diff options
Diffstat (limited to 'tvix/eval/src/vm/mod.rs')
| -rw-r--r-- | tvix/eval/src/vm/mod.rs | 217 |
1 files changed, 152 insertions, 65 deletions
diff --git a/tvix/eval/src/vm/mod.rs b/tvix/eval/src/vm/mod.rs index fbecab9590..60039eab33 100644 --- a/tvix/eval/src/vm/mod.rs +++ b/tvix/eval/src/vm/mod.rs @@ -12,6 +12,7 @@ pub mod generators; mod macros; +use codemap::Span; use serde_json::json; use std::{cmp::Ordering, collections::HashMap, ops::DerefMut, path::PathBuf, rc::Rc}; @@ -39,15 +40,75 @@ use generators::{call_functor, Generator, GeneratorState}; use self::generators::{VMRequest, VMResponse}; +/// Internal helper trait for taking a span from a variety of types, to make use +/// of `WithSpan` (defined below) more ergonomic at call sites. +trait GetSpan { + fn get_span(self) -> Span; +} + +impl<'o> GetSpan for &VM<'o> { + fn get_span(self) -> Span { + self.reasonable_span.span() + } +} + +impl GetSpan for &CallFrame { + fn get_span(self) -> Span { + self.current_span() + } +} + +impl GetSpan for &LightSpan { + fn get_span(self) -> Span { + self.span() + } +} + +impl GetSpan for Span { + fn get_span(self) -> Span { + self + } +} + /// Internal helper trait for ergonomically converting from a `Result<T, -/// ErrorKind>` to a `Result<T, Error>` using the current span of a call frame. -trait WithSpan<T> { - fn with_span(self, frame: &CallFrame) -> Result<T, Error>; +/// ErrorKind>` to a `Result<T, Error>` using the current span of a call frame, +/// and chaining the VM's frame stack around it for printing a cause chain. +trait WithSpan<T, S: GetSpan> { + fn with_span(self, top_span: S, vm: &VM) -> Result<T, Error>; } -impl<T> WithSpan<T> for Result<T, ErrorKind> { - fn with_span(self, frame: &CallFrame) -> Result<T, Error> { - self.map_err(|kind| frame.error(kind)) +impl<T, S: GetSpan> WithSpan<T, S> for Result<T, ErrorKind> { + fn with_span(self, top_span: S, vm: &VM) -> Result<T, Error> { + match self { + Ok(something) => Ok(something), + Err(kind) => { + let mut error = Error::new(kind, top_span.get_span()); + + // Short-circuit the wrapping if we're dealing with tryEval, in + // which case the error is hidden and does not need to be + // exhaustive. + if !vm.try_eval_frames.is_empty() && error.kind.is_catchable() { + return Err(error); + } + + // Wrap the top-level error in chaining errors for each element + // of the frame stack. + for frame in vm.frames.iter().rev() { + match frame { + Frame::CallFrame { span, .. } => { + error = + Error::new(ErrorKind::BytecodeError(Box::new(error)), span.span()); + } + Frame::Generator { span, .. } => { + error = + Error::new(ErrorKind::NativeError(Box::new(error)), span.span()); + } + } + } + + Err(error) + } + } } } @@ -86,10 +147,16 @@ impl CallFrame { op } - /// Construct an error from the given ErrorKind and the source span of the - /// current instruction. - pub fn error(&self, kind: ErrorKind) -> Error { - Error::new(kind, self.chunk().get_span(self.ip - 1)) + /// Construct an error result from the given ErrorKind and the source span + /// of the current instruction. + pub fn error<T>(&self, vm: &VM, kind: ErrorKind) -> Result<T, Error> { + Err(kind).with_span(self, vm) + } + + /// Returns the current span. This is potentially expensive and should only + /// be used when actually constructing an error or warning. + pub fn current_span(&self) -> Span { + self.chunk().get_span(self.ip - 1) } /// Returns the information needed to calculate the current span, @@ -475,23 +542,26 @@ impl<'o> VM<'o> { } OpCode::OpAttrsSelect => { - let key = self.stack_pop().to_str().with_span(&frame)?; - let attrs = self.stack_pop().to_attrs().with_span(&frame)?; + let key = self.stack_pop().to_str().with_span(&frame, self)?; + let attrs = self.stack_pop().to_attrs().with_span(&frame, self)?; match attrs.select(key.as_str()) { Some(value) => self.stack.push(value.clone()), None => { - return Err(frame.error(ErrorKind::AttributeNotFound { - name: key.as_str().to_string(), - })) + return frame.error( + self, + ErrorKind::AttributeNotFound { + name: key.as_str().to_string(), + }, + ); } } } OpCode::OpJumpIfFalse(JumpOffset(offset)) => { debug_assert!