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| 1 | +// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT |
| 2 | +// file at the top-level directory of this distribution and at |
| 3 | +// http://rust-lang.org/COPYRIGHT. |
| 4 | +// |
| 5 | +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 7 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| 8 | +// option. This file may not be copied, modified, or distributed |
| 9 | +// except according to those terms. |
| 10 | +// |
| 11 | + |
| 12 | +use rustc::hir; |
| 13 | +use rustc::lint::*; |
| 14 | +use syntax::ast; |
| 15 | +use syntax::codemap::Span; |
| 16 | + |
| 17 | +/// **What it does:** it lints if an exported function, method, trait method with default impl, |
| 18 | +/// or trait method impl is not `#[inline]`. |
| 19 | +/// |
| 20 | +/// **Why is this bad?** In general, it is not. Functions can be inlined across |
| 21 | +/// crates when that's profitable as long as any form of LTO is used. When LTO is disabled, |
| 22 | +/// functions that are not `#[inline]` cannot be inlined across crates. Certain types of crates |
| 23 | +/// might intend for most of the methods in their public API to be able to be inlined across |
| 24 | +/// crates even when LTO is disabled. For these types of crates, enabling this lint might make sense. |
| 25 | +/// It allows the crate to require all exported methods to be `#[inline]` by default, and then opt |
| 26 | +/// out for specific methods where this might not make sense. |
| 27 | +/// |
| 28 | +/// **Known problems:** None. |
| 29 | +/// |
| 30 | +/// **Example:** |
| 31 | +/// ```rust |
| 32 | +/// pub fn foo() {} // missing #[inline] |
| 33 | +/// fn ok() {} // ok |
| 34 | +/// #[inline] pub fn bar() {} // ok |
| 35 | +/// #[inline(always)] pub fn baz() {} // ok |
| 36 | +/// |
| 37 | +/// pub trait Bar { |
| 38 | +/// fn bar(); // ok |
| 39 | +/// fn def_bar() {} // missing #[inline] |
| 40 | +/// } |
| 41 | +/// |
| 42 | +/// struct Baz; |
| 43 | +/// impl Baz { |
| 44 | +/// fn priv() {} // ok |
| 45 | +/// } |
| 46 | +/// |
| 47 | +/// impl Bar for Baz { |
| 48 | +/// fn bar() {} // ok - Baz is not exported |
| 49 | +/// } |
| 50 | +/// |
| 51 | +/// pub struct PubBaz; |
| 52 | +/// impl PubBaz { |
| 53 | +/// fn priv() {} // ok |
| 54 | +/// pub not_ptriv() {} // missing #[inline] |
| 55 | +/// } |
| 56 | +/// |
| 57 | +/// impl Bar for PubBaz { |
| 58 | +/// fn bar() {} // missing #[inline] |
| 59 | +/// fn def_bar() {} // missing #[inline] |
| 60 | +/// } |
| 61 | +/// ``` |
| 62 | +declare_clippy_lint! { |
| 63 | + pub MISSING_INLINE_IN_PUBLIC_ITEMS, |
| 64 | + restriction, |
| 65 | + "detects missing #[inline] attribute for public callables (functions, trait methods, methods...)" |
| 66 | +} |
| 67 | + |
| 68 | +pub struct MissingInline; |
| 69 | + |
| 70 | +fn check_missing_inline_attrs(cx: &LateContext, |
| 71 | + attrs: &[ast::Attribute], sp: Span, desc: &'static str) { |
| 72 | + let has_inline = attrs |
| 73 | + .iter() |
| 74 | + .any(|a| a.name() == "inline" ); |
| 75 | + if !has_inline { |
| 76 | + cx.span_lint( |
| 77 | + MISSING_INLINE_IN_PUBLIC_ITEMS, |
| 78 | + sp, |
| 79 | + &format!("missing `#[inline]` for {}", desc), |
| 80 | + ); |
| 81 | + } |
| 82 | +} |
| 83 | + |
| 84 | +fn is_executable<'a, 'tcx>(cx: &LateContext<'a, 'tcx>) -> bool { |
| 85 | + use rustc::session::config::CrateType; |
| 86 | + |
| 87 | + cx.tcx.sess.crate_types.get().iter().any(|t: &CrateType| { |
| 88 | + match t { |
| 89 | + CrateType::CrateTypeExecutable => true, |
| 90 | + _ => false, |
| 91 | + } |
| 92 | + }) |
| 93 | +} |
| 94 | + |
| 95 | +impl LintPass for MissingInline { |
| 96 | + fn get_lints(&self) -> LintArray { |
| 97 | + lint_array![MISSING_INLINE_IN_PUBLIC_ITEMS] |
| 98 | + } |
| 99 | +} |
