65 lines
2.4 KiB
Rust
65 lines
2.4 KiB
Rust
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// Copyright 2017 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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use rustc::mir::Mir;
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use rustc::infer::InferCtxt;
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use util::liveness::LivenessResult;
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use super::ToRegionIndex;
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use super::region_infer::RegionInferenceContext;
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pub fn generate_constraints<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
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regioncx: &mut RegionInferenceContext,
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mir: &Mir<'tcx>,
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liveness: &LivenessResult)
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{
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ConstraintGeneration { infcx, regioncx, mir, liveness }.add_constraints();
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}
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struct ConstraintGeneration<'constrain, 'gcx: 'tcx, 'tcx: 'constrain> {
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infcx: &'constrain InferCtxt<'constrain, 'gcx, 'tcx>,
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regioncx: &'constrain mut RegionInferenceContext,
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mir: &'constrain Mir<'tcx>,
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liveness: &'constrain LivenessResult,
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}
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impl<'constrain, 'gcx, 'tcx> ConstraintGeneration<'constrain, 'gcx, 'tcx> {
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fn add_constraints(&mut self) {
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// To start, add the liveness constraints.
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self.add_liveness_constraints();
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}
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/// Liveness constraints:
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///
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/// > If a variable V is live at point P, then all regions R in the type of V
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/// > must include the point P.
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fn add_liveness_constraints(&mut self) {
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let tcx = self.infcx.tcx;
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debug!("add_liveness_constraints()");
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for bb in self.mir.basic_blocks().indices() {
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debug!("add_liveness_constraints: bb={:?}", bb);
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self.liveness.simulate_block(self.mir, bb, |location, live_locals| {
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debug!("add_liveness_constraints: location={:?} live_locals={:?}",
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location, live_locals);
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for live_local in live_locals.iter() {
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let live_local_ty = self.mir.local_decls[live_local].ty;
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tcx.for_each_free_region(&live_local_ty, |live_region| {
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let vid = live_region.to_region_index();
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self.regioncx.add_live_point(vid, location);
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})
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}
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});
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}
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}
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}
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