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rustc: use monomorphic const_eval for cross-crate enum discriminants.

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This commit is contained in:
Eduard-Mihai Burtescu 2017-04-15 04:14:44 +03:00
parent 63064ec190
commit 6dc21b71cf
14 changed files with 139 additions and 149 deletions
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47
src/librustc/ty/mod.rs
View file

@ -1660,7 +1660,7 @@ impl<'a, 'gcx, 'tcx> AdtDef {
self.variants.iter().map(move |v| {
let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
if let VariantDiscr::Explicit(expr_did) = v.discr {
match tcx.maps.monomorphic_const_eval.borrow()[&expr_did] {
match queries::monomorphic_const_eval::get(tcx, DUMMY_SP, expr_did) {
Ok(ConstVal::Integral(v)) => {
discr = v;
}
@ -1673,6 +1673,51 @@ impl<'a, 'gcx, 'tcx> AdtDef {
})
}
/// Compute the discriminant value used by a specific variant.
/// Unlike `discriminants`, this is (amortized) constant-time,
/// only doing at most one query for evaluating an explicit
/// discriminant (the last one before the requested variant),
/// assuming there are no constant-evaluation errors there.
pub fn discriminant_for_variant(&self,
tcx: TyCtxt<'a, 'gcx, 'tcx>,
variant_index: usize)
-> ConstInt {
let repr_type = self.repr.discr_type();
let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
let mut explicit_index = variant_index;
loop {
match self.variants[explicit_index].discr {
ty::VariantDiscr::Relative(0) => break,
ty::VariantDiscr::Relative(distance) => {
explicit_index -= distance;
}
ty::VariantDiscr::Explicit(expr_did) => {
match queries::monomorphic_const_eval::get(tcx, DUMMY_SP, expr_did) {
Ok(ConstVal::Integral(v)) => {
explicit_value = v;
break;
}
_ => {
explicit_index -= 1;
}
}
}
}
}
let discr = explicit_value.to_u128_unchecked()
.wrapping_add((variant_index - explicit_index) as u128);
match repr_type {
attr::UnsignedInt(ty) => {
ConstInt::new_unsigned_truncating(discr, ty,
tcx.sess.target.uint_type)
}
attr::SignedInt(ty) => {
ConstInt::new_signed_truncating(discr as i128, ty,
tcx.sess.target.int_type)
}
}
}
pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
queries::adt_destructor::get(tcx, DUMMY_SP, self.did)
}

11
src/librustc_const_eval/eval.rs
View file

@ -804,10 +804,13 @@ pub fn provide(providers: &mut Providers) {
fn monomorphic_const_eval<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
def_id: DefId)
-> EvalResult<'tcx> {
ty::queries::mir_const_qualif::get(tcx, DUMMY_SP, def_id);
let cx = ConstContext::with_tables(tcx, tcx.item_tables(def_id));
let id = tcx.hir.as_local_node_id(def_id).unwrap();
let body = tcx.hir.body_owned_by(id);
cx.eval(&tcx.hir.body(body).value)
let body = if let Some(id) = tcx.hir.as_local_node_id(def_id) {
ty::queries::mir_const_qualif::get(tcx, DUMMY_SP, def_id);
tcx.hir.body(tcx.hir.body_owned_by(id))
} else {
tcx.sess.cstore.maybe_get_item_body(tcx, def_id).unwrap()
};
cx.eval(&body.value)
}

2
src/librustc_driver/driver.rs
View file

@ -900,6 +900,8 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
let mut extern_providers = ty::maps::Providers::default();
cstore::provide(&mut extern_providers);
ty::provide_extern(&mut extern_providers);
// FIXME(eddyb) get rid of this once we replace const_eval with miri.
rustc_const_eval::provide(&mut extern_providers);
TyCtxt::create_and_enter(sess,
local_providers,

11
src/librustc_incremental/persist/dirty_clean.rs
View file

@ -266,6 +266,17 @@ impl<'a, 'tcx, 'm> intravisit::Visitor<'tcx> for DirtyCleanMetadataVisitor<'a, '
intravisit::walk_item(self, item);
}
fn visit_variant(&mut self,
variant: &'tcx hir::Variant,
generics: &'tcx hir::Generics,
parent_id: ast::NodeId) {
if let Some(e) = variant.node.disr_expr {
self.check_item(e.node_id, variant.span);
}
intravisit::walk_variant(self, variant, generics, parent_id);
}
fn visit_variant_data(&mut self,
variant_data: &'tcx hir::VariantData,
_: ast::Name,

