reset reuse stuff

This commit is contained in:
Folkert 2020-09-04 23:07:45 +02:00
parent f02d907f17
commit b849a3019f
5 changed files with 265 additions and 599 deletions

View file

@ -1,220 +1,188 @@
use crate::expr::Env;
use crate::expr::Expr;
use crate::inc_dec::LocalContext;
use crate::ir::{Expr, Literal, Stmt};
use crate::layout::{Builtin, Layout};
use crate::live_vars;
use bumpalo::collections::Vec;
use bumpalo::Bump;
use roc_collections::all::MutSet;
use roc_module::symbol::Symbol;
pub fn function_r<'a>(env: &mut Env<'a, '_>, body: &'a Expr<'a>) -> Expr<'a> {
use Expr::*;
struct Env<'a, 'b> {
env: crate::ir::Env<'a, 'b>,
ctx: LocalContext<'a>,
}
match body {
Switch {
cond_symbol,
branches,
cond,
cond_layout,
default_branch,
ret_layout,
} => {
let stack_size = cond_layout.stack_size(env.pointer_size);
let mut new_branches = Vec::with_capacity_in(branches.len(), env.arena);
fn may_reuse<'a>(x: Layout<'a>, y: Layout<'a>) -> bool {
// a heuristic; we really only want the same "type" to be reused.
// we could also compare actual stack size.
x == y
}
for (tag, stores, branch) in branches.iter() {
let new_branch = function_d(env, *cond_symbol, stack_size as _, branch);
fn try_function_s<'a>(
env: &mut Env<'a, '_>,
x: Symbol,
layout: Layout<'a>,
stmt: &'a Stmt<'a>,
) -> &'a Stmt<'a> {
let arena = env.env.arena;
new_branches.push((*tag, *stores, new_branch));
}
let w = env.env.unique_symbol();
let new_default_branch = (
default_branch.0,
&*env.arena.alloc(function_d(
env,
*cond_symbol,
stack_size as _,
default_branch.1,
)),
);
match function_s(env, w, stmt) {
None => stmt,
Some(new) => arena.alloc(Stmt::Let(w, Expr::Reset(x), layout, new)),
}
}
fn function_s<'a>(env: &mut Env<'a, '_>, w: Symbol, stmt: &'a Stmt<'a>) -> Option<&'a Stmt<'a>> {
use Stmt::*;
let arena = env.env.arena;
match stmt {
_ => todo!(),
}
}
fn function_d_main<'a>(
env: &mut Env<'a, '_>,
x: Symbol,
layout: Layout<'a>,
stmt: &'a Stmt<'a>,
) -> (Option<&'a Stmt<'a>>, bool) {
/*
let c = layout;
use Stmt::*;
let arena = env.env.arena;
match stmt {
Switch {
cond_symbol: *cond_symbol,
branches: new_branches.into_bump_slice(),
default_branch: new_default_branch,
ret_layout: ret_layout.clone(),
cond: *cond,
cond_layout: cond_layout.clone(),
cond_symbol,
cond_layout,
branches,
default_branch,
ret_layout,
} => {
// TODO only conditionally re-build the expression
let live = live_vars::collect_stmt(stmt, env.ctx)
let branches = Vec::from_iter_in(
branches.iter().map(|(label, branch)| {
let branch = function_r(env, branch).unwrap_or(branch);
let branch = function_d(env, *cond_symbol, cond_layout.clone(), branch)
.unwrap_or(branch);
(*label, branch.clone())
}),
arena,
)
.into_bump_slice();
let default_branch = function_r(env, default_branch).unwrap_or(default_branch);
let default_branch = function_d(env, *cond_symbol, cond_layout.clone(), default_branch)
.unwrap_or(default_branch);
let switch = Switch {
cond_symbol: *cond_symbol,
branches,
default_branch,
cond_layout: cond_layout.clone(),
ret_layout: ret_layout.clone(),
};
Some(arena.alloc(switch))
}
}
Cond {
cond_symbol,
cond_layout,
branching_symbol,
branching_layout,
pass,
fail,
ret_layout,
} => {
let stack_size = cond_layout.stack_size(env.pointer_size);
let new_pass = (
pass.0,
&*env
.arena
.alloc(function_d(env, *cond_symbol, stack_size as _, pass.1)),
);
