Rewrite interpreter generically (#2323)
* Rewrite interpreter generically This change re-implements the Cranelift interpreter to use generic values; this makes it possible to do abstract interpretation of Cranelift instructions. In doing so, the interpretation state is extracted from the `Interpreter` structure and is accessed via a `State` trait; this makes it possible to not only more clearly observe the interpreter's state but also to interpret using a dummy state (e.g. `ImmutableRegisterState`). This addition made it possible to implement more of the Cranelift instructions (~70%, ignoring the x86-specific instructions). * Replace macros with closures
This commit is contained in:
Andrew Brown
329
cranelift/interpreter/src/value.rs
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329
cranelift/interpreter/src/value.rs
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//! The [Value] trait describes what operations can be performed on interpreter values. The
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//! interpreter usually executes using [DataValue]s so an implementation is provided here. The fact
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//! that [Value] is a trait, however, allows interpretation of Cranelift IR on other kinds of
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//! values.
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use core::convert::TryFrom;
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use core::fmt::{self, Display, Formatter};
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use cranelift_codegen::data_value::DataValue;
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use cranelift_codegen::ir::immediates::{Ieee32, Ieee64};
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use cranelift_codegen::ir::{types, Type};
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use thiserror::Error;
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pub type ValueResult<T> = Result<T, ValueError>;
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pub trait Value: Clone + From<DataValue> {
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// Identity.
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fn ty(&self) -> Type;
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fn int(n: i64, ty: Type) -> ValueResult<Self>;
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fn into_int(self) -> ValueResult<i64>;
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fn float(n: u64, ty: Type) -> ValueResult<Self>;
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fn into_float(self) -> ValueResult<f64>;
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fn is_nan(&self) -> ValueResult<bool>;
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fn bool(b: bool, ty: Type) -> ValueResult<Self>;
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fn into_bool(self) -> ValueResult<bool>;
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fn vector(v: [u8; 16], ty: Type) -> ValueResult<Self>;
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fn convert(self, kind: ValueConversionKind) -> ValueResult<Self>;
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// Comparison.
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fn eq(&self, other: &Self) -> ValueResult<bool>;
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fn gt(&self, other: &Self) -> ValueResult<bool>;
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fn ge(&self, other: &Self) -> ValueResult<bool> {
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Ok(self.eq(other)? || self.gt(other)?)
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}
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fn lt(&self, other: &Self) -> ValueResult<bool> {
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other.gt(self)
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}
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fn le(&self, other: &Self) -> ValueResult<bool> {
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Ok(other.eq(self)? || other.gt(self)?)
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}
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fn uno(&self, other: &Self) -> ValueResult<bool>;
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// Arithmetic.
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fn add(self, other: Self) -> ValueResult<Self>;
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fn sub(self, other: Self) -> ValueResult<Self>;
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fn mul(self, other: Self) -> ValueResult<Self>;
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fn div(self, other: Self) -> ValueResult<Self>;
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fn rem(self, other: Self) -> ValueResult<Self>;
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// Bitwise.
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fn shl(self, other: Self) -> ValueResult<Self>;
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fn ushr(self, other: Self) -> ValueResult<Self>;
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fn ishr(self, other: Self) -> ValueResult<Self>;
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fn rotl(self, other: Self) -> ValueResult<Self>;
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fn rotr(self, other: Self) -> ValueResult<Self>;
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fn and(self, other: Self) -> ValueResult<Self>;
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fn or(self, other: Self) -> ValueResult<Self>;
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fn xor(self, other: Self) -> ValueResult<Self>;
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fn not(self) -> ValueResult<Self>;
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}
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#[derive(Error, Debug)]
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pub enum ValueError {
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#[error("unable to convert type {1} into class {0}")]
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InvalidType(ValueTypeClass, Type),
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#[error("unable to convert value into type {0}")]
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InvalidValue(Type),
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#[error("unable to convert to primitive integer")]
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InvalidInteger(#[from] std::num::TryFromIntError),
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}
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#[derive(Debug)]
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pub enum ValueTypeClass {
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Integer,
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Boolean,
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Float,
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}
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impl Display for ValueTypeClass {
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fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
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match self {
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ValueTypeClass::Integer => write!(f, "integer"),
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ValueTypeClass::Boolean => write!(f, "boolean"),
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ValueTypeClass::Float => write!(f, "float"),
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}
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}
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}
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#[derive(Debug)]
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pub enum ValueConversionKind {
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/// Throw a [ValueError] if an exact conversion to [Type] is not possible; e.g. in `i32` to
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/// `i16`, convert `0x00001234` to `0x1234`.
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Exact(Type),
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/// Truncate the value to fit into the specified [Type]; e.g. in `i16` to `i8`, `0x1234` becomes
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/// `0x34`.
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Truncate(Type),
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/// Convert to a larger integer type, extending the sign bit; e.g. in `i8` to `i16`, `0xff`
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/// becomes `0xffff`.
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SignExtend(Type),
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/// Convert to a larger integer type, extending with zeroes; e.g. in `i8` to `i16`, `0xff`
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/// becomes `0x00ff`.
