refactor(downgrade): MaybeThunk

Cargo.lock

@@ -258,6 +258,15 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
 
+[[package]]
+name = "colored"
+version = "3.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "faf9468729b8cbcea668e36183cb69d317348c2e08e994829fb56ebfdfbaac34"
+dependencies = [
+ "windows-sys",
+]
+
 [[package]]
 name = "countme"
 version = "3.0.1"
@@ -451,7 +460,6 @@ dependencies = [
  "mimalloc",
  "rnix",
  "rustyline",
- "smallvec",
  "string-interner",
  "tempfile",
  "test-log",
@@ -472,10 +480,10 @@ dependencies = [
 name = "fix-codegen"
 version = "0.1.0"
 dependencies = [
+ "colored",
  "fix-builtins",
  "fix-common",
  "fix-ir",
- "gc-arena",
  "hashbrown 0.16.1",
  "num_enum",
  "rnix",

Cargo.toml

@@ -14,6 +14,10 @@ members = [
 inherits = "release"
 debug = true
 
+[profile.lto]
+inherits = "release"
+lto = true
+
 [workspace.dependencies]
 bumpalo = { version = "3.20", features = [
     "allocator-api2",

fix-codegen/Cargo.toml

@@ -4,11 +4,11 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-gc-arena = { workspace = true }
 hashbrown = { workspace = true }
 num_enum = { workspace = true }
 rnix = { workspace = true }
 string-interner = { workspace = true }
+colored = "3.1.1"
 
 fix-builtins = { path = "../fix-builtins" }
 fix-common = { path = "../fix-common" }

fix-codegen/src/disassembler.rs

@@ -0,0 +1,366 @@
+use std::fmt::Write;
+
+use colored::Colorize;
+use num_enum::TryFromPrimitive;
+
+use crate::{InstructionPtr, Op};
+
+pub trait DisassemblerContext {
+    fn resolve_string(&self, id: u32) -> &str;
+    fn get_code(&self) -> &[u8];
+}
+
+pub struct Disassembler<'a, Ctx> {
+    code: &'a [u8],
+    ctx: &'a Ctx,
+    pc: usize,
+}
+
+impl<'a, Ctx: DisassemblerContext> Disassembler<'a, Ctx> {
+    pub fn new(ip: InstructionPtr, ctx: &'a Ctx) -> Self {
+        Self {
+            code: ctx.get_code(),
+            ctx,
+            pc: ip.0,
+        }
+    }
+
+    fn read_u8(&mut self) -> u8 {
+        let b = self.code[self.pc];
+        self.pc += 1;
+        b
+    }
+
+    fn read_u16(&mut self) -> u16 {
+        let bytes = self.code[self.pc..self.pc + 2]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 2;
+        u16::from_le_bytes(bytes)
+    }
+
+    fn read_u32(&mut self) -> u32 {
+        let bytes = self.code[self.pc..self.pc + 4]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 4;
+        u32::from_le_bytes(bytes)
+    }
+
+    fn read_i32(&mut self) -> i32 {
+        let bytes = self.code[self.pc..self.pc + 4]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 4;
+        i32::from_le_bytes(bytes)
+    }
+
+    fn read_i64(&mut self) -> i64 {
+        let bytes = self.code[self.pc..self.pc + 8]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 8;
+        i64::from_le_bytes(bytes)
+    }
+
+    fn read_f64(&mut self) -> f64 {
+        let bytes = self.code[self.pc..self.pc + 8]
+            .try_into()
+            .expect("no enough bytes");
+        self.pc += 8;
+        f64::from_le_bytes(bytes)
+    }
+
+    pub fn disassemble(&mut self) -> String {
+        self.disassemble_impl(false)
+    }
+
+    pub fn disassemble_colored(&mut self) -> String {
+        self.disassemble_impl(true)
+    }
+
+    fn disassemble_impl(&mut self, color: bool) -> String {
+        let mut out = String::new();
+        if color {
+            let _ = writeln!(out, "{}", "=== Bytecode Disassembly ===".bold().white());
+            let _ = writeln!(
+                out,
+                "{} {}",
+                "Length:".white(),
+                format!("{} bytes", self.code.len()).cyan()
+            );
+        } else {
+            let _ = writeln!(out, "=== Bytecode Disassembly ===");
+            let _ = writeln!(out, "Length: {} bytes", self.code.len());
+        }
+
+        while self.pc < self.code.len() {
+            let start_pos = self.pc;
+            let op_byte = self.read_u8();
+            let (mnemonic, args) = self.decode_instruction(op_byte, start_pos);
+
+            let bytes_slice = &self.code[start_pos + 1..self.pc];
+            let mut chunks = bytes_slice.chunks(4);
+
+            let first_chunk = chunks.next().unwrap_or(&[]);
+            let bytes_str = {
+                let mut temp = format!("{:02x}", self.code[start_pos]);
+                for b in first_chunk {
+                    let _ = write!(&mut temp, " {:02x}", b);
+                }
+                temp
+            };
+
+            if color {
+                let sep = if args.is_empty() { "" } else { " " };
+                let _ = writeln!(
+                    out,
+                    "{}  {:<14} | {}{}{}",
+                    format!("{:04x}", start_pos).dimmed(),
+                    bytes_str.green(),
+                    mnemonic.yellow().bold(),
+                    sep,
+                    args.cyan()
+                );
+            } else {
+                let op_str = if args.is_empty() {
+                    mnemonic.to_string()
+                } else {
+                    format!("{} {}", mnemonic, args)
+                };
+                let _ = writeln!(out, "{:04x}  {:<14} | {}", start_pos, bytes_str, op_str);
+            }
+
+            for chunk in chunks {
+                let bytes_str = {
+                    let mut temp = String::from("  ");
+                    for b in chunk {
+                        let _ = write!(&mut temp, " {:02x}", b);
+                    }
+                    temp
+                };
+
+                let extra_width = if start_pos > 0 {
+                    start_pos.ilog2() >> 4
+                } else {
+                    0
+                };
+
+                if color {
+                    let _ = write!(out, "    ");
+                    for _ in 0..extra_width {
+                        let _ = write!(out, " ");
+                    }
+                    let _ = writeln!(out, "  {:<14} |", bytes_str.green());
+                } else {
+                    let _ = write!(out, "    ");
+                    for _ in 0..extra_width {
+                        let _ = write!(out, " ");
+                    }
+                    let _ = writeln!(out, "  {:<14} |", bytes_str);
+                }
+            }
+        }
+        out
+    }
+
+    fn decode_instruction(&mut self, op_byte: u8, current_pc: usize) -> (&'static str, String) {
+        let op = Op::try_from_primitive(op_byte).expect("invalid op code");
+
+        match op {
+            Op::PushSmi => {
+                let val = self.read_i32();
+                ("PushSmi", format!("{}", val))
+            }
+            Op::PushBigInt => {
+                let val = self.read_i64();
+                ("PushBigInt", format!("{}", val))
+            }
+            Op::PushFloat => {
+                let val = self.read_f64();
+                ("PushFloat", format!("{}", val))
+            }
+            Op::PushString => {
+                let idx = self.read_u32();
+                let s = self.ctx.resolve_string(idx);
+                let len = s.len();
+                let mut s_fmt = format!("{:?}", s);
+                if s_fmt.len() > 60 {
+                    s_fmt.truncate(57);
+                    #[allow(clippy::unwrap_used)]
+                    write!(s_fmt, "...\" (total {len} bytes)").unwrap();
+                }
+                ("PushString", format!("@{} {}", idx, s_fmt))
+            }
+            Op::PushNull => ("PushNull", String::new()),
+            Op::PushTrue => ("PushTrue", String::new()),
+            Op::PushFalse => ("PushFalse", String::new()),
+
+            Op::LoadLocal => {
+                let idx = self.read_u32();
+                ("LoadLocal", format!("[{}]", idx))
+            }
+            Op::LoadOuter => {
+                let depth = self.read_u8();
+                let idx = self.read_u32();
+                ("LoadOuter", format!("depth={} [{}]", depth, idx))
+            }
+            Op::StoreLocal => {
+                let idx = self.read_u32();
+                ("StoreLocal", format!("[{}]", idx))
+            }
+            Op::AllocLocals => {
+                let count = self.read_u32();
+                ("AllocLocals", format!("count={}", count))
+            }
+
+            Op::MakeThunk => {
+                let offset = self.read_u32();
+                ("MakeThunk", format!("-> {:04x}", offset))
+            }
+            Op::MakeClosure => {
+                let offset = self.read_u32();
+                let slots = self.read_u32();
+                ("MakeClosure", format!("-> {:04x} slots={}", offset, slots))
+            }
+            Op::MakePatternClosure => {
+                let offset = self.read_u32();
+                let slots = self.read_u32();
+                let req_count = self.read_u16();
+                let opt_count = self.read_u16();
+                let ellipsis = self.read_u8() != 0;
+
+                let mut arg_str = format!(
+                    "-> {:04x} slots={} req={} opt={} ...={})",
+                    offset, slots, req_count, opt_count, ellipsis
+                );
+
+                arg_str.push_str(" Args=[");
+                for _ in 0..req_count {
+                    let idx = self.read_u32();
+                    arg_str.push_str(&format!("Req({}) ", self.ctx.resolve_string(idx)));
+                }
+                for _ in 0..opt_count {
+                    let idx = self.read_u32();
+                    arg_str.push_str(&format!("Opt({}) ", self.ctx.resolve_string(idx)));
+                }
+
+                let total_args = req_count + opt_count;
+                for _ in 0..total_args {
+                    let _name_idx = self.read_u32();
+                    let _span_id = self.read_u32();
+                }
+                arg_str.push(']');
+
+                ("MakePatternClosure", arg_str)
+            }
+
+            Op::Call => ("Call", String::new()),
+
+            Op::MakeAttrs => {
+                let count = self.read_u32();
+                ("MakeAttrs", format!("size={}", count))
+            }
+            Op::MakeEmptyAttrs => ("MakeEmptyAttrs", String::new()),
+
+            Op::Select => {
+                let path_len = self.read_u16();
+                let span_id = self.read_u32();
+                ("Select", format!("path_len={} span={}", path_len, span_id))
+            }
+            Op::SelectDefault => {
+                let path_len = self.read_u16();
+                let span_id = self.read_u32();
+                (
+                    "SelectDefault",
+                    format!("path_len={} span={}", path_len, span_id),
+                )
+            }
+            Op::HasAttr => {
+                let path_len = self.read_u16();
+                ("HasAttr", format!("path_len={}", path_len))
+            }
+
+            Op::MakeList => {
+                let count = self.read_u32();
+                ("MakeList", format!("size={}", count))
+            }
+            Op::MakeEmptyList => ("MakeEmptyList", String::new()),
+
+            Op::OpAdd => ("OpAdd", String::new()),
+            Op::OpSub => ("OpSub", String::new()),
+            Op::OpMul => ("OpMul", String::new()),
+            Op::OpDiv => ("OpDiv", String::new()),
+            Op::OpEq => ("OpEq", String::new()),
+            Op::OpNeq => ("OpNeq", String::new()),
+            Op::OpLt => ("OpLt", String::new()),
+            Op::OpGt => ("OpGt", String::new()),
+            Op::OpLeq => ("OpLeq", String::new()),
+            Op::OpGeq => ("OpGeq", String::new()),
+            Op::OpConcat => ("OpConcat", String::new()),
+            Op::OpUpdate => ("OpUpdate", String::new()),
+            Op::OpNeg => ("OpNeg", String::new()),
+            Op::OpNot => ("OpNot", String::new()),
+
+            Op::JumpIfFalse => {
+                let offset = self.read_i32();
+                let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
+                (
+                    "JumpIfFalse",
+                    format!("-> {:04x} offset={}", target, offset),
+                )
+            }
+            Op::JumpIfTrue => {
+                let offset = self.read_i32();
+                let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
+                ("JumpIfTrue", format!("-> {:04x} offset={}", target, offset))
+            }
+            Op::Jump => {
+                let offset = self.read_i32();
+                let target = (current_pc as isize + 1 + 4 + offset as isize) as usize;
+                ("Jump", format!("-> {:04x} offset={}", target, offset))
+            }
+
+            Op::ConcatStrings => {
+                let count = self.read_u16();
+                let force = self.read_u8();
+                ("ConcatStrings", format!("count={} force={}", count, force))
+            }
+            Op::ResolvePath => ("ResolvePath", String::new()),
+            Op::Assert => {
+                let raw_idx = self.read_u32();
+                let span_id = self.read_u32();
+                ("Assert", format!("text_id={} span={}", raw_idx, span_id))
+            }
+            Op::PushWith => ("PushWith", String::new()),
+            Op::PopWith => ("PopWith", String::new()),
+            Op::WithLookup => {
+                let idx = self.read_u32();
+                let name = self.ctx.resolve_string(idx);
+                ("WithLookup", format!("{:?}", name))
+            }
+
+            Op::LoadBuiltins => ("LoadBuiltins", String::new()),
+            Op::LoadBuiltin => {
+                let id = self.read_u8();
+                ("LoadBuiltin", format!("id={}", id))
+            }
+            Op::MkPos => {
+                let span_id = self.read_u32();
+                ("MkPos", format!("id={}", span_id))
+            }
+            Op::LoadReplBinding => {
+                let idx = self.read_u32();
+                let name = self.ctx.resolve_string(idx);
+                ("LoadReplBinding", format!("{:?}", name))
+            }
+            Op::LoadScopedBinding => {
+                let idx = self.read_u32();
+                let name = self.ctx.resolve_string(idx);
+                ("LoadScopedBinding", format!("{:?}", name))
+            }
+            Op::Return => ("Return", String::new()),
+            Op::Illegal => ("Illegal", String::new()),
+        }
+    }
+}

