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Clean up and document the public lint API

Browse Source 
Also change some code formatting.

lint::builtin becomes a sibling of lint::context in order to ensure that lints
implemented there use the same public API as lint plugins.
This commit is contained in:
Keegan McAllister 2014-06-06 15:49:48 -07:00
parent 819f76ca82
commit c7af6060dd
5 changed files with 768 additions and 682 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/librustc/driver/driver.rs
View File

@ -384,7 +384,7 @@ pub fn phase_3_run_analysis_passes(sess: Session,
});
time(time_passes, "lint checking", (), |_|
lint::check_crate(&ty_cx, &exported_items, krate));
lint::check_crate(&ty_cx, krate, &exported_items));
CrateAnalysis {
exp_map2: exp_map2,

83
src/librustc/lint/builtin.rs
View File

@ -9,18 +9,31 @@
// except according to those terms.
//! Lints built in to rustc.
//!
//! This is a sibling of `lint::context` in order to ensure that
//! lints implemented here use the same public API as lint plugins.
//!
//! To add a new lint to rustc, declare it here using `declare_lint!()`.
//! Then add code to emit the new lint in the appropriate circumstances.
//! You can do that in an existing `LintPass` if it makes sense, or in
//! a new `LintPass`, or using `Session::add_lint` elsewhere in the
//! compiler. Only do the latter if the check can't be written cleanly
//! as a `LintPass`.
//!
//! If you define a new `LintPass`, you will also need to add it to the
//! `add_builtin_lints!()` invocation in `context.rs`. That macro
//! requires a `Default` impl for your `LintPass` type.
use metadata::csearch;
use middle::def::*;
use middle::trans::adt; // for `adt::is_ffi_safe`
use middle::typeck::astconv::{ast_ty_to_ty, AstConv};
use middle::typeck::astconv::ast_ty_to_ty;
use middle::typeck::infer;
use middle::privacy::ExportedItems;
use middle::{typeck, ty, def, pat_util};
use util::ppaux::{ty_to_str};
use util::nodemap::NodeSet;
use lint::{Context, LintPass, LintArray};
use lint;
use std::cmp;
use std::collections::HashMap;
@ -169,7 +182,7 @@ impl LintPass for TypeLimits {
match ty::get(ty::expr_ty(cx.tcx, e)).sty {
ty::ty_int(t) => {
let int_type = if t == ast::TyI {
cx.tcx.sess.targ_cfg.int_type
cx.sess().targ_cfg.int_type
} else { t };
let (min, max) = int_ty_range(int_type);
let mut lit_val: i64 = match lit.node {
@ -188,7 +201,7 @@ impl LintPass for TypeLimits {
},
ty::ty_uint(t) => {
let uint_type = if t == ast::TyU {
cx.tcx.sess.targ_cfg.uint_type
cx.sess().targ_cfg.uint_type
} else { t };
let (min, max) = uint_ty_range(uint_type);
let lit_val: u64 = match lit.node {
@ -430,9 +443,9 @@ impl LintPass for HeapMemory {
ast::ItemFn(..) |
ast::ItemTy(..) |
ast::ItemEnum(..) |
ast::ItemStruct(..) => self.check_heap_type(cx, it.span,
ty::node_id_to_type(cx.tcx,
it.id)),
ast::ItemStruct(..)
=> self.check_heap_type(cx, it.span,
ty::node_id_to_type(cx.tcx, it.id)),
_ => ()
}
@ -441,8 +454,7 @@ impl LintPass for HeapMemory {
ast::ItemStruct(struct_def, _) => {
for struct_field in struct_def.fields.iter() {
self.check_heap_type(cx, struct_field.span,
ty::node_id_to_type(cx.tcx,
struct_field.node.id));
ty::node_id_to_type(cx.tcx, struct_field.node.id));
}
}
_ => ()
@ -677,7 +689,7 @@ impl LintPass for UnusedResult {
_ => {}
}
} else {
csearch::get_item_attrs(&cx.tcx.sess.cstore, did, |attrs| {
csearch::get_item_attrs(&cx.sess().cstore, did, |attrs| {
if attr::contains_name(attrs.as_slice(), "must_use") {
cx.span_lint(unused_must_use, s.span,
"unused result which must be used");
@ -711,7 +723,7 @@ impl LintPass for DeprecatedOwnedVector {
ty::ty_uniq(t) => match ty::get(t).sty {
ty::ty_vec(_, None) => {
cx.span_lint(deprecated_owned_vector, e.span,
"use of deprecated `~[]` vector; replaced by `std::vec::Vec`")
"use of deprecated `~[]` vector; replaced by `std::vec::Vec`")
}
_ => {}
},
@ -791,7 +803,7 @@ fn method_context(cx: &Context, m: &ast::Method) -> MethodContext {
};
match cx.tcx.methods.borrow().find_copy(&did) {
None => cx.tcx.sess.span_bug(m.span, "missing method descriptor?!"),
None => cx.sess().span_bug(m.span, "missing method descriptor?!"),
Some(md) => {
match md.container {
ty::TraitContainer(..) => TraitDefaultImpl,
@ -1110,15 +1122,14 @@ impl UnusedMut {
match mode {
ast::BindByValue(ast::MutMutable) => {
if path.segments.len() != 1 {
cx.tcx.sess.span_bug(p.span,
cx.sess().span_bug(p.span,
"mutable binding that doesn't consist \
of exactly one segment");
}
let ident = path.segments.get(0).identifier;
if !token::get_ident(ident).get().starts_with("_") {
mutables.insert_or_update_with(ident.name as uint, vec!(id), |_, old| {
old.push(id);
});
mutables.insert_or_update_with(ident.name as uint,
vec!(id), |_, old| { old.push(id); });
}
}
_ => {
@ -1279,7 +1290,7 @@ impl MissingDoc {
desc: &'static str) {
// If we're building a test harness, then warning about
// documentation is probably not really relevant right now.
if cx.tcx.sess.opts.test { return }
if cx.sess().opts.test { return }
// `#[doc(hidden)]` disables missing_doc check.
if self.doc_hidden() { return }
@ -1358,7 +1369,8 @@ impl LintPass for MissingDoc {
}
fn check_fn(&mut self, cx: &Context,
fk: &visit::FnKind, _: &ast::FnDecl, _: &ast::Block, _: Span, _: ast::NodeId) {
fk: &visit::FnKind, _: &ast::FnDecl,
_: &ast::Block, _: Span, _: ast::NodeId) {
match *fk {
visit::FkMethod(_, _, m) => {
// If the method is an impl for a trait, don't doc.
@ -1381,7 +1393,8 @@ impl LintPass for MissingDoc {
fn check_struct_field(&mut self, cx: &Context, sf: &ast::StructField) {
match sf.node.kind {
ast::NamedField(_, vis) if vis == ast::Public => {
let cur_struct_def = *self.struct_def_stack.last().expect("empty struct_def_stack");
let cur_struct_def = *self.struct_def_stack.last()
.expect("empty struct_def_stack");
self.check_missing_doc_attrs(cx, Some(cur_struct_def),
sf.node.attrs.as_slice(), sf.span, "a struct field")
}
@ -1404,8 +1417,8 @@ declare_lint!(experimental, Warn,
declare_lint!(unstable, Allow,
"detects use of #[unstable] items (incl. items with no stability attribute)")
/// Checks for use of items with #[deprecated], #[experimental] and
/// #[unstable] (or none of them) attributes.
