Port #[instruction_set] to attribute parser

Author: Bryntet

compiler/rustc_attr_parsing/messages.ftl

@@ -229,6 +229,8 @@ attr_parsing_unstable_cfg_target_compact =
 attr_parsing_unstable_feature_bound_incompatible_stability = item annotated with `#[unstable_feature_bound]` should not be stable
     .help = If this item is meant to be stable, do not use any functions annotated with `#[unstable_feature_bound]`. Otherwise, mark this item as unstable with `#[unstable]`
 
+attr_parsing_unsupported_instruction_set = target `{$current_target}` does not support `#[instruction_set({$instruction_set}::*)]`
+
 attr_parsing_unsupported_literal_suggestion =
     consider removing the prefix
 

compiler/rustc_attr_parsing/src/attributes/instruction_set.rs

@@ -0,0 +1,67 @@
+use rustc_hir::attrs::InstructionSetAttr;
+
+use super::prelude::*;
+use crate::session_diagnostics;
+
+pub(crate) struct InstructionSetParser;
+
+impl<S: Stage> SingleAttributeParser<S> for InstructionSetParser {
+    const PATH: &[Symbol] = &[sym::instruction_set];
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
+    const TEMPLATE: AttributeTemplate = template!(List: &["set"], "https://doc.rust-lang.org/reference/attributes/codegen.html#the-instruction_set-attribute");
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+        const POSSIBLE_SYMBOLS: &[Symbol] = &[sym::arm_a32, sym::arm_t32];
+        const POSSIBLE_ARM_SYMBOLS: &[Symbol] = &[sym::a32, sym::t32];
+        let Some(maybe_meta_item) = args.list().and_then(MetaItemListParser::single) else {
+            cx.expected_specific_argument(cx.attr_span, POSSIBLE_SYMBOLS);
+            return None;
+        };
+
+        let Some(meta_item) = maybe_meta_item.meta_item() else {
+            cx.expected_specific_argument(maybe_meta_item.span(), POSSIBLE_SYMBOLS);
+            return None;
+        };
+
+        let mut segments = meta_item.path().segments();
+
+        let Some(architecture) = segments.next() else {
+            cx.expected_specific_argument(meta_item.span(), POSSIBLE_SYMBOLS);
+            return None;
+        };
+
+        let Some(instruction_set) = segments.next() else {
+            cx.expected_specific_argument(architecture.span, POSSIBLE_SYMBOLS);
+            return None;
+        };
+
+        let instruction_set = match architecture.name {
+            sym::arm => {
+                if !cx.sess.target.has_thumb_interworking {
+                    cx.dcx().emit_err(session_diagnostics::UnsupportedInstructionSet {
+                        span: cx.attr_span,
+                        instruction_set: sym::arm,
+                        current_target: &cx.sess.opts.target_triple,
+                    });
+                    return None;
+                }
+                match instruction_set.name {
+                    sym::a32 => InstructionSetAttr::ArmA32,
+                    sym::t32 => InstructionSetAttr::ArmT32,
+                    _ => {
+                        cx.expected_specific_argument(instruction_set.span, POSSIBLE_ARM_SYMBOLS);
+                        return None;
+                    }
+                }
+            }
+            _ => {
+                cx.expected_specific_argument(architecture.span, POSSIBLE_SYMBOLS);
+                return None;
+            }
+        };
+
+        Some(AttributeKind::InstructionSet(instruction_set))
+    }
+}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -41,6 +41,7 @@ pub(crate) mod deprecation;
 pub(crate) mod doc;
 pub(crate) mod dummy;
 pub(crate) mod inline;
+pub(crate) mod instruction_set;
 pub(crate) mod link_attrs;
 pub(crate) mod lint_helpers;
 pub(crate) mod loop_match;

