1 /* Array bounds checking.
2 Copyright (C) 2005-2021 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
27 #include "gimple-array-bounds.h"
28 #include "gimple-iterator.h"
29 #include "gimple-walk.h"
31 #include "fold-const.h"
32 #include "diagnostic-core.h"
35 #include "alloc-pool.h"
36 #include "vr-values.h"
42 // This purposely returns a value_range, not a value_range_equiv, to
43 // break the dependency on equivalences for this pass.
46 array_bounds_checker::get_value_range (const_tree op
, gimple
*stmt
)
48 return ranges
->get_value_range (op
, stmt
);
51 /* Try to determine the DECL that REF refers to. Return the DECL or
52 the expression closest to it. Used in informational notes pointing
53 to referenced objects or function parameters. */
56 get_base_decl (tree ref
)
58 tree base
= get_base_address (ref
);
62 if (TREE_CODE (base
) == MEM_REF
)
63 base
= TREE_OPERAND (base
, 0);
65 if (TREE_CODE (base
) != SSA_NAME
)
70 gimple
*def
= SSA_NAME_DEF_STMT (base
);
71 if (gimple_assign_single_p (def
))
73 base
= gimple_assign_rhs1 (def
);
74 if (TREE_CODE (base
) != ASSERT_EXPR
)
77 base
= TREE_OPERAND (base
, 0);
78 if (TREE_CODE (base
) != SSA_NAME
)
84 if (!gimple_nop_p (def
))
90 tree var
= SSA_NAME_VAR (base
);
91 if (TREE_CODE (var
) != PARM_DECL
)
97 /* Return the constant byte size of the object or type referenced by
98 the MEM_REF ARG. On success, set *PREF to the DECL or expression
99 ARG refers to. Otherwise return null. */
102 get_ref_size (tree arg
, tree
*pref
)
104 if (TREE_CODE (arg
) != MEM_REF
)
107 arg
= TREE_OPERAND (arg
, 0);
108 tree type
= TREE_TYPE (arg
);
109 if (!POINTER_TYPE_P (type
))
112 type
= TREE_TYPE (type
);
113 if (TREE_CODE (type
) != ARRAY_TYPE
)
116 tree nbytes
= TYPE_SIZE_UNIT (type
);
117 if (!nbytes
|| TREE_CODE (nbytes
) != INTEGER_CST
)
120 *pref
= get_base_decl (arg
);
124 /* Return true if REF is (likely) an ARRAY_REF to a trailing array member
125 of a struct. It refines array_at_struct_end_p by detecting a pointer
126 to an array and an array parameter declared using the [N] syntax (as
127 opposed to a pointer) and returning false. Set *PREF to the decl or
128 expression REF refers to. */
131 trailing_array (tree arg
, tree
*pref
)
134 tree base
= get_base_decl (arg
);
135 while (TREE_CODE (ref
) == ARRAY_REF
|| TREE_CODE (ref
) == MEM_REF
)
136 ref
= TREE_OPERAND (ref
, 0);
138 if (TREE_CODE (ref
) == COMPONENT_REF
)
140 *pref
= TREE_OPERAND (ref
, 1);
141 tree type
= TREE_TYPE (*pref
);
142 if (TREE_CODE (type
) == ARRAY_TYPE
)
144 /* A multidimensional trailing array is not considered special
145 no matter what its major bound is. */
146 type
= TREE_TYPE (type
);
147 if (TREE_CODE (type
) == ARRAY_TYPE
)
154 tree basetype
= TREE_TYPE (base
);
155 if (TREE_CODE (base
) == PARM_DECL
156 && POINTER_TYPE_P (basetype
))
158 tree ptype
= TREE_TYPE (basetype
);
159 if (TREE_CODE (ptype
) == ARRAY_TYPE
)
163 return array_at_struct_end_p (arg
);
166 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible
167 arrays and "struct" hacks. If VRP can determine that the array
168 subscript is a constant, check if it is outside valid range. If
169 the array subscript is a RANGE, warn if it is non-overlapping with
170 valid range. IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside
171 a ADDR_EXPR. Return true if a warning has been issued or if
172 no-warning is set. */