fix-codegen/src/lib.rs

@@ -1,13 +1,15 @@
 use std::ops::Deref;
 
-use fix_builtins::{BUILTINS, BuiltinId};
+use fix_builtins::BuiltinId;
 use fix_common::StringId;
-use fix_ir::{Attr, BinOpKind, Ir, Param, RawIrRef, ThunkId, UnOpKind};
+use fix_ir::{Attr, BinOpKind, Ir, MaybeThunk, Param, RawIrRef, ThunkId, UnOpKind};
 use hashbrown::HashMap;
 use num_enum::TryFromPrimitive;
 use rnix::TextRange;
 use string_interner::Symbol as _;
 
+pub mod disassembler;
+
 pub struct InstructionPtr(pub usize);
 
 pub trait BytecodeContext {
@@ -149,40 +151,34 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         }
     }
 
-    fn classify_value(&mut self, ir: RawIrRef<'_>) -> InlineOperand {
+    fn inline_maybe_thunk(&mut self, val: MaybeThunk) -> InlineOperand {
-        match ir.deref() {
+        use MaybeThunk::*;
-            &Ir::Int(x) => {
+        match val {
+            Int(x) => {
                 if x <= i32::MAX as i64 {
                     InlineOperand::Const(Const::Smi(x as i32))
                 } else {
                     InlineOperand::BigInt(x)
                 }
             }
-            &Ir::Float(x) => InlineOperand::Const(Const::Float(x)),
+            Float(x) => InlineOperand::Const(Const::Float(x)),
-            &Ir::Bool(b) => InlineOperand::Const(Const::Bool(b)),
+            Bool(b) => InlineOperand::Const(Const::Bool(b)),
-            Ir::Null => InlineOperand::Const(Const::Null),
+            Null => InlineOperand::Const(Const::Null),
-            Ir::Str(s) => {
+            Str(id) => InlineOperand::Const(Const::String(id)),
-                let sid = self.ctx.intern_string(s.deref());
+            Thunk(id) => {
-                InlineOperand::Const(Const::String(sid))
-            }
-            &Ir::Thunk(id) => {
                 let (layer, local) = self.resolve_thunk(id);
                 InlineOperand::Local { layer, local }
             }
-            &Ir::Arg { layer } => InlineOperand::Local {
+            Arg { layer } => InlineOperand::Local {
                 layer: layer.try_into().expect("scope too deep!"),
                 local: 0,
             },
-            &Ir::Builtin(id) => {
-                let arity = BUILTINS[id as usize].1;
-                InlineOperand::Const(Const::PrimOp { id, arity })
-            }
-            Ir::Builtins => InlineOperand::Builtins,
             _ => panic!("cannot classify IR node as inline operand"),
         }
     }
 
