RustPython/crates/compiler-core/src/bytecode.rs at c0c1218869e59303eb37374f3315816a1295567f · ShaharNaveh/RustPython

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//! Implement python as a virtual machine with bytecode. This module

//! implements bytecode structure.

use crate::{

marshal::MarshalError,

varint::{read_varint, read_varint_with_start, write_varint_be, write_varint_with_start},

{OneIndexed, SourceLocation},

};

use alloc::{borrow::ToOwned, boxed::Box, collections::BTreeSet, fmt, string::String, vec::Vec};

use bitflags::bitflags;

use core::{

cell::UnsafeCell,

hash, mem,

ops::{Deref, Index, IndexMut},

sync::atomic::{AtomicU8, AtomicU16, AtomicUsize, Ordering},

};

use itertools::Itertools;

use malachite_bigint::BigInt;

use num_complex::Complex64;

use rustpython_wtf8::{Wtf8, Wtf8Buf};

pub use crate::bytecode::{

instruction::{

AnyInstruction, AnyOpcode, Arg, Instruction, InstructionMetadata, Opcode,

PseudoInstruction, PseudoOpcode, StackEffect,

oparg::{

BinaryOperator, BuildSliceArgCount, CommonConstant, ComparisonOperator, ConvertValueOparg,

IntrinsicFunction1, IntrinsicFunction2, Invert, Label, LoadAttr, LoadSuperAttr,

MakeFunctionFlag, MakeFunctionFlags, NameIdx, OpArg, OpArgByte, OpArgState, OpArgType,

RaiseKind, SpecialMethod, UnpackExArgs,

};

mod instruction;

pub mod oparg;

/// Exception table entry for zero-cost exception handling

/// Format: (start, size, target, depth<<1|lasti)

#[derive(Clone, Copy, Debug, PartialEq, Eq)]

pub struct ExceptionTableEntry {

/// Start instruction offset (inclusive)

pub start: u32,

/// End instruction offset (exclusive)

pub end: u32,

/// Handler target offset

pub target: u32,

/// Stack depth at handler entry

pub depth: u16,

/// Whether to push lasti before exception

pub push_lasti: bool,

}

impl ExceptionTableEntry {

pub const fn new(start: u32, end: u32, target: u32, depth: u16, push_lasti: bool) -> Self {

Self {

start,

end,

target,

depth,

push_lasti,

}

/// Encode exception table entries.

/// Uses 6-bit varint encoding with start marker (MSB) and continuation bit.

pub fn encode_exception_table(entries: &[ExceptionTableEntry]) -> alloc::boxed::Box<[u8]> {

let mut data = Vec::new();

for entry in entries {

let size = entry.end.saturating_sub(entry.start);

let depth_lasti = ((entry.depth as u32) << 1) | (entry.push_lasti as u32);

write_varint_with_start(&mut data, entry.start);

write_varint_be(&mut data, size);

write_varint_be(&mut data, entry.target);

write_varint_be(&mut data, depth_lasti);

}

data.into_boxed_slice()

}

/// Find exception handler for given instruction offset.

pub fn find_exception_handler(table: &[u8], offset: u32) -> Option<ExceptionTableEntry> {

let mut pos = 0;

while pos < table.len() {

let start = read_varint_with_start(table, &mut pos)?;

let size = read_varint(table, &mut pos)?;

let class=pl-en>read_varint(table, &mut pos)?;

let depth_lasti = read_varint(table, &mut pos)?;

let end = start + size;

let depth = (depth_lasti >> 1) as u16;

let push_lasti = (depth_lasti & 1) != 0;

if offset >= start && offset < end {

return Some(ExceptionTableEntry {

start,

end,

target,

depth,

push_lasti,

});

}

None

}

/// Decode all exception table entries.

pub fn decode_exception_table(table: &[u8]) -> Vec<ExceptionTableEntry> {

let mut entries = Vec::new();

let mut pos = 0;

while pos < table.len() {

let Some(start) = read_varint_with_start(table, &mut pos) else {

break;

};

let Some(size) = read_varint(table, &mut pos) else {

break;

