[llvm-bugs] [Bug 45820] New: Wrong line table information at -Og

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45820

            Bug ID: 45820
           Summary: Wrong line table information at -Og
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: DebugInfo
          Assignee: unassignedbugs at nondot.org
          Reporter: ditaliano at apple.com
                CC: jdevlieghere at apple.com, keith.walker at arm.com,
                    llvm-bugs at lists.llvm.org,
                    paul_robinson at playstation.sony.com

short a, b;
void(c)(d) {}
short(e)(d) { return d; }
static short(f)(d) {}
short g() {
  int l_284[2][3][6];
  for (; a >= 0;) {
    if (e(0 <= 0))
      return 1;
    for (;;) {
      l_284[1][2][5] = 0;
      break;
    }
    c(f);
    f(l_284);
    b = l_284[1][1][4];
  }
}
int main() { g(); }

####


Process 16744 stopped
* thread #1: tid = 16744, 0x0000000000401181 drama.out`main + 1 at a.c:19, name
= 'drama.out', stop reason = breakpoint 1.1
    frame #0: 0x0000000000401181 drama.out`main + 1 at a.c:19
   16       b = l_284[1][1][4];
   17     }
   18   }
-> 19   int main() { g(); }
(lldb) s
Process 16744 stopped
* thread #1: tid = 16744, 0x0000000000401137 drama.out`g + 7 at a.c:7, name =
'drama.out', stop reason = step in
    frame #0: 0x0000000000401137 drama.out`g + 7 at a.c:7
   4    static short(f)(d) {}
   5    short g() {
   6      int l_284[2][3][6];
-> 7      for (; a >= 0 {
   8        if (e(0 <= 0))
   9          return 1;
   10       for (; {
(lldb) s
Process 16744 stopped
* thread #1: tid = 16744, 0x0000000000401122 drama.out`e(d=1) + 2 at a.c:3,
name = 'drama.out', stop reason = step in
    frame #0: 0x0000000000401122 drama.out`e(d=1) + 2 at a.c:3
   1    short a, b;
   2    void(c)(d) {}
-> 3    short(e)(d) { return d; }
   4    static short(f)(d) {}
   5    short g() {
   6      int l_284[2][3][6];
   7      for (; a >= 0 {
(lldb) s
Process 16744 stopped
* thread #1: tid = 16744, 0x0000000000401150 drama.out`g + 32 at a.c:11, name =
'drama.out', stop reason = step in
    frame #0: 0x0000000000401150 drama.out`g + 32 at a.c:11
   8        if (e(0 <= 0))
   9          return 1;
   10       for (; {
-> 11         l_284[1][2][5] = 0;
   12         break;
   13       }
   14       c(f);

The line 9 should be always hit and the program should exit never executing
lines [10:12], however we see that line 11 is hit after returning from function
e. For some reason it only reproduces on Linux, I haven't investigated yet.

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