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servo: Merge #4521 - break up lints.rs into separate files (from ajnirp:separate-lints); r=Manishearth

Browse Source 
for #4509

Source-Repo: https://github.com/servo/servo
Source-Revision: 685dec1abc61402ab22db93f4a362a58f8377d68
This commit is contained in:
Rohan Prinja 2015-01-01 01:33:41 -07:00
parent 55aff8daf0
commit 68992e04cf
9 changed files with 430 additions and 378 deletions
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10
servo/components/plugins/lib.rs
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@ -44,11 +44,11 @@ pub fn plugin_registrar(reg: &mut Registry) {
reg.register_syntax_extension(intern("dom_struct"), Modifier(box jstraceable::expand_dom_struct));
reg.register_syntax_extension(intern("jstraceable"), Decorator(box jstraceable::expand_jstraceable));
reg.register_syntax_extension(intern("_generate_reflector"), Decorator(box reflector::expand_reflector));
reg.register_lint_pass(box lints::TransmutePass as LintPassObject);
reg.register_lint_pass(box lints::UnrootedPass as LintPassObject);
reg.register_lint_pass(box lints::PrivatizePass as LintPassObject);
reg.register_lint_pass(box lints::InheritancePass as LintPassObject);
reg.register_lint_pass(box lints::StrToStringPass as LintPassObject);
reg.register_lint_pass(box lints::transmute_type::TransmutePass as LintPassObject);
reg.register_lint_pass(box lints::unrooted_must_root::UnrootedPass as LintPassObject);
reg.register_lint_pass(box lints::privatize::PrivatizePass as LintPassObject);
reg.register_lint_pass(box lints::inheritance_integrity::InheritancePass as LintPassObject);
reg.register_lint_pass(box lints::str_to_string::StrToStringPass as LintPassObject);
}

372
servo/components/plugins/lints.rs
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@ -1,372 +0,0 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::{ast, ast_map, ast_util, codemap, visit};
use syntax::ast::Public;
use syntax::attr::AttrMetaMethods;
use rustc::lint::{Context, LintPass, LintArray, Level};
use rustc::middle::ty::expr_ty;
use rustc::middle::{ty, def};
use rustc::middle::typeck::astconv::AstConv;
use rustc::util::ppaux::Repr;
use utils::match_lang_ty;
declare_lint!(TRANSMUTE_TYPE_LINT, Allow,
"Warn and report types being transmuted")
declare_lint!(UNROOTED_MUST_ROOT, Deny,
"Warn and report usage of unrooted jsmanaged objects")
declare_lint!(PRIVATIZE, Deny,
"Allows to enforce private fields for struct definitions")
declare_lint!(INHERITANCE_INTEGRITY, Deny,
"Ensures that struct fields are properly laid out for inheritance to work")
declare_lint!(STR_TO_STRING, Deny,
"Warn when a String could use into_string() instead of to_string()")
/// Lint for auditing transmutes
///
/// This lint (off by default, enable with `-W transmute-type-lint`) warns about all the transmutes
/// being used, along with the types they transmute to/from.
pub struct TransmutePass;
/// Lint for ensuring safe usage of unrooted pointers
///
/// This lint (disable with `-A unrooted-must-root`/`#[allow(unrooted_must_root)]`) ensures that `#[must_root]` values are used correctly.
/// "Incorrect" usage includes:
///
/// - Not being used in a struct/enum field which is not `#[must_root]` itself
/// - Not being used as an argument to a function (Except onces named `new` and `new_inherited`)
/// - Not being bound locally in a `let` statement, assignment, `for` loop, or `match` statement.
