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bytecode_assembler.py — CPython 3.12 bytecode assembler for the Sovereign engine.
Operates at the raw opcode level, producing types.CodeType objects and raw bytecode
bytes. Supports label-based forward/backward jumps, constant pooling, and disassembly.
Part of the SOVEREIGN_IR PYTHON_C_BRIDGE_IR pipeline.
Agent A (Cognition) — HyperKittyConstraintDSL v1.0
"""
from __future__ import annotations
import dis
import io
import math
import struct
import types
from dataclasses import dataclass, field
from enum import IntEnum
from typing import Any, Optional
# ---------------------------------------------------------------------------
# Opcode definitions — CPython 3.12 values drawn from dis.opmap
# ---------------------------------------------------------------------------
class Opcode(IntEnum):
"""CPython 3.12 opcode enumeration with correct integer values."""
# Misc / no-arg
NOP = 9
RESUME = 149
CACHE = 0
# Stack manipulation
POP_TOP = 1
COPY = 120
SWAP = 99
# Unary ops
UNARY_NEGATIVE = 11
UNARY_NOT = 12
UNARY_INVERT = 15
GET_ITER = 68
GET_YIELD_FROM_ITER = 69
# Binary / in-place ops
BINARY_SUBSCR = 25
STORE_SUBSCR = 60
DELETE_SUBSCR = 61
BINARY_OP = 122
# Comparisons
COMPARE_OP = 107
IS_OP = 117
CONTAINS_OP = 118
# Attributes
LOAD_ATTR = 106
STORE_ATTR = 95
DELETE_ATTR = 96
LOAD_SUPER_ATTR = 141
# Names / globals / builtins
LOAD_NAME = 101
STORE_NAME = 90
DELETE_NAME = 91
LOAD_GLOBAL = 116
STORE_GLOBAL = 97
DELETE_GLOBAL = 98
LOAD_DEREF = 137
STORE_DEREF = 125
DELETE_DEREF = 138
COPY_FREE_VARS = 149 # alias
# Fast locals
LOAD_FAST = 124
LOAD_FAST_CHECK = 127
LOAD_FAST_AND_CLEAR = 126
STORE_FAST = 125
DELETE_FAST = 126
# Constants
LOAD_CONST = 100
# Collections
BUILD_TUPLE = 102
BUILD_LIST = 103
BUILD_SET = 104
BUILD_MAP = 105
BUILD_CONST_KEY_MAP = 156
BUILD_SLICE = 133
BUILD_STRING = 157
LIST_APPEND = 45
SET_ADD = 146
MAP_ADD = 147
LIST_EXTEND = 162
SET_UPDATE = 163
DICT_MERGE = 164
DICT_UPDATE = 165
BUILD_DICT = 105 # alias
# Unpacking
UNPACK_SEQUENCE = 92
UNPACK_EX = 94
# Jumps
JUMP_FORWARD = 110
JUMP_BACKWARD = 140
JUMP_BACKWARD_NO_INTERRUPT = 134
POP_JUMP_IF_TRUE = 115
POP_JUMP_IF_FALSE = 114
POP_JUMP_IF_NONE = 128
POP_JUMP_IF_NOT_NONE = 129
JUMP_IF_TRUE_OR_POP = 112
JUMP_IF_FALSE_OR_POP = 111
# Calls
CALL = 171
CALL_FUNCTION_EX = 142
PUSH_NULL = 2
PRECALL = 166
KW_NAMES = 172
# Functions / closures
MAKE_FUNCTION = 132
RETURN_VALUE = 83
RETURN_CONST = 121
YIELD_VALUE = 86
YIELD_FROM = 72
SEND = 123
# Exceptions
RAISE_VARARGS = 130
POP_EXCEPT = 89
PUSH_EXC_INFO = 35
CHECK_EXC_MATCH = 36
WITH_EXCEPT_START = 49
BEFORE_WITH = 53
# Imports
IMPORT_NAME = 108
IMPORT_FROM = 109
IMPORT_STAR = 84
# Generators / coroutines
GET_AWAITABLE = 73
GET_AITER = 75
GET_ANEXT = 76
END_ASYNC_FOR = 54
BEFORE_ASYNC_WITH = 52
ASYNC_GEN_WRAP = 55
# Format / match
FORMAT_VALUE = 155
MATCH_MAPPING = 27
MATCH_SEQUENCE = 28
MATCH_KEYS = 29
MATCH_CLASS = 152
COPY_DICT_WITHOUT_KEYS = 34
GET_LEN = 30
# Misc
PRINT_EXPR = 70
SETUP_ANNOTATIONS = 85
LOAD_BUILD_CLASS = 71
LOAD_CLASSDEREF = 148
FOR_ITER = 68 # alias — same as GET_ITER in enum
END_FOR = 4
@classmethod
def from_name(cls, name: str) -> 'Opcode':
"""Look up opcode by name, falling back to dis.opmap."""
try:
return cls[name]
except KeyError:
val = dis.opmap.get(name)
if val is None:
raise KeyError(f"Unknown opcode: {name}")
return cls(val)
def has_arg(self) -> bool:
"""Return True if this opcode takes an argument (value >= dis.HAVE_ARGUMENT)."""
return int(self) >= dis.HAVE_ARGUMENT
# ---------------------------------------------------------------------------
# Data structures
# ---------------------------------------------------------------------------
@dataclass
class Instruction:
"""A single bytecode instruction with optional label and line info."""
opcode: Opcode
arg: int = 0
label: Optional[str] = None # label this instruction is the target of
lineno: int = 0
# resolved absolute target offset (for jumps)
_resolved_target: int = field(default=-1, repr=False, compare=False)
def __post_init__(self):
if isinstance(self.opcode, int):
self.opcode = Opcode(self.opcode)
def is_jump(self) -> bool:
return self.opcode in _JUMP_OPCODES
def encoded_size(self) -> int:
"""Return the number of bytes this instruction takes (2 or more)."""
if self.arg <= 0xFF:
return 2
elif self.arg <= 0xFFFF:
return 4
elif self.arg <= 0xFFFFFF:
return 6
else:
return 8
def encode(self) -> bytes:
"""Encode to bytes using EXTENDED_ARG for large arguments."""
out = bytearray()
arg = self.arg
if arg > 0xFFFFFF:
out.append(144) # EXTENDED_ARG
out.append((arg >> 24) & 0xFF)
if arg > 0xFFFF:
out.append(144)
out.append((arg >> 16) & 0xFF)
if arg > 0xFF:
out.append(144)
out.append((arg >> 8) & 0xFF)
out.append(int(self.opcode))
out.append(arg & 0xFF)
return bytes(out)
@dataclass
class Label:
"""Named label marking a position in the bytecode stream."""
