diff options
Diffstat (limited to 'compiler/rustc_lint/src')
| -rw-r--r-- | compiler/rustc_lint/src/builtin.rs | 4 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/context.rs | 23 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/dangling.rs | 152 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/default_could_be_derived.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/foreign_modules.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/lints.rs | 16 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/nonstandard_style.rs | 4 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/pass_by_value.rs | 4 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/types/literal.rs | 8 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/unused.rs | 4 |
10 files changed, 186 insertions, 35 deletions
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs index 152971c4ed6..c893b723375 100644 --- a/compiler/rustc_lint/src/builtin.rs +++ b/compiler/rustc_lint/src/builtin.rs @@ -21,14 +21,14 @@ use rustc_ast::tokenstream::{TokenStream, TokenTree}; use rustc_ast::visit::{FnCtxt, FnKind}; use rustc_ast::{self as ast, *}; use rustc_ast_pretty::pprust::expr_to_string; -use rustc_attr_data_structures::{AttributeKind, find_attr}; use rustc_errors::{Applicability, LintDiagnostic}; use rustc_feature::GateIssue; use rustc_hir as hir; +use rustc_hir::attrs::AttributeKind; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::{CRATE_DEF_ID, DefId, LocalDefId}; use rustc_hir::intravisit::FnKind as HirFnKind; -use rustc_hir::{Body, FnDecl, PatKind, PredicateOrigin}; +use rustc_hir::{Body, FnDecl, PatKind, PredicateOrigin, find_attr}; use rustc_middle::bug; use rustc_middle::lint::LevelAndSource; use rustc_middle::ty::layout::LayoutOf; diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs index b694d3dd49b..11181d10af5 100644 --- a/compiler/rustc_lint/src/context.rs +++ b/compiler/rustc_lint/src/context.rs @@ -756,22 +756,22 @@ impl<'tcx> LateContext<'tcx> { } fn print_region(&mut self, _region: ty::Region<'_>) -> Result<(), PrintError> { - Ok(()) + unreachable!(); // because `path_generic_args` ignores the `GenericArgs` } fn print_type(&mut self, _ty: Ty<'tcx>) -> Result<(), PrintError> { - Ok(()) + unreachable!(); // because `path_generic_args` ignores the `GenericArgs` } fn print_dyn_existential( &mut self, _predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, ) -> Result<(), PrintError> { - Ok(()) + unreachable!(); // because `path_generic_args` ignores the `GenericArgs` } fn print_const(&mut self, _ct: ty::Const<'tcx>) -> Result<(), PrintError> { - Ok(()) + unreachable!(); // because `path_generic_args` ignores the `GenericArgs` } fn path_crate(&mut self, cnum: CrateNum) -> Result<(), PrintError> { @@ -784,10 +784,10 @@ impl<'tcx> LateContext<'tcx> { self_ty: Ty<'tcx>, trait_ref: Option<ty::TraitRef<'tcx>>, ) -> Result<(), PrintError> { - if trait_ref.is_none() { - if let ty::Adt(def, args) = self_ty.kind() { - return self.print_def_path(def.did(), args); - } + if trait_ref.is_none() + && let ty::Adt(def, args) = self_ty.kind() + { + return self.print_def_path(def.did(), args); } // This shouldn't ever be needed, but just in case: @@ -803,7 +803,6 @@ impl<'tcx> LateContext<'tcx> { fn path_append_impl( &mut self, print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>, - _disambiguated_data: &DisambiguatedDefPathData, self_ty: Ty<'tcx>, trait_ref: Option<ty::TraitRef<'tcx>>, ) -> Result<(), PrintError> { @@ -854,9 +853,9 @@ impl<'tcx> LateContext<'tcx> { } } - let mut printer = AbsolutePathPrinter { tcx: self.tcx, path: vec![] }; - printer.print_def_path(def_id, &[]).unwrap(); - printer.path + let mut p = AbsolutePathPrinter { tcx: self.tcx, path: vec![] }; + p.print_def_path(def_id, &[]).unwrap(); + p.path } /// Returns the associated type `name` for `self_ty` as