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roc/compiler/mono/src/layout.rs
Folkert 1a39fa201c dicts are only 3 words on the stack
2021-02-20 04:16:09 +01:00

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use crate::ir::Parens;
use bumpalo::collections::Vec;
use bumpalo::Bump;
use roc_collections::all::{default_hasher, MutMap, MutSet};
use roc_module::ident::{Lowercase, TagName};
use roc_module::symbol::{Interns, Symbol};
use roc_types::subs::{Content, FlatType, Subs, Variable};
use roc_types::types::RecordField;
use std::collections::HashMap;
use ven_pretty::{DocAllocator, DocBuilder};
pub const MAX_ENUM_SIZE: usize = (std::mem::size_of::<u8>() * 8) as usize;
const GENERATE_NULLABLE: bool = true;
/// If a (Num *) gets translated to a Layout, this is the numeric type it defaults to.
const DEFAULT_NUM_BUILTIN: Builtin<'_> = Builtin::Int64;
pub const TAG_SIZE: Builtin<'_> = Builtin::Int64;
#[derive(Debug, Clone)]
pub enum LayoutProblem {
UnresolvedTypeVar(Variable),
Erroneous,
}
/// Types for code gen must be monomorphic. No type variables allowed!
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum Layout<'a> {
Builtin(Builtin<'a>),
/// A layout that is empty (turns into the empty struct in LLVM IR
/// but for our purposes, not zero-sized, so it does not get dropped from data structures
/// this is important for closures that capture zero-sized values
PhantomEmptyStruct,
Struct(&'a [Layout<'a>]),
Union(UnionLayout<'a>),
RecursivePointer,
/// A function. The types of its arguments, then the type of its return value.
FunctionPointer(&'a [Layout<'a>], &'a Layout<'a>),
Closure(&'a [Layout<'a>], ClosureLayout<'a>, &'a Layout<'a>),
Pointer(&'a Layout<'a>),
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum UnionLayout<'a> {
/// A non-recursive tag union
/// e.g. `Result a e : [ Ok a, Err e ]`
NonRecursive(&'a [&'a [Layout<'a>]]),
/// A recursive tag union
/// e.g. `Expr : [ Sym Str, Add Expr Expr ]`
Recursive(&'a [&'a [Layout<'a>]]),
/// A recursive tag union with just one constructor
/// e.g. `RoseTree a : [ Tree a (List (RoseTree a)) ]`
NonNullableUnwrapped(&'a [Layout<'a>]),
/// A recursive tag union where the non-nullable variant(s) store the tag id
/// e.g. `FingerTree a : [ Empty, Single a, More (Some a) (FingerTree (Tuple a)) (Some a) ]`
/// see also: https://youtu.be/ip92VMpf_-A?t=164
NullableWrapped {
nullable_id: i64,
other_tags: &'a [&'a [Layout<'a>]],
},
/// A recursive tag union where the non-nullable variant does NOT store the tag id
/// e.g. `ConsList a : [ Nil, Cons a (ConsList a) ]`
NullableUnwrapped {
nullable_id: bool,
other_fields: &'a [Layout<'a>],
},
}
impl<'a> UnionLayout<'a> {
pub fn to_doc<'b, D, A>(&'b self, alloc: &'b D, _parens: Parens) -> DocBuilder<'b, D, A>
where
D: DocAllocator<'b, A>,
D::Doc: Clone,
A: Clone,
{
use UnionLayout::*;
match self {
NonRecursive(tags) => {
let tags_doc = tags.iter().map(|fields| {
alloc.text("C ").append(alloc.intersperse(
fields.iter().map(|x| x.to_doc(alloc, Parens::InTypeParam)),
" ",
))
});
alloc
.text("[")
.append(alloc.intersperse(tags_doc, ", "))
.append(alloc.text("]"))
}
_ => alloc.text("TODO"),
}
}
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct ClosureLayout<'a> {
/// the layout that this specific closure captures
/// uses a Vec instead of a MutMap because it's Hash
/// the vec is likely to be small, so linear search is fine
captured: &'a [(TagName, &'a [Layout<'a>])],
/// use with care; there is some stuff happening here re. unwrapping
/// one-element records that might cause issues
pub layout: &'a Layout<'a>,
}
impl<'a> ClosureLayout<'a> {
fn from_unit(arena: &'a Bump) -> Self {
let layout = Layout::PhantomEmptyStruct;
let layouts = arena.alloc(layout);
ClosureLayout {
captured: &[],
layout: layouts,
}
}
fn from_bool(arena: &'a Bump) -> Self {
let layout = Layout::Builtin(Builtin::Int1);
let layouts = arena.alloc(layout);
ClosureLayout {
captured: &[],
layout: layouts,
}
}
fn from_byte(arena: &'a Bump) -> Self {
let layout = Layout::Builtin(Builtin::Int8);
let layouts = arena.alloc(layout);
ClosureLayout {
captured: &[],
layout: layouts,
}
}
fn from_unwrapped(arena: &'a Bump, layouts: &'a [Layout<'a>]) -> Self {
debug_assert!(!layouts.is_empty());
// DO NOT unwrap 1-element records here!
let layout = arena.alloc(Layout::Struct(layouts));
ClosureLayout {
captured: &[],
layout,
}
}
fn from_tag_union(arena: &'a Bump, tags: &'a [(TagName, &'a [Layout<'a>])]) -> Self {
debug_assert!(tags.len() > 1);
// if the closed-over value is actually a layout, it should be wrapped in a 1-element record
debug_assert!(matches!(tags[0].0, TagName::Closure(_)));
let mut tag_arguments = Vec::with_capacity_in(tags.len(), arena);
for (_, tag_args) in tags.iter() {
tag_arguments.push(&tag_args[0..]);
}
ClosureLayout {
captured: tags,
layout: arena.alloc(Layout::Union(UnionLayout::NonRecursive(
tag_arguments.into_bump_slice(),
))),
}
}
pub fn get_wrapped(&self) -> crate::ir::Wrapped {
use crate::ir::Wrapped;
match self.layout {
Layout::Struct(fields) if fields.len() == 1 => Wrapped::SingleElementRecord,
Layout::Struct(_) => Wrapped::RecordOrSingleTagUnion,
Layout::Union(_) => Wrapped::MultiTagUnion,
_ => Wrapped::SingleElementRecord,
}
}
pub fn from_var(
arena: &'a Bump,
subs: &Subs,
closure_var: Variable,
) -> Result<Option<Self>, LayoutProblem> {
let mut tags = std::vec::Vec::new();
match roc_types::pretty_print::chase_ext_tag_union(subs, closure_var, &mut tags) {
Ok(()) | Err((_, Content::FlexVar(_))) if !tags.is_empty() => {
// special-case the `[ Closure1, Closure2, Closure3 ]` case, where none of
// the tags have a payload
let all_no_payload = tags.iter().all(|(_, arguments)| arguments.is_empty());
if all_no_payload {
return Ok(None);
}
// otherwise, this is a closure with a payload
let variant = union_sorted_tags_help(arena, tags, None, subs);
use UnionVariant::*;
match variant {
Never => Ok(None),
Unit => Ok(None),
UnitWithArguments => {
// the closure layout is zero-sized, but there is something in it (e.g. `{}`)
let closure_layout = ClosureLayout::from_unit(arena);
Ok(Some(closure_layout))
}
BoolUnion { .. } => {
let closure_layout = ClosureLayout::from_bool(arena);
Ok(Some(closure_layout))
}
ByteUnion(_) => {
let closure_layout = ClosureLayout::from_byte(arena);
Ok(Some(closure_layout))
}
Unwrapped(layouts) => {
let closure_layout =
ClosureLayout::from_unwrapped(arena, layouts.into_bump_slice());
Ok(Some(closure_layout))
}
Wrapped(variant) => {
use WrappedVariant::*;
match variant {
NonRecursive {
sorted_tag_layouts: tags,
} => {
let closure_layout =
ClosureLayout::from_tag_union(arena, tags.into_bump_slice());
Ok(Some(closure_layout))
}
_ => panic!("handle recursive layouts"),
}
}
}
}
