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// { dg-options "-Warray-bounds" }
// { dg-do compile }
// Test case exercising pr c/67882 - surprising offsetof result
// on an invalid array member without diagnostic.
typedef struct A1 {
char a1[1];
char c;
} A1;
typedef struct A1_x_2 {
char a1[1];
char a[][2];
} A1_x_2;
typedef struct A1_1_x {
char a1_1[1][1];
char a[];
} A1_1_x;
typedef struct Ax_2_3 {
int i;
char a_x_2_3[][2][3];
} Ax_2_3;
typedef struct A1_1 {
char a1_1[1][1];
char c;
} A1_1;
typedef struct B {
A1_1 a2_3[2][3];
char a1_1[3][5];
char a[];
} B;
// Structures with members that contain flexible array members are
// an extension accepted by GCC.
typedef struct C {
A1_1_x a5_7 [5][7];
int a;
} C;
// Structs with a "fake" flexible array member (a GCC extension).
typedef struct FA0 {
int i;
char a0 [0];
} FA0;
typedef struct FA1 {
int i;
char a1 [1];
} FA1;
typedef struct FA3 {
int i;
char a3 [3];
} FA3;
// A "fake" multidimensional flexible array member.
typedef struct FA5_7 {
int i;
char a5_7 [5][7];
} FA5_7;
static void test (void)
{
// Verify that offsetof references to array elements past the end of
// the array member are diagnosed. As an extension, permit references
// to the element just past-the-end of the array.
int a[] = {
__builtin_offsetof (A1, a1), // valid
__builtin_offsetof (A1, a1 [0]), // valid
// The following expression is valid because it forms the equivalent
// of an address pointing just past the last element of the array.
__builtin_offsetof (A1, a1 [1]), // valid
__builtin_offsetof (A1, a1 [2]), // { dg-warning "index" }
__builtin_offsetof (A1_x_2, a1), // valid
__builtin_offsetof (A1_x_2, a1 [0]), // valid
__builtin_offsetof (A1_x_2, a1 [1]), // valid
__builtin_offsetof (A1_x_2, a1 [2]), // { dg-warning "index" }
__builtin_offsetof (A1_x_2, a), // valid
__builtin_offsetof (A1_x_2, a [0]), // valid
__builtin_offsetof (A1_x_2, a [1]), // valid
__builtin_offsetof (A1_x_2, a [99]), // valid
__builtin_offsetof (A1_x_2, a), // valid
__builtin_offsetof (A1_x_2, a [0][0]), // valid
__builtin_offsetof (A1_x_2, a [0][1]), // valid
// The following expression is valid because it forms the equivalent
// of an address pointing just past the last element of the first
// array.
__builtin_offsetof (A1_x_2, a [0][2]), // valid
// Unlike the case above, this is invalid since it refers to an element
// past one one just-past-the-end in A[][2].
__builtin_offsetof (A1_x_2, a [0][3]), // { dg-warning "index" }
__builtin_offsetof (A1_x_2, a [1][0]), // valid
__builtin_offsetof (A1_x_2, a [1][1]), // valid
__builtin_offsetof (A1_x_2, a [1][2]), // valid
__builtin_offsetof (A1_x_2, a [99][0]), // valid
__builtin_offsetof (A1_x_2, a [99][1]), // valid
__builtin_offsetof (A1_x_2, a [99][2]), // valid
__builtin_offsetof (A1_1_x, a), // valid
__builtin_offsetof (A1_1_x, a [0]), // valid
__builtin_offsetof (A1_1_x, a [1]), // valid
__builtin_offsetof (A1_1_x, a [99]), // valid
__builtin_offsetof (A1_1_x, a1_1 [0][0]), // valid
__builtin_offsetof (A1_1_x, a1_1 [0][1]), // valid
__builtin_offsetof (A1_1_x, a1_1 [0][2]), // { dg-warning "index" }
__builtin_offsetof (A1_1_x, a1_1 [1][0]), // { dg-warning "index" }
__builtin_offsetof (A1_1_x, a1_1 [1][1]), // { dg-warning "index" }
__builtin_offsetof (Ax_2_3, a_x_2_3 [0][1][3]), // valid
__builtin_offsetof (Ax_2_3, a_x_2_3 [0][1][4]), // { dg-warning "index" }
__builtin_offsetof (Ax_2_3, a_x_2_3 [0][2]), // valid
__builtin_offsetof (Ax_2_3, a_x_2_3 [0][2][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [0][0].c), // valid
__builtin_offsetof (B, a2_3 [0][0].a1_1 [0][0]), // valid
__builtin_offsetof (B, a2_3 [1][3]), // valid
__builtin_offsetof (B, a2_3 [1][4]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [0][0].a1_1 [0][1]), // valid
__builtin_offsetof (B, a2_3 [0][0].a1_1 [0][2]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [0][0].a1_1 [1][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [0][0].a1_1 [1][1]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][2].a1_1 [0][0]), // valid
// Forming an offset to the just-past-end element is valid.
