bpo-42161: Add _PyLong_GetZero() and _PyLong_GetOne() (GH-22993)
Add _PyLong_GetZero() and _PyLong_GetOne() functions and a new
internal pycore_long.h header file.
Python cannot be built without small integer singletons anymore.
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
index 538aa5a..eee369a 100644
--- a/Include/internal/pycore_interp.h
+++ b/Include/internal/pycore_interp.h
@@ -163,6 +163,11 @@ struct _Py_exc_state {
#define _PY_NSMALLPOSINTS 257
#define _PY_NSMALLNEGINTS 5
+// _PyLong_GetZero() and _PyLong_GetOne() must always be available
+#if _PY_NSMALLPOSINTS < 2
+# error "_PY_NSMALLPOSINTS must be greater than 1"
+#endif
+
// The PyInterpreterState typedef is in Include/pystate.h.
struct _is {
@@ -233,14 +238,12 @@ struct _is {
PyObject *audit_hooks;
-#if _PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS > 0
/* Small integers are preallocated in this array so that they
can be shared.
The integers that are preallocated are those in the range
-_PY_NSMALLNEGINTS (inclusive) to _PY_NSMALLPOSINTS (not inclusive).
*/
PyLongObject* small_ints[_PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS];
-#endif
struct _Py_bytes_state bytes;
struct _Py_unicode_state unicode;
struct _Py_float_state float_state;
diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
new file mode 100644
index 0000000..ec95786
--- /dev/null
+++ b/Include/internal/pycore_long.h
@@ -0,0 +1,43 @@
+#ifndef Py_INTERNAL_LONG_H
+#define Py_INTERNAL_LONG_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+# error "this header requires Py_BUILD_CORE define"
+#endif
+
+#include "pycore_interp.h" // PyInterpreterState.small_ints
+#include "pycore_pystate.h" // _PyThreadState_GET()
+
+// Don't call this function but _PyLong_GetZero() and _PyLong_GetOne()
+static inline PyObject* __PyLong_GetSmallInt_internal(int value)
+{
+ PyThreadState *tstate = _PyThreadState_GET();
+#ifdef Py_DEBUG
+ _Py_EnsureTstateNotNULL(tstate);
+#endif
+ assert(-_PY_NSMALLNEGINTS <= value && value < _PY_NSMALLPOSINTS);
+ size_t index = _PY_NSMALLNEGINTS + value;
+ PyObject *obj = (PyObject*)tstate->interp->small_ints[index];
+ // _PyLong_GetZero() and _PyLong_GetOne() must not be called
+ // before _PyLong_Init() nor after _PyLong_Fini()
+ assert(obj != NULL);
+ return obj;
+}
+
+// Return a borrowed reference to the zero singleton.
+// The function cannot return NULL.
+static inline PyObject* _PyLong_GetZero(void)
+{ return __PyLong_GetSmallInt_internal(0); }
+
+// Return a borrowed reference to the one singleton.
+// The function cannot return NULL.