///
/// This helps catch most situations where pointers like `JS<T>` are used in a way that they can be invalidated by a GC pass.
pub struct UnrootedPass;
/// Lint for keeping DOM fields private
///
/// This lint (disable with `-A privatize`/`#[allow(privatize)]`) ensures all types marked with `#[privatize]` have no private fields
pub struct PrivatizePass;
/// Lint for ensuring proper layout of DOM structs
///
/// A DOM struct must have one Reflector field or one field
/// which itself is a DOM struct (in which case it must be the first field).
pub struct InheritancePass;
/// Prefer str.into_string() over str.to_string()
///
/// The latter creates a `Formatter` and is 5x slower than the former
pub struct StrToStringPass;
impl LintPass for TransmutePass {
fn get_lints(&self) -> LintArray {
lint_array!(TRANSMUTE_TYPE_LINT)
}
fn check_expr(&mut self, cx: &Context, ex: &ast::Expr) {
match ex.node {
ast::ExprCall(ref expr, ref args) => {
match expr.node {
ast::ExprPath(ref path) => {
if path.segments.last()
.map_or(false, |ref segment| segment.identifier.name.as_str() == "transmute")
&& args.len() == 1 {
let tcx = cx.tcx();
cx.span_lint(TRANSMUTE_TYPE_LINT, ex.span,
format!("Transmute to {} from {} detected",
expr_ty(tcx, ex).repr(tcx),
expr_ty(tcx, &**args.get(0).unwrap()).repr(tcx)
).as_slice());
}
}
_ => {}
}
}
_ => {}
}
}
}
// Checks if a type has the #[must_root] annotation.
// Unwraps pointers as well
// TODO (#3874, sort of): unwrap other types like Vec/Option/HashMap/etc
fn lint_unrooted_ty(cx: &Context, ty: &ast::Ty, warning: &str) {
match ty.node {
ast::TyVec(ref t) | ast::TyFixedLengthVec(ref t, _) |
ast::TyPtr(ast::MutTy { ty: ref t, ..}) | ast::TyRptr(_, ast::MutTy { ty: ref t, ..}) => lint_unrooted_ty(cx, &**t, warning),
ast::TyPath(_, _, id) => {
match cx.tcx.def_map.borrow()[id].clone() {
def::DefTy(def_id, _) => {
if ty::has_attr(cx.tcx, def_id, "must_root") {
cx.span_lint(UNROOTED_MUST_ROOT, ty.span, warning);
}
}
_ => (),
}
}
_ => (),
};
}
// Determines if a block is in an unsafe context so that an unhelpful
// lint can be aborted.
fn unsafe_context(map: &ast_map::Map, id: ast::NodeId) -> bool {
match map.find(map.get_parent(id)) {
Some(ast_map::NodeImplItem(itm)) => {
match *itm {
ast::MethodImplItem(ref meth) => match meth.node {
ast::MethDecl(_, _, _, _, style, _, _, _) => match style {
ast::UnsafeFn => true,
_ => false,
},
_ => false,
},
_ => false,
}
},
Some(ast_map::NodeItem(itm)) => {
match itm.node {
ast::ItemFn(_, style, _, _, _) => match style {
ast::UnsafeFn => true,
_ => false,
},
_ => false,
}
}
_ => false // There are probably a couple of other unsafe cases we don't care to lint, those will need to be added.
}
}
impl LintPass for UnrootedPass {
fn get_lints(&self) -> LintArray {
lint_array!(UNROOTED_MUST_ROOT)
}
/// All structs containing #[must_root] types must be #[must_root] themselves
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
if cx.tcx.map.expect_item(id).attrs.iter().all(|a| !a.check_name("must_root")) {
for ref field in def.fields.iter() {
lint_unrooted_ty(cx, &*field.node.ty,
"Type must be rooted, use #[must_root] on the struct definition to propagate");
}
}
}
/// All enums containing #[must_root] types must be #[must_root] themselves
fn check_variant(&mut self, cx: &Context, var: &ast::Variant, _gen: &ast::Generics) {
let ref map = cx.tcx.map;
if map.expect_item(map.get_parent(var.node.id)).attrs.iter().all(|a| !a.check_name("must_root")) {
match var.node.kind {
ast::TupleVariantKind(ref vec) => {
for ty in vec.iter() {
lint_unrooted_ty(cx, &*ty.ty,
"Type must be rooted, use #[must_root] on the enum definition to propagate")
}
}
_ => () // Struct variants already caught by check_struct_def
}
}
}
/// Function arguments that are #[must_root] types are not allowed
fn check_fn(&mut self, cx: &Context, kind: visit::FnKind, decl: &ast::FnDecl,
block: &ast::Block, _span: codemap::Span, id: ast::NodeId) {
match kind {
