[v6,3/5] Use the .ACCESS_WITH_SIZE in builtin object size.
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Commit Message
gcc/ChangeLog:
* tree-object-size.cc (access_with_size_object_size): New function.
(call_object_size): Call the new function.
gcc/testsuite/ChangeLog:
* gcc.dg/builtin-object-size-common.h: Add a new macro EXPECT.
* gcc.dg/flex-array-counted-by-3.c: New test.
* gcc.dg/flex-array-counted-by-4.c: New test.
* gcc.dg/flex-array-counted-by-5.c: New test.
---
.../gcc.dg/builtin-object-size-common.h | 11 ++
.../gcc.dg/flex-array-counted-by-3.c | 63 +++++++
.../gcc.dg/flex-array-counted-by-4.c | 178 ++++++++++++++++++
.../gcc.dg/flex-array-counted-by-5.c | 48 +++++
gcc/tree-object-size.cc | 59 ++++++
5 files changed, 359 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
Comments
On 2024-02-16 14:47, Qing Zhao wrote:
> gcc/ChangeLog:
>
> * tree-object-size.cc (access_with_size_object_size): New function.
> (call_object_size): Call the new function.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/builtin-object-size-common.h: Add a new macro EXPECT.
> * gcc.dg/flex-array-counted-by-3.c: New test.
> * gcc.dg/flex-array-counted-by-4.c: New test.
> * gcc.dg/flex-array-counted-by-5.c: New test.
> ---
> .../gcc.dg/builtin-object-size-common.h | 11 ++
> .../gcc.dg/flex-array-counted-by-3.c | 63 +++++++
> .../gcc.dg/flex-array-counted-by-4.c | 178 ++++++++++++++++++
> .../gcc.dg/flex-array-counted-by-5.c | 48 +++++
> gcc/tree-object-size.cc | 59 ++++++
> 5 files changed, 359 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
> create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
> create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
>
> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-common.h b/gcc/testsuite/gcc.dg/builtin-object-size-common.h
> index 66ff7cdd953a..b677067c6e6b 100644
> --- a/gcc/testsuite/gcc.dg/builtin-object-size-common.h
> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-common.h
> @@ -30,3 +30,14 @@ unsigned nfails = 0;
> __builtin_abort (); \
> return 0; \
> } while (0)
> +
> +#define EXPECT(p, _v) do { \
> + size_t v = _v; \
> + if (p == v) \
> + __builtin_printf ("ok: %s == %zd\n", #p, p); \
> + else \
> + { \
> + __builtin_printf ("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
> + FAIL (); \
> + } \
> +} while (0);
> diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
> new file mode 100644
> index 000000000000..0066c32ca808
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
> @@ -0,0 +1,63 @@
> +/* test the attribute counted_by and its usage in
> + * __builtin_dynamic_object_size. */
> +/* { dg-do run } */
> +/* { dg-options "-O2" } */
> +
> +#include "builtin-object-size-common.h"
> +
> +struct flex {
> + int b;
> + int c[];
> +} *array_flex;
> +
> +struct annotated {
> + int b;
> + int c[] __attribute__ ((counted_by (b)));
> +} *array_annotated;
> +
> +struct nested_annotated {
> + struct {
> + union {
> + int b;
> + float f;
> + };
> + int n;
> + };
> + int c[] __attribute__ ((counted_by (b)));
> +} *array_nested_annotated;
> +
> +void __attribute__((__noinline__)) setup (int normal_count, int attr_count)
> +{
> + array_flex
> + = (struct flex *)malloc (sizeof (struct flex)
> + + normal_count * sizeof (int));
> + array_flex->b = normal_count;
> +
> + array_annotated
> + = (struct annotated *)malloc (sizeof (struct annotated)
> + + attr_count * sizeof (int));
> + array_annotated->b = attr_count;
> +
> + array_nested_annotated
> + = (struct nested_annotated *)malloc (sizeof (struct nested_annotated)
> + + attr_count * sizeof (int));
> + array_nested_annotated->b = attr_count;
> +
> + return;
> +}
> +
> +void __attribute__((__noinline__)) test ()
> +{
> + EXPECT(__builtin_dynamic_object_size(array_flex->c, 1), -1);
> + EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1),
> + array_annotated->b * sizeof (int));
> + EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1),
> + array_nested_annotated->b * sizeof (int));
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + setup (10,10);
> + test ();
> + DONE ();
> +}
> diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
> new file mode 100644
> index 000000000000..3ce7f3545549
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
> @@ -0,0 +1,178 @@
> +/* test the attribute counted_by and its usage in
> +__builtin_dynamic_object_size: what's the correct behavior when the
> +allocation size mismatched with the value of counted_by attribute?
> +we should always use the latest value that is hold by the counted_by
> +field. */
> +/* { dg-do run } */
> +/* { dg-options "-O -fstrict-flex-arrays=3" } */
> +
> +#include "builtin-object-size-common.h"
> +
> +struct annotated {
> + size_t foo;
> + char others;
> + char array[] __attribute__((counted_by (foo)));
> +};
> +
> +#define noinline __attribute__((__noinline__))
> +#define SIZE_BUMP 10
> +#define MAX(a, b) ((a) > (b) ? (a) : (b))
> +
> +/* In general, Due to type casting, the type for the pointee of a pointer
> + does not say anything about the object it points to,
> + So, __builtin_object_size can not directly use the type of the pointee
> + to decide the size of the object the pointer points to.
> +
> + there are only two reliable ways:
> + A. observed allocations (call to the allocation functions in the routine)
> + B. observed accesses (read or write access to the location of the
> + pointer points to)
> +
> + that provide information about the type/existence of an object at
> + the corresponding address.
> +
> + for A, we use the "alloc_size" attribute for the corresponding allocation
> + functions to determine the object size;
> + (We treat counted_by attribute the same as the "alloc_size" attribute)
> +
> + For B, we use the SIZE info of the TYPE attached to the corresponding access.
> +
> + The only other way in C which ensures that a pointer actually points
> + to an object of the correct type is 'static':
> +
> + void foo(struct P *p[static 1]);
> +
> + See https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624814.html
> + for more details. */
> +
> +/* in the following function, malloc allocated more space than the value
> + of counted_by attribute. Then what's the correct behavior we expect
> + the __builtin_dynamic_object_size should have for each of the cases? */
> +
> +static struct annotated * noinline alloc_buf_more (size_t index)
> +{
> + struct annotated *p;
> + size_t allocated_size
> + = MAX (sizeof (struct annotated),
> + (__builtin_offsetof (struct annotated, array[0])
> + + (index + SIZE_BUMP) * sizeof (char)));
> + p = (struct annotated *) malloc (allocated_size);
> +
> + p->foo = index;
> +
> + /*when checking the observed access p->array, we have info on both
> + observered allocation and observed access,
> + A.1 from observed allocation:
> + allocated_size - offsetof (struct annotated, array[0])
> +
> + A.2 from the counted-by attribute:
> + p->foo * sizeof (char)
> +
> + we always use the latest value that is hold by the counted-by field.
> + */
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 0),
> + (p->foo) * sizeof(char));
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 1),
> + (p->foo) * sizeof(char));
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 2),
> + (p->foo) * sizeof(char));
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 3),
> + (p->foo) * sizeof(char));
> +
> + /*when checking the pointer p, we only have info on the observed allocation.
> + So, the object size info can only been obtained from the call to malloc.