};

let Some(target) = read_varint(table, &mut pos) else {

break;

};

let Some(depth_lasti) = read_varint(table, &mut pos) else {

break;

};

let Some(end) = start.checked_add(size) else {

break;

};

entries.push(ExceptionTableEntry {

start,

end,

target,

depth: (depth_lasti >> 1) as u16,

push_lasti: (depth_lasti & 1) != 0,

});

}

entries

}

/// Parse linetable to build a boolean mask indicating which code units

/// have NO_LOCATION (line == -1). Returns a Vec<bool> of length `num_units`.

pub fn build_no_location_mask(linetable: &[u8], num_units: usize) -> Vec<bool> {

let mut mask = Vec::new();

mask.resize(num_units, false);

let mut pos = 0;

let mut unit_idx = 0;

while pos < linetable.len() && unit_idx < num_units {

let header = linetable[pos];

pos += 1;

let code = (header >> 3) & 0xf;

let length = ((header & 7) + 1) as usize;

let is_no_location = code == PyCodeLocationInfoKind::None as u8;

// Skip payload bytes based on location kind

match code {

0..=9 => pos += 1, // Short forms: 1 byte payload

10..=12 => pos += 2, // OneLine forms: 2 bytes payload

13 => {

// NoColumns: signed varint (line delta)

while pos < linetable.len() {

let b = linetable[pos];

pos += 1;

if b & 0x40 == 0 {

break;

}

14 => {

// Long form: signed varint (line delta) + 3 unsigned varints

// line_delta

while pos < linetable.len() {

let b = linetable[pos];

pos += 1;

if b & 0x40 == 0 {

break;

}

// end_line_delta, col+1, end_col+1

for _ in 0..3 {

while pos < linetable.len() {

let b = linetable[pos];

pos += 1;

if b & 0x40 == 0 {

break;

}

15 => {} // None: no payload

_ => {}

}

for _ in 0..length {

if unit_idx < num_units {

mask[unit_idx] = is_no_location;

unit_idx += 1;

}

mask

}

/// CPython 3.11+ linetable location info codes

#[derive(Copy, Clone, Debug, PartialEq, Eq)]

#[repr(u8)]

pub enum PyCodeLocationInfoKind {

// Short forms are 0 to 9

Short0 = 0,

Short1 = 1,

Short2 = 2,

Short3 = 3,

Short4 = 4,

Short5 = 5,

Short6 = 6,

Short7 = 7,

Short8 = 8,

Short9 = 9,

// One line forms are 10 to 12

OneLine0 = 10,

OneLine1 = 11,

OneLine2 = 12,

NoColumns = 13,

Long = 14,

None = 15,

}

impl PyCodeLocationInfoKind {

pub fn from_code(code: u8) -> Option<Self> {

match code {

0 => Some(Self::Short0),

1 => Some(Self::Short1),

2 => Some(Self::Short2),

3 => Some(Self::Short3),

4 => Some(Self::Short4),

5 => Some(Self::Short5),

6 => Some(Self::Short6),

7 => Some(Self::Short7),

8 => Some(Self::Short8),

9 => Some(Self::Short9),

10 => Some(Self::OneLine0),

11 => Some(Self::OneLine1),

12 => Some(Self::OneLine2),

13 => Some(Self::NoColumns),

14 => Some(Self::Long),

15 => Some(Self::None),

_ => Option::None,

}

pub fn is_short(&self) -> bool {

(*self as u8) <= 9

}

pub fn short_column_group(&self) -> Option<u8> {

if self.is_short() {

Some(*self as u8)

} else {

Option::None

}

pub fn one_line_delta(&self) -> Option<i32> {

match self {

Self::OneLine0 => Some(0),

Self::OneLine1 => Some(1),

Self::OneLine2 => Some(2),

_ => Option::None,

}

pub trait Constant: Sized + Clone {

type Name: AsRef<str>;

/// Transforms the given Constant to a BorrowedConstant

fn borrow_constant(&self) -> BorrowedConstant<'_, Self>;

