gh-117680: make _PyInstructionSequence a PyObject and use it in tests (#117629)

17 files changed, 838 insertions, 242 deletions

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index 24f32fc..90a338a 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -864,6 +864,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(co_stacksize));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(co_varnames));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(code));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(col_offset));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(command));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(comment_factory));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(compile_mode));
@@ -913,6 +914,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(encode));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(encoding));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(end));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(end_col_offset));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(end_lineno));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(end_offset));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(endpos));
@@ -1033,6 +1035,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(kw1));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(kw2));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(kwdefaults));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(label));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(lambda));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(last));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(last_exc));
@@ -1096,6 +1099,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(namespaces));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(narg));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(ndigits));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(nested));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(new_file_name));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(new_limit));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(newline));
diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index 024f817..0899e7e 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -353,6 +353,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(co_stacksize)
         STRUCT_FOR_ID(co_varnames)
         STRUCT_FOR_ID(code)
+        STRUCT_FOR_ID(col_offset)
         STRUCT_FOR_ID(command)
         STRUCT_FOR_ID(comment_factory)
         STRUCT_FOR_ID(compile_mode)
@@ -402,6 +403,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(encode)
         STRUCT_FOR_ID(encoding)
         STRUCT_FOR_ID(end)
+        STRUCT_FOR_ID(end_col_offset)
         STRUCT_FOR_ID(end_lineno)
         STRUCT_FOR_ID(end_offset)
         STRUCT_FOR_ID(endpos)
@@ -522,6 +524,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(kw1)
         STRUCT_FOR_ID(kw2)
         STRUCT_FOR_ID(kwdefaults)
+        STRUCT_FOR_ID(label)
         STRUCT_FOR_ID(lambda)
         STRUCT_FOR_ID(last)
         STRUCT_FOR_ID(last_exc)
@@ -585,6 +588,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(namespaces)
         STRUCT_FOR_ID(narg)
         STRUCT_FOR_ID(ndigits)
+        STRUCT_FOR_ID(nested)
         STRUCT_FOR_ID(new_file_name)
         STRUCT_FOR_ID(new_limit)
         STRUCT_FOR_ID(newline)
diff --git a/Include/internal/pycore_instruction_sequence.h b/Include/internal/pycore_instruction_sequence.h
index b57484f..ecba0d9 100644
--- a/Include/internal/pycore_instruction_sequence.h
+++ b/Include/internal/pycore_instruction_sequence.h
@@ -5,10 +5,13 @@
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+#include "pycore_symtable.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+
 typedef struct {
     int h_label;
     int h_startdepth;
@@ -26,23 +29,30 @@ typedef struct {
     int i_offset;
 } _PyInstruction;
 
-typedef struct {
+typedef struct instruction_sequence {
+    PyObject_HEAD
     _PyInstruction *s_instrs;
     int s_allocated;
     int s_used;
 
     int s_next_free_label; /* next free label id */
+
     /* Map of a label id to instruction offset (index into s_instrs).
      * If s_labelmap is NULL, then each label id is the offset itself.
      */
-    int *s_labelmap;       /* label id --> instr offset */
+    int *s_labelmap;
     int s_labelmap_size;
+
+    /* PyList of instruction sequences of nested functions */
+    PyObject *s_nested;
 } _PyInstructionSequence;
 
 typedef struct {
     int id;
 } _PyJumpTargetLabel;
 
+PyAPI_FUNC(PyObject*)_PyInstructionSequence_New(void);
+
 int _PyInstructionSequence_UseLabel(_PyInstructionSequence *seq, int lbl);
 int _PyInstructionSequence_Addop(_PyInstructionSequence *seq,
                                  int opcode, int oparg,
@@ -53,6 +63,8 @@ int _PyInstructionSequence_InsertInstruction(_PyInstructionSequence *seq, int po
                                              int opcode, int oparg, _Py_SourceLocation loc);
 void PyInstructionSequence_Fini(_PyInstructionSequence *seq);
 
+extern PyTypeObject _PyInstructionSequence_Type;
+#define _PyInstructionSequence_Check(v) Py_IS_TYPE((v), &_PyInstructionSequence_Type)
 
 #ifdef __cplusplus
 }
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index 795f95c..d4323e5 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -862,6 +862,7 @@ extern "C" {
     INIT_ID(co_stacksize), \
     INIT_ID(co_varnames), \
     INIT_ID(code), \
+    INIT_ID(col_offset), \
     INIT_ID(command), \
     INIT_ID(comment_factory), \
     INIT_ID(compile_mode), \
@@ -911,6 +912,7 @@ extern "C" {
     INIT_ID(encode), \
     INIT_ID(encoding), \
     INIT_ID(end), \
+    INIT_ID(end_col_offset), \
     INIT_ID(end_lineno), \
     INIT_ID(end_offset), \
     INIT_ID(endpos), \
@@ -1031,6 +1033,7 @@ extern "C" {
     INIT_ID(kw1), \
     INIT_ID(kw2), \
     INIT_ID(kwdefaults), \
+    INIT_ID(label), \
     INIT_ID(lambda), \
     INIT_ID(last), \
     INIT_ID(last_exc), \
@@ -1094,6 +1097,7 @@ extern "C" {
     INIT_ID(namespaces), \
     INIT_ID(narg), \
     INIT_ID(ndigits), \
+    INIT_ID(nested), \
     INIT_ID(new_file_name), \
     INIT_ID(new_limit), \
     INIT_ID(newline), \
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index 272462e..9daef26 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -900,6 +900,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(code);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(col_offset);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(command);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1047,6 +1050,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(end);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(end_col_offset);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(end_lineno);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1407,6 +1413,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(kwdefaults);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(label);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(lambda);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1596,6 +1605,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(ndigits);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(nested);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(new_file_name);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
diff --git a/Lib/test/support/bytecode_helper.py b/Lib/test/support/bytecode_helper.py
index 7a0e884..85bcd1f 100644
--- a/Lib/test/support/bytecode_helper.py
+++ b/Lib/test/support/bytecode_helper.py
@@ -3,6 +3,7 @@
 import unittest
 import dis
 import io
+import opcode
 try:
     import _testinternalcapi
 except ImportError:
@@ -68,16 +69,14 @@ class CompilationStepTestCase(unittest.TestCase):
     class Label:
         pass
 
-    def assertInstructionsMatch(self, actual_, expected_):
-        # get two lists where each entry is a label or
-        # an instruction tuple. Normalize the labels to the
-        # instruction count of the target, and compare the lists.
+    def assertInstructionsMatch(self, actual_seq, expected):
+        # get an InstructionSequence and an expected list, where each
+        # entry is a label or an instruction tuple. Construct an expcted
+        # instruction sequence and compare with the one given.
 