-    fn emit_inline_operand(&mut self, operand: InlineOperand) {
+    fn emit_maybe_thunk(&mut self, val: MaybeThunk) {
+        let operand = self.inline_maybe_thunk(val);
         match operand {
             InlineOperand::Const(val) => {
                 let idx = self.ctx.add_constant(val);
@@ -318,30 +314,15 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 self.count_with_thunks(*lhs) + self.count_with_thunks(*rhs)
             }
             Ir::UnOp { rhs, .. } => self.count_with_thunks(*rhs),
-            Ir::Call { func, arg, .. } => {
+            Ir::Call { func, .. } => self.count_with_thunks(*func),
-                self.count_with_thunks(*func) + self.count_with_thunks(*arg)
-            }
             Ir::Assert {
                 assertion, expr, ..
             } => self.count_with_thunks(*assertion) + self.count_with_thunks(*expr),
-            Ir::Select { expr, default, .. } => {
+            Ir::Select { expr, .. } => self.count_with_thunks(*expr),
-                self.count_with_thunks(*expr) + default.map_or(0, |d| self.count_with_thunks(d))
-            }
             Ir::HasAttr { lhs, .. } => self.count_with_thunks(*lhs),
             Ir::ConcatStrings { parts, .. } => {
                 parts.iter().map(|p| self.count_with_thunks(*p)).sum()
             }
-            Ir::Path(p) => self.count_with_thunks(*p),
-            Ir::List { items } => items.iter().map(|item| self.count_with_thunks(*item)).sum(),
-            Ir::AttrSet { stcs, dyns } => {
-                stcs.iter()
-                    .map(|(_, &(val, _))| self.count_with_thunks(val))
-                    .sum::<usize>()
-                    + dyns
-                        .iter()
-                        .map(|&(k, v, _)| self.count_with_thunks(k) + self.count_with_thunks(v))
-                        .sum::<usize>()
-            }
             _ => 0,
         }
     }
@@ -390,9 +371,8 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 self.collect_with_thunks_recursive(*rhs, out);
             }
             Ir::UnOp { rhs, .. } => self.collect_with_thunks_recursive(*rhs, out),
-            Ir::Call { func, arg, .. } => {
+            Ir::Call { func, .. } => {
                 self.collect_with_thunks_recursive(*func, out);
-                self.collect_with_thunks_recursive(*arg, out);
             }
             Ir::Assert {
                 assertion, expr, ..
@@ -400,11 +380,8 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 self.collect_with_thunks_recursive(*assertion, out);
                 self.collect_with_thunks_recursive(*expr, out);
             }
-            Ir::Select { expr, default, .. } => {
+            Ir::Select { expr, .. } => {
                 self.collect_with_thunks_recursive(*expr, out);
-                if let Some(d) = default {
-                    self.collect_with_thunks_recursive(*d, out);
-                }
             }
             Ir::HasAttr { lhs, .. } => self.collect_with_thunks_recursive(*lhs, out),
             Ir::ConcatStrings { parts, .. } => {
@@ -412,22 +389,7 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                     self.collect_with_thunks_recursive(*p, out);
                 }
             }
-            Ir::Path(p) => self.collect_with_thunks_recursive(*p, out),
+            _ => (),
-            Ir::List { items } => {
-                for item in items.iter() {
-                    self.collect_with_thunks_recursive(*item, out);
-                }
-            }
-            Ir::AttrSet { stcs, dyns } => {
-                for (_, &(val, _)) in stcs.iter() {
-                    self.collect_with_thunks_recursive(val, out);
-                }
-                for &(key, val, _) in dyns.iter() {
-                    self.collect_with_thunks_recursive(key, out);
-                    self.collect_with_thunks_recursive(val, out);
-                }
-            }
-            _ => {}
         }
     }
 
@@ -510,10 +472,9 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
             &Ir::Bool(true) => self.emit_op(Op::PushTrue),
             &Ir::Bool(false) => self.emit_op(Op::PushFalse),
             Ir::Null => self.emit_op(Op::PushNull),
-            Ir::Str(s) => {
+            &Ir::Str(id) => {
-                let idx = self.ctx.intern_string(s.deref());
                 self.emit_op(Op::PushString);
-                self.emit_str_id(idx);
+                self.emit_str_id(id);
             }
             &Ir::Path(p) => {
                 self.emit_expr(p);
@@ -570,15 +531,14 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                     self.emit_op(Op::MakeList);
                     self.emit_u32(items.len() as u32);
                     for &item in items.iter() {
-                        let operand = self.classify_value(item);
+                        self.emit_maybe_thunk(item);
-                        self.emit_inline_operand(operand);
                     }
                 }
             }
             &Ir::Call { func, arg, .. } => {
-                self.emit_expr(arg);
                 self.emit_expr(func);
                 self.emit_op(Op::Call);
+                self.inline_maybe_thunk(arg);
             }
             &Ir::Arg { layer } => {
                 self.emit_load(layer.try_into().expect("scope too deep!"), 0);
@@ -614,16 +574,17 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
                 );
             }
             &Ir::ConcatStrings {
-                ref parts,
+                parts: _,
-                force_string,
+                force_string: _,
             } => {
-                self.emit_op(Op::ConcatStrings);
+                todo!("redesign ConcatStrings");
-                self.emit_u16(parts.len() as u16);
+                // self.emit_op(Op::ConcatStrings);
-                self.emit_u8(if force_string { 1 } else { 0 });
+                // self.emit_u16(parts.len() as u16);
-                for &part in parts.iter() {
+                // self.emit_u8(if force_string { 1 } else { 0 });
-                    let operand = self.classify_value(part);
+                // for &part in parts.iter() {
-                    self.emit_inline_operand(operand);
+                //     let operand = self.inline_maybe_thunk(part);
-                }
+                //     self.emit_inline_operand(operand);
+                // }
             }
             &Ir::HasAttr { lhs, ref rhs } => {
                 self.emit_has_attr(lhs, rhs);
@@ -815,8 +776,8 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
 
     fn emit_attrset(
         &mut self,
-        stcs: &fix_ir::HashMap<'_, StringId, (RawIrRef<'_>, TextRange)>,
+        stcs: &fix_ir::HashMap<'_, StringId, (MaybeThunk, TextRange)>,
-        dyns: &[(RawIrRef<'_>, RawIrRef<'_>, TextRange)],
+        dyns: &[(RawIrRef<'_>, MaybeThunk, TextRange)],
     ) {
         if stcs.is_empty() && dyns.is_empty() {
             self.emit_op(Op::MakeEmptyAttrs);
@@ -830,19 +791,18 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
         for (&sym, &(val, span)) in stcs.iter() {
             self.emit_u8(AttrKeyType::Static as u8);
             self.emit_str_id(sym);
-            let val_operand = self.classify_value(val);
+            self.emit_maybe_thunk(val);
-            self.emit_inline_operand(val_operand);
             let span_id = self.ctx.register_span(span);
             self.emit_u32(span_id);
         }
-        for &(key, val, span) in dyns.iter() {
+        for &(_key, _val, _span) in dyns.iter() {
-            self.emit_u8(AttrKeyType::Dynamic as u8);
+            todo!("redesign dynamic attr key");
-            let key_operand = self.classify_value(key);
+            // self.emit_u8(AttrKeyType::Dynamic as u8);
-            self.emit_inline_operand(key_operand);
+            // self.emit_maybe_thunk(key);
-            let val_operand = self.classify_value(val);
+            // let val_operand = self.inline_maybe_thunk(val);
-            self.emit_inline_operand(val_operand);
+            // self.emit_maybe_thunk(val);
-            let span_id = self.ctx.register_span(span);
+            // let span_id = self.ctx.register_span(span);
-            self.emit_u32(span_id);
+            // self.emit_u32(span_id);
         }
     }
 
