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Address code review comments. 

- Make `is_repr_nullable_ptr` freestanding again to avoid usage of
ImproperCTypesVisitor in ClashingExternDeclarations (and don't
accidentally revert the ParamEnv::reveal_all() fix from a week earlier)
- Revise match condition for 1 Adt, 1 primitive
- Generalise check for non-null type so that it would also work for
ranges which exclude any single value (all bits set, for example)
- Make is_repr_nullable_ptr return the representable type instead of
just a boolean, to avoid adding an additional, independent "source of
truth" about the FFI-compatibility of Option-like enums. Also, rename to
`repr_nullable_ptr`.
This commit is contained in:
jumbatm 2020-07-13 23:06:35 +10:00
parent 5e52edca52
commit 060666d0a4
5 changed files with 202 additions and 147 deletions
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109
src/librustc_lint/builtin.rs
View File

@ -20,7 +20,9 @@
//! If you define a new `LateLintPass`, you will also need to add it to the //! If you define a new `LateLintPass`, you will also need to add it to the
//! `late_lint_methods!` invocation in `lib.rs`. //! `late_lint_methods!` invocation in `lib.rs`.
use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext}; use crate::{
types::CItemKind, EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext,
};
use rustc_ast::ast::{self, Expr}; use rustc_ast::ast::{self, Expr};
use rustc_ast::attr::{self, HasAttrs}; use rustc_ast::attr::{self, HasAttrs};
use rustc_ast::tokenstream::{TokenStream, TokenTree}; use rustc_ast::tokenstream::{TokenStream, TokenTree};
@ -2144,7 +2146,13 @@ impl ClashingExternDeclarations {
/// Checks whether two types are structurally the same enough that the declarations shouldn't /// Checks whether two types are structurally the same enough that the declarations shouldn't
/// clash. We need this so we don't emit a lint when two modules both declare an extern struct, /// clash. We need this so we don't emit a lint when two modules both declare an extern struct,
/// with the same members (as the declarations shouldn't clash). /// with the same members (as the declarations shouldn't clash).
fn structurally_same_type<'tcx>(cx: &LateContext<'tcx>, a: Ty<'tcx>, b: Ty<'tcx>) -> bool { fn structurally_same_type<'tcx>(
cx: &LateContext<'tcx>,
a: Ty<'tcx>,
b: Ty<'tcx>,
ckind: CItemKind,
) -> bool {
debug!("structurally_same_type(cx, a = {:?}, b = {:?})", a, b);
let tcx = cx.tcx; let tcx = cx.tcx;
if a == b || rustc_middle::ty::TyS::same_type(a, b) { if a == b || rustc_middle::ty::TyS::same_type(a, b) {
// All nominally-same types are structurally same, too. // All nominally-same types are structurally same, too.
@ -2156,29 +2164,30 @@ impl ClashingExternDeclarations {
let b_kind = &b.kind; let b_kind = &b.kind;
use rustc_target::abi::LayoutOf; use rustc_target::abi::LayoutOf;
let compare_layouts = |a, b| { let compare_layouts = |a, b| -> bool {
let a_layout = &cx.layout_of(a).unwrap().layout.abi; &cx.layout_of(a).unwrap().layout.abi == &cx.layout_of(b).unwrap().layout.abi
let b_layout = &cx.layout_of(b).unwrap().layout.abi;
let result = a_layout == b_layout;
result
}; };
#[allow(rustc::usage_of_ty_tykind)]
let is_primitive_or_pointer =
|kind: &ty::TyKind<'_>| kind.is_primitive() || matches!(kind, RawPtr(..));
match (a_kind, b_kind) { match (a_kind, b_kind) {
(Adt(..), Adt(..)) => compare_layouts(a, b), (Adt(..), Adt(..)) => compare_layouts(a, b),
(Array(a_ty, a_const), Array(b_ty, b_const)) => { (Array(a_ty, a_const), Array(b_ty, b_const)) => {
// For arrays, we also check the constness of the type. // For arrays, we also check the constness of the type.
