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// Copyright 2012-2015 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.
//
use rustc::hir;
use rustc::lint::*;
use syntax::ast;
use syntax::codemap::Span;
/// **What it does:** it lints if an exported function, method, trait method with default impl,
/// or trait method impl is not `#[inline]`.
///
/// **Why is this bad?** In general, it is not. Functions can be inlined across
/// crates when that's profitable as long as any form of LTO is used. When LTO is disabled,
/// functions that are not `#[inline]` cannot be inlined across crates. Certain types of crates
/// might intend for most of the methods in their public API to be able to be inlined across
/// crates even when LTO is disabled. For these types of crates, enabling this lint might make sense.
/// It allows the crate to require all exported methods to be `#[inline]` by default, and then opt
/// out for specific methods where this might not make sense.
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// pub fn foo() {} // missing #[inline]
/// fn ok() {} // ok
/// #[inline] pub fn bar() {} // ok
/// #[inline(always)] pub fn baz() {} // ok
///
/// pub trait Bar {
/// fn bar(); // ok
/// fn def_bar() {} // missing #[inline]
/// }
///
/// struct Baz;
/// impl Baz {
/// fn priv() {} // ok
/// }
///
/// impl Bar for Baz {
/// fn bar() {} // ok - Baz is not exported
/// }
///
/// pub struct PubBaz;
/// impl PubBaz {
/// fn priv() {} // ok
/// pub not_ptriv() {} // missing #[inline]
/// }
///
/// impl Bar for PubBaz {
/// fn bar() {} // missing #[inline]
/// fn def_bar() {} // missing #[inline]
/// }
/// ```
declare_clippy_lint! {
pub MISSING_INLINE_IN_PUBLIC_ITEMS,
restriction,
"detects missing #[inline] attribute for public callables (functions, trait methods, methods...)"
}
pub struct MissingInline;
fn check_missing_inline_attrs(cx: &LateContext,
attrs: &[ast::Attribute], sp: Span, desc: &'static str) {
let has_inline = attrs
.iter()
.any(|a| a.name() == "inline" );
if !has_inline {
cx.span_lint(
MISSING_INLINE_IN_PUBLIC_ITEMS,
sp,
&format!("missing `#[inline]` for {}", desc),
);
}
}
fn is_executable<'a, 'tcx>(cx: &LateContext<'a, 'tcx>) -> bool {
use rustc::session::config::CrateType;
cx.tcx.sess.crate_types.get().iter().any(|t: &CrateType| {
match t {
CrateType::CrateTypeExecutable => true,
_ => false,
}
})
}
impl LintPass for MissingInline {
fn get_lints(&self) -> LintArray {
lint_array![MISSING_INLINE_IN_PUBLIC_ITEMS]
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingInline {
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, it: &'tcx hir::Item) {
if is_executable(cx) {
return;
}
if !cx.access_levels.is_exported(it.id) {
return;
}
match it.node {
hir::ItemFn(..) => {
let desc = "a function";
check_missing_inline_attrs(cx, &it.attrs, it.span, desc);
},
hir::ItemTrait(ref _is_auto, ref _unsafe, ref _generics,
ref _bounds, ref trait_items) => {
// note: we need to check if the trait is exported so we can't use
// `LateLintPass::check_trait_item` here.
for tit in trait_items {
let tit_ = cx.tcx.hir.trait_item(tit.id);
match tit_.node {
hir::TraitItemKind::Const(..) |
hir::TraitItemKind::Type(..) => {},
hir::TraitItemKind::Method(..) => {
if tit.defaultness.has_value() {
// trait method with default body needs inline in case
// an impl is not provided
let desc = "a default trait method";
let item = cx.tcx.hir.expect_trait_item(tit.id.node_id);
check_missing_inline_attrs(cx, &item.attrs,
item.span, desc);
}
},
}
}
}
hir::ItemConst(..) |
hir::ItemEnum(..) |
hir::ItemMod(..) |
hir::ItemStatic(..) |
hir::ItemStruct(..) |
hir::ItemTraitAlias(..) |
hir::ItemGlobalAsm(..) |
hir::ItemTy(..) |
hir::ItemUnion(..) |
hir::ItemExistential(..) |
hir::ItemExternCrate(..) |
hir::ItemForeignMod(..) |
hir::ItemImpl(..) |
hir::ItemUse(..) => {},
};
}
fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx hir::ImplItem) {
use rustc::ty::{TraitContainer, ImplContainer};
if is_executable(cx) {
return;
}
// If the item being implemented is not exported, then we don't need #[inline]
if !cx.access_levels.is_exported(impl_item.id) {
return;
}
let desc = match impl_item.node {
hir::ImplItemKind::Method(..) => "a method",
hir::ImplItemKind::Const(..) |
hir::ImplItemKind::Type(_) => return,
};
let def_id = cx.tcx.hir.local_def_id(impl_item.id);
match cx.tcx.associated_item(def_id).container {
TraitContainer(cid) => {
if let Some(n) = cx.tcx.hir.as_local_node_id(cid) {
if !cx.access_levels.is_exported(n) {
// If a trait is being implemented for an item, and the
// trait is not exported, we don't need #[inline]
return;
}
}
},
ImplContainer(cid) => {
if cx.tcx.impl_trait_ref(cid).is_some() {
let trait_ref = cx.tcx.impl_trait_ref(cid).unwrap();
if let Some(n) = cx.tcx.hir.as_local_node_id(trait_ref.def_id) {
if !cx.access_levels.is_exported(n) {
// If a trait is being implemented for an item, and the
// trait is not exported, we don't need #[inline]
return;
}
}
}
},
}
check_missing_inline_attrs(cx, &impl_item.attrs, impl_item.span, desc);
}
}