/// Checks for use of items with `#[deprecated]`, `#[experimental]` and
/// `#[unstable]` attributes, or no stability attribute.
#[deriving(Default)]
pub struct Stability;
@ -1472,7 +1485,7 @@ impl LintPass for Stability {
let mut s = None;
// run through all the attributes and take the first
// stability one.
csearch::get_item_attrs(&cx.tcx.sess.cstore, id, |attrs| {
csearch::get_item_attrs(&cx.sess().cstore, id, |attrs| {
if s.is_none() {
s = attr::find_stability(attrs.as_slice())
}
@ -1503,32 +1516,6 @@ impl LintPass for Stability {
}
}
/// Doesn't actually warn; just gathers information for use by
/// checks in trans.
#[deriving(Default)]
pub struct GatherNodeLevels;
impl LintPass for GatherNodeLevels {
fn get_lints(&self) -> LintArray {
lint_array!()
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
match it.node {
ast::ItemEnum(..) => {
let lint_id = lint::LintId::of(variant_size_difference);
match cx.lints.get_level_source(lint_id) {
lvlsrc @ (lvl, _) if lvl != lint::Allow => {
cx.insert_node_level(it.id, lint_id, lvlsrc);
},
_ => { }
}
},
_ => { }
}
}
}
declare_lint!(pub unused_imports, Warn,
"imports that are never used")

628
src/librustc/lint/context.rs Normal file
View File

@ -0,0 +1,628 @@
// Copyright 2012-2014 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.
//! Implementation of lint checking.
//!
//! The lint checking is mostly consolidated into one pass which runs just
//! before translation to LLVM bytecode. Throughout compilation, lint warnings
//! can be added via the `add_lint` method on the Session structure. This
//! requires a span and an id of the node that the lint is being added to. The
//! lint isn't actually emitted at that time because it is unknown what the
//! actual lint level at that location is.
//!
//! To actually emit lint warnings/errors, a separate pass is used just before
//! translation. A context keeps track of the current state of all lint levels.
//! Upon entering a node of the ast which can modify the lint settings, the
//! previous lint state is pushed onto a stack and the ast is then recursed
//! upon. As the ast is traversed, this keeps track of the current lint level
//! for all lint attributes.
use middle::privacy::ExportedItems;
use middle::ty;
use middle::typeck::astconv::AstConv;
use middle::typeck::infer;
use driver::session::Session;
use driver::early_error;
use lint::{Level, LevelSource, Lint, LintId, LintArray, LintPass, LintPassObject};
use lint::{Default, CommandLine, Node, Allow, Warn, Deny, Forbid};
use lint::builtin;
use std::collections::HashMap;
use std::rc::Rc;
use std::cell::RefCell;
use std::default::Default;
use std::tuple::Tuple2;
use std::mem;
use syntax::ast_util::IdVisitingOperation;
use syntax::attr::AttrMetaMethods;
use syntax::attr;
use syntax::codemap::Span;
use syntax::visit::{Visitor, FnKind};
use syntax::{ast, ast_util, visit};
/// Information about the registered lints.
///
/// This is basically the subset of `Context` that we can
/// build early in the compile pipeline.
pub struct LintStore {
/// Registered lints. The bool is true if the lint was
/// added by a plugin.
lints: Vec<(&'static Lint, bool)>,
/// Trait objects for each lint pass.
passes: Vec<RefCell<LintPassObject>>,
/// Lints indexed by name.
by_name: HashMap<&'static str, LintId>,
/// Current levels of each lint, and where they were set.
levels: HashMap<LintId, LevelSource>,
}
impl LintStore {
fn get_level_source(&self, lint: LintId) -> LevelSource {
match self.levels.find(&lint) {
Some(&s) => s,
None => (Allow, Default),
}
}
fn set_level(&mut self, lint: LintId, lvlsrc: LevelSource) {
if lvlsrc.val0() == Allow {
self.levels.remove(&lint);
} else {
self.levels.insert(lint, lvlsrc);
}
}
pub fn new() -> LintStore {
LintStore {
lints: vec!(),
passes: vec!(),
by_name: HashMap::new(),
levels: HashMap::new(),
}
}
pub fn get_lints<'t>(&'t self) -> &'t [(&'static Lint, bool)] {
self.lints.as_slice()
}
pub fn register_pass(&mut self, sess: Option<&Session>,
from_plugin: bool, pass: LintPassObject) {
for &lint in pass.get_lints().iter() {
self.lints.push((lint, from_plugin));
let id = LintId::of(lint);
if !self.by_name.insert(lint.name, id) {
let msg = format!("duplicate specification of lint {}", lint.name);
match (sess, from_plugin) {
// We load builtin lints first, so a duplicate is a compiler bug.
// Use early_error when handling -W help with no crate.
(None, _) => early_error(msg.as_slice()),
(Some(sess), false) => sess.bug(msg.as_slice()),
// A duplicate name from a plugin is a user error.
(Some(sess), true) => sess.err(msg.as_slice()),
}
}
if lint.default_level != Allow {
self.levels.insert(id, (lint.default_level, Default));
}
}
self.passes.push(RefCell::new(pass));
}
pub fn register_builtin(&mut self, sess: Option<&Session>) {
macro_rules! add_builtin_lints ( ( $sess:ident, $($name:ident),*, ) => (
{$(
{
let obj: builtin::$name = Default::default();
self.register_pass($sess, false, box obj as LintPassObject);
};
)*}
))
add_builtin_lints!(sess, HardwiredLints,
WhileTrue, UnusedCasts, TypeLimits, CTypes, HeapMemory,
RawPointerDeriving, UnusedAttribute, PathStatement,
UnusedResult, DeprecatedOwnedVector, NonCamelCaseTypes,
NonSnakeCaseFunctions, NonUppercaseStatics,
NonUppercasePatternStatics, UppercaseVariables,
UnnecessaryParens, UnusedUnsafe, UnsafeBlock, UnusedMut,
UnnecessaryAllocation, MissingDoc, Stability,
)
// We have one lint pass defined in this module.
self.register_pass(sess, false, box GatherNodeLevels as LintPassObject);
}
pub fn process_command_line(&mut self, sess: &Session) {
for &(ref lint_name, level) in sess.opts.lint_opts.iter() {
match self.by_name.find_equiv(&lint_name.as_slice()) {
Some(&lint_id) => self.set_level(lint_id, (level, CommandLine)),
None => sess.err(format!("unknown {} flag: {}",
level.as_str(), lint_name).as_slice()),
}
}
}
}
/// Context for lint checking.
pub struct Context<'a> {
/// Type context we're checking in.
pub tcx: &'a ty::ctxt,
/// The store of registered lints.
lints: LintStore,
/// When recursing into an attributed node of the ast which modifies lint
/// levels, this stack keeps track of the previous lint levels of whatever
/// was modified.
level_stack: Vec<(LintId, LevelSource)>,
/// Level of lints for certain NodeIds, stored here because the body of
/// the lint needs to run in trans.
node_levels: RefCell<HashMap<(ast::NodeId, LintId), LevelSource>>,
}
/// Convenience macro for calling a `LintPass` method on every pass in the context.
macro_rules! run_lints ( ($cx:expr, $f:ident, $($args:expr),*) => (
for obj in $cx.lints.passes.iter() {
obj.borrow_mut().$f($cx, $($args),*);
}
))
/// Emit a lint as a warning or an error (or not at all)
/// according to `level`.