+static inline PyObject* _PyLong_GetOne(void)
+{ return __PyLong_GetSmallInt_internal(1); }
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERNAL_LONG_H */
diff --git a/Makefile.pre.in b/Makefile.pre.in
index fe226ce..31f61f3 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1117,6 +1117,7 @@
$(srcdir)/Include/internal/pycore_initconfig.h \
$(srcdir)/Include/internal/pycore_interp.h \
$(srcdir)/Include/internal/pycore_list.h \
+ $(srcdir)/Include/internal/pycore_long.h \
$(srcdir)/Include/internal/pycore_object.h \
$(srcdir)/Include/internal/pycore_pathconfig.h \
$(srcdir)/Include/internal/pycore_pyerrors.h \
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 92514d4..ae63eba 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -5,6 +5,7 @@
#include "Python.h"
#include "pycore_bitutils.h" // _Py_popcount32()
#include "pycore_interp.h" // _PY_NSMALLPOSINTS
+#include "pycore_long.h" // __PyLong_GetSmallInt_internal()
#include "pycore_object.h" // _PyObject_InitVar()
#include "pycore_pystate.h" // _Py_IsMainInterpreter()
#include "longintrepr.h"
@@ -19,8 +20,8 @@ class int "PyObject *" "&PyLong_Type"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=ec0275e3422a36e3]*/
-#define NSMALLPOSINTS _PY_NSMALLPOSINTS
#define NSMALLNEGINTS _PY_NSMALLNEGINTS
+#define NSMALLPOSINTS _PY_NSMALLPOSINTS
_Py_IDENTIFIER(little);
_Py_IDENTIFIER(big);
@@ -34,7 +35,6 @@ _Py_IDENTIFIER(big);
PyObject *_PyLong_Zero = NULL;
PyObject *_PyLong_One = NULL;
-#if NSMALLNEGINTS + NSMALLPOSINTS > 0
#define IS_SMALL_INT(ival) (-NSMALLNEGINTS <= (ival) && (ival) < NSMALLPOSINTS)
#define IS_SMALL_UINT(ival) ((ival) < NSMALLPOSINTS)
@@ -42,8 +42,7 @@ static PyObject *
get_small_int(sdigit ival)
{
assert(IS_SMALL_INT(ival));
- PyInterpreterState *interp = _PyInterpreterState_GET();
- PyObject *v = (PyObject*)interp->small_ints[ival + NSMALLNEGINTS];
+ PyObject *v = __PyLong_GetSmallInt_internal(ival);
Py_INCREF(v);
return v;
}
@@ -60,12 +59,6 @@ maybe_small_long(PyLongObject *v)
}
return v;
}
-#else
-#define IS_SMALL_INT(ival) 0
-#define IS_SMALL_UINT(ival) 0
-#define get_small_int(ival) (Py_UNREACHABLE(), NULL)
-#define maybe_small_long(val) (val)
-#endif
/* If a freshly-allocated int is already shared, it must
be a small integer, so negating it must go to PyLong_FromLong */
@@ -2559,8 +2552,9 @@ long_divrem(PyLongObject *a, PyLongObject *b,
if (*prem == NULL) {
return -1;
}
- Py_INCREF(_PyLong_Zero);
- *pdiv = (PyLongObject*)_PyLong_Zero;
+ PyObject *zero = _PyLong_GetZero();
+ Py_INCREF(zero);
+ *pdiv = (PyLongObject*)zero;
return 0;
}
if (size_b == 1) {
@@ -3669,7 +3663,7 @@ l_divmod(PyLongObject *v, PyLongObject *w,
Py_DECREF(div);
return -1;
}
- temp = (PyLongObject *) long_sub(div, (PyLongObject *)_PyLong_One);
+ temp = (PyLongObject *) long_sub(div, (PyLongObject *)_PyLong_GetOne());
if (temp == NULL) {
Py_DECREF(mod);
Py_DECREF(div);
@@ -4078,7 +4072,7 @@ long_invmod(PyLongObject *a, PyLongObject *n)
Py_DECREF(c);
Py_DECREF(n);
- if (long_compare(a, (PyLongObject *)_PyLong_One)) {
+ if (long_compare(a, (PyLongObject *)_PyLong_GetOne())) {
/* a != 1; we don't have an inverse. */
Py_DECREF(a);
Py_DECREF(b);
@@ -4313,7 +4307,7 @@ long_invert(PyLongObject *v)
