Makefile

#This is a simple wrapper hiding cmake from non-expert end users.
#
# It supports the targets:
#   'make' 		 	 - builds everything (all libaries/executables)
#   'make clean' 	 - removes generated build objects/libraries/executables etc.
# 	'make distclean' - will clean everything including the cmake generated build files
#
# All other targets (e.g. 'make vpr') are passed to the cmake generated makefile
# and processed according to the CMakeLists.txt.
#
# To perform a debug build use:
#   'make BUILD_TYPE=debug'

#Default build type
# Possible values:
#    release
#    debug
BUILD_TYPE = release

#Allows users to pass parameters to cmake
#  e.g. make CMAKE_PARAMS="-DVTR_ENABLE_SANITIZE=true"
override CMAKE_PARAMS += -DCMAKE_BUILD_TYPE=$(BUILD_TYPE)

#Suppress makefile output (e.g. entering/leaving directories)
MAKEFLAGS := -s 

BUILD_DIR=./build
GENERATED_MAKEFILE := $(BUILD_DIR)/Makefile

#Check for the cmake exectuable
CMAKE := $(shell command -v cmake 2> /dev/null)


#All targets in this make file are always out of date.
# This ensures that any make target requests are forwarded to
# the generated makefile
.PHONY: all distclean $(GENERATED_MAKEFILE) $(MAKECMDGOALS)

#Build everything
all: $(GENERATED_MAKEFILE)
	@+$(MAKE) -C $(BUILD_DIR)

#Call the generated Makefile's clean, and then remove all cmake generated files
distclean: $(GENERATED_MAKEFILE)
	@ echo "Cleaning build..."
	@+$(MAKE) -C $(BUILD_DIR) clean 
	@ echo "Removing build system files.."
	@ rm -rf $(BUILD_DIR)
	@ rm -rf CMakeFiles CMakeCache.txt #In case 'cmake .' was run in the source directory

#Call cmake to generate the main Makefile
$(GENERATED_MAKEFILE):
ifndef CMAKE
	$(error Required 'cmake' executable not found. On debian/ubuntu try 'sudo apt-get install cmake' to install)
endif
	@ mkdir -p $(BUILD_DIR)
	echo "cd $(BUILD_DIR) && $(CMAKE) $(CMAKE_PARAMS) .. "
	cd $(BUILD_DIR) && $(CMAKE) $(CMAKE_PARAMS) .. 

#Forward any targets that are not named 'distclean' to the generated Makefile
ifeq ($(findstring distclean,$(MAKECMDGOALS)),)
$(MAKECMDGOALS): $(GENERATED_MAKEFILE)
	@+$(MAKE) -C $(BUILD_DIR) $(MAKECMDGOALS)
endif