Move MirPass to rustc_mir_transform.

Because that's now the only crate that uses it.

Moving stuff out of `rustc_middle` is always welcome.

I chose to use `impl crate::MirPass`/`impl crate::MirLint` (with
explicit `crate::`) everywhere because that's the only mention of
`MirPass`/`MirLint` used in all of these files. (Prior to this change,
`MirPass` was mostly imported via `use rustc_middle::mir::*` items.)

Author: nnethercote

compiler/rustc_middle/src/mir/mod.rs

@@ -3,8 +3,6 @@
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/mir/index.html
 
 use std::borrow::Cow;
-use std::cell::RefCell;
-use std::collections::hash_map::Entry;
 use std::fmt::{self, Debug, Formatter};
 use std::ops::{Index, IndexMut};
 use std::{iter, mem};
@@ -26,7 +24,6 @@ use rustc_index::bit_set::BitSet;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
 use rustc_serialize::{Decodable, Encodable};
-use rustc_session::Session;
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::Symbol;
 use rustc_span::{Span, DUMMY_SP};
@@ -106,65 +103,6 @@ impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
     }
 }
 
-thread_local! {
-    static PASS_NAMES: RefCell<FxHashMap<&'static str, &'static str>> = {
-        RefCell::new(FxHashMap::default())
-    };
-}
-
-/// Converts a MIR pass name into a snake case form to match the profiling naming style.
-fn to_profiler_name(type_name: &'static str) -> &'static str {
-    PASS_NAMES.with(|names| match names.borrow_mut().entry(type_name) {
-        Entry::Occupied(e) => *e.get(),
-        Entry::Vacant(e) => {
-            let snake_case: String = type_name
-                .chars()
-                .flat_map(|c| {
-                    if c.is_ascii_uppercase() {
-                        vec!['_', c.to_ascii_lowercase()]
-                    } else if c == '-' {
-                        vec!['_']
-                    } else {
-                        vec![c]
-                    }
-                })
-                .collect();
-            let result = &*String::leak(format!("mir_pass{}", snake_case));
-            e.insert(result);
-            result
-        }
-    })
-}
-
-/// A streamlined trait that you can implement to create a pass; the
-/// pass will be named after the type, and it will consist of a main
-/// loop that goes over each available MIR and applies `run_pass`.
-pub trait MirPass<'tcx> {
-    fn name(&self) -> &'static str {
-        // FIXME Simplify the implementation once more `str` methods get const-stable.
-        // See copypaste in `MirLint`
-        const {
-            let name = std::any::type_name::<Self>();
-            crate::util::common::c_name(name)
-        }
-    }
-
-    fn profiler_name(&self) -> &'static str {
-        to_profiler_name(self.name())
-    }
-
-    /// Returns `true` if this pass is enabled with the current combination of compiler flags.
-    fn is_enabled(&self, _sess: &Session) -> bool {
-        true
-    }
-
-    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>);
-
-    fn is_mir_dump_enabled(&self) -> bool {
-        true
-    }
-}
-
 impl MirPhase {
     /// Gets the index of the current MirPhase within the set of all `MirPhase`s.
     ///

compiler/rustc_middle/src/util/common.rs

@@ -20,19 +20,3 @@ pub fn to_readable_str(mut val: usize) -> String {
 
     groups.join("_")
 }
-
-// const wrapper for `if let Some((_, tail)) = name.rsplit_once(':') { tail } else { name }`
-pub const fn c_name(name: &'static str) -> &'static str {
-    // FIXME Simplify the implementation once more `str` methods get const-stable.
-    // and inline into call site
-    let bytes = name.as_bytes();
-    let mut i = bytes.len();
-    while i > 0 && bytes[i - 1] != b':' {
-        i = i - 1;
-    }
-    let (_, bytes) = bytes.split_at(i);
-    match std::str::from_utf8(bytes) {
-        Ok(name) => name,
-        Err(_) => name,
-    }
-}

compiler/rustc_mir_transform/src/abort_unwinding_calls.rs

@@ -22,7 +22,7 @@ use rustc_target::spec::PanicStrategy;
 #[derive(PartialEq)]
 pub struct AbortUnwindingCalls;
 
