Skip to content

Commit ecdd51b

Browse files
borsbors
authored
Auto merge of #35267 - eddyb:ty-hash, r=nikomatsakis
Rewrite TypeId computation to not miss anything and work cross-crate. Fixes #33703 and also some soundness holes in `Any` due to `TypeId` ignoring most lifetimes.
2 parents 7bf54f9 + d42da7b commit ecdd51b

File tree

7 files changed

+248
-191
lines changed

7 files changed

+248
-191
lines changed

‎src/librustc/ty/util.rs‎

Lines changed: 146 additions & 143 deletions
Original file line numberDiff line numberDiff line change
@@ -10,21 +10,22 @@
1010

1111
//! misc. type-system utilities too small to deserve their own file
1212
13-
use hir::svh::Svh;
1413
use hir::def_id::DefId;
1514
use ty::subst;
1615
use infer::InferCtxt;
1716
use hir::pat_util;
1817
use traits::{self, ProjectionMode};
1918
use ty::{self, Ty, TyCtxt, TypeAndMut, TypeFlags, TypeFoldable};
2019
use ty::{Disr, ParameterEnvironment};
20+
use ty::fold::TypeVisitor;
2121
use ty::layout::{Layout, LayoutError};
2222
use ty::TypeVariants::*;
2323

2424
use rustc_const_math::{ConstInt, ConstIsize, ConstUsize};
2525

2626
use std::cmp;
2727
use std::hash::{Hash, SipHasher, Hasher};
28+
use std::intrinsics;
2829
use syntax::ast::{self, Name};
2930
use syntax::attr::{self, SignedInt, UnsignedInt};
3031
use syntax_pos::Span;
@@ -350,148 +351,13 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
350351

