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Implement PEP 412: Key-sharing dictionaries (closes #13903) 

Patch from Mark Shannon.
This commit is contained in:
Benjamin Peterson 2012-04-23 11:24:50 -04:00
parent 80d07f8251
commit 7d95e40721
12 changed files with 1353 additions and 904 deletions
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84
Include/dictobject.h
View File

@ -13,78 +13,20 @@ extern "C" {
tuning dictionaries, and several ideas for possible optimizations.
*/
/*
There are three kinds of slots in the table:
1. Unused. me_key == me_value == NULL
Does not hold an active (key, value) pair now and never did. Unused can
transition to Active upon key insertion. This is the only case in which
me_key is NULL, and is each slot's initial state.
2. Active. me_key != NULL and me_key != dummy and me_value != NULL
Holds an active (key, value) pair. Active can transition to Dummy upon
key deletion. This is the only case in which me_value != NULL.
3. Dummy. me_key == dummy and me_value == NULL
Previously held an active (key, value) pair, but that was deleted and an
active pair has not yet overwritten the slot. Dummy can transition to
Active upon key insertion. Dummy slots cannot be made Unused again
(cannot have me_key set to NULL), else the probe sequence in case of
collision would have no way to know they were once active.
Note: .popitem() abuses the me_hash field of an Unused or Dummy slot to
hold a search finger. The me_hash field of Unused or Dummy slots has no
meaning otherwise.
*/
/* PyDict_MINSIZE is the minimum size of a dictionary. This many slots are
* allocated directly in the dict object (in the ma_smalltable member).
* It must be a power of 2, and at least 4. 8 allows dicts with no more
* than 5 active entries to live in ma_smalltable (and so avoid an
* additional malloc); instrumentation suggested this suffices for the
* majority of dicts (consisting mostly of usually-small instance dicts and
* usually-small dicts created to pass keyword arguments).
*/
#ifndef Py_LIMITED_API
#define PyDict_MINSIZE 8
typedef struct _dictkeysobject PyDictKeysObject;
/* The ma_values pointer is NULL for a combined table
* or points to an array of PyObject* for a split table
*/
typedef struct {
/* Cached hash code of me_key. */
Py_hash_t me_hash;
PyObject *me_key;
PyObject *me_value;
} PyDictEntry;
/*
To ensure the lookup algorithm terminates, there must be at least one Unused
slot (NULL key) in the table.
The value ma_fill is the number of non-NULL keys (sum of Active and Dummy);
ma_used is the number of non-NULL, non-dummy keys (== the number of non-NULL
values == the number of Active items).
To avoid slowing down lookups on a near-full table, we resize the table when
it's two-thirds full.
*/
typedef struct _dictobject PyDictObject;
struct _dictobject {
PyObject_HEAD
Py_ssize_t ma_fill; /* # Active + # Dummy */
Py_ssize_t ma_used; /* # Active */
Py_ssize_t ma_used;
PyDictKeysObject *ma_keys;
PyObject **ma_values;
} PyDictObject;
/* The table contains ma_mask + 1 slots, and that's a power of 2.
* We store the mask instead of the size because the mask is more
* frequently needed.
*/
Py_ssize_t ma_mask;
/* ma_table points to ma_smalltable for small tables, else to
* additional malloc'ed memory. ma_table is never NULL! This rule
* saves repeated runtime null-tests in the workhorse getitem and
* setitem calls.
*/
PyDictEntry *ma_table;
PyDictEntry *(*ma_lookup)(PyDictObject *mp, PyObject *key, Py_hash_t hash);
PyDictEntry ma_smalltable[PyDict_MINSIZE];
};
#endif /* Py_LIMITED_API */
PyAPI_DATA(PyTypeObject) PyDict_Type;
@ -117,6 +59,8 @@ PyAPI_FUNC(void) PyDict_Clear(PyObject *mp);
PyAPI_FUNC(int) PyDict_Next(
PyObject *mp, Py_ssize_t *pos, PyObject **key, PyObject **value);
#ifndef Py_LIMITED_API
PyDictKeysObject *_PyDict_NewKeysForClass(void);
PyAPI_FUNC(PyObject *) PyObject_GenericGetDict(PyObject *, void *);
PyAPI_FUNC(int) _PyDict_Next(
PyObject *mp, Py_ssize_t *pos, PyObject **key, PyObject **value, Py_hash_t *hash);
#endif
@ -131,6 +75,7 @@ PyAPI_FUNC(int) _PyDict_Contains(PyObject *mp, PyObject *key, Py_hash_t hash);
PyAPI_FUNC(PyObject *) _PyDict_NewPresized(Py_ssize_t minused);
PyAPI_FUNC(void) _PyDict_MaybeUntrack(PyObject *mp);
PyAPI_FUNC(int) _PyDict_HasOnlyStringKeys(PyObject *mp);
#define _PyDict_HasSplitTable(d) ((d)->ma_values != NULL)
PyAPI_FUNC(int) PyDict_ClearFreeList(void);
#endif
@ -162,6 +107,11 @@ PyAPI_FUNC(int) PyDict_SetItemString(PyObject *dp, const char *key, PyObject *it
PyAPI_FUNC(int) _PyDict_SetItemId(PyObject *dp, struct _Py_Identifier *key, PyObject *item);
PyAPI_FUNC(int) PyDict_DelItemString(PyObject *dp, const char *key);
#ifndef Py_LIMITED_API
int _PyObjectDict_SetItem(PyTypeObject *tp, PyObject **dictptr, PyObject *name, PyObject *value);
PyObject *_PyDict_LoadGlobal(PyDictObject *, PyDictObject *, PyObject *);
#endif
#ifdef __cplusplus
}
#endif

