gh-87092: Expose assembler to unit tests (#103988)

Include/internal/pycore_compile.h

@@ -103,6 +103,10 @@ PyAPI_FUNC(PyObject*) _PyCompile_OptimizeCfg(
         PyObject *instructions,
         PyObject *consts);
 
+PyAPI_FUNC(PyCodeObject*)
+_PyCompile_Assemble(_PyCompile_CodeUnitMetadata *umd, PyObject *filename,
+                    PyObject *instructions);
+
 #ifdef __cplusplus
 }
 #endif

Include/internal/pycore_global_objects_fini_generated.h

@@ -1029,6 +1029,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(memlimit));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(message));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(metaclass));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(metadata));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(method));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(mod));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(mode));

Include/internal/pycore_global_strings.h

@@ -517,6 +517,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(memlimit)
         STRUCT_FOR_ID(message)
         STRUCT_FOR_ID(metaclass)
+        STRUCT_FOR_ID(metadata)
         STRUCT_FOR_ID(method)
         STRUCT_FOR_ID(mod)
         STRUCT_FOR_ID(mode)

Include/internal/pycore_runtime_init_generated.h

@@ -1023,6 +1023,7 @@ extern "C" {
     INIT_ID(memlimit), \
     INIT_ID(message), \
     INIT_ID(metaclass), \
+    INIT_ID(metadata), \
     INIT_ID(method), \
     INIT_ID(mod), \
     INIT_ID(mode), \

Include/internal/pycore_unicodeobject_generated.h

@@ -1404,6 +1404,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(metaclass);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(metadata);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(method);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);

Lib/test/support/bytecode_helper.py

@@ -3,7 +3,7 @@
 import unittest
 import dis
 import io
-from _testinternalcapi import compiler_codegen, optimize_cfg
+from _testinternalcapi import compiler_codegen, optimize_cfg, assemble_code_object
 
 _UNSPECIFIED = object()
 
@@ -108,6 +108,18 @@ def normalize_insts(self, insts):
             res.append((opcode, arg, *loc))
         return res
 
+    def complete_insts_info(self, insts):
+        # fill in omitted fields in location, and oparg 0 for ops with no arg.
+        res = []
+        for item in insts:
+            assert isinstance(item, tuple)
+            inst = list(item)
+            opcode = dis.opmap[inst[0]]
+            oparg = inst[1]
+            loc = inst[2:] + [-1] * (6 - len(inst))
+            res.append((opcode, oparg, *loc))
+        return res
+
 
 class CodegenTestCase(CompilationStepTestCase):
 
@@ -118,20 +130,14 @@ def generate_code(self, ast):
 
 class CfgOptimizationTestCase(CompilationStepTestCase):
 
-    def complete_insts_info(self, insts):
-        # fill in omitted fields in location, and oparg 0 for ops with no arg.
-        res = []
-        for item in insts:
-            assert isinstance(item, tuple)
-            inst = list(reversed(item))
-            opcode = dis.opmap[inst.pop()]
-            oparg = inst.pop()
-            loc = inst + [-1] * (4 - len(inst))
-            res.append((opcode, oparg, *loc))
-        return res
-
     def get_optimized(self, insts, consts):
         insts = self.normalize_insts(insts)
         insts = self.complete_insts_info(insts)
         insts = optimize_cfg(insts, consts)
         return insts, consts
+
+class AssemblerTestCase(CompilationStepTestCase):
+
+    def get_code_object(self, filename, insts, metadata):
+        co = assemble_code_object(filename, insts, metadata)
+        return co