175 array_bounds_checker::check_array_ref (location_t location
, tree ref
,
176 gimple
*stmt
, bool ignore_off_by_one
)
178 if (warning_suppressed_p (ref
, OPT_Warray_bounds
))
179 /* Return true to have the caller prevent warnings for enclosing
183 tree low_sub
= TREE_OPERAND (ref
, 1);
184 tree up_sub
= low_sub
;
185 tree up_bound
= array_ref_up_bound (ref
);
187 /* Referenced decl if one can be determined. */
188 tree decl
= NULL_TREE
;
190 /* Set for accesses to interior zero-length arrays. */
191 special_array_member sam
{ };
196 || TREE_CODE (up_bound
) != INTEGER_CST
197 || (warn_array_bounds
< 2 && trailing_array (ref
, &decl
)))
199 /* Accesses to trailing arrays via pointers may access storage
200 beyond the types array bounds. For such arrays, or for flexible
201 array members, as well as for other arrays of an unknown size,
202 replace the upper bound with a more permissive one that assumes
203 the size of the largest object is PTRDIFF_MAX. */
204 tree eltsize
= array_ref_element_size (ref
);
206 if (TREE_CODE (eltsize
) != INTEGER_CST
207 || integer_zerop (eltsize
))
209 up_bound
= NULL_TREE
;
210 up_bound_p1
= NULL_TREE
;
214 tree ptrdiff_max
= TYPE_MAX_VALUE (ptrdiff_type_node
);
215 tree maxbound
= ptrdiff_max
;
216 tree arg
= TREE_OPERAND (ref
, 0);
218 const bool compref
= TREE_CODE (arg
) == COMPONENT_REF
;
221 /* Try to determine the size of the trailing array from
222 its initializer (if it has one). */
223 if (tree refsize
= component_ref_size (arg
, &sam
))
224 if (TREE_CODE (refsize
) == INTEGER_CST
)
228 if (maxbound
== ptrdiff_max
)
230 /* Try to determine the size of the base object. Avoid
231 COMPONENT_REF already tried above. Using its DECL_SIZE
232 size wouldn't necessarily be correct if the reference is
233 to its flexible array member initialized in a different
236 if (tree base
= get_addr_base_and_unit_offset (arg
, &off
))
238 if (TREE_CODE (base
) == MEM_REF
)
240 /* Try to determine the size from a pointer to
241 an array if BASE is one. */
242 if (tree size
= get_ref_size (base
, &decl
))
245 else if (!compref
&& DECL_P (base
))
246 if (tree basesize
= DECL_SIZE_UNIT (base
))
247 if (TREE_CODE (basesize
) == INTEGER_CST
)
253 if (known_gt (off
, 0))
254 maxbound
= wide_int_to_tree (sizetype
,
255 wi::sub (wi::to_wide (maxbound
),
260 maxbound
= fold_convert (sizetype
, maxbound
);
262 up_bound_p1
= int_const_binop (TRUNC_DIV_EXPR
, maxbound
, eltsize
);
264 if (up_bound_p1
!= NULL_TREE
)
265 up_bound
= int_const_binop (MINUS_EXPR
, up_bound_p1
,
266 build_int_cst (ptrdiff_type_node
, 1));
268 up_bound
= NULL_TREE
;
272 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
,
273 build_int_cst (TREE_TYPE (up_bound
), 1));
275 tree low_bound
= array_ref_low_bound (ref
);
277 tree artype
= TREE_TYPE (TREE_OPERAND (ref
, 0));
282 if (up_bound
&& tree_int_cst_equal (low_bound
, up_bound_p1
))
283 warned
= warning_at (location
, OPT_Warray_bounds
,
284 "array subscript %E is outside array bounds of %qT",
287 const value_range
*vr
= NULL
;
288 if (TREE_CODE (low_sub
) == SSA_NAME
)
290 vr
= get_value_range (low_sub
, stmt
);
291 if (!vr
->undefined_p () && !vr
->varying_p ())
293 low_sub
= vr
->kind () == VR_RANGE
? vr
->max () : vr
->min ();
294 up_sub
= vr
->kind () == VR_RANGE
? vr
->min () : vr
->max ();
300 else if (vr
&& vr
->kind () == VR_ANTI_RANGE
)
303 && TREE_CODE (up_sub
) == INTEGER_CST
304 && (ignore_off_by_one
