881 lines
36 KiB
Rust
881 lines
36 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![allow(non_snake_case)]
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use rustc::hir::Node;
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use rustc::ty::subst::Substs;
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use rustc::ty::{self, AdtKind, ParamEnv, Ty, TyCtxt};
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use rustc::ty::layout::{self, IntegerExt, LayoutOf, VariantIdx};
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use rustc_data_structures::indexed_vec::Idx;
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use util::nodemap::FxHashSet;
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use lint::{LateContext, LintContext, LintArray};
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use lint::{LintPass, LateLintPass};
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use std::cmp;
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use std::{i8, i16, i32, i64, u8, u16, u32, u64, f32, f64};
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use syntax::{ast, attr};
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use syntax::errors::Applicability;
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use rustc_target::spec::abi::Abi;
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use syntax::edition::Edition;
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use syntax_pos::Span;
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use syntax::source_map;
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use rustc::hir;
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declare_lint! {
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UNUSED_COMPARISONS,
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Warn,
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"comparisons made useless by limits of the types involved"
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}
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declare_lint! {
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OVERFLOWING_LITERALS,
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Warn,
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"literal out of range for its type",
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Edition::Edition2018 => Deny
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}
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declare_lint! {
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VARIANT_SIZE_DIFFERENCES,
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Allow,
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"detects enums with widely varying variant sizes"
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}
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#[derive(Copy, Clone)]
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pub struct TypeLimits {
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/// Id of the last visited negated expression
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negated_expr_id: ast::NodeId,
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}
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impl TypeLimits {
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pub fn new() -> TypeLimits {
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TypeLimits { negated_expr_id: ast::DUMMY_NODE_ID }
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}
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}
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impl LintPass for TypeLimits {
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fn get_lints(&self) -> LintArray {
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lint_array!(UNUSED_COMPARISONS,
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OVERFLOWING_LITERALS)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx hir::Expr) {
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match e.node {
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hir::ExprKind::Unary(hir::UnNeg, ref expr) => {
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// propagate negation, if the negation itself isn't negated
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if self.negated_expr_id != e.id {
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self.negated_expr_id = expr.id;
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}
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}
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hir::ExprKind::Binary(binop, ref l, ref r) => {
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if is_comparison(binop) && !check_limits(cx, binop, &l, &r) {
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cx.span_lint(UNUSED_COMPARISONS,
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e.span,
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"comparison is useless due to type limits");
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}
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}
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hir::ExprKind::Lit(ref lit) => {
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match cx.tables.node_id_to_type(e.hir_id).sty {
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ty::Int(t) => {
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match lit.node {
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ast::LitKind::Int(v, ast::LitIntType::Signed(_)) |
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ast::LitKind::Int(v, ast::LitIntType::Unsuffixed) => {
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let int_type = if let ast::IntTy::Isize = t {
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cx.sess().target.isize_ty
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} else {
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t
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};
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let (_, max) = int_ty_range(int_type);
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let max = max as u128;
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let negative = self.negated_expr_id == e.id;
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// Detect literal value out of range [min, max] inclusive
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// avoiding use of -min to prevent overflow/panic
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if (negative && v > max + 1) || (!negative && v > max) {
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if let Some(repr_str) = get_bin_hex_repr(cx, lit) {
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report_bin_hex_error(
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cx,
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e,
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ty::Int(t),
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repr_str,
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v,
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negative,
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);
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return;
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}
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cx.span_lint(
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OVERFLOWING_LITERALS,
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e.span,
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&format!("literal out of range for {:?}", t),
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);
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return;
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}
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}
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_ => bug!(),
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};
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}
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ty::Uint(t) => {
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let uint_type = if let ast::UintTy::Usize = t {
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cx.sess().target.usize_ty
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} else {
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t
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};
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let (min, max) = uint_ty_range(uint_type);
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let lit_val: u128 = match lit.node {
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// _v is u8, within range by definition
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ast::LitKind::Byte(_v) => return,
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ast::LitKind::Int(v, _) => v,
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_ => bug!(),
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};
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if lit_val < min || lit_val > max {
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let parent_id = cx.tcx.hir.get_parent_node(e.id);
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if let Node::Expr(parent_expr) = cx.tcx.hir.get(parent_id) {
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if let hir::ExprKind::Cast(..) = parent_expr.node {
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if let ty::Char = cx.tables.expr_ty(parent_expr).sty {
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let mut err = cx.struct_span_lint(
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OVERFLOWING_LITERALS,
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parent_expr.span,
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"only u8 can be cast into char");
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err.span_suggestion_with_applicability(
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parent_expr.span,
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&"use a char literal instead",
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format!("'\\u{{{:X}}}'", lit_val),
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Applicability::MachineApplicable
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);
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err.emit();
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return
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}
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}
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}
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if let Some(repr_str) = get_bin_hex_repr(cx, lit) {
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report_bin_hex_error(
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cx,
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e,
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ty::Uint(t),
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repr_str,
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lit_val,
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false,
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);
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return;
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}
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cx.span_lint(
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OVERFLOWING_LITERALS,
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e.span,
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&format!("literal out of range for {:?}", t),
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);
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}
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}
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ty::Float(t) => {
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let is_infinite = match lit.node {
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ast::LitKind::Float(v, _) |
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ast::LitKind::FloatUnsuffixed(v) => {
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match t {
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ast::FloatTy::F32 => v.as_str().parse().map(f32::is_infinite),
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ast::FloatTy::F64 => v.as_str().parse().map(f64::is_infinite),
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}
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}
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_ => bug!(),
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};
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if is_infinite == Ok(true) {
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cx.span_lint(OVERFLOWING_LITERALS,
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e.span,
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&format!("literal out of range for {:?}", t));
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}
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}
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_ => (),
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};
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}
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_ => (),
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};
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fn is_valid<T: cmp::PartialOrd>(binop: hir::BinOp, v: T, min: T, max: T) -> bool {
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match binop.node {
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hir::BinOpKind::Lt => v > min && v <= max,
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hir::BinOpKind::Le => v >= min && v < max,
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hir::BinOpKind::Gt => v >= min && v < max,
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hir::BinOpKind::Ge => v > min && v <= max,
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hir::BinOpKind::Eq | hir::BinOpKind::Ne => v >= min && v <= max,
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_ => bug!(),
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}
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}
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fn rev_binop(binop: hir::BinOp) -> hir::BinOp {
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source_map::respan(binop.span,
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match binop.node {
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hir::BinOpKind::Lt => hir::BinOpKind::Gt,
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hir::BinOpKind::Le => hir::BinOpKind::Ge,
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hir::BinOpKind::Gt => hir::BinOpKind::Lt,
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hir::BinOpKind::Ge => hir::BinOpKind::Le,
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_ => return binop,
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})
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}
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// for isize & usize, be conservative with the warnings, so that the
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// warnings are consistent between 32- and 64-bit platforms
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fn int_ty_range(int_ty: ast::IntTy) -> (i128, i128) {
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match int_ty {
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ast::IntTy::Isize => (i64::min_value() as i128, i64::max_value() as i128),
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ast::IntTy::I8 => (i8::min_value() as i64 as i128, i8::max_value() as i128),
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ast::IntTy::I16 => (i16::min_value() as i64 as i128, i16::max_value() as i128),
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ast::IntTy::I32 => (i32::min_value() as i64 as i128, i32::max_value() as i128),
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ast::IntTy::I64 => (i64::min_value() as i128, i64::max_value() as i128),
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ast::IntTy::I128 =>(i128::min_value() as i128, i128::max_value()),
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}
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}
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fn uint_ty_range(uint_ty: ast::UintTy) -> (u128, u128) {
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match uint_ty {
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ast::UintTy::Usize => (u64::min_value() as u128, u64::max_value() as u128),
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ast::UintTy::U8 => (u8::min_value() as u128, u8::max_value() as u128),
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ast::UintTy::U16 => (u16::min_value() as u128, u16::max_value() as u128),
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ast::UintTy::U32 => (u32::min_value() as u128, u32::max_value() as u128),
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ast::UintTy::U64 => (u64::min_value() as u128, u64::max_value() as u128),
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ast::UintTy::U128 => (u128::min_value(), u128::max_value()),
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}
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}
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fn check_limits(cx: &LateContext,
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binop: hir::BinOp,
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l: &hir::Expr,
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r: &hir::Expr)
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-> bool {
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let (lit, expr, swap) = match (&l.node, &r.node) {
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(&hir::ExprKind::Lit(_), _) => (l, r, true),
