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      <base href="https://llvm.org/bugs/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - Clang-4.0 crashes/assert while evaluating __builtin_object_size: "APValues can't handle invalid LValue bases""
   href="https://llvm.org/bugs/show_bug.cgi?id=31843">31843</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Clang-4.0 crashes/assert while evaluating __builtin_object_size:  "APValues can't handle invalid LValue bases"
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>4.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Frontend
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>mehdi.amini@apple.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Simple reproduction (build as C file):


struct statfs { char f_mntonname[1024];};
fn1() {
  struct statfs *outStatFSBuf;
  __builtin_object_size (outStatFSBuf->f_mntonname ? outStatFSBuf : "", 2 > 1 ?
1 : 0);
}


AFAICT what happens is that in:

  static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {


we're doing:

  } else if (T->hasPointerRepresentation()) {
    LValue LV;
    if (!EvaluatePointer(E, LV, Info))
      return false;
    LV.moveInto(Result);


The issue is that `Info.allowInvalidBaseExpr()` is true, so `EvaluatePointer`
returns true even though the Base is marked as invalid in the result `LV`.
We then assert in the call  `LV.moveInto(Result);`   "APValues can't handle
invalid LValue bases"</pre>
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