<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [WebAssembly] Exception specifications don't work in Emscripten EH & Wasm EH (except for throw())"
href="https://bugs.llvm.org/show_bug.cgi?id=50396">50396</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[WebAssembly] Exception specifications don't work in Emscripten EH & Wasm EH (except for throw())
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: WebAssembly
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>aheejin@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>alonzakai@gmail.com, dschuff@google.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>It turns out Emscripten EH hasn't supported dynamic exception specification all
along. For example, the program prints "Incorrect", which it shouldn't:
```
#include <stdio.h>
void test() throw(float) { throw 3; }
int main() {
try {
test();
} catch (int n) {
printf("Incorrect\n");
}
return 0;
}
```
It supports `throw()` correctly, but for other types within `throw(..)`,
Emscripten EH currently allows all types to be thrown.
We are working on the new wasm EH based on the the wasm spec
(<a href="https://github.com/WebAssembly/exception-handling">https://github.com/WebAssembly/exception-handling</a>), but this currently has the
same limitation: it also only supports `throw()` and not other `throw(..)`.
For both Emscripten EH (the current EH) and the new wasm EH (currently
experimental and new browser support is necessary) the exception spec except
for `throw()` has never worked, and we don't have a short-term plan to fix this
in near future. Patches are welcome though.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>