PR middle-end/92815 - spurious -Wstringop-overflow writing into a flexible array of an extern struct
gcc/ChangeLog:
PR middle-end/92815
* tree-object-size.c (decl_init_size): New function.
(addr_object_size): Call it.
* tree.h (last_field): Declare.
(first_field): Add attribute nonnull.
gcc/testsuite/ChangeLog:
PR middle-end/92815
* gcc.dg/Warray-bounds-56.c: Remove xfails.
* gcc.dg/builtin-object-size-20.c: New test.
@@ -42,8 +42,8 @@ struct Flex f3 = { 3, { 1, 2, 3 } };
NOIPA void test_strcpy_flexarray (void)
{
- T (S (0), fx); // { dg-bogus "\\\[-Warray-bounds" "pr92815" { xfail *-*-*} }
- T (S (9), fx); // { dg-bogus "\\\[-Warray-bounds" "pr92815" { xfail *-*-*} }
+ T (S (0), fx); // { dg-bogus "\\\[-Warray-bounds" "pr92815" }
+ T (S (9), fx); // { dg-bogus "\\\[-Warray-bounds" "pr92815" }
T (S (0), f1);
T (S (1), f1); // { dg-warning "\\\[-Warray-bounds" }
new file mode 100644
@@ -0,0 +1,315 @@
+/* PR middle-end/92815 - spurious -Wstringop-overflow writing into
+ a flexible array of an extern struct
+ { dg-do compile }
+ { dg-options "-Wall -fdump-tree-optimized" } */
+
+#define ASSERT(expr) ((expr) ? (void)0 : fail (__LINE__))
+#define bos0(expr) __builtin_object_size (expr, 1)
+#define bos1(expr) __builtin_object_size (expr, 1)
+#define bos2(expr) __builtin_object_size (expr, 2)
+#define bos3(expr) __builtin_object_size (expr, 3)
+
+typedef __INT16_TYPE__ int16_t;
+typedef __INT32_TYPE__ int32_t;
+typedef __INT64_TYPE__ int64_t;
+typedef __SIZE_TYPE__ size_t;
+
+
+extern void fail (int);
+
+
+/* Verify sizes of a struct with a flexible array member and no padding. */
+
+struct ACX { char n, a[]; };
+
+struct ACX ac0 = { };
+struct ACX ac1 = { 1, { 1 } };
+struct ACX ac2 = { 2, { 1, 2 } };
+struct ACX ac3 = { 3, { 1, 2, 3 } };
+
+extern struct ACX eacx;
+
+void facx (void)
+{
+ ASSERT (bos0 (&ac0) == sizeof ac0);
+ ASSERT (bos0 (&ac1) == 2);
+ ASSERT (bos0 (&ac2) == 3);
+ ASSERT (bos0 (&ac3) == 4);
+ ASSERT (bos0 (&eacx) == (size_t)-1);
+
+ ASSERT (bos1 (&ac0) == sizeof ac0);
+ ASSERT (bos1 (&ac1) == 2);
+ ASSERT (bos1 (&ac2) == 3);
+ ASSERT (bos1 (&ac3) == 4);
+ ASSERT (bos1 (&eacx) == (size_t)-1);
+
+ ASSERT (bos2 (&ac0) == sizeof ac0);
+ ASSERT (bos2 (&ac1) == 2);
+ ASSERT (bos2 (&ac2) == 3);
+ ASSERT (bos2 (&ac3) == 4);
+ ASSERT (bos2 (&eacx) == sizeof eacx);
+
+ ASSERT (bos3 (&ac0) == sizeof ac0);
+ ASSERT (bos3 (&ac1) == 2);
+ ASSERT (bos3 (&ac2) == 3);
+ ASSERT (bos3 (&ac3) == 4);
+ ASSERT (bos3 (&eacx) == sizeof eacx);
+}
+
+
+
+/* Verify sizes of a struct with a flexible array member and 1 byte
+ of tail padding. */
+
+struct AI16CX { int16_t i; char n, a[]; };
