Arduino CMake

#Copyright (C) 2011  Devin DeLong
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.


# This module defines macros intended for use by cross-compiling toolchain files when
# CMake is not able to automatically detect the compiler identification.
include (CMakeForceCompiler)

# Set this for cross compiling.  Otherwise it is set to CMAKE_HOST_SYSTEM_NAME,
# which is the system we are developing on.
set (CMAKE_SYSTEM_NAME Generic)

# It sets CMAKE_<lang>_COMPILER to the given compiler and the cmake internal variable
# CMAKE_<lang>_COMPILER_ID to the given compiler-id. It also bypasses the check for
# working compiler and basic compiler information tests.
cmake_force_cxx_compiler (avr-g++ CrossAVR)
cmake_force_c_compiler (avr-gcc CrossAVR)

# Appparently we want to use the gnuc99 standard.
set (CSTANDARD "-std=gnu99")

# Generate .stabs debugging symbols for assembler source lines. This enables avr-gdb to
# trace through assembler source files.
set (CDEBUG "-gstabs")

# Warn for functions declared or defined without specified argument types.
set (CWARN "-Wall -Wstrict-prototypes")

# -funsigned-char - Make any unqualfied char type an unsigned char. Without this option,
#   they default to a signed char.
# -funsigned-bitfields - Make any unqualified bitfield type unsigned. By default,
#    they are signed.
# -fpack-struct - Pack all structure members together without holes.
# -fshort-enums - Allocate to an enum type only as many bytes as it needs for the declared
#   range of possible values. Specifically, the enum type will be equivalent to the
#   smallest integer type which has enough room.
set (CTUNING_FLAGS "-funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums")

# Optimize for size.   The special option -Os is meant to turn on all -O2 optimizations
# that are not expected to increase code size.
set (COPT "-Os")

# Finally the compilation flags are now configured.
set(CMAKE_CXX_FLAGS "-mmcu=${ARDUINO_PROCESSOR} -DF_CPU=${ARDUINO_PROCESSOR_FREQ} ${COPT}")
set(CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS} ${CTUNING_FLAGS} ${CWARN} ${CSTANDARD} ${CDEBUG}")

# On gentoo, -rdynamic is passed to the compiler. The avr compiler does not recognize this
# option.  Also, we are not building shared libraries.
set(CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS "")