monero/cmake/FindCcache.cmake

# Copyright (c) 2014-2020, The Monero Project
#
# All rights reserved.
#
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# permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this list of
#    conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright notice, this list
#    of conditions and the following disclaimer in the documentation and/or other
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#    prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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# THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# - Try to find readline include dirs and libraries 
#
# Automatically finds ccache build accelerator, if it's found in PATH.
#
# Usage of this module as follows:
#
#     project(monero)
#     include(FindCcache) # Include AFTER the project() macro to be able to reach the CMAKE_CXX_COMPILER variable
#
# Properties modified by this module:
#
#  GLOBAL PROPERTY RULE_LAUNCH_COMPILE     set to ccache, when ccache found
#  GLOBAL PROPERTY RULE_LAUNCH_LINK        set to ccache, when ccache found

find_program(CCACHE_FOUND ccache)
if (CCACHE_FOUND)
	# Try to compile a test program with ccache, in order to verify if it really works. (needed on exotic setups)
	# Create a temporary file with a simple program.
	set(TEMP_CPP_FILE "${CMAKE_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/CMakeTmp/test-program.cpp")
	file(WRITE "${TEMP_CPP_FILE}" "int main() { return 0; }")
	# And run the found ccache on it.
	execute_process(COMMAND "${CCACHE_FOUND}" "${CMAKE_CXX_COMPILER}" "${TEMP_CPP_FILE}"  RESULT_VARIABLE RET)
	if (${RET} EQUAL 0)
		# Success
		message(STATUS "Found usable ccache: ${CCACHE_FOUND}")
		set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "${CCACHE_FOUND}")
		set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK    "${CCACHE_FOUND}")
	else()
		message(STATUS "Found ccache ${CCACHE_FOUND}, but is UNUSABLE! Return code: ${RET}")
	endif()
else()
	message(STATUS "ccache NOT found! Please install it for faster rebuilds.")
endif()