gh-111956: Add thread-safe one-time initialization. (gh-111960)

1 files changed, 42 insertions, 47 deletions

diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index ae642e8..c9bf08e 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -518,7 +518,7 @@ class Obj2ModVisitor(PickleVisitor):
         if add_label:
             self.emit("failed:", 1)
             self.emit("Py_XDECREF(tmp);", 1)
-        self.emit("return 1;", 1)
+        self.emit("return -1;", 1)
         self.emit("}", 0)
         self.emit("", 0)
 
@@ -529,7 +529,7 @@ class Obj2ModVisitor(PickleVisitor):
                     "state->%s_type);")
             self.emit(line % (t.name,), 1)
             self.emit("if (isinstance == -1) {", 1)
-            self.emit("return 1;", 2)
+            self.emit("return -1;", 2)
             self.emit("}", 1)
             self.emit("if (isinstance) {", 1)
             self.emit("*out = %s;" % t.name, 2)
@@ -558,7 +558,7 @@ class Obj2ModVisitor(PickleVisitor):
             self.emit("tp = state->%s_type;" % (t.name,), 1)
             self.emit("isinstance = PyObject_IsInstance(obj, tp);", 1)
             self.emit("if (isinstance == -1) {", 1)
-            self.emit("return 1;", 2)
+            self.emit("return -1;", 2)
             self.emit("}", 1)
             self.emit("if (isinstance) {", 1)
             for f in t.fields:
@@ -605,7 +605,7 @@ class Obj2ModVisitor(PickleVisitor):
         self.emit("return 0;", 1)
         self.emit("failed:", 0)
         self.emit("Py_XDECREF(tmp);", 1)
-        self.emit("return 1;", 1)
+        self.emit("return -1;", 1)
         self.emit("}", 0)
         self.emit("", 0)
 
@@ -631,13 +631,13 @@ class Obj2ModVisitor(PickleVisitor):
         ctype = get_c_type(field.type)
         line = "if (PyObject_GetOptionalAttr(obj, state->%s, &tmp) < 0) {"
         self.emit(line % field.name, depth)
-        self.emit("return 1;", depth+1)
+        self.emit("return -1;", depth+1)
         self.emit("}", depth)
         if field.seq:
             self.emit("if (tmp == NULL) {", depth)
             self.emit("tmp = PyList_New(0);", depth+1)
             self.emit("if (tmp == NULL) {", depth+1)
-            self.emit("return 1;", depth+2)
+            self.emit("return -1;", depth+2)
             self.emit("}", depth+1)
             self.emit("}", depth)
             self.emit("{", depth)
@@ -647,7 +647,7 @@ class Obj2ModVisitor(PickleVisitor):
                 message = "required field \\\"%s\\\" missing from %s" % (field.name, name)
                 format = "PyErr_SetString(PyExc_TypeError, \"%s\");"
                 self.emit(format % message, depth+1, reflow=False)
-                self.emit("return 1;", depth+1)
+                self.emit("return -1;", depth+1)
             else:
                 self.emit("if (tmp == NULL || tmp == Py_None) {", depth)
                 self.emit("Py_CLEAR(tmp);", depth+1)
@@ -968,16 +968,16 @@ add_attributes(struct ast_state *state, PyObject *type, const char * const *attr
     int i, result;
     PyObject *s, *l = PyTuple_New(num_fields);
     if (!l)
-        return 0;
+        return -1;
     for (i = 0; i < num_fields; i++) {
         s = PyUnicode_InternFromString(attrs[i]);
         if (!s) {
             Py_DECREF(l);
-            return 0;
+            return -1;
         }
         PyTuple_SET_ITEM(l, i, s);
     }
-    result = PyObject_SetAttr(type, state->_attributes, l) >= 0;
+    result = PyObject_SetAttr(type, state->_attributes, l);
     Py_DECREF(l);
     return result;
 }
@@ -1052,7 +1052,7 @@ static int obj2ast_identifier(struct ast_state *state, PyObject* obj, PyObject**
 {
     if (!PyUnicode_CheckExact(obj) && obj != Py_None) {
         PyErr_SetString(PyExc_TypeError, "AST identifier must be of type str");
-        return 1;
+        return -1;
     }
     return obj2ast_object(state, obj, out, arena);
 }
@@ -1061,7 +1061,7 @@ static int obj2ast_string(struct ast_state *state, PyObject* obj, PyObject** out
 {
     if (!PyUnicode_CheckExact(obj) && !PyBytes_CheckExact(obj)) {
         PyErr_SetString(PyExc_TypeError, "AST string must be of type str");
-        return 1;
+        return -1;
     }
     return obj2ast_object(state, obj, out, arena);
 }
@@ -1071,12 +1071,12 @@ static int obj2ast_int(struct ast_state* Py_UNUSED(state), PyObject* obj, int* o
     int i;
     if (!PyLong_Check(obj)) {
         PyErr_Format(PyExc_ValueError, "invalid integer value: %R", obj);
-        return 1;
+        return -1;
     }
 
