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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: wrong coverage for statement in a loop"
href="https://bugs.llvm.org/show_bug.cgi?id=45845">45845</a>
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<th>Summary</th>
<td>llvm-cov: wrong coverage for statement in a loop
</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>
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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>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>libprofile library
</td>
</tr>
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<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| |void foo(int y)
2| 1|{
3| 1| if (y)
4| 0| exit(1);
5| 1| exit(0);
6| 1|}
7| |
8| |void main()
9| 1|{
10| 1| int x = 1, y = 0;
11| 2| while(1) {
12| 1| if (x)
13| 1| foo(y);
14| 1| x++;
15| 1| }
16| 1|}
****
Line 14 is wrongly marked as executed. However, the program exit in foo
function. Thus, Line 11 is not executed. This is confirmed in lldb as follow:
$ clang -w -g small.c; lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Decov/a.out' (x86_64).
(lldb) b 14
Breakpoint 1: where = a.out`main + 40 at small.c:14:6, address =
0x0000000000401188
(lldb) r
Process 446347 launched: '/home/yibiao/Decov/a.out' (x86_64)
Process 446347 exited with status = 0 (0x00000000)
We can find that process exit thus, the breakpoint at Line 14 is not hit by
lldb.</pre>
</div>
</p>
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