Port #![no_builtins] to the attribute parser.

compiler/rustc_attr_parsing/src/attributes/crate_level.rs

@@ -211,3 +211,12 @@ impl<S: Stage> NoArgsAttributeParser<S> for ProfilerRuntimeParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::ProfilerRuntime;
 }
+
+pub(crate) struct NoBuiltinsParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for NoBuiltinsParser {
+    const PATH: &[Symbol] = &[sym::no_builtins];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::NoBuiltins;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -28,9 +28,10 @@ use crate::attributes::codegen_attrs::{
 };
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::crate_level::{
-    CrateNameParser, MoveSizeLimitParser, NeedsPanicRuntimeParser, NoCoreParser, NoMainParser, NoStdParser,
-    PanicRuntimeParser, PatternComplexityLimitParser, ProfilerRuntimeParser, RecursionLimitParser,
-    RustcCoherenceIsCoreParser, TypeLengthLimitParser, WindowsSubsystemParser,
+    CrateNameParser, MoveSizeLimitParser, NeedsPanicRuntimeParser, NoBuiltinsParser, NoCoreParser,
+    NoMainParser, NoStdParser, PanicRuntimeParser, PatternComplexityLimitParser,
+    ProfilerRuntimeParser, RecursionLimitParser, RustcCoherenceIsCoreParser, TypeLengthLimitParser,
+    WindowsSubsystemParser,
 };
 use crate::attributes::debugger::DebuggerViualizerParser;
 use crate::attributes::deprecation::DeprecationParser;
@@ -269,6 +270,7 @@ attribute_parsers!(
         Single<WithoutArgs<MayDangleParser>>,
         Single<WithoutArgs<NeedsAllocatorParser>>,
         Single<WithoutArgs<NeedsPanicRuntimeParser>>,
+        Single<WithoutArgs<NoBuiltinsParser>>,
         Single<WithoutArgs<NoCoreParser>>,
         Single<WithoutArgs<NoImplicitPreludeParser>>,
         Single<WithoutArgs<NoLinkParser>>,

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -6,7 +6,6 @@ use std::sync::mpsc::{Receiver, Sender, channel};
 use std::{fs, io, mem, str, thread};
 
 use rustc_abi::Size;
-use rustc_ast::attr;
 use rustc_data_structures::assert_matches;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::jobserver::{self, Acquired};
@@ -19,6 +18,8 @@ use rustc_errors::{
     Level, MultiSpan, Style, Suggestions, catch_fatal_errors,
 };
 use rustc_fs_util::link_or_copy;
+use rustc_hir::attrs::AttributeKind;
+use rustc_hir::find_attr;
 use rustc_incremental::{
     copy_cgu_workproduct_to_incr_comp_cache_dir, in_incr_comp_dir, in_incr_comp_dir_sess,
 };
@@ -31,7 +32,7 @@ use rustc_session::config::{
     self, CrateType, Lto, OutFileName, OutputFilenames, OutputType, Passes, SwitchWithOptPath,
 };
 use rustc_span::source_map::SourceMap;
-use rustc_span::{FileName, InnerSpan, Span, SpanData, sym};
+use rustc_span::{FileName, InnerSpan, Span, SpanData};
 use rustc_target::spec::{MergeFunctions, SanitizerSet};
 use tracing::debug;
 
@@ -453,7 +454,7 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
     let (coordinator_send, coordinator_receive) = channel();
 
     let crate_attrs = tcx.hir_attrs(rustc_hir::CRATE_HIR_ID);
-    let no_builtins = attr::contains_name(crate_attrs, sym::no_builtins);
+    let no_builtins = find_attr!(crate_attrs, AttributeKind::NoBuiltins);
 
     let crate_info = CrateInfo::new(tcx, target_cpu);
 

