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fix stack overflow by enum and const #36458

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fix stack overflow by enum and const #36458

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118 changes: 66 additions & 52 deletions src/librustc_passes/static_recursion.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ use rustc::dep_graph::DepNode;
use rustc::hir::map as ast_map;
use rustc::session::{CompileResult, Session};
use rustc::hir::def::{Def, CtorKind, DefMap};
use rustc::util::nodemap::NodeMap;
use rustc::util::nodemap::{NodeMap, NodeSet};

use syntax::ast;
use syntax::feature_gate::{GateIssue, emit_feature_err};
Expand All @@ -34,6 +34,7 @@ struct CheckCrateVisitor<'a, 'ast: 'a> {
// each one. If the variant uses the default values (starting from `0`),
// then `None` is stored.
discriminant_map: RefCell<NodeMap<Option<&'ast hir::Expr>>>,
detected_recursive_ids: NodeSet,
}

impl<'a, 'ast: 'a> Visitor<'ast> for CheckCrateVisitor<'a, 'ast> {
Expand Down Expand Up @@ -98,38 +99,43 @@ pub fn check_crate<'ast>(sess: &Session,
def_map: def_map,
ast_map: ast_map,
discriminant_map: RefCell::new(NodeMap()),
detected_recursive_ids: NodeSet(),
};
sess.track_errors(|| {
ast_map.krate().visit_all_items(&mut visitor);
})
}

struct CheckItemRecursionVisitor<'a, 'ast: 'a> {
root_span: &'a Span,
sess: &'a Session,
ast_map: &'a ast_map::Map<'ast>,
def_map: &'a DefMap,
struct CheckItemRecursionVisitor<'a, 'b: 'a, 'ast: 'b> {
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@arielb1 arielb1 Sep 24, 2016 •
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Why 2 lifetimes here? What was the problem with only 'a?

root_span: &'b Span,
sess: &'b Session,
ast_map: &'b ast_map::Map<'ast>,
def_map: &'b DefMap,
discriminant_map: &'a RefCell<NodeMap<Option<&'ast hir::Expr>>>,
idstack: Vec<ast::NodeId>,
detected_recursive_ids: &'a mut NodeSet,
}

impl<'a, 'ast: 'a> CheckItemRecursionVisitor<'a, 'ast> {
fn new(v: &'a CheckCrateVisitor<'a, 'ast>,
span: &'a Span)
-> CheckItemRecursionVisitor<'a, 'ast> {
impl<'a, 'b: 'a, 'ast: 'b> CheckItemRecursionVisitor<'a, 'b, 'ast> {
fn new(v: &'a mut CheckCrateVisitor<'b, 'ast>, span: &'b Span) -> Self {
CheckItemRecursionVisitor {
root_span: span,
sess: v.sess,
ast_map: v.ast_map,
def_map: v.def_map,
discriminant_map: &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 ast_map::NodeItem(item) = self.ast_map.get(x) {
if let hir::ItemStatic(..) = item.node {
Expand All @@ -156,6 +162,7 @@ impl<'a, 'ast: 'a> CheckItemRecursionVisitor<'a, 'ast> {
}
return;
}

self.idstack.push(id);
f(self);
self.idstack.pop();
Expand Down Expand Up @@ -201,9 +208,51 @@ impl<'a, 'ast: 'a> CheckItemRecursionVisitor<'a, 'ast> {
discriminant_map.insert(*id, None);
}
}

fn process_def(&mut self, id: ast::NodeId, span: Span) {
match self.def_map.get(&id).map(|d| d.base_def) {
Some(Def::Static(def_id, _)) |
Some(Def::AssociatedConst(def_id)) |
Some(Def::Const(def_id)) => {
if let Some(node_id) = self.ast_map.as_local_node_id(def_id) {
match self.ast_map.get(node_id) {
ast_map::NodeItem(item) => self.visit_item(item),
ast_map::NodeTraitItem(item) => self.visit_trait_item(item),
ast_map::NodeImplItem(item) => self.visit_impl_item(item),
ast_map::NodeForeignItem(_) => {}
_ => {
span_bug!(span,
"expected item, found {}",
self.ast_map.node_to_string(node_id));
}
}
}
}
// For variants, we only want to check expressions that
// affect the specific variant used, but we need to check
// the whole enum definition to see what expression that
// might be (if any).
Some(Def::VariantCtor(variant_id, CtorKind::Const)) => {
if let Some(variant_id) = self.ast_map.as_local_node_id(variant_id) {
let variant = self.ast_map.expect_variant(variant_id);
let enum_id = self.ast_map.get_parent(variant_id);
let enum_item = self.ast_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!(span,
"`check_static_recursion` found \
non-enum in Def::VariantCtor");
}
}
}
_ => (),
}
}
}

impl<'a, 'ast: 'a> Visitor<'ast> for CheckItemRecursionVisitor<'a, 'ast> {
impl<'a, 'b: 'a, 'ast: 'b> Visitor<'ast> for CheckItemRecursionVisitor<'a, 'b, 'ast> {
fn visit_item(&mut self, it: &'ast hir::Item) {
self.with_item_id_pushed(it.id, |v| intravisit::walk_item(v, it), it.span);
}
Expand Down Expand Up @@ -249,49 +298,14 @@ impl<'a, 'ast: 'a> Visitor<'ast> for CheckItemRecursionVisitor<'a, 'ast> {

fn visit_expr(&mut self, e: &'ast hir::Expr) {
match e.node {
hir::ExprPath(..) => {
match self.def_map.get(&e.id).map(|d| d.base_def) {
Some(Def::Static(def_id, _)) |
Some(Def::AssociatedConst(def_id)) |
Some(Def::Const(def_id)) => {
if let Some(node_id) = self.ast_map.as_local_node_id(def_id) {
match self.ast_map.get(node_id) {
ast_map::NodeItem(item) => self.visit_item(item),
ast_map::NodeTraitItem(item) => self.visit_trait_item(item),
ast_map::NodeImplItem(item) => self.visit_impl_item(item),
ast_map::NodeForeignItem(_) => {}
_ => {
span_bug!(e.span,
"expected item, found {}",
self.ast_map.node_to_string(node_id));
}
}
}
}
// For variants, we only want to check expressions that
// affect the specific variant used, but we need to check
// the whole enum definition to see what expression that
// might be (if any).
Some(Def::VariantCtor(variant_id, CtorKind::Const)) => {
if let Some(variant_id) = self.ast_map.as_local_node_id(variant_id) {
let variant = self.ast_map.expect_variant(variant_id);
let enum_id = self.ast_map.get_parent(variant_id);
let enum_item = self.ast_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!(e.span,
"`check_static_recursion` found \
non-enum in Def::VariantCtor");
}
}
}
_ => (),
}
}
hir::ExprPath(..) => self.process_def(e.id, e.span),
_ => (),
}
intravisit::walk_expr(self, e);
}

fn visit_path(&mut self, path: &'ast hir::Path, id: ast::NodeId) {
self.process_def(id, path.span);
intravisit::walk_path(self, path);
}
}
26 changes: 26 additions & 0 deletions src/test/compile-fail/issue-36163.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
// Copyright 2012 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.

const A: i32 = Foo::B; //~ ERROR E0265
//~^ NOTE recursion not allowed in constant

enum Foo {
B = A, //~ ERROR E0265
//~^ NOTE recursion not allowed in constant
}

enum Bar {
C = Bar::C, //~ ERROR E0265
//~^ NOTE recursion not allowed in constant
}

const D: i32 = A;

fn main() {}