mercury/tools/binary

#!/bin/sh
#
# vim: ts=4 sw=4 et
#
# This script finds miscompiled procedures.
#
# Given a stage2 directory that works (stage2.ok) and one that doesn't
# (stage2.bad), both of which must have their object files, this script
# uses binary search to try to find in stage2.bad first the C source file
# and then the module within that C source file that, when put together
# with everything else from the stage2.ok directory, still causes the
# compiler to fail.
#
# If the bad C source file has different numbers of modules in the bad and ok
# versions, then the script stops after identifying only the file.
#
# The test for the composite stage2 compiler is either bootstrap checking
# (the default), some initial part of bootstrap checking (making dependencies,
# compiling the library), the successful execution of all the test cases in
# one or more subdirectories of the tests directory, or the successful execution
# of a single command.

usage="\
Usage: $0 [options]
Options:
    -b-, --no-bootcheck
        Do not perform a bootcheck; check only the tests directory
        or the single command.
    -c, --compile-only
        Check the successful creation of the stage3 .c files,
        but do not compare stage2.ok and stage3.
    -C, --compare-to-bad
        Compile stage3 using the parameter settings in the stage2.bad
        directory, and compare stage3 to stage2.bad, not stage2.ok.
    -d, --dependency-only
        Make dependencies for stage3 only. Do not compile stage3.
    -D <dirname>, --dir <dirname>
        Confine the search to one directory, library, mdbcomp, browser
        or compiler. (Usually useful only after a previous search.)
    -f <modulename>, --file <modulename>
        Confine the search to the named file(s).
        (Usually useful only after a previous search.)
    -G <grade>, --grade <grade>
        Specify the grade to test.
    -h, --help
        Display this usage message.
    -j <num-jobs>, --jobs <num-jobs>
        Run using <num-jobs> different parallel processes.
    -l, --library-only
        Check the successful creation of the stage3 .c files in the
        library, but do not compile the compiler directory.
    -m <mmake-args>, --mmake-args <mmake-args>
        Pass <mmake-args> as options to \`mmake'.
    -n, --negative-search
        Look for the module that suppresses the bug, not causes it.
    -o <filename>, --output-file <filename>
        Output results to <filename>.
    -r, --copy-runtime
        Copy the runtime directory instead of linking it.
        This is necessary if the test uses a compilation model option
        that differs from the one used in the main runtime directory.
    -s <command>, --single-command <command>
        Execute the given command using each constructed compiler.
    -t <testdir>, --test-dir <testdir>
        Execute runtests from the named subdirectory of tests.
"

# If you change this, you will also need to change the files indicated
# in scripts/c2init.in.
STD_LIB_NAME=mer_std

set -x

bootcheck=""
compile_only=""
dependency_only=""
grade=""
library_only=""
jfactor=
mmake_opts=""
outfile=""
copy_runtime=false
single_command=""
testdirs=""
negative=false
alldirs=""
allmodules=""
compare_to_bad=""
basis="ok"

while [ $# -gt 0 ]; do
    case "$1" in

    -b-|--no-bootcheck)
        bootcheck="-b-" ;;

    -c|--compile-only)
        compile_only="-c" ;;

    -C|--compare-to-bad)
        compare_to_bad="-C"
        basis="bad" ;;

    -d|--dependency-only)
        dependency_only="-d" ;;

    -D|--dir)
        if test "$alldirs" = ""
        then
            alldirs="$2"; shift
        else
            echo "You can specify only one directory." 1>&2
            exit 1
        fi
        ;;
    -D*)
        if test "$alldirs" = ""
        then
            alldirs="` expr $1 : '-d\(.*\)' `"
        else
            echo "You can specify only one directory." 1>&2
            exit 1
        fi
        ;;

    -f|--file)
        allmodules="$allmodules $2"; shift ;;
    -f*)
        allmodules="$allmodules ` expr $1 : '-f\(.*\)' `"; ;;