24
src/librustc_metadata/decoder.rs
View file

@ -511,11 +511,7 @@ impl<'a, 'tcx> CrateMetadata {
def
}
fn get_variant(&self,
item: &Entry<'tcx>,
index: DefIndex,
tcx: TyCtxt<'a, 'tcx, 'tcx>)
-> (ty::VariantDef, Option<DefIndex>) {
fn get_variant(&self, item: &Entry, index: DefIndex) -> ty::VariantDef {
let data = match item.kind {
EntryKind::Variant(data) |
EntryKind::Struct(data, _) |
@ -523,13 +519,7 @@ impl<'a, 'tcx> CrateMetadata {
_ => bug!(),
};
if let ty::VariantDiscr::Explicit(def_id) = data.discr {
// The original crate wouldn't have compiled if this is missing.
let result = Ok(data.evaluated_discr.unwrap());
tcx.maps.monomorphic_const_eval.borrow_mut().insert(def_id, result);
}
(ty::VariantDef {
ty::VariantDef {
did: self.local_def_id(data.struct_ctor.unwrap_or(index)),
name: self.item_name(index),
fields: item.children.decode(self).map(|index| {
@ -542,7 +532,7 @@ impl<'a, 'tcx> CrateMetadata {
}).collect(),
discr: data.discr,
ctor_kind: data.ctor_kind,
}, data.struct_ctor)
}
}
pub fn get_adt_def(&self,
@ -561,15 +551,11 @@ impl<'a, 'tcx> CrateMetadata {
item.children
.decode(self)
.map(|index| {
let (variant, struct_ctor) =
self.get_variant(&self.entry(index), index, tcx);
assert_eq!(struct_ctor, None);
variant
self.get_variant(&self.entry(index), index)
})
.collect()
} else {
let (variant, _struct_ctor) = self.get_variant(&item, item_id, tcx);
vec![variant]
vec![self.get_variant(&item, item_id)]
};
let (kind, repr) = match item.kind {
EntryKind::Enum(repr) => (ty::AdtKind::Enum, repr),

46
src/librustc_metadata/encoder.rs
View file

@ -269,12 +269,6 @@ impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
let data = VariantData {
ctor_kind: variant.ctor_kind,
discr: variant.discr,
evaluated_discr: match variant.discr {
ty::VariantDiscr::Explicit(def_id) => {
ty::queries::monomorphic_const_eval::get(tcx, DUMMY_SP, def_id).ok()
}
ty::VariantDiscr::Relative(_) => None
},
struct_ctor: None,
};
@ -408,7 +402,6 @@ impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
let data = VariantData {
ctor_kind: variant.ctor_kind,
discr: variant.discr,
evaluated_discr: None,
struct_ctor: Some(def_id.index),
};
@ -697,7 +690,6 @@ impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
EntryKind::Struct(self.lazy(&VariantData {
ctor_kind: variant.ctor_kind,
discr: variant.discr,
evaluated_discr: None,
struct_ctor: struct_ctor,
}), repr_options)
}
@ -708,7 +700,6 @@ impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
EntryKind::Union(self.lazy(&VariantData {
ctor_kind: variant.ctor_kind,
discr: variant.discr,
evaluated_discr: None,
struct_ctor: None,
}), repr_options)
}
@ -1037,6 +1028,17 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for EncodeVisitor<'a, 'b, 'tcx> {
EntryBuilder::encode_info_for_foreign_item,
(def_id, ni));
}
fn visit_variant(&mut self,
v: &'tcx hir::Variant,
g: &'tcx hir::Generics,
id: ast::NodeId) {
intravisit::walk_variant(self, v, g, id);
if let Some(discr) = v.node.disr_expr {
let def_id = self.index.tcx.hir.body_owner_def_id(discr);
self.index.record(def_id, EntryBuilder::encode_info_for_embedded_const, def_id);
}
}
fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
intravisit::walk_generics(self, generics);
self.index.encode_info_for_generics(generics);
@ -1160,6 +1162,32 @@ impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
}
}
fn encode_info_for_embedded_const(&mut self, def_id: DefId) -> Entry<'tcx> {
debug!("EntryBuilder::encode_info_for_embedded_const({:?})", def_id);
let tcx = self.tcx;
let id = tcx.hir.as_local_node_id(def_id).unwrap();
let body = tcx.hir.body_owned_by(id);
Entry {
kind: EntryKind::Const(ty::queries::mir_const_qualif::get(tcx, DUMMY_SP, def_id)),
visibility: self.lazy(&ty::Visibility::Public),
span: self.lazy(&tcx.def_span(def_id)),
attributes: LazySeq::empty(),
children: LazySeq::empty(),
stability: None,
deprecation: None,
ty: Some(self.encode_item_type(def_id)),
inherent_impls: LazySeq::empty(),
variances: LazySeq::empty(),
generics: Some(self.encode_generics(def_id)),
predicates: Some(self.encode_predicates(def_id)),
ast: Some(self.encode_body(body)),
mir: self.encode_mir(def_id),
}
}
fn encode_attributes(&mut self, attrs: &[ast::Attribute]) -> LazySeq<ast::Attribute> {
// NOTE: This must use lazy_seq_from_slice(), not lazy_seq() because
// we really on the HashStable specialization for [Attribute]

