/
codegen.rs
800 lines (760 loc) · 28.8 KB
/
codegen.rs
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// Copyright (C) 2024 Ryan Daum <ryan.daum@gmail.com>
//
// This program is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free Software
// Foundation, version 3.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/>.
//
/// Takes the AST and turns it into a list of opcodes.
use std::collections::HashMap;
use std::sync::Arc;
use itertools::Itertools;
use tracing::error;
use moor_values::var::Var;
use moor_values::var::Variant;
use crate::ast::{
Arg, BinaryOp, CatchCodes, Expr, ScatterItem, ScatterKind, Stmt, StmtNode, UnaryOp,
};
use crate::builtins::make_builtin_labels;
use crate::labels::{JumpLabel, Label, Name, Names, Offset};
use crate::opcode::Op::Jump;
use crate::opcode::{Op, ScatterArgs, ScatterLabel};
use crate::parse::parse_program;
use crate::program::Program;
use crate::CompileError;
pub struct Loop {
loop_name: Option<Name>,
top_label: Label,
top_stack: Offset,
bottom_label: Label,
bottom_stack: Offset,
}
// Compiler code generation state.
pub struct CodegenState {
pub(crate) ops: Vec<Op>,
pub(crate) jumps: Vec<JumpLabel>,
pub(crate) var_names: Names,
pub(crate) literals: Vec<Var>,
pub(crate) loops: Vec<Loop>,
pub(crate) saved_stack: Option<Offset>,
pub(crate) cur_stack: usize,
pub(crate) max_stack: usize,
pub(crate) builtins: HashMap<String, Name>,
pub(crate) fork_vectors: Vec<Vec<Op>>,
pub(crate) line_number_spans: Vec<(usize, usize)>,
}
impl CodegenState {
pub fn new(var_names: Names, builtins: HashMap<String, Name>) -> Self {
Self {
ops: vec![],
jumps: vec![],
var_names,
literals: vec![],
loops: vec![],
saved_stack: None,
cur_stack: 0,
max_stack: 0,
builtins,
fork_vectors: vec![],
line_number_spans: vec![],
}
}
// Create an anonymous jump label at the current position and return its unique ID.
fn make_jump_label(&mut self, name: Option<Name>) -> Label {
let id = Label(self.jumps.len() as u16);
let position = (self.ops.len()).into();
self.jumps.push(JumpLabel { id, name, position });
id
}
// Adjust the position of a jump label to the current position.
fn commit_jump_label(&mut self, id: Label) {
let position = self.ops.len();
let jump = &mut self
.jumps
.get_mut(id.0 as usize)
.expect("Invalid jump fixup");
let npos = position;
jump.position = npos.into();
}
fn add_literal(&mut self, v: &Var) -> Label {
// This comparison needs to be done with case sensitivity for strings.