+
+struct AI16CX ai16c0 = { 0 };
+struct AI16CX ai16c1 = { 0, 1, { 1 } };
+struct AI16CX ai16c2 = { 0, 2, { 1, 2 } };
+struct AI16CX ai16c3 = { 0, 3, { 1, 2, 3 } };
+struct AI16CX ai16c4 = { 0, 4, { 1, 2, 3, 4 } };
+struct AI16CX ai16c5 = { 0, 5, { 1, 2, 3, 4, 5 } };
+struct AI16CX ai16c6 = { 0, 6, { 1, 2, 3, 4, 5, 6 } };
+struct AI16CX ai16c7 = { 0, 7, { 1, 2, 3, 4, 5, 6, 7 } };
+struct AI16CX ai16c8 = { 0, 8, { 1, 2, 3, 4, 5, 6, 7, 8 } };
+
+extern struct AI16CX eai16cx;
+
+void fai16cx (void)
+{
+ ASSERT (bos0 (&ai16c0) == sizeof ai16c0);
+ ASSERT (bos0 (&ai16c1) == sizeof ai16c1);
+ ASSERT (bos0 (&ai16c2) == sizeof ai16c2 + 1);
+ ASSERT (bos0 (&ai16c3) == sizeof ai16c3 + 2);
+
+ ASSERT (bos0 (&ai16c4) == sizeof ai16c4 + 3);
+ ASSERT (bos0 (&ai16c5) == sizeof ai16c5 + 4);
+ ASSERT (bos0 (&ai16c6) == sizeof ai16c6 + 5);
+ ASSERT (bos0 (&ai16c7) == sizeof ai16c6 + 6);
+ ASSERT (bos0 (&ai16c8) == sizeof ai16c6 + 7);
+
+ ASSERT (bos0 (&eai16cx) == (size_t)-1);
+
+
+ ASSERT (bos1 (&ai16c0) == sizeof ai16c0);
+ ASSERT (bos1 (&ai16c1) == sizeof ai16c1);
+ ASSERT (bos1 (&ai16c2) == sizeof ai16c2 + 1);
+ ASSERT (bos1 (&ai16c3) == sizeof ai16c3 + 2);
+
+ ASSERT (bos1 (&ai16c4) == sizeof ai16c4 + 3);
+ ASSERT (bos1 (&ai16c5) == sizeof ai16c5 + 4);
+ ASSERT (bos1 (&ai16c6) == sizeof ai16c6 + 5);
+ ASSERT (bos1 (&ai16c7) == sizeof ai16c6 + 6);
+ ASSERT (bos1 (&ai16c8) == sizeof ai16c6 + 7);
+
+ ASSERT (bos1 (&eai16cx) == (size_t)-1);
+
+
+ ASSERT (bos2 (&ai16c0) == sizeof ai16c0);
+ ASSERT (bos2 (&ai16c1) == sizeof ai16c1);
+ ASSERT (bos2 (&ai16c2) == sizeof ai16c2 + 1);
+ ASSERT (bos2 (&ai16c3) == sizeof ai16c3 + 2);
+
+ ASSERT (bos2 (&ai16c4) == sizeof ai16c4 + 3);
+ ASSERT (bos2 (&ai16c5) == sizeof ai16c5 + 4);
+ ASSERT (bos2 (&ai16c6) == sizeof ai16c6 + 5);
+ ASSERT (bos2 (&ai16c7) == sizeof ai16c6 + 6);
+ ASSERT (bos2 (&ai16c8) == sizeof ai16c6 + 7);
+
+ ASSERT (bos2 (&eai16cx) == sizeof eai16cx);
+
+
+ ASSERT (bos3 (&ai16c0) == sizeof ai16c0);
+ ASSERT (bos3 (&ai16c1) == sizeof ai16c1);
+ ASSERT (bos3 (&ai16c2) == sizeof ai16c2 + 1);
+ ASSERT (bos3 (&ai16c3) == sizeof ai16c3 + 2);
+
+ ASSERT (bos3 (&ai16c4) == sizeof ai16c4 + 3);
+ ASSERT (bos3 (&ai16c5) == sizeof ai16c5 + 4);
+ ASSERT (bos3 (&ai16c6) == sizeof ai16c6 + 5);
+ ASSERT (bos3 (&ai16c7) == sizeof ai16c6 + 6);
+ ASSERT (bos3 (&ai16c8) == sizeof ai16c6 + 7);
+
+ ASSERT (bos3 (&eai16cx) == sizeof eai16cx);
+}
+
+
+/* Verify sizes of a struct with a flexible array member and 3 bytes
+ of tail padding. */
+
+struct AI32CX { int32_t i; char n, a[]; };
+
+struct AI32CX ai32c0 = { 0 };
