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Make memoize!() a function instead

This commit is contained in:
Jakub Wieczorek 2014-10-14 20:41:50 +02:00
parent c2e8f3b481
commit dbc4a4b53b
4 changed files with 190 additions and 210 deletions
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8
src/librustc/lib.rs
View File

@ -29,12 +29,9 @@ This API is completely unstable and subject to change.
html_root_url = "http://doc.rust-lang.org/nightly/")]
#![allow(deprecated)]
#![allow(unknown_features)]
#![feature(macro_rules, globs, struct_variant, quote)]
#![feature(default_type_params, phase, unsafe_destructor, slicing_syntax)]
#![feature(default_type_params, globs, if_let, import_shadowing, macro_rules, phase, quote)]
#![feature(slicing_syntax, struct_variant, unsafe_destructor)]
#![feature(rustc_diagnostic_macros)]
#![feature(import_shadowing)]
extern crate arena;
extern crate debug;
@ -97,7 +94,6 @@ pub mod middle {
pub mod intrinsicck;
pub mod lang_items;
pub mod liveness;
pub mod macros;
pub mod mem_categorization;
pub mod pat_util;
pub mod privacy;

71
src/librustc/middle/macros.rs
View File

@ -1,71 +0,0 @@
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![macro_escape]
macro_rules! memoize_expand_block(
($cache_map:expr, $cache_key:expr, $($param_name:ident: $param_ty:ty),*) => { {
match ($cache_map).borrow().find(&$cache_key) {
Some(ref result) => return (*result).clone(),
None => {}
}
let result = inner($($param_name), *);
($cache_map).borrow_mut().insert($cache_key, result.clone());
result
} }
)
/// Memoizes a function using a cache that is available by evaluating the
/// `$cache_map` exression in the context of the function's arguments.
/// `$cache_key` is the expression that will be used to compute the cache key
/// for each function invocation.
///
/// The macro assumes the cache to be a RefCell containing a HashMap,
/// which is in practice how most caching in rustc is currently carried out.
///
/// # Example
///
/// ```
/// struct Context {
/// fibonacci_cache: RefCell<HashMap<uint, uint>>
/// }
///
/// memoize!(context.fibonacci_cache, n,
/// fn fibonacci(context: &Context, n: uint) -> uint {
/// match n {
/// 0 | 1 => n,
/// _ => fibonacci(n - 2) + fibonacci(n - 1)
/// }
/// }
/// )
/// ```
macro_rules! memoize(
($cache_map:expr, $cache_key:expr,
fn $name:ident(
$($param_name:ident: $param_ty:ty),*
) -> $output_ty:ty $block:block
) => {
fn $name($($param_name: $param_ty), *) -> $output_ty {
fn inner($($param_name: $param_ty), *) -> $output_ty $block
memoize_expand_block!($cache_map, $cache_key, $($param_name: $param_ty), *)
}
};
($cache_map:expr, $cache_key:expr,
pub fn $name:ident(
$($param_name:ident: $param_ty:ty),*
) -> $output_ty:ty $block:block
) => {
pub fn $name($($param_name: $param_ty), *) -> $output_ty {
fn inner($($param_name: $param_ty), *) -> $output_ty $block
memoize_expand_block!($cache_map, $cache_key, $($param_name: $param_ty), *)
}
}
)

