[clang][slh] add Clang attr no_speculative_load_hardening

Summary:
This attribute will allow users to opt specific functions out of
speculative load hardening. This compliments the Clang attribute
named speculative_load_hardening. When this attribute or the attribute
speculative_load_hardening is used in combination with the flags
-mno-speculative-load-hardening or -mspeculative-load-hardening,
the function level attribute will override the default during LLVM IR
generation. For example, in the case, where the flag opposes the
function attribute, the function attribute will take precendence.
The sticky inlining behavior of the speculative_load_hardening attribute
may cause a function with the no_speculative_load_hardening attribute
to be tagged with the speculative_load_hardening tag in
subsequent compiler phases which is desired behavior since the
speculative_load_hardening LLVM attribute is designed to be maximally
conservative.

If both attributes are specified for a function, then an error will be
thrown.

Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54909

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@351565 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index 1fe1dd39948a1b68b47bc99fd56bb5ded34864e4..42f4d2f6d29eea67072e23acfdebe8c47660ed33 100644 (file)
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -3149,6 +3149,12 @@ def SpeculativeLoadHardening : InheritableAttr {
   let Documentation = [SpeculativeLoadHardeningDocs];
 }
 
+def NoSpeculativeLoadHardening : InheritableAttr {
+  let Spellings = [Clang<"no_speculative_load_hardening">];
+  let Subjects = SubjectList<[Function, ObjCMethod], ErrorDiag>;
+  let Documentation = [NoSpeculativeLoadHardeningDocs];
+}
+
 def Uninitialized : InheritableAttr {
   let Spellings = [Clang<"uninitialized", 0>];
   let Subjects = SubjectList<[LocalVar]>;

diff --git a/include/clang/Basic/AttrDocs.td b/include/clang/Basic/AttrDocs.td
index 5773a92c9c15dd8084cdd76495eca751e3b57b87..eec62136764ea1c238f8fbce223e7ba5fe41e58b 100644 (file)
--- a/include/clang/Basic/AttrDocs.td
+++ b/include/clang/Basic/AttrDocs.td
@@ -3822,7 +3822,8 @@ def SpeculativeLoadHardeningDocs : Documentation {
   This attribute can be applied to a function declaration in order to indicate
   that `Speculative Load Hardening <https://llvm.org/docs/SpeculativeLoadHardening.html>`_
   should be enabled for the function body. This can also be applied to a method
-  in Objective C.
+  in Objective C. This attribute will take precedence over the command line flag in
+  the case where `-mno-speculative-load-hardening <https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-mspeculative-load-hardening>`_ is specified.
 
   Speculative Load Hardening is a best-effort mitigation against
   information leak attacks that make use of control flow
@@ -3840,6 +3841,42 @@ def SpeculativeLoadHardeningDocs : Documentation {
   }];
 }
 
+def NoSpeculativeLoadHardeningDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+  This attribute can be applied to a function declaration in order to indicate
+  that `Speculative Load Hardening <https://llvm.org/docs/SpeculativeLoadHardening.html>`_
+  is *not* needed for the function body. This can also be applied to a method
+  in Objective C. This attribute will take precedence over the command line flag in
+  the case where `-mspeculative-load-hardening <https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-mspeculative-load-hardening>`_ is specified.
+
+  Warning: This attribute may not prevent Speculative Load Hardening from being
+  enabled for a function which inlines a function that has the
+  'speculative_load_hardening' attribute. This is intended to provide a
+  maximally conservative model where the code that is marked with the
+  'speculative_load_hardening' attribute will always (even when inlined)
+  be hardened. A user of this attribute may want to mark functions called by
+  a function they do not want to be hardened with the 'noinline' attribute.
+
+  For example:
+
+  .. code-block:: c
+
+    __attribute__((speculative_load_hardening))
+    int foo(int i) {
+      return i;
+    }
+
+    // Note: bar() may still have speculative load hardening enabled if
+    // foo() is inlined into bar(). Mark foo() with __attribute__((noinline))
+    // to avoid this situation.
+    __attribute__((no_speculative_load_hardening))
+    int bar(int i) {
+      return foo(i);
+    }
+  }];
+}
+
 def ObjCExternallyRetainedDocs : Documentation {
   let Category = DocCatVariable;
   let Content = [{