+struct AI32CX ai32c1 = { 0, 1, { 1 } };
+struct AI32CX ai32c2 = { 0, 2, { 1, 2 } };
+struct AI32CX ai32c3 = { 0, 3, { 1, 2, 3 } };
+struct AI32CX ai32c4 = { 0, 4, { 1, 2, 3, 4 } };
+struct AI32CX ai32c5 = { 0, 5, { 1, 2, 3, 4, 5 } };
+struct AI32CX ai32c6 = { 0, 6, { 1, 2, 3, 4, 5, 6 } };
+struct AI32CX ai32c7 = { 0, 7, { 1, 2, 3, 4, 5, 6, 7 } };
+struct AI32CX ai32c8 = { 0, 8, { 1, 2, 3, 4, 5, 6, 7, 8 } };
+
+extern struct AI32CX eai32cx;
+
+void fai32cx (void)
+{
+ ASSERT (bos0 (&ai32c0) == sizeof ai32c0);
+ ASSERT (bos0 (&ai32c1) == sizeof ai32c1);
+ ASSERT (bos0 (&ai32c2) == sizeof ai32c2);
+ ASSERT (bos0 (&ai32c3) == sizeof ai32c3);
+
+ ASSERT (bos0 (&ai32c4) == sizeof ai32c4 + 1);
+ ASSERT (bos0 (&ai32c5) == sizeof ai32c5 + 2);
+ ASSERT (bos0 (&ai32c6) == sizeof ai32c6 + 3);
+ ASSERT (bos0 (&ai32c7) == sizeof ai32c6 + 4);
+ ASSERT (bos0 (&ai32c8) == sizeof ai32c6 + 5);
+
+ ASSERT (bos0 (&eai32cx) == (size_t)-1);
+
+
+ ASSERT (bos1 (&ai32c0) == sizeof ai32c0);
+ ASSERT (bos1 (&ai32c1) == sizeof ai32c1);
+ ASSERT (bos1 (&ai32c2) == sizeof ai32c2);
+ ASSERT (bos1 (&ai32c3) == sizeof ai32c3);
+
+ ASSERT (bos1 (&ai32c4) == sizeof ai32c4 + 1);
+ ASSERT (bos1 (&ai32c5) == sizeof ai32c5 + 2);
+ ASSERT (bos1 (&ai32c6) == sizeof ai32c6 + 3);
+ ASSERT (bos1 (&ai32c7) == sizeof ai32c6 + 4);
+ ASSERT (bos1 (&ai32c8) == sizeof ai32c6 + 5);
+
+ ASSERT (bos1 (&eai32cx) == (size_t)-1);
+
+
+ ASSERT (bos2 (&ai32c0) == sizeof ai32c0);
+ ASSERT (bos2 (&ai32c1) == sizeof ai32c1);
+ ASSERT (bos2 (&ai32c2) == sizeof ai32c2);
+ ASSERT (bos2 (&ai32c3) == sizeof ai32c3);
+
+ ASSERT (bos2 (&ai32c4) == sizeof ai32c4 + 1);
+ ASSERT (bos2 (&ai32c5) == sizeof ai32c5 + 2);
+ ASSERT (bos2 (&ai32c6) == sizeof ai32c6 + 3);
+ ASSERT (bos2 (&ai32c7) == sizeof ai32c6 + 4);
+ ASSERT (bos2 (&ai32c8) == sizeof ai32c6 + 5);
+
+ ASSERT (bos2 (&eai32cx) == sizeof eai32cx);
+
+
+ ASSERT (bos3 (&ai32c0) == sizeof ai32c0);
+ ASSERT (bos3 (&ai32c1) == sizeof ai32c1);
+ ASSERT (bos3 (&ai32c2) == sizeof ai32c2);
+ ASSERT (bos3 (&ai32c3) == sizeof ai32c3);
+
+ ASSERT (bos3 (&ai32c4) == sizeof ai32c4 + 1);
+ ASSERT (bos3 (&ai32c5) == sizeof ai32c5 + 2);
+ ASSERT (bos3 (&ai32c6) == sizeof ai32c6 + 3);
+ ASSERT (bos3 (&ai32c7) == sizeof ai32c6 + 4);
+ ASSERT (bos3 (&ai32c8) == sizeof ai32c6 + 5);
+
+ ASSERT (bos3 (&eai32cx) == sizeof eai32cx);
+}
+
+
+/* Verify sizes of a struct with a flexible array member and 7 bytes
+ of tail padding. */
+
+struct AI64CX { int64_t i; char n, a[]; };
+
+struct AI64CX ai64c0 = { 0 };
+struct AI64CX ai64c1 = { 0, 1, { 1 } };
+struct AI64CX ai64c2 = { 0, 2, { 1, 2 } };
+struct AI64CX ai64c3 = { 0, 3, { 1, 2, 3 } };
