configure

#!/bin/sh

fail() {
	echo "$0: $*" >&2
	exit 1
}

prefix=/usr/local
bindir='$(PREFIX)/bin'
host=
target=
gcclibdir=

for arg ; do
	case "$arg" in
	--prefix=*) prefix=${arg#*=} ;;
	--bindir=*) bindir=${arg#*=} ;;
	--host=*) host=${arg#*=} ;;
	--target=*) target=${arg#*=} ;;
	--with-cpp=*) DEFAULT_CPP=${arg#*=} ;;
	--with-qbe=*) DEFAULT_QBE=${arg#*=} ;;
	--with-as=*) DEFAULT_AS=${arg#*=} ;;
	--with-ld=*) DEFAULT_LD=${arg#*=} ;;
	--with-ldso=*) DEFAULT_LDSO=${arg#*=} ;;
	--with-gcc-libdir=*) gcclibdir=${arg#*=} ;;
	--with-macos-sdk=*) macossdk=${arg#*=} ;;
	CC=*) CC=${arg#*=} ;;
	CFLAGS=*) CFLAGS=${arg#*=} ;;
	LDFLAGS=*) LDFLAGS=${arg#*=} ;;
	*) fail "unknown option '$arg'"
	esac
done

: ${CC:=cc}

printf 'checking host system type... '
test -n "$host" || host=$($CC -dumpmachine 2>/dev/null) || fail "could not determine host"
printf '%s\n' "$host"

printf 'checking target system type... '
test -n "$target" || target=$host
printf '%s\n' "$target"

toolprefix=
if [ "$host" != "$target" ] ; then
	toolprefix=$target-
fi

startfiles=0
endfiles=0
linkflags=
defines='
	"-D", "__STDC_ENDIAN_LITTLE__=1234",
	"-D", "__STDC_ENDIAN_BIG__=4321",
	"-D", "__STDC_ENDIAN_NATIVE__=__STDC_ENDIAN_LITTLE__",
	"-D", "__ORDER_LITTLE_ENDIAN__=__STDC_ENDIAN_LITTLE__",
	"-D", "__ORDER_BIG_ENDIAN__=__STDC_ENDIAN_BIG__",
	"-D", "__BYTE_ORDER__=__STDC_ENDIAN_NATIVE__",
	"-D", "__FLT_EVAL_METHOD__=1",
	"-D", "__BITINT_MAXWIDTH__=64",
'

model=
case "$target" in
x86_64-*x32)
	fail "unsupported target '$target'";;
x86_64-*|amd64-*)
	model=lp64
	# __amd64__ is used by at least freebsd
	defines=$defines'
	"-D", "__x86_64__",
	"-D", "__amd64__",
'
	;;
aarch64-*)
	model=lp64
	defines=$defines'
	"-D", "__aarch64__",
'
	;;
riscv64-*)
	model=lp64
	defines=$defines'
	"-D", "__riscv",
	"-D", "__riscv_i=2001000",
	"-D", "__riscv_m=2000000",
	"-D", "__riscv_a=2001000",
	"-D", "__riscv_f=2002000",
	"-D", "__riscv_d=2002000",
	"-D", "__riscv_c=2000000",
	"-D", "__riscv_xlen=64",
	"-D", "__riscv_flen=64",
'
	;;
*)
	fail "unsupported target '$target'";;
esac

case "$model" in
lp64)
	# __SIZEOF_LONG__ is used by freebsd
	defines=$defines'
	"-D", "__LP64__",
	"-D", "__SIZEOF_LONG__=8",
	"-D", "__SIZEOF_POINTER__=8",
	"-D", "__SIZEOF_SIZE_T__=8",
	"-D", "__SIZEOF_PTRDIFF_T__=8",
'
	;;
*)
	fail "unsupported model '$target'";;
esac

