Display default compiler symbols

showdefines.bash

#!/bin/bash

# showdefines.bash: display default compiler symbols.
# Copyright © 2011,2017, Ramsey Dow. All rights reserved.
# SPDX-License-Identifier: BSD-2-Clause

# Usage: showdefines.bash [-c compiler] [-l language] [additional flags ...]
# Defaults to clang++, but works fine with C and groks the GNU and Intel compilers, as well.

# http://clang.llvm.org/
# http://gcc.gnu.org/
# http://software.intel.com/en-us/articles/intel-compilers/

script=$(basename "$0" '.bash')
compiler=clang
language=c++
tempfile=/tmp/$$.c

function usage {
  echo "Usage: $script [-c clang|clang++|gcc|g++|icc|i++] [-l c|c++]"
	exit 1
}

OPTERR=0
while getopts 'c:l:' opt; do
  case "$opt" in
    c) compiler=$OPTARG ;;
    l) language=$OPTARG ;;
    \?) usage ;;
  esac
done

case $compiler in
	clang|clang++) # LLVM Clang compiler
    flags='-dM -E'
    ;;
	gcc|g++) # GNU compiler Collection
    flags='-dM -E'
    ;;
	icc|i++) # Intel compiler
    flags='-dM -E'
    ;;
	*) echo "${script}: ${1}: unrecognized compiler"
    exit 1
    ;;
esac

case $language in
	c++) if [ "$compiler" = "clang" ]; then
      compiler=clang++
      all_flags="$flags -x $language"
    elif [ "$compiler" = "gcc" ]; then
      compiler=g++
      all_flags=$flags
    elif [ "$compiler" = "icc" ]; then
      compiler=i++
      all_flags="$flags -x $language"
    fi
    ;;
	*) echo "${script}: unsupported langage ${language}"
    exit 1
    ;;
esac

case $compiler in
	clang|clang++) # shellcheck disable=SC2086
    $compiler $all_flags /dev/null
    ;;
	gcc|g++) # shellcheck disable=SC2086
    touch $tempfile && $compiler $flags "$@" $tempfile && rm -f $tempfile
    ;;
	icc|i++) # shellcheck disable=SC2086
    touch $tempfile && $compiler $flags "$@" $tempfile && rm -f $tempfile
    ;;
esac

exit 0