Lib/test/test_compiler_assemble.py

@@ -0,0 +1,71 @@
+
+import ast
+import types
+
+from test.support.bytecode_helper import AssemblerTestCase
+
+
+# Tests for the code-object creation stage of the compiler.
+
+class IsolatedAssembleTests(AssemblerTestCase):
+
+    def complete_metadata(self, metadata, filename="myfile.py"):
+        if metadata is None:
+            metadata = {}
+        for key in ['name', 'qualname']:
+            metadata.setdefault(key, key)
+        for key in ['consts']:
+            metadata.setdefault(key, [])
+        for key in ['names', 'varnames', 'cellvars', 'freevars']:
+            metadata.setdefault(key, {})
+        for key in ['argcount', 'posonlyargcount', 'kwonlyargcount']:
+            metadata.setdefault(key, 0)
+        metadata.setdefault('firstlineno', 1)
+        metadata.setdefault('filename', filename)
+        return metadata
+
+    def assemble_test(self, insts, metadata, expected):
+        metadata = self.complete_metadata(metadata)
+        insts = self.complete_insts_info(insts)
+
+        co = self.get_code_object(metadata['filename'], insts, metadata)
+        self.assertIsInstance(co, types.CodeType)
+
+        expected_metadata = {}
+        for key, value in metadata.items():
+            if isinstance(value, list):
+                expected_metadata[key] = tuple(value)
+            elif isinstance(value, dict):
+                expected_metadata[key] = tuple(value.keys())
+            else:
+                expected_metadata[key] = value
+
+        for key, value in expected_metadata.items():
+            self.assertEqual(getattr(co, "co_" + key), value)
+
+        f = types.FunctionType(co, {})
+        for args, res in expected.items():
+            self.assertEqual(f(*args), res)
+
+    def test_simple_expr(self):
+        metadata = {
+            'filename' : 'avg.py',
+            'name'     : 'avg',
+            'qualname' : 'stats.avg',
+            'consts'   : [2],
+            'argcount' : 2,
+            'varnames' : {'x' : 0, 'y' : 1},
+        }
+
+        # code for "return (x+y)/2"
+        insts = [
+            ('RESUME', 0),
+            ('LOAD_FAST', 0, 1),   # 'x'
+            ('LOAD_FAST', 1, 1),   # 'y'
+            ('BINARY_OP', 0, 1),   # '+'
+            ('LOAD_CONST', 0, 1),  # 2
+            ('BINARY_OP', 11, 1),   # '/'
+            ('RETURN_VALUE', 1),
+        ]
+        expected = {(3, 4) : 3.5, (-100, 200) : 50, (10, 18) : 14}
+        self.assemble_test(insts, metadata, expected)

Modules/_testinternalcapi.c

@@ -14,7 +14,7 @@
 #include "Python.h"
 #include "pycore_atomic_funcs.h" // _Py_atomic_int_get()
 #include "pycore_bitutils.h"     // _Py_bswap32()
-#include "pycore_compile.h"      // _PyCompile_CodeGen, _PyCompile_OptimizeCfg
+#include "pycore_compile.h"      // _PyCompile_CodeGen, _PyCompile_OptimizeCfg, _PyCompile_Assemble
 #include "pycore_fileutils.h"    // _Py_normpath
 #include "pycore_frame.h"        // _PyInterpreterFrame
 #include "pycore_gc.h"           // PyGC_Head
@@ -625,6 +625,68 @@ _testinternalcapi_optimize_cfg_impl(PyObject *module, PyObject *instructions,
     return _PyCompile_OptimizeCfg(instructions, consts);
 }
 
