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[beta] const eval perf regression fix #53825

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merged 3 commits into from
Aug 31, 2018
Merged

[beta] const eval perf regression fix #53825

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b6cb9b6
check_const: use the same ParamEnv as codegen for statics
RalfJung Jul 31, 2018
4a89558
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RalfJung Aug 1, 2018
860b257
Don't hash the ctfe memory
oli-obk Aug 30, 2018
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12 changes: 9 additions & 3 deletions src/librustc_lint/builtin.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1631,16 +1631,22 @@ fn validate_const<'a, 'tcx>(

fn check_const(cx: &LateContext, body_id: hir::BodyId, what: &str) {
let def_id = cx.tcx.hir.body_owner_def_id(body_id);
let param_env = cx.tcx.param_env(def_id);
let is_static = cx.tcx.is_static(def_id).is_some();
let param_env = if is_static {
// Use the same param_env as `codegen_static_initializer`, to reuse the cache.
ty::ParamEnv::reveal_all()
} else {
cx.tcx.param_env(def_id)
};
let cid = ::rustc::mir::interpret::GlobalId {
instance: ty::Instance::mono(cx.tcx, def_id),
promoted: None
};
match cx.tcx.const_eval(param_env.and(cid)) {
Ok(val) => validate_const(cx.tcx, val, param_env, cid, what),
Err(err) => {
// errors for statics are already reported directly in the query
if cx.tcx.is_static(def_id).is_none() {
// errors for statics are already reported directly in the query, avoid duplicates
if !is_static {
let span = cx.tcx.def_span(def_id);
err.report_as_lint(
cx.tcx.at(span),
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6 changes: 3 additions & 3 deletions src/librustc_mir/interpret/eval_context.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -214,10 +214,10 @@ impl<'a, 'mir, 'tcx, M> InfiniteLoopDetector<'a, 'mir, 'tcx, M>
stack: &Vec<Frame<'mir, 'tcx>>,
memory: &Memory<'a, 'mir, 'tcx, M>,
) -> EvalResult<'tcx, ()> {
let snapshot = (machine, stack, memory);

let mut fx = FxHasher::default();
snapshot.hash(&mut fx);
// don't hash the memory, that takes too much time, just compare when you hit a collision
// should be rare enough
(machine, stack).hash(&mut fx);
let hash = fx.finish();

if self.hashes.insert(hash) {
Expand Down