LLDB won't build with standalone (non-Xcode) command-line tools installed

[llvmbot]

Bugzilla Link	46190
Version	trunk
OS	MacOS X
Blocks	#51489
Reporter	LLVM Bugzilla Contributor
CC	@tstellar

[llvmbot]

Environment: macOS 10.15.5

Description: As of June 3-2020, building branch release/10.x or master files fails for project specification:
-DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi;lldb"
when having independent command-line tools installed, i.e. the tools installed in /Library/Developer/CommandLineTools.
This happens irrespective of whether Xcode command-line tools are also installed (/Applications/Xcode.app/Contents/Developer) or not, and also irrespective of path set by $ xcode-select -s

Cause: Having independent command-line tools installed adds
-I/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include
(or equivalent) to compilation paths.
This causes math.h to be included from this directory instead of directory
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1.
File cmath in the .../c++/v1 directory expects math.h from the same directory to be included, but since -I takes precedence of system paths, the wrong math.h is fetched.
This causes compilation of cmath to fail with errors:
c++/v1/cmath:line:col: error: no member named signbit in the global namespace; did you mean sigwait?
Other symbols are also missing: fpclassify, isfinite, isinf, isnan, isnormal, isgreater, ...

Temporary fix: When building LLVM with project lldb, only use Xcode command-line tools and make sure to remove independent command-line tools installations under /Library/Developer/CommandLineTools

[tstellar]

I also hit this bug trying to build lldb from the release/11.x on the Mac OS systems hosted in GitHub actions. Here is a failed build example:

https://github.com/tstellar/llvm-project/pull/208/checks?check_run_id=1299928678

[tstellar]

I also hit this bug trying to build lldb from the release/11.x on the Mac OS
systems hosted in GitHub actions. Here is a failed build example:

tstellar#208
checks?check_run_id=1299928678

Better link to the build logs: https://github.com/tstellar/llvm-project/runs/1299928678?check_suite_focus=true

This is the cmake invocation that fails:

cmake -DLLVM_INCLUDE_GO_TESTS=OFF -DLLVM_LIT_ARGS=-svj1 ../llvm -G Ninja -DLLVM_ENABLE_PROJECTS="clang;lldb" -DCMAKE_BUILD_TYPE=Release -DLLDB_INCLUDE_TESTS=OFF

[tstellar]

mentioned in issue #51489

[tstellar]

The deadline for requesting fixes for the release has passed. This bug is being removed from the LLVM 13.0.1 release milestone. If you have a fix or think this bug is important enough to block the release, please explain why in a comment and add the bug back to the LLVM 13.0.1 release milestone.

[tstellar]

I will need to see your full cmake log to know if you are having the same issue, but I've found the root cause for this failure in the GitHub Actions runner: actions/runner-images#5900

[llvmbot]

@llvm/issue-subscribers-lldb

| | | | --- | --- | | Bugzilla Link | [46190](https://llvm.org/bz46190) | | Version | trunk | | OS | MacOS X | | Blocks | llvm/llvm-project#51489 | | Reporter | LLVM Bugzilla Contributor | | CC | @tstellar |