visit::FkItemFn(i, _, _, _) |
visit::FkMethod(i, _, _) if i.as_str() == "new" || i.as_str() == "new_inherited" => {
return;
},
visit::FkItemFn(_, _, style, _) => match style {
ast::UnsafeFn => return,
_ => ()
},
_ => ()
}
if unsafe_context(&cx.tcx.map, id) {
return;
}
match block.rules {
ast::DefaultBlock => {
for arg in decl.inputs.iter() {
lint_unrooted_ty(cx, &*arg.ty,
"Type must be rooted")
}
}
_ => () // fn is `unsafe`
}
}
// Partially copied from rustc::middle::lint::builtin
// Catches `let` statements and assignments which store a #[must_root] value
// Expressions which return out of blocks eventually end up in a `let` or assignment
// statement or a function return (which will be caught when it is used elsewhere)
fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
match s.node {
ast::StmtDecl(_, id) |
ast::StmtExpr(_, id) |
ast::StmtSemi(_, id) if unsafe_context(&cx.tcx.map, id) => {
return
},
_ => ()
};
let expr = match s.node {
// Catch a `let` binding
ast::StmtDecl(ref decl, _) => match decl.node {
ast::DeclLocal(ref loc) => match loc.init {
Some(ref e) => &**e,
_ => return
},
_ => return
},
ast::StmtExpr(ref expr, _) => match expr.node {
// This catches deferred `let` statements
ast::ExprAssign(_, ref e) |
// Match statements allow you to bind onto the variable later in an arm
// We need not check arms individually since enum/struct fields are already
// linted in `check_struct_def` and `check_variant`
// (so there is no way of destructuring out a `#[must_root]` field)
ast::ExprMatch(ref e, _, _) |
// For loops allow you to bind a return value locally
ast::ExprForLoop(_, ref e, _, _) => &**e,
// XXXManishearth look into `if let` once it lands in our rustc
_ => return
},
_ => return
};
let t = expr_ty(cx.tcx, &*expr);
match ty::get(t).sty {
ty::ty_struct(did, _) |
ty::ty_enum(did, _) => {
if ty::has_attr(cx.tcx, did, "must_root") {
cx.span_lint(UNROOTED_MUST_ROOT, expr.span,
format!("Expression of type {} must be rooted", t.repr(cx.tcx)).as_slice());
}
}
_ => {}
}
}
}
impl LintPass for PrivatizePass {
fn get_lints(&self) -> LintArray {
lint_array!(PRIVATIZE)
}
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
if ty::has_attr(cx.tcx, ast_util::local_def(id), "privatize") {
for field in def.fields.iter() {
match field.node {
ast::StructField_ { kind: ast::NamedField(ident, visibility), .. } if visibility == Public => {
cx.span_lint(PRIVATIZE, field.span,
format!("Field {} is public where only private fields are allowed", ident.name).as_slice());
}
_ => {}
}
}
}
}
}
impl LintPass for InheritancePass {
fn get_lints(&self) -> LintArray {
lint_array!(INHERITANCE_INTEGRITY)
}
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
// Lints are run post expansion, so it's fine to use
// #[_dom_struct_marker] here without also checking for #[dom_struct]
if ty::has_attr(cx.tcx, ast_util::local_def(id), "_dom_struct_marker") {
// Find the reflector, if any
let reflector_span = def.fields.iter().enumerate()
.find(|&(ctr, f)| {
if match_lang_ty(cx, &*f.node.ty, "reflector") {
if ctr > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, f.span,
"The Reflector should be the first field of the DOM struct");
}
return true;
}
false
})
.map(|(_, f)| f.span);
// Find all #[dom_struct] fields
let dom_spans: Vec<_> = def.fields.iter().enumerate().filter_map(|(ctr, f)| {
if let ast::TyPath(_, _, ty_id) = f.node.ty.node {
if let Some(def::DefTy(def_id, _)) = cx.tcx.def_map.borrow().get(&ty_id).cloned() {
if ty::has_attr(cx.tcx, def_id, "_dom_struct_marker") {
// If the field is not the first, it's probably
// being misused (a)
if ctr > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, f.span,
"Bare DOM structs should only be used as the first field of a \
DOM struct. Consider using JS<T> instead.");
}
return Some(f.span)
}
}
}
None
}).collect();
// We should not have both a reflector and a dom struct field
if let Some(sp) = reflector_span {