-        self.assertIsInstance(actual_, list)
-        self.assertIsInstance(expected_, list)
-
-        actual = self.normalize_insts(actual_)
-        expected = self.normalize_insts(expected_)
+        self.assertIsInstance(expected, list)
+        actual = actual_seq.get_instructions()
+        expected = self.seq_from_insts(expected).get_instructions()
         self.assertEqual(len(actual), len(expected))
 
         # compare instructions
@@ -87,10 +86,8 @@ class CompilationStepTestCase(unittest.TestCase):
                 continue
             self.assertIsInstance(exp, tuple)
             self.assertIsInstance(act, tuple)
-            # crop comparison to the provided expected values
-            if len(act) > len(exp):
-                act = act[:len(exp)]
-            self.assertEqual(exp, act)
+            idx = max([p[0] for p in enumerate(exp) if p[1] != -1])
+            self.assertEqual(exp[:idx], act[:idx])
 
     def resolveAndRemoveLabels(self, insts):
         idx = 0
@@ -105,35 +102,37 @@ class CompilationStepTestCase(unittest.TestCase):
 
         return res
 
-    def normalize_insts(self, insts):
-        """ Map labels to instruction index.
-            Map opcodes to opnames.
-        """
-        insts = self.resolveAndRemoveLabels(insts)
-        res = []
-        for item in insts:
-            assert isinstance(item, tuple)
-            opcode, oparg, *loc = item
-            opcode = dis.opmap.get(opcode, opcode)
-            if isinstance(oparg, self.Label):
-                arg = oparg.value
-            else:
-                arg = oparg if opcode in self.HAS_ARG else None
-            opcode = dis.opname[opcode]
-            res.append((opcode, arg, *loc))
-        return res
+    def seq_from_insts(self, insts):
+        labels = {item for item in insts if isinstance(item, self.Label)}
+        for i, lbl in enumerate(labels):
+            lbl.value = i
 
-    def complete_insts_info(self, insts):
-        # fill in omitted fields in location, and oparg 0 for ops with no arg.
-        res = []
+        seq = _testinternalcapi.new_instruction_sequence()
         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
+            if isinstance(item, self.Label):
+                seq.use_label(item.value)
+            else:
+                op = item[0]
+                if isinstance(op, str):
+                    op = opcode.opmap[op]
+                arg, *loc = item[1:]
+                if isinstance(arg, self.Label):
+                    arg = arg.value
+                loc = loc + [-1] * (4 - len(loc))
+                seq.addop(op, arg or 0, *loc)
+        return seq
+
+    def check_instructions(self, insts):
+        for inst in insts:
+            if isinstance(inst, self.Label):
+                continue
+            op, arg, *loc = inst
+            if isinstance(op, str):
+                op = opcode.opmap[op]
+            self.assertEqual(op in opcode.hasarg,
+                             arg is not None,
+                             f"{opcode.opname[op]=} {arg=}")
+            self.assertTrue(all(isinstance(l, int) for l in loc))
 
 
 @unittest.skipIf(_testinternalcapi is None, "requires _testinternalcapi")
@@ -147,10 +146,8 @@ class CodegenTestCase(CompilationStepTestCase):
 @unittest.skipIf(_testinternalcapi is None, "requires _testinternalcapi")
 class CfgOptimizationTestCase(CompilationStepTestCase):
 
-    def get_optimized(self, insts, consts, nlocals=0):
-        insts = self.normalize_insts(insts)
-        insts = self.complete_insts_info(insts)
-        insts = _testinternalcapi.optimize_cfg(insts, consts, nlocals)
+    def get_optimized(self, seq, consts, nlocals=0):
+        insts = _testinternalcapi.optimize_cfg(seq, consts, nlocals)
         return insts, consts
 
 @unittest.skipIf(_testinternalcapi is None, "requires _testinternalcapi")
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index 638b6e9..484d72e 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -2,6 +2,7 @@ import contextlib
 import dis
 import io
 import math
+import opcode
 import os
 import unittest
 import sys
@@ -11,6 +12,8 @@ import tempfile
 import types
 import textwrap
 import warnings
+import _testinternalcapi
+
 from test import support
 from test.support import (script_helper, requires_debug_ranges,
                           requires_specialization, get_c_recursion_limit)
@@ -2419,6 +2422,49 @@ class TestStackSizeStability(unittest.TestCase):
             """
         self.check_stack_size(snippet, async_=True)
 
+class TestInstructionSequence(unittest.TestCase):
+    def compare_instructions(self, seq, expected):
+        self.assertEqual([(opcode.opname[i[0]],) + i[1:] for i in seq.get_instructions()],
+                         expected)
+
+    def test_basics(self):
+        seq = _testinternalcapi.new_instruction_sequence()
+
+        def add_op(seq, opname, oparg, bl, bc=0, el=0, ec=0):
+            seq.addop(opcode.opmap[opname], oparg, bl, bc, el, el)
+
+        add_op(seq, 'LOAD_CONST', 1, 1)
+        add_op(seq, 'JUMP', lbl1 := seq.new_label(), 2)
+        add_op(seq, 'LOAD_CONST', 1, 3)
+        add_op(seq, 'JUMP', lbl2 := seq.new_label(), 4)
+        seq.use_label(lbl1)
+        add_op(seq, 'LOAD_CONST', 2, 4)
+        seq.use_label(lbl2)
+        add_op(seq, 'RETURN_VALUE', 0, 3)
+
+        expected = [('LOAD_CONST', 1, 1),
+                    ('JUMP', 4, 2),
+                    ('LOAD_CONST', 1, 3),
+                    ('JUMP', 5, 4),
+                    ('LOAD_CONST', 2, 4),
+                    ('RETURN_VALUE', None, 3),
+                   ]
+
+        self.compare_instructions(seq, [ex + (0,0,0) for ex in expected])
+
+    def test_nested(self):
+        seq = _testinternalcapi.new_instruction_sequence()
+        seq.addop(opcode.opmap['LOAD_CONST'], 1, 1, 0, 0, 0)
+        nested = _testinternalcapi.new_instruction_sequence()
+        nested.addop(opcode.opmap['LOAD_CONST'], 2, 2, 0, 0, 0)
+
+        self.compare_instructions(seq, [('LOAD_CONST', 1, 1, 0, 0, 0)])
+        self.compare_instructions(nested, [('LOAD_CONST', 2, 2, 0, 0, 0)])
+
+        seq.add_nested(nested)
+        self.compare_instructions(seq, [('LOAD_CONST', 1, 1, 0, 0, 0)])
+        self.compare_instructions(seq.get_nested()[0], [('LOAD_CONST', 2, 2, 0, 0, 0)])
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Lib/test/test_compiler_assemble.py b/Lib/test/test_compiler_assemble.py
index ab9f04d..1b98b0d 100644
--- a/Lib/test/test_compiler_assemble.py
+++ b/Lib/test/test_compiler_assemble.py
@@ -27,8 +27,8 @@ class IsolatedAssembleTests(AssemblerTestCase):
 
     def insts_to_code_object(self, insts, metadata):
         metadata = self.complete_metadata(metadata)
-        insts = self.complete_insts_info(insts)
-        return self.get_code_object(metadata['filename'], insts, metadata)
+        seq = self.seq_from_insts(insts)
+        return self.get_code_object(metadata['filename'], seq, metadata)
 
     def assemble_test(self, insts, metadata, expected):
         co = self.insts_to_code_object(insts, metadata)
@@ -71,7 +71,7 @@ class IsolatedAssembleTests(AssemblerTestCase):
             ('BINARY_OP', 0, 1),   # '+'
             ('LOAD_CONST', 0, 1),  # 2
             ('BINARY_OP', 11, 1),   # '/'
-            ('RETURN_VALUE', 1),
+            ('RETURN_VALUE', None, 1),
         ]
         expected = {(3, 4) : 3.5, (-100, 200) : 50, (10, 18) : 14}
         self.assemble_test(insts, metadata, expected)
@@ -102,13 +102,13 @@ class IsolatedAssembleTests(AssemblerTestCase):
             ('LOAD_CLOSURE', 0, 1),
             ('BUILD_TUPLE', 1, 1),
             ('LOAD_CONST', 1, 1),
-            ('MAKE_FUNCTION', 0, 2),
+            ('MAKE_FUNCTION', None, 2),
             ('SET_FUNCTION_ATTRIBUTE', 8, 2),
-            ('PUSH_NULL', 0, 1),
+            ('PUSH_NULL', None, 1),
             ('CALL', 0, 2),                     # (lambda: x)()
             ('LOAD_CONST', 2, 2),               # 2
             ('BINARY_OP', 6, 2),                # %
-            ('RETURN_VALUE', 0, 2)
+            ('RETURN_VALUE', None, 2)
         ]
 