Ok(()) | Err((_, Content::FlexVar(_))) => {
// a max closure size of 0 means this is a standart top-level function
Ok(None)
}
_ => panic!("called ClosureLayout.from_var on invalid input"),
}
}
pub fn extend_function_layout(
arena: &'a Bump,
argument_layouts: &'a [Layout<'a>],
closure_layout: Self,
ret_layout: &'a Layout<'a>,
) -> Layout<'a> {
let closure_data_layout = match closure_layout.layout {
Layout::Struct(fields) if fields.len() == 1 => &fields[0],
other => other,
};
// define the function pointer
let function_ptr_layout = {
let mut temp = Vec::from_iter_in(argument_layouts.iter().cloned(), arena);
temp.push(closure_data_layout.clone());
Layout::FunctionPointer(temp.into_bump_slice(), ret_layout)
};
function_ptr_layout
}
pub fn stack_size(&self, pointer_size: u32) -> u32 {
self.layout.stack_size(pointer_size)
}
pub fn contains_refcounted(&self) -> bool {
self.layout.contains_refcounted()
}
pub fn safe_to_memcpy(&self) -> bool {
self.layout.safe_to_memcpy()
}
pub fn as_named_layout(&self, symbol: Symbol) -> Layout<'a> {
let layouts = if self.captured.is_empty() {
match self.layout {
Layout::Struct(fields) if fields.len() == 1 => fields[0].clone(),
other => other.clone(),
}
} else if let Some((_, tag_args)) = self
.captured
.iter()
.find(|(tn, _)| *tn == TagName::Closure(symbol))
{
if tag_args.len() == 1 {
tag_args[0].clone()
} else {
Layout::Struct(tag_args)
}
} else {
unreachable!(
"invariant broken, TagName::Closure({:?}) is not in {:?}",
symbol, &self.captured
);
};
layouts
}
pub fn as_block_of_memory_layout(&self) -> Layout<'a> {
match self.layout {
Layout::Struct(fields) if fields.len() == 1 => fields[0].clone(),
other => other.clone(),
}
}
pub fn internal_layout(&self) -> Layout<'a> {
self.layout.clone()
}
pub fn build_closure_data(
&self,
original: Symbol,
symbols: &'a [Symbol],
) -> BuildClosureData<'a> {
use crate::ir::Expr;
match self.layout {
Layout::Struct(fields) if fields.len() == 1 => BuildClosureData::Alias(symbols[0]),
Layout::Struct(fields) => {
debug_assert!(fields.len() > 1);
debug_assert_eq!(fields.len(), symbols.len());
BuildClosureData::Struct(Expr::Struct(symbols))
}
Layout::Union(UnionLayout::NonRecursive(tags)) => {
// NOTE it's very important that this Union consists of Closure tags
// and is not an unpacked 1-element record
let tag_id = self
.captured
.iter()
.position(|(tn, _)| *tn == TagName::Closure(original))
.unwrap() as _;
BuildClosureData::Union {
tag_layout: Layout::Union(UnionLayout::NonRecursive(tags)),
tag_name: TagName::Closure(original),
tag_id,
union_size: tags.len() as u8,
}
}
Layout::PhantomEmptyStruct => {
debug_assert_eq!(symbols.len(), 1);
BuildClosureData::Struct(Expr::Struct(&[]))
}
_ => {
debug_assert_eq!(
symbols.len(),
1,
"symbols {:?} for layout {:?}",
&symbols,
&self.layout
);
BuildClosureData::Alias(symbols[0])
}
}
}
}
pub enum BuildClosureData<'a> {
Alias(Symbol),
Struct(crate::ir::Expr<'a>),
Union {
tag_layout: Layout<'a>,
tag_name: TagName,
tag_id: u8,
union_size: u8,
},
}
#[derive(Clone, Debug, PartialEq, Eq, Hash, Copy)]
pub enum MemoryMode {
Unique,
Refcounted,
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum Builtin<'a> {
Int128,
Int64,
Int32,
Int16,
Int8,
Int1,
Usize,
Float128,
Float64,
Float32,
Float16,
Str,
Dict(&'a Layout<'a>, &'a Layout<'a>),
Set(&'a Layout<'a>),
List(MemoryMode, &'a Layout<'a>),
EmptyStr,
EmptyList,
EmptyDict,
EmptySet,
}
pub struct Env<'a, 'b> {
arena: &'a Bump,
seen: MutSet<Variable>,
subs: &'b Subs,
}
impl<'a, 'b> Env<'a, 'b> {
fn is_seen(&self, var: Variable) -> bool {
let var = self.subs.get_root_key_without_compacting(var);
self.seen.contains(&var)
}
fn insert_seen(&mut self, var: Variable) -> bool {
let var = self.subs.get_root_key_without_compacting(var);
self.seen.insert(var)
}
}
impl<'a> Layout<'a> {
fn new_help<'b>(
env: &mut Env<'a, 'b>,
var: Variable,
content: Content,
) -> Result<Self, LayoutProblem> {
use roc_types::subs::Content::*;
match content {
FlexVar(_) | RigidVar(_) => Err(LayoutProblem::UnresolvedTypeVar(var)),
RecursionVar { structure, .. } => {
let structure_content = env.subs.get_without_compacting(structure).content;
Self::new_help(env, structure, structure_content)
}
Structure(flat_type) => layout_from_flat_type(env, flat_type),
// Ints
Alias(Symbol::NUM_I128, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int128))
}
Alias(Symbol::NUM_I64, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int64))
}
Alias(Symbol::NUM_I32, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int32))
}
Alias(Symbol::NUM_I16, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int16))
}
Alias(Symbol::NUM_I8, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int8))
}
// I think unsigned and signed use the same layout
Alias(Symbol::NUM_U128, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int128))
}
Alias(Symbol::NUM_U64, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int64))
}
Alias(Symbol::NUM_U32, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int32))
}
Alias(Symbol::NUM_U16, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int16))
}
Alias(Symbol::NUM_U8, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Int8))
}
// Floats
Alias(Symbol::NUM_F64, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Float64))
}
Alias(Symbol::NUM_F32, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Float32))
}
Alias(_, _, var) => Self::from_var(env, var),
Error => Err(LayoutProblem::Erroneous),
}
}
/// Returns Err(()) if given an error, or Ok(Layout) if given a non-erroneous Structure.
/// Panics if given a FlexVar or RigidVar, since those should have been
/// monomorphized away already!
fn from_var(env: &mut Env<'a, '_>, var: Variable) -> Result<Self, LayoutProblem> {
if env.is_seen(var) {
Ok(Layout::RecursivePointer)
} else {
let content = env.subs.get_without_compacting(var).content;
Self::new_help(env, var, content)
}
}
pub fn safe_to_memcpy(&self) -> bool {
use Layout::*;
match self {
Builtin(builtin) => builtin.safe_to_memcpy(),
PhantomEmptyStruct => true,
Struct(fields) => fields
.iter()
.all(|field_layout| field_layout.safe_to_memcpy()),
Union(variant) => {
use UnionLayout::*;
match variant {
NonRecursive(tags) => tags
.iter()
.all(|tag_layout| tag_layout.iter().all(|field| field.safe_to_memcpy())),
Recursive(_)
| NullableWrapped { .. }
| NullableUnwrapped { .. }
| NonNullableUnwrapped(_) => {
// a recursive union will always contain a pointer, and is thus not safe to memcpy
false
}
}
}
FunctionPointer(_, _) => {
// Function pointers are immutable and can always be safely copied
true
}
Closure(_, closure_layout, _) => closure_layout.safe_to_memcpy(),
Pointer(_) => {
// We cannot memcpy pointers, because then we would have the same pointer in multiple places!