if dom_spans.len() > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has both Reflector and bare DOM struct members");
if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
let sess = cx.sess();
sess.span_note(sp, "Reflector found here");
for span in dom_spans.iter() {
sess.span_note(*span, "Bare DOM struct found here");
}
}
}
// Nor should we have more than one dom struct field
} else if dom_spans.len() > 1 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has multiple DOM struct members, only one is allowed");
if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
for span in dom_spans.iter() {
cx.sess().span_note(*span, "Bare DOM struct found here");
}
}
} else if dom_spans.len() == 0 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has no reflector or parent DOM struct");
}
}
}
}
impl LintPass for StrToStringPass {
fn get_lints(&self) -> LintArray {
lint_array!(STR_TO_STRING)
}
fn check_expr(&mut self, cx: &Context, expr: &ast::Expr) {
match expr.node {
ast::ExprMethodCall(ref method, _, ref args)
if method.node.as_str() == "to_string"
&& is_str(cx, &*args[0]) => {
cx.span_lint(STR_TO_STRING, expr.span,
"str.into_string() is more efficient than str.to_string(), please use it instead");
},
_ => ()
}
fn is_str(cx: &Context, expr: &ast::Expr) -> bool {
fn walk_ty<'t>(ty: ty::t) -> ty::t {
match ty::get(ty).sty {
ty::ty_ptr(ref tm) | ty::ty_rptr(_, ref tm) => walk_ty(tm.ty),
_ => ty
}
}
match ty::get(walk_ty(expr_ty(cx.tcx, expr))).sty {
ty::ty_str => true,
_ => false
}
}
}
}

90
servo/components/plugins/lints/inheritance_integrity.rs Normal file
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@ -0,0 +1,90 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::{ast, ast_util};
use rustc::lint::{Context, LintPass, LintArray, Level};
use rustc::middle::{ty, def};
use rustc::middle::typeck::astconv::AstConv;
use utils::match_lang_ty;
declare_lint!(INHERITANCE_INTEGRITY, Deny,
"Ensures that struct fields are properly laid out for inheritance to work")
/// Lint for ensuring proper layout of DOM structs
///
/// A DOM struct must have one Reflector field or one field
/// which itself is a DOM struct (in which case it must be the first field).
pub struct InheritancePass;
impl LintPass for InheritancePass {
fn get_lints(&self) -> LintArray {
lint_array!(INHERITANCE_INTEGRITY)
}
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
// Lints are run post expansion, so it's fine to use
// #[_dom_struct_marker] here without also checking for #[dom_struct]
if ty::has_attr(cx.tcx, ast_util::local_def(id), "_dom_struct_marker") {
// Find the reflector, if any
let reflector_span = def.fields.iter().enumerate()
.find(|&(ctr, f)| {
if match_lang_ty(cx, &*f.node.ty, "reflector") {
if ctr > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, f.span,
"The Reflector should be the first field of the DOM struct");
}
return true;
}
false
})
.map(|(_, f)| f.span);
// Find all #[dom_struct] fields
let dom_spans: Vec<_> = def.fields.iter().enumerate().filter_map(|(ctr, f)| {
if let ast::TyPath(_, _, ty_id) = f.node.ty.node {
if let Some(def::DefTy(def_id, _)) = cx.tcx.def_map.borrow().get(&ty_id).cloned() {
if ty::has_attr(cx.tcx, def_id, "_dom_struct_marker") {
// If the field is not the first, it's probably
// being misused (a)
if ctr > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, f.span,
"Bare DOM structs should only be used as the first field of a \
DOM struct. Consider using JS<T> instead.");
}
return Some(f.span)
}
}
}
None
}).collect();
// We should not have both a reflector and a dom struct field
if let Some(sp) = reflector_span {
if dom_spans.len() > 0 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has both Reflector and bare DOM struct members");
if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
let sess = cx.sess();
sess.span_note(sp, "Reflector found here");
for span in dom_spans.iter() {
sess.span_note(*span, "Bare DOM struct found here");
}
}
}
