GH-125837: Split `LOAD_CONST` into three. (GH-125972)

* Add LOAD_CONST_IMMORTAL opcode

* Add LOAD_SMALL_INT opcode

* Remove RETURN_CONST opcode

1 files changed, 18 insertions, 20 deletions

diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index 6f838da6018..958170f675e 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -775,7 +775,6 @@ class TestSpecifics(unittest.TestCase):
             self.assertEqual(repr(f1()), repr(const))
 
         check_same_constant(None)
-        check_same_constant(0)
         check_same_constant(0.0)
         check_same_constant(b'abc')
         check_same_constant('abc')
@@ -853,9 +852,9 @@ class TestSpecifics(unittest.TestCase):
         eval(compile(code, "file.py", "exec"), g)
         exec(code, g)
         f = g['f']
-        expected = tuple([None, '', 1] + [f't{i}' for i in range(N)])
+        expected = tuple([None, ''] + [f't{i}' for i in range(N)])
         self.assertEqual(f.__code__.co_consts, expected)
-        expected = "".join(expected[3:])
+        expected = "".join(expected[2:])
         self.assertEqual(expected, f())
 
     # Stripping unused constants is not a strict requirement for the
@@ -867,7 +866,7 @@ class TestSpecifics(unittest.TestCase):
         def f1():
             "docstring"
             return 42
-        self.assertEqual(f1.__code__.co_consts, (f1.__doc__, 42))
+        self.assertEqual(f1.__code__.co_consts, (f1.__doc__,))
 
     # This is a regression test for a CPython specific peephole optimizer
     # implementation bug present in a few releases.  It's assertion verifies
@@ -884,7 +883,7 @@ class TestSpecifics(unittest.TestCase):
         # RETURN_VALUE opcode.  This does not always crash an interpreter.
         # When you build with the clang memory sanitizer it reliably aborts.
         self.assertEqual(
-            'RETURN_CONST',
+            'RETURN_VALUE',
             list(dis.get_instructions(unused_code_at_end))[-1].opname)
 
     @support.cpython_only
@@ -982,7 +981,6 @@ class TestSpecifics(unittest.TestCase):
             self.assertEqual(repr(f1()), repr(const1))
             self.assertEqual(repr(f2()), repr(const2))
 
-        check_different_constants(0, 0.0)
         check_different_constants(+0.0, -0.0)
         check_different_constants((0,), (0.0,))
         check_different_constants('a', b'a')
@@ -1045,8 +1043,8 @@ class TestSpecifics(unittest.TestCase):
 
         for func in funcs:
             opcodes = list(dis.get_instructions(func))
-            self.assertLessEqual(len(opcodes), 3)
-            self.assertEqual('RETURN_CONST', opcodes[-1].opname)
+            self.assertLessEqual(len(opcodes), 4)
+            self.assertEqual('RETURN_VALUE', opcodes[-1].opname)
             self.assertEqual(None, opcodes[-1].argval)
 
     def test_false_while_loop(self):
@@ -1063,8 +1061,8 @@ class TestSpecifics(unittest.TestCase):
         # Check that we did not raise but we also don't generate bytecode
         for func in funcs:
             opcodes = list(dis.get_instructions(func))
-            self.assertEqual(2, len(opcodes))
-            self.assertEqual('RETURN_CONST', opcodes[1].opname)
+            self.assertEqual(3, len(opcodes))
+            self.assertEqual('RETURN_VALUE', opcodes[-1].opname)
             self.assertEqual(None, opcodes[1].argval)
 
     def test_consts_in_conditionals(self):
@@ -1738,7 +1736,7 @@ class TestSourcePositions(unittest.TestCase):
             line=1, end_line=3, column=0, end_column=36, occurrence=1)
         #  The "error msg":
         self.assertOpcodeSourcePositionIs(compiled_code, 'LOAD_CONST',
-            line=3, end_line=3, column=25, end_column=36, occurrence=4)
+            line=3, end_line=3, column=25, end_column=36, occurrence=2)
         self.assertOpcodeSourcePositionIs(compiled_code, 'CALL',
             line=1, end_line=3, column=0, end_column=36, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'RAISE_VARARGS',
@@ -1760,7 +1758,7 @@ class TestSourcePositions(unittest.TestCase):
             line=1, end_line=2, column=1, end_column=8, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=1, end_line=2, column=1, end_column=8, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
             line=4, end_line=4, column=7, end_column=14, occurrence=1)
 
     def test_multiline_async_generator_expression(self):
@@ -1777,7 +1775,7 @@ class TestSourcePositions(unittest.TestCase):
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'YIELD_VALUE',
             line=1, end_line=2, column=1, end_column=8, occurrence=2)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
             line=1, end_line=6, column=0, end_column=32, occurrence=1)
 
     def test_multiline_list_comprehension(self):
@@ -1815,7 +1813,7 @@ class TestSourcePositions(unittest.TestCase):
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
             line=2, end_line=7, column=4, end_column=36, occurrence=1)
 
     def test_multiline_set_comprehension(self):
@@ -1853,7 +1851,7 @@ class TestSourcePositions(unittest.TestCase):
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
             line=2, end_line=7, column=4, end_column=36, occurrence=1)
 
     def test_multiline_dict_comprehension(self):
@@ -1891,7 +1889,7 @@ class TestSourcePositions(unittest.TestCase):
             line=2, end_line=3, column=5, end_column=11, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=2, end_line=3, column=5, end_column=11, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
             line=2, end_line=7, column=4, end_column=36, occurrence=1)
 
     def test_matchcase_sequence(self):
@@ -2204,8 +2202,8 @@ class TestSourcePositions(unittest.TestCase):
             start_line, end_line, _, _ = instr.positions
             self.assertEqual(start_line, end_line)
 
-        # Expect three load None instructions for the no-exception __exit__ call,
-        # and one RETURN_VALUE.
+        # Expect four `LOAD_CONST None` instructions:
+        # three for the no-exception __exit__ call, and one for the return.
         # They should all have the locations of the context manager ('xyz').
 
         load_none = [instr for instr in dis.get_instructions(f) if
@@ -2213,8 +2211,8 @@ class TestSourcePositions(unittest.TestCase):
         return_value = [instr for instr in dis.get_instructions(f) if
                         instr.opname == 'RETURN_VALUE']
 
-        self.assertEqual(len(load_none), 3)
-        self.assertEqual(len(return_value), 1)
+        self.assertEqual(len(load_none), 4)
+        self.assertEqual(len(return_value), 2)
         for instr in load_none + return_value:
             start_line, end_line, start_col, end_col = instr.positions
             self.assertEqual(start_line, f.__code__.co_firstlineno + 1)