         expected = {(0,): 0, (1,): 1, (2,): 0, (120,): 0, (121,): 1}
@@ -128,12 +128,12 @@ class IsolatedAssembleTests(AssemblerTestCase):
             ('SETUP_FINALLY', 3),
             ('RETURN_CONST', 0),
             ('SETUP_CLEANUP', 8),
-            ('PUSH_EXC_INFO', 0),
-            ('POP_TOP', 0),
-            ('POP_EXCEPT', 0),
+            ('PUSH_EXC_INFO', None),
+            ('POP_TOP', None),
+            ('POP_EXCEPT', None),
             ('RETURN_CONST', 0),
             ('COPY', 3),
-            ('POP_EXCEPT', 0),
+            ('POP_EXCEPT', None),
             ('RERAISE', 1),
         ]
         co = self.insts_to_code_object(insts, metadata)
diff --git a/Lib/test/test_peepholer.py b/Lib/test/test_peepholer.py
index dffedd0..6989aaf 100644
--- a/Lib/test/test_peepholer.py
+++ b/Lib/test/test_peepholer.py
@@ -1,5 +1,6 @@
 import dis
 from itertools import combinations, product
+import opcode
 import sys
 import textwrap
 import unittest
@@ -981,10 +982,15 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
     def cfg_optimization_test(self, insts, expected_insts,
                               consts=None, expected_consts=None,
                               nlocals=0):
+
+        self.check_instructions(insts)
+        self.check_instructions(expected_insts)
+
         if expected_consts is None:
             expected_consts = consts
-        opt_insts, opt_consts = self.get_optimized(insts, consts, nlocals)
-        expected_insts = self.normalize_insts(expected_insts)
+        seq = self.seq_from_insts(insts)
+        opt_insts, opt_consts = self.get_optimized(seq, consts, nlocals)
+        expected_insts = self.seq_from_insts(expected_insts).get_instructions()
         self.assertInstructionsMatch(opt_insts, expected_insts)
         self.assertEqual(opt_consts, expected_consts)
 
@@ -993,10 +999,10 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('LOAD_NAME', 1, 11),
             ('POP_JUMP_IF_TRUE', lbl := self.Label(), 12),
             ('LOAD_CONST', 2, 13),
-            ('RETURN_VALUE', 13),
+            ('RETURN_VALUE', None, 13),
             lbl,
             ('LOAD_CONST', 3, 14),
-            ('RETURN_VALUE', 14),
+            ('RETURN_VALUE', None, 14),
         ]
         expected_insts = [
             ('LOAD_NAME', 1, 11),
@@ -1020,11 +1026,11 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('LOAD_CONST', 2, 13),
             lbl,
             ('LOAD_CONST', 3, 14),
-            ('RETURN_VALUE', 14),
+            ('RETURN_VALUE', None, 14),
         ]
         expected_insts = [
-            ('NOP', 11),
-            ('NOP', 12),
+            ('NOP', None, 11),
+            ('NOP', None, 12),
             ('RETURN_CONST', 1, 14),
         ]
         self.cfg_optimization_test(insts,
@@ -1038,14 +1044,14 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('LOAD_NAME', 1, 11),
             ('POP_JUMP_IF_TRUE', lbl1, 12),
             ('LOAD_NAME', 2, 13),
-            ('RETURN_VALUE', 13),
+            ('RETURN_VALUE', None, 13),
         ]
         expected = [
             lbl := self.Label(),
             ('LOAD_NAME', 1, 11),
             ('POP_JUMP_IF_TRUE', lbl, 12),
             ('LOAD_NAME', 2, 13),
-            ('RETURN_VALUE', 13),
+            ('RETURN_VALUE', None, 13),
         ]
         self.cfg_optimization_test(insts, expected, consts=list(range(5)))
 
@@ -1056,11 +1062,11 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('LOAD_CONST', 3, 11),
             ('POP_JUMP_IF_TRUE', lbl1, 12),
             ('LOAD_CONST', 2, 13),
-            ('RETURN_VALUE', 13),
+            ('RETURN_VALUE', None, 13),
         ]
         expected_insts = [
             lbl := self.Label(),
-            ('NOP', 11),
+            ('NOP', None, 11),
             ('JUMP', lbl, 12),
         ]
         self.cfg_optimization_test(insts, expected_insts, consts=list(range(5)))
@@ -1068,7 +1074,7 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
     def test_except_handler_label(self):
         insts = [
             ('SETUP_FINALLY', handler := self.Label(), 10),
-            ('POP_BLOCK', 0, -1),
+            ('POP_BLOCK', None, -1),
             ('RETURN_CONST', 1, 11),
             handler,
             ('RETURN_CONST', 2, 12),
@@ -1090,16 +1096,16 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('SWAP', 3, 4),
             ('STORE_FAST', 1, 4),
             ('STORE_FAST', 1, 4),
-            ('POP_TOP', 0, 4),
+            ('POP_TOP', None, 4),
             ('LOAD_CONST', 0, 5),
-            ('RETURN_VALUE', 5)
+            ('RETURN_VALUE', None, 5)
         ]
         expected_insts = [
             ('LOAD_CONST', 0, 1),
             ('LOAD_CONST', 1, 2),
-            ('NOP', 0, 3),
+            ('NOP', None, 3),
             ('STORE_FAST', 1, 4),
-            ('POP_TOP', 0, 4),
+            ('POP_TOP', None, 4),
             ('RETURN_CONST', 0)
         ]
         self.cfg_optimization_test(insts, expected_insts, consts=list(range(3)), nlocals=1)
@@ -1113,13 +1119,13 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('STORE_FAST', 1, 4),
             ('STORE_FAST', 1, 4),
             ('LOAD_CONST', 0, 5),
-            ('RETURN_VALUE', 5)
+            ('RETURN_VALUE', None, 5)
         ]
         expected_insts = [
             ('LOAD_CONST', 0, 1),
             ('LOAD_CONST', 1, 2),
-            ('NOP', 0, 3),
-            ('POP_TOP', 0, 4),
+            ('NOP', None, 3),
+            ('POP_TOP', None, 4),
             ('STORE_FAST', 1, 4),
             ('RETURN_CONST', 0, 5)
         ]
@@ -1134,7 +1140,7 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
             ('STORE_FAST', 1, 5),
             ('STORE_FAST', 1, 6),
             ('LOAD_CONST', 0, 5),
-            ('RETURN_VALUE', 5)
+            ('RETURN_VALUE', None, 5)
         ]
         expected_insts = [
             ('LOAD_CONST', 0, 1),
@@ -1169,7 +1175,7 @@ class DirectCfgOptimizerTests(CfgOptimizationTestCase):
                     op = 'JUMP' if 'JUMP' in (op1, op2) else 'JUMP_NO_INTERRUPT'
                     expected_insts = [
                         ('LOAD_NAME', 0, 10),
-                        ('NOP', 0, 4),
+                        ('NOP', None, 4),
                         (op, 0, 5),
                     ]
                     self.cfg_optimization_test(insts, expected_insts, consts=list(range(5)))
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-04-09-16-07-00.gh-issue-117680.MRZ78K.rst b/Misc/NEWS.d/next/Core and Builtins/2024-04-09-16-07-00.gh-issue-117680.MRZ78K.rst
new file mode 100644
index 0000000..fd437b7
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2024-04-09-16-07-00.gh-issue-117680.MRZ78K.rst
@@ -0,0 +1 @@
+Give ``_PyInstructionSequence`` a Python interface and use it in tests.
diff --git a/Modules/_testinternalcapi.c b/Modules/_testinternalcapi.c
index 36dad02..cc9e140 100644
--- a/Modules/_testinternalcapi.c
+++ b/Modules/_testinternalcapi.c
@@ -22,6 +22,7 @@
 #include "pycore_gc.h"            // PyGC_Head
 #include "pycore_hashtable.h"     // _Py_hashtable_new()
 #include "pycore_initconfig.h"    // _Py_GetConfigsAsDict()
+#include "pycore_instruction_sequence.h"  // _PyInstructionSequence_New()
 #include "pycore_interp.h"        // _PyInterpreterState_GetConfigCopy()
 #include "pycore_long.h"          // _PyLong_Sign()
 #include "pycore_object.h"        // _PyObject_IsFreed()
@@ -723,6 +724,19 @@ _testinternalcapi_compiler_cleandoc_impl(PyObject *module, PyObject *doc)
     return _PyCompile_CleanDoc(doc);
 }
 