+struct AI64CX ai64c4 = { 0, 4, { 1, 2, 3, 4 } };
+struct AI64CX ai64c5 = { 0, 5, { 1, 2, 3, 4, 5 } };
+struct AI64CX ai64c6 = { 0, 6, { 1, 2, 3, 4, 5, 6 } };
+struct AI64CX ai64c7 = { 0, 7, { 1, 2, 3, 4, 5, 6, 7 } };
+struct AI64CX ai64c8 = { 0, 8, { 1, 2, 3, 4, 5, 6, 7, 8 } };
+struct AI64CX ai64c9 = { 0, 8, { 1, 2, 3, 4, 5, 6, 7, 8, 9 } };
+
+extern struct AI64CX eai64cx;
+
+void fai64cx (void)
+{
+ ASSERT (bos0 (&ai64c0) == sizeof ai64c0);
+ ASSERT (bos0 (&ai64c1) == sizeof ai64c1);
+ ASSERT (bos0 (&ai64c2) == sizeof ai64c2);
+ ASSERT (bos0 (&ai64c3) == sizeof ai64c3);
+ ASSERT (bos0 (&ai64c4) == sizeof ai64c4);
+ ASSERT (bos0 (&ai64c5) == sizeof ai64c5);
+ ASSERT (bos0 (&ai64c6) == sizeof ai64c6);
+ ASSERT (bos0 (&ai64c7) == sizeof ai64c7);
+
+ ASSERT (bos0 (&ai64c8) == sizeof ai64c8 + 1);
+ ASSERT (bos0 (&ai64c9) == sizeof ai64c9 + 2);
+
+ ASSERT (bos0 (&eai64cx) == (size_t)-1);
+
+
+ ASSERT (bos1 (&ai64c0) == sizeof ai64c0);
+ ASSERT (bos1 (&ai64c1) == sizeof ai64c1);
+ ASSERT (bos1 (&ai64c2) == sizeof ai64c2);
+ ASSERT (bos1 (&ai64c3) == sizeof ai64c3);
+ ASSERT (bos1 (&ai64c4) == sizeof ai64c4);
+ ASSERT (bos1 (&ai64c5) == sizeof ai64c5);
+ ASSERT (bos1 (&ai64c6) == sizeof ai64c6);
+ ASSERT (bos1 (&ai64c7) == sizeof ai64c7);
+
+ ASSERT (bos1 (&ai64c8) == sizeof ai64c8 + 1);
+ ASSERT (bos1 (&ai64c9) == sizeof ai64c9 + 2);
+
+ ASSERT (bos1 (&eai64cx) == (size_t)-1);
+
+
+ ASSERT (bos2 (&ai64c0) == sizeof ai64c0);
+ ASSERT (bos2 (&ai64c1) == sizeof ai64c1);
+ ASSERT (bos2 (&ai64c2) == sizeof ai64c2);
+ ASSERT (bos2 (&ai64c3) == sizeof ai64c3);
+ ASSERT (bos2 (&ai64c4) == sizeof ai64c4);
+ ASSERT (bos2 (&ai64c5) == sizeof ai64c5);
+ ASSERT (bos2 (&ai64c6) == sizeof ai64c6);
+ ASSERT (bos2 (&ai64c7) == sizeof ai64c7);
+
+ ASSERT (bos2 (&ai64c8) == sizeof ai64c8 + 1);
+ ASSERT (bos2 (&ai64c9) == sizeof ai64c9 + 2);
+
+ ASSERT (bos2 (&eai64cx) == sizeof eai64cx);
+
+ ASSERT (bos3 (&ai64c0) == sizeof ai64c0);
+ ASSERT (bos3 (&ai64c1) == sizeof ai64c1);
+ ASSERT (bos3 (&ai64c2) == sizeof ai64c2);
+ ASSERT (bos3 (&ai64c3) == sizeof ai64c3);
+ ASSERT (bos3 (&ai64c4) == sizeof ai64c4);
+ ASSERT (bos3 (&ai64c5) == sizeof ai64c5);
+ ASSERT (bos3 (&ai64c6) == sizeof ai64c6);
+ ASSERT (bos3 (&ai64c7) == sizeof ai64c7);
+
+ ASSERT (bos3 (&ai64c8) == sizeof ai64c8 + 1);
+ ASSERT (bos3 (&ai64c9) == sizeof ai64c9 + 2);
+
+ ASSERT (bos3 (&eai64cx) == sizeof eai64cx);
+}
+
+
+/* Also verify sizes of a struct with a zero length array member. */
+
+struct A0C0 { char n, a[0]; };
+
+struct A0C0 a0c0 = { };
+extern struct A0C0 ea0c0;
+
+void fa0c0 (void)
+{
