6 files changed, 17 insertions, 16 deletions
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 4dcc7cd5447..a22a67ad7d3 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -3,7 +3,6 @@ use crate::back::write::to_llvm_code_model;
 use crate::callee::get_fn;
 use crate::coverageinfo;
 use crate::debuginfo;
-use crate::errors::BranchProtectionRequiresAArch64;
 use crate::llvm;
 use crate::llvm_util;
 use crate::type_::Type;
@@ -275,10 +274,9 @@ pub unsafe fn create_module<'ll>(
         }
     }
 
-    if let Some(BranchProtection { bti, pac_ret }) = sess.opts.unstable_opts.branch_protection {
-        if sess.target.arch != "aarch64" {
-            sess.emit_err(BranchProtectionRequiresAArch64);
-        } else {
+    // AArch64-only options (checked in rustc_session).
+    if sess.target.arch == "aarch64" {
+        if let Some(BranchProtection { bti, pac_ret }) = sess.opts.unstable_opts.branch_protection {
             llvm::LLVMRustAddModuleFlag(
                 llmod,
                 llvm::LLVMModFlagBehavior::Error,
diff --git a/compiler/rustc_codegen_llvm/src/errors.rs b/compiler/rustc_codegen_llvm/src/errors.rs
index fddfbb23c67..de508f917f3 100644
--- a/compiler/rustc_codegen_llvm/src/errors.rs
+++ b/compiler/rustc_codegen_llvm/src/errors.rs
@@ -52,10 +52,6 @@ pub(crate) struct SymbolAlreadyDefined<'a> {
 }
 
 #[derive(Diagnostic)]
-#[diag(codegen_llvm_branch_protection_requires_aarch64)]
-pub(crate) struct BranchProtectionRequiresAArch64;
-
-#[derive(Diagnostic)]
 #[diag(codegen_llvm_invalid_minimum_alignment)]
 pub(crate) struct InvalidMinimumAlignment {
     pub err: String,
diff --git a/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl b/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
index e273476b60b..86f71a611ab 100644
--- a/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
@@ -17,9 +17,6 @@ codegen_llvm_instrument_coverage_requires_llvm_12 =
 codegen_llvm_symbol_already_defined =
     symbol `{$symbol_name}` is already defined
 
-codegen_llvm_branch_protection_requires_aarch64 =
-    -Zbranch-protection is only supported on aarch64
-
 codegen_llvm_invalid_minimum_alignment =
     invalid minimum global alignment: {$err}
 
diff --git a/compiler/rustc_error_messages/locales/en-US/session.ftl b/compiler/rustc_error_messages/locales/en-US/session.ftl
index 983eb926213..ab9e8b6baae 100644
--- a/compiler/rustc_error_messages/locales/en-US/session.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/session.ftl
@@ -41,6 +41,8 @@ session_unsupported_dwarf_version = requested DWARF version {$dwarf_version} is
 
 session_target_stack_protector_not_supported = `-Z stack-protector={$stack_protector}` is not supported for target {$target_triple} and will be ignored
 
+session_branch_protection_requires_aarch64 = `-Zbranch-protection` is only supported on aarch64
+
 session_split_debuginfo_unstable_platform = `-Csplit-debuginfo={$debuginfo}` is unstable on this platform
 
 session_file_is_not_writeable = output file {$file} is not writeable -- check its permissions
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 8cb9e1a6f1a..fd7dabf75ef 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -116,6 +116,10 @@ pub struct StackProtectorNotSupportedForTarget<'a> {
 }
 
 #[derive(Diagnostic)]
+#[diag(session_branch_protection_requires_aarch64)]
+pub(crate) struct BranchProtectionRequiresAArch64;
+
+#[derive(Diagnostic)]
 #[diag(session_split_debuginfo_unstable_platform)]
 pub struct SplitDebugInfoUnstablePlatform {
     pub debuginfo: SplitDebuginfo,
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index e99e460913e..ce4a2e3d82d 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -3,10 +3,10 @@ use crate::code_stats::CodeStats;
 pub use crate::code_stats::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
 use crate::config::{self, CrateType, InstrumentCoverage, OptLevel, OutputType, SwitchWithOptPath};
 use crate::errors::{
-    CannotEnableCrtStaticLinux, CannotMixAndMatchSanitizers, LinkerPluginToWindowsNotSupported,
-    NotCircumventFeature, ProfileSampleUseFileDoesNotExist, ProfileUseFileDoesNotExist,
-    SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported, SkippingConstChecks,
-    SplitDebugInfoUnstablePlatform, StackProtectorNotSupportedForTarget,
+    BranchProtectionRequiresAArch64, CannotEnableCrtStaticLinux, CannotMixAndMatchSanitizers,
+    LinkerPluginToWindowsNotSupported, NotCircumventFeature, ProfileSampleUseFileDoesNotExist,
+    ProfileUseFileDoesNotExist, SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported,
+    SkippingConstChecks, SplitDebugInfoUnstablePlatform, StackProtectorNotSupportedForTarget,
     TargetRequiresUnwindTables, UnleashedFeatureHelp, UnstableVirtualFunctionElimination,
     UnsupportedDwarfVersion,
 };
@@ -1542,6 +1542,10 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
         }
     }
 
+    if sess.opts.unstable_opts.branch_protection.is_some() && sess.target.arch != "aarch64" {
+        sess.emit_err(BranchProtectionRequiresAArch64);
+    }
+
     if let Some(dwarf_version) = sess.opts.unstable_opts.dwarf_version {
         if dwarf_version > 5 {
             sess.emit_err(UnsupportedDwarfVersion { dwarf_version });