diff options
Diffstat (limited to 'src/lisp.h')
| -rw-r--r-- | src/lisp.h | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/src/lisp.h b/src/lisp.h index 5a07bda3592..79c96e11da8 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -35,6 +35,7 @@ along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */ #endif #include <attribute.h> +#include <count-leading-zeros.h> #include <intprops.h> #include <verify.h> @@ -3909,6 +3910,20 @@ integer_to_uintmax (Lisp_Object num, uintmax_t *n) } } +/* Return floor (log2 (N)) as an int, where 0 < N <= ULLONG_MAX. */ +#if (201112 <= __STDC_VERSION__ && INT_MAX <= UINT_MAX \ + && LONG_MAX <= ULONG_MAX && LLONG_MAX <= ULLONG_MAX) +# define elogb(n) \ + _Generic (+(n), \ + int: UINT_WIDTH - 1 - count_leading_zeros (n), \ + unsigned int: UINT_WIDTH - 1 - count_leading_zeros (n), \ + long: ULONG_WIDTH - 1 - count_leading_zeros_l (n), \ + unsigned long: ULONG_WIDTH - 1 - count_leading_zeros_l (n), \ + default: ULLONG_WIDTH - 1 - count_leading_zeros_ll (n)) +#else +# define elogb(n) (ULLONG_WIDTH - 1 - count_leading_zeros_ll (n)) +#endif + /* A modification count. These are wide enough, and incremented rarely enough, so that they should never overflow a 60-bit counter in practice, and the code below assumes this so a compiler can @@ -3918,11 +3933,12 @@ typedef intmax_t modiff_count; INLINE modiff_count modiff_incr (modiff_count *a, ptrdiff_t len) { - modiff_count a0 = *a; int incr = len ? 1 : 0; + modiff_count a0 = *a; /* Increase the counter more for a large modification and less for a small modification. Increase it logarithmically to avoid increasing it too much. */ - while (len >>= 1) incr++; + verify (PTRDIFF_MAX <= ULLONG_MAX); + int incr = len == 0 ? 1 : elogb (len) + 1; bool modiff_overflow = INT_ADD_WRAPV (a0, incr, a); eassert (!modiff_overflow && *a >> 30 >> 30 == 0); return a0; @@ -5421,6 +5437,14 @@ safe_free_unbind_to (specpdl_ref count, specpdl_ref sa_count, Lisp_Object val) return unbind_to (count, val); } +/* Work around GCC bug 109577 + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109577 + which causes GCC to mistakenly complain about the + memory allocation in SAFE_ALLOCA_LISP_EXTRA. */ +#if GNUC_PREREQ (13, 0, 0) +# pragma GCC diagnostic ignored "-Wanalyzer-allocation-size" +#endif + /* Set BUF to point to an allocated array of NELT Lisp_Objects, immediately followed by EXTRA spare bytes. */ |