use std::mem;
use rustc_index::IndexVec;
use rustc_middle::mir::tcx::{PlaceTy, RvalueInitializationState};
use rustc_middle::mir::*;
use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
use rustc_middle::{bug, span_bug};
use smallvec::{SmallVec, smallvec};
use tracing::debug;
use super::abs_domain::Lift;
use super::{
Init, InitIndex, InitKind, InitLocation, LocationMap, LookupResult, MoveData, MoveOut,
MoveOutIndex, MovePath, MovePathIndex, MovePathLookup,
};
struct MoveDataBuilder<'a, 'tcx, F> {
body: &'a Body<'tcx>,
loc: Location,
tcx: TyCtxt<'tcx>,
data: MoveData<'tcx>,
filter: F,
}
impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
fn new(body: &'a Body<'tcx>, tcx: TyCtxt<'tcx>, filter: F) -> Self {
let mut move_paths = IndexVec::new();
let mut path_map = IndexVec::new();
let mut init_path_map = IndexVec::new();
let locals = body
.local_decls
.iter_enumerated()
.map(|(i, l)| {
if l.is_deref_temp() {
return None;
}
if filter(l.ty) {
Some(new_move_path(
&mut move_paths,
&mut path_map,
&mut init_path_map,
None,
Place::from(i),
))
} else {
None
}
})
.collect();
MoveDataBuilder {
body,
loc: Location::START,
tcx,
data: MoveData {
moves: IndexVec::new(),
loc_map: LocationMap::new(body),
rev_lookup: MovePathLookup {
locals,
projections: Default::default(),
un_derefer: Default::default(),
},
move_paths,
path_map,
inits: IndexVec::new(),
init_loc_map: LocationMap::new(body),
init_path_map,
},
filter,
}
}
}
fn new_move_path<'tcx>(
move_paths: &mut IndexVec<MovePathIndex, MovePath<'tcx>>,
path_map: &mut IndexVec<MovePathIndex, SmallVec<[MoveOutIndex; 4]>>,
init_path_map: &mut IndexVec<MovePathIndex, SmallVec<[InitIndex; 4]>>,
parent: Option<MovePathIndex>,
place: Place<'tcx>,
) -> MovePathIndex {
let move_path =
move_paths.push(MovePath { next_sibling: None, first_child: None, parent, place });
if let Some(parent) = parent {
let next_sibling = mem::replace(&mut move_paths[parent].first_child, Some(move_path));
move_paths[move_path].next_sibling = next_sibling;
}
let path_map_ent = path_map.push(smallvec![]);
assert_eq!(path_map_ent, move_path);
let init_path_map_ent = init_path_map.push(smallvec![]);
assert_eq!(init_path_map_ent, move_path);
move_path
}
enum MovePathResult {
Path(MovePathIndex),
Union(MovePathIndex),
Error,
}
impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
fn move_path_for(&mut self, place: Place<'tcx>) -> MovePathResult {
let data = &mut self.data;
debug!("lookup({:?})", place);
let Some(mut base) = data.rev_lookup.find_local(place.local) else {
return MovePathResult::Error;
};
let mut union_path = None;
for (place_ref, elem) in data.rev_lookup.un_derefer.iter_projections(place.as_ref()) {
let body = self.body;
let tcx = self.tcx;
let place_ty = place_ref.ty(body, tcx).ty;
if place_ty.references_error() {
return MovePathResult::Error;
}
match elem {
ProjectionElem::Deref => match place_ty.kind() {
ty::Ref(..) | ty::RawPtr(..) => {
return MovePathResult::Error;
}
ty::Adt(adt, _) => {
if !adt.is_box() {
bug!("Adt should be a box type when Place is deref");
}
}
ty::Bool
| ty::Char
| ty::Int(_)
| ty::Uint(_)
| ty::Float(_)
| ty::Foreign(_)
| ty::Str
| ty::Array(_, _)
| ty::Pat(_, _)
| ty::Slice(_)
| ty::FnDef(_, _)
| ty::FnPtr(..)
| ty::Dynamic(_, _, _)
| ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::Coroutine(_, _)
| ty::CoroutineWitness(..)
