Bug 260005
| Summary: | devel/wasi-libcxx: not built to spec and not really useable | ||||||
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| Product: | Ports & Packages | Reporter: | Christoph Moench-Tegeder <cmt> | ||||
| Component: | Individual Port(s) | Assignee: | Christoph Moench-Tegeder <cmt> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Only Me | CC: | fernape, val | ||||
| Priority: | --- | Keywords: | patch | ||||
| Version: | Latest | Flags: | val:
maintainer-feedback+
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| Hardware: | Any | ||||||
| OS: | Any | ||||||
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^Triage: Reporter is committer, assign accordingly. Q/A: Makefile: [34]: use a tab (not space) after a variable name Makefile: [35]: use a tab (not space) after a variable name Makefile: CFLAGS/CXXFLAGS are not needed in CONFIGURE_ENV as they are already added there in bsd.port.mk. Thanks! Patch looks fine. I guess I haven't caught the chicken-and-egg situation because I haven't really used a version built in a clean environment, sorry. > pkg-static: DEVELOPER_MODE: Error: arch "FreeBSD:13:*" -- package installs architecture specific files Well, pkg has no idea about what wasm is, but it likes to detect ELFs and ar archives and blindly assume they "have to" be specific to the *CPU* architecture rather than something portable like wasm. Reported to pkg: https://github.com/freebsd/pkg/issues/2008 BTW initially it actually complained about *malformed* libraries even: https://github.com/freebsd/pkg/issues/1892 (In reply to Fernando Apesteguía from comment #1) > Makefile: CFLAGS/CXXFLAGS are not needed in CONFIGURE_ENV as they are already added there in bsd.port.mk. I beg to differ: poudriere logs (before patch) --CONFIGURE_ENV-- XDG_DATA_HOME=/wrkdirs/usr/ports/devel/wasi-libcxx/work XDG_CONFIG_HOME=/wrkdirs/usr/ports/devel/wasi-libcxx/work XDG_CACHE_HOME=/wrkdirs/usr/ports/devel/wasi-libcxx/work/.cache HOME=/wrkdirs/usr/ports/devel/wasi-libcxx/work TMPDIR="/tmp" PATH=/wrkdirs/usr/ports/devel/wasi-libcxx/work/.bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin:/root/bin SHELL=/bin/sh CONFIG_SHELL=/bin/sh and that, per my analysis, is causing some of the problems here (I could be wrong, but then we'd need to find out what else is happening). (In reply to Christoph Moench-Tegeder from comment #3) You are right. Those variables are added to CONFIGURE_ENV only if HAS_CONFIGURE is set. Sorry for the noise. A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/ports/commit/?id=bf143897d312fc861061eeca33d4cf3e777b6728 commit bf143897d312fc861061eeca33d4cf3e777b6728 Author: Christoph Moench-Tegeder <cmt@FreeBSD.org> AuthorDate: 2021-11-24 20:58:57 +0000 Commit: Christoph Moench-Tegeder <cmt@FreeBSD.org> CommitDate: 2021-11-24 20:58:57 +0000 devel/wasi-libcxx: actually disable exceptions This port was accidentially using the base system compiler for some parts of the configure stages - which gives wrong results in the compiler feature tests, as base clang on FreeBSD 13.0 (llvm 11) does not know about the wasm32 target. Worse, even with the correct compiler some of the feature tests depend on a present and usable libc++ for the wasi target, which we don't have yet (this port will build one, but before...). The end result was that the build system failed to figure out the compiler flags for disabling exceptions (-fno-exceptions in clang's case) and built the wasm libc++ with exceptions enabled. But exceptions are not (yet) supported in wasi-sdk, so trying to build any code against this wasm libc++ failed with linker errors like wasm-ld: error: /usr/local/share/wasi-sysroot/lib/wasm32-wasi/libc++.a(string.cpp.o): undefined symbol: __cxa_allocate_exception wasm-ld: error: /usr/local/share/wasi-sysroot/lib/wasm32-wasi/libc++.a(string.cpp.o): undefined symbol: __cxa_throw To solve that, we have to force the configure stages to use the correct compiler by pushing CC/CXX and related variables into CONFIGURE_ENV and specify the results of the compiler feature tests via cmake arguments. That is a horrible workaround, but short of a full bootstrap build, I can't see any other solution to the chicken-and-egg problem with wasi-libcxx requiring a functional wasi-libc++ to build. PR: 260005 Approved by: greg at unrelenting dot technology (maintainer) devel/wasi-libcxx/Makefile | 75 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 74 insertions(+), 1 deletion(-) committed, thanks. I will need wasi-libc and wasi-libcxx version 13 for firefox 95, but 2021Q4 has only version 11. Do you know if that's safe to cherry-pick over? (In reply to Christoph Moench-Tegeder from comment #7) Why wouldn't it be? So far these ports do not have any