Reduce the install size of clang, llvm, lld and gcc on MSYS2

ln-mingw.sh

#!/bin/sh

# Convert the same files into hard links to reduce the install size of
# clang, llvm, lld and gcc on MSYS2.

ESC=$'\33'
GREEN="$ESC[32m"
YELLOW="$ESC[33m"
CYAN="$ESC[36m"
RESET="$ESC[m"

do_link()
{
	TARGET=$1
	LINK=$2

	if [ -h $TARGET ] || [ -h $LINK ] || [ ! -f $TARGET ] || [ ! -f $LINK ]; then
		# Skip symlinks and non-normal files.
		return
	fi
	# Check i-node number
	if gawk -v t=$TARGET -v l=$LINK '@load "filefuncs";
			BEGIN{stat(t, f1); stat(l, f2);
			exit f1["ino"] != f2["ino"]}'; then
		echo "${CYAN}Already hard-linked:${RESET} $LINK - $TARGET"
		return
	fi
	# Check if the content of files are exactly the same.
	if diff $TARGET $LINK > /dev/null; then
		# Convert to a hard link.
		echo "${YELLOW}Linking:${RESET} $LINK - $TARGET"
		ln -f $TARGET $LINK
	fi
}

link_files()
{
	if [ $# -lt 2 ]; then
		return
	fi

	# 1. Check if all the i-node numbers are the same if the file sizes are the same.
	# 2. Check the MD5 if the i-node numbers are different.
	# 3. Link if the MD5 are the same.
	stat -c '%s %i %n' "$@" | \
		gawk '
{
	name[$1][$3]
	inode[$1][$2]
}
END {
	for (i in inode) {
		if (length(inode[i]) > 1) {
			asorti(name[i], n)
			for (j in n) {
				print n[j]
			}
		}
	}
}' | \
		xargs md5sum 2> /dev/null | \
		awk -F ' [* ]' '{if ($1 in a) {print a[$1], $2} else {a[$1]=$2}}' | \
		while read LINE; do
			eval do_link $LINE
		done
}

do_gcc_bin()
{
	GCC_BINDIR=$1

	pushd $GCC_BINDIR > /dev/null

	echo "${GREEN}Directory:${RESET} $GCC_BINDIR"
	files=''
	for i in *.exe; do
		files="$files \"$i\" \"../../bin/$i\""
	done
	eval link_files $files

	popd > /dev/null
}

do_top()
{
	TOP=$1
	TRIPLET=$2

	if [ -d $TOP/$TRIPLET/bin ]; then
		do_gcc_bin $TOP/$TRIPLET/bin
	fi

	BINDIR=$TOP/bin
	if ! [ -d $BINDIR ]; then
		return
	fi

	pushd $BINDIR > /dev/null

	echo "${GREEN}Directory:${RESET} $BINDIR"
	link_files *

	popd > /dev/null
}

do_top /mingw32 i686-w64-mingw32
do_top /mingw64 x86_64-w64-mingw32
do_top /ucrt64 x86_64-w64-mingw32
do_top /clang32 NONE
do_top /clang64 NONE
do_top /usr x86_64-pc-msys

See MSYS2上のclang, llvm, lld, gccのインストールサイズを減らす for detail.