Question on cgraph_node::force_output

[Erick Ochoa]

Hi,

I am looking at tree-ssa-structalias.c looking at what makes a
function nonlocal during IPA-PTA. I am having some problems
understanding force_output and when it is set or unset.

1. What is the meaning of force_output? cgraph.h gives an example that
force output means that the symbol might be used in an invisible way.
I believe this means some sort of "unanalyzable" way. However, for a
few tests I've made, all functions have the field force_output set to
true.
2. Does this value depend on some other pass?

At the moment, I am looking at this field within my own passes
(IPA_PASS and SIMPLE_IPA_PASS), but I would like to inspect the
dump_file(s) which show information about force_output to make sure
that it doesn't depend on pass order or even my own flags.

3. What flags should I use to inspect force_output?

Thanks!