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Rework stability annotation pass
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@petrochenkov
petrochenkov committed Nov 17, 2015
1 parent b2f5393 commit 52acc05
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Showing 3 changed files with 163 additions and 137 deletions.
277 changes: 147 additions & 130 deletions src/librustc/middle/stability.rs
View file
Expand Up @@ -12,6 +12,7 @@
//! propagating default levels lexically from parent to children ast nodes.

pub use self::StabilityLevel::*;
use self::AnnotationKind::*;

use session::Session;
use lint;
Expand All @@ -30,8 +31,8 @@ use syntax::attr::{self, Stability, AttrMetaMethods};
use util::nodemap::{DefIdMap, FnvHashSet, FnvHashMap};

use rustc_front::hir;
use rustc_front::hir::{FnDecl, Block, Crate, Item, Generics, StructField, Variant};
use rustc_front::visit::{self, FnKind, Visitor};
use rustc_front::hir::{Block, Crate, Item, Generics, StructField, Variant};
use rustc_front::visit::{self, Visitor};

use std::mem::replace;
use std::cmp::Ordering;
Expand All @@ -48,6 +49,16 @@ impl StabilityLevel {
}
}

#[derive(PartialEq)]
enum AnnotationKind {
// Annotation is required if not inherited from unstable parents
AnnRequired,
// Annotation is useless, reject it
AnnProhibited,
// Annotation itself is useless, but it can be propagated to children
AnnContainer,
}

/// A stability index, giving the stability level for items and methods.
pub struct Index<'tcx> {
/// This is mostly a cache, except the stabilities of local items
Expand All @@ -64,174 +75,180 @@ struct Annotator<'a, 'tcx: 'a> {
index: &'a mut Index<'tcx>,
parent: Option<&'tcx Stability>,
export_map: &'a PublicItems,
in_trait_impl: bool,
in_enum: bool,
}

impl<'a, 'tcx: 'a> Annotator<'a, 'tcx> {
// Determine the stability for a node based on its attributes and inherited
// stability. The stability is recorded in the index and used as the parent.
fn annotate<F>(&mut self, id: NodeId, use_parent: bool,
attrs: &Vec<Attribute>, item_sp: Span, f: F, required: bool) where
F: FnOnce(&mut Annotator),
fn annotate<F>(&mut self, id: NodeId, attrs: &Vec<Attribute>,
item_sp: Span, kind: AnnotationKind, visit_children: F)
where F: FnOnce(&mut Annotator)
{
if self.index.staged_api[&LOCAL_CRATE] {
debug!("annotate(id = {:?}, attrs = {:?})", id, attrs);
match attr::find_stability(self.tcx.sess.diagnostic(), attrs, item_sp) {
Some(mut stab) => {
debug!("annotate: found {:?}", stab);
// if parent is deprecated and we're not, inherit this by merging
// deprecated_since and its reason.
if let Some(parent_stab) = self.parent {
if parent_stab.depr.is_some()
&& stab.depr.is_none() {
stab.depr = parent_stab.depr.clone()
}
if let Some(mut stab) = attr::find_stability(self.tcx.sess.diagnostic(),
attrs, item_sp) {
// Error if prohibited, or can't inherit anything from a container
if kind == AnnProhibited ||
kind == AnnContainer && stab.level.is_stable() && stab.depr.is_none() {
self.tcx.sess.span_err(item_sp, "This stability annotation is useless");
}

debug!("annotate: found {:?}", stab);
// If parent is deprecated and we're not, inherit this by merging
// deprecated_since and its reason.
if let Some(parent_stab) = self.parent {
if parent_stab.depr.is_some() && stab.depr.is_none() {
stab.depr = parent_stab.depr.clone()
}
}

let stab = self.tcx.intern_stability(stab);

// Check if deprecated_since < stable_since. If it is,
// this is *almost surely* an accident.
let deprecated_predates_stable = match (&stab.depr, &stab.level) {
(&Some(attr::Deprecation {since: ref dep_since, ..}),
&attr::Stable {since: ref stab_since}) => {
// explicit version of iter::order::lt to handle parse errors properly
let mut is_less = false;
for (dep_v, stab_v) in dep_since.split(".").zip(stab_since.split(".")) {
match (dep_v.parse::<u64>(), stab_v.parse::<u64>()) {
(Ok(dep_v), Ok(stab_v)) => match dep_v.cmp(&stab_v) {
Ordering::Less => {
is_less = true;
break;
}
Ordering::Equal => { continue; }
Ordering::Greater => { break; }
},
_ => {
self.tcx.sess.span_err(item_sp,
"Invalid stability or deprecation version found");
// act like it isn't less because the question is now
// nonsensical, and this makes us not do anything else
// interesting.
break;
}
let stab = self.tcx.intern_stability(stab);