| ty::Never
| ty::Tuple(_)
| ty::Alias(_, _)
| ty::Param(_)
| ty::Bound(_, _)
| ty::Infer(_)
| ty::Error(_)
| ty::Placeholder(_) => {
bug!("When Place is Deref it's type shouldn't be {place_ty:#?}")
}
},
ProjectionElem::Field(_, _) => match place_ty.kind() {
ty::Adt(adt, _) => {
if adt.has_dtor(tcx) {
return MovePathResult::Error;
}
if adt.is_union() {
union_path.get_or_insert(base);
}
}
ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::Coroutine(_, _)
| ty::Tuple(_) => (),
ty::Bool
| ty::Char
| ty::Int(_)
| ty::Uint(_)
| ty::Float(_)
| ty::Foreign(_)
| ty::Str
| ty::Array(_, _)
| ty::Pat(_, _)
| ty::Slice(_)
| ty::RawPtr(_, _)
| ty::Ref(_, _, _)
| ty::FnDef(_, _)
| ty::FnPtr(..)
| ty::Dynamic(_, _, _)
| ty::CoroutineWitness(..)
| ty::Never
| ty::Alias(_, _)
| ty::Param(_)
| ty::Bound(_, _)
| ty::Infer(_)
| ty::Error(_)
| ty::Placeholder(_) => bug!(
"When Place contains ProjectionElem::Field it's type shouldn't be {place_ty:#?}"
),
},
ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => {
match place_ty.kind() {
ty::Slice(_) => {
return MovePathResult::Error;
}
ty::Array(_, _) => (),
_ => bug!("Unexpected type {:#?}", place_ty.is_array()),
}
}
ProjectionElem::Index(_) => match place_ty.kind() {
ty::Array(..) | ty::Slice(_) => {
return MovePathResult::Error;
}
_ => bug!("Unexpected type {place_ty:#?}"),
},
ProjectionElem::OpaqueCast(_)
| ProjectionElem::Subtype(_)
| ProjectionElem::Downcast(_, _) => (),
}
let elem_ty = PlaceTy::from_ty(place_ty).projection_ty(tcx, elem).ty;
if !(self.filter)(elem_ty) {
return MovePathResult::Error;
}
if union_path.is_none() {
base =
*data.rev_lookup.projections.entry((base, elem.lift())).or_insert_with(|| {
new_move_path(
&mut data.move_paths,
&mut data.path_map,
&mut data.init_path_map,
Some(base),
place_ref.project_deeper(&[elem], tcx),
)
})
}
}
if let Some(base) = union_path {
MovePathResult::Union(base)
} else {
MovePathResult::Path(base)
}
}
fn add_move_path(
&mut self,
base: MovePathIndex,
elem: PlaceElem<'tcx>,
mk_place: impl FnOnce(TyCtxt<'tcx>) -> Place<'tcx>,
) -> MovePathIndex {
let MoveDataBuilder {
data: MoveData { rev_lookup, move_paths, path_map, init_path_map, .. },
tcx,
..
} = self;
*rev_lookup.projections.entry((base, elem.lift())).or_insert_with(move || {
new_move_path(move_paths, path_map, init_path_map, Some(base), mk_place(*tcx))
})
}
fn create_move_path(&mut self, place: Place<'tcx>) {
let _ = self.move_path_for(place);
}
fn finalize(self) -> MoveData<'tcx> {
debug!("{}", {
debug!("moves for {:?}:", self.body.span);
for (j, mo) in self.data.moves.iter_enumerated() {
debug!(" {:?} = {:?}", j, mo);
}
debug!("move paths for {:?}:", self.body.span);
for (j, path) in self.data.move_paths.iter_enumerated() {
debug!(" {:?} = {:?}", j, path);
}
"done dumping moves"
});
self.data
}
}
pub(super) fn gather_moves<'tcx>(
body: &Body<'tcx>,
tcx: TyCtxt<'tcx>,
filter: impl Fn(Ty<'tcx>) -> bool,
) -> MoveData<'tcx> {
let mut builder = MoveDataBuilder::new(body, tcx, filter);
builder.gather_args();
