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<base href="https://bugs.llvm.org/">
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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 - [ARM]"
href="https://bugs.llvm.org/show_bug.cgi?id=38435">38435</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[ARM]
</td>
</tr>
<tr>
<th>Product</th>
<td>lld
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</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>ELF
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>japaricious@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=20635" name="attach_20635" title="Output of --reproduce">attachment 20635</a> <a href="attachment.cgi?id=20635&action=edit" title="Output of --reproduce">[details]</a></span>
Output of --reproduce
These are the input object files. Observe the instruction at <main+0x2>: `bl
<__nop>`.
$ arm-none-eabi-objdump -Cd app.o | head -n11
app.o: file format elf32-littlearm
Disassembly of section .text.main:
00000000 <main>:
0: be00 bkpt 0x0000
2: f7ff fffe bl 0 <__nop>
6: be00 bkpt 0x0000
8: e7fd b.n 6 <main+0x6>
$ arm-none-eabi-objdump -Cd libasm.a
In archive libasm.a:
asm.o: file format elf32-littlearm
Disassembly of section .text:
00000000 <__nop>:
0: 4770 bx lr
When linking with LLD, <main+0x2> becomes `blx 8000050`. This instruction
causes a HardFault (SIGILL like) exception when executed. (AIUI the argument of
BLX should be a register, not an address)
$ lld -flavor gnu app.o -o app --gc-sections -L . -Bstatic --whole-archive
-lasm --no-whole-archive -Tlink.x -Bdynamic --reproduce repro.tar
$ arm-none-eabi-objdump -Cd app | head -n11
app: file format elf32-littlearm
Disassembly of section .text:
08000040 <main>:
8000040: be00 bkpt 0x0000
8000042: f000 e806 blx 8000050 <DefaultExceptionHandler>
8000046: be00 bkpt 0x0000
8000048: e7fd b.n 8000046 <main+0x6>
When linking with GNU LD, <main+0x2> becomes `bl 8000052`. This program
executes without raising an exception.
$ arm-none-eabi-ld app.o -o app --gc-sections -L . -Bstatic --whole-archive
-lasm --no-whole-archive -Tlink.x -Bdynamic
$ arm-none-eabi-objdump -Cd app | head -n11
app: file format elf32-littlearm
Disassembly of section .text:
08000040 <main>:
8000040: be00 bkpt 0x0000
8000042: f000 f806 bl 8000052 <__nop>
8000046: be00 bkpt 0x0000
8000048: e7fd b.n 8000046 <main+0x6>
Version information:
LLVM:
<a href="https://github.com/llvm-mirror/llvm/commit/0b5d0cfa8e55ac076285efb25e102597751db49c">https://github.com/llvm-mirror/llvm/commit/0b5d0cfa8e55ac076285efb25e102597751db49c</a>
LLD:
<a href="https://github.com/llvm-mirror/lld/commit/bcfc39dfc8e40fd7744828abfb4ae4f9e69dc32b">https://github.com/llvm-mirror/lld/commit/bcfc39dfc8e40fd7744828abfb4ae4f9e69dc32b</a>
GNU LD: 2.31</pre>
</div>
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