+static int
+get_nonnegative_int_from_dict(PyObject *dict, const char *key) {
+    PyObject *obj = PyDict_GetItemString(dict, key);
+    if (obj == NULL) {
+        return -1;
+    }
+    return PyLong_AsLong(obj);
+}
+
+/*[clinic input]
+
+_testinternalcapi.assemble_code_object -> object
+
+  filename: object
+  instructions: object
+  metadata: object
+
+Create a code object for the given instructions.
+[clinic start generated code]*/
+
+static PyObject *
+_testinternalcapi_assemble_code_object_impl(PyObject *module,
+                                            PyObject *filename,
+                                            PyObject *instructions,
+                                            PyObject *metadata)
+/*[clinic end generated code: output=38003dc16a930f48 input=e713ad77f08fb3a8]*/
+
+{
+    assert(PyDict_Check(metadata));
+    _PyCompile_CodeUnitMetadata umd;
+
+    umd.u_name = PyDict_GetItemString(metadata, "name");
+    umd.u_qualname = PyDict_GetItemString(metadata, "qualname");
+
+    assert(PyUnicode_Check(umd.u_name));
+    assert(PyUnicode_Check(umd.u_qualname));
+
+    umd.u_consts = PyDict_GetItemString(metadata, "consts");
+    umd.u_names = PyDict_GetItemString(metadata, "names");
+    umd.u_varnames = PyDict_GetItemString(metadata, "varnames");
+    umd.u_cellvars = PyDict_GetItemString(metadata, "cellvars");
+    umd.u_freevars = PyDict_GetItemString(metadata, "freevars");
+
+    assert(PyList_Check(umd.u_consts));
+    assert(PyDict_Check(umd.u_names));
+    assert(PyDict_Check(umd.u_varnames));
+    assert(PyDict_Check(umd.u_cellvars));
+    assert(PyDict_Check(umd.u_freevars));
+
+    umd.u_argcount = get_nonnegative_int_from_dict(metadata, "argcount");
+    umd.u_posonlyargcount = get_nonnegative_int_from_dict(metadata, "posonlyargcount");
+    umd.u_kwonlyargcount = get_nonnegative_int_from_dict(metadata, "kwonlyargcount");
+    umd.u_firstlineno = get_nonnegative_int_from_dict(metadata, "firstlineno");
+
+    assert(umd.u_argcount >= 0);
+    assert(umd.u_posonlyargcount >= 0);
+    assert(umd.u_kwonlyargcount >= 0);
+    assert(umd.u_firstlineno >= 0);
+
+    return (PyObject*)_PyCompile_Assemble(&umd, filename, instructions);
+}
+
 
 static PyObject *
 get_interp_settings(PyObject *self, PyObject *args)
@@ -705,6 +767,7 @@ static PyMethodDef module_functions[] = {
     {"set_eval_frame_record", set_eval_frame_record, METH_O, NULL},
     _TESTINTERNALCAPI_COMPILER_CODEGEN_METHODDEF
     _TESTINTERNALCAPI_OPTIMIZE_CFG_METHODDEF
+    _TESTINTERNALCAPI_ASSEMBLE_CODE_OBJECT_METHODDEF
     {"get_interp_settings", get_interp_settings, METH_VARARGS, NULL},
     {"clear_extension", clear_extension, METH_VARARGS, NULL},
     {NULL, NULL} /* sentinel */

Modules/clinic/_testinternalcapi.c.h

@@ -128,4 +128,66 @@ _testinternalcapi_optimize_cfg(PyObject *module, PyObject *const *args, Py_ssize
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=efe95836482fd542 input=a9049054013a1b77]*/
+
+PyDoc_STRVAR(_testinternalcapi_assemble_code_object__doc__,
+"assemble_code_object($module, /, filename, instructions, metadata)\n"
+"--\n"
+"\n"
+"Create a code object for the given instructions.");
+
+#define _TESTINTERNALCAPI_ASSEMBLE_CODE_OBJECT_METHODDEF    \
+    {"assemble_code_object", _PyCFunction_CAST(_testinternalcapi_assemble_code_object), METH_FASTCALL|METH_KEYWORDS, _testinternalcapi_assemble_code_object__doc__},
+
+static PyObject *
+_testinternalcapi_assemble_code_object_impl(PyObject *module,
+                                            PyObject *filename,
+                                            PyObject *instructions,
+                                            PyObject *metadata);
+
+static PyObject *
+_testinternalcapi_assemble_code_object(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 3
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(filename), &_Py_ID(instructions), &_Py_ID(metadata), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"filename", "instructions", "metadata", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "assemble_code_object",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[3];
+    PyObject *filename;
+    PyObject *instructions;
+    PyObject *metadata;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 3, 3, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    filename = args[0];
+    instructions = args[1];
+    metadata = args[2];
+    return_value = _testinternalcapi_assemble_code_object_impl(module, filename, instructions, metadata);
+
+exit:
+    return return_value;
+}
+/*[clinic end generated code: output=d5e08c9d67f9721f input=a9049054013a1b77]*/

