// Arguments get assigned to by means of the function being called
for arg in mir.args_iter() {
- analyzer.assign(arg, mir::START_BLOCK.start_location());
+ analyzer.assign(arg, DefLocation::Argument);
}
// If there exists a local definition that dominates all uses of that local,
/// A scalar or a scalar pair local that is neither defined nor used.
Unused,
/// A scalar or a scalar pair local with a single definition that dominates all uses.
- SSA(mir::Location),
+ SSA(DefLocation),
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+enum DefLocation {
+ Argument,
+ Body(Location),
+}
+
+impl DefLocation {
+ fn dominates(self, location: Location, dominators: &Dominators<mir::BasicBlock>) -> bool {
+ match self {
+ DefLocation::Argument => true,
+ DefLocation::Body(def) => def.successor_within_block().dominates(location, dominators),
+ }
+ }
}
struct LocalAnalyzer<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
}
impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> LocalAnalyzer<'mir, 'a, 'tcx, Bx> {
- fn assign(&mut self, local: mir::Local, location: Location) {
+ fn assign(&mut self, local: mir::Local, location: DefLocation) {
let kind = &mut self.locals[local];
match *kind {
LocalKind::ZST => {}
LocalKind::Memory => {}
- LocalKind::Unused => {
- *kind = LocalKind::SSA(location);
- }
- LocalKind::SSA(_) => {
- *kind = LocalKind::Memory;
- }
+ LocalKind::Unused => *kind = LocalKind::SSA(location),
+ LocalKind::SSA(_) => *kind = LocalKind::Memory,
}
}
debug!("visit_assign(place={:?}, rvalue={:?})", place, rvalue);
if let Some(local) = place.as_local() {
- self.assign(local, location);
+ self.assign(local, DefLocation::Body(location));
if self.locals[local] != LocalKind::Memory {
let decl_span = self.fx.mir.local_decls[local].source_info.span;
if !self.fx.rvalue_creates_operand(rvalue, decl_span) {
match context {
PlaceContext::MutatingUse(MutatingUseContext::Call)
| PlaceContext::MutatingUse(MutatingUseContext::Yield) => {
- self.assign(local, location);
+ self.assign(local, DefLocation::Body(location));
}
PlaceContext::NonUse(_) | PlaceContext::MutatingUse(MutatingUseContext::Retag) => {}