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dust/dust-lang/src/chunk.rs

631 lines
19 KiB
Rust

use std::fmt::{self, Debug, Display, Formatter};
use colored::Colorize;
use serde::{Deserialize, Serialize};
use crate::{AnnotatedError, Identifier, Instruction, Operation, Span, Value};
#[derive(Clone)]
pub struct Chunk {
instructions: Vec<(Instruction, Span)>,
constants: Vec<Option<Value>>,
locals: Vec<Local>,
scope_depth: usize,
}
impl Chunk {
pub fn new() -> Self {
Self {
instructions: Vec::new(),
constants: Vec::new(),
locals: Vec::new(),
scope_depth: 0,
}
}
pub fn with_data(
instructions: Vec<(Instruction, Span)>,
constants: Vec<Value>,
locals: Vec<Local>,
) -> Self {
Self {
instructions,
constants: constants.into_iter().map(Some).collect(),
locals,
scope_depth: 0,
}
}
pub fn scope_depth(&self) -> usize {
self.scope_depth
}
pub fn len(&self) -> usize {
self.instructions.len()
}
pub fn is_empty(&self) -> bool {
self.instructions.is_empty()
}
pub fn get_instruction(
&self,
offset: usize,
position: Span,
) -> Result<&(Instruction, Span), ChunkError> {
self.instructions
.get(offset)
.ok_or(ChunkError::CodeIndexOfBounds { offset, position })
}
pub fn remove_instruction(&mut self, index: usize) -> (Instruction, Span) {
self.instructions.remove(index)
}
pub fn push_instruction(&mut self, instruction: Instruction, position: Span) {
self.instructions.push((instruction, position));
}
pub fn insert_instruction(&mut self, index: usize, instruction: Instruction, position: Span) {
self.instructions.insert(index, (instruction, position));
}
pub fn pop_instruction(&mut self, position: Span) -> Result<(Instruction, Span), ChunkError> {
self.instructions
.pop()
.ok_or(ChunkError::InstructionUnderflow { position })
}
pub fn get_last_instruction(&self) -> Result<(&Instruction, &Span), ChunkError> {
let (instruction, position) =
self.instructions
.last()
.ok_or_else(|| ChunkError::InstructionUnderflow {
position: Span(0, 0),
})?;
Ok((instruction, position))
}
pub fn get_last_n_instructions<const N: usize>(&self) -> [Option<&(Instruction, Span)>; N] {
let mut instructions = [None; N];
for i in 0..N {
let index = self.instructions.len().saturating_sub(i + 1);
let instruction = self.instructions.get(index);
instructions[i] = instruction;
}
instructions
}
pub fn find_last_instruction(&mut self, operation: Operation) -> Option<usize> {
self.instructions
.iter()
.enumerate()
.rev()
.find_map(|(index, (instruction, _))| {
if instruction.operation() == operation {
Some(index)
} else {
None
}
})
}
pub fn get_last_operation(&self) -> Result<Operation, ChunkError> {
self.get_last_instruction()
.map(|(instruction, _)| instruction.operation())
}
pub fn get_last_n_operations<const N: usize>(&self) -> [Option<Operation>; N] {
let mut operations = [None; N];
for i in 0..N {
let index = self.instructions.len().saturating_sub(i + 1);
let operation = self
.instructions
.get(index)
.map(|(instruction, _)| instruction.operation());
operations[i] = operation;
}
operations
}
pub fn get_constant(&self, index: u8, position: Span) -> Result<&Value, ChunkError> {
let index = index as usize;
self.constants
.get(index)
.ok_or(ChunkError::ConstantIndexOutOfBounds { index, position })
.and_then(|value| {
value
.as_ref()
.ok_or(ChunkError::ConstantAlreadyUsed { index, position })
})
}
pub fn take_constant(&mut self, index: u8, position: Span) -> Result<Value, ChunkError> {
let index = index as usize;
self.constants
.get_mut(index)
.ok_or_else(|| ChunkError::ConstantIndexOutOfBounds { index, position })?
