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Auto merge of rust-lang#76896 - spastorino:codegen-inline-fns2, r=dav…
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…idtwco,wesleywiser

Do not make local copies of inline fns in debug mode

r? `@wesleywiser`

cc `@rust-lang/wg-incr-comp`

If this is correct it supersedes rust-lang#76889

Related to rust-lang#54089
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bors committed Jan 8, 2021
2 parents 937f629 + 07a5982 commit ddf2cc7
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Showing 4 changed files with 39 additions and 26 deletions.
40 changes: 18 additions & 22 deletions compiler/rustc_middle/src/mir/mono.rs
Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
use crate::dep_graph::{DepConstructor, DepNode, WorkProduct, WorkProductId};
use crate::ich::{NodeIdHashingMode, StableHashingContext};
use crate::ty::{subst::InternalSubsts, Instance, InstanceDef, SymbolName, TyCtxt};
use rustc_attr::InlineAttr;
use rustc_data_structures::base_n;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::FxHashMap;
Expand Down Expand Up @@ -79,14 +78,6 @@ impl<'tcx> MonoItem<'tcx> {
}

pub fn instantiation_mode(&self, tcx: TyCtxt<'tcx>) -> InstantiationMode {
let generate_cgu_internal_copies = tcx
.sess
.opts
.debugging_opts
.inline_in_all_cgus
.unwrap_or_else(|| tcx.sess.opts.optimize != OptLevel::No)
&& !tcx.sess.link_dead_code();

match *self {
MonoItem::Fn(ref instance) => {
let entry_def_id = tcx.entry_fn(LOCAL_CRATE).map(|(id, _)| id);
Expand All @@ -99,21 +90,26 @@ impl<'tcx> MonoItem<'tcx> {
return InstantiationMode::GloballyShared { may_conflict: false };
}

let generate_cgu_internal_copies = tcx
.sess
.opts
.debugging_opts
.inline_in_all_cgus
.unwrap_or_else(|| tcx.sess.opts.optimize != OptLevel::No)
&& !tcx.sess.link_dead_code();

// At this point we don't have explicit linkage and we're an
// inlined function. If we're inlining into all CGUs then we'll
// be creating a local copy per CGU.
// inlined function. If we should generate local copies for each CGU,
// then return `LocalCopy`, otherwise we'll just generate one copy
// and share it with all CGUs in this crate.
if generate_cgu_internal_copies {
return InstantiationMode::LocalCopy;
}

// Finally, if this is `#[inline(always)]` we're sure to respect
// that with an inline copy per CGU, but otherwise we'll be
// creating one copy of this `#[inline]` function which may
// conflict with upstream crates as it could be an exported
// symbol.
match tcx.codegen_fn_attrs(instance.def_id()).inline {
InlineAttr::Always => InstantiationMode::LocalCopy,
_ => InstantiationMode::GloballyShared { may_conflict: true },
InstantiationMode::LocalCopy
} else {
// Finally, if we've reached this point, then we should optimize for
// compilation speed. In that regard, we will ignore any `#[inline]`
// annotations on the function and simply codegen it as usual. This could
// conflict with upstream crates as it could be an exported symbol.
InstantiationMode::GloballyShared { may_conflict: true }
}
}
MonoItem::Static(..) | MonoItem::GlobalAsm(..) => {
Expand Down
9 changes: 7 additions & 2 deletions src/test/incremental/hygiene/load_cached_hygiene.rs
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
// revisions:rpass1 rpass2
// compile-flags: -Z query-dep-graph
// compile-flags: -Z query-dep-graph -O
// aux-build:cached_hygiene.rs

// This tests the folllowing scenario
Expand All @@ -19,7 +19,12 @@
// the metadata. Specifically, we were not resetting `orig_id`
// for an `EpxnData` generate in the current crate, which would cause
// us to serialize the `ExpnId` pointing to a garbage location in
// the metadata.
// the metadata.o

// NOTE: We're explicitly passing the `-O` optimization flag because if optimizations are not
// enabled, then rustc will ignore the `#[inline(always)]` attribute which means we do not load
// the optimized mir for the unmodified function to be loaded and so the CGU containing that
// function will be reused.

#![feature(rustc_attrs)]

Expand Down
9 changes: 8 additions & 1 deletion src/test/incremental/remapped_paths_cc/main.rs
Original file line number Diff line number Diff line change
@@ -1,11 +1,18 @@
// revisions:rpass1 rpass2 rpass3
// compile-flags: -Z query-dep-graph -g
// compile-flags: -Z query-dep-graph -g -O
// aux-build:extern_crate.rs

// ignore-asmjs wasm2js does not support source maps yet

// This test case makes sure that we detect if paths emitted into debuginfo
// are changed, even when the change happens in an external crate.

// NOTE: We're explicitly passing the `-O` optimization flag because if no optimizations are
// requested, rustc will ignore the `#[inline]` attribute. This is a performance optimization for
// non-optimized builds which causes us to generate fewer copies of inlined functions when
// runtime performance doesn't matter. Without this flag, the function will go into a different
// CGU which can be reused by this crate.

#![feature(rustc_attrs)]

#![rustc_partition_reused(module="main", cfg="rpass2")]
Expand Down
7 changes: 6 additions & 1 deletion src/test/run-make-fulldeps/inline-always-many-cgu/Makefile
Original file line number Diff line number Diff line change
@@ -1,7 +1,12 @@
-include ../tools.mk

all:
$(RUSTC) foo.rs --emit llvm-ir -C codegen-units=2
$(RUSTC) foo.rs --emit llvm-ir -C codegen-units=2 -C opt-level=0
if ![cat $(TMPDIR)/*.ll | $(CGREP) -e '\bcall\b']; then \
echo "not found call instruction when one was expected"; \
exit 1; \
fi
$(RUSTC) foo.rs --emit llvm-ir -C codegen-units=2 -C opt-level=1
if cat $(TMPDIR)/*.ll | $(CGREP) -e '\bcall\b'; then \
echo "found call instruction when one wasn't expected"; \
exit 1; \
Expand Down

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