<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/123848>123848</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [compiler-rt] circular dependency on libc
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            compiler-rt
      </td>
    </tr>

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

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

<pre>
    cc @petrhosek @frobtech @michaelrj-google @pcc @compnerd 

Ideally, we'd be able to build the compiler builtins without depending on the libc (for purposes of bootstrapping a system).  Right now, I observe build failures for the `builtins` ninja target when attempting to bootstrap such a sysroot:

- compiler-rt/lib/builtins/emutls.c depends on <stdlib.h>
- compiler-rt/lib/builtins/clear_cache.c depends on <assert.h>
- compiler-rt/lib/builtins/enable_execute_stack.c depends on <sys/mman.h>
- compiler-rt/lib/builtins/eprintf.c depends on <stdio.h>
- compiler-rt/lib/builtins/cpu_model/x86.c depends on <assert.h>

It looks like `COMPILER_RT_BAREMETAL_BUILD` can be unset to disable the addition of emutls.c, enable_execute_stack.c, and eprintf.c . (Ah @petrhosek has been here before, thanks @petrhosek !)  AFAICT, there's currently no cmake option to skip building the rest.

Otherwise, it seems like we may have a circular dependency between the compiler builtins and the libc.
</pre>
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