Rollup of 12 pull requests

compiler/rustc_ast/src/entry.rs

@@ -1,7 +1,5 @@
 use rustc_span::{Symbol, sym};
 
-use crate::attr::{self, AttributeExt};
-
 #[derive(Debug)]
 pub enum EntryPointType {
     /// This function is not an entrypoint.
@@ -30,11 +28,11 @@ pub enum EntryPointType {
 }
 
 pub fn entry_point_type(
-    attrs: &[impl AttributeExt],
+    has_rustc_main: bool,
     at_root: bool,
     name: Option<Symbol>,
 ) -> EntryPointType {
-    if attr::contains_name(attrs, sym::rustc_main) {
+    if has_rustc_main {
         EntryPointType::RustcMainAttr
     } else if let Some(name) = name
         && name == sym::main

compiler/rustc_ast/src/expand/allocator.rs

@@ -3,7 +3,9 @@ use rustc_span::{Symbol, sym};
 
 #[derive(Clone, Debug, Copy, Eq, PartialEq, HashStable_Generic)]
 pub enum AllocatorKind {
+    /// Use `#[global_allocator]` as global allocator.
     Global,
+    /// Use the default implementation in libstd as global allocator.
     Default,
 }
 
@@ -15,23 +17,22 @@ pub fn default_fn_name(base: Symbol) -> String {
     format!("__rdl_{base}")
 }
 
-pub fn alloc_error_handler_name(alloc_error_handler_kind: AllocatorKind) -> &'static str {
-    match alloc_error_handler_kind {
-        AllocatorKind::Global => "__rg_oom",
-        AllocatorKind::Default => "__rdl_oom",
-    }
-}
-
+pub const ALLOC_ERROR_HANDLER: Symbol = sym::alloc_error_handler;
 pub const NO_ALLOC_SHIM_IS_UNSTABLE: &str = "__rust_no_alloc_shim_is_unstable_v2";
 
+/// Argument or return type for methods in the allocator shim
+#[derive(Copy, Clone)]
 pub enum AllocatorTy {
     Layout,
+    Never,
     Ptr,
     ResultPtr,
     Unit,
     Usize,
 }
 
+/// A method that will be codegened in the allocator shim.
+#[derive(Copy, Clone)]
 pub struct AllocatorMethod {
     pub name: Symbol,
     pub inputs: &'static [AllocatorMethodInput],

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -1,9 +1,18 @@
 use super::prelude::*;
 use super::util::parse_single_integer;
 
-pub(crate) struct RustcLayoutScalarValidRangeStart;
+pub(crate) struct RustcMainParser;
 
-impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeStart {
+impl<S: Stage> NoArgsAttributeParser<S> for RustcMainParser {
+    const PATH: &'static [Symbol] = &[sym::rustc_main];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcMain;
+}
+
+pub(crate) struct RustcLayoutScalarValidRangeStartParser;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeStartParser {
     const PATH: &'static [Symbol] = &[sym::rustc_layout_scalar_valid_range_start];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
@@ -16,9 +25,9 @@ impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeStart {
     }
 }
 
-pub(crate) struct RustcLayoutScalarValidRangeEnd;
+pub(crate) struct RustcLayoutScalarValidRangeEndParser;
 
-impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeEnd {
+impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeEndParser {
     const PATH: &'static [Symbol] = &[sym::rustc_layout_scalar_valid_range_end];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;

