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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [OpenMP] Seg-fault caused by this-capturing lambda in #pragma omp parallel"
href="https://bugs.llvm.org/show_bug.cgi?id=39694">39694</a>
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<th>Summary</th>
<td>[OpenMP] Seg-fault caused by this-capturing lambda in #pragma omp parallel
</td>
</tr>
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<th>Product</th>
<td>OpenMP
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Clang Compiler Support
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>erich.keane@intel.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>AS of r345609, OpenMP supports mapping lambdas in target regions. However, if
the lambda captures 'this', and we're no-longer local to the lambda's 'this',
the call on this line:
(<a href="https://github.com/llvm-mirror/clang/commit/36950cc24f63a783faf9a3db208120b496fd8a84#diff-fb23039c21cc555ae2fb3106a2426fb5R1555">https://github.com/llvm-mirror/clang/commit/36950cc24f63a783faf9a3db208120b496fd8a84#diff-fb23039c21cc555ae2fb3106a2426fb5R1555</a>
to CheckCXXThisCapture seg-faults because the Sema "Active This Type" doesn't
exist.
Godbolt link here: <a href="https://godbolt.org/z/W26nsv">https://godbolt.org/z/W26nsv</a>
Min Reproducer is:
template <typename _Op> void algo(_Op __o) {
#pragma omp parallel
(void)__o;
}
struct S {
void Foo() {
algo([this]() {});
}
};
NOTE that the crash only happens when this is a 'free' function. More
insidiously, if the algorithm itself is in a structure
(<a href="https://godbolt.org/z/_aKG6l">https://godbolt.org/z/_aKG6l</a>), 'this' will capture the wrong thing (see line
36 in the AST output).</pre>
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