git
/
gcc
mirror of git://gcc.gnu.org/git/gcc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

re PR middle-end/32135 (bogus array-ref fold triggering array overflow warning) 

PR middle-end/32135
	* tree-ssa-ccp.c (maybe_fold_offset_to_array_ref): Do not construct
	references above array bounds.  This might trigger bounds checks for
	pointers to arrays.

From-SVN: r131502
This commit is contained in:
Jan Hubicka 2008-01-13 12:18:08 +01:00 committed by Jan Hubicka
parent 42b22da884
commit 3097760b30
4 changed files with 45 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
2008-01-12 Jan Hubicka <jh@suse.cz>
PR middle-end/32135
* tree-ssa-ccp.c (maybe_fold_offset_to_array_ref): Do not construct
references above array bounds. This might trigger bounds checks for
pointers to arrays.
2008-01-12 Sebastian Pop <sebastian.pop@amd.com>
* tree-ssa-ter.c (free_temp_expr_table): Free num_in_part and

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2008-01-13 Jan Hubicka <jh@suse.cz>
PR middle-end/32135
* gcc.dg/pr32135.c: new.
2008-01-12 Doug Kwan <dougkwan@google.com>
* gcc.dg/qual-return-1.c: Add -Wignored-qualifiers.

11
gcc/testsuite/gcc.dg/pr32135.c Normal file
View File

@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-Warray-bounds -O2" } */
struct PhaseEntryType
{
char raw_field[50 + 1];
};
int
ParsePhase (char in_cols[15][250], struct PhaseEntryType *P)
{
__builtin_strncpy (P->raw_field, in_cols[2], 50);
}

24
gcc/tree-ssa-ccp.c
View File

@ -1588,6 +1588,7 @@ maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type)
{
tree min_idx, idx, idx_type, elt_offset = integer_zero_node;
tree array_type, elt_type, elt_size;
tree domain_type;
/* If BASE is an ARRAY_REF, we can pick up another offset (this time
measured in units of the size of elements type) from that ARRAY_REF).
@ -1659,9 +1660,10 @@ maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type)
low bound, if any, convert the index into that type, and add the
low bound. */
min_idx = build_int_cst (idx_type, 0);
if (TYPE_DOMAIN (array_type))
domain_type = TYPE_DOMAIN (array_type);
if (domain_type)
{
idx_type = TYPE_DOMAIN (array_type);
idx_type = domain_type;
if (TYPE_MIN_VALUE (idx_type))
min_idx = TYPE_MIN_VALUE (idx_type);
else
@ -1681,6 +1683,24 @@ maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type)
/* Make sure to possibly truncate late after offsetting. */
idx = fold_convert (idx_type, idx);
/* We don't want to construct access past array bounds. For example
char *(c[4]);
c[3][2]; should not be simplified into (*c)[14] or tree-vrp will give false
warning. */
if (domain_type && TYPE_MAX_VALUE (domain_type)
&& TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST)
{
tree up_bound = TYPE_MAX_VALUE (domain_type);
if (tree_int_cst_lt (up_bound, idx)
/* Accesses after the end of arrays of size 0 (gcc
extension) and 1 are likely intentional ("struct
hack"). */
&& compare_tree_int (up_bound, 1) > 0)
return NULL_TREE;
}
return build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
}