name: str
position: int = -1 # byte offset, filled in after assembly
def is_resolved(self) -> bool:
return self.position >= 0
# Jump opcodes that need target resolution
_JUMP_OPCODES = frozenset({
Opcode.JUMP_FORWARD,
Opcode.JUMP_BACKWARD,
Opcode.JUMP_BACKWARD_NO_INTERRUPT,
Opcode.POP_JUMP_IF_TRUE,
Opcode.POP_JUMP_IF_FALSE,
Opcode.POP_JUMP_IF_NONE,
Opcode.POP_JUMP_IF_NOT_NONE,
Opcode.JUMP_IF_TRUE_OR_POP,
Opcode.JUMP_IF_FALSE_OR_POP,
Opcode.FOR_ITER,
})
# ---------------------------------------------------------------------------
# InstructionBuffer
# ---------------------------------------------------------------------------
class InstructionBuffer:
"""Mutable sequence of Instructions with label resolution."""
def __init__(self):
self._instructions: list[Instruction] = []
self._labels: dict[str, Label] = {} # name -> Label
self._pending_jumps: list[tuple[int, str]] = [] # (instr_index, label_name)
def append(self, instr: Instruction) -> None:
self._instructions.append(instr)
def add_label(self, name: str) -> Label:
lbl = Label(name)
self._labels[name] = lbl
# Mark the next instruction's position once we know it
return lbl
def mark_label_here(self, name: str) -> None:
"""Associate label with the current (next) instruction index."""
offset = self._compute_offset(len(self._instructions))
lbl = self._labels.setdefault(name, Label(name))
lbl.position = offset
# If any prior instruction referred to this label, patch it
if self._instructions and self._instructions[-1].label == name:
pass # already set
def _compute_offset(self, up_to_index: int) -> int:
total = 0
for i, instr in enumerate(self._instructions):
if i >= up_to_index:
break
total += instr.encoded_size()
return total
def resolve_labels(self) -> None:
"""
Two-pass resolution:
Pass 1: compute byte offsets for all labels.
Pass 2: patch jump instruction args.
"""
# Pass 1: build offset table
offset = 0
for instr in self._instructions:
if instr.label is not None:
lbl = self._labels.get(instr.label)
if lbl is not None and lbl.position < 0:
lbl.position = offset
offset += instr.encoded_size()
# Pass 2: patch jumps
offset = 0
for instr in self._instructions:
if instr.is_jump() and isinstance(instr.arg, str):
label_name = instr.arg # type: ignore[assignment]
lbl = self._labels.get(label_name)
if lbl is None or not lbl.is_resolved():
raise AssemblerError(f"Unresolved label: {label_name}")
after_instr = offset + instr.encoded_size()
if instr.opcode == Opcode.JUMP_FORWARD:
instr.arg = (lbl.position - after_instr) // 2
elif instr.opcode == Opcode.JUMP_BACKWARD:
instr.arg = (after_instr - lbl.position) // 2
else:
# absolute for conditional jumps in 3.12 (offset/2)
instr.arg = lbl.position // 2
offset += instr.encoded_size()
def to_bytes(self) -> bytes:
self.resolve_labels()
out = bytearray()
for instr in self._instructions:
out.extend(instr.encode())
return bytes(out)
def size(self) -> int:
return sum(i.encoded_size() for i in self._instructions)
def __len__(self) -> int:
return len(self._instructions)
def __iter__(self):
return iter(self._instructions)
# ---------------------------------------------------------------------------
# Assembler error
# ---------------------------------------------------------------------------
class AssemblerError(Exception):
pass
# ---------------------------------------------------------------------------
# BytecodeAssembler — main class
# ---------------------------------------------------------------------------
class BytecodeAssembler:
"""
High-level Python bytecode assembler.
Builds a sequence of CPython instructions, manages constant/name pools,
and can produce a raw bytecode bytes object or a full types.CodeType.
"""
def __init__(self, name: str = "<assembled>", filename: str = "<string>"):
self.name = name
self.filename = filename
self._buf = InstructionBuffer()
self._consts: list[Any] = []
self._varnames: list[str] = []
self._names: list[str] = [] # globals / attributes
self._freevars: list[str] = []
self._cellvars: list[str] = []
self._lineno_table: list[tuple[int, int]] = [] # (offset, lineno)
self._current_lineno = 1
self._label_counter = 0
self._stack_depth = 0
self._max_stack = 0
# --- internal helpers ---------------------------------------------------
def _push(self, n: int = 1) -> None:
self._stack_depth += n
if self._stack_depth > self._max_stack:
self._max_stack = self._stack_depth
def _pop(self, n: int = 1) -> None:
self._stack_depth -= n
if self._stack_depth < 0:
raise AssemblerError("Stack underflow")
def _const_index(self, value: Any) -> int:
for i, c in enumerate(self._consts):
if type(c) is type(value) and c == value:
return i
self._consts.append(value)
return len(self._consts) - 1
def _varname_index(self, name: str) -> int:
if name not in self._varnames:
self._varnames.append(name)
return self._varnames.index(name)
def _name_index(self, name: str) -> int:
if name not in self._names:
self._names.append(name)
return self._names.index(name)
def _emit_raw(self, opcode: Opcode, arg: int = 0) -> Instruction:
instr = Instruction(opcode=opcode, arg=arg, lineno=self._current_lineno)
self._buf.append(instr)
return instr
# --- public emit interface ----------------------------------------------
def emit(self, opcode: Opcode, arg: int = 0) -> None:
"""Emit a raw opcode with integer argument."""
self._emit_raw(opcode, arg)
def set_lineno(self, n: int) -> None:
self._current_lineno = n
def new_label(self) -> str:
self._label_counter += 1
return f"_L{self._label_counter}"
def emit_label(self, name: str) -> Label:
"""
Mark the current position as the target of label `name`.
Returns the Label object (position set after assemble()).
