ GNATRTL_NONTASKING_OBJS= \
   s-auxdec.o \
   s-bitops.o \
   s-chepoo.o \
+  s-crc32.o  \
   s-direio.o \
   s-errrep.o \
   s-except.o \
@@ -3930,6 +3934,8 @@ s-assert.o : ada.ads a-except.ads gnat.ads g-htable.ads system.ads \
 s-bitops.o : gnat.ads g-except.ads system.ads s-bitops.ads s-bitops.adb \
    s-unstyp.ads unchconv.ads 
 
+s-crc32.o : interfac.ads system.ads s-crc32.ads s-crc32.adb
+
 s-except.o : ada.ads a-except.ads system.ads s-except.ads s-stalib.ads \
    unchconv.ads 
 
diff --git a/gcc/ada/ali-util.adb b/gcc/ada/ali-util.adb
index 58312cd..0e0ded9 100644
--- a/gcc/ada/ali-util.adb
+++ b/gcc/ada/ali-util.adb
@@ -6,9 +6,9 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.7 $
+--                            $Revision$
 --                                                                          --
---          Copyright (C) 1992-2000 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- --
@@ -31,6 +31,8 @@ with Namet;   use Namet;
 with Opt;     use Opt;
 with Osint;   use Osint;
 
+with System.CRC32;
+
 package body ALI.Util is
 
    -----------------------
@@ -48,19 +50,27 @@ package body ALI.Util is
    --  generate code, so it is not necessary to worry about making the right
    --  sequence of calls in any error situation.
 
+   procedure Initialize_Checksum (Csum : in out Word);
+   --  Sets initial value of Csum before any calls to Accumulate_Checksum
+
    -------------------------
    -- Accumulate_Checksum --
    -------------------------
 
    procedure Accumulate_Checksum (C : Character; Csum : in out Word) is
    begin
-      Csum := Csum + Csum + Character'Pos (C);
-
-      if Csum > 16#8000_0000# then
-         Csum := (Csum + 1) and 16#7FFF_FFFF#;
-      end if;
+      System.CRC32.Update (System.CRC32.CRC32 (Csum), C);
    end Accumulate_Checksum;
 
+   ---------------------
+   -- Checksums_Match --
+   ---------------------
+
+   function Checksums_Match (Checksum1, Checksum2 : Word) return Boolean is
+   begin
+      return Checksum1 = Checksum2 and then Checksum1 /= Checksum_Error;
+   end Checksums_Match;
+
    -----------------------
    -- Get_File_Checksum --
    -----------------------
@@ -101,7 +111,7 @@ package body ALI.Util is
          raise Bad;
       end if;
 
-      Csum := 0;
+      Initialize_Checksum (Csum);
       Ptr := 0;
 
       loop
@@ -249,7 +259,7 @@ package body ALI.Util is
    exception
       when Bad =>
          Free_Source;
-         return 16#FFFF_FFFF#;
+         return Checksum_Error;
 
    end Get_File_Checksum;
 
@@ -272,6 +282,15 @@ package body ALI.Util is
       Source.Init;
    end Initialize_ALI_Source;
 
+   -------------------------
+   -- Initialize_Checksum --
+   -------------------------
+
+   procedure Initialize_Checksum (Csum : in out Word) is
+   begin
+      System.CRC32.Initialize (System.CRC32.CRC32 (Csum));
+   end Initialize_Checksum;
+
    --------------
    -- Read_ALI --
    --------------
@@ -406,7 +425,9 @@ package body ALI.Util is
 
             --  Update checksum flag
 
-            if Sdep.Table (D).Checksum /= Source.Table (S).Checksum then
+            if not Checksums_Match
+                     (Sdep.Table (D).Checksum, Source.Table (S).Checksum)
+            then
                Source.Table (S).All_Checksums_Match := False;
             end if;
 
@@ -492,8 +513,9 @@ package body ALI.Util is
             --  ??? It is probably worth updating the ALI file with a new
             --  field to avoid recomputing it each time.
 