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(_, &hir::ExprKind::Lit(_)) => (r, l, false),
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_ => return true,
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};
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// Normalize the binop so that the literal is always on the RHS in
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// the comparison
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let norm_binop = if swap { rev_binop(binop) } else { binop };
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match cx.tables.node_id_to_type(expr.hir_id).sty {
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ty::Int(int_ty) => {
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let (min, max) = int_ty_range(int_ty);
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let lit_val: i128 = match lit.node {
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hir::ExprKind::Lit(ref li) => {
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match li.node {
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ast::LitKind::Int(v, ast::LitIntType::Signed(_)) |
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ast::LitKind::Int(v, ast::LitIntType::Unsuffixed) => v as i128,
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_ => return true
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}
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},
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_ => bug!()
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};
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is_valid(norm_binop, lit_val, min, max)
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}
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ty::Uint(uint_ty) => {
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let (min, max) :(u128, u128) = uint_ty_range(uint_ty);
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let lit_val: u128 = match lit.node {
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hir::ExprKind::Lit(ref li) => {
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match li.node {
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ast::LitKind::Int(v, _) => v,
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_ => return true
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}
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},
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_ => bug!()
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};
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is_valid(norm_binop, lit_val, min, max)
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}
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_ => true,
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}
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}
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fn is_comparison(binop: hir::BinOp) -> bool {
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match binop.node {
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hir::BinOpKind::Eq |
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hir::BinOpKind::Lt |
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hir::BinOpKind::Le |
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hir::BinOpKind::Ne |
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hir::BinOpKind::Ge |
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hir::BinOpKind::Gt => true,
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_ => false,
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}
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}
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fn get_bin_hex_repr(cx: &LateContext, lit: &ast::Lit) -> Option<String> {
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let src = cx.sess().source_map().span_to_snippet(lit.span).ok()?;
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let firstch = src.chars().next()?;
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if firstch == '0' {
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match src.chars().nth(1) {
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Some('x') | Some('b') => return Some(src),
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_ => return None,
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}
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}
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None
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}
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// This function finds the next fitting type and generates a suggestion string.
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// It searches for fitting types in the following way (`X < Y`):
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// - `iX`: if literal fits in `uX` => `uX`, else => `iY`
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// - `-iX` => `iY`
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// - `uX` => `uY`
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//
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// No suggestion for: `isize`, `usize`.
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fn get_type_suggestion<'a>(
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t: &ty::TyKind,
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val: u128,
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negative: bool,
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) -> Option<String> {
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use syntax::ast::IntTy::*;
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use syntax::ast::UintTy::*;
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macro_rules! find_fit {
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($ty:expr, $val:expr, $negative:expr,
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$($type:ident => [$($utypes:expr),*] => [$($itypes:expr),*]),+) => {
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{
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let _neg = if negative { 1 } else { 0 };
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match $ty {
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$($type => {
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$(if !negative && val <= uint_ty_range($utypes).1 {
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return Some(format!("{:?}", $utypes))
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})*
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$(if val <= int_ty_range($itypes).1 as u128 + _neg {
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return Some(format!("{:?}", $itypes))
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})*
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None
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},)*
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_ => None
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}
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}
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}
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}
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match t {
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&ty::Int(i) => find_fit!(i, val, negative,
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I8 => [U8] => [I16, I32, I64, I128],
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I16 => [U16] => [I32, I64, I128],
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I32 => [U32] => [I64, I128],
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I64 => [U64] => [I128],
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I128 => [U128] => []),
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&ty::Uint(u) => find_fit!(u, val, negative,
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U8 => [U8, U16, U32, U64, U128] => [],
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U16 => [U16, U32, U64, U128] => [],
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U32 => [U32, U64, U128] => [],
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U64 => [U64, U128] => [],
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U128 => [U128] => []),
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_ => None,
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}
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}
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fn report_bin_hex_error(
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cx: &LateContext,
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expr: &hir::Expr,
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ty: ty::TyKind,
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repr_str: String,
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val: u128,
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negative: bool,