305 ? tree_int_cst_lt (up_bound
, up_sub
)
306 : tree_int_cst_le (up_bound
, up_sub
))
307 && TREE_CODE (low_sub
) == INTEGER_CST
308 && tree_int_cst_le (low_sub
, low_bound
))
309 warned
= warning_at (location
, OPT_Warray_bounds
,
310 "array subscript [%E, %E] is outside "
311 "array bounds of %qT",
312 low_sub
, up_sub
, artype
);
315 && TREE_CODE (up_sub
) == INTEGER_CST
316 && (ignore_off_by_one
317 ? !tree_int_cst_le (up_sub
, up_bound_p1
)
318 : !tree_int_cst_le (up_sub
, up_bound
)))
319 warned
= warning_at (location
, OPT_Warray_bounds
,
320 "array subscript %E is above array bounds of %qT",
322 else if (TREE_CODE (low_sub
) == INTEGER_CST
323 && tree_int_cst_lt (low_sub
, low_bound
))
324 warned
= warning_at (location
, OPT_Warray_bounds
,
325 "array subscript %E is below array bounds of %qT",
328 if (!warned
&& sam
== special_array_member::int_0
)
329 warned
= warning_at (location
, OPT_Wzero_length_bounds
,
330 (TREE_CODE (low_sub
) == INTEGER_CST
331 ? G_("array subscript %E is outside the bounds "
332 "of an interior zero-length array %qT")
333 : G_("array subscript %qE is outside the bounds "
334 "of an interior zero-length array %qT")),
339 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
341 fprintf (dump_file
, "Array bound warning for ");
342 dump_generic_expr (MSG_NOTE
, TDF_SLIM
, ref
);
343 fprintf (dump_file
, "\n");
346 /* Avoid more warnings when checking more significant subscripts
347 of the same expression. */
348 ref
= TREE_OPERAND (ref
, 0);
349 suppress_warning (ref
, OPT_Warray_bounds
);
354 tree rec
= NULL_TREE
;
355 if (TREE_CODE (ref
) == COMPONENT_REF
)
357 /* For a reference to a member of a struct object also mention
358 the object if it's known. It may be defined in a different
359 function than the out-of-bounds access. */
360 rec
= TREE_OPERAND (ref
, 0);
363 ref
= TREE_OPERAND (ref
, 1);
367 inform (DECL_SOURCE_LOCATION (ref
), "while referencing %qD", ref
);
368 if (rec
&& DECL_P (rec
))
369 inform (DECL_SOURCE_LOCATION (rec
), "defined here %qD", rec
);
375 /* Wrapper around build_array_type_nelts that makes sure the array
376 can be created at all and handles zero sized arrays specially. */
379 build_printable_array_type (tree eltype
, unsigned HOST_WIDE_INT nelts
)
381 if (TYPE_SIZE_UNIT (eltype
)
382 && TREE_CODE (TYPE_SIZE_UNIT (eltype
)) == INTEGER_CST
383 && !integer_zerop (TYPE_SIZE_UNIT (eltype
))
384 && TYPE_ALIGN_UNIT (eltype
) > 1
385 && wi::zext (wi::to_wide (TYPE_SIZE_UNIT (eltype
)),
386 ffs_hwi (TYPE_ALIGN_UNIT (eltype
)) - 1) != 0)
387 eltype
= TYPE_MAIN_VARIANT (eltype
);
390 return build_array_type_nelts (eltype
, nelts
);
392 tree idxtype
= build_range_type (sizetype
, size_zero_node
, NULL_TREE
);
393 tree arrtype
= build_array_type (eltype
, idxtype
);
394 arrtype
= build_distinct_type_copy (TYPE_MAIN_VARIANT (arrtype
));
395 TYPE_SIZE (arrtype
) = bitsize_zero_node
;
396 TYPE_SIZE_UNIT (arrtype
) = size_zero_node
;
400 /* Checks one MEM_REF in REF, located at LOCATION, for out-of-bounds
401 references to string constants. If VRP can determine that the array
402 subscript is a constant, check if it is outside valid range.
403 If the array subscript is a RANGE, warn if it is non-overlapping
405 IGNORE_OFF_BY_ONE is true if the MEM_REF is inside an ADDR_EXPR
406 (used to allow one-past-the-end indices for code that takes
407 the address of the just-past-the-end element of an array).
