// { dg-do run } // { dg-options "-fno-strict-aliasing" } // Origin: Mark Mitchell /* Generally, the lowest bit of the ptr is used to indicate whether a ptr-to-mem-func points to a virtual or a non-virtual member function. However, some platforms use all bits to encode a function pointer. Such platforms use the lowest bit of the delta, that is shifted left by one bit. */ #if defined __MN10300__ || defined __SH5__ || defined __arm__ || defined __thumb__ || defined __mips__ || defined __aarch64__ #define ADJUST_PTRFN(func, virt) ((void (*)())(func)) #define ADJUST_DELTA(delta, virt) (((delta) << 1) + !!(virt)) #else #define ADJUST_PTRFN(func, virt) ((void (*)())((ptrdiff_t)(func) + !!(virt))) #define ADJUST_DELTA(delta, virt) (delta) #endif /* IA64 uses function descriptors instead of function pointers in its vtables, which means that we can't meaningfully compare them directly. */ #if defined __ia64__ #define CMP_PTRFN(A, B) (*(void **)(A) == *(void **)(B)) #define VPTE_SIZE (16) #else #define CMP_PTRFN(A, B) ((A) == (B)) #define VPTE_SIZE sizeof(void *) #endif #if defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100 // Check that pointers-to-member functions are represented correctly. #include struct S { int i; int j; }; // Because S does not have a VPTR, it will not be a primary base of T, // and will therefore end up at a nonzero offset. struct T : public S { void f () {} virtual void g () {} virtual void h () {} }; // Provide access to the raw function pointers. This is // mangling-dependent. extern "C" void _ZN1T1fEv (); extern "C" void _ZN1T1gEv (); extern "C" void _ZN1T1hEv (); // This structure is a C representation of a pointer-to-member. struct ptrmemfunc { void (*ptr) (); ptrdiff_t adj; }; typedef int S::*sdp; typedef void (S::*sp)(); typedef void (T::*tp)(); int main () { S s; T t; sp x; tp y; ptrmemfunc *xp = (ptrmemfunc *) &x; ptrmemfunc *yp = (ptrmemfunc *) &y; ptrdiff_t delta = ((char *) &t) - ((char*) (S*) (&t)); // Pointers-to-function-members should have the same size and // alignment as the PTRMEMFUNC type. if (sizeof (sp) != sizeof (ptrmemfunc)) return 1; if (__alignof__ (sp) != __alignof__ (ptrmemfunc)) return 2; // The NULL pointer-to-member should have a NULL first PTR field. x = 0; if (xp->ptr != 0) return 3; y = x; if (yp->ptr != 0) return 4; // A non-virtual function should have a pointer to the function. // There should be no adjustment for the `T' version, and an // appropriate adjustment for the `S' version. y = &T::f; if (! CMP_PTRFN (yp->ptr, ADJUST_PTRFN (&_ZN1T1fEv, 0))) return 5; if (yp->adj != ADJUST_DELTA (0, 0)) return 6; x = (sp) y; if (! CMP_PTRFN (xp->ptr, ADJUST_PTRFN (&_ZN1T1fEv, 0))) return 7; if (xp->adj != ADJUST_DELTA (delta, 0)) return 8; // For a virtual function, we should see the vtable offset, plus // one. `T::h' is in the second slot: the vtable pointer points to // the first virtual function. y = &T::h; if (yp->ptr != ADJUST_PTRFN (VPTE_SIZE, 1)) return 9; if (yp->adj != ADJUST_DELTA (0, 1)) return 10; x = (sp) y; if (xp->ptr != ADJUST_PTRFN (VPTE_SIZE, 1)) return 11; if (xp->adj != ADJUST_DELTA (delta, 1)) return 12; // Pointers-to-data-members should have the same size and alignment // as a ptrdiff_t. if (sizeof (sdp) != sizeof (ptrdiff_t)) return 13; if (__alignof__ (sdp) != __alignof__ (ptrdiff_t)) return 14; // The value of a pointer-to-data member should be the offset from // the start of the structure. sdp z = &S::j; if ((char *) &s.j - (char *) &s != *((ptrdiff_t *) &z)) return 15; z = 0; if (*((ptrdiff_t *) &z) != -1) return 16; } #else /* !(defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100) */ int main () { } #endif /* !(defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100) */