+/*[clinic input]
+
+_testinternalcapi.new_instruction_sequence -> object
+
+Return a new, empty InstructionSequence.
+[clinic start generated code]*/
+
+static PyObject *
+_testinternalcapi_new_instruction_sequence_impl(PyObject *module)
+/*[clinic end generated code: output=ea4243fddb9057fd input=1dec2591b173be83]*/
+{
+    return _PyInstructionSequence_New();
+}
 
 /*[clinic input]
 
@@ -1952,6 +1966,7 @@ static PyMethodDef module_functions[] = {
     {"set_eval_frame_default", set_eval_frame_default, METH_NOARGS, NULL},
     {"set_eval_frame_record", set_eval_frame_record, METH_O, NULL},
     _TESTINTERNALCAPI_COMPILER_CLEANDOC_METHODDEF
+    _TESTINTERNALCAPI_NEW_INSTRUCTION_SEQUENCE_METHODDEF
     _TESTINTERNALCAPI_COMPILER_CODEGEN_METHODDEF
     _TESTINTERNALCAPI_OPTIMIZE_CFG_METHODDEF
     _TESTINTERNALCAPI_ASSEMBLE_CODE_OBJECT_METHODDEF
diff --git a/Modules/clinic/_testinternalcapi.c.h b/Modules/clinic/_testinternalcapi.c.h
index cba2a94..a618585 100644
--- a/Modules/clinic/_testinternalcapi.c.h
+++ b/Modules/clinic/_testinternalcapi.c.h
@@ -67,6 +67,24 @@ exit:
     return return_value;
 }
 