Join { .. } => todo!(),
let new_fail = (
fail.0,
&*env
.arena
.alloc(function_d(env, *cond_symbol, stack_size as _, fail.1)),
);
Ret(_) | Jump(_, _) | RuntimeError(_) => None,
Inc(x, b) => match function_r(env, b) {
None => None,
Some(new_b) => Some(arena.alloc(Inc(*x, new_b))),
},
Dec(x, b) => match function_r(env, b) {
None => None,
Some(new_b) => Some(arena.alloc(Dec(*x, new_b))),
},
Let(x, v, l, b) => match function_r(env, b) {
None => None,
Some(new_b) => Some(arena.alloc(Let(*x, v.clone(), l.clone(), new_b))),
},
Cond {
cond_symbol: *cond_symbol,
cond_layout: cond_layout.clone(),
branching_symbol: *branching_symbol,
branching_layout: branching_layout.clone(),
ret_layout: ret_layout.clone(),
pass: new_pass,
fail: new_fail,
cond_symbol,
cond_layout,
branching_symbol,
branching_layout,
pass,
fail,
ret_layout,
} => {
// TODO only conditionally re-build the expression
let pass = function_r(env, pass).unwrap_or(pass);
let pass = function_d(env, *cond_symbol, cond_layout.clone(), pass).unwrap_or(pass);
let fail = function_r(env, fail).unwrap_or(fail);
let fail = function_d(env, *cond_symbol, cond_layout.clone(), fail).unwrap_or(fail);
let stmt = Cond {
cond_symbol: *cond_symbol,
cond_layout: cond_layout.clone(),
branching_symbol: *branching_symbol,
branching_layout: branching_layout.clone(),
pass,
fail,
ret_layout: ret_layout.clone(),
};
Some(arena.alloc(stmt))
}
}
Store(stores, body) => {
let new_body = function_r(env, body);
Store(stores, env.arena.alloc(new_body))
}
DecAfter(symbol, body) => {
let new_body = function_r(env, body);
DecAfter(*symbol, env.arena.alloc(new_body))
}
CallByName { .. }
| CallByPointer(_, _, _)
| RunLowLevel(_, _)
| Tag { .. }
| Struct(_)
| Array { .. }
| AccessAtIndex { .. } => {
// TODO
// how often are `when` expressions in one of the above?
body.clone()
}
Int(_)
| Float(_)
| Str(_)
| Bool(_)
| Byte(_)
| Load(_)
| EmptyArray
| Inc(_, _)
| FunctionPointer(_, _)
| RuntimeError(_)
| RuntimeErrorFunction(_) => body.clone(),
Reset(_, _) | Reuse(_, _) => unreachable!("reset/reuse should not have been inserted yet!"),
}
*/
panic!();
}
fn function_d<'a>(
env: &mut Env<'a, '_>,
z: Symbol,
stack_size: usize,
body: &'a Expr<'a>,
) -> Expr<'a> {
let symbols = symbols_in_expr(body);
if symbols.contains(&z) {
return body.clone();
}
if let Ok(reused) = function_s(env, z, stack_size, body) {
Expr::Reset(z, env.arena.alloc(reused))
} else {
body.clone()
}
/*
match body {
Expr::Tag { .. } => Some(env.arena.alloc(Expr::Reuse(w, body))),
_ => None,
}
*/
x: Symbol,
layout: Layout<'a>,
stmt: &'a Stmt<'a>,
) -> Option<&'a Stmt<'a>> {
let c = layout;
todo!();
}
fn function_s<'a>(
env: &mut Env<'a, '_>,
w: Symbol,
stack_size: usize,
body: &'a Expr<'a>,
) -> Result<&'a Expr<'a>, &'a Expr<'a>> {
use Expr::*;
fn function_r<'a>(env: &mut Env<'a, '_>, stmt: &'a Stmt<'a>) -> Option<&'a Stmt<'a>> {
use Stmt::*;
match body {
Tag { tag_layout, .. } => {
if tag_layout.stack_size(env.pointer_size) as usize <= stack_size {
Ok(env.arena.alloc(Expr::Reuse(w, body)))
} else {
Err(body)
}
}
let arena = env.env.arena;
Array { .. } | Struct(_) => {
// TODO
Err(body)
}
match stmt {
Join { .. } => todo!(),
Switch {
cond_symbol,
branches,
cond,
cond_layout,
default_branch,
ret_layout,
} => {
// we can re-use `w` in each branch
let mut has_been_reused = false;