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) {
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let (t, actually) = match ty {
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ty::Int(t) => {
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let ity = attr::IntType::SignedInt(t);
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let bits = layout::Integer::from_attr(&cx.tcx, ity).size().bits();
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let actually = (val << (128 - bits)) as i128 >> (128 - bits);
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(format!("{:?}", t), actually.to_string())
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}
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ty::Uint(t) => {
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let ity = attr::IntType::UnsignedInt(t);
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let bits = layout::Integer::from_attr(&cx.tcx, ity).size().bits();
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let actually = (val << (128 - bits)) >> (128 - bits);
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(format!("{:?}", t), actually.to_string())
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}
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_ => bug!(),
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};
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let mut err = cx.struct_span_lint(
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OVERFLOWING_LITERALS,
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expr.span,
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&format!("literal out of range for {}", t),
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);
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err.note(&format!(
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"the literal `{}` (decimal `{}`) does not fit into \
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an `{}` and will become `{}{}`",
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repr_str, val, t, actually, t
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));
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if let Some(sugg_ty) =
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get_type_suggestion(&cx.tables.node_id_to_type(expr.hir_id).sty, val, negative)
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{
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if let Some(pos) = repr_str.chars().position(|c| c == 'i' || c == 'u') {
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let (sans_suffix, _) = repr_str.split_at(pos);
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err.span_suggestion_with_applicability(
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expr.span,
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&format!("consider using `{}` instead", sugg_ty),
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format!("{}{}", sans_suffix, sugg_ty),
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Applicability::MachineApplicable
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);
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} else {
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err.help(&format!("consider using `{}` instead", sugg_ty));
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}
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}
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err.emit();
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}
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}
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}
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declare_lint! {
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IMPROPER_CTYPES,
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Warn,
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"proper use of libc types in foreign modules"
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}
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struct ImproperCTypesVisitor<'a, 'tcx: 'a> {
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cx: &'a LateContext<'a, 'tcx>,
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}
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enum FfiResult<'tcx> {
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FfiSafe,
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FfiPhantom(Ty<'tcx>),
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FfiUnsafe {
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ty: Ty<'tcx>,
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reason: &'static str,
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help: Option<&'static str>,
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},
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}
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/// Check if this enum can be safely exported based on the
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/// "nullable pointer optimization". Currently restricted
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/// to function pointers and references, but could be
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/// expanded to cover NonZero raw pointers and newtypes.
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/// FIXME: This duplicates code in codegen.
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fn is_repr_nullable_ptr<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
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def: &'tcx ty::AdtDef,
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substs: &Substs<'tcx>)
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-> bool {
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if def.variants.len() == 2 {
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let data_idx;
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let zero = VariantIdx::new(0);
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let one = VariantIdx::new(1);
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if def.variants[zero].fields.is_empty() {
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data_idx = one;
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} else if def.variants[one].fields.is_empty() {
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data_idx = zero;
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} else {
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return false;
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}
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if def.variants[data_idx].fields.len() == 1 {
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match def.variants[data_idx].fields[0].ty(tcx, substs).sty {
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ty::FnPtr(_) => {
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return true;
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}
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|
ty::Ref(..) => {
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return true;
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}
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_ => {}
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}
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}
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}
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false
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}
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|
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impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
|
|
/// Check if the given type is "ffi-safe" (has a stable, well-defined
|
|
/// representation which can be exported to C code).
|
|
fn check_type_for_ffi(&self,
|
|
cache: &mut FxHashSet<Ty<'tcx>>,
|
|
ty: Ty<'tcx>) -> FfiResult<'tcx> {
|
|
use self::FfiResult::*;
|
|
|
|
let cx = self.cx.tcx;
|
|
|
|
// Protect against infinite recursion, for example
|
|
// `struct S(*mut S);`.
|
|
// FIXME: A recursion limit is necessary as well, for irregular
|
|
// recursive types.
|
|
if !cache.insert(ty) {
|
|
return FfiSafe;
|
|
}
|
|
|
|
match ty.sty {
|
|
ty::Adt(def, substs) => {
|
|
if def.is_phantom_data() {
|
|
return FfiPhantom(ty);
|
|
}
|
|
match def.adt_kind() {
|
|
AdtKind::Struct => {
|
|
if !def.repr.c() && !def.repr.transparent() {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "this struct has unspecified layout",
|
|
help: Some("consider adding a #[repr(C)] or #[repr(transparent)] \
|
|
attribute to this struct"),
|
|
};
|
|
}
|
|
|
|
if def.non_enum_variant().fields.is_empty() {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "this struct has no fields",
|
|
help: Some("consider adding a member to this struct"),
|
|
};
|
|
}
|
|
|
|
// We can't completely trust repr(C) and repr(transparent) markings;
|
|
// make sure the fields are actually safe.