case "$target" in
*-linux-*musl*)
	test "${DEFAULT_LDSO+set}" || case "$target" in
	x86_64*)  DEFAULT_LDSO=/lib/ld-musl-x86_64.so.1  ;;
	aarch64*) DEFAULT_LDSO=/lib/ld-musl-aarch64.so.1 ;;
	riscv64*) DEFAULT_LDSO=/lib/ld-musl-riscv64.so.1 ;;
	*) fail "unsuported target '$target'"
	esac
	startfiles='"-l", ":crt1.o", "-l", ":crti.o"'
	endfiles='"-l", "c", "-l", ":crtn.o"'
	defines=$defines'
	"-D", "__linux__",
	"-D", "__unix__",
'
	;;
*-linux-*gnu*)
	test "${DEFAULT_LDSO+set}" || case "$target" in
	x86_64*)  DEFAULT_LDSO=/lib64/ld-linux-x86-64.so.2 ;;
	aarch64*) DEFAULT_LDSO=/lib/ld-linux-aarch64.so.1  ;;
	riscv64*) DEFAULT_LDSO=/lib/ld-linux-riscv64-lp64d.so.1 ;;
	*) fail "unsuported target '$target'"
	esac
	startfiles='"-l", ":crt1.o", "-l", ":crti.o", "-l", ":crtbegin.o"'
	endfiles='"-l", "c", "-l", ":crtend.o", "-l", ":crtn.o"'
	if [ -z "$gcclibdir" ] ; then
		test "$host" = "$target" || fail "gcc libdir must be specified when building a cross-compiler"
		crtbegin=$($CC -print-file-name=crtbegin.o 2>/dev/null)
		gcclibdir=${crtbegin%/*}
	fi
	linkflags='"-L", "'$gcclibdir'",'
	# __INT_MAX__ and __LONG_LONG_MAX__ are used by gcc's limits.h
	defines=$defines'
	"-D", "__linux__",
	"-D", "__unix__",
	"-D", "__INT_MAX__=0x7fffffff",
	"-D", "__LONG_LONG_MAX__=0x7fffffffffffffffL",
'
	;;
*-*freebsd*)
	: ${DEFAULT_LDSO:=/libexec/ld-elf.so.1}
	startfiles='"-l", ":crt1.o", "-l", ":crti.o"'
	endfiles='"-l", "c", "-l", ":crtn.o"'
	linkflags='"-L", "/usr/lib",'
	defines=$defines'
	"-D", "__FreeBSD__",
	"-D", "__unix__",

	"-D", "_Pragma(x)=",
	"-D", "_Nullable=",
	"-D", "_Nonnull=",

	"-D", "__GNUCLIKE_BUILTIN_STDARG",
	"-D", "__GNUCLIKE_BUILTIN_VARARGS",

	/* disable TLS for rune locale (needs initial-exec TLS, #103 */
	"-D", "__RUNETYPE_INTERNAL",

	/* required to define _RuneLocale, needed by xlocale/_ctype.h */
	"-D", "_USE_CTYPE_INLINE_",
	/* workaround for #42 */
	"-D", "_XLOCALE_INLINE=static inline",

	/* disable warnings for redefining _Pragma */
	"-Wno-builtin-macro-redefined",
'
	;;
*-*dragonflybsd*)
	: ${DEFAULT_LDSO:=/libexec/ld-elf.so.2}
	startfiles='"-l", ":crt1.o", "-l", ":crti.o"'
	endfiles='"-l", "c", "-l", ":crtn.o"'
	linkflags='"-L", "/usr/lib",'
	defines=$defines'
	"-D", "__DragonFly__",
	"-D", "__unix__",

	"-D", "_Pragma(x)=",
	"-D", "_Nullable=",
	"-D", "_Nonnull=",

	"-D", "__GNUCLIKE_BUILTIN_STDARG",
	"-D", "__GNUCLIKE_BUILTIN_VARARGS",

	/* disable TLS for errno and rune locale (needs initial-exec TLS, #103) */
	"-D", "__WANT_NO_INLINED___ERROR",
	"-D", "__RUNETYPE_INTERNAL",

	/* required to define _RuneLocale, needed by xlocale/_ctype.h */
	"-D", "_USE_CTYPE_INLINE_",
	/* workaround for #42 */
	"-D", "_XLOCALE_INLINE=static inline",

	/* disable warnings for redefining _Pragma */
	"-Wno-builtin-macro-redefined",
'
	;;
*-*openbsd*)
	: ${DEFAULT_LDSO:=/usr/libexec/ld.so}
	test "$host" = "$target" && : ${DEFAULT_CPP:=/usr/libexec/cpp} ${DEFAULT_AS:=gas}
	startfiles='"-l", ":crt0.o", "-l", ":crtbegin.o"'
	endfiles='"-l", "c", "-l", ":crtend.o"'
	linkflags='"-L", "/usr/lib", "-nopie",'
	defines=$defines'
	"-D", "__OpenBSD__",
	"-D", "__unix__",

