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Date: Sat, 29 Oct 2011 07:42:00 -0000
From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: asmwarrior <asmwarrior@gmail.com>
Cc: gdb@sourceware.org
Subject: Re: Why running the next command will jump back to the previous line position
Message-ID: <20111029072237.GA3977@host1.jankratochvil.net>
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On Sat, 29 Oct 2011 09:11:25 +0200, asmwarrior wrote:
[...]
> This was quite strange, it looks like the instruction will return to some
> previous position. (I guess that the destructor of the "std::map" was
> called.

yes, objdump -dSC shows there:

    std::map<int, std::string> m;
  400bab:       48 8d 45 b0             lea    -0x50(%rbp),%rax
  400baf:       48 89 c7                mov    %rax,%rdi
  400bb2:       e8 43 00 00 00          callq  400bfa <std::map<int, std::string, std::less<int>, std::allocator<std::pair<int const, std::string> > >::~map()>
  400bb7:       89 d8                   mov    %ebx,%eax


> My question is: This behavior is quite anti-friendly,

Maybe GCC could produce there DW_LNS_negate_stmt so that the variable
declaration line is still shown in backtraces (if the destructor crashes) but
it is skipped over during stepping/nexting; but GDB currently would not show
such line in backtraces, GCC currently does not produce DW_LNS_negate_stmt
anyway.



Regards,
Jan