CMake/Modules/CMakeDetermineCompiler.cmake
Brad King 86578eccf2 Simplify CMake per-source license notices
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool.  Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience.  Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.

Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices.  It also references version control
history for more precise information.  Therefore we no longer need to spell
out the list of Contributors in each source file notice.

Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing".  The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.

Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically.  Manually fix up shebang lines and trailing
newlines in a few files.  Manually update the notices in a few files that the
script does not handle.
2016-09-27 15:14:44 -04:00

121 lines
4.9 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
macro(_cmake_find_compiler lang)
# Use already-enabled languages for reference.
get_property(_languages GLOBAL PROPERTY ENABLED_LANGUAGES)
list(REMOVE_ITEM _languages "${lang}")
if(CMAKE_${lang}_COMPILER_INIT)
# Search only for the specified compiler.
set(CMAKE_${lang}_COMPILER_LIST "${CMAKE_${lang}_COMPILER_INIT}")
else()
# Re-order the compiler list with preferred vendors first.
set(_${lang}_COMPILER_LIST "${CMAKE_${lang}_COMPILER_LIST}")
set(CMAKE_${lang}_COMPILER_LIST "")
# Prefer vendors of compilers from reference languages.
foreach(l ${_languages})
list(APPEND CMAKE_${lang}_COMPILER_LIST
${_${lang}_COMPILER_NAMES_${CMAKE_${l}_COMPILER_ID}})
endforeach()
# Prefer vendors based on the platform.
list(APPEND CMAKE_${lang}_COMPILER_LIST ${CMAKE_${lang}_COMPILER_NAMES})
# Append the rest of the list and remove duplicates.
list(APPEND CMAKE_${lang}_COMPILER_LIST ${_${lang}_COMPILER_LIST})
unset(_${lang}_COMPILER_LIST)
list(REMOVE_DUPLICATES CMAKE_${lang}_COMPILER_LIST)
if(CMAKE_${lang}_COMPILER_EXCLUDE)
list(REMOVE_ITEM CMAKE_${lang}_COMPILER_LIST
${CMAKE_${lang}_COMPILER_EXCLUDE})
endif()
endif()
# Look for directories containing compilers of reference languages.
set(_${lang}_COMPILER_HINTS)
foreach(l ${_languages})
if(CMAKE_${l}_COMPILER AND IS_ABSOLUTE "${CMAKE_${l}_COMPILER}")
get_filename_component(_hint "${CMAKE_${l}_COMPILER}" PATH)
if(IS_DIRECTORY "${_hint}")
list(APPEND _${lang}_COMPILER_HINTS "${_hint}")
endif()
unset(_hint)
endif()
endforeach()
# Find the compiler.
if(_${lang}_COMPILER_HINTS)
# Prefer directories containing compilers of reference languages.
list(REMOVE_DUPLICATES _${lang}_COMPILER_HINTS)
find_program(CMAKE_${lang}_COMPILER
NAMES ${CMAKE_${lang}_COMPILER_LIST}
PATHS ${_${lang}_COMPILER_HINTS}
NO_DEFAULT_PATH
DOC "${lang} compiler")
endif()
find_program(CMAKE_${lang}_COMPILER NAMES ${CMAKE_${lang}_COMPILER_LIST} DOC "${lang} compiler")
if(CMAKE_${lang}_COMPILER_INIT AND NOT CMAKE_${lang}_COMPILER)
set_property(CACHE CMAKE_${lang}_COMPILER PROPERTY VALUE "${CMAKE_${lang}_COMPILER_INIT}")
endif()
unset(_${lang}_COMPILER_HINTS)
unset(_languages)
# Look for a make tool provided by Xcode
if(CMAKE_HOST_APPLE)
macro(_query_xcrun compiler_name result_var_keyword result_var)
if(NOT "x${result_var_keyword}" STREQUAL "xRESULT_VAR")
message(FATAL_ERROR "Bad arguments to macro")
endif()
execute_process(COMMAND xcrun --find ${compiler_name}
OUTPUT_VARIABLE _xcrun_out OUTPUT_STRIP_TRAILING_WHITESPACE
ERROR_VARIABLE _xcrun_err)
set("${result_var}" "${_xcrun_out}")
endmacro()
set(xcrun_result)
if (CMAKE_${lang}_COMPILER MATCHES "^/usr/bin/(.+)$")
_query_xcrun("${CMAKE_MATCH_1}" RESULT_VAR xcrun_result)
elseif (CMAKE_${lang}_COMPILER STREQUAL "CMAKE_${lang}_COMPILER-NOTFOUND")
foreach(comp ${CMAKE_${lang}_COMPILER_LIST})
_query_xcrun("${comp}" RESULT_VAR xcrun_result)
if(xcrun_result)
break()
endif()
endforeach()
endif()
if (xcrun_result)
set_property(CACHE CMAKE_${lang}_COMPILER PROPERTY VALUE "${xcrun_result}")
endif()
endif()
endmacro()
macro(_cmake_find_compiler_path lang)
if(CMAKE_${lang}_COMPILER)
# we only get here if CMAKE_${lang}_COMPILER was specified using -D or a pre-made CMakeCache.txt
# (e.g. via ctest) or set in CMAKE_TOOLCHAIN_FILE
# if CMAKE_${lang}_COMPILER is a list of length 2, use the first item as
# CMAKE_${lang}_COMPILER and the 2nd one as CMAKE_${lang}_COMPILER_ARG1
list(LENGTH CMAKE_${lang}_COMPILER _CMAKE_${lang}_COMPILER_LIST_LENGTH)
if("${_CMAKE_${lang}_COMPILER_LIST_LENGTH}" EQUAL 2)
list(GET CMAKE_${lang}_COMPILER 1 CMAKE_${lang}_COMPILER_ARG1)
list(GET CMAKE_${lang}_COMPILER 0 CMAKE_${lang}_COMPILER)
endif()
unset(_CMAKE_${lang}_COMPILER_LIST_LENGTH)
# find the compiler in the PATH if necessary
get_filename_component(_CMAKE_USER_${lang}_COMPILER_PATH "${CMAKE_${lang}_COMPILER}" PATH)
if(NOT _CMAKE_USER_${lang}_COMPILER_PATH)
find_program(CMAKE_${lang}_COMPILER_WITH_PATH NAMES ${CMAKE_${lang}_COMPILER})
if(CMAKE_${lang}_COMPILER_WITH_PATH)
set(CMAKE_${lang}_COMPILER ${CMAKE_${lang}_COMPILER_WITH_PATH})
get_property(_CMAKE_${lang}_COMPILER_CACHED CACHE CMAKE_${lang}_COMPILER PROPERTY TYPE)
if(_CMAKE_${lang}_COMPILER_CACHED)
set(CMAKE_${lang}_COMPILER "${CMAKE_${lang}_COMPILER}" CACHE STRING "${lang} compiler" FORCE)
endif()
unset(_CMAKE_${lang}_COMPILER_CACHED)
endif()
unset(CMAKE_${lang}_COMPILER_WITH_PATH CACHE)
endif()
endif()
endmacro()