From cfb70cb2fdb02457c02b7ffb3792da78d2292ba4 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Wed, 4 Dec 2024 21:37:34 +0100
Subject: [PATCH 01/27] Faster check for small ints in long_dealloc

---
 Objects/longobject.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index 4aa35685b509f2..20362fad3bd012 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3611,24 +3611,28 @@ long_richcompare(PyObject *self, PyObject *other, int op)
     Py_RETURN_RICHCOMPARE(result, 0, op);
 }
 
+static inline int
+/// Return 1 if the object is one of the immortal small ints
+_long_is_small_int(PyObject *op)
+{
+    return (((PyObject *)(&_PyLong_SMALL_INTS[0]) <= op)
+             && (op <= (PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS +_PY_NSMALLPOSINTS]));
+}
 static void
 long_dealloc(PyObject *self)
 {
-    /* This should never get called, but we also don't want to SEGV if
-     * we accidentally decref small Ints out of existence. Instead,
-     * since small Ints are immortal, re-set the reference count.
-     */
-    PyLongObject *pylong = (PyLongObject*)self;
-    if (pylong && _PyLong_IsCompact(pylong)) {
-        stwodigits ival = medium_value(pylong);
-        if (IS_SMALL_INT(ival)) {
-            PyLongObject *small_pylong = (PyLongObject *)get_small_int((sdigit)ival);
-            if (pylong == small_pylong) {
-                _Py_SetImmortal(self);
-                return;
-            }
-        }
+    #ifndef Py_GIL_DISABLED
+    if (_long_is_small_int(self)) {
+        /* This should never get called, but we also don't want to SEGV if
+         * we accidentally decref small Ints out of existence. Instead,
+         * since small Ints are immortal, re-set the reference count.
+         *
+         * See PEP 683, section Accidental De-Immortalizing for details
+         */
+        _Py_SetImmortal(self);
+        return;
     }
+    #endif
     Py_TYPE(self)->tp_free(self);
 }
 

From 426dd09ad15cc3d1d72b086d492b8567ea0b4889 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Wed, 4 Dec 2024 22:14:45 +0000
Subject: [PATCH 02/27] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20b?=
 =?UTF-8?q?lurb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../2024-12-04-22-14-40.gh-issue-127119._hpyFE.rst               | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2024-12-04-22-14-40.gh-issue-127119._hpyFE.rst

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-12-04-22-14-40.gh-issue-127119._hpyFE.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-12-04-22-14-40.gh-issue-127119._hpyFE.rst
new file mode 100644
index 00000000000000..f021bd490f488c
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2024-12-04-22-14-40.gh-issue-127119._hpyFE.rst
@@ -0,0 +1 @@
+Slightly optimize the :class:`int` deallocator.

From 46396428b45085d9643b99e33f51d1491163cb3c Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 20:39:07 +0100
Subject: [PATCH 03/27] Use int immortality bit for small int check

---
 Include/internal/pycore_long.h |  7 +++++--
 Modules/_testcapi/immortal.c   | 10 +++++++++-
 Objects/longobject.c           |  6 ++++--
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index 196b4152280a35..8b05d8a6e1be2a 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -157,13 +157,14 @@ PyAPI_FUNC(int) _PyLong_Size_t_Converter(PyObject *, void *);
 
 /* Long value tag bits:
  * 0-1: Sign bits value = (1-sign), ie. negative=2, positive=0, zero=1.
- * 2: Reserved for immortality bit
+ * 2: Reserved for immortality bit. Set to 1 for the small ints
  * 3+ Unsigned digit count
  */
 #define SIGN_MASK 3
 #define SIGN_ZERO 1
 #define SIGN_NEGATIVE 2
 #define NON_SIZE_BITS 3
+#define IMMORTALITY_BIT_MASK (1 << 2)
 
 /* The functions _PyLong_IsCompact and _PyLong_CompactValue are defined
  * in Include/cpython/longobject.h, since they need to be inline.
@@ -262,6 +263,8 @@ _PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
     return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
 }
 
