> On Feb 2, 2023, at 3:07 AM, Richard Biener <rguent...@suse.de> wrote:
>
> On Wed, 1 Feb 2023, Qing Zhao wrote:
>
>>
>>
>>> On Feb 1, 2023, at 6:41 AM, Richard Biener <rguent...@suse.de> wrote:
>>>
>>> On Tue, 31 Jan 2023, Qing Zhao wrote:
>>>
>>>> GCC extension accepts the case when a struct with a flexible array member
>>>> is embedded into another struct (possibly recursively).
>>>> __builtin_object_size should treat such struct as flexible size per
>>>> -fstrict-flex-arrays.
>>>>
>>>> PR tree-optimization/101832
>>>>
>>>> gcc/ChangeLog:
>>>>
>>>> PR tree-optimization/101832
>>>> * tree-object-size.cc (flexible_size_type_p): New function.
>>>> (addr_object_size): Handle structure/union type when it has
>>>> flexible size.
>>>>
>>>> gcc/testsuite/ChangeLog:
>>>>
>>>> PR tree-optimization/101832
>>>> * gcc.dg/builtin-object-size-pr101832-2.c: New test.
>>>> * gcc.dg/builtin-object-size-pr101832-3.c: New test.
>>>> * gcc.dg/builtin-object-size-pr101832-4.c: New test.
>>>> * gcc.dg/builtin-object-size-pr101832.c: New test.
>>>> ---
>>>> .../gcc.dg/builtin-object-size-pr101832-2.c | 135 ++++++++++++++++++
>>>> .../gcc.dg/builtin-object-size-pr101832-3.c | 135 ++++++++++++++++++
>>>> .../gcc.dg/builtin-object-size-pr101832-4.c | 135 ++++++++++++++++++
>>>> .../gcc.dg/builtin-object-size-pr101832.c | 119 +++++++++++++++
>>>> gcc/tree-object-size.cc | 115 +++++++++++----
>>>> 5 files changed, 611 insertions(+), 28 deletions(-)
>>>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>>>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>>>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>>>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>>>>
>>>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>>>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>>>> new file mode 100644
>>>> index 00000000000..f38babc5415
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>>>> @@ -0,0 +1,135 @@
>>>> +/* PR 101832:
>>>> + GCC extension accepts the case when a struct with a flexible array
>>>> member
>>>> + is embedded into another struct (possibly recursively).
>>>> + __builtin_object_size will treat such struct as flexible size per
>>>> + -fstrict-flex-arrays. */
>>>> +/* { dg-do run } */
>>>> +/* { dg-options "-O2 -fstrict-flex-arrays=1" } */
>>>> +
>>>> +#include <stdio.h>
>>>> +
>>>> +unsigned n_fails = 0;
>>>> +
>>>> +#define expect(p, _v) do { \
>>>> + size_t v = _v; \
>>>> + if (p == v) \
>>>> + printf("ok: %s == %zd\n", #p, p); \
>>>> + else {\
>>>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>>>> + n_fails++; \
>>>> + } \
>>>> +} while (0);
>>>> +
>>>> +struct A {
>>>> + int n;
>>>> + char data[];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B {
>>>> + int m;
>>>> + struct A a;
>>>> +};
>>>> +
>>>> +struct C {
>>>> + int q;
>>>> + struct B b;
>>>> +};
>>>> +
>>>> +struct A0 {
>>>> + int n;
>>>> + char data[0];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B0 {
>>>> + int m;
>>>> + struct A0 a;
>>>> +};
>>>> +
>>>> +struct C0 {
>>>> + int q;
>>>> + struct B0 b;
>>>> +};
>>>> +
>>>> +struct A1 {
>>>> + int n;
>>>> + char data[1];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B1 {
>>>> + int m;
>>>> + struct A1 a;
>>>> +};
>>>> +
>>>> +struct C1 {
>>>> + int q;
>>>> + struct B1 b;
>>>> +};
>>>> +
>>>> +struct An {
>>>> + int n;
>>>> + char data[8];/* Content following header */
>>>> +};
>>>> +
>>>> +struct Bn {
>>>> + int m;
>>>> + struct An a;
>>>> +};
>>>> +
>>>> +struct Cn {
>>>> + int q;
>>>> + struct Bn b;
>>>> +};
>>>> +
