configure

#!/bin/sh

# hlibc configure script


print() {
	printf -- "%s\n" "$*"
}

menu()
{
	print "hlibc 2016-2018, CM Graff et al.

	Usage:

	--prefix=PREFIX	 main installation prefix [/usr/local/hlibc]

	Command line variables are added last to the config.mak and passed
	to the makefile. For instance:

	./configure AS='cc -x assembler'


	"
	exit 0
}

fatal()
{
	(>&2 print "fatal" "$*")
	exit 1
}

detectcommand()
{
	printf "trying $i .. "
	if command -v "$1" >/dev/null 2>&1
	then	print "yes"
		return 0
	else	print "no"
		return 1
	fi
}

inspect_compiler()
{
	printf "trying %s .. " "$2"
	print "long y = 1;" > "$temporary_file"
	print "double z = 0;" >> "$temporary_file"
	if "$CC" "$2" -c -o .temporary "$temporary_file" 2> .temporary
	then	print "yes"
		eval "$1=\"\${$1} \$2\""
		eval "$1=\${$1# }"
		return 0
	else	print "no"
		return 1
	fi
}


OPERATING_SYSTEM="linux"
FREESTANDING=
CFLAGS_SUPPLEMENT=
prefix="/usr/local/hlibc"
architecture=

print "# Automatically generated" > config.mak

for i in "$@"
do	case "$i" in
		-h|--help)
			menu
			;;
		--prefix=*)
			prefix=${i#*=}
			;;
		*=*)
			# Let these be added at the end
			;;
		*)
			fatal "$i is not a valid option !!"
			;;
	esac
done

# Detect the operating system
OS_DIRTY_STR=$(uname -a)

case $OS_DIRTY_STR in
	*linux*|*Linux*)
		OPERATING_SYSTEM="linux"
			;;
	*aix*)
		OPERATING_SYSTEM="aix"
			;;
	*FreeBSD*|*freebsd*|*Freebsd*)
		print "Note that the FreeBSD 'c99' command has a bug and won't accept '-dumpmachine'"
		OPERATING_SYSTEM="freebsd"
			;;
	*NetBSD*|*netbsd*|*Netbsd*)
		print "NetBSD is not fully supported."
		print "It will build, and likely works, however NetBSD needs a note in the ELF headers"
		print "which hlibc has no functionality to provide at this time."
		OPERATING_SYSTEM="netbsd"
			;;
	*Darwin*|*darwin*)
		OPERATING_SYSTEM="macos"
			;;
	*OpenBSD*|*openbsd*|*Openbsd*)
		OPERATING_SYSTEM="openbsd"
			;;
esac

# Obtain a temporary file
temporary_file="./temporary_work_file"
[ -f "${temporary_file}" ] && rm "$temporary_file"

print "Attempting to detect a C compiler ..."
if [ -z "${CC}" ]
then	for i in unlikely-cc gcc cc clang c99 pcc tcc
	do	if detectcommand "$i"
		then	CC="$i"
			break
		fi
	done
	if [ -z "${CC}" ]
	then	fatal "No compiler was able to be found. Giving up."
	fi
else	detectcommand "${CC}"
fi

# Find target architecture
printf "Automatically detecting the computer architecture: "
architecture=$("$CC" -dumpmachine 2>/dev/null)

if [ -z "$architecture" ]
then	print
	print "Warning: $CC does not appear to support -dumpmachine"
	print "Falling back to uname -m which is not compiler specific"
	print "This will mess up cross compiling unless your host and target are the same"
	architecture=$(uname -m 2>/dev/null)
fi

print "$architecture"

case "$architecture" in
	*i*86*)
		ARCH="i386"
		;;
	*arm64*|*aarch64*)
		ARCH="aarch64"
		;;
	*amd64*|x86_64*)
		ARCH="x86_64"
		;;
	*)
		fatal "Unknown architecture !!"
		;;
esac


# one offs
AS="as"
if [ $OPERATING_SYSTEM = "openbsd" -a $ARCH = "aarch64" ]
then export AS="$CC -x assembler"
fi

# Obtain a freestanding C99 env
inspect_compiler FREESTANDING -ffreestanding
inspect_compiler FREESTANDING -std=c99
inspect_compiler FREESTANDING -nostdinc
inspect_compiler CFLAGS_SUPPLEMENT -pipe
inspect_compiler CFLAGS_SUPPLEMENT -Os

# Correct broken compiler installations
inspect_compiler CFLAGS_SUPPLEMENT -fno-stack-protector
inspect_compiler DISABLE_PIE -fno-pie
inspect_compiler DISABLE_PIE -no-pie

# Create the config.mak
print "Generating a config.mak for the main Makefile"

print "

ARCH = $ARCH
prefix = $prefix
CC = $CC
CFLAGS += $CFLAGS_SUPPLEMENT $CFLAGS
FREESTANDING += $FREESTANDING
DISABLE_PIE += $DISABLE_PIE
OPERATING_SYSTEM += $OPERATING_SYSTEM
AS = $AS
" > config.mak

# Adjust the compiler wrapper if clang is being used
case "$CC" in
	*clang*)
		print "CC_IS_CLANG = yes" >> config.mak
		print "" >> config.mak
		;;
esac

for i in "$@"
do	case "$i" in
		*=*)	print "${i%=*} = ${i#*=}" >> config.mak ;;
	esac
done

# Clean up and report
rm "$temporary_file" .temporary

print "done"