+#define IMMORTAL_BIT(val) ((_PY_NSMALLNEGINTS <= val < _PY_NSMALLPOSINTS) * IMMORTALITY_BIT_MASK)
+
 #define TAG_FROM_SIGN_AND_SIZE(sign, size) \
     ((uintptr_t)(1 - (sign)) | ((uintptr_t)(size) << NON_SIZE_BITS))
 
@@ -296,7 +299,7 @@ _PyLong_FlipSign(PyLongObject *op) {
         .long_value  = { \
             .lv_tag = TAG_FROM_SIGN_AND_SIZE( \
                 (val) == 0 ? 0 : ((val) < 0 ? -1 : 1), \
-                (val) == 0 ? 0 : 1), \
+                (val) == 0 ? 0 : 1) | IMMORTAL_BIT(val), \
             { ((val) >= 0 ? (val) : -(val)) }, \
         } \
     }
diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index 9f81389811c645..2352a43affb638 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -26,7 +26,15 @@ static PyObject *
 test_immortal_small_ints(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     for (int i = -5; i <= 256; i++) {
-        assert(verify_immortality(PyLong_FromLong(i)));
+        PyObject *obj = PyLong_FromLong(i);
+        assert(verify_immortality(obj));
+        int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & (1 << 2);
+        assert(has_int_immortal_bit);
+    }
+    for (int i = 257; i <= 260; i++) {
+        PyObject *obj = PyLong_FromLong(i);
+        int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & (1 << 2);
+        assert(!has_int_immortal_bit);
     }
     Py_RETURN_NONE;
 }
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 20362fad3bd012..56ee9891f65c47 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3615,9 +3615,11 @@ static inline int
 /// Return 1 if the object is one of the immortal small ints
 _long_is_small_int(PyObject *op)
 {
-    return (((PyObject *)(&_PyLong_SMALL_INTS[0]) <= op)
-             && (op <= (PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS +_PY_NSMALLPOSINTS]));
+    PyLongObject *long_object = (PyLongObject *)op;
+
+    return long_object->long_value.lv_tag | IMMORTALITY_BIT_MASK;
 }
+
 static void
 long_dealloc(PyObject *self)
 {

From 3b6e1fe9bf1dd085e4f74f3ed95af6cc54c8fcce Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 20:44:40 +0100
Subject: [PATCH 04/27] fix compiler warnings

---
 Include/internal/pycore_long.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index 8b05d8a6e1be2a..cb88a81abed85c 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -263,7 +263,7 @@ _PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
     return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
 }
 
-#define IMMORTAL_BIT(val) ((_PY_NSMALLNEGINTS <= val < _PY_NSMALLPOSINTS) * IMMORTALITY_BIT_MASK)
+#define IMMORTAL_BIT(val) ((_PY_NSMALLNEGINTS <= val) && (val < _PY_NSMALLPOSINTS)) * IMMORTALITY_BIT_MASK)
 
 #define TAG_FROM_SIGN_AND_SIZE(sign, size) \
     ((uintptr_t)(1 - (sign)) | ((uintptr_t)(size) << NON_SIZE_BITS))

From 5eca8120f4400aba1cb4878c6977d896d1eef6b2 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 20:52:58 +0100
Subject: [PATCH 05/27] compiler warnings

---
 Include/internal/pycore_long.h | 2 +-
 Objects/longobject.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index cb88a81abed85c..b82c2ca53964b4 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -263,7 +263,7 @@ _PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
     return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
 }
 
-#define IMMORTAL_BIT(val) ((_PY_NSMALLNEGINTS <= val) && (val < _PY_NSMALLPOSINTS)) * IMMORTALITY_BIT_MASK)
+#define IMMORTAL_BIT(val) (((_PY_NSMALLNEGINTS <= val) && (val < _PY_NSMALLPOSINTS)) * IMMORTALITY_BIT_MASK)
 
 #define TAG_FROM_SIGN_AND_SIZE(sign, size) \
     ((uintptr_t)(1 - (sign)) | ((uintptr_t)(size) << NON_SIZE_BITS))
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 56ee9891f65c47..eeabe7a04e24ab 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3617,7 +3617,7 @@ _long_is_small_int(PyObject *op)
 {
     PyLongObject *long_object = (PyLongObject *)op;
 