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ZeroExtend(Type),
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/// Convert a signed integer to its unsigned value of the same size; e.g. in `i8` to `u8`,
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/// `0xff` (`-1`) becomes `0xff` (`255`).
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ToUnsigned,
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/// Convert an unsigned integer to its signed value of the same size; e.g. in `u8` to `i8`,
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/// `0xff` (`255`) becomes `0xff` (`-1`).
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ToSigned,
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/// Convert a floating point number by rounding to the nearest possible value with ties to even.
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/// See `fdemote`, e.g.
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RoundNearestEven(Type),
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}
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/// Helper for creating match expressions over [DataValue].
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macro_rules! unary_match {
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( $op:tt($arg1:expr); [ $( $data_value_ty:ident ),* ] ) => {
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match $arg1 {
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$( DataValue::$data_value_ty(a) => { Ok(DataValue::$data_value_ty($op a)) } )*
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_ => unimplemented!()
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}
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};
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}
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macro_rules! binary_match {
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( $op:tt($arg1:expr, $arg2:expr); [ $( $data_value_ty:ident ),* ] ) => {
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match ($arg1, $arg2) {
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$( (DataValue::$data_value_ty(a), DataValue::$data_value_ty(b)) => { Ok(DataValue::$data_value_ty(a $op b)) } )*
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_ => unimplemented!()
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}
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};
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( $op:tt($arg1:expr, $arg2:expr); unsigned integers ) => {
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match ($arg1, $arg2) {
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(DataValue::I8(a), DataValue::I8(b)) => { Ok(DataValue::I8((u8::try_from(*a)? $op u8::try_from(*b)?) as i8)) }
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(DataValue::I16(a), DataValue::I16(b)) => { Ok(DataValue::I16((u16::try_from(*a)? $op u16::try_from(*b)?) as i16)) }
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(DataValue::I32(a), DataValue::I32(b)) => { Ok(DataValue::I32((u32::try_from(*a)? $op u32::try_from(*b)?) as i32)) }
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(DataValue::I64(a), DataValue::I64(b)) => { Ok(DataValue::I64((u64::try_from(*a)? $op u64::try_from(*b)?) as i64)) }
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_ => { Err(ValueError::InvalidType(ValueTypeClass::Integer, if !($arg1).ty().is_int() { ($arg1).ty() } else { ($arg2).ty() })) }
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}
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};
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}
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macro_rules! comparison_match {
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( $op:path[$arg1:expr, $arg2:expr]; [ $( $data_value_ty:ident ),* ] ) => {
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match ($arg1, $arg2) {
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$( (DataValue::$data_value_ty(a), DataValue::$data_value_ty(b)) => { Ok($op(a, b)) } )*
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_ => unimplemented!("comparison: {:?}, {:?}", $arg1, $arg2)
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}
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};
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}
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impl Value for DataValue {
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fn ty(&self) -> Type {
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self.ty()
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}
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fn int(n: i64, ty: Type) -> ValueResult<Self> {
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if ty.is_int() && !ty.is_vector() {
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DataValue::from_integer(n, ty).map_err(|_| ValueError::InvalidValue(ty))
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} else {
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Err(ValueError::InvalidType(ValueTypeClass::Integer, ty))
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}
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}
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fn into_int(self) -> ValueResult<i64> {
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match self {
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DataValue::I8(n) => Ok(n as i64),
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DataValue::I16(n) => Ok(n as i64),
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DataValue::I32(n) => Ok(n as i64),
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DataValue::I64(n) => Ok(n),
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_ => Err(ValueError::InvalidType(ValueTypeClass::Integer, self.ty())),
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}
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}
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fn float(bits: u64, ty: Type) -> ValueResult<Self> {
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match ty {
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types::F32 => Ok(DataValue::F32(Ieee32::with_bits(u32::try_from(bits)?))),
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types::F64 => Ok(DataValue::F64(Ieee64::with_bits(bits))),
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_ => Err(ValueError::InvalidType(ValueTypeClass::Float, ty)),
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}
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}
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fn into_float(self) -> ValueResult<f64> {
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unimplemented!()
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}
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fn is_nan(&self) -> ValueResult<bool> {
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match self {
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DataValue::F32(f) => Ok(f.is_nan()),
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DataValue::F64(f) => Ok(f.is_nan()),
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_ => Err(ValueError::InvalidType(ValueTypeClass::Float, self.ty())),
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}
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}
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fn bool(b: bool, ty: Type) -> ValueResult<Self> {
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assert!(ty.is_bool());
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Ok(DataValue::B(b))
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}
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fn into_bool(self) -> ValueResult<bool> {
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match self {
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DataValue::B(b) => Ok(b),
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_ => Err(ValueError::InvalidType(ValueTypeClass::Boolean, self.ty())),
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}
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}
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fn vector(_v: [u8; 16], _ty: Type) -> ValueResult<Self> {
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unimplemented!()
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}
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fn convert(self, kind: ValueConversionKind) -> ValueResult<Self> {
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Ok(match kind {
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ValueConversionKind::Exact(ty) => match (self, ty) {
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// TODO a lot to do here: from bmask to ireduce to raw_bitcast...
