Stabilize default_alloc_error_handler

compiler/rustc_error_messages/locales/en-US/metadata.ftl

@@ -166,12 +166,6 @@ metadata_conflicting_alloc_error_handler =
 metadata_global_alloc_required =
  no global memory allocator found but one is required; link to std or add `#[global_allocator]` to a static item that implements the GlobalAlloc trait
 
-metadata_alloc_func_required =
- `#[alloc_error_handler]` function required, but not found
-
-metadata_missing_alloc_error_handler =
- use `#![feature(default_alloc_error_handler)]` for a default error handler
-
 metadata_no_transitive_needs_dep =
  the crate `{$crate_name}` cannot depend on a crate that needs {$needs_crate_name}, but it depends on `{$deps_crate_name}`
 

compiler/rustc_feature/src/accepted.rs

@@ -126,6 +126,8 @@ declare_features! (
  (accepted, copy_closures, "1.26.0", Some(44490), None),
  /// Allows `crate` in paths.
  (accepted, crate_in_paths, "1.30.0", Some(45477), None),
+ /// Allows rustc to inject a default alloc_error_handler
+ (accepted, default_alloc_error_handler, "CURRENT_RUSTC_VERSION", Some(66741), None),
  /// Allows using assigning a default type to type parameters in algebraic data type definitions.
  (accepted, default_type_params, "1.0.0", None, None),
  /// Allows `#[deprecated]` attribute.

compiler/rustc_feature/src/active.rs

@@ -366,8 +366,6 @@ declare_features! (
  (active, debugger_visualizer, "1.62.0", Some(95939), None),
  /// Allows declarative macros 2.0 (`macro`).
  (active, decl_macro, "1.17.0", Some(39412), None),
- /// Allows rustc to inject a default alloc_error_handler
- (active, default_alloc_error_handler, "1.48.0", Some(66741), None),
  /// Allows default type parameters to influence type inference.
  (active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
  /// Allows using `#[deprecated_safe]` to deprecate the safeness of a function or trait

compiler/rustc_metadata/src/creader.rs

@@ -1,10 +1,9 @@
 //! Validates all used crates and extern libraries and loads their metadata
 
 use crate::errors::{
- AllocFuncRequired, ConflictingAllocErrorHandler, ConflictingGlobalAlloc, CrateNotPanicRuntime,
- GlobalAllocRequired, MissingAllocErrorHandler, NoMultipleAllocErrorHandler,
- NoMultipleGlobalAlloc, NoPanicStrategy, NoTransitiveNeedsDep, NotProfilerRuntime,
- ProfilerBuiltinsNeedsCore,
+ ConflictingAllocErrorHandler, ConflictingGlobalAlloc, CrateNotPanicRuntime,
+ GlobalAllocRequired, NoMultipleAllocErrorHandler, NoMultipleGlobalAlloc, NoPanicStrategy,
+ NoTransitiveNeedsDep, NotProfilerRuntime, ProfilerBuiltinsNeedsCore,
 };
 use crate::locator::{CrateError, CrateLocator, CratePaths};
 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
@@ -892,10 +891,6 @@ impl<'a> CrateLoader<'a> {
  } else {
  // The alloc crate provides a default allocation error handler if
  // one isn't specified.
- if !self.sess.features_untracked().default_alloc_error_handler {
- self.sess.emit_err(AllocFuncRequired);
- self.sess.emit_note(MissingAllocErrorHandler);
- }
  self.cstore.alloc_error_handler_kind = Some(AllocatorKind::Default);
  }
  }

compiler/rustc_metadata/src/errors.rs

@@ -371,14 +371,6 @@ pub struct ConflictingAllocErrorHandler {
 #[diag(metadata_global_alloc_required)]
 pub struct GlobalAllocRequired;
 
