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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wasm: __cxa_atexit called with wrong signature function for global reference temporaries"
href="https://bugs.llvm.org/show_bug.cgi?id=45876">45876</a>
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<th>Summary</th>
<td>wasm: __cxa_atexit called with wrong signature function for global reference temporaries
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<th>Product</th>
<td>libraries
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>All
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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>Backend: WebAssembly
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>vladimir@pobox.com
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<th>CC</th>
<td>dan433584@gmail.com, llvm-bugs@lists.llvm.org
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<pre>The following snippet (from Dan Gohman):
struct B { B(); ~B(); };
namespace test {
const B b1 = B();
const B &b2 = B();
}
shows the problem -- the global_var_init that's generated to initialize the b2
reference is created with a call to __cxa_atexit that directly passes the
destructor. A dtor's function signature doesn't match what __cxa_atexit needs,
so there's a signature mismatch at execution time (at app exit).
For normal global destructors, there's a path that explicitly checks for
whether cxa_atexit can be called directly with a destructor, and if not,
generates a helper:
<a href="https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CGDeclCXX.cpp#L106">https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CGDeclCXX.cpp#L106</a>
But the reference temporary destructor goes through here (I think), which
doesn't check if the platform allows destructors to be passed to cxa_atexit:
<a href="https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CGExpr.cpp#L347">https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CGExpr.cpp#L347</a>
Long-form discussion here:
<a href="https://bytecodealliance.zulipchat.com/#narrow/stream/206238-general/topic/__funcs_on_exit.20indirect.20call.20type.20mismatch.20with.20wasi-sdk">https://bytecodealliance.zulipchat.com/#narrow/stream/206238-general/topic/__funcs_on_exit.20indirect.20call.20type.20mismatch.20with.20wasi-sdk</a></pre>
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