let lv_pos = self.literals.iter().position(|lv| lv.eq_case_sensitive(v));
let pos = lv_pos.unwrap_or_else(|| {
let idx = self.literals.len();
self.literals.push(v.clone());
idx
});
Label(pos as u16)
}
fn emit(&mut self, op: Op) {
self.ops.push(op);
}
fn find_loop(&self, loop_label: &Name) -> Result<&Loop, CompileError> {
let Some(l) = self.loops.iter().find(|l| {
if let Some(name) = &l.loop_name {
name.eq(loop_label)
} else {
false
}
}) else {
let loop_name = self.var_names.names[loop_label.0 as usize].clone();
return Err(CompileError::UnknownLoopLabel(loop_name));
};
Ok(l)
}
fn push_stack(&mut self, n: usize) {
self.cur_stack += n;
if self.cur_stack > self.max_stack {
self.max_stack = self.cur_stack;
}
}
fn pop_stack(&mut self, n: usize) {
self.cur_stack -= n;
}
fn saved_stack_top(&self) -> Option<Offset> {
self.saved_stack
}
fn save_stack_top(&mut self) -> Option<Offset> {
let old = self.saved_stack;
self.saved_stack = Some((self.cur_stack - 1).into());
old
}
fn restore_stack_top(&mut self, old: Option<Offset>) {
self.saved_stack = old
}
fn add_fork_vector(&mut self, opcodes: Vec<Op>) -> Offset {
let fv = self.fork_vectors.len();
self.fork_vectors.push(opcodes);
Offset(fv as u16)
}
fn generate_assign(&mut self, left: &Expr, right: &Expr) -> Result<(), CompileError> {
self.push_lvalue(left, false)?;
self.generate_expr(right)?;
match left {
Expr::Range { .. } => self.emit(Op::PutTemp),
Expr::Index(..) => self.emit(Op::PutTemp),
_ => {}
}
let mut is_indexed = false;
let mut e = left;
loop {
// Figure out the form of assignment, handle correctly, then walk through
// chained assignments
match e {
Expr::Range {
base,
from: _,
to: _,
} => {
self.emit(Op::RangeSet);
self.pop_stack(3);
e = base;
is_indexed = true;
continue;
}
Expr::Index(lhs, _rhs) => {
self.emit(Op::IndexSet);
self.pop_stack(2);
e = lhs;
is_indexed = true;
continue;
}
Expr::Id(name) => {
self.emit(Op::Put(*name));
break;
}
Expr::Prop {
location: _,
property: _,
} => {
self.emit(Op::PutProp);
self.pop_stack(2);
break;
}
_ => {
panic!("Bad lvalue in generate_assign")
}
}
}
if is_indexed {
self.emit(Op::Pop);
self.emit(Op::PushTemp);
}
Ok(())
}
fn generate_scatter_assign(
&mut self,
scatter: &[ScatterItem],
right: &Expr,
) -> Result<(), CompileError> {
self.generate_expr(right)?;
let nargs = scatter.len();
let nreq = scatter
.iter()
.filter(|s| s.kind == ScatterKind::Required)
.count();
let nrest = match scatter
.iter()
.positions(|s| s.kind == ScatterKind::Rest)
.last()
{
None => nargs + 1,
Some(rest) => rest + 1,
};
let labels: Vec<(&ScatterItem, ScatterLabel)> = scatter
.iter()
.map(|s| {
let kind_label = match s.kind {
ScatterKind::Required => ScatterLabel::Required(s.id),
ScatterKind::Optional => ScatterLabel::Optional(
s.id,
if s.expr.is_some() {
Some(self.make_jump_label(None))
} else {
None
},
),
ScatterKind::Rest => ScatterLabel::Rest(s.id),
};
(s, kind_label)
})
.collect();
let done = self.make_jump_label(None);
self.emit(Op::Scatter(Box::new(ScatterArgs {
nargs,
nreq,
rest: nrest,
labels: labels.iter().map(|(_, l)| l.clone()).collect(),
done,
})));
for (s, label) in labels {
if let ScatterLabel::Optional(_, Some(label)) = label {
if s.expr.is_none() {
continue;
}
self.commit_jump_label(label);
self.generate_expr(s.expr.as_ref().unwrap())?;
self.emit(Op::Put(s.id));
self.emit(Op::Pop);
self.pop_stack(1);
}
}
self.commit_jump_label(done);
Ok(())
}
fn push_lvalue(&mut self, expr: &Expr, indexed_above: bool) -> Result<(), CompileError> {
match expr {
Expr::Range { from, base, to } => {