@@ -908,12 +868,12 @@ impl<'a, Ctx: BytecodeContext> BytecodeEmitter<'a, Ctx> {
 
     fn emit_with(
         &mut self,
-        namespace: RawIrRef<'_>,
+        namespace: MaybeThunk,
         body: RawIrRef<'_>,
         thunks: &[(ThunkId, RawIrRef<'_>)],
     ) {
-        self.emit_expr(namespace);
         self.emit_op(Op::PushWith);
+        self.emit_maybe_thunk(namespace);
         self.emit_scope_thunks(thunks);
         self.emit_expr(body);
         self.emit_op(Op::PopWith);

fix-ir/src/downgrade.rs

@@ -1,4 +1,3 @@
-use bumpalo::boxed::Box;
 use bumpalo::collections::{CollectIn, Vec};
 use fix_builtins::BuiltinId;
 use fix_common::Symbol;
@@ -6,7 +5,7 @@ use fix_error::{Error, Result, Source};
 use hashbrown::HashSet;
 use hashbrown::hash_map::Entry;
 use rnix::TextRange;
-use rnix::ast::{self, Expr, HasEntry};
+use rnix::ast::{self, AstToken, Expr, HasEntry};
 use rowan::ast::AstNode;
 
 use super::*;
@@ -39,20 +38,13 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, T, E: std::fmt::Display>
     }
 }
 
-trait BoxIn: Sized {
-    fn box_in(self, bump: &bumpalo::Bump) -> Box<'_, Self> {
-        Box::new_in(self, bump)
-    }
-}
-impl<T: Sized> BoxIn for T {}
-
 pub trait DowngradeContext<'id: 'ir, 'ir> {
     fn new_expr(&self, expr: Ir<'ir, IrRef<'id, 'ir>>) -> IrRef<'id, 'ir>;
-    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> IrRef<'id, 'ir>;
+    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> MaybeThunk;
 
-    fn new_sym(&mut self, sym: String) -> StringId;
+    fn intern_string(&mut self, sym: impl AsRef<str>) -> StringId;
-    fn get_sym(&self, id: StringId) -> Symbol<'_>;
+    fn resolve_sym(&self, id: StringId) -> Symbol<'_>;
-    fn lookup(&self, sym: StringId, span: TextRange) -> Result<IrRef<'id, 'ir>>;
+    fn lookup(&self, sym: StringId, span: TextRange) -> Result<MaybeThunk>;
 
     fn get_current_source(&self) -> Source;
 
@@ -165,14 +157,15 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
         let path = {
             let temp = self.content().require(ctx, span)?;
             let text = temp.text();
-            ctx.new_expr(Ir::Str(
+            let id = ctx.intern_string(&text[1..text.len() - 1]);
-                text[1..text.len() - 1].to_string().box_in(ctx.bump()),
+            let expr = ctx.new_expr(Ir::Str(id));
-            ))
+            ctx.maybe_thunk(expr)
         };
         // HACK: disgusting eww
         let find_file = ctx.new_expr(Ir::Builtin(BuiltinId::FindFile));
-        let sym = ctx.new_sym("nixPath".into());
+        let sym = ctx.intern_string("nixPath");
         let nix_path = ctx.new_expr(Ir::BuiltinConst(sym));
+        let nix_path = ctx.maybe_thunk(nix_path);
         let call = ctx.new_expr(Ir::Call {
             func: find_file,
             arg: nix_path,
@@ -194,14 +187,14 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 
         let bump = ctx.bump();
         let mut parts = normalized.into_iter().map(|part| match part {
-            ast::InterpolPart::Literal(lit) => Ok(ctx.new_expr(Ir::Str(lit.box_in(bump)))),
+            ast::InterpolPart::Literal(lit) => {
-            ast::InterpolPart::Interpolation(interpol) => {
+                let id = ctx.intern_string(lit);
-                let inner = interpol
+                Ok(ctx.new_expr(Ir::Str(id)))
+            }
+            ast::InterpolPart::Interpolation(interpol) => interpol
                 .expr()
                 .require(ctx, interpol.syntax().text_range())?
-                    .downgrade(ctx)?;
+                .downgrade(ctx),
-                Ok(ctx.maybe_thunk(inner))
-            }
         });
 
         Ok(if is_single_literal {
@@ -219,11 +212,15 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> for ast::Literal {
     fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
-        Ok(ctx.new_expr(match self.kind() {
+        let expr = match self.kind() {
             ast::LiteralKind::Integer(int) => Ir::Int(int.value().require(ctx, span)?),
             ast::LiteralKind::Float(float) => Ir::Float(float.value().require(ctx, span)?),
-            ast::LiteralKind::Uri(uri) => Ir::Str(uri.to_string().box_in(ctx.bump())),
+            ast::LiteralKind::Uri(uri) => {
-        }))
+                let id = ctx.intern_string(uri.syntax().text());
+                Ir::Str(id)
+            }
+        };
+        Ok(ctx.new_expr(expr))
     }
 }
 
@@ -231,8 +228,8 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
     fn downgrade(self, ctx: &mut Ctx) -> Result<IrRef<'id, 'ir>> {
         let span = self.syntax().text_range();
         let text = self.ident_token().require(ctx, span)?.to_string();
-        let sym = ctx.new_sym(text);
+        let sym = ctx.intern_string(text);
-        ctx.lookup(sym, span)
+        ctx.lookup(sym, span).map(|thunk| thunk.to_ir(ctx))
     }
 }
 
@@ -299,12 +296,10 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
         let span = self.syntax().text_range();
         let expr = self.expr().require(ctx, span)?.downgrade(ctx)?;
         let attrpath = downgrade_attrpath(self.attrpath().require(ctx, span)?, ctx)?;
-        let default = if let Some(default) = self.default_expr() {
+        let default = self
-            let default_expr = default.downgrade(ctx)?;
+            .default_expr()
-            Some(ctx.maybe_thunk(default_expr))
+            .map(|expr| expr.downgrade(ctx))
-        } else {
+            .transpose()?;
-            None
-        };
         let span = self.syntax().text_range();
         Ok(ctx.new_expr(Ir::Select {
             expr,
@@ -331,7 +326,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
             Ok(ctx.new_expr(Ir::AttrSet { stcs, dyns }))
         })?;
 
-        let body_sym = ctx.new_sym("body".to_string());
+        let body_sym = ctx.intern_string("body");
         Ok(ctx.new_expr(Ir::Select {
             expr: attrset_expr,
             attrpath: Vec::from_iter_in(
@@ -390,7 +385,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
 
             match raw_param {
                 ast::Param::IdentParam(id) => {
-                    let param_sym = ctx.new_sym(id.to_string());
+                    let param_sym = ctx.intern_string(id.to_string());
                     param = None;
 
                     body = ctx.with_param_scope(param_sym, |ctx| body_ast.downgrade(ctx))?;
@@ -400,7 +395,7 @@ impl<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>> Downgrade<'id, 'ir, Ctx> fo
                         .pat_bind()
                         .map(|alias| {
                             let ident = alias.ident().require(ctx, alias.syntax().text_range())?;
-                            Ok::<_, std::boxed::Box<Error>>(ctx.new_sym(ident.to_string()))
+                            Ok::<_, std::boxed::Box<Error>>(ctx.intern_string(ident.to_string()))
                         })
                         .transpose()?;
 