> + for both MAXIMUM and MINIMUM: A = (index + SIZE_BUMP) * sizeof (char) */
> + EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
> + EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
> + EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
> + EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
> + return p;
> +}
> +
> +/* in the following function, malloc allocated less space than the value
> + of counted_by attribute. Then what's the correct behavior we expect
> + the __builtin_dynamic_object_size should have for each of the cases?
> + NOTE: this is an user error, GCC should issue warnings for such case.
> + this is a seperate issue we should address later. */
> +
> +static struct annotated * noinline alloc_buf_less (size_t index)
> +{
> + struct annotated *p;
> + size_t allocated_size
> + = MAX (sizeof (struct annotated),
> + (__builtin_offsetof (struct annotated, array[0])
> + + (index) * sizeof (char)));
> + p = (struct annotated *) malloc (allocated_size);
> +
> + p->foo = index + SIZE_BUMP;
> +
> + /*when checking the observed access p->array, we have info on both
> + observered allocation and observed access,
> + A.1 from observed allocation:
> + allocated_size - offsetof (struct annotated, array[0])
> + A.2 from the counted-by attribute:
> + p->foo * sizeof (char)
> +
> + we always use the latest value that is hold by the counted-by field.
> + */
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 0),
> + (p->foo) * sizeof(char));
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 1),
> + (p->foo) * sizeof(char));
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 2),
> + (p->foo) * sizeof(char));
> +
> + EXPECT(__builtin_dynamic_object_size(p->array, 3),
> + (p->foo) * sizeof(char));
> +
> + /*when checking the pointer p, we only have info on the observed
> + allocation. So, the object size info can only been obtained from
> + the call to malloc. */
> + EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
> + EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
> + EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
> + EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
> + return p;
> +}
> +
> +int main ()
> +{
> + struct annotated *p, *q;
> + p = alloc_buf_more (10);
> + q = alloc_buf_less (10);
> +
> + /*when checking the access p->array, we only have info on the counted-by
> + value. */
> + EXPECT(__builtin_dynamic_object_size(p->array, 0), p->foo * sizeof(char));
> + EXPECT(__builtin_dynamic_object_size(p->array, 1), p->foo * sizeof(char));
> + EXPECT(__builtin_dynamic_object_size(p->array, 2), p->foo * sizeof(char));
> + EXPECT(__builtin_dynamic_object_size(p->array, 3), p->foo * sizeof(char));
> + /*when checking the pointer p, we have no observed allocation nor observed
> + access, therefore, we cannot determine the size info here. */
> + EXPECT(__builtin_dynamic_object_size(p, 0), -1);
> + EXPECT(__builtin_dynamic_object_size(p, 1), -1);
> + EXPECT(__builtin_dynamic_object_size(p, 2), 0);
> + EXPECT(__builtin_dynamic_object_size(p, 3), 0);
> +
> + /*when checking the access p->array, we only have info on the counted-by
> + value. */
> + EXPECT(__builtin_dynamic_object_size(q->array, 0), q->foo * sizeof(char));
> + EXPECT(__builtin_dynamic_object_size(q->array, 1), q->foo * sizeof(char));
> + EXPECT(__builtin_dynamic_object_size(q->array, 2), q->foo * sizeof(char));
> + EXPECT(__builtin_dynamic_object_size(q->array, 3), q->foo * sizeof(char));
> + /*when checking the pointer p, we have no observed allocation nor observed
> + access, therefore, we cannot determine the size info here. */
> + EXPECT(__builtin_dynamic_object_size(q, 0), -1);
> + EXPECT(__builtin_dynamic_object_size(q, 1), -1);
> + EXPECT(__builtin_dynamic_object_size(q, 2), 0);
> + EXPECT(__builtin_dynamic_object_size(q, 3), 0);
> +
> + DONE ();
> +}
> diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
> new file mode 100644
> index 000000000000..37fc215e5e5c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
> @@ -0,0 +1,48 @@
> +/* test the attribute counted_by and its usage in
> + * __builtin_dynamic_object_size. when the counted_by field is negative. */
> +/* { dg-do run } */
> +/* { dg-options "-O2" } */
> +
> +#include "builtin-object-size-common.h"
> +
> +struct annotated {
> + int b;
> + int c[] __attribute__ ((counted_by (b)));
> +} *array_annotated;
> +
> +struct nested_annotated {
> + struct {
> + union {
> + int b;
> + float f;
> + };
> + int n;
> + };
> + int c[] __attribute__ ((counted_by (b)));
> +} *array_nested_annotated;
> +
> +void __attribute__((__noinline__)) setup (int attr_count)
> +{
> + array_annotated
> + = (struct annotated *)malloc (sizeof (struct annotated));
> + array_annotated->b = attr_count;
> +
> + array_nested_annotated
> + = (struct nested_annotated *)malloc (sizeof (struct nested_annotated));
> + array_nested_annotated->b = attr_count -1;
> +
> + return;
> +}
> +
> +void __attribute__((__noinline__)) test ()
> +{
> + EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1), 0);
> + EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1), 0);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + setup (-10);
> + test ();
> + DONE ();
> +}
> diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
> index 018fbc30cbb6..630b0a7aaa4b 100644
> --- a/gcc/tree-object-size.cc
> +++ b/gcc/tree-object-size.cc
> @@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
> #include "attribs.h"
> #include "builtins.h"
> #include "gimplify-me.h"
> +#include "gimplify.h"
>
> struct object_size_info
> {
> @@ -60,6 +61,7 @@ static tree compute_object_offset (tree, const_tree);
> static bool addr_object_size (struct object_size_info *,
> const_tree, int, tree *, tree *t = NULL);
> static tree alloc_object_size (const gcall *, int);
> +static tree access_with_size_object_size (const gcall *, int);
> static tree pass_through_call (const gcall *);
> static void collect_object_sizes_for (struct object_size_info *, tree);
> static void expr_object_size (struct object_size_info *, tree, tree);
> @@ -749,6 +751,59 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
> return false;
> }
>
> +/* Compute __builtin_object_size for a CALL to .ACCESS_WITH_SIZE,
> + OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
> + the 2nd, 3rd, and the 4th parameters of the call determine the size of
Capitalize "The"
> + the CALL:
> +
> + 2nd argument REF_TO_SIZE: The reference to the size of the object,
> + 3rd argument CLASS_OF_SIZE: The size referenced by the REF_TO_SIZE represents
> + 0: unknown;
> + 1: the number of the elements of the object type;
> + 2: the number of bytes;
> + 4th argument TYPE_OF_SIZE: A constant 0 with the TYPE of the object
> + refed by REF_TO_SIZE
s/refed/referenced/ Maybe rephrase this as the following?
A constant 0 with its TYPE being the same as the TYPE of the object
referenced by REF_TO_SIZE.
> +
> + the size of the element can be retrived from the result type of the call,
s/retrived/retrieved/ Also capitalize the first "The".
> + which is the pointer to the array type. */
> +static tree
> +access_with_size_object_size (const gcall *call, int object_size_type)
> +{
This should probably bail out if object_size_type & OST_DYNAMIC == 0.
> + gcc_assert (gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE));
> + /* result type is a pointer type to the original flexible array type. */
> + tree result_type = gimple_call_return_type (call);
> + gcc_assert (POINTER_TYPE_P (result_type));
> + tree element_size = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (result_type)));
> + tree ref_to_size = gimple_call_arg (call, 1);
> + unsigned int type_of_size = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
Shouldn't this be class_of_size?
