Files
wasmtime/cranelift/codegen/meta/src/cdsl/ast.rs
2019-05-23 14:31:00 +02:00

598 lines
17 KiB
Rust

use crate::cdsl::formats::FormatRegistry;
use crate::cdsl::inst::{InstSpec, Instruction, InstructionPredicate};
use crate::cdsl::operands::{OperandKind, OperandKindFields};
use crate::cdsl::types::ValueType;
use crate::cdsl::typevar::{TypeSetBuilder, TypeVar};
use cranelift_entity::{entity_impl, PrimaryMap};
use std::fmt;
pub enum Expr {
Var(VarIndex),
Literal(Literal),
Apply(Apply),
}
impl Expr {
pub fn maybe_literal(&self) -> Option<&Literal> {
match &self {
Expr::Literal(lit) => Some(lit),
_ => None,
}
}
pub fn maybe_var(&self) -> Option<VarIndex> {
if let Expr::Var(var) = &self {
Some(*var)
} else {
None
}
}
pub fn unwrap_var(&self) -> VarIndex {
self.maybe_var()
.expect("tried to unwrap a non-Var content in Expr::unwrap_var")
}
pub fn to_rust_code(&self, var_pool: &VarPool) -> String {
match self {
Expr::Var(var_index) => var_pool.get(*var_index).to_rust_code(),
Expr::Literal(literal) => literal.to_rust_code(),
Expr::Apply(a) => a.to_rust_code(var_pool),
}
}
}
/// An AST definition associates a set of variables with the values produced by an expression.
pub struct Def {
pub apply: Apply,
pub defined_vars: Vec<VarIndex>,
}
impl Def {
pub fn to_comment_string(&self, var_pool: &VarPool) -> String {
let results = self
.defined_vars
.iter()
.map(|&x| var_pool.get(x).name)
.collect::<Vec<_>>();
let results = if results.len() == 1 {
results[0].to_string()
} else {
format!("({})", results.join(", "))
};
format!("{} << {}", results, self.apply.to_comment_string(var_pool))
}
}
pub struct DefPool {
pool: PrimaryMap<DefIndex, Def>,
}
impl DefPool {
pub fn new() -> Self {
Self {
pool: PrimaryMap::new(),
}
}
pub fn get(&self, index: DefIndex) -> &Def {
self.pool.get(index).unwrap()
}
pub fn get_mut(&mut self, index: DefIndex) -> &mut Def {
self.pool.get_mut(index).unwrap()
}
pub fn next_index(&self) -> DefIndex {
self.pool.next_key()
}
pub fn create(&mut self, apply: Apply, defined_vars: Vec<VarIndex>) -> DefIndex {
self.pool.push(Def {
apply,
defined_vars,
})
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct DefIndex(u32);
entity_impl!(DefIndex);
#[derive(Debug, Clone)]
enum LiteralValue {
/// A value of an enumerated immediate operand.
///
/// Some immediate operand kinds like `intcc` and `floatcc` have an enumerated range of values
/// corresponding to a Rust enum type. An `Enumerator` object is an AST leaf node representing one
/// of the values.
Enumerator(&'static str),
/// A bitwise value of an immediate operand, used for bitwise exact floating point constants.
Bits(u64),
/// A value of an integer immediate operand.