@@ -484,7 +479,7 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
 
         match first {
             ast::Attr::Ident(ident) => {
-                let sym = ctx.new_sym(ident.to_string());
+                let sym = ctx.intern_string(ident.to_string());
                 self.insert_static(sym, span, rest, value, ctx)
             }
             ast::Attr::Str(string) => {
@@ -493,7 +488,7 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
                     && let ast::InterpolPart::Literal(lit) =
                         parts.into_iter().next().expect("len checked")
                 {
-                    let sym = ctx.new_sym(lit);
+                    let sym = ctx.intern_string(lit);
                     return self.insert_static(sym, span, rest, value, ctx);
                 }
                 self.insert_dynamic(first.clone(), span, rest, value, ctx)
@@ -736,14 +731,14 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
         for attr in inherit.attrs() {
             let span = attr.syntax().text_range();
             let sym = match &attr {
-                ast::Attr::Ident(ident) => ctx.new_sym(ident.to_string()),
+                ast::Attr::Ident(ident) => ctx.intern_string(ident.to_string()),
                 ast::Attr::Str(s) => {
                     let parts = s.normalized_parts();
                     if parts.len() == 1
                         && let ast::InterpolPart::Literal(lit) =
                             parts.into_iter().next().expect("len checked")
                     {
-                        ctx.new_sym(lit)
+                        ctx.intern_string(lit)
                     } else {
                         return Err(Error::downgrade_error(
                             "dynamic attributes not allowed in inherit".to_string(),
@@ -763,7 +758,7 @@ impl<'id: 'ir, 'ir> PendingAttrSet<'ir> {
 
             if self.stcs.contains_key(&sym) {
                 return Err(Error::downgrade_error(
-                    format!("attribute '{}' already defined", ctx.get_sym(sym)),
+                    format!("attribute '{}' already defined", ctx.resolve_sym(sym)),
                     ctx.get_current_source(),
                     span,
                 ));
@@ -840,8 +835,8 @@ fn make_attrpath_value_entry<'ir>(path: Vec<'ir, ast::Attr>, value: ast::Expr) -
 }
 
 struct FinalizedAttrSet<'id, 'ir> {
-    stcs: HashMap<'ir, StringId, (IrRef<'id, 'ir>, TextRange)>,
+    stcs: HashMap<'ir, StringId, (MaybeThunk, TextRange)>,
-    dyns: Vec<'ir, (IrRef<'id, 'ir>, IrRef<'id, 'ir>, TextRange)>,
+    dyns: Vec<'ir, (IrRef<'id, 'ir>, MaybeThunk, TextRange)>,
 }
 
 fn downgrade_attrs<'id, 'ir>(
@@ -861,17 +856,17 @@ fn downgrade_attr<'id, 'ir>(
     use ast::InterpolPart::*;
     match attr {
         Ident(ident) => Ok(Attr::Str(
-            ctx.new_sym(ident.to_string()),
+            ctx.intern_string(ident.to_string()),
             ident.syntax().text_range(),
         )),
         Str(string) => {
             let parts = string.normalized_parts();
             let span = string.syntax().text_range();
             if parts.is_empty() {
-                Ok(Attr::Str(ctx.new_sym("".to_string()), span))
+                Ok(Attr::Str(ctx.intern_string(""), span))
             } else if parts.len() == 1 {
                 match parts.into_iter().next().expect("len checked") {
-                    Literal(ident) => Ok(Attr::Str(ctx.new_sym(ident), span)),
+                    Literal(ident) => Ok(Attr::Str(ctx.intern_string(ident), span)),
                     Interpolation(interpol) => Ok(Attr::Dynamic(
                         interpol
                             .expr()
@@ -885,7 +880,10 @@ fn downgrade_attr<'id, 'ir>(
                 let parts = parts
                     .into_iter()
                     .map(|part| match part {
-                        Literal(lit) => Ok(ctx.new_expr(Ir::Str(lit.box_in(bump)))),
+                        Literal(lit) => {
+                            let id = ctx.intern_string(lit);
+                            Ok(ctx.new_expr(Ir::Str(id)))
+                        }
                         Interpolation(interpol) => interpol
                             .expr()
                             .require(ctx, interpol.syntax().text_range())?
@@ -950,13 +948,13 @@ where
     for entry in pat_entries {
         let ident = entry.ident().require(ctx, entry.syntax().text_range())?;
         let sym_span = ident.syntax().text_range();
-        let sym = ctx.new_sym(ident.syntax().text().to_string());
+        let sym = ctx.intern_string(ident.syntax().text().to_string());
         let default = entry.default();
         let span = entry.syntax().text_range();
 
         if !seen_params.insert(sym) {
             return Err(Error::downgrade_error(
-                format!("duplicate parameter '{}'", ctx.get_sym(sym)),
+                format!("duplicate parameter '{}'", ctx.resolve_sym(sym)),
                 ctx.get_current_source(),
                 span,
             ));
@@ -1001,12 +999,13 @@ where
                     default,
                     span,
                 } = param;
-                let default = if let Some(default) = default {
+                let default = default.map(|default| default.downgrade(ctx)).transpose()?;
-                    let default = default.clone().downgrade(ctx)?;
+                // let default = if let Some(default) = default {
-                    Some(ctx.maybe_thunk(default))
+                //     let default = default.clone().downgrade(ctx)?;
-                } else {
+                //     Some(ctx.maybe_thunk(default))
-                    None
+                // } else {
-                };
+                //     None
+                // };
 
                 Ok(ctx.new_expr(Ir::Select {
                     expr: arg,
@@ -1075,7 +1074,7 @@ where
     F: FnOnce(
         &mut Ctx,
         &[StringId],
-        &[(IrRef<'id, 'ir>, IrRef<'id, 'ir>, TextRange)],
+        &[(IrRef<'id, 'ir>, MaybeThunk, TextRange)],
     ) -> Result<IrRef<'id, 'ir>>,
 {
     let mut pending = PendingAttrSet::new_in(ctx.bump());
@@ -1088,18 +1087,21 @@ where
 
     ctx.with_let_scope(&keys, |ctx| {
         let finalized = finalize_pending_set::<_, ALLOW_DYN>(pending, &inherit_lookups, ctx)?;
-        let vals = keys
+        let vals = {
-            .iter()
+            let mut temp = Vec::with_capacity_in(keys.len(), ctx.bump());
-            .map(|sym| finalized.stcs.get(sym).expect("WTF").0)
+            for sym in &keys {
-            .collect_in(ctx.bump());
+                temp.push(finalized.stcs.get(sym).expect("WTF").0.to_ir(ctx));
+            }
+            temp
+        };
         body_fn(ctx, &keys, &finalized.dyns).map(|body| (vals, body))
     })
 }
 