__builtin_offsetof (B, a2_3 [1][2].a1_1 [0][1]), // valid
__builtin_offsetof (B, a2_3 [1][2].a1_1 [1][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][2].a1_1 [1][1]), // { dg-warning "index" }
// Forming an offset to the just-past-end element is valid.
__builtin_offsetof (B, a2_3 [1][3]), // valid
// ...but these are diagnosed because they dereference a just-past-the-end
// element.
__builtin_offsetof (B, a2_3 [1][3].a1_1 [0][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][3].a1_1 [0][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][3].a1_1 [0][1]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][3].a1_1 [1][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][3].a1_1 [1][1]), // { dg-warning "index" }
// Analogous to the case above, these are both diagnosed because they
// dereference just-past-the-end elements of the a2_3 array.
__builtin_offsetof (B, a2_3 [1][3].c), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [1][3].c), // { dg-warning "index" }
// The following are all invalid because of the reference to a2_3[2].
__builtin_offsetof (B, a2_3 [2][0].a1_1 [0][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [2][0].a1_1 [0][1]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [2][0].a1_1 [1][0]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [2][0].a1_1 [1][1]), // { dg-warning "index" }
__builtin_offsetof (B, a2_3 [2][0].c), // { dg-warning "index" }
__builtin_offsetof (C, a5_7 [4][6]),
__builtin_offsetof (C, a5_7 [4][6].a),
__builtin_offsetof (C, a5_7 [4][6].a [0]),
__builtin_offsetof (C, a5_7 [4][6].a [99]),
__builtin_offsetof (C, a5_7 [4][7]), // valid
// Diagnose the following even though the object whose offset is
// computed is a flexible array member.
__builtin_offsetof (C, a5_7 [4][7].a), // { dg-warning "index" }
__builtin_offsetof (C, a5_7 [4][7].a [0]), // { dg-warning "index" }
__builtin_offsetof (C, a5_7 [4][7].a [99]), // { dg-warning "index" }
// Verify that no diagnostic is issued for offsetof expressions
// involving structs where the array has a rank of 1 and is the last
// member (e.g., those are treated as flexible array members).
__builtin_offsetof (FA0, a0 [0]),
__builtin_offsetof (FA0, a0 [1]),
__builtin_offsetof (FA0, a0 [99]),
__builtin_offsetof (FA1, a1 [0]),
__builtin_offsetof (FA1, a1 [1]),
__builtin_offsetof (FA1, a1 [99]),
__builtin_offsetof (FA3, a3 [0]),
__builtin_offsetof (FA3, a3 [3]),
__builtin_offsetof (FA3, a3 [99]),
__builtin_offsetof (FA5_7, a5_7 [0][0]),
// Unlike one-dimensional arrays, verify that out-of-bounds references
// to "fake" flexible arrays with rank of 2 and greater are diagnosed.
// The following are valid because they compute the offset of just past
// the end of each of the a5_7[0] and a5_7[1] arrays.
__builtin_offsetof (FA5_7, a5_7 [0][7]), // valid
__builtin_offsetof (FA5_7, a5_7 [1][7]), // valid
// The following two are accepted as an extesion (because a5_7 is
// treated as a flexible array member).
__builtin_offsetof (FA5_7, a5_7 [5][0]), // extension
__builtin_offsetof (FA5_7, a5_7 [5][7]), // extension
// The following are invalid since in both cases they denote an element
// that's beyond just-past-the-end of the array.
__builtin_offsetof (FA5_7, a5_7 [0][8]), // { dg-warning "index" }
__builtin_offsetof (FA5_7, a5_7 [6][8]) // { dg-warning "index" }
};
(void)&a;
}
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