-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// 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 crate::rustc::hir::*;
-use crate::rustc::hir::intravisit as visit;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::rustc::middle::expr_use_visitor::*;
-use crate::rustc::middle::mem_categorization::{cmt_, Categorization};
-use crate::rustc::ty::{self, Ty};
-use crate::rustc::ty::layout::LayoutOf;
-use crate::rustc::util::nodemap::NodeSet;
-use crate::syntax::ast::NodeId;
-use crate::syntax::source_map::Span;
+use rustc::hir::intravisit as visit;
+use rustc::hir::{self, *};
+use rustc::impl_lint_pass;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::ty::layout::LayoutOf;
+use rustc::ty::{self, Ty};
+use rustc::util::nodemap::HirIdSet;
+use rustc_session::declare_tool_lint;
+use rustc_typeck::expr_use_visitor::*;
+use syntax::source_map::Span;
+
use crate::utils::span_lint;
-pub struct Pass {
+#[derive(Copy, Clone)]
+pub struct BoxedLocal {
pub too_large_for_stack: u64,
}
-/// **What it does:** Checks for usage of `Box<T>` where an unboxed `T` would
-/// work fine.
-///
-/// **Why is this bad?** This is an unnecessary allocation, and bad for
-/// performance. It is only necessary to allocate if you wish to move the box
-/// into something.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// fn main() {
-/// let x = Box::new(1);
-/// foo(*x);
-/// println!("{}", *x);
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `Box<T>` where an unboxed `T` would
+ /// work fine.
+ ///
+ /// **Why is this bad?** This is an unnecessary allocation, and bad for
+ /// performance. It is only necessary to allocate if you wish to move the box
+ /// into something.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # fn foo(bar: usize) {}
+ /// let x = Box::new(1);
+ /// foo(*x);
+ /// println!("{}", *x);
+ /// ```
pub BOXED_LOCAL,
perf,
"using `Box<T>` where unnecessary"
ty.is_box() && !ty.boxed_ty().is_trait()
}
-struct EscapeDelegate<'a, 'tcx: 'a> {
+struct EscapeDelegate<'a, 'tcx> {
cx: &'a LateContext<'a, 'tcx>,
- set: NodeSet,
+ set: HirIdSet,
too_large_for_stack: u64,
}
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(BOXED_LOCAL)
- }
-}
+impl_lint_pass!(BoxedLocal => [BOXED_LOCAL]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BoxedLocal {
fn check_fn(
&mut self,
cx: &LateContext<'a, 'tcx>,
_: visit::FnKind<'tcx>,
_: &'tcx FnDecl,
- body: &'tcx Body,
+ body: &'tcx Body<'_>,
_: Span,
- node_id: NodeId,
+ hir_id: HirId,
) {
- let fn_def_id = cx.tcx.hir.local_def_id(node_id);
+ // If the method is an impl for a trait, don't warn.
+ let parent_id = cx.tcx.hir().get_parent_item(hir_id);
+ let parent_node = cx.tcx.hir().find(parent_id);
+
+ if let Some(Node::Item(item)) = parent_node {
+ if let ItemKind::Impl(_, _, _, _, Some(..), _, _) = item.kind {
+ return;
+ }
+ }
+
let mut v = EscapeDelegate {
cx,
- set: NodeSet(),
+ set: HirIdSet::default(),
too_large_for_stack: self.too_large_for_stack,
};
- let region_scope_tree = &cx.tcx.region_scope_tree(fn_def_id);
- ExprUseVisitor::new(&mut v, cx.tcx, cx.param_env, region_scope_tree, cx.tables, None).consume_body(body);
+ let fn_def_id = cx.tcx.hir().local_def_id(hir_id);
+ cx.tcx.infer_ctxt().enter(|infcx| {
+ ExprUseVisitor::new(&mut v, &infcx, fn_def_id, cx.param_env, cx.tables).consume_body(body);
+ });
for node in v.set {
span_lint(
cx,
BOXED_LOCAL,
- cx.tcx.hir.span(node),
+ cx.tcx.hir().span(node),
"local variable doesn't need to be boxed here",
);
}
}
}
-impl<'a, 'tcx> Delegate<'tcx> for EscapeDelegate<'a, 'tcx> {
- fn consume(&mut self, _: NodeId, _: Span, cmt: &cmt_<'tcx>, mode: ConsumeMode) {
- if let Categorization::Local(lid) = cmt.cat {
- if let Move(DirectRefMove) = mode {
- // moved out or in. clearly can't be localized
- self.set.remove(&lid);
- }
- }
+// TODO: Replace with Map::is_argument(..) when it's fixed
+fn is_argument(map: &hir::map::Map<'_>, id: HirId) -> bool {
+ match map.find(id) {
+ Some(Node::Binding(_)) => (),
+ _ => return false,
}
- fn matched_pat(&mut self, _: &Pat, _: &cmt_<'tcx>, _: MatchMode) {}
- fn consume_pat(&mut self, consume_pat: &Pat, cmt: &cmt_<'tcx>, _: ConsumeMode) {
- let map = &self.cx.tcx.hir;
- if map.is_argument(consume_pat.id) {
- // Skip closure arguments
- if let Some(Node::Expr(..)) = map.find(map.get_parent_node(consume_pat.id)) {
- return;
- }
- if is_non_trait_box(cmt.ty) && !self.is_large_box(cmt.ty) {
- self.set.insert(consume_pat.id);
- }
- return;
- }
- if let Categorization::Rvalue(..) = cmt.cat {
- let id = map.hir_to_node_id(cmt.hir_id);
- if let Some(Node::Stmt(st)) = map.find(map.get_parent_node(id)) {
- if let StmtKind::Decl(ref decl, _) = st.node {
- if let DeclKind::Local(ref loc) = decl.node {
- if let Some(ref ex) = loc.init {
- if let ExprKind::Box(..) = ex.node {
- if is_non_trait_box(cmt.ty) && !self.is_large_box(cmt.ty) {
- // let x = box (...)