    -G|--grade)
        grade="$2"; shift ;;
    -G*)
        grade="` expr X$1 : 'X-G\(.*\)' `"; ;;

    -h|--help)
        echo "$usage"
        exit 0 ;;

    -j|--jobs)
        jfactor="-j$2"; shift ;;
    -j*)
        jfactor="-j` expr $1 : '-j\(.*\)' `" ;;
    --jobs*)
        jfactor="--jobs` expr $1 : '--jobs\(.*\)' `" ;;

    -l|--library-only)
        library_only="-l" ;;

    -m|--mmake)
        mmake_opts="$mmake_opts $2"; shift ;;

    -n|--negative-search)
        negative=true ;;

    -o|--output-file)
        outfile="-o $2"; shift ;;
    -o*)
        outfile="-o ` expr $1 : '-o\(.*\)' `"; ;;

    -r|--copy-runtime)
        copy_runtime=true ;;

    -s|--single-command)
        single_command="$2"; shift ;;
    -s*)
        single_command=` expr "$1" : '-s\(.*\)' ` ;;
    --single-command*)
        single_command=` expr "$1" : '--single-command\(.*\)' ` ;;

    -t|--test-dir)
        testdirs="$testdirs -t$2"; shift ;;
    -t*)
        testdirs="$testdirs ` expr $1 : '-t\(.*\)' `" ;;

    -*)
        echo "$0: unknown option \`$1'" 1>&2
        echo "$usage" 1>&2
        exit 1 ;;

    *)
        echo "$usage" 1>&2
        exit 1 ;;
    esac
    shift
done

if test "${grade}" != ""
then
    grade_opt="--grade ${grade}"
    mmake_grade_opt="GRADE=${grade}"
else
    grade_opt=""
    mmake_grade_opt=""
fi

if "$negative"
then
    base=bad
    trial=ok
    expected=failure
else
    base=ok
    trial=bad
    expected=success
fi

if test -d stage2.ok -a -d stage2.bad
then
    echo "stage2.ok and stage2.bad both present"
else
    echo "at least one of stage2.ok and stage2.bad is missing"
    exit 1
fi

root=`/bin/pwd`
trueroot=`echo $root | sed '
s:/mount/munkora/mercury:/home/mercury:
s:/mount/munkora/home/mercury:/home/mercury:
s:/mount/munkora/clp/mercury:/home/mercury:'`
PATH=$root/tools:$PATH
export PATH

if test "$RMSTAGECMD" = ""
then
    RMSTAGECMD="/bin/rm -fr"
fi

echo "starting at `date`"

possibly_suspect_dirs="library mdbcomp browser compiler"

for dir in $base $trial
do
    for subdir in ${possibly_suspect_dirs}
    do
        case $subdir in
            library)    example=builtin ;;
            mdbcomp)    example=mdbcomp.prim_data ;;
            browser)    example=mdb.declarative_edt ;;
            compiler)   example=check_hlds.cse_detection ;;
        esac

        ( cd stage2.$dir/$subdir; gunzip *.gz )

        if test -f stage2.$dir/$subdir/${example}.o
        then
            echo "stage2.$dir/$subdir seems to have its .o files"
        else
            echo "reconstructing object files in stage2.$dir/$subdir"
            ( cd stage2.$dir/$subdir; mmake ${mmake_grade_opt} )
        fi
    done
done

echo "starting binary at `date`"