351352
/// Creates a hash of the type `Ty` which will be the same no matter what crate
352353
/// context it's calculated within. This is used by the `type_id` intrinsic.
353-
pub fn hash_crate_independent(self, ty: Ty<'tcx>, svh: &Svh) -> u64 {
354-
let mut state = SipHasher::new();
355-
helper(self, ty, svh, &mut state);
356-
return state.finish();
357-
358-
fn helper<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
359-
ty: Ty<'tcx>, svh: &Svh,
360-
state: &mut SipHasher) {
361-
macro_rules! byte { ($b:expr) => { ($b as u8).hash(state) } }
362-
macro_rules! hash { ($e:expr) => { $e.hash(state) } }
363-
364-
let region = |state: &mut SipHasher, r: ty::Region| {
365-
match r {
366-
ty::ReStatic | ty::ReErased => {}
367-
ty::ReLateBound(db, ty::BrAnon(i)) => {
368-
db.hash(state);
369-
i.hash(state);
370-
}
371-
ty::ReEmpty |
372-
ty::ReEarlyBound(..) |
373-
ty::ReLateBound(..) |
374-
ty::ReFree(..) |
375-
ty::ReScope(..) |
376-
ty::ReVar(..) |
377-
ty::ReSkolemized(..) => {
378-
bug!("unexpected region found when hashing a type")
379-
}
380-
}
381-
};
382-
let did = |state: &mut SipHasher, did: DefId| {
383-
let h = if did.is_local() {
384-
svh.clone()
385-
} else {
386-
tcx.sess.cstore.crate_hash(did.krate)
387-
};
388-
h.hash(state);
389-
did.index.hash(state);
390-
};
391-
let mt = |state: &mut SipHasher, mt: TypeAndMut| {
392-
mt.mutbl.hash(state);
393-
};
394-
let fn_sig = |state: &mut SipHasher, sig: &ty::Binder<ty::FnSig<'tcx>>| {
395-
let sig = tcx.anonymize_late_bound_regions(sig).0;
396-
for a in &sig.inputs { helper(tcx, *a, svh, state); }
397-
if let ty::FnConverging(output) = sig.output {
398-
helper(tcx, output, svh, state);
399-
}
400-
};
401-
ty.maybe_walk(|ty| {
402-
match ty.sty {
403-
TyBool => byte!(2),
404-
TyChar => byte!(3),
405-
TyInt(i) => {
406-
byte!(4);
407-
hash!(i);
408-
}
409-
TyUint(u) => {
410-
byte!(5);
411-
hash!(u);
412-
}
413-
TyFloat(f) => {
414-
byte!(6);
415-
hash!(f);
416-
}
417-
TyStr => {
418-
byte!(7);
419-
}
420-
TyEnum(d, _) => {
421-
byte!(8);
422-
did(state, d.did);
423-
}
424-
TyBox(_) => {
425-
byte!(9);
426-
}
427-
TyArray(_, n) => {
428-
byte!(10);
429-
n.hash(state);
430-
}
431-
TySlice(_) => {
432-
byte!(11);
433-
}
434-
TyRawPtr(m) => {
435-
byte!(12);
436-
mt(state, m);
437-
}
438-
TyRef(r, m) => {
439-
byte!(13);
440-
region(state, *r);
441-
mt(state, m);
442-
}
443-
TyFnDef(def_id, _, _) => {
444-
byte!(14);
445-
hash!(def_id);
446-
}
447-
TyFnPtr(ref b) => {
448-
byte!(15);
449-
hash!(b.unsafety);
450-
hash!(b.abi);
451-
fn_sig(state, &b.sig);
452-
return false;
453-
}
454-
TyTrait(ref data) => {
455-
byte!(17);
456-
did(state, data.principal_def_id());
457-
hash!(data.bounds);
458-
459-
let principal = tcx.anonymize_late_bound_regions(&data.principal).0;
460-
for subty in &principal.substs.types {
461-
helper(tcx, subty, svh, state);
462-
}
463-
464-
return false;
465-
}
466-
TyStruct(d, _) => {
467-
byte!(18);
468-
did(state, d.did);
469-
}
470-
TyTuple(ref inner) => {
471-
byte!(19);
472-
hash!(inner.len());
473-
}
474-
TyParam(p) => {
475-
byte!(20);
476-
hash!(p.space);
477-
hash!(p.idx);
478-
hash!(p.name.as_str());
479-
}
480-
TyInfer(_) => bug!(),
481-
TyError => byte!(21),
482-
TyClosure(d, _) => {
483-
byte!(22);
484-
did(state, d);
485-
}
486-
TyProjection(ref data) => {
487-
byte!(23);
488-
did(state, data.trait_ref.def_id);
489-
hash!(data.item_name.as_str());
490-
}
491-
}
492-
true
493-
});
494-
}
354+
pub fn type_id_hash(self, ty: Ty<'tcx>) -> u64 {
355+
let mut hasher = TypeIdHasher {
356+
tcx: self,
357+
state: SipHasher::new()
358+
};
359+
hasher.visit_ty(ty);
360+
hasher.state.finish()
495361
}
496362

497363
/// Returns true if this ADT is a dtorck type.
@@ -525,6 +391,143 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
525391
}
526392
}
527393