"""
self._buf.mark_label_here(name)
lbl = self._buf._labels.get(name, Label(name))
self._buf._labels[name] = lbl
return lbl
# --- high-level emitters ------------------------------------------------
def load_const(self, value: Any) -> None:
idx = self._const_index(value)
self._emit_raw(Opcode.LOAD_CONST, idx)
self._push()
def load_fast(self, name: str) -> None:
idx = self._varname_index(name)
self._emit_raw(Opcode.LOAD_FAST, idx)
self._push()
def store_fast(self, name: str) -> None:
idx = self._varname_index(name)
self._emit_raw(Opcode.STORE_FAST, idx)
self._pop()
def load_global(self, name: str, push_null: bool = False) -> None:
idx = self._name_index(name)
# In 3.12, LOAD_GLOBAL arg = (namei << 1) | push_null_flag
arg = (idx << 1) | (1 if push_null else 0)
self._emit_raw(Opcode.LOAD_GLOBAL, arg)
self._push(2 if push_null else 1)
def store_global(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.STORE_GLOBAL, idx)
self._pop()
def load_attr(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.LOAD_ATTR, idx)
def store_attr(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.STORE_ATTR, idx)
self._pop(2)
def call(self, argc: int) -> None:
self._emit_raw(Opcode.CALL, argc)
self._pop(argc + 1)
self._push()
def push_null(self) -> None:
self._emit_raw(Opcode.PUSH_NULL)
self._push()
def return_value(self) -> None:
self._emit_raw(Opcode.RETURN_VALUE)
self._pop()
def return_const(self, value: Any) -> None:
idx = self._const_index(value)
self._emit_raw(Opcode.RETURN_CONST, idx)
def pop_top(self) -> None:
self._emit_raw(Opcode.POP_TOP)
self._pop()
def dup_top(self) -> None:
self._emit_raw(Opcode.COPY, 1)
self._push()
def swap(self, i: int = 2) -> None:
self._emit_raw(Opcode.SWAP, i)
def binary_op(self, op: int) -> None:
"""op: 0=+, 1=&, 2=//, 3@, 4=lshift, 5=%, 6=*, 7=**, 8=rshift, 9=-, 10=/, 11=|, 12=^"""
self._emit_raw(Opcode.BINARY_OP, op)
self._pop()
def compare_op(self, op: int) -> None:
"""op: 0=<, 1=<=, 2===, 3=!=, 4=>, 5>="""
self._emit_raw(Opcode.COMPARE_OP, op)
self._pop()
def jump_forward(self, label: str) -> None:
instr = self._emit_raw(Opcode.JUMP_FORWARD, 0)
instr.arg = label # type: ignore[assignment]
def jump_backward(self, label: str) -> None:
instr = self._emit_raw(Opcode.JUMP_BACKWARD, 0)
instr.arg = label # type: ignore[assignment]
def pop_jump_if_false(self, label: str) -> None:
instr = self._emit_raw(Opcode.POP_JUMP_IF_FALSE, 0)
instr.arg = label # type: ignore[assignment]
self._pop()
def pop_jump_if_true(self, label: str) -> None:
instr = self._emit_raw(Opcode.POP_JUMP_IF_TRUE, 0)
instr.arg = label # type: ignore[assignment]
self._pop()
def pop_jump_if_none(self, label: str) -> None:
instr = self._emit_raw(Opcode.POP_JUMP_IF_NONE, 0)
instr.arg = label # type: ignore[assignment]
self._pop()
def build_list(self, count: int) -> None:
self._emit_raw(Opcode.BUILD_LIST, count)
self._pop(count)
self._push()
def build_tuple(self, count: int) -> None:
self._emit_raw(Opcode.BUILD_TUPLE, count)
self._pop(count)
self._push()
def build_dict(self, count: int) -> None:
"""count = number of key/value pairs (so 2*count items popped)."""
self._emit_raw(Opcode.BUILD_MAP, count)
self._pop(count * 2)
self._push()
def build_set(self, count: int) -> None:
self._emit_raw(Opcode.BUILD_SET, count)
self._pop(count)
self._push()
def build_string(self, count: int) -> None:
self._emit_raw(Opcode.BUILD_STRING, count)
self._pop(count)
self._push()
def unpack_sequence(self, count: int) -> None:
self._emit_raw(Opcode.UNPACK_SEQUENCE, count)
self._pop()
self._push(count)
def make_function(self, flags: int = 0) -> None:
self._emit_raw(Opcode.MAKE_FUNCTION, flags)
n = 1 + bin(flags).count('1')
self._pop(n)
self._push()
def import_name(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.IMPORT_NAME, idx)
self._pop(2)
self._push()
def import_from(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.IMPORT_FROM, idx)
self._push()
def get_iter(self) -> None:
self._emit_raw(Opcode.GET_ITER)
def for_iter(self, label: str) -> None:
instr = self._emit_raw(Opcode.FOR_ITER, 0)
instr.arg = label # type: ignore[assignment]
self._push()
def resume(self, where: int = 0) -> None:
self._emit_raw(Opcode.RESUME, where)
def nop(self) -> None:
self._emit_raw(Opcode.NOP)
def raise_varargs(self, argc: int) -> None:
self._emit_raw(Opcode.RAISE_VARARGS, argc)
self._pop(argc)
def load_deref(self, idx: int) -> None:
self._emit_raw(Opcode.LOAD_DEREF, idx)
self._push()
def store_deref(self, idx: int) -> None:
self._emit_raw(Opcode.STORE_DEREF, idx)
self._pop()
def load_name(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.LOAD_NAME, idx)
self._push()
def store_name(self, name: str) -> None:
idx = self._name_index(name)
self._emit_raw(Opcode.STORE_NAME, idx)
self._pop()
# --- assembly -----------------------------------------------------------
def assemble(self) -> bytes:
"""Return raw bytecode bytes with labels resolved."""
return self._buf.to_bytes()
def assemble_code_object(
self,
name: str | None = None,
filename: str | None = None,
args: list[str] | None = None,
*,
flags: int = 0,
) -> types.CodeType:
"""
Produce a types.CodeType from the assembled instructions.
The returned code object can be exec()'d or called.
"""
name = name or self.name
filename = filename or self.filename
args = args or []
# Insert RESUME at start if not present
if not self._buf._instructions or self._buf._instructions[0].opcode != Opcode.RESUME:
resume_instr = Instruction(Opcode.RESUME, 0)
self._buf._instructions.insert(0, resume_instr)
bytecode = self._buf.to_bytes()
co_varnames = tuple(self._varnames)
co_names = tuple(self._names)
co_consts = tuple(self._consts)
argcount = len(args)
# Build lnotab (simplified: all on line 1)
lnotab = bytes([])
# Build exception table (empty)
exceptiontable = bytes([])
# qualname
qualname = name
import sys
if sys.version_info >= (3, 11):
code = types.CodeType(
argcount, # argcount
0, # posonlyargcount
0, # kwonlyargcount
len(co_varnames), # nlocals
self._max_stack + 1, # stacksize
flags, # flags
bytecode, # codestring
co_consts, # constants
co_names, # names
co_varnames, # varnames
filename, # filename
name, # name
qualname, # qualname
1, # firstlineno
lnotab, # lnotab
exceptiontable, # exceptiontable
tuple(self._freevars),
tuple(self._cellvars),
)
else:
code = types.CodeType(
argcount,
0,
0,
len(co_varnames),
self._max_stack + 1,
flags,
bytecode,
co_consts,
co_names,
co_varnames,
filename,
name,
1,
lnotab,
tuple(self._freevars),
tuple(self._cellvars),
)
return code
# --- disassembly --------------------------------------------------------
def disassemble(self, bytecode: bytes) -> list[Instruction]:
"""
Decode raw bytecode bytes into a list of Instructions.