Python/compile.c

@@ -308,7 +308,6 @@ instr_sequence_fini(instr_sequence *seq) {
     seq->s_instrs = NULL;
 }
 
-
 static int
 instr_sequence_to_cfg(instr_sequence *seq, cfg_builder *g) {
     memset(g, 0, sizeof(cfg_builder));
@@ -6754,11 +6753,11 @@ _PyCompile_ConstCacheMergeOne(PyObject *const_cache, PyObject **obj)
 
 
 static int *
-build_cellfixedoffsets(struct compiler_unit *u)
+build_cellfixedoffsets(_PyCompile_CodeUnitMetadata *umd)
 {
-    int nlocals = (int)PyDict_GET_SIZE(u->u_metadata.u_varnames);
+    int nlocals = (int)PyDict_GET_SIZE(umd->u_varnames);
-    int ncellvars = (int)PyDict_GET_SIZE(u->u_metadata.u_cellvars);
+    int ncellvars = (int)PyDict_GET_SIZE(umd->u_cellvars);
-    int nfreevars = (int)PyDict_GET_SIZE(u->u_metadata.u_freevars);
+    int nfreevars = (int)PyDict_GET_SIZE(umd->u_freevars);
 
     int noffsets = ncellvars + nfreevars;
     int *fixed = PyMem_New(int, noffsets);
@@ -6772,8 +6771,8 @@ build_cellfixedoffsets(struct compiler_unit *u)
 
     PyObject *varname, *cellindex;
     Py_ssize_t pos = 0;
-    while (PyDict_Next(u->u_metadata.u_cellvars, &pos, &varname, &cellindex)) {
+    while (PyDict_Next(umd->u_cellvars, &pos, &varname, &cellindex)) {
-        PyObject *varindex = PyDict_GetItem(u->u_metadata.u_varnames, varname);
+        PyObject *varindex = PyDict_GetItem(umd->u_varnames, varname);
         if (varindex != NULL) {
             assert(PyLong_AS_LONG(cellindex) < INT_MAX);
             assert(PyLong_AS_LONG(varindex) < INT_MAX);
@@ -6787,17 +6786,17 @@ build_cellfixedoffsets(struct compiler_unit *u)
 }
 
 static int
-insert_prefix_instructions(struct compiler_unit *u, basicblock *entryblock,
+insert_prefix_instructions(_PyCompile_CodeUnitMetadata *umd, basicblock *entryblock,
                            int *fixed, int nfreevars, int code_flags)
 {
-    assert(u->u_metadata.u_firstlineno > 0);
+    assert(umd->u_firstlineno > 0);
 
     /* Add the generator prefix instructions. */
     if (code_flags & (CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR)) {
         cfg_instr make_gen = {
             .i_opcode = RETURN_GENERATOR,
             .i_oparg = 0,
-            .i_loc = LOCATION(u->u_metadata.u_firstlineno, u->u_metadata.u_firstlineno, -1, -1),
+            .i_loc = LOCATION(umd->u_firstlineno, umd->u_firstlineno, -1, -1),
             .i_target = NULL,
         };
         RETURN_IF_ERROR(_PyBasicblock_InsertInstruction(entryblock, 0, &make_gen));
@@ -6811,12 +6810,12 @@ insert_prefix_instructions(struct compiler_unit *u, basicblock *entryblock,
     }
 
     /* Set up cells for any variable that escapes, to be put in a closure. */
-    const int ncellvars = (int)PyDict_GET_SIZE(u->u_metadata.u_cellvars);
+    const int ncellvars = (int)PyDict_GET_SIZE(umd->u_cellvars);
     if (ncellvars) {
-        // u->u_metadata.u_cellvars has the cells out of order so we sort them
+        // umd->u_cellvars has the cells out of order so we sort them
         // before adding the MAKE_CELL instructions.  Note that we
         // adjust for arg cells, which come first.
-        const int nvars = ncellvars + (int)PyDict_GET_SIZE(u->u_metadata.u_varnames);
+        const int nvars = ncellvars + (int)PyDict_GET_SIZE(umd->u_varnames);
         int *sorted = PyMem_RawCalloc(nvars, sizeof(int));
         if (sorted == NULL) {
             PyErr_NoMemory();
@@ -6860,11 +6859,11 @@ insert_prefix_instructions(struct compiler_unit *u, basicblock *entryblock,
 }
 