a_const.val == b_const.val a_const.val == b_const.val
&& Self::structurally_same_type(cx, a_const.ty, b_const.ty) && Self::structurally_same_type(cx, a_const.ty, b_const.ty, ckind)
&& Self::structurally_same_type(cx, a_ty, b_ty) && Self::structurally_same_type(cx, a_ty, b_ty, ckind)
} }
(Slice(a_ty), Slice(b_ty)) => Self::structurally_same_type(cx, a_ty, b_ty), (Slice(a_ty), Slice(b_ty)) => Self::structurally_same_type(cx, a_ty, b_ty, ckind),
(RawPtr(a_tymut), RawPtr(b_tymut)) => { (RawPtr(a_tymut), RawPtr(b_tymut)) => {
a_tymut.mutbl == a_tymut.mutbl a_tymut.mutbl == a_tymut.mutbl
&& Self::structurally_same_type(cx, &a_tymut.ty, &b_tymut.ty) && Self::structurally_same_type(cx, &a_tymut.ty, &b_tymut.ty, ckind)
} }
(Ref(_a_region, a_ty, a_mut), Ref(_b_region, b_ty, b_mut)) => { (Ref(_a_region, a_ty, a_mut), Ref(_b_region, b_ty, b_mut)) => {
// For structural sameness, we don't need the region to be same. // For structural sameness, we don't need the region to be same.
a_mut == b_mut && Self::structurally_same_type(cx, a_ty, b_ty) a_mut == b_mut && Self::structurally_same_type(cx, a_ty, b_ty, ckind)
} }
(FnDef(..), FnDef(..)) => { (FnDef(..), FnDef(..)) => {
let a_poly_sig = a.fn_sig(tcx); let a_poly_sig = a.fn_sig(tcx);
@ -2191,13 +2200,13 @@ impl ClashingExternDeclarations {
(a_sig.abi, a_sig.unsafety, a_sig.c_variadic) (a_sig.abi, a_sig.unsafety, a_sig.c_variadic)
== (b_sig.abi, b_sig.unsafety, b_sig.c_variadic) == (b_sig.abi, b_sig.unsafety, b_sig.c_variadic)
&& a_sig.inputs().iter().eq_by(b_sig.inputs().iter(), |a, b| { && a_sig.inputs().iter().eq_by(b_sig.inputs().iter(), |a, b| {
Self::structurally_same_type(cx, a, b) Self::structurally_same_type(cx, a, b, ckind)
}) })
&& Self::structurally_same_type(cx, a_sig.output(), b_sig.output()) && Self::structurally_same_type(cx, a_sig.output(), b_sig.output(), ckind)
} }
(Tuple(a_substs), Tuple(b_substs)) => { (Tuple(a_substs), Tuple(b_substs)) => {
a_substs.types().eq_by(b_substs.types(), |a_ty, b_ty| { a_substs.types().eq_by(b_substs.types(), |a_ty, b_ty| {
Self::structurally_same_type(cx, a_ty, b_ty) Self::structurally_same_type(cx, a_ty, b_ty, ckind)
}) })
} }
// For these, it's not quite as easy to define structural-sameness quite so easily. // For these, it's not quite as easy to define structural-sameness quite so easily.
@ -2210,58 +2219,27 @@ impl ClashingExternDeclarations {
| (GeneratorWitness(..), GeneratorWitness(..)) | (GeneratorWitness(..), GeneratorWitness(..))
| (Projection(..), Projection(..)) | (Projection(..), Projection(..))
| (Opaque(..), Opaque(..)) => false, | (Opaque(..), Opaque(..)) => false,
// These definitely should have been caught above. // These definitely should have been caught above.
(Bool, Bool) | (Char, Char) | (Never, Never) | (Str, Str) => unreachable!(), (Bool, Bool) | (Char, Char) | (Never, Never) | (Str, Str) => unreachable!(),
// Disjoint kinds. // An Adt and a primitive type. This can be FFI-safe is the ADT is an enum with a
(_, _) => { // non-null field.
// First, check if the conversion is FFI-safe. This can happen if the type is an (Adt(..), other_kind) | (other_kind, Adt(..))