false
}
RecursivePointer => {
// We cannot memcpy pointers, because then we would have the same pointer in multiple places!
false
}
}
}
pub fn is_dropped_because_empty(&self) -> bool {
// For this calculation, we don't need an accurate
// stack size, we just need to know whether it's zero,
// so it's fine to use a pointer size of 1.
if let Layout::PhantomEmptyStruct = self {
false
} else {
// self.stack_size(1) == 0
false
}
}
pub fn stack_size(&self, pointer_size: u32) -> u32 {
use Layout::*;
match self {
Builtin(builtin) => builtin.stack_size(pointer_size),
PhantomEmptyStruct => 0,
Struct(fields) => {
let mut sum = 0;
for field_layout in *fields {
sum += field_layout.stack_size(pointer_size);
}
sum
}
Union(variant) => {
use UnionLayout::*;
match variant {
NonRecursive(fields) => fields
.iter()
.map(|tag_layout| {
tag_layout
.iter()
.map(|field| field.stack_size(pointer_size))
.sum()
})
.max()
.unwrap_or_default(),
Recursive(_)
| NullableWrapped { .. }
| NullableUnwrapped { .. }
| NonNullableUnwrapped(_) => pointer_size,
}
}
Closure(_, closure_layout, _) => pointer_size + closure_layout.stack_size(pointer_size),
FunctionPointer(_, _) => pointer_size,
RecursivePointer => pointer_size,
Pointer(_) => pointer_size,
}
}
pub fn alignment_bytes(&self, pointer_size: u32) -> u32 {
match self {
Layout::Struct(fields) => fields
.iter()
.map(|x| x.alignment_bytes(pointer_size))
.max()
.unwrap_or(0),
Layout::Union(variant) => {
use UnionLayout::*;
match variant {
NonRecursive(tags) => tags
.iter()
.map(|x| x.iter())
.flatten()
.map(|x| x.alignment_bytes(pointer_size))
.max()
.unwrap_or(0),
Recursive(_)
| NullableWrapped { .. }
| NullableUnwrapped { .. }
| NonNullableUnwrapped(_) => pointer_size,
}
}
Layout::Builtin(builtin) => builtin.alignment_bytes(pointer_size),
Layout::PhantomEmptyStruct => 0,
Layout::RecursivePointer => pointer_size,
Layout::FunctionPointer(_, _) => pointer_size,
Layout::Pointer(_) => pointer_size,
Layout::Closure(_, captured, _) => {
pointer_size.max(captured.layout.alignment_bytes(pointer_size))
}
}
}
pub fn is_refcounted(&self) -> bool {
use self::Builtin::*;
use Layout::*;
match self {
Union(variant) => {
use UnionLayout::*;
matches!(variant, Recursive(_)| NullableWrapped { .. } | NullableUnwrapped { .. })
}
RecursivePointer => true,
Builtin(List(MemoryMode::Refcounted, _)) | Builtin(Str) => true,
_ => false,
}
}
/// Even if a value (say, a record) is not itself reference counted,
/// it may contains values/fields that are. Therefore when this record
/// goes out of scope, the refcount on those values/fields must be decremented.
pub fn contains_refcounted(&self) -> bool {
use Layout::*;
match self {
Builtin(builtin) => builtin.is_refcounted(),
PhantomEmptyStruct => false,
Struct(fields) => fields.iter().any(|f| f.contains_refcounted()),
Union(variant) => {
use UnionLayout::*;
match variant {
NonRecursive(fields) => fields
.iter()
.map(|ls| ls.iter())
.flatten()
.any(|f| f.contains_refcounted()),
Recursive(_)
| NullableWrapped { .. }
| NullableUnwrapped { .. }
| NonNullableUnwrapped(_) => true,
}
}
RecursivePointer => true,
Closure(_, closure_layout, _) => closure_layout.contains_refcounted(),
FunctionPointer(_, _) | Pointer(_) => false,
}
}
pub fn to_doc<'b, D, A>(&'b self, alloc: &'b D, parens: Parens) -> DocBuilder<'b, D, A>
where
D: DocAllocator<'b, A>,
D::Doc: Clone,
A: Clone,
{
use Layout::*;
match self {
Builtin(builtin) => builtin.to_doc(alloc, parens),
PhantomEmptyStruct => alloc.text("{}"),
Struct(fields) => {
let fields_doc = fields.iter().map(|x| x.to_doc(alloc, parens));
alloc
.text("{")
.append(alloc.intersperse(fields_doc, ", "))
.append(alloc.text("}"))
}
Union(union_layout) => union_layout.to_doc(alloc, parens),
RecursivePointer => alloc.text("*self"),
FunctionPointer(args, result) => {
let args_doc = args.iter().map(|x| x.to_doc(alloc, Parens::InFunction));
alloc
.intersperse(args_doc, ", ")
.append(alloc.text(" -> "))
.append(result.to_doc(alloc, Parens::InFunction))
}
Closure(args, closure_layout, result) => {
let args_doc = args.iter().map(|x| x.to_doc(alloc, Parens::InFunction));
let bom = closure_layout.layout.to_doc(alloc, Parens::NotNeeded);
alloc
.intersperse(args_doc, ", ")
.append(alloc.text(" {| "))
.append(bom)
.append(" |} -> ")
.append(result.to_doc(alloc, Parens::InFunction))
}
Pointer(_) => todo!(),
}
}
}
/// Avoid recomputing Layout from Variable multiple times.
/// We use `ena` for easy snapshots and rollbacks of the cache.
/// During specialization, a type variable `a` can be specialized to different layouts,
/// e.g. `identity : a -> a` could be specialized to `Bool -> Bool` or `Str -> Str`.
/// Therefore in general it's invalid to store a map from variables to layouts
/// But if we're careful when to invalidate certain keys, we still get some benefit
#[derive(Default, Debug)]
pub struct LayoutCache<'a> {
layouts: ven_ena::unify::UnificationTable<ven_ena::unify::InPlace<CachedVariable<'a>>>,
}
#[derive(Debug, Clone)]
pub enum CachedLayout<'a> {
Cached(Layout<'a>),
NotCached,
Problem(LayoutProblem),
}
/// Must wrap so we can define a specific UnifyKey instance
/// PhantomData so we can store the 'a lifetime, which is needed to implement the UnifyKey trait,
/// specifically so we can use `type Value = CachedLayout<'a>`
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct CachedVariable<'a>(Variable, std::marker::PhantomData<&'a ()>);
impl<'a> CachedVariable<'a> {
fn new(var: Variable) -> Self {
CachedVariable(var, std::marker::PhantomData)
}
}
// use ven_ena::unify::{InPlace, Snapshot, UnificationTable, UnifyKey};
impl<'a> ven_ena::unify::UnifyKey for CachedVariable<'a> {
type Value = CachedLayout<'a>;
fn index(&self) -> u32 {
self.0.index()
}
fn from_index(index: u32) -> Self {
CachedVariable(Variable::from_index(index), std::marker::PhantomData)
}
fn tag() -> &'static str {
"CachedVariable"
}
}
impl<'a> LayoutCache<'a> {
/// Returns Err(()) if given an error, or Ok(Layout) if given a non-erroneous Structure.