| 100 | + |
| 101 | +impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingInline { |
| 102 | + fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, it: &'tcx hir::Item) { |
| 103 | + if is_executable(cx) { |
| 104 | + return; |
| 105 | + } |
| 106 | + |
| 107 | + if !cx.access_levels.is_exported(it.id) { |
| 108 | + return; |
| 109 | + } |
| 110 | + match it.node { |
| 111 | + hir::ItemFn(..) => { |
| 112 | + let desc = "a function"; |
| 113 | + check_missing_inline_attrs(cx, &it.attrs, it.span, desc); |
| 114 | + }, |
| 115 | + hir::ItemTrait(ref _is_auto, ref _unsafe, ref _generics, |
| 116 | + ref _bounds, ref trait_items) => { |
| 117 | + // note: we need to check if the trait is exported so we can't use |
| 118 | + // `LateLintPass::check_trait_item` here. |
| 119 | + for tit in trait_items { |
| 120 | + let tit_ = cx.tcx.hir.trait_item(tit.id); |
| 121 | + match tit_.node { |
| 122 | + hir::TraitItemKind::Const(..) | |
| 123 | + hir::TraitItemKind::Type(..) => {}, |
| 124 | + hir::TraitItemKind::Method(..) => { |
| 125 | + if tit.defaultness.has_value() { |
| 126 | + // trait method with default body needs inline in case |
| 127 | + // an impl is not provided |
| 128 | + let desc = "a default trait method"; |
| 129 | + let item = cx.tcx.hir.expect_trait_item(tit.id.node_id); |
| 130 | + check_missing_inline_attrs(cx, &item.attrs, |
| 131 | + item.span, desc); |
| 132 | + } |
| 133 | + }, |
| 134 | + } |
| 135 | + } |
| 136 | + } |
| 137 | + hir::ItemConst(..) | |
| 138 | + hir::ItemEnum(..) | |
| 139 | + hir::ItemMod(..) | |
| 140 | + hir::ItemStatic(..) | |
| 141 | + hir::ItemStruct(..) | |
| 142 | + hir::ItemTraitAlias(..) | |
| 143 | + hir::ItemGlobalAsm(..) | |
| 144 | + hir::ItemTy(..) | |
| 145 | + hir::ItemUnion(..) | |
| 146 | + hir::ItemExistential(..) | |
| 147 | + hir::ItemExternCrate(..) | |
| 148 | + hir::ItemForeignMod(..) | |
| 149 | + hir::ItemImpl(..) | |
| 150 | + hir::ItemUse(..) => {}, |
| 151 | + }; |
| 152 | + } |
| 153 | + |
| 154 | + fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx hir::ImplItem) { |
| 155 | + use rustc::ty::{TraitContainer, ImplContainer}; |
| 156 | + if is_executable(cx) { |
| 157 | + return; |
| 158 | + } |
| 159 | + |
| 160 | + // If the item being implemented is not exported, then we don't need #[inline] |
| 161 | + if !cx.access_levels.is_exported(impl_item.id) { |
| 162 | + return; |
| 163 | + } |
| 164 | + |
| 165 | + let desc = match impl_item.node { |
| 166 | + hir::ImplItemKind::Method(..) => "a method", |
| 167 | + hir::ImplItemKind::Const(..) | |
| 168 | + hir::ImplItemKind::Type(_) => return, |
| 169 | + }; |
| 170 | + |
| 171 | + let def_id = cx.tcx.hir.local_def_id(impl_item.id); |
| 172 | + match cx.tcx.associated_item(def_id).container { |
| 173 | + TraitContainer(cid) => { |
| 174 | + if let Some(n) = cx.tcx.hir.as_local_node_id(cid) { |
| 175 | + if !cx.access_levels.is_exported(n) { |
| 176 | + // If a trait is being implemented for an item, and the |
| 177 | + // trait is not exported, we don't need #[inline] |
| 178 | + return; |
| 179 | + } |
| 180 | + } |
| 181 | + }, |
| 182 | + ImplContainer(cid) => { |
| 183 | + if cx.tcx.impl_trait_ref(cid).is_some() { |
| 184 | + let trait_ref = cx.tcx.impl_trait_ref(cid).unwrap(); |
| 185 | + if let Some(n) = cx.tcx.hir.as_local_node_id(trait_ref.def_id) { |
| 186 | + if !cx.access_levels.is_exported(n) { |
| 187 | + // If a trait is being implemented for an item, and the |
| 188 | + // trait is not exported, we don't need #[inline] |
| 189 | + return; |
| 190 | + } |
| 191 | + } |
| 192 | + } |
| 193 | + }, |
| 194 | + } |
| 195 | + |
| 196 | + check_missing_inline_attrs(cx, &impl_item.attrs, impl_item.span, desc); |
| 197 | + } |
| 198 | +} |
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