Int(i64),
}
#[derive(Clone)]
pub struct Literal {
kind: OperandKind,
value: LiteralValue,
}
impl fmt::Debug for Literal {
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(
fmt,
"Literal(kind={}, value={:?})",
self.kind.name, self.value
)
}
}
impl Literal {
pub fn enumerator_for(kind: &OperandKind, value: &'static str) -> Self {
if let OperandKindFields::ImmEnum(values) = &kind.fields {
assert!(
values.get(value).is_some(),
format!(
"nonexistent value '{}' in enumeration '{}'",
value, kind.name
)
);
} else {
panic!("enumerator is for enum values");
}
Self {
kind: kind.clone(),
value: LiteralValue::Enumerator(value),
}
}
pub fn bits(kind: &OperandKind, bits: u64) -> Self {
match kind.fields {
OperandKindFields::ImmValue => {}
_ => panic!("bits_of is for immediate scalar types"),
}
Self {
kind: kind.clone(),
value: LiteralValue::Bits(bits),
}
}
pub fn constant(kind: &OperandKind, value: i64) -> Self {
match kind.fields {
OperandKindFields::ImmValue => {}
_ => panic!("bits_of is for immediate scalar types"),
}
Self {
kind: kind.clone(),
value: LiteralValue::Int(value),
}
}
pub fn to_rust_code(&self) -> String {
let maybe_values = match &self.kind.fields {
OperandKindFields::ImmEnum(values) => Some(values),
OperandKindFields::ImmValue => None,
_ => panic!("impossible per construction"),
};
match self.value {
LiteralValue::Enumerator(value) => {
format!("{}::{}", self.kind.rust_type, maybe_values.unwrap()[value])
}
LiteralValue::Bits(bits) => format!("{}::with_bits({:#x})", self.kind.rust_type, bits),
LiteralValue::Int(val) => val.to_string(),
}
}
}
#[derive(Clone, Copy, Debug)]
pub enum PatternPosition {
Source,
Destination,
}
/// A free variable.
///
/// When variables are used in `XForms` with source and destination patterns, they are classified
/// as follows:
///
/// Input values: Uses in the source pattern with no preceding def. These may appear as inputs in
/// the destination pattern too, but no new inputs can be introduced.
///
/// Output values: Variables that are defined in both the source and destination pattern. These
/// values may have uses outside the source pattern, and the destination pattern must compute the
/// same value.
///
/// Intermediate values: Values that are defined in the source pattern, but not in the destination
/// pattern. These may have uses outside the source pattern, so the defining instruction can't be
/// deleted immediately.
///
/// Temporary values are defined only in the destination pattern.
pub struct Var {
pub name: &'static str,
/// The `Def` defining this variable in a source pattern.
pub src_def: Option<DefIndex>,
/// The `Def` defining this variable in a destination pattern.
pub dst_def: Option<DefIndex>,
/// TypeVar representing the type of this variable.
type_var: Option<TypeVar>,
/// Is this the original type variable, or has it be redefined with set_typevar?
is_original_type_var: bool,
}
impl Var {
fn new(name: &'static str) -> Self {
Self {
name,
src_def: None,
dst_def: None,
type_var: None,
is_original_type_var: false,
}
}
/// Is this an input value to the src pattern?
pub fn is_input(&self) -> bool {
self.src_def.is_none() && self.dst_def.is_none()
}
/// Is this an output value, defined in both src and dst patterns?
pub fn is_output(&self) -> bool {
self.src_def.is_some() && self.dst_def.is_some()
}
/// Is this an intermediate value, defined only in the src pattern?
pub fn is_intermediate(&self) -> bool {
self.src_def.is_some() && self.dst_def.is_none()
}
/// Is this a temp value, defined only in the dst pattern?
pub fn is_temp(&self) -> bool {
self.src_def.is_none() && self.dst_def.is_some()
}
/// Get the def of this variable according to the position.
pub fn get_def(&self, position: PatternPosition) -> Option<DefIndex> {
match position {
PatternPosition::Source => self.src_def,
PatternPosition::Destination => self.dst_def,
}
}
pub fn set_def(&mut self, position: PatternPosition, def: DefIndex) {
assert!(
self.get_def(position).is_none(),
format!("redefinition of variable {}", self.name)
);
match position {
PatternPosition::Source => {
self.src_def = Some(def);
}
PatternPosition::Destination => {
self.dst_def = Some(def);
}
}
}
/// Get the type variable representing the type of this variable.
pub fn get_or_create_typevar(&mut self) -> TypeVar {
match &self.type_var {
Some(tv) => tv.clone(),
None => {
// Create a new type var in which we allow all types.