(offset != 0); - if !self.stack_peek(0).as_bool().with_span(&frame)? { + if !self.stack_peek(0).as_bool().with_span(&frame, self)? { frame.ip += offset; } } @@ -501,7 +571,7 @@ impl<'o> VM<'o> { } OpCode::OpAttrsTrySelect => { - let key = self.stack_pop().to_str().with_span(&frame)?; + let key = self.stack_pop().to_str().with_span(&frame, self)?; let value = match self.stack_pop() { Value::Attrs(attrs) => match attrs.select(key.as_str()) { Some(value) => value.clone(), @@ -550,24 +620,27 @@ impl<'o> VM<'o> { OpCode::OpAssertBool => { let val = self.stack_peek(0); if !val.is_bool() { - return Err(frame.error(ErrorKind::TypeError { - expected: "bool", - actual: val.type_of(), - })); + return frame.error( + self, + ErrorKind::TypeError { + expected: "bool", + actual: val.type_of(), + }, + ); } } OpCode::OpAttrs(Count(count)) => self.run_attrset(&frame, count)?, OpCode::OpAttrsUpdate => { - let rhs = self.stack_pop().to_attrs().with_span(&frame)?; - let lhs = self.stack_pop().to_attrs().with_span(&frame)?; + let rhs = self.stack_pop().to_attrs().with_span(&frame, self)?; + let lhs = self.stack_pop().to_attrs().with_span(&frame, self)?; self.stack.push(Value::attrs(lhs.update(*rhs))) } OpCode::OpInvert => { - let v = self.stack_pop().as_bool().with_span(&frame)?; + let v = self.stack_pop().as_bool().with_span(&frame, self)?; self.stack.push(Value::Bool(!v)); } @@ -580,13 +653,13 @@ impl<'o> VM<'o> { OpCode::OpJumpIfTrue(JumpOffset(offset)) => { debug_assert!(offset != 0); - if self.stack_peek(0).as_bool().with_span(&frame)? { + if self.stack_peek(0).as_bool().with_span(&frame, self)? { frame.ip += offset; } } OpCode::OpHasAttr => { - let key = self.stack_pop().to_str().with_span(&frame)?; + let key = self.stack_pop().to_str().with_span(&frame, self)?; let result = match self.stack_pop() { Value::Attrs(attrs) => attrs.contains(key.as_str()), @@ -599,13 +672,21 @@ impl<'o> VM<'o> { } OpCode::OpConcat => { - let rhs = self.stack_pop().to_list().with_span(&frame)?.into_inner(); - let lhs = self.stack_pop().to_list().with_span(&frame)?.into_inner(); + let rhs = self + .stack_pop() + .to_list() + .with_span(&frame, self)? + .into_inner(); + let lhs = self + .stack_pop() + .to_list() + .with_span(&frame, self)? + .into_inner(); self.stack.push(Value::List(NixList::from(lhs + rhs))) } OpCode::OpResolveWith => { - let ident = self.stack_pop().to_str().with_span(&frame)?; + let ident = self.stack_pop().to_str().with_span(&frame, self)?; // Re-enqueue this frame. let op_span = frame.current_light_span(); @@ -664,13 +745,16 @@ impl<'o> VM<'o> { "OpValidateClosedFormals called within the frame of a lambda without formals", ); - let args = self.stack_peek(0).to_attrs().with_span(&frame)?; + let args = self.stack_peek(0).to_attrs().with_span(&frame, self)?; for arg in args.keys() { if !formals.contains(arg) { - return Err(frame.error(ErrorKind::UnexpectedArgument { - arg: arg.clone(), - formals_span: formals.span, - })); + return frame.error( + self, + ErrorKind::UnexpectedArgument { + arg: arg.clone(), + formals_span: formals.span, + }, + ); } } } @@ -692,14 +776,14 @@ impl<'o> VM<'o> { OpCode::OpSub => { let b = self.stack_pop(); let a = self.stack_pop(); - let result = arithmetic_op!(&a, &b, -).with_span(&frame)?; + let result = arithmetic_op!(&a, &b, -).with_span(&frame, self)?; self.stack.push(result); } OpCode::OpMul => { let b = self.stack_pop(); let a = self.stack_pop(); - let result = arithmetic_op!