diff options
| -rw-r--r-- | src/librustc_lint/types.rs | 46 | ||||
| -rw-r--r-- | src/test/compile-fail/lint-ctypes.rs | 6 | ||||
| -rw-r--r-- | src/test/run-pass/issue-34798.rs | 34 |
3 files changed, 79 insertions, 7 deletions
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs index 9669efa2d86..aff6de5a33d 100644 --- a/src/librustc_lint/types.rs +++ b/src/librustc_lint/types.rs @@ -341,6 +341,7 @@ struct ImproperCTypesVisitor<'a, 'tcx: 'a> { enum FfiResult { FfiSafe, + FfiPhantom, FfiUnsafe(&'static str), FfiBadStruct(DefId, &'static str), FfiBadUnion(DefId, &'static str), @@ -385,8 +386,11 @@ fn is_repr_nullable_ptr<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, 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 { + fn check_type_for_ffi(&self, + cache: &mut FxHashSet<Ty<'tcx>>, + ty: Ty<'tcx>) -> FfiResult { use self::FfiResult::*; + let cx = self.cx.tcx; // Protect against infinite recursion, for example @@ -399,6 +403,9 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { match ty.sty { ty::TyAdt(def, substs) => { + if def.is_phantom_data() { + return FfiPhantom; + } match def.adt_kind() { AdtKind::Struct => { if !cx.lookup_repr_hints(def.did).contains(&attr::ReprExtern) { @@ -407,18 +414,22 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { consider adding a #[repr(C)] attribute to the type"); } - // We can't completely trust repr(C) markings; make sure the - // fields are actually safe. if def.struct_variant().fields.is_empty() { return FfiUnsafe("found zero-size struct in foreign module, consider \ adding a member to this struct"); } + // We can't completely trust repr(C) markings; make sure the + // fields are actually safe. + let mut all_phantom = true; for field in &def.struct_variant().fields { let field_ty = cx.normalize_associated_type(&field.ty(cx, substs)); let r = self.check_type_for_ffi(cache, field_ty); match r { - FfiSafe => {} + FfiSafe => { + all_phantom = false; + } + FfiPhantom => {} FfiBadStruct(..) | FfiBadUnion(..) | FfiBadEnum(..) => { return r; } @@ -427,7 +438,8 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { } } } - FfiSafe + + if all_phantom { FfiPhantom } else { FfiSafe } } AdtKind::Union => { if !cx.lookup_repr_hints(def.did).contains(&attr::ReprExtern) { @@ -436,11 +448,20 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { consider adding a #[repr(C)] attribute to the type"); } + if def.struct_variant().fields.is_empty() { + return FfiUnsafe("found zero-size union in foreign module, consider \ + adding a member to this union"); + } + + let mut all_phantom = true; for field in &def.struct_variant().fields { let field_ty = cx.normalize_associated_type(&field.ty(cx, substs)); let r = self.check_type_for_ffi(cache, field_ty); match r { - FfiSafe => {} + FfiSafe => { + all_phantom = false; + } + FfiPhantom => {} FfiBadStruct(..) | FfiBadUnion(..) | FfiBadEnum(..) => { return r; } @@ -449,7 +470,8 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { } } } - FfiSafe + + if all_phantom { FfiPhantom } else { FfiSafe } } AdtKind::Enum => { if def.variants.is_empty() { @@ -500,6 +522,10 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { FfiBadStruct(..) | FfiBadUnion(..) | FfiBadEnum(..) => { return r; } + FfiPhantom => { + return FfiBadEnum(def.did, + "Found phantom data in enum variant"); + } FfiUnsafe(s) => { return FfiBadEnum(def.did, s); } @@ -593,6 +619,12 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { match self.check_type_for_ffi(&mut FxHashSet(), ty) { FfiResult::FfiSafe => {} + FfiResult::FfiPhantom => { + self.cx.span_lint(IMPROPER_CTYPES, + sp, + &format!("found zero-sized type composed only \ + of phantom-data in a foreign-function.")); + } FfiResult::FfiUnsafe(s) => { self.cx.span_lint(IMPROPER_CTYPES, sp, s); } diff --git a/src/test/compile-fail/lint-ctypes.rs b/src/test/compile-fail/lint-ctypes.rs index ccc25b58228..608b1eb0872 100644 --- a/src/test/compile-fail/lint-ctypes.rs +++ b/src/test/compile-fail/lint-ctypes.rs @@ -29,6 +29,9 @@ pub type RustBadRet = extern fn() -> Box<u32>; pub type CVoidRet = (); pub struct Foo; +#[repr(C)] +pub struct ZeroSizeWithPhantomData(::std::marker::PhantomData<i32>); + extern { pub fn ptr_type1(size: *const Foo); //~ ERROR: found struct without pub fn ptr_type2(size: *const Foo); //~ ERROR: found struct without @@ -40,6 +43,9 @@ extern { pub fn tuple_type(p: (i32, i32)); //~ ERROR found Rust tuple type pub fn tuple_type2(p: I32Pair); //~ ERROR found Rust tuple type pub fn zero_size(p: ZeroSize); //~ ERROR found zero-size struct + pub fn zero_size_phantom(p: ZeroSizeWithPhantomData); //~ ERROR found zero-sized type + pub fn zero_size_phantom_toplevel() + -> ::std::marker::PhantomData<bool>; //~ ERROR: found zero-sized type pub fn fn_type(p: RustFn); //~ ERROR found function pointer with Rust pub fn fn_type2(p: fn()); //~ ERROR found function pointer with Rust pub fn fn_contained(p: RustBadRet); //~ ERROR: found struct without diff --git a/src/test/run-pass/issue-34798.rs b/src/test/run-pass/issue-34798.rs new file mode 100644 index 00000000000..e217d07ed72 --- /dev/null +++ b/src/test/run-pass/issue-34798.rs @@ -0,0 +1,34 @@ +// Copyright 2017 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![forbid(improper_ctypes)] +#![allow(dead_code)] + +#[repr(C)] +pub struct Foo { + size: u8, + __value: ::std::marker::PhantomData<i32>, +} + +#[repr(C)] +pub struct ZeroSizeWithPhantomData<T>(::std::marker::PhantomData<T>); + +#[repr(C)] +pub struct Bar { + size: u8, + baz: ZeroSizeWithPhantomData<i32>, +} + +extern "C" { + pub fn bar(_: *mut Foo, _: *mut Bar); +} + +fn main() { +} |