263
src/librustc/middle/ty.rs
View File

@ -33,7 +33,7 @@ use middle;
use util::ppaux::{note_and_explain_region, bound_region_ptr_to_string};
use util::ppaux::{trait_store_to_string, ty_to_string};
use util::ppaux::{Repr, UserString};
use util::common::{indenter};
use util::common::{indenter, memoized, memoized_with_key};
use util::nodemap::{NodeMap, NodeSet, DefIdMap, DefIdSet, FnvHashMap};
use std::cell::{Cell, RefCell};
@ -2117,37 +2117,37 @@ pub fn type_needs_drop(cx: &ctxt, ty: t) -> bool {
// task can free them all at once later. Currently only things
// that only contain scalars and shared boxes can avoid unwind
// cleanups.
memoize!(cx.needs_unwind_cleanup_cache, ty,
fn type_needs_unwind_cleanup_(cx: &ctxt, ty: t, tycache: &mut HashSet<t>) -> bool {
// Prevent infinite recursion
if !tycache.insert(ty) {
return false;
}
let mut needs_unwind_cleanup = false;
maybe_walk_ty(ty, |ty| {
needs_unwind_cleanup |= match get(ty).sty {
ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) |
ty_float(_) | ty_tup(_) | ty_ptr(_) => false,
ty_enum(did, ref substs) =>
enum_variants(cx, did).iter().any(|v|
v.args.iter().any(|aty| {
let t = aty.subst(cx, substs);
type_needs_unwind_cleanup_(cx, t, tycache)
})
),
_ => true
};
!needs_unwind_cleanup
});
needs_unwind_cleanup
}
)
pub fn type_needs_unwind_cleanup(cx: &ctxt, ty: t) -> bool {
type_needs_unwind_cleanup_(cx, ty, &mut HashSet::new())
return memoized(&cx.needs_unwind_cleanup_cache, ty, |ty| {
type_needs_unwind_cleanup_(cx, ty, &mut HashSet::new())
});
fn type_needs_unwind_cleanup_(cx: &ctxt, ty: t, tycache: &mut HashSet<t>) -> bool {
// Prevent infinite recursion
if !tycache.insert(ty) {
return false;
}
let mut needs_unwind_cleanup = false;
maybe_walk_ty(ty, |ty| {
needs_unwind_cleanup |= match get(ty).sty {
ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) |
ty_float(_) | ty_tup(_) | ty_ptr(_) => false,
ty_enum(did, ref substs) =>
enum_variants(cx, did).iter().any(|v|
v.args.iter().any(|aty| {
let t = aty.subst(cx, substs);
type_needs_unwind_cleanup_(cx, t, tycache)
})
),
_ => true
};
!needs_unwind_cleanup
});
needs_unwind_cleanup
}
}
/**
@ -2342,9 +2342,10 @@ pub fn type_interior_is_unsafe(cx: &ctxt, t: ty::t) -> bool {
type_contents(cx, t).interior_unsafe()
}
memoize!(cx.tc_cache, type_id(ty),
pub fn type_contents(cx: &ctxt, ty: t) -> TypeContents {
return tc_ty(cx, ty, &mut HashMap::new());
return memoized_with_key(&cx.tc_cache, ty, |ty| {
tc_ty(cx, ty, &mut HashMap::new())
}, |&ty| type_id(ty));
fn tc_ty(cx: &ctxt,
ty: t,
@ -2659,7 +2660,6 @@ pub fn type_contents(cx: &ctxt, ty: t) -> TypeContents {
}
}
}
)
pub fn type_moves_by_default(cx: &ctxt, ty: t) -> bool {
type_contents(cx, ty).moves_by_default(cx)
@ -4008,23 +4008,23 @@ pub fn impl_or_trait_item(cx: &ctxt, id: ast::DefId) -> ImplOrTraitItem {
/// Returns true if the given ID refers to an associated type and false if it
/// refers to anything else.
memoize!(cx.associated_types, id,
pub fn is_associated_type(cx: &ctxt, id: ast::DefId) -> bool {
if id.krate == ast::LOCAL_CRATE {
match cx.impl_or_trait_items.borrow().find(&id) {
Some(ref item) => {
match **item {
TypeTraitItem(_) => true,
MethodTraitItem(_) => false,
memoized(&cx.associated_types, id, |id: ast::DefId| {
if id.krate == ast::LOCAL_CRATE {
match cx.impl_or_trait_items.borrow().find(&id) {
Some(ref item) => {
match **item {
TypeTraitItem(_) => true,
MethodTraitItem(_) => false,
}
}
None => false,
}
None => false,
} else {
csearch::is_associated_type(&cx.sess.cstore, id)
}
} else {
csearch::is_associated_type(&cx.sess.cstore, id)
}
})
}
)
/// Returns the parameter index that the given associated type corresponds to.
pub fn associated_type_parameter_index(cx: &ctxt,
@ -4080,31 +4080,31 @@ pub fn trait_item_def_ids(cx: &ctxt, id: ast::DefId)
})
}
memoize!(cx.impl_trait_cache, id,
pub fn impl_trait_ref(cx: &ctxt, id: ast::DefId) -> Option<Rc<TraitRef>> {
if id.krate == ast::LOCAL_CRATE {
debug!("(impl_trait_ref) searching for trait impl {:?}", id);
match cx.map.find(id.node) {
Some(ast_map::NodeItem(item)) => {
match item.node {
ast::ItemImpl(_, ref opt_trait, _, _) => {
match opt_trait {
&Some(ref t) => {
Some(ty::node_id_to_trait_ref(cx, t.ref_id))
memoized(&cx.impl_trait_cache, id, |id: ast::DefId| {
if id.krate == ast::LOCAL_CRATE {
debug!("(impl_trait_ref) searching for trait impl {:?}", id);
match cx.map.find(id.node) {
Some(ast_map::NodeItem(item)) => {
match item.node {
ast::ItemImpl(_, ref opt_trait, _, _) => {
match opt_trait {
&Some(ref t) => {
Some(ty::node_id_to_trait_ref(cx, t.ref_id))
}
&None => None
}
&None => None
}
_ => None
}
_ => None
}
_ => None
}
_ => None
} else {
csearch::get_impl_trait(cx, id)
