Re: [Valgrind-developers] Merging stage2.c and vg_main.c [was Re: tool-specific CLOs] (fwd)

[Nicholas N. <nj...@ca...>]

On Wed, 21 Jan 2004, Jeremy Fitzhardinge wrote:

> m_state_static is a holdover from the old code, and isn't really
> necessary anymore.  It's just used to bootstrap the initial thread
> state, but we could do it more directly.

I can see how to constant-propagate things so it's not needed, but that
raises an interesting question -- it seems most of the registers in
baseBlock never get properly initialised as such.  It seems %esp and %eip
and the fp-state are initialised, but the rest of them are never set in
m_state_static before it gets copied into the baseBlock;  thus, they get
set to zero (because m_state_static is a static struct and thus zeroed
initially).

I'm guessing that careful m_state_static setup was necessary pre-FV, when
Valgrind got control some time after the program had started.  But now it
gets control before any meaningful values are put in the GP regs (except
%esp), so their contents can be junk?

N