compiler/rustc_attr_parsing/src/context.rs

@@ -53,7 +53,7 @@ use crate::attributes::proc_macro_attrs::{
 use crate::attributes::prototype::CustomMirParser;
 use crate::attributes::repr::{AlignParser, AlignStaticParser, ReprParser};
 use crate::attributes::rustc_internal::{
-    RustcLayoutScalarValidRangeEnd, RustcLayoutScalarValidRangeStart,
+    RustcLayoutScalarValidRangeEndParser, RustcLayoutScalarValidRangeStartParser, RustcMainParser,
     RustcObjectLifetimeDefaultParser, RustcSimdMonomorphizeLaneLimitParser,
 };
 use crate::attributes::semantics::MayDangleParser;
@@ -197,8 +197,8 @@ attribute_parsers!(
         Single<RecursionLimitParser>,
         Single<RustcBuiltinMacroParser>,
         Single<RustcForceInlineParser>,
-        Single<RustcLayoutScalarValidRangeEnd>,
-        Single<RustcLayoutScalarValidRangeStart>,
+        Single<RustcLayoutScalarValidRangeEndParser>,
+        Single<RustcLayoutScalarValidRangeStartParser>,
         Single<RustcObjectLifetimeDefaultParser>,
         Single<RustcSimdMonomorphizeLaneLimitParser>,
         Single<SanitizeParser>,
@@ -238,6 +238,7 @@ attribute_parsers!(
         Single<WithoutArgs<ProcMacroParser>>,
         Single<WithoutArgs<PubTransparentParser>>,
         Single<WithoutArgs<RustcCoherenceIsCoreParser>>,
+        Single<WithoutArgs<RustcMainParser>>,
         Single<WithoutArgs<SpecializationTraitParser>>,
         Single<WithoutArgs<StdInternalSymbolParser>>,
         Single<WithoutArgs<TrackCallerParser>>,

compiler/rustc_builtin_macros/src/alloc_error_handler.rs

@@ -1,3 +1,4 @@
+use rustc_ast::expand::allocator::{ALLOC_ERROR_HANDLER, global_fn_name};
 use rustc_ast::{
     self as ast, Fn, FnHeader, FnSig, Generics, ItemKind, Safety, Stmt, StmtKind, TyKind,
 };
@@ -55,7 +56,7 @@ pub(crate) fn expand(
 }
 
 // #[rustc_std_internal_symbol]
-// unsafe fn __rg_oom(size: usize, align: usize) -> ! {
+// unsafe fn __rust_alloc_error_handler(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 {
@@ -84,7 +85,7 @@ fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span
     let kind = ItemKind::Fn(Box::new(Fn {
         defaultness: ast::Defaultness::Final,
         sig,
-        ident: Ident::from_str_and_span("__rg_oom", span),
+        ident: Ident::from_str_and_span(&global_fn_name(ALLOC_ERROR_HANDLER), span),
         generics: Generics::default(),
         contract: None,
         body,

compiler/rustc_builtin_macros/src/global_allocator.rs

@@ -151,7 +151,7 @@ impl AllocFnFactory<'_, '_> {
                 self.cx.expr_ident(self.span, ident)
             }
 
-            AllocatorTy::ResultPtr | AllocatorTy::Unit => {
+            AllocatorTy::Never | AllocatorTy::ResultPtr | AllocatorTy::Unit => {
                 panic!("can't convert AllocatorTy to an argument")
             }
         }
@@ -163,7 +163,7 @@ impl AllocFnFactory<'_, '_> {
 
             AllocatorTy::Unit => self.cx.ty(self.span, TyKind::Tup(ThinVec::new())),
 
-            AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
+            AllocatorTy::Layout | AllocatorTy::Never | AllocatorTy::Usize | AllocatorTy::Ptr => {
                 panic!("can't convert `AllocatorTy` to an output")
             }
         }

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -3,6 +3,7 @@
 use std::mem;
 
 use rustc_ast as ast;
+use rustc_ast::attr::contains_name;
 use rustc_ast::entry::EntryPointType;
 use rustc_ast::mut_visit::*;
 use rustc_ast::visit::Visitor;
@@ -172,9 +173,11 @@ impl<'a> Visitor<'a> for InnerItemLinter<'_> {
 
 fn entry_point_type(item: &ast::Item, at_root: bool) -> EntryPointType {
     match &item.kind {
-        ast::ItemKind::Fn(fn_) => {
-            rustc_ast::entry::entry_point_type(&item.attrs, at_root, Some(fn_.ident.name))
-        }
+        ast::ItemKind::Fn(fn_) => rustc_ast::entry::entry_point_type(
+            contains_name(&item.attrs, sym::rustc_main),
+            at_root,
+            Some(fn_.ident.name),
+        ),
         _ => EntryPointType::None,
     }
 }