// enum with a non-null field (see improper_ctypes). if is_primitive_or_pointer(other_kind) =>
let is_primitive_or_pointer = {
|ty: Ty<'tcx>| ty.is_primitive() || matches!(ty.kind, RawPtr(..)); let (primitive, adt) =
if (is_primitive_or_pointer(a) || is_primitive_or_pointer(b)) if is_primitive_or_pointer(&a.kind) { (a, b) } else { (b, a) };
&& !(is_primitive_or_pointer(a) && is_primitive_or_pointer(b)) if let Some(ty) = crate::types::repr_nullable_ptr(cx, adt, ckind) {
&& (matches!(a_kind, Adt(..)) || matches!(b_kind, Adt(..))) ty == primitive
/* ie, 1 adt and 1 primitive */ } else {
{ compare_layouts(a, b)
let (primitive_ty, adt_ty) =
if is_primitive_or_pointer(a) { (a, b) } else { (b, a) };
// First, check that the Adt is FFI-safe to use.
use crate::types::{ImproperCTypesMode, ImproperCTypesVisitor};
let vis =
ImproperCTypesVisitor { cx, mode: ImproperCTypesMode::Declarations };
if let Adt(def, substs) = adt_ty.kind {
let repr_nullable = vis.is_repr_nullable_ptr(adt_ty, def, substs);
if let Some(safe_ty) = repr_nullable {
let safe_ty_layout = &cx.layout_of(safe_ty).unwrap();
let primitive_ty_layout = &cx.layout_of(primitive_ty).unwrap();
use rustc_target::abi::Abi::*;
match (&safe_ty_layout.abi, &primitive_ty_layout.abi) {
(Scalar(safe), Scalar(primitive)) => {
// The two types are safe to convert between if `safe` is
// the non-zero version of `primitive`.
use std::ops::RangeInclusive;
let safe_range: &RangeInclusive<_> = &safe.valid_range;
let primitive_range: &RangeInclusive<_> =
&primitive.valid_range;
return primitive_range.end() == safe_range.end()
// This check works for both signed and unsigned types due to wraparound.
&& *safe_range.start() == 1
&& *primitive_range.start() == 0;
}
_ => {}
}
}
}
} }
// Otherwise, just compare the layouts. This may be underapproximate, but at
// the very least, will stop reads into uninitialised memory.
compare_layouts(a, b)
} }
// Otherwise, just compare the layouts. This may fail to lint for some
// incompatible types, but at the very least, will stop reads into
// uninitialised memory.
_ => compare_layouts(a, b),
} }
} }
} }
@ -2282,7 +2260,12 @@ impl<'tcx> LateLintPass<'tcx> for ClashingExternDeclarations {
existing_hid, existing_decl_ty, this_fi.hir_id, this_decl_ty existing_hid, existing_decl_ty, this_fi.hir_id, this_decl_ty
); );
// Check that the declarations match. // Check that the declarations match.
if !Self::structurally_same_type(cx, existing_decl_ty, this_decl_ty) { if !Self::structurally_same_type(
cx,
existing_decl_ty,
this_decl_ty,
CItemKind::Declaration,
) {
let orig_fi = tcx.hir().expect_foreign_item(existing_hid); let orig_fi = tcx.hir().expect_foreign_item(existing_hid);
let orig = Self::name_of_extern_decl(tcx, orig_fi); let orig = Self::name_of_extern_decl(tcx, orig_fi);

196
src/librustc_lint/types.rs
View File

@ -11,12 +11,13 @@ use rustc_index::vec::Idx;
use rustc_middle::mir::interpret::{sign_extend, truncate}; use rustc_middle::mir::interpret::{sign_extend, truncate};
use rustc_middle::ty::layout::{IntegerExt, SizeSkeleton}; use rustc_middle::ty::layout::{IntegerExt, SizeSkeleton};
use rustc_middle::ty::subst::SubstsRef; use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{self, AdtKind, Ty, TypeFoldable}; use rustc_middle::ty::{self, AdtKind, Ty, TyCtxt, TypeFoldable};
use rustc_span::source_map; use rustc_span::source_map;
use rustc_span::symbol::sym; use rustc_span::symbol::sym;
