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liveness: Use newtype_index for Variable and LiveNode

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This commit is contained in:
Tomasz Miąsko 2020-09-26 00:00:00 +00:00
parent 49d1ce00f3
commit 57d38975cc
4 changed files with 47 additions and 66 deletions
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1
Cargo.lock
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@ -3891,6 +3891,7 @@ dependencies = [
"rustc_hir", "rustc_hir",
"rustc_index", "rustc_index",
"rustc_middle", "rustc_middle",
"rustc_serialize",
"rustc_session", "rustc_session",
"rustc_span", "rustc_span",
"rustc_target", "rustc_target",

1
compiler/rustc_passes/Cargo.toml
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@ -15,5 +15,6 @@ rustc_index = { path = "../rustc_index" }
rustc_session = { path = "../rustc_session" } rustc_session = { path = "../rustc_session" }
rustc_target = { path = "../rustc_target" } rustc_target = { path = "../rustc_target" }
rustc_ast = { path = "../rustc_ast" } rustc_ast = { path = "../rustc_ast" }
rustc_serialize = { path = "../rustc_serialize" }
rustc_span = { path = "../rustc_span" } rustc_span = { path = "../rustc_span" }
rustc_trait_selection = { path = "../rustc_trait_selection" } rustc_trait_selection = { path = "../rustc_trait_selection" }

2
compiler/rustc_passes/src/lib.rs
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@ -5,6 +5,8 @@
//! This API is completely unstable and subject to change. //! This API is completely unstable and subject to change.
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")] #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(const_fn)]
#![feature(const_panic)]
#![feature(in_band_lifetimes)] #![feature(in_band_lifetimes)]
#![feature(nll)] #![feature(nll)]
#![feature(or_patterns)] #![feature(or_patterns)]

109
compiler/rustc_passes/src/liveness.rs
View File

@ -62,13 +62,13 @@
//! - `reader`: the `LiveNode` ID of some node which will read the value //! - `reader`: the `LiveNode` ID of some node which will read the value
//! that `V` holds on entry to `N`. Formally: a node `M` such //! that `V` holds on entry to `N`. Formally: a node `M` such
//! that there exists a path `P` from `N` to `M` where `P` does not //! that there exists a path `P` from `N` to `M` where `P` does not
//! write `V`. If the `reader` is `invalid_node()`, then the current //! write `V`. If the `reader` is `INVALID_NODE`, then the current
//! value will never be read (the variable is dead, essentially). //! value will never be read (the variable is dead, essentially).
//! //!
//! - `writer`: the `LiveNode` ID of some node which will write the //! - `writer`: the `LiveNode` ID of some node which will write the
//! variable `V` and which is reachable from `N`. Formally: a node `M` //! variable `V` and which is reachable from `N`. Formally: a node `M`
//! such that there exists a path `P` from `N` to `M` and `M` writes //! such that there exists a path `P` from `N` to `M` and `M` writes
//! `V`. If the `writer` is `invalid_node()`, then there is no writer //! `V`. If the `writer` is `INVALID_NODE`, then there is no writer
//! of `V` that follows `N`. //! of `V` that follows `N`.
//! //!