.take()
.ok_or(ChunkError::ConstantAlreadyUsed { index, position })
}
pub fn push_constant(&mut self, value: Value, position: Span) -> Result<u8, ChunkError> {
let starting_length = self.constants.len();
if starting_length + 1 > (u8::MAX as usize) {
Err(ChunkError::ConstantOverflow { position })
} else {
self.constants.push(Some(value));
Ok(starting_length as u8)
}
}
pub fn locals(&self) -> &[Local] {
&self.locals
}
pub fn get_local(&self, index: u8, position: Span) -> Result<&Local, ChunkError> {
let index = index as usize;
self.locals
.get(index)
.ok_or(ChunkError::LocalIndexOutOfBounds { index, position })
}
pub fn get_identifier(&self, index: u8) -> Option<&Identifier> {
self.locals
.get(index as usize)
.map(|local| &local.identifier)
}
pub fn get_local_index(
&self,
identifier: &Identifier,
position: Span,
) -> Result<u8, ChunkError> {
self.locals
.iter()
.enumerate()
.rev()
.find_map(|(index, local)| {
if &local.identifier == identifier {
Some(index as u8)
} else {
None
}
})
.ok_or(ChunkError::IdentifierNotFound {
identifier: identifier.clone(),
position,
})
}
pub fn declare_local(
&mut self,
identifier: Identifier,
mutable: bool,
register_index: u8,
position: Span,
) -> Result<u8, ChunkError> {
let starting_length = self.locals.len();
if starting_length + 1 > (u8::MAX as usize) {
Err(ChunkError::IdentifierOverflow { position })
} else {
self.locals.push(Local::new(
identifier,
mutable,
self.scope_depth,
Some(register_index),
));
Ok(starting_length as u8)
}
}
pub fn define_local(
&mut self,
local_index: u8,
register_index: u8,
position: Span,
) -> Result<(), ChunkError> {
let local = self.locals.get_mut(local_index as usize).ok_or_else(|| {
ChunkError::LocalIndexOutOfBounds {
index: local_index as usize,
position,
}
})?;
local.register_index = Some(register_index);
Ok(())
}
pub fn begin_scope(&mut self) {
self.scope_depth += 1;
}
pub fn end_scope(&mut self) {
self.scope_depth -= 1;
}
pub fn disassembler<'a>(&'a self, name: &'a str) -> ChunkDisassembler<'a> {
ChunkDisassembler::new(name, self)
}
}
impl Default for Chunk {
fn default() -> Self {
Self::new()
}
}
impl Display for Chunk {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(
f,
"{}",
self.disassembler("Chunk Display")
.styled(true)
.disassemble()
)
}
}
impl Debug for Chunk {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(
f,
"{}",
self.disassembler("Chunk Debug Display")
.styled(false)
.disassemble()
)
}
}
impl Eq for Chunk {}
impl PartialEq for Chunk {
fn eq(&self, other: &Self) -> bool {
self.instructions == other.instructions
&& self.constants == other.constants
&& self.locals == other.locals
}
}
#[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
pub struct Local {
pub identifier: Identifier,
pub mutable: bool,
pub depth: usize,
pub register_index: Option<u8>,
}
impl Local {
pub fn new(
identifier: Identifier,
mutable: bool,
depth: usize,
register_index: Option<u8>,
) -> Self {
Self {
identifier,
mutable,
depth,
register_index,
}
}
}
pub struct ChunkDisassembler<'a> {
name: &'a str,
chunk: &'a Chunk,
width: Option<usize>,
styled: bool,
}
impl<'a> ChunkDisassembler<'a> {
const INSTRUCTION_HEADER: [&'static str; 5] = [
"",
"Instructions",
"------------",
"INDEX BYTECODE OPERATION INFO JUMP POSITION",
"----- -------- --------------- ------------------------- -------- --------",
];
const CONSTANT_HEADER: [&'static str; 5] = [
"",
"Constants",
"---------",
"INDEX VALUE ",
"----- ---------",
];
const LOCAL_HEADER: [&'static str; 5] = [
"",
"Locals",
"------",
"INDEX IDENTIFIER MUTABLE DEPTH REGISTER",
"----- ---------- ------- ----- --------",
];
/// The default width of the disassembly output. To correctly align the output, this should
/// return the width of the longest line that the disassembler is guaranteed to produce.
