unsigned HOST_WIDE_INT
compute_builtin_object_size (tree ptr, int object_size_type)
{
gcc_assert (object_size_type >= 0 && object_size_type <= 3);
if (! offset_limit)
init_offset_limit ();
if (TREE_CODE (ptr) == ADDR_EXPR)
return addr_object_size (ptr, object_size_type);
else if (TREE_CODE (ptr) == CALL_EXPR)
{
tree arg = pass_through_call (ptr);
if (arg)
return compute_builtin_object_size (arg, object_size_type);
else
return alloc_object_size (ptr, object_size_type);
}
else if (TREE_CODE (ptr) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (ptr))
&& object_sizes[object_size_type] != NULL)
{
if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr)))
{
struct object_size_info osi;
bitmap_iterator bi;
unsigned int i;
if (dump_file)
{
fprintf (dump_file, "Computing %s %sobject size for ",
(object_size_type & 2) ? "minimum" : "maximum",
(object_size_type & 1) ? "sub" : "");
print_generic_expr (dump_file, ptr, dump_flags);
fprintf (dump_file, ":\n");
}
osi.visited = BITMAP_ALLOC (NULL);
osi.reexamine = BITMAP_ALLOC (NULL);
osi.object_size_type = object_size_type;
osi.depths = NULL;
osi.stack = NULL;
osi.tos = NULL;
/* First pass: walk UD chains, compute object sizes that
can be computed. osi.reexamine bitmap at the end will
contain what variables were found in dependency cycles
and therefore need to be reexamined. */
osi.pass = 0;
osi.changed = false;
collect_object_sizes_for (&osi, ptr);
/* Second pass: keep recomputing object sizes of variables
that need reexamination, until no object sizes are
increased or all object sizes are computed. */
if (! bitmap_empty_p (osi.reexamine))
{
bitmap reexamine = BITMAP_ALLOC (NULL);
/* If looking for minimum instead of maximum object size,
detect cases where a pointer is increased in a loop.
Although even without this detection pass 2 would eventually
terminate, it could take a long time. If a pointer is
increasing this way, we need to assume 0 object size.
E.g. p = &buf[0]; while (cond) p = p + 4; */
if (object_size_type & 2)
{
osi.depths = xcalloc (num_ssa_names, sizeof (unsigned int));
osi.stack = xmalloc (num_ssa_names * sizeof (unsigned int));
osi.tos = osi.stack;
osi.pass = 1;
/* collect_object_sizes_for is changing
osi.reexamine bitmap, so iterate over a copy. */
bitmap_copy (reexamine, osi.reexamine);
EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
if (bitmap_bit_p (osi.reexamine, i))
check_for_plus_in_loops (&osi, ssa_name (i));
free (osi.depths);
osi.depths = NULL;
free (osi.stack);
osi.stack = NULL;
osi.tos = NULL;
}
do
{
osi.pass = 2;
osi.changed = false;
/* collect_object_sizes_for is changing
osi.reexamine bitmap, so iterate over a copy. */
bitmap_copy (reexamine, osi.reexamine);
EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
if (bitmap_bit_p (osi.reexamine, i))
{
collect_object_sizes_for (&osi, ssa_name (i));
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Reexamining ");
print_generic_expr (dump_file, ssa_name (i),
dump_flags);
fprintf (dump_file, "\n");
}
}
}
while (osi.changed);
BITMAP_FREE (reexamine);
}
EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi)
bitmap_set_bit (computed[object_size_type], i);
/* Debugging dumps. */
if (dump_file)
{
EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi)
if (object_sizes[object_size_type][i]
!= unknown[object_size_type])
{
print_generic_expr (dump_file, ssa_name (i),
dump_flags);
fprintf (dump_file,
": %s %sobject size "
HOST_WIDE_INT_PRINT_UNSIGNED "\n",
(object_size_type & 2) ? "minimum" : "maximum",
(object_size_type & 1) ? "sub" : "",
object_sizes[object_size_type][i]);
}
}
BITMAP_FREE (osi.reexamine);
BITMAP_FREE (osi.visited);
}
bool
compute_builtin_object_size (tree ptr, int object_size_type,
unsigned HOST_WIDE_INT *psize)
