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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang-cl can't be used with midl"
href="https://bugs.llvm.org/show_bug.cgi?id=40140">40140</a>
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<th>Summary</th>
<td>clang-cl can't be used with midl
</td>
</tr>
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>mh+llvm@glandium.org
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</tr>
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>midl, a tool part of the Windows SDK, defaults to use cl.exe as a preprocessor.
One can override that with the /cpp_cmd flag to midl, and for people trying not
to depend on MSVC at all, it would seem like a good idea to pass clang-cl
there. But that doesn't work.
midl invokes the preprocessor with the following command line:
$preprocessor -E -D__midl=801 path/to/file.idl
with clang-cl, this fails because -E is ignored and the idl file is considered
as a linker input. So it warns about command line arguments being unused, and
gives no preprocessed output.
e.g.:
$ c:/Users/glandium/.mozbuild/clang/bin/clang-cl.exe -E -D__midl=801
c:/Users/glandium/Desktop/mozilla-unified/accessible/ipc/win/typelib/Accessible.idl
clang-cl: warning:
c:/Users/glandium/Desktop/mozilla-unified/accessible/ipc/win/typelib/Accessible.idl:
'linker' input unused [-Wunused-command-line-argument]
clang-cl: warning: argument unused during compilation: '-D __midl=801'
[-Wunused-command-line-argument]</pre>
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