On Mon, Oct 25, 2021 at 1:28 PM Louis Dionne <ldio...@apple.com> wrote:
> I believe the issue is probably not related so much to > LLVM_ENABLE_PROJECTS vs LLVM_ENABLE_RUNTIMES, but rather to the fact that > LLVM_ENABLE_RUNTIMES uses per-target runtime directories now (hasn't always > been the case), which basically means that libc++ ends up in > `<prefix>/lib/<target-triple>/libc++.so` instead of > `<prefix>/lib/libc++.so`. > Ish, yes. It's a bug in LLVM_ENABLE_RUNTIMES that isn't present in LLVM_ENABLE_PROJECTS, so for now if I want to run the lldb pretty printer tests for libc++ on Linux it seems the only way I can is by using the deprecated functionality of libc++ in LLVM_ENABLE_PROJECTS. Consider this a bug report (looks like a bug in the lldb CMake configuration, not in libc++'s build itself, but something to figure out if Linux lldb devs are going to use libc++ +.ENABLE_RUNTIMES path) on that deprecation? > I think you either want to specify the per-target library dir when running > against libc++, or you want to disable that and use > `LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF` when configuring the runtimes. In > all cases, you want to be using `LLVM_ENABLE_RUNTIMES` and not > `LLVM_ENABLE_PROJECTS`, since the latter is deprecated now. > I didn't enable LLVM_ENABLE_PER_TARGET_RUNTIME_DIR myself/in the root cmake config. It looks like it's hardcoded(?) into the ENABLE_RUNTIMES sub-build? https://github.com/llvm/llvm-project/blob/e5fb79b31424267704e9d2d9674089fd7316453e/llvm/runtimes/CMakeLists.txt#L76 I'm not sure there's any way to override that from the root? And in any case I'd have thought the defaults would need to/be intended to work correctly on supported platforms? So something in lldb's dir handling (maybe some general infrastructure in LLVM could use some improvement to provide an LLVM_RUNTIME_LIBS_DIR, or similar? that could then be used from other places - rather than libc++, for instance, creating that directory for itself based on LLVM_LIBS_DIR and LLVM_ENABLE_PER_TARGET_RUNTIME_DIR, etc) needs some fixes to support the current defaults/hardcoded modes on Linux? > Cheers, > Louis > > On Oct 25, 2021, at 13:57, David Blaikie <dblai...@gmail.com> wrote: > > +Louis Dionne <ldio...@apple.com> - perhaps the libcxx and lldb folks > would be interesting in finding a suitable way to address this issue, since > currently either option (using libcxx in ENABLE_PROJECTS or using it in > ENABLE_RUNTIMES) is incomplete - if I use ENABLE_RUNTIMES I get the libcxx > testing run against the just-built clang and generally this is the > "supported" configuration, but then some lldb tests fail because they can't > find libcxx.so.1 (on Linux) - and using ENABLE_PROJECTS means not using the > just-built clang for libcxx tests (so missing the libcxx breakages caused > by my array name change) but do use the just-built libcxx in lldb tests and > find failures there... > > On Wed, Oct 20, 2021 at 1:57 PM David Blaikie <dblai...@gmail.com> wrote: > >> On Tue, Oct 19, 2021 at 4:55 PM David Blaikie <dblai...@gmail.com> wrote: >> >>> On Tue, Oct 19, 2021 at 9:08 AM Raphael Isemann <teempe...@gmail.com> >>> wrote: >>> >>>> Actually the RPATH theory is wrong, but the LLVM_ENABLE_PROJECT >>>> workaround *should* still work. >>>> >>> >>> I'll give that a go (it's running at the moment) though I guess this is >>> inconsistent with the direction libcxx is moving in for building, re: >>> https://groups.google.com/g/llvm-dev/c/tpuLxk_ipLw >>> >> >> Yep, it does work with LLVM_ENABLE_PROJECT rather than >> LLVM_ENABLE_RUNTIME. >> >> Specifically the test binary is linked with an rpath to the just-built >> lib directory that ensures the just-built libc++.so is found: >> >> /usr/local/google/home/blaikie/dev/llvm/build/release/bin/clang main.o -g >> -O0 -fno-builtin -m64 >> -I/usr/local/google/home/blaikie/dev/llvm/src/lldb/packages/Python/lldbsuite/test/make/../../../../../include >> -I/usr/local/google/home/blaikie/dev/llvm/src/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/list >> -I/usr/local/google/home/blaikie/dev/llvm/src/lldb/packages/Python/lldbsuite/test/make >> -include >> /usr/local/google/home/blaikie/dev/llvm/src/lldb/packages/Python/lldbsuite/test/make/test_common.h >> -fno-limit-debug-info -gsplit-dwarf -stdlib=libc++ >> -Wl,-rpath,/usr/local/google/home/blaikie/dev/llvm/build/release/./lib >> --driver-mode=g++ -o "a.out" >> >> Oh, actually it passes the same rpath when using LLVM_ENABLE_RUNTIME, but >> the libc++.so.1 is in a different place: >> ./lib/x86_64-unknown-linux-gnu/libc++.so.1 >> >> Looks like this rpath setting happens here: (changing this to a junk >> argument causes the test to fail to build as expected) >> >> https://github.com/llvm/llvm-project/blob/618583565687f5a494066fc902a977f6057fc93e/lldb/packages/Python/lldbsuite/test/make/Makefile.rules#L400 >> >> And it gets the LLVM_LIBS_DIR from here: >> https://github.com/llvm/llvm-project/blob/207998c242c8c8a270ff22a5136da87338546725/lldb/test/API/lit.cfg.py#L163 >> >> So maybe we need to pass down the default target triple too, since that >> seems to be how libc++ is deciding where to put the library? ( >> https://github.com/llvm/llvm-project/blob/207998c242c8c8a270ff22a5136da87338546725/libcxx/CMakeLists.txt#L424 >> ) at least on non-apple :/ (or maybe there's some way to make the >> connection between the two less brittle - for libc++'s build to export some >> variable that lldb can use, or for LLVM to provide something for both to >> use?) >> >> Yeah, applying this change does work for me, but wouldn't work on Apple >> for instance (where libcxx doesn't add the default target triple to the >> path): >> $ git diff >> *diff --git lldb/test/API/lit.site.cfg.py.in <http://lit.site.cfg.py.in/> >> lldb/test/API/lit.site.cfg.py.in <http://lit.site.cfg.py.in/>* >> *index 987078a53edb..e327429b7ff9 100644* >> *--- lldb/test/API/lit.site.cfg.py.in <http://lit.site.cfg.py.in/>* >> *+++ lldb/test/API/lit.site.cfg.py.in <http://lit.site.cfg.py.in/>* >> @@ -3,7 +3,7 @@ >> config.llvm_src_root = "@LLVM_SOURCE_DIR@" >> config.llvm_obj_root = "@LLVM_BINARY_DIR@" >> config.llvm_tools_dir = "@LLVM_TOOLS_DIR@" >> -config.llvm_libs_dir = "@LLVM_LIBS_DIR@" >> +config.llvm_libs_dir = "@LLVM_LIBS_DIR@/@LLVM_DEFAULT_TARGET_TRIPLE@" >> config.llvm_shlib_dir = "@SHLIBDIR@" >> config.llvm_build_mode = "@LLVM_BUILD_MODE@" >> config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@" >> >> Thoughts? >> > >
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