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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - __attribute__((used)) possibly ignored for static function with inline assembler?"
href="http://llvm.org/bugs/show_bug.cgi?id=21292">21292</a>
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<th>Summary</th>
<td>__attribute__((used)) possibly ignored for static function with inline assembler?
</td>
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<th>Product</th>
<td>clang
</td>
</tr>
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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>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>LLVM Codegen
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>danalbert@google.com
</td>
</tr>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, srhines@google.com
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<th>Classification</th>
<td>Unclassified
</td>
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<p>
<div>
<pre>I've come across what looks like a bug in the integrated assembler. It looks
like __attribute__((used)) is being ignored.
We're seeing the following link error:
cxa_exception.o(.text.__cxa_end_cleanup+0x2): warning: relocation refers to
discarded section
The relocation at .text.__cxa_end_cleanup+0x2 is to:
<a href="https://github.com/llvm-mirror/libcxxabi/blob/master/src/cxa_exception.cpp#L314">https://github.com/llvm-mirror/libcxxabi/blob/master/src/cxa_exception.cpp#L314</a>
Removing the static keyword allows it to pass, and removing the attribute
results in an undefined reference, so clearly used is having _some_ effect.
Our compilation line (pruned to remove the uninteresting android parts):
clang++ -I external/libcxxabi/include/ -I external/libcxx/include/ -I
external/libcxxabi -c -msoft-float -ffunction-sections -fdata-sections
-funwind-tables -fstack-protector -fno-short-enums -no-canonical-prefixes
-march=armv7-a -mfloat-abi=softfp -mfpu=neon -fmessage-length=0
-fvisibility-inlines-hidden -target arm-linux-androideabi -mthumb -Os
-fomit-frame-pointer -fno-strict-aliasing -frtti -fPIC -std=c++11
-fexceptions -integrated-as external/libcxxabi/src/cxa_exception.cpp
More discussion: <a href="https://android-review.googlesource.com/#/c/110170/">https://android-review.googlesource.com/#/c/110170/</a>
Possibly related:
<a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Failure to emit attribute(used) inline methods defined in nested classes"
href="show_bug.cgi?id=19743">http://llvm.org/bugs/show_bug.cgi?id=19743</a>
<a class="bz_bug_link
bz_status_NEW "
title="NEW --- - __attribute__((used)) ignored in templated classes"
href="show_bug.cgi?id=17480">http://llvm.org/bugs/show_bug.cgi?id=17480</a>
Our clang is based on r212749, so it's possible that this has been fixed
already.</pre>
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