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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - x32: segfault with -fpic when initializing vtable ptr"
href="https://bugs.llvm.org/show_bug.cgi?id=38932">38932</a>
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<th>Summary</th>
<td>x32: segfault with -fpic when initializing vtable ptr
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: X86
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>theonetruecamper@gmx.de
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>This may be a duplicate for <a class="bz_bug_link
bz_status_NEW "
title="NEW - PC-relative address isn't used for x32"
href="show_bug.cgi?id=22676">https://bugs.llvm.org/show_bug.cgi?id=22676</a> ?
The following test code immediately segfaults when compiled with -fpic -mx32:
==> test.cpp <==
struct A {
virtual ~A() {}
};
int main() {
A a;
}
looking at the assembler output shows why:
# clang++ test.cpp -fpic -mx32 -S && cat test.s | c++filt | grep "A::A():" -A 8
A::A(): # @A::A()
.cfi_startproc
# %bb.0:
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset %rbp, -16
movl %esp, %ebp
.cfi_def_cfa_register %rbp
movl vtable for A@GOTPCREL, %ea # <== segfault here, (%rip) is
missing
compared to
# clang++ test.cpp -fpic -m64 -S && cat test.s | c++filt | grep "A::A():" -A 8
A::A(): # @A::A()
.cfi_startproc
# %bb.0:
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset %rbp, -16
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
movq vtable for A@GOTPCREL(%rip), %rax</pre>
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