GH-101291: Rearrange the size bits in PyLongObject (GH-102464)

* Eliminate all remaining uses of Py_SIZE and Py_SET_SIZE on PyLongObject, adding asserts.

* Change layout of size/sign bits in longobject to support future addition of immortal ints and tagged medium ints.

* Add functions to hide some internals of long object, and for setting sign and digit count.

* Replace uses of IS_MEDIUM_VALUE macro with _PyLong_IsCompact().

1 files changed, 9 insertions, 10 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index ce2a58b..f1fec0b 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -345,8 +345,7 @@ dummy_func(
             DEOPT_IF(!PyList_CheckExact(list), BINARY_SUBSCR);
 
             // Deopt unless 0 <= sub < PyList_Size(list)
-            DEOPT_IF(!_PyLong_IsPositiveSingleDigit(sub), BINARY_SUBSCR);
-            assert(((PyLongObject *)_PyLong_GetZero())->long_value.ob_digit[0] == 0);
+            DEOPT_IF(!_PyLong_IsNonNegativeCompact((PyLongObject *)sub), BINARY_SUBSCR);
             Py_ssize_t index = ((PyLongObject*)sub)->long_value.ob_digit[0];
             DEOPT_IF(index >= PyList_GET_SIZE(list), BINARY_SUBSCR);
             STAT_INC(BINARY_SUBSCR, hit);
@@ -363,8 +362,7 @@ dummy_func(
             DEOPT_IF(!PyTuple_CheckExact(tuple), BINARY_SUBSCR);
 
             // Deopt unless 0 <= sub < PyTuple_Size(list)
-            DEOPT_IF(!_PyLong_IsPositiveSingleDigit(sub), BINARY_SUBSCR);
-            assert(((PyLongObject *)_PyLong_GetZero())->long_value.ob_digit[0] == 0);
+            DEOPT_IF(!_PyLong_IsNonNegativeCompact((PyLongObject *)sub), BINARY_SUBSCR);
             Py_ssize_t index = ((PyLongObject*)sub)->long_value.ob_digit[0];
             DEOPT_IF(index >= PyTuple_GET_SIZE(tuple), BINARY_SUBSCR);
             STAT_INC(BINARY_SUBSCR, hit);
@@ -456,7 +454,7 @@ dummy_func(
             DEOPT_IF(!PyList_CheckExact(list), STORE_SUBSCR);
 
             // Ensure nonnegative, zero-or-one-digit ints.
-            DEOPT_IF(!_PyLong_IsPositiveSingleDigit(sub), STORE_SUBSCR);
+            DEOPT_IF(!_PyLong_IsNonNegativeCompact((PyLongObject *)sub), STORE_SUBSCR);
             Py_ssize_t index = ((PyLongObject*)sub)->long_value.ob_digit[0];
             // Ensure index < len(list)
             DEOPT_IF(index >= PyList_GET_SIZE(list), STORE_SUBSCR);
@@ -1755,12 +1753,13 @@ dummy_func(
             assert(cframe.use_tracing == 0);
             DEOPT_IF(!PyLong_CheckExact(left), COMPARE_AND_BRANCH);
             DEOPT_IF(!PyLong_CheckExact(right), COMPARE_AND_BRANCH);
-            DEOPT_IF((size_t)(Py_SIZE(left) + 1) > 2, COMPARE_AND_BRANCH);
-            DEOPT_IF((size_t)(Py_SIZE(right) + 1) > 2, COMPARE_AND_BRANCH);
+            DEOPT_IF(!_PyLong_IsCompact((PyLongObject *)left), COMPARE_AND_BRANCH);
+            DEOPT_IF(!_PyLong_IsCompact((PyLongObject *)right), COMPARE_AND_BRANCH);
             STAT_INC(COMPARE_AND_BRANCH, hit);
-            assert(Py_ABS(Py_SIZE(left)) <= 1 && Py_ABS(Py_SIZE(right)) <= 1);
-            Py_ssize_t ileft = Py_SIZE(left) * ((PyLongObject *)left)->long_value.ob_digit[0];
-            Py_ssize_t iright = Py_SIZE(right) * ((PyLongObject *)right)->long_value.ob_digit[0];
+            assert(_PyLong_DigitCount((PyLongObject *)left) <= 1 &&
+                   _PyLong_DigitCount((PyLongObject *)right) <= 1);
+            Py_ssize_t ileft = _PyLong_CompactValue((PyLongObject *)left);
+            Py_ssize_t iright = _PyLong_CompactValue((PyLongObject *)right);
             // 2 if <, 4 if >, 8 if ==; this matches the low 4 bits of the oparg
             int sign_ish = COMPARISON_BIT(ileft, iright);
             _Py_DECREF_SPECIALIZED(left, (destructor)PyObject_Free);