[libcxx] Force-cache LIBCXX_CXX_ABI_LIBRARY_PATH

[broadwaylamb]

Summary

The LIBCXX_CXX_ABI_LIBRARY_PATH CMake variable is cached once in
libcxx/cmake/Modules/HandleLibCXXABI.cmake in the setup_abi_lib macro,
and then cached again in libcxx/test/CMakeLists.txt. There, if it is
not set to a value, it is by default set to LIBCXX_LIBRARY_DIR.

However, this new value is not actually cached, because the old (empty)
value has been already cached. Use the FORCE CMake flag so that it
is saved to the cache.

This should not break anything, because the code changed here previously
had no effect, when it should have.

[broadwaylamb]

Can anyone review this small modification?

[broadwaylamb]

Remove unrelated change

[broadwaylamb]

@jroelofs would you mind reviewing this one too, please?

[vvereschaka]

LGTM

[mgorny]

This change broke stand-alone builds. They now try to use libc++abi from the wrong directory, instead of system instance:

clang-10: error: no such file or directory: '/home/mgorny/llvm-project/libcxx/build/lib64/libc++abi.a'

[mgorny]

That said, can we revert this from 10.x branch, please?

[broadwaylamb]

In D69169#1851257, @mgorny wrote:

That said, can we revert this from 10.x branch, please?

I'm investigating it right now, thanks for pointing this out.

[broadwaylamb]

Could you please show me how you're building libc++? I'm having trouble reproducing the issue.

[broadwaylamb]

Anyway, reverted from 10.x in 3573526c0286c9461f0459be1a4592b2214594e7.

[mgorny]

In D69169#1851415, @broadwaylamb wrote:

Could you please show me how you're building libc++? I'm having trouble reproducing the issue.

cmake <path-to-libc++-src> -G Ninja -DLIBCXX_LIBDIR_SUFFIX=64 -DLIBCXX_ENABLE_SHARED=ON -DLIBCXX_ENABLE_STATIC=yes -DLIBCXX_CXX_ABI=libcxxabi -DLIBCXX_CXX_ABI_INCLUDE_PATHS=/usr/include/libcxxabi -DLIBCXX_ENABLE_ABI_LINKER_SCRIPT=OFF -DLIBCXX_HAS_MUSL_LIBC=no -DLIBCXX_HAS_GCC_S_LIB=ON -DLIBCXX_INCLUDE_TESTS=yes -DLIBCXX_USE_COMPILER_RT=OFF -DCMAKE_SHARED_LINKER_FLAGS="-lunwind -Wl,-O1 -Wl,--as-needed" -DLLVM_EXTERNAL_LIT=/usr/bin/lit -DLLVM_LIT_ARGS="-vv;-j;32;--param=cxx_under_test=/usr/lib/llvm/10/bin/x86_64-pc-linux-gnu-clang" -DCMAKE_BUILD_TYPE=RelWithDebInfo &&
ninja check-cxx

[hans]

In D69169#1851438, @broadwaylamb wrote:

Anyway, reverted from 10.x in 3573526c0286c9461f0459be1a4592b2214594e7.

Please don't push directly to the release branch without checking with me. Also, commits should go to master first, before being cherry-picked to any release branches.

I've cherry-picked the revert to master in 1a7e688b0b5a986fbbbce62ff1506a5991b0fce0

Please see http://lists.llvm.org/pipermail/llvm-dev/2020-January/138295.html for more info about the branch.

[broadwaylamb]

In D69169#1854224, @hans wrote:

In D69169#1851438, @broadwaylamb wrote:

Anyway, reverted from 10.x in 3573526c0286c9461f0459be1a4592b2214594e7.

Please don't push directly to the release branch without checking with me. Also, commits should go to master first, before being cherry-picked to any release branches.

I've cherry-picked the revert to master in 1a7e688b0b5a986fbbbce62ff1506a5991b0fce0

Please see http://lists.llvm.org/pipermail/llvm-dev/2020-January/138295.html for more info about the branch.

Understood. Sorry.

[broadwaylamb]

@mgorny I still can't reproduce the issue. What Linux distro are you using and how did you install your LLVM toolchain?

[mgorny]

Gentoo, using the ebuilds. I think the most relevant is how libc++abi is configured:

cmake -G Ninja -DCMAKE_INSTALL_PREFIX=/usr -DLIBCXXABI_LIBDIR_SUFFIX=64 -DLIBCXXABI_ENABLE_SHARED=ON -DLIBCXXABI_ENABLE_STATIC=yes -DLIBCXXABI_USE_LLVM_UNWINDER=yes -DLIBCXXABI_INCLUDE_TESTS=no -DLIBCXXABI_USE_COMPILER_RT=OFF -DLIBCXXABI_LIBCXX_INCLUDES=<path-to-tree>/libcxx/include -DLIBCXXABI_LIBUNWIND_INCLUDES=/usr/include -DCMAKE_BUILD_TYPE=RelWithDebInfo <path>

After normal ninja install, we additionally copy headers (contents of include directory) to /usr/include/libcxxabi, i.e.:

$ tree /usr/include/libcxxabi/
/usr/include/libcxxabi/
├── __cxxabi_config.h
└── cxxabi.h

0 directories, 2 files

[broadwaylamb]

@mgorny Thank you. I've been able to reproduce it on my Ubuntu installation.

libcxx/test/CMakeLists.txt

 pythonize_bool(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY)
 pythonize_bool(LIBCXX_DEBUG_BUILD)
 pythonize_bool(LIBCXX_ENABLE_PARALLEL_ALGORITHMS)
 
 # By default, for non-standalone builds, libcxx and libcxxabi share a library
 # directory.
 if (NOT LIBCXX_CXX_ABI_LIBRARY_PATH)
   set(LIBCXX_CXX_ABI_LIBRARY_PATH "${LIBCXX_LIBRARY_DIR}" CACHE PATH
-      "The path to libc++abi library.")
+      "The path to libc++abi library." FORCE)
 endif()
 
 set(LIBCXX_TARGET_INFO "libcxx.test.target_info.LocalTI" CACHE STRING
     "TargetInfo to use when setting up test environment.")
 set(LIBCXX_EXECUTOR "None" CACHE STRING
     "Executor to use when running tests.")
 
 set(AUTO_GEN_COMMENT "## Autogenerated by libcxx configuration.\n# Do not edit!")

libcxx/utils/libcxx/test/tracing.py

 #===----------------------------------------------------------------------===##
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
 
 import os
 import inspect
 
 
 def trace_function(function, log_calls, log_results, label=''):
     def wrapper(*args, **kwargs):
         kwarg_strs = ['{}={}'.format(k, v) for (k, v) in kwargs]
         arg_str = ', '.join([str(a) for a in args] + kwarg_strs)
-        call_str = '{}({})'.format(function.func_name, arg_str)
+        call_str = '{}({})'.format(function.__name__, arg_str)
 
         # Perform the call itself, logging before, after, and anything thrown.
         try:
             if log_calls:
                 print('{}: Calling {}'.format(label, call_str))
             res = function(*args, **kwargs)
             if log_results:
                 print('{}: {} -> {}'.format(label, call_str, res))