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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [ASM] cannot set unwind info for eflags register"
href="https://llvm.org/bugs/show_bug.cgi?id=23033">23033</a>
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<th>Summary</th>
<td>[ASM] cannot set unwind info for eflags register
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>3.6
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>FreeBSD
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>alexandre.martins@stormshield.eu
</td>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
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</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=14102" name="attach_14102" title="sample code">attachment 14102</a> <a href="attachment.cgi?id=14102&action=edit" title="sample code">[details]</a></span>
sample code
I currently trying to make a bare c++ new kernel.
In one of piece of assembly code, I play with eflags register, and i want to
provide unwinding info.
However, clang rejects the use of eflags as register, but it works with gcc
$ clang36 -m32 -c check.s
check.s:11:23: error: invalid register name
.cfi_offset eflags, 0
^
check.s:16:24: error: invalid register name
.cfi_restore eflags
^
$ gcc49 -m32 -c check.s
$ echo $?
0
$ readelf -wf check.o
Contenu de la section .eh_frame :
00000000 00000014 00000000 CIE
Version: 1
Augmentation: "zR"
Code alignment factor: 1
Data alignment factor: -4
Return address column: 8
Augmentation data: 1b
DW_CFA_def_cfa: r4 (esp) ofs 4
DW_CFA_offset: r8 (eip) at cfa-4
DW_CFA_nop
DW_CFA_nop
00000018 0000001c 0000001c FDE cie=00000000 pc=00000000..00000007
DW_CFA_advance_loc: 1 to 00000001
DW_CFA_def_cfa_offset: 8
DW_CFA_advance_loc: 2 to 00000003
DW_CFA_def_cfa_register: r5 (ebp)
DW_CFA_advance_loc: 1 to 00000004
DW_CFA_offset: r9 (eflags) at cfa+0
DW_CFA_advance_loc: 1 to 00000005
DW_CFA_restore: mauvais registre : r9 (eflags)
DW_CFA_advance_loc: 1 to 00000006
DW_CFA_def_cfa: r4 (esp) ofs 4
Can be possible to add support of this register ?</pre>
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