MaskRay added a comment. No worries! Thanks for the reply.
I use Debian and want it to work well and support the `-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=on` direction. Currently, `-DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-linux-gnu` (Debian style multiarch triple, so no `-unknown` or `-pc`) does not work for libc++ and some runtime libraries. This led to the revert of D107799 <https://reviews.llvm.org/D107799> which I think really unfortunate because runtime builds encourage `LLVM_ENABLE_PER_TARGET_RUNTIME_DIR`, which de facto deviate from the regular builds and llvm-project has to support two hierarchies. --- Here is `-DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-unknown-linux-gnu`: cmake -GNinja -Hllvm -B/tmp/out/custom1 -DCMAKE_BUILD_TYPE=Release -DCMAKE_CROSSCOMPILING=on -DCMAKE_INSTALL_PREFIX=/tmp/opt/aarch64 -DLLVM_TARGETS_TO_BUILD=AArch64 -DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-unknown-linux-gnu -DLLVM_TARGET_ARCH=AArch64 -DLLVM_ENABLE_PROJECTS='clang;lld' -DLLVM_ENABLE_RUNTIMES='compiler-rt;l ibcxx;libcxxabi;libunwind' ninja -C /tmp/out/custom1 lld cxx cxxabi unwind builtins /tmp/out/custom1/bin/clang++ -c -stdlib=libc++ a.cc; /tmp/out/custom1/bin/clang++ -fuse-ld=lld --dyld-prefix=/usr/aarch64-linux-gnu --unwindlib=libunwind --rtlib=compiler-rt -nostdlib++ -pthread -static-libgcc a.o -Wl,--push-state,-Bstatic,-lc++,-lc++abi,--pop-state,-rpath=/usr/aarch64-linux-gnu/lib -ldl -o a # works ./a # runs if you have binfmt_misc and qemu-aarch64-static If I change the CMake line to use `-DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-linux-gnu`, libc++ compiles do not work: % /tmp/out/custom1/bin/clang++ -fuse-ld=lld --dyld-prefix=/usr/aarch64-linux-gnu -Wl,-rpath=/usr/aarch64-linux-gnu/lib a.cc -o a % ./a # works % /tmp/out/custom1/bin/clang++ -c -stdlib=libc++ a.cc In file included from a.cc:1: In file included from /tmp/out/custom1/bin/../include/c++/v1/stdio.h:101: /tmp/out/custom1/bin/../include/c++/v1/__config:13:10: fatal error: '__config_site' file not found #include <__config_site> ^~~~~~~~~~~~~~~ 1 error generated. `/tmp/out/custom1/include/aarch64-linux-gnu/c++/v1/` is not in the search path. With this change, the command will succeed. Here are the search paths for includes and libraries: % /tmp/out/custom1/bin/clang++ -fuse-ld=lld -stdlib=libc++ -v a.cc |& sed -E 's/ "?-[iIL]/\n&/g' clang version 14.0.0 Target: aarch64-unknown-linux-gnu Thread model: posix InstalledDir: /tmp/out/custom1/bin Found candidate GCC installation: /usr/lib/gcc-cross/aarch64-linux-gnu/11 Selected GCC installation: /usr/lib/gcc-cross/aarch64-linux-gnu/11 Candidate multilib: .;@m64 Selected multilib: .;@m64 "/tmp/out/custom1/bin/clang-14" -cc1 -triple aarch64-unknown-linux-gnu -emit-obj -mrelax-all --mrelax-relocations -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name a.cc -mrelocation-model static -mframe-pointer=non-leaf -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu generic -target-feature +neon -target-feature +v8a -target-abi aapcs -fallow-half-arguments-and-returns -mllvm -treat-scalable-fixed-error-as-warning -debugger-tuning=gdb -v -fcoverage-compilation-dir=/tmp/c -resource-dir /tmp/out/custom1/lib/clang/14.0.0 -internal-isystem /tmp/out/custom1/bin/../include/aarch64-linux-gnu/c++/v1 -internal-isystem /tmp/out/custom1/bin/../include/c++/v1 -internal-isystem /tmp/out/custom1/lib/clang/14.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir=/tmp/c -ferror-limit 19 -fno-signed-char -fgnuc-version=4.2.1 -fcxx-exceptions -fexceptions -target-feature +outline-atomics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/a-ffa089.o -x c++ a.cc clang -cc1 version 14.0.0 based upon LLVM 14.0.0git default target aarch64-linux-gnu ignoring nonexistent directory "/include" #include "..." search starts here: #include <...> search starts here: /tmp/out/custom1/bin/../include/aarch64-linux-gnu/c++/v1 /tmp/out/custom1/bin/../include/c++/v1 /tmp/out/custom1/lib/clang/14.0.0/include /usr/local/include /usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/include /usr/include End of search list. "/tmp/out/custom1/bin/ld.lld" -EL --eh-frame-hdr -m aarch64linux -dynamic-linker /lib/ld-linux-aarch64.so.1 -o a.out /usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/lib/crt1.o /usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/lib/crti.o /usr/lib/gcc-cross/aarch64-linux-gnu/11/crtbegin.o -L/tmp/out/custom1/bin/../lib/aarch64-linux-gnu -L/usr/lib/gcc-cross/aarch64-linux-gnu/11 -L/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../lib64 -L/lib/aarch64-linux-gnu -L/lib/../lib64 -L/usr/lib/aarch64-linux-gnu -L/usr/lib/../lib64 -L/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/lib -L/tmp/out/custom1/bin/../lib -L/lib -L/usr/lib /tmp/a-ffa089.o -lc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc-cross/aarch64-linux-gnu/11/crtend.o /usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/lib/crtn.o > In my testing, I found that these users aren't currently using a single > uniform target triple spelling, I've seen both ${arch}-linux-gnu and > ${arch}-unknown-linux-gnu used pretty liberally. So if we were to land this > change today, it would break many of these users. We could clean up and unify > all of these uses, but it's going to take some effort because it spans lots > of projects. I'm also worried that there might be other Clang users in a > similar situation who are not included on this change. This is not a problem. Both `-DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-linux-gnu` and `-DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-unknown-linux-gnu` will work. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D110663/new/ https://reviews.llvm.org/D110663 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