2
Include/object.h
View File

@ -449,6 +449,7 @@ typedef struct _heaptypeobject {
see add_operators() in typeobject.c . */
PyBufferProcs as_buffer;
PyObject *ht_name, *ht_slots, *ht_qualname;
struct _dictkeysobject *ht_cached_keys;
/* here are optional user slots, followed by the members. */
} PyHeapTypeObject;
@ -517,7 +518,6 @@ PyAPI_FUNC(PyObject *) _PyObject_NextNotImplemented(PyObject *);
PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *);
PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *,
PyObject *, PyObject *);
PyAPI_FUNC(PyObject *) PyObject_GenericGetDict(PyObject *, void *);
PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *);
PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *);
PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *);

21
Lib/test/test_dict.py
View File

@ -321,6 +321,27 @@ class DictTest(unittest.TestCase):
self.assertEqual(hashed2.hash_count, 1)
self.assertEqual(hashed1.eq_count + hashed2.eq_count, 1)
def test_setitem_atomic_at_resize(self):
class Hashed(object):
def __init__(self):
self.hash_count = 0
self.eq_count = 0
def __hash__(self):
self.hash_count += 1
return 42
def __eq__(self, other):
self.eq_count += 1
return id(self) == id(other)
hashed1 = Hashed()
# 5 items
y = {hashed1: 5, 0: 0, 1: 1, 2: 2, 3: 3}
hashed2 = Hashed()
# 6th item forces a resize
y[hashed2] = []
self.assertEqual(hashed1.hash_count, 1)
self.assertEqual(hashed2.hash_count, 1)
self.assertEqual(hashed1.eq_count + hashed2.eq_count, 1)
def test_popitem(self):
# dict.popitem()
for copymode in -1, +1:

4
Lib/test/test_pprint.py
View File

@ -219,6 +219,8 @@ class QueryTestCase(unittest.TestCase):
others.should.not.be: like.this}"""
self.assertEqual(DottedPrettyPrinter().pformat(o), exp)
@unittest.expectedFailure
#See http://bugs.python.org/issue13907
@test.support.cpython_only
def test_set_reprs(self):
# This test creates a complex arrangement of frozensets and
@ -241,10 +243,12 @@ class QueryTestCase(unittest.TestCase):
# Consequently, this test is fragile and
# implementation-dependent. Small changes to Python's sort
# algorithm cause the test to fail when it should pass.
# XXX Or changes to the dictionary implmentation...
self.assertEqual(pprint.pformat(set()), 'set()')
self.assertEqual(pprint.pformat(set(range(3))), '{0, 1, 2}')
self.assertEqual(pprint.pformat(frozenset()), 'frozenset()')
self.assertEqual(pprint.pformat(frozenset(range(3))), 'frozenset({0, 1, 2})')
cube_repr_tgt = """\
{frozenset(): frozenset({frozenset({2}), frozenset({0}), frozenset({1})}),

