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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [-cxx-abi microsoft] C++ objects passed by value are constructed in place on the argument stack slots"
href="http://llvm.org/bugs/show_bug.cgi?id=16226">16226</a>
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<th>Summary</th>
<td>[-cxx-abi microsoft] C++ objects passed by value are constructed in place on the argument stack slots
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>unspecified
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
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<th>Status</th>
<td>NEW
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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>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>reid.kleckner@gmail.com
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<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
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<pre>This is kind of a big problem, since I don't know how to represent this in LLVM
IR. I'm also not sure how to file this, since it cuts across the ABI lowering
in Clang and LLVM.
MSVC lowers this code like this:
struct S {
S();
~S();
int a, b;
};
void foo(S s) {
// ~S() is called before return
}
void bar() {
S t;
foo(t); // S(const S &) is called on t.
}
LLVM arguments are always passed by value, and there's no way to talk about the
stack space that they may or may not use depending on target architecture.
Would it make sense to invent some kind of special alloca to handle this case?</pre>
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