-fn collect_inherit_lookups<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>>(
+fn collect_inherit_lookups<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>>(
     entries: &[ast::Entry],
     ctx: &mut Ctx,
-) -> Result<HashMap<'ir, StringId, (IrRef<'id, 'ir>, TextRange)>> {
+) -> Result<HashMap<'ir, StringId, (MaybeThunk, TextRange)>> {
     let mut inherit_lookups = HashMap::new_in(ctx.bump());
     for entry in entries {
         if let ast::Entry::Inherit(inherit) = entry
@@ -1108,7 +1110,7 @@ fn collect_inherit_lookups<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>>(
             for attr in inherit.attrs() {
                 if let ast::Attr::Ident(ident) = attr {
                     let attr_span = ident.syntax().text_range();
-                    let sym = ctx.new_sym(ident.to_string());
+                    let sym = ctx.intern_string(ident.to_string());
                     let expr = ctx.lookup(sym, attr_span)?;
                     inherit_lookups.insert(sym, (expr, attr_span));
                 }
@@ -1127,7 +1129,7 @@ fn collect_binding_syms<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, const AL
     for (sym, (_, span)) in &pending.stcs {
         if !binding_syms.insert(*sym) {
             return Err(Error::downgrade_error(
-                format!("attribute '{}' already defined", ctx.get_sym(*sym)),
+                format!("attribute '{}' already defined", ctx.resolve_sym(*sym)),
                 ctx.get_current_source(),
                 *span,
             ));
@@ -1139,15 +1141,15 @@ fn collect_binding_syms<'id: 'ir, 'ir, Ctx: DowngradeContext<'id, 'ir>, const AL
 
 fn finalize_pending_set<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_DYN: bool>(
     pending: PendingAttrSet,
-    inherit_lookups: &HashMap<StringId, (IrRef<'id, 'ir>, TextRange)>,
+    inherit_lookups: &HashMap<StringId, (MaybeThunk, TextRange)>,
     ctx: &mut Ctx,
 ) -> Result<FinalizedAttrSet<'id, 'ir>> {
     let mut stcs = HashMap::new_in(ctx.bump());
     let mut dyns = Vec::new_in(ctx.bump());
 
     for (sym, (value, value_span)) in pending.stcs {
-        let expr_id = finalize_pending_value::<_, ALLOW_DYN>(value, inherit_lookups, ctx)?;
+        let expr = finalize_pending_value::<_, ALLOW_DYN>(value, inherit_lookups, ctx)?;
-        stcs.insert(sym, (expr_id, value_span));
+        stcs.insert(sym, (ctx.maybe_thunk(expr), value_span));
     }
 
     if ALLOW_DYN {
@@ -1155,12 +1157,10 @@ fn finalize_pending_set<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_D
             let key_id = downgrade_attr(attr, ctx)?;
             let key_expr = match key_id {
                 Attr::Dynamic(id, _) => id,
-                Attr::Str(sym, _attr_span) => {
+                Attr::Str(sym, _attr_span) => ctx.new_expr(Ir::Str(sym)),
-                    ctx.new_expr(Ir::Str(ctx.get_sym(sym).to_string().box_in(ctx.bump())))
-                }
             };
-            let value_id = finalize_pending_value::<_, ALLOW_DYN>(value, inherit_lookups, ctx)?;
+            let value = finalize_pending_value::<_, ALLOW_DYN>(value, inherit_lookups, ctx)?;
-            dyns.push((key_expr, value_id, value_span));
+            dyns.push((key_expr, ctx.maybe_thunk(value), value_span));
         }
     }
 
@@ -1169,30 +1169,25 @@ fn finalize_pending_set<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_D
 
 fn finalize_pending_value<'id, 'ir, Ctx: DowngradeContext<'id, 'ir>, const ALLOW_DYN: bool>(
     value: PendingValue,
-    inherit_lookups: &HashMap<StringId, (IrRef<'id, 'ir>, TextRange)>,
+    inherit_lookups: &HashMap<StringId, (MaybeThunk, TextRange)>,
     ctx: &mut Ctx,
 ) -> Result<IrRef<'id, 'ir>> {
     match value {
-        PendingValue::Expr(expr) => {
+        PendingValue::Expr(expr) => expr.downgrade(ctx),
-            let id = Downgrade::downgrade(expr, ctx)?;
-            Ok(ctx.maybe_thunk(id))
-        }
         PendingValue::InheritFrom(from_expr, sym, span) => {
-            let from_id = Downgrade::downgrade(from_expr, ctx)?;
+            let from = Downgrade::downgrade(from_expr, ctx)?;
-            let select_id = ctx.new_expr(Ir::Select {
+            Ok(ctx.new_expr(Ir::Select {
-                expr: from_id,
+                expr: from,
                 attrpath: Vec::from_iter_in([Attr::Str(sym, span)], ctx.bump()),
                 default: None,
                 span,
-            });
+            }))
-            Ok(ctx.maybe_thunk(select_id))
         }
         PendingValue::InheritScope(sym, span) => {
             if let Some(&(expr, _)) = inherit_lookups.get(&sym) {
-                Ok(ctx.maybe_thunk(expr))
+                Ok(expr.to_ir(ctx))
             } else {
-                let lookup_id = ctx.lookup(sym, span)?;
+                ctx.lookup(sym, span).map(|val| val.to_ir(ctx))
-                Ok(ctx.maybe_thunk(lookup_id))
             }
         }
         PendingValue::Set(set) => {
@@ -1221,7 +1216,8 @@ fn downgrade_path<'id, 'ir>(
         .into_iter()
         .map(|part| match part {
             ast::InterpolPart::Literal(lit) => {
-                Ok(ctx.new_expr(Ir::Str(lit.text().to_string().box_in(ctx.bump()))))
+                let id = ctx.intern_string(lit.text());
+                Ok(ctx.new_expr(Ir::Str(id)))
             }
             ast::InterpolPart::Interpolation(interpol) => interpol
                 .expr()

fix-ir/src/lib.rs

@@ -2,7 +2,6 @@ use std::hash::Hash;
 use std::ops::Deref;
 
 use bumpalo::Bump;
-use bumpalo::boxed::Box;
 use bumpalo::collections::Vec;
 use fix_builtins::{BUILTINS, BuiltinId};
 use fix_common::StringId;
@@ -11,6 +10,8 @@ use num_enum::TryFromPrimitive as _;
 use rnix::{TextRange, ast};
 use string_interner::DefaultStringInterner;
 
+use crate::downgrade::DowngradeContext;
+
 pub mod downgrade;
 
 pub type HashMap<'ir, K, V> = hashbrown::HashMap<K, V, hashbrown::DefaultHashBuilder, &'ir Bump>;
@@ -62,6 +63,46 @@ impl<'ir> Deref for RawIrRef<'ir> {
     }
 }
 
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+pub enum MaybeThunk {
+    Int(i64),
+    Float(f64),
+    Bool(bool),
+    Null,
+    Str(StringId),
+    Path(StringId),
+    Thunk(ThunkId),
+    Arg { layer: usize },
+    Builtin(BuiltinId),
+    Builtins,
+    ReplBinding(StringId),
+    ScopedImportBinding(StringId),
+    WithLookup(StringId),
+}
+
+impl MaybeThunk {
+    fn to_ir<'id, 'ir>(self, ctx: &mut impl DowngradeContext<'id, 'ir>) -> IrRef<'id, 'ir> {
+        use MaybeThunk::*;
+        let ir = match self {
+            Int(x) => Ir::Int(x),
+            Float(x) => Ir::Float(x),
+            Bool(x) => Ir::Bool(x),
+            Null => Ir::Null,
+            Str(x) => Ir::Str(x),
+            Path(x) => Ir::Path(ctx.new_expr(Ir::Str(x))),
+            Thunk(x) => Ir::Thunk(x),
+            Arg { layer } => Ir::Arg { layer },
+            Builtin(x) => Ir::Builtin(x),
+            Builtins => Ir::Builtins,
+            ReplBinding(x) => Ir::ReplBinding(x),
+            ScopedImportBinding(x) => Ir::ScopedImportBinding(x),
+            WithLookup(x) => Ir::WithLookup(x),
+        };
+        ctx.new_expr(ir)
+    }
+}
+
 #[repr(C)]
 #[derive(Debug)]
 pub enum Ir<'ir, Ref> {
@@ -69,15 +110,15 @@ pub enum Ir<'ir, Ref> {
     Float(f64),
     Bool(bool),
     Null,
-    Str(Box<'ir, String>),
+    Str(StringId),
+    Path(Ref),
     AttrSet {
-        stcs: HashMap<'ir, StringId, (Ref, TextRange)>,
+        stcs: HashMap<'ir, StringId, (MaybeThunk, TextRange)>,
-        dyns: Vec<'ir, (Ref, Ref, TextRange)>,
+        dyns: Vec<'ir, (Ref, MaybeThunk, TextRange)>,
     },
     List {
-        items: Vec<'ir, Ref>,
+        items: Vec<'ir, MaybeThunk>,
     },
-    Path(Ref),
     ConcatStrings {
         parts: Vec<'ir, Ref>,
         force_string: bool,
@@ -118,7 +159,7 @@ pub enum Ir<'ir, Ref> {
     },
 
