use rustc::hir::*;
use rustc::hir::intravisit as visit;
use rustc::hir::map::Node::{NodeExpr, NodeStmt};
-use rustc::infer::InferCtxt;
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
use rustc::middle::expr_use_visitor::*;
-use rustc::middle::mem_categorization::{cmt, Categorization};
-use rustc::ty::adjustment::AutoAdjustment;
-use rustc::ty;
-use rustc::ty::layout::TargetDataLayout;
+use rustc::middle::mem_categorization::{cmt_, Categorization};
+use rustc::ty::{self, Ty};
+use rustc::ty::layout::LayoutOf;
use rustc::util::nodemap::NodeSet;
use syntax::ast::NodeId;
use syntax::codemap::Span;
-use utils::span_lint;
+use crate::utils::span_lint;
pub struct Pass {
pub too_large_for_stack: u64,
}
-/// **What it does:** This lint checks for usage of `Box<T>` where an unboxed `T` would work fine.
+/// **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.
+/// **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
+/// **Known problems:** None.
///
/// **Example:**
-///
/// ```rust
/// fn main() {
/// let x = Box::new(1);
/// println!("{}", *x);
/// }
/// ```
-declare_lint! {
- pub BOXED_LOCAL, Warn, "using `Box<T>` where unnecessary"
+declare_clippy_lint! {
+ pub BOXED_LOCAL,
+ perf,
+ "using `Box<T>` where unnecessary"
}
-fn is_non_trait_box(ty: ty::Ty) -> bool {
- match ty.sty {
- ty::TyBox(inner) => !inner.is_trait(),
- _ => false,
- }
+fn is_non_trait_box(ty: Ty) -> bool {
+ ty.is_box() && !ty.boxed_ty().is_trait()
}
-struct EscapeDelegate<'a, 'tcx: 'a+'gcx, 'gcx: 'a> {
- tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
+struct EscapeDelegate<'a, 'tcx: 'a> {
+ cx: &'a LateContext<'a, 'tcx>,
set: NodeSet,
- infcx: &'a InferCtxt<'a, 'gcx, 'gcx>,
- target: TargetDataLayout,
too_large_for_stack: u64,
}
}
}
-impl LateLintPass for Pass {
- fn check_fn(&mut self, cx: &LateContext, _: visit::FnKind, decl: &FnDecl, body: &Block, _: Span, id: NodeId) {
- let param_env = ty::ParameterEnvironment::for_item(cx.tcx, id);
-
- let infcx = cx.tcx.borrowck_fake_infer_ctxt(param_env);
-
- // we store the infcx because it is expensive to recreate
- // the context each time.
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+ fn check_fn(
+ &mut self,
+ cx: &LateContext<'a, 'tcx>,
+ _: visit::FnKind<'tcx>,
+ _: &'tcx FnDecl,
+ body: &'tcx Body,
+ _: Span,
+ node_id: NodeId,
+ ) {
+ let fn_def_id = cx.tcx.hir.local_def_id(node_id);
let mut v = EscapeDelegate {
- tcx: cx.tcx,
+ cx,
set: NodeSet(),
- infcx: &infcx,
- target: TargetDataLayout::parse(cx.sess()),
too_large_for_stack: self.too_large_for_stack,
};
- {
- let mut vis = ExprUseVisitor::new(&mut v, &infcx);
- vis.walk_fn(decl, body);
- }
+ 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);
for node in v.set {
- span_lint(cx,
- BOXED_LOCAL,
- cx.tcx.map.span(node),
- "local variable doesn't need to be boxed here");
+ span_lint(
+ cx,
+ BOXED_LOCAL,
+ cx.tcx.hir.span(node),
+ "local variable doesn't need to be boxed here",
+ );
}
}
}
-impl<'a, 'tcx: 'a+'gcx, 'gcx: 'a> Delegate<'tcx> for EscapeDelegate<'a, 'tcx, 'gcx> {
- fn consume(&mut self, _: NodeId, _: Span, cmt: cmt<'tcx>, mode: ConsumeMode) {
