Auto merge of #52046 - cramertj:fix-generator-mir, r=eddyb
Ensure StorageDead is created even if variable initialization fails Rebase and slight cleanup of https://github.com/rust-lang/rust/pull/51109 Fixes https://github.com/rust-lang/rust/issues/49232 r? @eddyb
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commit
e92e9ce0d8
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@ -102,7 +102,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
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});
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if let Some(scope) = scope {
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// schedule a shallow free of that memory, lest we unwind:
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this.schedule_drop(expr_span, scope, &Place::Local(result), value.ty);
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this.schedule_drop_storage_and_value(
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expr_span, scope, &Place::Local(result), value.ty,
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);
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}
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// malloc some memory of suitable type (thus far, uninitialized):
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@ -62,7 +62,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
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// anything because no values with a destructor can be created in
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// a constant at this time, even if the type may need dropping.
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if let Some(temp_lifetime) = temp_lifetime {
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this.schedule_drop(expr_span, temp_lifetime, &Place::Local(temp), expr_ty);
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this.schedule_drop_storage_and_value(
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expr_span, temp_lifetime, &Place::Local(temp), expr_ty,
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);
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}
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block.and(temp)
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@ -16,6 +16,7 @@
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use build::{BlockAnd, BlockAndExtension, Builder};
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use build::{GuardFrame, GuardFrameLocal, LocalsForNode};
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use build::ForGuard::{self, OutsideGuard, RefWithinGuard, ValWithinGuard};
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use build::scope::{CachedBlock, DropKind};
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use rustc_data_structures::fx::FxHashMap;
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use rustc_data_structures::bitvec::BitVector;
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use rustc::ty::{self, Ty};
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@ -367,7 +368,15 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
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source_info,
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kind: StatementKind::StorageLive(local_id)
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});
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Place::Local(local_id)
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let place = Place::Local(local_id);
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let var_ty = self.local_decls[local_id].ty;
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let hir_id = self.hir.tcx().hir.node_to_hir_id(var);
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let region_scope = self.hir.region_scope_tree.var_scope(hir_id.local_id);
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self.schedule_drop(
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span, region_scope, &place, var_ty,
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DropKind::Storage,
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);
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place
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}
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pub fn schedule_drop_for_binding(&mut self,
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@ -378,7 +387,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
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let var_ty = self.local_decls[local_id].ty;
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let hir_id = self.hir.tcx().hir.node_to_hir_id(var);
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let region_scope = self.hir.region_scope_tree.var_scope(hir_id.local_id);
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self.schedule_drop(span, region_scope, &Place::Local(local_id), var_ty);
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self.schedule_drop(
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span, region_scope, &Place::Local(local_id), var_ty,
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DropKind::Value {
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cached_block: CachedBlock::default(),
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},
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);
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}
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pub fn visit_bindings<F>(&mut self, pattern: &Pattern<'tcx>, f: &mut F)
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@ -10,6 +10,7 @@
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use build;
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use build::scope::{CachedBlock, DropKind};
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use hair::cx::Cx;
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use hair::{LintLevel, BindingMode, PatternKind};
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use rustc::hir;
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@ -744,9 +745,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
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}
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// Make sure we drop (parts of) the argument even when not matched on.
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self.schedule_drop(pattern.as_ref().map_or(ast_body.span, |pat| pat.span),
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argument_scope, &place, ty);
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self.schedule_drop(
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pattern.as_ref().map_or(ast_body.span, |pat| pat.span),
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argument_scope, &place, ty,
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DropKind::Value { cached_block: CachedBlock::default() },
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);
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}
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// Enter the argument pattern bindings source scope, if it exists.
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@ -144,12 +144,12 @@ struct DropData<'tcx> {
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/// place to drop
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location: Place<'tcx>,
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/// Whether this is a full value Drop, or just a StorageDead.
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kind: DropKind
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/// Whether this is a value Drop or a StorageDead.
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kind: DropKind,
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}
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#[derive(Debug, Default, Clone, Copy)]
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struct CachedBlock {
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pub(crate) struct CachedBlock {
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/// The cached block for the cleanups-on-diverge path. This block
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/// contains code to run the current drop and all the preceding
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/// drops (i.e. those having lower index in Drop’s Scope drop
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@ -166,7 +166,7 @@ struct CachedBlock {
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}
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#[derive(Debug)]
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enum DropKind {
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pub(crate) enum DropKind {
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Value {
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cached_block: CachedBlock,
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},
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@ -622,25 +622,58 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
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abortblk
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}
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pub fn schedule_drop_storage_and_value(
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&mut self,
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span: Span,
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region_scope: region::Scope,
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place: &Place<'tcx>,
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place_ty: Ty<'tcx>,
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) {
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self.schedule_drop(
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span, region_scope, place, place_ty,
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DropKind::Storage,
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);
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self.schedule_drop(
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span, region_scope, place, place_ty,
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DropKind::Value {
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cached_block: CachedBlock::default(),
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},
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);
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}
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// Scheduling drops
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// ================
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/// Indicates that `place` should be dropped on exit from
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/// `region_scope`.
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pub fn schedule_drop(&mut self,
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///
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/// When called with `DropKind::Storage`, `place` should be a local
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/// with an index higher than the current `self.arg_count`.
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pub fn schedule_drop(
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&mut self,
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span: Span,
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region_scope: region::Scope,
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place: &Place<'tcx>,
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place_ty: Ty<'tcx>) {
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place_ty: Ty<'tcx>,
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drop_kind: DropKind,
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) {
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let needs_drop = self.hir.needs_drop(place_ty);
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let drop_kind = if needs_drop {
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DropKind::Value { cached_block: CachedBlock::default() }
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} else {
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// Only temps and vars need their storage dead.