394+
struct TypeIdHasher<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
395+
tcx: TyCtxt<'a, 'gcx, 'tcx>,
396+
state: SipHasher
397+
}
398+
399+
impl<'a, 'gcx, 'tcx> TypeIdHasher<'a, 'gcx, 'tcx> {
400+
fn hash<T: Hash>(&mut self, x: T) {
401+
x.hash(&mut self.state);
402+
}
403+
404+
fn hash_discriminant_u8<T>(&mut self, x: &T) {
405+
let v = unsafe {
406+
intrinsics::discriminant_value(x)
407+
};
408+
let b = v as u8;
409+
assert_eq!(v, b as u64);
410+
self.hash(b)
411+
}
412+
413+
fn def_id(&mut self, did: DefId) {
414+
// Hash the crate identification information.
415+
let name = self.tcx.crate_name(did.krate);
416+
let disambiguator = self.tcx.crate_disambiguator(did.krate);
417+
self.hash((name, disambiguator));
418+
419+
// Hash the item path within that crate.
420+
// FIXME(#35379) This should use a deterministic
421+
// DefPath hashing mechanism, not the DefIndex.
422+
self.hash(did.index);
423+
}
424+
}
425+
426+
impl<'a, 'gcx, 'tcx> TypeVisitor<'tcx> for TypeIdHasher<'a, 'gcx, 'tcx> {
427+
fn visit_ty(&mut self, ty: Ty<'tcx>) -> bool {
428+
// Distinguish between the Ty variants uniformly.
429+
self.hash_discriminant_u8(&ty.sty);
430+
431+
match ty.sty {
432+
TyInt(i) => self.hash(i),
433+
TyUint(u) => self.hash(u),
434+
TyFloat(f) => self.hash(f),
435+
TyStruct(d, _) |
436+
TyEnum(d, _) => self.def_id(d.did),
437+
TyArray(_, n) => self.hash(n),
438+
TyRawPtr(m) |
439+
TyRef(_, m) => self.hash(m.mutbl),
440+
TyClosure(def_id, _) |
441+
TyFnDef(def_id, _, _) => self.def_id(def_id),
442+
TyFnPtr(f) => {
443+
self.hash(f.unsafety);
444+
self.hash(f.abi);
445+
self.hash(f.sig.variadic());
446+
}
447+
TyTrait(ref data) => {
448+
// Trait objects have a list of projection bounds
449+
// that are not guaranteed to be sorted in an order
450+
// that gets preserved across crates, so we need
451+
// to sort them again by the name, in string form.
452+
453+
// Hash the whole principal trait ref.
454+
self.def_id(data.principal_def_id());
455+
data.principal.visit_with(self);
456+
457+
// Hash region and builtin bounds.
458+
data.bounds.region_bound.visit_with(self);
459+
self.hash(data.bounds.builtin_bounds);
460+
461+
// Only projection bounds are left, sort and hash them.
462+
let mut projection_bounds: Vec<_> = data.bounds.projection_bounds
463+
.iter()
464+
.map(|b| (b.item_name().as_str(), b))
465+
.collect();
466+
projection_bounds.sort_by_key(|&(ref name, _)| name.clone());
467+
for (name, bound) in projection_bounds {
468+
self.def_id(bound.0.projection_ty.trait_ref.def_id);
469+
self.hash(name);
470+
bound.visit_with(self);
471+
}
472+
473+
// Bypass super_visit_with, we've visited everything.
474+
return false;
475+
}
476+
TyTuple(tys) => {
477+
self.hash(tys.len());
478+
}
479+
TyParam(p) => {
480+
self.hash(p.space);
481+
self.hash(p.idx);
482+
self.hash(p.name.as_str());
483+
}
484+
TyProjection(ref data) => {
485+
self.def_id(data.trait_ref.def_id);
486+
self.hash(data.item_name.as_str());
487+
}
488+
TyBool |
489+
TyChar |
490+
TyStr |
491+
TyBox(_) |
492+
TySlice(_) |
493+
TyError => {}
494+
TyInfer(_) => bug!()
495+
}
496+
497+
ty.super_visit_with(self)
498+
}
499+
500+
fn visit_region(&mut self, r: ty::Region) -> bool {
501+
match r {
502+
ty::ReStatic | ty::ReErased => {
503+
self.hash::<u32>(0);
504+
}
505+
ty::ReLateBound(db, ty::BrAnon(i)) => {
506+
assert!(db.depth > 0);
507+
self.hash::<u32>(db.depth);
508+
self.hash(i);
509+
}
510+
ty::ReEmpty |
511+
ty::ReEarlyBound(..) |
512+
ty::ReLateBound(..) |
513+
ty::ReFree(..) |
514+
ty::ReScope(..) |
515+
ty::ReVar(..) |
516+
ty::ReSkolemized(..) => {
517+
bug!("unexpected region found when hashing a type")
518+
}
519+
}
520+
false
521+
}
522+
523+
fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, x: &ty::Binder<T>) -> bool {
524+
// Anonymize late-bound regions so that, for example:
525+
// `for<'a, b> fn(&'a &'b T)` and `for<'a, b> fn(&'b &'a T)`
526+
// result in the same TypeId (the two types are equivalent).
527+
self.tcx.anonymize_late_bound_regions(x).super_visit_with(self)
528+
}
529+
}
530+
528531
impl<'a, 'tcx> ty::TyS<'tcx> {
529532
fn impls_bound(&'tcx self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
530533
param_env: &ParameterEnvironment<'tcx>,

‎src/librustc_trans/intrinsic.rs‎

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -406,9 +406,7 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
406406
C_str_slice(ccx, ty_name)
407407
}
408408
(_, "type_id") => {
409-
let hash = ccx.tcx().hash_crate_independent(*substs.types.get(FnSpace, 0),
410-
&ccx.link_meta().crate_hash);
411-
C_u64(ccx, hash)
409+
C_u64(ccx, ccx.tcx().type_id_hash(*substs.types.get(FnSpace, 0)))
412410
}
413411
(_, "init_dropped") => {
414412
let tp_ty = *substs.types.get(FnSpace, 0);

