fallback to SwiftASTContext for unsupported cases

Author: kastiglione

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.cpp

@@ -2786,7 +2786,7 @@ bool TypeSystemSwiftTypeRef::DumpTypeValue(
     size_t data_byte_size, uint32_t bitfield_bit_size,
     uint32_t bitfield_bit_offset, ExecutionContextScope *exe_scope,
     bool is_base_class) {
-  auto impl = [&]() -> bool {
+  auto impl = [&]() -> llvm::Optional<bool> {
     if (!type)
       return false;
 
@@ -2892,17 +2892,34 @@ bool TypeSystemSwiftTypeRef::DumpTypeValue(
   };
 
 #ifndef NDEBUG
+  auto result = impl();
+  if (!result) {
+    if (!m_swift_ast_context)
+      return false;
+    // Swift reflection provided no result, fallback to the AST.
+    return m_swift_ast_context->DumpTypeValue(
+        ReconstructType(type), s, format, data, data_offset, data_byte_size,
+        bitfield_bit_size, bitfield_bit_offset, exe_scope, is_base_class);
+  }
+  auto ast_type = ReconstructType(type);
+  if (!ast_type)
+    return false; /* missing .swiftmodule */
   StreamString ast_s;
-  auto defer = llvm::make_scope_exit([&] {
-    assert(Equivalent(ConstString(ast_s.GetString()),
-                      ConstString(((StreamString *)s)->GetString())) &&
-           "TypeSystemSwiftTypeRef diverges from SwiftASTContext");
-  });
+  bool eq_result =
+      Equivalent(result, m_swift_ast_context->DumpTypeValue(
+                             ast_type, &ast_s, format, data, data_offset,
+                             data_byte_size, bitfield_bit_size,
+                             bitfield_bit_offset, exe_scope, is_base_class));
+  bool eq_stream = Equivalent(ConstString(ast_s.GetString()),
+                              ConstString(((StreamString *)s)->GetString()));
+  if (!eq_result || !eq_stream)
+    llvm::dbgs() << "failing type was " << (const char *)type << "\n";
+  assert(eq_result && eq_stream &&
+         "TypeSystemSwiftTypeRef diverges from SwiftASTContext");
+  return *result;
+#else
+  return impl().getValueOr(false);
 #endif
-  VALIDATE_AND_RETURN(impl, DumpTypeValue, type,
-                      (ReconstructType(type), &ast_s, format, data, data_offset,
-                       data_byte_size, bitfield_bit_size, bitfield_bit_offset,
-                       exe_scope, is_base_class));
 }
 
 void TypeSystemSwiftTypeRef::DumpTypeDescription(opaque_compiler_type_t type,