///
/// This lives outside of `Context` so it can be used by checks
/// in trans that run after the main lint pass is finished. Most
/// lints elsewhere in the compiler should call
/// `Session::add_lint()` instead.
pub fn raw_emit_lint(sess: &Session, lint: &'static Lint,
lvlsrc: LevelSource, span: Option<Span>, msg: &str) {
let (mut level, source) = lvlsrc;
if level == Allow { return }
let mut note = None;
let msg = match source {
Default => {
format!("{}, #[{}({})] on by default", msg,
level.as_str(), lint.name)
},
CommandLine => {
format!("{} [-{} {}]", msg,
match level {
Warn => 'W', Deny => 'D', Forbid => 'F',
Allow => fail!()
}, lint.name.replace("_", "-"))
},
Node(src) => {
note = Some(src);
msg.to_string()
}
};
// For purposes of printing, we can treat forbid as deny.
if level == Forbid { level = Deny; }
match (level, span) {
(Warn, Some(sp)) => sess.span_warn(sp, msg.as_slice()),
(Warn, None) => sess.warn(msg.as_slice()),
(Deny, Some(sp)) => sess.span_err(sp, msg.as_slice()),
(Deny, None) => sess.err(msg.as_slice()),
_ => sess.bug("impossible level in raw_emit_lint"),
}
for span in note.move_iter() {
sess.span_note(span, "lint level defined here");
}
}
impl<'a> Context<'a> {
fn new(tcx: &'a ty::ctxt) -> Context<'a> {
// We want to own the lint store, so move it out of the session.
let lint_store = mem::replace(&mut *tcx.sess.lint_store.borrow_mut(),
LintStore::new());
Context {
lints: lint_store,
tcx: tcx,
level_stack: vec!(),
node_levels: RefCell::new(HashMap::new()),
}
}
/// Get the overall compiler `Session` object.
pub fn sess(&'a self) -> &'a Session {
&self.tcx.sess
}
fn lookup_and_emit(&self, lint: &'static Lint, span: Option<Span>, msg: &str) {
let (level, src) = match self.lints.levels.find(&LintId::of(lint)) {
None => return,
Some(&(Warn, src)) => {
let lint_id = LintId::of(builtin::warnings);
(self.lints.get_level_source(lint_id).val0(), src)
}
Some(&pair) => pair,
};
raw_emit_lint(&self.tcx.sess, lint, (level, src), span, msg);
}
/// Emit a lint at the appropriate level, with no associated span.
pub fn lint(&self, lint: &'static Lint, msg: &str) {
self.lookup_and_emit(lint, None, msg);
}
/// Emit a lint at the appropriate level, for a particular span.
pub fn span_lint(&self, lint: &'static Lint, span: Span, msg: &str) {
self.lookup_and_emit(lint, Some(span), msg);
}
/**
* Merge the lints specified by any lint attributes into the
* current lint context, call the provided function, then reset the
* lints in effect to their previous state.
*/
fn with_lint_attrs(&mut self,
attrs: &[ast::Attribute],
f: |&mut Context|) {
// Parse all of the lint attributes, and then add them all to the
// current dictionary of lint information. Along the way, keep a history
// of what we changed so we can roll everything back after invoking the
// specified closure
let lint_attrs = self.gather_lint_attrs(attrs);
let mut pushed = 0u;
for (lint_id, level, span) in lint_attrs.move_iter() {
let now = self.lints.get_level_source(lint_id).val0();
if now == Forbid && level != Forbid {
let lint_name = lint_id.as_str();
self.tcx.sess.span_err(span,
format!("{}({}) overruled by outer forbid({})",
level.as_str(), lint_name, lint_name).as_slice());
} else if now != level {
let src = self.lints.get_level_source(lint_id).val1();
self.level_stack.push((lint_id, (now, src)));
pushed += 1;
self.lints.set_level(lint_id, (level, Node(span)));
}
}
run_lints!(self, enter_lint_attrs, attrs);
f(self);
run_lints!(self, exit_lint_attrs, attrs);
// rollback
for _ in range(0, pushed) {
let (lint, lvlsrc) = self.level_stack.pop().unwrap();
self.lints.set_level(lint, lvlsrc);
}
}
fn visit_ids(&self, f: |&mut ast_util::IdVisitor<Context>|) {
let mut v = ast_util::IdVisitor {
operation: self,
pass_through_items: false,
visited_outermost: false,
};
f(&mut v);
}
fn gather_lint_attrs(&mut self, attrs: &[ast::Attribute]) -> Vec<(LintId, Level, Span)> {
// Doing this as an iterator is messy due to multiple borrowing.
// Allocating and copying these should be quick.