}

impl Constant for ConstantData {

type Name = String;

fn borrow_constant(&self) -> BorrowedConstant<'_, Self> {

use BorrowedConstant::*;

match self {

Self::Integer { value } => Integer { value },

Self::Float { value } => Float { value: *value },

Self::Complex { value } => Complex { value: *value },

Self::Boolean { value } => Boolean { value: *value },

Self::Str { value } => Str { value },

Self::Bytes { value } => Bytes { value },

Self::Code { code } => Code { code },

Self::Tuple { elements } => Tuple { elements },

Self::Slice { elements } => Slice { elements },

Self::Frozenset { elements } => Frozenset { elements },

Self::None => None,

Self::Ellipsis => Ellipsis,

}

/// A Constant Bag

pub trait ConstantBag: Sized + Copy {

type Constant: Constant;

fn make_constant<C: Constant>(&self, constant: BorrowedConstant<'_, C>) -> Self::Constant;

fn make_int(&self, value: BigInt) -> Self::Constant;

fn make_tuple(&self, elements: impl Iterator<Item = Self::Constant>) -> Self::Constant;

fn make_code(&self, code: CodeObject<Self::Constant>) -> Self::Constant;

fn make_name(&self, name: &str) -> <Self::Constant as Constant>::Name;

}

pub trait AsBag {

type Bag: ConstantBag;

#[allow(clippy::wrong_self_convention)]

fn as_bag(self) -> Self::Bag;

}

impl<Bag: ConstantBag> AsBag for Bag {

type Bag = Self;

fn as_bag(self) -> Self {

self

}

#[derive(Clone, Copy)]

pub struct BasicBag;

impl ConstantBag for BasicBag {

type Constant = ConstantData;

fn make_constant<C: Constant>(&self, constant: BorrowedConstant<'_, C>) -> Self::Constant {

constant.to_owned()

}

fn make_int(&self, value: BigInt) -> Self::Constant {

ConstantData::Integer { value }

}

fn make_tuple(&self, elements: impl Iterator<Item = Self::Constant>) -> Self::Constant {

ConstantData::Tuple {

elements: elements.collect(),

}

fn make_code(&self, code: CodeObject<Self::Constant>) -> Self::Constant {

ConstantData::Code {

code: Box::new(code),

}

fn make_name(&self, name: &str) -> <Self::Constant as Constant>::Name {

name.to_owned()

}

#[derive(Clone)]

pub struct Constants<C: Constant>(Box<[C]>);

impl<C: Constant> Deref for Constants<C> {

type Target = [C];

fn deref(&self) -> &Self::Target {

&self.0

}

impl<C: Constant> Index<oparg::ConstIdx> for Constants<C> {

type Output = C;

fn index(&self, consti: oparg::ConstIdx) -> &Self::Output {

&self.0[consti.as_usize()]

}

impl<C: Constant> FromIterator<C> for Constants<C> {

fn from_iter<T: IntoIterator<Item = C>>(iter: T) -> Self {

Self(iter.into_iter().collect())

}

// TODO: Newtype "CodeObject.varnames". Make sure only `oparg:VarNum` can be used as index

impl<T> Index<oparg::VarNum> for [T] {

type Output = T;

fn index(&self, var_num: oparg::VarNum) -> &Self::Output {

&self[var_num.as_usize()]

}

// TODO: Newtype "CodeObject.varnames". Make sure only `oparg:VarNum` can be used as index

impl<T> IndexMut<oparg::VarNum> for [T] {

fn index_mut(&mut self, var_num: oparg::VarNum) -> &mut Self::Output {

&mut self[var_num.as_usize()]

}

/// Per-slot kind flags for localsplus (co_localspluskinds).

pub const CO_FAST_HIDDEN: u8 = 0x10;

pub const CO_FAST_LOCAL: u8 = 0x20;

pub const CO_FAST_CELL: u8 = 0x40;

pub const CO_FAST_FREE: u8 = 0x80;

/// Primary container of a single code object. Each python function has

/// a code object. Also a module has a code object.