}
} else {
csearch::get_impl_trait(cx, id)
}
})
}
)
pub fn trait_ref_to_def_id(tcx: &ctxt, tr: &ast::TraitRef) -> ast::DefId {
let def = *tcx.def_map.borrow()
@ -4288,66 +4288,67 @@ pub fn type_is_empty(cx: &ctxt, t: t) -> bool {
}
}
memoize!(cx.enum_var_cache, id,
pub fn enum_variants(cx: &ctxt, id: ast::DefId) -> Rc<Vec<Rc<VariantInfo>>> {
if ast::LOCAL_CRATE != id.krate {
Rc::new(csearch::get_enum_variants(cx, id))
} else {
/*
Although both this code and check_enum_variants in typeck/check
call eval_const_expr, it should never get called twice for the same
expr, since check_enum_variants also updates the enum_var_cache
*/
match cx.map.get(id.node) {
ast_map::NodeItem(ref item) => {
match item.node {
ast::ItemEnum(ref enum_definition, _) => {
let mut last_discriminant: Option<Disr> = None;
Rc::new(enum_definition.variants.iter().map(|variant| {
memoized(&cx.enum_var_cache, id, |id: ast::DefId| {
if ast::LOCAL_CRATE != id.krate {
Rc::new(csearch::get_enum_variants(cx, id))
} else {
/*
Although both this code and check_enum_variants in typeck/check
call eval_const_expr, it should never get called twice for the same
expr, since check_enum_variants also updates the enum_var_cache
*/
match cx.map.get(id.node) {
ast_map::NodeItem(ref item) => {
match item.node {
ast::ItemEnum(ref enum_definition, _) => {
let mut last_discriminant: Option<Disr> = None;
Rc::new(enum_definition.variants.iter().map(|variant| {
let mut discriminant = match last_discriminant {
Some(val) => val + 1,
None => INITIAL_DISCRIMINANT_VALUE
};
let mut discriminant = match last_discriminant {
Some(val) => val + 1,
None => INITIAL_DISCRIMINANT_VALUE
};
match variant.node.disr_expr {
Some(ref e) => match const_eval::eval_const_expr_partial(cx, &**e) {
Ok(const_eval::const_int(val)) => {
discriminant = val as Disr
}
Ok(const_eval::const_uint(val)) => {
discriminant = val as Disr
}
Ok(_) => {
cx.sess
.span_err(e.span,
"expected signed integer constant");
}
Err(ref err) => {
cx.sess
.span_err(e.span,
format!("expected constant: {}",
*err).as_slice());
}
},
None => {}
};
match variant.node.disr_expr {
Some(ref e) =>
match const_eval::eval_const_expr_partial(cx, &**e) {
Ok(const_eval::const_int(val)) => {
discriminant = val as Disr
}
Ok(const_eval::const_uint(val)) => {
discriminant = val as Disr
}
Ok(_) => {
cx.sess
.span_err(e.span,
"expected signed integer constant");
}
Err(ref err) => {
cx.sess
.span_err(e.span,
format!("expected constant: {}",
*err).as_slice());
}
},
None => {}
};
last_discriminant = Some(discriminant);
Rc::new(VariantInfo::from_ast_variant(cx, &**variant,
discriminant))
}).collect())
}
_ => {
cx.sess.bug("enum_variants: id not bound to an enum")
last_discriminant = Some(discriminant);
Rc::new(VariantInfo::from_ast_variant(cx, &**variant,
discriminant))
}).collect())
}
_ => {
cx.sess.bug("enum_variants: id not bound to an enum")
}
}
}
_ => cx.sess.bug("enum_variants: id not bound to an enum")
}
_ => cx.sess.bug("enum_variants: id not bound to an enum")
}
}
})
}
)
// Returns information about the enum variant with the given ID:
pub fn enum_variant_with_id(cx: &ctxt,
@ -4372,12 +4373,12 @@ pub fn lookup_item_type(cx: &ctxt,
}
/// Given the did of a trait, returns its canonical trait ref.
memoize!(cx.trait_defs, did,
pub fn lookup_trait_def(cx: &ctxt, did: ast::DefId) -> Rc<ty::TraitDef> {
assert!(did.krate != ast::LOCAL_CRATE);
Rc::new(csearch::get_trait_def(cx, did))
pub fn lookup_trait_def(cx: &ctxt, did: DefId) -> Rc<ty::TraitDef> {
memoized(&cx.trait_defs, did, |did: DefId| {
assert!(did.krate != ast::LOCAL_CRATE);
Rc::new(csearch::get_trait_def(cx, did))
})
}
)
/// Given a reference to a trait, returns the bounds declared on the
/// trait, with appropriate substitutions applied.
@ -4436,21 +4437,21 @@ pub fn lookup_simd(tcx: &ctxt, did: DefId) -> bool {
}
/// Obtain the representation annotation for a struct definition.
memoize!(tcx.repr_hint_cache, did,
pub fn lookup_repr_hints(tcx: &ctxt, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
Rc::new(if did.krate == LOCAL_CRATE {
let mut acc = Vec::new();
ty::each_attr(tcx, did, |meta| {
acc.extend(attr::find_repr_attrs(tcx.sess.diagnostic(),
meta).into_iter());
true
});
acc
} else {
csearch::get_repr_attrs(&tcx.sess.cstore, did)
memoized(&tcx.repr_hint_cache, did, |did: DefId| {
Rc::new(if did.krate == LOCAL_CRATE {
let mut acc = Vec::new();
ty::each_attr(tcx, did, |meta| {
acc.extend(attr::find_repr_attrs(tcx.sess.diagnostic(),
meta).into_iter());
true
});
acc
} else {
csearch::get_repr_attrs(&tcx.sess.cstore, did)
})
})
}
)
// Look up a field ID, whether or not it's local
// Takes a list of type substs in case the struct is generic

