CMake/Modules/CMakeDetermineCCompiler.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names and years are hard to maintain and often out-of-date or plain wrong.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

180 lines
6.5 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
# determine the compiler to use for C programs
# NOTE, a generator may set CMAKE_C_COMPILER before
# loading this file to force a compiler.
# use environment variable CC first if defined by user, next use
# the cmake variable CMAKE_GENERATOR_CC which can be defined by a generator
# as a default compiler
# If the internal cmake variable _CMAKE_TOOLCHAIN_PREFIX is set, this is used
# as prefix for the tools (e.g. arm-elf-gcc, arm-elf-ar etc.). This works
# currently with the GNU crosscompilers.
#
# Sets the following variables:
# CMAKE_C_COMPILER
# CMAKE_AR
# CMAKE_RANLIB
# CMAKE_COMPILER_IS_GNUCC
#
# If not already set before, it also sets
# _CMAKE_TOOLCHAIN_PREFIX
include(${CMAKE_ROOT}/Modules/CMakeDetermineCompiler.cmake)
# Load system-specific compiler preferences for this language.
include(Platform/${CMAKE_SYSTEM_NAME}-Determine-C OPTIONAL)
include(Platform/${CMAKE_SYSTEM_NAME}-C OPTIONAL)
if(NOT CMAKE_C_COMPILER_NAMES)
set(CMAKE_C_COMPILER_NAMES cc)
endif()
if(${CMAKE_GENERATOR} MATCHES "Visual Studio")
elseif("${CMAKE_GENERATOR}" MATCHES "Xcode")
set(CMAKE_C_COMPILER_XCODE_TYPE sourcecode.c.c)
_cmake_find_compiler_path(C)
else()
if(NOT CMAKE_C_COMPILER)
set(CMAKE_C_COMPILER_INIT NOTFOUND)
# prefer the environment variable CC
if(NOT $ENV{CC} STREQUAL "")
get_filename_component(CMAKE_C_COMPILER_INIT $ENV{CC} PROGRAM PROGRAM_ARGS CMAKE_C_FLAGS_ENV_INIT)
if(CMAKE_C_FLAGS_ENV_INIT)
set(CMAKE_C_COMPILER_ARG1 "${CMAKE_C_FLAGS_ENV_INIT}" CACHE STRING "First argument to C compiler")
endif()
if(NOT EXISTS ${CMAKE_C_COMPILER_INIT})
message(FATAL_ERROR "Could not find compiler set in environment variable CC:\n$ENV{CC}.")
endif()
endif()
# next try prefer the compiler specified by the generator
if(CMAKE_GENERATOR_CC)
if(NOT CMAKE_C_COMPILER_INIT)
set(CMAKE_C_COMPILER_INIT ${CMAKE_GENERATOR_CC})
endif()
endif()
# finally list compilers to try
if(NOT CMAKE_C_COMPILER_INIT)
set(CMAKE_C_COMPILER_LIST ${_CMAKE_TOOLCHAIN_PREFIX}cc ${_CMAKE_TOOLCHAIN_PREFIX}gcc cl bcc xlc clang)
endif()
_cmake_find_compiler(C)
else()
_cmake_find_compiler_path(C)
endif()
mark_as_advanced(CMAKE_C_COMPILER)
# Each entry in this list is a set of extra flags to try
# adding to the compile line to see if it helps produce
# a valid identification file.
set(CMAKE_C_COMPILER_ID_TEST_FLAGS_FIRST)
set(CMAKE_C_COMPILER_ID_TEST_FLAGS
# Try compiling to an object file only.
"-c"
# Try enabling ANSI mode on HP.
"-Aa"
# Try compiling K&R-compatible code (needed by Bruce C Compiler).
"-D__CLASSIC_C__"
)
endif()
# Build a small source file to identify the compiler.
if(NOT CMAKE_C_COMPILER_ID_RUN)
set(CMAKE_C_COMPILER_ID_RUN 1)
# Try to identify the compiler.
set(CMAKE_C_COMPILER_ID)
set(CMAKE_C_PLATFORM_ID)
file(READ ${CMAKE_ROOT}/Modules/CMakePlatformId.h.in
CMAKE_C_COMPILER_ID_PLATFORM_CONTENT)
# The IAR compiler produces weird output.
# See https://gitlab.kitware.com/cmake/cmake/issues/10176#note_153591
list(APPEND CMAKE_C_COMPILER_ID_VENDORS IAR)
set(CMAKE_C_COMPILER_ID_VENDOR_FLAGS_IAR )
set(CMAKE_C_COMPILER_ID_VENDOR_REGEX_IAR "IAR .+ Compiler")
