From 0b06d946062f254d8e097f7a0a0ad308b159d739 Mon Sep 17 00:00:00 2001 From: Griffin Smith Date: Sun, 9 Oct 2022 13:18:32 -0400 Subject: refactor(tvix/eval): Abstract away calling functions The process of calling a function from a builtin, especially if it's got more than 1 arrgument, is reasonably involved and easy to get wrong due to having to interact directly with the stack - instead of having that done entirely manually in builtins, this wraps it up in a new `call_with` function which handles pushing arguments onto the stack and recursively calling the (partially applied) function. Change-Id: I14700c639a0deca53b9a060f6d70dbc7762e9007 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6910 Autosubmit: grfn Reviewed-by: tazjin Tested-by: BuildkiteCI --- tvix/eval/src/builtins/mod.rs | 34 +++++++--------------------------- tvix/eval/src/vm.rs | 25 +++++++++++++++++++++++++ 2 files changed, 32 insertions(+), 27 deletions(-) (limited to 'tvix') diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index f32a29a20660..5819796236cd 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -60,10 +60,7 @@ fn pure_builtins() -> Vec { }), Builtin::new("all", &[true, true], |args: Vec, vm: &mut VM| { for value in args[1].to_list()?.into_iter() { - let pred_result = { - vm.push(value); - vm.call_value(&args[0]) - }?; + let pred_result = vm.call_with(&args[0], [value])?; if !pred_result.force(vm)?.as_bool()? { return Ok(Value::Bool(false)); @@ -74,10 +71,7 @@ fn pure_builtins() -> Vec { }), Builtin::new("any", &[true, true], |args: Vec, vm: &mut VM| { for value in args[1].to_list()?.into_iter() { - let pred_result = { - vm.push(value); - vm.call_value(&args[0]) - }?; + let pred_result = vm.call_with(&args[0], [value])?; if pred_result.force(vm)?.as_bool()? { return Ok(Value::Bool(true)); @@ -170,8 +164,7 @@ fn pure_builtins() -> Vec { let list = args[1].to_list()?; let mut res = Vec::new(); for val in list { - vm.push(val); - res.extend(vm.call_value(&args[0])?.force(vm)?.to_list()?); + res.extend(vm.call_with(&args[0], [val])?.force(vm)?.to_list()?); } Ok(Value::List(res.into())) }, @@ -198,9 +191,7 @@ fn pure_builtins() -> Vec { list.into_iter() .filter_map(|elem| { - vm.push(elem.clone()); - - let result = match vm.call_value(&args[0]) { + let result = match vm.call_with(&args[0], [elem.clone()]) { Err(err) => return Some(Err(err)), Ok(result) => result, }; @@ -231,10 +222,7 @@ fn pure_builtins() -> Vec { let op = args.pop().unwrap(); for val in list { val.force(vm)?; - vm.push(val); - vm.push(res); - let partial = vm.call_value(&op)?; - res = vm.call_value(&partial)?; + res = vm.call_with(&op, [val, res])?; } Ok(res) @@ -243,10 +231,7 @@ fn pure_builtins() -> Vec { Builtin::new("genList", &[true, true], |args: Vec, vm: &mut VM| { let len = args[1].as_int()?; (0..len) - .map(|i| { - vm.push(i.into()); - vm.call_value(&args[0]) - }) + .map(|i| vm.call_with(&args[0], [i.into()])) .collect::, _>>() .map(|list| Value::List(NixList::from(list))) .map_err(Into::into) @@ -269,12 +254,7 @@ fn pure_builtins() -> Vec { let list: NixList = args[1].to_list()?; list.into_iter() - .map(|val| { - // Leave the argument on the stack before calling the - // function. - vm.push(val); - vm.call_value(&args[0]) - }) + .map(|val| vm.call_with(&args[0], [val])) .collect::, _>>() .map(|list| Value::List(NixList::from(list))) .map_err(Into::into) diff --git a/tvix/eval/src/vm.rs b/tvix/eval/src/vm.rs index 9d28c7be1b93..b89b61f7626a 100644 --- a/tvix/eval/src/vm.rs +++ b/tvix/eval/src/vm.rs @@ -229,6 +229,31 @@ impl<'o> VM<'o> { } } + /// Call the given `callable` value with the given list of `args` + /// + /// # Panics + /// + /// Panics if the passed list of `args` is empty + #[track_caller] + pub fn call_with(&mut self, callable: &Value, args: I) -> EvalResult + where + I: IntoIterator, + { + let mut num_args = 0_usize; + for arg in args { + num_args += 1; + self.push(arg); + } + if num_args == 0 { + panic!("call_with called with an empty list of args"); + } + let mut res = self.call_value(callable)?; + for _ in 0..(num_args - 1) { + res = self.call_value(&res)?; + } + Ok(res) + } + fn tail_call_value(&mut self, callable: Value) -> EvalResult<()> { match callable { Value::Builtin(builtin) => self.call_builtin(builtin), -- cgit 1.4.1