Update logic

Author: chansuke

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -1,24 +1,24 @@
-use rustc_ast::{MetaItemInner, MetaItemKind, ast, attr};
-use rustc_attr::{InlineAttr, InstructionSetAttr, OptimizeAttr, list_contains_name};
+use rustc_ast::{ast, attr, MetaItemInner, MetaItemKind};
+use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::codes::*;
-use rustc_errors::{DiagMessage, SubdiagMessage, struct_span_code_err};
+use rustc_errors::{struct_span_code_err, DiagMessage, SubdiagMessage};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId};
+use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
 use rustc_hir::weak_lang_items::WEAK_LANG_ITEMS;
-use rustc_hir::{LangItem, lang_items};
+use rustc_hir::{lang_items, LangItem};
 use rustc_middle::middle::codegen_fn_attrs::{
     CodegenFnAttrFlags, CodegenFnAttrs, PatchableFunctionEntry,
 };
 use rustc_middle::mir::mono::Linkage;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self as ty, TyCtxt};
 use rustc_session::parse::feature_err;
-use rustc_session::{Session, lint};
+use rustc_session::{lint, Session};
 use rustc_span::symbol::Ident;
-use rustc_span::{Span, sym};
-use rustc_target::spec::{SanitizerSet, abi};
+use rustc_span::{sym, Span};
+use rustc_target::spec::{abi, SanitizerSet};
 
 use crate::errors;
 use crate::target_features::{check_target_feature_trait_unsafe, from_target_feature_attr};
@@ -376,10 +376,29 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                                         Some(InstructionSetAttr::ArmA32)
                                     } else if segments[1] == sym::t32 {
                                         Some(InstructionSetAttr::ArmT32)
+                                    } else if segments[1] != sym::a32 || segments[1] != sym::t32 {
+                                        struct_span_code_err!(
+                                            tcx.dcx(),
+                                            attr.span,
+                                            E0779,
+                                            "`[instruction_set]` attribute argument should be valid"
+                                        )
+                                        .emit();
+                                        None
                                     } else {
                                         unreachable!()
                                     }
                                 }
+                                [] => {
+                                    struct_span_code_err!(
+                                        tcx.dcx(),
+                                        attr.span,
+                                        E0778,
+                                        "`[instruction_set]` requires an argument"
+                                    )
+                                    .emit();
+                                    None
+                                }
                                 _ => None,
                             }
                         }