<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJy9Vk1v2zgQ_TXyZVBDoj5sH3RI6gQoNi2Kfl0DWhxZbChSS1Jys79-h1TjOIa7lw0iyBqaHAzfm0fNaGfEY_0hYasevH2Ueg_ewG6USkA7KgV3dz8-QpbTrFFNx6WGg_Qdmaue_2M03Ek9_gIGV18-VgUI0zygBa4FNKYfpOJekpNpKc72GloulYsBkvwqSbdJ-vSs0t_3_JfddqZHMhEJWaXEjowzo23C_Gc17qV2YWRNgy6MIhSyn2jTCb_gXjqP9r3RHn_5uHjPbV8Vy2YYaP8qpwdb0wPQWmPDYOJW8p1C6LgDqQMHhR7BPw4IlCTn7dh4GB3aezfhfYdcoKWFGTfQddkFTrzz62fvP1xJefPWmchYSIA2HoNtjT1wK0Bgo7g9qkhMX53723LNV1Ugm7-QnQAHdqOe6aIAKVB72UpCH2QnApO6n7iS4gXhcMmQlvVLl_W0D8MxHJorWCdsQzckqwvKvy39sgoyZ-nr0J-pJyw7Y9-fqL-c1B_pvy33TR5oZ9lrSX9R-IvUz1U_8i5mIA72qJFeMxTLywUxPkOZnhCEdI2ZMGD1HffAwcmeSq0F6dw4164dogaunDn1pqqdlNdu4M1DUm4JbOf94EIpZrd076kuj7slFb2Q-Oj1bGPokHS22mxYkDMUed9hTJ1VsXUM1lDx7AnHjOysR9C0HbUOnjT7F1qNCoplVsChk01H3QNdqEAhzkQyAPE_LzdVOod-JilESISBh2O8cnmatW-EsQ-N628iEAsZ4Th0j_N2sS9ppBD8KULoT_D1xw24cRiM9QGsNvpdmHr_-XuS38LXzozUIQ8Ytj_6UdGcW2dso7RtDB7CmdGfRqQQC1HnYpNv-IKPtG7rrdmam0_fFqNV9X_ootT0ZN5Rmn5i40_VKdma5YuuxrYqV6u2Kto2Xec5X2fIiyZl1XrDClHkC8V3qFxN5yFhTONhPjs0ppOx-P8IZM1SlmWMfpssZ9ky46LKWclLztsNL9OkSJFUUcsQZ2nsfmHrGHI37h0tKnqX3fMid07uSaYImBB66RXW33Vs1scvlphvc_5tsojY6gjsX_cS3is>52823</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Unable to build LLDB on Amazon Linux 2
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    I'm trying to build full LLVM 13 toolchain within Amazon Linux 2 ARM64 docker and compilation of LLDB fails with:

```
/home/build/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp:63:28: error: variable has incomplete type 'struct user_sve_header'
    struct user_sve_header sve_header;
                           ^
/home/build/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp:63:12: note: forward declaration of 'user_sve_header'
    struct user_sve_header sve_header;
           ^
/home/build/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp:376:13: error: use of undeclared identifier 'sve_vl_valid'
        if (sve_vl_valid(vg_value * 8)) {
            ^
/home/build/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp:562:10: error: use of undeclared identifier 'sve_vl_valid'
    if (!sve_vl_valid(m_sve_header.vl)) {
         ^
/home/build/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_arm64.cpp:930:11: error: use of undeclared identifier 'sve_vl_valid'
      if (sve_vl_valid(m_sve_header.vl))
          ^
4 errors generated.
```

I've discovered that a similar issue has been also discovered in [spack](https://github.com/spack/spack/issues/27992) and the underlying problem is that Amazon Linux 2 is running on Kernel 4.14 which does not provide `user_sve_header` that has been added to kernel 4.15.

The main question is why does LLDB need a kernel with SVE support on non-SVE CPU? Should we add support for building the LLDB without SVE support?
</pre>
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