 static int
-fix_cell_offsets(struct compiler_unit *u, basicblock *entryblock, int *fixedmap)
+fix_cell_offsets(_PyCompile_CodeUnitMetadata *umd, basicblock *entryblock, int *fixedmap)
 {
-    int nlocals = (int)PyDict_GET_SIZE(u->u_metadata.u_varnames);
+    int nlocals = (int)PyDict_GET_SIZE(umd->u_varnames);
-    int ncellvars = (int)PyDict_GET_SIZE(u->u_metadata.u_cellvars);
+    int ncellvars = (int)PyDict_GET_SIZE(umd->u_cellvars);
-    int nfreevars = (int)PyDict_GET_SIZE(u->u_metadata.u_freevars);
+    int nfreevars = (int)PyDict_GET_SIZE(umd->u_freevars);
     int noffsets = ncellvars + nfreevars;
 
     // First deal with duplicates (arg cells).
@@ -6906,30 +6905,30 @@ fix_cell_offsets(struct compiler_unit *u, basicblock *entryblock, int *fixedmap)
 
 
 static int
-prepare_localsplus(struct compiler_unit* u, cfg_builder *g, int code_flags)
+prepare_localsplus(_PyCompile_CodeUnitMetadata *umd, cfg_builder *g, int code_flags)
 {
-    assert(PyDict_GET_SIZE(u->u_metadata.u_varnames) < INT_MAX);
+    assert(PyDict_GET_SIZE(umd->u_varnames) < INT_MAX);
-    assert(PyDict_GET_SIZE(u->u_metadata.u_cellvars) < INT_MAX);
+    assert(PyDict_GET_SIZE(umd->u_cellvars) < INT_MAX);
-    assert(PyDict_GET_SIZE(u->u_metadata.u_freevars) < INT_MAX);
+    assert(PyDict_GET_SIZE(umd->u_freevars) < INT_MAX);
-    int nlocals = (int)PyDict_GET_SIZE(u->u_metadata.u_varnames);
+    int nlocals = (int)PyDict_GET_SIZE(umd->u_varnames);
-    int ncellvars = (int)PyDict_GET_SIZE(u->u_metadata.u_cellvars);
+    int ncellvars = (int)PyDict_GET_SIZE(umd->u_cellvars);
-    int nfreevars = (int)PyDict_GET_SIZE(u->u_metadata.u_freevars);
+    int nfreevars = (int)PyDict_GET_SIZE(umd->u_freevars);
     assert(INT_MAX - nlocals - ncellvars > 0);
     assert(INT_MAX - nlocals - ncellvars - nfreevars > 0);
     int nlocalsplus = nlocals + ncellvars + nfreevars;
-    int* cellfixedoffsets = build_cellfixedoffsets(u);
+    int* cellfixedoffsets = build_cellfixedoffsets(umd);
     if (cellfixedoffsets == NULL) {
         return ERROR;
     }
 
 
     // This must be called before fix_cell_offsets().
-    if (insert_prefix_instructions(u, g->g_entryblock, cellfixedoffsets, nfreevars, code_flags)) {
+    if (insert_prefix_instructions(umd, g->g_entryblock, cellfixedoffsets, nfreevars, code_flags)) {
         PyMem_Free(cellfixedoffsets);
         return ERROR;
     }
 
-    int numdropped = fix_cell_offsets(u, g->g_entryblock, cellfixedoffsets);
+    int numdropped = fix_cell_offsets(umd, g->g_entryblock, cellfixedoffsets);
     PyMem_Free(cellfixedoffsets);  // At this point we're done with it.
     cellfixedoffsets = NULL;
     if (numdropped < 0) {
@@ -6980,7 +6979,7 @@ optimize_and_assemble_code_unit(struct compiler_unit *u, PyObject *const_cache,
     }
 