//! - `used`: a boolean value indicating whether `V` is *used*. We //! - `used`: a boolean value indicating whether `V` is *used*. We
@ -92,6 +92,7 @@ use rustc_hir::def::*;
use rustc_hir::def_id::LocalDefId; use rustc_hir::def_id::LocalDefId;
use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor}; use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor};
use rustc_hir::{Expr, HirId, HirIdMap, HirIdSet, Node}; use rustc_hir::{Expr, HirId, HirIdMap, HirIdSet, Node};
use rustc_index::vec::IndexVec;
use rustc_middle::hir::map::Map; use rustc_middle::hir::map::Map;
use rustc_middle::ty::query::Providers; use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{self, TyCtxt}; use rustc_middle::ty::{self, TyCtxt};
@ -100,26 +101,20 @@ use rustc_span::symbol::{kw, sym, Symbol};
use rustc_span::Span; use rustc_span::Span;
use std::collections::VecDeque; use std::collections::VecDeque;
use std::fmt;
use std::io; use std::io;
use std::io::prelude::*; use std::io::prelude::*;
use std::rc::Rc; use std::rc::Rc;
#[derive(Copy, Clone, PartialEq)] rustc_index::newtype_index! {
struct Variable(u32); pub struct Variable {
DEBUG_FORMAT = "v({})",
#[derive(Copy, Clone, PartialEq)]
struct LiveNode(u32);
impl Variable {
fn get(&self) -> usize {
self.0 as usize
} }
} }
impl LiveNode { rustc_index::newtype_index! {
fn get(&self) -> usize { pub struct LiveNode {
self.0 as usize DEBUG_FORMAT = "ln({})",
const INVALID_NODE = LiveNode::MAX_AS_U32,
} }
} }
@ -183,18 +178,6 @@ pub fn provide(providers: &mut Providers) {
*providers = Providers { check_mod_liveness, ..*providers }; *providers = Providers { check_mod_liveness, ..*providers };
} }
impl fmt::Debug for LiveNode {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "ln({})", self.get())
}
}
impl fmt::Debug for Variable {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "v({})", self.get())
}
}
// ______________________________________________________________________ // ______________________________________________________________________
// Creating ir_maps // Creating ir_maps
// //
@ -218,15 +201,11 @@ impl fmt::Debug for Variable {
// assignment. And so forth. // assignment. And so forth.
impl LiveNode { impl LiveNode {
fn is_valid(&self) -> bool { fn is_valid(self) -> bool {
self.0 != u32::MAX self != INVALID_NODE
} }
} }
fn invalid_node() -> LiveNode {
LiveNode(u32::MAX)
}
struct CaptureInfo { struct CaptureInfo {
ln: LiveNode, ln: LiveNode,
var_hid: HirId, var_hid: HirId,
@ -252,8 +231,8 @@ struct IrMaps<'tcx> {
live_node_map: HirIdMap<LiveNode>, live_node_map: HirIdMap<LiveNode>,
variable_map: HirIdMap<Variable>, variable_map: HirIdMap<Variable>,
capture_info_map: HirIdMap<Rc<Vec<CaptureInfo>>>, capture_info_map: HirIdMap<Rc<Vec<CaptureInfo>>>,
var_kinds: Vec<VarKind>, var_kinds: IndexVec<Variable, VarKind>,
lnks: Vec<LiveNodeKind>, lnks: IndexVec<LiveNode, LiveNodeKind>,
} }
impl IrMaps<'tcx> { impl IrMaps<'tcx> {
@ -264,14 +243,13 @@ impl IrMaps<'tcx> {
live_node_map: HirIdMap::default(), live_node_map: HirIdMap::default(),
variable_map: HirIdMap::default(), variable_map: HirIdMap::default(),
capture_info_map: Default::default(), capture_info_map: Default::default(),
var_kinds: Vec::new(), var_kinds: IndexVec::new(),
lnks: Vec::new(), lnks: IndexVec::new(),
} }
} }
fn add_live_node(&mut self, lnk: LiveNodeKind) -> LiveNode { fn add_live_node(&mut self, lnk: LiveNodeKind) -> LiveNode {
let ln = LiveNode(self.lnks.len() as u32); let ln = self.lnks.push(lnk);
self.lnks.push(lnk);