     With {
-        namespace: Ref,
+        namespace: MaybeThunk,
         body: Ref,
         thunks: Vec<'ir, (ThunkId, Ref)>,
     },
@@ -135,7 +176,7 @@ pub enum Ir<'ir, Ref> {
     },
     Call {
         func: Ref,
-        arg: Ref,
+        arg: MaybeThunk,
         span: TextRange,
     },
 

fix-vm/src/boxing.rs

@@ -24,7 +24,7 @@ impl<T: Default + Copy, const N: usize> ArrayExt<N> for [T; N] {
     }
 }
 
-pub trait RawStore: Sized {
+pub(crate) trait RawStore: Sized {
     fn to_val(self, value: &mut Value);
     fn from_val(value: &Value) -> Self;
 }

fix-vm/src/stack.rs

@@ -1,76 +0,0 @@
-use std::mem::MaybeUninit;
-
-use gc_arena::Collect;
-
-pub(super) struct Stack<const N: usize, T> {
-    inner: Box<[MaybeUninit<T>; N]>,
-    len: usize,
-}
-
-unsafe impl<'gc, const N: usize, T: Collect<'gc> + 'gc> Collect<'gc> for Stack<N, T> {
-    const NEEDS_TRACE: bool = T::NEEDS_TRACE;
-    fn trace<U: gc_arena::collect::Trace<'gc>>(&self, cc: &mut U) {
-        for item in self.inner[..self.len].iter() {
-            unsafe {
-                item.assume_init_ref().trace(cc);
-            }
-        }
-    }
-}
-
-impl<const N: usize, T> Default for Stack<N, T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<const N: usize, T> Stack<N, T> {
-    pub(super) fn new() -> Self {
-        Self {
-            inner: Box::new([const { MaybeUninit::uninit() }; N]),
-            len: 0,
-        }
-    }
-
-    pub(super) fn push(&mut self, val: T) -> Result<(), T> {
-        if self.len == N {
-            return Err(val);
-        }
-        unsafe {
-            self.inner.get_unchecked_mut(self.len).write(val);
-        }
-        self.len += 1;
-        Ok(())
-    }
-
-    pub(super) fn pop(&mut self) -> Option<T> {
-        if self.len == 0 {
-            return None;
-        }
-        let ret = unsafe {
-            self.inner
-                .get_unchecked_mut(self.len - 1)
-                .assume_init_read()
-        };
-        self.len -= 1;
-        Some(ret)
-    }
-
-    pub(super) fn tos(&self) -> Option<&T> {
-        if self.len == 0 {
-            return None;
-        }
-        Some(unsafe { self.inner.get_unchecked(self.len - 1).assume_init_ref() })
-    }
-
-    pub(super) fn tos_mut(&mut self) -> Option<&mut T> {
-        if self.len == 0 {
-            return None;
-        }
-        Some(unsafe { self.inner.get_unchecked_mut(self.len - 1).assume_init_mut() })
-    }
-
-    pub(super) fn len(&self) -> usize {
-        self.len
-    }
-}

fix-vm/src/value.rs

@@ -22,13 +22,14 @@ mod private {
 }
 
 /// # Safety
+///
 /// 1. TAG must be unique among all implementors.
 /// 2. TAG must be within 1..=7
-pub(crate) unsafe trait Storable: private::Cealed {
+pub unsafe trait Storable: private::Cealed {
     const TAG: (bool, u8);
 }
-pub(crate) trait InlineStorable: Storable + RawStore {}
+pub trait InlineStorable: Storable + RawStore {}
-pub(crate) trait GcStorable: Storable {}
+pub trait GcStorable: Storable {}
 
 macro_rules! define_value_types {
     (
@@ -263,11 +264,11 @@ impl<'gc> Value<'gc> {
     }
 
     #[inline]
-    pub(crate) fn restrict(self) -> Option<StrictValue<'gc>> {
+    pub(crate) fn restrict(self) -> Result<StrictValue<'gc>, Gc<'gc, Thunk<'gc>>> {
-        if !self.is::<Thunk<'gc>>() {
+        if let Some(thunk) = self.as_gc::<Thunk<'gc>>() {
-            Some(StrictValue(self))
+            Err(thunk)
         } else {
-            None
+            Ok(StrictValue(self))
         }
     }
 }
@@ -384,9 +385,7 @@ impl<'gc> Deref for AttrSet<'gc> {
 }
 
 impl<'gc> AttrSet<'gc> {
-    pub(crate) fn from_sorted_unchecked(
+    pub(crate) fn from_sorted_unchecked(entries: SmallVec<[(StringId, Value<'gc>); 4]>) -> Self {
-        entries: SmallVec<[(StringId, Value<'gc>); 4]>,
-    ) -> Self {
         debug_assert!(entries.is_sorted_by_key(|(key, _)| *key));
         Self { entries }
     }
@@ -464,7 +463,7 @@ pub(crate) enum ThunkState<'gc> {
         arg: Value<'gc>,
     },
     Blackhole,
-    Evaluated(Value<'gc>),
+    Evaluated(StrictValue<'gc>),
 }
 
 #[derive(Collect, Debug)]

fix/Cargo.toml

@@ -23,7 +23,6 @@ miette = { version = "7.4", features = ["fancy"] }
 
 # Data Structure
 hashbrown = { workspace = true }
-smallvec = { workspace = true }
 string-interner = { workspace = true }
 
 # Memory Management

fix/src/lib.rs

@@ -2,15 +2,16 @@
 #![allow(dead_code)]
 
 use bumpalo::Bump;
+use fix_codegen::disassembler::{Disassembler, DisassemblerContext};
 use fix_codegen::{BytecodeContext, InstructionPtr};
 use fix_common::{StringId, Symbol};
 use fix_error::{Error, Result, Source};
 use fix_ir::downgrade::{Downgrade as _, DowngradeContext};
-use fix_ir::{Ir, IrRef, RawIrRef, ThunkId};
+use fix_ir::{Ir, IrRef, MaybeThunk, RawIrRef, ThunkId};
 use fix_vm::{ForceMode, StaticValue, Vm, VmContext};
 use ghost_cell::{GhostCell, GhostToken};
 use hashbrown::{HashMap, HashSet};
-use string_interner::DefaultStringInterner;
+use string_interner::{DefaultStringInterner, Symbol as _};
 
 // mod fetcher;
 // mod nar;
@@ -105,6 +106,10 @@ impl Evaluator {
         Ok(ip)
     }
 
+    pub fn disassemble_colored(&self, ip: InstructionPtr) -> String {
+        Disassembler::new(ip, self).disassemble_colored()
+    }
+
     fn downgrade_ctx<'a, 'bump, 'id>(
         &'a mut self,
         bump: &'bump Bump,
@@ -289,56 +294,66 @@ impl<'ctx: 'ir, 'id, 'ir> DowngradeContext<'id, 'ir> for DowngradeCtx<'ctx, 'id,
         IrRef::new(self.bump.alloc(GhostCell::new(expr)))
     }
 
-    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> IrRef<'id, 'ir> {
+    fn maybe_thunk(&mut self, ir: IrRef<'id, 'ir>) -> MaybeThunk {
-        if !should_thunk(ir, &self.token) {
+        use MaybeThunk::*;
-            return ir;
+        match *ir.borrow(&self.token) {
+            Ir::Builtin(x) => return Builtin(x),
+            Ir::Int(x) => return Int(x),
+            Ir::Float(x) => return Float(x),
+            Ir::Bool(x) => return Bool(x),
+            Ir::Str(x) => return Str(x),
+            Ir::Thunk(x) => return Thunk(x),
+            Ir::Arg { layer } => return Arg { layer },
+            Ir::Builtins => return Builtins,
+            Ir::Null => return Null,
+            _ => (),
         }
-
         let id = ThunkId(*self.thunk_count);
         *self.thunk_count = self.thunk_count.checked_add(1).expect("thunk id overflow");
         self.thunk_scopes
             .last_mut()
             .expect("no active cache scope")
             .add_binding(id, ir, &self.token);
-        IrRef::alloc(self.bump, Ir::Thunk(id))
+        Thunk(id)
     }
 