>>>> +volatile void *magic1, *magic2;
>>>> +
>>>> +int main(int argc, char *argv[])
>>>> +{
>>>> + struct B *outer;
>>>> + struct C *outest;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer = (void *)magic1;
>>>> + outest = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>>>> +
>>>> + struct B0 *outer0;
>>>> + struct C0 *outest0;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer0 = (void *)magic1;
>>>> + outest0 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer0->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest0->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest0->b.a, 1), -1);
>>>> +
>>>> + struct B1 *outer1;
>>>> + struct C1 *outest1;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer1 = (void *)magic1;
>>>> + outest1 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer1->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest1->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest1->b.a, 1), -1);
>>>> +
>>>> + struct Bn *outern;
>>>> + struct Cn *outestn;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outern = (void *)magic1;
>>>> + outestn = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a));
>>>> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b));
>>>> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a));
>>>> +
>>>> + if (n_fails > 0)
>>>> + __builtin_abort ();
>>>> +
>>>> + return 0;
>>>> +}
>>>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>>>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>>>> new file mode 100644
>>>> index 00000000000..aaae99b8d67
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>>>> @@ -0,0 +1,135 @@
>>>> +/* PR 101832:
>>>> + GCC extension accepts the case when a struct with a flexible array
>>>> member
>>>> + is embedded into another struct (possibly recursively).
>>>> + __builtin_object_size will treat such struct as flexible size per
>>>> + -fstrict-flex-arrays. */
>>>> +/* { dg-do run } */
>>>> +/* { dg-options "-O2 -fstrict-flex-arrays=2" } */
>>>> +
>>>> +#include <stdio.h>
>>>> +
>>>> +unsigned n_fails = 0;
>>>> +
>>>> +#define expect(p, _v) do { \
>>>> + size_t v = _v; \
>>>> + if (p == v) \
>>>> + printf("ok: %s == %zd\n", #p, p); \
>>>> + else {\
>>>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>>>> + n_fails++; \
>>>> + } \
>>>> +} while (0);
>>>> +
>>>> +struct A {
>>>> + int n;
>>>> + char data[];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B {
>>>> + int m;
>>>> + struct A a;
>>>> +};
>>>> +
>>>> +struct C {
>>>> + int q;
>>>> + struct B b;
>>>> +};
>>>> +
>>>> +struct A0 {
>>>> + int n;
>>>> + char data[0];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B0 {
>>>> + int m;
>>>> + struct A0 a;
>>>> +};
>>>> +
>>>> +struct C0 {
>>>> + int q;
>>>> + struct B0 b;
>>>> +};
>>>> +
>>>> +struct A1 {
>>>> + int n;
>>>> + char data[1];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B1 {
>>>> + int m;
>>>> + struct A1 a;
>>>> +};
>>>> +
>>>> +struct C1 {
>>>> + int q;
>>>> + struct B1 b;
>>>> +};
>>>> +
>>>> +struct An {
>>>> + int n;
>>>> + char data[8];/* Content following header */
>>>> +};
>>>> +
>>>> +struct Bn {
>>>> + int m;
>>>> + struct An a;
>>>> +};
>>>> +
>>>> +struct Cn {
>>>> + int q;
>>>> + struct Bn b;
>>>> +};
>>>> +
>>>> +volatile void *magic1, *magic2;
>>>> +
>>>> +int main(int argc, char *argv[])
>>>> +{
>>>> + struct B *outer;
>>>> + struct C *outest;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer = (void *)magic1;
>>>> + outest = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>>>> +
