[WIP][PAC] Emit IR debug info metadata nodes for implicitly signed pointers

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -1058,8 +1058,25 @@ llvm::DIType *CGDebugInfo::CreateType(const ObjCObjectPointerType *Ty,
 
 llvm::DIType *CGDebugInfo::CreateType(const PointerType *Ty,
                                       llvm::DIFile *Unit) {
-  return CreatePointerLikeType(llvm::dwarf::DW_TAG_pointer_type, Ty,
-                               Ty->getPointeeType(), Unit);
+  llvm::DIType *DIPointerTy = CreatePointerLikeType(
+      llvm::dwarf::DW_TAG_pointer_type, Ty, Ty->getPointeeType(), Unit);
+
+  if (!Ty->getPointeeType()->isFunctionType())
+    return DIPointerTy;
+
+  CGPointerAuthInfo SignSchema =
+      CGM.getFunctionPointerAuthInfo(QualType(Ty, 0));
+  if (!SignSchema)
+    return DIPointerTy;
+
+  llvm::ConstantInt *Discr =
+      cast_or_null<llvm::ConstantInt>(SignSchema.getDiscriminator());
+  // See CodeGenModule::getMemberFunctionPointer in CGPointerAuth.cpp - we
+  // do not use address discrimination
+  return DBuilder.createPtrAuthQualifiedType(
+      DIPointerTy, SignSchema.getKey(), false,
+      Discr ? Discr->getValue().getZExtValue() : 0, SignSchema.isIsaPointer(),
+      SignSchema.authenticatesNullValues());
 }
 
 /// \return whether a C++ mangling exists for the type defined by TD.
@@ -2432,6 +2449,14 @@ void CGDebugInfo::CollectVTableInfo(const CXXRecordDecl *RD, llvm::DIFile *Unit,
   if (!VPtrTy)
     VPtrTy = getOrCreateVTablePtrType(Unit);
 
+  if (std::optional<PointerAuthQualifier> VTAuth =
+          CGM.getVTablePointerAuthentication(RD)) {
+    VPtrTy = DBuilder.createPtrAuthQualifiedType(
+        VPtrTy, VTAuth->getKey(), VTAuth->isAddressDiscriminated(),
+        VTAuth->getExtraDiscriminator(), VTAuth->isIsaPointer(),
+        VTAuth->authenticatesNullValues());
+  }
+
   unsigned Size = CGM.getContext().getTypeSize(CGM.getContext().VoidPtrTy);
   llvm::DIType *VPtrMember =
       DBuilder.createMemberType(Unit, getVTableName(RD), Unit, 0, Size, 0, 0,
@@ -3311,11 +3336,26 @@ llvm::DIType *CGDebugInfo::CreateType(const MemberPointerType *Ty,
 
   const FunctionProtoType *FPT =
       Ty->getPointeeType()->castAs<FunctionProtoType>();
-  return DBuilder.createMemberPointerType(
+
+  llvm::DIType *DIPointerTy = DBuilder.createMemberPointerType(
       getOrCreateInstanceMethodType(
           CXXMethodDecl::getThisType(FPT, Ty->getMostRecentCXXRecordDecl()),
           FPT, U),
       ClassType, Size, /*Align=*/0, Flags);
+
+  CGPointerAuthInfo SignSchema =
+      CGM.getMemberFunctionPointerAuthInfo(QualType(Ty, 0));
+  if (!SignSchema)
+    return DIPointerTy;
+
+  llvm::ConstantInt *Discr =
+      cast_or_null<llvm::ConstantInt>(SignSchema.getDiscriminator());
+  // See CodeGenModule::getFunctionPointer in CGPointerAuth.cpp - we do not
+  // use address discrimination
+  return DBuilder.createPtrAuthQualifiedType(
+      DIPointerTy, SignSchema.getKey(), false,
+      Discr ? Discr->getValue().getZExtValue() : 0, SignSchema.isIsaPointer(),
+      SignSchema.authenticatesNullValues());
 }
 