-            if Get_File_Checksum (Sdep.Table (D).Sfile) =
-                                             Source.Table (Src).Checksum
+            if Checksums_Match
+                 (Get_File_Checksum (Sdep.Table (D).Sfile),
+                  Source.Table (Src).Checksum)
             then
                Sdep.Table (D).Stamp := Source.Table (Src).Stamp;
             end if;
diff --git a/gcc/ada/ali-util.ads b/gcc/ada/ali-util.ads
index ace733a..9cfefb7 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;
diff --git a/gcc/ada/ali.adb b/gcc/ada/ali.adb
index 0909b38..db6a0f2 100644
--- a/gcc/ada/ali.adb
+++ b/gcc/ada/ali.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.124 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -1143,9 +1143,9 @@ package body ALI is
                   Chk := Chk * 16 +
                            Character'Pos (Nextc) - Character'Pos ('0');
 
-               elsif Nextc in 'A' .. 'F' then
+               elsif Nextc in 'a' .. 'f' then
                   Chk := Chk * 16 +
-                           Character'Pos (Nextc) - Character'Pos ('A') + 10;
+                           Character'Pos (Nextc) - Character'Pos ('a') + 10;
 
                else
                   exit;
diff --git a/gcc/ada/bcheck.adb b/gcc/ada/bcheck.adb
index 1d38f96..c4da7574 100644
--- a/gcc/ada/bcheck.adb
+++ b/gcc/ada/bcheck.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.39 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -511,8 +511,9 @@ package body Bcheck is
          --  with the checksums in the ALI files.
 