debug!("{:?} is of kind {}", ln, live_node_kind_to_string(lnk, self.tcx)); debug!("{:?} is of kind {}", ln, live_node_kind_to_string(lnk, self.tcx));
@ -286,8 +264,7 @@ impl IrMaps<'tcx> {
} }
fn add_variable(&mut self, vk: VarKind) -> Variable { fn add_variable(&mut self, vk: VarKind) -> Variable {
let v = Variable(self.var_kinds.len() as u32); let v = self.var_kinds.push(vk);
self.var_kinds.push(vk);
match vk { match vk {
Local(LocalInfo { id: node_id, .. }) | Param(node_id, _) | Upvar(node_id, _) => { Local(LocalInfo { id: node_id, .. }) | Param(node_id, _) | Upvar(node_id, _) => {
@ -310,13 +287,13 @@ impl IrMaps<'tcx> {
} }
fn variable_name(&self, var: Variable) -> Symbol { fn variable_name(&self, var: Variable) -> Symbol {
match self.var_kinds[var.get()] { match self.var_kinds[var] {
Local(LocalInfo { name, .. }) | Param(_, name) | Upvar(_, name) => name, Local(LocalInfo { name, .. }) | Param(_, name) | Upvar(_, name) => name,
} }
} }
fn variable_is_shorthand(&self, var: Variable) -> bool { fn variable_is_shorthand(&self, var: Variable) -> bool {
match self.var_kinds[var.get()] { match self.var_kinds[var] {
Local(LocalInfo { is_shorthand, .. }) => is_shorthand, Local(LocalInfo { is_shorthand, .. }) => is_shorthand,
Param(..) | Upvar(..) => false, Param(..) | Upvar(..) => false,
} }
@ -327,7 +304,7 @@ impl IrMaps<'tcx> {
} }
fn lnk(&self, ln: LiveNode) -> LiveNodeKind { fn lnk(&self, ln: LiveNode) -> LiveNodeKind {
self.lnks[ln.get()] self.lnks[ln]
} }
} }
@ -556,10 +533,10 @@ struct RWUTable {
unpacked_rwus: Vec<RWU>, unpacked_rwus: Vec<RWU>,
} }
// A constant representing `RWU { reader: invalid_node(); writer: invalid_node(); used: false }`. // A constant representing `RWU { reader: INVALID_NODE; writer: INVALID_NODE; used: false }`.
const INV_INV_FALSE: u32 = u32::MAX; const INV_INV_FALSE: u32 = u32::MAX;
// A constant representing `RWU { reader: invalid_node(); writer: invalid_node(); used: true }`. // A constant representing `RWU { reader: INVALID_NODE; writer: INVALID_NODE; used: true }`.
const INV_INV_TRUE: u32 = u32::MAX - 1; const INV_INV_TRUE: u32 = u32::MAX - 1;
impl RWUTable { impl RWUTable {
@ -570,8 +547,8 @@ impl RWUTable {
fn get(&self, idx: usize) -> RWU { fn get(&self, idx: usize) -> RWU {
let packed_rwu = self.packed_rwus[idx]; let packed_rwu = self.packed_rwus[idx];
match packed_rwu { match packed_rwu {
INV_INV_FALSE => RWU { reader: invalid_node(), writer: invalid_node(), used: false }, INV_INV_FALSE => RWU { reader: INVALID_NODE, writer: INVALID_NODE, used: false },
INV_INV_TRUE => RWU { reader: invalid_node(), writer: invalid_node(), used: true }, INV_INV_TRUE => RWU { reader: INVALID_NODE, writer: INVALID_NODE, used: true },
_ => self.unpacked_rwus[packed_rwu as usize], _ => self.unpacked_rwus[packed_rwu as usize],
} }
} }
@ -579,7 +556,7 @@ impl RWUTable {
fn get_reader(&self, idx: usize) -> LiveNode { fn get_reader(&self, idx: usize) -> LiveNode {
let packed_rwu = self.packed_rwus[idx]; let packed_rwu = self.packed_rwus[idx];
match packed_rwu { match packed_rwu {
INV_INV_FALSE | INV_INV_TRUE => invalid_node(), INV_INV_FALSE | INV_INV_TRUE => INVALID_NODE,
_ => self.unpacked_rwus[packed_rwu as usize].reader, _ => self.unpacked_rwus[packed_rwu as usize].reader,
} }
} }
@ -587,7 +564,7 @@ impl RWUTable {
fn get_writer(&self, idx: usize) -> LiveNode { fn get_writer(&self, idx: usize) -> LiveNode {
let packed_rwu = self.packed_rwus[idx]; let packed_rwu = self.packed_rwus[idx];
match packed_rwu { match packed_rwu {
INV_INV_FALSE | INV_INV_TRUE => invalid_node(), INV_INV_FALSE | INV_INV_TRUE => INVALID_NODE,