-#[derive(Diagnostic)]
-#[diag(metadata_alloc_func_required)]
-pub struct AllocFuncRequired;
-
-#[derive(Diagnostic)]
-#[diag(metadata_missing_alloc_error_handler)]
-pub struct MissingAllocErrorHandler;
-
 #[derive(Diagnostic)]
 #[diag(metadata_no_transitive_needs_dep)]
 pub struct NoTransitiveNeedsDep<'a> {

src/test/ui/allocator/no_std-alloc-error-handler-custom.rs

@@ -7,9 +7,10 @@
 // compile-flags:-C panic=abort
 // aux-build:helper.rs
 
-#![feature(start, rustc_private, new_uninit, panic_info_message, lang_items)]
+#![feature(rustc_private, lang_items)]
 #![feature(alloc_error_handler)]
 #![no_std]
+#![no_main]
 
 extern crate alloc;
 extern crate libc;
@@ -21,35 +22,30 @@ pub fn __aeabi_unwind_cpp_pr0() {}
 #[no_mangle]
 pub fn __aeabi_unwind_cpp_pr1() {}
 
-use core::ptr::null_mut;
-use core::alloc::{GlobalAlloc, Layout};
 use alloc::boxed::Box;
+use alloc::string::ToString;
+use core::alloc::{GlobalAlloc, Layout};
+use core::ptr::null_mut;
 
 extern crate helper;
 
 struct MyAllocator;
 
 #[alloc_error_handler]
-fn my_oom(layout: Layout) -> !
-{
+fn my_oom(layout: Layout) -> ! {
  use alloc::fmt::write;
  unsafe {
  let size = layout.size();
  let mut s = alloc::string::String::new();
  write(&mut s, format_args!("My OOM: failed to allocate {} bytes!\n", size)).unwrap();
- let s = s.as_str();
- libc::write(libc::STDERR_FILENO, s as *const _ as _, s.len());
+ libc::write(libc::STDERR_FILENO, s.as_ptr() as *const _, s.len());
  libc::exit(0)
  }
 }
 
 unsafe impl GlobalAlloc for MyAllocator {
  unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
- if layout.size() < 4096 {
- libc::malloc(layout.size()) as _
- } else {
- null_mut()
- }
+ if layout.size() < 4096 { libc::malloc(layout.size()) as _ } else { null_mut() }
  }
  unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
 }
@@ -60,26 +56,12 @@ static A: MyAllocator = MyAllocator;
 #[panic_handler]
 fn panic(panic_info: &core::panic::PanicInfo) -> ! {
  unsafe {
- if let Some(s) = panic_info.payload().downcast_ref::<&str>() {
- const PSTR: &str = "panic occurred: ";
- const CR: &str = "\n";
- libc::write(libc::STDERR_FILENO, PSTR as *const _ as _, PSTR.len());
- libc::write(libc::STDERR_FILENO, s as *const _ as _, s.len());
- libc::write(libc::STDERR_FILENO, CR as *const _ as _, CR.len());
- }
- if let Some(args) = panic_info.message() {
- let mut s = alloc::string::String::new();
- alloc::fmt::write(&mut s, *args).unwrap();
- let s = s.as_str();
- const PSTR: &str = "panic occurred: ";
- const CR: &str = "\n";
- libc::write(libc::STDERR_FILENO, PSTR as *const _ as _, PSTR.len());
- libc::write(libc::STDERR_FILENO, s as *const _ as _, s.len());
- libc::write(libc::STDERR_FILENO, CR as *const _ as _, CR.len());
- } else {
- const PSTR: &str = "panic occurred\n";
- libc::write(libc::STDERR_FILENO, PSTR as *const _ as _, PSTR.len());
- }
+ let s = panic_info.to_string();
+ const PSTR: &str = "panic occurred: ";
+ const CR: &str = "\n";
+ libc::write(libc::STDERR_FILENO, PSTR.as_ptr() as *const _, PSTR.len());
+ libc::write(libc::STDERR_FILENO, s.as_ptr() as *const _, s.len());
+ libc::write(libc::STDERR_FILENO, CR.as_ptr() as *const _, CR.len());
  libc::exit(1)
  }
 }
@@ -89,15 +71,14 @@ fn panic(panic_info: &core::panic::PanicInfo) -> ! {
 // in these libraries will refer to `rust_eh_personality` if LLVM can not *prove* the contents won't
 // unwind. So, for this test case we will define the symbol.
 #[lang = "eh_personality"]
-extern fn rust_eh_personality() {}
+extern "C" fn rust_eh_personality() {}
 
-#[derive(Debug)]
+#[derive(Default, Debug)]
 struct Page(#[allow(unused_tuple_struct_fields)] [[u64; 32]; 16]);
 