let mut new_branches = Vec::with_capacity_in(branches.len(), env.arena);
for (tag, stores, branch) in branches.iter() {
match function_s(env, *cond_symbol, stack_size as _, branch) {
Ok(new_branch) => {
has_been_reused = true;
new_branches.push((*tag, *stores, new_branch.clone()));
}
Err(new_branch) => {
new_branches.push((*tag, *stores, new_branch.clone()));
}
}
}
Ret(_) | Jump(_, _) | RuntimeError(_) => None,
let new_default_branch = (
default_branch.0,
match function_s(env, *cond_symbol, stack_size, default_branch.1) {
Ok(new) => {
has_been_reused = true;
new
}
Err(new) => new,
},
);
let result = env.arena.alloc(Switch {
cond_symbol: *cond_symbol,
branches: new_branches.into_bump_slice(),
default_branch: new_default_branch,
ret_layout: ret_layout.clone(),
cond: *cond,
cond_layout: cond_layout.clone(),
});
Inc(x, b) => match function_r(env, b) {
None => None,
Some(new_b) => Some(arena.alloc(Inc(*x, new_b))),
},
if has_been_reused {
Ok(result)
} else {
Err(result)
}
}
Dec(x, b) => match function_r(env, b) {
None => None,
Some(new_b) => Some(arena.alloc(Dec(*x, new_b))),
},
Let(x, v, l, b) => match function_r(env, b) {
None => None,
Some(new_b) => Some(arena.alloc(Let(*x, v.clone(), l.clone(), new_b))),
},
Cond {
cond_symbol,
@ -225,424 +193,60 @@ fn function_s<'a>(
fail,
ret_layout,
} => {
let mut has_been_reused = false;
let new_pass = (
pass.0,
match function_s(env, *cond_symbol, stack_size, pass.1) {
Ok(new) => {
has_been_reused = true;
new
}
Err(new) => new,
},
);
// TODO only conditionally re-build the expression
let new_fail = (
fail.0,
match function_s(env, *cond_symbol, stack_size, fail.1) {
Ok(new) => {
has_been_reused = true;
new
}
Err(new) => new,
},
);
let pass = function_r(env, pass).unwrap_or(pass);
let pass = function_d(env, *cond_symbol, cond_layout.clone(), pass).unwrap_or(pass);
let result = env.arena.alloc(Cond {
let fail = function_r(env, fail).unwrap_or(fail);
let fail = function_d(env, *cond_symbol, cond_layout.clone(), fail).unwrap_or(fail);
let stmt = Cond {
cond_symbol: *cond_symbol,
cond_layout: cond_layout.clone(),
branching_symbol: *branching_symbol,
branching_layout: branching_layout.clone(),
pass,
fail,
ret_layout: ret_layout.clone(),
pass: new_pass,
fail: new_fail,
});
};
if has_been_reused {
Ok(result)
} else {
Err(result)
}
Some(arena.alloc(stmt))
}
Switch {
cond_symbol,
cond_layout,
branches,
default_branch,
ret_layout,
} => {
// TODO only conditionally re-build the expression
Store(stores, expr) => {
let new_expr = function_s(env, w, stack_size, expr)?;
let branches = Vec::from_iter_in(
branches.iter().map(|(label, branch)| {
let branch = function_r(env, branch).unwrap_or(branch);
let branch = function_d(env, *cond_symbol, cond_layout.clone(), branch)
.unwrap_or(branch);
Ok(env.arena.alloc(Store(*stores, new_expr)))
}
(*label, branch.clone())
}),
arena,
)
.into_bump_slice();
DecAfter(symbol, expr) => {
let new_expr = function_s(env, w, stack_size, expr)?;
let default_branch = function_r(env, default_branch).unwrap_or(default_branch);
let default_branch = function_d(env, *cond_symbol, cond_layout.clone(), default_branch)
.unwrap_or(default_branch);
Ok(env.arena.alloc(DecAfter(*symbol, new_expr)))
}
CallByName { .. } | CallByPointer(_, _, _) | RunLowLevel(_, _) | AccessAtIndex { .. } => {
// TODO
// how often are `Tag` expressions in one of the above?