let mut out = vec!();
for attr in attrs.iter() {
let level = match Level::from_str(attr.name().get()) {
None => continue,
Some(lvl) => lvl,
};
attr::mark_used(attr);
let meta = attr.node.value;
let metas = match meta.node {
ast::MetaList(_, ref metas) => metas,
_ => {
self.tcx.sess.span_err(meta.span, "malformed lint attribute");
continue;
}
};
for meta in metas.iter() {
match meta.node {
ast::MetaWord(ref lint_name) => {
match self.lints.by_name.find_equiv(lint_name) {
Some(lint_id) => out.push((*lint_id, level, meta.span)),
None => self.span_lint(builtin::unrecognized_lint,
meta.span,
format!("unknown `{}` attribute: `{}`",
level.as_str(), lint_name).as_slice()),
}
}
_ => self.tcx.sess.span_err(meta.span, "malformed lint attribute"),
}
}
}
out
}
}
impl<'a> AstConv for Context<'a>{
fn tcx<'a>(&'a self) -> &'a ty::ctxt { self.tcx }
fn get_item_ty(&self, id: ast::DefId) -> ty::ty_param_bounds_and_ty {
ty::lookup_item_type(self.tcx, id)
}
fn get_trait_def(&self, id: ast::DefId) -> Rc<ty::TraitDef> {
ty::lookup_trait_def(self.tcx, id)
}
fn ty_infer(&self, _span: Span) -> ty::t {
infer::new_infer_ctxt(self.tcx).next_ty_var()
}
}
impl<'a> Visitor<()> for Context<'a> {
fn visit_item(&mut self, it: &ast::Item, _: ()) {
self.with_lint_attrs(it.attrs.as_slice(), |cx| {
run_lints!(cx, check_item, it);
cx.visit_ids(|v| v.visit_item(it, ()));
visit::walk_item(cx, it, ());
})
}
fn visit_foreign_item(&mut self, it: &ast::ForeignItem, _: ()) {
self.with_lint_attrs(it.attrs.as_slice(), |cx| {
run_lints!(cx, check_foreign_item, it);
visit::walk_foreign_item(cx, it, ());
})
}
fn visit_view_item(&mut self, i: &ast::ViewItem, _: ()) {
self.with_lint_attrs(i.attrs.as_slice(), |cx| {
run_lints!(cx, check_view_item, i);
cx.visit_ids(|v| v.visit_view_item(i, ()));
visit::walk_view_item(cx, i, ());
})
}
fn visit_pat(&mut self, p: &ast::Pat, _: ()) {
run_lints!(self, check_pat, p);
visit::walk_pat(self, p, ());
}
fn visit_expr(&mut self, e: &ast::Expr, _: ()) {
run_lints!(self, check_expr, e);
visit::walk_expr(self, e, ());
}
fn visit_stmt(&mut self, s: &ast::Stmt, _: ()) {
run_lints!(self, check_stmt, s);
visit::walk_stmt(self, s, ());
}
fn visit_fn(&mut self, fk: &FnKind, decl: &ast::FnDecl,
body: &ast::Block, span: Span, id: ast::NodeId, _: ()) {
match *fk {
visit::FkMethod(_, _, m) => {
self.with_lint_attrs(m.attrs.as_slice(), |cx| {
run_lints!(cx, check_fn, fk, decl, body, span, id);
cx.visit_ids(|v| {
v.visit_fn(fk, decl, body, span, id, ());
});
visit::walk_fn(cx, fk, decl, body, span, ());
})
},
_ => {
run_lints!(self, check_fn, fk, decl, body, span, id);
visit::walk_fn(self, fk, decl, body, span, ());
}
}
}
fn visit_ty_method(&mut self, t: &ast::TypeMethod, _: ()) {
self.with_lint_attrs(t.attrs.as_slice(), |cx| {
run_lints!(cx, check_ty_method, t);
visit::walk_ty_method(cx, t, ());
})
}
fn visit_struct_def(&mut self,
s: &ast::StructDef,
ident: ast::Ident,
g: &ast::Generics,
id: ast::NodeId,
_: ()) {
run_lints!(self, check_struct_def, s, ident, g, id);
visit::walk_struct_def(self, s, ());
run_lints!(self, check_struct_def_post, s, ident, g, id);
}
fn visit_struct_field(&mut self, s: &ast::StructField, _: ()) {
self.with_lint_attrs(s.node.attrs.as_slice(), |cx| {
run_lints!(cx, check_struct_field, s);
visit::walk_struct_field(cx, s, ());
})
}
fn visit_variant(&mut self, v: &ast::Variant, g: &ast::Generics, _: ()) {
self.with_lint_attrs(v.node.attrs.as_slice(), |cx| {
run_lints!(cx, check_variant, v, g);
visit::walk_variant(cx, v, g, ());
})
}
// FIXME(#10894) should continue recursing
fn visit_ty(&mut self, t: &ast::Ty, _: ()) {
run_lints!(self, check_ty, t);
}
fn visit_ident(&mut self, sp: Span, id: ast::Ident, _: ()) {
run_lints!(self, check_ident, sp, id);
}
fn visit_mod(&mut self, m: &ast::Mod, s: Span, n: ast::NodeId, _: ()) {
run_lints!(self, check_mod, m, s, n);
visit::walk_mod(self, m, ());
}
fn visit_local(&mut self, l: &ast::Local, _: ()) {
run_lints!(self, check_local, l);
visit::walk_local(self, l, ());
}
fn visit_block(&mut self, b: &ast::Block, _: ()) {
run_lints!(self, check_block, b);
visit::walk_block(self, b, ());
}
fn visit_arm(&mut self, a: &ast::Arm, _: ()) {
run_lints!(self, check_arm, a);
visit::walk_arm(self, a, ());
}
fn visit_decl(&mut self, d: &ast::Decl, _: ()) {
run_lints!(self, check_decl, d);
visit::walk_decl(self, d, ());
}
fn visit_expr_post(&mut self, e: &ast::Expr, _: ()) {
run_lints!(self, check_expr_post, e);
}
fn visit_generics(&mut self, g: &ast::Generics, _: ()) {
run_lints!(self, check_generics, g);
visit::walk_generics(self, g, ());
}
fn visit_trait_method(&mut self, m: &ast::TraitMethod, _: ()) {
run_lints!(self, check_trait_method, m);
visit::walk_trait_method(self, m, ());
}
fn visit_opt_lifetime_ref(&mut self, sp: Span, lt: &Option<ast::Lifetime>, _: ()) {
run_lints!(self, check_opt_lifetime_ref, sp, lt);
}
fn visit_lifetime_ref(&mut self, lt: &ast::Lifetime, _: ()) {
run_lints!(self, check_lifetime_ref, lt);
}
fn visit_lifetime_decl(&mut self, lt: &ast::Lifetime, _: ()) {
run_lints!(self, check_lifetime_decl, lt);
}
fn visit_explicit_self(&mut self, es: &ast::ExplicitSelf, _: ()) {
run_lints!(self, check_explicit_self, es);
visit::walk_explicit_self(self, es, ());
}
fn visit_mac(&mut self, mac: &ast::Mac, _: ()) {
run_lints!(self, check_mac, mac);
visit::walk_mac(self, mac, ());
}
fn visit_path(&mut self, p: &ast::Path, id: ast::NodeId, _: ()) {
run_lints!(self, check_path, p, id);
visit::walk_path(self, p, ());
}
fn visit_attribute(&mut self, attr: &ast::Attribute, _: ()) {
run_lints!(self, check_attribute, attr);
}
}
// Output any lints that were previously added to the session.
impl<'a> IdVisitingOperation for Context<'a> {
fn visit_id(&self, id: ast::NodeId) {
match self.tcx.sess.lints.borrow_mut().pop(&id) {
None => {}
Some(lints) => {
for (lint_id, span, msg) in lints.move_iter() {
self.span_lint(lint_id.lint, span, msg.as_slice())
}
}
}
}
}
// This lint pass is defined here because it touches parts of the `Context`
// that we don't want to expose. It records the lint level at certain AST
// nodes, so that the variant size difference check in trans can call
// `raw_emit_lint`.
struct GatherNodeLevels;
impl LintPass for GatherNodeLevels {
fn get_lints(&self) -> LintArray {
lint_array!()
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
match it.node {
ast::ItemEnum(..) => {
let lint_id = LintId::of(builtin::variant_size_difference);
match cx.lints.get_level_source(lint_id) {
lvlsrc @ (lvl, _) if lvl != Allow => {
cx.node_levels.borrow_mut()
.insert((it.id, lint_id), lvlsrc);
},
_ => { }
}
},
_ => { }
}
}
}
/// Perform lint checking on a crate.