|
|
let mut all_phantom = true;
|
|
for field in &def.non_enum_variant().fields {
|
|
let field_ty = cx.normalize_erasing_regions(
|
|
ParamEnv::reveal_all(),
|
|
field.ty(cx, substs),
|
|
);
|
|
// repr(transparent) types are allowed to have arbitrary ZSTs, not just
|
|
// PhantomData -- skip checking all ZST fields
|
|
if def.repr.transparent() {
|
|
let is_zst = cx
|
|
.layout_of(cx.param_env(field.did).and(field_ty))
|
|
.map(|layout| layout.is_zst())
|
|
.unwrap_or(false);
|
|
if is_zst {
|
|
continue;
|
|
}
|
|
}
|
|
let r = self.check_type_for_ffi(cache, field_ty);
|
|
match r {
|
|
FfiSafe => {
|
|
all_phantom = false;
|
|
}
|
|
FfiPhantom(..) => {}
|
|
FfiUnsafe { .. } => {
|
|
return r;
|
|
}
|
|
}
|
|
}
|
|
|
|
if all_phantom { FfiPhantom(ty) } else { FfiSafe }
|
|
}
|
|
AdtKind::Union => {
|
|
if !def.repr.c() {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "this union has unspecified layout",
|
|
help: Some("consider adding a #[repr(C)] attribute to this union"),
|
|
};
|
|
}
|
|
|
|
if def.non_enum_variant().fields.is_empty() {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "this union has no fields",
|
|
help: Some("consider adding a field to this union"),
|
|
};
|
|
}
|
|
|
|
let mut all_phantom = true;
|
|
for field in &def.non_enum_variant().fields {
|
|
let field_ty = cx.normalize_erasing_regions(
|
|
ParamEnv::reveal_all(),
|
|
field.ty(cx, substs),
|
|
);
|
|
let r = self.check_type_for_ffi(cache, field_ty);
|
|
match r {
|
|
FfiSafe => {
|
|
all_phantom = false;
|
|
}
|
|
FfiPhantom(..) => {}
|
|
FfiUnsafe { .. } => {
|
|
return r;
|
|
}
|
|
}
|
|
}
|
|
|
|
if all_phantom { FfiPhantom(ty) } else { FfiSafe }
|
|
}
|
|
AdtKind::Enum => {
|
|
if def.variants.is_empty() {
|
|
// Empty enums are okay... although sort of useless.
|
|
return FfiSafe;
|
|
}
|
|
|
|
// Check for a repr() attribute to specify the size of the
|
|
// discriminant.
|
|
if !def.repr.c() && def.repr.int.is_none() {
|
|
// Special-case types like `Option<extern fn()>`.
|
|
if !is_repr_nullable_ptr(cx, def, substs) {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "enum has no representation hint",
|
|
help: Some("consider adding a #[repr(...)] attribute \
|
|
to this enum"),
|
|
};
|
|
}
|
|
}
|
|
|
|
// Check the contained variants.
|
|
for variant in &def.variants {
|
|
for field in &variant.fields {
|
|
let arg = cx.normalize_erasing_regions(
|
|
ParamEnv::reveal_all(),
|
|
field.ty(cx, substs),
|
|
);
|
|
let r = self.check_type_for_ffi(cache, arg);
|
|
match r {
|
|
FfiSafe => {}
|
|
FfiUnsafe { .. } => {
|
|
return r;
|
|
}
|
|
FfiPhantom(..) => {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "this enum contains a PhantomData field",
|
|
help: None,
|
|
};
|
|
}
|
|
}
|
|
}
|
|
}
|
|
FfiSafe
|
|
}
|
|
}
|
|
}
|
|
|
|
ty::Char => FfiUnsafe {
|
|
ty: ty,
|
|
reason: "the `char` type has no C equivalent",
|
|
help: Some("consider using `u32` or `libc::wchar_t` instead"),
|
|
},
|
|
|
|
ty::Int(ast::IntTy::I128) | ty::Uint(ast::UintTy::U128) => FfiUnsafe {
|
|
ty: ty,
|
|
reason: "128-bit integers don't currently have a known stable ABI",
|
|
help: None,
|
|
},
|
|
|
|
// Primitive types with a stable representation.
