analyzer: handle static callbacks [PR97258]

analyzer: handle static callbacks [PR97258]

The analyzer's initial worklist was only populated with non-static
functions in the TU (along with those that look promising for call
summaries).  Hence some static functions that were never explicitly
called but could be called via function pointers were not being
analyzed.

This patch remedies this by ensuring that functions that escape as
function pointers get added to the worklist, if they haven't been
already.  Another fix would be to simply analyze all functions that
we have a body for, but too much of the testsuite relies on static
test functions not being directly analyzed.

gcc/analyzer/ChangeLog:
	PR analyzer/97258
	* engine.cc (impl_region_model_context::on_escaped_function): New
	vfunc.
	(exploded_graph::add_function_entry): Use m_functions_with_enodes
	to implement idempotency.
	(add_any_callbacks): New.
	(exploded_graph::build_initial_worklist): Use the above to find
	callbacks that are reachable from global initializers.
	(exploded_graph::on_escaped_function): New.
	* exploded-graph.h
	(impl_region_model_context::on_escaped_function): New decl.
	(exploded_graph::on_escaped_function): New decl.
	(exploded_graph::m_functions_with_enodes): New field.
	* region-model-reachability.cc
	(reachable_regions::reachable_regions): Replace "store" param with
	"model" param; use it to initialize m_model.
	(reachable_regions::add): When getting the svalue for the region,
	call get_store_value on the model rather than using an initial
	value.
	(reachable_regions::mark_escaped_clusters): Add ctxt param and
	use it to call on_escaped_function when a function_region escapes.
	* region-model-reachability.h
	(reachable_regions::reachable_regions): Replace "store" param with
	"model" param.
	(reachable_regions::mark_escaped_clusters): Add ctxt param.
	(reachable_regions::m_model): New field.
	* region-model.cc (region_model::handle_unrecognized_call): Update
	for change in reachable_regions ctor.
	(region_model::handle_unrecognized_call): Pass ctxt to
	mark_escaped_clusters.
	(region_model::get_reachable_svalues): Update for change in
	reachable_regions ctor.
	(region_model::get_initial_value_for_global): Read-only variables
	keep their initial values.
	* region-model.h (region_model_context::on_escaped_function): New
	vfunc.
	(noop_region_model_context::on_escaped_function): New.

gcc/testsuite/ChangeLog:
	PR analyzer/97258
	* gcc.dg/analyzer/callbacks-1.c: New test.
	* gcc.dg/analyzer/callbacks-2.c: New test.
	* gcc.dg/analyzer/callbacks-3.c: New test.