Err(body)
}
Int(_)
| Float(_)
| Str(_)
| Bool(_)
| Byte(_)
| Load(_)
| EmptyArray
| Inc(_, _)
| FunctionPointer(_, _)
| RuntimeError(_)
| RuntimeErrorFunction(_) => Err(body),
Reset(_, _) | Reuse(_, _) => {
unreachable!("reset/reuse should not have been introduced yet")
}
}
}
fn free_variables<'a>(initial: &Expr<'a>) -> MutSet<Symbol> {
use Expr::*;
let mut seen = MutSet::default();
let mut bound = MutSet::default();
let mut stack = vec![initial];
// in other words, variables that are referenced, but not stored
while let Some(expr) = stack.pop() {
match expr {
FunctionPointer(symbol, _) | Load(symbol) => {
seen.insert(*symbol);
}
Reset(symbol, expr) | Reuse(symbol, expr) => {
seen.insert(*symbol);
stack.push(expr)
}
Cond {
cond_symbol,
branching_symbol,
pass,
fail,
..
} => {
seen.insert(*cond_symbol);
seen.insert(*branching_symbol);
for (symbol, _, expr) in pass.0.iter() {
seen.insert(*symbol);
stack.push(expr)
}
for (symbol, _, expr) in fail.0.iter() {
seen.insert(*symbol);
stack.push(expr)
}
}
Switch {
cond,
cond_symbol,
let switch = Switch {
cond_symbol: *cond_symbol,
branches,
default_branch,
..
} => {
stack.push(cond);
seen.insert(*cond_symbol);
cond_layout: cond_layout.clone(),
ret_layout: ret_layout.clone(),
};
for (_, stores, expr) in branches.iter() {
stack.push(expr);
for (symbol, _, expr) in stores.iter() {
bound.insert(*symbol);
stack.push(expr)
}
}
stack.push(default_branch.1);
for (symbol, _, expr) in default_branch.0.iter() {
seen.insert(*symbol);
stack.push(expr)
}
}
Store(stores, body) => {
for (symbol, _, expr) in stores.iter() {
bound.insert(*symbol);
stack.push(&expr)
}
stack.push(body)
}
DecAfter(symbol, body) | Inc(symbol, body) => {
seen.insert(*symbol);
stack.push(body);
}
CallByName { name, args, .. } => {
seen.insert(*name);
for (expr, _) in args.iter() {
stack.push(expr);
}
}
CallByPointer(function, args, _) => {
stack.push(function);
stack.extend(args.iter());
}
RunLowLevel(_, args) => {
for (expr, _) in args.iter() {
stack.push(expr);
}
}
Tag { arguments, .. } => {
for (symbol, _) in arguments.iter() {
seen.insert(*symbol);
}
}
Struct(arguments) => {
for (expr, _) in arguments.iter() {
stack.push(expr);
}
}
Array { elems, .. } => {
for expr in elems.iter() {
stack.push(expr);
}
}
AccessAtIndex { expr, .. } => {
stack.push(expr);
}
Int(_)
| Float(_)
| Str(_)
| Bool(_)
| Byte(_)
| EmptyArray
| RuntimeError(_)
| RuntimeErrorFunction(_) => {}
Some(arena.alloc(switch))
}
}
for symbol in bound.iter() {
seen.remove(symbol);
}
seen
}
fn symbols_in_expr<'a>(initial: &Expr<'a>) -> MutSet<Symbol> {
use Expr::*;
let mut result = MutSet::default();
let mut stack = vec![initial];
while let Some(expr) = stack.pop() {
match expr {
FunctionPointer(symbol, _) | Load(symbol) => {
result.insert(*symbol);
}
Reset(symbol, expr) | Reuse(symbol, expr) => {
result.insert(*symbol);
stack.push(expr)
}
Cond {
cond_symbol,
branching_symbol,
pass,
fail,
..