|
|
ty::Bool | ty::Int(..) | ty::Uint(..) | ty::Float(..) | ty::Never => FfiSafe,
|
|
|
|
ty::Slice(_) => FfiUnsafe {
|
|
ty: ty,
|
|
reason: "slices have no C equivalent",
|
|
help: Some("consider using a raw pointer instead"),
|
|
},
|
|
|
|
ty::Dynamic(..) => FfiUnsafe {
|
|
ty: ty,
|
|
reason: "trait objects have no C equivalent",
|
|
help: None,
|
|
},
|
|
|
|
ty::Str => FfiUnsafe {
|
|
ty: ty,
|
|
reason: "string slices have no C equivalent",
|
|
help: Some("consider using `*const u8` and a length instead"),
|
|
},
|
|
|
|
ty::Tuple(..) => FfiUnsafe {
|
|
ty: ty,
|
|
reason: "tuples have unspecified layout",
|
|
help: Some("consider using a struct instead"),
|
|
},
|
|
|
|
ty::RawPtr(ty::TypeAndMut { ty, .. }) |
|
|
ty::Ref(_, ty, _) => self.check_type_for_ffi(cache, ty),
|
|
|
|
ty::Array(ty, _) => self.check_type_for_ffi(cache, ty),
|
|
|
|
ty::FnPtr(sig) => {
|
|
match sig.abi() {
|
|
Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic | Abi::RustCall => {
|
|
return FfiUnsafe {
|
|
ty: ty,
|
|
reason: "this function pointer has Rust-specific calling convention",
|
|
help: Some("consider using an `extern fn(...) -> ...` \
|
|
function pointer instead"),
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
let sig = cx.erase_late_bound_regions(&sig);
|
|
if !sig.output().is_unit() {
|
|
let r = self.check_type_for_ffi(cache, sig.output());
|
|
match r {
|
|
FfiSafe => {}
|
|
_ => {
|
|
return r;
|
|
}
|
|
}
|
|
}
|
|
for arg in sig.inputs() {
|
|
let r = self.check_type_for_ffi(cache, arg);
|
|
match r {
|
|
FfiSafe => {}
|
|
_ => {
|
|
return r;
|
|
}
|
|
}
|
|
}
|
|
FfiSafe
|
|
}
|
|
|
|
ty::Foreign(..) => FfiSafe,
|
|
|
|
ty::Param(..) |
|
|
ty::Infer(..) |
|
|
ty::Bound(..) |
|
|
ty::Error |
|
|
ty::Closure(..) |
|
|
ty::Generator(..) |
|
|
ty::GeneratorWitness(..) |
|
|
ty::UnnormalizedProjection(..) |
|
|
ty::Projection(..) |
|
|
ty::Opaque(..) |
|
|
ty::FnDef(..) => bug!("Unexpected type in foreign function"),
|
|
}
|
|
}
|
|
|
|
fn check_type_for_ffi_and_report_errors(&mut self, sp: Span, ty: Ty<'tcx>) {
|
|
// it is only OK to use this function because extern fns cannot have
|
|
// any generic types right now:
|
|
let ty = self.cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), ty);
|
|
|
|
match self.check_type_for_ffi(&mut FxHashSet::default(), ty) {
|
|
FfiResult::FfiSafe => {}
|
|
FfiResult::FfiPhantom(ty) => {
|
|
self.cx.span_lint(IMPROPER_CTYPES,
|
|
sp,
|
|
&format!("`extern` block uses type `{}` which is not FFI-safe: \
|
|
composed only of PhantomData", ty));
|
|
}
|
|
FfiResult::FfiUnsafe { ty: unsafe_ty, reason, help } => {
|
|
let msg = format!("`extern` block uses type `{}` which is not FFI-safe: {}",
|
|
unsafe_ty, reason);
|
|
let mut diag = self.cx.struct_span_lint(IMPROPER_CTYPES, sp, &msg);
|
|
if let Some(s) = help {
|
|
diag.help(s);
|
|
}
|
|
if let ty::Adt(def, _) = unsafe_ty.sty {
|
|
if let Some(sp) = self.cx.tcx.hir.span_if_local(def.did) {
|
|
diag.span_note(sp, "type defined here");
|
|
}
|
|
}
|
|
diag.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_foreign_fn(&mut self, id: ast::NodeId, decl: &hir::FnDecl) {
|
|
let def_id = self.cx.tcx.hir.local_def_id(id);