13
src/librustc_metadata/schema.rs
View file

@ -15,7 +15,6 @@ use rustc::hir;
use rustc::hir::def::{self, CtorKind};
use rustc::hir::def_id::{DefIndex, DefId};
use rustc::ich::StableHashingContext;
use rustc::middle::const_val::ConstVal;
use rustc::middle::cstore::{DepKind, LinkagePreference, NativeLibrary};
use rustc::middle::lang_items;
use rustc::mir;
@ -271,9 +270,9 @@ pub enum EntryKind<'tcx> {
Type,
Enum(ReprOptions),
Field,
Variant(Lazy<VariantData<'tcx>>),
Struct(Lazy<VariantData<'tcx>>, ReprOptions),
Union(Lazy<VariantData<'tcx>>, ReprOptions),
Variant(Lazy<VariantData>),
Struct(Lazy<VariantData>, ReprOptions),
Union(Lazy<VariantData>, ReprOptions),
Fn(Lazy<FnData>),
ForeignFn(Lazy<FnData>),
Mod(Lazy<ModData>),
@ -374,20 +373,18 @@ pub struct FnData {
impl_stable_hash_for!(struct FnData { constness, arg_names });
#[derive(RustcEncodable, RustcDecodable)]
pub struct VariantData<'tcx> {
pub struct VariantData {
pub ctor_kind: CtorKind,
pub discr: ty::VariantDiscr,
pub evaluated_discr: Option<ConstVal<'tcx>>,
/// If this is a struct's only variant, this
/// is the index of the "struct ctor" item.
pub struct_ctor: Option<DefIndex>,
}
impl_stable_hash_for!(struct VariantData<'tcx> {
impl_stable_hash_for!(struct VariantData {
ctor_kind,
discr,
evaluated_discr,
struct_ctor
});