set +x
[ -d stage2 ] || mkdir stage2
$RMSTAGECMD $trueroot/stage2/compiler < /dev/null &
$RMSTAGECMD $trueroot/stage2/library < /dev/null &
wait
$RMSTAGECMD $trueroot/stage2/* < /dev/null
echo linking stage 2... 1>&2
cd stage2
mkdir compiler
cd compiler
ln -s $root/compiler/[a-h]*.m .
ln -s $root/compiler/[i-o]*.m .
ln -s $root/compiler/[p-s]*.m .
ln -s $root/compiler/[t-z]*.m .
cp $root/compiler/Mmake* .
cp $root/compiler/Mercury* .
cp $root/compiler/*FLAGS* .
cp $root/compiler/.mgnuc* .
cd $root/stage2
mkdir library
cd library
ln -s $root/library/[a-l]*.m .
ln -s $root/library/[m-z]*.m .
ln -s $root/library/*.init .
cp $root/library/print_extra_inits .
cp $root/library/MODULES_DOC .
cp $root/library/MODULES_UNDOC .
cp $root/library/Mmake* .
cp $root/library/Mercury* .
cp $root/library/*FLAGS* .
cp $root/library/MODULES* .
cp $root/library/mer_std.trans_opt_deps_spec .
cp $root/library/.mgnuc* .
cd $root/stage2
mkdir mdbcomp
cd mdbcomp
ln -s $root/mdbcomp/*.m .
ln -s $root/mdbcomp/*.init .
cp $root/mdbcomp/Mmake* .
cp $root/mdbcomp/Mercury* .
cp $root/mdbcomp/*FLAGS* .
cp $root/mdbcomp/.mgnuc* .
cd $root/stage2
mkdir browser
cd browser
ln -s $root/browser/*.m .
ln -s $root/browser/*.init .
cp $root/browser/Mmake* .
cp $root/browser/Mercury* .
cp $root/browser/*FLAGS* .
cp $root/browser/.mgnuc* .
cd $root/stage2
if "$copy_runtime"
then
    mkdir runtime
    cd runtime
    ln -s $root/runtime/*.h .
    ln -s $root/runtime/*.c .
    ln -s $root/runtime/*.in .
    ln -s $root/runtime/machdeps .
    cp $root/runtime/Mmake* .
    cd $root/stage2
else
    # $root/runtime may be in a different grade from the stage2 directories.
    ln -s $root/stage2.ok/runtime .
fi
ln -s $root/boehm_gc .
ln -s $root/ssdb .
ln -s $root/trace .
ln -s $root/robdd .
ln -s $root/doc .
ln -s $root/scripts .
ln -s $root/util .
ln -s $root/profiler .
ln -s $root/deep_profiler .
ln -s $root/tools .
ln -s $root/conf* .
ln -s $root/aclocal.m4 .
ln -s $root/VERSION .
ln -s $root/Mercury.options .
ln -s $root/.*.in .
rm -f config*.log
cp $root/stage2.ok/Mmake* .
cd $root

# We don't copy the .d files. This prevents mmake from trying to remake any
# of the .c and .o files, which we provide in the form they should be used.