          elsif Check_Source_Files then
-            if Source.Table (S).Checksum /=
-               Get_File_Checksum (Source.Table (S).Sfile)
+            if not Checksums_Match
+              (Source.Table (S).Checksum,
+               Get_File_Checksum (Source.Table (S).Sfile))
             then
                Source.Table (S).All_Checksums_Match := False;
             end if;
diff --git a/gcc/ada/g-crc32.adb b/gcc/ada/g-crc32.adb
new file mode 100644
index 0000000..e7ed74c
--- /dev/null
+++ b/gcc/ada/g-crc32.adb
@@ -0,0 +1,92 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT LIBRARY COMPONENTS                          --
+--                                                                          --
+--                           G N A T . C R C 3 2                            --
+--                                                                          --
+--                                 B o d y                                  --
+--                                                                          --
+--                            $Revision$
+--                                                                          --
+--              Copyright (C) 2001 Ada Core Technologies, 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 2,  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 COPYING.  If not, write --
+-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
+-- MA 02111-1307, USA.                                                      --
+--                                                                          --
+-- As a special exception,  if other files  instantiate  generics from this --
+-- unit, or you link  this unit with other files  to produce an executable, --
+-- this  unit  does not  by itself cause  the resulting  executable  to  be --
+-- covered  by the  GNU  General  Public  License.  This exception does not --
+-- however invalidate  any other reasons why  the executable file  might be --
+-- covered by the  GNU Public License.                                      --
+--                                                                          --
+-- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com).   --
+--                                                                          --
+------------------------------------------------------------------------------
+
+with Unchecked_Conversion;
+
+package body GNAT.CRC32 is
+
+   ------------
+   -- Update --
+   ------------
+
+   procedure Update (C : in out CRC32; Value : String) is
+   begin
+      for K in Value'Range loop
+         Update (C, Value (K));
+      end loop;
+   end Update;
+
+   procedure Update (C : in out CRC32; Value : Ada.Streams.Stream_Element) is
+      function To_Char is new Unchecked_Conversion
+        (Ada.Streams.Stream_Element, Character);
+
+      V : constant Character := To_Char (Value);
+
+   begin
+      Update (C, V);
+   end Update;
+
+   procedure Update
+     (C     : in out CRC32;
+      Value : Ada.Streams.Stream_Element_Array)
+   is
+   begin
+      for K in Value'Range loop
+         Update (C, Value (K));
+      end loop;
+   end Update;
+
+   -----------------
+   -- Wide_Update --
+   -----------------
+
+   procedure Wide_Update (C : in out CRC32; Value : Wide_Character) is
+      subtype S2 is String (1 .. 2);
+      function To_S2 is new Unchecked_Conversion (Wide_Character, S2);
+
+      VS : S2 := To_S2 (Value);
+
+   begin
+      Update (C, VS (1));
+      Update (C, VS (2));
+   end Wide_Update;
+
+   procedure Wide_Update (C : in out CRC32; Value : Wide_String) is
+   begin
+      for K in Value'Range loop
+         Wide_Update (C, Value (K));
+      end loop;
+   end Wide_Update;
+
+end GNAT.CRC32;
diff --git a/gcc/ada/g-crc32.ads b/gcc/ada/g-crc32.ads
new file mode 100644
index 0000000..ab16a36
--- /dev/null
+++ b/gcc/ada/g-crc32.ads
@@ -0,0 +1,117 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT LIBRARY COMPONENTS                          --
+--                                                                          --
+--                           G N A T . C R C 3 2                            --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--                            $Revision$
+--                                                                          --
+--              Copyright (C) 2001 Ada Core Technologies, 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 2,  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 COPYING.  If not, write --
+-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
+-- MA 02111-1307, USA.                                                      --
+--                                                                          --
+-- As a special exception,  if other files  instantiate  generics from this --
+-- unit, or you link  this unit with other files  to produce an executable, --
+-- this  unit  does not  by itself cause  the resulting  executable  to  be --
+-- covered  by the  GNU  General  Public  License.  This exception does not --
+-- however invalidate  any other reasons why  the executable file  might be --
+-- covered by the  GNU Public License.                                      --
+--                                                                          --
+-- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com).   --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  This package provides routines for computing a commonly used checksum
+--  called CRC-32. This is a checksum based on treating the binary data
+--  as a polynomial over a binary field, and the exact specifications of
+--  the CRC-32 algorithm are as follows:
+--
+--     Name   : "CRC-32"
+--     Width  : 32
+--     Poly   : 04C11DB7
+--     Init   : FFFFFFFF
+--     RefIn  : True
+--     RefOut : True
+--     XorOut : FFFFFFFF
+--     Check  : CBF43926
+--
+--  Note that this is the algorithm used by PKZip, Ethernet and FDDI.
+--
+--  For more information about this algorithm see:
+--
+--  ftp://ftp.rocksoft.com/papers/crc_v3.txt
+
+--  "A Painless Guide to CRC Error Detection Algorithms", Ross N. Williams
+--
+--  "Computation of Cyclic Redundancy Checks via Table Look-Up", Communications
+--  of the ACM, Vol. 31 No. 8, pp.1008-1013 Aug. 1988. Sarwate, D.V.
+
+with Ada.Streams;
+with Interfaces;
+with System.CRC32;
+
+package GNAT.CRC32 is
+
+   subtype CRC32 is System.CRC32.CRC32;
+   --  Used to represent CRC32 values, which are 32 bit bit-strings
+
+   procedure Initialize (C : out CRC32)
+     renames System.CRC32.Initialize;
+   --  Initialize CRC value by assigning the standard Init value (16#FFFF_FFFF)
+
+   procedure Update
+     (C     : in out CRC32;
+      Value : Character)
+     renames System.CRC32.Update;
+   --  Evolve CRC by including the contribution from Character'Pos (Value)
+
+   procedure Update
+     (C     : in out CRC32;
+      Value : String);
+   pragma Inline (Update);
+   --  For each character in the Value string call above routine
+
+   procedure Wide_Update
+     (C     : in out CRC32;
+      Value : Wide_Character);
+   pragma Inline (Update);
+   --  Evolve CRC by including the contribution from Wide_Character'Pos (Value)
+   --  with the bytes being included in the natural memory order.
+
+   procedure Wide_Update
+     (C     : in out CRC32;
+      Value : Wide_String);
+   pragma Inline (Update);
+   --  For each character in the Value string call above routine
+
+   procedure Update
+     (C     : in out CRC32;
+      Value : Ada.Streams.Stream_Element);
+   pragma Inline (Update);
+   --  Evolve CRC by including the contribution from Value
+
+   procedure Update
+     (C     : in out CRC32;
+      Value : Ada.Streams.Stream_Element_Array);
+   pragma Inline (Update);
+   --  For each element in the Value array call above routine
+
+   function Get_Value (C : CRC32) return Interfaces.Unsigned_32
+     renames System.CRC32.Get_Value;
+   --  Get_Value computes the CRC32 value by performing an XOR with the
+   --  standard XorOut value (16#FFFF_FFFF). Note that this does not
+   --  change the value of C, so it may be used to retrieve intermediate
+   --  values of the CRC32 value during a sequence of Update calls.
+
+end GNAT.CRC32;
diff --git a/gcc/ada/gnatls.adb b/gcc/ada/gnatls.adb
index b131ddb..f5446e8 100644
--- a/gcc/ada/gnatls.adb
+++ b/gcc/ada/gnatls.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.37 $
+--                            $Revision$
 --                                                                          --
 --           Copyright (C) 1992-2001 Free Software Foundation, Inc.         --
 --                                                                          --
@@ -352,7 +352,7 @@ procedure Gnatls is
          FS     := Tmp1;
          Status := OK;
 
-      elsif Get_File_Checksum (FS) = Checksum then
+      elsif Checksums_Match (Get_File_Checksum (FS), Checksum) then
          FS := Tmp1;
          Status := Checksum_OK;
 
diff --git a/gcc/ada/gnatvsn.ads b/gcc/ada/gnatvsn.ads
index a6f27cd..9287832 100644
--- a/gcc/ada/gnatvsn.ads
+++ b/gcc/ada/gnatvsn.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---                            $Revision: 1.2068 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -54,7 +54,7 @@ package Gnatvsn is
    --  value should never be decreased in the future, but it would be
    --  OK to increase it if absolutely necessary.
 
