[Clang][ARM][AArch64] Alway emit protection attributes for functions. (…

…llvm#82819) So far branch protection, sign return address, guarded control stack attributes are only emitted as module flags to indicate the functions need to be generated with those features. The problem is in case of an LTO build the module flags are merged with the `min` rule which means if one of the module is not build with sign return address then the features will be turned off for all functions. Due to the functions take the branch-protection and sign-return-address features from the module flags. The sign-return-address is function level option therefore it is expected functions from files that is compiled with -mbranch-protection=pac-ret to be protected. The inliner might inline functions with different set of flags as it doesn't consider the module flags. This patch adds the attributes to all functions and drops the checking of the module flags for the code generation. Module flag is still used for generating the ELF markers. Also drops the "true"/"false" values from the branch-protection-enforcement, branch-protection-pauth-lr, guarded-control-stack attributes as presence of the attribute means it is on absence means off and no other option.
aaryanshukla · Jul 14, 2024 · b665667 · b665667
1 parent ad595c1
commit b665667
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Showing 60 changed files with 292 additions and 316 deletions.
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
@@ -32,7 +32,9 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Frontend/OpenMP/OMPGridValues.h"
+#include "llvm/IR/Attributes.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/VersionTuple.h"
@@ -1400,15 +1402,15 @@ class TargetInfo : public TransferrableTargetInfo,
     return true;
   }
 
-  struct BranchProtectionInfo {
+  class BranchProtectionInfo {
+  public:
     LangOptions::SignReturnAddressScopeKind SignReturnAddr;
     LangOptions::SignReturnAddressKeyKind SignKey;
     bool BranchTargetEnforcement;
     bool BranchProtectionPAuthLR;
     bool GuardedControlStack;
 
-    BranchProtectionInfo() = default;
-
+  protected:
     const char *getSignReturnAddrStr() const {
       switch (SignReturnAddr) {
       case LangOptions::SignReturnAddressScopeKind::None:
@@ -1430,6 +1432,42 @@ class TargetInfo : public TransferrableTargetInfo,
       }
       llvm_unreachable("Unexpected SignReturnAddressKeyKind");
     }
+
+  public:
+    BranchProtectionInfo() = default;
+    BranchProtectionInfo(const LangOptions &LangOpts) {
+      SignReturnAddr =
+          LangOpts.hasSignReturnAddress()
+              ? (LangOpts.isSignReturnAddressScopeAll()
+                     ? LangOptions::SignReturnAddressScopeKind::All
+                     : LangOptions::SignReturnAddressScopeKind::NonLeaf)
+              : LangOptions::SignReturnAddressScopeKind::None;
+      SignKey = LangOpts.isSignReturnAddressWithAKey()
+                    ? LangOptions::SignReturnAddressKeyKind::AKey
+                    : LangOptions::SignReturnAddressKeyKind::BKey;
+      BranchTargetEnforcement = LangOpts.BranchTargetEnforcement;
+      BranchProtectionPAuthLR = LangOpts.BranchProtectionPAuthLR;
+      GuardedControlStack = LangOpts.GuardedControlStack;
+    }
+
+    void setFnAttributes(llvm::Function &F) {
+      llvm::AttrBuilder FuncAttrs(F.getContext());
+      setFnAttributes(FuncAttrs);
+      F.addFnAttrs(FuncAttrs);
+    }
+
+    void setFnAttributes(llvm::AttrBuilder &FuncAttrs) {
+      if (SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
+        FuncAttrs.addAttribute("sign-return-address", getSignReturnAddrStr());
+        FuncAttrs.addAttribute("sign-return-address-key", getSignKeyStr());
+      }
+      if (BranchTargetEnforcement)
+        FuncAttrs.addAttribute("branch-target-enforcement");
+      if (BranchProtectionPAuthLR)
+        FuncAttrs.addAttribute("branch-protection-pauth-lr");
+      if (GuardedControlStack)
+        FuncAttrs.addAttribute("guarded-control-stack");
+    }
   };
 
   /// Determine if the Architecture in this TargetInfo supports branch

diff --git a/clang/lib/CodeGen/Targets/AArch64.cpp b/clang/lib/CodeGen/Targets/AArch64.cpp
@@ -120,37 +120,20 @@ class AArch64TargetCodeGenInfo : public TargetCodeGenInfo {
     if (!FD)
       return;
 
