bpo-40521: Make bytes singletons per interpreter (GH-21074)
Each interpreter now has its own empty bytes string and single byte
character singletons.
Replace STRINGLIB_EMPTY macro with STRINGLIB_GET_EMPTY() macro.
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
index 697d97a..64e891f 100644
--- a/Include/internal/pycore_interp.h
+++ b/Include/internal/pycore_interp.h
@@ -65,6 +65,11 @@
_Py_error_handler error_handler;
};
+struct _Py_bytes_state {
+ PyBytesObject *characters[256];
+ PyBytesObject *empty_string;
+};
+
struct _Py_unicode_state {
struct _Py_unicode_fs_codec fs_codec;
};
@@ -233,6 +238,7 @@
*/
PyLongObject* small_ints[_PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS];
#endif
+ struct _Py_bytes_state bytes;
struct _Py_unicode_state unicode;
struct _Py_float_state float_state;
/* Using a cache is very effective since typically only a single slice is
diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
index 83ce1d2..9a3063a 100644
--- a/Include/internal/pycore_pylifecycle.h
+++ b/Include/internal/pycore_pylifecycle.h
@@ -63,7 +63,7 @@
extern void _PyTuple_Fini(PyThreadState *tstate);
extern void _PyList_Fini(PyThreadState *tstate);
extern void _PySet_Fini(PyThreadState *tstate);
-extern void _PyBytes_Fini(void);
+extern void _PyBytes_Fini(PyThreadState *tstate);
extern void _PyFloat_Fini(PyThreadState *tstate);
extern void _PySlice_Fini(PyThreadState *tstate);
extern void _PyAsyncGen_Fini(PyThreadState *tstate);
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst b/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst
index 24fd437..95fab36 100644
--- a/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-05-20-01-17-34.bpo-40521.wvAehI.rst
@@ -1,5 +1,9 @@
-The tuple free lists, the empty tuple singleton, the list free list, the empty
-frozenset singleton, the float free list, the slice cache, the dict free lists,
-the frame free list, the asynchronous generator free lists, and the context
-free list are no longer shared by all interpreters: each interpreter now its
-has own free lists and caches.
+Each interpreter now its has own free lists, singletons and caches:
+
+* Free lists: float, tuple, list, dict, frame, context,
+ asynchronous generator.
+* Singletons: empty tuple, empty frozenset, empty bytes string,
+ single byte character.
+* Slice cache.
+
+They are no longer shared by all interpreters.
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index d397214..ce006e1 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -18,9 +18,6 @@
#include "clinic/bytesobject.c.h"
-static PyBytesObject *characters[UCHAR_MAX + 1];
-static PyBytesObject *nullstring;
-
_Py_IDENTIFIER(__bytes__);
/* PyBytesObject_SIZE gives the basic size of a string; any memory allocation
@@ -35,6 +32,15 @@
Py_LOCAL_INLINE(Py_ssize_t) _PyBytesWriter_GetSize(_PyBytesWriter *writer,
char *str);
+
+static struct _Py_bytes_state*
+get_bytes_state(void)
+{
+ PyInterpreterState *interp = _PyInterpreterState_GET();
+ return &interp->bytes;
+}
+
+
/*
For PyBytes_FromString(), the parameter `str' points to a null-terminated
string containing exactly `size' bytes.
