Auto merge of #52191 - SimonSapin:alloc_error_handler, r=alexcrichton

Implement #[alloc_error_handler]

This to-be-stable attribute is equivalent to `#[lang = "oom"]`. It is required when using the `alloc` crate without the `std` crate. It is called by `handle_alloc_error`, which is in turned called by "infallible" allocations APIs such as `Vec::push`.

src/test/compile-fail/alloc-error-handler-bad-signature-1.rs

@@ -0,0 +1,28 @@
+// Copyright 2018 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.
+
+// compile-flags:-C panic=abort
+
+#![feature(alloc_error_handler, panic_implementation)]
+#![no_std]
+#![no_main]
+
+use core::alloc::Layout;
+
+#[alloc_error_handler]
+fn oom(
+    info: &Layout, //~ ERROR argument should be `Layout`
+) -> () //~ ERROR return type should be `!`
+{
+    loop {}
+}
+
+#[panic_implementation]
+fn panic(_: &core::panic::PanicInfo) -> ! { loop {} }

src/test/compile-fail/alloc-error-handler-bad-signature-2.rs

@@ -0,0 +1,27 @@
+// Copyright 2018 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.
+
+// compile-flags:-C panic=abort
+
+#![feature(alloc_error_handler, panic_implementation)]
+#![no_std]
+#![no_main]
+
+struct Layout;
+
+#[alloc_error_handler]
+fn oom(
+    info: Layout, //~ ERROR argument should be `Layout`
+) { //~ ERROR return type should be `!`
+    loop {}
+}
+
+#[panic_implementation]
+fn panic(_: &core::panic::PanicInfo) -> ! { loop {} }

src/test/compile-fail/alloc-error-handler-bad-signature-3.rs

@@ -0,0 +1,25 @@
+// Copyright 2018 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.
+
+// compile-flags:-C panic=abort
+
+#![feature(alloc_error_handler, panic_implementation)]
+#![no_std]
+#![no_main]
+
+struct Layout;
+
+#[alloc_error_handler]
+fn oom() -> ! { //~ ERROR function should have one argument
+    loop {}
+}
+
+#[panic_implementation]
+fn panic(_: &core::panic::PanicInfo) -> ! { loop {} }

src/test/compile-fail/feature-gate-alloc-error-handler.rs

@@ -0,0 +1,21 @@
+// Copyright 2018 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.
+
+// compile-flags:-C panic=abort
+
+#![no_std]
+#![no_main]
+
+use core::alloc::Layout;
+
+#[alloc_error_handler] //~ ERROR #[alloc_error_handler] is an unstable feature (see issue #51540)
+fn oom(info: Layout) -> ! {
+    loop {}
+}

src/test/run-make-fulldeps/issue-51671/app.rs

@@ -14,6 +14,7 @@
 #![no_main]
 #![no_std]
 
+use core::alloc::Layout;
 use core::panic::PanicInfo;
 
 #[panic_implementation]
@@ -25,4 +26,6 @@ fn panic(_: &PanicInfo) -> ! {
 fn eh() {}
 
 #[lang = "oom"]
-fn oom() {}
+fn oom(_: Layout) -> ! {
+    loop {}
+}

src/test/run-pass/default-alloc-error-hook.rs

@@ -0,0 +1,28 @@
+// Copyright 2018 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.
+
+// ignore-cloudabi no processes
+// ignore-emscripten no processes
+
+use std::alloc::{Layout, handle_alloc_error};
+use std::env;
+use std::process::Command;
+use std::str;
+
+fn main() {
+    if env::args().len() > 1 {
+        handle_alloc_error(Layout::new::<[u8; 42]>())
+    }
+
+    let me = env::current_exe().unwrap();
+    let output = Command::new(&me).arg("next").output().unwrap();
+    assert!(!output.status.success(), "{:?} is a success", output.status);
+    assert_eq!(str::from_utf8(&output.stderr).unwrap(), "memory allocation of 42 bytes failed");
+}

src/test/ui/missing-alloc_error_handler.rs

@@ -0,0 +1,33 @@
+// Copyright 2015 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.
+
+// compile-flags: -C panic=abort
+// no-prefer-dynamic
+
+#![no_std]
+#![crate_type = "staticlib"]
+#![feature(panic_implementation, alloc_error_handler, alloc)]
+
+#[panic_implementation]
+fn panic(_: &core::panic::PanicInfo) -> ! {
+    loop {}
+}
+
+extern crate alloc;
+
+#[global_allocator]
+static A: MyAlloc = MyAlloc;
+
+struct MyAlloc;
+
+unsafe impl core::alloc::GlobalAlloc for MyAlloc {
+    unsafe fn alloc(&self, _: core::alloc::Layout) -> *mut u8 { 0 as _ }
+    unsafe fn dealloc(&self, _: *mut u8, _: core::alloc::Layout) {}
+}

src/test/ui/missing-alloc_error_handler.stderr

@@ -0,0 +1,4 @@
+error: `#[alloc_error_handler]` function required, but not found
+
+error: aborting due to previous error
+

src/test/ui/missing-allocator.rs

@@ -13,14 +13,16 @@
 
 #![no_std]
 #![crate_type = "staticlib"]
-#![feature(panic_implementation, lang_items, alloc)]
+#![feature(panic_implementation, alloc_error_handler, alloc)]
 
 #[panic_implementation]
 fn panic(_: &core::panic::PanicInfo) -> ! {
     loop {}
 }
 
-#[lang = "oom"]
-fn oom() {}
+#[alloc_error_handler]
+fn oom(_: core::alloc::Layout) -> ! {
+    loop {}
+}
 
 extern crate alloc;