> + tree type = TREE_TYPE (gimple_call_arg (call, 3));
> +
> + tree size = fold_build2 (MEM_REF, type, ref_to_size,
> + build_int_cst (ptr_type_node, 0));
> +
> + /* If size is negative value, treat it as zero. */
> + if (!TYPE_UNSIGNED (type))
> + {
> + tree cond_expr = fold_build2 (LT_EXPR, boolean_type_node,
> + unshare_expr (size), build_zero_cst (type));
> + size = fold_build3 (COND_EXPR, integer_type_node, cond_expr,
> + build_zero_cst (type), size);
> + }
> +
> + if (type_of_size == 0)
> + return size_unknown (object_size_type);
> + else if (type_of_size == 1)
> + size = size_binop (MULT_EXPR,
> + fold_convert (sizetype, size),
> + fold_convert (sizetype, element_size));
> + else
> + size = fold_convert (sizetype, size);
> +
> + if (!todo)
> + todo = TODO_update_ssa_only_virtuals;
> +
> + return size;
> +}
>
> /* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL.
> Handles calls to functions declared with attribute alloc_size.
> @@ -1350,8 +1405,12 @@ call_object_size (struct object_size_info *osi, tree ptr, gcall *call)
>
> bool is_strdup = gimple_call_builtin_p (call, BUILT_IN_STRDUP);
> bool is_strndup = gimple_call_builtin_p (call, BUILT_IN_STRNDUP);
> + bool is_access_with_size
> + = gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE);
> if (is_strdup || is_strndup)
> bytes = strdup_object_size (call, object_size_type, is_strndup);
> + else if (is_access_with_size)
> + bytes = access_with_size_object_size (call, object_size_type);
> else
> bytes = alloc_object_size (call, object_size_type);
>
On Mar 11, 2024, at 13:11, Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
On 2024-02-16 14:47, Qing Zhao wrote:
gcc/ChangeLog:
* tree-object-size.cc (access_with_size_object_size): New function.
(call_object_size): Call the new function.
gcc/testsuite/ChangeLog:
* gcc.dg/builtin-object-size-common.h: Add a new macro EXPECT.
* gcc.dg/flex-array-counted-by-3.c: New test.
* gcc.dg/flex-array-counted-by-4.c: New test.
* gcc.dg/flex-array-counted-by-5.c: New test.
---
.../gcc.dg/builtin-object-size-common.h | 11 ++
.../gcc.dg/flex-array-counted-by-3.c | 63 +++++++
.../gcc.dg/flex-array-counted-by-4.c | 178 ++++++++++++++++++
.../gcc.dg/flex-array-counted-by-5.c | 48 +++++
gcc/tree-object-size.cc | 59 ++++++
5 files changed, 359 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-common.h b/gcc/testsuite/gcc.dg/builtin-object-size-common.h
index 66ff7cdd953a..b677067c6e6b 100644
--- a/gcc/testsuite/gcc.dg/builtin-object-size-common.h
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-common.h
@@ -30,3 +30,14 @@ unsigned nfails = 0;
__builtin_abort (); \
return 0; \
} while (0)
+
+#define EXPECT(p, _v) do { \
+ size_t v = _v; \
+ if (p == v) \
+ __builtin_printf ("ok: %s == %zd\n", #p, p); \
+ else \
+ { \
+ __builtin_printf ("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
+ FAIL (); \
+ } \
+} while (0);
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
new file mode 100644
index 000000000000..0066c32ca808
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
@@ -0,0 +1,63 @@
+/* test the attribute counted_by and its usage in
+ * __builtin_dynamic_object_size. */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "builtin-object-size-common.h"
+
+struct flex {
+ int b;
+ int c[];
+} *array_flex;
+
+struct annotated {
+ int b;
+ int c[] __attribute__ ((counted_by (b)));
+} *array_annotated;
+
+struct nested_annotated {
+ struct {
+ union {
+ int b;
+ float f;
+ };
+ int n;
+ };
+ int c[] __attribute__ ((counted_by (b)));
+} *array_nested_annotated;
+
+void __attribute__((__noinline__)) setup (int normal_count, int attr_count)
+{
+ array_flex
+ = (struct flex *)malloc (sizeof (struct flex)
+ + normal_count * sizeof (int));
+ array_flex->b = normal_count;
+
+ array_annotated
+ = (struct annotated *)malloc (sizeof (struct annotated)
+ + attr_count * sizeof (int));
+ array_annotated->b = attr_count;
+
+ array_nested_annotated
+ = (struct nested_annotated *)malloc (sizeof (struct nested_annotated)
+ + attr_count * sizeof (int));
+ array_nested_annotated->b = attr_count;
+
+ return;
+}
+
+void __attribute__((__noinline__)) test ()
+{
+ EXPECT(__builtin_dynamic_object_size(array_flex->c, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1),
+ array_annotated->b * sizeof (int));
+ EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1),
+ array_nested_annotated->b * sizeof (int));
+}
+
+int main(int argc, char *argv[])
+{
+ setup (10,10);
+ test ();
+ DONE ();
+}
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
new file mode 100644
index 000000000000..3ce7f3545549
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
@@ -0,0 +1,178 @@
+/* test the attribute counted_by and its usage in
+__builtin_dynamic_object_size: what's the correct behavior when the
+allocation size mismatched with the value of counted_by attribute?
+we should always use the latest value that is hold by the counted_by
+field. */
+/* { dg-do run } */
+/* { dg-options "-O -fstrict-flex-arrays=3" } */
+
+#include "builtin-object-size-common.h"
+
+struct annotated {
+ size_t foo;
+ char others;
+ char array[] __attribute__((counted_by (foo)));
+};
+
+#define noinline __attribute__((__noinline__))
+#define SIZE_BUMP 10
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+/* In general, Due to type casting, the type for the pointee of a pointer
+ does not say anything about the object it points to,
+ So, __builtin_object_size can not directly use the type of the pointee
+ to decide the size of the object the pointer points to.
+
+ there are only two reliable ways:
+ A. observed allocations (call to the allocation functions in the routine)
+ B. observed accesses (read or write access to the location of the
+ pointer points to)
+
+ that provide information about the type/existence of an object at
+ the corresponding address.
+
+ for A, we use the "alloc_size" attribute for the corresponding allocation
+ functions to determine the object size;
+ (We treat counted_by attribute the same as the "alloc_size" attribute)
+
+ For B, we use the SIZE info of the TYPE attached to the corresponding access.
+
+ The only other way in C which ensures that a pointer actually points
+ to an object of the correct type is 'static':
+
+ void foo(struct P *p[static 1]);
+
+ See https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624814.html
+ for more details. */
+
+/* in the following function, malloc allocated more space than the value
+ of counted_by attribute. Then what's the correct behavior we expect
+ the __builtin_dynamic_object_size should have for each of the cases? */
+
+static struct annotated * noinline alloc_buf_more (size_t index)
+{
+ struct annotated *p;
+ size_t allocated_size
+ = MAX (sizeof (struct annotated),
+ (__builtin_offsetof (struct annotated, array[0])
+ + (index + SIZE_BUMP) * sizeof (char)));
+ p = (struct annotated *) malloc (allocated_size);
+
+ p->foo = index;
+
+ /*when checking the observed access p->array, we have info on both
+ observered allocation and observed access,
+ A.1 from observed allocation:
+ allocated_size - offsetof (struct annotated, array[0])
+
+ A.2 from the counted-by attribute:
+ p->foo * sizeof (char)
+
+ we always use the latest value that is hold by the counted-by field.