-    return long_object->long_value.lv_tag | IMMORTALITY_BIT_MASK;
+    return (int)(long_object->long_value.lv_tag | IMMORTALITY_BIT_MASK);
 }
 
 static void

From fedc102ec8d9a33b99bfd49b87de57b4d8187c02 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 21:04:22 +0100
Subject: [PATCH 06/27] some documentation updates

---
 Include/cpython/longintrepr.h | 4 ++--
 Tools/gdb/libpython.py        | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/Include/cpython/longintrepr.h b/Include/cpython/longintrepr.h
index c60ccc463653f9..d4d6eadb8841b6 100644
--- a/Include/cpython/longintrepr.h
+++ b/Include/cpython/longintrepr.h
@@ -76,8 +76,8 @@ typedef long stwodigits; /* signed variant of twodigits */
     - 1: Zero
     - 2: Negative
 
-   The third lowest bit of lv_tag is reserved for an immortality flag, but is
-   not currently used.
+   The third lowest bit of lv_tag is reserved for an immortality flag, and is
+   set to 1 for the small ints.
 
    In a normalized number, ob_digit[ndigits-1] (the most significant
    digit) is never zero.  Also, in all cases, for all valid i,
diff --git a/Tools/gdb/libpython.py b/Tools/gdb/libpython.py
index 698ecbd3b549aa..c6dfba9e0ecb19 100755
--- a/Tools/gdb/libpython.py
+++ b/Tools/gdb/libpython.py
@@ -890,7 +890,7 @@ class PyLongObjectPtr(PyObjectPtr):
 
     def proxyval(self, visited):
         '''
-        Python's Include/longinterpr.h has this declaration:
+        Python's Include/cpython/longinterpr.h has this declaration:
 
             typedef struct _PyLongValue {
                 uintptr_t lv_tag; /* Number of digits, sign and flags */
@@ -909,8 +909,8 @@ def proxyval(self, visited):
                 - 0: Positive
                 - 1: Zero
                 - 2: Negative
-            The third lowest bit of lv_tag is reserved for an immortality flag, but is
-            not currently used.
+            The third lowest bit of lv_tag is reserved for an immortality flag,and is
+            set to 1 for the small ints.
 
         where SHIFT can be either:
             #define PyLong_SHIFT        30

From c733d255e9d707de0540fa02a9dd8436824e447c Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 21:04:49 +0100
Subject: [PATCH 07/27] Update Objects/longobject.c
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
---
 Objects/longobject.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index eeabe7a04e24ab..36ff31c6cdcd5d 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3623,7 +3623,7 @@ _long_is_small_int(PyObject *op)
 static void
 long_dealloc(PyObject *self)
 {
-    #ifndef Py_GIL_DISABLED
+#ifndef Py_GIL_DISABLED
     if (_long_is_small_int(self)) {
         /* This should never get called, but we also don't want to SEGV if
          * we accidentally decref small Ints out of existence. Instead,
@@ -3634,7 +3634,7 @@ long_dealloc(PyObject *self)
         _Py_SetImmortal(self);
         return;
     }
-    #endif
+#endif
     Py_TYPE(self)->tp_free(self);
 }
 

From 39da0ea5649b9e09020c0b59fbf72f5f0837ca15 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 21:06:35 +0100
Subject: [PATCH 08/27] Update Tools/gdb/libpython.py

---
 Tools/gdb/libpython.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/gdb/libpython.py b/Tools/gdb/libpython.py
index c6dfba9e0ecb19..5013da2b74c5e0 100755
--- a/Tools/gdb/libpython.py
+++ b/Tools/gdb/libpython.py
@@ -909,7 +909,7 @@ def proxyval(self, visited):
                 - 0: Positive
                 - 1: Zero
                 - 2: Negative
-            The third lowest bit of lv_tag is reserved for an immortality flag,and is
+            The third lowest bit of lv_tag is reserved for an immortality flag, and is
             set to 1 for the small ints.
 
         where SHIFT can be either:

From 5058e53c4e62c8181914f084f7b17ac50cf1a8d7 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 22:10:00 +0100
Subject: [PATCH 09/27] tests!