self.push_lvalue(base.as_ref(), true)?;
let old = self.save_stack_top();
self.generate_expr(from.as_ref())?;
self.generate_expr(to.as_ref())?;
self.restore_stack_top(old);
}
Expr::Index(lhs, rhs) => {
self.push_lvalue(lhs.as_ref(), true)?;
let old = self.save_stack_top();
self.generate_expr(rhs.as_ref())?;
self.restore_stack_top(old);
if indexed_above {
self.emit(Op::PushRef);
self.push_stack(1);
}
}
Expr::Id(id) => {
if indexed_above {
self.emit(Op::Push(*id));
self.push_stack(1);
}
}
Expr::Prop { property, location } => {
self.generate_expr(location.as_ref())?;
self.generate_expr(property.as_ref())?;
if indexed_above {
self.emit(Op::PushGetProp);
self.push_stack(1);
}
}
_ => {
panic!("Invalid expr for lvalue: {:?}", expr);
}
}
Ok(())
}
fn generate_codes(&mut self, codes: &CatchCodes) -> Result<(), CompileError> {
match codes {
CatchCodes::Codes(codes) => {
self.generate_arg_list(codes)?;
}
CatchCodes::Any => {
self.emit(Op::ImmInt(0));
self.push_stack(1);
}
}
Ok(())
}
fn generate_expr(&mut self, expr: &Expr) -> Result<(), CompileError> {
match expr {
Expr::Value(v) => {
match v.variant() {
Variant::None => {
self.emit(Op::ImmNone);
}
Variant::Obj(oid) => {
self.emit(Op::ImmObjid(*oid));
}
Variant::Int(ref i) => {
if i <= &(i32::MAX as i64) {
self.emit(Op::ImmInt(*i as i32));
} else {
self.emit(Op::ImmBigInt(*i));
}
}
Variant::Err(e) => {
self.emit(Op::ImmErr(*e));
}
_ => {
let literal = self.add_literal(v);
self.emit(Op::Imm(literal));
}
};
self.push_stack(1);
}
Expr::Id(ident) => {
self.emit(Op::Push(*ident));
self.push_stack(1);
}
Expr::And(left, right) => {
self.generate_expr(left.as_ref())?;
let end_label = self.make_jump_label(None);
self.emit(Op::And(end_label));
self.pop_stack(1);
self.generate_expr(right.as_ref())?;
self.commit_jump_label(end_label);
}
Expr::Or(left, right) => {
self.generate_expr(left.as_ref())?;
let end_label = self.make_jump_label(None);
self.emit(Op::Or(end_label));
self.pop_stack(1);
self.generate_expr(right.as_ref())?;
self.commit_jump_label(end_label);
}
Expr::Binary(op, l, r) => {
self.generate_expr(l)?;
self.generate_expr(r)?;
let binop = match op {
BinaryOp::Add => Op::Add,
BinaryOp::Sub => Op::Sub,
BinaryOp::Mul => Op::Mul,
BinaryOp::Div => Op::Div,
BinaryOp::Mod => Op::Mod,
BinaryOp::Eq => Op::Eq,
BinaryOp::NEq => Op::Ne,
BinaryOp::Gt => Op::Gt,
BinaryOp::GtE => Op::Ge,
BinaryOp::Lt => Op::Lt,
BinaryOp::LtE => Op::Le,
BinaryOp::Exp => Op::Exp,
BinaryOp::In => Op::In,
};
self.emit(binop);
self.pop_stack(1);
}
Expr::Index(lhs, rhs) => {
self.generate_expr(lhs.as_ref())?;
let old = self.save_stack_top();
self.generate_expr(rhs.as_ref())?;
self.restore_stack_top(old);
self.emit(Op::Ref);
self.pop_stack(1);
}
Expr::Range { base, from, to } => {
self.generate_expr(base.as_ref())?;
let old = self.save_stack_top();
self.generate_expr(from.as_ref())?;
self.generate_expr(to.as_ref())?;
self.restore_stack_top(old);
self.emit(Op::RangeRef);
self.pop_stack(2);
}
Expr::Length => {
let saved = self.saved_stack_top();
self.emit(Op::Length(saved.expect("Missing saved stack for '$'")));
self.push_stack(1);
}
Expr::Unary(op, expr) => {
self.generate_expr(expr.as_ref())?;
self.emit(match op {
UnaryOp::Neg => Op::UnaryMinus,
UnaryOp::Not => Op::Not,
});
}
Expr::Prop { location, property } => {
self.generate_expr(location.as_ref())?;
self.generate_expr(property.as_ref())?;
self.emit(Op::GetProp);
self.pop_stack(1);
}
Expr::Pass { args } => {
self.generate_arg_list(args)?;
self.emit(Op::Pass);
}
Expr::Call { function, args } => {
// Lookup builtin.