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match drop_kind {
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DropKind::Value { .. } => if !needs_drop { return },
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DropKind::Storage => {
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match *place {
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Place::Local(index) if index.index() > self.arg_count => DropKind::Storage,
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_ => return
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Place::Local(index) => if index.index() <= self.arg_count {
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span_bug!(
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span, "`schedule_drop` called with index {} and arg_count {}",
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index.index(),
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self.arg_count,
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)
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},
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_ => span_bug!(
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span, "`schedule_drop` called with non-`Local` place {:?}", place
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),
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}
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}
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}
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};
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for scope in self.scopes.iter_mut().rev() {
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let this_scope = scope.region_scope == region_scope;
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@ -895,9 +928,7 @@ fn build_scope_drops<'tcx>(cfg: &mut CFG<'tcx>,
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});
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block = next;
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}
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DropKind::Storage => {}
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}
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DropKind::Storage => {
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// We do not need to emit StorageDead for generator drops
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if generator_drop {
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continue
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@ -912,7 +943,9 @@ fn build_scope_drops<'tcx>(cfg: &mut CFG<'tcx>,
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kind: StatementKind::StorageDead(index)
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});
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}
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_ => continue
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_ => unreachable!(),
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}
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}
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}
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}
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block.unit()
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@ -31,11 +31,11 @@ pub fn test() {
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// CHECK: [[S__4:%[0-9]+]] = bitcast { i32, i32 }* %_4 to i8*
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// CHECK: call void @llvm.lifetime.start{{.*}}(i{{[0-9 ]+}}, i8* [[S__4]])
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// CHECK: [[E_b:%[0-9]+]] = bitcast { i32, i32 }** %b to i8*
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// CHECK: call void @llvm.lifetime.end{{.*}}(i{{[0-9 ]+}}, i8* [[E_b]])
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// CHECK: [[E__4:%[0-9]+]] = bitcast { i32, i32 }* %_4 to i8*
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// CHECK: call void @llvm.lifetime.end{{.*}}(i{{[0-9 ]+}}, i8* [[E__4]])
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// CHECK: [[E_b:%[0-9]+]] = bitcast { i32, i32 }** %b to i8*
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// CHECK: call void @llvm.lifetime.end{{.*}}(i{{[0-9 ]+}}, i8* [[E_b]])
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}
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let c = 1;
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@ -0,0 +1,148 @@
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// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// We must mark a variable whose initialization fails due to an
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// abort statement as StorageDead.
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fn main() {
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loop {
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let beacon = {
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match true {
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false => 4,
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true => break,
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}
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};
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drop(&beacon);
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}
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}
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// END RUST SOURCE
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// START rustc.main.mir_map.0.mir
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// fn main() -> (){
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// let mut _0: ();
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// scope 1 {
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// }
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// scope 2 {
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// let _2: i32;
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// }
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// let mut _1: ();
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// let mut _3: bool;
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// let mut _4: u8;
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// let mut _5: !;
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// let mut _6: ();
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// let mut _7: &i32;
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// bb0: {
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// goto -> bb1;
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// }
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// bb1: {
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// falseUnwind -> [real: bb3, cleanup: bb4];
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// }
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// bb2: {
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// goto -> bb29;
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// }
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// bb3: {
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// StorageLive(_2);
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// StorageLive(_3);
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// _3 = const true;
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// _4 = discriminant(_3);
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// switchInt(_3) -> [false: bb11, otherwise: bb10];
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// }
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// bb4: {
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// resume;
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// }
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// bb5: {
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// _2 = const 4i32;
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// goto -> bb14;
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// }
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// bb6: {
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// _0 = ();
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// goto -> bb15;
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// }
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// bb7: {
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// falseEdges -> [real: bb12, imaginary: bb8];
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// }
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// bb8: {
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// falseEdges -> [real: bb13, imaginary: bb9];
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// }
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// bb9: {
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// unreachable;
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// }
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// bb10: {
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// goto -> bb8;
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// }
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// bb11: {
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// goto -> bb7;
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// }
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// bb12: {
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// goto -> bb5;
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// }
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// bb13: {
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// goto -> bb6;
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// }
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// bb14: {
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// StorageDead(_3);
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// StorageLive(_7);
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// _7 = &_2;
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// _6 = const std::mem::drop(move _7) -> [return: bb28, unwind: bb4];
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// }
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// bb15: {
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// goto -> bb16;
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// }
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// bb16: {
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// goto -> bb17;
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// }
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// bb17: {
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// goto -> bb18;
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// }
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// bb18: {
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// goto -> bb19;
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// }
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// bb19: {
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// goto -> bb20;
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// }
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// bb20: {
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// StorageDead(_3);
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// goto -> bb21;
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// }
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// bb21: {
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// goto -> bb22;
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// }
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// bb22: {
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// StorageDead(_2);
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// goto -> bb23;
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// }
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// bb23: {
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// goto -> bb24;
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// }
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// bb24: {
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// goto -> bb25;
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// }
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// bb25: {
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// goto -> bb2;
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// }
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// bb26: {
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// _5 = ();
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// unreachable;
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// }
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// bb27: {
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// StorageDead(_5);
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// goto -> bb14;
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// }
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// bb28: {
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// StorageDead(_7);
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// _1 = ();
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// StorageDead(_2);
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// goto -> bb1;
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// }
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// bb29: {
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// return;
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// }
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// }
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// END rustc.main.mir_map.0.mir
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@ -31,8 +31,8 @@ fn main() {
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// StorageDead(_5);
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// _3 = &_4;
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// _2 = ();
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// StorageDead(_3);
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// StorageDead(_4);
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// StorageDead(_3);
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// StorageLive(_6);
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// _6 = const 1i32;
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// _0 = ();
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