---
 Include/internal/pycore_long.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index b82c2ca53964b4..f3e7073e0460d2 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -263,7 +263,7 @@ _PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
     return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
 }
 
-#define IMMORTAL_BIT(val) (((_PY_NSMALLNEGINTS <= val) && (val < _PY_NSMALLPOSINTS)) * IMMORTALITY_BIT_MASK)
+#define IMMORTAL_BIT(val) (((-_PY_NSMALLNEGINTS <= val) && (val < _PY_NSMALLPOSINTS)) * IMMORTALITY_BIT_MASK)
 
 #define TAG_FROM_SIGN_AND_SIZE(sign, size) \
     ((uintptr_t)(1 - (sign)) | ((uintptr_t)(size) << NON_SIZE_BITS))

From 8a3d00fe222f2fdc1b5867cb4e88725e884cf281 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 22:34:21 +0100
Subject: [PATCH 10/27] tests!

---
 Objects/longobject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index 36ff31c6cdcd5d..2a78abf8f86918 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3617,7 +3617,7 @@ _long_is_small_int(PyObject *op)
 {
     PyLongObject *long_object = (PyLongObject *)op;
 
-    return (int)(long_object->long_value.lv_tag | IMMORTALITY_BIT_MASK);
+    return (int)(long_object->long_value.lv_tag & IMMORTALITY_BIT_MASK);
 }
 
 static void

From 878207ab70b658dbef1e22286b2ed990a200ed8b Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Thu, 5 Dec 2024 23:41:56 +0100
Subject: [PATCH 11/27] update _PyLong_IsNonNegativeCompact

---
 Include/internal/pycore_long.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index f3e7073e0460d2..1456c204cb8349 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -195,7 +195,7 @@ PyAPI_FUNC(int) _PyLong_Size_t_Converter(PyObject *, void *);
 static inline int
 _PyLong_IsNonNegativeCompact(const PyLongObject* op) {
     assert(PyLong_Check(op));
-    return op->long_value.lv_tag <= (1 << NON_SIZE_BITS);
+    return ((op->long_value.lv_tag & ~IMMORTALITY_BIT_MASK) <= (1 << NON_SIZE_BITS));
 }
 
 

From 068a16acd258a73495a1cef86bc1fa5da92ad62e Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Wed, 11 Dec 2024 20:04:22 +0100
Subject: [PATCH 12/27] Apply suggestions from code review

Co-authored-by: Mark Shannon <mark@hotpy.org>
---
 Include/internal/pycore_long.h | 2 +-
 Objects/longobject.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index 1456c204cb8349..0a52279960d27c 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -157,7 +157,7 @@ PyAPI_FUNC(int) _PyLong_Size_t_Converter(PyObject *, void *);
 
 /* Long value tag bits:
  * 0-1: Sign bits value = (1-sign), ie. negative=2, positive=0, zero=1.
- * 2: Reserved for immortality bit. Set to 1 for the small ints
+ * 2: Set to 1 for the small ints
  * 3+ Unsigned digit count
  */
 #define SIGN_MASK 3
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 2a78abf8f86918..bb98c603c2e881 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3617,7 +3617,7 @@ _long_is_small_int(PyObject *op)
 {
     PyLongObject *long_object = (PyLongObject *)op;
 
-    return (int)(long_object->long_value.lv_tag & IMMORTALITY_BIT_MASK);
+    return (long_object->long_value.lv_tag & IMMORTALITY_BIT_MASK) != 0;
 }
 
 static void

From a65ec5a6d3f122c1af473a3e4817c340587fb73d Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Wed, 11 Dec 2024 20:04:39 +0100
Subject: [PATCH 13/27] review comments

---
 Include/internal/pycore_long.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/Include/internal/pycore_long.h b/Include/internal/pycore_long.h
index 1456c204cb8349..9cde805e68e893 100644
--- a/Include/internal/pycore_long.h
+++ b/Include/internal/pycore_long.h
@@ -263,8 +263,6 @@ _PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
     return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
 }
 
-#define IMMORTAL_BIT(val) (((-_PY_NSMALLNEGINTS <= val) && (val < _PY_NSMALLPOSINTS)) * IMMORTALITY_BIT_MASK)
-
 #define TAG_FROM_SIGN_AND_SIZE(sign, size) \
     ((uintptr_t)(1 - (sign)) | ((uintptr_t)(size) << NON_SIZE_BITS))
 