/// Panics if given a FlexVar or RigidVar, since those should have been
/// monomorphized away already!
pub fn from_var(
&mut self,
arena: &'a Bump,
var: Variable,
subs: &Subs,
) -> Result<Layout<'a>, LayoutProblem> {
// Store things according to the root Variable, to avoid duplicate work.
let var = subs.get_root_key_without_compacting(var);
let cached_var = CachedVariable::new(var);
self.expand_to_fit(cached_var);
use CachedLayout::*;
match self.layouts.probe_value(cached_var) {
Cached(result) => Ok(result),
Problem(problem) => Err(problem),
NotCached => {
let mut env = Env {
arena,
subs,
seen: MutSet::default(),
};
let result = Layout::from_var(&mut env, var);
// Don't actually cache. The layout cache is very hard to get right in the presence
// of specialization, it's turned of for now so an invalid cache is never the cause
// of a problem
if false {
let cached_layout = match &result {
Ok(layout) => Cached(layout.clone()),
Err(problem) => Problem(problem.clone()),
};
self.layouts
.update_value(cached_var, |existing| existing.value = cached_layout);
}
result
}
}
}
fn expand_to_fit(&mut self, var: CachedVariable<'a>) {
use ven_ena::unify::UnifyKey;
let required = (var.index() as isize) - (self.layouts.len() as isize) + 1;
if required > 0 {
self.layouts.reserve(required as usize);
for _ in 0..required {
self.layouts.new_key(CachedLayout::NotCached);
}
}
}
pub fn snapshot(
&mut self,
) -> ven_ena::unify::Snapshot<ven_ena::unify::InPlace<CachedVariable<'a>>> {
self.layouts.snapshot()
}
pub fn rollback_to(
&mut self,
snapshot: ven_ena::unify::Snapshot<ven_ena::unify::InPlace<CachedVariable<'a>>>,
) {
self.layouts.rollback_to(snapshot)
}
}
impl<'a> Builtin<'a> {
const I128_SIZE: u32 = std::mem::size_of::<i128>() as u32;
const I64_SIZE: u32 = std::mem::size_of::<i64>() as u32;
const I32_SIZE: u32 = std::mem::size_of::<i32>() as u32;
const I16_SIZE: u32 = std::mem::size_of::<i16>() as u32;
const I8_SIZE: u32 = std::mem::size_of::<i8>() as u32;
const I1_SIZE: u32 = std::mem::size_of::<bool>() as u32;
const USIZE_SIZE: u32 = std::mem::size_of::<usize>() as u32;
const F128_SIZE: u32 = 16;
const F64_SIZE: u32 = std::mem::size_of::<f64>() as u32;
const F32_SIZE: u32 = std::mem::size_of::<f32>() as u32;
const F16_SIZE: u32 = 2;
/// Number of machine words in an empty one of these
pub const STR_WORDS: u32 = 2;
pub const DICT_WORDS: u32 = 3;
pub const SET_WORDS: u32 = Builtin::DICT_WORDS; // Set is an alias for Dict with {} for value
pub const LIST_WORDS: u32 = 2;
/// Layout of collection wrapper for List and Str - a struct of (pointer, length).
///
/// We choose this layout (with pointer first) because it's how
/// Rust slices are laid out, meaning we can cast to/from them for free.
pub const WRAPPER_PTR: u32 = 0;
pub const WRAPPER_LEN: u32 = 1;
pub fn stack_size(&self, pointer_size: u32) -> u32 {
use Builtin::*;
match self {
Int128 => Builtin::I128_SIZE,
Int64 => Builtin::I64_SIZE,
Int32 => Builtin::I32_SIZE,
Int16 => Builtin::I16_SIZE,
Int8 => Builtin::I8_SIZE,
Int1 => Builtin::I1_SIZE,
Usize => Builtin::USIZE_SIZE,
Float128 => Builtin::F128_SIZE,
Float64 => Builtin::F64_SIZE,
Float32 => Builtin::F32_SIZE,
Float16 => Builtin::F16_SIZE,
Str | EmptyStr => Builtin::STR_WORDS * pointer_size,
Dict(_, _) | EmptyDict => Builtin::DICT_WORDS * pointer_size,
Set(_) | EmptySet => Builtin::SET_WORDS * pointer_size,
List(_, _) | EmptyList => Builtin::LIST_WORDS * pointer_size,
}
}
pub fn alignment_bytes(&self, pointer_size: u32) -> u32 {
use std::mem::align_of;
use Builtin::*;
// for our data structures, what counts is the alignment of the `( ptr, len )` tuple, and
// since both of those are one pointer size, the alignment of that structure is a pointer
// size
match self {
Int128 => align_of::<i128>() as u32,
Int64 => align_of::<i64>() as u32,
Int32 => align_of::<i32>() as u32,
Int16 => align_of::<i16>() as u32,
Int8 => align_of::<i8>() as u32,
Int1 => align_of::<bool>() as u32,
Usize => align_of::<usize>() as u32,
Float128 => align_of::<i128>() as u32,
Float64 => align_of::<f64>() as u32,
Float32 => align_of::<f32>() as u32,
Float16 => align_of::<i16>() as u32,
Str | EmptyStr => pointer_size,
Dict(_, _) | EmptyDict => pointer_size,
Set(_) | EmptySet => pointer_size,
List(_, _) | EmptyList => pointer_size,
}
}
pub fn safe_to_memcpy(&self) -> bool {
use Builtin::*;
match self {
Int128 | Int64 | Int32 | Int16 | Int8 | Int1 | Usize | Float128 | Float64 | Float32
| Float16 | EmptyStr | EmptyDict | EmptyList | EmptySet => true,
Str | Dict(_, _) | Set(_) | List(_, _) => false,
}
}
// Question: does is_refcounted exactly correspond with the "safe to memcpy" property?
pub fn is_refcounted(&self) -> bool {
use Builtin::*;
match self {
Int128 | Int64 | Int32 | Int16 | Int8 | Int1 | Usize | Float128 | Float64 | Float32
| Float16 | EmptyStr | EmptyDict | EmptyList | EmptySet => false,
List(mode, element_layout) => match mode {
MemoryMode::Refcounted => true,
MemoryMode::Unique => element_layout.contains_refcounted(),
},
Str | Dict(_, _) | Set(_) => true,
}
}
pub fn to_doc<'b, D, A>(&'b self, alloc: &'b D, _parens: Parens) -> DocBuilder<'b, D, A>
where
D: DocAllocator<'b, A>,
D::Doc: Clone,
A: Clone,
{
use Builtin::*;
match self {
Int128 => alloc.text("Int128"),
Int64 => alloc.text("Int64"),
Int32 => alloc.text("Int32"),
Int16 => alloc.text("Int16"),
Int8 => alloc.text("Int8"),
Int1 => alloc.text("Int1"),
Usize => alloc.text("Usize"),
Float128 => alloc.text("Float128"),
Float64 => alloc.text("Float64"),
Float32 => alloc.text("Float32"),
Float16 => alloc.text("Float16"),
EmptyStr => alloc.text("EmptyStr"),
EmptyList => alloc.text("EmptyList"),
EmptyDict => alloc.text("EmptyDict"),
EmptySet => alloc.text("EmptySet"),
Str => alloc.text("Str"),
List(_, layout) => alloc
.text("List ")
.append(layout.to_doc(alloc, Parens::InTypeParam)),
Set(layout) => alloc
.text("Set ")
.append(layout.to_doc(alloc, Parens::InTypeParam)),
Dict(key_layout, value_layout) => alloc
.text("Dict ")
.append(key_layout.to_doc(alloc, Parens::InTypeParam))
.append(" ")
.append(value_layout.to_doc(alloc, Parens::InTypeParam)),
}
}
}