# Match the link line from xcodebuild output of the form
# Ld ...
# ...
# /path/to/cc ...CompilerIdC/...
# to extract the compiler front-end for the language.
set(CMAKE_C_COMPILER_ID_TOOL_MATCH_REGEX "\nLd[^\n]*(\n[ \t]+[^\n]*)*\n[ \t]+([^ \t\r\n]+)[^\r\n]*-o[^\r\n]*CompilerIdC/(\\./)?(CompilerIdC.xctest/)?CompilerIdC[ \t\n\\\"]")
set(CMAKE_C_COMPILER_ID_TOOL_MATCH_INDEX 2)
include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerId.cmake)
CMAKE_DETERMINE_COMPILER_ID(C CFLAGS CMakeCCompilerId.c)
# Set old compiler and platform id variables.
if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
set(CMAKE_COMPILER_IS_GNUCC 1)
endif()
if(CMAKE_C_PLATFORM_ID MATCHES "MinGW")
set(CMAKE_COMPILER_IS_MINGW 1)
elseif(CMAKE_C_PLATFORM_ID MATCHES "Cygwin")
set(CMAKE_COMPILER_IS_CYGWIN 1)
endif()
endif()
if (NOT _CMAKE_TOOLCHAIN_LOCATION)
get_filename_component(_CMAKE_TOOLCHAIN_LOCATION "${CMAKE_C_COMPILER}" PATH)
endif ()
# If we have a gcc cross compiler, they have usually some prefix, like
# e.g. powerpc-linux-gcc, arm-elf-gcc or i586-mingw32msvc-gcc, optionally
# with a 3-component version number at the end (e.g. arm-eabi-gcc-4.5.2).
# The other tools of the toolchain usually have the same prefix
# NAME_WE cannot be used since then this test will fail for names like
# "arm-unknown-nto-qnx6.3.0-gcc.exe", where BASENAME would be
# "arm-unknown-nto-qnx6" instead of the correct "arm-unknown-nto-qnx6.3.0-"
if (CMAKE_CROSSCOMPILING AND NOT _CMAKE_TOOLCHAIN_PREFIX)
if(CMAKE_C_COMPILER_ID MATCHES "GNU" OR CMAKE_C_COMPILER_ID MATCHES "Clang")
get_filename_component(COMPILER_BASENAME "${CMAKE_C_COMPILER}" NAME)
if (COMPILER_BASENAME MATCHES "^(.+-)(clang|g?cc)(-[0-9]+\\.[0-9]+\\.[0-9]+)?(\\.exe)?$")
set(_CMAKE_TOOLCHAIN_PREFIX ${CMAKE_MATCH_1})
elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
if(CMAKE_C_COMPILER_TARGET)
set(_CMAKE_TOOLCHAIN_PREFIX ${CMAKE_C_COMPILER_TARGET}-)
endif()
elseif(COMPILER_BASENAME MATCHES "qcc(\\.exe)?$")
if(CMAKE_C_COMPILER_TARGET MATCHES "gcc_nto([^_le]+)(le)?")
set(_CMAKE_TOOLCHAIN_PREFIX nto${CMAKE_MATCH_1}-)
endif()
endif ()
# if "llvm-" is part of the prefix, remove it, since llvm doesn't have its own binutils
# but uses the regular ar, objcopy, etc. (instead of llvm-objcopy etc.)
if ("${_CMAKE_TOOLCHAIN_PREFIX}" MATCHES "(.+-)?llvm-$")
set(_CMAKE_TOOLCHAIN_PREFIX ${CMAKE_MATCH_1})
endif ()
elseif(CMAKE_C_COMPILER_ID MATCHES "TI")
# TI compilers are named e.g. cl6x, cl470 or armcl.exe
get_filename_component(COMPILER_BASENAME "${CMAKE_C_COMPILER}" NAME)
if (COMPILER_BASENAME MATCHES "^(.+)?cl([^.]+)?(\\.exe)?$")
set(_CMAKE_TOOLCHAIN_PREFIX "${CMAKE_MATCH_1}")
set(_CMAKE_TOOLCHAIN_SUFFIX "${CMAKE_MATCH_2}")
endif ()
endif()
endif ()
include(CMakeFindBinUtils)
if(MSVC_C_ARCHITECTURE_ID)
set(SET_MSVC_C_ARCHITECTURE_ID
"set(MSVC_C_ARCHITECTURE_ID ${MSVC_C_ARCHITECTURE_ID})")
endif()
# configure variables set in this file for fast reload later on
configure_file(${CMAKE_ROOT}/Modules/CMakeCCompiler.cmake.in
${CMAKE_PLATFORM_INFO_DIR}/CMakeCCompiler.cmake
@ONLY
)
set(CMAKE_C_COMPILER_ENV_VAR "CC")