// Check if deprecated_since < stable_since. If it is,
// this is *almost surely* an accident.
if let (&Some(attr::Deprecation {since: ref dep_since, ..}),
&attr::Stable {since: ref stab_since}) = (&stab.depr, &stab.level) {
// Explicit version of iter::order::lt to handle parse errors properly
for (dep_v, stab_v) in dep_since.split(".").zip(stab_since.split(".")) {
if let (Ok(dep_v), Ok(stab_v)) = (dep_v.parse::<u64>(), stab_v.parse()) {
match dep_v.cmp(&stab_v) {
Ordering::Less => {
self.tcx.sess.span_err(item_sp, "An API can't be stabilized \
after it is deprecated");
break
}
Ordering::Equal => continue,
Ordering::Greater => break,
}
is_less
},
_ => false,
};

if deprecated_predates_stable {
self.tcx.sess.span_err(item_sp,
"An API can't be stabilized after it is deprecated");
} else {
// Act like it isn't less because the question is now nonsensical,
// and this makes us not do anything else interesting.
self.tcx.sess.span_err(item_sp, "Invalid stability or deprecation \
version found");
break
}
}
}

let def_id = self.tcx.map.local_def_id(id);
self.index.map.insert(def_id, Some(stab));

// Don't inherit #[stable(feature = "rust1", since = "1.0.0")]
if !stab.level.is_stable() {
let parent = replace(&mut self.parent, Some(stab));
f(self);
self.parent = parent;
} else {
f(self);
let def_id = self.tcx.map.local_def_id(id);
self.index.map.insert(def_id, Some(stab));

let parent = replace(&mut self.parent, Some(stab));
visit_children(self);
self.parent = parent;
} else {
debug!("annotate: not found, parent = {:?}", self.parent);
let mut is_error = kind == AnnRequired &&
self.export_map.contains(&id) &&
!self.tcx.sess.opts.test;
if let Some(stab) = self.parent {
if stab.level.is_unstable() {
let def_id = self.tcx.map.local_def_id(id);
self.index.map.insert(def_id, Some(stab));
is_error = false;
}
}
None => {
debug!("annotate: not found, use_parent = {:?}, parent = {:?}",
use_parent, self.parent);
if use_parent {
if let Some(stab) = self.parent {
let def_id = self.tcx.map.local_def_id(id);
self.index.map.insert(def_id, Some(stab));
} else if self.index.staged_api[&LOCAL_CRATE] && required
&& self.export_map.contains(&id)
&& !self.tcx.sess.opts.test {
self.tcx.sess.span_err(item_sp,
"This node does not \
have a stability attribute");
}
}
f(self);
if is_error {
self.tcx.sess.span_err(item_sp, "This node does not have \
a stability attribute");
}
visit_children(self);
}
} else {
// Emit warnings for non-staged-api crates. These should be errors.
// Emit errors for non-staged-api crates.
for attr in attrs {
let tag = attr.name();
if tag == "unstable" || tag == "stable" || tag == "deprecated" {
attr::mark_used(attr);
self.tcx.sess.span_err(attr.span(),
"stability attributes may not be used outside \
of the standard library");
self.tcx.sess.span_err(attr.span(), "stability attributes may not be used \
outside of the standard library");
}
}
f(self);
visit_children(self);
}
}
}

impl<'a, 'tcx, 'v> Visitor<'v> for Annotator<'a, 'tcx> {
fn visit_item(&mut self, i: &Item) {
// FIXME (#18969): the following is a hack around the fact
// that we cannot currently annotate the stability of
// `deriving`. Basically, we do *not* allow stability
// inheritance on trait implementations, so that derived
// implementations appear to be unannotated. This then allows
// derived implementations to be automatically tagged with the
// stability of the trait. This is WRONG, but expedient to get
// libstd stabilized for the 1.0 release.
let use_parent = match i.node {
hir::ItemImpl(_, _, _, Some(_), _, _) => false,
_ => true,
};

// In case of a `pub use <mod>;`, we should not error since the stability
// is inherited from the module itself
let required = match i.node {
hir::ItemUse(_) => i.vis != hir::Public,
_ => true
};

self.annotate(i.id, use_parent, &i.attrs, i.span,
|v| visit::walk_item(v, i), required);

if let hir::ItemStruct(ref sd, _) = i.node {
if !sd.is_struct() {
self.annotate(sd.id(), true, &i.attrs, i.span, |_| {}, true)
let orig_in_trait_impl = self.in_trait_impl;
let orig_in_enum = self.in_enum;
let mut kind = AnnRequired;
match i.node {
// Inherent impls and foreign modules serve only as containers for other items,
// they don't have their own stability. They still can be annotated as unstable
// and propagate this unstability to children, but this annotation is completely
// optional. They inherit stability from their parents when unannotated.
hir::ItemImpl(_, _, _, None, _, _) | hir::ItemForeignMod(..) => {
self.in_trait_impl = false;
kind = AnnContainer;
}
hir::ItemImpl(_, _, _, Some(_), _, _) => {
self.in_trait_impl = true;
}
hir::ItemStruct(ref sd, _) => {
self.in_enum = false;
if !sd.is_struct() {
self.annotate(sd.id(), &i.attrs, i.span, AnnRequired, |_| {})
}
}
hir::ItemEnum(..) => {
self.in_enum = true;
}
_ => {}
}
}