fn layout_from_flat_type<'a>(
env: &mut Env<'a, '_>,
flat_type: FlatType,
) -> Result<Layout<'a>, LayoutProblem> {
use roc_types::subs::FlatType::*;
let arena = env.arena;
let subs = env.subs;
match flat_type {
Apply(symbol, args) => {
match symbol {
// Ints
Symbol::NUM_NAT => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Usize))
}
Symbol::NUM_I128 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int128))
}
Symbol::NUM_I64 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int64))
}
Symbol::NUM_I32 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int32))
}
Symbol::NUM_I16 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int16))
}
Symbol::NUM_I8 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int8))
}
Symbol::NUM_U128 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int128))
}
Symbol::NUM_U64 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int64))
}
Symbol::NUM_U32 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int32))
}
Symbol::NUM_U16 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int16))
}
Symbol::NUM_U8 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Int8))
}
// Floats
Symbol::NUM_F64 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Float64))
}
Symbol::NUM_F32 => {
debug_assert_eq!(args.len(), 0);
Ok(Layout::Builtin(Builtin::Float32))
}
Symbol::NUM_NUM | Symbol::NUM_AT_NUM => {
// Num.Num should only ever have 1 argument, e.g. Num.Num Int.Integer
debug_assert_eq!(args.len(), 1);
let var = args.first().unwrap();
let content = subs.get_without_compacting(*var).content;
layout_from_num_content(content)
}
Symbol::STR_STR => Ok(Layout::Builtin(Builtin::Str)),
Symbol::LIST_LIST => list_layout_from_elem(env, args[0]),
Symbol::DICT_DICT => dict_layout_from_key_value(env, args[0], args[1]),
Symbol::ATTR_ATTR => {
debug_assert_eq!(args.len(), 2);
// The first argument is the uniqueness info;
// second is the base type
let wrapped_var = args[1];
// correct the memory mode of unique lists
match Layout::from_var(env, wrapped_var)? {
Layout::Builtin(Builtin::List(_ignored, elem_layout)) => {
let uniqueness_var = args[0];
let uniqueness_content =
subs.get_without_compacting(uniqueness_var).content;
let mode = if uniqueness_content.is_unique(subs) {
MemoryMode::Unique
} else {
MemoryMode::Refcounted
};
Ok(Layout::Builtin(Builtin::List(mode, elem_layout)))
}
other => Ok(other),
}
}
Symbol::SET_SET => dict_layout_from_key_value(env, args[0], Variable::EMPTY_RECORD),
_ => {
panic!("TODO layout_from_flat_type for {:?}", Apply(symbol, args));
}
}
}
Func(args, closure_var, ret_var) => {
let mut fn_args = Vec::with_capacity_in(args.len(), arena);
for arg_var in args {
fn_args.push(Layout::from_var(env, arg_var)?);
}
let ret = Layout::from_var(env, ret_var)?;
let fn_args = fn_args.into_bump_slice();
let ret = arena.alloc(ret);
match ClosureLayout::from_var(env.arena, env.subs, closure_var)? {
Some(closure_layout) => Ok(Layout::Closure(fn_args, closure_layout, ret)),
None => Ok(Layout::FunctionPointer(fn_args, ret)),
}
}
Record(fields, ext_var) => {
// extract any values from the ext_var
let mut fields_map = MutMap::default();
fields_map.extend(fields);
match roc_types::pretty_print::chase_ext_record(subs, ext_var, &mut fields_map) {
Ok(()) | Err((_, Content::FlexVar(_))) => {}
Err(_) => unreachable!("this would have been a type error"),
}
let sorted_fields = sort_record_fields_help(env, fields_map);
// Determine the layouts of the fields, maintaining sort order
let mut layouts = Vec::with_capacity_in(sorted_fields.len(), arena);
for (_, _, res_layout) in sorted_fields {
match res_layout {
Ok(layout) => {
// Drop any zero-sized fields like {}.
if !layout.is_dropped_because_empty() {
layouts.push(layout);
}
}
Err(_) => {
// optional field, ignore
continue;
}
}
}
if layouts.len() == 1 {
// If the record has only one field that isn't zero-sized,
// unwrap it.
Ok(layouts.pop().unwrap())
} else {
Ok(Layout::Struct(layouts.into_bump_slice()))
}
}
TagUnion(tags, ext_var) => {
debug_assert!(ext_var_is_empty_tag_union(subs, ext_var));
Ok(layout_from_tag_union(arena, tags, subs))
}
RecursiveTagUnion(rec_var, tags, ext_var) => {
debug_assert!(ext_var_is_empty_tag_union(subs, ext_var));
// some observations
//
// * recursive tag unions are always recursive
// * therefore at least one tag has a pointer (non-zero sized) field
// * they must (to be instantiated) have 2 or more tags
//
// That means none of the optimizations for enums or single tag tag unions apply
let rec_var = subs.get_root_key_without_compacting(rec_var);
env.insert_seen(rec_var);
let mut tag_layouts = Vec::with_capacity_in(tags.len(), arena);
// VERY IMPORTANT: sort the tags
let mut tags_vec: std::vec::Vec<_> = tags.into_iter().collect();
tags_vec.sort();
let mut nullable = None;
if GENERATE_NULLABLE {
for (index, (_name, variables)) in tags_vec.iter().enumerate() {
if variables.is_empty() {
nullable = Some(index as i64);
break;
}
}
}
for (index, (_name, variables)) in tags_vec.into_iter().enumerate() {
if matches!(nullable, Some(i) if i == index as i64) {
// don't add the
continue;
}
let mut tag_layout = Vec::with_capacity_in(variables.len() + 1, arena);
// store the discriminant
tag_layout.push(Layout::Builtin(TAG_SIZE));
for var in variables {
// TODO does this cause problems with mutually recursive unions?
if rec_var == subs.get_root_key_without_compacting(var) {
tag_layout.push(Layout::RecursivePointer);
continue;
}
tag_layout.push(Layout::from_var(env, var)?);
}
tag_layout.sort_by(|layout1, layout2| {
let ptr_bytes = 8;
let size1 = layout1.alignment_bytes(ptr_bytes);
let size2 = layout2.alignment_bytes(ptr_bytes);
size2.cmp(&size1)
});
tag_layouts.push(tag_layout.into_bump_slice());
}
let union_layout = if let Some(tag_id) = nullable {
match tag_layouts.into_bump_slice() {
[one] => {
let nullable_id = tag_id != 0;
UnionLayout::NullableUnwrapped {
nullable_id,
other_fields: one,
}
}
many => UnionLayout::NullableWrapped {
nullable_id: tag_id,
other_tags: many,
},
}
} else if tag_layouts.len() == 1 {
// drop the tag id
UnionLayout::NonNullableUnwrapped(&tag_layouts.pop().unwrap()[1..])