408 Returns true if a warning has been issued. */
411 array_bounds_checker::check_mem_ref (location_t location
, tree ref
,
412 bool ignore_off_by_one
)
414 if (warning_suppressed_p (ref
, OPT_Warray_bounds
))
417 /* The statement used to allocate the array or null. */
418 gimple
*alloc_stmt
= NULL
;
419 /* For an allocation statement, the low bound of the size range. */
420 offset_int minbound
= 0;
421 /* The type and size of the access. */
422 tree axstype
= TREE_TYPE (ref
);
423 offset_int axssize
= 0;
424 if (TREE_CODE (axstype
) != UNION_TYPE
)
425 if (tree access_size
= TYPE_SIZE_UNIT (axstype
))
426 if (TREE_CODE (access_size
) == INTEGER_CST
)
427 axssize
= wi::to_offset (access_size
);
430 if (!compute_objsize (ref
, 0, &aref
, ranges
))
433 if (aref
.offset_in_range (axssize
))
436 if (TREE_CODE (aref
.ref
) == SSA_NAME
)
438 gimple
*def
= SSA_NAME_DEF_STMT (aref
.ref
);
439 if (is_gimple_call (def
))
441 /* Save the allocation call and the low bound on the size. */
443 minbound
= aref
.sizrng
[0];
447 /* The range of the byte offset into the reference. Adjusted below. */
448 offset_int offrange
[2] = { aref
.offrng
[0], aref
.offrng
[1] };
450 /* The type of the referenced object. */
451 tree reftype
= TREE_TYPE (aref
.ref
);
452 /* The size of the referenced array element. */
453 offset_int eltsize
= 1;
454 /* The byte size of the array has already been determined above
455 based on a pointer ARG. Set ELTSIZE to the size of the type
456 it points to and REFTYPE to the array with the size, rounded
457 down as necessary. */
458 if (POINTER_TYPE_P (reftype
))
459 reftype
= TREE_TYPE (reftype
);
460 if (TREE_CODE (reftype
) == ARRAY_TYPE
)
461 reftype
= TREE_TYPE (reftype
);
462 if (tree refsize
= TYPE_SIZE_UNIT (reftype
))
463 if (TREE_CODE (refsize
) == INTEGER_CST
)
464 eltsize
= wi::to_offset (refsize
);
466 const offset_int nelts
= aref
.sizrng
[1] / eltsize
;
467 reftype
= build_printable_array_type (reftype
, nelts
.to_uhwi ());
469 /* Compute the more permissive upper bound when IGNORE_OFF_BY_ONE
470 is set (when taking the address of the one-past-last element
471 of an array) but always use the stricter bound in diagnostics. */
472 offset_int ubound
= aref
.sizrng
[1];
473 if (ignore_off_by_one
)
476 /* Set if the lower bound of the subscript is out of bounds. */
477 const bool lboob
= (aref
.sizrng
[1] == 0
478 || offrange
[0] >= ubound
480 /* Set if only the upper bound of the subscript is out of bounds.
481 This can happen when using a bigger type to index into an array
482 of a smaller type, as is common with unsigned char. */
483 const bool uboob
= !lboob
&& offrange
[0] + axssize
> ubound
;
486 /* Treat a reference to a non-array object as one to an array
487 of a single element. */
488 if (TREE_CODE (reftype
) != ARRAY_TYPE
)
489 reftype
= build_printable_array_type (reftype
, 1);
491 /* Extract the element type out of MEM_REF and use its size
492 to compute the index to print in the diagnostic; arrays
493 in MEM_REF don't mean anything. A type with no size like
494 void is as good as having a size of 1. */
495 tree type
= strip_array_types (TREE_TYPE (ref
));
496 if (tree size
= TYPE_SIZE_UNIT (type
))
498 offrange
[0] = offrange
[0] / wi::to_offset (size
);
499 offrange
[1] = offrange
[1] / wi::to_offset (size
);
506 if (offrange
[0] == offrange
[1])
507 warned
= warning_at (location
, OPT_Warray_bounds
,
508 "array subscript %wi is outside array bounds "
510 offrange
[0].to_shwi (), reftype
);
512 warned
= warning_at (location
, OPT_Warray_bounds
,
513 "array subscript [%wi, %wi] is outside "
514 "array bounds of %qT",
515 offrange
[0].to_shwi (),
516 offrange
[1].to_shwi (), reftype
);
518 else if (uboob
&& !ignore_off_by_one
)
520 tree backtype
= reftype
;
522 /* If the memory was dynamically allocated refer to it as if
523 it were an untyped array of bytes. */
524 backtype
= build_array_type_nelts (unsigned_char_type_node
,
525 aref
.sizrng
[1].to_uhwi ());
527 warned
= warning_at (location
, OPT_Warray_bounds