compiler/rustc_attr_parsing/src/context.rs

@@ -36,6 +36,7 @@ use crate::attributes::deprecation::DeprecationParser;
 use crate::attributes::doc::DocParser;
 use crate::attributes::dummy::DummyParser;
 use crate::attributes::inline::{InlineParser, RustcForceInlineParser};
+use crate::attributes::instruction_set::InstructionSetParser;
 use crate::attributes::link_attrs::{
     ExportStableParser, FfiConstParser, FfiPureParser, LinkNameParser, LinkOrdinalParser,
     LinkParser, LinkSectionParser, LinkageParser, StdInternalSymbolParser,
@@ -194,6 +195,7 @@ attribute_parsers!(
         Single<ExportNameParser>,
         Single<IgnoreParser>,
         Single<InlineParser>,
+        Single<InstructionSetParser>,
         Single<LinkNameParser>,
         Single<LinkOrdinalParser>,
         Single<LinkSectionParser>,

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -9,6 +9,7 @@ use rustc_feature::AttributeTemplate;
 use rustc_hir::AttrPath;
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
+use rustc_target::spec::TargetTuple;
 
 use crate::fluent_generated as fluent;
 
@@ -926,3 +927,12 @@ pub(crate) struct DocAliasMalformed {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_unsupported_instruction_set)]
+pub(crate) struct UnsupportedInstructionSet<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub instruction_set: Symbol,
+    pub current_target: &'a TargetTuple,
+}

compiler/rustc_codegen_ssa/messages.ftl

@@ -8,8 +8,6 @@ codegen_ssa_aix_strip_not_used = using host's `strip` binary to cross-compile to
 
 codegen_ssa_archive_build_failure = failed to build archive at `{$path}`: {$error}
 
-codegen_ssa_bare_instruction_set = `#[instruction_set]` requires an argument
-
 codegen_ssa_binary_output_to_tty = option `-o` or `--emit` is used to write binary output type `{$shorthand}` to stdout, but stdout is a tty
 
 codegen_ssa_cgu_not_recorded =
@@ -90,8 +88,6 @@ codegen_ssa_incorrect_cgu_reuse_type =
 
 codegen_ssa_insufficient_vs_code_product = VS Code is a different product, and is not sufficient.
 
-codegen_ssa_invalid_instruction_set = invalid instruction set specified
-
 codegen_ssa_invalid_literal_value = invalid literal value
     .label = value must be an integer between `0` and `255`
 
@@ -215,8 +211,6 @@ codegen_ssa_msvc_missing_linker = the msvc targets depend on the msvc linker but
 
 codegen_ssa_multiple_external_func_decl = multiple declarations of external function `{$function}` from library `{$library_name}` have different calling conventions
 
-codegen_ssa_multiple_instruction_set = cannot specify more than one instruction set
-
 codegen_ssa_multiple_main_functions = entry symbol `main` declared multiple times
     .help = did you use `#[no_mangle]` on `fn main`? Use `#![no_main]` to suppress the usual Rust-generated entry point
 
@@ -383,8 +377,6 @@ codegen_ssa_unstable_ctarget_feature =
     unstable feature specified for `-Ctarget-feature`: `{$feature}`
     .note = this feature is not stably supported; its behavior can change in the future
 
-codegen_ssa_unsupported_instruction_set = target does not support `#[instruction_set]`
-
 codegen_ssa_unsupported_link_self_contained = option `-C link-self-contained` is not supported on this target
 
 codegen_ssa_use_cargo_directive = use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#rustc-link-lib)

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -3,9 +3,7 @@ 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_hir::attrs::{
-    AttributeKind, InlineAttr, InstructionSetAttr, Linkage, RtsanSetting, UsedBy,
-};
+use rustc_hir::attrs::{AttributeKind, InlineAttr, Linkage, RtsanSetting, UsedBy};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId};
 use rustc_hir::{self as hir, Attribute, LangItem, find_attr, lang_items};
@@ -47,37 +45,6 @@ fn try_fn_sig<'tcx>(
     }
 }
 
