-// 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 std::cmp;
-use matches::matches;
-use crate::rustc::hir;
-use crate::rustc::hir::*;
-use crate::rustc::hir::intravisit::FnKind;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
+use crate::utils::{in_macro, is_copy, is_self_ty, snippet, span_lint_and_sugg};
use if_chain::if_chain;
-use crate::rustc::ty::TyKind;
-use crate::rustc::session::config::Config as SessionConfig;
-use crate::rustc_target::spec::abi::Abi;
-use crate::rustc_target::abi::LayoutOf;
-use crate::syntax::ast::NodeId;
-use crate::syntax_pos::Span;
-use crate::utils::{in_macro, is_copy, is_self, span_lint_and_sugg, snippet};
-
-/// **What it does:** Checks for functions taking arguments by reference, where
-/// the argument type is `Copy` and small enough to be more efficient to always
-/// pass by value.
-///
-/// **Why is this bad?** In many calling conventions instances of structs will
-/// be passed through registers if they fit into two or less general purpose
-/// registers.
-///
-/// **Known problems:** This lint is target register size dependent, it is
-/// limited to 32-bit to try and reduce portability problems between 32 and
-/// 64-bit, but if you are compiling for 8 or 16-bit targets then the limit
-/// will be different.
-///
-/// The configuration option `trivial_copy_size_limit` can be set to override
-/// this limit for a project.
-///
-/// This lint attempts to allow passing arguments by reference if a reference
-/// to that argument is returned. This is implemented by comparing the lifetime
-/// of the argument and return value for equality. However, this can cause
-/// false positives in cases involving multiple lifetimes that are bounded by
-/// each other.
-///
-/// **Example:**
-/// ```rust
-/// fn foo(v: &u32) {
-/// assert_eq!(v, 42);
-/// }
-/// // should be
-/// fn foo(v: u32) {
-/// assert_eq!(v, 42);
-/// }
-/// ```
+use matches::matches;
+use rustc::hir;
+use rustc::hir::intravisit::FnKind;
+use rustc::hir::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::session::config::Config as SessionConfig;
+use rustc::ty::{self, FnSig};
+use rustc::{declare_tool_lint, lint_array};
+use rustc_errors::Applicability;
+use rustc_target::abi::LayoutOf;
+use rustc_target::spec::abi::Abi;
+use syntax_pos::Span;
+
declare_clippy_lint! {
+ /// **What it does:** Checks for functions taking arguments by reference, where
+ /// the argument type is `Copy` and small enough to be more efficient to always
+ /// pass by value.
+ ///
+ /// **Why is this bad?** In many calling conventions instances of structs will
+ /// be passed through registers if they fit into two or less general purpose
+ /// registers.
+ ///
+ /// **Known problems:** This lint is target register size dependent, it is
+ /// limited to 32-bit to try and reduce portability problems between 32 and
+ /// 64-bit, but if you are compiling for 8 or 16-bit targets then the limit
+ /// will be different.
+ ///
+ /// The configuration option `trivial_copy_size_limit` can be set to override
+ /// this limit for a project.
+ ///
+ /// This lint attempts to allow passing arguments by reference if a reference
+ /// to that argument is returned. This is implemented by comparing the lifetime
+ /// of the argument and return value for equality. However, this can cause
+ /// false positives in cases involving multiple lifetimes that are bounded by
+ /// each other.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// fn foo(v: &u32) {
+ /// assert_eq!(v, 42);
+ /// }
+ /// // should be
+ /// fn foo(v: u32) {
+ /// assert_eq!(v, 42);
+ /// }
+ /// ```
pub TRIVIALLY_COPY_PASS_BY_REF,
perf,
"functions taking small copyable arguments by reference"
limit: u64,
}
-impl TriviallyCopyPassByRef {
+impl<'a, 'tcx> TriviallyCopyPassByRef {
pub fn new(limit: Option<u64>, target: &SessionConfig) -> Self {
let limit = limit.unwrap_or_else(|| {
let bit_width = target.usize_ty.bit_width().expect("usize should have a width") as u64;
});
Self { limit }
}
+
+ fn check_trait_method(&mut self, cx: &LateContext<'_, 'tcx>, item: &TraitItemRef) {
+ let method_def_id = cx.tcx.hir().local_def_id_from_hir_id(item.id.hir_id);
+ let method_sig = cx.tcx.fn_sig(method_def_id);
+ let method_sig = cx.tcx.erase_late_bound_regions(&method_sig);
+
+ let decl = match cx.tcx.hir().fn_decl_by_hir_id(item.id.hir_id) {
+ Some(b) => b,
+ None => return,
+ };
+
+ self.check_poly_fn(cx, &decl, &method_sig, None);
+ }
+
+ fn check_poly_fn(&mut self, cx: &LateContext<'_, 'tcx>, decl: &FnDecl, sig: &FnSig<'tcx>, span: Option<Span>) {
+ // Use lifetimes to determine if we're returning a reference to the
+ // argument. In that case we can't switch to pass-by-value as the
+ // argument will not live long enough.
