[clang] 23ba688 - [X86] Use Min behavior for cf-protection-{return,branch}/ibt-seal module flags

[Fangrui Song via cfe-commits]

Author: Fangrui Song
Date: 2022-07-19T21:20:02-07:00
New Revision: 23ba688f02ea72b0af3480cd95d31e9a79f2d92a

URL: https://github.com/llvm/llvm-project/commit/23ba688f02ea72b0af3480cd95d31e9a79f2d92a
DIFF: https://github.com/llvm/llvm-project/commit/23ba688f02ea72b0af3480cd95d31e9a79f2d92a.diff

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

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).

Reviewed By: xiangzhangllvm

Differential Revision: https://reviews.llvm.org/D130065

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 4daf4120e0cae..2ec71fa297659 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -743,19 +743,19 @@ void CodeGenModule::Release() {
   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);

diff  --git a/clang/test/CodeGen/X86/x86-cf-protection.c b/clang/test/CodeGen/X86/x86-cf-protection.c
index 815ef3f8479e2..de6906ec51812 100644
--- a/clang/test/CodeGen/X86/x86-cf-protection.c
+++ b/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() {}