-impl<'tcx> MirPass<'tcx> for AbortUnwindingCalls {
+impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let def_id = body.source.def_id();
         let kind = tcx.def_kind(def_id);

compiler/rustc_mir_transform/src/add_call_guards.rs

@@ -30,7 +30,7 @@ pub use self::AddCallGuards::*;
  *
  */
 
-impl<'tcx> MirPass<'tcx> for AddCallGuards {
+impl<'tcx> crate::MirPass<'tcx> for AddCallGuards {
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         self.add_call_guards(body);
     }

compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs

@@ -37,7 +37,7 @@ use crate::util;
 /// blowup.
 pub struct AddMovesForPackedDrops;
 
-impl<'tcx> MirPass<'tcx> for AddMovesForPackedDrops {
+impl<'tcx> crate::MirPass<'tcx> for AddMovesForPackedDrops {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         debug!("add_moves_for_packed_drops({:?} @ {:?})", body.source, body.span);
         add_moves_for_packed_drops(tcx, body);

compiler/rustc_mir_transform/src/add_retag.rs

@@ -48,7 +48,7 @@ fn may_contain_reference<'tcx>(ty: Ty<'tcx>, depth: u32, tcx: TyCtxt<'tcx>) -> b
     }
 }
 
-impl<'tcx> MirPass<'tcx> for AddRetag {
+impl<'tcx> crate::MirPass<'tcx> for AddRetag {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.opts.unstable_opts.mir_emit_retag
     }

compiler/rustc_mir_transform/src/add_subtyping_projections.rs

@@ -62,7 +62,7 @@ pub fn subtype_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     checker.patcher.apply(body);
 }
 
-impl<'tcx> MirPass<'tcx> for Subtyper {
+impl<'tcx> crate::MirPass<'tcx> for Subtyper {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         subtype_finder(tcx, body);
     }

compiler/rustc_mir_transform/src/check_alignment.rs

@@ -9,7 +9,7 @@ use tracing::{debug, trace};
 
 pub struct CheckAlignment;
 
-impl<'tcx> MirPass<'tcx> for CheckAlignment {
+impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
     fn is_enabled(&self, sess: &Session) -> bool {
         // FIXME(#112480) MSVC and rustc disagree on minimum stack alignment on x86 Windows
         if sess.target.llvm_target == "i686-pc-windows-msvc" {

compiler/rustc_mir_transform/src/check_const_item_mutation.rs

@@ -6,11 +6,11 @@ use rustc_session::lint::builtin::CONST_ITEM_MUTATION;
 use rustc_span::def_id::DefId;
 use rustc_span::Span;
 
-use crate::{errors, MirLint};
+use crate::errors;
 
 pub struct CheckConstItemMutation;
 
-impl<'tcx> MirLint<'tcx> for CheckConstItemMutation {
+impl<'tcx> crate::MirLint<'tcx> for CheckConstItemMutation {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
         let mut checker = ConstMutationChecker { body, tcx, target_local: None };
         checker.visit_body(body);

compiler/rustc_mir_transform/src/check_packed_ref.rs

@@ -3,11 +3,11 @@ use rustc_middle::mir::*;
 use rustc_middle::span_bug;
 use rustc_middle::ty::{self, TyCtxt};
 
-use crate::{errors, util, MirLint};
+use crate::{errors, util};
 
 pub struct CheckPackedRef;
 
-impl<'tcx> MirLint<'tcx> for CheckPackedRef {
+impl<'tcx> crate::MirLint<'tcx> for CheckPackedRef {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
         let param_env = tcx.param_env(body.source.def_id());
         let source_info = SourceInfo::outermost(body.span);

compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs

@@ -21,11 +21,9 @@ use rustc_middle::mir::{Body, BorrowKind, CastKind, Rvalue, StatementKind, Termi
 use rustc_middle::ty::adjustment::PointerCoercion;
 use rustc_middle::ty::TyCtxt;
 
-use crate::MirPass;
-
 pub struct CleanupPostBorrowck;
 
-impl<'tcx> MirPass<'tcx> for CleanupPostBorrowck {
+impl<'tcx> crate::MirPass<'tcx> for CleanupPostBorrowck {
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         for basic_block in body.basic_blocks.as_mut() {
             for statement in basic_block.statements.iter_mut() {

compiler/rustc_mir_transform/src/copy_prop.rs

@@ -19,7 +19,7 @@ use crate::ssa::SsaLocals;
 /// We want to replace all those locals by `_a`, either copied or moved.
 pub struct CopyProp;
 