@@ -63,9 +69,13 @@
PyBytesObject *op;
assert(size >= 0);
- if (size == 0 && (op = nullstring) != NULL) {
- Py_INCREF(op);
- return (PyObject *)op;
+ if (size == 0) {
+ struct _Py_bytes_state *state = get_bytes_state();
+ op = state->empty_string;
+ if (op != NULL) {
+ Py_INCREF(op);
+ return (PyObject *)op;
+ }
}
if ((size_t)size > (size_t)PY_SSIZE_T_MAX - PyBytesObject_SIZE) {
@@ -88,8 +98,9 @@
op->ob_sval[size] = '\0';
/* empty byte string singleton */
if (size == 0) {
- nullstring = op;
+ struct _Py_bytes_state *state = get_bytes_state();
Py_INCREF(op);
+ state->empty_string = op;
}
return (PyObject *) op;
}
@@ -103,11 +114,13 @@
"Negative size passed to PyBytes_FromStringAndSize");
return NULL;
}
- if (size == 1 && str != NULL &&
- (op = characters[*str & UCHAR_MAX]) != NULL)
- {
- Py_INCREF(op);
- return (PyObject *)op;
+ if (size == 1 && str != NULL) {
+ struct _Py_bytes_state *state = get_bytes_state();
+ op = state->characters[*str & UCHAR_MAX];
+ if (op != NULL) {
+ Py_INCREF(op);
+ return (PyObject *)op;
+ }
}
op = (PyBytesObject *)_PyBytes_FromSize(size, 0);
@@ -119,8 +132,9 @@
memcpy(op->ob_sval, str, size);
/* share short strings */
if (size == 1) {
- characters[*str & UCHAR_MAX] = op;
+ struct _Py_bytes_state *state = get_bytes_state();
Py_INCREF(op);
+ state->characters[*str & UCHAR_MAX] = op;
}
return (PyObject *) op;
}
@@ -138,13 +152,21 @@
"byte string is too long");
return NULL;
}
- if (size == 0 && (op = nullstring) != NULL) {
- Py_INCREF(op);
- return (PyObject *)op;
+
+ struct _Py_bytes_state *state = get_bytes_state();
+ if (size == 0) {
+ op = state->empty_string;
+ if (op != NULL) {
+ Py_INCREF(op);
+ return (PyObject *)op;
+ }
}
- if (size == 1 && (op = characters[*str & UCHAR_MAX]) != NULL) {
- Py_INCREF(op);
- return (PyObject *)op;
+ else if (size == 1) {
+ op = state->characters[*str & UCHAR_MAX];
+ if (op != NULL) {
+ Py_INCREF(op);
+ return (PyObject *)op;
+ }
}
/* Inline PyObject_NewVar */
@@ -157,11 +179,12 @@
memcpy(op->ob_sval, str, size+1);
/* share short strings */
if (size == 0) {
- nullstring = op;
Py_INCREF(op);
- } else if (size == 1) {
- characters[*str & UCHAR_MAX] = op;
+ state->empty_string = op;
+ }
+ else if (size == 1) {
Py_INCREF(op);
+ state->characters[*str & UCHAR_MAX] = op;
}
return (PyObject *) op;
}
@@ -1249,6 +1272,8 @@
/* -------------------------------------------------------------------- */
/* Methods */
+#define STRINGLIB_GET_EMPTY() get_bytes_state()->empty_string
+
#include "stringlib/stringdefs.h"
#include "stringlib/fastsearch.h"
@@ -1261,6 +1286,8 @@
#include "stringlib/transmogrify.h"
+#undef STRINGLIB_GET_EMPTY
+
PyObject *
PyBytes_Repr(PyObject *obj, int smartquotes)
{
@@ -3058,12 +3085,13 @@
}
void
-_PyBytes_Fini(void)
+_PyBytes_Fini(PyThreadState *tstate)
{
- int i;
- for (i = 0; i < UCHAR_MAX + 1; i++)
- Py_CLEAR(characters[i]);
- Py_CLEAR(nullstring);
+ struct _Py_bytes_state* state = &tstate->interp->bytes;
+ for (int i = 0; i < UCHAR_MAX + 1; i++) {
+ Py_CLEAR(state->characters[i]);
+ }
+ Py_CLEAR(state->empty_string);
}
/*********************** Bytes Iterator ****************************/
diff --git a/Objects/stringlib/README.txt b/Objects/stringlib/README.txt
index 8ff6ad8..e1e3292 100644
--- a/Objects/stringlib/README.txt
+++ b/Objects/stringlib/README.txt
@@ -11,10 +11,10 @@
the type used to hold a character (char or Py_UNICODE)
-STRINGLIB_EMPTY
+STRINGLIB_GET_EMPTY()
- a PyObject representing the empty string, only to be used if
- STRINGLIB_MUTABLE is 0
+ returns a PyObject representing the empty string, only to be used if
+ STRINGLIB_MUTABLE is 0. It must not be NULL.
