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Auto merge of #115964 - bjorn3:cgu_reuse_tracker_global_state, r=cjgillot

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Remove cgu_reuse_tracker from Session

This removes a bit of global mutable state.

It will now miss post-lto cgu reuse when ThinLTO determines that a cgu doesn't get changed, but there weren't any tests for this anyway and a test for it would be fragile to the exact implementation of ThinLTO in LLVM.
This commit is contained in:
bors 2023-10-13 00:09:30 +00:00
commit 130ff8cb6c
19 changed files with 274 additions and 322 deletions
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136
compiler/rustc_session/src/cgu_reuse_tracker.rs
View file

@ -1,136 +0,0 @@
//! Some facilities for tracking how codegen-units are reused during incremental
//! compilation. This is used for incremental compilation tests and debug
//! output.
use crate::errors::{CguNotRecorded, IncorrectCguReuseType};
use crate::Session;
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{DiagnosticArgValue, IntoDiagnosticArg};
use rustc_span::{Span, Symbol};
use std::borrow::Cow;
use std::fmt::{self};
use std::sync::{Arc, Mutex};
#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
pub enum CguReuse {
No,
PreLto,
PostLto,
}
impl fmt::Display for CguReuse {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
CguReuse::No => write!(f, "No"),
CguReuse::PreLto => write!(f, "PreLto "),
CguReuse::PostLto => write!(f, "PostLto "),
}
}
}
impl IntoDiagnosticArg for CguReuse {
fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
}
}
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum ComparisonKind {
Exact,
AtLeast,
}
struct TrackerData {
actual_reuse: FxHashMap<String, CguReuse>,
expected_reuse: FxHashMap<String, (String, SendSpan, CguReuse, ComparisonKind)>,
}
// Span does not implement `Send`, so we can't just store it in the shared
// `TrackerData` object. Instead of splitting up `TrackerData` into shared and
// non-shared parts (which would be complicated), we just mark the `Span` here
// explicitly as `Send`. That's safe because the span data here is only ever
// accessed from the main thread.
struct SendSpan(Span);
unsafe impl Send for SendSpan {}
#[derive(Clone)]
pub struct CguReuseTracker {
data: Option<Arc<Mutex<TrackerData>>>,
}
impl CguReuseTracker {
pub fn new() -> CguReuseTracker {
let data =
TrackerData { actual_reuse: Default::default(), expected_reuse: Default::default() };
CguReuseTracker { data: Some(Arc::new(Mutex::new(data))) }
}
pub fn new_disabled() -> CguReuseTracker {
CguReuseTracker { data: None }
}
pub fn set_actual_reuse(&self, cgu_name: &str, kind: CguReuse) {
if let Some(ref data) = self.data {
debug!("set_actual_reuse({cgu_name:?}, {kind:?})");
let prev_reuse = data.lock().unwrap().actual_reuse.insert(cgu_name.to_string(), kind);
if let Some(prev_reuse) = prev_reuse {
// The only time it is legal to overwrite reuse state is when
// we discover during ThinLTO that we can actually reuse the
// post-LTO version of a CGU.
assert_eq!(prev_reuse, CguReuse::PreLto);
}
}
}
pub fn set_expectation(
&self,
cgu_name: Symbol,
cgu_user_name: &str,
error_span: Span,
expected_reuse: CguReuse,
comparison_kind: ComparisonKind,
) {
if let Some(ref data) = self.data {
debug!("set_expectation({cgu_name:?}, {expected_reuse:?}, {comparison_kind:?})");
let mut data = data.lock().unwrap();
data.expected_reuse.insert(
cgu_name.to_string(),
(cgu_user_name.to_string(), SendSpan(error_span), expected_reuse, comparison_kind),
);
}
}
pub fn check_expected_reuse(&self, sess: &Session) {
if let Some(ref data) = self.data {
let data = data.lock().unwrap();
for (cgu_name, &(ref cgu_user_name, ref error_span, expected_reuse, comparison_kind)) in
&data.expected_reuse
{
if let Some(&actual_reuse) = data.actual_reuse.get(cgu_name) {
let (error, at_least) = match comparison_kind {
ComparisonKind::Exact => (expected_reuse != actual_reuse, false),
ComparisonKind::AtLeast => (actual_reuse < expected_reuse, true),
};
if error {
let at_least = if at_least { 1 } else { 0 };
IncorrectCguReuseType {
span: error_span.0,
cgu_user_name,
actual_reuse,
expected_reuse,
at_least,
};
}
} else {
sess.emit_fatal(CguNotRecorded { cgu_user_name, cgu_name });
}
}
}
}
}

19
compiler/rustc_session/src/errors.rs
View file

@ -1,6 +1,5 @@
use std::num::NonZeroU32;
use crate::cgu_reuse_tracker::CguReuse;
use crate::parse::ParseSess;
use rustc_ast::token;
use rustc_ast::util::literal::LitError;
@ -9,24 +8,6 @@ use rustc_macros::Diagnostic;
use rustc_span::{BytePos, Span, Symbol};
use rustc_target::spec::{SplitDebuginfo, StackProtector, TargetTriple};
#[derive(Diagnostic)]
#[diag(session_incorrect_cgu_reuse_type)]
pub struct IncorrectCguReuseType<'a> {
#[primary_span]
pub span: Span,
pub cgu_user_name: &'a str,
pub actual_reuse: CguReuse,
pub expected_reuse: CguReuse,
pub at_least: u8,
}
#[derive(Diagnostic)]
#[diag(session_cgu_not_recorded)]
pub struct CguNotRecorded<'a> {
pub cgu_user_name: &'a str,
pub cgu_name: &'a str,
}
pub struct FeatureGateError {
pub span: MultiSpan,
pub explain: DiagnosticMessage,

1
compiler/rustc_session/src/lib.rs
View file

@ -23,7 +23,6 @@ extern crate tracing;
use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage};
use rustc_fluent_macro::fluent_messages;
pub mod cgu_reuse_tracker;
pub mod utils;
pub use lint::{declare_lint, declare_lint_pass, declare_tool_lint, impl_lint_pass};
pub use rustc_lint_defs as lint;

11
compiler/rustc_session/src/session.rs
View file

@ -1,4 +1,3 @@
use crate::cgu_reuse_tracker::CguReuseTracker;
use crate::code_stats::CodeStats;
pub use crate::code_stats::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo};
use crate::config::{
@ -153,9 +152,6 @@ pub struct Session {
pub io: CompilerIO,
incr_comp_session: OneThread<RefCell<IncrCompSession>>,
/// Used for incremental compilation tests. Will only be populated if
/// `-Zquery-dep-graph` is specified.
pub cgu_reuse_tracker: CguReuseTracker,
/// Used by `-Z self-profile`.
pub prof: SelfProfilerRef,
@ -1431,12 +1427,6 @@ pub fn build_session(
});
let print_fuel = AtomicU64::new(0);
let cgu_reuse_tracker = if sopts.unstable_opts.query_dep_graph {
CguReuseTracker::new()
} else {
CguReuseTracker::new_disabled()
};
let prof = SelfProfilerRef::new(
self_profiler,
sopts.unstable_opts.time_passes.then(|| sopts.unstable_opts.time_passes_format),
@ -1461,7 +1451,6 @@ pub fn build_session(
sysroot,
io,
incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
cgu_reuse_tracker,
prof,
perf_stats: PerfStats {
symbol_hash_time: Lock::new(Duration::from_secs(0)),