feat(tazjin/rlox): Track source lines along with bytecode

Change-Id: I272e73b9b1c9571fbfe4fa983fb4283ddee02bd4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2414
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
This commit is contained in:
Vincent Ambo 2021-01-17 21:05:05 +03:00 committed by tazjin
parent 49c4cc6c56
commit c26915d012
2 changed files with 40 additions and 3 deletions

View file

@ -11,13 +11,24 @@ use super::value;
#[derive(Debug, Default)]
pub struct Chunk {
code: Vec<OpCode>,
lines: Vec<Span>,
constants: Vec<value::Value>,
}
#[derive(Debug)]
struct Span {
/// Source code line
line: usize,
/// Number of instructions derived from this line
count: usize,
}
impl Chunk {
pub fn add_op(&mut self, data: OpCode) -> usize {
pub fn add_op(&mut self, data: OpCode, line: usize) -> usize {
let idx = self.code.len();
self.code.push(data);
self.add_line(line);
idx
}
@ -26,6 +37,25 @@ impl Chunk {
self.constants.push(data);
idx
}
fn add_line(&mut self, line: usize) {
match self.lines.last_mut() {
Some(span) if span.line == line => span.count += 1,
_ => self.lines.push(Span { line, count: 1 }),
}
}
fn get_line(&self, offset: usize) -> usize {
let mut pos = 0;
for span in &self.lines {
pos += span.count;
if pos > offset {
return span.line;
}
}
panic!("invalid chunk state: line missing for offset {}", offset);
}
}
impl Index<usize> for Chunk {
@ -50,6 +80,13 @@ pub fn disassemble(chunk: &Chunk, name: &str) {
fn disassemble_instruction(chunk: &Chunk, offset: usize) {
print!("{:04} ", offset);
let line = chunk.get_line(offset);
if offset > 0 && line == chunk.get_line(offset - 1) {
print!(" | ");
} else {
print!("{:4} ", line);
}
match &chunk[offset] {
OpCode::OpConstant(idx) => println!("OpConstant idx '{:?}'", chunk.constants[*idx]),
op => println!("{:?}", op),

View file

@ -13,8 +13,8 @@ pub fn main() {
let mut chunk: Chunk = Default::default();
let constant = chunk.add_constant(1.2);
chunk.add_op(OpCode::OpConstant(constant));
chunk.add_op(OpCode::OpReturn);
chunk.add_op(OpCode::OpConstant(constant), 1);
chunk.add_op(OpCode::OpReturn, 1);
chunk::disassemble(&chunk, "test chunk");
}