let Some(builtin) = self.builtins.get(function) else {
error!("Unknown builtin function: {}({:?}", function, args);
return Err(CompileError::UnknownBuiltinFunction(function.clone()));
};
let builtin = *builtin;
self.generate_arg_list(args)?;
self.emit(Op::FuncCall { id: builtin });
}
Expr::Verb {
args,
verb,
location,
} => {
self.generate_expr(location.as_ref())?;
self.generate_expr(verb.as_ref())?;
self.generate_arg_list(args)?;
self.emit(Op::CallVerb);
self.pop_stack(2);
}
Expr::Cond {
alternative,
condition,
consequence,
} => {
self.generate_expr(condition.as_ref())?;
let else_label = self.make_jump_label(None);
self.emit(Op::IfQues(else_label));
self.pop_stack(1);
self.generate_expr(consequence.as_ref())?;
let end_label = self.make_jump_label(None);
self.emit(Op::Jump { label: end_label });
self.pop_stack(1);
self.commit_jump_label(else_label);
self.generate_expr(alternative.as_ref())?;
self.commit_jump_label(end_label);
}
Expr::Catch {
codes,
except,
trye,
} => {
self.generate_codes(codes)?;
let handler_label = self.make_jump_label(None);
self.emit(Op::PushLabel(handler_label));
self.emit(Op::Catch(handler_label));
self.generate_expr(trye.as_ref())?;
let end_label = self.make_jump_label(None);
self.emit(Op::EndCatch(end_label));
self.pop_stack(1) /* codes, catch */;
self.commit_jump_label(handler_label);
/* After this label, we still have a value on the stack, but now,
* instead of it being the value of the main expression, we have
* the exception pushed before entering the handler.
*/
match except {
None => {
self.emit(Op::ImmInt(1));
self.emit(Op::Ref);
}
Some(except) => {
self.emit(Op::Pop);
self.pop_stack(1);
self.generate_expr(except.as_ref())?;
}
}
self.commit_jump_label(end_label);
}
Expr::List(l) => {
self.generate_arg_list(l)?;
}
Expr::Scatter(scatter, right) => self.generate_scatter_assign(scatter, right)?,
Expr::Assign { left, right } => self.generate_assign(left, right)?,
}
Ok(())
}
pub fn generate_stmt(&mut self, stmt: &Stmt) -> Result<(), CompileError> {
// We use the 'canonical' tree line number here for span generation, which should match what
// unparse generates.
// TODO In theory we could actually provide both and generate spans for both for situations
// where the user is looking at their own not-decompiled copy of the source.
let line_number = stmt.tree_line_no;
self.line_number_spans.push((self.ops.len(), line_number));
match &stmt.node {
StmtNode::Cond { arms, otherwise } => {
let end_label = self.make_jump_label(None);
let mut is_else = false;
for arm in arms {
self.generate_expr(&arm.condition)?;
let otherwise_label = self.make_jump_label(None);
self.emit(if !is_else {
Op::If(otherwise_label)
} else {
Op::Eif(otherwise_label)
});
is_else = true;
self.pop_stack(1);
for stmt in &arm.statements {
self.generate_stmt(stmt)?;
}
self.emit(Op::Jump { label: end_label });
// This is where we jump to if the condition is false; either the end of the
// if statement, or the start of the next ('else or elseif') arm.
