#!/bin/sh -e
#
# The script allows to override 'CC', 'CFLAGS' and 'flavour' at command
# line, as well as specify additional compiler flags. For example to
# compile for x32:
#
#	/some/where/build.sh flavour=elf32 -mx32
#
# To cross-compile for mingw/Windows:
#
#	/some/where/build.sh flavour=mingw64 CC=x86_64-w64-mingw32-gcc
#
# In addition script recognizes -shared flag and creates shared library
# alongside libblst.a.
#
# To cross-compile for WebAssembly with Emscripten SDK:
#
#	/some/where/build.sh CROSS_COMPILE=em

[ -d /usr/xpg4/bin ] && PATH=/usr/xpg4/bin:$PATH # Solaris

TOP=`dirname $0`

# if -Werror stands in the way, bypass with -Wno-error on command line,
# or suppress specific one with -Wno-<problematic-warning>
CFLAGS=${CFLAGS:--O2 -fno-builtin -fPIC -Wall -Wextra -Werror}
PERL=${PERL:-perl}
unset cflags shared dll

case `uname -s` in
    Darwin)	flavour=macosx
                if [ "`sysctl -n hw.optional.adx 2>/dev/null`" = "1" ]; then
                    cflags="-D__ADX__"
                fi
                ;;
    CYGWIN*)	flavour=mingw64;;
    MINGW*)	flavour=mingw64;;
    *)		flavour=elf;;
esac

while [ "x$1" != "x" ]; do
    case $1 in
        -shared)    shared=1;;
        -dll)       shared=1; dll=".dll";;
        -m*)        CFLAGS="$CFLAGS $1";;
        -*target*)  CFLAGS="$CFLAGS $1";;
        -*)         cflags="$cflags $1";;
        *=*)        eval "$1";;
    esac
    shift
done

if [ "x$CC" = "x" ]; then
    CC=gcc
    which ${CROSS_COMPILE}cc >/dev/null 2>&1 && CC=cc
fi
if which ${CROSS_COMPILE}${CC} >/dev/null 2>&1; then
    CC=${CROSS_COMPILE}${CC}
fi
if [ "x$CROSS_COMPILE" = "x" ]; then
    CROSS_COMPILE=`echo $CC |
                   awk '{ print substr($1,0,match($1,"-(g?cc|clang)$")) }' 2>/dev/null`
    # fix up android prefix...
    CROSS_COMPILE=`echo $CROSS_COMPILE |
                   awk '{ off=match($1,"-android[0-9]+-");
                          if (off) { printf "%sandroid-\n",substr($1,0,off) }
                          else     { print $1 } }'`
fi

predefs=`(${CC} ${CFLAGS} -dM -E -x c /dev/null || true) 2>/dev/null`

if [ -z "${CROSS_COMPILE}${AR}" ] && echo ${predefs} | grep -q clang; then
    search_dirs=`${CC} -print-search-dirs  | awk -F= '/^programs:/{print$2}' | \
                 (sed -E -e 's/([a-z]):\\\/\/\1\//gi' -e 'y/\\\;/\/:/' 2>/dev/null || true)`
    if [ -n "$search_dirs" ] && \
       env PATH="$search_dirs:$PATH" which llvm-ar > /dev/null 2>&1; then
        PATH="$search_dirs:$PATH"
        AR=llvm-ar
    fi
fi
AR=${AR:-${CROSS_COMPILE}ar}

if echo ${predefs} | grep -q x86_64; then
    if (grep -q -e '^flags.*\badx\b' /proc/cpuinfo) 2>/dev/null; then
        cflags="-D__ADX__ $cflags"
    fi
fi
if echo ${predefs} | grep -q __AVX__; then
    cflags="$cflags -mno-avx" # avoid costly transitions
fi
if echo ${predefs} | grep -q 'x86_64\|aarch64'; then :; else
    cflags="$cflags -D__BLST_NO_ASM__"
fi

CFLAGS="$CFLAGS $cflags"
TMPDIR=${TMPDIR:-/tmp}

rm -f libblst.a
trap '[ $? -ne 0 ] && rm -f libblst.a; rm -f *.o ${TMPDIR}/*.blst.$$' 0

(set -x; ${CC} ${CFLAGS} -c ${TOP}/src/server.c)
(set -x; ${CC} ${CFLAGS} -c ${TOP}/build/assembly.S)
(set -x; ${AR} rc libblst.a *.o)

if [ $shared ]; then
    case $flavour in
        macosx) (set -x; ${CC} -dynamiclib -o libblst$dll.dylib \
                               -all_load libblst.a ${CFLAGS}); exit 0;;
        mingw*) sharedlib="blst.dll ${TOP}/build/win64/blst.def"
                CFLAGS="${CFLAGS} --entry=DllMain ${TOP}/build/win64/dll.c"
                CFLAGS="${CFLAGS} -nostdlib -lgcc";;
        *)      sharedlib=libblst$dll.so;;
    esac
    (set -x; ${CC} -shared -o $sharedlib \
                   -Wl,--whole-archive,libblst.a,--no-whole-archive ${CFLAGS} \
                   -Wl,-Bsymbolic)
fi