use rustc_span::{Span, DUMMY_SP}; use rustc_span::{Span, DUMMY_SP};
use rustc_target::abi::Abi;
use rustc_target::abi::{Integer, LayoutOf, TagEncoding, VariantIdx, Variants}; use rustc_target::abi::{Integer, LayoutOf, TagEncoding, VariantIdx, Variants};
use rustc_target::spec::abi::Abi; use rustc_target::spec::abi::Abi as SpecAbi;
use log::debug; use log::debug;
use std::cmp; use std::cmp;
@ -509,14 +510,15 @@ declare_lint! {
declare_lint_pass!(ImproperCTypesDefinitions => [IMPROPER_CTYPES_DEFINITIONS]); declare_lint_pass!(ImproperCTypesDefinitions => [IMPROPER_CTYPES_DEFINITIONS]);
crate enum ImproperCTypesMode { #[derive(Clone, Copy)]
Declarations, crate enum CItemKind {
Definitions, Declaration,
Definition,
} }
crate struct ImproperCTypesVisitor<'a, 'tcx> { struct ImproperCTypesVisitor<'a, 'tcx> {
crate cx: &'a LateContext<'tcx>, cx: &'a LateContext<'tcx>,
crate mode: ImproperCTypesMode, mode: CItemKind,
} }
enum FfiResult<'tcx> { enum FfiResult<'tcx> {
@ -525,53 +527,87 @@ enum FfiResult<'tcx> {
FfiUnsafe { ty: Ty<'tcx>, reason: String, help: Option<String> }, FfiUnsafe { ty: Ty<'tcx>, reason: String, help: Option<String> },
} }
impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { /// Is type known to be non-null?
/// Is type known to be non-null? fn ty_is_known_nonnull<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, mode: CItemKind) -> bool {
fn ty_is_known_nonnull(&self, ty: Ty<'tcx>) -> bool { let tcx = cx.tcx;
match ty.kind { match ty.kind {
ty::FnPtr(_) => true, ty::FnPtr(_) => true,
ty::Ref(..) => true, ty::Ref(..) => true,
ty::Adt(def, _) ty::Adt(def, _) if def.is_box() && matches!(mode, CItemKind::Definition) => true,
if def.is_box() && matches!(self.mode, ImproperCTypesMode::Definitions) => ty::Adt(def, substs) if def.repr.transparent() && !def.is_union() => {
{ let guaranteed_nonnull_optimization = tcx
true .get_attrs(def.did)
.iter()
.any(|a| a.check_name(sym::rustc_nonnull_optimization_guaranteed));
if guaranteed_nonnull_optimization {
return true;
} }
ty::Adt(def, substs) if def.repr.transparent() && !def.is_union() => { for variant in &def.variants {
let guaranteed_nonnull_optimization = self if let Some(field) = variant.transparent_newtype_field(tcx) {
.cx if ty_is_known_nonnull(cx, field.ty(tcx, substs), mode) {
.tcx return true;
.get_attrs(def.did)
.iter()
.any(|a| a.check_name(sym::rustc_nonnull_optimization_guaranteed));
if guaranteed_nonnull_optimization {
return true;
}
for variant in &def.variants {
if let Some(field) = variant.transparent_newtype_field(self.cx.tcx) {
if self.ty_is_known_nonnull(field.ty(self.cx.tcx, substs)) {
return true;
}
} }
} }
false
} }
_ => false,
false
}
_ => false,
}
}
/// Given a potentially non-null type `ty`, return its default, nullable type.
fn get_nullable_type<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
match ty.kind {
ty::Adt(field_def, field_substs) => {
let field_variants = &field_def.variants;
// We hit this case for #[repr(transparent)] structs with a single
// field.
debug_assert!(
field_variants.len() == 1 && field_variants[VariantIdx::new(0)].fields.len() == 1,
"inner ty not a newtype struct"
);
debug_assert!(field_def.repr.transparent(), "inner ty not transparent");
// As it's easy to get this wrong, it's worth noting that
// `inner_field_ty` is not the same as `field_ty`: Given Option<S>,
// where S is a transparent newtype of some type T, `field_ty`
// gives us S, while `inner_field_ty` is T.