#[derive(Clone)]

pub struct CodeObject<C: Constant = ConstantData> {

pub instructions: CodeUnits,

pub locations: Box<[(SourceLocation, SourceLocation)]>,

pub flags: CodeFlags,

/// Number of positional-only arguments

pub posonlyarg_count: u32,

pub arg_count: u32,

pub kwonlyarg_count: u32,

pub source_path: C::Name,

pub first_line_number: Option<OneIndexed>,

pub max_stackdepth: u32,

/// Name of the object that created this code object

pub obj_name: C::Name,

/// Qualified name of the object (like CPython's co_qualname)

pub qualname: C::Name,

pub constants: Constants<C>,

pub names: Box<[C::Name]>,

pub varnames: Box<[C::Name]>,

pub cellvars: Box<[C::Name]>,

pub freevars: Box<[C::Name]>,

/// Per-slot kind flags: CO_FAST_LOCAL, CO_FAST_CELL, CO_FAST_FREE, CO_FAST_HIDDEN.

/// Length = nlocalsplus (nlocals + ncells + nfrees).

pub localspluskinds: Box<[u8]>,

/// Line number table (CPython 3.11+ format)

pub linetable: Box<[u8]>,

/// Exception handling table

pub exceptiontable: Box<[u8]>,

}

bitflags! {

#[derive(Copy, Clone, Debug, PartialEq)]

pub struct CodeFlags: u32 {

const OPTIMIZED = 0x0001;

const NEWLOCALS = 0x0002;

const VARARGS = 0x0004;

const VARKEYWORDS = 0x0008;

const NESTED = 0x0010;

const GENERATOR = 0x0020;

const COROUTINE = 0x0080;

const ITERABLE_COROUTINE = 0x0100;

/// If a code object represents a function and has a docstring,

/// this bit is set and the first item in co_consts is the docstring.

const HAS_DOCSTRING = 0x4000000;

}

#[repr(C)]

#[derive(Copy, Clone, Debug)]

pub struct CodeUnit {

pub op: Instruction,

pub arg: OpArgByte,

}

const _: () = assert!(mem::size_of::<CodeUnit>() == 2);

/// Adaptive specialization: number of executions before attempting specialization.

///

/// Matches CPython's `_Py_BackoffCounter` encoding.

pub const ADAPTIVE_WARMUP_VALUE: u16 = adaptive_counter_bits(1, 1);

/// Adaptive specialization: cooldown counter after a successful specialization.

///

/// Value/backoff = (52, 0), matching CPython's ADAPTIVE_COOLDOWN bits.

pub const ADAPTIVE_COOLDOWN_VALUE: u16 = adaptive_counter_bits(52, 0);

/// Initial JUMP_BACKWARD counter bits (value/backoff = 4095/12).

pub const JUMP_BACKWARD_INITIAL_VALUE: u16 = adaptive_counter_bits(4095, 12);

const BACKOFF_BITS: u16 = 4;

const MAX_BACKOFF: u16 = 12;

const UNREACHABLE_BACKOFF: u16 = 15;

/// Encode an adaptive counter as `(value << 4) | backoff`.

pub const fn adaptive_counter_bits(value: u16, backoff: u16) -> u16 {

(value << BACKOFF_BITS) | backoff

}

/// True when the adaptive counter should trigger specialization.

#[inline]

pub const fn adaptive_counter_triggers(counter: u16) -> bool {

counter < UNREACHABLE_BACKOFF

}

/// Decrement adaptive counter by one countdown step.

#[inline]

pub const fn advance_adaptive_counter(counter: u16) -> u16 {

counter.wrapping_sub(1 << BACKOFF_BITS)

}

/// Reset adaptive counter with exponential backoff.