+PyDoc_STRVAR(_testinternalcapi_new_instruction_sequence__doc__,
+"new_instruction_sequence($module, /)\n"
+"--\n"
+"\n"
+"Return a new, empty InstructionSequence.");
+
+#define _TESTINTERNALCAPI_NEW_INSTRUCTION_SEQUENCE_METHODDEF    \
+    {"new_instruction_sequence", (PyCFunction)_testinternalcapi_new_instruction_sequence, METH_NOARGS, _testinternalcapi_new_instruction_sequence__doc__},
+
+static PyObject *
+_testinternalcapi_new_instruction_sequence_impl(PyObject *module);
+
+static PyObject *
+_testinternalcapi_new_instruction_sequence(PyObject *module, PyObject *Py_UNUSED(ignored))
+{
+    return _testinternalcapi_new_instruction_sequence_impl(module);
+}
+
 PyDoc_STRVAR(_testinternalcapi_compiler_codegen__doc__,
 "compiler_codegen($module, /, ast, filename, optimize, compile_mode=0)\n"
 "--\n"
@@ -282,4 +300,4 @@ _testinternalcapi_test_long_numbits(PyObject *module, PyObject *Py_UNUSED(ignore
 {
     return _testinternalcapi_test_long_numbits_impl(module);
 }
-/*[clinic end generated code: output=679bf53bbae20085 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=9804015d77d36c77 input=a9049054013a1b77]*/
diff --git a/Objects/object.c b/Objects/object.c
index 3830db0..214e7c5 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -10,6 +10,7 @@
 #include "pycore_dict.h"          // _PyObject_MakeDictFromInstanceAttributes()
 #include "pycore_floatobject.h"   // _PyFloat_DebugMallocStats()
 #include "pycore_initconfig.h"    // _PyStatus_EXCEPTION()
+#include "pycore_instruction_sequence.h" // _PyInstructionSequence_Type
 #include "pycore_hashtable.h"     // _Py_hashtable_new()
 #include "pycore_memoryobject.h"  // _PyManagedBuffer_Type
 #include "pycore_namespace.h"     // _PyNamespace_Type
@@ -2294,6 +2295,7 @@ static PyTypeObject* static_types[] = {
     &_PyHamt_BitmapNode_Type,
     &_PyHamt_CollisionNode_Type,
     &_PyHamt_Type,
+    &_PyInstructionSequence_Type,
     &_PyLegacyEventHandler_Type,
     &_PyLineIterator,
     &_PyManagedBuffer_Type,
diff --git a/Python/clinic/instruction_sequence.c.h b/Python/clinic/instruction_sequence.c.h
new file mode 100644
index 0000000..66c2cca
--- /dev/null
+++ b/Python/clinic/instruction_sequence.c.h
@@ -0,0 +1,304 @@
+/*[clinic input]
+preserve
+[clinic start generated code]*/
+
+#if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+#  include "pycore_gc.h"          // PyGC_Head
+#  include "pycore_runtime.h"     // _Py_ID()
+#endif
+#include "pycore_modsupport.h"    // _PyArg_NoKeywords()
+
+PyDoc_STRVAR(inst_seq_new__doc__,
+"InstructionSequenceType()\n"
+"--\n"
+"\n"
+"Create a new InstructionSequence object.");
+
+static PyObject *
+inst_seq_new_impl(PyTypeObject *type);
+
+static PyObject *
+inst_seq_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    PyTypeObject *base_tp = &_PyInstructionSequence_Type;
+
+    if ((type == base_tp || type->tp_init == base_tp->tp_init) &&
+        !_PyArg_NoPositional("InstructionSequenceType", args)) {
+        goto exit;
+    }
+    if ((type == base_tp || type->tp_init == base_tp->tp_init) &&
+        !_PyArg_NoKeywords("InstructionSequenceType", kwargs)) {
+        goto exit;
+    }
+    return_value = inst_seq_new_impl(type);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(InstructionSequenceType_use_label__doc__,
+"use_label($self, /, label)\n"
+"--\n"
+"\n"
+"Place label at current location.");
+
+#define INSTRUCTIONSEQUENCETYPE_USE_LABEL_METHODDEF    \
+    {"use_label", _PyCFunction_CAST(InstructionSequenceType_use_label), METH_FASTCALL|METH_KEYWORDS, InstructionSequenceType_use_label__doc__},
+
+static PyObject *
+InstructionSequenceType_use_label_impl(_PyInstructionSequence *self,
+                                       int label);
+
+static PyObject *
+InstructionSequenceType_use_label(_PyInstructionSequence *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(label), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"label", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "use_label",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    int label;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    label = PyLong_AsInt(args[0]);
+    if (label == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    return_value = InstructionSequenceType_use_label_impl(self, label);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(InstructionSequenceType_addop__doc__,
+"addop($self, /, opcode, oparg, lineno, col_offset, end_lineno,\n"
+"      end_col_offset)\n"
+"--\n"
+"\n"
+"Append an instruction.");
+
+#define INSTRUCTIONSEQUENCETYPE_ADDOP_METHODDEF    \
+    {"addop", _PyCFunction_CAST(InstructionSequenceType_addop), METH_FASTCALL|METH_KEYWORDS, InstructionSequenceType_addop__doc__},
+
+static PyObject *
+InstructionSequenceType_addop_impl(_PyInstructionSequence *self, int opcode,
+                                   int oparg, int lineno, int col_offset,
+                                   int end_lineno, int end_col_offset);
+
+static PyObject *
+InstructionSequenceType_addop(_PyInstructionSequence *self, 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 6
+    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(opcode), &_Py_ID(oparg), &_Py_ID(lineno), &_Py_ID(col_offset), &_Py_ID(end_lineno), &_Py_ID(end_col_offset), },
+    };
+    #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[] = {"opcode", "oparg", "lineno", "col_offset", "end_lineno", "end_col_offset", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "addop",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[6];
+    int opcode;
+    int oparg;
+    int lineno;
+    int col_offset;
+    int end_lineno;
+    int end_col_offset;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 6, 6, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    opcode = PyLong_AsInt(args[0]);
+    if (opcode == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    oparg = PyLong_AsInt(args[1]);
+    if (oparg == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    lineno = PyLong_AsInt(args[2]);
+    if (lineno == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    col_offset = PyLong_AsInt(args[3]);
+    if (col_offset == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    end_lineno = PyLong_AsInt(args[4]);
+    if (end_lineno == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    end_col_offset = PyLong_AsInt(args[5]);
+    if (end_col_offset == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+    return_value = InstructionSequenceType_addop_impl(self, opcode, oparg, lineno, col_offset, end_lineno, end_col_offset);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(InstructionSequenceType_new_label__doc__,
+"new_label($self, /)\n"
+"--\n"
+"\n"
+"Return a new label.");
+
+#define INSTRUCTIONSEQUENCETYPE_NEW_LABEL_METHODDEF    \
+    {"new_label", (PyCFunction)InstructionSequenceType_new_label, METH_NOARGS, InstructionSequenceType_new_label__doc__},
+
+static int
+InstructionSequenceType_new_label_impl(_PyInstructionSequence *self);
+
+static PyObject *
+InstructionSequenceType_new_label(_PyInstructionSequence *self, PyObject *Py_UNUSED(ignored))
+{
+    PyObject *return_value = NULL;
+    int _return_value;
+
+    _return_value = InstructionSequenceType_new_label_impl(self);
+    if ((_return_value == -1) && PyErr_Occurred()) {
+        goto exit;
+    }
+    return_value = PyLong_FromLong((long)_return_value);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(InstructionSequenceType_add_nested__doc__,
+"add_nested($self, /, nested)\n"
+"--\n"
+"\n"
+"Add a nested sequence.");
+
+#define INSTRUCTIONSEQUENCETYPE_ADD_NESTED_METHODDEF    \
+    {"add_nested", _PyCFunction_CAST(InstructionSequenceType_add_nested), METH_FASTCALL|METH_KEYWORDS, InstructionSequenceType_add_nested__doc__},
+
+static PyObject *
+InstructionSequenceType_add_nested_impl(_PyInstructionSequence *self,
+                                        PyObject *nested);
+
+static PyObject *
+InstructionSequenceType_add_nested(_PyInstructionSequence *self, 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 1
+    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(nested), },
+    };
+    #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[] = {"nested", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "add_nested",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject *nested;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    nested = args[0];
+    return_value = InstructionSequenceType_add_nested_impl(self, nested);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(InstructionSequenceType_get_nested__doc__,
+"get_nested($self, /)\n"
+"--\n"
+"\n"
+"Add a nested sequence.");
+
+#define INSTRUCTIONSEQUENCETYPE_GET_NESTED_METHODDEF    \
+    {"get_nested", (PyCFunction)InstructionSequenceType_get_nested, METH_NOARGS, InstructionSequenceType_get_nested__doc__},
+
+static PyObject *
+InstructionSequenceType_get_nested_impl(_PyInstructionSequence *self);
+
+static PyObject *
+InstructionSequenceType_get_nested(_PyInstructionSequence *self, PyObject *Py_UNUSED(ignored))
+{
+    return InstructionSequenceType_get_nested_impl(self);
+}
+
+PyDoc_STRVAR(InstructionSequenceType_get_instructions__doc__,
+"get_instructions($self, /)\n"
+"--\n"
+"\n"
+"Return the instructions as a list of tuples or labels.");
+
+#define INSTRUCTIONSEQUENCETYPE_GET_INSTRUCTIONS_METHODDEF    \
+    {"get_instructions", (PyCFunction)InstructionSequenceType_get_instructions, METH_NOARGS, InstructionSequenceType_get_instructions__doc__},
+
+static PyObject *
+InstructionSequenceType_get_instructions_impl(_PyInstructionSequence *self);
+
+static PyObject *
+InstructionSequenceType_get_instructions(_PyInstructionSequence *self, PyObject *Py_UNUSED(ignored))
+{
+    return InstructionSequenceType_get_instructions_impl(self);
+}
+/*[clinic end generated code: output=8809d7aa11d9b2bb input=a9049054013a1b77]*/
diff --git a/Python/compile.c b/Python/compile.c
index 1e8f97e..3d856b7 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -32,6 +32,7 @@
 #include "pycore_code.h"          // _PyCode_New()
 #include "pycore_compile.h"
 #include "pycore_flowgraph.h"
+#include "pycore_instruction_sequence.h" // _PyInstructionSequence_New()
 #include "pycore_intrinsics.h"
 #include "pycore_long.h"          // _PyLong_GetZero()
 #include "pycore_pystate.h"       // _Py_GetConfig()
@@ -248,7 +249,7 @@ struct compiler_unit {
     PyObject *u_private;            /* for private name mangling */
     PyObject *u_static_attributes;  /* for class: attributes accessed via self.X */
 
-    instr_sequence u_instr_sequence; /* codegen output */
+    instr_sequence *u_instr_sequence; /* codegen output */
 
     int u_nfblocks;
     int u_in_inlined_comp;
@@ -281,12 +282,12 @@ struct compiler {
     int c_nestlevel;
     PyObject *c_const_cache;     /* Python dict holding all constants,
                                     including names tuple */
-    struct compiler_unit *u; /* compiler state for current block */
+    struct compiler_unit *u;     /* compiler state for current block */
     PyObject *c_stack;           /* Python list holding compiler_unit ptrs */
     PyArena *c_arena;            /* pointer to memory allocation arena */
 };
 