-impl<'tcx> MirPass<'tcx> for CopyProp {
+impl<'tcx> crate::MirPass<'tcx> for CopyProp {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.mir_opt_level() >= 1
     }

compiler/rustc_mir_transform/src/coroutine.rs

@@ -1535,7 +1535,7 @@ fn check_field_tys_sized<'tcx>(
     }
 }
 
-impl<'tcx> MirPass<'tcx> for StateTransform {
+impl<'tcx> crate::MirPass<'tcx> for StateTransform {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let Some(old_yield_ty) = body.yield_ty() else {
             // This only applies to coroutines

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -28,14 +28,13 @@ use tracing::{debug, debug_span, instrument, trace};
 use crate::coverage::counters::{CounterIncrementSite, CoverageCounters};
 use crate::coverage::graph::CoverageGraph;
 use crate::coverage::mappings::ExtractedMappings;
-use crate::MirPass;
 
 /// Inserts `StatementKind::Coverage` statements that either instrument the binary with injected
 /// counters, via intrinsic `llvm.instrprof.increment`, and/or inject metadata used during codegen
 /// to construct the coverage map.
 pub struct InstrumentCoverage;
 
-impl<'tcx> MirPass<'tcx> for InstrumentCoverage {
+impl<'tcx> crate::MirPass<'tcx> for InstrumentCoverage {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.instrument_coverage()
     }

compiler/rustc_mir_transform/src/ctfe_limit.rs

@@ -8,11 +8,9 @@ use rustc_middle::mir::{
 use rustc_middle::ty::TyCtxt;
 use tracing::instrument;
 
-use crate::MirPass;
-
 pub struct CtfeLimit;
 
-impl<'tcx> MirPass<'tcx> for CtfeLimit {
+impl<'tcx> crate::MirPass<'tcx> for CtfeLimit {
     #[instrument(skip(self, _tcx, body))]
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let doms = body.basic_blocks.dominators();

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -28,7 +28,7 @@ const PLACE_LIMIT: usize = 100;
 
 pub struct DataflowConstProp;
 
-impl<'tcx> MirPass<'tcx> for DataflowConstProp {
+impl<'tcx> crate::MirPass<'tcx> for DataflowConstProp {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.mir_opt_level() >= 3
     }

compiler/rustc_mir_transform/src/dead_store_elimination.rs

@@ -132,7 +132,7 @@ pub enum DeadStoreElimination {
     Final,
 }
 
-impl<'tcx> MirPass<'tcx> for DeadStoreElimination {
+impl<'tcx> crate::MirPass<'tcx> for DeadStoreElimination {
     fn name(&self) -> &'static str {
         match self {
             DeadStoreElimination::Initial => "DeadStoreElimination-initial",

compiler/rustc_mir_transform/src/deduplicate_blocks.rs

@@ -15,7 +15,7 @@ use super::simplify::simplify_cfg;
 
 pub struct DeduplicateBlocks;
 
-impl<'tcx> MirPass<'tcx> for DeduplicateBlocks {
+impl<'tcx> crate::MirPass<'tcx> for DeduplicateBlocks {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.mir_opt_level() >= 4
     }

compiler/rustc_mir_transform/src/deref_separator.rs

@@ -78,7 +78,7 @@ pub fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     checker.patcher.apply(body);
 }
 
-impl<'tcx> MirPass<'tcx> for Derefer {
+impl<'tcx> crate::MirPass<'tcx> for Derefer {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         deref_finder(tcx, body);
     }

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -146,11 +146,9 @@ use rustc_mir_dataflow::points::{save_as_intervals, DenseLocationMap, PointIndex
 use rustc_mir_dataflow::Analysis;
 use tracing::{debug, trace};
 
-use crate::MirPass;
-
 pub struct DestinationPropagation;
 
-impl<'tcx> MirPass<'tcx> for DestinationPropagation {
+impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         // For now, only run at MIR opt level 3. Two things need to be changed before this can be
         // turned on by default:

compiler/rustc_mir_transform/src/dump_mir.rs

@@ -7,11 +7,9 @@ use rustc_middle::mir::{write_mir_pretty, Body};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{OutFileName, OutputType};
 
-use crate::MirPass;
-
 pub struct Marker(pub &'static str);
 