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index e5b7465820a9827f906b58ff0773e0bc7ae70ff3..e6279d8209f70276e2fd482ef241e3ea6defb484 100644 (file)
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -2496,6 +2496,12 @@ public:
                                           unsigned AttrSpellingListIndex);
   MinSizeAttr *mergeMinSizeAttr(Decl *D, SourceRange Range,
                                 unsigned AttrSpellingListIndex);
+  NoSpeculativeLoadHardeningAttr *
+  mergeNoSpeculativeLoadHardeningAttr(Decl *D,
+                                      const NoSpeculativeLoadHardeningAttr &AL);
+  SpeculativeLoadHardeningAttr *
+  mergeSpeculativeLoadHardeningAttr(Decl *D,
+                                    const SpeculativeLoadHardeningAttr &AL);
   OptimizeNoneAttr *mergeOptimizeNoneAttr(Decl *D, SourceRange Range,
                                           unsigned AttrSpellingListIndex);
   InternalLinkageAttr *mergeInternalLinkageAttr(Decl *D, const ParsedAttr &AL);

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 7d494bb1f1c76b003a3ff87a3c6e1b563524683c..7f43157b4dc35bef09af155aa0484a668b680bd2 100644 (file)
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -1793,8 +1793,6 @@ void CodeGenModule::ConstructDefaultFnAttrList(StringRef Name, bool HasOptnone,
     if (CodeGenOpts.Backchain)
       FuncAttrs.addAttribute("backchain");
 
-    // FIXME: The interaction of this attribute with the SLH command line flag
-    // has not been determined.
     if (CodeGenOpts.SpeculativeLoadHardening)
       FuncAttrs.addAttribute(llvm::Attribute::SpeculativeLoadHardening);
   }
@@ -1864,8 +1862,6 @@ void CodeGenModule::ConstructAttributeList(
       FuncAttrs.addAttribute(llvm::Attribute::NoDuplicate);
     if (TargetDecl->hasAttr<ConvergentAttr>())
       FuncAttrs.addAttribute(llvm::Attribute::Convergent);
-    if (TargetDecl->hasAttr<SpeculativeLoadHardeningAttr>())
-      FuncAttrs.addAttribute(llvm::Attribute::SpeculativeLoadHardening);
 
     if (const FunctionDecl *Fn = dyn_cast<FunctionDecl>(TargetDecl)) {
       AddAttributesFromFunctionProtoType(
@@ -1910,6 +1906,16 @@ void CodeGenModule::ConstructAttributeList(
 
   ConstructDefaultFnAttrList(Name, HasOptnone, AttrOnCallSite, FuncAttrs);
 
+  // This must run after constructing the default function attribute list
+  // to ensure that the speculative load hardening attribute is removed
+  // in the case where the -mspeculative-load-hardening flag was passed.
+  if (TargetDecl) {
+    if (TargetDecl->hasAttr<NoSpeculativeLoadHardeningAttr>())
+      FuncAttrs.removeAttribute(llvm::Attribute::SpeculativeLoadHardening);
+    if (TargetDecl->hasAttr<SpeculativeLoadHardeningAttr>())
+      FuncAttrs.addAttribute(llvm::Attribute::SpeculativeLoadHardening);
+  }
+
   if (CodeGenOpts.EnableSegmentedStacks &&
       !(TargetDecl && TargetDecl->hasAttr<NoSplitStackAttr>()))
     FuncAttrs.addAttribute("split-stack");

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 23c99d45a78d4d1b8f13890e617968ba59c57d43..03061eab35903eb3c3dec04ab03fb5bd977a6427 100644 (file)
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2489,6 +2489,10 @@ static bool mergeDeclAttribute(Sema &S, NamedDecl *D,
   else if (const auto *UA = dyn_cast<UuidAttr>(Attr))
     NewAttr = S.mergeUuidAttr(D, UA->getRange(), AttrSpellingListIndex,
                               UA->getGuid());
+  else if (const auto *SLHA = dyn_cast<SpeculativeLoadHardeningAttr>(Attr))
+    NewAttr = S.mergeSpeculativeLoadHardeningAttr(D, *SLHA);
+  else if (const auto *SLHA = dyn_cast<NoSpeculativeLoadHardeningAttr>(Attr))
+    NewAttr = S.mergeNoSpeculativeLoadHardeningAttr(D, *SLHA);
   else if (Attr->shouldInheritEvenIfAlreadyPresent() || !DeclHasAttr(D, Attr))
     NewAttr = cast<InheritableAttr>(Attr->clone(S.Context));
 