@@ -299,7 +297,7 @@ _PyLong_FlipSign(PyLongObject *op) {
         .long_value  = { \
             .lv_tag = TAG_FROM_SIGN_AND_SIZE( \
                 (val) == 0 ? 0 : ((val) < 0 ? -1 : 1), \
-                (val) == 0 ? 0 : 1) | IMMORTAL_BIT(val), \
+                (val) == 0 ? 0 : 1) | IMMORTALITY_BIT_MASK, \
             { ((val) >= 0 ? (val) : -(val)) }, \
         } \
     }

From 32b6e44268cc66d104d94f27dde799e257f3ccb9 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Wed, 11 Dec 2024 20:05:56 +0100
Subject: [PATCH 14/27] spacing

---
 Objects/longobject.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index bb98c603c2e881..f3e4aeb7141651 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3616,7 +3616,6 @@ static inline int
 _long_is_small_int(PyObject *op)
 {
     PyLongObject *long_object = (PyLongObject *)op;
-
     return (long_object->long_value.lv_tag & IMMORTALITY_BIT_MASK) != 0;
 }
 

From e232ca4b4ceb106ea6146b677c88f7b476e56ea5 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Wed, 11 Dec 2024 21:21:01 +0100
Subject: [PATCH 15/27] Update Tools/gdb/libpython.py

---
 Tools/gdb/libpython.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Tools/gdb/libpython.py b/Tools/gdb/libpython.py
index 5013da2b74c5e0..97d7517208d2a7 100755
--- a/Tools/gdb/libpython.py
+++ b/Tools/gdb/libpython.py
@@ -909,8 +909,7 @@ def proxyval(self, visited):
                 - 0: Positive
                 - 1: Zero
                 - 2: Negative
-            The third lowest bit of lv_tag is reserved for an immortality flag, and is
-            set to 1 for the small ints.
+            The third lowest bit of lv_tag is set to 1 for the small ints and 0 otherwise.
 
         where SHIFT can be either:
             #define PyLong_SHIFT        30

From 99a2fc755fb25463c7b587bdecf7fb938de65a57 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Fri, 13 Dec 2024 11:52:58 +0100
Subject: [PATCH 16/27] whitespace

---
 Objects/longobject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index a59f3f80ff8b3a..5ec88089f64853 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3655,7 +3655,7 @@ long_dealloc(PyObject *self)
         _Py_SetImmortal(self);
         return;
     }
-#endif    
+#endif
     if (PyLong_CheckExact(self) && _PyLong_IsCompact((PyLongObject *)self)) {
         _Py_FREELIST_FREE(ints, self, PyObject_Free);
         return;

From 989486604d7a6bab50878136ea97f198f824d938 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Tue, 17 Dec 2024 23:33:17 +0100
Subject: [PATCH 17/27] Apply suggestions from code review

---
 Modules/_testcapi/immortal.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index 2352a43affb638..8571530404ea98 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -33,8 +33,10 @@ test_immortal_small_ints(PyObject *self, PyObject *Py_UNUSED(ignored))
     }
     for (int i = 257; i <= 260; i++) {
         PyObject *obj = PyLong_FromLong(i);
+        assert(obj);
         int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & (1 << 2);
         assert(!has_int_immortal_bit);
+        Py_DECREF(obj);
     }
     Py_RETURN_NONE;
 }

From ebc7e17afc983aa85b041a0fa12feda1fd183411 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 16:40:14 +0100
Subject: [PATCH 18/27] Update Modules/_testcapi/immortal.c

Co-authored-by: Mark Shannon <mark@hotpy.org>
---
 Modules/_testcapi/immortal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index 8571530404ea98..29315514214a59 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -28,7 +28,7 @@ test_immortal_small_ints(PyObject *self, PyObject *Py_UNUSED(ignored))
     for (int i = -5; i <= 256; i++) {
         PyObject *obj = PyLong_FromLong(i);
         assert(verify_immortality(obj));
-        int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & (1 << 2);
+        int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & IMMORTALITY_BIT_MASK;
         assert(has_int_immortal_bit);
     }
     for (int i = 257; i <= 260; i++) {