let inner_field_ty =
field_def.variants[VariantIdx::new(0)].fields[0].ty(tcx, field_substs);
get_nullable_type(tcx, inner_field_ty)
}
ty::Int(ty) => tcx.mk_mach_int(ty),
ty::Uint(ty) => tcx.mk_mach_uint(ty),
ty::RawPtr(ty_mut) => tcx.mk_ptr(ty_mut),
// As these types are always non-null, the nullable equivalent of
// Option<T> of these types are their raw pointer counterparts.
ty::Ref(_region, ty, mutbl) => tcx.mk_ptr(ty::TypeAndMut { ty, mutbl }),
ty::FnPtr(..) => {
// There is no nullable equivalent for Rust's function pointers -- you
// must use an Option<fn(..) -> _> to represent it.
ty
}
// We should only ever reach this case if ty_is_known_nonnull is extended
// to other types.
ref unhandled => {
unreachable!("Unhandled scalar kind: {:?} while checking {:?}", unhandled, ty)
} }
} }
}
/// Check if this enum can be safely exported based on the "nullable pointer optimization". If /// Check if this enum can be safely exported based on the "nullable pointer optimization". If it
/// it can, return the known non-null field type, otherwise return `None`. Currently restricted /// can, return the the type that `ty` can be safely converted to, otherwise return `None`.
/// to function pointers, boxes, references, `core::num::NonZero*`, `core::ptr::NonNull`, and /// Currently restricted to function pointers, boxes, references, `core::num::NonZero*`,
/// `#[repr(transparent)]` newtypes. /// `core::ptr::NonNull`, and `#[repr(transparent)]` newtypes.
crate fn is_repr_nullable_ptr( /// FIXME: This duplicates code in codegen.
&self, crate fn repr_nullable_ptr<'tcx>(
ty: Ty<'tcx>, cx: &LateContext<'tcx>,
ty_def: &'tcx ty::AdtDef, ty: Ty<'tcx>,
substs: SubstsRef<'tcx>, ckind: CItemKind,
) -> Option<Ty<'tcx>> { ) -> Option<Ty<'tcx>> {
debug!("is_repr_nullable_ptr(cx, ty = {:?})", ty);
if let ty::Adt(ty_def, substs) = ty.kind {
if ty_def.variants.len() != 2 { if ty_def.variants.len() != 2 {
return None; return None;
} }
@ -590,23 +626,35 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
return None; return None;
} }
let field_ty = fields[0].ty(self.cx.tcx, substs); let field_ty = fields[0].ty(cx.tcx, substs);
if !self.ty_is_known_nonnull(field_ty) { if !ty_is_known_nonnull(cx, field_ty, ckind) {
return None; return None;
} }
// At this point, the field's type is known to be nonnull and the parent enum is // At this point, the field's type is known to be nonnull and the parent enum is Option-like.
// Option-like. If the computed size for the field and the enum are different, the non-null // If the computed size for the field and the enum are different, the nonnull optimization isn't
// optimization isn't being applied (and we've got a problem somewhere). // being applied (and we've got a problem somewhere).
let compute_size_skeleton = let compute_size_skeleton = |t| SizeSkeleton::compute(t, cx.tcx, cx.param_env).unwrap();
|t| SizeSkeleton::compute(t, self.cx.tcx, self.cx.param_env).unwrap();
if !compute_size_skeleton(ty).same_size(compute_size_skeleton(field_ty)) { if !compute_size_skeleton(ty).same_size(compute_size_skeleton(field_ty)) {
bug!("improper_ctypes: Option nonnull optimization not applied?"); bug!("improper_ctypes: Option nonnull optimization not applied?");
} }
Some(field_ty) // Return the nullable type this Option-like enum can be safely represented with.
let field_ty_abi = &cx.layout_of(field_ty).unwrap().abi;
if let Abi::Scalar(field_ty_scalar) = field_ty_abi {
match (field_ty_scalar.valid_range.start(), field_ty_scalar.valid_range.end()) {
(0, _) => bug!("Non-null optimisation extended to a non-zero value."),
(1, _) => {
return Some(get_nullable_type(cx.tcx, field_ty));
}
(start, end) => unreachable!("Unhandled start and end range: ({}, {})", start, end),
};
}
} }
None
}
impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
/// Check if the type is array and emit an unsafe type lint. /// Check if the type is array and emit an unsafe type lint.
