Auto merge of #2738 - RalfJung:rustup, r=RalfJung

Rustup

1 files changed, 15 insertions, 7 deletions

diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index aa1735f38ac..d9ccba07a34 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;
@@ -281,34 +280,43 @@ 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);
+        let behavior = if llvm_version >= (15, 0, 0) {
+            llvm::LLVMModFlagBehavior::Min
         } else {
+            llvm::LLVMModFlagBehavior::Error
+        };
+
+        if sess.target.arch == "aarch64" {
             llvm::LLVMRustAddModuleFlag(
                 llmod,
-                llvm::LLVMModFlagBehavior::Error,
+                behavior,
                 "branch-target-enforcement\0".as_ptr().cast(),
                 bti.into(),
             );
             llvm::LLVMRustAddModuleFlag(
                 llmod,
-                llvm::LLVMModFlagBehavior::Error,
+                behavior,
                 "sign-return-address\0".as_ptr().cast(),
                 pac_ret.is_some().into(),
             );
             let pac_opts = pac_ret.unwrap_or(PacRet { leaf: false, key: PAuthKey::A });
             llvm::LLVMRustAddModuleFlag(
                 llmod,
-                llvm::LLVMModFlagBehavior::Error,
+                behavior,
                 "sign-return-address-all\0".as_ptr().cast(),
                 pac_opts.leaf.into(),
             );
             llvm::LLVMRustAddModuleFlag(
                 llmod,
-                llvm::LLVMModFlagBehavior::Error,
+                behavior,
                 "sign-return-address-with-bkey\0".as_ptr().cast(),
                 u32::from(pac_opts.key == PAuthKey::B),
             );
+        } else {
+            bug!(
+                "branch-protection used on non-AArch64 target; \
+                  this should be checked in rustc_session."
+            );
         }
     }