+ */
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 0),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 1),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 2),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 3),
+ (p->foo) * sizeof(char));
+
+ /*when checking the pointer p, we only have info on the observed allocation.
+ So, the object size info can only been obtained from the call to malloc.
+ for both MAXIMUM and MINIMUM: A = (index + SIZE_BUMP) * sizeof (char) */
+ EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
+ return p;
+}
+
+/* in the following function, malloc allocated less space than the value
+ of counted_by attribute. Then what's the correct behavior we expect
+ the __builtin_dynamic_object_size should have for each of the cases?
+ NOTE: this is an user error, GCC should issue warnings for such case.
+ this is a seperate issue we should address later. */
+
+static struct annotated * noinline alloc_buf_less (size_t index)
+{
+ struct annotated *p;
+ size_t allocated_size
+ = MAX (sizeof (struct annotated),
+ (__builtin_offsetof (struct annotated, array[0])
+ + (index) * sizeof (char)));
+ p = (struct annotated *) malloc (allocated_size);
+
+ p->foo = index + SIZE_BUMP;
+
+ /*when checking the observed access p->array, we have info on both
+ observered allocation and observed access,
+ A.1 from observed allocation:
+ allocated_size - offsetof (struct annotated, array[0])
+ A.2 from the counted-by attribute:
+ p->foo * sizeof (char)
+
+ we always use the latest value that is hold by the counted-by field.
+ */
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 0),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 1),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 2),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 3),
+ (p->foo) * sizeof(char));
+
+ /*when checking the pointer p, we only have info on the observed
+ allocation. So, the object size info can only been obtained from
+ the call to malloc. */
+ EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
+ return p;
+}
+
+int main ()
+{
+ struct annotated *p, *q;
+ p = alloc_buf_more (10);
+ q = alloc_buf_less (10);
+
+ /*when checking the access p->array, we only have info on the counted-by
+ value. */
+ EXPECT(__builtin_dynamic_object_size(p->array, 0), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 1), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 2), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 3), p->foo * sizeof(char));
+ /*when checking the pointer p, we have no observed allocation nor observed
+ access, therefore, we cannot determine the size info here. */
+ EXPECT(__builtin_dynamic_object_size(p, 0), -1);
+ EXPECT(__builtin_dynamic_object_size(p, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(p, 2), 0);
+ EXPECT(__builtin_dynamic_object_size(p, 3), 0);
+
+ /*when checking the access p->array, we only have info on the counted-by
+ value. */
+ EXPECT(__builtin_dynamic_object_size(q->array, 0), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 1), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 2), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 3), q->foo * sizeof(char));
+ /*when checking the pointer p, we have no observed allocation nor observed
+ access, therefore, we cannot determine the size info here. */
+ EXPECT(__builtin_dynamic_object_size(q, 0), -1);
+ EXPECT(__builtin_dynamic_object_size(q, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(q, 2), 0);
+ EXPECT(__builtin_dynamic_object_size(q, 3), 0);
+
+ DONE ();
+}
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
new file mode 100644
index 000000000000..37fc215e5e5c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
@@ -0,0 +1,48 @@
+/* test the attribute counted_by and its usage in
+ * __builtin_dynamic_object_size. when the counted_by field is negative. */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "builtin-object-size-common.h"
+
+struct annotated {
+ int b;
+ int c[] __attribute__ ((counted_by (b)));
+} *array_annotated;
+
+struct nested_annotated {
+ struct {
+ union {
+ int b;
+ float f;
+ };
+ int n;
+ };
+ int c[] __attribute__ ((counted_by (b)));
+} *array_nested_annotated;
+
+void __attribute__((__noinline__)) setup (int attr_count)
+{
+ array_annotated
+ = (struct annotated *)malloc (sizeof (struct annotated));
+ array_annotated->b = attr_count;
+
+ array_nested_annotated
+ = (struct nested_annotated *)malloc (sizeof (struct nested_annotated));
+ array_nested_annotated->b = attr_count -1;
+
+ return;
+}
+
+void __attribute__((__noinline__)) test ()
+{
+ EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1), 0);
+ EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1), 0);
+}
+
+int main(int argc, char *argv[])
+{
+ setup (-10);
+ test ();
+ DONE ();
+}
diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
index 018fbc30cbb6..630b0a7aaa4b 100644
--- a/gcc/tree-object-size.cc
+++ b/gcc/tree-object-size.cc
@@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
#include "attribs.h"
#include "builtins.h"
#include "gimplify-me.h"
+#include "gimplify.h"
struct object_size_info
{
@@ -60,6 +61,7 @@ static tree compute_object_offset (tree, const_tree);
static bool addr_object_size (struct object_size_info *,
const_tree, int, tree *, tree *t = NULL);
static tree alloc_object_size (const gcall *, int);
+static tree access_with_size_object_size (const gcall *, int);
static tree pass_through_call (const gcall *);
static void collect_object_sizes_for (struct object_size_info *, tree);
static void expr_object_size (struct object_size_info *, tree, tree);
@@ -749,6 +751,59 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
return false;
}
+/* Compute __builtin_object_size for a CALL to .ACCESS_WITH_SIZE,
+ OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
+ the 2nd, 3rd, and the 4th parameters of the call determine the size of
Capitalize “The”
Okay.
+ the CALL:
+
+ 2nd argument REF_TO_SIZE: The reference to the size of the object,
+ 3rd argument CLASS_OF_SIZE: The size referenced by the REF_TO_SIZE represents
+ 0: unknown;
+ 1: the number of the elements of the object type;
+ 2: the number of bytes;
+ 4th argument TYPE_OF_SIZE: A constant 0 with the TYPE of the object
+ refed by REF_TO_SIZE
s/refed/referenced/ Maybe rephrase this as the following?
A constant 0 with its TYPE being the same as the TYPE of the object
referenced by REF_TO_SIZE.
Okay, will update this.
+
+ the size of the element can be retrived from the result type of the call,
s/retrived/retrieved/ Also capitalize the first "The”.
Okay.
+ which is the pointer to the array type. */
+static tree
+access_with_size_object_size (const gcall *call, int object_size_type)
+{
This should probably bail out if object_size_type & OST_DYNAMIC == 0.
Okay. Will add this.
+ gcc_assert (gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE));
+ /* result type is a pointer type to the original flexible array type. */
+ tree result_type = gimple_call_return_type (call);
+ gcc_assert (POINTER_TYPE_P (result_type));
+ tree element_size = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (result_type)));
+ tree ref_to_size = gimple_call_arg (call, 1);
+ unsigned int type_of_size = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
Shouldn't this be class_of_size?
Will update this when I changed the 3rd argument per the previous discussion.