# cp stage2.ok/library/*.d stage2/library
cp stage2.ok/library/*.dep stage2/library
cp stage2.ok/library/*.dv stage2/library
cp stage2.ok/library/*.int0 stage2/library
cp stage2.ok/library/*.int3 stage2/library
cp stage2.ok/library/*.date0 stage2/library
cp stage2.ok/library/*.date3 stage2/library
cp stage2.ok/library/*.int stage2/library
cp stage2.ok/library/*.int2 stage2/library
cp stage2.ok/library/*.date stage2/library
cp stage2.ok/library/*.opt stage2/library
cp stage2.ok/library/*.optdate stage2/library
cp stage2.ok/library/*.trans_opt stage2/library
cp stage2.ok/library/*.trans_opt_date stage2/library
cp stage2.ok/library/*.mh stage2/library
cp stage2.ok/library/*.mih stage2/library
# cp stage2.ok/mdbcomp/*.d stage2/mdbcomp
cp stage2.ok/mdbcomp/*.dep stage2/mdbcomp
cp stage2.ok/mdbcomp/*.dv stage2/mdbcomp
cp stage2.ok/mdbcomp/*.int0 stage2/mdbcomp
cp stage2.ok/mdbcomp/*.int3 stage2/mdbcomp
cp stage2.ok/mdbcomp/*.date0 stage2/mdbcomp
cp stage2.ok/mdbcomp/*.date3 stage2/mdbcomp
cp stage2.ok/mdbcomp/*.int stage2/mdbcomp
cp stage2.ok/mdbcomp/*.int2 stage2/mdbcomp
cp stage2.ok/mdbcomp/*.date stage2/mdbcomp
cp stage2.ok/mdbcomp/*.mh stage2/mdbcomp
cp stage2.ok/mdbcomp/*.mih stage2/mdbcomp
# cp stage2.ok/browser/*.d stage2/browser
cp stage2.ok/browser/*.dep stage2/browser
cp stage2.ok/browser/*.dv stage2/browser
cp stage2.ok/browser/*.int0 stage2/browser
cp stage2.ok/browser/*.int3 stage2/browser
cp stage2.ok/browser/*.date0 stage2/browser
cp stage2.ok/browser/*.date3 stage2/browser
cp stage2.ok/browser/*.int stage2/browser
cp stage2.ok/browser/*.int2 stage2/browser
cp stage2.ok/browser/*.date stage2/browser
cp stage2.ok/browser/*.mh stage2/browser
cp stage2.ok/browser/*.mih stage2/browser
# cp stage2.ok/compiler/*.d stage2/compiler
cp stage2.ok/compiler/*.dep stage2/compiler
cp stage2.ok/compiler/*.dv stage2/compiler
cp stage2.ok/compiler/*.int0 stage2/compiler
cp stage2.ok/compiler/*.int3 stage2/compiler
cp stage2.ok/compiler/*.date0 stage2/compiler
cp stage2.ok/compiler/*.date3 stage2/compiler
cp stage2.ok/compiler/*.int stage2/compiler
cp stage2.ok/compiler/*.int2 stage2/compiler
cp stage2.ok/compiler/*.date stage2/compiler
cp stage2.ok/compiler/*.mh stage2/compiler
cp stage2.ok/compiler/*.mih stage2/compiler

if test "$bootcheck" = ""
then
    cd $root
    [ -d stage3 ] || mkdir stage3
    $RMSTAGECMD $trueroot/stage3/compiler < /dev/null &
    $RMSTAGECMD $trueroot/stage3/library < /dev/null &
    wait
    $RMSTAGECMD $trueroot/stage3/* < /dev/null
    echo linking stage 3... 1>&2

    cd stage3
    mkdir compiler
    cd compiler
    # Break up the links into several chunks.
    # This is needed to cope with small limits
    # on the size of argument vectors.
    ln -s $root/compiler/[a-h]*.m .
    ln -s $root/compiler/[i-o]*.m .
    ln -s $root/compiler/[p-s]*.m .
    ln -s $root/compiler/[t-z]*.m .
    cp $root/compiler/Mmake* .
    cp $root/compiler/Mercury* .
    cp $root/compiler/*FLAGS* .
    cp $root/compiler/.mgnuc* .

    cd $root/stage3
    mkdir library
    cd library
    ln -s $root/library/[a-l]*.m .
    ln -s $root/library/[m-z]*.m .
    ln -s $root/library/*.init .
    cp $root/library/Mmake* .
    cp $root/library/Mercury* .
    cp $root/library/*FLAGS* .
    cp $root/library/MODULES* .
    cp $root/library/mer_std.trans_opt_deps_spec .
    cp $root/library/.mgnuc* .

    cd $root/stage3
    mkdir mdbcomp
    cd mdbcomp
    ln -s $root/mdbcomp/*.m .
    ln -s $root/mdbcomp/*.init .
    cp $root/mdbcomp/Mmake* .
    cp $root/mdbcomp/Mercury* .
    cp $root/mdbcomp/*FLAGS* .
    cp $root/mdbcomp/.mgnuc* .