self.commit_jump_label(otherwise_label);
}
if !otherwise.is_empty() {
for stmt in otherwise {
self.generate_stmt(stmt)?;
}
}
self.commit_jump_label(end_label);
}
StmtNode::ForList { id, expr, body } => {
self.generate_expr(expr)?;
// Note that MOO is 1-indexed, so this is counter value is 1 in LambdaMOO;
// we use 0 here to make it easier to implement the ForList instruction.
self.emit(Op::ImmInt(0)); /* loop list index... */
self.push_stack(1);
let loop_top = self.make_jump_label(Some(*id));
self.commit_jump_label(loop_top);
let end_label = self.make_jump_label(Some(*id));
self.emit(Op::ForList { id: *id, end_label });
self.loops.push(Loop {
loop_name: Some(*id),
top_label: loop_top,
top_stack: self.cur_stack.into(),
bottom_label: end_label,
bottom_stack: (self.cur_stack - 2).into(),
});
for stmt in body {
self.generate_stmt(stmt)?;
}
self.emit(Op::Jump { label: loop_top });
self.commit_jump_label(end_label);
self.pop_stack(2);
self.loops.pop();
}
StmtNode::ForRange { from, to, id, body } => {
self.generate_expr(from)?;
self.generate_expr(to)?;
let loop_top = self.make_jump_label(Some(*id));
let end_label = self.make_jump_label(Some(*id));
self.commit_jump_label(loop_top);
self.emit(Op::ForRange { id: *id, end_label });
self.loops.push(Loop {
loop_name: Some(*id),
top_label: loop_top,
top_stack: self.cur_stack.into(),
bottom_label: end_label,
bottom_stack: (self.cur_stack - 2).into(),
});
for stmt in body {
self.generate_stmt(stmt)?;
}
self.emit(Jump { label: loop_top });
self.commit_jump_label(end_label);
self.pop_stack(2);
self.loops.pop();
}
StmtNode::While {
id,
condition,
body,
} => {
let loop_start_label = self.make_jump_label(*id);
self.commit_jump_label(loop_start_label);
let loop_end_label = self.make_jump_label(*id);
self.generate_expr(condition)?;
match id {
None => self.emit(Op::While(loop_end_label)),
Some(id) => self.emit(Op::WhileId {
id: *id,
end_label: loop_end_label,
}),
}
self.pop_stack(1);
self.loops.push(Loop {
loop_name: *id,
top_label: loop_start_label,
top_stack: self.cur_stack.into(),
bottom_label: loop_end_label,
bottom_stack: self.cur_stack.into(),
});
for s in body {
self.generate_stmt(s)?;
}
self.emit(Op::Jump {
label: loop_start_label,
});
self.commit_jump_label(loop_end_label);
self.loops.pop();
}
StmtNode::Fork { id, body, time } => {
self.generate_expr(time)?;
// Stash all of main vector in a temporary buffer, then begin compilation of the forked code.
// Once compiled, we can create a fork vector from the new buffer, and then restore the main vector.
