Move MirPatch from rustc_middle to rustc_mir_transform.

Because it's only used in `rustc_mir_transform`. (Presumably it is
currently in `rustc_middle` because lots of other MIR-related stuff is,
but that's not a hard requirement.) And because `rustc_middle` is huge
and it's always good to make it smaller.

Author: nnethercote

compiler/rustc_middle/src/mir/mod.rs

@@ -49,7 +49,6 @@ pub mod generic_graphviz;
 pub mod graphviz;
 pub mod interpret;
 pub mod mono;
-pub mod patch;
 pub mod pretty;
 mod query;
 mod statement;

compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs

@@ -1,8 +1,8 @@
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
 use tracing::debug;
 
+use crate::patch::MirPatch;
 use crate::util;
 
 /// This pass moves values being dropped that are within a packed

compiler/rustc_mir_transform/src/add_subtyping_projections.rs

@@ -1,8 +1,9 @@
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
+use crate::patch::MirPatch;
+
 pub(super) struct Subtyper;
 
 struct SubTypeChecker<'a, 'tcx> {

compiler/rustc_mir_transform/src/coroutine.rs

@@ -1061,9 +1061,8 @@ fn insert_switch<'tcx>(
 }
 
 fn elaborate_coroutine_drops<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-    use rustc_middle::mir::patch::MirPatch;
-
     use crate::elaborate_drop::{Unwind, elaborate_drop};
+    use crate::patch::MirPatch;
     use crate::shim::DropShimElaborator;
 
     // Note that `elaborate_drops` only drops the upvars of a coroutine, and

compiler/rustc_mir_transform/src/deref_separator.rs

@@ -1,9 +1,10 @@
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
 use rustc_middle::mir::visit::{MutVisitor, PlaceContext};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 
+use crate::patch::MirPatch;
+
 pub(super) struct Derefer;
 
 struct DerefChecker<'a, 'tcx> {

compiler/rustc_mir_transform/src/early_otherwise_branch.rs

@@ -1,11 +1,11 @@
 use std::fmt::Debug;
 
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
 use tracing::trace;
 
 use super::simplify::simplify_cfg;
+use crate::patch::MirPatch;
 
 /// This pass optimizes something like
 /// ```ignore (syntax-highlighting-only)

compiler/rustc_mir_transform/src/elaborate_box_derefs.rs

@@ -4,12 +4,13 @@
 
 use rustc_abi::FieldIdx;
 use rustc_hir::def_id::DefId;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::MutVisitor;
 use rustc_middle::mir::*;
 use rustc_middle::span_bug;
 use rustc_middle::ty::{Ty, TyCtxt};
 
+use crate::patch::MirPatch;
+
 /// Constructs the types used when accessing a Box's pointer
 fn build_ptr_tys<'tcx>(
     tcx: TyCtxt<'tcx>,

compiler/rustc_mir_transform/src/elaborate_drop.rs

@@ -3,7 +3,6 @@ use std::{fmt, iter, mem};
 use rustc_abi::{FIRST_VARIANT, FieldIdx, VariantIdx};
 use rustc_hir::lang_items::LangItem;
 use rustc_index::Idx;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::span_bug;
 use rustc_middle::ty::adjustment::PointerCoercion;
@@ -13,6 +12,8 @@ use rustc_span::DUMMY_SP;
 use rustc_span::source_map::Spanned;
 use tracing::{debug, instrument};
 
+use crate::patch::MirPatch;
+
 /// Describes how/if a value should be dropped.
 #[derive(Debug)]
 pub(crate) enum DropStyle {

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -3,7 +3,6 @@ use std::fmt;
 use rustc_abi::{FieldIdx, VariantIdx};
 use rustc_index::IndexVec;
 use rustc_index::bit_set::DenseBitSet;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_mir_dataflow::impls::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
@@ -17,6 +16,7 @@ use tracing::{debug, instrument};
 
 use crate::deref_separator::deref_finder;
 use crate::elaborate_drop::{DropElaborator, DropFlagMode, DropStyle, Unwind, elaborate_drop};
+use crate::patch::MirPatch;
 
 /// During MIR building, Drop terminators are inserted in every place where a drop may occur.
 /// However, in this phase, the presence of these terminators does not guarantee that a destructor

compiler/rustc_mir_transform/src/lib.rs

@@ -54,6 +54,7 @@ mod errors;
 mod ffi_unwind_calls;
 mod lint;
 mod lint_tail_expr_drop_order;
+mod patch;
 mod shim;
 mod ssa;