-   Library_Version : constant String := "GNAT Lib v3.15 ";
+   Library_Version : constant String := "GNAT Lib v3.15a";
    --  Library version. This value must be updated whenever any change to the
    --  compiler affects the library formats in such a way as to obsolete
    --  previously compiled library modules.
diff --git a/gcc/ada/lib-writ.ads b/gcc/ada/lib-writ.ads
index f4ca41a..75621d7 100644
--- a/gcc/ada/lib-writ.ads
+++ b/gcc/ada/lib-writ.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---                            $Revision: 1.14 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -411,7 +411,7 @@ package Lib.Writ is
    --      time stamp representation.
 
    --      The checksum is an 8-hex digit representation of the source
-   --      file checksum, with letters given in upper case.
+   --      file checksum, with letters given in lower case.
 
    --      The subunit name is present only if the dependency line is for
    --      a subunit. It contains the fully qualified name of the subunit
diff --git a/gcc/ada/s-crc32.adb b/gcc/ada/s-crc32.adb
new file mode 100644
index 0000000..120914b
--- /dev/null
+++ b/gcc/ada/s-crc32.adb
@@ -0,0 +1,139 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT LIBRARY COMPONENTS                          --
+--                                                                          --
+--                        S Y S T E M  . C R C 3 2                          --
+--                                                                          --
+--                                 B o d y                                  --
+--                                                                          --
+--                            $Revision$
+--                                                                          --
+--              Copyright (C) 2001 Ada Core Technologies, 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 2,  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 COPYING.  If not, write --
+-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
+-- MA 02111-1307, USA.                                                      --
+--                                                                          --
+-- As a special exception,  if other files  instantiate  generics from this --
+-- unit, or you link  this unit with other files  to produce an executable, --
+-- this  unit  does not  by itself cause  the resulting  executable  to  be --
+-- covered  by the  GNU  General  Public  License.  This exception does not --
+-- however invalidate  any other reasons why  the executable file  might be --
+-- covered by the  GNU Public License.                                      --
+--                                                                          --
+-- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com).   --
+--                                                                          --
+------------------------------------------------------------------------------
+
+package body System.CRC32 is
+
+   Init   : constant CRC32 := 16#FFFF_FFFF#;  -- Initial value
+   XorOut : constant CRC32 := 16#FFFF_FFFF#;  -- To compute final result.
+
+   --  The following table contains precomputed values for contributions
+   --  from various possible byte values. Doing a table lookup is quicker
+   --  than processing the byte bit by bit.
+
+   Table : array (CRC32 range 0 .. 255) of CRC32 :=
+     (16#0000_0000#, 16#7707_3096#, 16#EE0E_612C#, 16#9909_51BA#,
+      16#076D_C419#, 16#706A_F48F#, 16#E963_A535#, 16#9E64_95A3#,
+      16#0EDB_8832#, 16#79DC_B8A4#, 16#E0D5_E91E#, 16#97D2_D988#,
+      16#09B6_4C2B#, 16#7EB1_7CBD#, 16#E7B8_2D07#, 16#90BF_1D91#,
+      16#1DB7_1064#, 16#6AB0_20F2#, 16#F3B9_7148#, 16#84BE_41DE#,
+      16#1ADA_D47D#, 16#6DDD_E4EB#, 16#F4D4_B551#, 16#83D3_85C7#,
+      16#136C_9856#, 16#646B_A8C0#, 16#FD62_F97A#, 16#8A65_C9EC#,
+      16#1401_5C4F#, 16#6306_6CD9#, 16#FA0F_3D63#, 16#8D08_0DF5#,
+      16#3B6E_20C8#, 16#4C69_105E#, 16#D560_41E4#, 16#A267_7172#,
+      16#3C03_E4D1#, 16#4B04_D447#, 16#D20D_85FD#, 16#A50A_B56B#,
+      16#35B5_A8FA#, 16#42B2_986C#, 16#DBBB_C9D6#, 16#ACBC_F940#,