an implementation of `trait_id`. diff --git a/compiler/rustc_lint/src/dangling.rs b/compiler/rustc_lint/src/dangling.rs index c737919db9c..af4457f4314 100644 --- a/compiler/rustc_lint/src/dangling.rs +++ b/compiler/rustc_lint/src/dangling.rs @@ -1,13 +1,14 @@ use rustc_ast::visit::{visit_opt, walk_list}; -use rustc_attr_data_structures::{AttributeKind, find_attr}; +use rustc_hir::attrs::AttributeKind; +use rustc_hir::def::Res; use rustc_hir::def_id::LocalDefId; use rustc_hir::intravisit::{FnKind, Visitor, walk_expr}; -use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, LangItem}; -use rustc_middle::ty::{Ty, TyCtxt}; +use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, FnRetTy, LangItem, TyKind, find_attr}; +use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_session::{declare_lint, impl_lint_pass}; use rustc_span::{Span, sym}; -use crate::lints::DanglingPointersFromTemporaries; +use crate::lints::{DanglingPointersFromLocals, DanglingPointersFromTemporaries}; use crate::{LateContext, LateLintPass}; declare_lint! { @@ -42,6 +43,36 @@ declare_lint! { "detects getting a pointer from a temporary" } +declare_lint! { + /// The `dangling_pointers_from_locals` lint detects getting a pointer to data + /// of a local that will be dropped at the end of the function. + /// + /// ### Example + /// + /// ```rust + /// fn f() -> *const u8 { + /// let x = 0; + /// &x // returns a dangling ptr to `x` + /// } + /// ``` + /// + /// {{produces}} + /// + /// ### Explanation + /// + /// Returning a pointer from a local value will not prolong its lifetime, + /// which means that the value can be dropped and the allocation freed + /// while the pointer still exists, making the pointer dangling. + /// This is not an error (as far as the type system is concerned) + /// but probably is not what the user intended either. + /// + /// If you need stronger guarantees, consider using references instead, + /// as they are statically verified by the borrow-checker to never dangle. + pub DANGLING_POINTERS_FROM_LOCALS, + Warn, + "detects returning a pointer from a local variable" +} + /// FIXME: false negatives (i.e. the lint is not emitted when it should be) /// 1. Ways to get a temporary that are not recognized: /// - `owning_temporary.field` @@ -53,20 +84,123 @@ declare_lint! { #[derive(Clone, Copy, Default)] pub(crate) struct DanglingPointers; -impl_lint_pass!(DanglingPointers => [DANGLING_POINTERS_FROM_TEMPORARIES]); +impl_lint_pass!(DanglingPointers => [DANGLING_POINTERS_FROM_TEMPORARIES, DANGLING_POINTERS_FROM_LOCALS]); // This skips over const blocks, but they cannot use or return a dangling pointer anyways. impl<'tcx> LateLintPass<'tcx> for DanglingPointers { fn check_fn( &mut self, cx: &LateContext<'tcx>, - _: FnKind<'tcx>, - _: &'tcx FnDecl<'tcx>, + fn_kind: FnKind<'tcx>, + fn_decl: &'tcx FnDecl<'tcx>, body: &'tcx Body<'tcx>, _: Span, - _: LocalDefId, + def_id: LocalDefId, ) { - DanglingPointerSearcher { cx, inside_call_args: false }.visit_body(body) + DanglingPointerSearcher { cx, inside_call_args: false }.visit_body(body); + + if let FnRetTy::Return(ret_ty) = &fn_decl.output + && let TyKind::Ptr(_) = ret_ty.kind + { + // get the return type of the function or closure + let ty = match cx.tcx.type_of(def_id).instantiate_identity().kind() { + ty::FnDef(..) => cx.tcx.fn_sig(def_id).instantiate_identity(), + ty::Closure(_, args) => args.as_closure().sig(), + _ => return, + }; + let ty = ty.output(); + + // this type is only used for layout computation and pretty-printing, neither of them rely on regions + let ty = cx.tcx.instantiate_bound_regions_with_erased(ty); + + // verify that we have a pointer type + let inner_ty = match ty.kind() { + ty::RawPtr(inner_ty, _) => *inner_ty, + _ => return, + }; + + if cx + .tcx + .layout_of(cx.typing_env().as_query_input(inner_ty)) + .is_ok_and(|layout| !layout.is_1zst()) + { + let