+ let output_lts = match sig.output().sty {
+ ty::Ref(output_lt, _, _) => vec![output_lt],
+ ty::Adt(_, substs) => substs.regions().collect(),
+ _ => vec![],
+ };
+
+ for (input, &ty) in decl.inputs.iter().zip(sig.inputs()) {
+ // All spans generated from a proc-macro invocation are the same...
+ match span {
+ Some(s) if s == input.span => return,
+ _ => (),
+ }
+
+ if_chain! {
+ if let ty::Ref(input_lt, ty, Mutability::MutImmutable) = ty.sty;
+ if !output_lts.contains(&input_lt);
+ if is_copy(cx, ty);
+ if let Some(size) = cx.layout_of(ty).ok().map(|l| l.size.bytes());
+ if size <= self.limit;
+ if let hir::TyKind::Rptr(_, MutTy { ty: ref decl_ty, .. }) = input.node;
+ then {
+ let value_type = if is_self_ty(decl_ty) {
+ "self".into()
+ } else {
+ snippet(cx, decl_ty.span, "_").into()
+ };
+ span_lint_and_sugg(
+ cx,
+ TRIVIALLY_COPY_PASS_BY_REF,
+ input.span,
+ "this argument is passed by reference, but would be more efficient if passed by value",
+ "consider passing by value instead",
+ value_type,
+ Applicability::Unspecified,
+ );
+ }
+ }
+ }
+ }
+
+ fn check_trait_items(&mut self, cx: &LateContext<'_, '_>, trait_items: &[TraitItemRef]) {
+ for item in trait_items {
+ if let AssociatedItemKind::Method { .. } = item.kind {
+ self.check_trait_method(cx, item);
+ }
+ }
+ }
}
impl LintPass for TriviallyCopyPassByRef {
fn get_lints(&self) -> LintArray {
lint_array![TRIVIALLY_COPY_PASS_BY_REF]
}
+
+ fn name(&self) -> &'static str {
+ "TrivallyCopyPassByRef"
+ }
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TriviallyCopyPassByRef {
+ fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
+ if in_macro(item.span) {
+ return;
+ }
+ if let ItemKind::Trait(_, _, _, _, ref trait_items) = item.node {
+ self.check_trait_items(cx, trait_items);
+ }
+ }
+
fn check_fn(
&mut self,
cx: &LateContext<'a, 'tcx>,
kind: FnKind<'tcx>,
decl: &'tcx FnDecl,
- body: &'tcx Body,
+ _body: &'tcx Body,
span: Span,
- node_id: NodeId,
+ hir_id: HirId,
) {
if in_macro(span) {
return;
return;
}
for a in attrs {
- if a.meta_item_list().is_some() && a.name() == "proc_macro_derive" {
+ if a.meta_item_list().is_some() && a.check_name("proc_macro_derive") {
return;
}
}
}
// Exclude non-inherent impls
- if let Some(Node::Item(item)) = cx.tcx.hir.find(cx.tcx.hir.get_parent_node(node_id)) {
+ if let Some(Node::Item(item)) = cx
+ .tcx
+ .hir()
+ .find_by_hir_id(cx.tcx.hir().get_parent_node_by_hir_id(hir_id))
+ {
if matches!(item.node, ItemKind::Impl(_, _, _, _, Some(_), _, _) |
ItemKind::Trait(..))
{
}
}
- let fn_def_id = cx.tcx.hir.local_def_id(node_id);
+ let fn_def_id = cx.tcx.hir().local_def_id_from_hir_id(hir_id);
let fn_sig = cx.tcx.fn_sig(fn_def_id);
let fn_sig = cx.tcx.erase_late_bound_regions(&fn_sig);
- // Use lifetimes to determine if we're returning a reference to the
- // argument. In that case we can't switch to pass-by-value as the
- // argument will not live long enough.
- let output_lts = match fn_sig.output().sty {
- TyKind::Ref(output_lt, _, _) => vec![output_lt],
- TyKind::Adt(_, substs) => substs.regions().collect(),
- _ => vec![],
- };
-
- for ((input, &ty), arg) in decl.inputs.iter().zip(fn_sig.inputs()).zip(&body.arguments) {
- // All spans generated from a proc-macro invocation are the same...
- if span == input.span {
- return;
- }
-
- if_chain! {
- if let TyKind::Ref(input_lt, ty, Mutability::MutImmutable) = ty.sty;
- if !output_lts.contains(&input_lt);
- if is_copy(cx, ty);
- if let Some(size) = cx.layout_of(ty).ok().map(|l| l.size.bytes());
- if size <= self.limit;
- if let hir::TyKind::Rptr(_, MutTy { ty: ref decl_ty, .. }) = input.node;
- then {
- let value_type = if is_self(arg) {
- "self".into()
- } else {
- snippet(cx, decl_ty.span, "_").into()
- };
- span_lint_and_sugg(
- cx,
- TRIVIALLY_COPY_PASS_BY_REF,
- input.span,
- "this argument is passed by reference, but would be more efficient if passed by value",
- "consider passing by value instead",
- value_type);
- }
- }
- }
+ self.check_poly_fn(cx, decl, &fn_sig, Some(span));
}
}
projects / rust.git / blobdiff