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gtypes: Rework checked arithmetic handling

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Rather than using the fixed-type compiler builtins
(`__builtin_uadd_overflow()`, etc.), use the generic versions
(`__builtin_add_overflow()`). This avoids issues with matching the
definition of GLib types (such as `guint` and particularly `gsize`) to
basic C types (`int`, `long`, `long long`), as the mapping can vary
between platforms.

See https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html

Adjust the fallback inline functions similarly.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>

Fixes: #2523
This commit is contained in:
Philip Withnall 2021-11-17 11:52:21 +00:00
parent e7e2949f31
commit bc04b57eed
1 changed files with 36 additions and 30 deletions
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66
glib/gtypes.h
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@ -424,56 +424,62 @@ typedef const gchar * (*GTranslateFunc) (const gchar *str,
/* https://bugzilla.gnome.org/show_bug.cgi?id=769104 */
#if __GNUC__ >= 5 && !defined(__INTEL_COMPILER)
#define _GLIB_HAVE_BUILTIN_OVERFLOW_CHECKS
#elif g_macro__has_builtin(__builtin_uadd_overflow)
#elif g_macro__has_builtin(__builtin_add_overflow)
#define _GLIB_HAVE_BUILTIN_OVERFLOW_CHECKS
#endif
#endif
#ifdef _GLIB_HAVE_BUILTIN_OVERFLOW_CHECKS
#define g_uint_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_U32(dest, a, b)
(!__builtin_add_overflow(a, b, dest))
#define g_uint_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_U32(dest, a, b)
(!__builtin_mul_overflow(a, b, dest))
#define g_uint64_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_U64(dest, a, b)
(!__builtin_add_overflow(a, b, dest))
#define g_uint64_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_U64(dest, a, b)
(!__builtin_mul_overflow(a, b, dest))
#if GLIB_SIZEOF_SIZE_T == 8
#define g_size_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_U64(dest, a, b)
(!__builtin_add_overflow(a, b, dest))
#define g_size_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_U64(dest, a, b)
#else
#define g_size_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_U32(dest, a, b)
#define g_size_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_U32(dest, a, b)
#endif
(!__builtin_mul_overflow(a, b, dest))
#else /* !_GLIB_HAVE_BUILTIN_OVERFLOW_CHECKS */
/* The names of the following inlines are private. Use the macro
* definitions above.
*/
#ifdef _GLIB_HAVE_BUILTIN_OVERFLOW_CHECKS
static inline gboolean _GLIB_CHECKED_ADD_U32 (guint32 *dest, guint32 a, guint32 b) {
return !__builtin_uadd_overflow(a, b, dest); }
static inline gboolean _GLIB_CHECKED_MUL_U32 (guint32 *dest, guint32 a, guint32 b) {
return !__builtin_umul_overflow(a, b, dest); }
static inline gboolean _GLIB_CHECKED_ADD_U64 (guint64 *dest, guint64 a, guint64 b) {
G_STATIC_ASSERT(sizeof (unsigned long long) == sizeof (guint64));
return !__builtin_uaddll_overflow(a, b, (unsigned long long *) dest); }
static inline gboolean _GLIB_CHECKED_MUL_U64 (guint64 *dest, guint64 a, guint64 b) {
return !__builtin_umulll_overflow(a, b, (unsigned long long *) dest); }
#else
static inline gboolean _GLIB_CHECKED_ADD_U32 (guint32 *dest, guint32 a, guint32 b) {
static inline gboolean _GLIB_CHECKED_ADD_UINT (guint *dest, guint a, guint b) {
*dest = a + b; return *dest >= a; }
static inline gboolean _GLIB_CHECKED_MUL_U32 (guint32 *dest, guint32 a, guint32 b) {
static inline gboolean _GLIB_CHECKED_MUL_UINT (guint *dest, guint a, guint b) {
*dest = a * b; return !a || *dest / a == b; }
static inline gboolean _GLIB_CHECKED_ADD_U64 (guint64 *dest, guint64 a, guint64 b) {
static inline gboolean _GLIB_CHECKED_ADD_UINT64 (guint64 *dest, guint64 a, guint64 b) {
*dest = a + b; return *dest >= a; }
static inline gboolean _GLIB_CHECKED_MUL_U64 (guint64 *dest, guint64 a, guint64 b) {
static inline gboolean _GLIB_CHECKED_MUL_UINT64 (guint64 *dest, guint64 a, guint64 b) {
*dest = a * b; return !a || *dest / a == b; }
#endif
static inline gboolean _GLIB_CHECKED_ADD_SIZE (gsize *dest, gsize a, gsize b) {
*dest = a + b; return *dest >= a; }
static inline gboolean _GLIB_CHECKED_MUL_SIZE (gsize *dest, gsize a, gsize b) {
*dest = a * b; return !a || *dest / a == b; }
#define g_uint_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_UINT(dest, a, b)
#define g_uint_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_UINT(dest, a, b)
#define g_uint64_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_UINT64(dest, a, b)
#define g_uint64_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_UINT64(dest, a, b)
#define g_size_checked_add(dest, a, b) \
_GLIB_CHECKED_ADD_SIZE(dest, a, b)
#define g_size_checked_mul(dest, a, b) \
_GLIB_CHECKED_MUL_SIZE(dest, a, b)
#endif /* !_GLIB_HAVE_BUILTIN_OVERFLOW_CHECKS */
/* IEEE Standard 754 Single Precision Storage Format (gfloat):
*