Py_ssize_t STRINGLIB_LEN(PyObject*)
diff --git a/Objects/stringlib/asciilib.h b/Objects/stringlib/asciilib.h
index e69a2c0..8599d38 100644
--- a/Objects/stringlib/asciilib.h
+++ b/Objects/stringlib/asciilib.h
@@ -11,7 +11,7 @@
#define STRINGLIB_CHAR Py_UCS1
#define STRINGLIB_TYPE_NAME "unicode"
#define STRINGLIB_PARSE_CODE "U"
-#define STRINGLIB_EMPTY unicode_empty
+#define STRINGLIB_GET_EMPTY() unicode_empty
#define STRINGLIB_ISSPACE Py_UNICODE_ISSPACE
#define STRINGLIB_ISLINEBREAK BLOOM_LINEBREAK
#define STRINGLIB_ISDECIMAL Py_UNICODE_ISDECIMAL
diff --git a/Objects/stringlib/partition.h b/Objects/stringlib/partition.h
index ed32a6f..3731df5 100644
--- a/Objects/stringlib/partition.h
+++ b/Objects/stringlib/partition.h
@@ -37,10 +37,12 @@
#else
Py_INCREF(str_obj);
PyTuple_SET_ITEM(out, 0, (PyObject*) str_obj);
- Py_INCREF(STRINGLIB_EMPTY);
- PyTuple_SET_ITEM(out, 1, (PyObject*) STRINGLIB_EMPTY);
- Py_INCREF(STRINGLIB_EMPTY);
- PyTuple_SET_ITEM(out, 2, (PyObject*) STRINGLIB_EMPTY);
+ PyObject *empty = (PyObject*)STRINGLIB_GET_EMPTY();
+ assert(empty != NULL);
+ Py_INCREF(empty);
+ PyTuple_SET_ITEM(out, 1, empty);
+ Py_INCREF(empty);
+ PyTuple_SET_ITEM(out, 2, empty);
#endif
return out;
}
@@ -90,10 +92,12 @@
return NULL;
}
#else
- Py_INCREF(STRINGLIB_EMPTY);
- PyTuple_SET_ITEM(out, 0, (PyObject*) STRINGLIB_EMPTY);
- Py_INCREF(STRINGLIB_EMPTY);
- PyTuple_SET_ITEM(out, 1, (PyObject*) STRINGLIB_EMPTY);
+ PyObject *empty = (PyObject*)STRINGLIB_GET_EMPTY();
+ assert(empty != NULL);
+ Py_INCREF(empty);
+ PyTuple_SET_ITEM(out, 0, empty);
+ Py_INCREF(empty);
+ PyTuple_SET_ITEM(out, 1, empty);
Py_INCREF(str_obj);
PyTuple_SET_ITEM(out, 2, (PyObject*) str_obj);
#endif
diff --git a/Objects/stringlib/stringdefs.h b/Objects/stringlib/stringdefs.h
index ce27f3e..c12ecc5 100644
--- a/Objects/stringlib/stringdefs.h
+++ b/Objects/stringlib/stringdefs.h
@@ -1,6 +1,10 @@
#ifndef STRINGLIB_STRINGDEFS_H
#define STRINGLIB_STRINGDEFS_H
+#ifndef STRINGLIB_GET_EMPTY
+# error "STRINGLIB_GET_EMPTY macro must be defined"
+#endif
+
/* this is sort of a hack. there's at least one place (formatting
floats) where some stringlib code takes a different path if it's
compiled as unicode. */
@@ -13,7 +17,6 @@
#define STRINGLIB_CHAR char
#define STRINGLIB_TYPE_NAME "string"
#define STRINGLIB_PARSE_CODE "S"
-#define STRINGLIB_EMPTY nullstring
#define STRINGLIB_ISSPACE Py_ISSPACE
#define STRINGLIB_ISLINEBREAK(x) ((x == '\n') || (x == '\r'))