- self.set.insert(consume_pat.id);
- }
- // TODO Box::new
- // TODO vec![]
- // TODO "foo".to_owned() and friends
- }
- }
+
+ match map.find(map.get_parent_node(id)) {
+ Some(Node::Param(_)) => true,
+ _ => false,
+ }
+}
+
+impl<'a, 'tcx> Delegate<'tcx> for EscapeDelegate<'a, 'tcx> {
+ fn consume(&mut self, cmt: &Place<'tcx>, mode: ConsumeMode) {
+ if cmt.projections.is_empty() {
+ if let PlaceBase::Local(lid) = cmt.base {
+ if let ConsumeMode::Move = mode {
+ // moved out or in. clearly can't be localized
+ self.set.remove(&lid);
+ }
+ let map = &self.cx.tcx.hir();
+ if let Some(Node::Binding(_)) = map.find(cmt.hir_id) {
+ if self.set.contains(&lid) {
+ // let y = x where x is known
+ // remove x, insert y
+ self.set.insert(cmt.hir_id);
+ self.set.remove(&lid);
}
}
}
}
- if let Categorization::Local(lid) = cmt.cat {
- if self.set.contains(&lid) {
- // let y = x where x is known
- // remove x, insert y
- self.set.insert(consume_pat.id);
+ }
+
+ fn borrow(&mut self, cmt: &Place<'tcx>, _: ty::BorrowKind) {
+ if cmt.projections.is_empty() {
+ if let PlaceBase::Local(lid) = cmt.base {
self.set.remove(&lid);
}
}
}
- fn borrow(&mut self, _: NodeId, _: Span, cmt: &cmt_<'tcx>, _: ty::Region<'_>, _: ty::BorrowKind, loan_cause: LoanCause) {
- if let Categorization::Local(lid) = cmt.cat {
- match loan_cause {
- // x.foo()
- // Used without autodereffing (i.e. x.clone())
- LoanCause::AutoRef |
-
- // &x
- // foo(&x) where no extra autoreffing is happening
- LoanCause::AddrOf |
-
- // `match x` can move
- LoanCause::MatchDiscriminant => {
- self.set.remove(&lid);
+
+ fn mutate(&mut self, cmt: &Place<'tcx>) {
+ if cmt.projections.is_empty() {
+ let map = &self.cx.tcx.hir();
+ if is_argument(map, cmt.hir_id) {
+ // Skip closure arguments
+ let parent_id = map.get_parent_node(cmt.hir_id);
+ if let Some(Node::Expr(..)) = map.find(map.get_parent_node(parent_id)) {
+ return;
}
- // do nothing for matches, etc. These can't escape
- _ => {}
+ if is_non_trait_box(cmt.ty) && !self.is_large_box(cmt.ty) {
+ self.set.insert(cmt.hir_id);
+ }
+ return;
}
}
}
- fn decl_without_init(&mut self, _: NodeId, _: Span) {}
- fn mutate(&mut self, _: NodeId, _: Span, _: &cmt_<'tcx>, _: MutateMode) {}
}
impl<'a, 'tcx> EscapeDelegate<'a, 'tcx> {
fn is_large_box(&self, ty: Ty<'tcx>) -> bool {
- // Large types need to be boxed to avoid stack
- // overflows.
+ // Large types need to be boxed to avoid stack overflows.
if ty.is_box() {
- self.cx.layout_of(ty.boxed_ty()).ok().map_or(0, |l| l.size.bytes()) > self.too_large_for_stack
+ self.cx.layout_of(ty.boxed_ty()).map_or(0, |l| l.size.bytes()) > self.too_large_for_stack
} else {
false
}
projects / rust.git / blobdiff