+      16#32D8_6CE3#, 16#45DF_5C75#, 16#DCD6_0DCF#, 16#ABD1_3D59#,
+      16#26D9_30AC#, 16#51DE_003A#, 16#C8D7_5180#, 16#BFD0_6116#,
+      16#21B4_F4B5#, 16#56B3_C423#, 16#CFBA_9599#, 16#B8BD_A50F#,
+      16#2802_B89E#, 16#5F05_8808#, 16#C60C_D9B2#, 16#B10B_E924#,
+      16#2F6F_7C87#, 16#5868_4C11#, 16#C161_1DAB#, 16#B666_2D3D#,
+      16#76DC_4190#, 16#01DB_7106#, 16#98D2_20BC#, 16#EFD5_102A#,
+      16#71B1_8589#, 16#06B6_B51F#, 16#9FBF_E4A5#, 16#E8B8_D433#,
+      16#7807_C9A2#, 16#0F00_F934#, 16#9609_A88E#, 16#E10E_9818#,
+      16#7F6A_0DBB#, 16#086D_3D2D#, 16#9164_6C97#, 16#E663_5C01#,
+      16#6B6B_51F4#, 16#1C6C_6162#, 16#8565_30D8#, 16#F262_004E#,
+      16#6C06_95ED#, 16#1B01_A57B#, 16#8208_F4C1#, 16#F50F_C457#,
+      16#65B0_D9C6#, 16#12B7_E950#, 16#8BBE_B8EA#, 16#FCB9_887C#,
+      16#62DD_1DDF#, 16#15DA_2D49#, 16#8CD3_7CF3#, 16#FBD4_4C65#,
+      16#4DB2_6158#, 16#3AB5_51CE#, 16#A3BC_0074#, 16#D4BB_30E2#,
+      16#4ADF_A541#, 16#3DD8_95D7#, 16#A4D1_C46D#, 16#D3D6_F4FB#,
+      16#4369_E96A#, 16#346E_D9FC#, 16#AD67_8846#, 16#DA60_B8D0#,
+      16#4404_2D73#, 16#3303_1DE5#, 16#AA0A_4C5F#, 16#DD0D_7CC9#,
+      16#5005_713C#, 16#2702_41AA#, 16#BE0B_1010#, 16#C90C_2086#,
+      16#5768_B525#, 16#206F_85B3#, 16#B966_D409#, 16#CE61_E49F#,
+      16#5EDE_F90E#, 16#29D9_C998#, 16#B0D0_9822#, 16#C7D7_A8B4#,
+      16#59B3_3D17#, 16#2EB4_0D81#, 16#B7BD_5C3B#, 16#C0BA_6CAD#,
+      16#EDB8_8320#, 16#9ABF_B3B6#, 16#03B6_E20C#, 16#74B1_D29A#,
+      16#EAD5_4739#, 16#9DD2_77AF#, 16#04DB_2615#, 16#73DC_1683#,
+      16#E363_0B12#, 16#9464_3B84#, 16#0D6D_6A3E#, 16#7A6A_5AA8#,
+      16#E40E_CF0B#, 16#9309_FF9D#, 16#0A00_AE27#, 16#7D07_9EB1#,
+      16#F00F_9344#, 16#8708_A3D2#, 16#1E01_F268#, 16#6906_C2FE#,
+      16#F762_575D#, 16#8065_67CB#, 16#196C_3671#, 16#6E6B_06E7#,
+      16#FED4_1B76#, 16#89D3_2BE0#, 16#10DA_7A5A#, 16#67DD_4ACC#,
+      16#F9B9_DF6F#, 16#8EBE_EFF9#, 16#17B7_BE43#, 16#60B0_8ED5#,
+      16#D6D6_A3E8#, 16#A1D1_937E#, 16#38D8_C2C4#, 16#4FDF_F252#,
+      16#D1BB_67F1#, 16#A6BC_5767#, 16#3FB5_06DD#, 16#48B2_364B#,
+      16#D80D_2BDA#, 16#AF0A_1B4C#, 16#3603_4AF6#, 16#4104_7A60#,
+      16#DF60_EFC3#, 16#A867_DF55#, 16#316E_8EEF#, 16#4669_BE79#,
+      16#CB61_B38C#, 16#BC66_831A#, 16#256F_D2A0#, 16#5268_E236#,
+      16#CC0C_7795#, 16#BB0B_4703#, 16#2202_16B9#, 16#5505_262F#,
+      16#C5BA_3BBE#, 16#B2BD_0B28#, 16#2BB4_5A92#, 16#5CB3_6A04#,
+      16#C2D7_FFA7#, 16#B5D0_CF31#, 16#2CD9_9E8B#, 16#5BDE_AE1D#,
+      16#9B64_C2B0#, 16#EC63_F226#, 16#756A_A39C#, 16#026D_930A#,
+      16#9C09_06A9#, 16#EB0E_363F#, 16#7207_6785#, 16#0500_5713#,
+      16#95BF_4A82#, 16#E2B8_7A14#, 16#7BB1_2BAE#, 16#0CB6_1B38#,
+      16#92D2_8E9B#, 16#E5D5_BE0D#, 16#7CDC_EFB7#, 16#0BDB_DF21#,
+      16#86D3_D2D4#, 16#F1D4_E242#, 16#68DD_B3F8#, 16#1FDA_836E#,
+      16#81BE_16CD#, 16#F6B9_265B#, 16#6FB0_77E1#, 16#18B7_4777#,
+      16#8808_5AE6#, 16#FF0F_6A70#, 16#6606_3BCA#, 16#1101_0B5C#,
+      16#8F65_9EFF#, 16#F862_AE69#, 16#616B_FFD3#, 16#166C_CF45#,
+      16#A00A_E278#, 16#D70D_D2EE#, 16#4E04_8354#, 16#3903_B3C2#,
+      16#A767_2661#, 16#D060_16F7#, 16#4969_474D#, 16#3E6E_77DB#,
+      16#AED1_6A4A#, 16#D9D6_5ADC#, 16#40DF_0B66#, 16#37D8_3BF0#,
+      16#A9BC_AE53#, 16#DEBB_9EC5#, 16#47B2_CF7F#, 16#30B5_FFE9#,
+      16#BDBD_F21C#, 16#CABA_C28A#, 16#53B3_9330#, 16#24B4_A3A6#,
+      16#BAD0_3605#, 16#CDD7_0693#, 16#54DE_5729#, 16#23D9_67BF#,
+      16#B366_7A2E#, 16#C461_4AB8#, 16#5D68_1B02#, 16#2A6F_2B94#,
+      16#B40B_BE37#, 16#C30C_8EA1#, 16#5A05_DF1B#, 16#2D02_EF8D#);
+
+   ---------------
+   -- Get_Value --
+   ---------------
+
+   function Get_Value (C : CRC32) return Interfaces.Unsigned_32 is
+   begin
+      return Interfaces.Unsigned_32 (C xor XorOut);
+   end Get_Value;
+
+   ----------------
+   -- Initialize --
+   ----------------
+
+   procedure Initialize (C : out CRC32) is
+   begin
+      C := Init;
+   end Initialize;
+
+   ------------
+   -- Update --
+   ------------
+
+   procedure Update (C : in out CRC32; Value : Character) is
+      V : constant CRC32 := CRC32 (Character'Pos (Value));
+
