Merge pull request rust-lang#4 from surechen/stable

add lint extern_without_repr

clippy_lints/src/declared_lints.rs

@@ -158,6 +158,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::exhaustive_items::EXHAUSTIVE_STRUCTS_INFO,
     crate::exit::EXIT_INFO,
     crate::explicit_write::EXPLICIT_WRITE_INFO,
+    crate::extern_without_repr::EXTERN_WITHOUT_REPR_INFO,
     crate::extra_unused_type_parameters::EXTRA_UNUSED_TYPE_PARAMETERS_INFO,
     crate::fallible_impl_from::FALLIBLE_IMPL_FROM_INFO,
     crate::float_literal::EXCESSIVE_PRECISION_INFO,

clippy_lints/src/extern_without_repr.rs

@@ -0,0 +1,97 @@
+use rustc_hir::{ForeignItemKind, Item, ItemKind, Node};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet_with_applicability;
+use rustc_errors::Applicability;
+//use rustc_hir::{Item, ItemKind};
+use clippy_utils::ty::walk_ptrs_hir_ty;
+use if_chain::if_chain;
+use rustc_hir_analysis::hir_ty_to_ty;
+use rustc_target::spec::abi::Abi;
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// ### Why is this bad?
+    ///
+    /// ### Example
+    /// ```rust
+    /// struct Foo3 {
+    ///     a: libc::c_char,
+    ///     b: libc::c_int,
+    ///     c: libc::c_longlong,
+    /// }
+    /// extern "C" fn c_abi_fn4(arg_one: u32, arg_two: *const Foo3) {}
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// #[repr(C)]
+    /// struct Foo3 {
+    ///     a: libc::c_char,
+    ///     b: libc::c_int,
+    ///     c: libc::c_longlong,
+    /// }
+    /// extern "C" fn c_abi_fn4(arg_one: u32, arg_two: *const Foo3) {}
+    /// ```
+    #[clippy::version = "1.72.0"]
+    pub EXTERN_WITHOUT_REPR,
+    pedantic,
+    "Should use repr to specifing data layout when struct is used in FFI"
+}
+declare_lint_pass!(ExternWithoutRepr => [EXTERN_WITHOUT_REPR]);
+
+impl<'tcx> LateLintPass<'tcx> for ExternWithoutRepr {
+    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
+        let msg = "Should use repr to specifing data layout when struct is used in FFI";
+        if let ItemKind::Fn(fn_sig, _, _) = &item.kind {
+            let mut app = Applicability::MaybeIncorrect;
+            let snippet = snippet_with_applicability(cx, fn_sig.span, "..", &mut app);
+            if let Some((fn_attrs, _)) = snippet.split_once("fn") {
+                if fn_attrs.contains("extern \"C\"") {
+                    for i in 0..fn_sig.decl.inputs.len() {
+                        let t = hir_ty_to_ty(cx.tcx, walk_ptrs_hir_ty(&fn_sig.decl.inputs[i]));
+                        if let Some(adt) = t.ty_adt_def() {
+                            let repr = adt.repr();
+                            if repr.packed() || repr.transparent() || repr.c() || repr.align.is_some() {
+                                continue;
+                            }
+                            let struct_span = cx.tcx.def_span(adt.did());
+                            span_lint_and_then(cx, EXTERN_WITHOUT_REPR, struct_span, msg, |_| {});
+                        }
+                    }
+                }
+            }
+        }
+
+        if_chain! {
+            if let ItemKind::ForeignMod { abi, items } = &item.kind;
+            if let Abi::C { unwind: _ } = abi;
+            then {
+                for i in 0..items.len() {
+                    if let Some(Node::ForeignItem(f)) = cx.tcx.hir().find(items[i].id.hir_id()) {
+                        if let ForeignItemKind::Fn(decl, ..) = f.kind {
+                            for j in 0..decl.inputs.len() {
+                                let t = hir_ty_to_ty(cx.tcx, walk_ptrs_hir_ty(&decl.inputs[j]));
+                                if let Some(adt) = t.ty_adt_def() {
+                                    let repr = adt.repr();
+                                    if repr.packed()
+                                        || repr.transparent()
+                                        || repr.c()
+                                        || repr.simd()
+                                        || repr.align.is_some()
+                                    {
+                                        continue;
+                                    }
+                                    let struct_span = cx.tcx.def_span(adt.did());
+                                    span_lint_and_then(cx, EXTERN_WITHOUT_REPR, struct_span, msg, |_| {});
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

