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Hold index of generator self arg in const
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@ecstatic-morse
ecstatic-morse committed Mar 14, 2020
1 parent 1f7b537 commit 08d345e
Showing 1 changed file with 18 additions and 21 deletions.
39 changes: 18 additions & 21 deletions src/librustc_mir/transform/generator.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -107,15 +107,15 @@ impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor<'tcx> {
}

fn visit_local(&mut self, local: &mut Local, _: PlaceContext, _: Location) {
assert_ne!(*local, self_arg());
assert_ne!(*local, SELF_ARG);
}

fn visit_place(&mut self, place: &mut Place<'tcx>, context: PlaceContext, location: Location) {
if place.local == self_arg() {
if place.local == SELF_ARG {
replace_base(
place,
Place {
local: self_arg(),
local: SELF_ARG,
projection: self.tcx().intern_place_elems(&[ProjectionElem::Deref]),
},
self.tcx,
Expand All @@ -125,7 +125,7 @@ impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor<'tcx> {

for elem in place.projection.iter() {
if let PlaceElem::Index(local) = elem {
assert_ne!(*local, self_arg());
assert_ne!(*local, SELF_ARG);
}
}
}
Expand All @@ -143,15 +143,15 @@ impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
}

fn visit_local(&mut self, local: &mut Local, _: PlaceContext, _: Location) {
assert_ne!(*local, self_arg());
assert_ne!(*local, SELF_ARG);
}

fn visit_place(&mut self, place: &mut Place<'tcx>, context: PlaceContext, location: Location) {
if place.local == self_arg() {
if place.local == SELF_ARG {
replace_base(
place,
Place {
local: self_arg(),
local: SELF_ARG,
projection: self.tcx().intern_place_elems(&[ProjectionElem::Field(
Field::new(0),
self.ref_gen_ty,
Expand All @@ -164,7 +164,7 @@ impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {

for elem in place.projection.iter() {
if let PlaceElem::Index(local) = elem {
assert_ne!(*local, self_arg());
assert_ne!(*local, SELF_ARG);
}
}
}
Expand All @@ -180,9 +180,7 @@ fn replace_base<'tcx>(place: &mut Place<'tcx>, new_base: Place<'tcx>, tcx: TyCtx
place.projection = tcx.intern_place_elems(&new_projection);
}

fn self_arg() -> Local {
Local::new(1)
}
const SELF_ARG: Local = Local::from_u32(1);

/// Generator has not been resumed yet.
const UNRESUMED: usize = GeneratorSubsts::UNRESUMED;
Expand Down Expand Up @@ -237,7 +235,7 @@ impl TransformVisitor<'tcx> {

// Create a Place referencing a generator struct field
fn make_field(&self, variant_index: VariantIdx, idx: usize, ty: Ty<'tcx>) -> Place<'tcx> {
let self_place = Place::from(self_arg());
let self_place = Place::from(SELF_ARG);
let base = self.tcx.mk_place_downcast_unnamed(self_place, variant_index);
let mut projection = base.projection.to_vec();
projection.push(ProjectionElem::Field(Field::new(idx), ty));
Expand All @@ -247,7 +245,7 @@ impl TransformVisitor<'tcx> {

// Create a statement which changes the discriminant
fn set_discr(&self, state_disc: VariantIdx, source_info: SourceInfo) -> Statement<'tcx> {
let self_place = Place::from(self_arg());
let self_place = Place::from(SELF_ARG);
Statement {
source_info,
kind: StatementKind::SetDiscriminant {
Expand All @@ -263,7 +261,7 @@ impl TransformVisitor<'tcx> {
let local_decls_len = body.local_decls.push(temp_decl);
let temp = Place::from(local_decls_len);

let self_place = Place::from(self_arg());
let self_place = Place::from(SELF_ARG);
let assign = Statement {
source_info: source_info(body),
kind: StatementKind::Assign(box (temp, Rvalue::Discriminant(self_place))),
Expand Down Expand Up @@ -540,7 +538,7 @@ fn locals_live_across_suspend_points(
live_locals_here.intersect(&liveness.outs[block]);

// The generator argument is ignored.
live_locals_here.remove(self_arg());
live_locals_here.remove(SELF_ARG);

debug!("loc = {:?}, live_locals_here = {:?}", loc, live_locals_here);

Expand Down Expand Up @@ -837,15 +835,14 @@ fn elaborate_generator_drops<'tcx>(
// generator's resume function.

let param_env = tcx.param_env(def_id);
let gen = self_arg();

let mut elaborator = DropShimElaborator { body, patch: MirPatch::new(body), tcx, param_env };

for (block, block_data) in body.basic_blocks().iter_enumerated() {
let (target, unwind, source_info) = match block_data.terminator() {
Terminator { source_info, kind: TerminatorKind::Drop { location, target, unwind } } => {
if let Some(local) = location.as_local() {
if local == gen {
if local == SELF_ARG {
(target, unwind, source_info)
} else {
continue;
Expand All @@ -864,7 +861,7 @@ fn elaborate_generator_drops<'tcx>(
elaborate_drop(
&mut elaborator,
*source_info,
&Place::from(gen),
&Place::from(SELF_ARG),
(),
*target,
unwind,
Expand Down Expand Up @@ -918,7 +915,7 @@ fn create_generator_drop_shim<'tcx>(
make_generator_state_argument_indirect(tcx, def_id, &mut body);

// Change the generator argument from &mut to *mut
body.local_decls[self_arg()] = LocalDecl {
body.local_decls[SELF_ARG] = LocalDecl {
mutability: Mutability::Mut,
ty: tcx.mk_ptr(ty::TypeAndMut { ty: gen_ty, mutbl: hir::Mutability::Mut }),
user_ty: UserTypeProjections::none(),
Expand All @@ -933,7 +930,7 @@ fn create_generator_drop_shim<'tcx>(
0,
Statement {
source_info,
kind: StatementKind::Retag(RetagKind::Raw, box Place::from(self_arg())),
kind: StatementKind::Retag(RetagKind::Raw, box Place::from(SELF_ARG)),
},
)
}
Expand Down Expand Up @@ -1042,7 +1039,7 @@ fn insert_clean_drop(body: &mut BodyAndCache<'_>) -> BasicBlock {
// Create a block to destroy an unresumed generators. This can only destroy upvars.
let drop_clean = BasicBlock::new(body.basic_blocks().len());
let term = TerminatorKind::Drop {
location: Place::from(self_arg()),
location: Place::from(SELF_ARG),
target: return_block,
unwind: None,
};
Expand Down

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