compiler/rustc_codegen_cranelift/src/allocator.rs

@@ -3,10 +3,9 @@
 
 use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
 use rustc_ast::expand::allocator::{
-    ALLOCATOR_METHODS, AllocatorKind, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE,
-    alloc_error_handler_name, default_fn_name, global_fn_name,
+    AllocatorMethod, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE, default_fn_name, global_fn_name,
 };
-use rustc_codegen_ssa::base::allocator_kind_for_codegen;
+use rustc_codegen_ssa::base::{allocator_kind_for_codegen, allocator_shim_contents};
 use rustc_session::config::OomStrategy;
 use rustc_symbol_mangling::mangle_internal_symbol;
 
@@ -15,75 +14,57 @@ use crate::prelude::*;
 /// Returns whether an allocator shim was created
 pub(crate) fn codegen(tcx: TyCtxt<'_>, module: &mut dyn Module) -> bool {
     let Some(kind) = allocator_kind_for_codegen(tcx) else { return false };
-    codegen_inner(
-        tcx,
-        module,
-        kind,
-        tcx.alloc_error_handler_kind(()).unwrap(),
-        tcx.sess.opts.unstable_opts.oom,
-    );
+    let methods = allocator_shim_contents(tcx, kind);
+    codegen_inner(tcx, module, &methods, tcx.sess.opts.unstable_opts.oom);
     true
 }
 
 fn codegen_inner(
     tcx: TyCtxt<'_>,
     module: &mut dyn Module,
-    kind: AllocatorKind,
-    alloc_error_handler_kind: AllocatorKind,
+    methods: &[AllocatorMethod],
     oom_strategy: OomStrategy,
 ) {
     let usize_ty = module.target_config().pointer_type();
 
-    if kind == AllocatorKind::Default {
-        for method in ALLOCATOR_METHODS {
-            let mut arg_tys = Vec::with_capacity(method.inputs.len());
-            for input in method.inputs.iter() {
-                match input.ty {
-                    AllocatorTy::Layout => {
-                        arg_tys.push(usize_ty); // size
-                        arg_tys.push(usize_ty); // align
-                    }
-                    AllocatorTy::Ptr => arg_tys.push(usize_ty),
-                    AllocatorTy::Usize => arg_tys.push(usize_ty),
+    for method in methods {
+        let mut arg_tys = Vec::with_capacity(method.inputs.len());
+        for input in method.inputs.iter() {
+            match input.ty {
+                AllocatorTy::Layout => {
+                    arg_tys.push(usize_ty); // size
+                    arg_tys.push(usize_ty); // align
+                }
+                AllocatorTy::Ptr => arg_tys.push(usize_ty),
+                AllocatorTy::Usize => arg_tys.push(usize_ty),
 
-                    AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"),
+                AllocatorTy::Never | AllocatorTy::ResultPtr | AllocatorTy::Unit => {
+                    panic!("invalid allocator arg")
                 }
             }
-            let output = match method.output {
-                AllocatorTy::ResultPtr => Some(usize_ty),
-                AllocatorTy::Unit => None,
+        }
+        let output = match method.output {
+            AllocatorTy::ResultPtr => Some(usize_ty),
+            AllocatorTy::Never | AllocatorTy::Unit => None,
 
-                AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
-                    panic!("invalid allocator output")
-                }
-            };
+            AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
+                panic!("invalid allocator output")
+            }
+        };
 
-            let sig = Signature {
-                call_conv: module.target_config().default_call_conv,
-                params: arg_tys.iter().cloned().map(AbiParam::new).collect(),
-                returns: output.into_iter().map(AbiParam::new).collect(),
-            };
-            crate::common::create_wrapper_function(
-                module,
-                sig,
-                &mangle_internal_symbol(tcx, &global_fn_name(method.name)),
-                &mangle_internal_symbol(tcx, &default_fn_name(method.name)),
-            );
-        }
+        let sig = Signature {
+            call_conv: module.target_config().default_call_conv,
+            params: arg_tys.iter().cloned().map(AbiParam::new).collect(),
+            returns: output.into_iter().map(AbiParam::new).collect(),
+        };
+        crate::common::create_wrapper_function(
+            module,
+            sig,
+            &mangle_internal_symbol(tcx, &global_fn_name(method.name)),
+            &mangle_internal_symbol(tcx, &default_fn_name(method.name)),
+        );
     }
 