dcx = &DanglingPointerLocalContext { + body: def_id, + fn_ret: ty, + fn_ret_span: ret_ty.span, + fn_ret_inner: inner_ty, + fn_kind: match fn_kind { + FnKind::ItemFn(..) => "function", + FnKind::Method(..) => "method", + FnKind::Closure => "closure", + }, + }; + + // look for `return`s + DanglingPointerReturnSearcher { cx, dcx }.visit_body(body); + + // analyze implicit return expression + if let ExprKind::Block(block, None) = &body.value.kind + && let innermost_block = block.innermost_block() + && let Some(expr) = innermost_block.expr + { + lint_addr_of_local(cx, dcx, expr); + } + } + } + } +} + +struct DanglingPointerLocalContext<'tcx> { + body: LocalDefId, + fn_ret: Ty<'tcx>, + fn_ret_span: Span, + fn_ret_inner: Ty<'tcx>, + fn_kind: &'static str, +} + +struct DanglingPointerReturnSearcher<'lcx, 'tcx> { + cx: &'lcx LateContext<'tcx>, + dcx: &'lcx DanglingPointerLocalContext<'tcx>, +} + +impl<'tcx> Visitor<'tcx> for DanglingPointerReturnSearcher<'_, 'tcx> { + fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) -> Self::Result { + if let ExprKind::Ret(Some(expr)) = expr.kind { + lint_addr_of_local(self.cx, self.dcx, expr); + } + walk_expr(self, expr) + } +} + +/// Look for `&<path_to_local_in_same_body>` pattern and emit lint for it +fn lint_addr_of_local<'a>( + cx: &LateContext<'a>, + dcx: &DanglingPointerLocalContext<'a>, + expr: &'a Expr<'a>, +) { + // peel casts as they do not interest us here, we want the inner expression. + let (inner, _) = super::utils::peel_casts(cx, expr); + + if let ExprKind::AddrOf(_, _, inner_of) = inner.kind + && let ExprKind::Path(ref qpath) = inner_of.peel_blocks().kind + && let Res::Local(from) = cx.qpath_res(qpath, inner_of.hir_id) + && cx.tcx.hir_enclosing_body_owner(from) == dcx.body + { + cx.tcx.emit_node_span_lint( + DANGLING_POINTERS_FROM_LOCALS, + expr.hir_id, + expr.span, + DanglingPointersFromLocals { + ret_ty: dcx.fn_ret, + ret_ty_span: dcx.fn_ret_span, + fn_kind: dcx.fn_kind, + local_var: cx.tcx.hir_span(from), + local_var_name: cx.tcx.hir_ident(from), + local_var_ty: dcx.fn_ret_inner, + created_at: (expr.hir_id != inner.hir_id).then_some(inner.span), + }, + ); } } diff --git a/compiler/rustc_lint/src/default_could_be_derived.rs b/compiler/rustc_lint/src/default_could_be_derived.rs index b5fc083a095..7c39d8917ce 100644 --- a/compiler/rustc_lint/src/default_could_be_derived.rs +++ b/compiler/rustc_lint/src/default_could_be_derived.rs @@ -1,7 +1,8 @@ -use rustc_attr_data_structures::{AttributeKind, find_attr}; use rustc_data_structures::fx::FxHashMap; use rustc_errors::{Applicability, Diag}; use rustc_hir as hir; +use rustc_hir::attrs::AttributeKind; +use rustc_hir::find_attr; use rustc_middle::ty; use rustc_middle::ty::TyCtxt; use rustc_session::{declare_lint, impl_lint_pass}; diff --git a/compiler/rustc_lint/src/foreign_modules.rs b/compiler/rustc_lint/src/foreign_modules.rs index d6c402d481f..759e6c927b8 100644 --- a/compiler/rustc_lint/src/foreign_modules.rs +++ b/compiler/rustc_lint/src/foreign_modules.rs @@ -1,9 +1,10 @@ use rustc_abi::FIRST_VARIANT; -use rustc_attr_data_structures::{AttributeKind, find_attr}; use rustc_data_structures::stack::ensure_sufficient_stack; use rustc_data_structures::unord::{UnordMap, UnordSet}; use rustc_hir as hir; +use rustc_hir::attrs::AttributeKind; use rustc_hir::def::DefKind; +use rustc_hir::find_attr; use rustc_middle::query::Providers; use rustc_middle::ty::{self, AdtDef, Instance, Ty, TyCtxt}; use rustc_session::declare_lint; diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs index fd8d0f832aa..ef63c0dee8c 100644 --- a/compiler/rustc_lint/src/lints.rs +++ b/compiler/rustc_lint/src/lints.rs @@ -1188,6 +1188,22 @@ pub(crate) struct DanglingPointersFromTemporaries<'tcx> { pub temporary_span: Span, } +#[derive(LintDiagnostic)] +#[diag(lint_dangling_pointers_from_locals)] +#[note] +pub(crate) struct DanglingPointersFromLocals<'tcx> { + pub ret_ty: Ty<'tcx>, + #[label(lint_ret_ty)] + pub ret_ty_span: Span, + pub fn_kind: &'static str, + #[label(lint_local_var)] + pub local_var: Span, + pub local_var_name: Ident, + pub local_var_ty: Ty<'tcx>, + #[label(lint_created_at)] + pub created_at: Option<Span>, +} + // multiple_supertrait_upcastable.rs #[derive(LintDiagnostic)] #[diag(lint_multiple_supertrait_upcastable)] diff --git a/compiler/rustc_lint/src/nonstandard_style.rs b/compiler/rustc_lint/src/nonstandard_style.rs index 76e374deef6..7e5f43ba77f 100644 --- a/compiler/rustc_lint/src/nonstandard_style.rs +++ b/compiler/rustc_lint/src/nonstandard_style.rs @@ -1,11 +1,11 @@ use rustc_abi::ExternAbi; -use rustc_attr_data_structures::{AttributeKind, ReprAttr, find_attr}; use rustc_attr_parsing::AttributeParser; use rustc_errors::Applicability; +use rustc_hir::attrs::{AttributeKind, ReprAttr}; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{FnKind, Visitor}; -use rustc_hir::{AttrArgs, AttrItem, Attribute, GenericParamKind, PatExprKind, PatKind}; +use rustc_hir::{AttrArgs, AttrItem, Attribute, GenericParamKind, PatExprKind, PatKind, find_attr}; use rustc_middle::hir::nested_filter::All; use rustc_middle::ty; use rustc_session::config::CrateType; diff --git a/compiler/rustc_lint/src/pass_by_value.rs b/compiler/rustc_lint/src/pass_by_value.rs index a3cf3d568b1..4f65acd8001 100644 --- a/compiler/rustc_lint/src/pass_by_value.rs +++ b/compiler/rustc_lint/src/pass_by_value.rs @@ -1,6 +1,6 @@ -use rustc_attr_data_structures::{AttributeKind, find_attr}; +use rustc_hir::attrs::AttributeKind; use rustc_hir::def::Res; -use rustc_hir::{self as hir, AmbigArg, GenericArg, PathSegment, QPath, TyKind}; +use rustc_hir::{self as hir, AmbigArg, GenericArg, PathSegment, QPath, TyKind, find_attr}; use rustc_middle::ty; use rustc_session::{declare_lint_pass, declare_tool_lint}; diff --git a/compiler/rustc_lint/src/types/literal.rs b/compiler/rustc_lint/src/types/literal.rs index 2bac58ba23d..1febbff4bbf 100644 --- a/compiler/rustc_lint/src/types/literal.rs +++ b/compiler/rustc_lint/src/types/literal.rs @@ -1,11 +1,11 @@ use hir::{ExprKind, Node, is_range_literal}; use rustc_abi::{Integer, Size}; -use rustc_hir::HirId; +use rustc_hir::{HirId, attrs}; use rustc_middle::ty::Ty; use rustc_middle::ty::layout::IntegerExt; use rustc_middle::{bug, ty}; use rustc_span::Span; -use {rustc_ast as ast, rustc_attr_data_structures as attrs, rustc_hir as hir}; +use {rustc_ast as ast, rustc_hir as hir}; use crate::LateContext; use crate::context::LintContext; @@ -272,7 +272,7 @@ fn lint_int_literal<'tcx>( cx, hir_id, span, - attrs::IntType::SignedInt(ty::ast_int_ty(t)), + attrs::IntType::SignedInt(t), Integer::from_int_ty(cx, t).size(), repr_str, v, @@ -358,7 +358,7 @@ fn lint_uint_literal<'tcx>( cx, hir_id, span, - attrs::IntType::UnsignedInt(ty::ast_uint_ty(t)), + attrs::IntType::UnsignedInt(t), Integer::from_uint_ty(cx, t).size(), repr_str, lit_val, diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs index 00e40b515a3..22d89d24612 100644 --- a/compiler/rustc_lint/src/unused.rs +++ b/compiler/rustc_lint/src/unused.rs @@ -2,12 +2,12 @@ use std::iter; use rustc_ast::util::{classify, parser}; use rustc_ast::{self as ast, ExprKind, FnRetTy, HasAttrs as _, StmtKind}; -use rustc_attr_data_structures::{AttributeKind, find_attr}; use rustc_data_structures::fx::FxHashMap; use rustc_errors::{MultiSpan, pluralize}; +use rustc_hir::attrs::AttributeKind; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; -use rustc_hir::{self as hir, LangItem}; +use rustc_hir::{self as hir, LangItem, find_attr}; use rustc_infer::traits::util::elaborate; use rustc_middle::ty::{self, Ty, adjustment}; use rustc_session::{declare_lint, declare_lint_pass, impl_lint_pass}; |