     i = PyLong_AsInt(obj);
     if (i == -1 && PyErr_Occurred())
-        return 1;
+        return -1;
     *out = i;
     return 0;
 }
@@ -1102,22 +1102,15 @@ static int add_ast_fields(struct ast_state *state)
             static int
             init_types(struct ast_state *state)
             {
-                // init_types() must not be called after _PyAST_Fini()
-                // has been called
-                assert(state->initialized >= 0);
-
-                if (state->initialized) {
-                    return 1;
-                }
                 if (init_identifiers(state) < 0) {
-                    return 0;
+                    return -1;
                 }
                 state->AST_type = PyType_FromSpec(&AST_type_spec);
                 if (!state->AST_type) {
-                    return 0;
+                    return -1;
                 }
                 if (add_ast_fields(state) < 0) {
-                    return 0;
+                    return -1;
                 }
         '''))
         for dfn in mod.dfns:
@@ -1125,8 +1118,7 @@ static int add_ast_fields(struct ast_state *state)
         self.file.write(textwrap.dedent('''
                 state->recursion_depth = 0;
                 state->recursion_limit = 0;
-                state->initialized = 1;
-                return 1;
+                return 0;
             }
         '''))
 
@@ -1138,12 +1130,12 @@ static int add_ast_fields(struct ast_state *state)
         self.emit('state->%s_type = make_type(state, "%s", state->AST_type, %s, %d,' %
                         (name, name, fields, len(prod.fields)), 1)
         self.emit('%s);' % reflow_c_string(asdl_of(name, prod), 2), 2, reflow=False)
-        self.emit("if (!state->%s_type) return 0;" % name, 1)
+        self.emit("if (!state->%s_type) return -1;" % name, 1)
         if prod.attributes:
-            self.emit("if (!add_attributes(state, state->%s_type, %s_attributes, %d)) return 0;" %
+            self.emit("if (add_attributes(state, state->%s_type, %s_attributes, %d) < 0) return -1;" %
                             (name, name, len(prod.attributes)), 1)
         else:
-            self.emit("if (!add_attributes(state, state->%s_type, NULL, 0)) return 0;" % name, 1)
+            self.emit("if (add_attributes(state, state->%s_type, NULL, 0) < 0) return -1;" % name, 1)
         self.emit_defaults(name, prod.fields, 1)
         self.emit_defaults(name, prod.attributes, 1)
 
@@ -1151,12 +1143,12 @@ static int add_ast_fields(struct ast_state *state)
         self.emit('state->%s_type = make_type(state, "%s", state->AST_type, NULL, 0,' %
                   (name, name), 1)
         self.emit('%s);' % reflow_c_string(asdl_of(name, sum), 2), 2, reflow=False)
-        self.emit("if (!state->%s_type) return 0;" % name, 1)
+        self.emit("if (!state->%s_type) return -1;" % name, 1)
         if sum.attributes:
-            self.emit("if (!add_attributes(state, state->%s_type, %s_attributes, %d)) return 0;" %
+            self.emit("if (add_attributes(state, state->%s_type, %s_attributes, %d) < 0) return -1;" %
                             (name, name, len(sum.attributes)), 1)
         else:
-            self.emit("if (!add_attributes(state, state->%s_type, NULL, 0)) return 0;" % name, 1)
+            self.emit("if (add_attributes(state, state->%s_type, NULL, 0) < 0) return -1;" % name, 1)
         self.emit_defaults(name, sum.attributes, 1)
         simple = is_simple(sum)
         for t in sum.types:
@@ -1170,20 +1162,20 @@ static int add_ast_fields(struct ast_state *state)
         self.emit('state->%s_type = make_type(state, "%s", state->%s_type, %s, %d,' %
                             (cons.name, cons.name, name, fields, len(cons.fields)), 1)
         self.emit('%s);' % reflow_c_string(asdl_of(cons.name, cons), 2), 2, reflow=False)
-        self.emit("if (!state->%s_type) return 0;" % cons.name, 1)
+        self.emit("if (!state->%s_type) return -1;" % cons.name, 1)
         self.emit_defaults(cons.name, cons.fields, 1)
         if simple:
             self.emit("state->%s_singleton = PyType_GenericNew((PyTypeObject *)"
                       "state->%s_type, NULL, NULL);" %
                              (cons.name, cons.name), 1)
-            self.emit("if (!state->%s_singleton) return 0;" % cons.name, 1)
+            self.emit("if (!state->%s_singleton) return -1;" % cons.name, 1)
 