fn check_for_array_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool { fn check_for_array_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool {
if let ty::Array(..) = ty.kind { if let ty::Array(..) = ty.kind {
@ -687,7 +735,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
fn check_type_for_ffi(&self, cache: &mut FxHashSet<Ty<'tcx>>, ty: Ty<'tcx>) -> FfiResult<'tcx> { fn check_type_for_ffi(&self, cache: &mut FxHashSet<Ty<'tcx>>, ty: Ty<'tcx>) -> FfiResult<'tcx> {
use FfiResult::*; use FfiResult::*;
let cx = self.cx.tcx; let tcx = self.cx.tcx;
// Protect against infinite recursion, for example // Protect against infinite recursion, for example
// `struct S(*mut S);`. // `struct S(*mut S);`.
@ -698,9 +746,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
} }
match ty.kind { match ty.kind {
ty::Adt(def, _) ty::Adt(def, _) if def.is_box() && matches!(self.mode, CItemKind::Definition) => {
if def.is_box() && matches!(self.mode, ImproperCTypesMode::Definitions) =>
{
FfiSafe FfiSafe
} }
@ -754,7 +800,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
// discriminant. // discriminant.
if !def.repr.c() && !def.repr.transparent() && def.repr.int.is_none() { if !def.repr.c() && !def.repr.transparent() && def.repr.int.is_none() {
// Special-case types like `Option<extern fn()>`. // Special-case types like `Option<extern fn()>`.
if self.is_repr_nullable_ptr(ty, def, substs).is_none() { if repr_nullable_ptr(self.cx, ty, self.mode).is_none() {
return FfiUnsafe { return FfiUnsafe {
ty, ty,
reason: "enum has no representation hint".into(), reason: "enum has no representation hint".into(),
@ -837,7 +883,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _) ty::RawPtr(ty::TypeAndMut { ty, .. }) | ty::Ref(_, ty, _)
if { if {
matches!(self.mode, ImproperCTypesMode::Definitions) matches!(self.mode, CItemKind::Definition)
&& ty.is_sized(self.cx.tcx.at(DUMMY_SP), self.cx.param_env) && ty.is_sized(self.cx.tcx.at(DUMMY_SP), self.cx.param_env)
} => } =>
{ {
@ -863,7 +909,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
}; };
} }
let sig = cx.erase_late_bound_regions(&sig); let sig = tcx.erase_late_bound_regions(&sig);
if !sig.output().is_unit() { if !sig.output().is_unit() {
let r = self.check_type_for_ffi(cache, sig.output()); let r = self.check_type_for_ffi(cache, sig.output());
match r { match r {
@ -895,9 +941,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
// `extern "C" fn` functions can have type parameters, which may or may not be FFI-safe, // `extern "C" fn` functions can have type parameters, which may or may not be FFI-safe,
// so they are currently ignored for the purposes of this lint. // so they are currently ignored for the purposes of this lint.
