Re: [RFC/RFA?] Should break FILE:LINENO skip prologue?

Michael Snyder
2008-01-10T21:47:24Z

On Thu, 2008-01-10 at 12:47 +0100, Eric Botcazou wrote:
> > If generating the right location information for -O0 is too difficult,
> > perhaps the compiler should make life easier for itself and disable
> > scheduling instructions into the prologue?
>
> What do you call "scheduling instructions into the prologue" exactly?

I wouldn't speak for Mark, but personally I could imagine, say,
that at -O0 gcc might treat the prologue (whatever we decide
that means) as an atom, and not allow non-prologue instructions
to be shuffled into it.

The next question would be, are automatic variable initializations
part of that atom?

I might say that I personally rarely need to debug the "formal"
prologue (that part that would exist in any (framed/frameless)
function independent of automatics initialization), and when I
do, it's as a tools developer, not as an ordinary debugger user.
Therefore I don't mind having to do something "special".

But the initializations are another story, especially if they
require non-trivial stuff like computations or function calls.
Any user might reasonably want to debug those. So any change
that made it difficult for a user to debug those (say by forcing
him to set a break at the label) would go against the grain
for me.