Re: i386 ddb trace stopped working with gcc48

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

On 21 Apr 2014, at 14:39, J. Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost> 
wrote:

> Since i386 switched to gcc48 ddb trace no longer works:
> 
> fatal breakpoint trap in supervisor mode
> trap type 1 code 0 eip c02802f4 cs 8 eflags 202 cr2 bbbab0c4 ilevel 8 esp 800
> curlwp 0xc5a9fd20 pid 0 lid 2 lowest kstack 0xdd3b22c0
> Stopped in pid 0.2 (system) at  netbsd:breakpoint+0x4:  popl    %ebp
> db{0}> bt
> breakpoint(c0e661c0,3f8,0,0,c61c5158,c170dacc,c6188000,c5f396c0,c5f39748,dd3b4edc)
>  at netbsd:breakpoint+0x4
> 
> Thats all, never get more than one line.
> The i386_frame from %ebp = dd25ef30 looks like:
> 
> dd25ef30:       7ff           <= should be the previous frame
> dd25ef34:       c0277cc1      <= comintr+0x53e (caller of breakpoint)
> dd25ef38:       c0e661c0
> 
> Ideas anyone?

Some further notes:

- The function prologue has changed as

        -push   %ebp
        -mov    %esp,%ebp
         sub    $0x14,%esp

         call   ...
        -leave  
        +add    $0x14,%esp
         ret    

- With -fno-omit-frame-pointer all is well.

Does it ring any bell?

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig 
(Germany)