,
528 "array subscript %<%T[%wi]%> is partly "
529 "outside array bounds of %qT",
530 axstype
, offrange
[0].to_shwi (), backtype
);
535 /* TODO: Determine the access from the statement and use it. */
536 aref
.inform_access (access_none
);
537 suppress_warning (ref
, OPT_Warray_bounds
);
541 if (warn_array_bounds
< 2)
544 /* At level 2 check also intermediate offsets. */
546 if (aref
.offmax
[i
] < -aref
.sizrng
[1] || aref
.offmax
[i
= 1] > ubound
)
548 HOST_WIDE_INT tmpidx
= aref
.offmax
[i
].to_shwi () / eltsize
.to_shwi ();
550 if (warning_at (location
, OPT_Warray_bounds
,
551 "intermediate array offset %wi is outside array bounds "
552 "of %qT", tmpidx
, reftype
))
554 suppress_warning (ref
, OPT_Warray_bounds
);
562 /* Searches if the expr T, located at LOCATION computes
563 address of an ARRAY_REF, and call check_array_ref on it. */
566 array_bounds_checker::check_addr_expr (location_t location
, tree t
,
569 /* For the most significant subscript only, accept taking the address
570 of the just-past-the-end element. */
571 bool ignore_off_by_one
= true;
573 /* Check each ARRAY_REF and MEM_REF in the reference chain. */
577 if (TREE_CODE (t
) == ARRAY_REF
)
579 warned
= check_array_ref (location
, t
, stmt
, ignore_off_by_one
);
580 ignore_off_by_one
= false;
582 else if (TREE_CODE (t
) == MEM_REF
)
583 warned
= check_mem_ref (location
, t
, ignore_off_by_one
);
586 suppress_warning (t
, OPT_Warray_bounds
);
588 t
= TREE_OPERAND (t
, 0);
590 while (handled_component_p (t
) || TREE_CODE (t
) == MEM_REF
);
592 if (TREE_CODE (t
) != MEM_REF
593 || TREE_CODE (TREE_OPERAND (t
, 0)) != ADDR_EXPR
594 || warning_suppressed_p (t
, OPT_Warray_bounds
))
597 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
598 tree low_bound
, up_bound
, el_sz
;
599 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
600 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
601 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
604 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
605 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
606 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
608 || TREE_CODE (low_bound
) != INTEGER_CST
610 || TREE_CODE (up_bound
) != INTEGER_CST
612 || TREE_CODE (el_sz
) != INTEGER_CST
)
616 if (!mem_ref_offset (t
).is_constant (&idx
))
620 idx
= wi::sdiv_trunc (idx
, wi::to_offset (el_sz
));
623 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
625 fprintf (dump_file
, "Array bound warning for ");
626 dump_generic_expr (MSG_NOTE
, TDF_SLIM
, t
);
627 fprintf (dump_file
, "\n");
629 warned
= warning_at (location
, OPT_Warray_bounds
,
630 "array subscript %wi is below "
631 "array bounds of %qT",
632 idx
.to_shwi (), TREE_TYPE (tem
));
634 else if (idx
> (wi::to_offset (up_bound
)
635 - wi::to_offset (low_bound
) + 1))
637 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
639 fprintf (dump_file
, "Array bound warning for ");
640 dump_generic_expr (MSG_NOTE
, TDF_SLIM
, t
);
641 fprintf (dump_file
, "\n");
643 warned
= warning_at (location
, OPT_Warray_bounds
,
644 "array subscript %wu is above "
645 "array bounds of %qT",
646 idx
.to_uhwi (), TREE_TYPE (tem
));
652 inform (DECL_SOURCE_LOCATION (t
), "while referencing %qD", t
);
654 suppress_warning (t
, OPT_Warray_bounds
);
658 /* Return true if T is a reference to a member of a base class that's within
659 the bounds of the enclosing complete object. The function "hacks" around
660 problems discussed in pr98266 and pr97595. */
663 inbounds_memaccess_p (tree t
)
665 if (TREE_CODE (t
) != COMPONENT_REF
)
668 tree mref
= TREE_OPERAND (t
, 0);
669 if (TREE_CODE (mref
) != MEM_REF
)
672 /* Consider the access if its type is a derived class. */
673 tree mreftype
= TREE_TYPE (mref
);
674 if (!RECORD_OR_UNION_TYPE_P (mreftype
)
675 || !TYPE_BINFO (mreftype
))
678 /* Compute the size of the referenced object (it could be dynamically
680 access_ref aref
; // unused
681 tree refop
= TREE_OPERAND (mref
, 0);
682 tree refsize
= compute_objsize (refop
