| // Copyright 2018 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| use rustc::mir::{Local, Location}; |
| use rustc::mir::Mir; |
| use rustc::mir::visit::PlaceContext; |
| use rustc::mir::visit::Visitor; |
| |
| crate trait FindAssignments { |
| // Finds all statements that assign directly to local (i.e., X = ...) |
| // and returns their locations. |
| fn find_assignments(&self, local: Local) -> Vec<Location>; |
| } |
| |
| impl<'tcx> FindAssignments for Mir<'tcx>{ |
| fn find_assignments(&self, local: Local) -> Vec<Location>{ |
| let mut visitor = FindLocalAssignmentVisitor{ needle: local, locations: vec![]}; |
| visitor.visit_mir(self); |
| visitor.locations |
| } |
| } |
| |
| // The Visitor walks the MIR to return the assignment statements corresponding |
| // to a Local. |
| struct FindLocalAssignmentVisitor { |
| needle: Local, |
| locations: Vec<Location>, |
| } |
| |
| impl<'tcx> Visitor<'tcx> for FindLocalAssignmentVisitor { |
| fn visit_local(&mut self, |
| local: &Local, |
| place_context: PlaceContext<'tcx>, |
| location: Location) { |
| if self.needle != *local { |
| return; |
| } |
| |
| if place_context.is_place_assignment() { |
| self.locations.push(location); |
| } |
| } |
| } |