58
src/librustc/util/common.rs
View File

@ -1,4 +1,4 @@
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
@ -10,8 +10,9 @@
#![allow(non_camel_case_types)]
use std::hash::{Hash, Hasher};
use std::cell::RefCell;
use std::collections::HashMap;
use std::hash::{Hash, Hasher};
use syntax::ast;
use syntax::visit;
use syntax::visit::Visitor;
@ -155,3 +156,56 @@ pub fn can_reach<S,H:Hasher<S>,T:Eq+Clone+Hash<S>>(
}
return false;
}
/// Memoizes a one-argument closure using the given RefCell containing
/// a type implementing MutableMap to serve as a cache.
///
/// In the future the signature of this function is expected to be:
/// ```
/// pub fn memoized<T: Clone, U: Clone, M: MutableMap<T, U>>(
/// cache: &RefCell<M>,
/// f: &|&: T| -> U
/// ) -> impl |&: T| -> U {
/// ```
/// but currently it is not possible.
///
/// # Example
/// ```
/// struct Context {
/// cache: RefCell<HashMap<uint, uint>>
/// }
///
/// fn factorial(ctxt: &Context, n: uint) -> uint {
/// memoized(&ctxt.cache, n, |n| match n {
/// 0 | 1 => n,
/// _ => factorial(ctxt, n - 2) + factorial(ctxt, n - 1)
/// })
/// }
/// ```
#[inline(always)]
pub fn memoized<T: Clone, U: Clone, M: MutableMap<T, U>>(
cache: &RefCell<M>,
arg: T,
f: |T| -> U
) -> U {
memoized_with_key(cache, arg, f, |arg| arg.clone())
}
#[inline(always)]
pub fn memoized_with_key<T, K, U: Clone, M: MutableMap<K, U>>(
cache: &RefCell<M>,
arg: T,
f: |T| -> U,
k: |&T| -> K
) -> U {
let key = k(&arg);
let result = cache.borrow().find(&key).map(|result| result.clone());
match result {
Some(result) => result,
None => {
let result = f(arg);
cache.borrow_mut().insert(key, result.clone());
result
}
}
}