<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - llvm-dwarfdump with DWARF3: error: Unable to resolve DW_LLE_offset_pair: base address unknown"
href="https://bugs.llvm.org/show_bug.cgi?id=44482">44482</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>llvm-dwarfdump with DWARF3: error: Unable to resolve DW_LLE_offset_pair: base address unknown
</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>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>DebugInfo
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>meyer@absint.com
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, keith.walker@arm.com, labath@google.com, llvm-bugs@lists.llvm.org, paul_robinson@playstation.sony.com
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22995" name="attach_22995" title="test case">attachment 22995</a> <a href="attachment.cgi?id=22995&action=edit" title="test case">[details]</a></span>
test case
We have a test case built with CompCert, for which (I think ;-) llvm-dwarfdump
falsely emits an error on "llvm-dwarfdump -all -verify $attached_binary":
<span class="quote">> error: Unable to resolve DW_LLE_offset_pair: base address unknown</span >
This only happened after upgrading llvm to a newer trunk. Tested last week with
git/master cd2a73a9f01b2ec1b7e239ba83201199df0d7912 (the relevant code doesn't
seem to have changed since then).
The problem seems to be that some DWARF3 .debug_loc info is parsed as a DWARF5
DW_LLE_offset_pair, and in that case the parser (now) always expects a
DW_LLE_base_address to be set - else it emits the above error. For DWARF5 that
would be correct, however, for DWARF3 there are no DW_LLE_* codes, and the
parser should just use an offset of 0.
Some digging points to <a href="https://reviews.llvm.org/D70081">https://reviews.llvm.org/D70081</a> and commit
<a href="https://github.com/llvm/llvm-project/commit/ebe2f56030458e7a4c2375c6d92a48f0ed01eb5b">https://github.com/llvm/llvm-project/commit/ebe2f56030458e7a4c2375c6d92a48f0ed01eb5b</a>
- more specifically, the code around the "if (!Base)" at
<a href="https://github.com/llvm/llvm-project/blame/master/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp#L81">https://github.com/llvm/llvm-project/blame/master/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp#L81</a>
Hence adding labath to CC list.
Tool output:
<span class="quote">> Verifying [...]
> Verifying .debug_abbrev...
> Verifying .debug_info Unit Header Chain...
> error: Unable to resolve DW_LLE_offset_pair: base address unknown
>
> 0x00000297: DW_TAG_formal_parameter
> DW_AT_name ("x")
> DW_AT_type (0x0000000000000066 "int")
> DW_AT_location (0x00000000:
> (0x000000000040ad80, 0x000000000040ad84): DW_OP_reg0)
>
> Verifying .debug_info references...
> Verifying .debug_types Unit Header Chain...
> Verifying .debug_line...
> Errors detected.</span >
debug_info (header), only a single CU, version is 3:
<span class="quote">> Compilation Unit @ offset 0x0:
> Length: 0x2a1 (32-bit)
> Version: 3
> Abbrev Offset: 0x0
> Pointer Size: 8</span >
debug_info (for this entry the verification fails):
<span class="quote">> <2><297>: Abbrev Number: 13 (DW_TAG_formal_parameter)
> <298> DW_AT_name : x
> <29a> DW_AT_type : <0x66>
> <29e> DW_AT_location : 0x0 (location list)</span >
debug_abbrev for the above entry:
<span class="quote">> 13 DW_TAG_formal_parameter [no children]
> DW_AT_name DW_FORM_string
> DW_AT_type DW_FORM_ref_addr
> DW_AT_location DW_FORM_data4
> DW_AT value: 0 DW_FORM value: 0</span >
debug_loc:
<span class="quote">> Offset Begin End Expression
> 00000000 000000000040ad80 000000000040ad84 (DW_OP_reg0 (x0))
> 00000013 <End of list</span >
The attached binary is built with (latest as of 30th Dec) CompCert for AArch64.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>