[Chapel Merge] Link chpl with the same libc++ that built the Home

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Branch: refs/heads/main
Revision: 4bd353c
Author: mppf
Link: Link chpl with the same libc++ that built the Homebrew LLVM by mppf · Pull Request #19445 · chapel-lang/chapel · GitHub
Log Message:

Merge pull request #19445 from mppf/address-19217

Link chpl with the same libc++ that built the Homebrew LLVM

Resolves #19217

This PR adds a workaround to solve #19217. The problem we were seeing is
that the Homebrew LLVM is built with one C++ standard library, but it
includes a different version of a C++ standard library that our include
and link paths were picking up. This can be detected with comparing
output of otool -L chpl vs otool -l libLLVM.dylib (with appropriate
paths).

To fix it, this PR adjusts chpl_llvm.py to:

  • compute the sdk used when building the llvm/clang Homebrew package.
    The current strategy is to find the DEFAULT_SYSROOT define from
    clang/Config/config.h. This strategy relies on the Homebrew formula
    passing -DDEFAULT_SYSROOT=#{macos_sdk} when cmake'ing llvm and
    clang. The main alternative strategy that I know of for this is more
    complex and relies on running both otool and xcrun.
  • Put -I and -L paths based on this sdk first in the system compile
    options so that we find the sdk libc++ rather than one from the
    Homebrew package

While there, I fixed some problems in error reporting when checking an
llvm-config.

Reviewed by @ronawho - thanks!

Testing:

  • thanks to @ronawho and @aconsroe-hpe for helping test some of these
    configs

  • [ ] full local testing

  • [x] Ubuntu 21.10 system still works with system LLVM

  • [x] Ubuntu 21.10 system with homebrew works with homebrew llvm@12

  • [x] Monterey (12.2) ARM Mac with llvm@11, llvm@12, and llvm@13

  • [x] Monterey (12.2) x86 Mac with llvm@11, llvm@12, and llvm@13

  • [x] Big Sur (11.6) x86 Mac with llvm@12 and llvm@13

  • [x] Catalina (10.15.7) x86 Mac with llvm@11, llvm@12, and llvm@13

  • [x] some of the above Mac systems have xcode and some only have command
    line tools

    Modified Files:
    M util/chplenv/chpl_llvm.py

    Compare: Comparing 080e5b797287...4bd353ce8261 · chapel-lang/chapel · GitHub