#[inline]

pub const fn adaptive_counter_backoff(counter: u16) -> u16 {

let backoff = counter & ((1 << BACKOFF_BITS) - 1);

if backoff < MAX_BACKOFF {

adaptive_counter_bits((1 << (backoff + 1)) - 1, backoff + 1)

} else {

adaptive_counter_bits((1 << MAX_BACKOFF) - 1, MAX_BACKOFF)

}

impl CodeUnit {

pub const fn new(op: Instruction, arg: OpArgByte) -> Self {

Self { op, arg }

}

impl TryFrom<&[u8]> for CodeUnit {

type Error = MarshalError;

fn try_from(value: &[u8]) -> Result<Self, Self::Error> {

match value.len() {

2 => Ok(Self::new(value[0].try_into()?, value[1].into())),

_ => Err(Self::Error::InvalidBytecode),

}

pub struct CodeUnits {

units: UnsafeCell<Box<[CodeUnit]>>,

adaptive_counters: Box<[AtomicU16]>,

/// Pointer-sized cache entries for descriptor pointers.

/// Single atomic load/store prevents torn reads when multiple threads

/// specialize the same instruction concurrently.

pointer_cache: Box<[AtomicUsize]>,

}

// SAFETY: All cache operations use atomic read/write instructions.

// - replace_op / compare_exchange_op: AtomicU8 store/CAS (Release)

// - cache read/write: AtomicU16 load/store (Relaxed)

// - adaptive counter: AtomicU16 load/store (Relaxed)

// Ordering is established by:

// - replace_op (Release) ↔ dispatch loop read_op (Acquire) for cache data visibility

// - tp_version_tag (Acquire) for descriptor pointer validity

unsafe impl Sync for CodeUnits {}

impl Clone for CodeUnits {

fn clone(&self) -> Self {

// SAFETY: No concurrent mutation during clone — cloning is only done

// during code object construction or marshaling, not while instrumented.

let units = unsafe { &*self.units.get() }.clone();

let adaptive_counters = self

.adaptive_counters

.iter()

.map(|c| AtomicU16::new(c.load(Ordering::Relaxed)))

.collect();

let pointer_cache = self

.pointer_cache

.iter()

.map(|c| AtomicUsize::new(c.load(Ordering::Relaxed)))

.collect();

Self {

units: UnsafeCell::new(units),

adaptive_counters,

pointer_cache,

}

impl fmt::Debug for CodeUnits {

fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

// SAFETY: Debug formatting doesn't race with replace_op

let inner = unsafe { &*self.units.get() };

f.debug_tuple("CodeUnits").field(inner).finish()

}

impl TryFrom<&[u8]> for CodeUnits {

type Error = MarshalError;

fn try_from(value: &[u8]) -> Result<Self, Self::Error> {

if !value.len().is_multiple_of(2) {

return Err(Self::Error::InvalidBytecode);

}

let units = value

.chunks_exact(2)

.map(CodeUnit::try_from)

.collect::<Result<Vec<_>, _>>()?;

Ok(units.into())

}

impl<const N: usize> From<[CodeUnit; N]> for CodeUnits {

fn from(value: [CodeUnit; N]) -> Self {

Self::from(Vec::from(value))

}

impl From<Vec<CodeUnit>> for CodeUnits {

fn from(value: Vec<CodeUnit>) -> Self {

let units = value.into_boxed_slice();

let len = units.len();

let adaptive_counters = (0..len)

.map(|_| AtomicU16::new(0))

.collect::<Vec<_>>()

.into_boxed_slice();

let pointer_cache = (0..len)

.map(|_| AtomicUsize::new(0))

.collect::<Vec<_>>()

.into_boxed_slice();

Self {

units: UnsafeCell::new(units),

adaptive_counters,

pointer_cache,

}

impl FromIterator<CodeUnit> for CodeUnits {

fn from_iter<T: IntoIterator<Item = CodeUnit>>(iter: T) -> Self {

Self::from(iter.into_iter().collect::<Vec<_>>())

}

impl Deref for CodeUnits {

type Target = [CodeUnit];

fn deref(&self) -> &Self::Target {

// SAFETY: Shared references to the slice are valid even while replace_op

// may update individual opcode bytes — readers tolerate stale opcodes

// (they will re-read on the next iteration).

unsafe { &*self.units.get() }

}

impl CodeUnits {

/// Disable adaptive specialization by setting all counters to unreachable.