-#define INSTR_SEQUENCE(C) (&((C)->u->u_instr_sequence))
+#define INSTR_SEQUENCE(C) ((C)->u->u_instr_sequence)
 
 
 typedef struct {
@@ -567,7 +568,7 @@ dictbytype(PyObject *src, int scope_type, int flag, Py_ssize_t offset)
 static void
 compiler_unit_free(struct compiler_unit *u)
 {
-    PyInstructionSequence_Fini(&u->u_instr_sequence);
+    Py_CLEAR(u->u_instr_sequence);
     Py_CLEAR(u->u_ste);
     Py_CLEAR(u->u_metadata.u_name);
     Py_CLEAR(u->u_metadata.u_qualname);
@@ -976,7 +977,7 @@ compiler_addop_load_const(PyObject *const_cache, struct compiler_unit *u, locati
     if (arg < 0) {
         return ERROR;
     }
-    return codegen_addop_i(&u->u_instr_sequence, LOAD_CONST, arg, loc);
+    return codegen_addop_i(u->u_instr_sequence, LOAD_CONST, arg, loc);
 }
 
 static int
@@ -987,7 +988,7 @@ compiler_addop_o(struct compiler_unit *u, location loc,
     if (arg < 0) {
         return ERROR;
     }
-    return codegen_addop_i(&u->u_instr_sequence, opcode, arg, loc);
+    return codegen_addop_i(u->u_instr_sequence, opcode, arg, loc);
 }
 
 static int
@@ -1033,7 +1034,7 @@ compiler_addop_name(struct compiler_unit *u, location loc,
         arg <<= 2;
         arg |= 1;
     }
-    return codegen_addop_i(&u->u_instr_sequence, opcode, arg, loc);
+    return codegen_addop_i(u->u_instr_sequence, opcode, arg, loc);
 }
 
 /* Add an opcode with an integer argument */
@@ -1252,6 +1253,8 @@ compiler_enter_scope(struct compiler *c, identifier name,
         u->u_static_attributes = NULL;
     }
 
+    u->u_instr_sequence = (instr_sequence*)_PyInstructionSequence_New();
+
     /* Push the old compiler_unit on the stack. */
     if (c->u) {
         PyObject *capsule = PyCapsule_New(c->u, CAPSULE_NAME, NULL);
@@ -7526,7 +7529,7 @@ optimize_and_assemble_code_unit(struct compiler_unit *u, PyObject *const_cache,
     if (consts == NULL) {
         goto error;
     }
-    g = instr_sequence_to_cfg(&u->u_instr_sequence);
+    g = instr_sequence_to_cfg(u->u_instr_sequence);
     if (g == NULL) {
         goto error;
     }
@@ -7593,160 +7596,25 @@ optimize_and_assemble(struct compiler *c, int addNone)
  * a jump target label marking the beginning of a basic block.
  */
 
-static int
-instructions_to_instr_sequence(PyObject *instructions, instr_sequence *seq)
-{
-    assert(PyList_Check(instructions));
-
-    Py_ssize_t num_insts = PyList_GET_SIZE(instructions);
-    bool *is_target = PyMem_Calloc(num_insts, sizeof(bool));
-    if (is_target == NULL) {
-        return ERROR;
-    }
-    for (Py_ssize_t i = 0; i < num_insts; i++) {
-        PyObject *item = PyList_GET_ITEM(instructions, i);
-        if (!PyTuple_Check(item) || PyTuple_GET_SIZE(item) != 6) {
-            PyErr_SetString(PyExc_ValueError, "expected a 6-tuple");
-            goto error;
-        }
-        int opcode = PyLong_AsLong(PyTuple_GET_ITEM(item, 0));
-        if (PyErr_Occurred()) {
-            goto error;
-        }
-        if (HAS_TARGET(opcode)) {
-            int oparg = PyLong_AsLong(PyTuple_GET_ITEM(item, 1));
-            if (PyErr_Occurred()) {
-                goto error;
-            }
-            if (oparg < 0 || oparg >= num_insts) {
-                PyErr_SetString(PyExc_ValueError, "label out of range");
-                goto error;
-            }
-            is_target[oparg] = true;
-        }
-    }
-
-    for (int i = 0; i < num_insts; i++) {
-        if (is_target[i]) {
-            if (_PyInstructionSequence_UseLabel(seq, i) < 0) {
-                goto error;
-            }
-        }
-        PyObject *item = PyList_GET_ITEM(instructions, i);
-        if (!PyTuple_Check(item) || PyTuple_GET_SIZE(item) != 6) {
-            PyErr_SetString(PyExc_ValueError, "expected a 6-tuple");
-            goto error;
-        }
-        int opcode = PyLong_AsLong(PyTuple_GET_ITEM(item, 0));
-        if (PyErr_Occurred()) {
-            goto error;
-        }
-        int oparg;
-        if (OPCODE_HAS_ARG(opcode)) {
-            oparg = PyLong_AsLong(PyTuple_GET_ITEM(item, 1));
-            if (PyErr_Occurred()) {
-                goto error;
-            }
-        }
-        else {
-            oparg = 0;
-        }
-        location loc;
-        loc.lineno = PyLong_AsLong(PyTuple_GET_ITEM(item, 2));
-        if (PyErr_Occurred()) {
-            goto error;
-        }
-        loc.end_lineno = PyLong_AsLong(PyTuple_GET_ITEM(item, 3));
-        if (PyErr_Occurred()) {
-            goto error;
-        }
-        loc.col_offset = PyLong_AsLong(PyTuple_GET_ITEM(item, 4));
-        if (PyErr_Occurred()) {
-            goto error;
-        }
-        loc.end_col_offset = PyLong_AsLong(PyTuple_GET_ITEM(item, 5));
-        if (PyErr_Occurred()) {
-            goto error;
-        }
-        if (_PyInstructionSequence_Addop(seq, opcode, oparg, loc) < 0) {
-            goto error;
-        }
-    }
-    PyMem_Free(is_target);
-    return SUCCESS;
-error:
-    PyMem_Free(is_target);
-    return ERROR;
-}
-
-static cfg_builder*
-instructions_to_cfg(PyObject *instructions)
-{
-    cfg_builder *g = NULL;
-    instr_sequence seq;
-    memset(&seq, 0, sizeof(instr_sequence));
-
-    if (instructions_to_instr_sequence(instructions, &seq) < 0) {
-        goto error;
-    }
-    g = instr_sequence_to_cfg(&seq);
-    if (g == NULL) {
-        goto error;
-    }
-    PyInstructionSequence_Fini(&seq);
-    return g;
-error:
-    _PyCfgBuilder_Free(g);
-    PyInstructionSequence_Fini(&seq);
-    return NULL;
-}
 
 static PyObject *
-instr_sequence_to_instructions(instr_sequence *seq)
+cfg_to_instruction_sequence(cfg_builder *g)
 {
-    PyObject *instructions = PyList_New(0);
-    if (instructions == NULL) {
-        return NULL;
-    }
-    for (int i = 0; i < seq->s_used; i++) {
-        instruction *instr = &seq->s_instrs[i];
-        location loc = instr->i_loc;
-        PyObject *inst_tuple = Py_BuildValue(
-            "(iiiiii)", instr->i_opcode, instr->i_oparg,
-            loc.lineno, loc.end_lineno,
-            loc.col_offset, loc.end_col_offset);
-        if (inst_tuple == NULL) {
+    instr_sequence *seq = (instr_sequence *)_PyInstructionSequence_New();
+    if (seq != NULL) {
+        if (_PyCfg_ToInstructionSequence(g, seq) < 0) {
             goto error;
         }
-
-        int res = PyList_Append(instructions, inst_tuple);
-        Py_DECREF(inst_tuple);
-        if (res != 0) {
+        if (_PyInstructionSequence_ApplyLabelMap(seq) < 0) {
             goto error;
         }
     }
-    return instructions;
+    return (PyObject*)seq;
 error:
-    Py_XDECREF(instructions);
+    PyInstructionSequence_Fini(seq);
     return NULL;
 }
 
