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Introduce a PartitioningCx struct #76694

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Sep 16, 2020
Merged

Introduce a PartitioningCx struct #76694

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32 changes: 16 additions & 16 deletions compiler/rustc_mir/src/monomorphize/partitioning/default.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ use rustc_middle::ty::print::characteristic_def_id_of_type;
use rustc_middle::ty::{self, DefIdTree, InstanceDef, TyCtxt};
use rustc_span::symbol::Symbol;

use super::PartitioningCx;
use crate::monomorphize::collector::InliningMap;
use crate::monomorphize::partitioning::merging;
use crate::monomorphize::partitioning::{
Expand All @@ -22,35 +23,36 @@ pub struct DefaultPartitioning;
impl<'tcx> Partitioner<'tcx> for DefaultPartitioning {
fn place_root_mono_items(
&mut self,
tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
mono_items: &mut dyn Iterator<Item = MonoItem<'tcx>>,
) -> PreInliningPartitioning<'tcx> {
let mut roots = FxHashSet::default();
let mut codegen_units = FxHashMap::default();
let is_incremental_build = tcx.sess.opts.incremental.is_some();
let is_incremental_build = cx.tcx.sess.opts.incremental.is_some();
let mut internalization_candidates = FxHashSet::default();

// Determine if monomorphizations instantiated in this crate will be made
// available to downstream crates. This depends on whether we are in
// share-generics mode and whether the current crate can even have
// downstream crates.
let export_generics = tcx.sess.opts.share_generics() && tcx.local_crate_exports_generics();
let export_generics =
cx.tcx.sess.opts.share_generics() && cx.tcx.local_crate_exports_generics();

let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
let cgu_name_builder = &mut CodegenUnitNameBuilder::new(cx.tcx);
let cgu_name_cache = &mut FxHashMap::default();

for mono_item in mono_items {
match mono_item.instantiation_mode(tcx) {
match mono_item.instantiation_mode(cx.tcx) {
InstantiationMode::GloballyShared { .. } => {}
InstantiationMode::LocalCopy => continue,
}

let characteristic_def_id = characteristic_def_id_of_mono_item(tcx, mono_item);
let characteristic_def_id = characteristic_def_id_of_mono_item(cx.tcx, mono_item);
let is_volatile = is_incremental_build && mono_item.is_generic_fn();

let codegen_unit_name = match characteristic_def_id {
Some(def_id) => compute_codegen_unit_name(
tcx,
cx.tcx,
cgu_name_builder,
def_id,
is_volatile,
Expand All @@ -65,7 +67,7 @@ impl<'tcx> Partitioner<'tcx> for DefaultPartitioning {

let mut can_be_internalized = true;
let (linkage, visibility) = mono_item_linkage_and_visibility(
tcx,
cx.tcx,
&mono_item,
&mut can_be_internalized,
export_generics,
Expand Down Expand Up @@ -97,17 +99,16 @@ impl<'tcx> Partitioner<'tcx> for DefaultPartitioning {

fn merge_codegen_units(
&mut self,
tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
initial_partitioning: &mut PreInliningPartitioning<'tcx>,
target_cgu_count: usize,
) {
merging::merge_codegen_units(tcx, initial_partitioning, target_cgu_count);
merging::merge_codegen_units(cx, initial_partitioning);
}

fn place_inlined_mono_items(
&mut self,
cx: &PartitioningCx<'_, 'tcx>,
initial_partitioning: PreInliningPartitioning<'tcx>,
inlining_map: &InliningMap<'tcx>,
) -> PostInliningPartitioning<'tcx> {
let mut new_partitioning = Vec::new();
let mut mono_item_placements = FxHashMap::default();
Expand All @@ -124,7 +125,7 @@ impl<'tcx> Partitioner<'tcx> for DefaultPartitioning {
// Collect all items that need to be available in this codegen unit.
let mut reachable = FxHashSet::default();
for root in old_codegen_unit.items().keys() {
follow_inlining(*root, inlining_map, &mut reachable);
follow_inlining(*root, cx.inlining_map, &mut reachable);
}

let mut new_codegen_unit = CodegenUnit::new(old_codegen_unit.name());
Expand Down Expand Up @@ -198,9 +199,8 @@ impl<'tcx> Partitioner<'tcx> for DefaultPartitioning {

fn internalize_symbols(
&mut self,
_tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
partitioning: &mut PostInliningPartitioning<'tcx>,
inlining_map: &InliningMap<'tcx>,
) {
if partitioning.codegen_units.len() == 1 {
// Fast path for when there is only one codegen unit. In this case we
Expand All @@ -218,7 +218,7 @@ impl<'tcx> Partitioner<'tcx> for DefaultPartitioning {
// Build a map from every monomorphization to all the monomorphizations that
// reference it.
let mut accessor_map: FxHashMap<MonoItem<'tcx>, Vec<MonoItem<'tcx>>> = Default::default();
inlining_map.iter_accesses(|accessor, accessees| {
cx.inlining_map.iter_accesses(|accessor, accessees| {
for accessee in accessees {
accessor_map.entry(*accessee).or_default().push(accessor);
}
Expand Down
15 changes: 7 additions & 8 deletions compiler/rustc_mir/src/monomorphize/partitioning/merging.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,17 +3,16 @@ use std::cmp;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir::def_id::LOCAL_CRATE;
use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder};
use rustc_middle::ty::TyCtxt;
use rustc_span::symbol::{Symbol, SymbolStr};

use super::PartitioningCx;
use crate::monomorphize::partitioning::PreInliningPartitioning;

pub fn merge_codegen_units<'tcx>(
tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
initial_partitioning: &mut PreInliningPartitioning<'tcx>,
target_cgu_count: usize,
) {
assert!(target_cgu_count >= 1);
assert!(cx.target_cgu_count >= 1);
let codegen_units = &mut initial_partitioning.codegen_units;