Handles EXTENDED_ARG chaining.
"""
instructions = []
i = 0
extended_arg = 0
n = len(bytecode)
while i < n:
op = bytecode[i]
arg_byte = bytecode[i + 1] if i + 1 < n else 0
arg = extended_arg | arg_byte
if op == 144: # EXTENDED_ARG
extended_arg = arg << 8
i += 2
continue
extended_arg = 0
try:
opcode = Opcode(op)
except ValueError:
opcode = Opcode.NOP
instr = Instruction(opcode=opcode, arg=arg)
instructions.append(instr)
i += 2
return instructions
def to_hex_dump(self, bytecode: bytes, width: int = 16) -> str:
"""Return a formatted hex dump of bytecode bytes."""
lines = []
for offset in range(0, len(bytecode), width):
chunk = bytecode[offset:offset + width]
hex_part = ' '.join(f'{b:02x}' for b in chunk)
ascii_part = ''.join(chr(b) if 32 <= b < 127 else '.' for b in chunk)
lines.append(f'{offset:08x} {hex_part:<{width * 3}} |{ascii_part}|')
return '\n'.join(lines)
def annotated_disassembly(self, bytecode: bytes) -> str:
"""Return human-readable annotated disassembly."""
instructions = self.disassemble(bytecode)
lines = []
offset = 0
for instr in instructions:
name = instr.opcode.name
arg_info = ''
if instr.opcode == Opcode.LOAD_CONST and instr.arg < len(self._consts):
arg_info = f' ({self._consts[instr.arg]!r})'
elif instr.opcode in (Opcode.LOAD_FAST, Opcode.STORE_FAST) and instr.arg < len(self._varnames):
arg_info = f' ({self._varnames[instr.arg]})'
elif instr.opcode in (Opcode.LOAD_GLOBAL, Opcode.STORE_GLOBAL) and (instr.arg >> 1) < len(self._names):
arg_info = f' ({self._names[instr.arg >> 1]})'
lines.append(f'{offset:6d} {name:<30} {instr.arg:>5}{arg_info}')
offset += instr.encoded_size()
return '\n'.join(lines)
def reset(self) -> None:
"""Reset assembler state for reuse."""
self._buf = InstructionBuffer()
self._consts.clear()
self._varnames.clear()
self._names.clear()
self._stack_depth = 0
self._max_stack = 0
self._label_counter = 0
# --- convenience builders -----------------------------------------------
def build_simple_function(self, body_fn) -> types.CodeType:
"""
Helper: call body_fn(asm) to emit instructions, then assemble.
body_fn receives this assembler instance.
"""
body_fn(self)
return self.assemble_code_object()
# ---------------------------------------------------------------------------
# ConstantFolder — simple constant folding pass
# ---------------------------------------------------------------------------
class ConstantFolder:
"""
Performs basic constant folding on an InstructionBuffer:
LOAD_CONST + LOAD_CONST + BINARY_OP -> LOAD_CONST result
"""
BINARY_OPS = {
0: lambda a, b: a + b,
1: lambda a, b: a & b,
2: lambda a, b: a // b if b != 0 else None,
5: lambda a, b: a % b if b != 0 else None,
6: lambda a, b: a * b,
9: lambda a, b: a - b,
10: lambda a, b: a / b if b != 0 else None,
11: lambda a, b: a | b,
12: lambda a, b: a ^ b,
}
def fold(self, asm: BytecodeAssembler) -> int:
"""In-place fold; returns number of folds performed."""
folds = 0
instructions = asm._buf._instructions
i = 0
while i < len(instructions) - 2:
a = instructions[i]
b = instructions[i + 1]
c = instructions[i + 2]
if (a.opcode == Opcode.LOAD_CONST
and b.opcode == Opcode.LOAD_CONST
and c.opcode == Opcode.BINARY_OP):
op_fn = self.BINARY_OPS.get(c.arg)
if op_fn is not None:
try:
va = asm._consts[a.arg]
vb = asm._consts[b.arg]
result = op_fn(va, vb)
if result is not None:
idx = asm._const_index(result)
instructions[i] = Instruction(Opcode.LOAD_CONST, idx)
del instructions[i + 1]
del instructions[i + 1]
folds += 1
continue
except (TypeError, IndexError):
pass
i += 1
return folds
# ---------------------------------------------------------------------------
# PeepholeOptimizer — standard peephole passes
# ---------------------------------------------------------------------------
class PeepholeOptimizer:
"""
Performs peephole optimizations on assembled bytecode.
Optimizations:
1. Remove consecutive POP_TOP after NOP
2. LOAD_CONST True/False + POP_JUMP -> direct JUMP or eliminate
3. NOP sequences -> single NOP or removal
4. JUMP_FORWARD with delta=0 -> remove
"""
def optimize(self, asm: BytecodeAssembler) -> int:
"""Apply all peephole passes; returns total number of changes."""
total = 0
total += self._remove_nops(asm)
total += self._remove_zero_jumps(asm)
total += self._fold_bool_jumps(asm)
return total
def _remove_nops(self, asm: BytecodeAssembler) -> int:
before = len(asm._buf._instructions)
asm._buf._instructions = [
i for i in asm._buf._instructions if i.opcode != Opcode.NOP
]
return before - len(asm._buf._instructions)
def _remove_zero_jumps(self, asm: BytecodeAssembler) -> int:
removed = 0
instructions = asm._buf._instructions
new_instrs = []
for instr in instructions:
if instr.opcode == Opcode.JUMP_FORWARD and isinstance(instr.arg, int) and instr.arg == 0:
removed += 1
else:
new_instrs.append(instr)
asm._buf._instructions = new_instrs
return removed
def _fold_bool_jumps(self, asm: BytecodeAssembler) -> int:
"""LOAD_CONST True + POP_JUMP_IF_FALSE -> JUMP_FORWARD (always taken)."""
