static void
insert_trap_and_remove_trailing_statements (gimple_stmt_iterator *si_p, tree op)
{
/* We want the NULL pointer dereference to actually occur so that
code that wishes to catch the signal can do so.
If the dereference is a load, then there's nothing to do as the
LHS will be a throw-away SSA_NAME and the RHS is the NULL dereference.
If the dereference is a store and we can easily transform the RHS,
then simplify the RHS to enable more DCE. Note that we require the
statement to be a GIMPLE_ASSIGN which filters out calls on the RHS. */
gimple stmt = gsi_stmt (*si_p);
if (walk_stmt_load_store_ops (stmt, (void *)op, NULL, check_loadstore)
&& is_gimple_assign (stmt)
&& INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (stmt))))
{
/* We just need to turn the RHS into zero converted to the proper
type. */
tree type = TREE_TYPE (gimple_assign_lhs (stmt));
gimple_assign_set_rhs_code (stmt, INTEGER_CST);
gimple_assign_set_rhs1 (stmt, fold_convert (type, integer_zero_node));
update_stmt (stmt);
}
gimple new_stmt
= gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
gimple_seq seq = NULL;
gimple_seq_add_stmt (&seq, new_stmt);
/* If we had a NULL pointer dereference, then we want to insert the
__builtin_trap after the statement, for the other cases we want
to insert before the statement. */
if (walk_stmt_load_store_ops (stmt, (void *)op,
check_loadstore,
check_loadstore))
gsi_insert_after (si_p, seq, GSI_NEW_STMT);
else
gsi_insert_before (si_p, seq, GSI_NEW_STMT);
/* We must remove statements from the end of the block so that we
never reference a released SSA_NAME. */
basic_block bb = gimple_bb (gsi_stmt (*si_p));
for (gimple_stmt_iterator si = gsi_last_bb (bb);
gsi_stmt (si) != gsi_stmt (*si_p);
si = gsi_last_bb (bb))
{
stmt = gsi_stmt (si);
unlink_stmt_vdef (stmt);
gsi_remove (&si, true);
release_defs (stmt);
}
}
/* Look into pointer pointed to by GSIP and figure out what interesting side
effects it has. */
static void
check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa)
{
gimple stmt = gsi_stmt (*gsip);
if (is_gimple_debug (stmt))
return;
if (dump_file)
{
fprintf (dump_file, " scanning: ");
print_gimple_stmt (dump_file, stmt, 0, 0);
}
if (gimple_has_volatile_ops (stmt)
&& !gimple_clobber_p (stmt))
{
local->pure_const_state = IPA_NEITHER;
if (dump_file)
fprintf (dump_file, " Volatile stmt is not const/pure\n");
}
/* Look for loads and stores. */
walk_stmt_load_store_ops (stmt, local,
ipa ? check_ipa_load : check_load,
ipa ? check_ipa_store : check_store);
if (gimple_code (stmt) != GIMPLE_CALL
&& stmt_could_throw_p (stmt))
{
if (cfun->can_throw_non_call_exceptions)
{
if (dump_file)
fprintf (dump_file, " can throw; looping\n");
local->looping = true;
}
if (stmt_can_throw_external (stmt))
{
if (dump_file)
fprintf (dump_file, " can throw externally\n");
local->can_throw = true;
}
else
if (dump_file)
fprintf (dump_file, " can throw\n");
}
switch (gimple_code (stmt))
{
case GIMPLE_CALL:
check_call (local, stmt, ipa);
break;
case GIMPLE_LABEL:
if (DECL_NONLOCAL (gimple_label_label (stmt)))
/* Target of long jump. */
{
if (dump_file)
fprintf (dump_file, " nonlocal label is not const/pure\n");
local->pure_const_state = IPA_NEITHER;
}
break;
case GIMPLE_ASM:
if (gimple_asm_clobbers_memory_p (stmt))
{
if (dump_file)
fprintf (dump_file, " memory asm clobber is not const/pure\n");
/* Abandon all hope, ye who enter here. */
local->pure_const_state = IPA_NEITHER;
}
if (gimple_asm_volatile_p (stmt))
{
if (dump_file)
fprintf (dump_file, " volatile is not const/pure\n");
/* Abandon all hope, ye who enter here. */
local->pure_const_state = IPA_NEITHER;
local->looping = true;
}
return;
default:
break;
}
}