6
Lib/test/test_sys.py
View File

@ -687,9 +687,9 @@ class SizeofTest(unittest.TestCase):
# method-wrapper (descriptor object)
check({}.__iter__, size(h + '2P'))
# dict
check({}, size(h + '3P2P' + 8*'P2P'))
check({}, size(h + '3P' + '4P' + 8*'P2P'))
longdict = {1:1, 2:2, 3:3, 4:4, 5:5, 6:6, 7:7, 8:8}
check(longdict, size(h + '3P2P' + 8*'P2P') + 16*size('P2P'))
check(longdict, size(h + '3P' + '4P') + 16*size('P2P'))
# dictionary-keyiterator
check({}.keys(), size(h + 'P'))
# dictionary-valueiterator
@ -831,7 +831,7 @@ class SizeofTest(unittest.TestCase):
# type
# (PyTypeObject + PyNumberMethods + PyMappingMethods +
# PySequenceMethods + PyBufferProcs)
s = size(vh + 'P2P15Pl4PP9PP11PI') + size('16Pi17P 3P 10P 2P 3P')
s = size(vh + 'P2P15Pl4PP9PP11PIP') + size('16Pi17P 3P 10P 2P 3P')
check(int, s)
# class
class newstyleclass(object): pass

4
Misc/NEWS
View File

@ -10,6 +10,10 @@ What's New in Python 3.3.0 Alpha 3?
Core and Builtins
-----------------
- Issue #13903: Implement PEP 412. Individual dictionary instances can now share
their keys with other dictionaries. Classes take advantage of this to share
their instance dictionary keys for improved memory and performance.
- Issue #14630: Fix a memory access bug for instances of a subclass of int
with value 0.

