[Clang] Emit KCFI type hashes for member functions

With `-fsanitize=kcfi`, Clang currently won't emit type hashes for
C++ member functions, which leads to check failures if they are
indirectly called. As there's no reason to exclude member functions
in CodeGenModule::setKCFIType, emit type hashes also for them to fix
member function pointer calls with KCFI, and add a test to confirm
that types are emitted correctly.

Author: samitolvanen

clang/lib/CodeGen/CodeGenModule.cpp

@@ -2610,9 +2610,6 @@ void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
 }
 
 void CodeGenModule::setKCFIType(const FunctionDecl *FD, llvm::Function *F) {
-  if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
-    return;
-
   llvm::LLVMContext &Ctx = F->getContext();
   llvm::MDBuilder MDB(Ctx);
   F->setMetadata(llvm::LLVMContext::MD_kcfi_type,

clang/test/CodeGen/kcfi.c

@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -o - %s | FileCheck %s
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -x c++ -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -x c++ -o - %s | FileCheck %s --check-prefixes=CHECK,MEMBER
 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -fpatchable-function-entry-offset=3 -o - %s | FileCheck %s --check-prefixes=CHECK,OFFSET
 #if !__has_feature(kcfi)
 #error Missing kcfi?
@@ -54,7 +54,21 @@ int test(void) {
          f6();
 }
 
+#ifdef __cplusplus
+struct A {
+  // MEMBER-DAG: define{{.*}} void @_ZN1A1fEv(ptr{{.*}} %this){{.*}} !kcfi_type ![[#TYPE3:]]
+  void f() {}
+};
+
+void test_member_call(void) {
+  void (A::* p)() = &A::f;
+  // MEMBER-DAG: call void %[[#]](ptr{{.*}} [ "kcfi"(i32 [[#%d,HASH3:]]) ]
+  (A().*p)();
+}
+#endif
+
 // CHECK-DAG: ![[#]] = !{i32 4, !"kcfi", i32 1}
 // OFFSET-DAG: ![[#]] = !{i32 4, !"kcfi-offset", i32 3}
 // CHECK-DAG: ![[#TYPE]] = !{i32 [[#HASH]]}
 // CHECK-DAG: ![[#TYPE2]] = !{i32 [[#%d,HASH2:]]}
+// MEMBER-DAG: ![[#TYPE3]] = !{i32 [[#HASH3]]}