PR analyzer/101503 reports an assertion failure due to an unexpected
"UNKNOWN" value (due to using --param analyzer-max-svalue-depth=0).
This patch fixes this by rejecting attempts to purge state involving
unknown/poisoned svalues (in region_model::purge_state_involving),
as these svalues should not have state associated with them - they
are singletons w.r.t each type.
To be more systematic about this, the patch also introduces a new
svalue::can_have_associated_state_p which returns false for
unknown/poisoned svalues, so that we can reject adding constraints
or sm-state on them, or building various kinds of svalue in terms
of them (e.g. unary ops, binary ops, etc).
gcc/analyzer/ChangeLog:
PR analyzer/101503
* constraint-manager.cc (constraint_manager::add_constraint): Use
can_have_associated_state_p rather than testing for unknown.
(constraint_manager::get_or_add_equiv_class): Likewise.
* program-state.cc (sm_state_map::set_state): Likewise.
(sm_state_map::impl_set_state): Add assertion.
* region-model-manager.cc
(region_model_manager::maybe_fold_unaryop): Handle poisoned
values.
(region_model_manager::maybe_fold_binop): Move handling of unknown
values...
(region_model_manager::get_or_create_binop): ...to here, and
generalize to use can_have_associated_state_p.
(region_model_manager::maybe_fold_sub_svalue): Use
can_have_associated_state_p rather than testing for unknown.
(region_model_manager::maybe_fold_repeated_svalue): Use unknown
when the size or repeated value is "unknown"/"poisoned".
* region-model.cc (region_model::purge_state_involving): Reject
attempts to purge unknown/poisoned svalues, as these svalues
should not have state associated with them.
* svalue.cc (sub_svalue::sub_svalue): Assert that we're building
on top of an svalue with can_have_associated_state_p.
(repeated_svalue::repeated_svalue): Likewise.
(bits_within_svalue::bits_within_svalue): Likewise.
* svalue.h (svalue::can_have_associated_state_p): New.
(unknown_svalue::can_have_associated_state_p): New.
(poisoned_svalue::can_have_associated_state_p): New.
(unaryop_svalue::unaryop_svalue): Assert that we're building on
top of an svalue with can_have_associated_state_p.
(binop_svalue::binop_svalue): Likewise.
(widening_svalue::widening_svalue): Likewise.
gcc/testsuite/ChangeLog:
PR analyzer/101503
* gcc.dg/analyzer/pr101503.c: New test.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>