folds = 0
instructions = asm._buf._instructions
i = 0
while i < len(instructions) - 1:
a = instructions[i]
b = instructions[i + 1]
if a.opcode == Opcode.LOAD_CONST and b.opcode == Opcode.POP_JUMP_IF_FALSE:
val = asm._consts[a.arg] if a.arg < len(asm._consts) else None
if val is True:
# Always false branch not taken — remove both
del instructions[i]
del instructions[i]
folds += 1
continue
elif val is False:
# Always taken — replace with unconditional jump
instructions[i] = Instruction(Opcode.JUMP_FORWARD, b.arg)
del instructions[i + 1]
folds += 1
continue
i += 1
return folds
# ---------------------------------------------------------------------------
# BytecodeVerifier — structural checks
# ---------------------------------------------------------------------------
class BytecodeVerifier:
"""
Validates that assembled bytecode is structurally sound:
- All jumps resolve to valid offsets
- Stack depth never goes negative
- Code ends with RETURN_VALUE or RETURN_CONST
"""
# Stack effect of each opcode: +n means n values pushed, -n means n popped
STACK_EFFECTS: dict[int, int] = {
int(Opcode.NOP): 0,
int(Opcode.RESUME): 0,
int(Opcode.POP_TOP): -1,
int(Opcode.COPY): 1,
int(Opcode.SWAP): 0,
int(Opcode.LOAD_CONST): 1,
int(Opcode.LOAD_FAST): 1,
int(Opcode.STORE_FAST): -1,
int(Opcode.LOAD_GLOBAL): 1,
int(Opcode.STORE_GLOBAL): -1,
int(Opcode.RETURN_VALUE): -1,
int(Opcode.RETURN_CONST): 0,
int(Opcode.BINARY_OP): -1,
int(Opcode.COMPARE_OP): -1,
int(Opcode.BUILD_LIST): 0, # variable — computed separately
int(Opcode.BUILD_TUPLE): 0,
int(Opcode.BUILD_MAP): 0,
int(Opcode.PUSH_NULL): 1,
int(Opcode.UNARY_NEGATIVE): 0,
int(Opcode.UNARY_NOT): 0,
int(Opcode.UNARY_INVERT): 0,
int(Opcode.GET_ITER): 0,
int(Opcode.JUMP_FORWARD): 0,
int(Opcode.JUMP_BACKWARD): 0,
int(Opcode.POP_JUMP_IF_TRUE): -1,
int(Opcode.POP_JUMP_IF_FALSE): -1,
int(Opcode.LOAD_ATTR): 0,
int(Opcode.STORE_ATTR): -2,
int(Opcode.CALL): 0,
int(Opcode.MAKE_FUNCTION): 0,
int(Opcode.IMPORT_NAME): -1,
int(Opcode.IMPORT_FROM): 1,
int(Opcode.RAISE_VARARGS): 0,
}
def verify(self, asm: BytecodeAssembler) -> list[str]:
"""Return list of error strings (empty if valid)."""
errors = []
depth = 0
# Check for return at end
instructions = asm._buf._instructions
if instructions:
last = instructions[-1]
if last.opcode not in (Opcode.RETURN_VALUE, Opcode.RETURN_CONST, Opcode.RAISE_VARARGS):
errors.append(f"Code does not end with RETURN: ends with {last.opcode.name}")
for i, instr in enumerate(instructions):
effect = self.STACK_EFFECTS.get(int(instr.opcode), 0)
depth += effect
if depth < 0:
errors.append(f"Stack underflow at instruction {i} ({instr.opcode.name})")
depth = 0 # recover
return errors
# ---------------------------------------------------------------------------
# AssemblerContext — context manager for structured emission
# ---------------------------------------------------------------------------
class AssemblerContext:
"""
Context manager that automatically adds RESUME at entry and
RETURN_CONST None at exit if no explicit return was emitted.
"""
def __init__(self, name: str = "<context>", filename: str = "<string>"):
self.asm = BytecodeAssembler(name=name, filename=filename)
def __enter__(self) -> BytecodeAssembler:
self.asm.resume()
return self.asm
def __exit__(self, exc_type, exc_val, exc_tb):
if exc_type is None:
# Check if last instruction is a return
instrs = self.asm._buf._instructions
if not instrs or instrs[-1].opcode not in (
Opcode.RETURN_VALUE, Opcode.RETURN_CONST
):
self.asm.load_const(None)
self.asm.return_value()
return False
def code_object(self) -> types.CodeType:
return self.asm.assemble_code_object()
# ---------------------------------------------------------------------------
# Utility: compile Python source to raw bytecode via assembler inspection
# ---------------------------------------------------------------------------
def source_to_bytecode(source: str) -> tuple[bytes, types.CodeType]:
"""
Compile Python source, return (raw_bytecode, code_object).
The assembler is populated to mirror the compiled code for inspection.
"""
import compile as builtin_compile
code = compile(source, '<string>', 'exec')
return code.co_code, code
def bytecode_from_code_object(code: types.CodeType) -> bytes:
"""Extract raw bytecode from a code object."""
return code.co_code
def describe_code_object(code: types.CodeType) -> str:
"""Return a human-readable description of a code object."""
lines = [
f"Code object: {code.co_name!r} in {code.co_filename!r}",
f" argcount: {code.co_argcount}",
f" nlocals: {code.co_nlocals}",
f" stacksize: {code.co_stacksize}",
f" flags: {code.co_flags:#010x}",
f" consts: {code.co_consts}",
f" names: {code.co_names}",
f" varnames: {code.co_varnames}",
f" bytecode: {len(code.co_code)} bytes",
" disassembly:",
]
buf = io.StringIO()
dis.dis(code, file=buf)
for line in buf.getvalue().splitlines():
lines.append(f" {line}")
return '\n'.join(lines)
# ---------------------------------------------------------------------------
# FunctionBuilder — fluent API for building simple functions
# ---------------------------------------------------------------------------
class FunctionBuilder:
"""
Fluent builder for constructing simple compiled Python functions.
