Use array_at_struct_end_p to determine whether the trailing array
of a structure is flexible array member in __builtin_object_size.
gcc/ChangeLog:
PR tree-optimization/101836
* tree-object-size.cc (addr_object_size): Use array_at_struct_end_p
to determine a flexible array member reference.
gcc/testsuite/ChangeLog:
PR tree-optimization/101836
* gcc.dg/pr101836.c: New test.
* gcc.dg/pr101836_1.c: New test.
* gcc.dg/pr101836_2.c: New test.
* gcc.dg/pr101836_3.c: New test.
* gcc.dg/pr101836_4.c: New test.
* gcc.dg/pr101836_5.c: New test.
* gcc.dg/strict-flex-array-2.c: New test.
* gcc.dg/strict-flex-array-3.c: New test.
---
gcc/testsuite/gcc.dg/pr101836.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr101836_1.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr101836_2.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr101836_3.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr101836_4.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr101836_5.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/strict-flex-array-2.c | 60 ++++++++++++++++++++++
gcc/testsuite/gcc.dg/strict-flex-array-3.c | 60 ++++++++++++++++++++++
gcc/tree-object-size.cc | 16 +++---
9 files changed, 487 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr101836.c
create mode 100644 gcc/testsuite/gcc.dg/pr101836_1.c
create mode 100644 gcc/testsuite/gcc.dg/pr101836_2.c
create mode 100644 gcc/testsuite/gcc.dg/pr101836_3.c
create mode 100644 gcc/testsuite/gcc.dg/pr101836_4.c
create mode 100644 gcc/testsuite/gcc.dg/pr101836_5.c
create mode 100644 gcc/testsuite/gcc.dg/strict-flex-array-2.c
create mode 100644 gcc/testsuite/gcc.dg/strict-flex-array-3.c
diff --git a/gcc/testsuite/gcc.dg/pr101836.c b/gcc/testsuite/gcc.dg/pr101836.c
new file mode 100644
index 000000000000..efad02cfe899
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101836.c
@@ -0,0 +1,60 @@
+/* -fstrict-flex-arrays is aliased with -ftrict-flex-arrays=3, which is the
+ strictest, only [] is treated as flexible array. */
+/* PR tree-optimization/101836 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4];
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1];
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0];
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), 16);
+ expect(__builtin_object_size(trailing_1->c, 1), 4);
+ expect(__builtin_object_size(trailing_0->c, 1), 0);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr101836_1.c
b/gcc/testsuite/gcc.dg/pr101836_1.c
new file mode 100644
index 000000000000..e2931ce1012e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101836_1.c
@@ -0,0 +1,60 @@
+/* -fstrict-flex-arrays=3 is the strictest, only [] is treated as
+ flexible array. */
+/* PR tree-optimization/101836 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays=3" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4];
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1];
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0];
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), 16);
+ expect(__builtin_object_size(trailing_1->c, 1), 4);
+ expect(__builtin_object_size(trailing_0->c, 1), 0);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr101836_2.c
b/gcc/testsuite/gcc.dg/pr101836_2.c
new file mode 100644
index 000000000000..78974187721f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101836_2.c
@@ -0,0 +1,60 @@
+/* When -fstrict-flex-arrays=2, only [] and [0] are treated as flexiable
+ arrays. */
+/* PR tree-optimization/101836 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays=2" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4];
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1];
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0];
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), 16);
+ expect(__builtin_object_size(trailing_1->c, 1), 4);
+ expect(__builtin_object_size(trailing_0->c, 1), -1);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr101836_3.c
b/gcc/testsuite/gcc.dg/pr101836_3.c
new file mode 100644
index 000000000000..0e69388e81fb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101836_3.c
@@ -0,0 +1,60 @@
+/* When -fstrict-flex-arrays=1, [], [0], and [1] are treated as flexible
+ arrays. */
+/* PR tree-optimization/101836 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays=1" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4];
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1];
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0];
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), 16);
+ expect(__builtin_object_size(trailing_1->c, 1), -1);
+ expect(__builtin_object_size(trailing_0->c, 1), -1);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr101836_4.c
b/gcc/testsuite/gcc.dg/pr101836_4.c
new file mode 100644
index 000000000000..e0025aa9a7b5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101836_4.c
@@ -0,0 +1,60 @@
+/* when -fstrict-flex-arrays=0, all trailing arrays are treated as
+ flexible arrays. */
+/* PR tree-optimization/101836 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays=0" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4];
