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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Function symbol from assembler misses lowest bit set in Thumb mode"
href="https://bugs.llvm.org/show_bug.cgi?id=44860">44860</a>
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<th>Summary</th>
<td>Function symbol from assembler misses lowest bit set in Thumb mode
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>10.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Backend: ARM
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>stefan@agner.ch
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, peter.smith@linaro.org, Ties.Stuij@arm.com
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=23113" name="attach_23113" title="reproducer assembly">attachment 23113</a> <a href="attachment.cgi?id=23113&action=edit" title="reproducer assembly">[details]</a></span>
reproducer assembly
Using the .type directive to mark a label as a function in Thumb mode does not
get the correct symbol table entry.
.syntax unified
.text
.thumb
__setup_mmu:
it ne
blne __setup_mmu
.type __setup_mmu, %function // Move this line before __setup_mmu for
correct behaviour.
llvm-mc --triple=armv7a-linux-gnueabihf blne.s -filetype=obj -o blne.o
--arm-add-build-attributes
llvm-readelf --symbols blne.o
Symbol table '.symtab' contains 3 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 NOTYPE LOCAL DEFAULT 2 $t.0
2: 00000000 0 FUNC LOCAL DEFAULT 2 __setup_mmu
This has been observed when trying to build Linux for 32-bit ARM in Thumb2
mode. When the object file gets linked, the linker inserts a blx instruction
which switches the CPU instruction set...</pre>
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