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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Regression in handling 0-length address range entries"
href="https://bugs.llvm.org/show_bug.cgi?id=46805">46805</a>
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<th>Summary</th>
<td>Regression in handling 0-length address range entries
</td>
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<th>Product</th>
<td>tools
</td>
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<th>Version</th>
<td>trunk
</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>
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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>llvm-dwarfdump
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>jh7370.2008@my.bristol.ac.uk
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>This regression was introduced in
<a href="https://reviews.llvm.org/rGed9851a0a682d1ff288ed749287fbc7682ed1514">https://reviews.llvm.org/rGed9851a0a682d1ff288ed749287fbc7682ed1514</a> (see
<a href="https://reviews.llvm.org/D71932">https://reviews.llvm.org/D71932</a> for the review).
A .debug_aranges table might contain an entry for a zero-length function or
data. This is not forbidden by the standard, and can happen in practice. In
such a case, it should not be an error. In up to at least LLVM version 9, this
worked fine, but the cited change caused an error to start occurring. Example:
PS C:\Work\TempWork> llvm-dwarfdump.exe --debug-aranges bar.elf
bar.elf: file format elf64-x86-64
.debug_aranges contents:
error: address range table at offset 0x0 has an invalid tuple (length = 0) at
offset 0x10
A trivial asm input might look like:
foo:
.secton .debug_aranges,"",@progbits
... # Some data for the header
.quad foo
.quad 0 # 0 length
.quad 0 # The .debug_aranges terminator
.quad 0
Note that simply removing the error message is not quite the right fix - we
still want to emit an error if a terminator is detected before the claimed end
of the file, but beware a similar issue to <a class="bz_bug_link
bz_status_NEW "
title="NEW - llvm-dwarfdump cannot handle .debug_ranges/.debug_loc empty relocated range in ET_REL object"
href="show_bug.cgi?id=46804">bug 46804</a>, where in an ET_REL file,
the address might appear to be zero, but it is relocated.</pre>
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