-#[start]
-pub fn main(_argc: isize, _argv: *const *const u8) -> isize {
- let zero = Box::<Page>::new_zeroed();
- let zero = unsafe { zero.assume_init() };
+#[no_mangle]
+fn main(_argc: i32, _argv: *const *const u8) -> isize {
+ let zero = Box::<Page>::new(Default::default());
  helper::work_with(&zero);
  1
 }

src/test/ui/allocator/no_std-alloc-error-handler-default.rs

@@ -6,11 +6,10 @@
 // only-linux
 // compile-flags:-C panic=abort
 // aux-build:helper.rs
-// gate-test-default_alloc_error_handler
 
-#![feature(start, rustc_private, new_uninit, panic_info_message, lang_items)]
-#![feature(default_alloc_error_handler)]
+#![feature(rustc_private, lang_items)]
 #![no_std]
+#![no_main]
 
 extern crate alloc;
 extern crate libc;
@@ -23,6 +22,7 @@ pub fn __aeabi_unwind_cpp_pr0() {}
 pub fn __aeabi_unwind_cpp_pr1() {}
 
 use alloc::boxed::Box;
+use alloc::string::ToString;
 use core::alloc::{GlobalAlloc, Layout};
 use core::ptr::null_mut;
 
@@ -32,11 +32,7 @@ struct MyAllocator;
 
 unsafe impl GlobalAlloc for MyAllocator {
  unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
- if layout.size() < 4096 {
- libc::malloc(layout.size()) as _
- } else {
- null_mut()
- }
+ if layout.size() < 4096 { libc::malloc(layout.size()) as _ } else { null_mut() }
  }
  unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
 }
@@ -47,26 +43,12 @@ static A: MyAllocator = MyAllocator;
 #[panic_handler]
 fn panic(panic_info: &core::panic::PanicInfo) -> ! {
  unsafe {
- if let Some(s) = panic_info.payload().downcast_ref::<&str>() {
- const PSTR: &str = "panic occurred: ";
- const CR: &str = "\n";
- libc::write(libc::STDERR_FILENO, PSTR as *const _ as _, PSTR.len());
- libc::write(libc::STDERR_FILENO, s as *const _ as _, s.len());
- libc::write(libc::STDERR_FILENO, CR as *const _ as _, CR.len());
- }
- if let Some(args) = panic_info.message() {
- let mut s = alloc::string::String::new();
- alloc::fmt::write(&mut s, *args).unwrap();
- let s = s.as_str();
- const PSTR: &str = "panic occurred: ";
- const CR: &str = "\n";
- libc::write(libc::STDERR_FILENO, PSTR as *const _ as _, PSTR.len());
- libc::write(libc::STDERR_FILENO, s as *const _ as _, s.len());
- libc::write(libc::STDERR_FILENO, CR as *const _ as _, CR.len());
- } else {
- const PSTR: &str = "panic occurred\n";
- libc::write(libc::STDERR_FILENO, PSTR as *const _ as _, PSTR.len());
- }
+ let s = panic_info.to_string();
+ const PSTR: &str = "panic occurred: ";
+ const CR: &str = "\n";
+ libc::write(libc::STDERR_FILENO, PSTR.as_ptr() as *const _, PSTR.len());
+ libc::write(libc::STDERR_FILENO, s.as_ptr() as *const _, s.len());
+ libc::write(libc::STDERR_FILENO, CR.as_ptr() as *const _, CR.len());
  libc::exit(0)
  }
 }
@@ -76,15 +58,14 @@ fn panic(panic_info: &core::panic::PanicInfo) -> ! {
 // in these libraries will refer to `rust_eh_personality` if LLVM can not *prove* the contents won't
 // unwind. So, for this test case we will define the symbol.
 #[lang = "eh_personality"]
-extern fn rust_eh_personality() {}
+extern "C" fn rust_eh_personality() {}
 
-#[derive(Debug)]
+#[derive(Default, Debug)]
 struct Page(#[allow(unused_tuple_struct_fields)] [[u64; 32]; 16]);
 
-#[start]
-pub fn main(_argc: isize, _argv: *const *const u8) -> isize {
- let zero = Box::<Page>::new_zeroed();
- let zero = unsafe { zero.assume_init() };
+#[no_mangle]
+fn main(_argc: i32, _argv: *const *const u8) -> isize {
+ let zero = Box::<Page>::new(Default::default());
  helper::work_with(&zero);
  1
 }