} else {
UnionLayout::Recursive(tag_layouts.into_bump_slice())
};
Ok(Layout::Union(union_layout))
}
EmptyTagUnion => {
panic!("TODO make Layout for empty Tag Union");
}
Boolean(_) => {
panic!("TODO make Layout for Boolean");
}
Erroneous(_) => Err(LayoutProblem::Erroneous),
EmptyRecord => Ok(Layout::Struct(&[])),
}
}
pub fn sort_record_fields<'a>(
arena: &'a Bump,
var: Variable,
subs: &Subs,
) -> Vec<'a, (Lowercase, Variable, Result<Layout<'a>, Layout<'a>>)> {
let mut fields_map = MutMap::default();
let mut env = Env {
arena,
subs,
seen: MutSet::default(),
};
match roc_types::pretty_print::chase_ext_record(subs, var, &mut fields_map) {
Ok(()) | Err((_, Content::FlexVar(_))) => sort_record_fields_help(&mut env, fields_map),
Err(other) => panic!("invalid content in record variable: {:?}", other),
}
}
fn sort_record_fields_help<'a>(
env: &mut Env<'a, '_>,
fields_map: MutMap<Lowercase, RecordField<Variable>>,
) -> Vec<'a, (Lowercase, Variable, Result<Layout<'a>, Layout<'a>>)> {
// Sort the fields by label
let mut sorted_fields = Vec::with_capacity_in(fields_map.len(), env.arena);
for (label, field) in fields_map {
let var = match field {
RecordField::Demanded(v) => v,
RecordField::Required(v) => v,
RecordField::Optional(v) => {
let layout = Layout::from_var(env, v).expect("invalid layout from var");
sorted_fields.push((label, v, Err(layout)));
continue;
}
};
let layout = Layout::from_var(env, var).expect("invalid layout from var");
// Drop any zero-sized fields like {}
if !layout.is_dropped_because_empty() {
sorted_fields.push((label, var, Ok(layout)));
}
}
sorted_fields.sort_by(
|(label1, _, res_layout1), (label2, _, res_layout2)| match res_layout1 {
Ok(layout1) | Err(layout1) => match res_layout2 {
Ok(layout2) | Err(layout2) => {
let ptr_bytes = 8;
let size1 = layout1.alignment_bytes(ptr_bytes);
let size2 = layout2.alignment_bytes(ptr_bytes);
size2.cmp(&size1).then(label1.cmp(label2))
}
},
},
);
sorted_fields
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum UnionVariant<'a> {
Never,
Unit,
UnitWithArguments,
BoolUnion { ttrue: TagName, ffalse: TagName },
ByteUnion(Vec<'a, TagName>),
Unwrapped(Vec<'a, Layout<'a>>),
Wrapped(WrappedVariant<'a>),
}
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum WrappedVariant<'a> {
Recursive {
sorted_tag_layouts: Vec<'a, (TagName, &'a [Layout<'a>])>,
},
NonRecursive {
sorted_tag_layouts: Vec<'a, (TagName, &'a [Layout<'a>])>,
},
NullableWrapped {
nullable_id: i64,
nullable_name: TagName,
sorted_tag_layouts: Vec<'a, (TagName, &'a [Layout<'a>])>,
},
NonNullableUnwrapped {
tag_name: TagName,
fields: &'a [Layout<'a>],
},
NullableUnwrapped {
nullable_id: bool,
nullable_name: TagName,
other_name: TagName,
other_fields: &'a [Layout<'a>],
},
}
impl<'a> WrappedVariant<'a> {
pub fn tag_name_to_id(&self, tag_name: &TagName) -> (u8, &'a [Layout<'a>]) {
use WrappedVariant::*;
match self {
Recursive { sorted_tag_layouts } | NonRecursive { sorted_tag_layouts } => {
let (tag_id, (_, argument_layouts)) = sorted_tag_layouts
.iter()
.enumerate()
.find(|(_, (key, _))| key == tag_name)
.expect("tag name is not in its own type");
debug_assert!(tag_id < 256);
(tag_id as u8, *argument_layouts)
}
NullableWrapped {
nullable_id,
nullable_name,
sorted_tag_layouts,
} => {
// assumption: the nullable_name is not included in sorted_tag_layouts
if tag_name == nullable_name {
(*nullable_id as u8, &[] as &[_])
} else {
let (mut tag_id, (_, argument_layouts)) = sorted_tag_layouts
.iter()
.enumerate()
.find(|(_, (key, _))| key == tag_name)
.expect("tag name is not in its own type");
if tag_id >= *nullable_id as usize {
tag_id += 1;
}
debug_assert!(tag_id < 256);
(tag_id as u8, *argument_layouts)
}
}
NullableUnwrapped {
nullable_id,
nullable_name,
other_name,
other_fields,
} => {
if tag_name == nullable_name {
(*nullable_id as u8, &[] as &[_])
} else {
debug_assert_eq!(other_name, tag_name);
(!*nullable_id as u8, *other_fields)
}
}
NonNullableUnwrapped { fields, .. } => (0, fields),
}
}
pub fn number_of_tags(&'a self) -> usize {
use WrappedVariant::*;
match self {
Recursive { sorted_tag_layouts } | NonRecursive { sorted_tag_layouts } => {
sorted_tag_layouts.len()
}
NullableWrapped {
sorted_tag_layouts, ..
} => {
// assumption: the nullable_name is not included in sorted_tag_layouts
sorted_tag_layouts.len() + 1
}
NullableUnwrapped { .. } => 2,
NonNullableUnwrapped { .. } => 1,
}
}
}
pub fn union_sorted_tags<'a>(
arena: &'a Bump,
var: Variable,
subs: &Subs,
) -> Result<UnionVariant<'a>, LayoutProblem> {
let var =
if let Content::RecursionVar { structure, .. } = subs.get_without_compacting(var).content {
structure
} else {
var
};
let mut tags_vec = std::vec::Vec::new();
let result = match roc_types::pretty_print::chase_ext_tag_union(subs, var, &mut tags_vec) {
Ok(()) | Err((_, Content::FlexVar(_))) | Err((_, Content::RecursionVar { .. })) => {
let opt_rec_var = get_recursion_var(subs, var);
union_sorted_tags_help(arena, tags_vec, opt_rec_var, subs)
}
Err((_, Content::Error)) => return Err(LayoutProblem::Erroneous),
Err(other) => panic!("invalid content in tag union variable: {:?}", other),
};
Ok(result)
}
fn get_recursion_var(subs: &Subs, var: Variable) -> Option<Variable> {
match subs.get_without_compacting(var).content {
Content::Structure(FlatType::RecursiveTagUnion(rec_var, _, _)) => Some(rec_var),
Content::Structure(FlatType::Apply(Symbol::ATTR_ATTR, args)) => {
get_recursion_var(subs, args[1])
}
Content::Alias(_, _, actual) => get_recursion_var(subs, actual),
_ => None,
}
}
pub fn union_sorted_tags_help<'a>(
arena: &'a Bump,
mut tags_vec: std::vec::Vec<(TagName, std::vec::Vec<Variable>)>,
opt_rec_var: Option<Variable>,
subs: &Subs,
) -> UnionVariant<'a> {
// sort up front; make sure the ordering stays intact!
tags_vec.sort();
let mut env = Env {
arena,
subs,
seen: MutSet::default(),
};
if let Some(rec_var) = opt_rec_var {
env.insert_seen(rec_var);
}
match tags_vec.len() {
0 => {
// trying to instantiate a type with no values
UnionVariant::Never
}
1 => {
let (tag_name, arguments) = tags_vec.remove(0);
// just one tag in the union (but with arguments) can be a struct
let mut layouts = Vec::with_capacity_in(tags_vec.len(), arena);
let mut contains_zero_sized = false;
// special-case NUM_AT_NUM: if its argument is a FlexVar, make it Int
match tag_name {
TagName::Private(Symbol::NUM_AT_NUM) => {
layouts.push(unwrap_num_tag(subs, arguments[0]).expect("invalid num layout"));
}
_ => {
for var in arguments {
match Layout::from_var(&mut env, var) {
Ok(layout) => {
// Drop any zero-sized arguments like {}
if !layout.is_dropped_because_empty() {
layouts.push(layout);
} else {
contains_zero_sized = true;
}
}
Err(LayoutProblem::UnresolvedTypeVar(_)) => {
// If we encounter an unbound type var (e.g. `Ok *`)
// then it's zero-sized; drop the argument.
}
Err(LayoutProblem::Erroneous) => {
// An erroneous type var will code gen to a runtime
// error, so we don't need to store any data for it.
}
}
}
}
}
layouts.sort_by(|layout1, layout2| {
let ptr_bytes = 8;
let size1 = layout1.alignment_bytes(ptr_bytes);
let size2 = layout2.alignment_bytes(ptr_bytes);
size2.cmp(&size1)
});
if layouts.is_empty() {
if contains_zero_sized {
UnionVariant::UnitWithArguments
} else {
UnionVariant::Unit
}
} else if opt_rec_var.is_some() {
UnionVariant::Wrapped(WrappedVariant::NonNullableUnwrapped {
tag_name,
fields: layouts.into_bump_slice(),
})
} else {
UnionVariant::Unwrapped(layouts)
}
}
num_tags => {
// default path
let mut answer = Vec::with_capacity_in(tags_vec.len(), arena);
let mut has_any_arguments = false;
let mut nullable = None;
// only recursive tag unions can be nullable
let is_recursive = opt_rec_var.is_some();
if is_recursive && GENERATE_NULLABLE {
for (index, (name, variables)) in tags_vec.iter().enumerate() {
if variables.is_empty() {
nullable = Some((index as i64, name.clone()));
break;
}
}
}
for (index, (tag_name, arguments)) in tags_vec.into_iter().enumerate() {
// reserve space for the tag discriminant
if matches!(nullable, Some((i, _)) if i as usize == index) {
debug_assert!(arguments.is_empty());
continue;
}
let mut arg_layouts = Vec::with_capacity_in(arguments.len() + 1, arena);
// add the tag discriminant (size currently always hardcoded to i64)
arg_layouts.push(Layout::Builtin(TAG_SIZE));
for var in arguments {
match Layout::from_var(&mut env, var) {
Ok(layout) => {
// Drop any zero-sized arguments like {}
if !layout.is_dropped_because_empty() {
has_any_arguments = true;
arg_layouts.push(layout);
}
}
Err(LayoutProblem::UnresolvedTypeVar(_)) => {
// If we encounter an unbound type var (e.g. `Ok *`)
// then it's zero-sized; drop the argument.
