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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - ARM FastIsel is renaming the memcpy to memcpy.<random-number> in getLibcallReg()."
href="https://bugs.llvm.org/show_bug.cgi?id=43202">43202</a>
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<th>Summary</th>
<td>ARM FastIsel is renaming the memcpy to memcpy.<random-number> in getLibcallReg().
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<th>Product</th>
<td>clang
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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
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>LLVM Codegen
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>umesh.kalappa0@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22461" name="attach_22461" title="testcase">attachment 22461</a> <a href="attachment.cgi?id=22461&action=edit" title="testcase">[details]</a></span>
testcase
The attached file compiled like
clang --target=arm-linux-eabi -mcpu=cortex-a9 -w -fno-builtin -mlong-calls
testcase.cpp -c; nm testcase.o | grep memcpy
U memcpy
U memcpy.202
U memcpy.203
U memcpy.204
results with linker undefined symbols error .
When we investigated why the codegen renames it ,the following code
ARMFastISel.cpp @ getLibcallReg do so.
<span class="quote">>>GlobalValue *GV = new GlobalVariable(M, Type::getInt32Ty(*Context), false,</span >
GlobalValue::ExternalLinkage, nullptr,
Name);
where "Name=memcpy" in this case and GlobalVariable creates new instance with
"Name" if doesn't exist in the module table ,else its renames with appending
the random number to "Name".
But its not the semantics we required here ,hence we modified the code like
<span class="quote">>>GlobalValue *GV = cast <GlobalVariable>(M.getOrInsertGlobal(Name.getSingleStringRef(), Type::getInt32Ty(*Context)));</span >
where we used Module.getOrInsertGlobal () instead and getOrInsertGlobal()
creates new instance with "Name" if doesn't exist ,else returns the exist one .</pre>
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