, 1, &aref
);
683 if (!refsize
|| TREE_CODE (refsize
) != INTEGER_CST
)
686 /* Compute the byte offset of the member within its enclosing class. */
687 tree fld
= TREE_OPERAND (t
, 1);
688 tree fldpos
= byte_position (fld
);
689 if (TREE_CODE (fldpos
) != INTEGER_CST
)
692 /* Compute the byte offset of the member with the outermost complete
693 object by adding its offset computed above to the MEM_REF offset. */
694 tree refoff
= TREE_OPERAND (mref
, 1);
695 tree fldoff
= int_const_binop (PLUS_EXPR
, fldpos
, refoff
);
696 /* Return false if the member offset is greater or equal to the size
697 of the complete object. */
698 if (!tree_int_cst_lt (fldoff
, refsize
))
701 tree fldsiz
= DECL_SIZE_UNIT (fld
);
702 if (!fldsiz
|| TREE_CODE (fldsiz
) != INTEGER_CST
)
705 /* Return true if the offset just past the end of the member is less
706 than or equal to the size of the complete object. */
707 tree fldend
= int_const_binop (PLUS_EXPR
, fldoff
, fldsiz
);
708 return tree_int_cst_le (fldend
, refsize
);
711 /* Callback for walk_tree to check a tree for out of bounds array
712 accesses. The array_bounds_checker class is passed in DATA. */
715 array_bounds_checker::check_array_bounds (tree
*tp
, int *walk_subtree
,
719 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
722 if (EXPR_HAS_LOCATION (t
))
723 location
= EXPR_LOCATION (t
);
725 location
= gimple_location (wi
->stmt
);
727 *walk_subtree
= TRUE
;
730 array_bounds_checker
*checker
= (array_bounds_checker
*) wi
->info
;
731 if (TREE_CODE (t
) == ARRAY_REF
)
732 warned
= checker
->check_array_ref (location
, t
, wi
->stmt
,
733 false/*ignore_off_by_one*/);
734 else if (TREE_CODE (t
) == MEM_REF
)
735 warned
= checker
->check_mem_ref (location
, t
,
736 false /*ignore_off_by_one*/);
737 else if (TREE_CODE (t
) == ADDR_EXPR
)
739 checker
->check_addr_expr (location
, t
, wi
->stmt
);
740 *walk_subtree
= false;
742 else if (inbounds_memaccess_p (t
))
743 /* Hack: Skip MEM_REF checks in accesses to a member of a base class
744 at an offset that's within the bounds of the enclosing object.
745 See pr98266 and pr97595. */
746 *walk_subtree
= false;
748 /* Propagate the no-warning bit to the outer statement to avoid also
749 issuing -Wstringop-overflow/-overread for the out-of-bounds accesses. */
751 suppress_warning (wi
->stmt
, OPT_Warray_bounds
);
756 /* A dom_walker subclass for use by check_all_array_refs, to walk over
757 all statements of all reachable BBs and call check_array_bounds on
760 class check_array_bounds_dom_walker
: public dom_walker
763 check_array_bounds_dom_walker (array_bounds_checker
*checker
)
764 : dom_walker (CDI_DOMINATORS
,
765 /* Discover non-executable edges, preserving EDGE_EXECUTABLE
766 flags, so that we can merge in information on
767 non-executable edges from vrp_folder . */
768 REACHABLE_BLOCKS_PRESERVING_FLAGS
),
769 checker (checker
) { }
770 ~check_array_bounds_dom_walker () {}
772 edge
before_dom_children (basic_block
) FINAL OVERRIDE
;
775 array_bounds_checker
*checker
;
778 /* Implementation of dom_walker::before_dom_children.
780 Walk over all statements of BB and call check_array_bounds on them,
781 and determine if there's a unique successor edge. */
784 check_array_bounds_dom_walker::before_dom_children (basic_block bb
)
786 gimple_stmt_iterator si
;
787 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
789 gimple
*stmt
= gsi_stmt (si
);
790 struct walk_stmt_info wi
;
791 if (!gimple_has_location (stmt
)
792 || is_gimple_debug (stmt
))
795 memset (&wi
, 0, sizeof (wi
));
799 walk_gimple_op (stmt
, array_bounds_checker::check_array_bounds
, &wi
);
802 /* Determine if there's a unique successor edge, and if so, return
803 that back to dom_walker, ensuring that we don't visit blocks that
804 became unreachable during the VRP propagation
805 (PR tree-optimization/83312). */
806 return find_taken_edge (bb
, NULL_TREE
);
810 array_bounds_checker::check ()
812 check_array_bounds_dom_walker
w (this);
813 w
.walk (ENTRY_BLOCK_PTR_FOR_FN (fun
));