Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.jpl.nasa.gov (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: yacc stack overflow
Message-ID: <1991Mar14.042103.26095@jpl-devvax.jpl.nasa.gov>
Date: 14 Mar 91 04:21:03 GMT
References: <EMV.91Mar8010709@poe.aa.ox.com> <1991Mar13.012932.1710@NCoast.ORG> <1991Mar13.234823.12036@NCoast.ORG>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 100

In article <1991Mar13.234823.12036@NCoast.ORG> allbery@ncoast.ORG (Brandon S. Allbery KB8JRR) writes:
: As quoted from <1991Mar13.012932.1710@NCoast.ORG> by allbery@NCoast.ORG (Brandon S. Allbery KB8JRR):
: +---------------
: | /usr/lib/yaccpar and I produce a modified version that dynamically allocates
: | yacc stack space, can I post the diffs without getting AT&T on my case?
: +---------------
: 
: Actually, the answer *may* be "yes" --- AT&T has already permitted generated
: y.tab.c's to be distributed.
: 
: In any case, I got two main suggestions:  byacc (which is freely hackable) and
: bison (which automatically grows the stack).  In my case, bison is out:  I
: had the same problem with some home-grown parsers... which must be linked with
: proprietary libraries.  And I've explained to a brick wall (read: rms) why
: that can't change.
: 
: I *have* byacc, so that's an idea.  But many people don't have it, and do have
: Perl, and therefore have a problem.  Suggestions?

Find the line in your Makefile that says "mv y.tab.c ..." and change
the mv to perly.fixer.  Install the following script as perly.fixer.
See if it helps.  :-)

I note that Sun's yaccpar already does dynamic stack allocation.  This
script is built to fix 4.3BSD's yaccpar--lemme know if yours differs.

I don't like arbitrary limits either...

Larry

#!/bin/sh
: make a subdirectory, cd to it, and run this through sh.
echo 'If this kit is complete, "End of kit" will echo at the end'
echo Extracting perly.fixer
sed >perly.fixer <<'!STUFFY!FUNK!' -e 's/X//'
X#!/bin/sh
X
Xinput=$1
Xoutput=$2
Xtmp=/tmp/f$$
X
Xegrep 'YYSTYPE[ 	]*yyv\[ *YYMAXDEPTH *\];
Xshort[ 	]*yys\[ *YYMAXDEPTH *\] *;
Xyyps *= *&yys\[ *-1 *\];
Xyypv *= *&yyv\[ *-1 *\];
Xif *\( *\+\+yyps *> *&yys\[ *YYMAXDEPTH *\] *\)' $input >$tmp
Xset `wc -l $tmp`
X
Xcase "$1" in
X5) echo "Patching perly.c to allow dynamic yacc stack allocation";;
X*) mv $input $output; rm -f $tmp; exit;;
Xesac
X
Xcat >$tmp <<'END'
X/YYSTYPE[ 	]*yyv\[ *YYMAXDEPTH *\];/c\
Xint yymaxdepth = YYMAXDEPTH;\
XYYSTYPE *yyv; /* where the values are stored */\
Xshort *yys;\
Xshort *maxyyps;
X
X/short[ 	]*yys\[ *YYMAXDEPTH *\] *;/d
X
X/yyps *= *&yys\[ *-1 *\];/d
X
X/yypv *= *&yyv\[ *-1 *\];/c\
X\	if (!yyv) {\
X\	    yyv = (YYSTYPE*) malloc(yymaxdepth * sizeof(YYSTYPE));\
X\	    yys = (short*) malloc(yymaxdepth * sizeof(short));\
X\	    maxyyps = &yys[yymaxdepth];\
X\	}\
X\	yyps = &yys[-1];\
X\	yypv = &yyv[-1];
X
X
X/if *( *\+\+yyps *> *&yys\[ *YYMAXDEPTH *\] *)/c\
X\		if( ++yyps >= maxyyps ) {\
X\		    int tv = yypv - yyv;\
X\		    int ts = yyps - yys;\
X\
X\		    yymaxdepth *= 2;\
X\		    yyv = (YYSTYPE*)realloc((char*)yyv,\
X\		      yymaxdepth*sizeof(YYSTYPE));\
X\		    yys = (short*)realloc((char*)yys,\
X\		      yymaxdepth*sizeof(short));\
X\		    yyps = yys + ts;\
X\		    yypv = yyv + tv;\
X\		    maxyyps = &yys[yymaxdepth];\
X\		}
X
X/yacc stack overflow.*}/d
X/yacc stack overflow/,/}/d
XEND
X
Xsed -f $tmp <$input >$output
Xrm -rf $tmp $input
!STUFFY!FUNK!
echo ""
echo "End of kit"
: I do not append .signature, but someone might mail this.
exit