analyzer: fix ICE on memset of untracked region [PR105057]

analyzer: fix ICE on memset of untracked region [PR105057]

In r12-7809-g5f6197d7c197f9d2b7fb2e1a19dac39a023755e8 I added an
optimization to avoid tracking the state of certain memory regions
in the store.

Unfortunately, I didn't cover every way in which
store::get_or_create_cluster can be called for a base region, leading
to assertion failure ICEs in -fanalyzer on certain function calls
with certain params.

I've worked through all uses of store::get_or_create_cluster and found
four places where the assertion could fire.

This patch fixes them, and adds regression tests where possible.

gcc/analyzer/ChangeLog:
	PR analyzer/105057
	* store.cc (binding_cluster::make_unknown_relative_to): Reject
	attempts to create a cluster for untracked base regions.
	(store::set_value): Likewise.
	(store::fill_region): Likewise.
	(store::mark_region_as_unknown): Likewise.

gcc/testsuite/ChangeLog:
	PR analyzer/105057
	* gcc.dg/analyzer/fread-2.c: New test, as a regression test for
	ICE in store::set_value on untracked base region.
	* gcc.dg/analyzer/memset-2.c: Likewise, for ICE in
	store::fill_region.
	* gcc.dg/analyzer/strcpy-2.c: Likewise, for ICE in
	store::mark_region_as_unknown.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>