Merge pull request swiftlang#74384 from apple/gaborh/print-decl-order

[cxx-interop] Fix generated declaration order

Author: Xazax-hun

lib/PrintAsClang/ModuleContentsWriter.cpp

@@ -20,6 +20,7 @@
 #include "PrintSwiftToClangCoreScaffold.h"
 #include "SwiftToClangInteropContext.h"
 
+#include "swift/AST/Decl.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/Module.h"
@@ -671,6 +672,15 @@ class ModuleWriter {
         llvm_unreachable("unknown top-level ObjC decl");
       };
 
+      // When we visit a function, we might also generate a thunk that calls into the
+      // implementation of structs/enums to get the opaque pointers. To avoid
+      // referencing these methods before we see the definition for the generated
+      // classes, we want to visit function definitions last.
+      if (isa<AbstractFunctionDecl>(*rhs) && isa<NominalTypeDecl>(*lhs))
+        return Descending;
+      if (isa<AbstractFunctionDecl>(*lhs) && isa<NominalTypeDecl>(*rhs))
+        return Ascending;
+
       // Sort by names.
       int result = getSortName(*rhs).compare(getSortName(*lhs));
       if (result != 0)
@@ -700,9 +710,9 @@ class ModuleWriter {
       // even when the variable might not actually be emitted by the emitter.
       // In that case, order the function before the variable.
       if (isa<AbstractFunctionDecl>(*rhs) && isa<VarDecl>(*lhs))
-        return 1;
+        return Descending;
       if (isa<AbstractFunctionDecl>(*lhs) && isa<VarDecl>(*rhs))
-        return -1;
+        return Ascending;
 
       // Prefer value decls to extensions.
       assert(!(isa<ValueDecl>(*lhs) && isa<ValueDecl>(*rhs)));

test/Interop/SwiftToCxx/class/swift-class-in-cxx.swift

@@ -102,14 +102,14 @@ public final class ClassWithIntField {
 // CHECK-EMPTY:
 // CHECK-NEXT: namespace Class SWIFT_PRIVATE_ATTR SWIFT_SYMBOL_MODULE("Class") {
 
-// CHECK: SWIFT_INLINE_THUNK ClassWithIntField passThroughClassWithIntField(const ClassWithIntField& x) noexcept SWIFT_SYMBOL("s:5Class011passThroughA12WithIntFieldyAA0adeF0CADF") SWIFT_WARN_UNUSED_RESULT {
-// CHECK-NEXT:  return _impl::_impl_ClassWithIntField::makeRetained(_impl::$s5Class011passThroughA12WithIntFieldyAA0adeF0CADF(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(x)));
-// CHECK-NEXT: }
-
 public final class register { }
 
 // CHECK: class SWIFT_SYMBOL("s:5Class8registerC") register_ final : public swift::_impl::RefCountedClass {
 
+// CHECK: SWIFT_INLINE_THUNK ClassWithIntField passThroughClassWithIntField(const ClassWithIntField& x) noexcept SWIFT_SYMBOL("s:5Class011passThroughA12WithIntFieldyAA0adeF0CADF") SWIFT_WARN_UNUSED_RESULT {
+// CHECK-NEXT:  return _impl::_impl_ClassWithIntField::makeRetained(_impl::$s5Class011passThroughA12WithIntFieldyAA0adeF0CADF(::swift::_impl::_impl_RefCountedClass::getOpaquePointer(x)));
+// CHECK-NEXT: }
+
 public func returnClassWithIntField() -> ClassWithIntField {
   return ClassWithIntField()
 }

test/Interop/SwiftToCxx/functions/swift-operators.swift

@@ -2,9 +2,7 @@
 // RUN: %target-swift-frontend %s -typecheck -module-name Operators -clang-header-expose-decls=all-public -emit-clang-header-path %t/operators.h
 // RUN: %FileCheck %s < %t/operators.h
 
-// TODO: %check-interop-cxx-header-in-clang(%t/operators.h)
-// unfortunately the header still triggers an error:
-//   error: no member named '_impl_IntBox' in namespace 'Operators::_impl'
+// RUN: %check-interop-cxx-header-in-clang(%t/operators.h)
 
 // CHECK-LABEL: namespace Operators SWIFT_PRIVATE_ATTR SWIFT_SYMBOL_MODULE("Operators") {