dependents, etc. A commit in branch 2021Q4 references this bug: URL: https://cgit.FreeBSD.org/ports/commit/?id=44c66a772c9895ec8d988c07e1dec1c28bae9130 commit 44c66a772c9895ec8d988c07e1dec1c28bae9130 Author: Christoph Moench-Tegeder <cmt@FreeBSD.org> AuthorDate: 2021-11-24 20:58:57 +0000 Commit: Christoph Moench-Tegeder <cmt@FreeBSD.org> CommitDate: 2021-11-29 20:32:31 +0000 devel/wasi-libcxx: actually disable exceptions This port was accidentially using the base system compiler for some parts of the configure stages - which gives wrong results in the compiler feature tests, as base clang on FreeBSD 13.0 (llvm 11) does not know about the wasm32 target. Worse, even with the correct compiler some of the feature tests depend on a present and usable libc++ for the wasi target, which we don't have yet (this port will build one, but before...). The end result was that the build system failed to figure out the compiler flags for disabling exceptions (-fno-exceptions in clang's case) and built the wasm libc++ with exceptions enabled. But exceptions are not (yet) supported in wasi-sdk, so trying to build any code against this wasm libc++ failed with linker errors like wasm-ld: error: /usr/local/share/wasi-sysroot/lib/wasm32-wasi/libc++.a(string.cpp.o): undefined symbol: __cxa_allocate_exception wasm-ld: error: /usr/local/share/wasi-sysroot/lib/wasm32-wasi/libc++.a(string.cpp.o): undefined symbol: __cxa_throw To solve that, we have to force the configure stages to use the correct compiler by pushing CC/CXX and related variables into CONFIGURE_ENV and specify the results of the compiler feature tests via cmake arguments. That is a horrible workaround, but short of a full bootstrap build, I can't see any other solution to the chicken-and-egg problem with wasi-libcxx requiring a functional wasi-libc++ to build. PR: 260005 Approved by: greg at unrelenting dot technology (maintainer) (cherry picked from commit bf143897d312fc861061eeca33d4cf3e777b6728) devel/wasi-libcxx/Makefile | 75 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 74 insertions(+), 1 deletion(-) (In reply to Greg V from comment #8) The question is always "what did I miss?". Thanks, picked&pushed. |
Created attachment 229684 [details] disable exceptions and fix more feature flags in wasi-libcxx platform is FreeBSD 13.0-RELEASE-p5, amd64, poudriere. Trying to use wasi-libcxx (e.g. when building firefox beta with web assembly sandbox) does not work: wasm-ld: error: /usr/local/share/wasi-sysroot/lib/wasm32-wasi/libc++.a(string.cpp.o): undefined symbol: __cxa_allocate_exception wasm-ld: error: /usr/local/share/wasi-sysroot/lib/wasm32-wasi/libc++.a(string.cpp.o): undefined symbol: __cxa_throw wasi-sdk doesn't support exception, so more diagnosis: wasi-libcxx was built with exceptions, there is no "-fno-exceptions" in the build log, even as the port's Makefile specifies "-DLIBCXX_ENABLE_EXCEPTIONS:BOOL=OFF -DLIBCXXABI_ENABLE_EXCEPTIONS:BOOL=OFF". Digging further, I find that wasi-libcxx's CMakeFiles report -- Performing Test LIBCXX_SUPPORTS_FNO_EXCEPTIONS_FLAG -- Performing Test LIBCXX_SUPPORTS_FNO_EXCEPTIONS_FLAG - Failed among others like that (e.g. "LIBCXX_SUPPORTS_WALL_FLAG - Failed"). More digging ensues. => First: CMakeFiles/CMakeErrors.log for libcxxabi reports Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed. Compiler: /usr/bin/c++ That's the wrong compiler - base clang (11.0 in 13) does not know about "--target=wasm32-wasi". The reason is that this cmake was run in post-configure under CONFIGURE_ENV, which does not contain CC/CXX/etc., that's only in MAKE_ENV by default (see any poudrier log, all the environments are listed right at the top). Anyways, that results in many of the compilier feature Tests failing, as the compiler does not know about the target. => Second: Even when using the correct compiler, many feature Tests still fail: wasm-ld: error: cannot open crt1.o: No such file or directory wasm-ld: error: unable to find library -lc++ wasm-ld: error: unable to find library -lc++abi wasm-ld: error: unable to find library -lc Well duh, we're getting into chicken-and-egg territory here. The very ugly workaround is to just pass the Test results as flags to cmake, which will then do the right thing (for at least some cases). Attached patch will: - bump PORTREVISION - put CC/CFLAGS/CXX/CXXFLAGS into CONFIGURE_ENV - pass the Test results into cmake (I'm being generous with the flags here, and I hope I got it all correct - but then "it works for me"). Another nitpick: poudriere complains about pkg-static: DEVELOPER_MODE: Error: arch "FreeBSD:13:*" -- package installs architecture specific files but I'm not touching that right now, between this and firefox beta (it builds!) I've enough for today.