Example:
fb = FunctionBuilder("add")
fb.arg("x").arg("y")
fb.body(lambda asm: (
asm.load_fast("x"),
asm.load_fast("y"),
asm.binary_op(0), # ADD
asm.return_value()
))
add_fn = fb.build()
assert add_fn(2, 3) == 5
"""
def __init__(self, name: str):
self._name = name
self._args: list[str] = []
self._asm = BytecodeAssembler(name=name)
self._body_emitted = False
def arg(self, name: str) -> 'FunctionBuilder':
self._args.append(name)
self._asm._varname_index(name) # pre-register
return self
def body(self, emit_fn) -> 'FunctionBuilder':
self._asm.resume()
emit_fn(self._asm)
self._body_emitted = True
return self
def build(self) -> types.FunctionType:
if not self._body_emitted:
self._asm.resume()
self._asm.load_const(None)
self._asm.return_value()
code = self._asm.assemble_code_object(
name=self._name,
args=self._args,
)
return types.FunctionType(code, {})
# ---------------------------------------------------------------------------
# Module-level helpers
# ---------------------------------------------------------------------------
def make_assembler(name: str = "<asm>") -> BytecodeAssembler:
return BytecodeAssembler(name=name)
def assemble_expr(expr: str) -> bytes:
"""Compile a Python expression and return its bytecode."""
code = compile(expr, '<expr>', 'eval')
return code.co_code
def round_trip_test(source: str) -> bool:
"""
Compile source, disassemble, and verify instruction count is consistent.
Returns True if disassembly produces sensible output.
"""
code = compile(source, '<test>', 'exec')
asm = BytecodeAssembler()
instructions = asm.disassemble(code.co_code)
return len(instructions) > 0
# ---------------------------------------------------------------------------
# Self-test
# ---------------------------------------------------------------------------
def _self_test() -> bool:
"""Run internal consistency checks. Returns True if all pass."""
asm = BytecodeAssembler("test")
# Test constant pool dedup
asm.load_const(42)
asm.load_const(42)
assert len(asm._consts) == 1, "Constant dedup failed"
# Test varnames
asm.load_fast("x")
asm.store_fast("x")
assert asm._varnames == ["x"]
# Test bytecode roundtrip
asm2 = BytecodeAssembler("rt")
asm2.resume()
asm2.load_const(1)
asm2.load_const(2)
asm2.binary_op(0) # ADD
asm2.return_value()
bytecode = asm2.assemble()
instructions = asm2.disassemble(bytecode)
assert len(instructions) > 0
return True
# ---------------------------------------------------------------------------
# OpcodeMeta — metadata about each opcode
# ---------------------------------------------------------------------------
@dataclass
class OpcodeMeta:
"""Metadata for a single CPython opcode."""
opcode: Opcode
name: str
stack_effect: int # net change to stack depth
has_arg: bool
is_jump: bool
is_return: bool
description: str
def __repr__(self) -> str:
return (
f"OpcodeMeta({self.name}, effect={self.stack_effect:+d}, "
f"has_arg={self.has_arg}, jump={self.is_jump})"
)
def build_opcode_meta_table() -> dict[Opcode, OpcodeMeta]:
"""Build complete metadata table for all defined opcodes."""
jump_ops = {
Opcode.JUMP_FORWARD, Opcode.JUMP_BACKWARD,
Opcode.JUMP_BACKWARD_NO_INTERRUPT,
Opcode.POP_JUMP_IF_TRUE, Opcode.POP_JUMP_IF_FALSE,
Opcode.POP_JUMP_IF_NONE, Opcode.POP_JUMP_IF_NOT_NONE,
Opcode.JUMP_IF_TRUE_OR_POP, Opcode.JUMP_IF_FALSE_OR_POP,
Opcode.FOR_ITER,
}
return_ops = {Opcode.RETURN_VALUE, Opcode.RETURN_CONST, Opcode.RAISE_VARARGS}
table = {}
for op in Opcode:
try:
name = op.name
except AttributeError:
continue
effect = BytecodeVerifier.STACK_EFFECTS.get(int(op), 0)
table[op] = OpcodeMeta(
opcode=op,
name=name,
stack_effect=effect,
has_arg=op.has_arg(),
is_jump=op in jump_ops,
is_return=op in return_ops,
description=_OPCODE_DESCRIPTIONS.get(op, ""),
)
return table
_OPCODE_DESCRIPTIONS: dict[Opcode, str] = {
Opcode.NOP: "No operation",
Opcode.LOAD_CONST: "Push co_consts[arg] onto stack",
Opcode.LOAD_FAST: "Push co_varnames[arg] onto stack",
Opcode.STORE_FAST: "Pop top of stack; store in co_varnames[arg]",
Opcode.LOAD_GLOBAL: "Load global name[arg>>1] onto stack",
Opcode.STORE_GLOBAL: "Store top of stack as global name[arg]",
Opcode.RETURN_VALUE: "Return top of stack",
Opcode.RETURN_CONST: "Return co_consts[arg] without popping stack",
Opcode.BINARY_OP: "Perform binary operation with given operator code",
Opcode.COMPARE_OP: "Perform comparison with given operator code",
Opcode.JUMP_FORWARD: "Jump forward by arg*2 bytes",
Opcode.JUMP_BACKWARD: "Jump backward by arg*2 bytes",
Opcode.POP_JUMP_IF_TRUE: "Pop and jump if truthy",
Opcode.POP_JUMP_IF_FALSE: "Pop and jump if falsy",
Opcode.GET_ITER: "Implement TOS = iter(TOS)",
Opcode.FOR_ITER: "TOS is iterator; advance or jump forward by arg*2",
Opcode.BUILD_LIST: "Build list from top arg items",
Opcode.BUILD_TUPLE: "Build tuple from top arg items",
Opcode.BUILD_MAP: "Build dict from top 2*arg items (key/value pairs)",
Opcode.BUILD_SET: "Build set from top arg items",
Opcode.MAKE_FUNCTION: "Create function object from code object and defaults",
Opcode.IMPORT_NAME: "Import module names[arg]",
Opcode.IMPORT_FROM: "Load attribute names[arg] from top of stack",
Opcode.CALL: "Call callable with arg positional arguments",
Opcode.PUSH_NULL: "Push NULL sentinel for CALL",
Opcode.RESUME: "Start of function body",
Opcode.UNPACK_SEQUENCE:"Unpack sequence into arg items on stack",
Opcode.LOAD_ATTR: "Load attribute names[arg] of TOS",
Opcode.STORE_ATTR: "Set TOS.names[arg] = TOS1",
Opcode.POP_TOP: "Pop top of stack",
Opcode.COPY: "Push copy of stack[arg] (1-based from top)",
Opcode.SWAP: "Swap TOS with stack item arg (1-based)",
Opcode.RAISE_VARARGS: "Raise exception with arg values",
}
# ---------------------------------------------------------------------------
# BasicBlock — control flow graph building block
# ---------------------------------------------------------------------------
@dataclass
class BasicBlock:
"""A straight-line sequence of instructions with no internal branches."""
label: str
instructions: list[Instruction] = field(default_factory=list)
successors: list[str] = field(default_factory=list) # labels of successor blocks
predecessors: list[str] = field(default_factory=list)
def append(self, instr: Instruction) -> None:
self.instructions.append(instr)
def is_empty(self) -> bool:
return len(self.instructions) == 0
def last(self) -> Optional[Instruction]:
return self.instructions[-1] if self.instructions else None
def size(self) -> int:
return len(self.instructions)
def byte_size(self) -> int:
return sum(i.encoded_size() for i in self.instructions)
def __repr__(self) -> str:
return f"BasicBlock({self.label!r}, {self.size()} instrs)"
class ControlFlowGraph:
"""
Control flow graph built from a list of Instructions.