///
/// Consumes the `lint_store` field of the `Session`.
pub fn check_crate(tcx: &ty::ctxt,
krate: &ast::Crate,
exported_items: &ExportedItems) {
let mut cx = Context::new(tcx);
// Visit the whole crate.
cx.with_lint_attrs(krate.attrs.as_slice(), |cx| {
cx.visit_id(ast::CRATE_NODE_ID);
cx.visit_ids(|v| {
v.visited_outermost = true;
visit::walk_crate(v, krate, ());
});
// since the root module isn't visited as an item (because it isn't an
// item), warn for it here.
run_lints!(cx, check_crate, exported_items, krate);
visit::walk_crate(cx, krate, ());
});
// If we missed any lints added to the session, then there's a bug somewhere
// in the iteration code.
for (id, v) in tcx.sess.lints.borrow().iter() {
for &(lint, span, ref msg) in v.iter() {
tcx.sess.span_bug(span,
format!("unprocessed lint {} at {}: {}",
lint.as_str(), tcx.map.node_to_str(*id), *msg)
.as_slice())
}
}
tcx.sess.abort_if_errors();
*tcx.node_lint_levels.borrow_mut() = cx.node_levels.unwrap();
}

654
src/librustc/lint/mod.rs
View File

@ -8,65 +8,55 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Lints, aka compiler warnings.
//!
//! A 'lint' check is a kind of miscellaneous constraint that a user _might_
//! want to enforce, but might reasonably want to permit as well, on a
//! module-by-module basis. They contrast with static constraints enforced by
//! other phases of the compiler, which are generally required to hold in order
//! to compile the program at all.
//!
//! The lint checking is all consolidated into one pass which runs just before
//! translation to LLVM bytecode. Throughout compilation, lint warnings can be
//! added via the `add_lint` method on the Session structure. This requires a
//! span and an id of the node that the lint is being added to. The lint isn't
//! actually emitted at that time because it is unknown what the actual lint
//! level at that location is.
//! Most lints can be written as `LintPass` instances. These run just before
//! translation to LLVM bytecode. The `LintPass`es built into rustc are defined
//! within `builtin.rs`, which has further comments on how to add such a lint.
//!
//! To actually emit lint warnings/errors, a separate pass is used just before
//! translation. A context keeps track of the current state of all lint levels.
//! Upon entering a node of the ast which can modify the lint settings, the
//! previous lint state is pushed onto a stack and the ast is then recursed
//! upon. As the ast is traversed, this keeps track of the current lint level
//! for all lint attributes.
//!
//! Most of the lints built into `rustc` are structs implementing `LintPass`,
//! and are defined within `builtin.rs`. To add a new lint you can define such
//! a struct and add it to the `builtin_lints!` macro invocation in this file.
//! `LintPass` itself is not a subtrait of `Default`, but the `builtin_lints!`
//! macro requires `Default` (usually via `deriving`).
//!
//! Some lints are defined elsewhere in the compiler and work by calling
//! `add_lint()` on the overall `Session` object.
//!
//! If you're adding lints to the `Context` infrastructure itself, defined in
//! this file, use `span_lint` instead of `add_lint`.
//! Some of rustc's lints are defined elsewhere in the compiler and work by
//! calling `add_lint()` on the overall `Session` object. This works when
//! it happens before the main lint pass, which emits the lints stored by
//! `add_lint()`. To emit lints after the main lint pass (from trans, for
//! example) requires more effort. See `emit_lint` and `GatherNodeLevels`
//! in `context.rs`.
#![allow(non_camel_case_types)]
#![macro_escape]
use middle::privacy::ExportedItems;
use middle::ty;
use middle::typeck::astconv::AstConv;
use middle::typeck::infer;
use driver::session::Session;
use driver::early_error;
use std::collections::HashMap;
use std::rc::Rc;
use std::gc::Gc;
use std::to_str::ToStr;
use std::cell::RefCell;
use std::default::Default;
use std::hash::Hash;
use std::tuple::Tuple2;
use std::hash;
use std::mem;
use syntax::ast_util::IdVisitingOperation;
use syntax::attr::AttrMetaMethods;
use syntax::attr;
use syntax::codemap::Span;
use syntax::visit::{Visitor, FnKind};
use syntax::{ast, ast_util, visit};
use syntax::visit::FnKind;
use syntax::ast;
pub use lint::context::{Context, LintStore, raw_emit_lint, check_crate};
/// Specification of a single lint.
pub struct Lint {
/// A string identifier for the lint.
///
/// Written with underscores, e.g. "unused_imports".
/// This identifies the lint in attributes and in
/// command-line arguments. On the command line,
/// underscores become dashes.
pub name: &'static str,
/// Default level for the lint.
pub default_level: Level,
/// Description of the lint or the issue it detects.
///
/// e.g. "imports that are never used"
pub desc: &'static str,
}
/// Build a `Lint` initializer.
#[macro_export]
macro_rules! lint_initializer (
($name:ident, $level:ident, $desc:expr) => (
@ -78,6 +68,7 @@ macro_rules! lint_initializer (
)
)
/// Declare a static item of type `&'static Lint`.
#[macro_export]
macro_rules! declare_lint (
// FIXME(#14660): deduplicate
@ -91,6 +82,7 @@ macro_rules! declare_lint (
);
)
/// Declare a static `LintArray` and return it as an expression.
#[macro_export]
macro_rules! lint_array ( ($( $lint:expr ),*) => (
{
@ -99,29 +91,13 @@ macro_rules! lint_array ( ($( $lint:expr ),*) => (
}
))
pub mod builtin;
/// Specification of a single lint.
pub struct Lint {
/// An identifier for the lint, written with underscores,
/// e.g. "unused_imports". This identifies the lint in
/// attributes and in command-line arguments. On the
/// command line, underscores become dashes.
pub name: &'static str,
/// Default level for the lint.
pub default_level: Level,
/// Description of the lint or the issue it detects,
/// e.g. "imports that are never used"
pub desc: &'static str,
}
pub type LintArray = &'static [&'static Lint];
/// Trait for types providing lint checks. Each `check` method checks a single
/// syntax node, and should not invoke methods recursively (unlike `Visitor`).
/// By default they do nothing.
/// Trait for types providing lint checks.
///
/// Each `check` method checks a single syntax node, and should not
/// invoke methods recursively (unlike `Visitor`). By default they
/// do nothing.
//
// FIXME: eliminate the duplication with `Visitor`. But this also
// contains a few lint-specific methods with no equivalent in `Visitor`.
@ -176,7 +152,8 @@ pub trait LintPass {
fn exit_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) { }
}
type LintPassObject = Box<LintPass + 'static>;
/// A lint pass boxed up as a trait object.
pub type LintPassObject = Box<LintPass + 'static>;
/// Identifies a lint known to the compiler.
#[deriving(Clone)]
@ -193,7 +170,7 @@ impl PartialEq for LintId {
impl Eq for LintId { }
impl<S: hash::Writer> Hash<S> for LintId {
impl<S: hash::Writer> hash::Hash<S> for LintId {
fn hash(&self, state: &mut S) {
let ptr = self.lint as *Lint;
ptr.hash(state);
@ -201,23 +178,27 @@ impl<S: hash::Writer> Hash<S> for LintId {
}
impl LintId {
/// Get the `LintId` for a `Lint`.
pub fn of(lint: &'static Lint) -> LintId {
LintId {
lint: lint,
}
}
/// Get the name of the lint.
pub fn as_str(&self) -> &'static str {
self.lint.name
}
}
/// Setting for how to handle a lint.
