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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - libclang crash on lambda capture using deleted copy constructor"
href="https://bugs.llvm.org/show_bug.cgi?id=46131">46131</a>
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<th>Summary</th>
<td>libclang crash on lambda capture using deleted copy constructor
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>10.0
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>libclang
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>f.dennemont@gmail.com
</td>
</tr>
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<th>CC</th>
<td>klimek@google.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>Created <span class=""><a href="attachment.cgi?id=23554" name="attach_23554" title="The file that crashes libclang.">attachment 23554</a> <a href="attachment.cgi?id=23554&action=edit" title="The file that crashes libclang.">[details]</a></span>
The file that crashes libclang.
== Overview
When using libclang to parse the attached C++ file, it crashes. The C++ file
simply contains a lambda definition that captures by copy an object that has a
deleted copy constructor.
== Steps to Reproduce
1. Download the attached file.
2. Use libclang to parse that file. I use a simple code similar to this for the
parsing :
//---
ClangIndex = createIndex(false, false);
unsigned int options =
CXTranslationUnit_DetailedPreprocessingRecord|CXTranslationUnit_KeepGoing;
char const* const flags = ["-w", "-O0", "--std=c++17", "-c",
"--target=i686-pc-win32", "-fexceptions", "-fno-rtti", "-undef",
"-ferror-limit=100000", "-xc++", "-fshort-wchar",
"-Wno-dollar-in-identifier-extension"];
TU = parseTranslationUnit(ClangIndex, BuildOptions.szFileName, flags,
sizeof(flags)/sizeof(*Flags), Ocp.UnsavedFiles, Ocp.UnsavedFileCount, options);
CXCursor startCursor = getTranslationUnitCursor(TU);
visitChildren(startCursor, buildTree, &Datas);
//---
== Actual Results
The application crashed.
== Expected Results
No crash and libclang gives a diagnostic with a message similar to "call to a
deleted copy constructor".
== Build Date & Hardware
2020-05-29 on Windows 7.
== libclang version : 10 (on that commit :
<a href="https://github.com/llvm/llvm-project/commit/92d5c1be9ee93850c0a8903f05f36a23ee835dc2">https://github.com/llvm/llvm-project/commit/92d5c1be9ee93850c0a8903f05f36a23ee835dc2</a>)
== Additional Information
I fixed the bug locally by simply ignoring a null pointer, like this :
in clang/tools/libclang/CIndex.cpp line 3174 :
// Visit init captures
for (auto InitExpr : E->capture_inits()) {
- if (Visit(InitExpr))
+ if (InitExpr && Visit(InitExpr))
return true;
}</pre>
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