pub fn default_width() -> usize {
let longest_line = Self::INSTRUCTION_HEADER[4];
longest_line.chars().count()
}
pub fn new(name: &'a str, chunk: &'a Chunk) -> Self {
Self {
name,
chunk,
width: None,
styled: false,
}
}
pub fn width(&mut self, width: usize) -> &mut Self {
self.width = Some(width);
self
}
pub fn styled(&mut self, styled: bool) -> &mut Self {
self.styled = styled;
self
}
pub fn disassemble(&self) -> String {
let width = self.width.unwrap_or_else(Self::default_width);
let center = |line: &str| format!("{line:^width$}\n");
let style = |line: String| {
if self.styled {
line.bold().to_string()
} else {
line
}
};
let mut disassembly = String::with_capacity(self.predict_length());
let name_line = style(center(self.name));
disassembly.push_str(&name_line);
let info_line = center(&format!(
"{} instructions, {} constants, {} locals",
self.chunk.instructions.len(),
self.chunk.constants.len(),
self.chunk.locals.len()
));
let styled_info_line = {
if self.styled {
info_line.dimmed().to_string()
} else {
info_line
}
};
disassembly.push_str(&styled_info_line);
for line in Self::INSTRUCTION_HEADER {
disassembly.push_str(&style(center(line)));
}
for (index, (instruction, position)) in self.chunk.instructions.iter().enumerate() {
let position = position.to_string();
let operation = instruction.operation().to_string();
let (info, jump_offset) = instruction.disassembly_info(Some(self.chunk));
let info = if let Some(info) = info {
info
} else {
" ".to_string()
};
let jump_offset = if let Some(jump_offset) = jump_offset {
let index = index as isize;
let jump_index = index + jump_offset + 1;
format!("{index} -> {jump_index}")
} else {
" ".to_string()
};
let bytecode = u32::from(instruction);
let instruction_display = format!(
"{index:<5} {bytecode:<08X} {operation:15} {info:25} {jump_offset:8} {position:8}"
);
disassembly.push_str(&center(&instruction_display));
}
for line in Self::CONSTANT_HEADER {
disassembly.push_str(&style(center(line)));
}
for (index, value_option) in self.chunk.constants.iter().enumerate() {
let value_display = value_option
.as_ref()
.map(|value| value.to_string())
.unwrap_or("empty".to_string());
let trucated_length = 8;
let with_elipsis = trucated_length - 3;
let constant_display = if value_display.len() > with_elipsis {
format!("{index:<5} {value_display:.<trucated_length$.with_elipsis$}")
} else {
format!("{index:<5} {value_display:<trucated_length$}")
};
disassembly.push_str(&center(&constant_display));
}
for line in Self::LOCAL_HEADER {
disassembly.push_str(&style(center(line)));
}
for (
index,
Local {
identifier,
depth,
register_index,
mutable,
},
) in self.chunk.locals.iter().enumerate()
{
let register_display = register_index
.as_ref()
.map(|value| value.to_string())
.unwrap_or_else(|| "empty".to_string());
let identifier_display = identifier.as_str();
let local_display = format!(
"{index:<5} {identifier_display:10} {mutable:7} {depth:<5} {register_display:8}"
);
disassembly.push_str(&center(&local_display));
}
let expected_length = self.predict_length();
let actual_length = disassembly.len();
if !self.styled && expected_length != actual_length {
log::debug!(
"Chunk disassembly was not optimized correctly, expected string length {expected_length}, got {actual_length}",
);
}
if self.styled && expected_length > actual_length {
log::debug!(
"Chunk disassembly was not optimized correctly, expected string length to be at least{expected_length}, got {actual_length}",
);
}
disassembly
}
/// Predicts the capacity of the disassembled output. This is used to pre-allocate the string
/// buffer to avoid reallocations.