#[deriving(Clone, PartialEq, PartialOrd, Eq, Ord)]
pub enum Level {
Allow, Warn, Deny, Forbid
}
impl Level {
/// Convert a level to a lower-case string.
pub fn as_str(self) -> &'static str {
match self {
Allow => "allow",
@ -227,6 +208,7 @@ impl Level {
}
}
/// Convert a lower-case string to a level.
pub fn from_str(x: &str) -> Option<Level> {
match x {
"allow" => Some(Allow),
@ -238,534 +220,22 @@ impl Level {
}
}
// this is public for the lints that run in trans
#[deriving(PartialEq)]
/// How a lint level was set.
#[deriving(Clone, PartialEq, Eq)]
pub enum LintSource {
Node(Span),
/// Lint is at the default level as declared
/// in rustc or a plugin.
Default,
CommandLine
/// Lint level was set by an attribute.
Node(Span),
/// Lint level was set by a command-line flag.
CommandLine,
}
pub type LevelSource = (Level, LintSource);
/// Information about the registered lints.
/// This is basically the subset of `Context` that we can
/// build early in the compile pipeline.
pub struct LintStore {
/// Registered lints. The bool is true if the lint was
/// added by a plugin.
lints: Vec<(&'static Lint, bool)>,
pub mod builtin;
/// Trait objects for each lint pass.
passes: Vec<RefCell<LintPassObject>>,
/// Lints indexed by name.
by_name: HashMap<&'static str, LintId>,
/// Current levels of each lint, and where they were set.
levels: HashMap<LintId, LevelSource>,
}
impl LintStore {
fn get_level_source(&self, lint: LintId) -> LevelSource {
match self.levels.find(&lint) {
Some(&s) => s,
None => (Allow, Default),
}
}
fn set_level(&mut self, lint: LintId, lvlsrc: LevelSource) {
if lvlsrc.val0() == Allow {
self.levels.remove(&lint);
} else {
self.levels.insert(lint, lvlsrc);
}
}
pub fn new() -> LintStore {
LintStore {
lints: vec!(),
passes: vec!(),
by_name: HashMap::new(),
levels: HashMap::new(),
}
}
pub fn get_lints<'t>(&'t self) -> &'t [(&'static Lint, bool)] {
self.lints.as_slice()
}
pub fn register_pass(&mut self, sess: Option<&Session>,
from_plugin: bool, pass: LintPassObject) {
for &lint in pass.get_lints().iter() {
self.lints.push((lint, from_plugin));
let id = LintId::of(lint);
if !self.by_name.insert(lint.name, id) {
let msg = format!("duplicate specification of lint {}", lint.name);
match (sess, from_plugin) {
// We load builtin lints first, so a duplicate is a compiler bug.
// Use early_error when handling -W help with no crate.
(None, _) => early_error(msg.as_slice()),
(Some(sess), false) => sess.bug(msg.as_slice()),
// A duplicate name from a plugin is a user error.
(Some(sess), true) => sess.err(msg.as_slice()),
}
}
if lint.default_level != Allow {
self.levels.insert(id, (lint.default_level, Default));
}
}
self.passes.push(RefCell::new(pass));
}
pub fn register_builtin(&mut self, sess: Option<&Session>) {
macro_rules! add_builtin_lints ( ( $sess:ident, $($name:ident),*, ) => (
{$(
{
let obj: builtin::$name = Default::default();
self.register_pass($sess, false, box obj as LintPassObject);
};
)*}
))
add_builtin_lints!(sess,
WhileTrue, UnusedCasts, TypeLimits, CTypes, HeapMemory,
RawPointerDeriving, UnusedAttribute, PathStatement,
UnusedResult, DeprecatedOwnedVector, NonCamelCaseTypes,
NonSnakeCaseFunctions, NonUppercaseStatics,
NonUppercasePatternStatics, UppercaseVariables,
UnnecessaryParens, UnusedUnsafe, UnsafeBlock, UnusedMut,
UnnecessaryAllocation, MissingDoc, Stability,
GatherNodeLevels, HardwiredLints,
)
}
pub fn process_command_line(&mut self, sess: &Session) {
for &(ref lint_name, level) in sess.opts.lint_opts.iter() {
match self.by_name.find_equiv(&lint_name.as_slice()) {
Some(&lint_id) => self.set_level(lint_id, (level, CommandLine)),
None => sess.err(format!("unknown {} flag: {}",
level.as_str(), lint_name).as_slice()),
}
}
}
}
/// Context for lint checking.
pub struct Context<'a> {
/// The store of registered lints.
lints: LintStore,
/// Context we're checking in (used to access fields like sess).
tcx: &'a ty::ctxt,
/// When recursing into an attributed node of the ast which modifies lint
/// levels, this stack keeps track of the previous lint levels of whatever
/// was modified.
level_stack: Vec<(LintId, LevelSource)>,
/// Level of lints for certain NodeIds, stored here because the body of
/// the lint needs to run in trans.
node_levels: RefCell<HashMap<(ast::NodeId, LintId), LevelSource>>,
}
/// Convenience macro for calling a `LintPass` method on every pass in the context.
macro_rules! run_lints ( ($cx:expr, $f:ident, $($args:expr),*) => (
for obj in $cx.lints.passes.iter() {
obj.borrow_mut().$f($cx, $($args),*);
}
))
/// Emit a lint as a `span_warn` or `span_err` (or not at all)
/// according to `level`. This lives outside of `Context` so
/// it can be used by checks in trans that run after the main
/// lint phase is finished.
pub fn emit_lint(sess: &Session, lint: &'static Lint,
lvlsrc: LevelSource, span: Span, msg: &str) {
let (level, source) = lvlsrc;
if level == Allow { return }
let mut note = None;
let msg = match source {
Default => {
format!("{}, #[{}({})] on by default", msg,
level_to_str(level), lint_str)
},
CommandLine => {
format!("{} [-{} {}]", msg,
match level {
Warn => 'W', Deny => 'D', Forbid => 'F',
Allow => fail!()
}, lint.name.replace("_", "-"))
},
Node(src) => {
note = Some(src);
msg.to_string()
}
};
match level {
Warn => { sess.span_warn(span, msg.as_slice()); }
Deny | Forbid => { sess.span_err(span, msg.as_slice()); }
Allow => fail!(),
}
for span in note.move_iter() {
sess.span_note(span, "lint level defined here");
}
}
impl<'a> Context<'a> {
pub fn span_lint(&self, lint: &'static Lint, span: Span, msg: &str) {
let (level, src) = match self.lints.levels.find(&LintId::of(lint)) {
None => return,
Some(&(Warn, src))
=> (self.lints.get_level_source(LintId::of(builtin::warnings)).val0(), src),
Some(&pair) => pair,
};
emit_lint(&self.tcx.sess, lint, (level, src), span, msg);
}
/**
* Merge the lints specified by any lint attributes into the
* current lint context, call the provided function, then reset the
* lints in effect to their previous state.
