[llvm-bugs] [Bug 48264] New: llvm-cov: wrong code coverage for statements before fork()

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=48264

            Bug ID: 48264
           Summary: llvm-cov: wrong code coverage for statements before
                    fork()
           Product: Runtime Libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: libprofile library
          Assignee: unassignedbugs at nondot.org
          Reporter: yangyibiao at hust.edu.cn
                CC: llvm-bugs at lists.llvm.org

$ cat test.c
int main()
{
  int a = 1, c = 0;
  c = c-a;
  while(c>1)
  {
    c = c+a;
  }
  int pid = fork();
  return 0;
}


$ clang -O0 -w -fcoverage-mapping -fprofile-instr-generate=test.profraw test.c;
./a.out; llvm-profdata merge test.profraw -o test.profdata; llvm-cov show a.out
-instr-profile=test.profdata test.c > test.c.lcov; cat test.c.lcov
    1|       |int main()
    2|      2|{
    3|      2|  int a = 1, c = 0;
    4|      2|  c = c-a;
    5|      2|  while(c>1)
    6|      0|  {
    7|      0|    c = c+a;
    8|      0|  }
    9|      2|  int pid = fork();
   10|      2|  return 0;
   11|      2|}



##############
We can found that Line#3 and Line#4 are both wrongly marked as executed twice. 
When debug this program in lldb, Line#3 and Line#4 only hit once.

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