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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Inplace new-ing an array overwrites the square of the memory"
href="https://bugs.llvm.org/show_bug.cgi?id=42096">42096</a>
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<th>Summary</th>
<td>Inplace new-ing an array overwrites the square of the memory
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>8.0
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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>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>alisdairm@me.com
</td>
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>When in-place new-ing a local variable of an array of trivial type, the
generated code calls 'memset' with the square of the size of the array,
corrupting the stack.
Quick example:
#include <new>
template <typename TYPE>
void f()
{
typedef TYPE TArray[7];
TArray x;
new(&x) TArray();
}
int main()
{
f<char>();
f<int>();
}
Sample code generation can be seen for Clang 7 and 8 via godbolt:
<a href="https://godbolt.org/z/WjhFrc">https://godbolt.org/z/WjhFrc</a></pre>
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