diff options
| -rw-r--r-- | tvix/eval/src/compiler/mod.rs | 27 | ||||
| -rw-r--r-- | tvix/eval/src/compiler/scope.rs | 62 |
2 files changed, 33 insertions, 56 deletions
diff --git a/tvix/eval/src/compiler/mod.rs b/tvix/eval/src/compiler/mod.rs index 0d2ed66f5bf5..ca1098af64dd 100644 --- a/tvix/eval/src/compiler/mod.rs +++ b/tvix/eval/src/compiler/mod.rs @@ -29,7 +29,7 @@ use crate::opcode::{CodeIdx, Count, JumpOffset, OpCode, StackIdx, UpvalueIdx}; use crate::value::{Closure, Lambda, Value}; use crate::warnings::{EvalWarning, WarningKind}; -use self::scope::{Depth, Local, LocalPosition, Scope, Upvalue}; +use self::scope::{Local, LocalPosition, Scope, Upvalue}; /// Represents the result of compiling a piece of Nix code. If /// compilation was successful, the resulting bytecode can be passed @@ -752,7 +752,7 @@ impl Compiler { // Calculate the with_idx without taking into account // uninitialised variables that are not yet in their stack // slots. - .filter(|l| matches!(l.depth, Depth::At(_))) + .filter(|l| l.initialised) .count() - 1; @@ -897,9 +897,7 @@ impl Compiler { // TL;DR - iterate from the back while things belonging to the // ended scope still exist. while !self.scope().locals.is_empty() - && self.scope().locals[self.scope().locals.len() - 1] - .depth - .above(self.scope().scope_depth) + && self.scope().locals[self.scope().locals.len() - 1].above(self.scope().scope_depth) { pops += 1; @@ -944,13 +942,8 @@ impl Compiler { } let mut shadowed = false; - for local in self.scope().locals.iter().rev() { - if local.depth.below(self.scope().scope_depth) { - // Shadowing identifiers from higher scopes is allowed. - break; - } - - if local.name == name { + for other in self.scope().locals.iter().rev() { + if other.name == name && other.depth == depth { shadowed = true; break; } @@ -965,7 +958,8 @@ impl Compiler { self.scope_mut().locals.push(Local { name, - depth: Depth::Unitialised, + depth, + initialised: false, node: Some(node), phantom: false, used: false, @@ -978,7 +972,8 @@ impl Compiler { fn declare_phantom(&mut self) { let depth = self.scope().scope_depth; self.scope_mut().locals.push(Local { - depth: Depth::At(depth), + depth, + initialised: true, name: "".into(), node: None, phantom: true, @@ -990,8 +985,8 @@ impl Compiler { fn mark_initialised(&mut self, name: &str) { let depth = self.scope().scope_depth; for local in self.scope_mut().locals.iter_mut().rev() { - if matches!(local.depth, Depth::Unitialised) && local.name == name { - local.depth = Depth::At(depth); + if !local.initialised && local.depth == depth && local.name == name { + local.initialised = true; return; } } diff --git a/tvix/eval/src/compiler/scope.rs b/tvix/eval/src/compiler/scope.rs index 3061e08ead25..a76a411b461b 100644 --- a/tvix/eval/src/compiler/scope.rs +++ b/tvix/eval/src/compiler/scope.rs @@ -16,34 +16,6 @@ use smol_str::SmolStr; use crate::opcode::{StackIdx, UpvalueIdx}; -/// Represents the initialisation status of a variable, tracking -/// whether it is only known or also already defined. -pub enum Depth { - /// Variable is defined and located at the given depth. - At(usize), - - /// Variable is known but not yet defined. - Unitialised, -} - -impl Depth { - /// Does this variable live above the other given depth? - pub fn above(&self, theirs: usize) -> bool { - match self { - Depth::Unitialised => false, - Depth::At(ours) => *ours > theirs, - } - } - - /// Does this variable live below the other given depth? - pub fn below(&self, theirs: usize) -> bool { - match self { - Depth::Unitialised => false, - Depth::At(ours) => *ours < theirs, - } - } -} - /// Represents a single local already known to the compiler. pub struct Local { // Definition name, which can be different kinds of tokens (plain @@ -55,7 +27,10 @@ pub struct Local { pub node: Option<rnix::SyntaxNode>, // Scope depth of this local. - pub depth: Depth, + pub depth: usize, + + // Is this local initialised? + pub initialised: bool, // Phantom locals are not actually accessible by users (e.g. // intermediate values used for `with`). @@ -65,6 +40,13 @@ pub struct Local { pub used: bool, } +impl Local { + /// Does this local live above the other given depth? + pub fn above(&self, theirs: usize) -> bool { + self.depth > theirs + } +} + /// Represents the current position of a local as resolved in a scope. pub enum LocalPosition { /// Local is not known in this scope. @@ -175,17 +157,17 @@ impl Scope { if !local.phantom && local.name == name { local.used = true; - match local.depth { - // This local is still being initialised, meaning - // that we know its final runtime stack position, - // but it is not yet on the stack. - Depth::Unitialised => return LocalPosition::Recursive(StackIdx(idx)), - - // This local is known, but we need to account for - // uninitialised variables in this "initialiser - // stack". - Depth::At(_) => return LocalPosition::Known(self.resolve_uninit(idx)), + // This local is still being initialised, meaning that + // we know its final runtime stack position, but it is + // not yet on the stack. + if !local.initialised { + return LocalPosition::Recursive(StackIdx(idx)); } + + // This local is known, but we need to account for + // uninitialised variables in this "initialiser + // stack". + return LocalPosition::Known(self.resolve_uninit(idx)); } } @@ -200,7 +182,7 @@ impl Scope { StackIdx( self.locals[..locals_idx] .iter() - .filter(|local| matches!(local.depth, Depth::At(_))) + .filter(|local| local.initialised) .count(), ) } |