[PATCH] D19630: Debug info: Support DWARF4 bitfields via DW_AT_data_bit_offset.

[mattias.v.eriksson@ericsson.com via llvm-commits]

materi added a subscriber: materi.
materi added a comment.

Hi!

I am debugging an issue with bitfields and debug info and found that this commit is where the problems begin.

The file tmp.c:

  struct fields
  {
    unsigned int a : 1;
    unsigned int b : 1;
  } f;
  
  int main ()
  {
    f.a = 1;
    return 0;
  }

Built with top-of-tree clang and run in gdb:

  gdb a.out
  GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1
  ...
  Reading symbols from a.out...done.
  (gdb) break main
  Breakpoint 1 at 0x40058d: file tmp.c, line 9.
  (gdb) run
  Starting program: a.out 
  
  Breakpoint 1, main () at tmp.c:9
  9         f.a = 1;
  (gdb) display f
  1: f = {a = 0, b = 0}
  (gdb) n
  10        return 0;
  1: f = {a = 1, b = 1}                 <<<--- Unexpected value of b!
  (gdb) x &f
  0x402024 <f>:   0x00000001
  (gdb) 

Should I write a bug report in bugzilla?


Repository:
  rL LLVM

http://reviews.llvm.org/D19630