for (bb, block) in body.basic_blocks.iter_enumerated() {
for (i, stmt) in block.statements.iter().enumerate() {
builder.loc = Location { block: bb, statement_index: i };
builder.gather_statement(stmt);
}
builder.loc = Location { block: bb, statement_index: block.statements.len() };
builder.gather_terminator(block.terminator());
}
builder.finalize()
}
impl<'a, 'tcx, F: Fn(Ty<'tcx>) -> bool> MoveDataBuilder<'a, 'tcx, F> {
fn gather_args(&mut self) {
for arg in self.body.args_iter() {
if let Some(path) = self.data.rev_lookup.find_local(arg) {
let init = self.data.inits.push(Init {
path,
kind: InitKind::Deep,
location: InitLocation::Argument(arg),
});
debug!("gather_args: adding init {:?} of {:?} for argument {:?}", init, path, arg);
self.data.init_path_map[path].push(init);
}
}
}
fn gather_statement(&mut self, stmt: &Statement<'tcx>) {
debug!("gather_statement({:?}, {:?})", self.loc, stmt);
match &stmt.kind {
StatementKind::Assign(box (place, Rvalue::CopyForDeref(reffed))) => {
let local = place.as_local().unwrap();
assert!(self.body.local_decls[local].is_deref_temp());
let rev_lookup = &mut self.data.rev_lookup;
rev_lookup.un_derefer.insert(local, reffed.as_ref());
let base_local = rev_lookup.un_derefer.deref_chain(local).first().unwrap().local;
rev_lookup.locals[local] = rev_lookup.locals[base_local];
}
StatementKind::Assign(box (place, rval)) => {
self.create_move_path(*place);
if let RvalueInitializationState::Shallow = rval.initialization_state() {
self.create_move_path(self.tcx.mk_place_deref(*place));
self.gather_init(place.as_ref(), InitKind::Shallow);
} else {
self.gather_init(place.as_ref(), InitKind::Deep);
}
self.gather_rvalue(rval);
}
StatementKind::FakeRead(box (_, place)) => {
self.create_move_path(*place);
}
StatementKind::StorageLive(_) => {}
StatementKind::StorageDead(local) => {
if !self.body.local_decls[*local].is_deref_temp() {
self.gather_move(Place::from(*local));
}
}
StatementKind::SetDiscriminant { .. } | StatementKind::Deinit(..) => {
span_bug!(
stmt.source_info.span,
"SetDiscriminant/Deinit should not exist during borrowck"
);
}
StatementKind::Retag { .. }
| StatementKind::AscribeUserType(..)
| StatementKind::PlaceMention(..)
| StatementKind::Coverage(..)
| StatementKind::Intrinsic(..)
| StatementKind::ConstEvalCounter
| StatementKind::BackwardIncompatibleDropHint { .. }
| StatementKind::Nop => {}
}
}
fn gather_rvalue(&mut self, rvalue: &Rvalue<'tcx>) {
match *rvalue {
Rvalue::ThreadLocalRef(_) => {} Rvalue::Use(ref operand)
| Rvalue::Repeat(ref operand, _)
| Rvalue::Cast(_, ref operand, _)
| Rvalue::ShallowInitBox(ref operand, _)
| Rvalue::UnaryOp(_, ref operand) => self.gather_operand(operand),
Rvalue::BinaryOp(ref _binop, box (ref lhs, ref rhs)) => {
self.gather_operand(lhs);
self.gather_operand(rhs);
}
Rvalue::Aggregate(ref _kind, ref operands) => {
for operand in operands {
self.gather_operand(operand);
}
}
Rvalue::CopyForDeref(..) => unreachable!(),
Rvalue::Ref(..)
| Rvalue::RawPtr(..)
| Rvalue::Discriminant(..)
| Rvalue::Len(..)