20
src/librustc_trans/adt.rs
View file

@ -41,8 +41,6 @@
//! used unboxed and any field can have pointers (including mutable)
//! taken to it, implementing them for Rust seems difficult.
use super::Disr;
use std;
use llvm::{ValueRef, True, IntEQ, IntNE};
@ -347,31 +345,31 @@ fn load_discr(bcx: &Builder, ity: layout::Integer, ptr: ValueRef,
/// Set the discriminant for a new value of the given case of the given
/// representation.
pub fn trans_set_discr<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, t: Ty<'tcx>, val: ValueRef, to: Disr) {
pub fn trans_set_discr<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, t: Ty<'tcx>, val: ValueRef, to: u64) {
let l = bcx.ccx.layout_of(t);
match *l {
layout::CEnum{ discr, min, max, .. } => {
assert_discr_in_range(Disr(min), Disr(max), to);
bcx.store(C_integral(Type::from_integer(bcx.ccx, discr), to.0, true),
assert_discr_in_range(min, max, to);
bcx.store(C_integral(Type::from_integer(bcx.ccx, discr), to, true),
val, None);
}
layout::General{ discr, .. } => {
bcx.store(C_integral(Type::from_integer(bcx.ccx, discr), to.0, true),
bcx.store(C_integral(Type::from_integer(bcx.ccx, discr), to, true),
bcx.struct_gep(val, 0), None);
}
layout::Univariant { .. }
| layout::UntaggedUnion { .. }
| layout::Vector { .. } => {
assert_eq!(to, Disr(0));
assert_eq!(to, 0);
}
layout::RawNullablePointer { nndiscr, .. } => {
if to.0 != nndiscr {
if to != nndiscr {
let llptrty = val_ty(val).element_type();
bcx.store(C_null(llptrty), val, None);
}
}
layout::StructWrappedNullablePointer { nndiscr, ref discrfield, ref nonnull, .. } => {
if to.0 != nndiscr {
if to != nndiscr {
if target_sets_discr_via_memset(bcx) {
// Issue #34427: As workaround for LLVM bug on
// ARM, use memset of 0 on whole struct rather
@ -397,7 +395,7 @@ fn target_sets_discr_via_memset<'a, 'tcx>(bcx: &Builder<'a, 'tcx>) -> bool {
bcx.sess().target.target.arch == "arm" || bcx.sess().target.target.arch == "aarch64"
}
pub fn assert_discr_in_range(min: Disr, max: Disr, discr: Disr) {
pub fn assert_discr_in_range<D: PartialOrd>(min: D, max: D, discr: D) {
if min <= max {
assert!(min <= discr && discr <= max)
} else {
@ -415,7 +413,7 @@ fn roundup(x: u64, a: u32) -> u64 { let a = a as u64; ((x + (a - 1)) / a) * a }
/// (Not to be confused with `common::const_get_elt`, which operates on
/// raw LLVM-level structs and arrays.)
pub fn const_get_field<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>,
val: ValueRef, _discr: Disr,
val: ValueRef,
ix: usize) -> ValueRef {
let l = ccx.layout_of(t);
match *l {

82
src/librustc_trans/disr.rs
View file

@ -1,82 +0,0 @@
// Copyright 2012-2015 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::middle::const_val::ConstVal;
use rustc::ty::{self, TyCtxt};
use rustc_const_math::ConstInt;
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
pub struct Disr(pub u64);
impl Disr {
pub fn for_variant(tcx: TyCtxt,
def: &ty::AdtDef,
variant_index: usize) -> Self {
let mut explicit_index = variant_index;
let mut explicit_value = Disr(0);
loop {
match def.variants[explicit_index].discr {
ty::VariantDiscr::Relative(0) => break,
ty::VariantDiscr::Relative(distance) => {
explicit_index -= distance;
}
ty::VariantDiscr::Explicit(expr_did) => {
match tcx.maps.monomorphic_const_eval.borrow()[&expr_did] {
Ok(ConstVal::Integral(v)) => {
explicit_value = Disr::from(v);
break;
}
_ => {
explicit_index -= 1;
}
}
}
}
}
let distance = variant_index - explicit_index;
explicit_value.wrapping_add(Disr::from(distance))
}
pub fn wrapping_add(self, other: Self) -> Self {
Disr(self.0.wrapping_add(other.0))
}
}
impl ::std::ops::BitAnd for Disr {
type Output = Disr;
fn bitand(self, other: Self) -> Self {
Disr(self.0 & other.0)
}
}
impl From<ConstInt> for Disr {
fn from(i: ConstInt) -> Disr {
// FIXME: what if discr has 128 bit discr?
Disr(i.to_u128_unchecked() as u64)
}
}
impl From<usize> for Disr {
fn from(i: usize) -> Disr {
Disr(i as u64)
}
}
impl PartialOrd for Disr {
fn partial_cmp(&self, other: &Disr) -> Option<::std::cmp::Ordering> {
self.0.partial_cmp(&other.0)
}
}
impl Ord for Disr {
fn cmp(&self, other: &Disr) -> ::std::cmp::Ordering {
self.0.cmp(&other.0)
}
}

2
src/librustc_trans/lib.rs
View file

@ -67,7 +67,6 @@ pub use rustc::lint;
pub use rustc::util;
pub use base::trans_crate;
pub use disr::Disr;
pub mod back {
pub use rustc::hir::svh;
@ -118,7 +117,6 @@ mod consts;
mod context;
mod debuginfo;
mod declare;
mod disr;
mod glue;
mod intrinsic;
mod machine;

