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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 - clang-9 -fsanitize-coverage=trace-pc leaves temporary symbols"
href="https://bugs.llvm.org/show_bug.cgi?id=43123">43123</a>
</td>
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<th>Summary</th>
<td>clang-9 -fsanitize-coverage=trace-pc leaves temporary symbols
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>9.0
</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>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>arnd@linaro.org
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
</td>
</tr></table>
<p>
<div>
<pre>The combination of the -fsanitize-coverage=trace-pc and asm-goto sometimes
leaves undefined references:
<a href="https://godbolt.org/z/f-c4C3">https://godbolt.org/z/f-c4C3</a>
$ cat test.c
enum { false, true } arch_static_branch() {
_Bool branch = 0;
int *key = 0;
asm goto("1:\n\tnop\n\t.pushsection __jump_table, \"aw\"\n\t.word b, "
"%l[l_yes], %c0\n\t.popsection\n\t"
:
: "i"(&key[branch])
:
: l_yes);
return false;
l_yes:
return true;
}
void __raw_writel(volatile int *addr) {
int val = 0;
asm("str %1, %0" : : "Qo"(*addr), "r"(val));
}
void *imx_pmx_set_one_pin_mmio_ipctl_2;
void *imx_pmx_set_one_pin_mmio_ipctl_1;
void imx_pmx_set_one_pin_mmio() {
if (imx_pmx_set_one_pin_mmio_ipctl_2) {
__asm__("mcr p15, 0, %0, c7, c10, 4" : : "r"(0) : "memory");
__raw_writel(imx_pmx_set_one_pin_mmio_ipctl_2);
}
else {
__asm__("mcr p15, 0, %0, c7, c10, 4" : : "r"(0) : "memory");
__raw_writel(imx_pmx_set_one_pin_mmio_ipctl_1);
}
{ arch_static_branch(); }
}
$ clang-9 --target=arm-linux-gnueabi -fsanitize-coverage=trace-pc -O2
-march=armv6k -Wall -c test.c
error: Undefined temporary symbol
$ clang-9 --version
clang version 9.0.0-svn369744-1~exp1~20190823103928.28 (branches/release_90)
The symbol comes from this part of the assembler output:
bl __sanitizer_cov_trace_pc
@APP
@NO_APP
@APP
nop
@NO_APP
b .LBB2_1
pop {r4, r5, r6, r10, r11, pc}
.LBB2_1 is referenced here but never defined.</pre>
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