Qing
+ tree type = TREE_TYPE (gimple_call_arg (call, 3));
+
+ tree size = fold_build2 (MEM_REF, type, ref_to_size,
+ build_int_cst (ptr_type_node, 0));
+
+ /* If size is negative value, treat it as zero. */
+ if (!TYPE_UNSIGNED (type))
+ {
+ tree cond_expr = fold_build2 (LT_EXPR, boolean_type_node,
+ unshare_expr (size), build_zero_cst (type));
+ size = fold_build3 (COND_EXPR, integer_type_node, cond_expr,
+ build_zero_cst (type), size);
+ }
+
+ if (type_of_size == 0)
+ return size_unknown (object_size_type);
+ else if (type_of_size == 1)
+ size = size_binop (MULT_EXPR,
+ fold_convert (sizetype, size),
+ fold_convert (sizetype, element_size));
+ else
+ size = fold_convert (sizetype, size);
+
+ if (!todo)
+ todo = TODO_update_ssa_only_virtuals;
+
+ return size;
+}
/* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL.
Handles calls to functions declared with attribute alloc_size.
@@ -1350,8 +1405,12 @@ call_object_size (struct object_size_info *osi, tree ptr, gcall *call)
bool is_strdup = gimple_call_builtin_p (call, BUILT_IN_STRDUP);
bool is_strndup = gimple_call_builtin_p (call, BUILT_IN_STRNDUP);
+ bool is_access_with_size
+ = gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE);
if (is_strdup || is_strndup)
bytes = strdup_object_size (call, object_size_type, is_strndup);
+ else if (is_access_with_size)
+ bytes = access_with_size_object_size (call, object_size_type);
else
bytes = alloc_object_size (call, object_size_type);
On Mar 13, 2024, at 15:17, Qing Zhao <qing.zhao@oracle.com> wrote:
On Mar 11, 2024, at 13:11, Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
On 2024-02-16 14:47, Qing Zhao wrote:
gcc/ChangeLog:
* tree-object-size.cc (access_with_size_object_size): New function.
(call_object_size): Call the new function.
gcc/testsuite/ChangeLog:
* gcc.dg/builtin-object-size-common.h: Add a new macro EXPECT.
* gcc.dg/flex-array-counted-by-3.c: New test.
* gcc.dg/flex-array-counted-by-4.c: New test.
* gcc.dg/flex-array-counted-by-5.c: New test.
---
.../gcc.dg/builtin-object-size-common.h | 11 ++
.../gcc.dg/flex-array-counted-by-3.c | 63 +++++++
.../gcc.dg/flex-array-counted-by-4.c | 178 ++++++++++++++++++
.../gcc.dg/flex-array-counted-by-5.c | 48 +++++
gcc/tree-object-size.cc | 59 ++++++
5 files changed, 359 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
create mode 100644 gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-common.h b/gcc/testsuite/gcc.dg/builtin-object-size-common.h
index 66ff7cdd953a..b677067c6e6b 100644
--- a/gcc/testsuite/gcc.dg/builtin-object-size-common.h
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-common.h
@@ -30,3 +30,14 @@ unsigned nfails = 0;
__builtin_abort (); \
return 0; \
} while (0)
+
+#define EXPECT(p, _v) do { \
+ size_t v = _v; \
+ if (p == v) \
+ __builtin_printf ("ok: %s == %zd\n", #p, p); \
+ else \
+ { \
+ __builtin_printf ("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
+ FAIL (); \
+ } \
+} while (0);
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
new file mode 100644
index 000000000000..0066c32ca808
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-3.c
@@ -0,0 +1,63 @@
+/* test the attribute counted_by and its usage in
+ * __builtin_dynamic_object_size. */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "builtin-object-size-common.h"
+
+struct flex {
+ int b;
+ int c[];
+} *array_flex;
+
+struct annotated {
+ int b;
+ int c[] __attribute__ ((counted_by (b)));
+} *array_annotated;
+
+struct nested_annotated {
+ struct {
+ union {
+ int b;
+ float f;
+ };
+ int n;
+ };
+ int c[] __attribute__ ((counted_by (b)));
+} *array_nested_annotated;
+
+void __attribute__((__noinline__)) setup (int normal_count, int attr_count)
+{
+ array_flex
+ = (struct flex *)malloc (sizeof (struct flex)
+ + normal_count * sizeof (int));
+ array_flex->b = normal_count;
+
+ array_annotated
+ = (struct annotated *)malloc (sizeof (struct annotated)
+ + attr_count * sizeof (int));
+ array_annotated->b = attr_count;
+
+ array_nested_annotated
+ = (struct nested_annotated *)malloc (sizeof (struct nested_annotated)
+ + attr_count * sizeof (int));
+ array_nested_annotated->b = attr_count;
+
+ return;
+}
+
+void __attribute__((__noinline__)) test ()
+{
+ EXPECT(__builtin_dynamic_object_size(array_flex->c, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1),
+ array_annotated->b * sizeof (int));
+ EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1),
+ array_nested_annotated->b * sizeof (int));
+}
+
+int main(int argc, char *argv[])
+{
+ setup (10,10);
+ test ();
+ DONE ();
+}
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
new file mode 100644
index 000000000000..3ce7f3545549
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-4.c
@@ -0,0 +1,178 @@
+/* test the attribute counted_by and its usage in
+__builtin_dynamic_object_size: what's the correct behavior when the
+allocation size mismatched with the value of counted_by attribute?
+we should always use the latest value that is hold by the counted_by
+field. */
+/* { dg-do run } */
+/* { dg-options "-O -fstrict-flex-arrays=3" } */
+
+#include "builtin-object-size-common.h"
+
+struct annotated {
+ size_t foo;
+ char others;
+ char array[] __attribute__((counted_by (foo)));
+};
+
+#define noinline __attribute__((__noinline__))
+#define SIZE_BUMP 10
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+/* In general, Due to type casting, the type for the pointee of a pointer
+ does not say anything about the object it points to,
+ So, __builtin_object_size can not directly use the type of the pointee
+ to decide the size of the object the pointer points to.
+
+ there are only two reliable ways:
+ A. observed allocations (call to the allocation functions in the routine)
+ B. observed accesses (read or write access to the location of the
+ pointer points to)
+
+ that provide information about the type/existence of an object at
+ the corresponding address.
+
+ for A, we use the "alloc_size" attribute for the corresponding allocation
+ functions to determine the object size;
+ (We treat counted_by attribute the same as the "alloc_size" attribute)
+
+ For B, we use the SIZE info of the TYPE attached to the corresponding access.
+
+ The only other way in C which ensures that a pointer actually points
+ to an object of the correct type is 'static':
+
+ void foo(struct P *p[static 1]);
+
+ See https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624814.html
+ for more details. */
+
+/* in the following function, malloc allocated more space than the value
+ of counted_by attribute. Then what's the correct behavior we expect
+ the __builtin_dynamic_object_size should have for each of the cases? */
+
+static struct annotated * noinline alloc_buf_more (size_t index)
+{
+ struct annotated *p;
+ size_t allocated_size
+ = MAX (sizeof (struct annotated),
+ (__builtin_offsetof (struct annotated, array[0])
+ + (index + SIZE_BUMP) * sizeof (char)));
+ p = (struct annotated *) malloc (allocated_size);
+
+ p->foo = index;
+
+ /*when checking the observed access p->array, we have info on both
+ observered allocation and observed access,
+ A.1 from observed allocation:
+ allocated_size - offsetof (struct annotated, array[0])
+
+ A.2 from the counted-by attribute:
+ p->foo * sizeof (char)
+
+ we always use the latest value that is hold by the counted-by field.
+ */
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 0),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 1),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 2),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 3),
+ (p->foo) * sizeof(char));
+
+ /*when checking the pointer p, we only have info on the observed allocation.