let tv = TypeVar::new(
format!("typeof_{}", self.name),
format!("Type of the pattern variable {:?}", self),
TypeSetBuilder::all(),
);
self.type_var = Some(tv.clone());
self.is_original_type_var = true;
tv
}
}
}
pub fn get_typevar(&self) -> Option<TypeVar> {
self.type_var.clone()
}
pub fn set_typevar(&mut self, tv: TypeVar) {
self.is_original_type_var = if let Some(previous_tv) = &self.type_var {
*previous_tv == tv
} else {
false
};
self.type_var = Some(tv);
}
/// Check if this variable has a free type variable. If not, the type of this variable is
/// computed from the type of another variable.
pub fn has_free_typevar(&self) -> bool {
match &self.type_var {
Some(tv) => tv.base.is_none() && self.is_original_type_var,
None => false,
}
}
pub fn to_rust_code(&self) -> String {
self.name.into()
}
fn rust_type(&self) -> String {
self.type_var.as_ref().unwrap().to_rust_code()
}
}
impl fmt::Debug for Var {
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
fmt.write_fmt(format_args!(
"Var({}{}{})",
self.name,
if self.src_def.is_some() { ", src" } else { "" },
if self.dst_def.is_some() { ", dst" } else { "" }
))
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct VarIndex(u32);
entity_impl!(VarIndex);
pub struct VarPool {
pool: PrimaryMap<VarIndex, Var>,
}
impl VarPool {
pub fn new() -> Self {
Self {
pool: PrimaryMap::new(),
}
}
pub fn get(&self, index: VarIndex) -> &Var {
self.pool.get(index).unwrap()
}
pub fn get_mut(&mut self, index: VarIndex) -> &mut Var {
self.pool.get_mut(index).unwrap()
}
pub fn create(&mut self, name: &'static str) -> VarIndex {
self.pool.push(Var::new(name))
}
}
/// Apply an instruction to arguments.
///
/// An `Apply` AST expression is created by using function call syntax on instructions. This
/// applies to both bound and unbound polymorphic instructions.
pub struct Apply {
pub inst: Instruction,
pub args: Vec<Expr>,
pub value_types: Vec<ValueType>,
}
impl Apply {
pub fn new(target: InstSpec, args: Vec<Expr>) -> Self {
let (inst, value_types) = match target.into() {
InstSpec::Inst(inst) => (inst, Vec::new()),
InstSpec::Bound(bound_inst) => (bound_inst.inst, bound_inst.value_types),
};
// Basic check on number of arguments.
assert!(
inst.operands_in.len() == args.len(),
format!("incorrect number of arguments in instruction {}", inst.name)
);
// Check that the kinds of Literals arguments match the expected operand.
for &imm_index in &inst.imm_opnums {
let arg = &args[imm_index];
if let Some(literal) = arg.maybe_literal() {
let op = &inst.operands_in[imm_index];
assert!(
op.kind.name == literal.kind.name,
format!(
"Passing literal of kind {} to field of wrong kind {}",
literal.kind.name, op.kind.name
)
);
}
}
Self {
inst,
args,
value_types,
}
}
fn to_comment_string(&self, var_pool: &VarPool) -> String {
let args = self
.args
.iter()
.map(|arg| arg.to_rust_code(var_pool))
.collect::<Vec<_>>()
.join(", ");
let mut inst_and_bound_types = vec![self.inst.name.to_string()];
inst_and_bound_types.extend(self.value_types.iter().map(|vt| vt.to_string()));
let inst_name = inst_and_bound_types.join(".");
format!("{}({})", inst_name, args)
}
fn to_rust_code(&self, var_pool: &VarPool) -> String {
let args = self
.args
.iter()
.map(|arg| arg.to_rust_code(var_pool))
.collect::<Vec<_>>()
.join(", ");
format!("{}({})", self.inst.name, args)
}
fn inst_predicate(
&self,
format_registry: &FormatRegistry,
var_pool: &VarPool,
) -> InstructionPredicate {
let iform = format_registry.get(self.inst.format);
let mut pred = InstructionPredicate::new();
for (format_field, &op_num) in iform.imm_fields.iter().zip(self.inst.imm_opnums.iter()) {
let arg = &self.args[op_num];
if arg.maybe_var().is_some() {
// Ignore free variables for now.
