This fixes __builtin_object_size folding on static storage accessed
via a type with a trailing array element.
Bootstrapped and tested on x86_64-unknown-linux-gnu, will apply
after testing on the 4.6 branch.
Thanks,
Richard.
2011-10-12 Richard Guenther <rguent...@suse.de>
PR tree-optimization/50700
* tree-object-size.c (addr_object_size): Simplify and treat
MEM_REF bases consistently.
* gcc.dg/builtin-object-size-12.c: New testcase.
Index: gcc/tree-object-size.c
===================================================================
*** gcc/tree-object-size.c (revision 179757)
--- gcc/tree-object-size.c (working copy)
*************** addr_object_size (struct object_size_inf
*** 166,189 ****
gcc_assert (TREE_CODE (ptr) == ADDR_EXPR);
pt_var = TREE_OPERAND (ptr, 0);
! if (REFERENCE_CLASS_P (pt_var))
! pt_var = get_base_address (pt_var);
if (pt_var
! && TREE_CODE (pt_var) == MEM_REF
! && TREE_CODE (TREE_OPERAND (pt_var, 0)) == SSA_NAME
! && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (pt_var, 0))))
{
unsigned HOST_WIDE_INT sz;
! if (!osi || (object_size_type & 1) != 0)
{
sz = compute_builtin_object_size (TREE_OPERAND (pt_var, 0),
object_size_type & ~1);
- if (host_integerp (TREE_OPERAND (pt_var, 1), 0))
- sz -= TREE_INT_CST_LOW (TREE_OPERAND (pt_var, 1));
- else
- sz = offset_limit;
}
else
{
--- 166,184 ----
gcc_assert (TREE_CODE (ptr) == ADDR_EXPR);
pt_var = TREE_OPERAND (ptr, 0);
! while (handled_component_p (pt_var))
! pt_var = TREE_OPERAND (pt_var, 0);
if (pt_var
! && TREE_CODE (pt_var) == MEM_REF)
{
unsigned HOST_WIDE_INT sz;
! if (!osi || (object_size_type & 1) != 0
! || TREE_CODE (pt_var) != SSA_NAME)
{
sz = compute_builtin_object_size (TREE_OPERAND (pt_var, 0),
object_size_type & ~1);
}
else
{
*************** addr_object_size (struct object_size_inf
*** 195,204 ****
sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)];
else
sz = unknown[object_size_type];
! if (host_integerp (TREE_OPERAND (pt_var, 1), 0))
! sz -= TREE_INT_CST_LOW (TREE_OPERAND (pt_var, 1));
else
! sz = offset_limit;
}
if (sz != unknown[object_size_type] && sz < offset_limit)
--- 190,206 ----
sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)];
else
sz = unknown[object_size_type];
! }
! if (sz != unknown[object_size_type])
! {
! double_int dsz = double_int_sub (uhwi_to_double_int (sz),
! mem_ref_offset (pt_var));
! if (double_int_negative_p (dsz))
! sz = 0;
! else if (double_int_fits_in_uhwi_p (dsz))
! sz = double_int_to_uhwi (dsz);
else
! sz = unknown[object_size_type];
}
if (sz != unknown[object_size_type] && sz < offset_limit)
*************** addr_object_size (struct object_size_inf
*** 211,217 ****
tree_low_cst (DECL_SIZE_UNIT (pt_var), 1) < offset_limit)
pt_var_size = DECL_SIZE_UNIT (pt_var);
else if (pt_var
! && (SSA_VAR_P (pt_var) || TREE_CODE (pt_var) == STRING_CST)
&& TYPE_SIZE_UNIT (TREE_TYPE (pt_var))
&& host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1)
&& (unsigned HOST_WIDE_INT)
--- 213,219 ----
tree_low_cst (DECL_SIZE_UNIT (pt_var), 1) < offset_limit)
pt_var_size = DECL_SIZE_UNIT (pt_var);
else if (pt_var
! && TREE_CODE (pt_var) == STRING_CST
&& TYPE_SIZE_UNIT (TREE_TYPE (pt_var))
&& host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1)
&& (unsigned HOST_WIDE_INT)
Index: gcc/testsuite/gcc.dg/builtin-object-size-12.c
===================================================================
*** gcc/testsuite/gcc.dg/builtin-object-size-12.c (revision 0)
--- gcc/testsuite/gcc.dg/builtin-object-size-12.c (revision 0)
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-do run } */
+ /* { dg-options "-O2" } */
+
+ extern void abort (void);
+ struct S {
+ int len;
+ char s[0];
+ };
+ int main()
+ {
+ char buf[sizeof (struct S) + 32];
+ if (__builtin_object_size (((struct S *)&buf[0])->s, 1) != 32)
+ abort ();
+ if (__builtin_object_size (((struct S *)&buf[1])->s, 1) != 31)
+ abort ();
+ if (__builtin_object_size (((struct S *)&buf[64])->s, 0) != 0)
+ abort ();
+ return 0;
+ }