>>>> + struct B0 *outer0;
>>>> + struct C0 *outest0;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer0 = (void *)magic1;
>>>> + outest0 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer0->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest0->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest0->b.a, 1), -1);
>>>> +
>>>> + struct B1 *outer1;
>>>> + struct C1 *outest1;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer1 = (void *)magic1;
>>>> + outest1 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer1->a, 1), sizeof(outer1->a));
>>>> + expect(__builtin_object_size(&outest1->b, 1), sizeof(outest1->b));
>>>> + expect(__builtin_object_size(&outest1->b.a, 1), sizeof(outest1->b.a));
>>>> +
>>>> + struct Bn *outern;
>>>> + struct Cn *outestn;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outern = (void *)magic1;
>>>> + outestn = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a));
>>>> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b));
>>>> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a));
>>>> +
>>>> + if (n_fails > 0)
>>>> + __builtin_abort ();
>>>> +
>>>> + return 0;
>>>> +}
>>>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>>>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>>>> new file mode 100644
>>>> index 00000000000..424264e2acd
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>>>> @@ -0,0 +1,135 @@
>>>> +/* PR 101832:
>>>> + GCC extension accepts the case when a struct with a flexible array
>>>> member
>>>> + is embedded into another struct (possibly recursively).
>>>> + __builtin_object_size will treat such struct as flexible size per
>>>> + -fstrict-flex-arrays. */
>>>> +/* { dg-do run } */
>>>> +/* { dg-options "-O2 -fstrict-flex-arrays=3" } */
>>>> +
>>>> +#include <stdio.h>
>>>> +
>>>> +unsigned n_fails = 0;
>>>> +
>>>> +#define expect(p, _v) do { \
>>>> + size_t v = _v; \
>>>> + if (p == v) \
>>>> + printf("ok: %s == %zd\n", #p, p); \
>>>> + else {\
>>>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>>>> + n_fails++; \
>>>> + } \
>>>> +} while (0);
>>>> +
>>>> +struct A {
>>>> + int n;
>>>> + char data[];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B {
>>>> + int m;
>>>> + struct A a;
>>>> +};
>>>> +
>>>> +struct C {
>>>> + int q;
>>>> + struct B b;
>>>> +};
>>>> +
>>>> +struct A0 {
>>>> + int n;
>>>> + char data[0];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B0 {
>>>> + int m;
>>>> + struct A0 a;
>>>> +};
>>>> +
>>>> +struct C0 {
>>>> + int q;
>>>> + struct B0 b;
>>>> +};
>>>> +
>>>> +struct A1 {
>>>> + int n;
>>>> + char data[1];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B1 {
>>>> + int m;
>>>> + struct A1 a;
>>>> +};
>>>> +
>>>> +struct C1 {
>>>> + int q;
>>>> + struct B1 b;
>>>> +};
>>>> +
>>>> +struct An {
>>>> + int n;
>>>> + char data[8];/* Content following header */
>>>> +};
>>>> +
>>>> +struct Bn {
>>>> + int m;
>>>> + struct An a;
>>>> +};
>>>> +
>>>> +struct Cn {
>>>> + int q;
>>>> + struct Bn b;
>>>> +};
>>>> +
>>>> +volatile void *magic1, *magic2;
>>>> +
>>>> +int main(int argc, char *argv[])
>>>> +{
>>>> + struct B *outer;
>>>> + struct C *outest;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer = (void *)magic1;
>>>> + outest = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>>>> +
>>>> + struct B0 *outer0;
>>>> + struct C0 *outest0;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer0 = (void *)magic1;
>>>> + outest0 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer0->a, 1), sizeof(outer0->a));