// Nor should we have more than one dom struct field
} else if dom_spans.len() > 1 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has multiple DOM struct members, only one is allowed");
if cx.current_level(INHERITANCE_INTEGRITY) != Level::Allow {
for span in dom_spans.iter() {
cx.sess().span_note(*span, "Bare DOM struct found here");
}
}
} else if dom_spans.len() == 0 {
cx.span_lint(INHERITANCE_INTEGRITY, cx.tcx.map.expect_item(id).span,
"This DOM struct has no reflector or parent DOM struct");
}
}
}
}

9
servo/components/plugins/lints/mod.rs Normal file
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@ -0,0 +1,9 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
pub mod inheritance_integrity;
pub mod privatize;
pub mod str_to_string;
pub mod transmute_type;
pub mod unrooted_must_root;

38
servo/components/plugins/lints/privatize.rs Normal file
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@ -0,0 +1,38 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::{ast, ast_util};
use syntax::ast::Public;
use syntax::attr::AttrMetaMethods;
use rustc::lint::{Context, LintPass, LintArray};
use rustc::middle::ty;
use rustc::middle::typeck::astconv::AstConv;
declare_lint!(PRIVATIZE, Deny,
"Allows to enforce private fields for struct definitions")
/// Lint for keeping DOM fields private
///
/// This lint (disable with `-A privatize`/`#[allow(privatize)]`) ensures all types marked with `#[privatize]` have no private fields
pub struct PrivatizePass;
impl LintPass for PrivatizePass {
fn get_lints(&self) -> LintArray {
lint_array!(PRIVATIZE)
}
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
if ty::has_attr(cx.tcx, ast_util::local_def(id), "privatize") {
for field in def.fields.iter() {
match field.node {
ast::StructField_ { kind: ast::NamedField(ident, visibility), .. } if visibility == Public => {
cx.span_lint(PRIVATIZE, field.span,
format!("Field {} is public where only private fields are allowed", ident.name).as_slice());
}
_ => {}
}
}
}
}
}

48
servo/components/plugins/lints/str_to_string.rs Normal file
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@ -0,0 +1,48 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::ast;
use rustc::lint::{Context, LintPass, LintArray};
use rustc::middle::ty::expr_ty;
use rustc::middle::ty;
use rustc::middle::typeck::astconv::AstConv;
declare_lint!(STR_TO_STRING, Deny,
"Warn when a String could use into_string() instead of to_string()")
/// Prefer str.into_string() over str.to_string()
///
/// The latter creates a `Formatter` and is 5x slower than the former
pub struct StrToStringPass;
impl LintPass for StrToStringPass {
fn get_lints(&self) -> LintArray {
lint_array!(STR_TO_STRING)
}
fn check_expr(&mut self, cx: &Context, expr: &ast::Expr) {
match expr.node {
ast::ExprMethodCall(ref method, _, ref args)
if method.node.as_str() == "to_string"
&& is_str(cx, &*args[0]) => {
cx.span_lint(STR_TO_STRING, expr.span,
"str.into_string() is more efficient than str.to_string(), please use it instead");
},
_ => ()
}
fn is_str(cx: &Context, expr: &ast::Expr) -> bool {
fn walk_ty<'t>(ty: ty::t) -> ty::t {
match ty::get(ty).sty {
ty::ty_ptr(ref tm) | ty::ty_rptr(_, ref tm) => walk_ty(tm.ty),
_ => ty
}
}
match ty::get(walk_ty(expr_ty(cx.tcx, expr))).sty {
ty::ty_str => true,
_ => false
}
}
}
}

48
servo/components/plugins/lints/transmute_type.rs Normal file
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@ -0,0 +1,48 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::ast;
use syntax::attr::AttrMetaMethods;
use rustc::lint::{Context, LintPass, LintArray};
use rustc::middle::ty::expr_ty;
use rustc::middle::typeck::astconv::AstConv;
use rustc::util::ppaux::Repr;
declare_lint!(TRANSMUTE_TYPE_LINT, Allow,
"Warn and report types being transmuted")
/// Lint for auditing transmutes
///
/// This lint (off by default, enable with `-W transmute-type-lint`) warns about all the transmutes
/// being used, along with the types they transmute to/from.
