gh-111389: expose _PyHASH_INF/BITS/MODULUS/IMAG macros as public

Doc/library/stdtypes.rst

@@ -723,7 +723,8 @@ made available to Python as the :attr:`modulus` attribute of
 .. impl-detail::
 
    Currently, the prime used is ``P = 2**31 - 1`` on machines with 32-bit C
-   longs and ``P = 2**61 - 1`` on machines with 64-bit C longs.
+   longs and ``P = 2**61 - 1`` on machines with 64-bit C longs.  The exponent
+   of this Mersenne prime is available as ``_PyHASH_BITS`` macro.
 
 Here are the rules in detail:
 

Doc/library/sys.rst

@@ -1022,19 +1022,22 @@ always available.
 
    .. attribute:: hash_info.modulus
 
-      The prime modulus P used for numeric hash scheme
+      The prime modulus P used for numeric hash scheme.  Available also as
+      ``_PyHASH_MODULUS`` macro.
 
    .. attribute:: hash_info.inf
 
-      The hash value returned for a positive infinity
+      The hash value returned for a positive infinity.  Available also as
+      ``_PyHASH_INF`` macro.
 
    .. attribute:: hash_info.nan
 
       (This attribute is no longer used)
 
    .. attribute:: hash_info.imag
 
-      The multiplier used for the imaginary part of a complex number
+      The multiplier used for the imaginary part of a complex number.
+      Available also as ``_PyHASH_IMAG`` macro.
 
    .. attribute:: hash_info.algorithm
 

Include/internal/pycore_pyhash.h

@@ -17,23 +17,6 @@ extern Py_hash_t _Py_HashPointerRaw(const void*);
 // Export for '_datetime' shared extension
 PyAPI_FUNC(Py_hash_t) _Py_HashBytes(const void*, Py_ssize_t);
 
-/* Prime multiplier used in string and various other hashes. */
-#define _PyHASH_MULTIPLIER 1000003UL  /* 0xf4243 */
-
-/* Parameters used for the numeric hash implementation.  See notes for
-   _Py_HashDouble in Python/pyhash.c.  Numeric hashes are based on
-   reduction modulo the prime 2**_PyHASH_BITS - 1. */
-
-#if SIZEOF_VOID_P >= 8
-#  define _PyHASH_BITS 61
-#else
-#  define _PyHASH_BITS 31
-#endif
-
-#define _PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1)
-#define _PyHASH_INF 314159
-#define _PyHASH_IMAG _PyHASH_MULTIPLIER
-
 /* Hash secret
  *
  * memory layout on 64 bit systems

Include/pyhash.h

@@ -16,6 +16,22 @@ typedef struct {
 PyAPI_FUNC(PyHash_FuncDef*) PyHash_GetFuncDef(void);
 #endif
 
+/* Prime multiplier used in string and various other hashes. */
+#define _PyHASH_MULTIPLIER 1000003UL  /* 0xf4243 */
+
+/* Parameters used for the numeric hash implementation.  See notes for
+   _Py_HashDouble in Python/pyhash.c.  Numeric hashes are based on
+   reduction modulo the prime 2**_PyHASH_BITS - 1. */
+
+#if SIZEOF_VOID_P >= 8
+#  define _PyHASH_BITS 61
+#else
+#  define _PyHASH_BITS 31
+#endif
+
+#define _PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1)
+#define _PyHASH_INF 314159
+#define _PyHASH_IMAG _PyHASH_MULTIPLIER
 
 /* Cutoff for small string DJBX33A optimization in range [1, cutoff).
  *