227
Objects/dictnotes.txt
View File

@ -1,7 +1,6 @@
NOTES ON OPTIMIZING DICTIONARIES
NOTES ON DICTIONARIES
================================
Principal Use Cases for Dictionaries
------------------------------------
@ -21,7 +20,7 @@ Instance attribute lookup and Global variables
Builtins
Frequent reads. Almost never written.
Size 126 interned strings (as of Py2.3b1).
About 150 interned strings (as of Py3.3).
A few keys are accessed much more frequently than others.
Uniquification
@ -59,44 +58,43 @@ Dynamic Mappings
Characterized by deletions interspersed with adds and replacements.
Performance benefits greatly from the re-use of dummy entries.
Data Layout
-----------
Data Layout (assuming a 32-bit box with 64 bytes per cache line)
----------------------------------------------------------------
Smalldicts (8 entries) are attached to the dictobject structure
and the whole group nearly fills two consecutive cache lines.
Larger dicts use the first half of the dictobject structure (one cache
line) and a separate, continuous block of entries (at 12 bytes each
for a total of 5.333 entries per cache line).
Dictionaries are composed of 3 components:
The dictobject struct itself
A dict-keys object (keys & hashes)
A values array
Tunable Dictionary Parameters
-----------------------------
* PyDict_MINSIZE. Currently set to 8.
Must be a power of two. New dicts have to zero-out every cell.
Each additional 8 consumes 1.5 cache lines. Increasing improves
the sparseness of small dictionaries but costs time to read in
the additional cache lines if they are not already in cache.
That case is common when keyword arguments are passed.
* PyDict_STARTSIZE. Starting size of dict (unless an instance dict).
Currently set to 8. Must be a power of two.
New dicts have to zero-out every cell.
Increasing improves the sparseness of small dictionaries but costs
time to read in the additional cache lines if they are not already
in cache. That case is common when keyword arguments are passed.
Prior to version 3.3, PyDict_MINSIZE was used as the starting size
of a new dict.
* Maximum dictionary load in PyDict_SetItem. Currently set to 2/3.
Increasing this ratio makes dictionaries more dense resulting
in more collisions. Decreasing it improves sparseness at the
expense of spreading entries over more cache lines and at the
* PyDict_MINSIZE. Minimum size of a dict.
Currently set to 4 (to keep instance dicts small).
Must be a power of two. Prior to version 3.3, PyDict_MINSIZE was
set to 8.
* USABLE_FRACTION. Maximum dictionary load in PyDict_SetItem.
Currently set to 2/3. Increasing this ratio makes dictionaries more
dense resulting in more collisions. Decreasing it improves sparseness
at the expense of spreading entries over more cache lines and at the
cost of total memory consumed.
The load test occurs in highly time sensitive code. Efforts
to make the test more complex (for example, varying the load
for different sizes) have degraded performance.
* Growth rate upon hitting maximum load. Currently set to *2.
Raising this to *4 results in half the number of resizes,
less effort to resize, better sparseness for some (but not
all dict sizes), and potentially doubles memory consumption
depending on the size of the dictionary. Setting to *4
eliminates every other resize step.
Raising this to *4 results in half the number of resizes, less
effort to resize, better sparseness for some (but not all dict sizes),
and potentially doubles memory consumption depending on the size of
the dictionary. Setting to *4 eliminates every other resize step.
* Maximum sparseness (minimum dictionary load). What percentage
of entries can be unused before the dictionary shrinks to
@ -126,8 +124,8 @@ __iter__(), iterkeys(), iteritems(), itervalues(), and update().
Also, every dictionary iterates at least twice, once for the memset()
when it is created and once by dealloc().
Dictionary operations involving only a single key can be O(1) unless
resizing is possible. By checking for a resize only when the
Dictionary operations involving only a single key can be O(1) unless
resizing is possible. By checking for a resize only when the
dictionary can grow (and may *require* resizing), other operations
remain O(1), and the odds of resize thrashing or memory fragmentation
are reduced. In particular, an algorithm that empties a dictionary
@ -135,136 +133,51 @@ by repeatedly invoking .pop will see no resizing, which might
not be necessary at all because the dictionary is eventually
discarded entirely.
The key differences between this implementation and earlier versions are:
1. The table can be split into two parts, the keys and the values.
2. There is an additional key-value combination: (key, NULL).
Unlike (<dummy>, NULL) which represents a deleted value, (key, NULL)
represented a yet to be inserted value. This combination can only occur
when the table is split.
3. No small table embedded in the dict,
as this would make sharing of key-tables impossible.
These changes have the following consequences.
1. General dictionaries are slightly larger.
2. All object dictionaries of a single class can share a single key-table,
saving about 60% memory for such cases.
Results of Cache Locality Experiments
-------------------------------------
--------------------------------------
When an entry is retrieved from memory, 4.333 adjacent entries are also
retrieved into a cache line. Since accessing items in cache is *much*
cheaper than a cache miss, an enticing idea is to probe the adjacent
entries as a first step in collision resolution. Unfortunately, the
introduction of any regularity into collision searches results in more
collisions than the current random chaining approach.
Experiments on an earlier design of dictionary, in which all tables were
combined, showed the following:
Exploiting cache locality at the expense of additional collisions fails
to payoff when the entries are already loaded in cache (the expense
is paid with no compensating benefit). This occurs in small dictionaries
where the whole dictionary fits into a pair of cache lines. It also
occurs frequently in large dictionaries which have a common access pattern
where some keys are accessed much more frequently than others. The
more popular entries *and* their collision chains tend to remain in cache.
When an entry is retrieved from memory, several adjacent entries are also