///
/// The capacity is calculated as follows:
/// - Get the number of static lines, i.e. lines that are always present in the disassembly
/// - Get the number of dynamic lines, i.e. lines that are generated from the chunk
/// - Add an one to the width to account for the newline character
/// - Multiply the total number of lines by the width of the disassembly output
///
/// The result is accurate only if the output is not styled. Otherwise the extra bytes added by
/// the ANSI escape codes will make the result too low. It still works as a lower bound in that
/// case.
fn predict_length(&self) -> usize {
const EXTRA_LINES: usize = 2; // There is one info line and one empty line after the name
let static_line_count = Self::INSTRUCTION_HEADER.len()
+ Self::CONSTANT_HEADER.len()
+ Self::LOCAL_HEADER.len()
+ EXTRA_LINES;
let dynamic_line_count =
self.chunk.instructions.len() + self.chunk.constants.len() + self.chunk.locals.len();
let total_line_count = static_line_count + dynamic_line_count;
let width = self.width.unwrap_or_else(Self::default_width) + 1;
total_line_count * width
}
}
#[derive(Debug, Clone, PartialEq)]
pub enum ChunkError {
CodeIndexOfBounds {
offset: usize,
position: Span,
},
ConstantAlreadyUsed {
index: usize,
position: Span,
},
ConstantOverflow {
position: Span,
},
ConstantIndexOutOfBounds {
index: usize,
position: Span,
},
InstructionUnderflow {
position: Span,
},
LocalIndexOutOfBounds {
index: usize,
position: Span,
},
IdentifierOverflow {
position: Span,
},
IdentifierNotFound {
identifier: Identifier,
position: Span,
},
}
impl AnnotatedError for ChunkError {
fn title() -> &'static str {
"Chunk Error"
}
fn description(&self) -> &'static str {
match self {
ChunkError::CodeIndexOfBounds { .. } => "Code index out of bounds",
ChunkError::ConstantAlreadyUsed { .. } => "Constant already used",
ChunkError::ConstantOverflow { .. } => "Constant overflow",
ChunkError::ConstantIndexOutOfBounds { .. } => "Constant index out of bounds",
ChunkError::InstructionUnderflow { .. } => "Instruction underflow",
ChunkError::LocalIndexOutOfBounds { .. } => "Identifier index out of bounds",
ChunkError::IdentifierOverflow { .. } => "Identifier overflow",
ChunkError::IdentifierNotFound { .. } => "Identifier not found",
}
}
fn details(&self) -> Option<String> {
match self {
ChunkError::CodeIndexOfBounds { offset, .. } => Some(format!("Code index: {}", offset)),
ChunkError::ConstantAlreadyUsed { index, .. } => {
Some(format!("Constant index: {}", index))
}
ChunkError::ConstantIndexOutOfBounds { index, .. } => {
Some(format!("Constant index: {}", index))
}
ChunkError::InstructionUnderflow { .. } => None,
ChunkError::LocalIndexOutOfBounds { index, .. } => {
Some(format!("Identifier index: {}", index))
}
ChunkError::IdentifierNotFound { identifier, .. } => {
Some(format!("Identifier: {}", identifier))
}
ChunkError::IdentifierOverflow { .. } => Some("Identifier overflow".to_string()),
ChunkError::ConstantOverflow { .. } => Some("Constant overflow".to_string()),
}
}
fn position(&self) -> Span {
match self {
ChunkError::CodeIndexOfBounds { position, .. } => *position,
ChunkError::ConstantAlreadyUsed { position, .. } => *position,
ChunkError::ConstantIndexOutOfBounds { position, .. } => *position,
ChunkError::IdentifierNotFound { position, .. } => *position,
ChunkError::InstructionUnderflow { position, .. } => *position,
ChunkError::LocalIndexOutOfBounds { position, .. } => *position,
ChunkError::IdentifierOverflow { position, .. } => *position,
ChunkError::ConstantOverflow { position, .. } => *position,
}
}
}