build_detect_platform

#!/bin/sh
#
# Detects OS we're compiling on and outputs a file specified by the first
# argument, which in turn gets read while processing Makefile.
#
# The output will set the following variables:
#   CC                          C Compiler path
#   CXX                         C++ Compiler path
#   PLATFORM_LDFLAGS            Linker flags
#   PLATFORM_SHARED_EXT         Extension for shared libraries
#   PLATFORM_SHARED_LDFLAGS     Flags for building shared library
#   PLATFORM_SHARED_CFLAGS      Flags for compiling objects for shared library
#   PLATFORM_CCFLAGS            C compiler flags
#   PLATFORM_CXXFLAGS           C++ compiler flags.  Will contain:
#   PLATFORM_SHARED_VERSIONED   Set to 'true' if platform supports versioned
#                               shared libraries, empty otherwise.

OUTPUT=$1
if test -z "$OUTPUT"; then
  echo "usage: $0 <output-filename>" >&2
  exit 1
fi

# we depend on C++11
PLATFORM_CXXFLAGS="-std=c++11"
# we currently depend on POSIX platform
COMMON_FLAGS=

# Delete existing output, if it exists
rm -f "$OUTPUT"
touch "$OUTPUT"

if test -z "$CC"; then
   CC=cc
fi

if test -z "$CXX"; then
    CXX=g++
fi

# Detect OS
if test -z "$TARGET_OS"; then
    TARGET_OS=`uname -s`
fi

if test -z "$TARGET_ARCHITECTURE"; then
    TARGET_ARCHITECTURE=`uname -m`
fi

COMMON_FLAGS="$COMMON_FLAGS ${CFLAGS}"
CROSS_COMPILE=
PLATFORM_CCFLAGS=
PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS"
PLATFORM_SHARED_EXT="so"
PLATFORM_SHARED_LDFLAGS="-Wl,--no-as-needed -shared -Wl,-soname -Wl,"
PLATFORM_SHARED_CFLAGS="-fPIC"
PLATFORM_SHARED_VERSIONED=true

# On GCC, we pick libc's memcmp over GCC's memcmp via -fno-builtin-memcmp
case "$TARGET_OS" in
    Darwin)
        PLATFORM=OS_MACOSX
        COMMON_FLAGS="$COMMON_FLAGS -DOS_MACOSX"
        PLATFORM_SHARED_EXT=dylib
        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name "
        # PORT_FILES=port/darwin/darwin_specific.cc
        ;;
    IOS)
        PLATFORM=IOS
        COMMON_FLAGS="$COMMON_FLAGS -DOS_MACOSX -DIOS_CROSS_COMPILE "
        PLATFORM_SHARED_EXT=dylib
        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name "
        CROSS_COMPILE=true
        PLATFORM_SHARED_VERSIONED=
        ;;
    Linux)
        PLATFORM=OS_LINUX
        COMMON_FLAGS="$COMMON_FLAGS -DOS_LINUX"
        if [ -z "$USE_CLANG" ]; then
            COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp"
        fi
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lpthread -lrt"
        # PORT_FILES=port/linux/linux_specific.cc
        ;;
    SunOS)
        PLATFORM=OS_SOLARIS
        COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp -D_REENTRANT -DOS_SOLARIS"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lpthread -lrt"
        # PORT_FILES=port/sunos/sunos_specific.cc
        ;;
    FreeBSD)
        PLATFORM=OS_FREEBSD
        COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp -D_REENTRANT -DOS_FREEBSD"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lpthread"
        # PORT_FILES=port/freebsd/freebsd_specific.cc
        ;;
    NetBSD)
        PLATFORM=OS_NETBSD
        COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp -D_REENTRANT -DOS_NETBSD"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lpthread -lgcc_s"
        # PORT_FILES=port/netbsd/netbsd_specific.cc
        ;;
    OpenBSD)
        PLATFORM=OS_OPENBSD
        COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp -D_REENTRANT -DOS_OPENBSD"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -pthread"
        # PORT_FILES=port/openbsd/openbsd_specific.cc
        ;;
    DragonFly)
        PLATFORM=OS_DRAGONFLYBSD
        COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp -D_REENTRANT -DOS_DRAGONFLYBSD"
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lpthread"
        # PORT_FILES=port/dragonfly/dragonfly_specific.cc
        ;;
    Cygwin)
        PLATFORM=CYGWIN
        PLATFORM_SHARED_CFLAGS=""
        PLATFORM_CXXFLAGS="-std=gnu++11"
        COMMON_FLAGS="$COMMON_FLAGS -DCYGWIN"
        if [ -z "$USE_CLANG" ]; then
            COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp"
        fi
        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lpthread -lrt"
        # PORT_FILES=port/linux/linux_specific.cc
        ;;
    OS_ANDROID_CROSSCOMPILE)
        PLATFORM=OS_ANDROID
	COMMON_FLAGS="$COMMON_FLAGS -fno-builtin-memcmp -D_REENTRANT -DOS_ANDROID "
	PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS "  # All pthread features are in the Android C library
        # PORT_FILES=port/android/android.cc
        CROSS_COMPILE=true
        ;;
    *)
        echo "Unknown platform!" >&2
        exit 1
esac

PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS ${CXXFLAGS}"

if [ "$CROSS_COMPILE" = "true" ]; then
    # Cross-compiling; do not try any compilation tests.
    # Also don't need any compilation tests if compiling on fbcode
    true
else
    if ! test $ROCKSUTIL_DISABLE_FALLOCATE; then
        # Test whether fallocate is available
        $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
          #include <fcntl.h>
          #include <linux/falloc.h>
          int main() {
      int fd = open("/dev/null", 0);
      fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, 1024);
          }
EOF
        if [ "$?" = 0 ]; then
            COMMON_FLAGS="$COMMON_FLAGS -DROCKSUTIL_FALLOCATE_PRESENT"
        fi
    fi

    # Test whether PTHREAD_MUTEX_ADAPTIVE_NP mutex type is available
    $CXX $CFLAGS -x c++ - -o /dev/null 2>/dev/null  <<EOF
      #include <pthread.h>
      int main() {
        int x = PTHREAD_MUTEX_ADAPTIVE_NP;
        return 0;
      }
EOF
    if [ "$?" = 0 ]; then
        COMMON_FLAGS="$COMMON_FLAGS -DROCKSUTIL_PTHREAD_ADAPTIVE_MUTEX"
    fi

    # Test if -pg is supported
    $CXX $CFLAGS -pg -x c++ - -o /dev/null 2>/dev/null  <<EOF
      int main() {
        return 0;
      }
EOF
    if [ "$?" = 0 ]; then
        PROFILING_FLAGS=-pg
    fi
fi

# TODO(tec): Fix -Wshorten-64-to-32 errors on FreeBSD and enable the warning.
# -Wshorten-64-to-32 breaks compilation on FreeBSD i386
if ! [ "$TARGET_OS" = FreeBSD -a "$TARGET_ARCHITECTURE" = i386 ]; then
  # Test whether -Wshorten-64-to-32 is available
  $CXX $CFLAGS -x c++ - -o /dev/null -Wshorten-64-to-32 2>/dev/null  <<EOF
    int main() {}
EOF
  if [ "$?" = 0 ]; then
    COMMON_FLAGS="$COMMON_FLAGS -Wshorten-64-to-32"
  fi
fi

USE_SSE=1
if [ "$TARGET_OS" = FreeBSD -a "$TARGET_ARCHITECTURE" = i386 ]; then
  # Intel SSE instructions breaks compilation on FreeBSD i386
  unset USE_SSE
fi

if test "$USE_SSE"; then
  # if Intel SSE instruction set is supported, set USE_SSE=1
  COMMON_FLAGS="$COMMON_FLAGS -msse -msse4.2 "
elif test -z "$PORTABLE"; then
  if test -n "`echo $TARGET_ARCHITECTURE | grep ^ppc64`"; then
    # Tune for this POWER processor, treating '+' models as base models
    POWER=`LD_SHOW_AUXV=1 /bin/true | grep AT_PLATFORM | grep -E -o power[0-9]+`
    COMMON_FLAGS="$COMMON_FLAGS -mcpu=$POWER -mtune=$POWER "
  elif test -n "`echo $TARGET_ARCHITECTURE | grep ^s390x`"; then
    COMMON_FLAGS="$COMMON_FLAGS -march=z10 "
  else
    COMMON_FLAGS="$COMMON_FLAGS -march=native "
  fi
fi

PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"

echo "CC=$CC" >> "$OUTPUT"
echo "CXX=$CXX" >> "$OUTPUT"
echo "PLATFORM=$PLATFORM" >> "$OUTPUT"
echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> "$OUTPUT"
echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> "$OUTPUT"
echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> "$OUTPUT"
echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> "$OUTPUT"
echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> "$OUTPUT"
echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> "$OUTPUT"
echo "PLATFORM_SHARED_VERSIONED=$PLATFORM_SHARED_VERSIONED" >> "$OUTPUT"
echo "PROFILING_FLAGS=$PROFILING_FLAGS" >> "$OUTPUT"