-    const auto *TA = FD->getAttr<TargetAttr>();
-    if (TA == nullptr)
-      return;
-
-    ParsedTargetAttr Attr =
-        CGM.getTarget().parseTargetAttr(TA->getFeaturesStr());
-    if (Attr.BranchProtection.empty())
-      return;
-
-    TargetInfo::BranchProtectionInfo BPI;
-    StringRef Error;
-    (void)CGM.getTarget().validateBranchProtection(Attr.BranchProtection,
-                                                   Attr.CPU, BPI, Error);
-    assert(Error.empty());
-
-    auto *Fn = cast<llvm::Function>(GV);
-    Fn->addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());
-
-    if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
-      Fn->addFnAttr("sign-return-address-key",
-                    BPI.SignKey == LangOptions::SignReturnAddressKeyKind::AKey
-                        ? "a_key"
-                        : "b_key");
+    TargetInfo::BranchProtectionInfo BPI(CGM.getLangOpts());
+
+    if (const auto *TA = FD->getAttr<TargetAttr>()) {
+      ParsedTargetAttr Attr =
+          CGM.getTarget().parseTargetAttr(TA->getFeaturesStr());
+      if (!Attr.BranchProtection.empty()) {
+        StringRef Error;
+        (void)CGM.getTarget().validateBranchProtection(Attr.BranchProtection,
+                                                       Attr.CPU, BPI, Error);
+        assert(Error.empty());
+      }
     }
-
-    Fn->addFnAttr("branch-target-enforcement",
-                  BPI.BranchTargetEnforcement ? "true" : "false");
-    Fn->addFnAttr("branch-protection-pauth-lr",
-                  BPI.BranchProtectionPAuthLR ? "true" : "false");
-    Fn->addFnAttr("guarded-control-stack",
-                  BPI.GuardedControlStack ? "true" : "false");
+    auto *Fn = cast<llvm::Function>(GV);
+    BPI.setFnAttributes(*Fn);
   }
 
   bool isScalarizableAsmOperand(CodeGen::CodeGenFunction &CGF,

diff --git a/clang/lib/CodeGen/Targets/ARM.cpp b/clang/lib/CodeGen/Targets/ARM.cpp
@@ -152,9 +152,7 @@ class ARMTargetCodeGenInfo : public TargetCodeGenInfo {
               diag::warn_target_unsupported_branch_protection_attribute)
               << Arch;
         } else {
-          Fn->addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());
-          Fn->addFnAttr("branch-target-enforcement",
-                        BPI.BranchTargetEnforcement ? "true" : "false");
+          BPI.setFnAttributes(*Fn);
         }
       } else if (CGM.getLangOpts().BranchTargetEnforcement ||
                  CGM.getLangOpts().hasSignReturnAddress()) {
@@ -167,6 +165,10 @@ class ARMTargetCodeGenInfo : public TargetCodeGenInfo {
               diag::warn_target_unsupported_branch_protection_attribute)
               << Attr.CPU;
       }
+    } else if (CGM.getTarget().isBranchProtectionSupportedArch(
+                   CGM.getTarget().getTargetOpts().CPU)) {
+      TargetInfo::BranchProtectionInfo BPI(CGM.getLangOpts());
+      BPI.setFnAttributes(*Fn);
     }
 
     const ARMInterruptAttr *Attr = FD->getAttr<ARMInterruptAttr>();

diff --git a/clang/test/CodeGen/aarch64-branch-protection-attr.c b/clang/test/CodeGen/aarch64-branch-protection-attr.c
@@ -67,29 +67,29 @@ __attribute__ ((target("branch-protection=gcs")))
 void gcs() {}
 // CHECK: define{{.*}} void @gcs() #[[#GCS:]]
 
-// CHECK-DAG: attributes #[[#NONE]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#NONE]] = { {{.*}}
 
-// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="true" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement" "guarded-control-stack" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
 
-// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"
 
-// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
 
-// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "sign-return-address"="all" "sign-return-address-key"="a_key"
 
-// CHECK-DAG: attributes #[[#PACBKEY]] = { {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
+// CHECK-DAG: attributes #[[#PACBKEY]] = { {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
 
-// CHECK-DAG: attributes #[[#PACBKEYLEAF]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="b_key"
+// CHECK-DAG: attributes #[[#PACBKEYLEAF]] = { {{.*}} "sign-return-address"="all" "sign-return-address-key"="b_key"
 
-// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}}"branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}} "sign-return-address"="all" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}} "branch-target-enforcement" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
 
 
-// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
 
-// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
+// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
 
-// CHECK-DAG: attributes #[[#PAUTHLR_LEAF]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAUTHLR_LEAF]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
 
-// CHECK-DAG: attributes #[[#PAUTHLR_BTI]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAUTHLR_BTI]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"branch-target-enforcement" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
 
-// CHECK-DAG: attributes #[[#GCS]] = { {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="true" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#GCS]] = { {{.*}} "guarded-control-stack"
diff --git a/clang/test/CodeGen/aarch64-sign-return-address.c b/clang/test/CodeGen/aarch64-sign-return-address.c
@@ -13,9 +13,15 @@
 
 // CHECK-LABEL: @foo() #[[#ATTR:]]
 
-// CHECK-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
-// CHECK-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
-// CHECK-NOT:  attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+// NONE-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
+// NONE-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
+// NONE-NOT:  attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+
+// ALL:   attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
+// PART:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"="a_key"
+// B-KEY: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"="b_key"
+// BTE:   attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+
 
 // Check module attributes
 

diff --git a/clang/test/CodeGen/arm-branch-protection-attr-1.c b/clang/test/CodeGen/arm-branch-protection-attr-1.c
@@ -29,14 +29,14 @@ __attribute__((target("branch-protection=pac-ret+leaf"))) void leaf() {}
 __attribute__((target("branch-protection=pac-ret+leaf+bti"))) void btileaf() {}
 // CHECK: define{{.*}} void @btileaf() #[[#BTIPACLEAF:]]
 
-// CHECK-DAG: attributes #[[#NONE]] = { {{.*}} "branch-target-enforcement"="false" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#NONE]] = { {{.*}}
 
-// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement"="true" {{.*}} "sign-return-address"="non-leaf"
+// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement" {{.*}} "sign-return-address"="non-leaf"
 
-// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"="true" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"
 
-// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "branch-target-enforcement"="false" {{.*}} "sign-return-address"="non-leaf"
+// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "sign-return-address"="non-leaf"
 
-// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "branch-target-enforcement"="false" {{.*}}"sign-return-address"="all"
+// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "sign-return-address"="all"
 
-// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}}"branch-target-enforcement"="true" {{.*}} "sign-return-address"="all"
+// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}} "branch-target-enforcement" {{.*}} "sign-return-address"="all"
diff --git a/clang/test/CodeGen/arm-branch-protection-attr-2.c b/clang/test/CodeGen/arm-branch-protection-attr-2.c
@@ -5,13 +5,18 @@
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -S -emit-llvm -o - -mbranch-protection=pac-ret+b-key %s | FileCheck %s --check-prefix=CHECK --check-prefix=PART
 // RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -S -emit-llvm -o - -mbranch-protection=bti %s           | FileCheck %s --check-prefix=CHECK --check-prefix=BTE
 
-// Check there are no branch protection function attributes
+// Check there are branch protection function attributes
 
 // CHECK-LABEL: @foo() #[[#ATTR:]]
 
-// CHECK-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
-// CHECK-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
-// CHECK-NOT:  attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+// NONE-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
+// NONE-NOT:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
+// NONE-NOT:  attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+
+// ALL:   attributes #[[#ATTR]] = { {{.*}} "sign-return-address"="all"
+// PART:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address"="non-leaf"
+// BTE:   attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+
 
