CMAKE_SYSTEM_VERSION for CMake builds
#30465
From CMake docs:
When the CMAKE_SYSTEM_NAME variable is set explicitly to enable cross compiling then the value of CMAKE_SYSTEM_VERSION must also be set explicitly to specify the target system version.
This PR is split from #30454 and improves the current depends build subsystem.
The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.
For detailed information about the code coverage, see the test coverage report.
See the guideline for information on the review process.
| Type | Reviewers |
|---|---|
| ACK | pablomartin4btc, vasild |
| Concept ACK | theuni |
If your review is incorrectly listed, please react with 👎 to this comment and the bot will ignore it on the next update.
Reviewers, this pull request conflicts with the following ones:
x86_64-linux-gnu release binaries as CET-enabled by hebasto)If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.
My Guix build:
0x86_64
1460732347ffc71500f84d1174f6a6011b887681e82fc1704c1187cb1701bf9af guix-build-5ff8074361e9/output/aarch64-linux-gnu/SHA256SUMS.part
2b084b5371e3acff1850c8f3234299f99c3635fd497919f28407acaee27322877 guix-build-5ff8074361e9/output/aarch64-linux-gnu/bitcoin-5ff8074361e9-aarch64-linux-gnu-debug.tar.gz
39f0f40cb3510197338efca2c7423fb7615a34a8b21a90c500c7fa45898875a9d guix-build-5ff8074361e9/output/aarch64-linux-gnu/bitcoin-5ff8074361e9-aarch64-linux-gnu.tar.gz
4b571a25f1cf2c5f282342667823cdb5ed632e4b549361a46853414987091b1ce guix-build-5ff8074361e9/output/arm-linux-gnueabihf/SHA256SUMS.part
5758328c887a3b1233ff96c6ca867ad1e05cfbde376b17197ef69318307e19b9f guix-build-5ff8074361e9/output/arm-linux-gnueabihf/bitcoin-5ff8074361e9-arm-linux-gnueabihf-debug.tar.gz
66628127da8fa423f23af5171f2e03b9afce5f579a08c4416de0cc8302fe841b6 guix-build-5ff8074361e9/output/arm-linux-gnueabihf/bitcoin-5ff8074361e9-arm-linux-gnueabihf.tar.gz
7ead35c171f2b8a00d7755a8a18811ef3ee0567952b42c8a0de0a5647cd566a34 guix-build-5ff8074361e9/output/arm64-apple-darwin/SHA256SUMS.part
8b872260bf88b6affc5c53fd0d0fa1aac7edb458902358cf64a6117dd0ecc29e0 guix-build-5ff8074361e9/output/arm64-apple-darwin/bitcoin-5ff8074361e9-arm64-apple-darwin-unsigned.tar.gz
9443ff94fa3129b7e54ed58291d06fa708e812aa3b07937f9b8b9bcac9d93538c guix-build-5ff8074361e9/output/arm64-apple-darwin/bitcoin-5ff8074361e9-arm64-apple-darwin-unsigned.zip
100c84027d40ee433eaf064f5198a6eaf01ade9cd5c75cc6534c8dc1ecedb89bd1 guix-build-5ff8074361e9/output/arm64-apple-darwin/bitcoin-5ff8074361e9-arm64-apple-darwin.tar.gz
119853a449e72c2e2b641b9f976d50b2d72a4a07876c25ba75812667a37366014a guix-build-5ff8074361e9/output/dist-archive/bitcoin-5ff8074361e9.tar.gz
12aee54f6d0e991040a02bd81d98d6034be922492dacd8275e6857a350be1628a1 guix-build-5ff8074361e9/output/powerpc64-linux-gnu/SHA256SUMS.part
139a9de9a7cd9fdd78552f59ffd812831e508b9c9a98125c8117168ad620f54eb5 guix-build-5ff8074361e9/output/powerpc64-linux-gnu/bitcoin-5ff8074361e9-powerpc64-linux-gnu-debug.tar.gz
144ce3ba8f2684bdf3c0821448f79b30bdc7cd6f30b6d403eb1a156b3cbaab8f88 guix-build-5ff8074361e9/output/powerpc64-linux-gnu/bitcoin-5ff8074361e9-powerpc64-linux-gnu.tar.gz