From aaf110b70d9916a582d3a220f16e697da5176aa6 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 16:40:22 +0100
Subject: [PATCH 19/27] Update Modules/_testcapi/immortal.c

Co-authored-by: Mark Shannon <mark@hotpy.org>
---
 Modules/_testcapi/immortal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index 29315514214a59..5599b38ca395eb 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -34,7 +34,7 @@ test_immortal_small_ints(PyObject *self, PyObject *Py_UNUSED(ignored))
     for (int i = 257; i <= 260; i++) {
         PyObject *obj = PyLong_FromLong(i);
         assert(obj);
-        int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & (1 << 2);
+        int has_int_immortal_bit = ((PyLongObject *)obj)->long_value.lv_tag & IMMORTALITY_BIT_MASK;
         assert(!has_int_immortal_bit);
         Py_DECREF(obj);
     }

From 8fcc1d01f609d3fed549813622e9eed0129d6e67 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 16:40:32 +0100
Subject: [PATCH 20/27] Update Include/cpython/longintrepr.h

Co-authored-by: Mark Shannon <mark@hotpy.org>
---
 Include/cpython/longintrepr.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Include/cpython/longintrepr.h b/Include/cpython/longintrepr.h
index 5e65fec63759df..1b1a1bf6b7cf75 100644
--- a/Include/cpython/longintrepr.h
+++ b/Include/cpython/longintrepr.h
@@ -76,7 +76,7 @@ typedef long stwodigits; /* signed variant of twodigits */
     - 1: Zero
     - 2: Negative
 
-   The third lowest bit of lv_tag is reserved for an immortality flag, and is
+   The third lowest bit of lv_tag is
    set to 1 for the small ints.
 
    In a normalized number, ob_digit[ndigits-1] (the most significant

From ebb0bca50a2960ff86b2e868f35fdb51ac4b58d0 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 16:45:45 +0100
Subject: [PATCH 21/27] review comments

---
 Objects/longobject.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index 11a77f826493c0..78e42617c69c5a 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3627,13 +3627,11 @@ void
 _PyLong_ExactDealloc(PyObject *self)
 {
     assert(PyLong_CheckExact(self));
-#ifndef Py_GIL_DISABLED
     if (_long_is_small_int(self)) {
         // See PEP 683, section Accidental De-Immortalizing for details
         _Py_SetImmortal(self);
         return;
     }
-#endif
     if (_PyLong_IsCompact((PyLongObject *)self)) {
         _Py_FREELIST_FREE(ints, self, PyObject_Free);
         return;
@@ -3644,7 +3642,6 @@ _PyLong_ExactDealloc(PyObject *self)
 static void
 long_dealloc(PyObject *self)
 {
-#ifndef Py_GIL_DISABLED
     if (_long_is_small_int(self)) {
         /* This should never get called, but we also don't want to SEGV if
          * we accidentally decref small Ints out of existence. Instead,
@@ -3655,7 +3652,6 @@ long_dealloc(PyObject *self)
         _Py_SetImmortal(self);
         return;
     }
-#endif
     if (PyLong_CheckExact(self) && _PyLong_IsCompact((PyLongObject *)self)) {
         _Py_FREELIST_FREE(ints, self, PyObject_Free);
         return;

From 8d8e7942f0524349a0a99361a1065c4d369d8dd6 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 20:20:37 +0100
Subject: [PATCH 22/27] include pycore_long.h

---
 Modules/_testcapi/immortal.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index 5599b38ca395eb..4c4621d8935d04 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -1,4 +1,5 @@
 #include "parts.h"
+#include "internal/pycore_long.h"   // IMMORTALITY_BIT_MASK
 
 int verify_immortality(PyObject *object)
 {

From 4a07ba1d0b0ff1f6eaae9d27572b970de5d54761 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 20:23:50 +0100
Subject: [PATCH 23/27] header