// Note that at this point in time the `codegen_units` here may not be in a
Expand All @@ -32,7 +31,7 @@ pub fn merge_codegen_units<'tcx>(
codegen_units.iter().map(|cgu| (cgu.name(), vec![cgu.name().as_str()])).collect();

// Merge the two smallest codegen units until the target size is reached.
while codegen_units.len() > target_cgu_count {
while codegen_units.len() > cx.target_cgu_count {
// Sort small cgus to the back
codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
let mut smallest = codegen_units.pop().unwrap();
Expand All @@ -56,9 +55,9 @@ pub fn merge_codegen_units<'tcx>(
);
}

let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
let cgu_name_builder = &mut CodegenUnitNameBuilder::new(cx.tcx);

if tcx.sess.opts.incremental.is_some() {
if cx.tcx.sess.opts.incremental.is_some() {
// If we are doing incremental compilation, we want CGU names to
// reflect the path of the source level module they correspond to.
// For CGUs that contain the code of multiple modules because of the
Expand All @@ -82,7 +81,7 @@ pub fn merge_codegen_units<'tcx>(

for cgu in codegen_units.iter_mut() {
if let Some(new_cgu_name) = new_cgu_names.get(&cgu.name()) {
if tcx.sess.opts.debugging_opts.human_readable_cgu_names {
if cx.tcx.sess.opts.debugging_opts.human_readable_cgu_names {
cgu.set_name(Symbol::intern(&new_cgu_name));
} else {
// If we don't require CGU names to be human-readable, we
Expand Down
25 changes: 15 additions & 10 deletions compiler/rustc_mir/src/monomorphize/partitioning/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -107,31 +107,35 @@ use rustc_span::symbol::Symbol;
use crate::monomorphize::collector::InliningMap;
use crate::monomorphize::collector::{self, MonoItemCollectionMode};

pub struct PartitioningCx<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
target_cgu_count: usize,
inlining_map: &'a InliningMap<'tcx>,
}

trait Partitioner<'tcx> {
fn place_root_mono_items(
&mut self,
tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
mono_items: &mut dyn Iterator<Item = MonoItem<'tcx>>,
) -> PreInliningPartitioning<'tcx>;

fn merge_codegen_units(
&mut self,
tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
initial_partitioning: &mut PreInliningPartitioning<'tcx>,
target_cgu_count: usize,
);

fn place_inlined_mono_items(
&mut self,
cx: &PartitioningCx<'_, 'tcx>,
initial_partitioning: PreInliningPartitioning<'tcx>,
inlining_map: &InliningMap<'tcx>,
) -> PostInliningPartitioning<'tcx>;

fn internalize_symbols(
&mut self,
tcx: TyCtxt<'tcx>,
cx: &PartitioningCx<'_, 'tcx>,
partitioning: &mut PostInliningPartitioning<'tcx>,
inlining_map: &InliningMap<'tcx>,
);
}

Expand All @@ -156,12 +160,13 @@ pub fn partition<'tcx>(
let _prof_timer = tcx.prof.generic_activity("cgu_partitioning");

let mut partitioner = get_partitioner(tcx);
let cx = &PartitioningCx { tcx, target_cgu_count: max_cgu_count, inlining_map };
// In the first step, we place all regular monomorphizations into their
// respective 'home' codegen unit. Regular monomorphizations are all
// functions and statics defined in the local crate.
let mut initial_partitioning = {
let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_place_roots");
partitioner.place_root_mono_items(tcx, mono_items)
partitioner.place_root_mono_items(cx, mono_items)
};

initial_partitioning.codegen_units.iter_mut().for_each(|cgu| cgu.estimate_size(tcx));
Expand All @@ -171,7 +176,7 @@ pub fn partition<'tcx>(
// Merge until we have at most `max_cgu_count` codegen units.
{
let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_merge_cgus");
partitioner.merge_codegen_units(tcx, &mut initial_partitioning, max_cgu_count);
partitioner.merge_codegen_units(cx, &mut initial_partitioning);
debug_dump(tcx, "POST MERGING:", initial_partitioning.codegen_units.iter());
}

Expand All @@ -181,7 +186,7 @@ pub fn partition<'tcx>(
// local functions the definition of which is marked with `#[inline]`.
let mut post_inlining = {
let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_place_inline_items");
partitioner.place_inlined_mono_items(initial_partitioning, inlining_map)
partitioner.place_inlined_mono_items(cx, initial_partitioning)
};

post_inlining.codegen_units.iter_mut().for_each(|cgu| cgu.estimate_size(tcx));
Expand All @@ -192,7 +197,7 @@ pub fn partition<'tcx>(
// more freedom to optimize.
if !tcx.sess.link_dead_code() {
let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_internalize_symbols");
partitioner.internalize_symbols(tcx, &mut post_inlining, inlining_map);
partitioner.internalize_symbols(cx, &mut post_inlining);
}

// Finally, sort by codegen unit name, so that we get deterministic results.
Expand Down