} => {
result.insert(*cond_symbol);
result.insert(*branching_symbol);
for (symbol, _, expr) in pass.0.iter() {
result.insert(*symbol);
stack.push(expr)
}
for (symbol, _, expr) in fail.0.iter() {
result.insert(*symbol);
stack.push(expr)
}
}
Switch {
cond,
cond_symbol,
branches,
default_branch,
..
} => {
stack.push(cond);
result.insert(*cond_symbol);
for (_, stores, expr) in branches.iter() {
stack.push(expr);
for (symbol, _, expr) in stores.iter() {
result.insert(*symbol);
stack.push(expr)
}
}
stack.push(default_branch.1);
for (symbol, _, expr) in default_branch.0.iter() {
result.insert(*symbol);
stack.push(expr)
}
}
Store(stores, body) => {
for (symbol, _, expr) in stores.iter() {
result.insert(*symbol);
stack.push(&expr)
}
stack.push(body)
}
DecAfter(symbol, body) | Inc(symbol, body) => {
result.insert(*symbol);
stack.push(body);
}
CallByName { name, args, .. } => {
result.insert(*name);
for (expr, _) in args.iter() {
stack.push(expr);
}
}
CallByPointer(function, args, _) => {
stack.push(function);
stack.extend(args.iter());
}
RunLowLevel(_, args) => {
for (expr, _) in args.iter() {
stack.push(expr);
}
}
Tag { arguments, .. } => {
for (symbol, _) in arguments.iter() {
result.insert(*symbol);
}
}
Struct(arguments) => {
for (expr, _) in arguments.iter() {
stack.push(expr);
}
}
Array { elems, .. } => {
for expr in elems.iter() {
stack.push(expr);
}
}
AccessAtIndex { expr, .. } => {
stack.push(expr);
}
Int(_)
| Float(_)
| Str(_)
| Bool(_)
| Byte(_)
| EmptyArray
| RuntimeError(_)
| RuntimeErrorFunction(_) => {}
}
}
result
}
pub fn function_c<'a>(env: &mut Env<'a, '_>, body: Expr<'a>) -> Expr<'a> {
let fv = free_variables(&body);
function_c_help(env, body, fv)
}
pub fn function_c_help<'a>(env: &mut Env<'a, '_>, body: Expr<'a>, fv: MutSet<Symbol>) -> Expr<'a> {
use Expr::*;
match body {
Tag { arguments, .. } => {
let symbols = arguments
.iter()
.map(|(x, _)| x)
.copied()
.collect::<std::vec::Vec<_>>();
function_c_app(env, &symbols, &fv, body)
}
_ => body,
}
}
fn function_c_app<'a>(
env: &mut Env<'a, '_>,
arguments: &[Symbol],
orig_fv: &MutSet<Symbol>,
mut application: Expr<'a>,
) -> Expr<'a> {
// in the future, this will need to be a check
let is_owned = true;
for (i, y) in arguments.iter().rev().enumerate() {
if is_owned {
let mut fv = orig_fv.clone();
fv.extend(arguments[i..].iter().copied());
application = insert_increment(env, *y, fv, application)
} else {
unimplemented!("owned references are not implemented yet")
}
}
application
}
fn insert_increment<'a>(
env: &mut Env<'a, '_>,
symbol: Symbol,
live_variables: MutSet<Symbol>,
body: Expr<'a>,
) -> Expr<'a> {
// in the future, this will need to be a check
let is_owned = true;
if is_owned && !live_variables.contains(&symbol) {
body
} else {
Expr::Inc(symbol, env.arena.alloc(body))
}
}
fn insert_decrement<'a>(env: &mut Env<'a, '_>, symbols: &[Symbol], mut body: Expr<'a>) -> Expr<'a> {
// in the future, this will need to be a check
let is_owned = true;
let fv = free_variables(&body);
for symbol in symbols.iter() {
let is_dead = !fv.contains(&symbol);
if is_owned && is_dead {
body = Expr::DecAfter(*symbol, env.arena.alloc(body));
}
}
body
}