Rollup merge of #137008 - nnethercote:mv-code-into-rustc_mir_transform, r=oli-obk

Move code into `rustc_mir_transform`

I found two modules in other crates that are better placed in `rustc_mir_transform`, because that's the only crate that uses them.

r? ``@matthewjasper``

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_dataflow/src/drop_flag_effects.rs

@@ -3,7 +3,26 @@ use rustc_middle::mir::{self, Body, Location, Terminator, TerminatorKind};
 use tracing::debug;
 
 use super::move_paths::{InitKind, LookupResult, MoveData, MovePathIndex};
-use crate::elaborate_drops::DropFlagState;
+
+/// The value of an inserted drop flag.
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum DropFlagState {
+    /// The tracked value is initialized and needs to be dropped when leaving its scope.
+    Present,
+
+    /// The tracked value is uninitialized or was moved out of and does not need to be dropped when
+    /// leaving its scope.
+    Absent,
+}
+
+impl DropFlagState {
+    pub fn value(self) -> bool {
+        match self {
+            DropFlagState::Present => true,
+            DropFlagState::Absent => false,
+        }
+    }
+}
 
 pub fn move_path_children_matching<'tcx, F>(
     move_data: &MoveData<'tcx>,

compiler/rustc_mir_dataflow/src/impls/initialized.rs

@@ -9,7 +9,7 @@ use rustc_middle::ty::util::Discr;
 use rustc_middle::ty::{self, TyCtxt};
 use tracing::{debug, instrument};
 
-use crate::elaborate_drops::DropFlagState;
+use crate::drop_flag_effects::DropFlagState;
 use crate::framework::SwitchIntTarget;
 use crate::move_paths::{HasMoveData, InitIndex, InitKind, LookupResult, MoveData, MovePathIndex};
 use crate::{

compiler/rustc_mir_dataflow/src/lib.rs

@@ -15,7 +15,7 @@ use rustc_middle::ty;
 // Please change the public `use` directives cautiously, as they might be used by external tools.
 // See issue #120130.
 pub use self::drop_flag_effects::{
-    drop_flag_effects_for_function_entry, drop_flag_effects_for_location,
+    DropFlagState, drop_flag_effects_for_function_entry, drop_flag_effects_for_location,
     move_path_children_matching, on_all_children_bits, on_lookup_result_bits,
 };
 pub use self::framework::{
@@ -26,7 +26,6 @@ use self::move_paths::MoveData;
 
 pub mod debuginfo;
 mod drop_flag_effects;
-pub mod elaborate_drops;
 mod errors;
 mod framework;
 pub mod impls;

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 rustc_mir_dataflow::elaborate_drops::{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;
@@ -13,29 +12,11 @@ use rustc_span::DUMMY_SP;
 use rustc_span::source_map::Spanned;
 use tracing::{debug, instrument};
 
-/// The value of an inserted drop flag.
+use crate::patch::MirPatch;
-#[derive(Debug, PartialEq, Eq, Copy, Clone)]
-pub enum DropFlagState {
-    /// The tracked value is initialized and needs to be dropped when leaving its scope.
-    Present,
-
-    /// The tracked value is uninitialized or was moved out of and does not need to be dropped when
-    /// leaving its scope.
-    Absent,
-}
-
-impl DropFlagState {
-    pub fn value(self) -> bool {
-        match self {
-            DropFlagState::Present => true,
-            DropFlagState::Absent => false,
-        }
-    }
-}
 
 /// Describes how/if a value should be dropped.
 #[derive(Debug)]
-pub enum DropStyle {
+pub(crate) enum DropStyle {
     /// The value is already dead at the drop location, no drop will be executed.
     Dead,
 
@@ -56,7 +37,7 @@ pub enum DropStyle {
 
 /// Which drop flags to affect/check with an operation.
 #[derive(Debug)]
-pub enum DropFlagMode {
+pub(crate) enum DropFlagMode {
     /// Only affect the top-level drop flag, not that of any contained fields.
     Shallow,
     /// Affect all nested drop flags in addition to the top-level one.
@@ -65,7 +46,7 @@ pub enum DropFlagMode {
 
 /// Describes if unwinding is necessary and where to unwind to if a panic occurs.
 #[derive(Copy, Clone, Debug)]
-pub enum Unwind {
+pub(crate) enum Unwind {
     /// Unwind to this block.
     To(BasicBlock),
     /// Already in an unwind path, any panic will cause an abort.
@@ -98,7 +79,7 @@ impl Unwind {
     }
 }
 
-pub trait DropElaborator<'a, 'tcx>: fmt::Debug {
+pub(crate) trait DropElaborator<'a, 'tcx>: fmt::Debug {
     /// The type representing paths that can be moved out of.
     ///
     /// Users can move out of individual fields of a struct, such as `a.b.c`. This type is used to
@@ -177,7 +158,7 @@ where
 /// value.
 ///
 /// When this returns, the MIR patch in the `elaborator` contains the necessary changes.
-pub fn elaborate_drop<'b, 'tcx, D>(
+pub(crate) fn elaborate_drop<'b, 'tcx, D>(
     elaborator: &mut D,
     source_info: SourceInfo,
     place: Place<'tcx>,

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -3,21 +3,20 @@ 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::elaborate_drops::{
-    DropElaborator, DropFlagMode, DropFlagState, DropStyle, Unwind, elaborate_drop,
-};
 use rustc_mir_dataflow::impls::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
 use rustc_mir_dataflow::move_paths::{LookupResult, MoveData, MovePathIndex};
 use rustc_mir_dataflow::{
-    Analysis, MoveDataTypingEnv, ResultsCursor, on_all_children_bits, on_lookup_result_bits,
+    Analysis, DropFlagState, MoveDataTypingEnv, ResultsCursor, on_all_children_bits,
+    on_lookup_result_bits,
 };
 use rustc_span::Span;
 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

@@ -49,10 +49,12 @@ mod check_pointers;
 mod cost_checker;
 mod cross_crate_inline;
 mod deduce_param_attrs;
+mod elaborate_drop;
 mod errors;
 mod ffi_unwind_calls;
 mod lint;
 mod lint_tail_expr_drop_order;
+mod patch;
 mod shim;
 mod ssa;
 

compiler/rustc_mir_transform/src/match_branches.rs

@@ -2,7 +2,6 @@ use std::iter;
 
 use rustc_abi::Integer;
 use rustc_index::IndexSlice;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
 use rustc_middle::ty::{self, ScalarInt, Ty, TyCtxt};
@@ -10,6 +9,7 @@ use rustc_type_ir::TyKind::*;
 use tracing::instrument;
 
 use super::simplify::simplify_cfg;
+use crate::patch::MirPatch;
 
 pub(super) struct MatchBranchSimplification;
 

compiler/rustc_mir_transform/src/patch.rs

@@ -1,11 +1,13 @@
+use rustc_index::{Idx, IndexVec};
+use rustc_middle::mir::*;
+use rustc_middle::ty::Ty;
+use rustc_span::Span;
 use tracing::debug;
 
-use crate::mir::*;
-
 /// This struct represents a patch to MIR, which can add
 /// new statements and basic blocks and patch over block
 /// terminators.
-pub struct MirPatch<'tcx> {
+pub(crate) struct MirPatch<'tcx> {
     patch_map: IndexVec<BasicBlock, Option<TerminatorKind<'tcx>>>,
     new_blocks: Vec<BasicBlockData<'tcx>>,
     new_statements: Vec<(Location, StatementKind<'tcx>)>,
@@ -22,7 +24,7 @@ pub struct MirPatch<'tcx> {
 }
 
 impl<'tcx> MirPatch<'tcx> {
-    pub fn new(body: &Body<'tcx>) -> Self {
+    pub(crate) fn new(body: &Body<'tcx>) -> Self {
         let mut result = MirPatch {
             patch_map: IndexVec::from_elem(None, &body.basic_blocks),
             new_blocks: vec![],
@@ -69,7 +71,7 @@ impl<'tcx> MirPatch<'tcx> {
         result
     }
 
-    pub fn resume_block(&mut self) -> BasicBlock {
+    pub(crate) fn resume_block(&mut self) -> BasicBlock {
         if let Some(bb) = self.resume_block {
             return bb;
         }
@@ -86,7 +88,7 @@ impl<'tcx> MirPatch<'tcx> {
         bb
     }
 
-    pub fn unreachable_cleanup_block(&mut self) -> BasicBlock {
+    pub(crate) fn unreachable_cleanup_block(&mut self) -> BasicBlock {
         if let Some(bb) = self.unreachable_cleanup_block {
             return bb;
         }
@@ -103,7 +105,7 @@ impl<'tcx> MirPatch<'tcx> {
         bb
     }
 
-    pub fn unreachable_no_cleanup_block(&mut self) -> BasicBlock {
+    pub(crate) fn unreachable_no_cleanup_block(&mut self) -> BasicBlock {
         if let Some(bb) = self.unreachable_no_cleanup_block {
             return bb;
         }
@@ -120,7 +122,7 @@ impl<'tcx> MirPatch<'tcx> {
         bb
     }
 
-    pub fn terminate_block(&mut self, reason: UnwindTerminateReason) -> BasicBlock {
+    pub(crate) fn terminate_block(&mut self, reason: UnwindTerminateReason) -> BasicBlock {
         if let Some((cached_bb, cached_reason)) = self.terminate_block
             && reason == cached_reason
         {
@@ -139,19 +141,11 @@ impl<'tcx> MirPatch<'tcx> {
         bb
     }
 
-    pub fn is_patched(&self, bb: BasicBlock) -> bool {
+    pub(crate) fn is_patched(&self, bb: BasicBlock) -> bool {
         self.patch_map[bb].is_some()
     }
 
-    pub fn terminator_loc(&self, body: &Body<'tcx>, bb: BasicBlock) -> Location {
+    pub(crate) fn new_local_with_info(
-        let offset = match bb.index().checked_sub(body.basic_blocks.len()) {
-            Some(index) => self.new_blocks[index].statements.len(),
-            None => body[bb].statements.len(),
-        };
-        Location { block: bb, statement_index: offset }
-    }
-
-    pub fn new_local_with_info(
         &mut self,
         ty: Ty<'tcx>,
         span: Span,
@@ -165,14 +159,14 @@ impl<'tcx> MirPatch<'tcx> {
         Local::new(index)
     }
 
-    pub fn new_temp(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
+    pub(crate) fn new_temp(&mut self, ty: Ty<'tcx>, span: Span) -> Local {
         let index = self.next_local;
         self.next_local += 1;
         self.new_locals.push(LocalDecl::new(ty, span));
         Local::new(index)
     }
 
-    pub fn new_block(&mut self, data: BasicBlockData<'tcx>) -> BasicBlock {
+    pub(crate) fn new_block(&mut self, data: BasicBlockData<'tcx>) -> BasicBlock {
         let block = BasicBlock::new(self.patch_map.len());
         debug!("MirPatch: new_block: {:?}: {:?}", block, data);
         self.new_blocks.push(data);
@@ -180,22 +174,22 @@ impl<'tcx> MirPatch<'tcx> {
         block
     }
 
-    pub fn patch_terminator(&mut self, block: BasicBlock, new: TerminatorKind<'tcx>) {
+    pub(crate) fn patch_terminator(&mut self, block: BasicBlock, new: TerminatorKind<'tcx>) {
         assert!(self.patch_map[block].is_none());
         debug!("MirPatch: patch_terminator({:?}, {:?})", block, new);
         self.patch_map[block] = Some(new);
     }
 
-    pub fn add_statement(&mut self, loc: Location, stmt: StatementKind<'tcx>) {
+    pub(crate) fn add_statement(&mut self, loc: Location, stmt: StatementKind<'tcx>) {
         debug!("MirPatch: add_statement({:?}, {:?})", loc, stmt);
         self.new_statements.push((loc, stmt));
     }
 
-    pub fn add_assign(&mut self, loc: Location, place: Place<'tcx>, rv: Rvalue<'tcx>) {
+    pub(crate) fn add_assign(&mut self, loc: Location, place: Place<'tcx>, rv: Rvalue<'tcx>) {
         self.add_statement(loc, StatementKind::Assign(Box::new((place, rv))));
     }
 
-    pub fn apply(self, body: &mut Body<'tcx>) {
+    pub(crate) fn apply(self, body: &mut Body<'tcx>) {
         debug!(
             "MirPatch: {:?} new temps, starting from index {}: {:?}",
             self.new_locals.len(),
@@ -241,14 +235,14 @@ impl<'tcx> MirPatch<'tcx> {
         }
     }
 
-    pub fn source_info_for_index(data: &BasicBlockData<'_>, loc: Location) -> SourceInfo {
+    fn source_info_for_index(data: &BasicBlockData<'_>, loc: Location) -> SourceInfo {
         match data.statements.get(loc.statement_index) {
             Some(stmt) => stmt.source_info,
             None => data.terminator().source_info,
         }
     }
 
-    pub fn source_info_for_location(&self, body: &Body<'tcx>, loc: Location) -> SourceInfo {
+    pub(crate) fn source_info_for_location(&self, body: &Body<'tcx>, loc: Location) -> SourceInfo {
         let data = match loc.block.index().checked_sub(body.basic_blocks.len()) {
             Some(new) => &self.new_blocks[new],
             None => &body[loc.block],

compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs

@@ -1,10 +1,11 @@
 use rustc_index::bit_set::DenseBitSet;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use rustc_target::spec::PanicStrategy;
 use tracing::debug;
 
+use crate::patch::MirPatch;
+
 /// A pass that removes noop landing pads and replaces jumps to them with
 /// `UnwindAction::Continue`. This is important because otherwise LLVM generates
 /// terrible code for these.

compiler/rustc_mir_transform/src/shim.rs

@@ -6,7 +6,6 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_index::{Idx, IndexVec};
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::adjustment::PointerCoercion;
@@ -14,11 +13,12 @@ use rustc_middle::ty::{
     self, CoroutineArgs, CoroutineArgsExt, EarlyBinder, GenericArgs, Ty, TyCtxt,
 };
 use rustc_middle::{bug, span_bug};
-use rustc_mir_dataflow::elaborate_drops::{self, DropElaborator, DropFlagMode, DropStyle};
 use rustc_span::source_map::Spanned;
 use rustc_span::{DUMMY_SP, Span};
 use tracing::{debug, instrument};
 
+use crate::elaborate_drop::{DropElaborator, DropFlagMode, DropStyle, Unwind, elaborate_drop};
+use crate::patch::MirPatch;
 use crate::{
     abort_unwinding_calls, add_call_guards, add_moves_for_packed_drops, deref_separator, inline,
     instsimplify, mentioned_items, pass_manager as pm, remove_noop_landing_pads, simplify,
@@ -283,13 +283,13 @@ fn build_drop_shim<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, ty: Option<Ty<'tcx>>)
                 DropShimElaborator { body: &body, patch: MirPatch::new(&body), tcx, typing_env };
             let dropee = tcx.mk_place_deref(dropee_ptr);
             let resume_block = elaborator.patch.resume_block();
-            elaborate_drops::elaborate_drop(
+            elaborate_drop(
                 &mut elaborator,
                 source_info,
                 dropee,
                 (),
                 return_block,
-                elaborate_drops::Unwind::To(resume_block),
+                Unwind::To(resume_block),
                 START_BLOCK,
             );
             elaborator.patch

compiler/rustc_mir_transform/src/sroa.rs

@@ -4,13 +4,14 @@ use rustc_hir::LangItem;
 use rustc_index::IndexVec;
 use rustc_index::bit_set::{DenseBitSet, GrowableBitSet};
 use rustc_middle::bug;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_mir_dataflow::value_analysis::{excluded_locals, iter_fields};
 use tracing::{debug, instrument};
 
+use crate::patch::MirPatch;
+
 pub(super) struct ScalarReplacementOfAggregates;
 
 impl<'tcx> crate::MirPass<'tcx> for ScalarReplacementOfAggregates {

compiler/rustc_mir_transform/src/unreachable_enum_branching.rs

@@ -3,7 +3,6 @@
 use rustc_abi::Variants;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::bug;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::{
     BasicBlock, BasicBlockData, BasicBlocks, Body, Local, Operand, Rvalue, StatementKind,
     TerminatorKind,
@@ -12,6 +11,8 @@ use rustc_middle::ty::layout::TyAndLayout;
 use rustc_middle::ty::{Ty, TyCtxt};
 use tracing::trace;
 
+use crate::patch::MirPatch;
+
 pub(super) struct UnreachableEnumBranching;
 
 fn get_discriminant_local(terminator: &TerminatorKind<'_>) -> Option<Local> {

compiler/rustc_mir_transform/src/unreachable_prop.rs

@@ -6,10 +6,11 @@ use rustc_abi::Size;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::bug;
 use rustc_middle::mir::interpret::Scalar;
-use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
 
+use crate::patch::MirPatch;
+
 pub(super) struct UnreachablePropagation;
 
 impl crate::MirPass<'_> for UnreachablePropagation {