-    let sig = Signature {
-        call_conv: module.target_config().default_call_conv,
-        params: vec![AbiParam::new(usize_ty), AbiParam::new(usize_ty)],
-        returns: vec![],
-    };
-    crate::common::create_wrapper_function(
-        module,
-        sig,
-        &mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
-        &mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
-    );
-
     {
         let sig = Signature {
             call_conv: module.target_config().default_call_conv,

compiler/rustc_codegen_gcc/src/allocator.rs

@@ -2,8 +2,7 @@
 use gccjit::FnAttribute;
 use gccjit::{Context, FunctionType, RValue, ToRValue, Type};
 use rustc_ast::expand::allocator::{
-    ALLOCATOR_METHODS, AllocatorKind, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE,
-    alloc_error_handler_name, default_fn_name, global_fn_name,
+    AllocatorMethod, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE, default_fn_name, global_fn_name,
 };
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
@@ -18,8 +17,7 @@ pub(crate) unsafe fn codegen(
     tcx: TyCtxt<'_>,
     mods: &mut GccContext,
     _module_name: &str,
-    kind: AllocatorKind,
-    alloc_error_handler_kind: AllocatorKind,
+    methods: &[AllocatorMethod],
 ) {
     let context = &mods.context;
     let usize = match tcx.sess.target.pointer_width {
@@ -31,45 +29,35 @@ pub(crate) unsafe fn codegen(
     let i8 = context.new_type::<i8>();
     let i8p = i8.make_pointer();
 
-    if kind == AllocatorKind::Default {
-        for method in ALLOCATOR_METHODS {
-            let mut types = Vec::with_capacity(method.inputs.len());
-            for input in method.inputs.iter() {
-                match input.ty {
-                    AllocatorTy::Layout => {
-                        types.push(usize);
-                        types.push(usize);
-                    }
-                    AllocatorTy::Ptr => types.push(i8p),
-                    AllocatorTy::Usize => types.push(usize),
-
-                    AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"),
+    for method in methods {
+        let mut types = Vec::with_capacity(method.inputs.len());
+        for input in method.inputs.iter() {
+            match input.ty {
+                AllocatorTy::Layout => {
+                    types.push(usize);
+                    types.push(usize);
                 }
-            }
-            let output = match method.output {
-                AllocatorTy::ResultPtr => Some(i8p),
-                AllocatorTy::Unit => None,
+                AllocatorTy::Ptr => types.push(i8p),
+                AllocatorTy::Usize => types.push(usize),
 
-                AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
-                    panic!("invalid allocator output")
+                AllocatorTy::Never | AllocatorTy::ResultPtr | AllocatorTy::Unit => {
+                    panic!("invalid allocator arg")
                 }
-            };
-            let from_name = mangle_internal_symbol(tcx, &global_fn_name(method.name));
-            let to_name = mangle_internal_symbol(tcx, &default_fn_name(method.name));
-
-            create_wrapper_function(tcx, context, &from_name, Some(&to_name), &types, output);
+            }
         }
-    }
+        let output = match method.output {
+            AllocatorTy::ResultPtr => Some(i8p),
+            AllocatorTy::Never | AllocatorTy::Unit => None,
 
-    // FIXME(bjorn3): Add noreturn attribute
-    create_wrapper_function(
-        tcx,
-        context,
-        &mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
-        Some(&mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind))),
-        &[usize, usize],
-        None,
-    );
+            AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
+                panic!("invalid allocator output")
+            }
+        };
+        let from_name = mangle_internal_symbol(tcx, &global_fn_name(method.name));
+        let to_name = mangle_internal_symbol(tcx, &default_fn_name(method.name));
+
+        create_wrapper_function(tcx, context, &from_name, Some(&to_name), &types, output);
+    }
 
     create_const_value_function(
         tcx,