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 139ac8aab4333c9c5c3b261e700293d3ea0118f4..7cfdb9e286b909761a4c37085c4176545f7f96e4 100644 (file)
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -4157,6 +4157,15 @@ MinSizeAttr *Sema::mergeMinSizeAttr(Decl *D, SourceRange Range,
   return ::new (Context) MinSizeAttr(Range, Context, AttrSpellingListIndex);
 }
 
+NoSpeculativeLoadHardeningAttr *Sema::mergeNoSpeculativeLoadHardeningAttr(
+    Decl *D, const NoSpeculativeLoadHardeningAttr &AL) {
+  if (checkAttrMutualExclusion<SpeculativeLoadHardeningAttr>(*this, D, AL))
+    return nullptr;
+
+  return ::new (Context) NoSpeculativeLoadHardeningAttr(
+      AL.getRange(), Context, AL.getSpellingListIndex());
+}
+
 OptimizeNoneAttr *Sema::mergeOptimizeNoneAttr(Decl *D, SourceRange Range,
                                               unsigned AttrSpellingListIndex) {
   if (AlwaysInlineAttr *Inline = D->getAttr<AlwaysInlineAttr>()) {
@@ -4177,6 +4186,15 @@ OptimizeNoneAttr *Sema::mergeOptimizeNoneAttr(Decl *D, SourceRange Range,
                                           AttrSpellingListIndex);
 }
 
+SpeculativeLoadHardeningAttr *Sema::mergeSpeculativeLoadHardeningAttr(
+    Decl *D, const SpeculativeLoadHardeningAttr &AL) {
+  if (checkAttrMutualExclusion<NoSpeculativeLoadHardeningAttr>(*this, D, AL))
+    return nullptr;
+
+  return ::new (Context) SpeculativeLoadHardeningAttr(
+      AL.getRange(), Context, AL.getSpellingListIndex());
+}
+
 static void handleAlwaysInlineAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   if (checkAttrMutualExclusion<NotTailCalledAttr>(S, D, AL))
     return;
@@ -6618,7 +6636,13 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
     handleSectionAttr(S, D, AL);
     break;
   case ParsedAttr::AT_SpeculativeLoadHardening:
-    handleSimpleAttribute<SpeculativeLoadHardeningAttr>(S, D, AL);
+    handleSimpleAttributeWithExclusions<SpeculativeLoadHardeningAttr,
+                                        NoSpeculativeLoadHardeningAttr>(S, D,
+                                                                        AL);
+    break;
+  case ParsedAttr::AT_NoSpeculativeLoadHardening:
+    handleSimpleAttributeWithExclusions<NoSpeculativeLoadHardeningAttr,
+                                        SpeculativeLoadHardeningAttr>(S, D, AL);
     break;
   case ParsedAttr::AT_CodeSeg:
     handleCodeSegAttr(S, D, AL);

diff --git a/test/CodeGen/attr-speculative-load-hardening.cpp b/test/CodeGen/attr-speculative-load-hardening.cpp
deleted file mode 100644 (file)
index e2eb805..0000000
--- a/test/CodeGen/attr-speculative-load-hardening.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-// RUN: %clang_cc1 -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK1
-// RUN: %clang_cc1 -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK2
-//
-// Check that we set the attribute on each function.
-
-[[clang::speculative_load_hardening]]
-int test1() {
-  return 42;
-}
-
-int __attribute__((speculative_load_hardening)) test2() {
-  return 42;
-}
-// CHECK1: @{{.*}}test1{{.*}}[[SLH1:#[0-9]+]]
-// CHECK1: attributes [[SLH1]] = { {{.*}}speculative_load_hardening{{.*}} }
-
-// CHECK2: @{{.*}}test2{{.*}}[[SLH2:#[0-9]+]]
-// CHECK2: attributes [[SLH2]] = { {{.*}}speculative_load_hardening{{.*}} }