let stashed_ops = std::mem::take(&mut self.ops);
for stmt in body {
self.generate_stmt(stmt)?;
}
self.emit(Op::Done);
let forked_ops = std::mem::take(&mut self.ops);
let fv_id = self.add_fork_vector(forked_ops);
self.ops = stashed_ops;
self.emit(Op::Fork {
id: *id,
fv_offset: fv_id,
});
self.pop_stack(1);
}
StmtNode::TryExcept { body, excepts } => {
let mut labels = vec![];
for ex in excepts {
self.generate_codes(&ex.codes)?;
let push_label = self.make_jump_label(None);
self.emit(Op::PushLabel(push_label));
labels.push(push_label);
}
let num_excepts = excepts.len();
self.emit(Op::TryExcept { num_excepts });
for stmt in body {
self.generate_stmt(stmt)?;
}
let end_label = self.make_jump_label(None);
self.emit(Op::EndExcept(end_label));
self.pop_stack(num_excepts);
for (i, ex) in excepts.iter().enumerate() {
self.commit_jump_label(labels[i]);
self.push_stack(1);
if ex.id.is_some() {
self.emit(Op::Put(ex.id.unwrap()));
}
self.emit(Op::Pop);
self.pop_stack(1);
for stmt in &ex.statements {
self.generate_stmt(stmt)?;
}
if i + 1 < excepts.len() {
self.emit(Op::Jump { label: end_label });
}
}
self.commit_jump_label(end_label);
}
StmtNode::TryFinally { body, handler } => {
let handler_label = self.make_jump_label(None);
self.emit(Op::TryFinally(handler_label));
for stmt in body {
self.generate_stmt(stmt)?;
}
self.emit(Op::EndFinally);
self.commit_jump_label(handler_label);
self.push_stack(2); /* continuation value, reason */
for stmt in handler {
self.generate_stmt(stmt)?;
}
self.emit(Op::Continue);
self.pop_stack(2);
}
StmtNode::Break { exit: None } => {
let l = self.loops.last().expect("No loop to break/continue from");
self.emit(Op::Exit {
stack: l.bottom_stack,
label: l.bottom_label,
})
}
StmtNode::Break { exit: Some(l) } => {
let l = self.find_loop(l).expect("invalid loop for break/continue");
self.emit(Op::ExitId(l.bottom_label));
}
StmtNode::Continue { exit: None } => {
let l = self.loops.last().expect("No loop to break/continue from");
self.emit(Op::Exit {
stack: l.top_stack,
label: l.top_label,
})
}
StmtNode::Continue { exit: Some(l) } => {
let l = self.find_loop(l).expect("invalid loop for break/continue");
self.emit(Op::ExitId(l.top_label));
}
StmtNode::Return(Some(expr)) => {
self.generate_expr(expr)?;
self.emit(Op::Return);
self.pop_stack(1);
}
StmtNode::Return(None) => self.emit(Op::Return0),
StmtNode::Expr(e) => {
self.generate_expr(e)?;
self.emit(Op::Pop);
self.pop_stack(1);
}
}
Ok(())
}
fn generate_arg_list(&mut self, args: &Vec<Arg>) -> Result<(), CompileError> {
// TODO(rdaum): Check recursion down to see if all literal values, and if so reduce to a Imm value with the full list,
// instead of concatenation with MkSingletonList.
if args.is_empty() {
self.emit(Op::ImmEmptyList);
self.push_stack(1);
return Ok(());
}
let mut normal_op = Op::MakeSingletonList;
let mut splice_op = Op::CheckListForSplice;
let mut pop = 0;
for a in args {
match a {
Arg::Normal(a) => {
self.generate_expr(a)?;
self.emit(normal_op.clone());
}
Arg::Splice(s) => {
self.generate_expr(s)?;
self.emit(splice_op.clone());
}
}
self.pop_stack(pop);
pop = 1;
normal_op = Op::ListAddTail;
splice_op = Op::ListAppend;
}
Ok(())
}
}
pub fn compile(program: &str) -> Result<Program, CompileError> {
let compile_span = tracing::trace_span!("compile");
let _compile_guard = compile_span.enter();
let builtins = make_builtin_labels();
let parse = parse_program(program)?;
// Generate the code into 'cg_state'.
let mut cg_state = CodegenState::new(parse.names, builtins);
for x in parse.stmts {
cg_state.generate_stmt(&x)?;
}
cg_state.emit(Op::Done);
if cg_state.cur_stack != 0 || cg_state.saved_stack.is_some() {
panic!(
"Stack is not empty at end of compilation: cur_stack#: {} stack: {:?}",
cg_state.cur_stack, cg_state.saved_stack
)
}
let binary = Program {
literals: cg_state.literals,
jump_labels: cg_state.jumps,
var_names: cg_state.var_names,
main_vector: Arc::new(cg_state.ops),
fork_vectors: cg_state.fork_vectors,
line_number_spans: cg_state.line_number_spans,
};
Ok(binary)
}