<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/55042>55042</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            ld64.lld should refuse to link against subumbrellas
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            lld:MachO
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          nico
      </td>
    </tr>
</table>

<pre>
    ld64 rejects this:

```
% cat cs.m
void f() {}

% clang -shared cs.m /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/system/libmacho.tbd         
ld: cannot link directly with /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/system/libmacho.tbd.  Link against the umbrella framework 'System.framework' instead. for architecture arm64
```

We don't:

```
 % clang -shared cs.m /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/system/libmacho.tbd -fuse-ld=$PWD/third_party/llvm-build/Release+Asserts/bin/ld64.lld
```

We should.
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzVU0uPmzAQ_jXmYgWBE_I4cEga5dJWu2oOu7fKxgO4MRh5TFb59x2T0JeqPbfIGvmbF9-MZ5TTt9Lq9Yp7-AZVQB5ag2y5Z9mRZbNcZ49zh6LglQy8wrS7a67OaF4zsWVix9nmwDbH3-JjgJV9wxfYSg96CuVMnPbDYA3lMq5Hgq-V05DKYaD7B9cH6ENUH-EK1g3g6f5sZaid76L-s6yezq_p8FD94Xk-fvzFCfWFwIjRYo0iiTcM0N1hJ6vWpUFpPn935lZTK6jYvneBW9NfuDae2mRv_M2E9p8sIeX8U2QqG2l6DPSgwMdOebBW8trLDt6cvxD1zXkKT3_oSMVjCEhKQnS49FVrAtU7eiDQrVd_H4hJvgDXrqcc4f3x4f_TOCzqEWERx-DIxOr5heSJNsTrr4P04Rbd7bVbqNGQjzh9AQsSgYnDHhH8RFeZPrrRjqWWnN5tILZutDpNdLnUu-VOJsEEC-Uc_LDTrkZaPLj7TM4vjaOaHxqT0duyDWGYllmc6DQ0saNKK9c9aM_sB-_i7hM0iCNE0kWRrUTSllUBqsj1pqjWsJYbvS1qEFqts2Wx3KpVkVipwGLJigMTwk77Qi1unwix4piYUmRCUC6RbwQlTcU2yyFXoshzXdUyY6sMOmlsGpmkzjeJLx8tbZCM1mDAn0aJaJoeYPoh5ZdjaJ0ve1O5ZCJfTsy_AxeFiYQ">