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use rustc::dep_graph::DepNode;
use rustc::hir::map as hir_map;
use rustc::session::{CompileResult, Session};
use rustc::hir::def::{Def, CtorKind};
use rustc::util::nodemap::{NodeMap, NodeSet};
use syntax::ast;
use syntax_pos::Span;
use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
use rustc::hir;
struct CheckCrateVisitor<'a, 'hir: 'a> {
sess: &'a Session,
hir_map: &'a hir_map::Map<'hir>,
discriminant_map: NodeMap<Option<hir::BodyId>>,
detected_recursive_ids: NodeSet,
}
impl<'a, 'hir: 'a> Visitor<'hir> for CheckCrateVisitor<'a, 'hir> {
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'hir> {
NestedVisitorMap::None
}
fn visit_item(&mut self, it: &'hir hir::Item) {
match it.node {
hir::ItemStatic(..) |
hir::ItemConst(..) => {
let mut recursion_visitor = CheckItemRecursionVisitor::new(self);
recursion_visitor.visit_item(it);
}
hir::ItemEnum(ref enum_def, ref generics) => {
for variant in &enum_def.variants {
if let Some(_) = variant.node.disr_expr {
let mut recursion_visitor = CheckItemRecursionVisitor::new(self);
recursion_visitor.populate_enum_discriminants(enum_def);
recursion_visitor.visit_variant(variant, generics, it.id);
}
}
}
_ => {}
}
intravisit::walk_item(self, it)
}
fn visit_trait_item(&mut self, ti: &'hir hir::TraitItem) {
match ti.node {
hir::TraitItemKind::Const(_, ref default) => {
if let Some(_) = *default {
let mut recursion_visitor = CheckItemRecursionVisitor::new(self);
recursion_visitor.visit_trait_item(ti);
}
}
_ => {}
}
intravisit::walk_trait_item(self, ti)
}
fn visit_impl_item(&mut self, ii: &'hir hir::ImplItem) {
match ii.node {
hir::ImplItemKind::Const(..) => {
let mut recursion_visitor = CheckItemRecursionVisitor::new(self);
recursion_visitor.visit_impl_item(ii);
}
_ => {}
}
intravisit::walk_impl_item(self, ii)
}
}
pub fn check_crate<'hir>(sess: &Session, hir_map: &hir_map::Map<'hir>) -> CompileResult {
let _task = hir_map.dep_graph.in_task(DepNode::CheckStaticRecursion);
let mut visitor = CheckCrateVisitor {
sess: sess,
hir_map: hir_map,
discriminant_map: NodeMap(),
detected_recursive_ids: NodeSet(),
};
sess.track_errors(|| {
hir_map.krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
})
}
struct CheckItemRecursionVisitor<'a, 'b: 'a, 'hir: 'b> {
sess: &'b Session,
hir_map: &'b hir_map::Map<'hir>,
discriminant_map: &'a mut NodeMap<Option<hir::BodyId>>,
idstack: Vec<ast::NodeId>,
detected_recursive_ids: &'a mut NodeSet,
}
impl<'a, 'b: 'a, 'hir: 'b> CheckItemRecursionVisitor<'a, 'b, 'hir> {
fn new(v: &'a mut CheckCrateVisitor<'b, 'hir>) -> Self {
CheckItemRecursionVisitor {
sess: v.sess,
hir_map: v.hir_map,
discriminant_map: &mut v.discriminant_map,
idstack: Vec::new(),
detected_recursive_ids: &mut v.detected_recursive_ids,
}
}
fn with_item_id_pushed<F>(&mut self, id: ast::NodeId, f: F, span: Span)
where F: Fn(&mut Self)
{
if self.idstack.iter().any(|&x| x == id) {
if self.detected_recursive_ids.contains(&id) {
return;
}
self.detected_recursive_ids.insert(id);
let any_static = self.idstack.iter().any(|&x| {
if let hir_map::NodeItem(item) = self.hir_map.get(x) {
if let hir::ItemStatic(..) = item.node {
true
} else {
false
}
} else {
false
}
});
if !any_static {
struct_span_err!(self.sess, span, E0265, "recursive constant")