/// Used for CPython-compiled bytecode where specialization may not be safe.

pub fn disable_specialization(&self) {

for counter in self.adaptive_counters.iter() {

counter.store(UNREACHABLE_BACKOFF, Ordering::Relaxed);

}

/// Replace the opcode at `index` in-place without changing the arg byte.

/// Uses atomic Release store to ensure prior cache writes are visible

/// to threads that subsequently read the new opcode with Acquire.

///

/// # Safety

/// - `index` must be in bounds.

/// - `new_op` must have the same arg semantics as the original opcode.

pub unsafe fn replace_op(&self, index: usize, new_op: Instruction) {

let units = unsafe { &*self.units.get() };

let ptr = units.as_ptr().wrapping_add(index) as *const AtomicU8;

unsafe { &*ptr }.store(new_op.into(), Ordering::Release);

}

/// Atomically replace opcode only if it still matches `expected`.

/// Returns true on success. Uses Release ordering on success.

///

/// # Safety

/// - `index` must be in bounds.

pub unsafe fn compare_exchange_op(

&self,

index: usize,

expected: Instruction,

new_op: Instruction,

) -> bool {

let units = unsafe { &*self.units.get() };

let ptr = units.as_ptr().wrapping_add(index) as *const AtomicU8;

unsafe { &*ptr }

.compare_exchange(

expected.into(),

new_op.into(),

Ordering::Release,

Ordering::Relaxed,

)

.is_ok()

}

/// Atomically read the opcode at `index` with Acquire ordering.

/// Pairs with `replace_op` (Release) to ensure cache data visibility.

pub fn read_op(&self, index: usize) -> Instruction {

let units = unsafe { &*self.units.get() };

let ptr = units.as_ptr().wrapping_add(index) as *const AtomicU8;

let byte = unsafe { &*ptr }.load(Ordering::Acquire);

// SAFETY: Only valid Instruction values are stored via replace_op/compare_exchange_op.

unsafe { mem::transmute::<u8, Instruction>(byte) }

}

/// Atomically read the arg byte at `index` with Relaxed ordering.

pub fn read_arg(&self, index: usize) -> OpArgByte {

let units = unsafe { &*self.units.get() };

let ptr = units.as_ptr().wrapping_add(index) as *const u8;

let arg_ptr = unsafe { ptr.add(1) } as *const AtomicU8;

OpArgByte::from(unsafe { &*arg_ptr }.load(Ordering::Relaxed))

}

/// Write a u16 value into a CACHE code unit at `index`.

/// Each CodeUnit is 2 bytes (#[repr(C)]: op u8 + arg u8), so one u16 fits exactly.

/// Uses Relaxed atomic store; ordering is provided by replace_op (Release).

///

/// # Safety

/// - `index` must be in bounds and point to a CACHE entry.

pub unsafe fn write_cache_u16(&self, index: usize, value: u16) {

let units = unsafe { &*self.units.get() };

let ptr = units.as_ptr().wrapping_add(index) as *const AtomicU16;

unsafe { &*ptr }.store(value, Ordering::Relaxed);

}

/// Read a u16 value from a CACHE code unit at `index`.

/// Uses Relaxed atomic load; ordering is provided by read_op (Acquire).

///

/// # Panics

/// Panics if `index` is out of bounds.

pub fn read_cache_u16(&self, index: usize) -> u16 {

let units = unsafe { &*self.units.get() };

assert!(index < units.len(), "read_cache_u16: index out of bounds");

let ptr = units.as_ptr().wrapping_add(index) as *const AtomicU16;

unsafe { &*ptr }.load(Ordering::Relaxed)

}

/// Write a u32 value across two consecutive CACHE code units starting at `index`.

///

/// # Safety

/// Same requirements as `write_cache_u16`.

pub unsafe fn write_cache_u32(&self, index: usize, value: u32) {

unsafe {

self.write_cache_u16(index, value as u16);

self.write_cache_u16(index + 1, (value >> 16) as u16);

}

/// Read a u32 value from two consecutive CACHE code units starting at `index`.

///

/// # Panics

/// Panics if `index + 1` is out of bounds.

pub fn read_cache_u32(&self, index: usize) -> u32 {

let lo = self.read_cache_u16(index) as u32;

let hi = self.read_cache_u16(index + 1) as u32;

lo | (hi << 16)

}

/// Store a pointer-sized value atomically in the pointer cache at `index`.