>>>> + expect(__builtin_object_size(&outest0->b, 1), sizeof(outest0->b));
>>>> + expect(__builtin_object_size(&outest0->b.a, 1), sizeof(outest0->b.a));
>>>> +
>>>> + struct B1 *outer1;
>>>> + struct C1 *outest1;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outer1 = (void *)magic1;
>>>> + outest1 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer1->a, 1), sizeof(outer1->a));
>>>> + expect(__builtin_object_size(&outest1->b, 1), sizeof(outest1->b));
>>>> + expect(__builtin_object_size(&outest1->b.a, 1), sizeof(outest1->b.a));
>>>> +
>>>> + struct Bn *outern;
>>>> + struct Cn *outestn;
>>>> +
>>>> + /* Make sure optimization can't find some other object size. */
>>>> + outern = (void *)magic1;
>>>> + outestn = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a));
>>>> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b));
>>>> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a));
>>>> +
>>>> + if (n_fails > 0)
>>>> + __builtin_abort ();
>>>> +
>>>> + return 0;
>>>> +}
>>>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>>>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>>>> new file mode 100644
>>>> index 00000000000..8ed6980edf0
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>>>> @@ -0,0 +1,119 @@
>>>> +/* PR 101832:
>>>> + GCC extension accepts the case when a struct with a flexible array
>>>> member
>>>> + is embedded into another struct (possibly recursively).
>>>> + __builtin_object_size will treat such struct as flexible size per
>>>> + -fstrict-flex-arrays. */
>>>> +/* { dg-do run } */
>>>> +/* { dg-options "-O2" } */
>>>> +
>>>> +#include <stdio.h>
>>>> +
>>>> +unsigned n_fails = 0;
>>>> +
>>>> +#define expect(p, _v) do { \
>>>> + size_t v = _v; \
>>>> + if (p == v) \
>>>> + printf("ok: %s == %zd\n", #p, p); \
>>>> + else {\
>>>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>>>> + n_fails++; \
>>>> + } \
>>>> +} while (0);
>>>> +
>>>> +struct A {
>>>> + int n;
>>>> + char data[];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B {
>>>> + int m;
>>>> + struct A a;
>>>> +};
>>>> +
>>>> +struct C {
>>>> + int q;
>>>> + struct B b;
>>>> +};
>>>> +
>>>> +struct A0 {
>>>> + int n;
>>>> + char data[0];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B0 {
>>>> + int m;
>>>> + struct A0 a;
>>>> +};
>>>> +
>>>> +struct C0 {
>>>> + int q;
>>>> + struct B0 b;
>>>> +};
>>>> +
>>>> +struct A1 {
>>>> + int n;
>>>> + char data[1];/* Content following header */
>>>> +};
>>>> +
>>>> +struct B1 {
>>>> + int m;
>>>> + struct A1 a;
>>>> +};
>>>> +
>>>> +struct C1 {
>>>> + int q;
>>>> + struct B1 b;
>>>> +};
>>>> +
>>>> +struct An {
>>>> + int n;
>>>> + char data[8];/* Content following header */
>>>> +};
>>>> +
>>>> +struct Bn {
>>>> + int m;
>>>> + struct An a;
>>>> +};
>>>> +
>>>> +struct Cn {
>>>> + int q;
>>>> + struct Bn b;
>>>> +};
>>>> +
>>>> +volatile void *magic1, *magic2;
>>>> +
>>>> +int main(int argc, char *argv[])
>>>> +{
>>>> + struct B *outer = (void *)magic1;
>>>> + struct C *outest = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>>>> +
>>>> + struct B0 *outer0 = (void *)magic1;
>>>> + struct C0 *outest0 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer0->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest0->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest0->b.a, 1), -1);
>>>> +
>>>> + struct B1 *outer1 = (void *)magic1;
>>>> + struct C1 *outest1 = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outer1->a, 1), -1);
>>>> + expect(__builtin_object_size(&outest1->b, 1), -1);
