<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/54312>54312</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Missing support for GCC's attribute access (IR attributes with size index?)
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang:codegen
      </td>
    </tr>

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

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

<pre>
    https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes

`access (access-mode, ref-index)
access (access-mode, ref-index, size-index)`

_The access attribute specifies that a function to whose by-reference arguments the attribute applies accesses the referenced object according to access-mode. The access-mode argument is required and must be one of four names: read_only, read_write, write_only, or none. The remaining two are positional arguments._

We have IR attributes read_only and  read_only, so mapping for these two modes could be easy. In terms of _size-index_, maybe we could extend existing IR attributes to optionally take _size-index_?

cc @jdoerfert (IR attributes)
cc @fhahn (DSE)
cc @nikic (Rust side; can this generalization of IR attributes be useful for Rust?)


</pre>
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