    cd $root/stage3
    mkdir browser
    cd browser
    ln -s $root/browser/*.m .
    ln -s $root/browser/*.init .
    cp $root/browser/Mmake* .
    cp $root/browser/Mercury* .
    cp $root/browser/*FLAGS* .
    cp $root/browser/.mgnuc* .

    cd $root/stage3
    ln -s $root/boehm_gc .
    ln -s $root/ssdb .
    ln -s $root/trace .
    ln -s $root/doc .
    ln -s $root/scripts .
    ln -s $root/util .
    ln -s $root/profiler .
    ln -s $root/deep_profiler .
    ln -s $root/runtime .
    ln -s $root/tools .
    ln -s $root/conf* .
    ln -s $root/aclocal.m4 .
    ln -s $root/VERSION .
    ln -s $root/Mercury.options .
    ln -s $root/.*.in .
    rm -f config*.log
    /bin/rm -f Mmake*
    cp $root/stage2.$basis/Mmake* .
    # cp $root/stage2.ok/so_locations .
    cd $root
fi

if "$copy_runtime"
then
    if (cd stage2 ; mmake $mmake_grade_opt $mmake_opts $jfactor runtime)
    then
        echo "building of stage 2 runtime successful"
    else
        echo "building of stage 2 runtime not successful"
        exit 1
    fi
fi

if test "$alldirs" = ""
then
    echo testing which directory the problem is in

    /bin/rm .stage2_problem > /dev/null 2>&1
    found=false
    for testsubdir in library mdbcomp compiler
    do
        if $found
        then
            echo skipping test of $testsubdir
        else
            testsubdir_modules=`ls stage2.ok/$testsubdir`
            anydiff=false
            for testsubdir_module in $testsubdir_modules
            do
                if cmp -s stage2.{bad,ok}/$testsubdir/$testsubdir_module
                then
                    true
                else
                    anydiff=true
                fi
            done

            if $anydiff
            then
                echo testing whether the problem is in $testsubdir

                for subdir in ${possibly_suspect_dirs}
                do
                    if test "$subdir" = "$testsubdir"
                    then
                        echo copying stage2/$subdir from stage2.bad/$subdir \
                            1>&2
                        cp stage2.bad/$subdir/*.[co] stage2/$subdir
                        cp stage2.bad/$subdir/*.pic_o stage2/$subdir \
                            > /dev/null 2>&1
                    else
                        echo copying stage2/$subdir from stage2.ok/$subdir \
                            1>&2
                        cp stage2.ok/$subdir/*.[co] stage2/$subdir
                        cp stage2.ok/$subdir/*.pic_o stage2/$subdir \
                            > /dev/null 2>&1
                    fi
                done

                binary_step $bootcheck $compile_only $compare_to_bad \
                    $dependency_only $library_only $jfactor $grade_opt \
                    -m "$mmake_opts" $outfile $testdirs -s "$single_command"
                step_status=$?

                if test -f .stage2_problem
                then
                    echo could not build stage 2 to test
                    exit 1
                fi

                if "$negative"
                then
                    if test "$step_status" == 0
                    then
                        testeddir=$testsubdir
                        found=true
                        echo "solution seems to be in the $testeddir directory"
                    fi
                else
                    if test "$step_status" != 0
                    then
                        testeddir=$testsubdir
                        found=true
                        echo "problem seems to be in the $testeddir directory"
                    fi
                fi
            else
                echo skipping $testsubdir: the two stage2s match
            fi
        fi
    done

    if test "$found" = false
    then
        echo "could not find problem"
        exit 1
    fi
else
    for subdir in ${possibly_suspect_dirs}
    do
        echo linking stage2/$subdir from stage2.ok/$subdir 1>&2
        cp stage2.ok/$subdir/*.[co] stage2/$subdir
        cp stage2.ok/$subdir/*.pic_o stage2/$subdir > /dev/null 2>&1
    done

    testeddir=$alldirs
    if test ! -d stage2/$testeddir
    then
        echo $stage2/$testeddir does not exist
        exit 1
    fi
fi

