<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - dereferencing __attribute__((noderef)) should not warn inside sizeof() expressions"
   href="https://bugs.llvm.org/show_bug.cgi?id=48236">48236</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>dereferencing __attribute__((noderef)) should not warn inside sizeof() expressions
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

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

        <tr>
          <th>OS</th>
          <td>Linux
          </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>-New Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>jannh@google.com
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>jannh@google.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>The purpose of __attribute__((noderef)) is to warn about code that will cause
memory to be dereferenced. Currently, clang also warns about code such as:

```
void copy_from_user(void *dst, void __attribute__((noderef)) *src, unsigned
long len);

struct foo {
  int a;
  int b;
};

int test_false_positive_deref(struct foo __attribute__((noderef)) *user_foo) {
  struct foo local_foo;
  copy_from_user(&local_foo, user_foo, sizeof(*user_foo));
  return local_foo.a + local_foo.b;
}
```

noderef checks should be suppressed if isUnevaluatedContext().</pre>
        </div>
      </p>


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