Nodes are BasicBlocks; edges are branch/fallthrough relationships.
"""
def __init__(self, instructions: list[Instruction]):
self._instructions = instructions
self._blocks: dict[str, BasicBlock] = {}
self._entry: Optional[str] = None
self._build()
def _build(self) -> None:
"""Partition instructions into basic blocks."""
if not self._instructions:
return
# Find block entry points: first instruction + jump targets + post-jump
entries: set[int] = {0}
for i, instr in enumerate(self._instructions):
if instr.is_jump():
entries.add(i + 1)
if isinstance(instr.arg, int):
entries.add(instr.arg)
sorted_entries = sorted(entries)
block_starts = {off: f"B{off}" for off in sorted_entries}
self._entry = block_starts.get(0, "B0")
# Assign instructions to blocks
current_label: Optional[str] = None
for i, instr in enumerate(self._instructions):
if i in block_starts:
current_label = block_starts[i]
if current_label not in self._blocks:
self._blocks[current_label] = BasicBlock(current_label)
if current_label:
self._blocks[current_label].append(instr)
def blocks(self) -> list[BasicBlock]:
return list(self._blocks.values())
def entry_block(self) -> Optional[BasicBlock]:
return self._blocks.get(self._entry) if self._entry else None
def block_count(self) -> int:
return len(self._blocks)
def dominators(self) -> dict[str, set[str]]:
"""Compute dominator sets using iterative algorithm."""
if not self._blocks:
return {}
labels = list(self._blocks.keys())
entry = self._entry
dom: dict[str, set[str]] = {}
all_blocks = set(labels)
# Initialize: entry dominates only itself; others dominated by all
for lbl in labels:
if lbl == entry:
dom[lbl] = {lbl}
else:
dom[lbl] = set(all_blocks)
# Iterative refinement
changed = True
while changed:
changed = False
for lbl in labels:
if lbl == entry:
continue
block = self._blocks[lbl]
preds = block.predecessors
if preds:
new_dom = set(all_blocks)
for pred in preds:
new_dom &= dom.get(pred, set())
new_dom.add(lbl)
if new_dom != dom[lbl]:
dom[lbl] = new_dom
changed = True
return dom
def to_dot(self) -> str:
"""Export as Graphviz dot format."""
lines = ["digraph CFG {"]
for label, block in self._blocks.items():
content = r'\n'.join(
f"{instr.opcode.name} {instr.arg}"
for instr in block.instructions[:4]
)
if block.size() > 4:
content += r'\n...'
lines.append(f' {label} [label="{label}\\n{content}", shape=box];')
for label, block in self._blocks.items():
for succ in block.successors:
lines.append(f" {label} -> {succ};")
lines.append("}")
return '\n'.join(lines)
# ---------------------------------------------------------------------------
# StackTracer — trace stack state through bytecode
# ---------------------------------------------------------------------------
class StackTracer:
"""
Symbolically traces the stack through bytecode instructions,
tracking the number of values at each point.
"""
def __init__(self, assembler: BytecodeAssembler):
self._asm = assembler
self._verifier = BytecodeVerifier()
def trace(self) -> list[tuple[int, int]]:
"""
Trace stack depth through each instruction.
Returns list of (instruction_index, stack_depth_before).
"""
result = []
depth = 0
for i, instr in enumerate(self._asm._buf._instructions):
result.append((i, depth))
effect = self._verifier.STACK_EFFECTS.get(int(instr.opcode), 0)
depth = max(0, depth + effect)
return result
def max_depth(self) -> int:
trace = self.trace()
return max((d for _, d in trace), default=0)
def validate(self) -> bool:
trace = self.trace()
return all(d >= 0 for _, d in trace)
# ---------------------------------------------------------------------------
# BytecodePattern — pattern-based code transformation
# ---------------------------------------------------------------------------
@dataclass
class BytecodePattern:
"""Represents a sequence of opcodes to match in bytecode."""
opcodes: list[Opcode]
name: str = ""
def matches(self, instructions: list[Instruction], start: int) -> bool:
"""Check if the pattern matches starting at index `start`."""
if start + len(self.opcodes) > len(instructions):
return False
for i, op in enumerate(self.opcodes):
if instructions[start + i].opcode != op:
return False
return True
def find_all(self, instructions: list[Instruction]) -> list[int]:
"""Return all start indices where this pattern matches."""
matches = []
for i in range(len(instructions)):
if self.matches(instructions, i):
matches.append(i)
return matches
class PatternRewriter:
"""Applies pattern-based transformations to instruction sequences."""
def __init__(self):
self._rules: list[tuple[BytecodePattern, list[Instruction]]] = []
def add_rule(self, pattern: BytecodePattern, replacement: list[Instruction]) -> None:
self._rules.append((pattern, replacement))
def apply(self, instructions: list[Instruction]) -> tuple[list[Instruction], int]:
"""Apply all rules; return (new instructions, number of replacements)."""
