[interop][SwiftToCxx] dispatch swift class methods using signed isa a…

include/swift/IRGen/IRABIDetailsProvider.h

@@ -258,13 +258,19 @@ class IRABIDetailsProvider {
       /// The call should be made via the provided thunk function.
       Thunk
     };
+    struct PointerAuthDiscriminator {
+      /// The value of the other discriminator
+      uint64_t value;
+    };
 
     static MethodDispatchInfo direct() {
       return MethodDispatchInfo(Kind::Direct, 0);
     }
 
-    static MethodDispatchInfo indirectVTableStaticOffset(size_t bitOffset) {
-      return MethodDispatchInfo(Kind::IndirectVTableStaticOffset, bitOffset);
+    static MethodDispatchInfo indirectVTableStaticOffset(
+        size_t bitOffset, Optional<PointerAuthDiscriminator> discriminator) {
+      return MethodDispatchInfo(Kind::IndirectVTableStaticOffset, bitOffset, "",
+                                discriminator);
     }
 
     static MethodDispatchInfo thunk(std::string thunkName) {
@@ -276,18 +282,25 @@ class IRABIDetailsProvider {
       assert(kind == Kind::IndirectVTableStaticOffset);
       return bitOffset;
     }
+    Optional<PointerAuthDiscriminator> getPointerAuthDiscriminator() const {
+      assert(kind == Kind::IndirectVTableStaticOffset);
+      return discriminator;
+    }
     StringRef getThunkSymbolName() const {
       assert(kind == Kind::Thunk);
       return thunkName;
     }
 
   private:
-    MethodDispatchInfo(Kind kind, size_t bitOffset, std::string thunkName = "")
-        : kind(kind), bitOffset(bitOffset), thunkName(thunkName) {}
+    MethodDispatchInfo(Kind kind, size_t bitOffset, std::string thunkName = "",
+                       Optional<PointerAuthDiscriminator> discriminator = None)
+        : kind(kind), bitOffset(bitOffset), thunkName(thunkName),
+          discriminator(discriminator) {}
 
     Kind kind;
     size_t bitOffset;
     std::string thunkName;
+    Optional<PointerAuthDiscriminator> discriminator;
   };
 
   Optional<MethodDispatchInfo>

lib/IRGen/IRABIDetailsProvider.cpp

@@ -14,6 +14,7 @@
 #include "Callee.h"
 #include "FixedTypeInfo.h"
 #include "GenEnum.h"
+#include "GenPointerAuth.h"
 #include "GenType.h"
 #include "GenericRequirement.h"
 #include "IRGen.h"
@@ -206,6 +207,21 @@ class IRABIDetailsProviderImpl {
 
   using MethodDispatchInfo = IRABIDetailsProvider::MethodDispatchInfo;
 
+  Optional<MethodDispatchInfo::PointerAuthDiscriminator>
+  getMethodPointerAuthInfo(const AbstractFunctionDecl *funcDecl,
+                           SILDeclRef method) {
+    // FIXME: Async support.
+    if (funcDecl->hasAsync())
+      return None;
+    const auto &schema = IGM.getOptions().PointerAuth.SwiftClassMethods;
+    if (!schema)
+      return None;
+    auto discriminator =
+        PointerAuthInfo::getOtherDiscriminator(IGM, schema, method);
+    return MethodDispatchInfo::PointerAuthDiscriminator{
+        discriminator->getZExtValue()};
+  }
+
   Optional<MethodDispatchInfo>
   getMethodDispatchInfo(const AbstractFunctionDecl *funcDecl) {
     if (funcDecl->isSemanticallyFinal())
@@ -227,8 +243,8 @@ class IRABIDetailsProviderImpl {
     if (!isa<ClassMetadataLayout>(layout))
       return {};
     auto &classLayout = cast<ClassMetadataLayout>(layout);
-    auto *mi = classLayout.getStoredMethodInfoIfPresent(
-        SILDeclRef(const_cast<AbstractFunctionDecl *>(funcDecl)));
+    auto silDecl = SILDeclRef(const_cast<AbstractFunctionDecl *>(funcDecl));
+    auto *mi = classLayout.getStoredMethodInfoIfPresent(silDecl);
     if (!mi)
       return {};
     switch (mi->TheKind) {
@@ -237,7 +253,8 @@ class IRABIDetailsProviderImpl {
     case ClassMetadataLayout::MethodInfo::Kind::Offset:
       if (mi->TheOffset.isStatic()) {
         return MethodDispatchInfo::indirectVTableStaticOffset(
-            /*bitOffset=*/mi->TheOffset.getStaticOffset().getValue());
+            /*bitOffset=*/mi->TheOffset.getStaticOffset().getValue(),
+            getMethodPointerAuthInfo(funcDecl, silDecl));
       }
       return {};
     }