-impl<'tcx> MirPass<'tcx> for Marker {
+impl<'tcx> crate::MirPass<'tcx> for Marker {
     fn name(&self) -> &'static str {
         self.0
     }

compiler/rustc_mir_transform/src/early_otherwise_branch.rs

@@ -92,7 +92,7 @@ use super::simplify::simplify_cfg;
 /// ```
 pub struct EarlyOtherwiseBranch;
 
-impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
+impl<'tcx> crate::MirPass<'tcx> for EarlyOtherwiseBranch {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.mir_opt_level() >= 2
     }

compiler/rustc_mir_transform/src/elaborate_box_derefs.rs

@@ -88,7 +88,7 @@ impl<'tcx, 'a> MutVisitor<'tcx> for ElaborateBoxDerefVisitor<'tcx, 'a> {
 
 pub struct ElaborateBoxDerefs;
 
-impl<'tcx> MirPass<'tcx> for ElaborateBoxDerefs {
+impl<'tcx> crate::MirPass<'tcx> for ElaborateBoxDerefs {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         if let Some(def_id) = tcx.lang_items().owned_box() {
             let unique_did = tcx.adt_def(def_id).non_enum_variant().fields[FieldIdx::ZERO].did;

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -49,7 +49,7 @@ use crate::deref_separator::deref_finder;
 /// ```
 pub struct ElaborateDrops;
 
-impl<'tcx> MirPass<'tcx> for ElaborateDrops {
+impl<'tcx> crate::MirPass<'tcx> for ElaborateDrops {
     #[instrument(level = "trace", skip(self, tcx, body))]
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         debug!("elaborate_drops({:?} @ {:?})", body.source, body.span);

compiler/rustc_mir_transform/src/function_item_references.rs

@@ -9,11 +9,11 @@ use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_target::spec::abi::Abi;
 
-use crate::{errors, MirLint};
+use crate::errors;
 
 pub struct FunctionItemReferences;
 
-impl<'tcx> MirLint<'tcx> for FunctionItemReferences {
+impl<'tcx> crate::MirLint<'tcx> for FunctionItemReferences {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
         let mut checker = FunctionItemRefChecker { tcx, body };
         checker.visit_body(body);

compiler/rustc_mir_transform/src/gvn.rs

@@ -111,7 +111,7 @@ use crate::ssa::{AssignedValue, SsaLocals};
 
 pub struct GVN;
 
-impl<'tcx> MirPass<'tcx> for GVN {
+impl<'tcx> crate::MirPass<'tcx> for GVN {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.mir_opt_level() >= 2
     }

compiler/rustc_mir_transform/src/inline.rs

@@ -42,7 +42,7 @@ struct CallSite<'tcx> {
     source_info: SourceInfo,
 }
 
-impl<'tcx> MirPass<'tcx> for Inline {
+impl<'tcx> crate::MirPass<'tcx> for Inline {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         // FIXME(#127234): Coverage instrumentation currently doesn't handle inlined
         // MIR correctly when Modified Condition/Decision Coverage is enabled.

compiler/rustc_mir_transform/src/instsimplify.rs

@@ -27,7 +27,7 @@ impl InstSimplify {
     }
 }
 
-impl<'tcx> MirPass<'tcx> for InstSimplify {
+impl<'tcx> crate::MirPass<'tcx> for InstSimplify {
     fn name(&self) -> &'static str {
         self.name()
     }

compiler/rustc_mir_transform/src/jump_threading.rs

@@ -61,7 +61,7 @@ const MAX_BACKTRACK: usize = 5;
 const MAX_COST: usize = 100;
 const MAX_PLACES: usize = 100;
 
-impl<'tcx> MirPass<'tcx> for JumpThreading {
+impl<'tcx> crate::MirPass<'tcx> for JumpThreading {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
         sess.mir_opt_level() >= 2
     }

compiler/rustc_mir_transform/src/known_panics_lint.rs

@@ -25,11 +25,10 @@ use rustc_target::abi::{Abi, FieldIdx, HasDataLayout, Size, TargetDataLayout, Va
 use tracing::{debug, instrument, trace};
 
 use crate::errors::{AssertLint, AssertLintKind};
-use crate::MirLint;
 
 pub struct KnownPanicsLint;
 
-impl<'tcx> MirLint<'tcx> for KnownPanicsLint {
+impl<'tcx> crate::MirLint<'tcx> for KnownPanicsLint {
     fn run_lint(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
         if body.tainted_by_errors.is_some() {
             return;