-// FIXME(jdonszelmann): remove when instruction_set becomes a parsed attr
-fn parse_instruction_set_attr(tcx: TyCtxt<'_>, attr: &Attribute) -> Option<InstructionSetAttr> {
-    let list = attr.meta_item_list()?;
-
-    match &list[..] {
-        [MetaItemInner::MetaItem(set)] => {
-            let segments = set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>();
-            match segments.as_slice() {
-                [sym::arm, sym::a32 | sym::t32] if !tcx.sess.target.has_thumb_interworking => {
-                    tcx.dcx().emit_err(errors::UnsupportedInstructionSet { span: attr.span() });
-                    None
-                }
-                [sym::arm, sym::a32] => Some(InstructionSetAttr::ArmA32),
-                [sym::arm, sym::t32] => Some(InstructionSetAttr::ArmT32),
-                _ => {
-                    tcx.dcx().emit_err(errors::InvalidInstructionSet { span: attr.span() });
-                    None
-                }
-            }
-        }
-        [] => {
-            tcx.dcx().emit_err(errors::BareInstructionSet { span: attr.span() });
-            None
-        }
-        _ => {
-            tcx.dcx().emit_err(errors::MultipleInstructionSet { span: attr.span() });
-            None
-        }
-    }
-}
-
 // FIXME(jdonszelmann): remove when patchable_function_entry becomes a parsed attr
 fn parse_patchable_function_entry(
     tcx: TyCtxt<'_>,
@@ -350,6 +317,9 @@ fn process_builtin_attrs(
                         codegen_fn_attrs.flags |= CodegenFnAttrFlags::EXTERNALLY_IMPLEMENTABLE_ITEM;
                     }
                 }
+                AttributeKind::InstructionSet(instruction_set) => {
+                    codegen_fn_attrs.instruction_set = Some(*instruction_set)
+                }
                 _ => {}
             }
         }
@@ -367,9 +337,6 @@ fn process_builtin_attrs(
                 codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR_ZEROED
             }
             sym::thread_local => codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL,
-            sym::instruction_set => {
-                codegen_fn_attrs.instruction_set = parse_instruction_set_attr(tcx, attr)
-            }
             sym::patchable_function_entry => {
                 codegen_fn_attrs.patchable_function_entry =
                     parse_patchable_function_entry(tcx, attr);

compiler/rustc_codegen_ssa/src/errors.rs

@@ -136,34 +136,6 @@ pub(crate) struct RequiresRustAbi {
     pub span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_unsupported_instruction_set, code = E0779)]
-pub(crate) struct UnsupportedInstructionSet {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_invalid_instruction_set, code = E0779)]
-pub(crate) struct InvalidInstructionSet {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_bare_instruction_set, code = E0778)]
-pub(crate) struct BareInstructionSet {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_multiple_instruction_set, code = E0779)]
-pub(crate) struct MultipleInstructionSet {
-    #[primary_span]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_expected_name_value_pair)]
 pub(crate) struct ExpectedNameValuePair {

compiler/rustc_error_codes/src/error_codes/E0778.md

@@ -1,15 +1,6 @@
+#### Note: this error code is no longer emitted by the compiler
 The `instruction_set` attribute was malformed.
 
-Erroneous code example:
-
-```compile_fail,E0778
-#![feature(isa_attribute)]
-
-#[instruction_set()] // error: expected one argument
-pub fn something() {}
-fn main() {}
-```
-
 The parenthesized `instruction_set` attribute requires the parameter to be
 specified:
 

compiler/rustc_error_codes/src/error_codes/E0779.md

@@ -1,14 +1,6 @@
+#### Note: this error code is no longer emitted by the compiler
 An unknown argument was given to the `instruction_set` attribute.
 
-Erroneous code example:
-
-```compile_fail,E0779
-#![feature(isa_attribute)]
-
-#[instruction_set(intel::x64)] // error: invalid argument
-pub fn something() {}
-fn main() {}
-```
 
 The `instruction_set` attribute only supports two arguments currently: