diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src')
20 files changed, 920 insertions, 301 deletions
diff --git a/compiler/rustc_mir_transform/src/check_const_item_mutation.rs b/compiler/rustc_mir_transform/src/check_const_item_mutation.rs index 57b24c9c552..b79150737d6 100644 --- a/compiler/rustc_mir_transform/src/check_const_item_mutation.rs +++ b/compiler/rustc_mir_transform/src/check_const_item_mutation.rs @@ -1,11 +1,12 @@ -use rustc_errors::{DiagnosticBuilder, DiagnosticMessage}; +use rustc_hir::HirId; use rustc_middle::mir::visit::Visitor; use rustc_middle::mir::*; use rustc_middle::ty::TyCtxt; use rustc_session::lint::builtin::CONST_ITEM_MUTATION; use rustc_span::def_id::DefId; +use rustc_span::Span; -use crate::MirLint; +use crate::{errors, MirLint}; pub struct CheckConstItemMutation; @@ -58,16 +59,14 @@ impl<'tcx> ConstMutationChecker<'_, 'tcx> { } } - fn lint_const_item_usage( + /// If we should lint on this usage, return the [`HirId`], source [`Span`] + /// and [`Span`] of the const item to use in the lint. + fn should_lint_const_item_usage( &self, place: &Place<'tcx>, const_item: DefId, location: Location, - msg: impl Into<DiagnosticMessage>, - decorate: impl for<'a, 'b> FnOnce( - &'a mut DiagnosticBuilder<'b, ()>, - ) -> &'a mut DiagnosticBuilder<'b, ()>, - ) { + ) -> Option<(HirId, Span, Span)> { // Don't lint on borrowing/assigning when a dereference is involved. // If we 'leave' the temporary via a dereference, we must // be modifying something else @@ -83,16 +82,9 @@ impl<'tcx> ConstMutationChecker<'_, 'tcx> { .assert_crate_local() .lint_root; - self.tcx.struct_span_lint_hir( - CONST_ITEM_MUTATION, - lint_root, - source_info.span, - msg, - |lint| { - decorate(lint) - .span_note(self.tcx.def_span(const_item), "`const` item defined here") - }, - ); + Some((lint_root, source_info.span, self.tcx.def_span(const_item))) + } else { + None } } } @@ -104,10 +96,14 @@ impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> { // Assigning directly to a constant (e.g. `FOO = true;`) is a hard error, // so emitting a lint would be redundant. if !lhs.projection.is_empty() { - if let Some(def_id) = self.is_const_item_without_destructor(lhs.local) { - self.lint_const_item_usage(&lhs, def_id, loc, "attempting to modify a `const` item",|lint| { - lint.note("each usage of a `const` item creates a new temporary; the original `const` item will not be modified") - }) + if let Some(def_id) = self.is_const_item_without_destructor(lhs.local) + && let Some((lint_root, span, item)) = self.should_lint_const_item_usage(&lhs, def_id, loc) { + self.tcx.emit_spanned_lint( + CONST_ITEM_MUTATION, + lint_root, + span, + errors::ConstMutate::Modify { konst: item } + ); } } // We are looking for MIR of the form: @@ -143,17 +139,22 @@ impl<'tcx> Visitor<'tcx> for ConstMutationChecker<'_, 'tcx> { }); let lint_loc = if method_did.is_some() { self.body.terminator_loc(loc.block) } else { loc }; - self.lint_const_item_usage(place, def_id, lint_loc, "taking a mutable reference to a `const` item", |lint| { - lint - .note("each usage of a `const` item creates a new temporary") - .note("the mutable reference will refer to this temporary, not the original `const` item"); - - if let Some((method_did, _substs)) = method_did { - lint.span_note(self.tcx.def_span(method_did), "mutable reference created due to call to this method"); - } - lint - }); + let method_call = if let Some((method_did, _)) = method_did { + Some(self.tcx.def_span(method_did)) + } else { + None + }; + if let Some((lint_root, span, item)) = + self.should_lint_const_item_usage(place, def_id, lint_loc) + { + self.tcx.emit_spanned_lint( + CONST_ITEM_MUTATION, + lint_root, + span, + errors::ConstMutate::MutBorrow { method_call, konst: item }, + ); + } } } self.super_rvalue(rvalue, loc); diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs index b9bc89fcf8f..2e6cf603d59 100644 --- a/compiler/rustc_mir_transform/src/check_packed_ref.rs +++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs @@ -1,10 +1,9 @@ -use rustc_errors::struct_span_err; use rustc_middle::mir::visit::{PlaceContext, Visitor}; use rustc_middle::mir::*; use rustc_middle::ty::{self, TyCtxt}; -use crate::util; use crate::MirLint; +use crate::{errors, util}; pub struct CheckPackedRef; @@ -49,25 +48,7 @@ impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> { // shouldn't do. span_bug!(self.source_info.span, "builtin derive created an unaligned reference"); } else { - struct_span_err!( - self.tcx.sess, - self.source_info.span, - E0793, - "reference to packed field is unaligned" - ) - .note( - "packed structs are only aligned by one byte, and many modern architectures \ - penalize unaligned field accesses" - ) - .note( - "creating a misaligned reference is undefined behavior (even if that \ - reference is never dereferenced)", - ).help( - "copy the field contents to a local variable, or replace the \ - reference with a raw pointer and use `read_unaligned`/`write_unaligned` \ - (loads and stores via `*p` must be properly aligned even when using raw pointers)" - ) - .emit(); + self.tcx.sess.emit_err(errors::UnalignedPackedRef { span: self.source_info.span }); } } } diff --git a/compiler/rustc_mir_transform/src/check_unsafety.rs b/compiler/rustc_mir_transform/src/check_unsafety.rs index ce6d865a7dc..bdb4f20da10 100644 --- a/compiler/rustc_mir_transform/src/check_unsafety.rs +++ b/compiler/rustc_mir_transform/src/check_unsafety.rs @@ -1,5 +1,4 @@ use rustc_data_structures::unord::{UnordItems, UnordSet}; -use rustc_errors::struct_span_err; use rustc_hir as hir; use rustc_hir::def::DefKind; use rustc_hir::def_id::{DefId, LocalDefId}; @@ -15,6 +14,8 @@ use rustc_session::lint::Level; use std::ops::Bound; +use crate::errors; + pub struct UnsafetyChecker<'a, 'tcx> { body: &'a Body<'tcx>, body_did: LocalDefId, @@ -509,21 +510,12 @@ fn unsafety_check_result(tcx: TyCtxt<'_>, def: LocalDefId) -> &UnsafetyCheckResu fn report_unused_unsafe(tcx: TyCtxt<'_>, kind: UnusedUnsafe, id: HirId) { let span = tcx.sess.source_map().guess_head_span(tcx.hir().span(id)); - let msg = "unnecessary `unsafe` block"; - tcx.struct_span_lint_hir(UNUSED_UNSAFE, id, span, msg, |lint| { - lint.span_label(span, msg); - match kind { - UnusedUnsafe::Unused => {} - UnusedUnsafe::InUnsafeBlock(id) => { - lint.span_label( - tcx.sess.source_map().guess_head_span(tcx.hir().span(id)), - "because it's nested under this `unsafe` block", - ); - } - } - - lint - }); + let nested_parent = if let UnusedUnsafe::InUnsafeBlock(id) = kind { + Some(tcx.sess.source_map().guess_head_span(tcx.hir().span(id))) + } else { + None + }; + tcx.emit_spanned_lint(UNUSED_UNSAFE, id, span, errors::UnusedUnsafe { span, nested_parent }); } pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: LocalDefId) { @@ -537,26 +529,11 @@ pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: LocalDefId) { let UnsafetyCheckResult { violations, unused_unsafes, .. } = tcx.unsafety_check_result(def_id); for &UnsafetyViolation { source_info, lint_root, kind, details } in violations.iter() { - let (description, note) = details.description_and_note(); + let details = errors::RequiresUnsafeDetail { violation: details, span: source_info.span }; match kind { UnsafetyViolationKind::General => { - // once - let unsafe_fn_msg = if unsafe_op_in_unsafe_fn_allowed(tcx, lint_root) { - " function or" - } else { - "" - }; - - let mut err = struct_span_err!( - tcx.sess, - source_info.span, - E0133, - "{} is unsafe and requires unsafe{} block", - description, - unsafe_fn_msg, - ); - err.span_label(source_info.span, description).note(note); + let op_in_unsafe_fn_allowed = unsafe_op_in_unsafe_fn_allowed(tcx, lint_root); let note_non_inherited = tcx.hir().parent_iter(lint_root).find(|(id, node)| { if let Node::Expr(block) = node && let ExprKind::Block(block, _) = block.kind @@ -572,22 +549,23 @@ pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: LocalDefId) { false } }); - if let Some((id, _)) = note_non_inherited { - let span = tcx.hir().span(id); - err.span_label( - tcx.sess.source_map().guess_head_span(span), - "items do not inherit unsafety from separate enclosing items", - ); - } - - err.emit(); + let enclosing = if let Some((id, _)) = note_non_inherited { + Some(tcx.sess.source_map().guess_head_span(tcx.hir().span(id))) + } else { + None + }; + tcx.sess.emit_err(errors::RequiresUnsafe { + span: source_info.span, + enclosing, + details, + op_in_unsafe_fn_allowed, + }); } - UnsafetyViolationKind::UnsafeFn => tcx.struct_span_lint_hir( + UnsafetyViolationKind::UnsafeFn => tcx.emit_spanned_lint( UNSAFE_OP_IN_UNSAFE_FN, lint_root, source_info.span, - format!("{} is unsafe and requires unsafe block (error E0133)", description,), - |lint| lint.span_label(source_info.span, description).note(note), + errors::UnsafeOpInUnsafeFn { details }, ), } } diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs index 7f995c69a48..a5d18fff89b 100644 --- a/compiler/rustc_mir_transform/src/const_prop.rs +++ b/compiler/rustc_mir_transform/src/const_prop.rs @@ -806,6 +806,24 @@ impl<'tcx> MutVisitor<'tcx> for ConstPropagator<'_, 'tcx> { } } + fn process_projection_elem( + &mut self, + elem: PlaceElem<'tcx>, + _: Location, + ) -> Option<PlaceElem<'tcx>> { + if let PlaceElem::Index(local) = elem + && let Some(value) = self.get_const(local.into()) + && self.should_const_prop(&value) + && let interpret::Operand::Immediate(interpret::Immediate::Scalar(scalar)) = *value + && let Ok(offset) = scalar.to_target_usize(&self.tcx) + && let Some(min_length) = offset.checked_add(1) + { + Some(PlaceElem::ConstantIndex { offset, min_length, from_end: false }) + } else { + None + } + } + fn visit_assign( &mut self, place: &mut Place<'tcx>, diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs index a4049d08d7b..adb09c509d2 100644 --- a/compiler/rustc_mir_transform/src/const_prop_lint.rs +++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs @@ -1,6 +1,8 @@ //! Propagates constants for early reporting of statically known //! assertion failures +use std::fmt::Debug; + use either::Left; use rustc_const_eval::interpret::Immediate; @@ -17,7 +19,6 @@ use rustc_middle::ty::InternalSubsts; use rustc_middle::ty::{ self, ConstInt, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeVisitableExt, }; -use rustc_session::lint; use rustc_span::Span; use rustc_target::abi::{HasDataLayout, Size, TargetDataLayout}; use rustc_trait_selection::traits; @@ -25,6 +26,7 @@ use rustc_trait_selection::traits; use crate::const_prop::CanConstProp; use crate::const_prop::ConstPropMachine; use crate::const_prop::ConstPropMode; +use crate::errors::AssertLint; use crate::MirLint; /// The maximum number of bytes that we'll allocate space for a local or the return value. @@ -311,18 +313,9 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { } } - fn report_assert_as_lint( - &self, - lint: &'static lint::Lint, - location: Location, - message: &'static str, - panic: AssertKind<impl std::fmt::Debug>, - ) { - let source_info = self.body().source_info(location); + fn report_assert_as_lint(&self, source_info: &SourceInfo, lint: AssertLint<impl Debug>) { if let Some(lint_root) = self.lint_root(*source_info) { - self.tcx.struct_span_lint_hir(lint, lint_root, source_info.span, message, |lint| { - lint.span_label(source_info.span, format!("{:?}", panic)) - }); + self.tcx.emit_spanned_lint(lint.lint(), lint_root, source_info.span, lint); } } @@ -335,11 +328,13 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { // `AssertKind` only has an `OverflowNeg` variant, so make sure that is // appropriate to use. assert_eq!(op, UnOp::Neg, "Neg is the only UnOp that can overflow"); + let source_info = self.body().source_info(location); self.report_assert_as_lint( - lint::builtin::ARITHMETIC_OVERFLOW, - location, - "this arithmetic operation will overflow", - AssertKind::OverflowNeg(val.to_const_int()), + source_info, + AssertLint::ArithmeticOverflow( + source_info.span, + AssertKind::OverflowNeg(val.to_const_int()), + ), ); return None; } @@ -370,23 +365,23 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { let r_bits = r.to_scalar().to_bits(right_size).ok(); if r_bits.map_or(false, |b| b >= left_size.bits() as u128) { debug!("check_binary_op: reporting assert for {:?}", location); + let source_info = self.body().source_info(location); + let panic = AssertKind::Overflow( + op, + match l { + Some(l) => l.to_const_int(), + // Invent a dummy value, the diagnostic ignores it anyway + None => ConstInt::new( + ScalarInt::try_from_uint(1_u8, left_size).unwrap(), + left_ty.is_signed(), + left_ty.is_ptr_sized_integral(), + ), + }, + r.to_const_int(), + ); self.report_assert_as_lint( - lint::builtin::ARITHMETIC_OVERFLOW, - location, - "this arithmetic operation will overflow", - AssertKind::Overflow( - op, - match l { - Some(l) => l.to_const_int(), - // Invent a dummy value, the diagnostic ignores it anyway - None => ConstInt::new( - ScalarInt::try_from_uint(1_u8, left_size).unwrap(), - left_ty.is_signed(), - left_ty.is_ptr_sized_integral(), - ), - }, - r.to_const_int(), - ), + source_info, + AssertLint::ArithmeticOverflow(source_info.span, panic), ); return None; } @@ -398,11 +393,13 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { let (_res, overflow, _ty) = this.ecx.overflowing_binary_op(op, &l, &r)?; Ok(overflow) })? { + let source_info = self.body().source_info(location); self.report_assert_as_lint( - lint::builtin::ARITHMETIC_OVERFLOW, - location, - "this arithmetic operation will overflow", - AssertKind::Overflow(op, l.to_const_int(), r.to_const_int()), + source_info, + AssertLint::ArithmeticOverflow( + source_info.span, + AssertKind::Overflow(op, l.to_const_int(), r.to_const_int()), + ), ); return None; } @@ -543,11 +540,10 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { // Need proper const propagator for these. _ => return None, }; + let source_info = self.body().source_info(location); self.report_assert_as_lint( - lint::builtin::UNCONDITIONAL_PANIC, - location, - "this operation will panic at runtime", - msg, + source_info, + AssertLint::UnconditionalPanic(source_info.span, msg), ); } diff --git a/compiler/rustc_mir_transform/src/copy_prop.rs b/compiler/rustc_mir_transform/src/copy_prop.rs index 3922ed2fbf7..c565d6f13b1 100644 --- a/compiler/rustc_mir_transform/src/copy_prop.rs +++ b/compiler/rustc_mir_transform/src/copy_prop.rs @@ -33,9 +33,8 @@ impl<'tcx> MirPass<'tcx> for CopyProp { } fn propagate_ssa<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { - let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id()); let borrowed_locals = borrowed_locals(body); - let ssa = SsaLocals::new(tcx, param_env, body, &borrowed_locals); + let ssa = SsaLocals::new(body); let fully_moved = fully_moved_locals(&ssa, body); debug!(?fully_moved); @@ -76,7 +75,7 @@ fn propagate_ssa<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { fn fully_moved_locals(ssa: &SsaLocals, body: &Body<'_>) -> BitSet<Local> { let mut fully_moved = BitSet::new_filled(body.local_decls.len()); - for (_, rvalue) in ssa.assignments(body) { + for (_, rvalue, _) in ssa.assignments(body) { let (Rvalue::Use(Operand::Copy(place) | Operand::Move(place)) | Rvalue::CopyForDeref(place)) = rvalue else { continue }; diff --git a/compiler/rustc_mir_transform/src/errors.rs b/compiler/rustc_mir_transform/src/errors.rs new file mode 100644 index 00000000000..602e40d5131 --- /dev/null +++ b/compiler/rustc_mir_transform/src/errors.rs @@ -0,0 +1,245 @@ +use rustc_errors::{ + DecorateLint, DiagnosticBuilder, DiagnosticMessage, EmissionGuarantee, Handler, IntoDiagnostic, +}; +use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic}; +use rustc_middle::mir::{AssertKind, UnsafetyViolationDetails}; +use rustc_session::lint::{self, Lint}; +use rustc_span::Span; + +#[derive(LintDiagnostic)] +pub(crate) enum ConstMutate { + #[diag(mir_transform_const_modify)] + #[note] + Modify { + #[note(mir_transform_const_defined_here)] + konst: Span, + }, + #[diag(mir_transform_const_mut_borrow)] + #[note] + #[note(mir_transform_note2)] + MutBorrow { + #[note(mir_transform_note3)] + method_call: Option<Span>, + #[note(mir_transform_const_defined_here)] + konst: Span, + }, +} + +#[derive(Diagnostic)] +#[diag(mir_transform_unaligned_packed_ref, code = "E0793")] +#[note] +#[note(mir_transform_note_ub)] +#[help] +pub(crate) struct UnalignedPackedRef { + #[primary_span] + pub span: Span, +} + +#[derive(LintDiagnostic)] +#[diag(mir_transform_unused_unsafe)] +pub(crate) struct UnusedUnsafe { + #[label(mir_transform_unused_unsafe)] + pub span: Span, + #[label] + pub nested_parent: Option<Span>, +} + +pub(crate) struct RequiresUnsafe { + pub span: Span, + pub details: RequiresUnsafeDetail, + pub enclosing: Option<Span>, + pub op_in_unsafe_fn_allowed: bool, +} + +// The primary message for this diagnostic should be '{$label} is unsafe and...', +// so we need to eagerly translate the label here, which isn't supported by the derive API +// We could also exhaustively list out the primary messages for all unsafe violations, +// but this would result in a lot of duplication. +impl<'sess, G: EmissionGuarantee> IntoDiagnostic<'sess, G> for RequiresUnsafe { + #[track_caller] + fn into_diagnostic(self, handler: &'sess Handler) -> DiagnosticBuilder<'sess, G> { + let mut diag = + handler.struct_diagnostic(crate::fluent_generated::mir_transform_requires_unsafe); + diag.code(rustc_errors::DiagnosticId::Error("E0133".to_string())); + diag.set_span(self.span); + diag.span_label(self.span, self.details.label()); + diag.note(self.details.note()); + let desc = handler.eagerly_translate_to_string(self.details.label(), [].into_iter()); + diag.set_arg("details", desc); + diag.set_arg("op_in_unsafe_fn_allowed", self.op_in_unsafe_fn_allowed); + if let Some(sp) = self.enclosing { + diag.span_label(sp, crate::fluent_generated::mir_transform_not_inherited); + } + diag + } +} + +#[derive(Copy, Clone)] +pub(crate) struct RequiresUnsafeDetail { + pub span: Span, + pub violation: UnsafetyViolationDetails, +} + +impl RequiresUnsafeDetail { + fn note(self) -> DiagnosticMessage { + use UnsafetyViolationDetails::*; + match self.violation { + CallToUnsafeFunction => crate::fluent_generated::mir_transform_call_to_unsafe_note, + UseOfInlineAssembly => crate::fluent_generated::mir_transform_use_of_asm_note, + InitializingTypeWith => { + crate::fluent_generated::mir_transform_initializing_valid_range_note + } + CastOfPointerToInt => crate::fluent_generated::mir_transform_const_ptr2int_note, + UseOfMutableStatic => crate::fluent_generated::mir_transform_use_of_static_mut_note, + UseOfExternStatic => crate::fluent_generated::mir_transform_use_of_extern_static_note, + DerefOfRawPointer => crate::fluent_generated::mir_transform_deref_ptr_note, + AccessToUnionField => crate::fluent_generated::mir_transform_union_access_note, + MutationOfLayoutConstrainedField => { + crate::fluent_generated::mir_transform_mutation_layout_constrained_note + } + BorrowOfLayoutConstrainedField => { + crate::fluent_generated::mir_transform_mutation_layout_constrained_borrow_note + } + CallToFunctionWith => crate::fluent_generated::mir_transform_target_feature_call_note, + } + } + + fn label(self) -> DiagnosticMessage { + use UnsafetyViolationDetails::*; + match self.violation { + CallToUnsafeFunction => crate::fluent_generated::mir_transform_call_to_unsafe_label, + UseOfInlineAssembly => crate::fluent_generated::mir_transform_use_of_asm_label, + InitializingTypeWith => { + crate::fluent_generated::mir_transform_initializing_valid_range_label + } + CastOfPointerToInt => crate::fluent_generated::mir_transform_const_ptr2int_label, + UseOfMutableStatic => crate::fluent_generated::mir_transform_use_of_static_mut_label, + UseOfExternStatic => crate::fluent_generated::mir_transform_use_of_extern_static_label, + DerefOfRawPointer => crate::fluent_generated::mir_transform_deref_ptr_label, + AccessToUnionField => crate::fluent_generated::mir_transform_union_access_label, + MutationOfLayoutConstrainedField => { + crate::fluent_generated::mir_transform_mutation_layout_constrained_label + } + BorrowOfLayoutConstrainedField => { + crate::fluent_generated::mir_transform_mutation_layout_constrained_borrow_label + } + CallToFunctionWith => crate::fluent_generated::mir_transform_target_feature_call_label, + } + } +} + +pub(crate) struct UnsafeOpInUnsafeFn { + pub details: RequiresUnsafeDetail, +} + +impl<'a> DecorateLint<'a, ()> for UnsafeOpInUnsafeFn { + #[track_caller] + fn decorate_lint<'b>( + self, + diag: &'b mut DiagnosticBuilder<'a, ()>, + ) -> &'b mut DiagnosticBuilder<'a, ()> { + let desc = diag + .handler() + .expect("lint should not yet be emitted") + .eagerly_translate_to_string(self.details.label(), [].into_iter()); + diag.set_arg("details", desc); + diag.span_label(self.details.span, self.details.label()); + diag.note(self.details.note()); + diag + } + + fn msg(&self) -> DiagnosticMessage { + crate::fluent_generated::mir_transform_unsafe_op_in_unsafe_fn + } +} + +pub(crate) enum AssertLint<P> { + ArithmeticOverflow(Span, AssertKind<P>), + UnconditionalPanic(Span, AssertKind<P>), +} + +impl<'a, P: std::fmt::Debug> DecorateLint<'a, ()> for AssertLint<P> { + fn decorate_lint<'b>( + self, + diag: &'b mut DiagnosticBuilder<'a, ()>, + ) -> &'b mut DiagnosticBuilder<'a, ()> { + diag.span_label(self.span(), format!("{:?}", self.panic())); + diag + } + + fn msg(&self) -> DiagnosticMessage { + match self { + AssertLint::ArithmeticOverflow(..) => { + crate::fluent_generated::mir_transform_arithmetic_overflow + } + AssertLint::UnconditionalPanic(..) => { + crate::fluent_generated::mir_transform_operation_will_panic + } + } + } +} + +impl<P> AssertLint<P> { + pub fn lint(&self) -> &'static Lint { + match self { + AssertLint::ArithmeticOverflow(..) => lint::builtin::ARITHMETIC_OVERFLOW, + AssertLint::UnconditionalPanic(..) => lint::builtin::UNCONDITIONAL_PANIC, + } + } + pub fn span(&self) -> Span { + match self { + AssertLint::ArithmeticOverflow(sp, _) | AssertLint::UnconditionalPanic(sp, _) => *sp, + } + } + pub fn panic(&self) -> &AssertKind<P> { + match self { + AssertLint::ArithmeticOverflow(_, p) | AssertLint::UnconditionalPanic(_, p) => p, + } + } +} + +#[derive(LintDiagnostic)] +#[diag(mir_transform_ffi_unwind_call)] +pub(crate) struct FfiUnwindCall { + #[label(mir_transform_ffi_unwind_call)] + pub span: Span, + pub foreign: bool, +} + +#[derive(LintDiagnostic)] +#[diag(mir_transform_fn_item_ref)] +pub(crate) struct FnItemRef { + #[suggestion(code = "{sugg}", applicability = "unspecified")] + pub span: Span, + pub sugg: String, + pub ident: String, +} + +#[derive(LintDiagnostic)] +#[diag(mir_transform_must_not_suspend)] +pub(crate) struct MustNotSupend<'a> { + #[label] + pub yield_sp: Span, + #[subdiagnostic] + pub reason: Option<MustNotSuspendReason>, + #[help] + pub src_sp: Span, + pub pre: &'a str, + pub def_path: String, + pub post: &'a str, +} + +#[derive(Subdiagnostic)] +#[note(mir_transform_note)] +pub(crate) struct MustNotSuspendReason { + #[primary_span] + pub span: Span, + pub reason: String, +} + +#[derive(Diagnostic)] +#[diag(mir_transform_simd_shuffle_last_const)] +pub(crate) struct SimdShuffleLastConst { + #[primary_span] + pub span: Span, +} diff --git a/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs b/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs index db68adc8bc9..ac1de989a72 100644 --- a/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs +++ b/compiler/rustc_mir_transform/src/ffi_unwind_calls.rs @@ -8,6 +8,8 @@ use rustc_session::lint::builtin::FFI_UNWIND_CALLS; use rustc_target::spec::abi::Abi; use rustc_target::spec::PanicStrategy; +use crate::errors; + fn abi_can_unwind(abi: Abi) -> bool { use Abi::*; match abi { @@ -107,13 +109,13 @@ fn has_ffi_unwind_calls(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> bool { .lint_root; let span = terminator.source_info.span; - let msg = match fn_def_id { - Some(_) => "call to foreign function with FFI-unwind ABI", - None => "call to function pointer with FFI-unwind ABI", - }; - tcx.struct_span_lint_hir(FFI_UNWIND_CALLS, lint_root, span, msg, |lint| { - lint.span_label(span, msg) - }); + let foreign = fn_def_id.is_some(); + tcx.emit_spanned_lint( + FFI_UNWIND_CALLS, + lint_root, + span, + errors::FfiUnwindCall { span, foreign }, + ); tainted = true; } diff --git a/compiler/rustc_mir_transform/src/function_item_references.rs b/compiler/rustc_mir_transform/src/function_item_references.rs index f26c6de9648..5989dbebf2d 100644 --- a/compiler/rustc_mir_transform/src/function_item_references.rs +++ b/compiler/rustc_mir_transform/src/function_item_references.rs @@ -1,5 +1,4 @@ use itertools::Itertools; -use rustc_errors::Applicability; use rustc_hir::def_id::DefId; use rustc_middle::mir::visit::Visitor; use rustc_middle::mir::*; @@ -8,7 +7,7 @@ use rustc_session::lint::builtin::FUNCTION_ITEM_REFERENCES; use rustc_span::{symbol::sym, Span}; use rustc_target::spec::abi::Abi; -use crate::MirLint; +use crate::{errors, MirLint}; pub struct FunctionItemReferences; @@ -174,27 +173,21 @@ impl<'tcx> FunctionItemRefChecker<'_, 'tcx> { let num_args = fn_sig.inputs().map_bound(|inputs| inputs.len()).skip_binder(); let variadic = if fn_sig.c_variadic() { ", ..." } else { "" }; let ret = if fn_sig.output().skip_binder().is_unit() { "" } else { " -> _" }; - self.tcx.struct_span_lint_hir( + let sugg = format!( + "{} as {}{}fn({}{}){}", + if params.is_empty() { ident.clone() } else { format!("{}::<{}>", ident, params) }, + unsafety, + abi, + vec!["_"; num_args].join(", "), + variadic, + ret, + ); + + self.tcx.emit_spanned_lint( FUNCTION_ITEM_REFERENCES, lint_root, span, - "taking a reference to a function item does not give a function pointer", - |lint| { - lint.span_suggestion( - span, - format!("cast `{}` to obtain a function pointer", ident), - format!( - "{} as {}{}fn({}{}){}", - if params.is_empty() { ident } else { format!("{}::<{}>", ident, params) }, - unsafety, - abi, - vec!["_"; num_args].join(", "), - variadic, - ret, - ), - Applicability::Unspecified, - ) - }, + errors::FnItemRef { span, sugg, ident }, ); } } diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs index 9e16c400f14..c9144729145 100644 --- a/compiler/rustc_mir_transform/src/generator.rs +++ b/compiler/rustc_mir_transform/src/generator.rs @@ -51,6 +51,7 @@ //! Otherwise it drops all the values in scope at the last suspension point. use crate::deref_separator::deref_finder; +use crate::errors; use crate::simplify; use crate::MirPass; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; @@ -1891,36 +1892,21 @@ fn check_must_not_suspend_def( data: SuspendCheckData<'_>, ) -> bool { if let Some(attr) = tcx.get_attr(def_id, sym::must_not_suspend) { - let msg = rustc_errors::DelayDm(|| { - format!( - "{}`{}`{} held across a suspend point, but should not be", - data.descr_pre, - tcx.def_path_str(def_id), - data.descr_post, - ) + let reason = attr.value_str().map(|s| errors::MustNotSuspendReason { + span: data.source_span, + reason: s.as_str().to_string(), }); - tcx.struct_span_lint_hir( + tcx.emit_spanned_lint( rustc_session::lint::builtin::MUST_NOT_SUSPEND, hir_id, data.source_span, - msg, - |lint| { - // add span pointing to the offending yield/await - lint.span_label(data.yield_span, "the value is held across this suspend point"); - - // Add optional reason note - if let Some(note) = attr.value_str() { - // FIXME(guswynn): consider formatting this better - lint.span_note(data.source_span, note.as_str()); - } - - // Add some quick suggestions on what to do - // FIXME: can `drop` work as a suggestion here as well? - lint.span_help( - data.source_span, - "consider using a block (`{ ... }`) \ - to shrink the value's scope, ending before the suspend point", - ) + errors::MustNotSupend { + yield_sp: data.yield_span, + reason, + src_sp: data.source_span, + pre: data.descr_pre, + def_path: tcx.def_path_str(def_id), + post: data.descr_post, }, ); diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs index 71bdfd5aae1..ece20d8d3e6 100644 --- a/compiler/rustc_mir_transform/src/inline.rs +++ b/compiler/rustc_mir_transform/src/inline.rs @@ -180,7 +180,7 @@ impl<'tcx> Inliner<'tcx> { let Ok(callee_body) = callsite.callee.try_subst_mir_and_normalize_erasing_regions( self.tcx, self.param_env, - callee_body.clone(), + ty::EarlyBinder(callee_body.clone()), ) else { return Err("failed to normalize callee body"); }; @@ -444,7 +444,9 @@ impl<'tcx> Inliner<'tcx> { work_list.push(target); // If the place doesn't actually need dropping, treat it like a regular goto. - let ty = callsite.callee.subst_mir(self.tcx, &place.ty(callee_body, tcx).ty); + let ty = callsite + .callee + .subst_mir(self.tcx, ty::EarlyBinder(&place.ty(callee_body, tcx).ty)); if ty.needs_drop(tcx, self.param_env) && let UnwindAction::Cleanup(unwind) = unwind { work_list.push(unwind); } @@ -788,7 +790,9 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> { match terminator.kind { TerminatorKind::Drop { ref place, unwind, .. } => { // If the place doesn't actually need dropping, treat it like a regular goto. - let ty = self.instance.subst_mir(tcx, &place.ty(self.callee_body, tcx).ty); + let ty = self + .instance + .subst_mir(tcx, ty::EarlyBinder(&place.ty(self.callee_body, tcx).ty)); if ty.needs_drop(tcx, self.param_env) { self.cost += CALL_PENALTY; if let UnwindAction::Cleanup(_) = unwind { @@ -799,7 +803,7 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> { } } TerminatorKind::Call { func: Operand::Constant(ref f), unwind, .. } => { - let fn_ty = self.instance.subst_mir(tcx, &f.literal.ty()); + let fn_ty = self.instance.subst_mir(tcx, ty::EarlyBinder(&f.literal.ty())); self.cost += if let ty::FnDef(def_id, _) = *fn_ty.kind() && tcx.is_intrinsic(def_id) { // Don't give intrinsics the extra penalty for calls INSTR_COST diff --git a/compiler/rustc_mir_transform/src/inline/cycle.rs b/compiler/rustc_mir_transform/src/inline/cycle.rs index 6046c3876be..1ccf06f6153 100644 --- a/compiler/rustc_mir_transform/src/inline/cycle.rs +++ b/compiler/rustc_mir_transform/src/inline/cycle.rs @@ -44,7 +44,11 @@ pub(crate) fn mir_callgraph_reachable<'tcx>( ) -> bool { trace!(%caller); for &(callee, substs) in tcx.mir_inliner_callees(caller.def) { - let Ok(substs) = caller.try_subst_mir_and_normalize_erasing_regions(tcx, param_env, substs) else { + let Ok(substs) = caller.try_subst_mir_and_normalize_erasing_regions( + tcx, + param_env, + ty::EarlyBinder(substs), + ) else { trace!(?caller, ?param_env, ?substs, "cannot normalize, skipping"); continue; }; diff --git a/compiler/rustc_mir_transform/src/instcombine.rs b/compiler/rustc_mir_transform/src/instsimplify.rs index 432852a1fdd..6bff535586a 100644 --- a/compiler/rustc_mir_transform/src/instcombine.rs +++ b/compiler/rustc_mir_transform/src/instsimplify.rs @@ -1,6 +1,6 @@ //! Performs various peephole optimizations. -use crate::simplify::combine_duplicate_switch_targets; +use crate::simplify::simplify_duplicate_switch_targets; use crate::MirPass; use rustc_hir::Mutability; use rustc_middle::mir::*; @@ -10,15 +10,15 @@ use rustc_middle::ty::{self, ParamEnv, SubstsRef, Ty, TyCtxt}; use rustc_span::symbol::Symbol; use rustc_target::abi::FieldIdx; -pub struct InstCombine; +pub struct InstSimplify; -impl<'tcx> MirPass<'tcx> for InstCombine { +impl<'tcx> MirPass<'tcx> for InstSimplify { fn is_enabled(&self, sess: &rustc_session::Session) -> bool { sess.mir_opt_level() > 0 } fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { - let ctx = InstCombineContext { + let ctx = InstSimplifyContext { tcx, local_decls: &body.local_decls, param_env: tcx.param_env_reveal_all_normalized(body.source.def_id()), @@ -27,43 +27,43 @@ impl<'tcx> MirPass<'tcx> for InstCombine { for statement in block.statements.iter_mut() { match statement.kind { StatementKind::Assign(box (_place, ref mut rvalue)) => { - ctx.combine_bool_cmp(&statement.source_info, rvalue); - ctx.combine_ref_deref(&statement.source_info, rvalue); - ctx.combine_len(&statement.source_info, rvalue); - ctx.combine_cast(&statement.source_info, rvalue); + ctx.simplify_bool_cmp(&statement.source_info, rvalue); + ctx.simplify_ref_deref(&statement.source_info, rvalue); + ctx.simplify_len(&statement.source_info, rvalue); + ctx.simplify_cast(&statement.source_info, rvalue); } _ => {} } } - ctx.combine_primitive_clone( + ctx.simplify_primitive_clone( &mut block.terminator.as_mut().unwrap(), &mut block.statements, ); - ctx.combine_intrinsic_assert( + ctx.simplify_intrinsic_assert( &mut block.terminator.as_mut().unwrap(), &mut block.statements, ); - combine_duplicate_switch_targets(block.terminator.as_mut().unwrap()); + simplify_duplicate_switch_targets(block.terminator.as_mut().unwrap()); } } } -struct InstCombineContext<'tcx, 'a> { +struct InstSimplifyContext<'tcx, 'a> { tcx: TyCtxt<'tcx>, local_decls: &'a LocalDecls<'tcx>, param_env: ParamEnv<'tcx>, } -impl<'tcx> InstCombineContext<'tcx, '_> { - fn should_combine(&self, source_info: &SourceInfo, rvalue: &Rvalue<'tcx>) -> bool { +impl<'tcx> InstSimplifyContext<'tcx, '_> { + fn should_simplify(&self, source_info: &SourceInfo, rvalue: &Rvalue<'tcx>) -> bool { self.tcx.consider_optimizing(|| { - format!("InstCombine - Rvalue: {:?} SourceInfo: {:?}", rvalue, source_info) + format!("InstSimplify - Rvalue: {:?} SourceInfo: {:?}", rvalue, source_info) }) } /// Transform boolean comparisons into logical operations. - fn combine_bool_cmp(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { + fn simplify_bool_cmp(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { match rvalue { Rvalue::BinaryOp(op @ (BinOp::Eq | BinOp::Ne), box (a, b)) => { let new = match (op, self.try_eval_bool(a), self.try_eval_bool(b)) { @@ -94,7 +94,7 @@ impl<'tcx> InstCombineContext<'tcx, '_> { _ => None, }; - if let Some(new) = new && self.should_combine(source_info, rvalue) { + if let Some(new) = new && self.should_simplify(source_info, rvalue) { *rvalue = new; } } @@ -109,14 +109,14 @@ impl<'tcx> InstCombineContext<'tcx, '_> { } /// Transform "&(*a)" ==> "a". - fn combine_ref_deref(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { + fn simplify_ref_deref(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { if let Rvalue::Ref(_, _, place) = rvalue { if let Some((base, ProjectionElem::Deref)) = place.as_ref().last_projection() { if rvalue.ty(self.local_decls, self.tcx) != base.ty(self.local_decls, self.tcx).ty { return; } - if !self.should_combine(source_info, rvalue) { + if !self.should_simplify(source_info, rvalue) { return; } @@ -129,11 +129,11 @@ impl<'tcx> InstCombineContext<'tcx, '_> { } /// Transform "Len([_; N])" ==> "N". - fn combine_len(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { + fn simplify_len(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { if let Rvalue::Len(ref place) = *rvalue { let place_ty = place.ty(self.local_decls, self.tcx).ty; if let ty::Array(_, len) = *place_ty.kind() { - if !self.should_combine(source_info, rvalue) { + if !self.should_simplify(source_info, rvalue) { return; } @@ -144,7 +144,7 @@ impl<'tcx> InstCombineContext<'tcx, '_> { } } - fn combine_cast(&self, _source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { + fn simplify_cast(&self, _source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) { if let Rvalue::Cast(kind, operand, cast_ty) = rvalue { let operand_ty = operand.ty(self.local_decls, self.tcx); if operand_ty == *cast_ty { @@ -196,7 +196,7 @@ impl<'tcx> InstCombineContext<'tcx, '_> { } } - fn combine_primitive_clone( + fn simplify_primitive_clone( &self, terminator: &mut Terminator<'tcx>, statements: &mut Vec<Statement<'tcx>>, @@ -239,7 +239,7 @@ impl<'tcx> InstCombineContext<'tcx, '_> { if !self.tcx.consider_optimizing(|| { format!( - "InstCombine - Call: {:?} SourceInfo: {:?}", + "InstSimplify - Call: {:?} SourceInfo: {:?}", (fn_def_id, fn_substs), terminator.source_info ) @@ -262,7 +262,7 @@ impl<'tcx> InstCombineContext<'tcx, '_> { terminator.kind = TerminatorKind::Goto { target: destination_block }; } - fn combine_intrinsic_assert( + fn simplify_intrinsic_assert( &self, terminator: &mut Terminator<'tcx>, _statements: &mut Vec<Statement<'tcx>>, diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs index 8d9a22ea30d..277237a5515 100644 --- a/compiler/rustc_mir_transform/src/lib.rs +++ b/compiler/rustc_mir_transform/src/lib.rs @@ -1,4 +1,6 @@ #![allow(rustc::potential_query_instability)] +#![deny(rustc::untranslatable_diagnostic)] +#![deny(rustc::diagnostic_outside_of_impl)] #![feature(box_patterns)] #![feature(drain_filter)] #![feature(let_chains)] @@ -69,11 +71,12 @@ pub mod dump_mir; mod early_otherwise_branch; mod elaborate_box_derefs; mod elaborate_drops; +mod errors; mod ffi_unwind_calls; mod function_item_references; mod generator; mod inline; -mod instcombine; +mod instsimplify; mod large_enums; mod lower_intrinsics; mod lower_slice_len; @@ -81,6 +84,7 @@ mod match_branches; mod multiple_return_terminators; mod normalize_array_len; mod nrvo; +mod ref_prop; mod remove_noop_landing_pads; mod remove_storage_markers; mod remove_uninit_drops; @@ -105,6 +109,11 @@ use rustc_const_eval::transform::promote_consts; use rustc_const_eval::transform::validate; use rustc_mir_dataflow::rustc_peek; +use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage}; +use rustc_fluent_macro::fluent_messages; + +fluent_messages! { "../messages.ftl" } + pub fn provide(providers: &mut Providers) { check_unsafety::provide(providers); coverage::query::provide(providers); @@ -547,10 +556,11 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { &match_branches::MatchBranchSimplification, // inst combine is after MatchBranchSimplification to clean up Ne(_1, false) &multiple_return_terminators::MultipleReturnTerminators, - &instcombine::InstCombine, + &instsimplify::InstSimplify, &separate_const_switch::SeparateConstSwitch, &simplify::SimplifyLocals::BeforeConstProp, ©_prop::CopyProp, + &ref_prop::ReferencePropagation, &const_prop::ConstProp, &dataflow_const_prop::DataflowConstProp, // diff --git a/compiler/rustc_mir_transform/src/lower_intrinsics.rs b/compiler/rustc_mir_transform/src/lower_intrinsics.rs index 69ba4840146..dae01e41e5f 100644 --- a/compiler/rustc_mir_transform/src/lower_intrinsics.rs +++ b/compiler/rustc_mir_transform/src/lower_intrinsics.rs @@ -1,6 +1,6 @@ //! Lowers intrinsic calls -use crate::MirPass; +use crate::{errors, MirPass}; use rustc_middle::mir::*; use rustc_middle::ty::subst::SubstsRef; use rustc_middle::ty::{self, Ty, TyCtxt}; @@ -310,11 +310,7 @@ fn resolve_rust_intrinsic<'tcx>( } fn validate_simd_shuffle<'tcx>(tcx: TyCtxt<'tcx>, args: &[Operand<'tcx>], span: Span) { - match &args[2] { - Operand::Constant(_) => {} // all good - _ => { - let msg = "last argument of `simd_shuffle` is required to be a `const` item"; - tcx.sess.span_err(span, msg); - } + if !matches!(args[2], Operand::Constant(_)) { + tcx.sess.emit_err(errors::SimdShuffleLastConst { span }); } } diff --git a/compiler/rustc_mir_transform/src/normalize_array_len.rs b/compiler/rustc_mir_transform/src/normalize_array_len.rs index b3b831bb4ab..3d61d33ce35 100644 --- a/compiler/rustc_mir_transform/src/normalize_array_len.rs +++ b/compiler/rustc_mir_transform/src/normalize_array_len.rs @@ -7,7 +7,6 @@ use rustc_index::IndexVec; use rustc_middle::mir::visit::*; use rustc_middle::mir::*; use rustc_middle::ty::{self, TyCtxt}; -use rustc_mir_dataflow::impls::borrowed_locals; pub struct NormalizeArrayLen; @@ -24,9 +23,7 @@ impl<'tcx> MirPass<'tcx> for NormalizeArrayLen { } fn normalize_array_len_calls<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { - let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id()); - let borrowed_locals = borrowed_locals(body); - let ssa = SsaLocals::new(tcx, param_env, body, &borrowed_locals); + let ssa = SsaLocals::new(body); let slice_lengths = compute_slice_length(tcx, &ssa, body); debug!(?slice_lengths); @@ -41,7 +38,7 @@ fn compute_slice_length<'tcx>( ) -> IndexVec<Local, Option<ty::Const<'tcx>>> { let mut slice_lengths = IndexVec::from_elem(None, &body.local_decls); - for (local, rvalue) in ssa.assignments(body) { + for (local, rvalue, _) in ssa.assignments(body) { match rvalue { Rvalue::Cast( CastKind::Pointer(ty::adjustment::PointerCast::Unsize), diff --git a/compiler/rustc_mir_transform/src/nrvo.rs b/compiler/rustc_mir_transform/src/nrvo.rs index b6e73eaad50..85b26220b1e 100644 --- a/compiler/rustc_mir_transform/src/nrvo.rs +++ b/compiler/rustc_mir_transform/src/nrvo.rs @@ -34,7 +34,8 @@ pub struct RenameReturnPlace; impl<'tcx> MirPass<'tcx> for RenameReturnPlace { fn is_enabled(&self, sess: &rustc_session::Session) -> bool { - sess.mir_opt_level() > 0 + // #111005 + sess.mir_opt_level() > 0 && sess.opts.unstable_opts.unsound_mir_opts } fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut mir::Body<'tcx>) { diff --git a/compiler/rustc_mir_transform/src/ref_prop.rs b/compiler/rustc_mir_transform/src/ref_prop.rs new file mode 100644 index 00000000000..dafd2ae23a6 --- /dev/null +++ b/compiler/rustc_mir_transform/src/ref_prop.rs @@ -0,0 +1,355 @@ +use rustc_data_structures::fx::FxHashSet; +use rustc_index::bit_set::BitSet; +use rustc_index::IndexVec; +use rustc_middle::mir::visit::*; +use rustc_middle::mir::*; +use rustc_middle::ty::TyCtxt; +use rustc_mir_dataflow::impls::MaybeStorageDead; +use rustc_mir_dataflow::storage::always_storage_live_locals; +use rustc_mir_dataflow::Analysis; + +use crate::ssa::{SsaLocals, StorageLiveLocals}; +use crate::MirPass; + +/// Propagate references using SSA analysis. +/// +/// MIR building may produce a lot of borrow-dereference patterns. +/// +/// This pass aims to transform the following pattern: +/// _1 = &raw? mut? PLACE; +/// _3 = *_1; +/// _4 = &raw? mut? *_1; +/// +/// Into +/// _1 = &raw? mut? PLACE; +/// _3 = PLACE; +/// _4 = &raw? mut? PLACE; +/// +/// where `PLACE` is a direct or an indirect place expression. +/// +/// There are 3 properties that need to be upheld for this transformation to be legal: +/// - place stability: `PLACE` must refer to the same memory wherever it appears; +/// - pointer liveness: we must not introduce dereferences of dangling pointers; +/// - `&mut` borrow uniqueness. +/// +/// # Stability +/// +/// If `PLACE` is an indirect projection, if its of the form `(*LOCAL).PROJECTIONS` where: +/// - `LOCAL` is SSA; +/// - all projections in `PROJECTIONS` have a stable offset (no dereference and no indexing). +/// +/// If `PLACE` is a direct projection of a local, we consider it as constant if: +/// - the local is always live, or it has a single `StorageLive`; +/// - all projections have a stable offset. +/// +/// # Liveness +/// +/// When performing a substitution, we must take care not to introduce uses of dangling locals. +/// To ensure this, we walk the body with the `MaybeStorageDead` dataflow analysis: +/// - if we want to replace `*x` by reborrow `*y` and `y` may be dead, we allow replacement and +/// mark storage statements on `y` for removal; +/// - if we want to replace `*x` by non-reborrow `y` and `y` must be live, we allow replacement; +/// - if we want to replace `*x` by non-reborrow `y` and `y` may be dead, we do not replace. +/// +/// # Uniqueness +/// +/// For `&mut` borrows, we also need to preserve the uniqueness property: +/// we must avoid creating a state where we interleave uses of `*_1` and `_2`. +/// To do it, we only perform full substitution of mutable borrows: +/// we replace either all or none of the occurrences of `*_1`. +/// +/// Some care has to be taken when `_1` is copied in other locals. +/// _1 = &raw? mut? _2; +/// _3 = *_1; +/// _4 = _1 +/// _5 = *_4 +/// In such cases, fully substituting `_1` means fully substituting all of the copies. +/// +/// For immutable borrows, we do not need to preserve such uniqueness property, +/// so we perform all the possible substitutions without removing the `_1 = &_2` statement. +pub struct ReferencePropagation; + +impl<'tcx> MirPass<'tcx> for ReferencePropagation { + fn is_enabled(&self, sess: &rustc_session::Session) -> bool { + sess.mir_opt_level() >= 4 + } + + #[instrument(level = "trace", skip(self, tcx, body))] + fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { + debug!(def_id = ?body.source.def_id()); + propagate_ssa(tcx, body); + } +} + +fn propagate_ssa<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { + let ssa = SsaLocals::new(body); + + let mut replacer = compute_replacement(tcx, body, &ssa); + debug!(?replacer.targets, ?replacer.allowed_replacements, ?replacer.storage_to_remove); + + replacer.visit_body_preserves_cfg(body); + + if replacer.any_replacement { + crate::simplify::remove_unused_definitions(body); + } +} + +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +enum Value<'tcx> { + /// Not a pointer, or we can't know. + Unknown, + /// We know the value to be a pointer to this place. + /// The boolean indicates whether the reference is mutable, subject the uniqueness rule. + Pointer(Place<'tcx>, bool), +} + +/// For each local, save the place corresponding to `*local`. +#[instrument(level = "trace", skip(tcx, body))] +fn compute_replacement<'tcx>( + tcx: TyCtxt<'tcx>, + body: &Body<'tcx>, + ssa: &SsaLocals, +) -> Replacer<'tcx> { + let always_live_locals = always_storage_live_locals(body); + + // Compute which locals have a single `StorageLive` statement ever. + let storage_live = StorageLiveLocals::new(body, &always_live_locals); + + // Compute `MaybeStorageDead` dataflow to check that we only replace when the pointee is + // definitely live. + let mut maybe_dead = MaybeStorageDead::new(always_live_locals) + .into_engine(tcx, body) + .iterate_to_fixpoint() + .into_results_cursor(body); + + // Map for each local to the pointee. + let mut targets = IndexVec::from_elem(Value::Unknown, &body.local_decls); + // Set of locals for which we will remove their storage statement. This is useful for + // reborrowed references. + let mut storage_to_remove = BitSet::new_empty(body.local_decls.len()); + + let fully_replacable_locals = fully_replacable_locals(ssa); + + // Returns true iff we can use `place` as a pointee. + // + // Note that we only need to verify that there is a single `StorageLive` statement, and we do + // not need to verify that it dominates all uses of that local. + // + // Consider the three statements: + // SL : StorageLive(a) + // DEF: b = &raw? mut? a + // USE: stuff that uses *b + // + // First, we recall that DEF is checked to dominate USE. Now imagine for the sake of + // contradiction there is a DEF -> SL -> USE path. Consider two cases: + // + // - DEF dominates SL. We always have UB the first time control flow reaches DEF, + // because the storage of `a` is dead. Since DEF dominates USE, that means we cannot + // reach USE and so our optimization is ok. + // + // - DEF does not dominate SL. Then there is a `START_BLOCK -> SL` path not including DEF. + // But we can extend this path to USE, meaning there is also a `START_BLOCK -> USE` path not + // including DEF. This violates the DEF dominates USE condition, and so is impossible. + let is_constant_place = |place: Place<'_>| { + // We only allow `Deref` as the first projection, to avoid surprises. + if place.projection.first() == Some(&PlaceElem::Deref) { + // `place == (*some_local).xxx`, it is constant only if `some_local` is constant. + // We approximate constness using SSAness. + ssa.is_ssa(place.local) && place.projection[1..].iter().all(PlaceElem::is_stable_offset) + } else { + storage_live.has_single_storage(place.local) + && place.projection[..].iter().all(PlaceElem::is_stable_offset) + } + }; + + let mut can_perform_opt = |target: Place<'tcx>, loc: Location| { + if target.projection.first() == Some(&PlaceElem::Deref) { + // We are creating a reborrow. As `place.local` is a reference, removing the storage + // statements should not make it much harder for LLVM to optimize. + storage_to_remove.insert(target.local); + true + } else { + // This is a proper dereference. We can only allow it if `target` is live. + maybe_dead.seek_after_primary_effect(loc); + let maybe_dead = maybe_dead.contains(target.local); + !maybe_dead + } + }; + + for (local, rvalue, location) in ssa.assignments(body) { + debug!(?local); + + // Only visit if we have something to do. + let Value::Unknown = targets[local] else { bug!() }; + + let ty = body.local_decls[local].ty; + + // If this is not a reference or pointer, do nothing. + if !ty.is_any_ptr() { + debug!("not a reference or pointer"); + continue; + } + + // If this a mutable reference that we cannot fully replace, mark it as unknown. + if ty.is_mutable_ptr() && !fully_replacable_locals.contains(local) { + debug!("not fully replaceable"); + continue; + } + + debug!(?rvalue); + match rvalue { + // This is a copy, just use the value we have in store for the previous one. + // As we are visiting in `assignment_order`, ie. reverse postorder, `rhs` should + // have been visited before. + Rvalue::Use(Operand::Copy(place) | Operand::Move(place)) + | Rvalue::CopyForDeref(place) => { + if let Some(rhs) = place.as_local() { + let target = targets[rhs]; + if matches!(target, Value::Pointer(..)) { + targets[local] = target; + } else if ssa.is_ssa(rhs) { + let refmut = body.local_decls[rhs].ty.is_mutable_ptr(); + targets[local] = Value::Pointer(tcx.mk_place_deref(rhs.into()), refmut); + } + } + } + Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => { + let mut place = *place; + // Try to see through `place` in order to collapse reborrow chains. + if place.projection.first() == Some(&PlaceElem::Deref) + && let Value::Pointer(target, refmut) = targets[place.local] + // Only see through immutable reference and pointers, as we do not know yet if + // mutable references are fully replaced. + && !refmut + // Only collapse chain if the pointee is definitely live. + && can_perform_opt(target, location) + { + place = target.project_deeper(&place.projection[1..], tcx); + } + assert_ne!(place.local, local); + if is_constant_place(place) { + targets[local] = Value::Pointer(place, ty.is_mutable_ptr()); + } + } + // We do not know what to do, so keep as not-a-pointer. + _ => {} + } + } + + debug!(?targets); + + let mut finder = ReplacementFinder { + targets: &mut targets, + can_perform_opt, + allowed_replacements: FxHashSet::default(), + }; + let reachable_blocks = traversal::reachable_as_bitset(body); + for (bb, bbdata) in body.basic_blocks.iter_enumerated() { + // Only visit reachable blocks as we rely on dataflow. + if reachable_blocks.contains(bb) { + finder.visit_basic_block_data(bb, bbdata); + } + } + + let allowed_replacements = finder.allowed_replacements; + return Replacer { + tcx, + targets, + storage_to_remove, + allowed_replacements, + any_replacement: false, + }; + + struct ReplacementFinder<'a, 'tcx, F> { + targets: &'a mut IndexVec<Local, Value<'tcx>>, + can_perform_opt: F, + allowed_replacements: FxHashSet<(Local, Location)>, + } + + impl<'tcx, F> Visitor<'tcx> for ReplacementFinder<'_, 'tcx, F> + where + F: FnMut(Place<'tcx>, Location) -> bool, + { + fn visit_place(&mut self, place: &Place<'tcx>, ctxt: PlaceContext, loc: Location) { + if matches!(ctxt, PlaceContext::NonUse(_)) { + // There is no need to check liveness for non-uses. + return; + } + + if let Value::Pointer(target, refmut) = self.targets[place.local] + && place.projection.first() == Some(&PlaceElem::Deref) + { + let perform_opt = (self.can_perform_opt)(target, loc); + if perform_opt { + self.allowed_replacements.insert((target.local, loc)); + } else if refmut { + // This mutable reference is not fully replacable, so drop it. + self.targets[place.local] = Value::Unknown; + } + } + } + } +} + +/// Compute the set of locals that can be fully replaced. +/// +/// We consider a local to be replacable iff it's only used in a `Deref` projection `*_local` or +/// non-use position (like storage statements and debuginfo). +fn fully_replacable_locals(ssa: &SsaLocals) -> BitSet<Local> { + let mut replacable = BitSet::new_empty(ssa.num_locals()); + + // First pass: for each local, whether its uses can be fully replaced. + for local in ssa.locals() { + if ssa.num_direct_uses(local) == 0 { + replacable.insert(local); + } + } + + // Second pass: a local can only be fully replaced if all its copies can. + ssa.meet_copy_equivalence(&mut replacable); + + replacable +} + +/// Utility to help performing subtitution of `*pattern` by `target`. +struct Replacer<'tcx> { + tcx: TyCtxt<'tcx>, + targets: IndexVec<Local, Value<'tcx>>, + storage_to_remove: BitSet<Local>, + allowed_replacements: FxHashSet<(Local, Location)>, + any_replacement: bool, +} + +impl<'tcx> MutVisitor<'tcx> for Replacer<'tcx> { + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn visit_place(&mut self, place: &mut Place<'tcx>, ctxt: PlaceContext, loc: Location) { + if let Value::Pointer(target, _) = self.targets[place.local] + && place.projection.first() == Some(&PlaceElem::Deref) + { + let perform_opt = matches!(ctxt, PlaceContext::NonUse(_)) + || self.allowed_replacements.contains(&(target.local, loc)); + + if perform_opt { + *place = target.project_deeper(&place.projection[1..], self.tcx); + self.any_replacement = true; + } + } else { + self.super_place(place, ctxt, loc); + } + } + + fn visit_statement(&mut self, stmt: &mut Statement<'tcx>, loc: Location) { + match stmt.kind { + StatementKind::StorageLive(l) | StatementKind::StorageDead(l) + if self.storage_to_remove.contains(l) => + { + stmt.make_nop(); + } + // Do not remove assignments as they may still be useful for debuginfo. + _ => self.super_statement(stmt, loc), + } + } +} diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs index 7e0cef025f7..1b96df3aed5 100644 --- a/compiler/rustc_mir_transform/src/simplify.rs +++ b/compiler/rustc_mir_transform/src/simplify.rs @@ -278,7 +278,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> { } } -pub fn combine_duplicate_switch_targets(terminator: &mut Terminator<'_>) { +pub fn simplify_duplicate_switch_targets(terminator: &mut Terminator<'_>) { if let TerminatorKind::SwitchInt { targets, .. } = &mut terminator.kind { let otherwise = targets.otherwise(); if targets.iter().any(|t| t.1 == otherwise) { @@ -310,7 +310,7 @@ pub fn remove_duplicate_unreachable_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut B } } - combine_duplicate_switch_targets(terminator); + simplify_duplicate_switch_targets(terminator); self.super_terminator(terminator, location); } diff --git a/compiler/rustc_mir_transform/src/ssa.rs b/compiler/rustc_mir_transform/src/ssa.rs index ec8d42c1652..05a7b226f0c 100644 --- a/compiler/rustc_mir_transform/src/ssa.rs +++ b/compiler/rustc_mir_transform/src/ssa.rs @@ -1,3 +1,10 @@ +//! We denote as "SSA" the set of locals that verify the following properties: +//! 1/ They are only assigned-to once, either as a function parameter, or in an assign statement; +//! 2/ This single assignment dominates all uses; +//! +//! As a consequence of rule 2, we consider that borrowed locals are not SSA, even if they are +//! `Freeze`, as we do not track that the assignment dominates all uses of the borrow. + use either::Either; use rustc_data_structures::graph::dominators::Dominators; use rustc_index::bit_set::BitSet; @@ -5,7 +12,6 @@ use rustc_index::{IndexSlice, IndexVec}; use rustc_middle::middle::resolve_bound_vars::Set1; use rustc_middle::mir::visit::*; use rustc_middle::mir::*; -use rustc_middle::ty::{ParamEnv, TyCtxt}; #[derive(Debug)] pub struct SsaLocals { @@ -17,6 +23,9 @@ pub struct SsaLocals { assignment_order: Vec<Local>, /// Copy equivalence classes between locals. See `copy_classes` for documentation. copy_classes: IndexVec<Local, Local>, + /// Number of "direct" uses of each local, ie. uses that are not dereferences. + /// We ignore non-uses (Storage statements, debuginfo). + direct_uses: IndexVec<Local, u32>, } /// We often encounter MIR bodies with 1 or 2 basic blocks. In those cases, it's unnecessary to @@ -26,48 +35,48 @@ struct SmallDominators { inner: Option<Dominators<BasicBlock>>, } -trait DomExt { - fn dominates(self, _other: Self, dominators: &SmallDominators) -> bool; -} - -impl DomExt for Location { - fn dominates(self, other: Location, dominators: &SmallDominators) -> bool { - if self.block == other.block { - self.statement_index <= other.statement_index +impl SmallDominators { + fn dominates(&self, first: Location, second: Location) -> bool { + if first.block == second.block { + first.statement_index <= second.statement_index + } else if let Some(inner) = &self.inner { + inner.dominates(first.block, second.block) } else { - dominators.dominates(self.block, other.block) + first.block < second.block } } -} -impl SmallDominators { - fn dominates(&self, dom: BasicBlock, node: BasicBlock) -> bool { - if let Some(inner) = &self.inner { inner.dominates(dom, node) } else { dom < node } + fn check_dominates(&mut self, set: &mut Set1<LocationExtended>, loc: Location) { + let assign_dominates = match *set { + Set1::Empty | Set1::Many => false, + Set1::One(LocationExtended::Arg) => true, + Set1::One(LocationExtended::Plain(assign)) => { + self.dominates(assign.successor_within_block(), loc) + } + }; + // We are visiting a use that is not dominated by an assignment. + // Either there is a cycle involved, or we are reading for uninitialized local. + // Bail out. + if !assign_dominates { + *set = Set1::Many; + } } } impl SsaLocals { - pub fn new<'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ParamEnv<'tcx>, - body: &Body<'tcx>, - borrowed_locals: &BitSet<Local>, - ) -> SsaLocals { + pub fn new<'tcx>(body: &Body<'tcx>) -> SsaLocals { let assignment_order = Vec::with_capacity(body.local_decls.len()); let assignments = IndexVec::from_elem(Set1::Empty, &body.local_decls); let dominators = if body.basic_blocks.len() > 2 { Some(body.basic_blocks.dominators()) } else { None }; let dominators = SmallDominators { inner: dominators }; - let mut visitor = SsaVisitor { assignments, assignment_order, dominators }; - for (local, decl) in body.local_decls.iter_enumerated() { - if matches!