gh-112075: Add critical sections for most dict APIs (#114508)

Starts adding thread safety to dict objects.


Use @critical_section for APIs which are exposed via argument clinic and don't directly correlate with a public C API which needs to acquire the lock
Use a _lock_held suffix for keeping changes to complicated functions simple and just wrapping them with a critical section
Acquire and release the lock in an existing function where it won't be overly disruptive to the existing logic

1 files changed, 28 insertions, 2 deletions

diff --git a/Objects/clinic/dictobject.c.h b/Objects/clinic/dictobject.c.h
index 8f532f4..daaef21 100644
--- a/Objects/clinic/dictobject.c.h
+++ b/Objects/clinic/dictobject.c.h
@@ -2,6 +2,7 @@
 preserve
 [clinic start generated code]*/
 
+#include "pycore_critical_section.h"// Py_BEGIN_CRITICAL_SECTION()
 #include "pycore_modsupport.h"    // _PyArg_CheckPositional()
 
 PyDoc_STRVAR(dict_fromkeys__doc__,
@@ -65,6 +66,21 @@ PyDoc_STRVAR(dict___contains____doc__,
 #define DICT___CONTAINS___METHODDEF    \
     {"__contains__", (PyCFunction)dict___contains__, METH_O|METH_COEXIST, dict___contains____doc__},
 
+static PyObject *
+dict___contains___impl(PyDictObject *self, PyObject *key);
+
+static PyObject *
+dict___contains__(PyDictObject *self, PyObject *key)
+{
+    PyObject *return_value = NULL;
+
+    Py_BEGIN_CRITICAL_SECTION(self);
+    return_value = dict___contains___impl(self, key);
+    Py_END_CRITICAL_SECTION();
+
+    return return_value;
+}
+
 PyDoc_STRVAR(dict_get__doc__,
 "get($self, key, default=None, /)\n"
 "--\n"
@@ -93,7 +109,9 @@ dict_get(PyDictObject *self, PyObject *const *args, Py_ssize_t nargs)
     }
     default_value = args[1];
 skip_optional:
+    Py_BEGIN_CRITICAL_SECTION(self);
     return_value = dict_get_impl(self, key, default_value);
+    Py_END_CRITICAL_SECTION();
 
 exit:
     return return_value;
@@ -130,7 +148,9 @@ dict_setdefault(PyDictObject *self, PyObject *const *args, Py_ssize_t nargs)
     }
     default_value = args[1];
 skip_optional:
+    Py_BEGIN_CRITICAL_SECTION(self);
     return_value = dict_setdefault_impl(self, key, default_value);
+    Py_END_CRITICAL_SECTION();
 
 exit:
     return return_value;
@@ -209,7 +229,13 @@ dict_popitem_impl(PyDictObject *self);
 static PyObject *
 dict_popitem(PyDictObject *self, PyObject *Py_UNUSED(ignored))
 {
-    return dict_popitem_impl(self);
+    PyObject *return_value = NULL;
+
+    Py_BEGIN_CRITICAL_SECTION(self);
+    return_value = dict_popitem_impl(self);
+    Py_END_CRITICAL_SECTION();
+
+    return return_value;
 }
 
 PyDoc_STRVAR(dict___sizeof____doc__,
@@ -301,4 +327,4 @@ dict_values(PyDictObject *self, PyObject *Py_UNUSED(ignored))
 {
     return dict_values_impl(self);
 }
-/*[clinic end generated code: output=f3ac47dfbf341b23 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=c8fda06bac5b05f3 input=a9049054013a1b77]*/