libclang cannot find libclang.dylib

[SteveBronder]

Given the simple program below libclang is not able to find cmath while making the translation unitj

// test.cpp
#include <cmath>

int main() {
  return 1;
}

The script below and a fresh virtual environment gives an error when attempting to parse the translation unit. It cannot find the location of libclang.dylib.

import clang.cindex
filename = "./test.cpp"
comp_args = [
  "-std=c++17",
]  # Add any necessary compiler flags here
translation_unit = clang.cindex.TranslationUnit.from_source(filename, comp_args)

Traceback (most recent call last):
  File "[...]/venv/lib/python3.13/site-packages/clang/cindex.py", line 3949, in get_cindex_library
    library = cdll.LoadLibrary(self.get_filename())
  File "/opt/homebrew/Cellar/[email protected]/3.13.0_1/Frameworks/Python.framework/Versions/3.13/lib/python3.13/ctypes/__init__.py", line 471, in LoadLibrary
    return self._dlltype(name)
           ~~~~~~~~~~~~~^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.13.0_1/Frameworks/Python.framework/Versions/3.13/lib/python3.13/ctypes/__init__.py", line 390, in __init__
    self._handle = _dlopen(self._name, mode)
                   ~~~~~~~^^^^^^^^^^^^^^^^^^
OSError: dlopen(libclang.dylib, 0x0006): tried: 'libclang.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OSlibclang.dylib' (no such file), '/opt/homebrew/lib/libclang.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/lib/libclang.dylib' (no such file), '/opt/homebrew/lib/libclang.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/lib/libclang.dylib' (no such file), '/usr/lib/libclang.dylib' (no such file, not in dyld cache), 'libclang.dylib' (no such file)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<python-input-0>", line 7, in <module>
    translation_unit = clang.cindex.TranslationUnit.from_source(filename, comp_args)
  File "[...]/venv/lib/python3.13/site-packages/clang/cindex.py", line 2991, in from_source
    index = Index.create()
  File "[...]/venv/lib/python3.13/site-packages/clang/cindex.py", line 2877, in create
    return Index(conf.lib.clang_createIndex(excludeDecls, 0))
                 ^^^^^^^^
  File "[...]/venv/lib/python3.13/site-packages/clang/cindex.py", line 224, in __get__
    value = self.wrapped(instance)
  File "[...]/venv/lib/python3.13/site-packages/clang/cindex.py", line 3922, in lib
    lib = self.get_cindex_library()
  File "[...]/venv/lib/python3.13/site-packages/clang/cindex.py", line 3956, in get_cindex_library
    raise LibclangError(msg)
clang.cindex.LibclangError: dlopen(libclang.dylib, 0x0006): tried: 'libclang.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OSlibclang.dylib' (no such file), '/opt/homebrew/lib/libclang.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/lib/libclang.dylib' (no such file), '/opt/homebrew/lib/libclang.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/lib/libclang.dylib' (no such file), '/usr/lib/libclang.dylib' (no such file, not in dyld cache), 'libclang.dylib' (no such file). To provide a path to libclang use Config.set_library_path() or Config.set_library_file().

Manually adding in the location of libclang.dylib allows the translation unit to compile, but gives diagnostic warnings that cmath could not be found

import clang.cindex
clang.cindex.Config.set_library_path("/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/")
filename = "./test.cpp"
comp_args = [
  "-std=c++17",
]  # Add any necessary compiler flags here
print("args: ", comp_args)
translation_unit = clang.cindex.TranslationUnit.from_source(filename, comp_args)
for diag in translation_unit.diagnostics:
    print("Diagnostic:\n")
    print(diag)

./test.cpp:1:10: fatal error: 'cmath' file not found

Then attempting to manually add the resource directory still does not allow libclang to find the correct cmath

clang++ -print-resource-dir
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16

import clang.cindex
clang.cindex.Config.set_library_path("/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/")
filename = "./test.cpp"
comp_args = [
  "-std=c++17",
  "-resource-dir",  "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16"
]  # Add any necessary compiler flags here
print("args: ", comp_args)
translation_unit = clang.cindex.TranslationUnit.from_source(filename, comp_args)
for diag in translation_unit.diagnostics:
    print("Diagnostic:\n")
    print(diag)

args:  ['-std=c++17', '-resource-dir', '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16']
Diagnostic:

./test.cpp:1:10: fatal error: 'cmath' file not found

System information

Software:

    System Software Overview:

      System Version: macOS 14.7 (23H124)
      Kernel Version: Darwin 23.6.0
      Boot Volume: Macintosh HD

Hardware:

    Hardware Overview:

      Model Name: MacBook Pro
      Model Identifier: Mac14,5
      Chip: Apple M2 Max
      System Firmware Version: 11881.1.1

xcode-select -v
xcode-select version 2408.

clang++ --version
Apple clang version 16.0.0 (clang-1600.0.26.3)
Target: arm64-apple-darwin23.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

pip freeze
clang==17.0.6
libclang==18.1.1