Remove #[alloc_error_handler] from the compiler and library

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -1,97 +0,0 @@
-use crate::errors;
-use crate::util::check_builtin_macro_attribute;
-
-use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, FnHeader, FnSig, Generics, StmtKind};
-use rustc_ast::{Fn, ItemKind, Stmt, TyKind, Unsafe};
-use rustc_expand::base::{Annotatable, ExtCtxt};
-use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::Span;
-use thin_vec::{thin_vec, ThinVec};
-
-pub fn expand(
-    ecx: &mut ExtCtxt<'_>,
-    _span: Span,
-    meta_item: &ast::MetaItem,
-    item: Annotatable,
-) -> Vec<Annotatable> {
-    check_builtin_macro_attribute(ecx, meta_item, sym::alloc_error_handler);
-
-    let orig_item = item.clone();
-
-    // Allow using `#[alloc_error_handler]` on an item statement
-    // FIXME - if we get deref patterns, use them to reduce duplication here
-    let (item, is_stmt, sig_span) =
-        if let Annotatable::Item(item) = &item
-            && let ItemKind::Fn(fn_kind) = &item.kind
-        {
-            (item, false, ecx.with_def_site_ctxt(fn_kind.sig.span))
-        } else if let Annotatable::Stmt(stmt) = &item
-            && let StmtKind::Item(item) = &stmt.kind
-            && let ItemKind::Fn(fn_kind) = &item.kind
-        {
-            (item, true, ecx.with_def_site_ctxt(fn_kind.sig.span))
-        } else {
-            ecx.sess.parse_sess.span_diagnostic.emit_err(errors::AllocErrorMustBeFn {span: item.span() });
-            return vec![orig_item];
-        };
-
-    // Generate a bunch of new items using the AllocFnFactory
-    let span = ecx.with_def_site_ctxt(item.span);
-
-    // Generate item statements for the allocator methods.
-    let stmts = thin_vec![generate_handler(ecx, item.ident, span, sig_span)];
-
-    // Generate anonymous constant serving as container for the allocator methods.
-    let const_ty = ecx.ty(sig_span, TyKind::Tup(ThinVec::new()));
-    let const_body = ecx.expr_block(ecx.block(span, stmts));
-    let const_item = ecx.item_const(span, Ident::new(kw::Underscore, span), const_ty, const_body);
-    let const_item = if is_stmt {
-        Annotatable::Stmt(P(ecx.stmt_item(span, const_item)))
-    } else {
-        Annotatable::Item(const_item)
-    };
-
-    // Return the original item and the new methods.
-    vec![orig_item, const_item]
-}
-
-// #[rustc_std_internal_symbol]
-// unsafe fn __rg_oom(size: usize, align: usize) -> ! {
-//     handler(core::alloc::Layout::from_size_align_unchecked(size, align))
-// }
-fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span) -> Stmt {
-    let usize = cx.path_ident(span, Ident::new(sym::usize, span));
-    let ty_usize = cx.ty_path(usize);
-    let size = Ident::from_str_and_span("size", span);
-    let align = Ident::from_str_and_span("align", span);
-
-    let layout_new = cx.std_path(&[sym::alloc, sym::Layout, sym::from_size_align_unchecked]);
-    let layout_new = cx.expr_path(cx.path(span, layout_new));
-    let layout = cx.expr_call(
-        span,
-        layout_new,
-        thin_vec![cx.expr_ident(span, size), cx.expr_ident(span, align)],
-    );
-
-    let call = cx.expr_call_ident(sig_span, handler, thin_vec![layout]);
-
-    let never = ast::FnRetTy::Ty(cx.ty(span, TyKind::Never));
-    let params = thin_vec![cx.param(span, size, ty_usize.clone()), cx.param(span, align, ty_usize)];
-    let decl = cx.fn_decl(params, never);
-    let header = FnHeader { unsafety: Unsafe::Yes(span), ..FnHeader::default() };
-    let sig = FnSig { decl, header, span: span };
-
-    let body = Some(cx.block_expr(call));
-    let kind = ItemKind::Fn(Box::new(Fn {
-        defaultness: ast::Defaultness::Final,
-        sig,
-        generics: Generics::default(),
-        body,
-    }));
-
-    let attrs = thin_vec![cx.attr_word(sym::rustc_std_internal_symbol, span)];
-
-    let item = cx.item(span, Ident::from_str_and_span("__rg_oom", span), attrs, kind);
-    cx.stmt_item(sig_span, item)
-}

compiler/rustc_builtin_macros/src/errors.rs

@@ -19,13 +19,6 @@ pub(crate) struct OneCfgPattern {
     pub(crate) span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(builtin_macros_alloc_error_must_be_fn)]
-pub(crate) struct AllocErrorMustBeFn {
-    #[primary_span]
-    pub(crate) span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(builtin_macros_assert_requires_boolean)]
 pub(crate) struct AssertRequiresBoolean {

compiler/rustc_builtin_macros/src/lib.rs

@@ -27,7 +27,6 @@ use rustc_expand::proc_macro::BangProcMacro;
 use rustc_macros::fluent_messages;
 use rustc_span::symbol::sym;
 
-mod alloc_error_handler;
 mod assert;
 mod cfg;
 mod cfg_accessible;
@@ -102,7 +101,6 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
     }
 
     register_attr! {
-        alloc_error_handler: alloc_error_handler::expand,
         bench: test::expand_bench,
         cfg_accessible: cfg_accessible::Expander,
         cfg_eval: cfg_eval::expand,