pub struct TransmutePass;
impl LintPass for TransmutePass {
fn get_lints(&self) -> LintArray {
lint_array!(TRANSMUTE_TYPE_LINT)
}
fn check_expr(&mut self, cx: &Context, ex: &ast::Expr) {
match ex.node {
ast::ExprCall(ref expr, ref args) => {
match expr.node {
ast::ExprPath(ref path) => {
if path.segments.last()
.map_or(false, |ref segment| segment.identifier.name.as_str() == "transmute")
&& args.len() == 1 {
let tcx = cx.tcx();
cx.span_lint(TRANSMUTE_TYPE_LINT, ex.span,
format!("Transmute to {} from {} detected",
expr_ty(tcx, ex).repr(tcx),
expr_ty(tcx, &**args.get(0).unwrap()).repr(tcx)
).as_slice());
}
}
_ => {}
}
}
_ => {}
}
}
}

160
servo/components/plugins/lints/unrooted_must_root.rs Normal file
View File

@ -0,0 +1,160 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::{ast, codemap, visit};
use syntax::attr::AttrMetaMethods;
use rustc::lint::{Context, LintPass, LintArray};
use rustc::middle::ty::expr_ty;
use rustc::middle::{ty, def};
use rustc::middle::typeck::astconv::AstConv;
use rustc::util::ppaux::Repr;
use utils::unsafe_context;
declare_lint!(UNROOTED_MUST_ROOT, Deny,
"Warn and report usage of unrooted jsmanaged objects")
/// Lint for ensuring safe usage of unrooted pointers
///
/// This lint (disable with `-A unrooted-must-root`/`#[allow(unrooted_must_root)]`) ensures that `#[must_root]` values are used correctly.
/// "Incorrect" usage includes:
///
/// - Not being used in a struct/enum field which is not `#[must_root]` itself
/// - Not being used as an argument to a function (Except onces named `new` and `new_inherited`)
/// - Not being bound locally in a `let` statement, assignment, `for` loop, or `match` statement.
///
/// This helps catch most situations where pointers like `JS<T>` are used in a way that they can be invalidated by a GC pass.
pub struct UnrootedPass;
// Checks if a type has the #[must_root] annotation.
// Unwraps pointers as well
// TODO (#3874, sort of): unwrap other types like Vec/Option/HashMap/etc
fn lint_unrooted_ty(cx: &Context, ty: &ast::Ty, warning: &str) {
match ty.node {
ast::TyVec(ref t) | ast::TyFixedLengthVec(ref t, _) |
ast::TyPtr(ast::MutTy { ty: ref t, ..}) | ast::TyRptr(_, ast::MutTy { ty: ref t, ..}) => lint_unrooted_ty(cx, &**t, warning),
ast::TyPath(_, _, id) => {
match cx.tcx.def_map.borrow()[id].clone() {
def::DefTy(def_id, _) => {
if ty::has_attr(cx.tcx, def_id, "must_root") {
cx.span_lint(UNROOTED_MUST_ROOT, ty.span, warning);
}
}
_ => (),
}
}
_ => (),
};
}
impl LintPass for UnrootedPass {
fn get_lints(&self) -> LintArray {
lint_array!(UNROOTED_MUST_ROOT)
}
/// All structs containing #[must_root] types must be #[must_root] themselves
fn check_struct_def(&mut self, cx: &Context, def: &ast::StructDef, _i: ast::Ident, _gen: &ast::Generics, id: ast::NodeId) {
if cx.tcx.map.expect_item(id).attrs.iter().all(|a| !a.check_name("must_root")) {
for ref field in def.fields.iter() {
lint_unrooted_ty(cx, &*field.node.ty,
"Type must be rooted, use #[must_root] on the struct definition to propagate");
}
}
}
/// All enums containing #[must_root] types must be #[must_root] themselves
fn check_variant(&mut self, cx: &Context, var: &ast::Variant, _gen: &ast::Generics) {
let ref map = cx.tcx.map;
if map.expect_item(map.get_parent(var.node.id)).attrs.iter().all(|a| !a.check_name("must_root")) {
match var.node.kind {
ast::TupleVariantKind(ref vec) => {
for ty in vec.iter() {
lint_unrooted_ty(cx, &*ty.ty,
"Type must be rooted, use #[must_root] on the enum definition to propagate")
}
}
_ => () // Struct variants already caught by check_struct_def
}
}
}