diff --git a/test/CodeGenCXX/attr-speculative-load-hardening.cpp b/test/CodeGenCXX/attr-speculative-load-hardening.cpp
new file mode 100644 (file)
index 0000000..22c5dd5
--- /dev/null
+++ b/test/CodeGenCXX/attr-speculative-load-hardening.cpp
@@ -0,0 +1,62 @@
+// Check that we correctly set or did not set the attribute for each function.
+// RUN: %clang_cc1 -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK1
+// RUN: %clang_cc1 -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK2
+
+// Check that we correctly set or did not set the attribute on each function despite the
+// -mspeculative-load-hardening flag.
+// RUN: %clang_cc1 -mspeculative-load-hardening -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK3
+// RUN: %clang_cc1 -mspeculative-load-hardening -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK4
+
+
+// Check that we correctly set or did not set the attribute on each function despite the
+// -mno-speculative-load-hardening flag.
+// RUN: %clang -mno-speculative-load-hardening -S -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK5
+// RUN: %clang -mno-speculative-load-hardening -S -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK6
+
+
+[[clang::speculative_load_hardening]]
+int test1() {
+  return 42;
+}
+
+int __attribute__((speculative_load_hardening)) test2() {
+  return 42;
+}
+
+[[clang::no_speculative_load_hardening]]
+int test3() {
+  return 42;
+}
+
+int __attribute__((no_speculative_load_hardening)) test4() {
+  return 42;
+}
+// CHECK1: @{{.*}}test1{{.*}}[[SLH:#[0-9]+]]
+// CHECK1: @{{.*}}test3{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK1: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK1-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK2: @{{.*}}test2{{.*}}[[SLH:#[0-9]+]]
+// CHECK2: @{{.*}}test4{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK2: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK2-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK3: @{{.*}}test1{{.*}}[[SLH:#[0-9]+]]
+// CHECK3: @{{.*}}test3{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK3: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK3-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK4: @{{.*}}test2{{.*}}[[SLH:#[0-9]+]]
+// CHECK4: @{{.*}}test4{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK4: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK4-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK5: @{{.*}}test1{{.*}}[[SLH:#[0-9]+]]
+// CHECK5: @{{.*}}test3{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK5: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK5-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK6: @{{.*}}test2{{.*}}[[SLH:#[0-9]+]]
+// CHECK6: @{{.*}}test4{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK6: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK6-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }

diff --git a/test/CodeGen/attr-speculative-load-hardening.m b/test/CodeGenObjC/attr-speculative-load-hardening.m
similarity index 56%
rename from test/CodeGen/attr-speculative-load-hardening.m
rename to test/CodeGenObjC/attr-speculative-load-hardening.m
index 2de945b974fafcb9af79e777c8ed13d4f73b1a7b..3b4929d9356815982ae5c79a48d790e380fe438b 100644 (file)
--- a/test/CodeGen/attr-speculative-load-hardening.m
+++ b/test/CodeGenObjC/attr-speculative-load-hardening.m
@@ -4,6 +4,11 @@ int main() __attribute__((speculative_load_hardening)) {
   return 0;
 }
 
-// SLH: @{{.*}}main{{.*}}[[SLH:#[0-9]+]]
+int test() __attribute__((no_speculative_load_hardening)) {
+  return 0;
+}
 