PyLongObject *x;
if (Py_ABS(Py_SIZE(v)) <=1)
return PyLong_FromLong(-(MEDIUM_VALUE(v)+1));
- x = (PyLongObject *) long_add(v, (PyLongObject *)_PyLong_One);
+ x = (PyLongObject *) long_add(v, (PyLongObject *)_PyLong_GetOne());
if (x == NULL)
return NULL;
_PyLong_Negate(&x);
@@ -5105,7 +5099,8 @@ _PyLong_DivmodNear(PyObject *a, PyObject *b)
/* compare twice the remainder with the divisor, to see
if we need to adjust the quotient and remainder */
- twice_rem = long_lshift((PyObject *)rem, _PyLong_One);
+ PyObject *one = _PyLong_GetOne(); // borrowed reference
+ twice_rem = long_lshift((PyObject *)rem, one);
if (twice_rem == NULL)
goto error;
if (quo_is_neg) {
@@ -5122,9 +5117,9 @@ _PyLong_DivmodNear(PyObject *a, PyObject *b)
if ((Py_SIZE(b) < 0 ? cmp < 0 : cmp > 0) || (cmp == 0 && quo_is_odd)) {
/* fix up quotient */
if (quo_is_neg)
- temp = long_sub(quo, (PyLongObject *)_PyLong_One);
+ temp = long_sub(quo, (PyLongObject *)one);
else
- temp = long_add(quo, (PyLongObject *)_PyLong_One);
+ temp = long_add(quo, (PyLongObject *)one);
Py_DECREF(quo);
quo = (PyLongObject *)temp;
if (quo == NULL)
@@ -5406,7 +5401,7 @@ int_as_integer_ratio_impl(PyObject *self)
if (numerator == NULL) {
return NULL;
}
- ratio_tuple = PyTuple_Pack(2, numerator, _PyLong_One);
+ ratio_tuple = PyTuple_Pack(2, numerator, _PyLong_GetOne());
Py_DECREF(numerator);
return ratio_tuple;
}
@@ -5712,7 +5707,6 @@ PyLong_GetInfo(void)
int
_PyLong_Init(PyThreadState *tstate)
{
-#if NSMALLNEGINTS + NSMALLPOSINTS > 0
for (Py_ssize_t i=0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++) {
sdigit ival = (sdigit)i - NSMALLNEGINTS;
int size = (ival < 0) ? -1 : ((ival == 0) ? 0 : 1);
@@ -5727,7 +5721,6 @@ _PyLong_Init(PyThreadState *tstate)
tstate->interp->small_ints[i] = v;
}
-#endif
if (_Py_IsMainInterpreter(tstate)) {
_PyLong_Zero = PyLong_FromLong(0);
@@ -5759,9 +5752,7 @@ _PyLong_Fini(PyThreadState *tstate)
Py_CLEAR(_PyLong_Zero);
}
-#if NSMALLNEGINTS + NSMALLPOSINTS > 0
for (Py_ssize_t i = 0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++) {
Py_CLEAR(tstate->interp->small_ints[i]);
}
-#endif
}
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 600f33b..18edba8 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -185,6 +185,7 @@
<ClInclude Include="..\Include\internal\pycore_initconfig.h" />
<ClInclude Include="..\Include\internal\pycore_interp.h" />
<ClInclude Include="..\Include\internal\pycore_list.h" />
+ <ClInclude Include="..\Include\internal\pycore_long.h" />
<ClInclude Include="..\Include\internal\pycore_object.h" />
<ClInclude Include="..\Include\internal\pycore_pathconfig.h" />
<ClInclude Include="..\Include\internal\pycore_pyerrors.h" />
diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters
index 75b91d8..281bce1 100644
--- a/PCbuild/pythoncore.vcxproj.filters
+++ b/PCbuild/pythoncore.vcxproj.filters
@@ -537,6 +537,9 @@
<ClInclude Include="..\Include\internal\pycore_list.h">
<Filter>Include\internal</Filter>
</ClInclude>
+ <ClInclude Include="..\Include\internal\pycore_long.h">
+ <Filter>Include\internal</Filter>
+ </ClInclude>
<ClInclude Include="..\Include\internal\pycore_object.h">
<Filter>Include\internal</Filter>
</ClInclude>