 llvm::DIType *CGDebugInfo::CreateType(const AtomicType *Ty, llvm::DIFile *U) {

clang/test/CodeGen/ptrauth-debuginfo-implicit.cpp

@@ -0,0 +1,104 @@
+// RUN: split-file %s %t && cd %t
+
+//--- vtptr.cpp
+
+// RUN: %clang -g -target aarch64-elf -mbranch-protection=pauthabi \
+// RUN:   -S -emit-llvm vtptr.cpp -o - | FileCheck vtptr.cpp
+
+// CHECK:      !DIDerivedType(tag: DW_TAG_member
+// CHECK-SAME: name: "_vptr$A"
+// CHECK-SAME: baseType: [[BASE1:![0-9]+]]
+
+// CHECK:      [[BASE1]] = !DIDerivedType(tag: DW_TAG_LLVM_ptrauth_type
+// CHECK-SAME: baseType: [[BASE2:![0-9]+]]
+// CHECK-SAME: ptrAuthKey: 2
+// CHECK-SAME: ptrAuthIsAddressDiscriminated: true
+// CHECK-SAME: ptrAuthExtraDiscriminator: 62866
+// CHECK-SAME: ptrAuthIsaPointer: false
+// CHECK-SAME: ptrAuthAuthenticatesNullValues: false
+
+// CHECK:      [[BASE2]] = !DIDerivedType(tag: DW_TAG_pointer_type
+// CHECK-SAME: baseType: [[BASE3:![0-9]+]]
+
+// CHECK:      [[BASE3]] = !DIDerivedType(tag: DW_TAG_pointer_type
+// CHECK-SAME: name: "__vtbl_ptr_type"
+// CHECK-SAME: baseType: [[BASE4:![0-9]+]]
+
+// CHECK:      [[BASE4]] = !DISubroutineType
+
+struct A {
+  virtual void foo() {};
+};
+
+void bar(A& a) {
+  a.foo();
+}
+
+void test() {
+  A a;
+  bar(a);
+}
+
+//--- fptr.c
+
+// RUN: %clang -g -target aarch64-elf -mbranch-protection=pauthabi \
+// RUN:   -S -emit-llvm fptr.c -o - | FileCheck fptr.c
+
+// CHECK:      !DIGlobalVariable(name: "y"
+// CHECK-SAME: type: [[TYPE:![0-9]+]]
+
+/* IA key and zero extra discriminator are not emitted in IR metadata nodes
+ * but are still present in Dwarf output generated. */
+
+// CHECK:      [[TYPE]] = !DIDerivedType(tag: DW_TAG_LLVM_ptrauth_type
+// CHECK-SAME: baseType: [[BASE1:![0-9]+]]
+// CHECK-SAME: ptrAuthIsAddressDiscriminated: false
+// CHECK-SAME: ptrAuthIsaPointer: false
+// CHECK-SAME: ptrAuthAuthenticatesNullValues: false
+
+// CHECK:      [[BASE1]] = !DIDerivedType(tag: DW_TAG_pointer_type
+// CHECK-SAME: baseType: [[BASE2:![0-9]+]]
+
+// CHECK:      [[BASE2]] = !DIDerivedType(tag: DW_TAG_typedef
+// CHECK-SAME: name: "fptr"
+
+typedef void fptr();
+
+fptr x;
+
+fptr *y = &x;
+
+//--- member-fptr.cpp
+
+// RUN: %clang -g -target aarch64-elf -mbranch-protection=pauthabi \
+// RUN:   -S -emit-llvm member-fptr.cpp -o - | FileCheck member-fptr.cpp
+
+// CHECK:      !DIGlobalVariable(name: "x"
+// CHECK-SAME: type: [[TYPEDEF:![0-9]+]]
+
+// CHECK:      [[TYPEDEF]] = !DIDerivedType(tag: DW_TAG_typedef
+// CHECK-SAME: name: "fptr",
+// CHECK-SAME: baseType: [[TYPE:![0-9]+]]
+
+/* IA key is not emitted in IR metadata nodes but is still present
+ * in Dwarf output generated. */
+
+// CHECK:      [[TYPE]] = !DIDerivedType(tag: DW_TAG_LLVM_ptrauth_type
+// CHECK-SAME: baseType: [[BASE1:![0-9]+]]
+// CHECK-SAME: ptrAuthIsAddressDiscriminated: false
+// CHECK-SAME: ptrAuthExtraDiscriminator: 15253
+// CHECK-SAME: ptrAuthIsaPointer: false
+// CHECK-SAME: ptrAuthAuthenticatesNullValues: false
+
+// CHECK:      [[BASE1]] = !DIDerivedType(tag: DW_TAG_ptr_to_member_type
+// CHECK-SAME: baseType: [[BASE2:![0-9]+]]
+
+// CHECK:      [[BASE2]] = !DISubroutineType
+
+struct A {
+  void foo() {};
+};
+
+typedef void (A::*fptr)();
+
+fptr x = &A::foo;

clang/test/CodeGen/ptrauth-debuginfo.c

@@ -39,6 +39,17 @@ void f() {
 // CHECK-SAME:           ptrAuthIsaPointer: false,
 // CHECK-SAME:           ptrAuthAuthenticatesNullValues: false)
 
+/* Block descriptor signed function type. The same is used for further block
+ * descriptors, so checking only once. */
+
+// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "__FuncPtr",
+// CHECK-SAME:           baseType: [[BASE1:![0-9]+]],
+
+// CHECK: [[BASE1]] = !DIDerivedType(tag: DW_TAG_LLVM_ptrauth_type,
+// CHECK-SAME:                       ptrAuthIsAddressDiscriminated: false,
+// CHECK-SAME:                       ptrAuthIsaPointer: false,
+// CHECK-SAME:                       ptrAuthAuthenticatesNullValues: false)
+
 void f2() {
   __block struct A *__ptrauth(1, 1, 1237, "isa-pointer") ptr = createA();
   ^{