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -2,7 +2,7 @@ use std::str::FromStr;
 
 use rustc_abi::{Align, ExternAbi};
 use rustc_ast::expand::autodiff_attrs::{AutoDiffAttrs, DiffActivity, DiffMode};
-use rustc_ast::{LitKind, MetaItem, MetaItemInner, attr};
+use rustc_ast::{LitKind, MetaItem, MetaItemInner};
 use rustc_hir::attrs::{
     AttributeKind, EiiImplResolution, InlineAttr, Linkage, RtsanSetting, UsedBy,
 };
@@ -353,7 +353,7 @@ fn apply_overrides(tcx: TyCtxt<'_>, did: LocalDefId, codegen_fn_attrs: &mut Code
     // When `no_builtins` is applied at the crate level, we should add the
     // `no-builtins` attribute to each function to ensure it takes effect in LTO.
     let crate_attrs = tcx.hir_attrs(rustc_hir::CRATE_HIR_ID);
-    let no_builtins = attr::contains_name(crate_attrs, sym::no_builtins);
+    let no_builtins = find_attr!(crate_attrs, AttributeKind::NoBuiltins);
     if no_builtins {
         codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_BUILTINS;
     }

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -849,6 +849,9 @@ pub enum AttributeKind {
     /// Represents `#[needs_panic_runtime]`
     NeedsPanicRuntime,
 
+    /// Represents `#[no_builtins]`
+    NoBuiltins,
+
     /// Represents `#[no_core]`
     NoCore(Span),
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -78,6 +78,7 @@ impl AttributeKind {
             Naked(..) => No,
             NeedsAllocator => No,
             NeedsPanicRuntime => No,
+            NoBuiltins => Yes,
             NoCore(..) => No,
             NoImplicitPrelude(..) => No,
             NoLink => No,

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -744,7 +744,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 compiler_builtins: find_attr!(attrs, AttributeKind::CompilerBuiltins),
                 needs_allocator: find_attr!(attrs, AttributeKind::NeedsAllocator),
                 needs_panic_runtime: find_attr!(attrs, AttributeKind::NeedsPanicRuntime),
-                no_builtins: ast::attr::contains_name(attrs, sym::no_builtins),
+                no_builtins: find_attr!(attrs, AttributeKind::NoBuiltins),
                 panic_runtime: find_attr!(attrs, AttributeKind::PanicRuntime),
                 profiler_runtime: find_attr!(attrs, AttributeKind::ProfilerRuntime),
                 symbol_mangling_version: tcx.sess.opts.get_symbol_mangling_version(),

compiler/rustc_passes/src/check_attr.rs

@@ -303,6 +303,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::PanicRuntime
                     | AttributeKind::NeedsPanicRuntime
                     | AttributeKind::ProfilerRuntime
+                    | AttributeKind::NoBuiltins
                     | AttributeKind::ObjcClass { .. }
                     | AttributeKind::ObjcSelector { .. }
                     | AttributeKind::RustcCoherenceIsCore(..)
@@ -401,7 +402,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::rustc_no_implicit_bounds
                             | sym::test_runner
                             | sym::reexport_test_harness_main
-                            | sym::no_builtins
                             | sym::crate_type
                             | sym::rustc_preserve_ub_checks,
                             ..

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.rs

@@ -908,26 +908,26 @@ mod no_main_1 {
 
 #[no_builtins]
 //~^ WARN crate-level attribute should be an inner attribute
-//~| HELP add a `!`
 mod no_builtins {
+    //~^ NOTE: this attribute does not have an `!`, which means it is applied to this module
     mod inner { #![no_builtins] }
-    //~^ WARN crate-level attribute should be in the root module
+    //~^ WARN the `#![no_builtins]` attribute can only be used at the crate root
 
     #[no_builtins] fn f() { }
     //~^ WARN crate-level attribute should be an inner attribute
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this function
 
     #[no_builtins] struct S;
     //~^ WARN crate-level attribute should be an inner attribute
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this struct
 
     #[no_builtins] type T = S;
     //~^ WARN crate-level attribute should be an inner attribute
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this type alias
 
     #[no_builtins] impl S { }
     //~^ WARN crate-level attribute should be an inner attribute
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this implementation
 }
 