     def emit_defaults(self, name, fields, depth):
         for field in fields:
             if field.opt:
                 self.emit('if (PyObject_SetAttr(state->%s_type, state->%s, Py_None) == -1)' %
                             (name, field.name), depth)
-                self.emit("return 0;", depth+1)
+                self.emit("return -1;", depth+1)
 
 
 class ASTModuleVisitor(PickleVisitor):
@@ -1279,7 +1271,7 @@ class ObjVisitor(PickleVisitor):
         self.emit("if (++state->recursion_depth > state->recursion_limit) {", 1)
         self.emit("PyErr_SetString(PyExc_RecursionError,", 2)
         self.emit('"maximum recursion depth exceeded during ast construction");', 3)
-        self.emit("return 0;", 2)
+        self.emit("return NULL;", 2)
         self.emit("}", 1)
 
     def func_end(self):
@@ -1400,7 +1392,7 @@ PyObject* PyAST_mod2obj(mod_ty t)
     int COMPILER_STACK_FRAME_SCALE = 2;
     PyThreadState *tstate = _PyThreadState_GET();
     if (!tstate) {
-        return 0;
+        return NULL;
     }
     state->recursion_limit = Py_C_RECURSION_LIMIT * COMPILER_STACK_FRAME_SCALE;
     int recursion_depth = Py_C_RECURSION_LIMIT - tstate->c_recursion_remaining;
@@ -1414,7 +1406,7 @@ PyObject* PyAST_mod2obj(mod_ty t)
         PyErr_Format(PyExc_SystemError,
             "AST constructor recursion depth mismatch (before=%d, after=%d)",
             starting_recursion_depth, state->recursion_depth);
-        return 0;
+        return NULL;
     }
     return result;
 }
@@ -1481,7 +1473,8 @@ class ChainOfVisitors:
 
 def generate_ast_state(module_state, f):
     f.write('struct ast_state {\n')
-    f.write('    int initialized;\n')
+    f.write('    _PyOnceFlag once;\n')
+    f.write('    int finalized;\n')
     f.write('    int recursion_depth;\n')
     f.write('    int recursion_limit;\n')
     for s in module_state:
@@ -1501,11 +1494,8 @@ def generate_ast_fini(module_state, f):
     f.write(textwrap.dedent("""
                 Py_CLEAR(_Py_INTERP_CACHED_OBJECT(interp, str_replace_inf));
 
-            #if !defined(NDEBUG)
-                state->initialized = -1;
-            #else
-                state->initialized = 0;
-            #endif
+                state->finalized = 1;
+                state->once = (_PyOnceFlag){0};
             }
 
     """))
@@ -1544,6 +1534,7 @@ def generate_module_def(mod, metadata, f, internal_h):
         #include "pycore_ast.h"
         #include "pycore_ast_state.h"     // struct ast_state
         #include "pycore_ceval.h"         // _Py_EnterRecursiveCall
+        #include "pycore_lock.h"          // _PyOnceFlag
         #include "pycore_interp.h"        // _PyInterpreterState.ast
         #include "pycore_pystate.h"       // _PyInterpreterState_GET()
         #include <stddef.h>
@@ -1556,7 +1547,8 @@ def generate_module_def(mod, metadata, f, internal_h):
         {
             PyInterpreterState *interp = _PyInterpreterState_GET();
             struct ast_state *state = &interp->ast;
-            if (!init_types(state)) {
+            assert(!state->finalized);
+            if (_PyOnceFlag_CallOnce(&state->once, (_Py_once_fn_t *)&init_types, state) < 0) {
                 return NULL;
             }
             return state;
@@ -1570,8 +1562,8 @@ def generate_module_def(mod, metadata, f, internal_h):
     for identifier in state_strings:
         f.write('    if ((state->' + identifier)
         f.write(' = PyUnicode_InternFromString("')
-        f.write(identifier + '")) == NULL) return 0;\n')
-    f.write('    return 1;\n')
+        f.write(identifier + '")) == NULL) return -1;\n')
+    f.write('    return 0;\n')
     f.write('};\n\n')
 
 def write_header(mod, metadata, f):
@@ -1629,6 +1621,9 @@ def write_internal_h_header(mod, f):
     print(textwrap.dedent("""
         #ifndef Py_INTERNAL_AST_STATE_H
         #define Py_INTERNAL_AST_STATE_H
+
+        #include "pycore_lock.h"    // _PyOnceFlag
+
         #ifdef __cplusplus
         extern "C" {
         #endif