/// Function arguments that are #[must_root] types are not allowed
fn check_fn(&mut self, cx: &Context, kind: visit::FnKind, decl: &ast::FnDecl,
block: &ast::Block, _span: codemap::Span, id: ast::NodeId) {
match kind {
visit::FkItemFn(i, _, _, _) |
visit::FkMethod(i, _, _) if i.as_str() == "new" || i.as_str() == "new_inherited" => {
return;
},
visit::FkItemFn(_, _, style, _) => match style {
ast::UnsafeFn => return,
_ => ()
},
_ => ()
}
if unsafe_context(&cx.tcx.map, id) {
return;
}
match block.rules {
ast::DefaultBlock => {
for arg in decl.inputs.iter() {
lint_unrooted_ty(cx, &*arg.ty,
"Type must be rooted")
}
}
_ => () // fn is `unsafe`
}
}
// Partially copied from rustc::middle::lint::builtin
// Catches `let` statements and assignments which store a #[must_root] value
// Expressions which return out of blocks eventually end up in a `let` or assignment
// statement or a function return (which will be caught when it is used elsewhere)
fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
match s.node {
ast::StmtDecl(_, id) |
ast::StmtExpr(_, id) |
ast::StmtSemi(_, id) if unsafe_context(&cx.tcx.map, id) => {
return
},
_ => ()
};
let expr = match s.node {
// Catch a `let` binding
ast::StmtDecl(ref decl, _) => match decl.node {
ast::DeclLocal(ref loc) => match loc.init {
Some(ref e) => &**e,
_ => return
},
_ => return
},
ast::StmtExpr(ref expr, _) => match expr.node {
// This catches deferred `let` statements
ast::ExprAssign(_, ref e) |
// Match statements allow you to bind onto the variable later in an arm
// We need not check arms individually since enum/struct fields are already
// linted in `check_struct_def` and `check_variant`
// (so there is no way of destructuring out a `#[must_root]` field)
ast::ExprMatch(ref e, _, _) |
// For loops allow you to bind a return value locally
ast::ExprForLoop(_, ref e, _, _) => &**e,
// XXXManishearth look into `if let` once it lands in our rustc
_ => return
},
_ => return
};
let t = expr_ty(cx.tcx, &*expr);
match ty::get(t).sty {
ty::ty_struct(did, _) |
ty::ty_enum(did, _) => {
if ty::has_attr(cx.tcx, did, "must_root") {
cx.span_lint(UNROOTED_MUST_ROOT, expr.span,
format!("Expression of type {} must be rooted", t.repr(cx.tcx)).as_slice());
}
}
_ => {}
}
}
}

33
servo/components/plugins/utils.rs
View File

@ -4,12 +4,14 @@
use rustc::lint::Context;
use rustc::middle::{ty, def};
use rustc::middle::typeck::astconv::AstConv;
use syntax::ptr::P;
use syntax::ast;
use syntax::{ast, ast_map};
use syntax::ast::{TyPath, Path, AngleBracketedParameters, PathSegment, Ty};
use syntax::attr::mark_used;
/// Matches a type with a provided string, and returns its type parameters if successful
///
/// Try not to use this for types defined in crates you own, use match_lang_ty instead (for lint passes)
@ -60,3 +62,32 @@ pub fn match_lang_ty(cx: &Context, ty: &Ty, value: &str) -> bool {
}
found
}
// Determines if a block is in an unsafe context so that an unhelpful
// lint can be aborted.
pub fn unsafe_context(map: &ast_map::Map, id: ast::NodeId) -> bool {
match map.find(map.get_parent(id)) {
Some(ast_map::NodeImplItem(itm)) => {
match *itm {
ast::MethodImplItem(ref meth) => match meth.node {
ast::MethDecl(_, _, _, _, style, _, _, _) => match style {
ast::UnsafeFn => true,
_ => false,
},
_ => false,
},
_ => false,
}
},
Some(ast_map::NodeItem(itm)) => {
match itm.node {
ast::ItemFn(_, style, _, _, _) => match style {
ast::UnsafeFn => true,
_ => false,
},
_ => false,
}
}
_ => false // There are probably a couple of other unsafe cases we don't care to lint, those will need to be added.
}
}