retrieved into a cache line. Since accessing items in cache is *much*
cheaper than a cache miss, an enticing idea is to probe the adjacent
entries as a first step in collision resolution. Unfortunately, the
introduction of any regularity into collision searches results in more
collisions than the current random chaining approach.
To exploit cache locality, change the collision resolution section
in lookdict() and lookdict_string(). Set i^=1 at the top of the
loop and move the i = (i << 2) + i + perturb + 1 to an unrolled
version of the loop.
Exploiting cache locality at the expense of additional collisions fails
to payoff when the entries are already loaded in cache (the expense
is paid with no compensating benefit). This occurs in small dictionaries
where the whole dictionary fits into a pair of cache lines. It also
occurs frequently in large dictionaries which have a common access pattern
where some keys are accessed much more frequently than others. The
more popular entries *and* their collision chains tend to remain in cache.
This optimization strategy can be leveraged in several ways:
To exploit cache locality, change the collision resolution section
in lookdict() and lookdict_string(). Set i^=1 at the top of the
loop and move the i = (i << 2) + i + perturb + 1 to an unrolled
version of the loop.
* If the dictionary is kept sparse (through the tunable parameters),
then the occurrence of additional collisions is lessened.
* If lookdict() and lookdict_string() are specialized for small dicts
and for largedicts, then the versions for large_dicts can be given
an alternate search strategy without increasing collisions in small dicts
which already have the maximum benefit of cache locality.
* If the use case for a dictionary is known to have a random key
access pattern (as opposed to a more common pattern with a Zipf's law
distribution), then there will be more benefit for large dictionaries
because any given key is no more likely than another to already be
in cache.
* In use cases with paired accesses to the same key, the second access
is always in cache and gets no benefit from efforts to further improve
cache locality.
Optimizing the Search of Small Dictionaries
-------------------------------------------
If lookdict() and lookdict_string() are specialized for smaller dictionaries,
then a custom search approach can be implemented that exploits the small
search space and cache locality.
* The simplest example is a linear search of contiguous entries. This is
simple to implement, guaranteed to terminate rapidly, never searches
the same entry twice, and precludes the need to check for dummy entries.
* A more advanced example is a self-organizing search so that the most
frequently accessed entries get probed first. The organization
adapts if the access pattern changes over time. Treaps are ideally
suited for self-organization with the most common entries at the
top of the heap and a rapid binary search pattern. Most probes and
results are all located at the top of the tree allowing them all to
be located in one or two cache lines.
* Also, small dictionaries may be made more dense, perhaps filling all
eight cells to take the maximum advantage of two cache lines.
For split tables, the above will apply to the keys, but the value will
always be in a different cache line from the key.
Strategy Pattern
----------------
Consider allowing the user to set the tunable parameters or to select a
particular search method. Since some dictionary use cases have known
sizes and access patterns, the user may be able to provide useful hints.
1) For example, if membership testing or lookups dominate runtime and memory
is not at a premium, the user may benefit from setting the maximum load
ratio at 5% or 10% instead of the usual 66.7%. This will sharply
curtail the number of collisions but will increase iteration time.
The builtin namespace is a prime example of a dictionary that can
benefit from being highly sparse.
2) Dictionary creation time can be shortened in cases where the ultimate
size of the dictionary is known in advance. The dictionary can be
pre-sized so that no resize operations are required during creation.
Not only does this save resizes, but the key insertion will go
more quickly because the first half of the keys will be inserted into
a more sparse environment than before. The preconditions for this
strategy arise whenever a dictionary is created from a key or item
sequence and the number of *unique* keys is known.
3) If the key space is large and the access pattern is known to be random,
then search strategies exploiting cache locality can be fruitful.
The preconditions for this strategy arise in simulations and
numerical analysis.
4) If the keys are fixed and the access pattern strongly favors some of
the keys, then the entries can be stored contiguously and accessed
with a linear search or treap. This exploits knowledge of the data,
cache locality, and a simplified search routine. It also eliminates
the need to test for dummy entries on each probe. The preconditions
for this strategy arise in symbol tables and in the builtin dictionary.
Readonly Dictionaries
---------------------
Some dictionary use cases pass through a build stage and then move to a
more heavily exercised lookup stage with no further changes to the
dictionary.
An idea that emerged on python-dev is to be able to convert a dictionary
to a read-only state. This can help prevent programming errors and also
provide knowledge that can be exploited for lookup optimization.
The dictionary can be immediately rebuilt (eliminating dummy entries),
resized (to an appropriate level of sparseness), and the keys can be
jostled (to minimize collisions). The lookdict() routine can then
eliminate the test for dummy entries (saving about 1/4 of the time
spent in the collision resolution loop).
An additional possibility is to insert links into the empty spaces
so that dictionary iteration can proceed in len(d) steps instead of
(mp->mask + 1) steps. Alternatively, a separate tuple of keys can be
kept just for iteration.
Caching Lookups
---------------
The idea is to exploit key access patterns by anticipating future lookups
based on previous lookups.
The simplest incarnation is to save the most recently accessed entry.
This gives optimal performance for use cases where every get is followed
by a set or del to the same key.

