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Re: Designs for better debug info in GCC
Alexandre Oliva wrote:
On Nov 8, 2007, Robert Dewar <dewar@adacore.com> wrote:
My general feelings on this subject:
1. I don't think we should care much about the ability to
*SET* values of variables in optimized code.
Indeed. We should care about correctness of debug information, and
then this ability will come naturally ;-)
Not really, there are optimizations that will still allow
reading the value of a variable, but not setting it, and
I think it is just fine to do these optimizations. For
instance if we have
b = a;
the optimizer may not do a copy, it may simply know that
b and a values are in the same place. This does not stand
in the way of reading the value, but it does make it
impossible to write a or b.
Similarly, if the optimizer does test replacement, and
knows that the value of a can be obtained by evaluating
some expression, the debugger can read the value, but
may not be able to set it.
3. The quality of code at -O0 is really terrible
That's a feature, no?