fn visit_fn(&mut self, _: FnKind<'v>, _: &'v FnDecl,
_: &'v Block, _: Span, _: NodeId) {
// Items defined in a function body have no reason to have
// a stability attribute, so we don't recurse.
self.annotate(i.id, &i.attrs, i.span, kind, |v| {
visit::walk_item(v, i)
});
self.in_trait_impl = orig_in_trait_impl;
self.in_enum = orig_in_enum;
}

fn visit_trait_item(&mut self, ti: &hir::TraitItem) {
self.annotate(ti.id, true, &ti.attrs, ti.span,
|v| visit::walk_trait_item(v, ti), true);
self.annotate(ti.id, &ti.attrs, ti.span, AnnRequired, |v| {
visit::walk_trait_item(v, ti);
});
}

fn visit_impl_item(&mut self, ii: &hir::ImplItem) {
self.annotate(ii.id, true, &ii.attrs, ii.span,
|v| visit::walk_impl_item(v, ii), false);
let kind = if self.in_trait_impl { AnnProhibited } else { AnnRequired };
self.annotate(ii.id, &ii.attrs, ii.span, kind, |v| {
visit::walk_impl_item(v, ii);
});
}

fn visit_variant(&mut self, var: &Variant, g: &'v Generics, item_id: NodeId) {
self.annotate(var.node.data.id(), true, &var.node.attrs, var.span,
|v| visit::walk_variant(v, var, g, item_id), true)
self.annotate(var.node.data.id(), &var.node.attrs, var.span, AnnRequired, |v| {
visit::walk_variant(v, var, g, item_id);
})
}

fn visit_struct_field(&mut self, s: &StructField) {
self.annotate(s.node.id, true, &s.node.attrs, s.span,
|v| visit::walk_struct_field(v, s), !s.node.kind.is_unnamed());
// FIXME: This is temporary, can't use attributes with tuple variant fields until snapshot
let kind = if self.in_enum && s.node.kind.is_unnamed() {
AnnProhibited
} else {
AnnRequired
};
self.annotate(s.node.id, &s.node.attrs, s.span, kind, |v| {
visit::walk_struct_field(v, s);
});
}

fn visit_foreign_item(&mut self, i: &hir::ForeignItem) {
self.annotate(i.id, true, &i.attrs, i.span, |_| {}, true);
self.annotate(i.id, &i.attrs, i.span, AnnRequired, |v| {
visit::walk_foreign_item(v, i);
});
}

fn visit_macro_def(&mut self, md: &'v hir::MacroDef) {
if md.imported_from.is_none() {
self.annotate(md.id, &md.attrs, md.span, AnnRequired, |_| {});
}
}
}

Expand All @@ -243,21 +260,21 @@ impl<'tcx> Index<'tcx> {
index: self,
parent: None,
export_map: export_map,
in_trait_impl: false,
in_enum: false,
};
annotator.annotate(ast::CRATE_NODE_ID, true, &krate.attrs, krate.span,
|v| visit::walk_crate(v, krate), true);
annotator.annotate(ast::CRATE_NODE_ID, &krate.attrs, krate.span, AnnRequired,
|v| visit::walk_crate(v, krate));
}

pub fn new(krate: &Crate) -> Index {
let mut is_staged_api = false;
for attr in &krate.attrs {
if &attr.name()[..] == "staged_api" {
match attr.node.value.node {
ast::MetaWord(_) => {
attr::mark_used(attr);
is_staged_api = true;
}
_ => (/*pass*/)
if attr.name() == "staged_api" {
if let ast::MetaWord(_) = attr.node.value.node {
attr::mark_used(attr);
is_staged_api = true;
break
}
}
}
Expand Down
3 changes: 1 addition & 2 deletions src/librustc_driver/driver.rs
View file
Expand Up @@ -739,7 +739,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
lang_items,
stability::Index::new(krate),
|tcx| {

// passes are timed inside typeck
typeck::check_crate(tcx, trait_map);

Expand All @@ -756,7 +755,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,

// Do not move this check past lint
time(time_passes, "stability index", || {
tcx.stability.borrow_mut().build(tcx, krate, &public_items)
tcx.stability.borrow_mut().build(tcx, krate, &exported_items)
});

time(time_passes,
Expand Down

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