+   begin
+      C := Shift_Right (C, 8) xor Table (V xor (C and 16#0000_00FF#));
+   end Update;
+
+end System.CRC32;
diff --git a/gcc/ada/s-crc32.ads b/gcc/ada/s-crc32.ads
new file mode 100644
index 0000000..07ad1b5
--- /dev/null
+++ b/gcc/ada/s-crc32.ads
@@ -0,0 +1,84 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT LIBRARY COMPONENTS                          --
+--                                                                          --
+--                        S Y S T E M  . C R C 3 2                          --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--                            $Revision$
+--                                                                          --
+--              Copyright (C) 2001 Ada Core Technologies, 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 2,  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 COPYING.  If not, write --
+-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
+-- MA 02111-1307, USA.                                                      --
+--                                                                          --
+-- As a special exception,  if other files  instantiate  generics from this --
+-- unit, or you link  this unit with other files  to produce an executable, --
+-- this  unit  does not  by itself cause  the resulting  executable  to  be --
+-- covered  by the  GNU  General  Public  License.  This exception does not --
+-- however invalidate  any other reasons why  the executable file  might be --
+-- covered by the  GNU Public License.                                      --
+--                                                                          --
+-- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com).   --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  This package provides routines for computing a commonly used checksum
+--  called CRC-32. This is a checksum based on treating the binary data
+--  as a polynomial over a binary field, and the exact specifications of
+--  the CRC-32 algorithm are as follows:
+--
+--     Name   : "CRC-32"
+--     Width  : 32
+--     Poly   : 04C11DB7
+--     Init   : FFFFFFFF
+--     RefIn  : True
+--     RefOut : True
+--     XorOut : FFFFFFFF
+--     Check  : CBF43926
+--
+--  Note that this is the algorithm used by PKZip, Ethernet and FDDI.
+--
+--  For more information about this algorithm see:
+--
+--  ftp://ftp.rocksoft.com/papers/crc_v3.txt
+
+--  "A Painless Guide to CRC Error Detection Algorithms", Ross N. Williams
+--
+--  "Computation of Cyclic Redundancy Checks via Table Look-Up", Communications
+--  of the ACM, Vol. 31 No. 8, pp.1008-1013 Aug. 1988. Sarwate, D.V.
+
+with Interfaces;
+
+package System.CRC32 is
+
+   type CRC32 is new Interfaces.Unsigned_32;
+   --  Used to represent CRC32 values, which are 32 bit bit-strings
+
+   procedure Initialize (C : out CRC32);
+   pragma Inline (Initialize);
+   --  Initialize CRC value by assigning the standard Init value (16#FFFF_FFFF)
+
+   procedure Update
+     (C     : in out CRC32;
+      Value : Character);
+   pragma Inline (Update);
+   --  Evolve CRC by including the contribution from Character'Pos (Value)
+
+   function Get_Value (C : CRC32) return Interfaces.Unsigned_32;
+   pragma Inline (Get_Value);
+   --  Get_Value computes the CRC32 value by performing an XOR with the
+   --  standard XorOut value (16#FFFF_FFFF). Note that this does not
+   --  change the value of C, so it may be used to retrieve intermediate
+   --  values of the CRC32 value during a sequence of Update calls.
+
+end System.CRC32;
diff --git a/gcc/ada/scans.ads b/gcc/ada/scans.ads
index b9d89e1..a68cbbf 100644
--- a/gcc/ada/scans.ads
+++ b/gcc/ada/scans.ads
@@ -6,9 +6,9 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---                            $Revision: 1.32 $
+--                            $Revision$
 --                                                                          --
---          Copyright (C) 1992-2000 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- --
@@ -34,6 +34,7 @@
 ------------------------------------------------------------------------------
 