_ => self.unpacked_rwus[packed_rwu as usize].writer, _ => self.unpacked_rwus[packed_rwu as usize].writer,
} }
} }
@ -607,7 +584,7 @@ impl RWUTable {
} }
fn assign_unpacked(&mut self, idx: usize, rwu: RWU) { fn assign_unpacked(&mut self, idx: usize, rwu: RWU) {
if rwu.reader == invalid_node() && rwu.writer == invalid_node() { if rwu.reader == INVALID_NODE && rwu.writer == INVALID_NODE {
// When we overwrite an indexing entry in `self.packed_rwus` with // When we overwrite an indexing entry in `self.packed_rwus` with
// `INV_INV_{TRUE,FALSE}` we don't remove the corresponding entry // `INV_INV_{TRUE,FALSE}` we don't remove the corresponding entry
// from `self.unpacked_rwus`; it's not worth the effort, and we // from `self.unpacked_rwus`; it's not worth the effort, and we
@ -634,7 +611,7 @@ struct Liveness<'a, 'tcx> {
ir: &'a mut IrMaps<'tcx>, ir: &'a mut IrMaps<'tcx>,
typeck_results: &'a ty::TypeckResults<'tcx>, typeck_results: &'a ty::TypeckResults<'tcx>,
param_env: ty::ParamEnv<'tcx>, param_env: ty::ParamEnv<'tcx>,
successors: Vec<LiveNode>, successors: IndexVec<LiveNode, LiveNode>,
rwu_table: RWUTable, rwu_table: RWUTable,
/// A live node representing a point of execution before closure entry & /// A live node representing a point of execution before closure entry &
@ -667,7 +644,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
ir, ir,
typeck_results, typeck_results,
param_env, param_env,
successors: vec![invalid_node(); num_live_nodes], successors: IndexVec::from_elem_n(INVALID_NODE, num_live_nodes),
rwu_table: RWUTable::new(num_live_nodes * num_vars), rwu_table: RWUTable::new(num_live_nodes * num_vars),
closure_ln, closure_ln,
exit_ln, exit_ln,
@ -708,7 +685,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
} }
fn idx(&self, ln: LiveNode, var: Variable) -> usize { fn idx(&self, ln: LiveNode, var: Variable) -> usize {
ln.get() * self.ir.var_kinds.len() + var.get() ln.index() * self.ir.var_kinds.len() + var.index()
} }
fn live_on_entry(&self, ln: LiveNode, var: Variable) -> Option<LiveNodeKind> { fn live_on_entry(&self, ln: LiveNode, var: Variable) -> Option<LiveNodeKind> {
@ -719,7 +696,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
// Is this variable live on entry to any of its successor nodes? // Is this variable live on entry to any of its successor nodes?
fn live_on_exit(&self, ln: LiveNode, var: Variable) -> Option<LiveNodeKind> { fn live_on_exit(&self, ln: LiveNode, var: Variable) -> Option<LiveNodeKind> {
let successor = self.successors[ln.get()]; let successor = self.successors[ln];
self.live_on_entry(successor, var) self.live_on_entry(successor, var)
} }
@ -735,7 +712,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
} }
fn assigned_on_exit(&self, ln: LiveNode, var: Variable) -> Option<LiveNodeKind> { fn assigned_on_exit(&self, ln: LiveNode, var: Variable) -> Option<LiveNodeKind> {
let successor = self.successors[ln.get()]; let successor = self.successors[ln];
self.assigned_on_entry(successor, var) self.assigned_on_entry(successor, var)
} }
@ -743,8 +720,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
where where
F: FnMut(&mut Liveness<'a, 'tcx>, usize, usize), F: FnMut(&mut Liveness<'a, 'tcx>, usize, usize),
{ {
let node_base_idx = self.idx(ln, Variable(0)); let node_base_idx = self.idx(ln, Variable::from(0u32));
let succ_base_idx = self.idx(succ_ln, Variable(0)); let succ_base_idx = self.idx(succ_ln, Variable::from(0u32));
for var_idx in 0..self.ir.var_kinds.len() { for var_idx in 0..self.ir.var_kinds.len() {