}
Err(LayoutProblem::Erroneous) => {
// An erroneous type var will code gen to a runtime
// error, so we don't need to store any data for it.
}
}
}
arg_layouts.sort_by(|layout1, layout2| {
let ptr_bytes = 8;
let size1 = layout1.alignment_bytes(ptr_bytes);
let size2 = layout2.alignment_bytes(ptr_bytes);
size2.cmp(&size1)
});
answer.push((tag_name, arg_layouts.into_bump_slice()));
}
match num_tags {
2 if !has_any_arguments => {
// type can be stored in a boolean
// tags_vec is sorted, and answer is sorted the same way
let ttrue = answer.remove(1).0;
let ffalse = answer.remove(0).0;
UnionVariant::BoolUnion { ffalse, ttrue }
}
3..=MAX_ENUM_SIZE if !has_any_arguments => {
// type can be stored in a byte
// needs the sorted tag names to determine the tag_id
let mut tag_names = Vec::with_capacity_in(answer.len(), arena);
for (tag_name, _) in answer {
tag_names.push(tag_name);
}
UnionVariant::ByteUnion(tag_names)
}
_ => {
let variant = if let Some((nullable_id, nullable_name)) = nullable {
if answer.len() == 1 {
let (other_name, other_arguments) = answer.drain(..).next().unwrap();
let nullable_id = nullable_id != 0;
WrappedVariant::NullableUnwrapped {
nullable_id,
nullable_name,
other_name,
other_fields: other_arguments,
}
} else {
WrappedVariant::NullableWrapped {
nullable_id,
nullable_name,
sorted_tag_layouts: answer,
}
}
} else if is_recursive {
debug_assert!(answer.len() > 1);
WrappedVariant::Recursive {
sorted_tag_layouts: answer,
}
} else {
WrappedVariant::NonRecursive {
sorted_tag_layouts: answer,
}
};
UnionVariant::Wrapped(variant)
}
}
}
}
}
pub fn layout_from_tag_union<'a>(
arena: &'a Bump,
tags: MutMap<TagName, std::vec::Vec<Variable>>,
subs: &Subs,
) -> Layout<'a> {
use UnionVariant::*;
let tags_vec: std::vec::Vec<_> = tags.into_iter().collect();
match tags_vec.get(0) {
Some((tag_name, arguments)) if *tag_name == TagName::Private(Symbol::NUM_AT_NUM) => {
debug_assert_eq!(arguments.len(), 1);
let var = arguments.iter().next().unwrap();
unwrap_num_tag(subs, *var).expect("invalid Num argument")
}
_ => {
let opt_rec_var = None;
let variant = union_sorted_tags_help(arena, tags_vec, opt_rec_var, subs);
match variant {
Never => Layout::Union(UnionLayout::NonRecursive(&[])),
Unit | UnitWithArguments => Layout::Struct(&[]),
BoolUnion { .. } => Layout::Builtin(Builtin::Int1),
ByteUnion(_) => Layout::Builtin(Builtin::Int8),
Unwrapped(mut field_layouts) => {
if field_layouts.len() == 1 {
field_layouts.pop().unwrap()
} else {
Layout::Struct(field_layouts.into_bump_slice())
}
}
Wrapped(variant) => {
use WrappedVariant::*;
match variant {
NonRecursive {
sorted_tag_layouts: tags,
} => {
let mut tag_layouts = Vec::with_capacity_in(tags.len(), arena);
tag_layouts.extend(tags.iter().map(|r| r.1));
Layout::Union(UnionLayout::NonRecursive(tag_layouts.into_bump_slice()))
}
Recursive {
sorted_tag_layouts: tags,
} => {
let mut tag_layouts = Vec::with_capacity_in(tags.len(), arena);
tag_layouts.extend(tags.iter().map(|r| r.1));
debug_assert!(tag_layouts.len() > 1);
Layout::Union(UnionLayout::Recursive(tag_layouts.into_bump_slice()))
}
NullableWrapped {
nullable_id,
nullable_name: _,
sorted_tag_layouts: tags,
} => {
let mut tag_layouts = Vec::with_capacity_in(tags.len(), arena);
tag_layouts.extend(tags.iter().map(|r| r.1));
Layout::Union(UnionLayout::NullableWrapped {
nullable_id,
other_tags: tag_layouts.into_bump_slice(),
})
}
NullableUnwrapped { .. } => todo!(),
NonNullableUnwrapped { .. } => todo!(),
}
}
}
}
}
}
#[cfg(debug_assertions)]
fn ext_var_is_empty_tag_union(subs: &Subs, ext_var: Variable) -> bool {
// the ext_var is empty
let mut ext_fields = std::vec::Vec::new();
match roc_types::pretty_print::chase_ext_tag_union(subs, ext_var, &mut ext_fields) {
Ok(()) | Err((_, Content::FlexVar(_))) => ext_fields.is_empty(),
Err(content) => panic!("invalid content in ext_var: {:?}", content),
}
}
#[cfg(not(debug_assertions))]
fn ext_var_is_empty_tag_union(_: &Subs, _: Variable) -> bool {
// This should only ever be used in debug_assert! macros
unreachable!();
}
fn layout_from_num_content<'a>(content: Content) -> Result<Layout<'a>, LayoutProblem> {
use roc_types::subs::Content::*;
use roc_types::subs::FlatType::*;
match content {
RecursionVar { .. } => panic!("recursion var in num"),
FlexVar(_) | RigidVar(_) => {
// If a Num makes it all the way through type checking with an unbound
// type variable, then assume it's a 64-bit integer.
//
// (e.g. for (5 + 5) assume both 5s are 64-bit integers.)
