tvl-depot/tvix/eval/src/opcode.rs
Vincent Ambo d1798444be feat(tvix/eval): Add Compiler::thunk method for emitting thunks
The logic in this method is *very* similar to `compile_lambda`. It is
intended to be called around any expression that should be
thunked (such as function applications, attribute set values, etc.).

Change-Id: Idfbb2daa9f4b735095378fb9c39a2fd07c8cff91
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6344
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-06 14:58:52 +00:00

128 lines
3 KiB
Rust

//! This module implements the instruction set running on the abstract
//! machine implemented by tvix.
/// Index of a constant in the current code chunk.
#[repr(transparent)]
#[derive(Clone, Copy, Debug)]
pub struct ConstantIdx(pub usize);
/// Index of an instruction in the current code chunk.
#[repr(transparent)]
#[derive(Clone, Copy, Debug)]
pub struct CodeIdx(pub usize);
/// Index of a value in the runtime stack.
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct StackIdx(pub usize);
/// Index of an upvalue within a closure's upvalue list.
#[repr(transparent)]
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct UpvalueIdx(pub usize);
/// Offset by which an instruction pointer should change in a jump.
#[repr(transparent)]
#[derive(Clone, Copy, Debug)]
pub struct JumpOffset(pub usize);
/// Provided count for an instruction (could represent e.g. a number
/// of elements).
#[repr(transparent)]
#[derive(Clone, Copy, Debug)]
pub struct Count(pub usize);
#[warn(variant_size_differences)]
#[derive(Clone, Copy, Debug)]
pub enum OpCode {
// Push a constant onto the stack.
OpConstant(ConstantIdx),
// Discard a value from the stack.
OpPop,
// Push a literal value.
OpNull,
OpTrue,
OpFalse,
// Unary operators
OpInvert,
OpNegate,
// Arithmetic binary operators
OpAdd,
OpSub,
OpMul,
OpDiv,
// Comparison operators
OpEqual,
OpLess,
OpLessOrEq,
OpMore,
OpMoreOrEq,
// Logical operators & generic jumps
OpJump(JumpOffset),
OpJumpIfTrue(JumpOffset),
OpJumpIfFalse(JumpOffset),
OpJumpIfNotFound(JumpOffset),
// Attribute sets
OpAttrs(Count),
OpAttrPath(Count),
OpAttrsUpdate,
OpAttrsSelect,
OpAttrsTrySelect,
OpAttrsIsSet,
// `with`-handling
OpPushWith(StackIdx),
OpPopWith,
OpResolveWith,
OpResolveWithOrUpvalue(UpvalueIdx),
// Lists
OpList(Count),
OpConcat,
// Strings
OpInterpolate(Count),
// Type assertion operators
OpAssertBool,
// Access local identifiers with statically known positions.
OpGetLocal(StackIdx),
// Close scopes while leaving their expression value around.
OpCloseScope(Count), // number of locals to pop
// Asserts stack top is a boolean, and true.
OpAssert,
// Lambdas & closures
OpCall,
OpGetUpvalue(UpvalueIdx),
OpClosure(ConstantIdx),
// Thunks
OpThunk(ConstantIdx),
/// Finalise initialisation of the upvalues of the value in the
/// given stack index after the scope is fully bound.
OpFinalise(StackIdx),
// The closure and thunk creation instructions have a variable
// number of arguments to the instruction, which is represented
// here by making their data part of the opcodes.
//
// The VM skips over these by advancing the instruction pointer
// according to the count.
DataLocalIdx(StackIdx),
DataDeferredLocal(StackIdx),
DataUpvalueIdx(UpvalueIdx),
DataDynamicIdx(ConstantIdx),
DataDynamicAncestor(UpvalueIdx),
}