-static PyObject *
-cfg_to_instructions(cfg_builder *g)
-{
-    instr_sequence seq;
-    memset(&seq, 0, sizeof(seq));
-    if (_PyCfg_ToInstructionSequence(g, &seq) < 0) {
-        return NULL;
-    }
-    if (_PyInstructionSequence_ApplyLabelMap(&seq) < 0) {
-        return NULL;
-    }
-    PyObject *res = instr_sequence_to_instructions(&seq);
-    PyInstructionSequence_Fini(&seq);
-    return res;
-}
-
 // C implementation of inspect.cleandoc()
 //
 // Difference from inspect.cleandoc():
@@ -7916,13 +7784,8 @@ _PyCompile_CodeGen(PyObject *ast, PyObject *filename, PyCompilerFlags *pflags,
     if (_PyInstructionSequence_ApplyLabelMap(INSTR_SEQUENCE(c)) < 0) {
         return NULL;
     }
-
-    PyObject *insts = instr_sequence_to_instructions(INSTR_SEQUENCE(c));
-    if (insts == NULL) {
-        goto finally;
-    }
-    res = PyTuple_Pack(2, insts, metadata);
-    Py_DECREF(insts);
+    /* Allocate a copy of the instruction sequence on the heap */
+    res = PyTuple_Pack(2, INSTR_SEQUENCE(c), metadata);
 
 finally:
     Py_XDECREF(metadata);
@@ -7933,16 +7796,19 @@ finally:
 }
 
 PyObject *
-_PyCompile_OptimizeCfg(PyObject *instructions, PyObject *consts, int nlocals)
+_PyCompile_OptimizeCfg(PyObject *seq, PyObject *consts, int nlocals)
 {
-    cfg_builder *g = NULL;
-    PyObject *res = NULL;
+    if (!_PyInstructionSequence_Check(seq)) {
+        PyErr_SetString(PyExc_ValueError, "expected an instruction sequence");
+        return NULL;
+    }
     PyObject *const_cache = PyDict_New();
     if (const_cache == NULL) {
         return NULL;
     }
 
-    g = instructions_to_cfg(instructions);
+    PyObject *res = NULL;
+    cfg_builder *g = instr_sequence_to_cfg((instr_sequence*)seq);
     if (g == NULL) {
         goto error;
     }
@@ -7951,7 +7817,7 @@ _PyCompile_OptimizeCfg(PyObject *instructions, PyObject *consts, int nlocals)
                                 nparams, firstlineno) < 0) {
         goto error;
     }
-    res = cfg_to_instructions(g);
+    res = cfg_to_instruction_sequence(g);
 error:
     Py_DECREF(const_cache);
     _PyCfgBuilder_Free(g);
@@ -7962,8 +7828,12 @@ int _PyCfg_JumpLabelsToTargets(cfg_builder *g);
 
 PyCodeObject *
 _PyCompile_Assemble(_PyCompile_CodeUnitMetadata *umd, PyObject *filename,
-                    PyObject *instructions)
+                    PyObject *seq)
 {
+    if (!_PyInstructionSequence_Check(seq)) {
+        PyErr_SetString(PyExc_TypeError, "expected an instruction sequence");
+        return NULL;
+    }
     cfg_builder *g = NULL;
     PyCodeObject *co = NULL;
     instr_sequence optimized_instrs;
@@ -7974,7 +7844,7 @@ _PyCompile_Assemble(_PyCompile_CodeUnitMetadata *umd, PyObject *filename,
         return NULL;
     }
 
-    g = instructions_to_cfg(instructions);
+    g = instr_sequence_to_cfg((instr_sequence*)seq);
     if (g == NULL) {
         goto error;
     }
diff --git a/Python/instruction_sequence.c b/Python/instruction_sequence.c
index 597d2b7..d843d5f 100644
--- a/Python/instruction_sequence.c
+++ b/Python/instruction_sequence.c
@@ -141,6 +141,21 @@ _PyInstructionSequence_InsertInstruction(instr_sequence *seq, int pos,
     return SUCCESS;
 }
 