1773
Objects/dictobject.c
View File

File diff suppressed because it is too large Load Diff

27
Objects/object.c
View File

@ -1188,13 +1188,10 @@ _PyObject_GenericSetAttrWithDict(PyObject *obj, PyObject *name,
if (dict == NULL) {
dictptr = _PyObject_GetDictPtr(obj);
if (dictptr != NULL) {
dict = *dictptr;
if (dict == NULL && value != NULL) {
dict = PyDict_New();
if (dict == NULL)
goto done;
*dictptr = dict;
}
res = _PyObjectDict_SetItem(Py_TYPE(obj), dictptr, name, value);
if (res < 0 && PyErr_ExceptionMatches(PyExc_KeyError))
PyErr_SetObject(PyExc_AttributeError, name);
goto done;
}
}
if (dict != NULL) {
@ -1236,22 +1233,6 @@ PyObject_GenericSetAttr(PyObject *obj, PyObject *name, PyObject *value)
return _PyObject_GenericSetAttrWithDict(obj, name, value, NULL);
}
PyObject *
PyObject_GenericGetDict(PyObject *obj, void *context)
{
PyObject *dict, **dictptr = _PyObject_GetDictPtr(obj);
if (dictptr == NULL) {
PyErr_SetString(PyExc_AttributeError,
"This object has no __dict__");
return NULL;
}
dict = *dictptr;
if (dict == NULL)
*dictptr = dict = PyDict_New();
Py_XINCREF(dict);
return dict;
}
int
PyObject_GenericSetDict(PyObject *obj, PyObject *value, void *context)
{

17
Objects/typeobject.c
View File

@ -14,7 +14,7 @@
MCACHE_MAX_ATTR_SIZE, since it might be a problem if very large
strings are used as attribute names. */
#define MCACHE_MAX_ATTR_SIZE 100
#define MCACHE_SIZE_EXP 10
#define MCACHE_SIZE_EXP 9
#define MCACHE_HASH(version, name_hash) \
(((unsigned int)(version) * (unsigned int)(name_hash)) \
>> (8*sizeof(unsigned int) - MCACHE_SIZE_EXP))
@ -2306,6 +2306,9 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
type->tp_dictoffset = slotoffset;
slotoffset += sizeof(PyObject *);
}
if (type->tp_dictoffset) {
et->ht_cached_keys = _PyDict_NewKeysForClass();
}
if (add_weak) {
assert(!base->tp_itemsize);
type->tp_weaklistoffset = slotoffset;
@ -2411,6 +2414,9 @@ PyType_FromSpec(PyType_Spec *spec)
res->ht_type.tp_doc = tp_doc;
}
}
if (res->ht_type.tp_dictoffset) {
res->ht_cached_keys = _PyDict_NewKeysForClass();
}
if (PyType_Ready(&res->ht_type) < 0)
goto fail;
@ -2767,9 +2773,13 @@ type_traverse(PyTypeObject *type, visitproc visit, void *arg)
return 0;
}
extern void
_PyDictKeys_DecRef(PyDictKeysObject *keys);
static int
type_clear(PyTypeObject *type)
{
PyDictKeysObject *cached_keys;
/* Because of type_is_gc(), the collector only calls this
for heaptypes. */
assert(type->tp_flags & Py_TPFLAGS_HEAPTYPE);
@ -2801,6 +2811,11 @@ type_clear(PyTypeObject *type)
*/
PyType_Modified(type);
cached_keys = ((PyHeapTypeObject *)type)->ht_cached_keys;
if (cached_keys != NULL) {
((PyHeapTypeObject *)type)->ht_cached_keys = NULL;
_PyDictKeys_DecRef(cached_keys);
}
if (type->tp_dict)
PyDict_Clear(type->tp_dict);
Py_CLEAR(type->tp_mro);

