Proof of concept:Combine _info symbols split by ghc back into larger object files.

combine.sh

#!/bin/bash

# Find which object split includes a given definition
findobj () {
    for a in ${1}_p_o_split.new/*.p_o; do
        if nm $a | grep --color=auto -q " T $2"; then
            echo $a;
            break;
        fi;
    done
}

# Given an "...X_info" symbol, list the other
# ...X1_info
# ...X2_info etc symbols
otherobjs () {
    nm $1.p_o | grep " T ${2%_info}[0-9]\+_info" | cut -d' ' -f3
}

combine () {
    # echo "# Looking at $2"
    OTHER=$(otherobjs $1 $2)
    if [ -z "$OTHER" ]; then
        # echo "# Nah, didn't find anything"
        return
    fi
    F=""
    for a in $OTHER; do
        F="$F `findobj $1 $a`";
    done
    MAIN=$(findobj $1 $2)
    echo ld -r $F $MAIN -o $MAIN.new.o
    ld -r $F $MAIN -o $MAIN.new.o
    echo rm $F $MAIN
    rm $F $MAIN
    echo mv $MAIN.new.o $MAIN
    mv $MAIN.new.o $MAIN
}


if [ ! -f $UNSPLIT ]; then
    echo "First argument should be the module name.  Can't find $UNSPLIT"
fi

if [ ! -d $SPLITDIR ]; then
    echo "Can't find $SPLITDIR.  You must run ghc with --split-dirs"
fi

UNSPLIT=${1}.p_o
SPLITDIR=${1}_p_o_split
NEWSPLITDIR=${1}_p_o_split.new

echo "# Removing $NEWSPLITDIR"
rm -rf $NEWSPLITDIR
mkdir -p $NEWSPLITDIR
cp $SPLITDIR/* $NEWSPLITDIR/

# List the main symbols ending in _info
infos () {
    nm $1.p_o | grep ' T .*[^0-9]_info'
}


infos $1 | while read a b c; do
    combine $1 $c
done