	/* required to prevent libc headers from declaring functions with conflicting linkage */
	"-D", "_ANSI_LIBRARY",

	/* these are used unconditionally, but only defined with __GNUC__ or __PCC__ */
	"-D", "__aligned(a)=[[__gnu__::__aligned__(a)]]",
	"-D", "__packed=[[__gnu__::__packed__]]",

	/* disable warnings for redefining __FLT_EVAL_METHOD__ */
	"-Wno-builtin-macro-redefined",
'
	;;
*-*netbsd*)
	: ${DEFAULT_LDSO:=/usr/libexec/ld.elf_so}
	startfiles='"-l", ":crt0.o", "-l", ":crti.o"'
	endfiles='"-l", "c", "-l", ":crtn.o"'
	defines=$defines'
	"-D", "__NetBSD__",
	"-D", "__unix__",

	"-D", "__builtin_stdarg_start(ap, last)=__builtin_va_start(ap, last)",

	"-D", "__CHAR_BIT__=8",
	"-D", "__SCHAR_MAX__=0x7f",
	"-D", "__SHRT_MAX__=0x7fff",
	"-D", "__INT_MAX__=0x7fffffff",
	"-D", "__LONG_MAX__=__LONG_LONG_MAX__",
	"-D", "__LONG_LONG_MAX__=0x7fffffffffffffffL",
	"-D", "__WINT_TYPE__=int",
	"-D", "__WCHAR_TYPE__=int",
	"-D", "__SIZE_TYPE__=unsigned long",
	"-D", "__PTRDIFF_TYPE__=long",
'
	;;
*-apple-darwin*)
	: ${DEFAULT_CPP:=clang -E}
	startfiles='0'
	endfiles='"-l", "System"'
	defines=$defines'
	"-D", "__APPLE__",
	"-D", "__unix__",

	"-D", "_Nullable=",
	"-D", "__compar=",
	"-U", "__BLOCKS__",
'
	if [ -z "$macossdk" ] ; then
		test "$host" = "$target" || fail "macos sdk must be specified when building a cross-compiler"
		macossdk=$(xcrun --show-sdk-path)
	fi
	linkflags='"-syslibroot", "'$macossdk'"'
	;;
*)
	fail "unknown target '$target', please create config.h manually"
esac

DEFAULT_CPP=$(printf '"%s", ' ${DEFAULT_CPP:-${toolprefix}cpp})
DEFAULT_QBE=$(printf '"%s", ' ${DEFAULT_QBE:-qbe})
DEFAULT_AS=$(printf '"%s", ' ${DEFAULT_AS:-${toolprefix}as})
DEFAULT_LD=$(printf '"%s", ' ${DEFAULT_LD:-${toolprefix}ld})

test -n "$DEFAULT_LDSO" && linkflags=$linkflags' "--dynamic-linker", "'$DEFAULT_LDSO'"'

printf "creating config.h... "
cat >config.h <<EOF
static const char target[]               = "$target";
static const char *const startfiles[]    = {$startfiles};
static const char *const endfiles[]      = {$endfiles};
static const char *const preprocesscmd[] = {
	$DEFAULT_CPP"-undef",

	/* we don't yet support these optional features */
	"-D", "__STDC_NO_ATOMICS__",
	"-D", "__STDC_NO_COMPLEX__",

	/* ignore extension markers */
	"-D", "__extension__=",
$defines};
static const char *const codegencmd[]    = {$DEFAULT_QBE};
static const char *const assemblecmd[]   = {$DEFAULT_AS};
static const char *const linkcmd[]       = {$DEFAULT_LD$linkflags};
EOF
echo done

printf "creating config.mk... "
cat >config.mk <<EOF
PREFIX=$prefix
BINDIR=$bindir
CC=${CC:-cc}
CFLAGS=${CFLAGS:--Wall -Wpedantic -Wno-parentheses -Wno-switch -g -pipe}
LDFLAGS=$LDFLAGS
EOF
echo done