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| author | Eddie Elizondo <eduardo.elizondorueda@gmail.com> | 2023-04-22 19:39:37 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-04-22 19:39:37 (GMT) |
| commit | ea2c0016502472aa8baa3149050ada776d17a009 (patch) | |
| tree | e9e3935a9b71a1f88ac18c24fe512d199880ff90 /Include/cpython | |
| parent | 916de04fd1838530096336aadb3b94b774ed6c90 (diff) | |
| download | cpython-ea2c0016502472aa8baa3149050ada776d17a009.zip cpython-ea2c0016502472aa8baa3149050ada776d17a009.tar.gz cpython-ea2c0016502472aa8baa3149050ada776d17a009.tar.bz2 | |
gh-84436: Implement Immortal Objects (gh-19474)
This is the implementation of PEP683
Motivation:
The PR introduces the ability to immortalize instances in CPython which bypasses reference counting. Tagging objects as immortal allows up to skip certain operations when we know that the object will be around for the entire execution of the runtime.
Note that this by itself will bring a performance regression to the runtime due to the extra reference count checks. However, this brings the ability of having truly immutable objects that are useful in other contexts such as immutable data sharing between sub-interpreters.
Diffstat (limited to 'Include/cpython')
| -rw-r--r-- | Include/cpython/unicodeobject.h | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/Include/cpython/unicodeobject.h b/Include/cpython/unicodeobject.h index 75a74ff..3394726 100644 --- a/Include/cpython/unicodeobject.h +++ b/Include/cpython/unicodeobject.h @@ -98,9 +98,16 @@ typedef struct { Py_ssize_t length; /* Number of code points in the string */ Py_hash_t hash; /* Hash value; -1 if not set */ struct { - /* If interned is set, the two references from the - dictionary to this object are *not* counted in ob_refcnt. */ - unsigned int interned:1; + /* If interned is non-zero, the two references from the + dictionary to this object are *not* counted in ob_refcnt. + The possible values here are: + 0: Not Interned + 1: Interned + 2: Interned and Immortal + 3: Interned, Immortal, and Static + This categorization allows the runtime to determine the right + cleanup mechanism at runtime shutdown. */ + unsigned int interned:2; /* Character size: - PyUnicode_1BYTE_KIND (1): @@ -135,7 +142,7 @@ typedef struct { unsigned int ascii:1; /* Padding to ensure that PyUnicode_DATA() is always aligned to 4 bytes (see issue #19537 on m68k). */ - unsigned int :26; + unsigned int :25; } state; } PyASCIIObject; @@ -183,6 +190,8 @@ PyAPI_FUNC(int) _PyUnicode_CheckConsistency( /* Interning state. */ #define SSTATE_NOT_INTERNED 0 #define SSTATE_INTERNED_MORTAL 1 +#define SSTATE_INTERNED_IMMORTAL 2 +#define SSTATE_INTERNED_IMMORTAL_STATIC 3 /* Use only if you know it's a string */ static inline unsigned int PyUnicode_CHECK_INTERNED(PyObject *op) { |