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authorEgor Tensin <Egor.Tensin@gmail.com>2021-03-14 19:03:20 +0300
committerEgor Tensin <Egor.Tensin@gmail.com>2021-03-14 19:03:20 +0300
commit53701adc9afa2d31020a9306a54c5ed58f71b948 (patch)
tree828ddb9d29977841ceb4f4e4d21ac4d692a53181 /project/cmake/toolchain.py
parentremove toolchains/ (diff)
downloadcmake-common-53701adc9afa2d31020a9306a54c5ed58f71b948.tar.gz
cmake-common-53701adc9afa2d31020a9306a54c5ed58f71b948.zip
move large in-code comments to docs/
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-rw-r--r--project/cmake/toolchain.py114
1 files changed, 1 insertions, 113 deletions
diff --git a/project/cmake/toolchain.py b/project/cmake/toolchain.py
index c2e54a6..14197aa 100644
--- a/project/cmake/toolchain.py
+++ b/project/cmake/toolchain.py
@@ -3,119 +3,7 @@
# For details, see https://github.com/egor-tensin/cmake-common.
# Distributed under the MIT License.
-# Default generator
-# -----------------
-#
-# As of CMake 3.18, the default generator (unless set explicitly) is:
-# * the newest Visual Studio or "NMake Makefiles" on Windows,
-# * "Unix Makefiles" otherwise.
-# This is regardless of whether any executables like gcc, cl or make are
-# available [1].
-#
-# Makefile generators
-# -------------------
-#
-# CMake has a number of "... Makefiles" generators. "Unix Makefiles" uses
-# gmake/make/smake, whichever is found first, and cc/c++ for compiler
-# detection [2]. "MinGW Makefiles" looks for mingw32-make.exe in a number of
-# well-known locations, uses gcc/g++ directly, and is aware of windres [3]. In
-# addition, "Unix Makefiles" uses /bin/sh as the SHELL value in the Makefile,
-# while the MinGW version uses cmd.exe. I don't think it matters on Windows
-# though, since the non-existent /bin/sh is ignored anyway [4]. "NMake
-# Makefiles" is similar, except it defaults to using cl [5].
-#
-# It's important to _not_ use the -A parameter with any of the Makefile
-# generators - it's an error. This goes for "NMake Makefiles" also. "NMake
-# Makefiles" doesn't attempt to search for installed Visual Studio compilers,
-# you need to use it from one of the Visual Studio-provided shells.
-#
-# Visual Studio generators
-# ------------------------
-#
-# These are special. They ignore the CMAKE_<LANG>_COMPILER parameters and use
-# cl by default [9]. They support specifying the toolset to use via the -T
-# parameter (the "Platform Toolset" value in the project's properties) since
-# 3.18 [10]. The toolset list varies between Visual Studio versions, and I'm
-# too lazy to learn exactly which version supports which toolsets.
-#
-# cmake --build uses msbuild with Visual Studio generators. You can pass the
-# path to a different cl.exe by doing something like
-#
-# msbuild ... /p:CLToolExe=another-cl.exe /p:CLToolPath=C:\parent\dir
-#
-# It's important that the generators for Visual Studio 2017 or older use Win32
-# Win32 as the default platform [12]. Because of that, we need to pass the -A
-# parameter.
-#
-# mingw32-make vs make
-# --------------------
-#
-# No idea what the actual differences are. The explanation in the FAQ [6]
-# about how GNU make "is lacking in some functionality and has modified
-# functionality due to the lack of POSIX on Win32" isn't terribly helpful.
-#
-# It's important that you can install either on Windows (`choco install make`
-# for GNU make and `choco install mingw` to install a MinGW-w64 distribution
-# with mingw32-make.exe included). Personally, I don't see any difference
-# between using either make.exe or mingw32-make.exe w/ CMake on Windows. But,
-# since MinGW-w64 distributions do include mingw32-make.exe and not make.exe,
-# we'll try to detect that.
-#
-# Cross-compilation
-# -----------------
-#
-# If you want to e.g. build x86 binary on x64 and vice versa, the easiest way
-# seems to be to make a CMake "toolchain file", which initializes the proper
-# compiler flags (like -m64/-m32, etc.). Such file could look like this:
-#
-# set(CMAKE_C_COMPILER gcc)
-# set(CMAKE_C_FLAGS -m32)
-# set(CMAKE_CXX_COMPILER g++)
-# set(CMAKE_CXX_FLAGS -m32)
-#
-# You can then pass the path to it using the CMAKE_TOOLCHAIN_FILE parameter.
-#
-# If you use the Visual Studio generators, just use the -A parameter, like "-A
-# Win32".
-#
-# As a side note, if you want to cross-compile between x86 and x64 using GCC on
-# Ubuntu, you need to install the gcc-multilib package.
-#
-# Windows & Clang
-# ---------------
-#
-# Using Clang on Windows is no easy task, of course. Prior to 3.15, there was
-# no support for building things using the clang++.exe executable, only
-# clang-cl.exe was supported [7]. If you specified -DCMAKE_CXX_COMPILER=clang++,
-# CMake would stil pass MSVC-style command line options to the compiler (like
-# /MD, /nologo, etc.), which clang++ doesn't like [8].
-#
-# So, in summary, you can only use clang++ since 3.15. clang-cl doesn't work
-# with Visual Studio generators unless you specify the proper toolset using the
-# -T parameter. You can set the ClToolExe property using msbuild, but while
-# that might work in practice, clang-cl.exe needs to map some unsupported
-# options for everything to work properly. For an example of how this is done,
-# see the LLVM.Cpp.Common.* files at [11].
-#
-# I recommend using Clang (either clang-cl or clang++ since 3.15) using the
-# "NMake Makefiles" generator.
-#
-# References
-# ----------
-#
-# [1]: cmake::EvaluateDefaultGlobalGenerator
-# https://github.com/Kitware/CMake/blob/v3.18.4/Source/cmake.cxx
-# [2]: https://github.com/Kitware/CMake/blob/v3.18.4/Source/cmGlobalUnixMakefileGenerator3.cxx
-# [3]: https://github.com/Kitware/CMake/blob/v3.18.4/Source/cmGlobalMinGWMakefileGenerator.cxx
-# [4]: https://www.gnu.org/software/make/manual/html_node/Choosing-the-Shell.html
-# [5]: https://github.com/Kitware/CMake/blob/v3.18.4/Source/cmGlobalNMakeMakefileGenerator.cxx
-# [6]: http://mingw.org/wiki/FAQ
-# [7]: https://cmake.org/cmake/help/v3.15/release/3.15.html#compilers
-# [8]: https://github.com/Kitware/CMake/blob/v3.14.7/Modules/Platform/Windows-Clang.cmake
-# [9]: https://gitlab.kitware.com/cmake/cmake/-/issues/19174
-# [10]: https://cmake.org/cmake/help/v3.8/release/3.8.html
-# [11]: https://github.com/llvm/llvm-project/tree/e408935bb5339e20035d84307c666fbdd15e99e0/llvm/tools/msbuild
-# [12]: https://cmake.org/cmake/help/v3.18/generator/Visual%20Studio%2015%202017.html
+# See docs/cmake.md for a more thorough description of my pain.
import abc
import os.path