(body.local_kind(local), LocalKind::Arg) { - visitor.assignments[local] = Set1::One(LocationExtended::Arg); - } - if borrowed_locals.contains(local) && !decl.ty.is_freeze(tcx, param_env) { - visitor.assignments[local] = Set1::Many; - } + let direct_uses = IndexVec::from_elem(0, &body.local_decls); + let mut visitor = SsaVisitor { assignments, assignment_order, dominators, direct_uses }; + + for local in body.args_iter() { + visitor.assignments[local] = Set1::One(LocationExtended::Arg); } if body.basic_blocks.len() > 2 { @@ -85,36 +94,51 @@ impl SsaLocals { } debug!(?visitor.assignments); + debug!(?visitor.direct_uses); visitor .assignment_order .retain(|&local| matches!(visitor.assignments[local], Set1::One(_))); debug!(?visitor.assignment_order); - let copy_classes = compute_copy_classes(&visitor, body); + let copy_classes = compute_copy_classes(&mut visitor, body); SsaLocals { assignments: visitor.assignments, assignment_order: visitor.assignment_order, + direct_uses: visitor.direct_uses, copy_classes, } } + pub fn num_locals(&self) -> usize { + self.assignments.len() + } + + pub fn locals(&self) -> impl Iterator<Item = Local> { + self.assignments.indices() + } + pub fn is_ssa(&self, local: Local) -> bool { matches!(self.assignments[local], Set1::One(_)) } + /// Return the number of uses if a local that are not "Deref". + pub fn num_direct_uses(&self, local: Local) -> u32 { + self.direct_uses[local] + } + pub fn assignments<'a, 'tcx>( &'a self, body: &'a Body<'tcx>, - ) -> impl Iterator<Item = (Local, &'a Rvalue<'tcx>)> + 'a { + ) -> impl Iterator<Item = (Local, &'a Rvalue<'tcx>, Location)> + 'a { self.assignment_order.iter().filter_map(|&local| { if let Set1::One(LocationExtended::Plain(loc)) = self.assignments[local] { // `loc` must point to a direct assignment to `local`. let Either::Left(stmt) = body.stmt_at(loc) else { bug!() }; let Some((target, rvalue)) = stmt.kind.as_assign() else { bug!() }; assert_eq!(target.as_local(), Some(local)); - Some((local, rvalue)) + Some((local, rvalue, loc)) } else { None } @@ -177,30 +201,14 @@ struct SsaVisitor { dominators: SmallDominators, assignments: IndexVec<Local, Set1<LocationExtended>>, assignment_order: Vec<Local>, -} - -impl SsaVisitor { - fn check_assignment_dominates(&mut self, local: Local, loc: Location) { - let set = &mut self.assignments[local]; - let assign_dominates = match *set { - Set1::Empty | Set1::Many => false, - Set1::One(LocationExtended::Arg) => true, - Set1::One(LocationExtended::Plain(assign)) => { - assign.successor_within_block().dominates(loc, &self.dominators) - } - }; - // We are visiting a use that is not dominated by an assignment. - // Either there is a cycle involved, or we are reading for uninitialized local. - // Bail out. - if !assign_dominates { - *set = Set1::Many; - } - } + direct_uses: IndexVec<Local, u32>, } impl<'tcx> Visitor<'tcx> for SsaVisitor { fn visit_local(&mut self, local: Local, ctxt: PlaceContext, loc: Location) { match ctxt { + PlaceContext::MutatingUse(MutatingUseContext::Projection) + | PlaceContext::NonMutatingUse(NonMutatingUseContext::Projection) => bug!(), PlaceContext::MutatingUse(MutatingUseContext::Store) => { self.assignments[local].insert(LocationExtended::Plain(loc)); if let Set1::One(_) = self.assignments[local] { @@ -209,12 +217,20 @@ impl<'tcx> Visitor<'tcx> for SsaVisitor { } } // Anything can happen with raw pointers, so remove them. - PlaceContext::NonMutatingUse(NonMutatingUseContext::AddressOf) - | PlaceContext::MutatingUse(_) => self.assignments[local] = Set1::Many, - // Immutable borrows are taken into account in `SsaLocals::new` by - // removing non-freeze locals. + // We do not verify that all uses of the borrow dominate the assignment to `local`, + // so we have to remove them too. + PlaceContext::NonMutatingUse( + NonMutatingUseContext::SharedBorrow + | NonMutatingUseContext::ShallowBorrow + | NonMutatingUseContext::UniqueBorrow + | NonMutatingUseContext::AddressOf, + ) + | PlaceContext::MutatingUse(_) => { + self.assignments[local] = Set1::Many; + } PlaceContext::NonMutatingUse(_) => { - self.check_assignment_dominates(local, loc); + self.dominators.check_dominates(&mut self.assignments[local], loc); + self.direct_uses[local] += 1; } PlaceContext::NonUse(_) => {} } @@ -224,20 +240,22 @@ impl<'tcx> Visitor<'tcx> for SsaVisitor { if place.projection.first() == Some(&PlaceElem::Deref) { // Do not do anything for storage statements and debuginfo. if ctxt.is_use() { - // A use through a `deref` only reads from the local, and cannot write to it. - let new_ctxt = PlaceContext::NonMutatingUse(NonMutatingUseContext::Projection); + // Only change the context if it is a real use, not a "use" in debuginfo. + let new_ctxt = PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy); self.visit_projection(place.as_ref(), new_ctxt, loc); - self.check_assignment_dominates(place.local, loc); + self.dominators.check_dominates(&mut self.assignments[place.local], loc); } return; + } else { + self.visit_projection(place.as_ref(), ctxt, loc); + self.visit_local(place.local, ctxt, loc); } - self.super_place(place, ctxt, loc); } } #[instrument(level = "trace", skip(ssa, body))] -fn compute_copy_classes(ssa: &SsaVisitor, body: &Body<'_>) -> IndexVec<Local, Local> { +fn compute_copy_classes(ssa: &mut SsaVisitor, body: &Body<'_>) -> IndexVec<Local, Local> { let mut copies = IndexVec::from_fn_n(|l| l, body.local_decls.len()); for &local in &ssa.assignment_order { @@ -267,9 +285,11 @@ fn compute_copy_classes(ssa: &SsaVisitor, body: &Body<'_>) -> IndexVec<Local, Lo // We visit in `assignment_order`, ie. reverse post-order, so `rhs` has been // visited before `local`, and we just have to copy the representing local. copies[local] = copies[rhs]; + ssa.direct_uses[rhs] -= 1; } debug!(?copies); + debug!(?ssa.direct_uses); // Invariant: `copies` must point to the head of an equivalence class. #[cfg(debug_assertions)] @@ -279,3 +299,36 @@ fn compute_copy_classes(ssa: &SsaVisitor, body: &Body<'_>) -> IndexVec<Local, Lo copies } + +#[derive(Debug)] +pub(crate) struct StorageLiveLocals { + /// Set of "StorageLive" statements for each local. + storage_live: IndexVec<Local, Set1<LocationExtended>>, +} + +impl StorageLiveLocals { + pub(crate) fn new( + body: &Body<'_>, + always_storage_live_locals: &BitSet<Local>, + ) -> StorageLiveLocals { + let mut storage_live = IndexVec::from_elem(Set1::Empty, &body.local_decls); + for local in always_storage_live_locals.iter() { + storage_live[local] = Set1::One(LocationExtended::Arg); + } + for (block, bbdata) in body.basic_blocks.iter_enumerated() { + for (statement_index, statement) in bbdata.statements.iter().enumerate() { + if let StatementKind::StorageLive(local) = statement.kind { + storage_live[local] + .insert(LocationExtended::Plain(Location { block, statement_index })); + } + } + } + debug!(?storage_live); + StorageLiveLocals { storage_live } + } + + #[inline] + pub(crate) fn has_single_storage(&self, local: Local) -> bool { + matches!(self.storage_live[local], Set1::One(_)) + } +} |