81
Python/ceval.c
View File

@ -2123,70 +2123,31 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
w = GETITEM(names, oparg);
if (PyDict_CheckExact(f->f_globals)
&& PyDict_CheckExact(f->f_builtins)) {
if (PyUnicode_CheckExact(w)) {
/* Inline the PyDict_GetItem() calls.
WARNING: this is an extreme speed hack.
Do not try this at home. */
Py_hash_t hash = ((PyASCIIObject *)w)->hash;
if (hash != -1) {
PyDictObject *d;
PyDictEntry *e;
d = (PyDictObject *)(f->f_globals);
e = d->ma_lookup(d, w, hash);
if (e == NULL) {
x = NULL;
break;
}
x = e->me_value;
if (x != NULL) {
Py_INCREF(x);
PUSH(x);
DISPATCH();
}
d = (PyDictObject *)(f->f_builtins);
e = d->ma_lookup(d, w, hash);
if (e == NULL) {
x = NULL;
break;
}
x = e->me_value;
if (x != NULL) {
Py_INCREF(x);
PUSH(x);
DISPATCH();
}
goto load_global_error;
}
}
/* This is the un-inlined version of the code above */
x = PyDict_GetItem(f->f_globals, w);
x = _PyDict_LoadGlobal((PyDictObject *)f->f_globals,
(PyDictObject *)f->f_builtins,
w);
if (x == NULL) {
x = PyDict_GetItem(f->f_builtins, w);
if (x == NULL) {
load_global_error:
format_exc_check_arg(
PyExc_NameError,
GLOBAL_NAME_ERROR_MSG, w);
break;
}
}
Py_INCREF(x);
PUSH(x);
DISPATCH();
}
/* Slow-path if globals or builtins is not a dict */
x = PyObject_GetItem(f->f_globals, w);
if (x == NULL) {
x = PyObject_GetItem(f->f_builtins, w);
if (x == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError))
format_exc_check_arg(
PyExc_NameError,
GLOBAL_NAME_ERROR_MSG, w);
if (!PyErr_Occurred())
format_exc_check_arg(PyExc_NameError,
GLOBAL_NAME_ERROR_MSG, w);
break;
}
}
else {
/* Slow-path if globals or builtins is not a dict */
x = PyObject_GetItem(f->f_globals, w);
if (x == NULL) {
x = PyObject_GetItem(f->f_builtins, w);
if (x == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError))
format_exc_check_arg(
PyExc_NameError,
GLOBAL_NAME_ERROR_MSG, w);
break;
}
}
}
Py_INCREF(x);
PUSH(x);
DISPATCH();

11
Tools/gdb/libpython.py
View File

@ -634,9 +634,14 @@ class PyDictObjectPtr(PyObjectPtr):
Yields a sequence of (PyObjectPtr key, PyObjectPtr value) pairs,
analagous to dict.iteritems()
'''
for i in safe_range(self.field('ma_mask') + 1):
ep = self.field('ma_table') + i
pyop_value = PyObjectPtr.from_pyobject_ptr(ep['me_value'])
keys = self.field('ma_keys')
values = self.field('ma_values')
for i in safe_range(keys['dk_size']):
ep = keys['dk_entries'].address + i
if long(values):
pyop_value = PyObjectPtr.from_pyobject_ptr(values[i])
else:
pyop_value = PyObjectPtr.from_pyobject_ptr(ep['me_value'])
if not pyop_value.is_null():
pyop_key = PyObjectPtr.from_pyobject_ptr(ep['me_key'])
yield (pyop_key, pyop_value)