---
 Modules/_testcapi/immortal.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index 4c4621d8935d04..cec2253647b55b 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -1,3 +1,7 @@
+#ifndef Py_BUILD_CORE_BUILTIN
+#  define Py_BUILD_CORE_MODULE 1
+#endif
+
 #include "parts.h"
 #include "internal/pycore_long.h"   // IMMORTALITY_BIT_MASK
 

From 1d5b2e08845397d05bd0d393af22906d415e96fc Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 20:26:42 +0100
Subject: [PATCH 24/27] include pycore_long.h

---
 Modules/_testcapi/immortal.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/Modules/_testcapi/immortal.c b/Modules/_testcapi/immortal.c
index cec2253647b55b..2d366762717ff4 100644
--- a/Modules/_testcapi/immortal.c
+++ b/Modules/_testcapi/immortal.c
@@ -1,8 +1,6 @@
-#ifndef Py_BUILD_CORE_BUILTIN
-#  define Py_BUILD_CORE_MODULE 1
-#endif
-
 #include "parts.h"
+
+#define Py_BUILD_CORE
 #include "internal/pycore_long.h"   // IMMORTALITY_BIT_MASK
 
 int verify_immortality(PyObject *object)

From cfb91201527e6c344d0f558e586a35e35239fd00 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Sun, 22 Dec 2024 22:20:37 +0100
Subject: [PATCH 25/27] debug build failure

---
 Objects/longobject.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index 78e42617c69c5a..c9b6d3c2cfce0c 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3649,7 +3649,9 @@ long_dealloc(PyObject *self)
          *
          * See PEP 683, section Accidental De-Immortalizing for details
          */
+#ifndef Py_GIL_DISABLED
         _Py_SetImmortal(self);
+#endif
         return;
     }
     if (PyLong_CheckExact(self) && _PyLong_IsCompact((PyLongObject *)self)) {

From b4c8444746e097a22a2b34e1a6c5bd0d20b7b1d1 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Mon, 23 Dec 2024 21:46:54 +0100
Subject: [PATCH 26/27] fix bug when copying the immortal bit

---
 Objects/longobject.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index c9b6d3c2cfce0c..f611e1c453ca10 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3649,9 +3649,8 @@ long_dealloc(PyObject *self)
          *
          * See PEP 683, section Accidental De-Immortalizing for details
          */
-#ifndef Py_GIL_DISABLED
+        assert(0);
         _Py_SetImmortal(self);
-#endif
         return;
     }
     if (PyLong_CheckExact(self) && _PyLong_IsCompact((PyLongObject *)self)) {
@@ -6019,7 +6018,7 @@ long_subtype_new(PyTypeObject *type, PyObject *x, PyObject *obase)
         return NULL;
     }
     assert(PyLong_Check(newobj));
-    newobj->long_value.lv_tag = tmp->long_value.lv_tag;
+    newobj->long_value.lv_tag = tmp->long_value.lv_tag & ~IMMORTALITY_BIT_MASK;
     for (i = 0; i < n; i++) {
         newobj->long_value.ob_digit[i] = tmp->long_value.ob_digit[i];
     }

From f76c0e2a58ad5cb8c9b6ce476f8d4cbcd16868f1 Mon Sep 17 00:00:00 2001
From: Pieter Eendebak <pieter.eendebak@gmail.com>
Date: Mon, 23 Dec 2024 22:37:33 +0100
Subject: [PATCH 27/27] add assert to make sure the immortal bit is not set on
 subclasses

---
 Objects/longobject.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Objects/longobject.c b/Objects/longobject.c
index f611e1c453ca10..13cdf64c2a2f06 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3620,7 +3620,9 @@ static inline int
 _long_is_small_int(PyObject *op)
 {
     PyLongObject *long_object = (PyLongObject *)op;
-    return (long_object->long_value.lv_tag & IMMORTALITY_BIT_MASK) != 0;
+    int is_small_int = (long_object->long_value.lv_tag & IMMORTALITY_BIT_MASK) != 0;
+    assert((!is_small_int) || PyLong_CheckExact(op));
+    return is_small_int;
 }
 
 void
@@ -3649,7 +3651,6 @@ long_dealloc(PyObject *self)
          *
          * See PEP 683, section Accidental De-Immortalizing for details
          */
-        assert(0);
         _Py_SetImmortal(self);
         return;
     }