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Use new PromoteTemps for promotion

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This commit is contained in:
Dylan MacKenzie 2019-11-06 14:23:35 -08:00
parent 170272b74f
commit b316384e14
3 changed files with 27 additions and 48 deletions
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7
src/librustc_mir/transform/mod.rs
View file

@ -210,13 +210,14 @@ fn mir_validated(
}
let mut body = tcx.mir_const(def_id).steal();
let qualify_and_promote_pass = qualify_consts::QualifyAndPromoteConstants::default();
let promote_pass = promote_consts::PromoteTemps::default();
run_passes(tcx, &mut body, InstanceDef::Item(def_id), None, MirPhase::Validated, &[
// What we need to run borrowck etc.
&qualify_and_promote_pass,
&qualify_consts::QualifyAndPromoteConstants::default(),
&promote_pass,
&simplify::SimplifyCfg::new("qualify-consts"),
]);
let promoted = qualify_and_promote_pass.promoted.into_inner();
let promoted = promote_pass.promoted_fragments.into_inner();
(tcx.alloc_steal_mir(body), tcx.alloc_steal_promoted(promoted))
}

56
src/librustc_mir/transform/qualify_consts.rs
View file

@ -1345,48 +1345,27 @@ impl<'tcx> MirPass<'tcx> for QualifyAndPromoteConstants<'tcx> {
let mode = determine_mode(tcx, hir_id, def_id);
debug!("run_pass: mode={:?}", mode);
if let Mode::NonConstFn | Mode::ConstFn = mode {
if let Mode::NonConstFn = mode {
// No need to const-check a non-const `fn` now that we don't do promotion here.
return;
} else if let Mode::ConstFn = mode {
let mut checker = Checker::new(tcx, def_id, body, mode);
if let Mode::ConstFn = mode {
let use_min_const_fn_checks =
!tcx.sess.opts.debugging_opts.unleash_the_miri_inside_of_you &&
tcx.is_min_const_fn(def_id);
if use_min_const_fn_checks {
// Enforce `min_const_fn` for stable `const fn`s.
use super::qualify_min_const_fn::is_min_const_fn;
if let Err((span, err)) = is_min_const_fn(tcx, def_id, body) {
error_min_const_fn_violation(tcx, span, err);
return;
}
// `check_const` should not produce any errors, but better safe than sorry
// FIXME(#53819)
// NOTE(eddyb) `check_const` is actually needed for promotion inside
// `min_const_fn` functions.
}
// Enforce a constant-like CFG for `const fn`.
checker.check_const();
} else {
while let Some((bb, data)) = checker.rpo.next() {
checker.visit_basic_block_data(bb, data);
let use_min_const_fn_checks =
!tcx.sess.opts.debugging_opts.unleash_the_miri_inside_of_you &&
tcx.is_min_const_fn(def_id);
if use_min_const_fn_checks {
// Enforce `min_const_fn` for stable `const fn`s.
use super::qualify_min_const_fn::is_min_const_fn;
if let Err((span, err)) = is_min_const_fn(tcx, def_id, body) {
error_min_const_fn_violation(tcx, span, err);
return;
}
}
// Promote only the promotable candidates.
let temps = checker.temp_promotion_state;
let candidates = promote_consts::validate_candidates(
tcx,
body,
def_id,
&temps,
&checker.unchecked_promotion_candidates,
);
// Do the actual promotion, now that we know what's viable.
self.promoted.set(
promote_consts::promote_candidates(def_id, body, tcx, temps, candidates)
);
// `check_const` should not produce any errors, but better safe than sorry
// FIXME(#53819)
// Enforce a constant-like CFG for `const fn`.
checker.check_const();
} else {
check_short_circuiting_in_const_local(tcx, body, mode);
@ -1394,7 +1373,6 @@ impl<'tcx> MirPass<'tcx> for QualifyAndPromoteConstants<'tcx> {
Mode::Const => tcx.mir_const_qualif(def_id),
_ => Checker::new(tcx, def_id, body, mode).check_const(),
};
remove_drop_and_storage_dead_on_promoted_locals(body, unimplemented!());
}
if mode == Mode::Static && !tcx.has_attr(def_id, sym::thread_local) {

12
src/test/mir-opt/match_false_edges.rs
View file

@ -39,7 +39,7 @@ fn main() {
// END RUST SOURCE
//
// START rustc.full_tested_match.QualifyAndPromoteConstants.after.mir
// START rustc.full_tested_match.PromoteTemps.after.mir
// bb0: {
// ...
// _2 = std::option::Option::<i32>::Some(const 42i32,);
@ -108,9 +108,9 @@ fn main() {
// _0 = ();
// return;
// }
// END rustc.full_tested_match.QualifyAndPromoteConstants.after.mir
// END rustc.full_tested_match.PromoteTemps.after.mir
//
// START rustc.full_tested_match2.QualifyAndPromoteConstants.before.mir
// START rustc.full_tested_match2.PromoteTemps.before.mir
// bb0: {
// ...
// _2 = std::option::Option::<i32>::Some(const 42i32,);
@ -179,9 +179,9 @@ fn main() {
// _0 = ();
// return;
// }
// END rustc.full_tested_match2.QualifyAndPromoteConstants.before.mir
// END rustc.full_tested_match2.PromoteTemps.before.mir
//
// START rustc.main.QualifyAndPromoteConstants.before.mir
// START rustc.main.PromoteTemps.before.mir
// bb0: {
// ...
// _2 = std::option::Option::<i32>::Some(const 1i32,);
@ -276,4 +276,4 @@ fn main() {
// _0 = ();
// return;
// }
// END rustc.main.QualifyAndPromoteConstants.before.mir
// END rustc.main.PromoteTemps.before.mir