op(self, node_base_idx + var_idx, succ_base_idx + var_idx); op(self, node_base_idx + var_idx, succ_base_idx + var_idx);
} }
@ -754,11 +731,11 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
where where
F: FnMut(usize) -> bool, F: FnMut(usize) -> bool,
{ {
let node_base_idx = self.idx(ln, Variable(0)); let node_base_idx = self.idx(ln, Variable::from(0u32));
for var_idx in 0..self.ir.var_kinds.len() { for var_idx in 0..self.ir.var_kinds.len() {
let idx = node_base_idx + var_idx; let idx = node_base_idx + var_idx;
if test(idx) { if test(idx) {
write!(wr, " {:?}", Variable(var_idx as u32))?; write!(wr, " {:?}", Variable::from(var_idx))?;
} }
} }
Ok(()) Ok(())
@ -769,14 +746,14 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
let mut wr = Vec::new(); let mut wr = Vec::new();
{ {
let wr = &mut wr as &mut dyn Write; let wr = &mut wr as &mut dyn Write;
write!(wr, "[ln({:?}) of kind {:?} reads", ln.get(), self.ir.lnk(ln)); write!(wr, "[{:?} of kind {:?} reads", ln, self.ir.lnk(ln));
self.write_vars(wr, ln, |idx| self.rwu_table.get_reader(idx).is_valid()); self.write_vars(wr, ln, |idx| self.rwu_table.get_reader(idx).is_valid());
write!(wr, " writes"); write!(wr, " writes");
self.write_vars(wr, ln, |idx| self.rwu_table.get_writer(idx).is_valid()); self.write_vars(wr, ln, |idx| self.rwu_table.get_writer(idx).is_valid());
write!(wr, " uses"); write!(wr, " uses");
self.write_vars(wr, ln, |idx| self.rwu_table.get_used(idx)); self.write_vars(wr, ln, |idx| self.rwu_table.get_used(idx));
write!(wr, " precedes {:?}]", self.successors[ln.get()]); write!(wr, " precedes {:?}]", self.successors[ln]);
} }
String::from_utf8(wr).unwrap() String::from_utf8(wr).unwrap()
} }
@ -787,7 +764,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
"^^ liveness computation results for body {} (entry={:?})", "^^ liveness computation results for body {} (entry={:?})",
{ {
for ln_idx in 0..self.ir.lnks.len() { for ln_idx in 0..self.ir.lnks.len() {
debug!("{:?}", self.ln_str(LiveNode(ln_idx as u32))); debug!("{:?}", self.ln_str(LiveNode::from(ln_idx)));
} }
hir_id hir_id
}, },
@ -796,7 +773,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
} }
fn init_empty(&mut self, ln: LiveNode, succ_ln: LiveNode) { fn init_empty(&mut self, ln: LiveNode, succ_ln: LiveNode) {
self.successors[ln.get()] = succ_ln; self.successors[ln] = succ_ln;
// It is not necessary to initialize the RWUs here because they are all // It is not necessary to initialize the RWUs here because they are all
// set to INV_INV_FALSE when they are created, and the sets only grow // set to INV_INV_FALSE when they are created, and the sets only grow
@ -805,7 +782,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
fn init_from_succ(&mut self, ln: LiveNode, succ_ln: LiveNode) { fn init_from_succ(&mut self, ln: LiveNode, succ_ln: LiveNode) {
// more efficient version of init_empty() / merge_from_succ() // more efficient version of init_empty() / merge_from_succ()
self.successors[ln.get()] = succ_ln; self.successors[ln] = succ_ln;
self.indices2(ln, succ_ln, |this, idx, succ_idx| { self.indices2(ln, succ_ln, |this, idx, succ_idx| {
this.rwu_table.copy_packed(idx, succ_idx); this.rwu_table.copy_packed(idx, succ_idx);
@ -878,7 +855,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
let mut rwu = self.rwu_table.get(idx); let mut rwu = self.rwu_table.get(idx);
if (acc & ACC_WRITE) != 0 { if (acc & ACC_WRITE) != 0 {
rwu.reader = invalid_node(); rwu.reader = INVALID_NODE;
rwu.writer = ln; rwu.writer = ln;
} }