///

/// Uses a single `AtomicUsize` store to prevent torn writes when

/// multiple threads specialize the same instruction concurrently.

///

/// # Safety

/// - `index` must be in bounds.

/// - `value` must be `0` or a valid `*const PyObject` encoded as `usize`.

/// - Callers must follow the cache invalidation/upgrade protocol:

/// invalidate the version guard before writing and publish the new

/// version after writing.

pub unsafe fn write_cache_ptr(&self, index: usize, value: usize) {

self.pointer_cache[index].store(value, Ordering::Relaxed);

}

/// Load a pointer-sized value atomically from the pointer cache at `index`.

///

/// Uses a single `AtomicUsize` load to prevent torn reads.

///

/// # Panics

/// Panics if `index` is out of bounds.

pub fn read_cache_ptr(&self, index: usize) -> usize {

self.pointer_cache[index].load(Ordering::Relaxed)

}

/// Read adaptive counter bits for instruction at `index`.

/// Uses Relaxed atomic load.

pub fn read_adaptive_counter(&self, index: usize) -> u16 {

self.adaptive_counters[index].load(Ordering::Relaxed)

}

/// Write adaptive counter bits for instruction at `index`.

/// Uses Relaxed atomic store.

///

/// # Safety

/// - `index` must be in bounds.

pub unsafe fn write_adaptive_counter(&self, index: usize, value: u16) {

self.adaptive_counters[index].store(value, Ordering::Relaxed);

}

/// Produce a clean copy of the bytecode suitable for serialization

/// (marshal) and `co_code`. Specialized opcodes are mapped back to their

/// base variants via `deoptimize()` and all CACHE entries are zeroed.

pub fn original_bytes(&self) -> Vec<u8> {

let len = self.len();

let mut out = Vec::with_capacity(len * 2);

let mut i = 0;

while i < len {

let op = self.read_op(i).deoptimize();

let arg = self.read_arg(i);

let caches = op.cache_entries();

out.push(u8::from(op));

out.push(u8::from(arg));

// Zero-fill all CACHE entries (counter + cached data)

for _ in 0..caches {

i += 1;

out.push(0); // op = Cache = 0

out.push(0); // arg = 0

}

i += 1;

}

out

}

/// Initialize adaptive warmup counters for all cacheable instructions.

/// Called lazily at RESUME (first execution of a code object).

/// Counters are stored out-of-line to preserve `op = Instruction::Cache`.

/// All writes are atomic (Relaxed) to avoid data races with concurrent readers.

pub fn quicken(&self) {

let len = self.len();

let mut i = 0;

while i < len {

let op = self.read_op(i);

let caches = op.cache_entries();

if caches > 0 {

// Don't write adaptive counter for instrumented opcodes;

// specialization is skipped while monitoring is active.

if !op.is_instrumented() {

let cache_base = i + 1;

if cache_base < len {

let initial_counter = if matches!(op, Instruction::JumpBackward { .. }) {

JUMP_BACKWARD_INITIAL_VALUE

} else {

ADAPTIVE_WARMUP_VALUE

};

unsafe {

self.write_adaptive_counter(cache_base, initial_counter);

}

i += 1 + caches;

} else {

i += 1;

}

/// A Constant (which usually encapsulates data within it)

///

/// # Examples

/// ```

/// use rustpython_compiler_core::bytecode::ConstantData;

/// let a = ConstantData::Float {value: 120f64};

/// let b = ConstantData::Boolean {value: false};

/// assert_ne!(a, b);

/// ```

#[derive(Debug, Clone)]

pub enum ConstantData {

Tuple {

elements: Vec<ConstantData>,

Integer {

value: BigInt,

Float {

value: f64,

Complex {

value: Complex64,

Boolean {

value: bool,

Str {

value: Wtf8Buf,

Bytes {

value: Vec<u8>,

Code {

code: Box<CodeObject>,

/// Constant slice(start, stop, step)