*/
fn with_lint_attrs(&mut self,
attrs: &[ast::Attribute],
f: |&mut Context|) {
// Parse all of the lint attributes, and then add them all to the
// current dictionary of lint information. Along the way, keep a history
// of what we changed so we can roll everything back after invoking the
// specified closure
let lint_attrs = self.gather_lint_attrs(attrs);
let mut pushed = 0u;
for (lint_id, level, span) in lint_attrs.move_iter() {
let now = self.lints.get_level_source(lint_id).val0();
if now == Forbid && level != Forbid {
let lint_name = lint_id.as_str();
self.tcx.sess.span_err(span,
format!("{}({}) overruled by outer forbid({})",
level.as_str(), lint_name, lint_name).as_slice());
} else if now != level {
let src = self.lints.get_level_source(lint_id).val1();
self.level_stack.push((lint_id, (now, src)));
pushed += 1;
self.lints.set_level(lint_id, (level, Node(span)));
}
}
run_lints!(self, enter_lint_attrs, attrs);
f(self);
run_lints!(self, exit_lint_attrs, attrs);
// rollback
for _ in range(0, pushed) {
let (lint, lvlsrc) = self.level_stack.pop().unwrap();
self.lints.set_level(lint, lvlsrc);
}
}
fn visit_ids(&self, f: |&mut ast_util::IdVisitor<Context>|) {
let mut v = ast_util::IdVisitor {
operation: self,
pass_through_items: false,
visited_outermost: false,
};
f(&mut v);
}
fn insert_node_level(&self, id: ast::NodeId, lint: LintId, lvlsrc: LevelSource) {
self.node_levels.borrow_mut().insert((id, lint), lvlsrc);
}
fn gather_lint_attrs(&mut self, attrs: &[ast::Attribute]) -> Vec<(LintId, Level, Span)> {
// Doing this as an iterator is messy due to multiple borrowing.
// Allocating and copying these should be quick.
let mut out = vec!();
for attr in attrs.iter() {
let level = match Level::from_str(attr.name().get()) {
None => continue,
Some(lvl) => lvl,
};
attr::mark_used(attr);
let meta = attr.node.value;
let metas = match meta.node {
ast::MetaList(_, ref metas) => metas,
_ => {
self.tcx.sess.span_err(meta.span, "malformed lint attribute");
continue;
}
};
for meta in metas.iter() {
match meta.node {
ast::MetaWord(ref lint_name) => {
match self.lints.by_name.find_equiv(lint_name) {
Some(lint_id) => out.push((*lint_id, level, meta.span)),
None => self.span_lint(builtin::unrecognized_lint,
meta.span,
format!("unknown `{}` attribute: `{}`",
level.as_str(), lint_name).as_slice()),
}
}
_ => self.tcx.sess.span_err(meta.span, "malformed lint attribute"),
}
}
}
out
}
}
impl<'a> AstConv for Context<'a>{
fn tcx<'a>(&'a self) -> &'a ty::ctxt { self.tcx }
fn get_item_ty(&self, id: ast::DefId) -> ty::ty_param_bounds_and_ty {
ty::lookup_item_type(self.tcx, id)
}
fn get_trait_def(&self, id: ast::DefId) -> Rc<ty::TraitDef> {
ty::lookup_trait_def(self.tcx, id)
}
fn ty_infer(&self, _span: Span) -> ty::t {
infer::new_infer_ctxt(self.tcx).next_ty_var()
}
}
impl<'a> Visitor<()> for Context<'a> {
fn visit_item(&mut self, it: &ast::Item, _: ()) {
self.with_lint_attrs(it.attrs.as_slice(), |cx| {
run_lints!(cx, check_item, it);
cx.visit_ids(|v| v.visit_item(it, ()));
visit::walk_item(cx, it, ());
})
}
fn visit_foreign_item(&mut self, it: &ast::ForeignItem, _: ()) {
self.with_lint_attrs(it.attrs.as_slice(), |cx| {
run_lints!(cx, check_foreign_item, it);
visit::walk_foreign_item(cx, it, ());
})
}
fn visit_view_item(&mut self, i: &ast::ViewItem, _: ()) {
self.with_lint_attrs(i.attrs.as_slice(), |cx| {
run_lints!(cx, check_view_item, i);
cx.visit_ids(|v| v.visit_view_item(i, ()));
visit::walk_view_item(cx, i, ());
})
}
fn visit_pat(&mut self, p: &ast::Pat, _: ()) {
run_lints!(self, check_pat, p);
visit::walk_pat(self, p, ());
}
fn visit_expr(&mut self, e: &ast::Expr, _: ()) {
run_lints!(self, check_expr, e);
visit::walk_expr(self, e, ());
}
fn visit_stmt(&mut self, s: &ast::Stmt, _: ()) {
run_lints!(self, check_stmt, s);
visit::walk_stmt(self, s, ());
}
fn visit_fn(&mut self, fk: &FnKind, decl: &ast::FnDecl,
body: &ast::Block, span: Span, id: ast::NodeId, _: ()) {
match *fk {
visit::FkMethod(_, _, m) => {
self.with_lint_attrs(m.attrs.as_slice(), |cx| {
run_lints!(cx, check_fn, fk, decl, body, span, id);
cx.visit_ids(|v| {
v.visit_fn(fk, decl, body, span, id, ());
});
visit::walk_fn(cx, fk, decl, body, span, ());
})
},
_ => {
run_lints!(self, check_fn, fk, decl, body, span, id);
visit::walk_fn(self, fk, decl, body, span, ());
}
}
}
fn visit_ty_method(&mut self, t: &ast::TypeMethod, _: ()) {
self.with_lint_attrs(t.attrs.as_slice(), |cx| {
run_lints!(cx, check_ty_method, t);
visit::walk_ty_method(cx, t, ());
})
}
fn visit_struct_def(&mut self,
s: &ast::StructDef,
ident: ast::Ident,
g: &ast::Generics,
id: ast::NodeId,
_: ()) {
run_lints!(self, check_struct_def, s, ident, g, id);
visit::walk_struct_def(self, s, ());
run_lints!(self, check_struct_def_post, s, ident, g, id);
}
fn visit_struct_field(&mut self, s: &ast::StructField, _: ()) {
self.with_lint_attrs(s.node.attrs.as_slice(), |cx| {
run_lints!(cx, check_struct_field, s);
visit::walk_struct_field(cx, s, ());
})
}
fn visit_variant(&mut self, v: &ast::Variant, g: &ast::Generics, _: ()) {
self.with_lint_attrs(v.node.attrs.as_slice(), |cx| {
run_lints!(cx, check_variant, v, g);
visit::walk_variant(cx, v, g, ());
})
}
// FIXME(#10894) should continue recursing
fn visit_ty(&mut self, t: &ast::Ty, _: ()) {
run_lints!(self, check_ty, t);
}
fn visit_ident(&mut self, sp: Span, id: ast::Ident, _: ()) {
run_lints!(self, check_ident, sp, id);
}
fn visit_mod(&mut self, m: &ast::Mod, s: Span, n: ast::NodeId, _: ()) {
run_lints!(self, check_mod, m, s, n);
visit::walk_mod(self, m, ());
}
fn visit_local(&mut self, l: &ast::Local, _: ()) {
run_lints!(self, check_local, l);
visit::walk_local(self, l, ());
}
fn visit_block(&mut self, b: &ast::Block, _: ()) {
run_lints!(self, check_block, b);
visit::walk_block(self, b, ());
}
fn visit_arm(&mut self, a: &ast::Arm, _: ()) {
run_lints!(self, check_arm, a);
visit::walk_arm(self, a, ());
}
fn visit_decl(&mut self, d: &ast::Decl, _: ()) {
run_lints!(self, check_decl, d);
visit::walk_decl(self, d, ());
}
fn visit_expr_post(&mut self, e: &ast::Expr, _: ()) {
run_lints!(self, check_expr_post, e);
}
fn visit_generics(&mut self, g: &ast::Generics, _: ()) {
run_lints!(self, check_generics, g);
visit::walk_generics(self, g, ());
}
fn visit_trait_method(&mut self, m: &ast::TraitMethod, _: ()) {
run_lints!(self, check_trait_method, m);
visit::walk_trait_method(self, m, ());
}
fn visit_opt_lifetime_ref(&mut self, sp: Span, lt: &Option<ast::Lifetime>, _: ()) {
run_lints!(self, check_opt_lifetime_ref, sp, lt);
}
fn visit_lifetime_ref(&mut self, lt: &ast::Lifetime, _: ()) {
run_lints!(self, check_lifetime_ref, lt);
}
fn visit_lifetime_decl(&mut self, lt: &ast::Lifetime, _: ()) {
run_lints!(self, check_lifetime_decl, lt);
}
fn visit_explicit_self(&mut self, es: &ast::ExplicitSelf, _: ()) {
run_lints!(self, check_explicit_self, es);
visit::walk_explicit_self(self, es, ());
}
fn visit_mac(&mut self, mac: &ast::Mac, _: ()) {
run_lints!(self, check_mac, mac);
visit::walk_mac(self, mac, ());
}
fn visit_path(&mut self, p: &ast::Path, id: ast::NodeId, _: ()) {
run_lints!(self, check_path, p, id);
visit::walk_path(self, p, ());
}
fn visit_attribute(&mut self, attr: &ast::Attribute, _: ()) {
run_lints!(self, check_attribute, attr);
}
}
// Output any lints that were previously added to the session.
