Re: The 'cold' function attribute and GDB

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 2 May 2019 00:38:49 -0700
> From: Kevin Buettner <kevinb@redhat.com>
> Cc: gdb-patches@sourceware.org, Simon Marchi <simark@simark.ca>
> 
> Can you show me what is printed for the following commands?
> 
> disassemble print_vectorlike
> x/3i print_vectorlike
> b print_vectorlike
> 
> For the disassemble command, I expect both ranges to be displayed. 
> The x and b commands should print insns / set a breakpoint on the entry
> pc (which should NOT be the cold address) of the function.  If one or more
> of these things aren't happening, then something is going wrong
> somewhere.

Here:

  (gdb) disassemble /m print_vectorlike
  Dump of assembler code for function print_vectorlike:
  Address range 0x11d6521 to 0x11d81d6:
  1367	{
     0x011d6521 <+0>:	push   %ebp
     0x011d6522 <+1>:	mov    %esp,%ebp
     0x011d6524 <+3>:	push   %edi
     0x011d6525 <+4>:	push   %esi
     0x011d6526 <+5>:	push   %ebx
     0x011d6527 <+6>:	sub    $0x7c,%esp
  [...]
  Address range 0x12e1ce5 to 0x12e1f3b:
  1824	      emacs_abort ();
     0x012e1f36 <+593>:	call   0x12e7b40 <emacs_abort>

  End of assembler dump.

  (gdb) x/3i print_vectorlike
     0x11d6521 <print_vectorlike>:        push   %ebp
     0x11d6522 <print_vectorlike+1>:      mov    %esp,%ebp
     0x11d6524 <print_vectorlike+3>:      push   %edi
  (gdb) break print_vectorlike
  Breakpoint 1 at 0x11d6521: file print.c, line 1367.

Seems to be according to your expectations.

Btw, if I use a source line number whose code is in the 'cold' area,
then I see this:

  (gdb) break print.c:1824
  Breakpoint 1 at 0x12e1f36: file print.c, line 1824.
  (gdb) info line print.c:1824
  Line 1824 of "print.c"
     starts at address 0x12e1f36 <print_vectorlike.cold.65+593>
     and ends at 0x12e1f3b <print_vectorlike.cold.65+598>.

Thanks.