d5ee893fb1
As suggested by sterni in cl/6453. Change-Id: I3cf80d97c11fd7d085ab510f6be4b5f937c791ec Reviewed-on: https://cl.tvl.fyi/c/depot/+/6562 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
145 lines
3.3 KiB
Rust
145 lines
3.3 KiB
Rust
//! This module implements the instruction set running on the abstract
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//! machine implemented by tvix.
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use std::ops::{AddAssign, Sub};
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/// Index of a constant in the current code chunk.
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#[repr(transparent)]
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#[derive(Clone, Copy, Debug)]
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pub struct ConstantIdx(pub usize);
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/// Index of an instruction in the current code chunk.
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#[repr(transparent)]
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#[derive(Clone, Copy, Debug)]
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pub struct CodeIdx(pub usize);
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impl AddAssign<usize> for CodeIdx {
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fn add_assign(&mut self, rhs: usize) {
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*self = CodeIdx(self.0 + rhs)
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}
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}
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impl Sub<usize> for CodeIdx {
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type Output = Self;
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fn sub(self, rhs: usize) -> Self::Output {
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CodeIdx(self.0 - rhs)
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}
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}
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/// Index of a value in the runtime stack.
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#[repr(transparent)]
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#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd)]
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pub struct StackIdx(pub usize);
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/// Index of an upvalue within a closure's upvalue list.
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#[repr(transparent)]
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub struct UpvalueIdx(pub usize);
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/// Offset by which an instruction pointer should change in a jump.
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#[repr(transparent)]
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#[derive(Clone, Copy, Debug)]
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pub struct JumpOffset(pub usize);
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/// Provided count for an instruction (could represent e.g. a number
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/// of elements).
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#[repr(transparent)]
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#[derive(Clone, Copy, Debug)]
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pub struct Count(pub usize);
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#[warn(variant_size_differences)]
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#[derive(Clone, Copy, Debug)]
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pub enum OpCode {
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/// Push a constant onto the stack.
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OpConstant(ConstantIdx),
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/// Discard a value from the stack.
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OpPop,
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// Push a literal value.
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OpNull,
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OpTrue,
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OpFalse,
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// Unary operators
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OpInvert,
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OpNegate,
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// Arithmetic binary operators
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OpAdd,
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OpSub,
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OpMul,
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OpDiv,
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// Comparison operators
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OpEqual,
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OpLess,
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OpLessOrEq,
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OpMore,
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OpMoreOrEq,
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// Logical operators & generic jumps
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OpJump(JumpOffset),
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OpJumpIfTrue(JumpOffset),
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OpJumpIfFalse(JumpOffset),
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OpJumpIfNotFound(JumpOffset),
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// Attribute sets
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OpAttrs(Count),
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OpAttrPath(Count),
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OpAttrsUpdate,
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OpAttrsSelect,
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OpAttrsTrySelect,
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OpAttrsIsSet,
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// `with`-handling
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OpPushWith(StackIdx),
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OpPopWith,
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OpResolveWith,
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OpResolveWithOrUpvalue(UpvalueIdx),
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// Lists
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OpList(Count),
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OpConcat,
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// Strings
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OpInterpolate(Count),
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// Type assertion operators
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OpAssertBool,
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/// Access local identifiers with statically known positions.
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OpGetLocal(StackIdx),
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/// Close scopes while leaving their expression value around.
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OpCloseScope(Count), // number of locals to pop
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/// Asserts stack top is a boolean, and true.
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OpAssert,
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// Lambdas & closures
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OpCall,
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OpTailCall,
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OpGetUpvalue(UpvalueIdx),
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OpClosure(ConstantIdx),
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// Thunks
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OpThunk(ConstantIdx),
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OpForce,
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/// Finalise initialisation of the upvalues of the value in the
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/// given stack index after the scope is fully bound.
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OpFinalise(StackIdx),
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// The closure and thunk creation instructions have a variable
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// number of arguments to the instruction, which is represented
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// here by making their data part of the opcodes.
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//
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// The VM skips over these by advancing the instruction pointer
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// according to the count.
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DataLocalIdx(StackIdx),
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DataDeferredLocal(StackIdx),
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DataUpvalueIdx(UpvalueIdx),
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DataCaptureWith,
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}
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