+int
+_PyInstructionSequence_AddNested(instr_sequence *seq, instr_sequence *nested)
+{
+    if (seq->s_nested == NULL) {
+        seq->s_nested = PyList_New(0);
+        if (seq->s_nested == NULL) {
+            return ERROR;
+        }
+    }
+    if (PyList_Append(seq->s_nested, (PyObject*)nested) < 0) {
+        return ERROR;
+    }
+    return SUCCESS;
+}
+
 void
 PyInstructionSequence_Fini(instr_sequence *seq) {
     PyMem_Free(seq->s_labelmap);
@@ -149,3 +164,288 @@ PyInstructionSequence_Fini(instr_sequence *seq) {
     PyMem_Free(seq->s_instrs);
     seq->s_instrs = NULL;
 }
+
+/*[clinic input]
+class InstructionSequenceType "_PyInstructionSequence *" "&_PyInstructionSequence_Type"
+[clinic start generated code]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=589963e07480390f]*/
+
+#include "clinic/instruction_sequence.c.h"
+
+static _PyInstructionSequence*
+inst_seq_create(void)
+{
+    _PyInstructionSequence *seq;
+    seq = PyObject_GC_New(_PyInstructionSequence, &_PyInstructionSequence_Type);
+    if (seq == NULL) {
+        return NULL;
+    }
+    seq->s_instrs = NULL;
+    seq->s_allocated = 0;
+    seq->s_used = 0;
+    seq->s_next_free_label = 0;
+    seq->s_labelmap = NULL;
+    seq->s_labelmap_size = 0;
+    seq->s_nested = NULL;
+
+    PyObject_GC_Track(seq);
+    return seq;
+}
+
+PyObject*
+_PyInstructionSequence_New(void)
+{
+    _PyInstructionSequence *seq = inst_seq_create();
+    if (seq == NULL) {
+        return NULL;
+    }
+    return (PyObject*)seq;
+}
+
+/*[clinic input]
+@classmethod
+InstructionSequenceType.__new__ as inst_seq_new
+
+Create a new InstructionSequence object.
+[clinic start generated code]*/
+
+static PyObject *
+inst_seq_new_impl(PyTypeObject *type)
+/*[clinic end generated code: output=98881de92c8876f6 input=b393150146849c74]*/
+{
+    return (PyObject*)inst_seq_create();
+}
+
+/*[clinic input]
+InstructionSequenceType.use_label
+
+  label: int
+
+Place label at current location.
+[clinic start generated code]*/
+
+static PyObject *
+InstructionSequenceType_use_label_impl(_PyInstructionSequence *self,
+                                       int label)
+/*[clinic end generated code: output=4c06bbacb2854755 input=da55f49bb91841f3]*/
+
+{
+    if (_PyInstructionSequence_UseLabel(self, label) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+/*[clinic input]
+InstructionSequenceType.addop
+
+  opcode: int
+  oparg: int
+  lineno: int
+  col_offset: int
+  end_lineno: int
+  end_col_offset: int
+
+Append an instruction.
+[clinic start generated code]*/
+
+static PyObject *
+InstructionSequenceType_addop_impl(_PyInstructionSequence *self, int opcode,
+                                   int oparg, int lineno, int col_offset,
+                                   int end_lineno, int end_col_offset)
+/*[clinic end generated code: output=af0cc22c048dfbf3 input=012762ac88198713]*/
+{
+    _Py_SourceLocation loc = {lineno, col_offset, end_lineno, end_col_offset};
+    if (_PyInstructionSequence_Addop(self, opcode, oparg, loc) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+/*[clinic input]
+InstructionSequenceType.new_label -> int
+
+Return a new label.
+[clinic start generated code]*/
+
+static int
+InstructionSequenceType_new_label_impl(_PyInstructionSequence *self)
+/*[clinic end generated code: output=dcb0589e4f5bf4bd input=c66040b9897bc327]*/
+{
+    _PyJumpTargetLabel lbl = _PyInstructionSequence_NewLabel(self);
+    return lbl.id;
+}
+
+/*[clinic input]
+InstructionSequenceType.add_nested
+
+  nested: object
+
+Add a nested sequence.
+[clinic start generated code]*/
+
+static PyObject *
+InstructionSequenceType_add_nested_impl(_PyInstructionSequence *self,
+                                        PyObject *nested)
+/*[clinic end generated code: output=14540fad459f7971 input=f2c482568b3b3c0f]*/
+{
+    if (!_PyInstructionSequence_Check(nested)) {
+        PyErr_Format(PyExc_TypeError,
+                     "expected an instruction sequence, not %T",
+                     Py_TYPE(nested));
+        return NULL;
+    }
+    if (_PyInstructionSequence_AddNested(self, (_PyInstructionSequence*)nested) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+/*[clinic input]
+InstructionSequenceType.get_nested
+
+Add a nested sequence.
+[clinic start generated code]*/
+
+static PyObject *
+InstructionSequenceType_get_nested_impl(_PyInstructionSequence *self)
+/*[clinic end generated code: output=f415112c292630cb input=e429e474c57b95b4]*/
+{
+    if (self->s_nested == NULL) {
+        return PyList_New(0);
+    }
+    return Py_NewRef(self->s_nested);
+}
+
+/*[clinic input]
+InstructionSequenceType.get_instructions
+
+Return the instructions as a list of tuples or labels.
+[clinic start generated code]*/
+
+static PyObject *
+InstructionSequenceType_get_instructions_impl(_PyInstructionSequence *self)
+/*[clinic end generated code: output=23f4f3f894c301b3 input=fbadb5dadb611291]*/
+{
+    if (_PyInstructionSequence_ApplyLabelMap(self) < 0) {
+        return NULL;
+    }
+    PyObject *instructions = PyList_New(0);
+    if (instructions == NULL) {
+        return NULL;
+    }
+    for (int i = 0; i < self->s_used; i++) {
+        instruction *instr = &self->s_instrs[i];
+        location loc = instr->i_loc;
+        PyObject *inst_tuple;
+
+        if (OPCODE_HAS_ARG(instr->i_opcode)) {
+            inst_tuple = Py_BuildValue(
+                "(iiiiii)", instr->i_opcode, instr->i_oparg,
+                loc.lineno, loc.end_lineno,
+                loc.col_offset, loc.end_col_offset);
+        }
+        else {
+            inst_tuple = Py_BuildValue(
+                "(iOiiii)", instr->i_opcode, Py_None,
+                loc.lineno, loc.end_lineno,
+                loc.col_offset, loc.end_col_offset);
+        }
+        if (inst_tuple == NULL) {
+            goto error;
+        }
+
+        int res = PyList_Append(instructions, inst_tuple);
+        Py_DECREF(inst_tuple);
+        if (res != 0) {
+            goto error;
+        }
+    }
+    return instructions;
+error:
+    Py_XDECREF(instructions);
+    return NULL;
+}
+
+static PyMethodDef inst_seq_methods[] = {
+   INSTRUCTIONSEQUENCETYPE_ADDOP_METHODDEF
+   INSTRUCTIONSEQUENCETYPE_NEW_LABEL_METHODDEF
+   INSTRUCTIONSEQUENCETYPE_USE_LABEL_METHODDEF
+   INSTRUCTIONSEQUENCETYPE_ADD_NESTED_METHODDEF
+   INSTRUCTIONSEQUENCETYPE_GET_NESTED_METHODDEF
+   INSTRUCTIONSEQUENCETYPE_GET_INSTRUCTIONS_METHODDEF
+   {NULL, NULL, 0, NULL},
+};
+
+static PyMemberDef inst_seq_memberlist[] = {
+    {NULL}      /* Sentinel */
+};
+
+static PyGetSetDef inst_seq_getsetters[] = {
+    {NULL}      /* Sentinel */
+};
+
+static void
+inst_seq_dealloc(_PyInstructionSequence *seq)
+{
+    PyObject_GC_UnTrack(seq);
+    Py_TRASHCAN_BEGIN(seq, inst_seq_dealloc)
+    PyInstructionSequence_Fini(seq);
+    PyObject_GC_Del(seq);
+    Py_TRASHCAN_END
+}
+
+static int
+inst_seq_traverse(_PyInstructionSequence *seq, visitproc visit, void *arg)
+{
+    Py_VISIT(seq->s_nested);
+    return 0;
+}
+
+static int
+inst_seq_clear(_PyInstructionSequence *seq)
+{
+    Py_CLEAR(seq->s_nested);
+    return 0;
+}
+
+PyTypeObject _PyInstructionSequence_Type = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "InstructionSequence",
+    sizeof(_PyInstructionSequence),
+    0,
+    (destructor)inst_seq_dealloc, /*tp_dealloc*/
+    0,                  /*tp_vectorcall_offset*/
+    0,                  /*tp_getattr*/
+    0,                  /*tp_setattr*/
+    0,                  /*tp_as_async*/
+    0,                  /*tp_repr*/
+    0,                  /*tp_as_number*/
+    0,                  /*tp_as_sequence*/
+    0,                  /*tp_as_mapping*/
+    0,                  /* tp_hash */
+    0,                  /* tp_call */
+    0,                  /* tp_str */
+    PyObject_GenericGetAttr,  /* tp_getattro */
+    0,                  /* tp_setattro */
+    0,                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
+    inst_seq_new__doc__,                    /* tp_doc */
+    (traverseproc)inst_seq_traverse,        /* tp_traverse */
+    (inquiry)inst_seq_clear,                /* tp_clear */
+    0,                                      /* tp_richcompare */
+    0,                                      /* tp_weaklistoffset */
+    0,                                      /* tp_iter */
+    0,                                      /* tp_iternext */
+    inst_seq_methods,                       /* tp_methods */
+    inst_seq_memberlist,                    /* tp_members */
+    inst_seq_getsetters,                    /* tp_getset */
+    0,                                      /* tp_base */
+    0,                                      /* tp_dict */
+    0,                                      /* tp_descr_get */
+    0,                                      /* tp_descr_set */
+    0,                                      /* tp_dictoffset */
+    0,                                      /* tp_init */
+    0,                                      /* tp_alloc */
+    inst_seq_new,                           /* tp_new */
+};
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 65f94e5..79a8f85 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -103,6 +103,7 @@ Python/bltinmodule.c	-	PyZip_Type	-
 Python/context.c	-	PyContextToken_Type	-
 Python/context.c	-	PyContextVar_Type	-
 Python/context.c	-	PyContext_Type	-
+Python/instruction_sequence.c	-	_PyInstructionSequence_Type	-
 Python/traceback.c	-	PyTraceBack_Type	-
 
 ##-----------------------