 with Types; use Types;
+
 package Scans is
 
 --  The scanner maintains a current state in the global variables defined
@@ -342,8 +343,8 @@ package Scans is
    --  recovery circuits which depend on looking at the column line up.
 
    Checksum : Word;
-   --  Used to accumulate a checksum representing the tokens in the source
-   --  file being compiled. This checksum includes only program tokens, and
+   --  Used to accumulate a CRC representing the tokens in the source
+   --  file being compiled. This CRC includes only program tokens, and
    --  excludes comments.
 
    First_Non_Blank_Location : Source_Ptr;
diff --git a/gcc/ada/scn-nlit.adb b/gcc/ada/scn-nlit.adb
index f027ba2..d1fc9ea 100644
--- a/gcc/ada/scn-nlit.adb
+++ b/gcc/ada/scn-nlit.adb
@@ -6,9 +6,9 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.32 $                             --
+--                            $Revision$                             --
 --                                                                          --
---   Copyright (C) 1992,1993,1994,1995,1996 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- --
diff --git a/gcc/ada/scn-slit.adb b/gcc/ada/scn-slit.adb
index 508d5c2..b60ffc2 100644
--- a/gcc/ada/scn-slit.adb
+++ b/gcc/ada/scn-slit.adb
@@ -6,9 +6,9 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.29 $                             --
+--                            $Revision$
 --                                                                          --
---          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- --
diff --git a/gcc/ada/scn.adb b/gcc/ada/scn.adb
index 146314d..af6668a 100644
--- a/gcc/ada/scn.adb
+++ b/gcc/ada/scn.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.111 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -39,6 +39,7 @@ with Snames;   use Snames;
 with Style;
 with Widechar; use Widechar;
 
+with System.CRC32;
 with System.WCh_Con; use System.WCh_Con;
 
 package body Scn is
@@ -73,6 +74,10 @@ package body Scn is
    --  are scanned. We use the character code rather than the ASCII characters
    --  so that the checksum is independent of wide character encoding method.
 
+   procedure Initialize_Checksum;
+   pragma Inline (Initialize_Checksum);
+   --  Initialize checksum value
+
    procedure Check_End_Of_Line;
    --  Called when end of line encountered. Checks that line is not
    --  too long, and that other style checks for the end of line are met.
@@ -135,20 +140,13 @@ package body Scn is
 
    procedure Accumulate_Checksum (C : Character) is
    begin
-      Checksum := Checksum + Checksum + Character'Pos (C);
-
-      if Checksum > 16#8000_0000# then
-         Checksum := (Checksum + 1) and 16#7FFF_FFFF#;
-      end if;
+      System.CRC32.Update (System.CRC32.CRC32 (Checksum), C);
    end Accumulate_Checksum;
 
    procedure Accumulate_Checksum (C : Char_Code) is
    begin
-      Checksum := Checksum + Checksum + Char_Code'Pos (C);
-
-      if Checksum > 16#8000_0000# then
-         Checksum := (Checksum + 1) and 16#7FFF_FFFF#;
-      end if;
+      Accumulate_Checksum (Character'Val (C / 256));
+      Accumulate_Checksum (Character'Val (C mod 256));
    end Accumulate_Checksum;
 