+ So, the object size info can only been obtained from the call to malloc.
+ for both MAXIMUM and MINIMUM: A = (index + SIZE_BUMP) * sizeof (char) */
+ EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
+ return p;
+}
+
+/* in the following function, malloc allocated less space than the value
+ of counted_by attribute. Then what's the correct behavior we expect
+ the __builtin_dynamic_object_size should have for each of the cases?
+ NOTE: this is an user error, GCC should issue warnings for such case.
+ this is a seperate issue we should address later. */
+
+static struct annotated * noinline alloc_buf_less (size_t index)
+{
+ struct annotated *p;
+ size_t allocated_size
+ = MAX (sizeof (struct annotated),
+ (__builtin_offsetof (struct annotated, array[0])
+ + (index) * sizeof (char)));
+ p = (struct annotated *) malloc (allocated_size);
+
+ p->foo = index + SIZE_BUMP;
+
+ /*when checking the observed access p->array, we have info on both
+ observered allocation and observed access,
+ A.1 from observed allocation:
+ allocated_size - offsetof (struct annotated, array[0])
+ A.2 from the counted-by attribute:
+ p->foo * sizeof (char)
+
+ we always use the latest value that is hold by the counted-by field.
+ */
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 0),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 1),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 2),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 3),
+ (p->foo) * sizeof(char));
+
+ /*when checking the pointer p, we only have info on the observed
+ allocation. So, the object size info can only been obtained from
+ the call to malloc. */
+ EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
+ return p;
+}
+
+int main ()
+{
+ struct annotated *p, *q;
+ p = alloc_buf_more (10);
+ q = alloc_buf_less (10);
+
+ /*when checking the access p->array, we only have info on the counted-by
+ value. */
+ EXPECT(__builtin_dynamic_object_size(p->array, 0), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 1), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 2), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 3), p->foo * sizeof(char));
+ /*when checking the pointer p, we have no observed allocation nor observed
+ access, therefore, we cannot determine the size info here. */
+ EXPECT(__builtin_dynamic_object_size(p, 0), -1);
+ EXPECT(__builtin_dynamic_object_size(p, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(p, 2), 0);
+ EXPECT(__builtin_dynamic_object_size(p, 3), 0);
+
+ /*when checking the access p->array, we only have info on the counted-by
+ value. */
+ EXPECT(__builtin_dynamic_object_size(q->array, 0), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 1), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 2), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 3), q->foo * sizeof(char));
+ /*when checking the pointer p, we have no observed allocation nor observed
+ access, therefore, we cannot determine the size info here. */
+ EXPECT(__builtin_dynamic_object_size(q, 0), -1);
+ EXPECT(__builtin_dynamic_object_size(q, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(q, 2), 0);
+ EXPECT(__builtin_dynamic_object_size(q, 3), 0);
+
+ DONE ();
+}
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c b/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
new file mode 100644
index 000000000000..37fc215e5e5c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-5.c
@@ -0,0 +1,48 @@
+/* test the attribute counted_by and its usage in
+ * __builtin_dynamic_object_size. when the counted_by field is negative. */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "builtin-object-size-common.h"
+
+struct annotated {
+ int b;
+ int c[] __attribute__ ((counted_by (b)));
+} *array_annotated;
+
+struct nested_annotated {
+ struct {
+ union {
+ int b;
+ float f;
+ };
+ int n;
+ };
+ int c[] __attribute__ ((counted_by (b)));
+} *array_nested_annotated;
+
+void __attribute__((__noinline__)) setup (int attr_count)
+{
+ array_annotated
+ = (struct annotated *)malloc (sizeof (struct annotated));
+ array_annotated->b = attr_count;
+
+ array_nested_annotated
+ = (struct nested_annotated *)malloc (sizeof (struct nested_annotated));
+ array_nested_annotated->b = attr_count -1;
+
+ return;
+}
+
+void __attribute__((__noinline__)) test ()
+{
+ EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1), 0);
+ EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1), 0);
+}
+
+int main(int argc, char *argv[])
+{
+ setup (-10);
+ test ();
+ DONE ();
+}
diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
index 018fbc30cbb6..630b0a7aaa4b 100644
--- a/gcc/tree-object-size.cc
+++ b/gcc/tree-object-size.cc
@@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
#include "attribs.h"
#include "builtins.h"
#include "gimplify-me.h"
+#include "gimplify.h"
struct object_size_info
{
@@ -60,6 +61,7 @@ static tree compute_object_offset (tree, const_tree);
static bool addr_object_size (struct object_size_info *,
const_tree, int, tree *, tree *t = NULL);
static tree alloc_object_size (const gcall *, int);
+static tree access_with_size_object_size (const gcall *, int);
static tree pass_through_call (const gcall *);
static void collect_object_sizes_for (struct object_size_info *, tree);
static void expr_object_size (struct object_size_info *, tree, tree);
@@ -749,6 +751,59 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
return false;
}
+/* Compute __builtin_object_size for a CALL to .ACCESS_WITH_SIZE,
+ OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
+ the 2nd, 3rd, and the 4th parameters of the call determine the size of
Capitalize “The”
Okay.
+ the CALL:
+
+ 2nd argument REF_TO_SIZE: The reference to the size of the object,
+ 3rd argument CLASS_OF_SIZE: The size referenced by the REF_TO_SIZE represents
+ 0: unknown;
+ 1: the number of the elements of the object type;
+ 2: the number of bytes;
+ 4th argument TYPE_OF_SIZE: A constant 0 with the TYPE of the object
+ refed by REF_TO_SIZE
s/refed/referenced/ Maybe rephrase this as the following?
A constant 0 with its TYPE being the same as the TYPE of the object
referenced by REF_TO_SIZE.
Okay, will update this.
+
+ the size of the element can be retrived from the result type of the call,
s/retrived/retrieved/ Also capitalize the first "The”.
Okay.
+ which is the pointer to the array type. */
+static tree
+access_with_size_object_size (const gcall *call, int object_size_type)
+{
This should probably bail out if object_size_type & OST_DYNAMIC == 0.
Okay. Will add this.
When add this into access_with_size_object_size, I found some old bugs in early_object_sizes_execute_one, and fixed them as well.
thanks.
Qing
+ gcc_assert (gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE));
+ /* result type is a pointer type to the original flexible array type. */
+ tree result_type = gimple_call_return_type (call);
+ gcc_assert (POINTER_TYPE_P (result_type));
+ tree element_size = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (result_type)));
+ tree ref_to_size = gimple_call_arg (call, 1);
+ unsigned int type_of_size = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
Shouldn't this be class_of_size?
Will update this when I changed the 3rd argument per the previous discussion.
Qing
+ tree type = TREE_TYPE (gimple_call_arg (call, 3));
+
+ tree size = fold_build2 (MEM_REF, type, ref_to_size,
+ build_int_cst (ptr_type_node, 0));
+
+ /* If size is negative value, treat it as zero. */
+ if (!TYPE_UNSIGNED (type))
+ {
+ tree cond_expr = fold_build2 (LT_EXPR, boolean_type_node,
+ unshare_expr (size), build_zero_cst (type));
+ size = fold_build3 (COND_EXPR, integer_type_node, cond_expr,
+ build_zero_cst (type), size);
+ }
+
+ if (type_of_size == 0)
+ return size_unknown (object_size_type);
+ else if (type_of_size == 1)
+ size = size_binop (MULT_EXPR,
+ fold_convert (sizetype, size),
+ fold_convert (sizetype, element_size));
+ else
+ size = fold_convert (sizetype, size);
+
+ if (!todo)
+ todo = TODO_update_ssa_only_virtuals;
+
+ return size;
+}
/* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL.