lib/PrintAsClang/PrintClangFunction.cpp

@@ -18,6 +18,7 @@
 #include "PrintClangClassType.h"
 #include "PrintClangValueType.h"
 #include "SwiftToClangInteropContext.h"
+#include "swift/ABI/MetadataValues.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/GenericParamList.h"
 #include "swift/AST/Module.h"
@@ -1107,13 +1108,27 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
       os << "void ***selfPtr_ = reinterpret_cast<void ***>( "
             "::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));"
             "\n";
+
+      os << "#ifdef __arm64e__\n";
+      os << "void **vtable_ = ptrauth_auth_data(*selfPtr_, "
+            "ptrauth_key_process_independent_data, "
+            "ptrauth_blend_discriminator(selfPtr_,"
+         << SpecialPointerAuthDiscriminators::ObjCISA << "));\n";
+      os << "#else\n";
       os << "void **vtable_ = *selfPtr_;\n";
-      os << "using FType = decltype("
-         << cxx_synthesis::getCxxImplNamespaceName() << "::" << swiftSymbolName
-         << ");\n";
-      os << "FType *fptr_ = reinterpret_cast<FType *>(*(vtable_ + "
-         << (dispatchInfo->getStaticBitOffset() / 8) << "));\n";
-      indirectFunctionVar = StringRef("fptr_");
+      os << "#endif\n";
+      os << "struct FTypeAddress {\n";
+      os << "decltype(" << cxx_synthesis::getCxxImplNamespaceName()
+         << "::" << swiftSymbolName << ") *";
+      if (auto ptrAuthDisc = dispatchInfo->getPointerAuthDiscriminator())
+        os << " __ptrauth_swift_class_method_pointer(" << ptrAuthDisc->value
+           << ')';
+      os << " func;\n";
+      os << "};\n";
+      os << "FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ "
+            "+ "
+         << (dispatchInfo->getStaticBitOffset() / 8) << ");\n";
+      indirectFunctionVar = StringRef("fptrptr_->func");
       break;
     case DispatchKindTy::Thunk:
       swiftSymbolName = dispatchInfo->getThunkSymbolName();

test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch-arm64e.swift

@@ -0,0 +1,24 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %S/swift-class-virtual-method-dispatch.swift -target arm64e-apple-ios12.0 -typecheck -module-name Class -clang-header-expose-decls=all-public -emit-clang-header-path %t/class.h
+// RUN: %FileCheck %s < %t/class.h
+
+// RUN: %check-interop-cxx-header-in-clang(%t/class.h)
+
+// REQUIRES: CPU=arm64e
+// REQUIRES: OS=ios
+
+// note: uses swift-class-virtual-method-dispatch.swift
+
+// CHECK:      void BaseClass::virtualMethod() {
+// CHECK-NEXT: void ***selfPtr_ = reinterpret_cast<void ***>( ::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
+// CHECK-NEXT: #ifdef __arm64e__
+// CHECK-NEXT: void **vtable_ = ptrauth_auth_data(*selfPtr_, ptrauth_key_process_independent_data, ptrauth_blend_discriminator(selfPtr_,27361));
+// CHECK-NEXT: #else
+// CHECK-NEXT: void **vtable_ = *selfPtr_;
+// CHECK-NEXT: #endif
+// CHECK-NEXT: struct FTypeAddress {
+// CHECK-NEXT: decltype(_impl::$s5Class04BaseA0C13virtualMethodyyF) * __ptrauth_swift_class_method_pointer([[#AUTH:]]) func;
+// CHECK-NEXT: };
+// CHECK-NEXT: FTypeAddress *fptrptr_ = reinterpret_cast<FTypeAddress *>(vtable_ + [[#VM1:]]);
+// CHECK-NEXT: return (* fptrptr_->func)(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(*this));
+// CHECK-NEXT: }

test/Interop/SwiftToCxx/class/swift-class-virtual-method-dispatch-execution.cpp

@@ -8,9 +8,6 @@
 // RUN: %target-codesign %t/swift-class-execution
 // RUN: %target-run %t/swift-class-execution | %FileCheck %s
 
-// FIXME: pointer signing support.
-// UNSUPPORTED: CPU=arm64e
-
 // REQUIRES: executable_test
 
 #include "class.h"