>>>> + expect(__builtin_object_size(&outest1->b.a, 1), -1);
>>>> +
>>>> + struct Bn *outern = (void *)magic1;
>>>> + struct Cn *outestn = (void *)magic2;
>>>> +
>>>> + expect(__builtin_object_size(&outern->a, 1), -1);
>>>> + expect(__builtin_object_size(&outestn->b, 1), -1);
>>>> + expect(__builtin_object_size(&outestn->b.a, 1), -1);
>>>> +
>>>> + if (n_fails > 0)
>>>> + __builtin_abort ();
>>>> +
>>>> + return 0;
>>>> +}
>>>> diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
>>>> index 9a936a91983..56b78ca2a8c 100644
>>>> --- a/gcc/tree-object-size.cc
>>>> +++ b/gcc/tree-object-size.cc
>>>> @@ -500,6 +500,42 @@ decl_init_size (tree decl, bool min)
>>>> return size;
>>>> }
>>>>
>>>> +/* Determine whether TYPE is a structure with a flexible array member
>>>> + per -fstrict-flex-array or a union containing such a structure
>>>> + (possibly recursively). */
>>>> +static bool
>>>> +flexible_size_type_p (const_tree type)
>>>> +{
>>>> + tree x = NULL_TREE;
>>>> + tree last = NULL_TREE;
>>>> + switch (TREE_CODE (type))
>>>> + {
>>>> + case RECORD_TYPE:
>>>> + for (x = TYPE_FIELDS (type); x != NULL_TREE; x = DECL_CHAIN (x))
>>>> + if (TREE_CODE (x) == FIELD_DECL)
>>>> + last = x;
>>>> + if (last == NULL_TREE)
>>>> + return false;
>>>> + if (TREE_CODE (TREE_TYPE (last)) == ARRAY_TYPE
>>>> + && !DECL_NOT_FLEXARRAY (last))
>>>> + return true;
>>>> + else if (TREE_CODE (TREE_TYPE (last)) == RECORD_TYPE
>>>> + || TREE_CODE (TREE_TYPE (last)) == UNION_TYPE)
>>>> + return flexible_size_type_p (TREE_TYPE (last));
>>>
>>> For types with many members this can become quite slow (IIRC we had
>>> bugs about similar walks of all fields in types), and this function
>>> looks like it's invoked multiple times on the same type per TU.
>>>
>>> In principle the property is fixed at the time we lay out a record
>>> type, so we might want to compute it at that time and record the
>>> result.
>>
>> You mean in FE?
>
> Yes, either in the frontend or in the middle-ends layout_type.
>
>> Yes, that?s better and cleaner.
>>
>> I will add one more field in the TYPE structure to record this information
>> and check this field during middle end.
>>
>> I had the same thought in the beginning, but not sure whether adding a
>> new field in IR is necessary or not, other places in middle end might
>> not use this new field.
>
> It might be interesting to search for other code walking all fields of
> a type to determine this or similar info.
There is one which is defined in tree.cc but only is referenced in c/c-decl.cc:
/* Determine whether TYPE is a structure with a flexible array member,
or a union containing such a structure (possibly recursively). */
flexible_array_type_p
However, this routine is a little different than the one I tried to add:
In the current routine “flexible_array_type_p”, only one level nesting in the
structure is accepted, multiple nesting in structure is not permitted.
So, my question is: shall we accept multiple nesting in structure? i.e.
struct A {
int n;
char data[];/* Content following header */
};
struct B {
int m;
struct A a;
};
struct C {
int q;
struct B b;
};
Qing
>
>> thanks.
>>
>> Qing
>>
>>>
>>>> + return false;
>>>> + case UNION_TYPE:
>>>> + for (x = TYPE_FIELDS (type); x != NULL_TREE; x = DECL_CHAIN (x))
>>>> + {
>>>> + if (TREE_CODE (x) == FIELD_DECL
>>>> + && flexible_array_type_p (TREE_TYPE (x)))
>>>> + return true;
>>>> + }
>>>> + return false;
>>>> + default:
>>>> + return false;
>>>> + }
>>>> +}
>>>> +
>>>> /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR.