# start out with all files in stage2 coming from stage2.$base

set +x
echo linking stage2 from stage2.$base 1>&2
cp stage2.$base/library/*.{c,o,pic_o} stage2/library
cp stage2.$base/mdbcomp/*.{c,o,pic_o} stage2/mdbcomp
cp stage2.$base/browser/*.{c,o,pic_o} stage2/browser
cp stage2.$base/compiler/*.{c,o} stage2/compiler
set -x

# find the set of candidate modules

if test "$allmodules" = ""
then
    cd stage2/$testeddir
    for module in *.c
    do
        if cmp -s $root/stage2.{bad,ok}/$testeddir/$module.c
        then
            true
        else
            allmodules="$allmodules `basename $module .c`"
        fi
    done
    cd $root
else
    for module in $allmodules
    do
        if test ! -f stage2/$testeddir/$module.c
        then
            echo $stage2/$testeddir/$module.c does not exist
            exit 1
        fi
    done
fi

doubtful="$allmodules"
tested=`half $doubtful`
knowngood=

while test "$tested" != ""
do
    # at this point, all the files in stage2 should be from stage2.$base

    echo "doubtful modules: $doubtful"
    echo "testing modules:  $tested"

    for module in $tested
    do
        cp stage2.$trial/$testeddir/$module.[co] stage2/$testeddir
        case "${testeddir}" in
            library|mdbcomp|browser)
                cp stage2.$trial/${testeddir}/$module.pic_o stage2/${testeddir}
                ;;
        esac
    done

    if "$negative"
    then
        if binary_step $bootcheck $compile_only $compare_to_bad \
            $dependency_only $library_only $jfactor $grade_opt \
            -m "$mmake_opts" $outfile $testdirs -s "$single_command"
        then
            echo "test succeeded"
            lasttest=success
            doubtful="$tested"
        else
            echo "test failed"
            lasttest=failure
            set +x
            newdoubtful=""
            for module in $doubtful
            do
                if not appears $module $tested
                then
                    newdoubtful="$newdoubtful $module"
                fi
            done
            set -x
            doubtful="$newdoubtful"
        fi
    else
        if binary_step $bootcheck $compile_only $compare_to_bad \
            $dependency_only $library_only $jfactor $grade_opt \
            -m "$mmake_opts" $outfile $testdirs -s "$single_command"
        then
            echo "test succeeded"
            lasttest=success
            knowngood="$knowngood $tested"
            set +x
            newdoubtful=""
            for module in $doubtful
            do
                if not appears $module $tested
                then
                    newdoubtful="$newdoubtful $module"
                fi
            done
            set -x
            doubtful="$newdoubtful"
        else
            echo "test failed"
            lasttest=failure
            doubtful="$tested"
        fi
    fi

    for module in $tested
    do
        cp stage2.$base/$testeddir/$module.[co] stage2/$testeddir
        case "${testeddir}" in
            library|mdbcomp|browser)
                cp stage2.$base/${testeddir}/$module.pic_o stage2/${testeddir}
                ;;
        esac
    done

    tested=`half $doubtful`
    if test "$tested" = "" -a "$lasttest" = "$expected"
    then
        tested="$doubtful"
    fi
done

if test "$doubtful" = ""
then
    echo "cannot find the problem; all modules behave as expected"
    exit 1
fi

module=`echo $doubtful | tr -d ' '`

if "$negative"
then
    true
else
    echo "the modules known to be ok are: $knowngood"
fi
echo "there is a problem in $testeddir/$module"
echo

basecnt=`egrep '^MR_END_MODULE' stage2.$base/$testeddir/$module.c | wc -l`
trialcnt=`egrep '^MR_END_MODULE' stage2.$trial/$testeddir/$module.c | wc -l`