Ok(Layout::Builtin(DEFAULT_NUM_BUILTIN))
}
Structure(Apply(symbol, args)) => match symbol {
// Ints
Symbol::NUM_NAT => Ok(Layout::Builtin(Builtin::Usize)),
Symbol::NUM_INTEGER => Ok(Layout::Builtin(Builtin::Int64)),
Symbol::NUM_I128 => Ok(Layout::Builtin(Builtin::Int128)),
Symbol::NUM_I64 => Ok(Layout::Builtin(Builtin::Int64)),
Symbol::NUM_I32 => Ok(Layout::Builtin(Builtin::Int32)),
Symbol::NUM_I16 => Ok(Layout::Builtin(Builtin::Int16)),
Symbol::NUM_I8 => Ok(Layout::Builtin(Builtin::Int8)),
Symbol::NUM_U128 => Ok(Layout::Builtin(Builtin::Int128)),
Symbol::NUM_U64 => Ok(Layout::Builtin(Builtin::Int64)),
Symbol::NUM_U32 => Ok(Layout::Builtin(Builtin::Int32)),
Symbol::NUM_U16 => Ok(Layout::Builtin(Builtin::Int16)),
Symbol::NUM_U8 => Ok(Layout::Builtin(Builtin::Int8)),
// Floats
Symbol::NUM_FLOATINGPOINT => Ok(Layout::Builtin(Builtin::Float64)),
Symbol::NUM_F64 => Ok(Layout::Builtin(Builtin::Float64)),
Symbol::NUM_F32 => Ok(Layout::Builtin(Builtin::Float32)),
_ => {
panic!(
"Invalid Num.Num type application: {:?}",
Apply(symbol, args)
);
}
},
Alias(_, _, _) => {
todo!("TODO recursively resolve type aliases in num_from_content");
}
Structure(_) => {
panic!("Invalid Num.Num type application: {:?}", content);
}
Error => Err(LayoutProblem::Erroneous),
}
}
fn unwrap_num_tag<'a>(subs: &Subs, var: Variable) -> Result<Layout<'a>, LayoutProblem> {
match subs.get_without_compacting(var).content {
Content::Structure(flat_type) => match flat_type {
FlatType::Apply(Symbol::ATTR_ATTR, args) => {
debug_assert_eq!(args.len(), 2);
let arg_var = args.get(1).unwrap();
unwrap_num_tag(subs, *arg_var)
}
_ => {
todo!("TODO handle Num.@Num flat_type {:?}", flat_type);
}
},
Content::Alias(Symbol::NUM_INTEGER, args, _) => {
debug_assert!(args.len() == 1);
let (_, precision_var) = args[0];
let precision = subs.get_without_compacting(precision_var).content;
match precision {
Content::Alias(symbol, args, _) => {
debug_assert!(args.is_empty());
let builtin = match symbol {
Symbol::NUM_SIGNED128 => Builtin::Int128,
Symbol::NUM_SIGNED64 => Builtin::Int64,
Symbol::NUM_SIGNED32 => Builtin::Int32,
Symbol::NUM_SIGNED16 => Builtin::Int16,
Symbol::NUM_SIGNED8 => Builtin::Int8,
Symbol::NUM_UNSIGNED128 => Builtin::Int128,
Symbol::NUM_UNSIGNED64 => Builtin::Int64,
Symbol::NUM_UNSIGNED32 => Builtin::Int32,
Symbol::NUM_UNSIGNED16 => Builtin::Int16,
Symbol::NUM_UNSIGNED8 => Builtin::Int8,
Symbol::NUM_NATURAL => Builtin::Usize,
_ => unreachable!("not a valid int variant: {:?} {:?}", symbol, args),
};
Ok(Layout::Builtin(builtin))
}
Content::FlexVar(_) | Content::RigidVar(_) => {
// default to i64
Ok(Layout::Builtin(Builtin::Int64))
}
_ => unreachable!("not a valid int variant: {:?}", precision),
}
}
Content::Alias(Symbol::NUM_FLOATINGPOINT, args, _) => {
debug_assert!(args.len() == 1);
let (_, precision_var) = args[0];
let precision = subs.get_without_compacting(precision_var).content;
match precision {
Content::Alias(Symbol::NUM_BINARY32, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Float32))
}
Content::Alias(Symbol::NUM_BINARY64, args, _) => {
debug_assert!(args.is_empty());
Ok(Layout::Builtin(Builtin::Float64))
}
Content::FlexVar(_) | Content::RigidVar(_) => {
// default to f64
Ok(Layout::Builtin(Builtin::Float64))
}
_ => unreachable!("not a valid float variant: {:?}", precision),
}
}
Content::FlexVar(_) | Content::RigidVar(_) => {
// If this was still a (Num *) then default to compiling it to i64
Ok(Layout::Builtin(DEFAULT_NUM_BUILTIN))
}
other => {
todo!("TODO non structure Num.@Num flat_type {:?}", other);
}
}
}
fn dict_layout_from_key_value<'a>(
env: &mut Env<'a, '_>,
key_var: Variable,
value_var: Variable,
) -> Result<Layout<'a>, LayoutProblem> {
match env.subs.get_without_compacting(key_var).content {
Content::Structure(FlatType::Apply(Symbol::ATTR_ATTR, key_args)) => {
debug_assert_eq!(key_args.len(), 2);
let var = *key_args.get(1).unwrap();
dict_layout_from_key_value(env, var, value_var)
}
Content::FlexVar(_) | Content::RigidVar(_) => {
// If this was still a (Dict * *) then it must have been an empty dict
Ok(Layout::Builtin(Builtin::EmptyDict))
}
key_content => {
match env.subs.get_without_compacting(value_var).content {
Content::Structure(FlatType::Apply(Symbol::ATTR_ATTR, value_args)) => {
debug_assert_eq!(value_args.len(), 2);
let var = *value_args.get(1).unwrap();
dict_layout_from_key_value(env, key_var, var)
}
value_content => {
let key_layout = Layout::new_help(env, key_var, key_content)?;
let value_layout = Layout::new_help(env, value_var, value_content)?;
// This is a normal list.
Ok(Layout::Builtin(Builtin::Dict(
env.arena.alloc(key_layout),
env.arena.alloc(value_layout),
)))
}
}
}
}
}
pub fn list_layout_from_elem<'a>(
env: &mut Env<'a, '_>,
elem_var: Variable,
) -> Result<Layout<'a>, LayoutProblem> {
match env.subs.get_without_compacting(elem_var).content {
Content::Structure(FlatType::Apply(Symbol::ATTR_ATTR, args)) => {
debug_assert_eq!(args.len(), 2);
let var = *args.get(1).unwrap();
list_layout_from_elem(env, var)
}
Content::FlexVar(_) | Content::RigidVar(_) => {
// If this was still a (List *) then it must have been an empty list
Ok(Layout::Builtin(Builtin::EmptyList))
}
_ => {
let elem_layout = Layout::from_var(env, elem_var)?;
// This is a normal list.
Ok(Layout::Builtin(Builtin::List(
MemoryMode::Refcounted,
env.arena.alloc(elem_layout),
)))
}
}
}
pub fn mode_from_var(var: Variable, subs: &Subs) -> MemoryMode {
match subs.get_without_compacting(var).content {
Content::Structure(FlatType::Apply(Symbol::ATTR_ATTR, args)) => {
debug_assert_eq!(args.len(), 2);
let uvar = *args.get(0).unwrap();
let content = subs.get_without_compacting(uvar).content;
if content.is_unique(subs) {
MemoryMode::Unique
} else {
MemoryMode::Refcounted
}
}
_ => MemoryMode::Refcounted,
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct LayoutId(u32);
impl LayoutId {
// Returns something like "foo#1" when given a symbol that interns to "foo"
// and a LayoutId of 1.
pub fn to_symbol_string(self, symbol: Symbol, interns: &Interns) -> String {
let ident_string = symbol.ident_string(interns);
let module_string = interns.module_ids.get_name(symbol.module_id()).unwrap();
format!("{}_{}_{}", module_string, ident_string, self.0)
}
}
struct IdsByLayout<'a> {
by_id: MutMap<Layout<'a>, u32>,
next_id: u32,
}
#[derive(Default)]
pub struct LayoutIds<'a> {
by_symbol: MutMap<Symbol, IdsByLayout<'a>>,
}
impl<'a> LayoutIds<'a> {
/// Returns a LayoutId which is unique for the given symbol and layout.
/// If given the same symbol and same layout, returns the same LayoutId.
pub fn get(&mut self, symbol: Symbol, layout: &Layout<'a>) -> LayoutId {
// Note: this function does some weird stuff to satisfy the borrow checker.
// There's probably a nicer way to write it that still works.
let ids = self.by_symbol.entry(symbol).or_insert_with(|| IdsByLayout {
by_id: HashMap::with_capacity_and_hasher(1, default_hasher()),
next_id: 1,
});
// Get the id associated with this layout, or default to next_id.
let answer = ids.by_id.get(layout).copied().unwrap_or(ids.next_id);
// If we had to default to next_id, it must not have been found;
// store the ID we're going to return and increment next_id.
if answer == ids.next_id {
ids.by_id.insert(layout.clone(), ids.next_id);
ids.next_id += 1;
}
LayoutId(answer)
}
}
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