(&a, &b, *).with_span(&frame)?; + let result = arithmetic_op!(&a, &b, *).with_span(&frame, self)?; self.stack.push(result); } @@ -707,15 +791,15 @@ impl<'o> VM<'o> { let b = self.stack_pop(); match b { - Value::Integer(0) => return Err(frame.error(ErrorKind::DivisionByZero)), + Value::Integer(0) => return frame.error(self, ErrorKind::DivisionByZero), Value::Float(b) if b == 0.0_f64 => { - return Err(frame.error(ErrorKind::DivisionByZero)) + return frame.error(self, ErrorKind::DivisionByZero) } _ => {} }; let a = self.stack_pop(); - let result = arithmetic_op!(&a, &b, /).with_span(&frame)?; + let result = arithmetic_op!(&a, &b, /).with_span(&frame, self)?; self.stack.push(result); } @@ -723,10 +807,13 @@ impl<'o> VM<'o> { Value::Integer(i) => self.stack.push(Value::Integer(-i)), Value::Float(f) => self.stack.push(Value::Float(-f)), v => { - return Err(frame.error(ErrorKind::TypeError { - expected: "number (either int or float)", - actual: v.type_of(), - })); + return frame.error( + self, + ErrorKind::TypeError { + expected: "number (either int or float)", + actual: v.type_of(), + }, + ); } }, @@ -740,7 +827,7 @@ impl<'o> VM<'o> { let resolved = self .nix_search_path .resolve(&*self.io_handle, *path) - .with_span(&frame)?; + .with_span(&frame, self)?; self.stack.push(resolved.into()); } @@ -751,9 +838,12 @@ impl<'o> VM<'o> { Value::UnresolvedPath(path) => { match dirs::home_dir() { None => { - return Err(frame.error(ErrorKind::RelativePathResolution( - "failed to determine home directory".into(), - ))); + return frame.error( + self, + ErrorKind::RelativePathResolution( + "failed to determine home directory".into(), + ), + ); } Some(mut buf) => { buf.push(*path); @@ -774,7 +864,7 @@ impl<'o> VM<'o> { } OpCode::OpAssertFail => { - return Err(frame.error(ErrorKind::AssertionFailed)); + frame.error(self, ErrorKind::AssertionFailed)?; } // Data-carrying operands should never be executed, @@ -802,7 +892,7 @@ impl<'o> VM<'o> { fn run_attrset(&mut self, frame: &CallFrame, count: usize) -> EvalResult<()> { let attrs = NixAttrs::construct(count, self.stack.split_off(self.stack.len() - count * 2)) - .with_span(frame)?; + .with_span(frame, self)?; self.stack.push(Value::attrs(attrs)); Ok(()) @@ -842,7 +932,7 @@ impl<'o> VM<'o> { let mut out = String::new(); for _ in 0..count { - out.push_str(self.stack_pop().to_str().with_span(frame)?.as_str()); + out.push_str(self.stack_pop().to_str().with_span(frame, self)?.as_str()); } self.stack.push(Value::String(out.into())); @@ -855,12 +945,6 @@ impl<'o> VM<'o> { self.reasonable_span.clone() } - /// Construct an error from the given ErrorKind and the source - /// span of the current instruction. - pub fn error(&self, kind: ErrorKind) -> Error { - Error::new(kind, self.reasonable_span.span()) - } - /// Apply an argument from the stack to a builtin, and attempt to call it. /// /// All calls are tail-calls in Tvix, as every function application is a @@ -932,7 +1016,7 @@ impl<'o> VM<'o> { self.enqueue_generator("__functor call", gen_span, |co| call_functor(co, val)); Ok(()) } - v => Err(self.error(ErrorKind::NotCallable(v.type_of()))), + v => Err(ErrorKind::NotCallable(v.type_of())).with_span(&span, self), } } @@ -951,14 +1035,17 @@ impl<'o> VM<'o> { let val = match self.stack.get(idx) { Some(val) => val.clone(), None => { - return Err(frame.error(ErrorKind::TvixBug { - msg: "upvalue to be captured was missing on stack", - metadata: Some(Rc::new(json!({ - "ip": format!("{:#x}", frame.ip.0 - 1), - "stack_idx(relative)": stack_idx, - "stack_idx(absolute)": idx, - }))), - })) + return frame.error( + self, + ErrorKind::TvixBug { + msg: "upvalue to be captured was missing on stack", + metadata: Some(Rc::new(json!({ + "ip": format!("{:#x}", frame.ip.0 - 1), + "stack_idx(relative)": stack_idx, + "stack_idx(absolute)": idx, + }))), + }, + ); } }; |