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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - WebAssembly miscompiles global structs with multiple data members"
href="https://llvm.org/bugs/show_bug.cgi?id=25931">25931</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>WebAssembly miscompiles global structs with multiple data members
</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>Common Code Generator Code
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jfb@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>(filing under lib/CodeGen, since we don't have a component for WebAssembly at
the moment)
The following GCC torture test:
<a href="https://github.com/gcc-mirror/gcc/blob/master/gcc/testsuite/gcc.c-torture/execute/20010924-1.c">https://github.com/gcc-mirror/gcc/blob/master/gcc/testsuite/gcc.c-torture/execute/20010924-1.c</a>
Has the following code:
struct {
char a1c;
char *a1p;
} a1 = {
'4',
"62"
};
struct {
char a2c;
char a2p[2];
} a2 = {
'v',
"cq"
};
/* The tests. */
struct {
char a3c;
char a3p[];
} a3 = {
'o',
"wx"
};
struct {
char a4c;
char a4p[];
} a4 = {
'9',
{ 'e', 'b' }
};
Which WebAssembly's backend miscompiles as:
.str:
.asciz "62"
.size .str, 3
.type a1,@object # @a1
.globl a1
.align 2
a1:
.int8 52 # 0x34
.zero 3
.int32 .str
.size a1, 8
.type a2,@object # @a2
.globl a2
a2:
.int8 118 # 0x76
.ascii "cq"
.size a2, 3
.type a3,@object # @a3
.globl a3
a3:
.int8 111 # 0x6f
.asciz "wx"
.size a3, 4
.type a4,@object # @a4
.globl a4
a4:
.int8 57 # 0x39
.ascii "eb"
.size a4, 3
Note the missing initialization (but surprisingly, correct size!).</pre>
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