     /** Assembly **/
-    int nlocalsplus = prepare_localsplus(u, &g, code_flags);
+    int nlocalsplus = prepare_localsplus(&u->u_metadata, &g, code_flags);
     if (nlocalsplus < 0) {
         goto error;
     }
@@ -7157,11 +7156,6 @@ instructions_to_instr_sequence(PyObject *instructions, instr_sequence *seq)
             goto error;
         }
     }
-    if (seq->s_used && !IS_TERMINATOR_OPCODE(seq->s_instrs[seq->s_used-1].i_opcode)) {
-        if (instr_sequence_addop(seq, RETURN_VALUE, 0, NO_LOCATION) < 0) {
-            goto error;
-        }
-    }
     PyMem_Free(is_target);
     return SUCCESS;
 error:
@@ -7328,6 +7322,67 @@ _PyCompile_OptimizeCfg(PyObject *instructions, PyObject *consts)
     return res;
 }
 
+int _PyCfg_JumpLabelsToTargets(basicblock *entryblock);
+
+PyCodeObject *
+_PyCompile_Assemble(_PyCompile_CodeUnitMetadata *umd, PyObject *filename,
+                    PyObject *instructions)
+{
+    PyCodeObject *co = NULL;
+    instr_sequence optimized_instrs;
+    memset(&optimized_instrs, 0, sizeof(instr_sequence));
+
+    PyObject *const_cache = PyDict_New();
+    if (const_cache == NULL) {
+        return NULL;
+    }
+
+    cfg_builder g;
+    if (instructions_to_cfg(instructions, &g) < 0) {
+        goto error;
+    }
+
+    if (_PyCfg_JumpLabelsToTargets(g.g_entryblock) < 0) {
+        goto error;
+    }
+
+    int code_flags = 0;
+    int nlocalsplus = prepare_localsplus(umd, &g, code_flags);
+    if (nlocalsplus < 0) {
+        goto error;
+    }
+
+    int maxdepth = _PyCfg_Stackdepth(g.g_entryblock, code_flags);
+    if (maxdepth < 0) {
+        goto error;
+    }
+
+    _PyCfg_ConvertExceptionHandlersToNops(g.g_entryblock);
+
+    /* Order of basic blocks must have been determined by now */
+
+    if (_PyCfg_ResolveJumps(&g) < 0) {
+        goto error;
+    }
+
+    /* Can't modify the bytecode after computing jump offsets. */
+
+    if (cfg_to_instr_sequence(&g, &optimized_instrs) < 0) {
+        goto error;
+    }
+
+    PyObject *consts = umd->u_consts;
+    co = _PyAssemble_MakeCodeObject(umd, const_cache,
+                                    consts, maxdepth, &optimized_instrs,
+                                    nlocalsplus, code_flags, filename);
+
+error:
+    Py_DECREF(const_cache);
+    _PyCfgBuilder_Fini(&g);
+    instr_sequence_fini(&optimized_instrs);
+    return co;
+}
+
 
 /* Retained for API compatibility.
  * Optimization is now done in _PyCfg_OptimizeCodeUnit */

Python/flowgraph.c

@@ -223,6 +223,15 @@ dump_basicblock(const basicblock *b)
         }
     }
 }
+
+void
+_PyCfgBuilder_DumpGraph(const basicblock *entryblock)
+{
+    for (const basicblock *b = entryblock; b != NULL; b = b->b_next) {
+        dump_basicblock(b);
+    }
+}
+
 #endif
 
 
@@ -592,6 +601,11 @@ translate_jump_labels_to_targets(basicblock *entryblock)
     return SUCCESS;
 }
 
+int
+_PyCfg_JumpLabelsToTargets(basicblock *entryblock)
+{
+    return translate_jump_labels_to_targets(entryblock);
+}
 
 static int
 mark_except_handlers(basicblock *entryblock) {