#define STRINGLIB_ISDECIMAL(x) ((x >= '0') && (x <= '9'))
diff --git a/Objects/stringlib/ucs1lib.h b/Objects/stringlib/ucs1lib.h
index bc4b104..bdf3035 100644
--- a/Objects/stringlib/ucs1lib.h
+++ b/Objects/stringlib/ucs1lib.h
@@ -11,7 +11,7 @@
#define STRINGLIB_CHAR Py_UCS1
#define STRINGLIB_TYPE_NAME "unicode"
#define STRINGLIB_PARSE_CODE "U"
-#define STRINGLIB_EMPTY unicode_empty
+#define STRINGLIB_GET_EMPTY() unicode_empty
#define STRINGLIB_ISSPACE Py_UNICODE_ISSPACE
#define STRINGLIB_ISLINEBREAK BLOOM_LINEBREAK
#define STRINGLIB_ISDECIMAL Py_UNICODE_ISDECIMAL
diff --git a/Objects/stringlib/ucs2lib.h b/Objects/stringlib/ucs2lib.h
index 86a1dff..9d68888 100644
--- a/Objects/stringlib/ucs2lib.h
+++ b/Objects/stringlib/ucs2lib.h
@@ -11,7 +11,7 @@
#define STRINGLIB_CHAR Py_UCS2
#define STRINGLIB_TYPE_NAME "unicode"
#define STRINGLIB_PARSE_CODE "U"
-#define STRINGLIB_EMPTY unicode_empty
+#define STRINGLIB_GET_EMPTY() unicode_empty
#define STRINGLIB_ISSPACE Py_UNICODE_ISSPACE
#define STRINGLIB_ISLINEBREAK BLOOM_LINEBREAK
#define STRINGLIB_ISDECIMAL Py_UNICODE_ISDECIMAL
diff --git a/Objects/stringlib/ucs4lib.h b/Objects/stringlib/ucs4lib.h
index 3c32a93..c7dfa52 100644
--- a/Objects/stringlib/ucs4lib.h
+++ b/Objects/stringlib/ucs4lib.h
@@ -11,7 +11,7 @@
#define STRINGLIB_CHAR Py_UCS4
#define STRINGLIB_TYPE_NAME "unicode"
#define STRINGLIB_PARSE_CODE "U"
-#define STRINGLIB_EMPTY unicode_empty
+#define STRINGLIB_GET_EMPTY() unicode_empty
#define STRINGLIB_ISSPACE Py_UNICODE_ISSPACE
#define STRINGLIB_ISLINEBREAK BLOOM_LINEBREAK
#define STRINGLIB_ISDECIMAL Py_UNICODE_ISDECIMAL
diff --git a/Objects/stringlib/unicodedefs.h b/Objects/stringlib/unicodedefs.h
index 3db5629..e4d4163 100644
--- a/Objects/stringlib/unicodedefs.h
+++ b/Objects/stringlib/unicodedefs.h
@@ -13,7 +13,7 @@
#define STRINGLIB_CHAR Py_UNICODE
#define STRINGLIB_TYPE_NAME "unicode"
#define STRINGLIB_PARSE_CODE "U"
-#define STRINGLIB_EMPTY unicode_empty
+#define STRINGLIB_GET_EMPTY() unicode_empty
#define STRINGLIB_ISSPACE Py_UNICODE_ISSPACE
#define STRINGLIB_ISLINEBREAK BLOOM_LINEBREAK
#define STRINGLIB_ISDECIMAL Py_UNICODE_ISDECIMAL
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index aaea045..4bb32ab 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -1262,9 +1262,7 @@
_PySlice_Fini(tstate);
- if (is_main_interp) {
- _PyBytes_Fini();
- }
+ _PyBytes_Fini(tstate);
_PyUnicode_Fini(tstate);
_PyFloat_Fini(tstate);
_PyLong_Fini(tstate);