clippy_lints/src/lib.rs

@@ -123,6 +123,7 @@ mod excessive_bools;
 mod exhaustive_items;
 mod exit;
 mod explicit_write;
+mod extern_without_repr;
 mod extra_unused_type_parameters;
 mod fallible_impl_from;
 mod float_literal;
@@ -970,6 +971,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_early_pass(|| Box::new(implicit_abi::ImplicitAbi));
     store.register_early_pass(|| Box::new(non_reentrant_functions::NonReentrantFunctions));
     store.register_early_pass(|| Box::new(loop_without_break_or_return::LoopWithoutBreakOrReturn));
+    store.register_late_pass(|_| Box::new(extern_without_repr::ExternWithoutRepr));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -34,6 +34,7 @@ error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown fie
            max-struct-bools
            max-suggested-slice-pattern-length
            max-trait-bounds
+           mem-unsafe-functions
            missing-docs-in-crate-items
            msrv
            pass-by-value-size-limit

tests/ui/extern_without_repr.rs

@@ -0,0 +1,44 @@
+#![allow(unused)]
+#![allow(improper_ctypes_definitions)]
+#![allow(improper_ctypes)]
+#![warn(clippy::extern_without_repr)]
+#![feature(rustc_private)]
+#![feature(core_intrinsics)]
+extern crate libc;
+
+#[repr(C)]
+struct Foo1 {
+    a: i32,
+    b: i64,
+    c: u128,
+}
+
+#[repr(packed)]
+#[derive(Debug)]
+struct Foo2 {
+    a: libc::c_char,
+    b: libc::c_int,
+    c: libc::c_longlong,
+}
+
+struct Foo3 {
+    a: libc::c_char,
+    b: libc::c_int,
+    c: libc::c_longlong,
+}
+
+extern "C" fn c_abi_fn1(arg_one: u32, arg_two: usize) {}
+extern "C" fn c_abi_fn2(arg_one: u32, arg_two: Foo1) {}
+extern "C" fn c_abi_fn3(arg_one: u32, arg_two: *const Foo2) {}
+extern "C" fn c_abi_fn4(arg_one: u32, arg_two: *const Foo3) {}
+
+extern "C" {
+    fn c_abi_in_block1(arg_one: u32, arg_two: usize);
+    fn c_abi_in_block2(arg_one: u32, arg_two: Foo1);
+    fn c_abi_in_block3(arg_one: u32, arg_two: Foo2);
+    fn c_abi_in_block4(arg_one: u32, arg_two: Foo3);
+}
+
+fn main() {
+    // test code goes here
+}

tests/ui/extern_without_repr.stderr

@@ -0,0 +1,10 @@
+error: Should use repr to specifing data layout when struct is used in FFI
+  --> $DIR/extern_without_repr.rs:24:1
+   |
+LL | struct Foo3 {
+   | ^^^^^^^^^^^
+   |
+   = note: `-D clippy::extern-without-repr` implied by `-D warnings`
+
+error: aborting due to previous error
+

tests/ui/non_reentrant_functions.stderr

@@ -1,3 +1,12 @@
+error[E0425]: cannot find function `localtime` in crate `libc`
+  --> $DIR/non_reentrant_functions.rs:11:25
+   |
+LL |         let _tm = libc::localtime(&0i64 as *const libc::time_t);
+   |                         ^^^^^^^^^ help: a function with a similar name exists: `localtime_s`
+  --> C:/Users/runneradmin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libc-0.2.140/src/windows/mod.rs:392:5
+   |
+   = note: similarly named function `localtime_s` defined here
+
 error: consider using the reentrant version of the function
   --> $DIR/non_reentrant_functions.rs:11:19
    |
@@ -18,5 +27,6 @@ error: consider using the reentrant version of the function
 LL |         token = unsafe { libc::strtok(std::ptr::null_mut(), delim) };
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0425`.