 // Check module attributes
 

diff --git a/clang/test/Frontend/arm-branch-protection-lto.c b/clang/test/Frontend/arm-branch-protection-lto.c
@@ -0,0 +1,24 @@
+// REQUIRES: arm-registered-target
+
+// RUN: %clang_cc1 -triple=thumbv7m-unknown-unknown-eabi -msign-return-address=non-leaf %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=SIGN
+// RUN: %clang_cc1 -triple=thumbv7m-unknown-unknown-eabi -mbranch-target-enforce %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=BTE
+// RUN: %clang_cc1 -triple=thumbv7m-unknown-unknown-eabi -mbranch-target-enforce -msign-return-address=all %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=ALL
+
+// RUN: %clang_cc1 -flto -triple=thumbv7m-unknown-unknown-eabi -msign-return-address=non-leaf %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=SIGN
+// RUN: %clang_cc1 -flto -triple=thumbv7m-unknown-unknown-eabi -mbranch-target-enforce %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=BTE
+// RUN: %clang_cc1 -flto -triple=thumbv7m-unknown-unknown-eabi -mbranch-target-enforce -msign-return-address=all %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=ALL
+
+// RUN: %clang_cc1 -flto=thin -triple=thumbv7m-unknown-unknown-eabi -msign-return-address=non-leaf %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=SIGN
+// RUN: %clang_cc1 -flto=thin -triple=thumbv7m-unknown-unknown-eabi -mbranch-target-enforce  %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=BTE
+// RUN: %clang_cc1 -flto=thin -triple=thumbv7m-unknown-unknown-eabi -mbranch-target-enforce -msign-return-address=all %s -emit-llvm -o - 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=ALL
+
+void foo() {}
+
+// Check there are branch protection function attributes.
+// CHECK-LABEL: @foo() #[[#ATTR:]]
+
+// SIGN-NOT: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+// SIGN: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"="non-leaf"
+// BTE:  attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
+// BTE:  attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"
+// ALL:  attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"{{.*}} "sign-return-address"="all"
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -12012,17 +12012,7 @@ void SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
         // table branch.
         if (FallthroughUnreachable) {
           Function &CurFunc = CurMF->getFunction();
-          bool HasBranchTargetEnforcement = false;
-          if (CurFunc.hasFnAttribute("branch-target-enforcement")) {
-            HasBranchTargetEnforcement =
-                CurFunc.getFnAttribute("branch-target-enforcement")
-                    .getValueAsBool();
-          } else {
-            HasBranchTargetEnforcement =
-                CurMF->getMMI().getModule()->getModuleFlag(
-                    "branch-target-enforcement");
-          }
-          if (!HasBranchTargetEnforcement)
+          if (!CurFunc.hasFnAttribute("branch-target-enforcement"))
             JTH->FallthroughUnreachable = true;
         }
 

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
@@ -2348,15 +2348,33 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
     if (S != "a_key" && S != "b_key")
       CheckFailed("invalid value for 'sign-return-address-key' attribute: " + S,
                   V);
+    if (auto AA = Attrs.getFnAttr("sign-return-address"); !AA.isValid()) {
+      CheckFailed(
+          "'sign-return-address-key' present without `sign-return-address`");
+    }
   }
 
   if (auto A = Attrs.getFnAttr("branch-target-enforcement"); A.isValid()) {
     StringRef S = A.getValueAsString();
-    if (S != "true" && S != "false")
+    if (S != "" && S != "true" && S != "false")
       CheckFailed(
           "invalid value for 'branch-target-enforcement' attribute: " + S, V);
   }
 
+  if (auto A = Attrs.getFnAttr("branch-protection-pauth-lr"); A.isValid()) {
+    StringRef S = A.getValueAsString();
+    if (S != "" && S != "true" && S != "false")
+      CheckFailed(
+          "invalid value for 'branch-protection-pauth-lr' attribute: " + S, V);
+  }
+
+  if (auto A = Attrs.getFnAttr("guarded-control-stack"); A.isValid()) {
+    StringRef S = A.getValueAsString();
+    if (S != "" && S != "true" && S != "false")
+      CheckFailed("invalid value for 'guarded-control-stack' attribute: " + S,
+                  V);
+  }
+
   if (auto A = Attrs.getFnAttr("vector-function-abi-variant"); A.isValid()) {
     StringRef S = A.getValueAsString();
     const std::optional<VFInfo> Info = VFABI::tryDemangleForVFABI(S, FT);

diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -272,17 +272,17 @@ void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
   unsigned Flags = 0;
   if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
           M.getModuleFlag("branch-target-enforcement")))
-    if (BTE->getZExtValue())
+    if (!BTE->isZero())
       Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
 
   if (const auto *GCS = mdconst::extract_or_null<ConstantInt>(
           M.getModuleFlag("guarded-control-stack")))
-    if (GCS->getZExtValue())
+    if (!GCS->isZero())
       Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_GCS;
 
   if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
           M.getModuleFlag("sign-return-address")))
-    if (Sign->getZExtValue())
+    if (!Sign->isZero())
       Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
 
   uint64_t PAuthABIPlatform = -1;