-    fn new_sym(&mut self, sym: String) -> StringId {
+    fn intern_string(&mut self, sym: impl AsRef<str>) -> StringId {
         StringId(self.strings.get_or_intern(sym))
     }
 
-    fn get_sym(&self, id: StringId) -> Symbol<'_> {
+    fn resolve_sym(&self, id: StringId) -> Symbol<'_> {
         self.strings.resolve(id.0).expect("no symbol found").into()
     }
 
-    fn lookup(&self, sym: StringId, span: rnix::TextRange) -> Result<IrRef<'id, 'ir>> {
+    fn lookup(&self, sym: StringId, span: rnix::TextRange) -> Result<MaybeThunk> {
         for scope in self.scopes.iter().rev() {
             match scope {
                 &Scope::Global(global_scope) => {
+                    use MaybeThunk::*;
                     if let Some(expr) = global_scope.get(&sym) {
-                        let ir = match expr {
+                        let val = match expr {
-                            Ir::Builtins => Ir::Builtins,
+                            Ir::Builtins => Builtins,
-                            Ir::Builtin(s) => Ir::Builtin(*s),
+                            Ir::Builtin(s) => Builtin(*s),
-                            Ir::Bool(b) => Ir::Bool(*b),
+                            Ir::Bool(b) => Bool(*b),
-                            Ir::Null => Ir::Null,
+                            Ir::Null => Null,
                             _ => unreachable!("globals should only contain leaf IR nodes"),
                         };
-                        return Ok(self.new_expr(ir));
+                        return Ok(val);
                     }
                 }
                 &Scope::Repl(repl_bindings) => {
                     if repl_bindings.contains(&sym) {
-                        return Ok(self.new_expr(Ir::ReplBinding(sym)));
+                        return Ok(MaybeThunk::ReplBinding(sym));
                     }
                 }
                 Scope::ScopedImport(scoped_bindings) => {
                     if scoped_bindings.contains(&sym) {
-                        return Ok(self.new_expr(Ir::ScopedImportBinding(sym)));
+                        return Ok(MaybeThunk::ScopedImportBinding(sym));
                     }
                 }
                 Scope::Let(let_scope) => {
                     if let Some(&expr) = let_scope.get(&sym) {
-                        return Ok(self.new_expr(Ir::Thunk(expr)));
+                        return Ok(MaybeThunk::Thunk(expr));
                     }
                 }
                 &Scope::Param {
@@ -346,19 +361,19 @@ impl<'ctx: 'ir, 'id, 'ir> DowngradeContext<'id, 'ir> for DowngradeCtx<'ctx, 'id,
                     abs_layer,
                 } => {
                     if param_sym == sym {
-                        return Ok(self.new_expr(Ir::Arg {
+                        return Ok(MaybeThunk::Arg {
                             layer: self.thunk_scopes.len() - abs_layer,
-                        }));
+                        });
                     }
                 }
             }
         }
 
         if self.with_scope_count > 0 {
-            Ok(self.new_expr(Ir::WithLookup(sym)))
+            Ok(MaybeThunk::WithLookup(sym))
         } else {
             Err(Error::downgrade_error(
-                format!("'{}' not found", self.get_sym(sym)),
+                format!("'{}' not found", self.resolve_sym(sym)),
                 self.get_current_source(),
                 span,
             ))
@@ -504,6 +519,9 @@ struct OwnedIr {
 }
 
 impl OwnedIr {
+    /// # Safety
+    ///
+    /// `ir` must be allocated from `bump`.
     unsafe fn new(ir: RawIrRef<'_>, bump: Bump) -> Self {
         Self {
             _bump: bump,
@@ -553,3 +571,15 @@ impl BytecodeContext for Evaluator {
         self.constants.insert(val)
     }
 }
+
+impl DisassemblerContext for Evaluator {
+    fn get_code(&self) -> &[u8] {
+        &self.bytecode
+    }
+
+    #[allow(clippy::unwrap_used)]
+    fn resolve_string(&self, id: u32) -> &str {
+        let id = string_interner::symbol::SymbolU32::try_from_usize(id as usize).unwrap();
+        self.strings.resolve(id).unwrap()
+    }
+}

fix/src/main.rs

@@ -40,7 +40,7 @@ struct ExprSource {
     file: Option<PathBuf>,
 }
 
-fn run_compile(eval: &mut Evaluator, src: ExprSource, _silent: bool) -> Result<()> {
+fn run_compile(eval: &mut Evaluator, src: ExprSource, silent: bool) -> Result<()> {
     let src = if let Some(expr) = src.expr {
         Source::new_eval(expr)?
     } else if let Some(file) = src.file {
@@ -49,10 +49,10 @@ fn run_compile(eval: &mut Evaluator, src: ExprSource, _silent: bool) -> Result<(
         unreachable!()
     };
     match eval.compile_bytecode(src) {
-        Ok(_ip) => {
+        Ok(ip) => {
-            // if !silent {
+            if !silent {
-            //     println!("{}", eval.disassemble_colored(ip));
+                println!("{}", eval.disassemble_colored(ip));
-            // }
+            }
         }
         Err(err) => {
             eprintln!("{:?}", miette::Report::new(*err));

flake.lock

@@ -8,11 +8,11 @@
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
-        "lastModified": 1774596377,
+        "lastModified": 1775807984,
-        "narHash": "sha256-DiSLMxyTwIUAlhOe34r6kKNQRv6PTF+vf0MG45mAyn4=",
+        "narHash": "sha256-Redoe3D9zGN5I9QPHWL9vfMVQBehY1fKsMiRXQ83X3w=",
         "owner": "nix-community",
         "repo": "fenix",
-        "rev": "a88a1c8cf2f094da6347fcec54089f4bcb518409",
+        "rev": "fcf90c0c4d368b2ca917a7afa6d08e98a397e5fd",
         "type": "github"
       },
       "original": {
@@ -37,11 +37,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1774386573,
+        "lastModified": 1775710090,
-        "narHash": "sha256-4hAV26quOxdC6iyG7kYaZcM3VOskcPUrdCQd/nx8obc=",
+        "narHash": "sha256-ar3rofg+awPB8QXDaFJhJ2jJhu+KqN/PRCXeyuXR76E=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "46db2e09e1d3f113a13c0d7b81e2f221c63b8ce9",
+        "rev": "4c1018dae018162ec878d42fec712642d214fdfa",
         "type": "github"
       },
       "original": {
@@ -61,11 +61,11 @@
     "rust-analyzer-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1774569884,
+        "lastModified": 1775745684,
-        "narHash": "sha256-E8iWEPzg7OnE0XXXjo75CX7xFauqzJuGZ5wSO9KS8Ek=",
+        "narHash": "sha256-8MbfLwd60FNa8dRFkjE+G3TT/x21G3Rsplm1bMBQUtU=",
         "owner": "rust-lang",
         "repo": "rust-analyzer",
-        "rev": "443ddcddd0c73b07b799d052f5ef3b448c2f3508",
+        "rev": "64ddb549bc9a70d011328746fa46a8883f937b6b",
         "type": "github"
       },
       "original": {

flake.nix

@@ -26,23 +26,16 @@
                 "rustfmt"
                 "rust-analyzer"
               ])
-              cargo-outdated
               cargo-machete
+              cargo-bloat
               lldb
               valgrind
               hyperfine
               just
               samply
-              jq
               tokei
 
-              nodejs
-              nodePackages.npm
-              biome
-
               claude-code
-              codex
-              opencode
             ];
           };
         }