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(DataValue::I64(n), types::I32) => DataValue::I32(i32::try_from(n)?),
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(DataValue::B(b), t) if t.is_bool() => DataValue::B(b),
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(dv, _) => unimplemented!("conversion: {} -> {:?}", dv.ty(), kind),
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},
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ValueConversionKind::Truncate(ty) => match (self.ty(), ty) {
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(types::I64, types::I32) => unimplemented!(),
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(types::I64, types::I16) => unimplemented!(),
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(types::I64, types::I8) => unimplemented!(),
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(types::I32, types::I16) => unimplemented!(),
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(types::I32, types::I8) => unimplemented!(),
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(types::I16, types::I8) => unimplemented!(),
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_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
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},
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ValueConversionKind::SignExtend(ty) => match (self.ty(), ty) {
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(types::I8, types::I16) => unimplemented!(),
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(types::I8, types::I32) => unimplemented!(),
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(types::I8, types::I64) => unimplemented!(),
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(types::I16, types::I32) => unimplemented!(),
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(types::I16, types::I64) => unimplemented!(),
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(types::I32, types::I64) => unimplemented!(),
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_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
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},
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ValueConversionKind::ZeroExtend(ty) => match (self.ty(), ty) {
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(types::I8, types::I16) => unimplemented!(),
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(types::I8, types::I32) => unimplemented!(),
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(types::I8, types::I64) => unimplemented!(),
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(types::I16, types::I32) => unimplemented!(),
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(types::I16, types::I64) => unimplemented!(),
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(types::I32, types::I64) => unimplemented!(),
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_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
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},
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ValueConversionKind::ToUnsigned => match self {
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DataValue::I8(n) => DataValue::U8(n as u8),
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DataValue::I16(n) => DataValue::U16(n as u16),
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DataValue::I32(n) => DataValue::U32(n as u32),
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DataValue::I64(n) => DataValue::U64(n as u64),
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_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
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},
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ValueConversionKind::ToSigned => match self {
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DataValue::U8(n) => DataValue::I8(n as i8),
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DataValue::U16(n) => DataValue::I16(n as i16),
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DataValue::U32(n) => DataValue::I32(n as i32),
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DataValue::U64(n) => DataValue::I64(n as i64),
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_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
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},
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ValueConversionKind::RoundNearestEven(ty) => match (self.ty(), ty) {
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(types::F64, types::F32) => unimplemented!(),
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_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
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},
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})
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}
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fn eq(&self, other: &Self) -> ValueResult<bool> {
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comparison_match!(PartialEq::eq[&self, &other]; [I8, I16, I32, I64, U8, U16, U32, U64, F32, F64])
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}
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fn gt(&self, other: &Self) -> ValueResult<bool> {
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comparison_match!(PartialOrd::gt[&self, &other]; [I8, I16, I32, I64, U8, U16, U32, U64, F32, F64])
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}
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fn uno(&self, other: &Self) -> ValueResult<bool> {
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Ok(self.is_nan()? || other.is_nan()?)
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}
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fn add(self, other: Self) -> ValueResult<Self> {
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binary_match!(+(&self, &other); [I8, I16, I32, I64]) // TODO: floats must handle NaNs, +/-0
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}
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fn sub(self, other: Self) -> ValueResult<Self> {
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binary_match!(-(&self, &other); [I8, I16, I32, I64]) // TODO: floats must handle NaNs, +/-0
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}
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fn mul(self, other: Self) -> ValueResult<Self> {
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binary_match!(*(&self, &other); [I8, I16, I32, I64])
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}
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fn div(self, other: Self) -> ValueResult<Self> {
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binary_match!(/(&self, &other); [I8, I16, I32, I64])
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}
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fn rem(self, other: Self) -> ValueResult<Self> {
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binary_match!(%(&self, &other); [I8, I16, I32, I64])
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}
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fn shl(self, other: Self) -> ValueResult<Self> {
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binary_match!(<<(&self, &other); [I8, I16, I32, I64])
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}
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fn ushr(self, other: Self) -> ValueResult<Self> {
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binary_match!(>>(&self, &other); unsigned integers)
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}
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fn ishr(self, other: Self) -> ValueResult<Self> {
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binary_match!(>>(&self, &other); [I8, I16, I32, I64])
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}
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fn rotl(self, _other: Self) -> ValueResult<Self> {
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unimplemented!()
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}
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fn rotr(self, _other: Self) -> ValueResult<Self> {
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unimplemented!()
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}
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fn and(self, other: Self) -> ValueResult<Self> {
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binary_match!(&(&self, &other); [I8, I16, I32, I64])
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}
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fn or(self, other: Self) -> ValueResult<Self> {
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binary_match!(|(&self, &other); [I8, I16, I32, I64])
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}
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fn xor(self, other: Self) -> ValueResult<Self> {
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binary_match!(^(&self, &other); [I8, I16, I32, I64])
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}
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fn not(self) -> ValueResult<Self> {
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unary_match!(!(&self); [I8, I16, I32, I64])
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}
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}
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