continue;
}
pred = pred.and(InstructionPredicate::new_is_field_equal(
&format_field,
arg.to_rust_code(var_pool),
));
}
// Add checks for any bound secondary type variables. We can't check the controlling type
// variable this way since it may not appear as the type of an operand.
if self.value_types.len() > 1 {
let poly = self
.inst
.polymorphic_info
.as_ref()
.expect("must have polymorphic info if it has bounded types");
for (bound_type, type_var) in
self.value_types[1..].iter().zip(poly.other_typevars.iter())
{
pred = pred.and(InstructionPredicate::new_typevar_check(
&self.inst, type_var, bound_type,
));
}
}
pred
}
/// Same as `inst_predicate()`, but also check the controlling type variable.
pub fn inst_predicate_with_ctrl_typevar(
&self,
format_registry: &FormatRegistry,
var_pool: &VarPool,
) -> InstructionPredicate {
let mut pred = self.inst_predicate(format_registry, var_pool);
if !self.value_types.is_empty() {
let bound_type = &self.value_types[0];
let poly = self.inst.polymorphic_info.as_ref().unwrap();
let type_check = if poly.use_typevar_operand {
InstructionPredicate::new_typevar_check(&self.inst, &poly.ctrl_typevar, bound_type)
} else {
InstructionPredicate::new_ctrl_typevar_check(&bound_type)
};
pred = pred.and(type_check);
}
pred
}
pub fn rust_builder(&self, defined_vars: &Vec<VarIndex>, var_pool: &VarPool) -> String {
let mut args = self
.args
.iter()
.map(|expr| expr.to_rust_code(var_pool))
.collect::<Vec<_>>()
.join(", ");
// Do we need to pass an explicit type argument?
if let Some(poly) = &self.inst.polymorphic_info {
if !poly.use_typevar_operand {
args = format!("{}, {}", var_pool.get(defined_vars[0]).rust_type(), args);
}
}
format!("{}({})", self.inst.snake_name(), args)
}
}
// Simple helpers for legalize actions construction.
pub enum DummyExpr {
Var(DummyVar),
Literal(Literal),
Apply(InstSpec, Vec<DummyExpr>),
}
#[derive(Clone)]
pub struct DummyVar {
pub name: &'static str,
}
impl Into<DummyExpr> for DummyVar {
fn into(self) -> DummyExpr {
DummyExpr::Var(self)
}
}
impl Into<DummyExpr> for Literal {
fn into(self) -> DummyExpr {
DummyExpr::Literal(self)
}
}
pub fn var(name: &'static str) -> DummyVar {
DummyVar { name }
}
pub struct DummyDef {
pub expr: DummyExpr,
pub defined_vars: Vec<DummyVar>,
}
pub struct ExprBuilder {
expr: DummyExpr,
}
impl ExprBuilder {
pub fn apply(inst: InstSpec, args: Vec<DummyExpr>) -> Self {
let expr = DummyExpr::Apply(inst, args);
Self { expr }
}
pub fn assign_to(self, defined_vars: Vec<DummyVar>) -> DummyDef {
DummyDef {
expr: self.expr,
defined_vars,
}
}
}
macro_rules! def_rhs {
// inst(a, b, c)
($inst:ident($($src:expr),*)) => {
ExprBuilder::apply($inst.into(), vec![$($src.clone().into()),*])
};
// inst.type(a, b, c)
($inst:ident.$type:ident($($src:expr),*)) => {
ExprBuilder::apply(bind($inst, $type).into(), vec![$($src.clone().into()),*])
};
}
// Helper macro to define legalization recipes.
macro_rules! def {
// x = ...
($dest:ident = $($tt:tt)*) => {
def_rhs!($($tt)*).assign_to(vec![$dest.clone()])
};
// (x, y, ...) = ...
(($($dest:ident),*) = $($tt:tt)*) => {
def_rhs!($($tt)*).assign_to(vec![$($dest.clone()),*])
};
// An instruction with no results.
($($tt:tt)*) => {
def_rhs!($($tt)*).assign_to(Vec::new())
}
}