.span_label(span, &format!("recursion not allowed in constant"))
.emit();
}
return;
}
self.idstack.push(id);
f(self);
self.idstack.pop();
}
fn populate_enum_discriminants(&mut self, enum_definition: &'hir hir::EnumDef) {
match enum_definition.variants.first() {
None => {
return;
}
Some(variant) if self.discriminant_map.contains_key(&variant.node.data.id()) => {
return;
}
_ => {}
}
let mut variant_stack: Vec<ast::NodeId> = Vec::new();
for variant in enum_definition.variants.iter().rev() {
variant_stack.push(variant.node.data.id());
if let Some(expr) = variant.node.disr_expr {
for id in &variant_stack {
self.discriminant_map.insert(*id, Some(expr));
}
variant_stack.clear()
}
}
for id in &variant_stack {
self.discriminant_map.insert(*id, None);
}
}
}
impl<'a, 'b: 'a, 'hir: 'b> Visitor<'hir> for CheckItemRecursionVisitor<'a, 'b, 'hir> {
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'hir> {
NestedVisitorMap::OnlyBodies(&self.hir_map)
}
fn visit_item(&mut self, it: &'hir hir::Item) {
self.with_item_id_pushed(it.id, |v| intravisit::walk_item(v, it), it.span);
}
fn visit_enum_def(&mut self,
enum_definition: &'hir hir::EnumDef,
generics: &'hir hir::Generics,
item_id: ast::NodeId,
_: Span) {
self.populate_enum_discriminants(enum_definition);
intravisit::walk_enum_def(self, enum_definition, generics, item_id);
}
fn visit_variant(&mut self,
variant: &'hir hir::Variant,
_: &'hir hir::Generics,
_: ast::NodeId) {
let variant_id = variant.node.data.id();
let maybe_expr = *self.discriminant_map.get(&variant_id).unwrap_or_else(|| {
span_bug!(variant.span,
"`check_static_recursion` attempted to visit \
variant with unknown discriminant")
});
if let Some(expr) = maybe_expr {
let expr = &self.hir_map.body(expr).value;
self.with_item_id_pushed(expr.id, |v| intravisit::walk_expr(v, expr), expr.span);
}
}
fn visit_trait_item(&mut self, ti: &'hir hir::TraitItem) {
self.with_item_id_pushed(ti.id, |v| intravisit::walk_trait_item(v, ti), ti.span);
}
fn visit_impl_item(&mut self, ii: &'hir hir::ImplItem) {
self.with_item_id_pushed(ii.id, |v| intravisit::walk_impl_item(v, ii), ii.span);
}
fn visit_path(&mut self, path: &'hir hir::Path, _: ast::NodeId) {
match path.def {
Def::Static(def_id, _) |
Def::AssociatedConst(def_id) |
Def::Const(def_id) => {
if let Some(node_id) = self.hir_map.as_local_node_id(def_id) {
match self.hir_map.get(node_id) {
hir_map::NodeItem(item) => self.visit_item(item),
hir_map::NodeTraitItem(item) => self.visit_trait_item(item),
hir_map::NodeImplItem(item) => self.visit_impl_item(item),
hir_map::NodeForeignItem(_) => {}
_ => {
span_bug!(path.span,
"expected item, found {}",
self.hir_map.node_to_string(node_id));
}
}
}
}
Def::VariantCtor(variant_id, CtorKind::Const) => {
if let Some(variant_id) = self.hir_map.as_local_node_id(variant_id) {
let variant = self.hir_map.expect_variant(variant_id);
let enum_id = self.hir_map.get_parent(variant_id);
let enum_item = self.hir_map.expect_item(enum_id);
if let hir::ItemEnum(ref enum_def, ref generics) = enum_item.node {
self.populate_enum_discriminants(enum_def);
self.visit_variant(variant, generics, enum_id);
} else {
span_bug!(path.span,
"`check_static_recursion` found \
non-enum in Def::VariantCtor");
}
}
}
_ => (),
}
intravisit::walk_path(self, path);
}
}