if (TREE_CODE (idx) != INTEGER_CST
&& TREE_CODE (argtype) == POINTER_TYPE)
{
/* From a pointer (but not array) argument extract the variable
index to prevent get_addr_base_and_unit_offset() from failing
due to it. Use it later to compute the non-constant offset
into the string and return it to the caller. */
varidx = idx;
ref = TREE_OPERAND (arg, 0);
tree type = TREE_TYPE (arg);
if (TREE_CODE (type) == ARRAY_TYPE
&& TREE_CODE (type) != INTEGER_TYPE)
return NULL_TREE;
}
the condition TREE_CODE(type) == ARRAY_TYPE
&& TREE_CODE (type) != INTEGER_TYPE looks funny.
Check for ARRAY_TYPE should imply != INTEGER_TYPE.
else if (DECL_P (arg))
{
array = arg;
chartype = TREE_TYPE (arg);
}
chartype is only used in the if (varidx) block, but that is always zero
in this case.
while (TREE_CODE (chartype) == ARRAY_TYPE
|| TREE_CODE (chartype) == POINTER_TYPE)
chartype = TREE_TYPE (chartype);
you multiply sizeof(chartype) with varidx but you should probably
use the type of the TREE_OPERAND (arg, 0); above instead.
this is not in the patch, but I dont like it at all, because it compares the
size of a single initializer against the full size of the array. But it should
be the innermost enclosing array:
tree array_size = DECL_SIZE_UNIT (array);
if (!array_size || TREE_CODE (array_size) != INTEGER_CST)
return NULL_TREE;
/* Avoid returning a string that doesn't fit in the array
it is stored in, like
const char a[4] = "abcde";
but do handle those that fit even if they have excess
initializers, such as in
const char a[4] = "abc\000\000";
The excess elements contribute to TREE_STRING_LENGTH()
but not to strlen(). */
unsigned HOST_WIDE_INT length
= strnlen (TREE_STRING_POINTER (init), TREE_STRING_LENGTH (init));
if (compare_tree_int (array_size, length + 1) < 0)
return NULL_TREE;
consider the following test case:
$ cat part.c
const char a[2][3][8] = { { "a", "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb", "ccc"},
{ "dddd", "eeeee", "ffffff" } };
int main ()
{
int n = __builtin_strlen (&a[0][1][0]);
if (n == 30)
__builtin_abort ();
}
11413 if (!init || TREE_CODE (init) != STRING_CST)
(gdb) call debug(init)
"bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
(gdb) n
11416 tree array_size = DECL_SIZE_UNIT (array);
(gdb) n
11417 if (!array_size || TREE_CODE (array_size) != INTEGER_CST)
(gdb) call debug(array_size)
48
(gdb) n
11429 = strnlen (TREE_STRING_POINTER (init), TREE_STRING_LENGTH (init));
(gdb) n
11430 if (compare_tree_int (array_size, length + 1) < 0)
(gdb) n
11433 *ptr_offset = offset;
(gdb)
Bernd.
