Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!sun-barr!male!pitstop!sun!news
From: news@sun.Eng.Sun.COM (news)
Newsgroups: gnu.gcc.bug
Subject: Re: Feedback on gcc 1.35 -- Sun 3 and 386i SunOS4.0.1
Summary: It *is* a timestamp
Keywords: COFF timestamp
Message-ID: <102323@sun.Eng.Sun.COM>
Date: 2 May 89 03:16:30 GMT
References: <12490025278.16.BEEBE@SCIENCE.UTAH.EDU>
Reply-To: bitbug (James Buster)
Distribution: gnu
Organization: Sun Microsystems, Inc.
Lines: 40

In article <12490025278.16.BEEBE@SCIENCE.UTAH.EDU> Beebe@SCIENCE.UTAH.EDU ("Nelson H.F. Beebe") writes:
>========================================================================
>SUGGESTION: Since the stage[12] regression test is very reassuring, I
>like to run it during installation of each version of gcc (which I've
>done about 20 times now).  It would be nice if there were a make target
>to do it automatically.  On Sun 386i systems, there appears to be a time
>stamp in the .o files which makes all the cmp's fail.  I get around the
>problem with this little script (which could be put in the Makefile,
>with suitable adjustment of the cmp offsets):

What you see is in fact a timestamp. The Sun 386i uses COFF format
object files. From /usr/include/filehdr.h:

struct filehdr {
	unsigned short	f_magic;	/* magic number */
	unsigned short	f_nscns;	/* number of sections */
NOTE ->	long		f_timdat;	/* time & date stamp */
	long		f_symptr;	/* file pointer to symtab */
	long		f_nsyms;	/* number of symtab entries */
	unsigned short	f_opthdr;	/* sizeof(optional hdr) */
	unsigned short	f_flags;	/* flags */
};

># .o files have uniform difference in bytes at offsets 4,5;
># start comparisons beyond that;  bug-gnu-gcc suggests it may be a 
># timestamp
>echo "Begin .o file comparisons -- any output indicates ERRORS"
>foreach file (*.o)
>	cmp $file stage2/$file 6 6
>end

Given the structure definition above, you should start the comparisons
at offset 8 rather than 6:
	2 byte short + 2 byte short + 4 byte timestamp == 8 bytes to ignore.

--------------------------------------------
	     James Buster
	Mad Hacker Extraordinaire
	 bitbug@lonewolf.sun.com
--------------------------------------------