+// SLH: @{{.*}}main{{.*}}[[SLH:#[0-9]+]]
+// SLH: @{{.*}}test{{.*}}[[NOSLH:#[0-9]+]]
 // SLH: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// SLH-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }

diff --git a/test/Misc/pragma-attribute-supported-attributes-list.test b/test/Misc/pragma-attribute-supported-attributes-list.test
index 9a6bcca1bd36bf6903c27d805ef5cc287ffd65eb..9dec259f4fc097cc51253a59fc88bd3a52c179e4 100644 (file)
--- a/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -80,6 +80,7 @@
 // CHECK-NEXT: NoMips16 (SubjectMatchRule_function)
 // CHECK-NEXT: NoSanitize (SubjectMatchRule_function, SubjectMatchRule_objc_method, SubjectMatchRule_variable_is_global)
 // CHECK-NEXT: NoSanitizeSpecific (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
+// CHECK-NEXT: NoSpeculativeLoadHardening (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: NoSplitStack (SubjectMatchRule_function)
 // CHECK-NEXT: NoStackProtector (SubjectMatchRule_function)
 // CHECK-NEXT: NoThreadSafetyAnalysis (SubjectMatchRule_function)

diff --git a/test/SemaCXX/attr-no-speculative-load-hardening.cpp b/test/SemaCXX/attr-no-speculative-load-hardening.cpp
new file mode 100644 (file)
index 0000000..eebc527
--- /dev/null
+++ b/test/SemaCXX/attr-no-speculative-load-hardening.cpp
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
+
+int i __attribute__((no_speculative_load_hardening)); // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+void f1() __attribute__((no_speculative_load_hardening));
+void f2() __attribute__((no_speculative_load_hardening(1))); // expected-error {{'no_speculative_load_hardening' attribute takes no arguments}}
+
+template <typename T>
+void tf1() __attribute__((no_speculative_load_hardening));
+
+int f3(int __attribute__((no_speculative_load_hardening)), int); // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+struct A {
+  int f __attribute__((no_speculative_load_hardening));  // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+  void mf1() __attribute__((no_speculative_load_hardening));
+  static void mf2() __attribute__((no_speculative_load_hardening));
+};
+
+int ci [[clang::no_speculative_load_hardening]]; // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+[[clang::no_speculative_load_hardening]] void cf1();
+[[clang::no_speculative_load_hardening(1)]] void cf2(); // expected-error {{'no_speculative_load_hardening' attribute takes no arguments}}
+
+template <typename T>
+[[clang::no_speculative_load_hardening]]
+void ctf1();
+
+int cf3(int c[[clang::no_speculative_load_hardening]], int); // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+struct CA {
+  int f [[clang::no_speculative_load_hardening]];  // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+  [[clang::no_speculative_load_hardening]] void mf1();
+  [[clang::no_speculative_load_hardening]] static void mf2();
+};

diff --git a/test/SemaCXX/attr-speculative-load-hardening.cpp b/test/SemaCXX/attr-speculative-load-hardening.cpp
index bba3b6921e8d84fced4b80a27bc4fed7fe64ba49..ff31e4be1799e050cae97e59bf74b1f61d8e15ac 100644 (file)
--- a/test/SemaCXX/attr-speculative-load-hardening.cpp
+++ b/test/SemaCXX/attr-speculative-load-hardening.cpp
@@ -16,6 +16,17 @@ struct A {
   static void mf2() __attribute__((speculative_load_hardening));
 };
 
+void f4() __attribute__((no_speculative_load_hardening, speculative_load_hardening)); // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+void f5() __attribute__((speculative_load_hardening, no_speculative_load_hardening)); // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+void f6() __attribute__((no_speculative_load_hardening));
+
+void f6() __attribute__((speculative_load_hardening)); // expected-error@-2 {{'no_speculative_load_hardening' and 'speculative_load_hardening' attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
 int ci [[clang::speculative_load_hardening]]; // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
 
 [[clang::speculative_load_hardening]] void cf1();
@@ -32,3 +43,16 @@ struct CA {
   [[clang::speculative_load_hardening]] void mf1();
   [[clang::speculative_load_hardening]] static void mf2();
 };
+
+[[clang::speculative_load_hardening, clang::no_speculative_load_hardening]] void cf4();  // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+[[clang::no_speculative_load_hardening, clang::speculative_load_hardening]] void cf5();  // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+[[clang::speculative_load_hardening]]
+void cf6();
+
+[[clang::no_speculative_load_hardening]]
+void cf6(); // expected-error@-4 {{'speculative_load_hardening' and 'no_speculative_load_hardening' attributes are not compatible}} \
+// expected-note@-1 {{conflicting attribute is here}}