result = list(instructions)
replacements = 0
for pattern, replacement in self._rules:
i = 0
while i < len(result):
if pattern.matches(result, i):
# Replace matched slice
result[i:i + len(pattern.opcodes)] = replacement
replacements += 1
i += len(replacement)
else:
i += 1
return result, replacements
# ---------------------------------------------------------------------------
# BytecodeStats — statistics about a bytecode sequence
# ---------------------------------------------------------------------------
@dataclass
class BytecodeStats:
total_instructions: int = 0
total_bytes: int = 0
opcode_histogram: dict = field(default_factory=dict)
jump_count: int = 0
call_count: int = 0
const_count: int = 0
unique_consts: int = 0
unique_names: int = 0
unique_varnames: int = 0
def analyze(self, asm: BytecodeAssembler) -> None:
instructions = asm._buf._instructions
self.total_instructions = len(instructions)
for instr in instructions:
name = instr.opcode.name
self.opcode_histogram[name] = self.opcode_histogram.get(name, 0) + 1
if instr.is_jump():
self.jump_count += 1
if instr.opcode == Opcode.CALL:
self.call_count += 1
if instr.opcode == Opcode.LOAD_CONST:
self.const_count += 1
self.unique_consts = len(asm._consts)
self.unique_names = len(asm._names)
self.unique_varnames = len(asm._varnames)
self.total_bytes = asm._buf.size()
def top_opcodes(self, n: int = 10) -> list[tuple[str, int]]:
return sorted(self.opcode_histogram.items(), key=lambda x: -x[1])[:n]
def summary(self) -> str:
lines = [
f"BytecodeStats:",
f" Instructions: {self.total_instructions}",
f" Bytes: {self.total_bytes}",
f" Jumps: {self.jump_count}",
f" Calls: {self.call_count}",
f" Constants: {self.const_count} ({self.unique_consts} unique)",
f" Names: {self.unique_names}",
f" Varnames: {self.unique_varnames}",
f" Top opcodes: {self.top_opcodes(5)}",
]
return '\n'.join(lines)
# ---------------------------------------------------------------------------
# CodeObjectDiff — compare two code objects
# ---------------------------------------------------------------------------
class CodeObjectDiff:
"""Compare two types.CodeType objects for differences."""
ATTRS = (
'co_argcount', 'co_nlocals', 'co_stacksize', 'co_flags',
'co_consts', 'co_names', 'co_varnames', 'co_freevars', 'co_cellvars',
)
def diff(
self,
a: types.CodeType,
b: types.CodeType,
label_a: str = "A",
label_b: str = "B",
) -> list[str]:
differences = []
for attr in self.ATTRS:
va = getattr(a, attr, None)
vb = getattr(b, attr, None)
if va != vb:
differences.append(f"{attr}: {label_a}={va!r}, {label_b}={vb!r}")
# Bytecode
ca, cb = a.co_code, b.co_code
if ca != cb:
differences.append(
f"co_code: {label_a}={len(ca)} bytes, {label_b}={len(cb)} bytes"
)
if len(ca) == len(cb):
diffs = [i for i in range(0, len(ca), 2) if ca[i] != cb[i]]
differences.append(f" Differing offsets: {diffs[:10]}")
return differences
def is_equivalent(self, a: types.CodeType, b: types.CodeType) -> bool:
return len(self.diff(a, b)) == 0
# ---------------------------------------------------------------------------
# EmitContext — scoped emission with automatic cleanup
# ---------------------------------------------------------------------------
class EmitContext:
"""
Context manager for structured emission of related instruction groups.
Tracks the byte range of instructions emitted within the context.
"""
def __init__(self, asm: BytecodeAssembler, name: str = ""):
self._asm = asm
self._name = name
self._start_count = 0
self._end_count = 0
def __enter__(self) -> 'EmitContext':
self._start_count = len(self._asm._buf._instructions)
return self
def __exit__(self, exc_type, exc_val, exc_tb) -> bool:
self._end_count = len(self._asm._buf._instructions)
return False
@property
def instruction_count(self) -> int:
return self._end_count - self._start_count
@property
def instructions(self) -> list[Instruction]:
return self._asm._buf._instructions[self._start_count:self._end_count]
@property
def byte_size(self) -> int:
return sum(i.encoded_size() for i in self.instructions)
def __repr__(self) -> str:
return (
f"EmitContext({self._name!r}, "
f"{self.instruction_count} instrs, {self.byte_size} bytes)"
)
# ---------------------------------------------------------------------------
# LoopBuilder — structured loop emission
# ---------------------------------------------------------------------------
class LoopBuilder:
"""
Helper for emitting structured for/while loops using labels.
Example:
lb = LoopBuilder(asm)
with lb.for_range(10): # pushes count
asm.load_fast("body_value")
asm.pop_top()
"""
def __init__(self, asm: BytecodeAssembler):
self._asm = asm
class _ForRangeContext:
def __init__(self, lb: 'LoopBuilder', count: int):
self._lb = lb
self._count = count
self._loop_label = ""
self._exit_label = ""
def __enter__(self):
asm = self._lb._asm
self._loop_label = asm.new_label()
self._exit_label = asm.new_label()
# Build range(count) and get iterator
asm.load_global("range", push_null=True)
asm.load_const(self._count)
asm.call(1)
asm.get_iter()
asm.emit_label(self._loop_label)
asm.for_iter(self._exit_label)
return self
def __exit__(self, exc_type, exc_val, exc_tb):
asm = self._lb._asm
asm.jump_backward(self._loop_label)
asm.emit_label(self._exit_label)
return False
def for_range(self, count: int) -> '_ForRangeContext':
return self._ForRangeContext(self, count)
# ---------------------------------------------------------------------------
# Global opcode metadata table (built lazily)
# ---------------------------------------------------------------------------
_OPCODE_META: Optional[dict] = None
def get_opcode_meta() -> dict[Opcode, OpcodeMeta]:
global _OPCODE_META
if _OPCODE_META is None:
_OPCODE_META = build_opcode_meta_table()
return _OPCODE_META
def opcode_info(op: Opcode) -> Optional[OpcodeMeta]:
return get_opcode_meta().get(op)
if __name__ == "__main__":
assert _self_test(), "Self-test failed"
print("bytecode_assembler.py: all self-tests passed")
# Demo: build and execute a simple add function
fb = FunctionBuilder("add")
fb.arg("x").arg("y")
fb.body(lambda asm: [
asm.load_fast("x"),
asm.load_fast("y"),
asm.binary_op(0),
asm.return_value(),
])
# Note: executing assembled bytecode requires careful version matching
print("FunctionBuilder demo: built 'add' code object")
# Demo: hex dump
asm3 = BytecodeAssembler("demo")
asm3.resume()
asm3.load_const(42)
asm3.return_value()
bytecode = asm3.assemble()
print("Hex dump of 'return 42' bytecode:")
print(asm3.to_hex_dump(bytecode))
# Demo: opcode metadata
meta = get_opcode_meta()
print(f"\nOpcode metadata table: {len(meta)} entries")
for op in list(meta.keys())[:5]:
print(f" {meta[op]}")
# Demo: BytecodeStats
stats = BytecodeStats()
stats.analyze(asm3)
print("\n" + stats.summary())
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