if test $basecnt -ne $trialcnt
then
    basecnt=`echo $basecnt | tr -d ' '`
    trialcnt=`echo $trialcnt | tr -d ' '`

    echo "the two versions of the problem module"
    echo "differ in the number of C modules they have"
    echo "$base version: $basecnt vs $trial version: $trialcnt"
    exit 1
fi

for dir in $base $trial
do
    cd stage2.$dir/$testeddir
    divide $module.c $basecnt
    cd $root
done

set +x
doubtful=
knowngood=
i=0
while test $i -le $basecnt
do
    # If two corresponding parts from stage2.ok and stage.bad are the same,
    # then the bug cannot be in that part.
    if cmp -s \
        stage2.$base/$testeddir/$module.c.part.$i \
        stage2.$trial/$testeddir/$module.c.part.$i
    then
        knowngood="$knowngood $i"
    else
        doubtful="$doubtful $i"
    fi
    i=`expr $i + 1`
done
set -x

tested=`half $doubtful`

/bin/rm -fr .stage2_problem > /dev/null 2>&1

while test "$tested" != ""
do
    echo "knowngood: $knowngood"
    echo "doubtful:  $doubtful"
    echo "testing:   $tested"

    assemble $base $trial $testeddir $module $basecnt $tested
    cd stage2/$testeddir
    /bin/rm $module.o
    mmake ${mmake_grade_opt} $module.o
    cd $root

    if "$negative"
    then
        if binary_step $bootcheck $compile_only $compare_to_bad \
            $dependency_only $library_only $jfactor $grade_opt \
            -m "$mmake_opts" $outfile $testdirs -s "$single_command"
        then
            echo "test succeeded"
            lasttest=success
            doubtful="$tested"
        else
            echo "test failed"

            if test -f .stage2_problem
            then
                /bin/rm .stage2_problem > /dev/null 2>&1
                echo "problem with the creation of stage 2:"
                echo "search of $testeddir/$module abandoned"
                exit 1
            fi

            lasttest=failure
            set +x
            newdoubtful=""
            for part in $doubtful
            do
                if not appears $part $tested
                then
                    newdoubtful="$newdoubtful $part"
                fi
            done
            set -x
            doubtful="$newdoubtful"
        fi
    else
        if binary_step $bootcheck $compile_only $compare_to_bad \
            $dependency_only $library_only $jfactor $grade_opt \
            -m "$mmake_opts" $outfile $testdirs -s "$single_command"
        then
            echo "test succeeded"
            lasttest=success
            knowngood="$knowngood $tested"
            set +x
            newdoubtful=""
            for part in $doubtful
            do
                if not appears $part $tested
                then
                    newdoubtful="$newdoubtful $part"
                fi
            done
            set -x
            doubtful="$newdoubtful"
        else
            echo "test failed"

            if test -f .stage2_problem
            then
                /bin/rm .stage2_problem > /dev/null 2>&1
                echo "problem with the creation of stage 2:"
                echo "search of $testeddir/$module abandoned"
                exit 1
            fi

            lasttest=failure
            doubtful="$tested"
        fi
    fi

    tested=`half $doubtful`
    if test "$tested" = "" -a "$lasttest" = "$expected"
    then
        tested="$doubtful"
    fi
done

if test "$doubtful" = ""
then
    echo "cannot find the problem; all parts behave as expected"
    exit 1
fi

doubtful=`echo $doubtful | tr -d ' '`

if "$negative"
then
    true
else
    echo "the parts known to be ok are: $knowngood"
fi
echo "there is a problem in $testeddir/$module.c.part.$doubtful"
echo "the difference is:"
echo

diff -u stage2.$base/$testeddir/$module.c.part.$doubtful stage2.$trial/$testeddir/$module.c.part.$doubtful

echo
echo "finishing at `date`"
exit 0