Software Bill of Mitigations Tests

- Add tests for verifying metadata added correctly
- Added new parameter to only add mitigation metadata for functions when MitigationAnalysis CGO is enabled

Author: matthewlevy97

clang/lib/CodeGen/CodeGenModule.cpp

@@ -2492,7 +2492,8 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
     B.addUWTableAttr(llvm::UWTableKind(CodeGenOpts.UnwindTables));
 
   AttachMitigationMetadataToFunction(*F, MitigationKey::STACK_CLASH_PROTECTION,
-                                     CodeGenOpts.StackClashProtector);
+                                     CodeGenOpts.StackClashProtector,
+                                     CodeGenOpts.MitigationAnalysis);
   if (CodeGenOpts.StackClashProtector)
     B.addAttribute("probe-stack", "inline-asm");
 
@@ -2521,18 +2522,21 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
       !noStackProtectionAttr &&
           (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPOn) ||
            isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPStrong) ||
-           isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq)));
+           isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq)),
+      CodeGenOpts.MitigationAnalysis);
 
   AttachMitigationMetadataToFunction(
       *F, MitigationKey::STACK_PROTECTOR_STRONG,
       !noStackProtectionAttr &&
           (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPStrong) ||
-           isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq)));
+           isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq)),
+      CodeGenOpts.MitigationAnalysis);
 
   AttachMitigationMetadataToFunction(
       *F, MitigationKey::STACK_PROTECTOR_ALL,
       !noStackProtectionAttr &&
-          isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq));
+          isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq),
+      CodeGenOpts.MitigationAnalysis);
 
   if (!D) {
     // Non-entry HLSL functions must always be inlined.

clang/lib/CodeGen/MitigationTagging.cpp

@@ -44,8 +44,17 @@ MitigationKeyToString(enum MitigationKey key) noexcept {
   }
 }
 
+///
+/// Store metadata (tied to the function) related to enablement of mitigations.
+/// @param mitigationAnalysisEnable - if false, do not attach metadata.
+///
 void AttachMitigationMetadataToFunction(llvm::Function &F,
-                                        enum MitigationKey key, bool enabled) {
+                                        enum MitigationKey key, bool enabled,
+                                        bool mitigationAnalysisEnable) {
+  if (!mitigationAnalysisEnable) {
+    return;
+  }
+
   llvm::LLVMContext &Context = F.getContext();
 
   unsigned kindID = Context.getMDKindID("security_mitigations");
@@ -68,16 +77,15 @@ void AttachMitigationMetadataToFunction(llvm::Function &F,
     llvm::MDNode *CombinedMD = llvm::MDNode::get(Context, MDs);
     F.setMetadata(kindID, CombinedMD);
   } else {
-    F.setMetadata(kindID, NewMD);
+    F.setMetadata(kindID, llvm::MDNode::get(
+                              Context, std::vector<llvm::Metadata *>{NewMD}));
   }
 }
 
 void AttachMitigationMetadataToFunction(CodeGenFunction &CGF,
                                         enum MitigationKey key, bool enabled) {
-  if (!CGF.CGM.getCodeGenOpts().MitigationAnalysis) {
-    return;
-  }
-  AttachMitigationMetadataToFunction(*(CGF.CurFn), key, enabled);
+  AttachMitigationMetadataToFunction(
+      *(CGF.CurFn), key, enabled, CGF.CGM.getCodeGenOpts().MitigationAnalysis);
 }
 
 } // namespace CodeGen

clang/lib/CodeGen/MitigationTagging.h

@@ -35,7 +35,8 @@ enum class MitigationKey {
 };
 
 void AttachMitigationMetadataToFunction(llvm::Function &F,
-                                        enum MitigationKey key, bool enabled);
+                                        enum MitigationKey key, bool enabled,
+                                        bool mitigationAnalysisEnable);
 void AttachMitigationMetadataToFunction(CodeGenFunction &CGF,
                                         enum MitigationKey key, bool enabled);
 

clang/unittests/CodeGen/CMakeLists.txt

@@ -9,6 +9,7 @@ add_clang_unittest(ClangCodeGenTests
   CodeGenExternalTest.cpp
   TBAAMetadataTest.cpp
   CheckTargetFeaturesTest.cpp
+  MitigationAnalysisTest.cpp
   )
 
 clang_target_link_libraries(ClangCodeGenTests