| Rvalue::NullaryOp(
NullOp::SizeOf | NullOp::AlignOf | NullOp::OffsetOf(..) | NullOp::UbChecks,
_,
) => {}
}
}
fn gather_terminator(&mut self, term: &Terminator<'tcx>) {
debug!("gather_terminator({:?}, {:?})", self.loc, term);
match term.kind {
TerminatorKind::Goto { target: _ }
| TerminatorKind::FalseEdge { .. }
| TerminatorKind::FalseUnwind { .. }
| TerminatorKind::Return
| TerminatorKind::UnwindResume
| TerminatorKind::UnwindTerminate(_)
| TerminatorKind::CoroutineDrop
| TerminatorKind::Unreachable
| TerminatorKind::Drop { .. } => {}
TerminatorKind::Assert { ref cond, .. } => {
self.gather_operand(cond);
}
TerminatorKind::SwitchInt { ref discr, .. } => {
self.gather_operand(discr);
}
TerminatorKind::Yield { ref value, resume_arg: place, .. } => {
self.gather_operand(value);
self.create_move_path(place);
self.gather_init(place.as_ref(), InitKind::Deep);
}
TerminatorKind::Call {
ref func,
ref args,
destination,
target,
unwind: _,
call_source: _,
fn_span: _,
} => {
self.gather_operand(func);
for arg in args {
self.gather_operand(&arg.node);
}
if let Some(_bb) = target {
self.create_move_path(destination);
self.gather_init(destination.as_ref(), InitKind::NonPanicPathOnly);
}
}
TerminatorKind::TailCall { ref func, ref args, .. } => {
self.gather_operand(func);
for arg in args {
self.gather_operand(&arg.node);
}
}
TerminatorKind::InlineAsm {
asm_macro: _,
template: _,
ref operands,
options: _,
line_spans: _,
targets: _,
unwind: _,
} => {
for op in operands {
match *op {
InlineAsmOperand::In { reg: _, ref value }
=> {
self.gather_operand(value);
}
InlineAsmOperand::Out { reg: _, late: _, place, .. } => {
if let Some(place) = place {
self.create_move_path(place);
self.gather_init(place.as_ref(), InitKind::Deep);
}
}
InlineAsmOperand::InOut { reg: _, late: _, ref in_value, out_place } => {
self.gather_operand(in_value);
if let Some(out_place) = out_place {
self.create_move_path(out_place);
self.gather_init(out_place.as_ref(), InitKind::Deep);
}
}
InlineAsmOperand::Const { value: _ }
| InlineAsmOperand::SymFn { value: _ }
| InlineAsmOperand::SymStatic { def_id: _ }
| InlineAsmOperand::Label { target_index: _ } => {}
}
}
}
}
}
fn gather_operand(&mut self, operand: &Operand<'tcx>) {
match *operand {
Operand::Constant(..) | Operand::Copy(..) => {} Operand::Move(place) => {
self.gather_move(place);
}
}
}
fn gather_move(&mut self, place: Place<'tcx>) {
debug!("gather_move({:?}, {:?})", self.loc, place);
if let [ref base @ .., ProjectionElem::Subslice { from, to, from_end: false }] =
**place.projection
{
let base_place =
Place { local: place.local, projection: self.tcx.mk_place_elems(base) };
let base_path = match self.move_path_for(base_place) {
MovePathResult::Path(path) => path,
MovePathResult::Union(path) => {
self.record_move(place, path);
return;
}
MovePathResult::Error => {
return;
}
};
let base_ty = base_place.ty(self.body, self.tcx).ty;
let len: u64 = match base_ty.kind() {
ty::Array(_, size) => size
.try_to_target_usize(self.tcx)
.expect("expected subslice projection on fixed-size array"),
_ => bug!("from_end: false slice pattern of non-array type"),
};
for offset in from..to {
let elem =
ProjectionElem::ConstantIndex { offset, min_length: len, from_end: false };
let path =
self.add_move_path(base_path, elem, |tcx| tcx.mk_place_elem(base_place, elem));
self.record_move(place, path);
}
} else {
match self.move_path_for(place) {
MovePathResult::Path(path) | MovePathResult::Union(path) => {
self.record_move(place, path)
}
MovePathResult::Error => {}
};
}
}
fn record_move(&mut self, place: Place<'tcx>, path: MovePathIndex) {
let move_out = self.data.moves.push(MoveOut { path, source: self.loc });
debug!(
"gather_move({:?}, {:?}): adding move {:?} of {:?}",
self.loc, place, move_out, path
);
self.data.path_map[path].push(move_out);
self.data.loc_map[self.loc].push(move_out);
}
fn gather_init(&mut self, place: PlaceRef<'tcx>, kind: InitKind) {
debug!("gather_init({:?}, {:?})", self.loc, place);
let mut place = place;
if let Some((place_base, ProjectionElem::Field(_, _))) = place.last_projection() {
if place_base.ty(self.body, self.tcx).ty.is_union() {
place = place_base;
}
}
if let LookupResult::Exact(path) = self.data.rev_lookup.find(place) {
let init = self.data.inits.push(Init {
location: InitLocation::Statement(self.loc),
path,
kind,
});
debug!(
"gather_init({:?}, {:?}): adding init {:?} of {:?}",
self.loc, place, init, path
);
self.data.init_path_map[path].push(init);
self.data.init_loc_map[self.loc].push(init);
}
}
}