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1];
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0];
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), -1);
+ expect(__builtin_object_size(trailing_1->c, 1), -1);
+ expect(__builtin_object_size(trailing_0->c, 1), -1);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr101836_5.c
b/gcc/testsuite/gcc.dg/pr101836_5.c
new file mode 100644
index 000000000000..0ad8bbf693ce
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101836_5.c
@@ -0,0 +1,60 @@
+/* -fno-strict-flex-arrays is aliased to -fstrict-flex-arrays=0,
+ all trailing arrays are treated as flexible array. */
+/* PR tree-optimization/101836 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-strict-flex-arrays" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4];
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1];
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0];
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), -1);
+ expect(__builtin_object_size(trailing_1->c, 1), -1);
+ expect(__builtin_object_size(trailing_0->c, 1), -1);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/strict-flex-array-2.c
b/gcc/testsuite/gcc.dg/strict-flex-array-2.c
new file mode 100644
index 000000000000..e474b9ec43fa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strict-flex-array-2.c
@@ -0,0 +1,60 @@
+/* test the combination of attribute strict_flex_arrays and option
+ -fstrict-flex-arrays: when both attribute and option specified,
+ attribute will have higher priority. */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays=3" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4] __attribute__ ((strict_flex_arrays (0)));
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1] __attribute__ ((strict_flex_arrays (1)));
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0] __attribute__ ((strict_flex_arrays (2)));
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), -1);
+ expect(__builtin_object_size(trailing_1->c, 1), -1);
+ expect(__builtin_object_size(trailing_0->c, 1), -1);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/strict-flex-array-3.c
b/gcc/testsuite/gcc.dg/strict-flex-array-3.c
new file mode 100644
index 000000000000..b45e7b32f6d1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strict-flex-array-3.c
@@ -0,0 +1,60 @@
+/* test the combination of attribute strict_flex_arrays and option
+ -fstrict-flex-arrays: when both attribute and option specified,
+ attribute will have higher priority. */
+/* { dg-do run } */
+/* { dg-options "-O2 -fstrict-flex-arrays=0" } */
+
+#include <stdio.h>
+
+#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); \
+ __builtin_abort (); \
+ } \
+} while (0);
+
+struct trailing_array_1 {
+ int a;
+ int b;
+ int c[4] __attribute__ ((strict_flex_arrays (1)));
+};
+
+struct trailing_array_2 {
+ int a;
+ int b;
+ int c[1] __attribute__ ((strict_flex_arrays (2)));
+};
+
+struct trailing_array_3 {
+ int a;
+ int b;
+ int c[0] __attribute__ ((strict_flex_arrays (3)));
+};
+struct trailing_array_4 {
+ int a;
+ int b;
+ int c[];
+};
+
+void __attribute__((__noinline__)) stuff(
+ struct trailing_array_1 *normal,
+ struct trailing_array_2 *trailing_1,
+ struct trailing_array_3 *trailing_0,
+ struct trailing_array_4 *trailing_flex)
+{
+ expect(__builtin_object_size(normal->c, 1), 16);
+ expect(__builtin_object_size(trailing_1->c, 1), 4);
+ expect(__builtin_object_size(trailing_0->c, 1), 0);
+ expect(__builtin_object_size(trailing_flex->c, 1), -1);
+}
+
+int main(int argc, char *argv[])
+{
+ stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]);
+
+ return 0;
+}
diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
index 4eb454a4a33b..1f04cb80fd0a 100644
--- a/gcc/tree-object-size.cc
+++ b/gcc/tree-object-size.cc
@@ -604,9 +604,9 @@ addr_object_size (struct object_size_info *osi, const_tree
ptr,
else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF)
{
tree v = var;
- /* For &X->fld, compute object size only if fld isn't the last
- field, as struct { int i; char c[1]; } is often used instead
- of flexible array member. */
+ /* For &X->fld, compute object size if fld isn't a flexible array
+ member. */
+ bool is_flexible_array_mem_ref = false;
while (v && v != pt_var)
switch (TREE_CODE (v))
{
@@ -633,6 +633,7 @@ addr_object_size (struct object_size_info *osi, const_tree
ptr,
v = NULL_TREE;
break;
}
+ is_flexible_array_mem_ref = array_at_struct_end_p (v);
while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
!= UNION_TYPE
@@ -645,12 +646,9 @@ addr_object_size (struct object_size_info *osi, const_tree
ptr,
&& TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
== RECORD_TYPE)
{
- tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1));
- for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain))
- if (TREE_CODE (fld_chain) == FIELD_DECL)
- break;
-
- if (fld_chain)
+ /* compute object size only if v is not a
+ flexible array member. */
+ if (!is_flexible_array_mem_ref)
{
v = NULL_TREE;
break;
--
2.31.1
