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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 - After r318497, --as-needed does not seem to work correctly anymore"
href="https://bugs.llvm.org/show_bug.cgi?id=36029">36029</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>After r318497, --as-needed does not seem to work correctly anymore
</td>
</tr>
<tr>
<th>Product</th>
<td>lld
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>release blocker
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>ELF
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>dimitry@andric.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Using recent versions of lld 6.0.0 in FreeBSD, we've noticed that libgcc_s.so
always gets linked into executables and libraries, even if none of its
functions appear to be used.
E.g.:
$ cat main.c
int main(void) { return 0; }
$ cc -c main.c -o main.o
(The following is what cc normally runs to link a plain executable)
$ ld.lld --eh-frame-hdr -dynamic-linker /libexec/ld-elf.so.1 --hash-style=both
--enable-new-dtags -o main /usr/lib/crt1.o /usr/lib/crti.o /usr/lib/crtbegin.o
-L/usr/lib main.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc
--as-needed -lgcc_s --no-as-needed /usr/lib/crtend.o /usr/lib/crtn.o
$ readelf -d main
Dynamic section at offset 0x3028 contains 19 entries:
Tag Type Name/Value
0x0000000000000001 NEEDED Shared library: [libgcc_s.so.1]
0x0000000000000001 NEEDED Shared library: [libc.so.7]
0x0000000000000015 DEBUG 0x0
[...]
This appears to have regressed with <a href="https://reviews.llvm.org/rL318497">https://reviews.llvm.org/rL318497</a> ("Remove
IsLocal"). Linking with lld just before that avoids pulling in libgcc_s.so:
$ ~/obj/lld-318496/bin/ld.lld --eh-frame-hdr -dynamic-linker
/libexec/ld-elf.so.1 --hash-style=both --enable-new-dtags -o main
/usr/lib/crt1.o /usr/lib/crti.o /usr/lib/crtbegin.o -L/usr/lib main.o -lgcc
--as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed
/usr/lib/crtend.o /usr/lib/crtn.o
$ readelf -d main
Dynamic section at offset 0x3028 contains 18 entries:
Tag Type Name/Value
0x0000000000000001 NEEDED Shared library: [libc.so.7]
0x0000000000000015 DEBUG 0x0
[...]</pre>
</div>
</p>
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