ty::Param(..) | ty::Projection(..) ty::Param(..) | ty::Projection(..) if matches!(self.mode, CItemKind::Definition) => {
if matches!(self.mode, ImproperCTypesMode::Definitions) =>
{
FfiSafe FfiSafe
} }
@ -922,14 +966,14 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
help: Option<&str>, help: Option<&str>,
) { ) {
let lint = match self.mode { let lint = match self.mode {
ImproperCTypesMode::Declarations => IMPROPER_CTYPES, CItemKind::Declaration => IMPROPER_CTYPES,
ImproperCTypesMode::Definitions => IMPROPER_CTYPES_DEFINITIONS, CItemKind::Definition => IMPROPER_CTYPES_DEFINITIONS,
}; };
self.cx.struct_span_lint(lint, sp, |lint| { self.cx.struct_span_lint(lint, sp, |lint| {
let item_description = match self.mode { let item_description = match self.mode {
ImproperCTypesMode::Declarations => "block", CItemKind::Declaration => "block",
ImproperCTypesMode::Definitions => "fn", CItemKind::Definition => "fn",
}; };
let mut diag = lint.build(&format!( let mut diag = lint.build(&format!(
"`extern` {} uses type `{}`, which is not FFI-safe", "`extern` {} uses type `{}`, which is not FFI-safe",
@ -1053,8 +1097,12 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
self.check_type_for_ffi_and_report_errors(span, ty, true, false); self.check_type_for_ffi_and_report_errors(span, ty, true, false);
} }
fn is_internal_abi(&self, abi: Abi) -> bool { fn is_internal_abi(&self, abi: SpecAbi) -> bool {
if let Abi::Rust | Abi::RustCall | Abi::RustIntrinsic | Abi::PlatformIntrinsic = abi { if let SpecAbi::Rust
| SpecAbi::RustCall
| SpecAbi::RustIntrinsic
| SpecAbi::PlatformIntrinsic = abi
{
true true
} else { } else {
false false
@ -1064,7 +1112,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations { impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations {
fn check_foreign_item(&mut self, cx: &LateContext<'_>, it: &hir::ForeignItem<'_>) { fn check_foreign_item(&mut self, cx: &LateContext<'_>, it: &hir::ForeignItem<'_>) {
let mut vis = ImproperCTypesVisitor { cx, mode: ImproperCTypesMode::Declarations }; let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Declaration };
let abi = cx.tcx.hir().get_foreign_abi(it.hir_id); let abi = cx.tcx.hir().get_foreign_abi(it.hir_id);
if !vis.is_internal_abi(abi) { if !vis.is_internal_abi(abi) {
@ -1099,7 +1147,7 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions {
_ => return, _ => return,
}; };
let mut vis = ImproperCTypesVisitor { cx, mode: ImproperCTypesMode::Definitions }; let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition };
if !vis.is_internal_abi(abi) { if !vis.is_internal_abi(abi) {
vis.check_foreign_fn(hir_id, decl); vis.check_foreign_fn(hir_id, decl);
} }

15
src/librustc_middle/ty/sty.rs
View File

@ -202,6 +202,16 @@ pub enum TyKind<'tcx> {
Error(DelaySpanBugEmitted), Error(DelaySpanBugEmitted),
} }
impl TyKind<'tcx> {
#[inline]
pub fn is_primitive(&self) -> bool {
match self {
Bool | Char | Int(_) | Uint(_) | Float(_) => true,
_ => false,
}
}
}
/// A type that is not publicly constructable. This prevents people from making `TyKind::Error` /// A type that is not publicly constructable. This prevents people from making `TyKind::Error`
/// except through `tcx.err*()`. /// except through `tcx.err*()`.
#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, PartialOrd, Ord)] #[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, PartialOrd, Ord)]
@ -1766,10 +1776,7 @@ impl<'tcx> TyS<'tcx> {
#[inline] #[inline]
pub fn is_primitive(&self) -> bool { pub fn is_primitive(&self) -> bool {
match self.kind { self.kind.is_primitive()
Bool | Char | Int(_) | Uint(_) | Float(_) => true,
_ => false,
}
} }
#[inline] #[inline]

5
src/test/ui/lint/clashing-extern-fn.rs
View File

@ -181,6 +181,7 @@ mod transparent {
use super::T; use super::T;
extern "C" { extern "C" {
fn transparent() -> T; fn transparent() -> T;
fn transparent_incorrect() -> T;
} }
} }
@ -189,6 +190,10 @@ mod transparent {
// Shouldn't warn here, because repr(transparent) guarantees that T's layout is the // Shouldn't warn here, because repr(transparent) guarantees that T's layout is the
// same as just the usize. // same as just the usize.
fn transparent() -> usize; fn transparent() -> usize;
// Should warn, because there's a signedness conversion here:
fn transparent_incorrect() -> isize;
//~^ WARN `transparent_incorrect` redeclared with a different signature
} }
} }
} }

24
src/test/ui/lint/clashing-extern-fn.stderr
View File

@ -105,8 +105,20 @@ LL | fn draw_point(p: Point);
= note: expected `unsafe extern "C" fn(sameish_members::a::Point)` = note: expected `unsafe extern "C" fn(sameish_members::a::Point)`
found `unsafe extern "C" fn(sameish_members::b::Point)` found `unsafe extern "C" fn(sameish_members::b::Point)`
warning: `transparent_incorrect` redeclared with a different signature
--> $DIR/clashing-extern-fn.rs:195:13
|
LL | fn transparent_incorrect() -> T;
| -------------------------------- `transparent_incorrect` previously declared here
...