Handles calls to functions declared with attribute alloc_size.
@@ -1350,8 +1405,12 @@ call_object_size (struct object_size_info *osi, tree ptr, gcall *call)
bool is_strdup = gimple_call_builtin_p (call, BUILT_IN_STRDUP);
bool is_strndup = gimple_call_builtin_p (call, BUILT_IN_STRNDUP);
+ bool is_access_with_size
+ = gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE);
if (is_strdup || is_strndup)
bytes = strdup_object_size (call, object_size_type, is_strndup);
+ else if (is_access_with_size)
+ bytes = access_with_size_object_size (call, object_size_type);
else
bytes = alloc_object_size (call, object_size_type);
On 2024-03-18 12:28, Qing Zhao wrote:
>>> This should probably bail out if object_size_type & OST_DYNAMIC == 0.
>> Okay. Will add this.
>
> When add this into access_with_size_object_size, I found some old bugs
> in early_object_sizes_execute_one, and fixed them as well.
>
Would you be able to isolate this fix and post them separately? I
reckon they would be relevant for gcc 14 too.
Thanks,
Sid
> On Mar 18, 2024, at 12:30, Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
>
> On 2024-03-18 12:28, Qing Zhao wrote:
>>>> This should probably bail out if object_size_type & OST_DYNAMIC == 0.
>>> Okay. Will add this.
>> When add this into access_with_size_object_size, I found some old bugs in early_object_sizes_execute_one, and fixed them as well.
>
> Would you be able to isolate this fix and post them separately? I reckon they would be relevant for gcc 14 too.
Yes, that’s a good idea, I can do that.
No specific testing case for it, though.
thanks.
Qing
>
> Thanks,
> Sid
@@ -30,3 +30,14 @@ unsigned nfails = 0;
__builtin_abort (); \
return 0; \
} while (0)
+
+#define EXPECT(p, _v) do { \
+ size_t v = _v; \
+ if (p == v) \
+ __builtin_printf ("ok: %s == %zd\n", #p, p); \
+ else \
+ { \
+ __builtin_printf ("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
+ FAIL (); \
+ } \
+} while (0);
new file mode 100644
@@ -0,0 +1,63 @@
+/* test the attribute counted_by and its usage in
+ * __builtin_dynamic_object_size. */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "builtin-object-size-common.h"
+
+struct flex {
+ int b;
+ int c[];
+} *array_flex;
+
+struct annotated {
+ int b;
+ int c[] __attribute__ ((counted_by (b)));
+} *array_annotated;
+
+struct nested_annotated {
+ struct {
+ union {
+ int b;
+ float f;
+ };
+ int n;
+ };
+ int c[] __attribute__ ((counted_by (b)));
+} *array_nested_annotated;
+
+void __attribute__((__noinline__)) setup (int normal_count, int attr_count)
+{
+ array_flex
+ = (struct flex *)malloc (sizeof (struct flex)
+ + normal_count * sizeof (int));
+ array_flex->b = normal_count;
+
+ array_annotated
+ = (struct annotated *)malloc (sizeof (struct annotated)
+ + attr_count * sizeof (int));
+ array_annotated->b = attr_count;
+
+ array_nested_annotated
+ = (struct nested_annotated *)malloc (sizeof (struct nested_annotated)
+ + attr_count * sizeof (int));
+ array_nested_annotated->b = attr_count;
+
+ return;
+}
+
+void __attribute__((__noinline__)) test ()
+{
+ EXPECT(__builtin_dynamic_object_size(array_flex->c, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1),
+ array_annotated->b * sizeof (int));
+ EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1),
+ array_nested_annotated->b * sizeof (int));
+}
+
+int main(int argc, char *argv[])
+{
+ setup (10,10);
+ test ();
+ DONE ();
+}
new file mode 100644
@@ -0,0 +1,178 @@
+/* test the attribute counted_by and its usage in
+__builtin_dynamic_object_size: what's the correct behavior when the
+allocation size mismatched with the value of counted_by attribute?
+we should always use the latest value that is hold by the counted_by
+field. */
+/* { dg-do run } */
+/* { dg-options "-O -fstrict-flex-arrays=3" } */
+
+#include "builtin-object-size-common.h"
+
+struct annotated {
+ size_t foo;
+ char others;
+ char array[] __attribute__((counted_by (foo)));
+};
+
+#define noinline __attribute__((__noinline__))
+#define SIZE_BUMP 10
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+/* In general, Due to type casting, the type for the pointee of a pointer
+ does not say anything about the object it points to,
+ So, __builtin_object_size can not directly use the type of the pointee
+ to decide the size of the object the pointer points to.
+
+ there are only two reliable ways:
+ A. observed allocations (call to the allocation functions in the routine)
+ B. observed accesses (read or write access to the location of the
+ pointer points to)
+
+ that provide information about the type/existence of an object at
+ the corresponding address.
+
+ for A, we use the "alloc_size" attribute for the corresponding allocation
+ functions to determine the object size;
+ (We treat counted_by attribute the same as the "alloc_size" attribute)
+
+ For B, we use the SIZE info of the TYPE attached to the corresponding access.
+
+ The only other way in C which ensures that a pointer actually points
+ to an object of the correct type is 'static':
+
+ void foo(struct P *p[static 1]);
+
+ See https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624814.html
+ for more details. */
+
+/* in the following function, malloc allocated more space than the value
+ of counted_by attribute. Then what's the correct behavior we expect
+ the __builtin_dynamic_object_size should have for each of the cases? */
+
+static struct annotated * noinline alloc_buf_more (size_t index)
+{
+ struct annotated *p;
+ size_t allocated_size
+ = MAX (sizeof (struct annotated),
+ (__builtin_offsetof (struct annotated, array[0])
+ + (index + SIZE_BUMP) * sizeof (char)));
+ p = (struct annotated *) malloc (allocated_size);
+
+ p->foo = index;
+
+ /*when checking the observed access p->array, we have info on both
+ observered allocation and observed access,
+ A.1 from observed allocation:
+ allocated_size - offsetof (struct annotated, array[0])
+
+ A.2 from the counted-by attribute:
+ p->foo * sizeof (char)
+
+ we always use the latest value that is hold by the counted-by field.
+ */
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 0),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 1),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 2),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 3),
+ (p->foo) * sizeof(char));
+
+ /*when checking the pointer p, we only have info on the observed allocation.
+ So, the object size info can only been obtained from the call to malloc.
+ for both MAXIMUM and MINIMUM: A = (index + SIZE_BUMP) * sizeof (char) */
+ EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
+ return p;
+}
+
+/* in the following function, malloc allocated less space than the value
+ of counted_by attribute. Then what's the correct behavior we expect
+ the __builtin_dynamic_object_size should have for each of the cases?
+ NOTE: this is an user error, GCC should issue warnings for such case.