|
|
let sig = self.cx.tcx.fn_sig(def_id);
|
|
let sig = self.cx.tcx.erase_late_bound_regions(&sig);
|
|
|
|
for (input_ty, input_hir) in sig.inputs().iter().zip(&decl.inputs) {
|
|
self.check_type_for_ffi_and_report_errors(input_hir.span, input_ty);
|
|
}
|
|
|
|
if let hir::Return(ref ret_hir) = decl.output {
|
|
let ret_ty = sig.output();
|
|
if !ret_ty.is_unit() {
|
|
self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_foreign_static(&mut self, id: ast::NodeId, span: Span) {
|
|
let def_id = self.cx.tcx.hir.local_def_id(id);
|
|
let ty = self.cx.tcx.type_of(def_id);
|
|
self.check_type_for_ffi_and_report_errors(span, ty);
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct ImproperCTypes;
|
|
|
|
impl LintPass for ImproperCTypes {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(IMPROPER_CTYPES)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImproperCTypes {
|
|
fn check_foreign_item(&mut self, cx: &LateContext, it: &hir::ForeignItem) {
|
|
let mut vis = ImproperCTypesVisitor { cx };
|
|
let abi = cx.tcx.hir.get_foreign_abi(it.id);
|
|
if abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic {
|
|
match it.node {
|
|
hir::ForeignItemKind::Fn(ref decl, _, _) => {
|
|
vis.check_foreign_fn(it.id, decl);
|
|
}
|
|
hir::ForeignItemKind::Static(ref ty, _) => {
|
|
vis.check_foreign_static(it.id, ty.span);
|
|
}
|
|
hir::ForeignItemKind::Type => ()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub struct VariantSizeDifferences;
|
|
|
|
impl LintPass for VariantSizeDifferences {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(VARIANT_SIZE_DIFFERENCES)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for VariantSizeDifferences {
|
|
fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
|
|
if let hir::ItemKind::Enum(ref enum_definition, _) = it.node {
|
|
let item_def_id = cx.tcx.hir.local_def_id(it.id);
|
|
let t = cx.tcx.type_of(item_def_id);
|
|
let ty = cx.tcx.erase_regions(&t);
|
|
match cx.layout_of(ty) {
|
|
Ok(layout) => {
|
|
let variants = &layout.variants;
|
|
if let layout::Variants::Tagged { ref variants, ref tag, .. } = variants {
|
|
let discr_size = tag.value.size(&cx.tcx).bytes();
|
|
|
|
debug!("enum `{}` is {} bytes large with layout:\n{:#?}",
|
|
t, layout.size.bytes(), layout);
|
|
|
|
let (largest, slargest, largest_index) = enum_definition.variants
|
|
.iter()
|
|
.zip(variants)
|
|
.map(|(variant, variant_layout)| {
|
|
// Subtract the size of the enum discriminant.
|
|
let bytes = variant_layout.size.bytes().saturating_sub(discr_size);
|
|
|
|
debug!("- variant `{}` is {} bytes large",
|
|
variant.node.name,
|
|
bytes);
|
|
bytes
|
|
})
|
|
.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 {
|
|
cx.span_lint(VARIANT_SIZE_DIFFERENCES,
|
|
enum_definition.variants[largest_index].span,
|
|
&format!("enum variant is more than three times \
|
|
larger ({} bytes) than the next largest",
|
|
largest));
|
|
}
|
|
}
|
|
}
|
|
Err(ty::layout::LayoutError::Unknown(_)) => return,
|
|
Err(err @ ty::layout::LayoutError::SizeOverflow(_)) => {
|
|
bug!("failed to get layout for `{}`: {}", t, err);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|