LL | fn transparent_incorrect() -> isize;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this signature doesn't match the previous declaration
|
= note: expected `unsafe extern "C" fn() -> transparent::T`
found `unsafe extern "C" fn() -> isize`
warning: `missing_return_type` redeclared with a different signature warning: `missing_return_type` redeclared with a different signature
--> $DIR/clashing-extern-fn.rs:208:13 --> $DIR/clashing-extern-fn.rs:213:13
| |
LL | fn missing_return_type() -> usize; LL | fn missing_return_type() -> usize;
| ---------------------------------- `missing_return_type` previously declared here | ---------------------------------- `missing_return_type` previously declared here
@ -118,7 +130,7 @@ LL | fn missing_return_type();
found `unsafe extern "C" fn()` found `unsafe extern "C" fn()`
warning: `non_zero_usize` redeclared with a different signature warning: `non_zero_usize` redeclared with a different signature
--> $DIR/clashing-extern-fn.rs:226:13 --> $DIR/clashing-extern-fn.rs:231:13
| |
LL | fn non_zero_usize() -> core::num::NonZeroUsize; LL | fn non_zero_usize() -> core::num::NonZeroUsize;
| ----------------------------------------------- `non_zero_usize` previously declared here | ----------------------------------------------- `non_zero_usize` previously declared here
@ -130,7 +142,7 @@ LL | fn non_zero_usize() -> usize;
found `unsafe extern "C" fn() -> usize` found `unsafe extern "C" fn() -> usize`
warning: `non_null_ptr` redeclared with a different signature warning: `non_null_ptr` redeclared with a different signature
--> $DIR/clashing-extern-fn.rs:228:13 --> $DIR/clashing-extern-fn.rs:233:13
| |
LL | fn non_null_ptr() -> core::ptr::NonNull<usize>; LL | fn non_null_ptr() -> core::ptr::NonNull<usize>;
| ----------------------------------------------- `non_null_ptr` previously declared here | ----------------------------------------------- `non_null_ptr` previously declared here
@ -142,7 +154,7 @@ LL | fn non_null_ptr() -> *const usize;
found `unsafe extern "C" fn() -> *const usize` found `unsafe extern "C" fn() -> *const usize`
warning: `option_non_zero_usize_incorrect` redeclared with a different signature warning: `option_non_zero_usize_incorrect` redeclared with a different signature
--> $DIR/clashing-extern-fn.rs:254:13 --> $DIR/clashing-extern-fn.rs:259:13
| |
LL | fn option_non_zero_usize_incorrect() -> usize; LL | fn option_non_zero_usize_incorrect() -> usize;
| ---------------------------------------------- `option_non_zero_usize_incorrect` previously declared here | ---------------------------------------------- `option_non_zero_usize_incorrect` previously declared here
@ -154,7 +166,7 @@ LL | fn option_non_zero_usize_incorrect() -> isize;
found `unsafe extern "C" fn() -> isize` found `unsafe extern "C" fn() -> isize`
warning: `option_non_null_ptr_incorrect` redeclared with a different signature warning: `option_non_null_ptr_incorrect` redeclared with a different signature
--> $DIR/clashing-extern-fn.rs:256:13 --> $DIR/clashing-extern-fn.rs:261:13
| |
LL | fn option_non_null_ptr_incorrect() -> *const usize; LL | fn option_non_null_ptr_incorrect() -> *const usize;
| --------------------------------------------------- `option_non_null_ptr_incorrect` previously declared here | --------------------------------------------------- `option_non_null_ptr_incorrect` previously declared here
@ -165,5 +177,5 @@ LL | fn option_non_null_ptr_incorrect() -> *const isize;
= note: expected `unsafe extern "C" fn() -> *const usize` = note: expected `unsafe extern "C" fn() -> *const usize`
found `unsafe extern "C" fn() -> *const isize` found `unsafe extern "C" fn() -> *const isize`
warning: 13 warnings emitted warning: 14 warnings emitted