13
src/librustc_trans/mir/constant.rs
View file

@ -22,7 +22,7 @@ use rustc::ty::layout::{self, LayoutTyper};
use rustc::ty::cast::{CastTy, IntTy};
use rustc::ty::subst::{Kind, Substs, Subst};
use rustc_data_structures::indexed_vec::{Idx, IndexVec};
use {abi, adt, base, Disr, machine};
use {abi, adt, base, machine};
use callee;
use builder::Builder;
use common::{self, CrateContext, const_get_elt, val_ty};
@ -428,7 +428,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
}
mir::ProjectionElem::Field(ref field, _) => {
let llprojected = adt::const_get_field(self.ccx, tr_base.ty, base.llval,
Disr(0), field.index());
field.index());
let llextra = if is_sized {
ptr::null_mut()
} else {
@ -987,13 +987,14 @@ fn trans_const<'a, 'tcx>(
layout::CEnum { discr: d, min, max, .. } => {
let discr = match *kind {
mir::AggregateKind::Adt(adt_def, _, _, _) => {
Disr::for_variant(ccx.tcx(), adt_def, variant_index)
adt_def.discriminant_for_variant(ccx.tcx(), variant_index)
.to_u128_unchecked() as u64
},
_ => Disr(0),
_ => 0,
};
assert_eq!(vals.len(), 0);
adt::assert_discr_in_range(Disr(min), Disr(max), discr);
C_integral(Type::from_integer(ccx, d), discr.0, true)
adt::assert_discr_in_range(min, max, discr);
C_integral(Type::from_integer(ccx, d), discr, true)
}
layout::General { discr: d, ref variants, .. } => {
let variant = &variants[variant_index];

6
src/librustc_trans/mir/rvalue.rs
View file

@ -28,7 +28,6 @@ use type_::Type;
use type_of;
use tvec;
use value::Value;
use Disr;
use super::MirContext;
use super::constant::const_scalar_checked_binop;
@ -107,9 +106,10 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
mir::Rvalue::Aggregate(ref kind, ref operands) => {
match *kind {
mir::AggregateKind::Adt(adt_def, variant_index, substs, active_field_index) => {
let disr = Disr::for_variant(bcx.tcx(), adt_def, variant_index);
let discr = adt_def.discriminant_for_variant(bcx.tcx(), variant_index)
.to_u128_unchecked() as u64;
let dest_ty = dest.ty.to_ty(bcx.tcx());
adt::trans_set_discr(&bcx, dest_ty, dest.llval, disr);
adt::trans_set_discr(&bcx, dest_ty, dest.llval, discr);
for (i, operand) in operands.iter().enumerate() {
let op = self.trans_operand(&bcx, operand);
// Do not generate stores and GEPis for zero-sized fields.

3
src/librustc_trans/mir/statement.rs
View file

@ -18,7 +18,6 @@ use builder::Builder;
use super::MirContext;
use super::LocalRef;
use super::super::adt;
use super::super::disr::Disr;
impl<'a, 'tcx> MirContext<'a, 'tcx> {
pub fn trans_statement(&mut self,
@ -65,7 +64,7 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
adt::trans_set_discr(&bcx,
ty,
lvalue_transed.llval,
Disr::from(variant_index));
variant_index as u64);
bcx
}
mir::StatementKind::StorageLive(ref lvalue) => {

6
src/test/incremental/hashes/enum_defs.rs
View file

@ -27,6 +27,7 @@
#![allow(warnings)]
#![feature(rustc_attrs)]
#![feature(stmt_expr_attributes)]
#![crate_type="rlib"]
@ -125,9 +126,12 @@ enum EnumChangeValueCStyleVariant0 {
enum EnumChangeValueCStyleVariant0 {
Variant1,
#[rustc_metadata_clean(cfg="cfail2")]
#[rustc_metadata_clean(cfg="cfail3")]
Variant2 =
#[rustc_metadata_dirty(cfg="cfail2")]
#[rustc_metadata_clean(cfg="cfail3")]
Variant2 = 22,
22,
}
#[cfg(cfail1)]