‎src/test/run-pass/auxiliary/typeid-intrinsic-aux1.rs‎

Lines changed: 11 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -21,14 +21,16 @@ pub struct E(Result<&'static str, isize>);
2121
pub type F = Option<isize>;
2222
pub type G = usize;
2323
pub type H = &'static str;
24+
pub type I = Box<Fn()>;
2425

25-
pub unsafe fn id_A() -> TypeId { TypeId::of::<A>() }
26-
pub unsafe fn id_B() -> TypeId { TypeId::of::<B>() }
27-
pub unsafe fn id_C() -> TypeId { TypeId::of::<C>() }
28-
pub unsafe fn id_D() -> TypeId { TypeId::of::<D>() }
29-
pub unsafe fn id_E() -> TypeId { TypeId::of::<E>() }
30-
pub unsafe fn id_F() -> TypeId { TypeId::of::<F>() }
31-
pub unsafe fn id_G() -> TypeId { TypeId::of::<G>() }
32-
pub unsafe fn id_H() -> TypeId { TypeId::of::<H>() }
26+
pub fn id_A() -> TypeId { TypeId::of::<A>() }
27+
pub fn id_B() -> TypeId { TypeId::of::<B>() }
28+
pub fn id_C() -> TypeId { TypeId::of::<C>() }
29+
pub fn id_D() -> TypeId { TypeId::of::<D>() }
30+
pub fn id_E() -> TypeId { TypeId::of::<E>() }
31+
pub fn id_F() -> TypeId { TypeId::of::<F>() }
32+
pub fn id_G() -> TypeId { TypeId::of::<G>() }
33+
pub fn id_H() -> TypeId { TypeId::of::<H>() }
34+
pub fn id_I() -> TypeId { TypeId::of::<I>() }
3335

34-
pub unsafe fn foo<T: Any>() -> TypeId { TypeId::of::<T>() }
36+
pub fn foo<T: Any>() -> TypeId { TypeId::of::<T>() }

‎src/test/run-pass/auxiliary/typeid-intrinsic-aux2.rs‎

Lines changed: 11 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -21,14 +21,16 @@ pub struct E(Result<&'static str, isize>);
2121
pub type F = Option<isize>;
2222
pub type G = usize;
2323
pub type H = &'static str;
24+
pub type I = Box<Fn()>;
2425

25-
pub unsafe fn id_A() -> TypeId { TypeId::of::<A>() }
26-
pub unsafe fn id_B() -> TypeId { TypeId::of::<B>() }
27-
pub unsafe fn id_C() -> TypeId { TypeId::of::<C>() }
28-
pub unsafe fn id_D() -> TypeId { TypeId::of::<D>() }
29-
pub unsafe fn id_E() -> TypeId { TypeId::of::<E>() }
30-
pub unsafe fn id_F() -> TypeId { TypeId::of::<F>() }
31-
pub unsafe fn id_G() -> TypeId { TypeId::of::<G>() }
32-
pub unsafe fn id_H() -> TypeId { TypeId::of::<H>() }
26+
pub fn id_A() -> TypeId { TypeId::of::<A>() }
27+
pub fn id_B() -> TypeId { TypeId::of::<B>() }
28+
pub fn id_C() -> TypeId { TypeId::of::<C>() }
29+
pub fn id_D() -> TypeId { TypeId::of::<D>() }
30+
pub fn id_E() -> TypeId { TypeId::of::<E>() }
31+
pub fn id_F() -> TypeId { TypeId::of::<F>() }
32+
pub fn id_G() -> TypeId { TypeId::of::<G>() }
33+
pub fn id_H() -> TypeId { TypeId::of::<H>() }
34+
pub fn id_I() -> TypeId { TypeId::of::<I>() }
3335

34-
pub unsafe fn foo<T:Any>() -> TypeId { TypeId::of::<T>() }
36+
pub fn foo<T: Any>() -> TypeId { TypeId::of::<T>() }

0 commit comments

Comments
 (0)