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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 - -m option is not ignored when is immediately preceded by -o option"
href="https://bugs.llvm.org/show_bug.cgi?id=52583">52583</a>
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<th>Summary</th>
<td>-m option is not ignored when is immediately preceded by -o option
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>unspecified
</td>
</tr>
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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>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>-New Bugs
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>egor.suvorov@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
</td>
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<p>
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<pre>Here is an issue that one of my students encountered today with GCC, but Clang
is also affected:
<a href="https://stackoverflow.com/questions/70069809/unrecognized-emulation-mode-ain-when-compiling-with-gcc-on-ubuntu/70069810">https://stackoverflow.com/questions/70069809/unrecognized-emulation-mode-ain-when-compiling-with-gcc-on-ubuntu/70069810</a>
Consider any simple C++ program in a file named `main.cpp`. I compile it with
`clang++ main.cpp -o main`, but I accidentally add a dash before `main`:
clang++ main.cpp -o -main
Expected behavior: the program is compiled to a file named `-main`.
Real behavior:
/usr/bin/ld: unrecognised emulation mode: ain
Supported emulations: elf_x86_64 elf32_x86_64 elf_i386 elf_iamcu elf_l1om
elf_k1om i386pep i386pe
clang: error: linker command failed with exit code 1 (use -v to see invocation)
My understanding: Clang treats `-main` as both `-m` option (targeting some
unexisting `ain` architecture) AND name for the output file.
For example, on my 64-bit Ubuntu I can write
clang++ main.cpp -o -melf_x86_64
and it will produce a binary named `-melf_x86_64`. However, the following
command fails because I don't have 32-bit standard library installed:
clang++ main.cpp -o -melf_i386
yields:
/usr/bin/ld: skipping incompatible
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/libstdc++.so when searching for
-lstdc++
/usr/bin/ld: skipping incompatible
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/libstdc++.a when searching for -lstdc++
/usr/bin/ld: cannot find -lstdc++
/usr/bin/ld: skipping incompatible
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../x86_64-linux-gnu/libm.so when
searching for -lm
/usr/bin/ld: skipping incompatible
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../x86_64-linux-gnu/libm.a when
searching for -lm
/usr/bin/ld: skipping incompatible /lib/x86_64-linux-gnu/libm.so when searching
for -lm
/usr/bin/ld: skipping incompatible /lib/x86_64-linux-gnu/libm.a when searching
for -lm
/usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libm.so when
searching for -lm
/usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libm.a when
searching for -lm
/usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libm.so when
searching for -lm
/usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libm.a when
searching for -lm
/usr/bin/ld: cannot find -lm
/usr/bin/ld: skipping incompatible
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../x86_64-linux-gnu/libgcc_s.so.1
when searching for libgcc_s.so.1
/usr/bin/ld: skipping incompatible /lib/x86_64-linux-gnu/libgcc_s.so.1 when
searching for libgcc_s.so.1
/usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libgcc_s.so.1 when
searching for libgcc_s.so.1
/usr/bin/ld: skipping incompatible
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I suspect some other options may be be affected as well. `-m` here is special
only because `main` start with `m`.
Being able to read the option in two different ways simultaneously looks like a
bug in my world.
I can reproduce the behavior on a wide range of OSes: LLVM on Windows 10
(clang++ version 13.0.0 Target: x86_64-w64-windows-gnu by msys2 project),
clang++ 10.0.0-4ubuntu1 on 64-bit Ubuntu 20.04.3 LTS, as well as trunk version
on Godbolt.</pre>
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