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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 - llvm-cov: macro leads to wrong code coverage"
href="https://bugs.llvm.org/show_bug.cgi?id=45844">45844</a>
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</tr>
<tr>
<th>Summary</th>
<td>llvm-cov: macro leads to wrong code coverage
</td>
</tr>
<tr>
<th>Product</th>
<td>Runtime Libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<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>libprofile library
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>yangyibiao@hust.edu.cn
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>$ clang --version
clang version 11.0.0 (/home/yibiao/.cache/yay/llvm-git/llvm-project
871beba234a83a2a02da9dedbd59b91a1bfbd7af)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ clang -O0 -fcoverage-mapping -fprofile-instr-generate=small.profraw small.c;
./a.out; llvm-profdata merge small.profraw -o small.profdata; llvm-cov show
a.out -instr-profile=small.profdata small.c > small.c.lcov; cat small.c.lcov
1| 1|#define INT_MIN (-__INT_MAX__ - 1)
2| |
3| 1|int f(unsigned int u) {
4| 1| return (-(int)(u-1U))-1;
5| 1|}
6| |
7| 1|int main () {
8| 1| if(f(__INT_MAX__+1U) != INT_MIN)
9| 1| return 0;
10| 1| return 1;
11| 1|}
Line #9 is wrongly marked as executed. This line is not executed in practice as
in lldb this line is not reached as follows:
$ clang -g small.c; lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Decov/a.out' (x86_64).
(lldb) b 9
Breakpoint 1: where = a.out`main + 36 at small.c:9:5, address =
0x0000000000401154
(lldb) run
Process 405847 launched: '/home/yibiao/Decov/a.out' (x86_64)
Process 405847 exited with status = 1 (0x00000001)
$ cat small.c
#define INT_MIN (-__INT_MAX__ - 1)
int f(unsigned int u) {
return (-(int)(u-1U))-1;
}
int main () {
if(f(__INT_MAX__+1U) != INT_MIN)
return 0;
return 1;
}</pre>
</div>
</p>
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