Slice {

elements: Box<[ConstantData; 3]>,

Frozenset {

elements: Vec<ConstantData>,

None,

Ellipsis,

}

impl PartialEq for ConstantData {

fn eq(&self, other: &Self) -> bool {

use ConstantData::*;

match (self, other) {

(Integer { value: a }, Integer { value: b }) => a == b,

// we want to compare floats *by actual value* - if we have the *exact same* float

// already in a constant cache, we want to use that

(Float { value: a }, Float { value: b }) => a.to_bits() == b.to_bits(),

(Complex { value: a }, Complex { value: b }) => {

a.re.to_bits() == b.re.to_bits() && a.im.to_bits() == b.im.to_bits()

}

(Boolean { value: a }, Boolean { value: b }) => a == b,

(Str { value: a }, Str { value: b }) => a == b,

(Bytes { value: a }, Bytes { value: b }) => a == b,

(Code { code: a }, Code { code: b }) => core::ptr::eq(a.as_ref(), b.as_ref()),

(Tuple { elements: a }, Tuple { elements: b }) => a == b,

(Slice { elements: a }, Slice { elements: b }) => a == b,

(Frozenset { elements: a }, Frozenset { elements: b }) => a == b,

(None, None) => true,

(Ellipsis, Ellipsis) => true,

_ => false,

}

impl Eq for ConstantData {}

impl hash::Hash for ConstantData {

fn hash<H: hash::Hasher>(&self, state: &mut H) {

use ConstantData::*;

mem::discriminant(self).hash(state);

match self {

Integer { value } => value.hash(state),

Float { value } => value.to_bits().hash(state),

Complex { value } => {

value.re.to_bits().hash(state);

value.im.to_bits().hash(state);

}

Boolean { value } => value.hash(state),

Str { value } => value.hash(state),

Bytes { value } => value.hash(state),

Code { code } => core::ptr::hash(code.as_ref(), state),

Tuple { elements } => elements.hash(state),

Slice { elements } => elements.hash(state),

Frozenset { elements } => elements.hash(state),

None => {}

Ellipsis => {}

}

/// A borrowed Constant

pub enum BorrowedConstant<'a, C: Constant> {

Integer { value: &'a BigInt },

Float { value: f64 },

Complex { value: Complex64 },

Boolean { value: bool },

Str { value: &'a Wtf8 },

Bytes { value: &'a [u8] },

Code { code: &'a CodeObject<C> },

Tuple { elements: &'a [C] },

Slice { elements: &'a [C; 3] },

Frozenset { elements: &'a [C] },

None,

Ellipsis,

}

impl<C: Constant> Copy for BorrowedConstant<'_, C> {}

impl<C: Constant> Clone for BorrowedConstant<'_, C> {

fn clone(&self) -> Self {

*self

}

impl<C: Constant> BorrowedConstant<'_, C> {

pub fn fmt_display(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

match self {

BorrowedConstant::Integer { value } => write!(f, "{value}"),

BorrowedConstant::Float { value } => write!(f, "{value}"),

BorrowedConstant::Complex { value } => write!(f, "{value}"),

BorrowedConstant::Boolean { value } => {

write!(f, "{}", if *value { "True" } else { "False" })

}

BorrowedConstant::Str { value } => write!(f, "{value:?}"),

BorrowedConstant::Bytes { value } => write!(f, r#"b"{}""#, value.escape_ascii()),

BorrowedConstant::Code { code } => write!(f, "{code:?}"),

BorrowedConstant::Tuple { elements } => {

write!(f, "(")?;

let mut first = true;

for c in *elements {

if first {

first = false

} else {

write!(f, ", ")?;

}

c.borrow_constant().fmt_display(f)?;

}

write!(f, ")")

}

BorrowedConstant::Slice { elements } => {

write!(f, "slice(")?;

elements[0].borrow_constant().fmt_display(f)?;

write!(f, ", ")?;

elements[1].borrow_constant().fmt_display(f)?;

write!(f, ", ")?;

elements[2].borrow_constant().fmt_display(f)?;

write!(f, ")")

}

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