+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 self.set.contains(&lid) {
- if let Move(DirectRefMove) = mode {
- // moved out or in. clearly can't be localized
- self.set.remove(&lid);
- }
+ if let Move(DirectRefMove) = mode {
+ // moved out or in. clearly can't be localized
+ self.set.remove(&lid);
}
}
}
- fn matched_pat(&mut self, _: &Pat, _: cmt<'tcx>, _: MatchMode) {}
- fn consume_pat(&mut self, consume_pat: &Pat, cmt: cmt<'tcx>, _: ConsumeMode) {
- let map = &self.tcx.map;
+ 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(NodeExpr(..)) = map.find(map.get_parent_node(consume_pat.id)) {
return;
}
if let Categorization::Rvalue(..) = cmt.cat {
- if let Some(NodeStmt(st)) = map.find(map.get_parent_node(cmt.id)) {
- if let StmtDecl(ref decl, _) = st.node {
- if let DeclLocal(ref loc) = decl.node {
+ let id = map.hir_to_node_id(cmt.hir_id);
+ if let Some(NodeStmt(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 ExprBox(..) = ex.node {
+ 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);
self.set.remove(&lid);
}
}
-
}
- fn borrow(&mut self, borrow_id: NodeId, _: Span, cmt: cmt<'tcx>, _: ty::Region, _: ty::BorrowKind,
- loan_cause: LoanCause) {
-
+ fn borrow(&mut self, _: NodeId, _: Span, cmt: &cmt_<'tcx>, _: ty::Region, _: ty::BorrowKind, loan_cause: LoanCause) {
if let Categorization::Local(lid) = cmt.cat {
- if self.set.contains(&lid) {
- if let Some(&AutoAdjustment::AdjustDerefRef(adj)) = self.tcx
- .tables
- .borrow()
- .adjustments
- .get(&borrow_id) {
- if LoanCause::AutoRef == loan_cause {
- // x.foo()
- if adj.autoderefs == 0 {
- self.set.remove(&lid); // Used without autodereffing (i.e. x.clone())
- }
- } else {
- span_bug!(cmt.span, "Unknown adjusted AutoRef");
- }
- } else if LoanCause::AddrOf == loan_cause {
- // &x
- if let Some(&AutoAdjustment::AdjustDerefRef(adj)) = self.tcx
- .tables
- .borrow()
- .adjustments
- .get(&self.tcx
- .map
- .get_parent_node(borrow_id)) {
- if adj.autoderefs <= 1 {
- // foo(&x) where no extra autoreffing is happening
- self.set.remove(&lid);
- }
- }
+ 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 |
- } else if LoanCause::MatchDiscriminant == loan_cause {
- self.set.remove(&lid); // `match x` can move
+ // `match x` can move
+ LoanCause::MatchDiscriminant => {
+ self.set.remove(&lid);
}
+
// do nothing for matches, etc. These can't escape
+ _ => {}
}
}
}
fn decl_without_init(&mut self, _: NodeId, _: Span) {}
- fn mutate(&mut self, _: NodeId, _: Span, _: cmt<'tcx>, _: MutateMode) {}
+ fn mutate(&mut self, _: NodeId, _: Span, _: &cmt_<'tcx>, _: MutateMode) {}
}
-impl<'a, 'tcx: 'a+'gcx, 'gcx: 'a> EscapeDelegate<'a, 'tcx, 'gcx> {
- fn is_large_box(&self, ty: ty::Ty<'gcx>) -> bool {
+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.
- match ty.sty {
- ty::TyBox(inner) => {
- if let Ok(layout) = inner.layout(self.infcx) {
- let size = layout.size(&self.target);
- size.bytes() > self.too_large_for_stack
- } else {
- false
- }
- },
- _ => false,
+ if ty.is_box() {
+ self.cx.layout_of(ty.boxed_ty()).ok().map_or(0, |l| l.size.bytes()) > self.too_large_for_stack
+ } else {
+ false
}
}
}
projects / rust.git / blobdiff