+ ASSERT (bos0 (&a0c0) == sizeof a0c0);
+ ASSERT (bos0 (&ea0c0) == sizeof ea0c0);
+
+ ASSERT (bos1 (&a0c0) == sizeof a0c0);
+ ASSERT (bos1 (&a0c0) == sizeof ea0c0);
+
+ ASSERT (bos2 (&a0c0) == sizeof a0c0);
+ ASSERT (bos2 (&a0c0) == sizeof ea0c0);
+
+ ASSERT (bos3 (&a0c0) == sizeof a0c0);
+ ASSERT (bos3 (&a0c0) == sizeof ea0c0);
+}
+
+/* { dg-final { scan-tree-dump-not "fail" "optimized" } } */
@@ -166,6 +166,42 @@ compute_object_offset (const_tree expr, const_tree var)
return size_binop (code, base, off);
}
+/* Returns the size of the object designated by DECL considering its
+ initializer if it either has one or if it would not affect its size,
+ otherwise the size of the object without the initializer when MIN
+ is true, else null. An object's initializer affects the object's
+ size if it's a struct type with a flexible array member. */
+
+static tree
+decl_init_size (tree decl, bool min)
+{
+ tree size = DECL_SIZE_UNIT (decl);
+ tree type = TREE_TYPE (decl);
+ if (TREE_CODE (type) != RECORD_TYPE)
+ return size;
+
+ tree last = last_field (type);
+ if (!last)
+ return size;
+
+ tree last_type = TREE_TYPE (last);
+ if (TREE_CODE (last_type) != ARRAY_TYPE
+ || TYPE_SIZE (last_type))
+ return size;
+
+ /* Use TYPE_SIZE_UNIT; DECL_SIZE_UNIT sometimes reflects the size
+ of the initializer and sometimes doesn't. */
+ size = TYPE_SIZE_UNIT (type);
+ tree ref = build3 (COMPONENT_REF, type, decl, last, NULL_TREE);
+ tree compsize = component_ref_size (ref);
+ if (!compsize)
+ return min ? size : NULL_TREE;
+
+ /* The size includes tail padding and initializer elements. */
+ tree pos = byte_position (last);
+ size = fold_build2 (PLUS_EXPR, TREE_TYPE (size), pos, compsize);
+ return size;
+}
/* Compute __builtin_object_size for PTR, which is a ADDR_EXPR.
OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
@@ -242,7 +278,7 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
&& tree_to_uhwi (DECL_SIZE_UNIT (pt_var)) < offset_limit)
{
*pdecl = pt_var;
- pt_var_size = DECL_SIZE_UNIT (pt_var);
+ pt_var_size = decl_init_size (pt_var, object_size_type & 2);
}
else if (pt_var
&& TREE_CODE (pt_var) == STRING_CST
@@ -4692,9 +4692,10 @@ extern tree nreverse (tree);
extern int list_length (const_tree);
-/* Returns the first FIELD_DECL in a type. */
+/* Returns the first/last FIELD_DECL in a RECORD_TYPE. */
-extern tree first_field (const_tree);
+extern tree first_field (const_tree) ATTRIBUTE_NONNULL (1);
+extern tree last_field (const_tree) ATTRIBUTE_NONNULL (1);
/* Given an initializer INIT, return TRUE if INIT is zero or some
aggregate of zeros. Otherwise return FALSE. If NONZERO is not