    -----------------------
@@ -367,6 +365,15 @@ package body Scn is
       Error_Msg_S ("two consecutive underlines not permitted");
    end Error_No_Double_Underline;
 
+   -------------------------
+   -- Initialize_Checksum --
+   -------------------------
+
+   procedure Initialize_Checksum is
+   begin
+      System.CRC32.Initialize (System.CRC32.CRC32 (Checksum));
+   end Initialize_Checksum;
+
    ------------------------
    -- Initialize_Scanner --
    ------------------------
@@ -465,7 +472,8 @@ package body Scn is
       Token_Name                := No_Name;
       Start_Column              := Set_Start_Column;
       First_Non_Blank_Location  := Scan_Ptr;
-      Checksum                  := 0;
+
+      Initialize_Checksum;
 
       --  Set default for Comes_From_Source. All nodes built now until we
       --  reenter the analyzer will have Comes_From_Source set to True
diff --git a/gcc/ada/sinput.ads b/gcc/ada/sinput.ads
index 585a8b9..b842790 100644
--- a/gcc/ada/sinput.ads
+++ b/gcc/ada/sinput.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---                            $Revision: 1.69 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -274,34 +274,18 @@ package Sinput is
    --  minus-minus sequence starting a comment, and all control characters
    --  except ESC.
 
-   --  These characters are used to compute a 31-bit checksum which is stored
-   --  in the variable Scans.Checksum, as follows:
-
-   --    If a character, C, is not part of a wide character sequence, then
-   --    either the character itself, or its lower case equivalent if it
-   --    is a letter outside a string literal is used in the computation:
-
-   --      Checksum := Checksum + Checksum + Character'Pos (C);
-   --      if Checksum > 16#8000_0000# then
-   --         Checksum := (Checksum + 1) and 16#7FFF_FFFF#;
-   --      end if;
-
-   --    For a wide character sequence, the checksum is computed using the
-   --    corresponding character code value C, as follows:
-
-   --      Checksum := Checksum + Checksum + Char_Code'Pos (C);
-   --      if Checksum > 16#8000_0000# then
-   --         Checksum := (Checksum + 1) and 16#7FFF_FFFF#;
-   --      end if;
+   --  The checksum algorithm used is the standard CRC-32 algorithm, as
+   --  implemented by System.CRC32, except that we do not bother with the
+   --  final XOR with all 1 bits.
 
    --  This algorithm ensures that the checksum includes all semantically
    --  significant aspects of the program represented by the source file,
    --  but is insensitive to layout, presence or contents of comments, wide
    --  character representation method, or casing conventions outside strings.
 
-   --  Scans.Checksum is initialized to zero at the start of scanning a file,
-   --  and copied into the Source_Checksum field of the file table entry when
-   --  the end of file is encountered.
+   --  Scans.Checksum is initialized appropriately at the start of scanning
+   --  a file, and copied into the Source_Checksum field of the file table
+   --  entry when the end of file is encountered.
 
    -------------------------------------
    -- Handling Generic Instantiations --
diff --git a/gcc/ada/types.adb b/gcc/ada/types.adb
index 0c668a5..2ab0c5b 100644
--- a/gcc/ada/types.adb
+++ b/gcc/ada/types.adb
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                            $Revision: 1.20 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -140,7 +140,7 @@ package body Types is
    --------------------
 
    subtype Wordh is Word range 0 .. 15;
-   Hex : constant array (Wordh) of Character := "0123456789ABCDEF";
+   Hex : constant array (Wordh) of Character := "0123456789abcdef";
 
    function Get_Hex_String (W : Word) return Word_Hex_String is
       X  : Word := W;
diff --git a/gcc/ada/types.ads b/gcc/ada/types.ads
index 1cbf57d..77b2219 100644
--- a/gcc/ada/types.ads
+++ b/gcc/ada/types.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---                            $Revision: 1.87 $
+--                            $Revision$
 --                                                                          --
 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
 --                                                                          --
@@ -121,7 +121,7 @@ pragma Preelaborate (Types);
    --  Procedure for freeing dynamically allocated String values
 
    subtype Word_Hex_String is String (1 .. 8);
-   --  Type used to represent Word value as 8 hex digits, with upper case
+   --  Type used to represent Word value as 8 hex digits, with lower case
    --  letters for the alphabetic cases.
 
    function Get_Hex_String (W : Word) return Word_Hex_String;