[PATCH] D130065: [X86] Use Min behavior for cf-protection-{return,branch}/ibt-seal module flags

[Fangrui Song via Phabricator via cfe-commits]

MaskRay created this revision.
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These features require that all object files are compiled with the support. When
the feature is disabled for an object file, the merge behavior should treat the
file having a value of 0 (see D129911 <https://reviews.llvm.org/D129911>).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D130065

Files:
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/test/CodeGen/X86/x86-cf-protection.c


Index: clang/test/CodeGen/X86/x86-cf-protection.c
===================================================================
--- clang/test/CodeGen/X86/x86-cf-protection.c
+++ clang/test/CodeGen/X86/x86-cf-protection.c
@@ -8,7 +8,7 @@
 // RETURN: #define __CET__ 2
 // BRANCH: #define __CET__ 1
 // FULL: #define __CET__ 3
-// CFPROT: "cf-protection-branch", i32 1
-// IBTSEAL: "ibt-seal", i32 1
+// CFPROT: !{i32 8, !"cf-protection-branch", i32 1}
+// IBTSEAL: !{i32 8, !"ibt-seal", i32 1}
 // NOIBTSEAL-NOT: "ibt-seal", i32 1
 void foo() {}
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -743,19 +743,19 @@
   if (CodeGenOpts.CFProtectionReturn &&
       Target.checkCFProtectionReturnSupported(getDiags())) {
     // Indicate that we want to instrument return control flow protection.
-    getModule().addModuleFlag(llvm::Module::Override, "cf-protection-return",
+    getModule().addModuleFlag(llvm::Module::Min, "cf-protection-return",
                               1);
   }
 
   if (CodeGenOpts.CFProtectionBranch &&
       Target.checkCFProtectionBranchSupported(getDiags())) {
     // Indicate that we want to instrument branch control flow protection.
-    getModule().addModuleFlag(llvm::Module::Override, "cf-protection-branch",
+    getModule().addModuleFlag(llvm::Module::Min, "cf-protection-branch",
                               1);
   }
 
   if (CodeGenOpts.IBTSeal)
-    getModule().addModuleFlag(llvm::Module::Override, "ibt-seal", 1);
+    getModule().addModuleFlag(llvm::Module::Min, "ibt-seal", 1);
 
   if (CodeGenOpts.FunctionReturnThunks)
     getModule().addModuleFlag(llvm::Module::Override, "function_return_thunk_extern", 1);


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