157feb0a0f3a830929dca504284478d0ab77cde22312fc695bdd4052a093084104 guix-build-5ff8074361e9/output/riscv64-linux-gnu/SHA256SUMS.part
16f62b2b2d9a407bcef69a714fad8141f360da3edf05a431017f88157b2da4b916 guix-build-5ff8074361e9/output/riscv64-linux-gnu/bitcoin-5ff8074361e9-riscv64-linux-gnu-debug.tar.gz
17385007a5fa879d508e3802c2034920125ec292c8f2385cc9c76eba0081fe5426 guix-build-5ff8074361e9/output/riscv64-linux-gnu/bitcoin-5ff8074361e9-riscv64-linux-gnu.tar.gz
182d03dd96e90c66c4ae9f75bf799da63132df7738bdac8f1c5b32cc2627d9344a guix-build-5ff8074361e9/output/x86_64-apple-darwin/SHA256SUMS.part
196970c1003c5a635155dc2385169e4ac099a188cf448f55abaa82b94c8eaf961b guix-build-5ff8074361e9/output/x86_64-apple-darwin/bitcoin-5ff8074361e9-x86_64-apple-darwin-unsigned.tar.gz
20528a2da62a4312663de96166b82c37d361767eacc4c6e492d07282373110d2f1 guix-build-5ff8074361e9/output/x86_64-apple-darwin/bitcoin-5ff8074361e9-x86_64-apple-darwin-unsigned.zip
211ec8dc814de841757fdc45eb028d9df13f1b6f8e05f01642d76539920e16b400 guix-build-5ff8074361e9/output/x86_64-apple-darwin/bitcoin-5ff8074361e9-x86_64-apple-darwin.tar.gz
223691ba37e116c794860e7693c8b0f81e171319cc1e15f8cfc37a8336f1631dc1 guix-build-5ff8074361e9/output/x86_64-linux-gnu/SHA256SUMS.part
23e0811eb91bfe9661e9dd7fb5fb2848729b7295db5237a9cff39e4fc2add46bf2 guix-build-5ff8074361e9/output/x86_64-linux-gnu/bitcoin-5ff8074361e9-x86_64-linux-gnu-debug.tar.gz
24d9c2e29dd11f700b7ea1477e3c7564baf613ebdc5aa97e7ea6530d5115d5e95b guix-build-5ff8074361e9/output/x86_64-linux-gnu/bitcoin-5ff8074361e9-x86_64-linux-gnu.tar.gz
251e0a09cd5edaf1c1613c75fc978170b5166a2e6a2009bec48591f85626a7b908 guix-build-5ff8074361e9/output/x86_64-w64-mingw32/SHA256SUMS.part
260c2dbb9553e81f0e30778be60e7b17b4727ded5518161e90b539ba5069052474 guix-build-5ff8074361e9/output/x86_64-w64-mingw32/bitcoin-5ff8074361e9-win64-debug.zip
27f255226d5ecd3cfccfaa2b1f2c2ec98da015e47ddb08ef15339d6ea3fb9eb8ab guix-build-5ff8074361e9/output/x86_64-w64-mingw32/bitcoin-5ff8074361e9-win64-setup-unsigned.exe
28755903863b08594bba9ac52bb2a7e2e87ee077d0e8f777e7d9e768147fa9ce03 guix-build-5ff8074361e9/output/x86_64-w64-mingw32/bitcoin-5ff8074361e9-win64-unsigned.tar.gz
29aa3cceab8c14f99d278ee628193ca9b3ff51343a658dcbc7dd141ebeac8e2ae3 guix-build-5ff8074361e9/output/x86_64-w64-mingw32/bitcoin-5ff8074361e9-win64.zip
What change in behaviour should be expected here?
For example, when building for macOS, the CMAKE_SYSTEM_VERSION value is used to define DARWIN_MAJOR_VERSION and DARWIN_MINOR_VERSION, which in turn affect the default build options.
81@@ -82,3 +82,6 @@ darwin_debug_CFLAGS=-O1 -g
82 darwin_debug_CXXFLAGS=$(darwin_debug_CFLAGS)
83
84 darwin_cmake_system_name=Darwin
85+# Darwin version, which corresponds to OSX_MIN_VERSION.
86+# See https://en.wikipedia.org/wiki/Darwin_(operating_system)
87+darwin_cmake_system_version=20.1
OSX_MIN_VERSION? Ideally we’d compose these somehow.
Where/how does CMake translate this to
OSX_MIN_VERSION?
… the
CMAKE_SYSTEM_VERSIONvalue is used to defineDARWIN_MAJOR_VERSIONandDARWIN_MINOR_VERSION…
It happens here:
0# Darwin versions:
1# 6.x == Mac OSX 10.2 (Jaguar)
2# 7.x == Mac OSX 10.3 (Panther)
3# 8.x == Mac OSX 10.4 (Tiger)
4# 9.x == Mac OSX 10.5 (Leopard)
5# 10.x == Mac OSX 10.6 (Snow Leopard)
6# 11.x == Mac OSX 10.7 (Lion)
7# 12.x == Mac OSX 10.8 (Mountain Lion)
8string(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\1" DARWIN_MAJOR_VERSION "${CMAKE_SYSTEM_VERSION}")
9string(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\2" DARWIN_MINOR_VERSION "${CMAKE_SYSTEM_VERSION}")
The chosen Darwin version 20.1 is associated with macOS 11.0: https://github.com/bitcoin/bitcoin/blob/37992244e636e52e0c2baff1bc5f36e60d9c956f/depends/hosts/darwin.mk#L1
Concept ACK, but we need more docs here.
Concept ACK, but we need more docs here.
I can’t tell (even from looking at the CMake docs) what macOS should be set to and why you’ve chosen this value
I can only assume that the Linux value means “minimum kernel version” for the sake of kernel headers, but I don’t see that in the docs either
Agree with @fanquake that it’s not clear how this affects our other version vars. Which take precedence?
I agree that the documentation is not comprehensive.
As for CMAKE_SYSTEM_VERSION value for Linux, I rely on the fact that its value is picked from uname output for native builds:
0$ cat CMakeLists.txt
1cmake_minimum_required(VERSION 3.22)
2project(test LANGUAGES NONE)
3message("${CMAKE_SYSTEM_VERSION}")
4$ cmake -B build
56.8.0-38-generic
6-- Configuring done (0.0s)
7-- Generating done (0.0s)
8...
9$ uname -r
106.8.0-38-generic
However, I assume that the CMAKE_SYSTEM_VERSION is not used by the current CMake implementation for Linux builds.
Here is the previous discussion on this topic: https://github.com/hebasto/bitcoin/pull/3#discussion_r892222352.
In particular, @ryanofsky noted:
I think this doc is overgeneralizing. If you look at https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html you can see this variable only has meaning when cross compiling for windows and android
you can see this variable only has meaning when cross compiling for windows and android
Given, for example, that if you cross-compile for macOS, with this PR, you end up with different linker flags, this clearly has effect outside of Windows and Android.
Here is an opinion of a CMake maintainer from Professional CMake: A Practical Guide 18th Edition:
The
CMAKE_SYSTEM_VERSIONvariable has different meanings depending on whatCMAKE_SYSTEM_NAMEis set to. … ifCMAKE_SYSTEM_NAMEis set to Android, thenCMAKE_SYSTEM_VERSIONwill typically be interpreted as the default Android API version and must be a positive integer. For other system names, it is not unusual to seeCMAKE_SYSTEM_VERSIONset to something arbitrary like 1, or to not be set at all. …CMAKE_SYSTEM_PROCESSORandCMAKE_SYSTEM_VERSIONare not particularly meaningful for Apple platforms and usually remain unset.
ACK 5ff8074361e9698d6e12e817784295a400b99dab
As a reference, this was tested in hebasto/bitcoin/pull/125 (not triggering cross-compiling unnecessarily) and macOS cross build CI (hebasto/bitcoin/pull/94) is running with it since.
ACK 5ff8074361 the changes look ok.
I just wonder, why the change to depends/funcs.mk is not in hebasto/cmake-staging, but is in this PR?
I just wonder, why the change to
depends/funcs.mkis not inhebasto/cmake-staging, but is in this PR?
All changes to depends/funcs.mk from this PR must be ported to hebasto/cmake-staging.
🐙 This pull request conflicts with the target branch and needs rebase.
Concept ACK, but we need more docs here. I can’t tell (even from looking at the CMake docs) what macOS should be set to and why you’ve chosen this value I can only assume that the Linux value means “minimum kernel version” for the sake of kernel headers, but I don’t see that in the docs either Agree with @fanquake that it’s not clear how this affects our other version vars. Which take precedence?
Where did this get followed up on?