+ this is a seperate issue we should address later. */
+
+static struct annotated * noinline alloc_buf_less (size_t index)
+{
+ struct annotated *p;
+ size_t allocated_size
+ = MAX (sizeof (struct annotated),
+ (__builtin_offsetof (struct annotated, array[0])
+ + (index) * sizeof (char)));
+ p = (struct annotated *) malloc (allocated_size);
+
+ p->foo = index + SIZE_BUMP;
+
+ /*when checking the observed access p->array, we have info on both
+ observered allocation and observed access,
+ A.1 from observed allocation:
+ allocated_size - offsetof (struct annotated, array[0])
+ A.2 from the counted-by attribute:
+ p->foo * sizeof (char)
+
+ we always use the latest value that is hold by the counted-by field.
+ */
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 0),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 1),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 2),
+ (p->foo) * sizeof(char));
+
+ EXPECT(__builtin_dynamic_object_size(p->array, 3),
+ (p->foo) * sizeof(char));
+
+ /*when checking the pointer p, we only have info on the observed
+ allocation. So, the object size info can only been obtained from
+ the call to malloc. */
+ EXPECT(__builtin_dynamic_object_size(p, 0), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 1), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 2), allocated_size);
+ EXPECT(__builtin_dynamic_object_size(p, 3), allocated_size);
+ return p;
+}
+
+int main ()
+{
+ struct annotated *p, *q;
+ p = alloc_buf_more (10);
+ q = alloc_buf_less (10);
+
+ /*when checking the access p->array, we only have info on the counted-by
+ value. */
+ EXPECT(__builtin_dynamic_object_size(p->array, 0), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 1), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 2), p->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(p->array, 3), p->foo * sizeof(char));
+ /*when checking the pointer p, we have no observed allocation nor observed
+ access, therefore, we cannot determine the size info here. */
+ EXPECT(__builtin_dynamic_object_size(p, 0), -1);
+ EXPECT(__builtin_dynamic_object_size(p, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(p, 2), 0);
+ EXPECT(__builtin_dynamic_object_size(p, 3), 0);
+
+ /*when checking the access p->array, we only have info on the counted-by
+ value. */
+ EXPECT(__builtin_dynamic_object_size(q->array, 0), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 1), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 2), q->foo * sizeof(char));
+ EXPECT(__builtin_dynamic_object_size(q->array, 3), q->foo * sizeof(char));
+ /*when checking the pointer p, we have no observed allocation nor observed
+ access, therefore, we cannot determine the size info here. */
+ EXPECT(__builtin_dynamic_object_size(q, 0), -1);
+ EXPECT(__builtin_dynamic_object_size(q, 1), -1);
+ EXPECT(__builtin_dynamic_object_size(q, 2), 0);
+ EXPECT(__builtin_dynamic_object_size(q, 3), 0);
+
+ DONE ();
+}
new file mode 100644
@@ -0,0 +1,48 @@
+/* test the attribute counted_by and its usage in
+ * __builtin_dynamic_object_size. when the counted_by field is negative. */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include "builtin-object-size-common.h"
+
+struct annotated {
+ int b;
+ int c[] __attribute__ ((counted_by (b)));
+} *array_annotated;
+
+struct nested_annotated {
+ struct {
+ union {
+ int b;
+ float f;
+ };
+ int n;
+ };
+ int c[] __attribute__ ((counted_by (b)));
+} *array_nested_annotated;
+
+void __attribute__((__noinline__)) setup (int attr_count)
+{
+ array_annotated
+ = (struct annotated *)malloc (sizeof (struct annotated));
+ array_annotated->b = attr_count;
+
+ array_nested_annotated
+ = (struct nested_annotated *)malloc (sizeof (struct nested_annotated));
+ array_nested_annotated->b = attr_count -1;
+
+ return;
+}
+
+void __attribute__((__noinline__)) test ()
+{
+ EXPECT(__builtin_dynamic_object_size(array_annotated->c, 1), 0);
+ EXPECT(__builtin_dynamic_object_size(array_nested_annotated->c, 1), 0);
+}
+
+int main(int argc, char *argv[])
+{
+ setup (-10);
+ test ();
+ DONE ();
+}
@@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see
#include "attribs.h"
#include "builtins.h"
#include "gimplify-me.h"
+#include "gimplify.h"
struct object_size_info
{
@@ -60,6 +61,7 @@ static tree compute_object_offset (tree, const_tree);
static bool addr_object_size (struct object_size_info *,
const_tree, int, tree *, tree *t = NULL);
static tree alloc_object_size (const gcall *, int);
+static tree access_with_size_object_size (const gcall *, int);
static tree pass_through_call (const gcall *);
static void collect_object_sizes_for (struct object_size_info *, tree);
static void expr_object_size (struct object_size_info *, tree, tree);
@@ -749,6 +751,59 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
return false;
}
+/* Compute __builtin_object_size for a CALL to .ACCESS_WITH_SIZE,
+ OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
+ the 2nd, 3rd, and the 4th parameters of the call determine the size of
+ the CALL:
+
+ 2nd argument REF_TO_SIZE: The reference to the size of the object,
+ 3rd argument CLASS_OF_SIZE: The size referenced by the REF_TO_SIZE represents
+ 0: unknown;
+ 1: the number of the elements of the object type;
+ 2: the number of bytes;
+ 4th argument TYPE_OF_SIZE: A constant 0 with the TYPE of the object
+ refed by REF_TO_SIZE
+
+ the size of the element can be retrived from the result type of the call,
+ which is the pointer to the array type. */
+static tree
+access_with_size_object_size (const gcall *call, int object_size_type)
+{
+ gcc_assert (gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE));
+ /* result type is a pointer type to the original flexible array type. */
+ tree result_type = gimple_call_return_type (call);
+ gcc_assert (POINTER_TYPE_P (result_type));
+ tree element_size = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (result_type)));
+ tree ref_to_size = gimple_call_arg (call, 1);
+ unsigned int type_of_size = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
+ tree type = TREE_TYPE (gimple_call_arg (call, 3));
+
+ tree size = fold_build2 (MEM_REF, type, ref_to_size,
+ build_int_cst (ptr_type_node, 0));
+
+ /* If size is negative value, treat it as zero. */
+ if (!TYPE_UNSIGNED (type))
+ {
+ tree cond_expr = fold_build2 (LT_EXPR, boolean_type_node,
+ unshare_expr (size), build_zero_cst (type));
+ size = fold_build3 (COND_EXPR, integer_type_node, cond_expr,
+ build_zero_cst (type), size);
+ }
+
+ if (type_of_size == 0)
+ return size_unknown (object_size_type);
+ else if (type_of_size == 1)
+ size = size_binop (MULT_EXPR,
+ fold_convert (sizetype, size),
+ fold_convert (sizetype, element_size));
+ else
+ size = fold_convert (sizetype, size);
+
+ if (!todo)
+ todo = TODO_update_ssa_only_virtuals;
+
+ return size;
+}
/* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL.
Handles calls to functions declared with attribute alloc_size.
@@ -1350,8 +1405,12 @@ call_object_size (struct object_size_info *osi, tree ptr, gcall *call)
bool is_strdup = gimple_call_builtin_p (call, BUILT_IN_STRDUP);
bool is_strndup = gimple_call_builtin_p (call, BUILT_IN_STRNDUP);
+ bool is_access_with_size
+ = gimple_call_internal_p (call, IFN_ACCESS_WITH_SIZE);
if (is_strdup || is_strndup)
bytes = strdup_object_size (call, object_size_type, is_strndup);
+ else if (is_access_with_size)
+ bytes = access_with_size_object_size (call, object_size_type);
else
bytes = alloc_object_size (call, object_size_type);