{
gcc_assert (object_size_type >= 0 && object_size_type <= 3);
/* Set to unknown and overwrite just before returning if the size
could be determined. */
*psize = unknown[object_size_type];
if (! offset_limit)
init_offset_limit ();
if (TREE_CODE (ptr) == ADDR_EXPR)
return addr_object_size (NULL, ptr, object_size_type, psize);
if (TREE_CODE (ptr) != SSA_NAME
|| !POINTER_TYPE_P (TREE_TYPE (ptr)))
return false;
if (computed[object_size_type] == NULL)
{
if (optimize || object_size_type & 1)
return false;
/* When not optimizing, rather than failing, make a small effort
to determine the object size without the full benefit of
the (costly) computation below. */
gimple *def = SSA_NAME_DEF_STMT (ptr);
if (gimple_code (def) == GIMPLE_ASSIGN)
{
tree_code code = gimple_assign_rhs_code (def);
if (code == POINTER_PLUS_EXPR)
{
tree offset = gimple_assign_rhs2 (def);
ptr = gimple_assign_rhs1 (def);
if (tree_fits_shwi_p (offset)
&& compute_builtin_object_size (ptr, object_size_type, psize))
{
/* Return zero when the offset is out of bounds. */
unsigned HOST_WIDE_INT off = tree_to_shwi (offset);
*psize = off < *psize ? *psize - off : 0;
return true;
}
}
}
return false;
}
if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr)))
{
struct object_size_info osi;
bitmap_iterator bi;
unsigned int i;
if (num_ssa_names > object_sizes[object_size_type].length ())
object_sizes[object_size_type].safe_grow (num_ssa_names);
if (dump_file)
{
fprintf (dump_file, "Computing %s %sobject size for ",
(object_size_type & 2) ? "minimum" : "maximum",
(object_size_type & 1) ? "sub" : "");
print_generic_expr (dump_file, ptr, dump_flags);
fprintf (dump_file, ":\n");
}
osi.visited = BITMAP_ALLOC (NULL);
osi.reexamine = BITMAP_ALLOC (NULL);
osi.object_size_type = object_size_type;
osi.depths = NULL;
osi.stack = NULL;
osi.tos = NULL;
/* First pass: walk UD chains, compute object sizes that
can be computed. osi.reexamine bitmap at the end will
contain what variables were found in dependency cycles
and therefore need to be reexamined. */
osi.pass = 0;
osi.changed = false;
collect_object_sizes_for (&osi, ptr);
/* Second pass: keep recomputing object sizes of variables
that need reexamination, until no object sizes are
increased or all object sizes are computed. */
if (! bitmap_empty_p (osi.reexamine))
{
bitmap reexamine = BITMAP_ALLOC (NULL);
/* If looking for minimum instead of maximum object size,
detect cases where a pointer is increased in a loop.
Although even without this detection pass 2 would eventually
terminate, it could take a long time. If a pointer is
increasing this way, we need to assume 0 object size.
E.g. p = &buf[0]; while (cond) p = p + 4; */
if (object_size_type & 2)
{
osi.depths = XCNEWVEC (unsigned int, num_ssa_names);
osi.stack = XNEWVEC (unsigned int, num_ssa_names);
osi.tos = osi.stack;
osi.pass = 1;
/* collect_object_sizes_for is changing
osi.reexamine bitmap, so iterate over a copy. */
bitmap_copy (reexamine, osi.reexamine);
EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
if (bitmap_bit_p (osi.reexamine, i))
check_for_plus_in_loops (&osi, ssa_name (i));
free (osi.depths);
osi.depths = NULL;
free (osi.stack);
osi.stack = NULL;
osi.tos = NULL;
}
do
{
osi.pass = 2;
osi.changed = false;
/* collect_object_sizes_for is changing
osi.reexamine bitmap, so iterate over a copy. */
bitmap_copy (reexamine, osi.reexamine);
EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
if (bitmap_bit_p (osi.reexamine, i))
{
collect_object_sizes_for (&osi, ssa_name (i));
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Reexamining ");
print_generic_expr (dump_file, ssa_name (i),
dump_flags);
fprintf (dump_file, "\n");
}
}
}
while (osi.changed);
BITMAP_FREE (reexamine);
}