impl<'a> IdVisitingOperation for Context<'a> {
fn visit_id(&self, id: ast::NodeId) {
match self.tcx.sess.lints.borrow_mut().pop(&id) {
None => {}
Some(lints) => {
for (lint_id, span, msg) in lints.move_iter() {
self.span_lint(lint_id.lint, span, msg.as_slice())
}
}
}
}
}
pub fn check_crate(tcx: &ty::ctxt,
exported_items: &ExportedItems,
krate: &ast::Crate) {
// We want to own the lint store, so move it out of the session.
let lint_store = mem::replace(&mut *tcx.sess.lint_store.borrow_mut(),
LintStore::new());
let mut cx = Context {
lints: lint_store,
tcx: tcx,
level_stack: Vec::new(),
node_levels: RefCell::new(HashMap::new()),
};
// Visit the whole crate.
cx.with_lint_attrs(krate.attrs.as_slice(), |cx| {
cx.visit_id(ast::CRATE_NODE_ID);
cx.visit_ids(|v| {
v.visited_outermost = true;
visit::walk_crate(v, krate, ());
});
// since the root module isn't visited as an item (because it isn't an
// item), warn for it here.
run_lints!(cx, check_crate, exported_items, krate);
visit::walk_crate(cx, krate, ());
});
// If we missed any lints added to the session, then there's a bug somewhere
// in the iteration code.
for (id, v) in tcx.sess.lints.borrow().iter() {
for &(lint, span, ref msg) in v.iter() {
tcx.sess.span_bug(span,
format!("unprocessed lint {} at {}: {}",
lint.as_str(), tcx.map.node_to_str(*id), *msg)
.as_slice())
}
}
tcx.sess.abort_if_errors();
*tcx.node_lint_levels.borrow_mut() = cx.node_levels.unwrap();
}
mod context;

83
src/librustc/middle/trans/base.rs
View File

@ -1553,50 +1553,51 @@ fn enum_variant_size_lint(ccx: &CrateContext, enum_def: &ast::EnumDef, sp: Span,
let mut sizes = Vec::new(); // does no allocation if no pushes, thankfully
let levels = ccx.tcx.node_lint_levels.borrow();
match levels.find(&(id, lint::LintId::of(lint::builtin::variant_size_difference))) {
None | Some(&(lint::Allow, _)) => (),
Some(&lvlsrc) => {
let avar = adt::represent_type(ccx, ty::node_id_to_type(ccx.tcx(), id));
match *avar {
adt::General(_, ref variants) => {
for var in variants.iter() {
let mut size = 0;
for field in var.fields.iter().skip(1) {
// skip the discriminant
size += llsize_of_real(ccx, sizing_type_of(ccx, *field));
}
sizes.push(size);
}
},
_ => { /* its size is either constant or unimportant */ }
let lint_id = lint::LintId::of(lint::builtin::variant_size_difference);
let lvlsrc = match levels.find(&(id, lint_id)) {
None | Some(&(lint::Allow, _)) => return,
Some(&lvlsrc) => lvlsrc,
};
let avar = adt::represent_type(ccx, ty::node_id_to_type(ccx.tcx(), id));
match *avar {
adt::General(_, ref variants) => {
for var in variants.iter() {
let mut size = 0;
for field in var.fields.iter().skip(1) {
// skip the discriminant
size += llsize_of_real(ccx, sizing_type_of(ccx, *field));
}
sizes.push(size);
}
},
_ => { /* its size is either constant or unimportant */ }
}
let (largest, slargest, largest_index) = sizes.iter().enumerate().fold((0, 0, 0),
|(l, s, li), (idx, &size)|
if size > l {
(size, l, idx)
} else if size > s {
(l, size, li)
} else {
(l, s, li)
}
);
// we only warn if the largest variant is at least thrice as large as
// the second-largest.
if largest > slargest * 3 && slargest > 0 {
// Use lint::emit_lint rather than sess.add_lint because the lint-printing
// pass for the latter already ran.
lint::emit_lint(&ccx.tcx().sess, lint::builtin::variant_size_difference,
lvlsrc, sp,
format!("enum variant is more than three times larger \
({} bytes) than the next largest (ignoring padding)",
largest).as_slice());
ccx.sess().span_note(enum_def.variants.get(largest_index).span,
"this variant is the largest");
let (largest, slargest, largest_index) = sizes.iter().enumerate().fold((0, 0, 0),
|(l, s, li), (idx, &size)|
if size > l {
(size, l, idx)
} else if size > s {
(l, size, li)
} else {
(l, s, li)
}
}
);
// we only warn if the largest variant is at least thrice as large as
// the second-largest.
if largest > slargest * 3 && slargest > 0 {
// Use lint::raw_emit_lint rather than sess.add_lint because the lint-printing
// pass for the latter already ran.
lint::raw_emit_lint(&ccx.tcx().sess, lint::builtin::variant_size_difference,
lvlsrc, Some(sp),
format!("enum variant is more than three times larger \
({} bytes) than the next largest (ignoring padding)",
largest).as_slice());
ccx.sess().span_note(enum_def.variants.get(largest_index).span,
"this variant is the largest");
}
}