 #[recursion_limit="0200"]

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.stderr

@@ -240,17 +240,6 @@ help: add a `!`
 LL | #![feature(x0600)]
    |  +
 
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:909:1
-   |
-LL | #[no_builtins]
-   | ^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL | #![no_builtins]
-   |  +
-
 warning: attribute should be applied to an `extern` block with non-Rust ABI
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:71:1
    |
@@ -465,56 +454,6 @@ help: add a `!`
 LL |     #![feature(x0600)] impl S { }
    |      +
 
-warning: crate-level attribute should be in the root module
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:913:17
-   |
-LL |     mod inner { #![no_builtins] }
-   |                 ^^^^^^^^^^^^^^^
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:916:5
-   |
-LL |     #[no_builtins] fn f() { }
-   |     ^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![no_builtins] fn f() { }
-   |      +
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:920:5
-   |
-LL |     #[no_builtins] struct S;
-   |     ^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![no_builtins] struct S;
-   |      +
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:924:5
-   |
-LL |     #[no_builtins] type T = S;
-   |     ^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![no_builtins] type T = S;
-   |      +
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:928:5
-   |
-LL |     #[no_builtins] impl S { }
-   |     ^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![no_builtins] impl S { }
-   |      +
-
 warning: `#[macro_use]` attribute cannot be used on functions
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:190:5
    |
@@ -1416,6 +1355,76 @@ note: this attribute does not have an `!`, which means it is applied to this imp
 LL |     #[no_main] impl S { }
    |                ^^^^^^^^^^
 
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![no_builtins]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:909:1
+   |
+LL | #[no_builtins]
+   | ^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this module
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:911:1
+   |
+LL | / mod no_builtins {
+LL | |
+LL | |     mod inner { #![no_builtins] }
+...  |
+LL | | }
+   | |_^
+
+warning: the `#![no_builtins]` attribute can only be used at the crate root
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:913:17
+   |
+LL |     mod inner { #![no_builtins] }
+   |                 ^^^^^^^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![no_builtins]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:916:5
+   |
+LL |     #[no_builtins] fn f() { }
+   |     ^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this function
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:916:20
+   |
+LL |     #[no_builtins] fn f() { }
+   |                    ^^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![no_builtins]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:920:5
+   |
+LL |     #[no_builtins] struct S;
+   |     ^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this struct
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:920:20
+   |
+LL |     #[no_builtins] struct S;
+   |                    ^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![no_builtins]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:924:5
+   |
+LL |     #[no_builtins] type T = S;
+   |     ^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this type alias
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:924:20
+   |
+LL |     #[no_builtins] type T = S;
+   |                    ^^^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![no_builtins]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:928:5
+   |
+LL |     #[no_builtins] impl S { }
+   |     ^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this implementation block
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:928:20
+   |
+LL |     #[no_builtins] impl S { }
+   |                    ^^^^^^^^^^
+
 warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![recursion_limit]`
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:933:1
    |

tests/ui/lint/unused/unused-attr-duplicate.stderr

@@ -16,18 +16,6 @@ note: the lint level is defined here
 LL | #![deny(unused_attributes)]
    |         ^^^^^^^^^^^^^^^^^
 
-error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:34:1
-   |
-LL | #![no_builtins]
-   | ^^^^^^^^^^^^^^^ help: remove this attribute
-   |
-note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:33:1
-   |
-LL | #![no_builtins]
-   | ^^^^^^^^^^^^^^^
-
 error: unused attribute
   --> $DIR/unused-attr-duplicate.rs:37:1
    |
@@ -316,5 +304,17 @@ LL | #![windows_subsystem = "console"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
+error: unused attribute
+  --> $DIR/unused-attr-duplicate.rs:34:1
+   |
+LL | #![no_builtins]
+   | ^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+note: attribute also specified here
+  --> $DIR/unused-attr-duplicate.rs:33:1
+   |
+LL | #![no_builtins]
+   | ^^^^^^^^^^^^^^^
+
 error: aborting due to 25 previous errors