>>>> OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
>>>> If unknown, return size_unknown (object_size_type). */
>>>> @@ -633,45 +669,68 @@ addr_object_size (struct object_size_info *osi,
>>>> const_tree ptr,
>>>> v = NULL_TREE;
>>>> break;
>>>> case COMPONENT_REF:
>>>> - if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE)
>>>> + /* When the ref is not to an array, a record or a union, it
>>>> + will not have flexible size, compute the object size
>>>> + directly. */
>>>> + if ((TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE)
>>>> + && (TREE_CODE (TREE_TYPE (v)) != RECORD_TYPE)
>>>> + && (TREE_CODE (TREE_TYPE (v)) != UNION_TYPE))
>>>> {
>>>> v = NULL_TREE;
>>>> break;
>>>> }
>>>> - is_flexible_array_mem_ref = array_ref_flexible_size_p (v);
>>>> - while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>>>> - if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> - != UNION_TYPE
>>>> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> - != QUAL_UNION_TYPE)
>>>> - break;
>>>> - else
>>>> - v = TREE_OPERAND (v, 0);
>>>> - if (TREE_CODE (v) == COMPONENT_REF
>>>> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> - == RECORD_TYPE)
>>>> + /* if the record or union does not have flexible size
>>>> + compute the object size directly. */
>>>> + if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE
>>>> + || TREE_CODE (TREE_TYPE (v)) == UNION_TYPE)
>>>> {
>>>> - /* compute object size only if v is not a
>>>> - flexible array member. */
>>>> - if (!is_flexible_array_mem_ref)
>>>> + if (!flexible_size_type_p (TREE_TYPE (v)))
>>>> {
>>>> v = NULL_TREE;
>>>> break;
>>>> }
>>>> - v = TREE_OPERAND (v, 0);
>>>> + else
>>>> + v = TREE_OPERAND (v, 0);
>>>> }
>>>> - while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>>>> - if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> - != UNION_TYPE
>>>> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> - != QUAL_UNION_TYPE)
>>>> - break;
>>>> - else
>>>> - v = TREE_OPERAND (v, 0);
>>>> - if (v != pt_var)
>>>> - v = NULL_TREE;
>>>> else
>>>> - v = pt_var;
>>>> + {
>>>> + /* Now the ref is to an array type. */
>>>> + is_flexible_array_mem_ref
>>>> + = array_ref_flexible_size_p (v);
>>>> + while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>>>> + if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> + != UNION_TYPE
>>>> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> + != QUAL_UNION_TYPE)
>>>> + break;
>>>> + else
>>>> + v = TREE_OPERAND (v, 0);
>>>> + if (TREE_CODE (v) == COMPONENT_REF
>>>> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> + == RECORD_TYPE)
>>>> + {
>>>> + /* compute object size only if v is not a
>>>> + flexible array member. */
>>>> + if (!is_flexible_array_mem_ref)
>>>> + {
>>>> + v = NULL_TREE;
>>>> + break;
>>>> + }
>>>> + v = TREE_OPERAND (v, 0);
>>>> + }
>>>> + while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>>>> + if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> + != UNION_TYPE
>>>> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>>>> + != QUAL_UNION_TYPE)
>>>> + break;
>>>> + else
>>>> + v = TREE_OPERAND (v, 0);
>>>> + if (v != pt_var)
>>>> + v = NULL_TREE;
>>>> + else
>>>> + v = pt_var;
>>>> + }
>>>> break;
>>>> default:
>>>> v = pt_var;
>>>>
>>>
>>> --
>>> Richard Biener <rguent...@suse.de>
>>> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
>>> Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
>>> HRB 36809 (AG Nuernberg)
>>
>>
>
> --
> Richard Biener <rguent...@suse.de>
> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
> Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
> HRB 36809 (AG Nuernberg)
